Upgrade to 3.29
Update V8 to 3.29.88.17 and update makefiles to support building on
all the relevant platforms.
Bug: 17370214
Change-Id: Ia3407c157fd8d72a93e23d8318ccaf6ecf77fa4e
diff --git a/src/heap/gc-idle-time-handler-unittest.cc b/src/heap/gc-idle-time-handler-unittest.cc
new file mode 100644
index 0000000..b4f2f74
--- /dev/null
+++ b/src/heap/gc-idle-time-handler-unittest.cc
@@ -0,0 +1,348 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <limits>
+
+#include "src/heap/gc-idle-time-handler.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace v8 {
+namespace internal {
+
+namespace {
+
+class GCIdleTimeHandlerTest : public ::testing::Test {
+ public:
+ GCIdleTimeHandlerTest() {}
+ virtual ~GCIdleTimeHandlerTest() {}
+
+ GCIdleTimeHandler* handler() { return &handler_; }
+
+ GCIdleTimeHandler::HeapState DefaultHeapState() {
+ GCIdleTimeHandler::HeapState result;
+ result.contexts_disposed = 0;
+ result.size_of_objects = kSizeOfObjects;
+ result.incremental_marking_stopped = false;
+ result.can_start_incremental_marking = true;
+ result.sweeping_in_progress = false;
+ result.mark_compact_speed_in_bytes_per_ms = kMarkCompactSpeed;
+ result.incremental_marking_speed_in_bytes_per_ms = kMarkingSpeed;
+ result.scavenge_speed_in_bytes_per_ms = kScavengeSpeed;
+ result.available_new_space_memory = kNewSpaceCapacity;
+ result.new_space_capacity = kNewSpaceCapacity;
+ result.new_space_allocation_throughput_in_bytes_per_ms =
+ kNewSpaceAllocationThroughput;
+ return result;
+ }
+
+ static const size_t kSizeOfObjects = 100 * MB;
+ static const size_t kMarkCompactSpeed = 200 * KB;
+ static const size_t kMarkingSpeed = 200 * KB;
+ static const size_t kScavengeSpeed = 100 * KB;
+ static const size_t kNewSpaceCapacity = 1 * MB;
+ static const size_t kNewSpaceAllocationThroughput = 10 * KB;
+
+ private:
+ GCIdleTimeHandler handler_;
+};
+
+} // namespace
+
+
+TEST(GCIdleTimeHandler, EstimateMarkingStepSizeInitial) {
+ size_t step_size = GCIdleTimeHandler::EstimateMarkingStepSize(1, 0);
+ EXPECT_EQ(
+ static_cast<size_t>(GCIdleTimeHandler::kInitialConservativeMarkingSpeed *
+ GCIdleTimeHandler::kConservativeTimeRatio),
+ step_size);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateMarkingStepSizeNonZero) {
+ size_t marking_speed_in_bytes_per_millisecond = 100;
+ size_t step_size = GCIdleTimeHandler::EstimateMarkingStepSize(
+ 1, marking_speed_in_bytes_per_millisecond);
+ EXPECT_EQ(static_cast<size_t>(marking_speed_in_bytes_per_millisecond *
+ GCIdleTimeHandler::kConservativeTimeRatio),
+ step_size);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateMarkingStepSizeOverflow1) {
+ size_t step_size = GCIdleTimeHandler::EstimateMarkingStepSize(
+ 10, std::numeric_limits<size_t>::max());
+ EXPECT_EQ(static_cast<size_t>(GCIdleTimeHandler::kMaximumMarkingStepSize),
+ step_size);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateMarkingStepSizeOverflow2) {
+ size_t step_size = GCIdleTimeHandler::EstimateMarkingStepSize(
+ std::numeric_limits<size_t>::max(), 10);
+ EXPECT_EQ(static_cast<size_t>(GCIdleTimeHandler::kMaximumMarkingStepSize),
+ step_size);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateMarkCompactTimeInitial) {
+ size_t size = 100 * MB;
+ size_t time = GCIdleTimeHandler::EstimateMarkCompactTime(size, 0);
+ EXPECT_EQ(size / GCIdleTimeHandler::kInitialConservativeMarkCompactSpeed,
+ time);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateMarkCompactTimeNonZero) {
+ size_t size = 100 * MB;
+ size_t speed = 1 * MB;
+ size_t time = GCIdleTimeHandler::EstimateMarkCompactTime(size, speed);
+ EXPECT_EQ(size / speed, time);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateMarkCompactTimeMax) {
+ size_t size = std::numeric_limits<size_t>::max();
+ size_t speed = 1;
+ size_t time = GCIdleTimeHandler::EstimateMarkCompactTime(size, speed);
+ EXPECT_EQ(GCIdleTimeHandler::kMaxMarkCompactTimeInMs, time);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateScavengeTimeInitial) {
+ size_t size = 1 * MB;
+ size_t time = GCIdleTimeHandler::EstimateScavengeTime(size, 0);
+ EXPECT_EQ(size / GCIdleTimeHandler::kInitialConservativeScavengeSpeed, time);
+}
+
+
+TEST(GCIdleTimeHandler, EstimateScavengeTimeNonZero) {
+ size_t size = 1 * MB;
+ size_t speed = 1 * MB;
+ size_t time = GCIdleTimeHandler::EstimateScavengeTime(size, speed);
+ EXPECT_EQ(size / speed, time);
+}
+
+
+TEST(GCIdleTimeHandler, ScavangeMayHappenSoonInitial) {
+ size_t available = 100 * KB;
+ EXPECT_FALSE(GCIdleTimeHandler::ScavangeMayHappenSoon(available, 0));
+}
+
+
+TEST(GCIdleTimeHandler, ScavangeMayHappenSoonNonZeroFalse) {
+ size_t available = (GCIdleTimeHandler::kMaxFrameRenderingIdleTime + 1) * KB;
+ size_t speed = 1 * KB;
+ EXPECT_FALSE(GCIdleTimeHandler::ScavangeMayHappenSoon(available, speed));
+}
+
+
+TEST(GCIdleTimeHandler, ScavangeMayHappenSoonNonZeroTrue) {
+ size_t available = GCIdleTimeHandler::kMaxFrameRenderingIdleTime * KB;
+ size_t speed = 1 * KB;
+ EXPECT_TRUE(GCIdleTimeHandler::ScavangeMayHappenSoon(available, speed));
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, AfterContextDisposeLargeIdleTime) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ heap_state.contexts_disposed = 1;
+ heap_state.incremental_marking_stopped = true;
+ size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
+ int idle_time_ms =
+ static_cast<int>((heap_state.size_of_objects + speed - 1) / speed);
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_FULL_GC, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, AfterContextDisposeSmallIdleTime1) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ heap_state.contexts_disposed = 1;
+ heap_state.incremental_marking_stopped = true;
+ size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
+ int idle_time_ms = static_cast<int>(heap_state.size_of_objects / speed - 1);
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, AfterContextDisposeSmallIdleTime2) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ heap_state.contexts_disposed = 1;
+ size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
+ int idle_time_ms = static_cast<int>(heap_state.size_of_objects / speed - 1);
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, IncrementalMarking1) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ size_t speed = heap_state.incremental_marking_speed_in_bytes_per_ms;
+ int idle_time_ms = 10;
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+ EXPECT_GT(speed * static_cast<size_t>(idle_time_ms),
+ static_cast<size_t>(action.parameter));
+ EXPECT_LT(0, action.parameter);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, IncrementalMarking2) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ heap_state.incremental_marking_stopped = true;
+ size_t speed = heap_state.incremental_marking_speed_in_bytes_per_ms;
+ int idle_time_ms = 10;
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+ EXPECT_GT(speed * static_cast<size_t>(idle_time_ms),
+ static_cast<size_t>(action.parameter));
+ EXPECT_LT(0, action.parameter);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, NotEnoughTime) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ heap_state.incremental_marking_stopped = true;
+ heap_state.can_start_incremental_marking = false;
+ size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
+ int idle_time_ms = static_cast<int>(heap_state.size_of_objects / speed - 1);
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_NOTHING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, StopEventually1) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ heap_state.incremental_marking_stopped = true;
+ heap_state.can_start_incremental_marking = false;
+ size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
+ int idle_time_ms = static_cast<int>(heap_state.size_of_objects / speed + 1);
+ for (int i = 0; i < GCIdleTimeHandler::kMaxMarkCompactsInIdleRound; i++) {
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_FULL_GC, action.type);
+ handler()->NotifyIdleMarkCompact();
+ }
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DONE, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, StopEventually2) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ int idle_time_ms = 10;
+ for (int i = 0; i < GCIdleTimeHandler::kMaxMarkCompactsInIdleRound; i++) {
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+ // In this case we emulate incremental marking steps that finish with a
+ // full gc.
+ handler()->NotifyIdleMarkCompact();
+ }
+ heap_state.can_start_incremental_marking = false;
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DONE, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, ContinueAfterStop1) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ heap_state.incremental_marking_stopped = true;
+ heap_state.can_start_incremental_marking = false;
+ size_t speed = heap_state.mark_compact_speed_in_bytes_per_ms;
+ int idle_time_ms = static_cast<int>(heap_state.size_of_objects / speed + 1);
+ for (int i = 0; i < GCIdleTimeHandler::kMaxMarkCompactsInIdleRound; i++) {
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_FULL_GC, action.type);
+ handler()->NotifyIdleMarkCompact();
+ }
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DONE, action.type);
+ // Emulate mutator work.
+ for (int i = 0; i < GCIdleTimeHandler::kIdleScavengeThreshold; i++) {
+ handler()->NotifyScavenge();
+ }
+ action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_FULL_GC, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, ContinueAfterStop2) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ int idle_time_ms = 10;
+ for (int i = 0; i < GCIdleTimeHandler::kMaxMarkCompactsInIdleRound; i++) {
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ if (action.type == DONE) break;
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+ // In this case we try to emulate incremental marking steps the finish with
+ // a full gc.
+ handler()->NotifyIdleMarkCompact();
+ }
+ heap_state.can_start_incremental_marking = false;
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DONE, action.type);
+ // Emulate mutator work.
+ for (int i = 0; i < GCIdleTimeHandler::kIdleScavengeThreshold; i++) {
+ handler()->NotifyScavenge();
+ }
+ heap_state.can_start_incremental_marking = true;
+ action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, Scavenge) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ int idle_time_ms = 10;
+ heap_state.available_new_space_memory =
+ kNewSpaceAllocationThroughput * idle_time_ms;
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_SCAVENGE, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, ScavengeAndDone) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ int idle_time_ms = 10;
+ heap_state.can_start_incremental_marking = false;
+ heap_state.incremental_marking_stopped = true;
+ heap_state.available_new_space_memory =
+ kNewSpaceAllocationThroughput * idle_time_ms;
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_SCAVENGE, action.type);
+ heap_state.available_new_space_memory = kNewSpaceCapacity;
+ action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_NOTHING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, ZeroIdleTimeNothingToDo) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ int idle_time_ms = 0;
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ EXPECT_EQ(DO_NOTHING, action.type);
+}
+
+
+TEST_F(GCIdleTimeHandlerTest, ZeroIdleTimeDoNothingButStartIdleRound) {
+ GCIdleTimeHandler::HeapState heap_state = DefaultHeapState();
+ int idle_time_ms = 10;
+ for (int i = 0; i < GCIdleTimeHandler::kMaxMarkCompactsInIdleRound; i++) {
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ if (action.type == DONE) break;
+ EXPECT_EQ(DO_INCREMENTAL_MARKING, action.type);
+ // In this case we try to emulate incremental marking steps the finish with
+ // a full gc.
+ handler()->NotifyIdleMarkCompact();
+ }
+ GCIdleTimeAction action = handler()->Compute(idle_time_ms, heap_state);
+ // Emulate mutator work.
+ for (int i = 0; i < GCIdleTimeHandler::kIdleScavengeThreshold; i++) {
+ handler()->NotifyScavenge();
+ }
+ action = handler()->Compute(0, heap_state);
+ EXPECT_EQ(DO_NOTHING, action.type);
+}
+
+} // namespace internal
+} // namespace v8
diff --git a/src/heap/gc-idle-time-handler.cc b/src/heap/gc-idle-time-handler.cc
new file mode 100644
index 0000000..b9a99b2
--- /dev/null
+++ b/src/heap/gc-idle-time-handler.cc
@@ -0,0 +1,174 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/heap/gc-idle-time-handler.h"
+#include "src/heap/gc-tracer.h"
+#include "src/utils.h"
+
+namespace v8 {
+namespace internal {
+
+const double GCIdleTimeHandler::kConservativeTimeRatio = 0.9;
+const size_t GCIdleTimeHandler::kMaxMarkCompactTimeInMs = 1000;
+const size_t GCIdleTimeHandler::kMinTimeForFinalizeSweeping = 100;
+const int GCIdleTimeHandler::kMaxMarkCompactsInIdleRound = 7;
+const int GCIdleTimeHandler::kIdleScavengeThreshold = 5;
+
+
+void GCIdleTimeAction::Print() {
+ switch (type) {
+ case DONE:
+ PrintF("done");
+ break;
+ case DO_NOTHING:
+ PrintF("no action");
+ break;
+ case DO_INCREMENTAL_MARKING:
+ PrintF("incremental marking with step %" V8_PTR_PREFIX "d", parameter);
+ break;
+ case DO_SCAVENGE:
+ PrintF("scavenge");
+ break;
+ case DO_FULL_GC:
+ PrintF("full GC");
+ break;
+ case DO_FINALIZE_SWEEPING:
+ PrintF("finalize sweeping");
+ break;
+ }
+}
+
+
+size_t GCIdleTimeHandler::EstimateMarkingStepSize(
+ size_t idle_time_in_ms, size_t marking_speed_in_bytes_per_ms) {
+ DCHECK(idle_time_in_ms > 0);
+
+ if (marking_speed_in_bytes_per_ms == 0) {
+ marking_speed_in_bytes_per_ms = kInitialConservativeMarkingSpeed;
+ }
+
+ size_t marking_step_size = marking_speed_in_bytes_per_ms * idle_time_in_ms;
+ if (marking_step_size / marking_speed_in_bytes_per_ms != idle_time_in_ms) {
+ // In the case of an overflow we return maximum marking step size.
+ return kMaximumMarkingStepSize;
+ }
+
+ if (marking_step_size > kMaximumMarkingStepSize)
+ return kMaximumMarkingStepSize;
+
+ return static_cast<size_t>(marking_step_size * kConservativeTimeRatio);
+}
+
+
+size_t GCIdleTimeHandler::EstimateMarkCompactTime(
+ size_t size_of_objects, size_t mark_compact_speed_in_bytes_per_ms) {
+ if (mark_compact_speed_in_bytes_per_ms == 0) {
+ mark_compact_speed_in_bytes_per_ms = kInitialConservativeMarkCompactSpeed;
+ }
+ size_t result = size_of_objects / mark_compact_speed_in_bytes_per_ms;
+ return Min(result, kMaxMarkCompactTimeInMs);
+}
+
+
+size_t GCIdleTimeHandler::EstimateScavengeTime(
+ size_t new_space_size, size_t scavenge_speed_in_bytes_per_ms) {
+ if (scavenge_speed_in_bytes_per_ms == 0) {
+ scavenge_speed_in_bytes_per_ms = kInitialConservativeScavengeSpeed;
+ }
+ return new_space_size / scavenge_speed_in_bytes_per_ms;
+}
+
+
+bool GCIdleTimeHandler::ScavangeMayHappenSoon(
+ size_t available_new_space_memory,
+ size_t new_space_allocation_throughput_in_bytes_per_ms) {
+ if (available_new_space_memory <=
+ new_space_allocation_throughput_in_bytes_per_ms *
+ kMaxFrameRenderingIdleTime) {
+ return true;
+ }
+ return false;
+}
+
+
+// The following logic is implemented by the controller:
+// (1) If the new space is almost full and we can effort a Scavenge, then a
+// Scavenge is performed.
+// (2) If there is currently no MarkCompact idle round going on, we start a
+// new idle round if enough garbage was created or we received a context
+// disposal event. Otherwise we do not perform garbage collection to keep
+// system utilization low.
+// (3) If incremental marking is done, we perform a full garbage collection
+// if context was disposed or if we are allowed to still do full garbage
+// collections during this idle round or if we are not allowed to start
+// incremental marking. Otherwise we do not perform garbage collection to
+// keep system utilization low.
+// (4) If sweeping is in progress and we received a large enough idle time
+// request, we finalize sweeping here.
+// (5) If incremental marking is in progress, we perform a marking step. Note,
+// that this currently may trigger a full garbage collection.
+GCIdleTimeAction GCIdleTimeHandler::Compute(size_t idle_time_in_ms,
+ HeapState heap_state) {
+ if (idle_time_in_ms <= kMaxFrameRenderingIdleTime &&
+ ScavangeMayHappenSoon(
+ heap_state.available_new_space_memory,
+ heap_state.new_space_allocation_throughput_in_bytes_per_ms) &&
+ idle_time_in_ms >=
+ EstimateScavengeTime(heap_state.new_space_capacity,
+ heap_state.scavenge_speed_in_bytes_per_ms)) {
+ return GCIdleTimeAction::Scavenge();
+ }
+ if (IsMarkCompactIdleRoundFinished()) {
+ if (EnoughGarbageSinceLastIdleRound() || heap_state.contexts_disposed > 0) {
+ StartIdleRound();
+ } else {
+ return GCIdleTimeAction::Done();
+ }
+ }
+
+ if (idle_time_in_ms == 0) {
+ return GCIdleTimeAction::Nothing();
+ }
+
+ if (heap_state.incremental_marking_stopped) {
+ size_t estimated_time_in_ms =
+ EstimateMarkCompactTime(heap_state.size_of_objects,
+ heap_state.mark_compact_speed_in_bytes_per_ms);
+ if (idle_time_in_ms >= estimated_time_in_ms ||
+ (heap_state.size_of_objects < kSmallHeapSize &&
+ heap_state.contexts_disposed > 0)) {
+ // If there are no more than two GCs left in this idle round and we are
+ // allowed to do a full GC, then make those GCs full in order to compact
+ // the code space.
+ // TODO(ulan): Once we enable code compaction for incremental marking, we
+ // can get rid of this special case and always start incremental marking.
+ int remaining_mark_sweeps =
+ kMaxMarkCompactsInIdleRound - mark_compacts_since_idle_round_started_;
+ if (heap_state.contexts_disposed > 0 ||
+ (idle_time_in_ms > kMaxFrameRenderingIdleTime &&
+ (remaining_mark_sweeps <= 2 ||
+ !heap_state.can_start_incremental_marking))) {
+ return GCIdleTimeAction::FullGC();
+ }
+ }
+ if (!heap_state.can_start_incremental_marking) {
+ return GCIdleTimeAction::Nothing();
+ }
+ }
+ // TODO(hpayer): Estimate finalize sweeping time.
+ if (heap_state.sweeping_in_progress &&
+ idle_time_in_ms >= kMinTimeForFinalizeSweeping) {
+ return GCIdleTimeAction::FinalizeSweeping();
+ }
+
+ if (heap_state.incremental_marking_stopped &&
+ !heap_state.can_start_incremental_marking) {
+ return GCIdleTimeAction::Nothing();
+ }
+ size_t step_size = EstimateMarkingStepSize(
+ idle_time_in_ms, heap_state.incremental_marking_speed_in_bytes_per_ms);
+ return GCIdleTimeAction::IncrementalMarking(step_size);
+}
+}
+}
diff --git a/src/heap/gc-idle-time-handler.h b/src/heap/gc-idle-time-handler.h
new file mode 100644
index 0000000..daab616
--- /dev/null
+++ b/src/heap/gc-idle-time-handler.h
@@ -0,0 +1,188 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_GC_IDLE_TIME_HANDLER_H_
+#define V8_HEAP_GC_IDLE_TIME_HANDLER_H_
+
+#include "src/globals.h"
+
+namespace v8 {
+namespace internal {
+
+enum GCIdleTimeActionType {
+ DONE,
+ DO_NOTHING,
+ DO_INCREMENTAL_MARKING,
+ DO_SCAVENGE,
+ DO_FULL_GC,
+ DO_FINALIZE_SWEEPING
+};
+
+
+class GCIdleTimeAction {
+ public:
+ static GCIdleTimeAction Done() {
+ GCIdleTimeAction result;
+ result.type = DONE;
+ result.parameter = 0;
+ return result;
+ }
+
+ static GCIdleTimeAction Nothing() {
+ GCIdleTimeAction result;
+ result.type = DO_NOTHING;
+ result.parameter = 0;
+ return result;
+ }
+
+ static GCIdleTimeAction IncrementalMarking(intptr_t step_size) {
+ GCIdleTimeAction result;
+ result.type = DO_INCREMENTAL_MARKING;
+ result.parameter = step_size;
+ return result;
+ }
+
+ static GCIdleTimeAction Scavenge() {
+ GCIdleTimeAction result;
+ result.type = DO_SCAVENGE;
+ result.parameter = 0;
+ return result;
+ }
+
+ static GCIdleTimeAction FullGC() {
+ GCIdleTimeAction result;
+ result.type = DO_FULL_GC;
+ result.parameter = 0;
+ return result;
+ }
+
+ static GCIdleTimeAction FinalizeSweeping() {
+ GCIdleTimeAction result;
+ result.type = DO_FINALIZE_SWEEPING;
+ result.parameter = 0;
+ return result;
+ }
+
+ void Print();
+
+ GCIdleTimeActionType type;
+ intptr_t parameter;
+};
+
+
+class GCTracer;
+
+// The idle time handler makes decisions about which garbage collection
+// operations are executing during IdleNotification.
+class GCIdleTimeHandler {
+ public:
+ // If we haven't recorded any incremental marking events yet, we carefully
+ // mark with a conservative lower bound for the marking speed.
+ static const size_t kInitialConservativeMarkingSpeed = 100 * KB;
+
+ // Maximum marking step size returned by EstimateMarkingStepSize.
+ static const size_t kMaximumMarkingStepSize = 700 * MB;
+
+ // We have to make sure that we finish the IdleNotification before
+ // idle_time_in_ms. Hence, we conservatively prune our workload estimate.
+ static const double kConservativeTimeRatio;
+
+ // If we haven't recorded any mark-compact events yet, we use
+ // conservative lower bound for the mark-compact speed.
+ static const size_t kInitialConservativeMarkCompactSpeed = 2 * MB;
+
+ // Maximum mark-compact time returned by EstimateMarkCompactTime.
+ static const size_t kMaxMarkCompactTimeInMs;
+
+ // Minimum time to finalize sweeping phase. The main thread may wait for
+ // sweeper threads.
+ static const size_t kMinTimeForFinalizeSweeping;
+
+ // Number of idle mark-compact events, after which idle handler will finish
+ // idle round.
+ static const int kMaxMarkCompactsInIdleRound;
+
+ // Number of scavenges that will trigger start of new idle round.
+ static const int kIdleScavengeThreshold;
+
+ // Heap size threshold below which we prefer mark-compact over incremental
+ // step.
+ static const size_t kSmallHeapSize = 4 * kPointerSize * MB;
+
+ // That is the maximum idle time we will have during frame rendering.
+ static const size_t kMaxFrameRenderingIdleTime = 16;
+
+ // If less than that much memory is left in the new space, we consider it
+ // as almost full and force a new space collection earlier in the idle time.
+ static const size_t kNewSpaceAlmostFullTreshold = 100 * KB;
+
+ // If we haven't recorded any scavenger events yet, we use a conservative
+ // lower bound for the scavenger speed.
+ static const size_t kInitialConservativeScavengeSpeed = 100 * KB;
+
+ struct HeapState {
+ int contexts_disposed;
+ size_t size_of_objects;
+ bool incremental_marking_stopped;
+ bool can_start_incremental_marking;
+ bool sweeping_in_progress;
+ size_t mark_compact_speed_in_bytes_per_ms;
+ size_t incremental_marking_speed_in_bytes_per_ms;
+ size_t scavenge_speed_in_bytes_per_ms;
+ size_t available_new_space_memory;
+ size_t new_space_capacity;
+ size_t new_space_allocation_throughput_in_bytes_per_ms;
+ };
+
+ GCIdleTimeHandler()
+ : mark_compacts_since_idle_round_started_(0),
+ scavenges_since_last_idle_round_(0) {}
+
+ GCIdleTimeAction Compute(size_t idle_time_in_ms, HeapState heap_state);
+
+ void NotifyIdleMarkCompact() {
+ if (mark_compacts_since_idle_round_started_ < kMaxMarkCompactsInIdleRound) {
+ ++mark_compacts_since_idle_round_started_;
+ if (mark_compacts_since_idle_round_started_ ==
+ kMaxMarkCompactsInIdleRound) {
+ scavenges_since_last_idle_round_ = 0;
+ }
+ }
+ }
+
+ void NotifyScavenge() { ++scavenges_since_last_idle_round_; }
+
+ static size_t EstimateMarkingStepSize(size_t idle_time_in_ms,
+ size_t marking_speed_in_bytes_per_ms);
+
+ static size_t EstimateMarkCompactTime(
+ size_t size_of_objects, size_t mark_compact_speed_in_bytes_per_ms);
+
+ static size_t EstimateScavengeTime(size_t new_space_size,
+ size_t scavenger_speed_in_bytes_per_ms);
+
+ static bool ScavangeMayHappenSoon(
+ size_t available_new_space_memory,
+ size_t new_space_allocation_throughput_in_bytes_per_ms);
+
+ private:
+ void StartIdleRound() { mark_compacts_since_idle_round_started_ = 0; }
+ bool IsMarkCompactIdleRoundFinished() {
+ return mark_compacts_since_idle_round_started_ ==
+ kMaxMarkCompactsInIdleRound;
+ }
+ bool EnoughGarbageSinceLastIdleRound() {
+ return scavenges_since_last_idle_round_ >= kIdleScavengeThreshold;
+ }
+
+ int mark_compacts_since_idle_round_started_;
+ int scavenges_since_last_idle_round_;
+
+ DISALLOW_COPY_AND_ASSIGN(GCIdleTimeHandler);
+};
+
+} // namespace internal
+} // namespace v8
+
+#endif // V8_HEAP_GC_IDLE_TIME_HANDLER_H_
diff --git a/src/heap/gc-tracer.cc b/src/heap/gc-tracer.cc
new file mode 100644
index 0000000..8a40b53
--- /dev/null
+++ b/src/heap/gc-tracer.cc
@@ -0,0 +1,480 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#include "src/heap/gc-tracer.h"
+
+namespace v8 {
+namespace internal {
+
+static intptr_t CountTotalHolesSize(Heap* heap) {
+ intptr_t holes_size = 0;
+ OldSpaces spaces(heap);
+ for (OldSpace* space = spaces.next(); space != NULL; space = spaces.next()) {
+ holes_size += space->Waste() + space->Available();
+ }
+ return holes_size;
+}
+
+
+GCTracer::AllocationEvent::AllocationEvent(double duration,
+ intptr_t allocation_in_bytes) {
+ duration_ = duration;
+ allocation_in_bytes_ = allocation_in_bytes;
+}
+
+
+GCTracer::Event::Event(Type type, const char* gc_reason,
+ const char* collector_reason)
+ : type(type),
+ gc_reason(gc_reason),
+ collector_reason(collector_reason),
+ start_time(0.0),
+ end_time(0.0),
+ start_object_size(0),
+ end_object_size(0),
+ start_memory_size(0),
+ end_memory_size(0),
+ start_holes_size(0),
+ end_holes_size(0),
+ cumulative_incremental_marking_steps(0),
+ incremental_marking_steps(0),
+ cumulative_incremental_marking_bytes(0),
+ incremental_marking_bytes(0),
+ cumulative_incremental_marking_duration(0.0),
+ incremental_marking_duration(0.0),
+ cumulative_pure_incremental_marking_duration(0.0),
+ pure_incremental_marking_duration(0.0),
+ longest_incremental_marking_step(0.0) {
+ for (int i = 0; i < Scope::NUMBER_OF_SCOPES; i++) {
+ scopes[i] = 0;
+ }
+}
+
+
+const char* GCTracer::Event::TypeName(bool short_name) const {
+ switch (type) {
+ case SCAVENGER:
+ if (short_name) {
+ return "s";
+ } else {
+ return "Scavenge";
+ }
+ case MARK_COMPACTOR:
+ if (short_name) {
+ return "ms";
+ } else {
+ return "Mark-sweep";
+ }
+ case START:
+ if (short_name) {
+ return "st";
+ } else {
+ return "Start";
+ }
+ }
+ return "Unknown Event Type";
+}
+
+
+GCTracer::GCTracer(Heap* heap)
+ : heap_(heap),
+ cumulative_incremental_marking_steps_(0),
+ cumulative_incremental_marking_bytes_(0),
+ cumulative_incremental_marking_duration_(0.0),
+ cumulative_pure_incremental_marking_duration_(0.0),
+ longest_incremental_marking_step_(0.0),
+ cumulative_marking_duration_(0.0),
+ cumulative_sweeping_duration_(0.0),
+ new_space_top_after_gc_(0) {
+ current_ = Event(Event::START, NULL, NULL);
+ current_.end_time = base::OS::TimeCurrentMillis();
+ previous_ = previous_mark_compactor_event_ = current_;
+}
+
+
+void GCTracer::Start(GarbageCollector collector, const char* gc_reason,
+ const char* collector_reason) {
+ previous_ = current_;
+ double start_time = base::OS::TimeCurrentMillis();
+ if (new_space_top_after_gc_ != 0) {
+ AddNewSpaceAllocationTime(
+ start_time - previous_.end_time,
+ reinterpret_cast<intptr_t>((heap_->new_space()->top()) -
+ new_space_top_after_gc_));
+ }
+ if (current_.type == Event::MARK_COMPACTOR)
+ previous_mark_compactor_event_ = current_;
+
+ if (collector == SCAVENGER) {
+ current_ = Event(Event::SCAVENGER, gc_reason, collector_reason);
+ } else {
+ current_ = Event(Event::MARK_COMPACTOR, gc_reason, collector_reason);
+ }
+
+ current_.start_time = start_time;
+ current_.start_object_size = heap_->SizeOfObjects();
+ current_.start_memory_size = heap_->isolate()->memory_allocator()->Size();
+ current_.start_holes_size = CountTotalHolesSize(heap_);
+ current_.new_space_object_size =
+ heap_->new_space()->top() - heap_->new_space()->bottom();
+
+ current_.cumulative_incremental_marking_steps =
+ cumulative_incremental_marking_steps_;
+ current_.cumulative_incremental_marking_bytes =
+ cumulative_incremental_marking_bytes_;
+ current_.cumulative_incremental_marking_duration =
+ cumulative_incremental_marking_duration_;
+ current_.cumulative_pure_incremental_marking_duration =
+ cumulative_pure_incremental_marking_duration_;
+ current_.longest_incremental_marking_step = longest_incremental_marking_step_;
+
+ for (int i = 0; i < Scope::NUMBER_OF_SCOPES; i++) {
+ current_.scopes[i] = 0;
+ }
+}
+
+
+void GCTracer::Stop() {
+ current_.end_time = base::OS::TimeCurrentMillis();
+ current_.end_object_size = heap_->SizeOfObjects();
+ current_.end_memory_size = heap_->isolate()->memory_allocator()->Size();
+ current_.end_holes_size = CountTotalHolesSize(heap_);
+ new_space_top_after_gc_ =
+ reinterpret_cast<intptr_t>(heap_->new_space()->top());
+
+ if (current_.type == Event::SCAVENGER) {
+ current_.incremental_marking_steps =
+ current_.cumulative_incremental_marking_steps -
+ previous_.cumulative_incremental_marking_steps;
+ current_.incremental_marking_bytes =
+ current_.cumulative_incremental_marking_bytes -
+ previous_.cumulative_incremental_marking_bytes;
+ current_.incremental_marking_duration =
+ current_.cumulative_incremental_marking_duration -
+ previous_.cumulative_incremental_marking_duration;
+ current_.pure_incremental_marking_duration =
+ current_.cumulative_pure_incremental_marking_duration -
+ previous_.cumulative_pure_incremental_marking_duration;
+ scavenger_events_.push_front(current_);
+ } else {
+ current_.incremental_marking_steps =
+ current_.cumulative_incremental_marking_steps -
+ previous_mark_compactor_event_.cumulative_incremental_marking_steps;
+ current_.incremental_marking_bytes =
+ current_.cumulative_incremental_marking_bytes -
+ previous_mark_compactor_event_.cumulative_incremental_marking_bytes;
+ current_.incremental_marking_duration =
+ current_.cumulative_incremental_marking_duration -
+ previous_mark_compactor_event_.cumulative_incremental_marking_duration;
+ current_.pure_incremental_marking_duration =
+ current_.cumulative_pure_incremental_marking_duration -
+ previous_mark_compactor_event_
+ .cumulative_pure_incremental_marking_duration;
+ longest_incremental_marking_step_ = 0.0;
+ mark_compactor_events_.push_front(current_);
+ }
+
+ // TODO(ernstm): move the code below out of GCTracer.
+
+ if (!FLAG_trace_gc && !FLAG_print_cumulative_gc_stat) return;
+
+ double duration = current_.end_time - current_.start_time;
+ double spent_in_mutator = Max(current_.start_time - previous_.end_time, 0.0);
+
+ heap_->UpdateCumulativeGCStatistics(duration, spent_in_mutator,
+ current_.scopes[Scope::MC_MARK]);
+
+ if (current_.type == Event::SCAVENGER && FLAG_trace_gc_ignore_scavenger)
+ return;
+
+ if (FLAG_trace_gc) {
+ if (FLAG_trace_gc_nvp)
+ PrintNVP();
+ else
+ Print();
+
+ heap_->PrintShortHeapStatistics();
+ }
+}
+
+
+void GCTracer::AddNewSpaceAllocationTime(double duration,
+ intptr_t allocation_in_bytes) {
+ allocation_events_.push_front(AllocationEvent(duration, allocation_in_bytes));
+}
+
+
+void GCTracer::AddIncrementalMarkingStep(double duration, intptr_t bytes) {
+ cumulative_incremental_marking_steps_++;
+ cumulative_incremental_marking_bytes_ += bytes;
+ cumulative_incremental_marking_duration_ += duration;
+ longest_incremental_marking_step_ =
+ Max(longest_incremental_marking_step_, duration);
+ cumulative_marking_duration_ += duration;
+ if (bytes > 0) {
+ cumulative_pure_incremental_marking_duration_ += duration;
+ }
+}
+
+
+void GCTracer::Print() const {
+ PrintPID("%8.0f ms: ", heap_->isolate()->time_millis_since_init());
+
+ PrintF("%s %.1f (%.1f) -> %.1f (%.1f) MB, ", current_.TypeName(false),
+ static_cast<double>(current_.start_object_size) / MB,
+ static_cast<double>(current_.start_memory_size) / MB,
+ static_cast<double>(current_.end_object_size) / MB,
+ static_cast<double>(current_.end_memory_size) / MB);
+
+ int external_time = static_cast<int>(current_.scopes[Scope::EXTERNAL]);
+ if (external_time > 0) PrintF("%d / ", external_time);
+
+ double duration = current_.end_time - current_.start_time;
+ PrintF("%.1f ms", duration);
+ if (current_.type == Event::SCAVENGER) {
+ if (current_.incremental_marking_steps > 0) {
+ PrintF(" (+ %.1f ms in %d steps since last GC)",
+ current_.incremental_marking_duration,
+ current_.incremental_marking_steps);
+ }
+ } else {
+ if (current_.incremental_marking_steps > 0) {
+ PrintF(
+ " (+ %.1f ms in %d steps since start of marking, "
+ "biggest step %.1f ms)",
+ current_.incremental_marking_duration,
+ current_.incremental_marking_steps,
+ current_.longest_incremental_marking_step);
+ }
+ }
+
+ if (current_.gc_reason != NULL) {
+ PrintF(" [%s]", current_.gc_reason);
+ }
+
+ if (current_.collector_reason != NULL) {
+ PrintF(" [%s]", current_.collector_reason);
+ }
+
+ PrintF(".\n");
+}
+
+
+void GCTracer::PrintNVP() const {
+ PrintPID("%8.0f ms: ", heap_->isolate()->time_millis_since_init());
+
+ double duration = current_.end_time - current_.start_time;
+ double spent_in_mutator = current_.start_time - previous_.end_time;
+
+ PrintF("pause=%.1f ", duration);
+ PrintF("mutator=%.1f ", spent_in_mutator);
+ PrintF("gc=%s ", current_.TypeName(true));
+
+ PrintF("external=%.1f ", current_.scopes[Scope::EXTERNAL]);
+ PrintF("mark=%.1f ", current_.scopes[Scope::MC_MARK]);
+ PrintF("sweep=%.2f ", current_.scopes[Scope::MC_SWEEP]);
+ PrintF("sweepns=%.2f ", current_.scopes[Scope::MC_SWEEP_NEWSPACE]);
+ PrintF("sweepos=%.2f ", current_.scopes[Scope::MC_SWEEP_OLDSPACE]);
+ PrintF("sweepcode=%.2f ", current_.scopes[Scope::MC_SWEEP_CODE]);
+ PrintF("sweepcell=%.2f ", current_.scopes[Scope::MC_SWEEP_CELL]);
+ PrintF("sweepmap=%.2f ", current_.scopes[Scope::MC_SWEEP_MAP]);
+ PrintF("evacuate=%.1f ", current_.scopes[Scope::MC_EVACUATE_PAGES]);
+ PrintF("new_new=%.1f ",
+ current_.scopes[Scope::MC_UPDATE_NEW_TO_NEW_POINTERS]);
+ PrintF("root_new=%.1f ",
+ current_.scopes[Scope::MC_UPDATE_ROOT_TO_NEW_POINTERS]);
+ PrintF("old_new=%.1f ",
+ current_.scopes[Scope::MC_UPDATE_OLD_TO_NEW_POINTERS]);
+ PrintF("compaction_ptrs=%.1f ",
+ current_.scopes[Scope::MC_UPDATE_POINTERS_TO_EVACUATED]);
+ PrintF("intracompaction_ptrs=%.1f ",
+ current_.scopes[Scope::MC_UPDATE_POINTERS_BETWEEN_EVACUATED]);
+ PrintF("misc_compaction=%.1f ",
+ current_.scopes[Scope::MC_UPDATE_MISC_POINTERS]);
+ PrintF("weakcollection_process=%.1f ",
+ current_.scopes[Scope::MC_WEAKCOLLECTION_PROCESS]);
+ PrintF("weakcollection_clear=%.1f ",
+ current_.scopes[Scope::MC_WEAKCOLLECTION_CLEAR]);
+ PrintF("weakcollection_abort=%.1f ",
+ current_.scopes[Scope::MC_WEAKCOLLECTION_ABORT]);
+
+ PrintF("total_size_before=%" V8_PTR_PREFIX "d ", current_.start_object_size);
+ PrintF("total_size_after=%" V8_PTR_PREFIX "d ", current_.end_object_size);
+ PrintF("holes_size_before=%" V8_PTR_PREFIX "d ", current_.start_holes_size);
+ PrintF("holes_size_after=%" V8_PTR_PREFIX "d ", current_.end_holes_size);
+
+ intptr_t allocated_since_last_gc =
+ current_.start_object_size - previous_.end_object_size;
+ PrintF("allocated=%" V8_PTR_PREFIX "d ", allocated_since_last_gc);
+ PrintF("promoted=%" V8_PTR_PREFIX "d ", heap_->promoted_objects_size_);
+ PrintF("semi_space_copied=%" V8_PTR_PREFIX "d ",
+ heap_->semi_space_copied_object_size_);
+ PrintF("nodes_died_in_new=%d ", heap_->nodes_died_in_new_space_);
+ PrintF("nodes_copied_in_new=%d ", heap_->nodes_copied_in_new_space_);
+ PrintF("nodes_promoted=%d ", heap_->nodes_promoted_);
+ PrintF("promotion_rate=%.1f%% ", heap_->promotion_rate_);
+ PrintF("semi_space_copy_rate=%.1f%% ", heap_->semi_space_copied_rate_);
+ PrintF("new_space_allocation_throughput=%" V8_PTR_PREFIX "d ",
+ NewSpaceAllocationThroughputInBytesPerMillisecond());
+
+ if (current_.type == Event::SCAVENGER) {
+ PrintF("steps_count=%d ", current_.incremental_marking_steps);
+ PrintF("steps_took=%.1f ", current_.incremental_marking_duration);
+ PrintF("scavenge_throughput=%" V8_PTR_PREFIX "d ",
+ ScavengeSpeedInBytesPerMillisecond());
+ } else {
+ PrintF("steps_count=%d ", current_.incremental_marking_steps);
+ PrintF("steps_took=%.1f ", current_.incremental_marking_duration);
+ PrintF("longest_step=%.1f ", current_.longest_incremental_marking_step);
+ PrintF("incremental_marking_throughput=%" V8_PTR_PREFIX "d ",
+ IncrementalMarkingSpeedInBytesPerMillisecond());
+ }
+
+ PrintF("\n");
+}
+
+
+double GCTracer::MeanDuration(const EventBuffer& events) const {
+ if (events.empty()) return 0.0;
+
+ double mean = 0.0;
+ EventBuffer::const_iterator iter = events.begin();
+ while (iter != events.end()) {
+ mean += iter->end_time - iter->start_time;
+ ++iter;
+ }
+
+ return mean / events.size();
+}
+
+
+double GCTracer::MaxDuration(const EventBuffer& events) const {
+ if (events.empty()) return 0.0;
+
+ double maximum = 0.0f;
+ EventBuffer::const_iterator iter = events.begin();
+ while (iter != events.end()) {
+ maximum = Max(iter->end_time - iter->start_time, maximum);
+ ++iter;
+ }
+
+ return maximum;
+}
+
+
+double GCTracer::MeanIncrementalMarkingDuration() const {
+ if (cumulative_incremental_marking_steps_ == 0) return 0.0;
+
+ // We haven't completed an entire round of incremental marking, yet.
+ // Use data from GCTracer instead of data from event buffers.
+ if (mark_compactor_events_.empty()) {
+ return cumulative_incremental_marking_duration_ /
+ cumulative_incremental_marking_steps_;
+ }
+
+ int steps = 0;
+ double durations = 0.0;
+ EventBuffer::const_iterator iter = mark_compactor_events_.begin();
+ while (iter != mark_compactor_events_.end()) {
+ steps += iter->incremental_marking_steps;
+ durations += iter->incremental_marking_duration;
+ ++iter;
+ }
+
+ if (steps == 0) return 0.0;
+
+ return durations / steps;
+}
+
+
+double GCTracer::MaxIncrementalMarkingDuration() const {
+ // We haven't completed an entire round of incremental marking, yet.
+ // Use data from GCTracer instead of data from event buffers.
+ if (mark_compactor_events_.empty()) return longest_incremental_marking_step_;
+
+ double max_duration = 0.0;
+ EventBuffer::const_iterator iter = mark_compactor_events_.begin();
+ while (iter != mark_compactor_events_.end())
+ max_duration = Max(iter->longest_incremental_marking_step, max_duration);
+
+ return max_duration;
+}
+
+
+intptr_t GCTracer::IncrementalMarkingSpeedInBytesPerMillisecond() const {
+ if (cumulative_incremental_marking_duration_ == 0.0) return 0;
+
+ // We haven't completed an entire round of incremental marking, yet.
+ // Use data from GCTracer instead of data from event buffers.
+ if (mark_compactor_events_.empty()) {
+ return static_cast<intptr_t>(cumulative_incremental_marking_bytes_ /
+ cumulative_pure_incremental_marking_duration_);
+ }
+
+ intptr_t bytes = 0;
+ double durations = 0.0;
+ EventBuffer::const_iterator iter = mark_compactor_events_.begin();
+ while (iter != mark_compactor_events_.end()) {
+ bytes += iter->incremental_marking_bytes;
+ durations += iter->pure_incremental_marking_duration;
+ ++iter;
+ }
+
+ if (durations == 0.0) return 0;
+
+ return static_cast<intptr_t>(bytes / durations);
+}
+
+
+intptr_t GCTracer::ScavengeSpeedInBytesPerMillisecond() const {
+ intptr_t bytes = 0;
+ double durations = 0.0;
+ EventBuffer::const_iterator iter = scavenger_events_.begin();
+ while (iter != scavenger_events_.end()) {
+ bytes += iter->new_space_object_size;
+ durations += iter->end_time - iter->start_time;
+ ++iter;
+ }
+
+ if (durations == 0.0) return 0;
+
+ return static_cast<intptr_t>(bytes / durations);
+}
+
+
+intptr_t GCTracer::MarkCompactSpeedInBytesPerMillisecond() const {
+ intptr_t bytes = 0;
+ double durations = 0.0;
+ EventBuffer::const_iterator iter = mark_compactor_events_.begin();
+ while (iter != mark_compactor_events_.end()) {
+ bytes += iter->start_object_size;
+ durations += iter->end_time - iter->start_time +
+ iter->pure_incremental_marking_duration;
+ ++iter;
+ }
+
+ if (durations == 0.0) return 0;
+
+ return static_cast<intptr_t>(bytes / durations);
+}
+
+
+intptr_t GCTracer::NewSpaceAllocationThroughputInBytesPerMillisecond() const {
+ intptr_t bytes = 0;
+ double durations = 0.0;
+ AllocationEventBuffer::const_iterator iter = allocation_events_.begin();
+ while (iter != allocation_events_.end()) {
+ bytes += iter->allocation_in_bytes_;
+ durations += iter->duration_;
+ ++iter;
+ }
+
+ if (durations == 0.0) return 0;
+
+ return static_cast<intptr_t>(bytes / durations);
+}
+}
+} // namespace v8::internal
diff --git a/src/heap/gc-tracer.h b/src/heap/gc-tracer.h
new file mode 100644
index 0000000..4e70f07
--- /dev/null
+++ b/src/heap/gc-tracer.h
@@ -0,0 +1,401 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_GC_TRACER_H_
+#define V8_HEAP_GC_TRACER_H_
+
+#include "src/base/platform/platform.h"
+
+namespace v8 {
+namespace internal {
+
+// A simple ring buffer class with maximum size known at compile time.
+// The class only implements the functionality required in GCTracer.
+template <typename T, size_t MAX_SIZE>
+class RingBuffer {
+ public:
+ class const_iterator {
+ public:
+ const_iterator() : index_(0), elements_(NULL) {}
+
+ const_iterator(size_t index, const T* elements)
+ : index_(index), elements_(elements) {}
+
+ bool operator==(const const_iterator& rhs) const {
+ return elements_ == rhs.elements_ && index_ == rhs.index_;
+ }
+
+ bool operator!=(const const_iterator& rhs) const {
+ return elements_ != rhs.elements_ || index_ != rhs.index_;
+ }
+
+ operator const T*() const { return elements_ + index_; }
+
+ const T* operator->() const { return elements_ + index_; }
+
+ const T& operator*() const { return elements_[index_]; }
+
+ const_iterator& operator++() {
+ index_ = (index_ + 1) % (MAX_SIZE + 1);
+ return *this;
+ }
+
+ const_iterator& operator--() {
+ index_ = (index_ + MAX_SIZE) % (MAX_SIZE + 1);
+ return *this;
+ }
+
+ private:
+ size_t index_;
+ const T* elements_;
+ };
+
+ RingBuffer() : begin_(0), end_(0) {}
+
+ bool empty() const { return begin_ == end_; }
+ size_t size() const {
+ return (end_ - begin_ + MAX_SIZE + 1) % (MAX_SIZE + 1);
+ }
+ const_iterator begin() const { return const_iterator(begin_, elements_); }
+ const_iterator end() const { return const_iterator(end_, elements_); }
+ const_iterator back() const { return --end(); }
+ void push_back(const T& element) {
+ elements_[end_] = element;
+ end_ = (end_ + 1) % (MAX_SIZE + 1);
+ if (end_ == begin_) begin_ = (begin_ + 1) % (MAX_SIZE + 1);
+ }
+ void push_front(const T& element) {
+ begin_ = (begin_ + MAX_SIZE) % (MAX_SIZE + 1);
+ if (begin_ == end_) end_ = (end_ + MAX_SIZE) % (MAX_SIZE + 1);
+ elements_[begin_] = element;
+ }
+
+ private:
+ T elements_[MAX_SIZE + 1];
+ size_t begin_;
+ size_t end_;
+
+ DISALLOW_COPY_AND_ASSIGN(RingBuffer);
+};
+
+
+// GCTracer collects and prints ONE line after each garbage collector
+// invocation IFF --trace_gc is used.
+// TODO(ernstm): Unit tests.
+class GCTracer {
+ public:
+ class Scope {
+ public:
+ enum ScopeId {
+ EXTERNAL,
+ MC_MARK,
+ MC_SWEEP,
+ MC_SWEEP_NEWSPACE,
+ MC_SWEEP_OLDSPACE,
+ MC_SWEEP_CODE,
+ MC_SWEEP_CELL,
+ MC_SWEEP_MAP,
+ MC_EVACUATE_PAGES,
+ MC_UPDATE_NEW_TO_NEW_POINTERS,
+ MC_UPDATE_ROOT_TO_NEW_POINTERS,
+ MC_UPDATE_OLD_TO_NEW_POINTERS,
+ MC_UPDATE_POINTERS_TO_EVACUATED,
+ MC_UPDATE_POINTERS_BETWEEN_EVACUATED,
+ MC_UPDATE_MISC_POINTERS,
+ MC_WEAKCOLLECTION_PROCESS,
+ MC_WEAKCOLLECTION_CLEAR,
+ MC_WEAKCOLLECTION_ABORT,
+ MC_FLUSH_CODE,
+ NUMBER_OF_SCOPES
+ };
+
+ Scope(GCTracer* tracer, ScopeId scope) : tracer_(tracer), scope_(scope) {
+ start_time_ = base::OS::TimeCurrentMillis();
+ }
+
+ ~Scope() {
+ DCHECK(scope_ < NUMBER_OF_SCOPES); // scope_ is unsigned.
+ tracer_->current_.scopes[scope_] +=
+ base::OS::TimeCurrentMillis() - start_time_;
+ }
+
+ private:
+ GCTracer* tracer_;
+ ScopeId scope_;
+ double start_time_;
+
+ DISALLOW_COPY_AND_ASSIGN(Scope);
+ };
+
+
+ class AllocationEvent {
+ public:
+ // Default constructor leaves the event uninitialized.
+ AllocationEvent() {}
+
+ AllocationEvent(double duration, intptr_t allocation_in_bytes);
+
+ // Time spent in the mutator during the end of the last garbage collection
+ // to the beginning of the next garbage collection.
+ double duration_;
+
+ // Memory allocated in the new space during the end of the last garbage
+ // collection to the beginning of the next garbage collection.
+ intptr_t allocation_in_bytes_;
+ };
+
+ class Event {
+ public:
+ enum Type { SCAVENGER = 0, MARK_COMPACTOR = 1, START = 2 };
+
+ // Default constructor leaves the event uninitialized.
+ Event() {}
+
+ Event(Type type, const char* gc_reason, const char* collector_reason);
+
+ // Returns a string describing the event type.
+ const char* TypeName(bool short_name) const;
+
+ // Type of event
+ Type type;
+
+ const char* gc_reason;
+ const char* collector_reason;
+
+ // Timestamp set in the constructor.
+ double start_time;
+
+ // Timestamp set in the destructor.
+ double end_time;
+
+ // Size of objects in heap set in constructor.
+ intptr_t start_object_size;
+
+ // Size of objects in heap set in destructor.
+ intptr_t end_object_size;
+
+ // Size of memory allocated from OS set in constructor.
+ intptr_t start_memory_size;
+
+ // Size of memory allocated from OS set in destructor.
+ intptr_t end_memory_size;
+
+ // Total amount of space either wasted or contained in one of free lists
+ // before the current GC.
+ intptr_t start_holes_size;
+
+ // Total amount of space either wasted or contained in one of free lists
+ // after the current GC.
+ intptr_t end_holes_size;
+
+ // Size of new space objects in constructor.
+ intptr_t new_space_object_size;
+
+ // Number of incremental marking steps since creation of tracer.
+ // (value at start of event)
+ int cumulative_incremental_marking_steps;
+
+ // Incremental marking steps since
+ // - last event for SCAVENGER events
+ // - last MARK_COMPACTOR event for MARK_COMPACTOR events
+ int incremental_marking_steps;
+
+ // Bytes marked since creation of tracer (value at start of event).
+ intptr_t cumulative_incremental_marking_bytes;
+
+ // Bytes marked since
+ // - last event for SCAVENGER events
+ // - last MARK_COMPACTOR event for MARK_COMPACTOR events
+ intptr_t incremental_marking_bytes;
+
+ // Cumulative duration of incremental marking steps since creation of
+ // tracer. (value at start of event)
+ double cumulative_incremental_marking_duration;
+
+ // Duration of incremental marking steps since
+ // - last event for SCAVENGER events
+ // - last MARK_COMPACTOR event for MARK_COMPACTOR events
+ double incremental_marking_duration;
+
+ // Cumulative pure duration of incremental marking steps since creation of
+ // tracer. (value at start of event)
+ double cumulative_pure_incremental_marking_duration;
+
+ // Duration of pure incremental marking steps since
+ // - last event for SCAVENGER events
+ // - last MARK_COMPACTOR event for MARK_COMPACTOR events
+ double pure_incremental_marking_duration;
+
+ // Longest incremental marking step since start of marking.
+ // (value at start of event)
+ double longest_incremental_marking_step;
+
+ // Amounts of time spent in different scopes during GC.
+ double scopes[Scope::NUMBER_OF_SCOPES];
+ };
+
+ static const int kRingBufferMaxSize = 10;
+
+ typedef RingBuffer<Event, kRingBufferMaxSize> EventBuffer;
+
+ typedef RingBuffer<AllocationEvent, kRingBufferMaxSize> AllocationEventBuffer;
+
+ explicit GCTracer(Heap* heap);
+
+ // Start collecting data.
+ void Start(GarbageCollector collector, const char* gc_reason,
+ const char* collector_reason);
+
+ // Stop collecting data and print results.
+ void Stop();
+
+ // Log an allocation throughput event.
+ void AddNewSpaceAllocationTime(double duration, intptr_t allocation_in_bytes);
+
+ // Log an incremental marking step.
+ void AddIncrementalMarkingStep(double duration, intptr_t bytes);
+
+ // Log time spent in marking.
+ void AddMarkingTime(double duration) {
+ cumulative_marking_duration_ += duration;
+ }
+
+ // Time spent in marking.
+ double cumulative_marking_duration() const {
+ return cumulative_marking_duration_;
+ }
+
+ // Log time spent in sweeping on main thread.
+ void AddSweepingTime(double duration) {
+ cumulative_sweeping_duration_ += duration;
+ }
+
+ // Time spent in sweeping on main thread.
+ double cumulative_sweeping_duration() const {
+ return cumulative_sweeping_duration_;
+ }
+
+ // Compute the mean duration of the last scavenger events. Returns 0 if no
+ // events have been recorded.
+ double MeanScavengerDuration() const {
+ return MeanDuration(scavenger_events_);
+ }
+
+ // Compute the max duration of the last scavenger events. Returns 0 if no
+ // events have been recorded.
+ double MaxScavengerDuration() const { return MaxDuration(scavenger_events_); }
+
+ // Compute the mean duration of the last mark compactor events. Returns 0 if
+ // no events have been recorded.
+ double MeanMarkCompactorDuration() const {
+ return MeanDuration(mark_compactor_events_);
+ }
+
+ // Compute the max duration of the last mark compactor events. Return 0 if no
+ // events have been recorded.
+ double MaxMarkCompactorDuration() const {
+ return MaxDuration(mark_compactor_events_);
+ }
+
+ // Compute the mean step duration of the last incremental marking round.
+ // Returns 0 if no incremental marking round has been completed.
+ double MeanIncrementalMarkingDuration() const;
+
+ // Compute the max step duration of the last incremental marking round.
+ // Returns 0 if no incremental marking round has been completed.
+ double MaxIncrementalMarkingDuration() const;
+
+ // Compute the average incremental marking speed in bytes/millisecond.
+ // Returns 0 if no events have been recorded.
+ intptr_t IncrementalMarkingSpeedInBytesPerMillisecond() const;
+
+ // Compute the average scavenge speed in bytes/millisecond.
+ // Returns 0 if no events have been recorded.
+ intptr_t ScavengeSpeedInBytesPerMillisecond() const;
+
+ // Compute the max mark-sweep speed in bytes/millisecond.
+ // Returns 0 if no events have been recorded.
+ intptr_t MarkCompactSpeedInBytesPerMillisecond() const;
+
+ // Allocation throughput in the new space in bytes/millisecond.
+ // Returns 0 if no events have been recorded.
+ intptr_t NewSpaceAllocationThroughputInBytesPerMillisecond() const;
+
+ private:
+ // Print one detailed trace line in name=value format.
+ // TODO(ernstm): Move to Heap.
+ void PrintNVP() const;
+
+ // Print one trace line.
+ // TODO(ernstm): Move to Heap.
+ void Print() const;
+
+ // Compute the mean duration of the events in the given ring buffer.
+ double MeanDuration(const EventBuffer& events) const;
+
+ // Compute the max duration of the events in the given ring buffer.
+ double MaxDuration(const EventBuffer& events) const;
+
+ // Pointer to the heap that owns this tracer.
+ Heap* heap_;
+
+ // Current tracer event. Populated during Start/Stop cycle. Valid after Stop()
+ // has returned.
+ Event current_;
+
+ // Previous tracer event.
+ Event previous_;
+
+ // Previous MARK_COMPACTOR event.
+ Event previous_mark_compactor_event_;
+
+ // RingBuffers for SCAVENGER events.
+ EventBuffer scavenger_events_;
+
+ // RingBuffers for MARK_COMPACTOR events.
+ EventBuffer mark_compactor_events_;
+
+ // RingBuffer for allocation events.
+ AllocationEventBuffer allocation_events_;
+
+ // Cumulative number of incremental marking steps since creation of tracer.
+ int cumulative_incremental_marking_steps_;
+
+ // Cumulative size of incremental marking steps (in bytes) since creation of
+ // tracer.
+ intptr_t cumulative_incremental_marking_bytes_;
+
+ // Cumulative duration of incremental marking steps since creation of tracer.
+ double cumulative_incremental_marking_duration_;
+
+ // Cumulative duration of pure incremental marking steps since creation of
+ // tracer.
+ double cumulative_pure_incremental_marking_duration_;
+
+ // Longest incremental marking step since start of marking.
+ double longest_incremental_marking_step_;
+
+ // Total marking time.
+ // This timer is precise when run with --print-cumulative-gc-stat
+ double cumulative_marking_duration_;
+
+ // Total sweeping time on the main thread.
+ // This timer is precise when run with --print-cumulative-gc-stat
+ // TODO(hpayer): Account for sweeping time on sweeper threads. Add a
+ // different field for that.
+ // TODO(hpayer): This timer right now just holds the sweeping time
+ // of the initial atomic sweeping pause. Make sure that it accumulates
+ // all sweeping operations performed on the main thread.
+ double cumulative_sweeping_duration_;
+
+ // Holds the new space top pointer recorded at the end of the last garbage
+ // collection.
+ intptr_t new_space_top_after_gc_;
+
+ DISALLOW_COPY_AND_ASSIGN(GCTracer);
+};
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_GC_TRACER_H_
diff --git a/src/heap/heap-inl.h b/src/heap/heap-inl.h
new file mode 100644
index 0000000..e658224
--- /dev/null
+++ b/src/heap/heap-inl.h
@@ -0,0 +1,780 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_HEAP_INL_H_
+#define V8_HEAP_HEAP_INL_H_
+
+#include <cmath>
+
+#include "src/base/platform/platform.h"
+#include "src/cpu-profiler.h"
+#include "src/heap/heap.h"
+#include "src/heap/store-buffer.h"
+#include "src/heap/store-buffer-inl.h"
+#include "src/heap-profiler.h"
+#include "src/isolate.h"
+#include "src/list-inl.h"
+#include "src/msan.h"
+#include "src/objects.h"
+
+namespace v8 {
+namespace internal {
+
+void PromotionQueue::insert(HeapObject* target, int size) {
+ if (emergency_stack_ != NULL) {
+ emergency_stack_->Add(Entry(target, size));
+ return;
+ }
+
+ if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(rear_))) {
+ NewSpacePage* rear_page =
+ NewSpacePage::FromAddress(reinterpret_cast<Address>(rear_));
+ DCHECK(!rear_page->prev_page()->is_anchor());
+ rear_ = reinterpret_cast<intptr_t*>(rear_page->prev_page()->area_end());
+ }
+
+ if ((rear_ - 2) < limit_) {
+ RelocateQueueHead();
+ emergency_stack_->Add(Entry(target, size));
+ return;
+ }
+
+ *(--rear_) = reinterpret_cast<intptr_t>(target);
+ *(--rear_) = size;
+// Assert no overflow into live objects.
+#ifdef DEBUG
+ SemiSpace::AssertValidRange(target->GetIsolate()->heap()->new_space()->top(),
+ reinterpret_cast<Address>(rear_));
+#endif
+}
+
+
+template <>
+bool inline Heap::IsOneByte(Vector<const char> str, int chars) {
+ // TODO(dcarney): incorporate Latin-1 check when Latin-1 is supported?
+ return chars == str.length();
+}
+
+
+template <>
+bool inline Heap::IsOneByte(String* str, int chars) {
+ return str->IsOneByteRepresentation();
+}
+
+
+AllocationResult Heap::AllocateInternalizedStringFromUtf8(
+ Vector<const char> str, int chars, uint32_t hash_field) {
+ if (IsOneByte(str, chars)) {
+ return AllocateOneByteInternalizedString(Vector<const uint8_t>::cast(str),
+ hash_field);
+ }
+ return AllocateInternalizedStringImpl<false>(str, chars, hash_field);
+}
+
+
+template <typename T>
+AllocationResult Heap::AllocateInternalizedStringImpl(T t, int chars,
+ uint32_t hash_field) {
+ if (IsOneByte(t, chars)) {
+ return AllocateInternalizedStringImpl<true>(t, chars, hash_field);
+ }
+ return AllocateInternalizedStringImpl<false>(t, chars, hash_field);
+}
+
+
+AllocationResult Heap::AllocateOneByteInternalizedString(
+ Vector<const uint8_t> str, uint32_t hash_field) {
+ CHECK_GE(String::kMaxLength, str.length());
+ // Compute map and object size.
+ Map* map = one_byte_internalized_string_map();
+ int size = SeqOneByteString::SizeFor(str.length());
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, TENURED);
+
+ // Allocate string.
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ // String maps are all immortal immovable objects.
+ result->set_map_no_write_barrier(map);
+ // Set length and hash fields of the allocated string.
+ String* answer = String::cast(result);
+ answer->set_length(str.length());
+ answer->set_hash_field(hash_field);
+
+ DCHECK_EQ(size, answer->Size());
+
+ // Fill in the characters.
+ MemCopy(answer->address() + SeqOneByteString::kHeaderSize, str.start(),
+ str.length());
+
+ return answer;
+}
+
+
+AllocationResult Heap::AllocateTwoByteInternalizedString(Vector<const uc16> str,
+ uint32_t hash_field) {
+ CHECK_GE(String::kMaxLength, str.length());
+ // Compute map and object size.
+ Map* map = internalized_string_map();
+ int size = SeqTwoByteString::SizeFor(str.length());
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, TENURED);
+
+ // Allocate string.
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ result->set_map(map);
+ // Set length and hash fields of the allocated string.
+ String* answer = String::cast(result);
+ answer->set_length(str.length());
+ answer->set_hash_field(hash_field);
+
+ DCHECK_EQ(size, answer->Size());
+
+ // Fill in the characters.
+ MemCopy(answer->address() + SeqTwoByteString::kHeaderSize, str.start(),
+ str.length() * kUC16Size);
+
+ return answer;
+}
+
+AllocationResult Heap::CopyFixedArray(FixedArray* src) {
+ if (src->length() == 0) return src;
+ return CopyFixedArrayWithMap(src, src->map());
+}
+
+
+AllocationResult Heap::CopyFixedDoubleArray(FixedDoubleArray* src) {
+ if (src->length() == 0) return src;
+ return CopyFixedDoubleArrayWithMap(src, src->map());
+}
+
+
+AllocationResult Heap::CopyConstantPoolArray(ConstantPoolArray* src) {
+ if (src->length() == 0) return src;
+ return CopyConstantPoolArrayWithMap(src, src->map());
+}
+
+
+AllocationResult Heap::AllocateRaw(int size_in_bytes, AllocationSpace space,
+ AllocationSpace retry_space) {
+ DCHECK(AllowHandleAllocation::IsAllowed());
+ DCHECK(AllowHeapAllocation::IsAllowed());
+ DCHECK(gc_state_ == NOT_IN_GC);
+#ifdef DEBUG
+ if (FLAG_gc_interval >= 0 && AllowAllocationFailure::IsAllowed(isolate_) &&
+ Heap::allocation_timeout_-- <= 0) {
+ return AllocationResult::Retry(space);
+ }
+ isolate_->counters()->objs_since_last_full()->Increment();
+ isolate_->counters()->objs_since_last_young()->Increment();
+#endif
+
+ HeapObject* object;
+ AllocationResult allocation;
+ if (NEW_SPACE == space) {
+ allocation = new_space_.AllocateRaw(size_in_bytes);
+ if (always_allocate() && allocation.IsRetry() && retry_space != NEW_SPACE) {
+ space = retry_space;
+ } else {
+ if (allocation.To(&object)) {
+ OnAllocationEvent(object, size_in_bytes);
+ }
+ return allocation;
+ }
+ }
+
+ if (OLD_POINTER_SPACE == space) {
+ allocation = old_pointer_space_->AllocateRaw(size_in_bytes);
+ } else if (OLD_DATA_SPACE == space) {
+ allocation = old_data_space_->AllocateRaw(size_in_bytes);
+ } else if (CODE_SPACE == space) {
+ if (size_in_bytes <= code_space()->AreaSize()) {
+ allocation = code_space_->AllocateRaw(size_in_bytes);
+ } else {
+ // Large code objects are allocated in large object space.
+ allocation = lo_space_->AllocateRaw(size_in_bytes, EXECUTABLE);
+ }
+ } else if (LO_SPACE == space) {
+ allocation = lo_space_->AllocateRaw(size_in_bytes, NOT_EXECUTABLE);
+ } else if (CELL_SPACE == space) {
+ allocation = cell_space_->AllocateRaw(size_in_bytes);
+ } else if (PROPERTY_CELL_SPACE == space) {
+ allocation = property_cell_space_->AllocateRaw(size_in_bytes);
+ } else {
+ DCHECK(MAP_SPACE == space);
+ allocation = map_space_->AllocateRaw(size_in_bytes);
+ }
+ if (allocation.To(&object)) {
+ OnAllocationEvent(object, size_in_bytes);
+ } else {
+ old_gen_exhausted_ = true;
+ }
+ return allocation;
+}
+
+
+void Heap::OnAllocationEvent(HeapObject* object, int size_in_bytes) {
+ HeapProfiler* profiler = isolate_->heap_profiler();
+ if (profiler->is_tracking_allocations()) {
+ profiler->AllocationEvent(object->address(), size_in_bytes);
+ }
+
+ if (FLAG_verify_predictable) {
+ ++allocations_count_;
+
+ UpdateAllocationsHash(object);
+ UpdateAllocationsHash(size_in_bytes);
+
+ if ((FLAG_dump_allocations_digest_at_alloc > 0) &&
+ (--dump_allocations_hash_countdown_ == 0)) {
+ dump_allocations_hash_countdown_ = FLAG_dump_allocations_digest_at_alloc;
+ PrintAlloctionsHash();
+ }
+ }
+}
+
+
+void Heap::OnMoveEvent(HeapObject* target, HeapObject* source,
+ int size_in_bytes) {
+ HeapProfiler* heap_profiler = isolate_->heap_profiler();
+ if (heap_profiler->is_tracking_object_moves()) {
+ heap_profiler->ObjectMoveEvent(source->address(), target->address(),
+ size_in_bytes);
+ }
+
+ if (isolate_->logger()->is_logging_code_events() ||
+ isolate_->cpu_profiler()->is_profiling()) {
+ if (target->IsSharedFunctionInfo()) {
+ PROFILE(isolate_, SharedFunctionInfoMoveEvent(source->address(),
+ target->address()));
+ }
+ }
+
+ if (FLAG_verify_predictable) {
+ ++allocations_count_;
+
+ UpdateAllocationsHash(source);
+ UpdateAllocationsHash(target);
+ UpdateAllocationsHash(size_in_bytes);
+
+ if ((FLAG_dump_allocations_digest_at_alloc > 0) &&
+ (--dump_allocations_hash_countdown_ == 0)) {
+ dump_allocations_hash_countdown_ = FLAG_dump_allocations_digest_at_alloc;
+ PrintAlloctionsHash();
+ }
+ }
+}
+
+
+void Heap::UpdateAllocationsHash(HeapObject* object) {
+ Address object_address = object->address();
+ MemoryChunk* memory_chunk = MemoryChunk::FromAddress(object_address);
+ AllocationSpace allocation_space = memory_chunk->owner()->identity();
+
+ STATIC_ASSERT(kSpaceTagSize + kPageSizeBits <= 32);
+ uint32_t value =
+ static_cast<uint32_t>(object_address - memory_chunk->address()) |
+ (static_cast<uint32_t>(allocation_space) << kPageSizeBits);
+
+ UpdateAllocationsHash(value);
+}
+
+
+void Heap::UpdateAllocationsHash(uint32_t value) {
+ uint16_t c1 = static_cast<uint16_t>(value);
+ uint16_t c2 = static_cast<uint16_t>(value >> 16);
+ raw_allocations_hash_ =
+ StringHasher::AddCharacterCore(raw_allocations_hash_, c1);
+ raw_allocations_hash_ =
+ StringHasher::AddCharacterCore(raw_allocations_hash_, c2);
+}
+
+
+void Heap::PrintAlloctionsHash() {
+ uint32_t hash = StringHasher::GetHashCore(raw_allocations_hash_);
+ PrintF("\n### Allocations = %u, hash = 0x%08x\n", allocations_count_, hash);
+}
+
+
+void Heap::FinalizeExternalString(String* string) {
+ DCHECK(string->IsExternalString());
+ v8::String::ExternalStringResourceBase** resource_addr =
+ reinterpret_cast<v8::String::ExternalStringResourceBase**>(
+ reinterpret_cast<byte*>(string) + ExternalString::kResourceOffset -
+ kHeapObjectTag);
+
+ // Dispose of the C++ object if it has not already been disposed.
+ if (*resource_addr != NULL) {
+ (*resource_addr)->Dispose();
+ *resource_addr = NULL;
+ }
+}
+
+
+bool Heap::InNewSpace(Object* object) {
+ bool result = new_space_.Contains(object);
+ DCHECK(!result || // Either not in new space
+ gc_state_ != NOT_IN_GC || // ... or in the middle of GC
+ InToSpace(object)); // ... or in to-space (where we allocate).
+ return result;
+}
+
+
+bool Heap::InNewSpace(Address address) { return new_space_.Contains(address); }
+
+
+bool Heap::InFromSpace(Object* object) {
+ return new_space_.FromSpaceContains(object);
+}
+
+
+bool Heap::InToSpace(Object* object) {
+ return new_space_.ToSpaceContains(object);
+}
+
+
+bool Heap::InOldPointerSpace(Address address) {
+ return old_pointer_space_->Contains(address);
+}
+
+
+bool Heap::InOldPointerSpace(Object* object) {
+ return InOldPointerSpace(reinterpret_cast<Address>(object));
+}
+
+
+bool Heap::InOldDataSpace(Address address) {
+ return old_data_space_->Contains(address);
+}
+
+
+bool Heap::InOldDataSpace(Object* object) {
+ return InOldDataSpace(reinterpret_cast<Address>(object));
+}
+
+
+bool Heap::OldGenerationAllocationLimitReached() {
+ if (!incremental_marking()->IsStopped()) return false;
+ return OldGenerationSpaceAvailable() < 0;
+}
+
+
+bool Heap::ShouldBePromoted(Address old_address, int object_size) {
+ NewSpacePage* page = NewSpacePage::FromAddress(old_address);
+ Address age_mark = new_space_.age_mark();
+ return page->IsFlagSet(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK) &&
+ (!page->ContainsLimit(age_mark) || old_address < age_mark);
+}
+
+
+void Heap::RecordWrite(Address address, int offset) {
+ if (!InNewSpace(address)) store_buffer_.Mark(address + offset);
+}
+
+
+void Heap::RecordWrites(Address address, int start, int len) {
+ if (!InNewSpace(address)) {
+ for (int i = 0; i < len; i++) {
+ store_buffer_.Mark(address + start + i * kPointerSize);
+ }
+ }
+}
+
+
+OldSpace* Heap::TargetSpace(HeapObject* object) {
+ InstanceType type = object->map()->instance_type();
+ AllocationSpace space = TargetSpaceId(type);
+ return (space == OLD_POINTER_SPACE) ? old_pointer_space_ : old_data_space_;
+}
+
+
+AllocationSpace Heap::TargetSpaceId(InstanceType type) {
+ // Heap numbers and sequential strings are promoted to old data space, all
+ // other object types are promoted to old pointer space. We do not use
+ // object->IsHeapNumber() and object->IsSeqString() because we already
+ // know that object has the heap object tag.
+
+ // These objects are never allocated in new space.
+ DCHECK(type != MAP_TYPE);
+ DCHECK(type != CODE_TYPE);
+ DCHECK(type != ODDBALL_TYPE);
+ DCHECK(type != CELL_TYPE);
+ DCHECK(type != PROPERTY_CELL_TYPE);
+
+ if (type <= LAST_NAME_TYPE) {
+ if (type == SYMBOL_TYPE) return OLD_POINTER_SPACE;
+ DCHECK(type < FIRST_NONSTRING_TYPE);
+ // There are four string representations: sequential strings, external
+ // strings, cons strings, and sliced strings.
+ // Only the latter two contain non-map-word pointers to heap objects.
+ return ((type & kIsIndirectStringMask) == kIsIndirectStringTag)
+ ? OLD_POINTER_SPACE
+ : OLD_DATA_SPACE;
+ } else {
+ return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
+ }
+}
+
+
+bool Heap::AllowedToBeMigrated(HeapObject* obj, AllocationSpace dst) {
+ // Object migration is governed by the following rules:
+ //
+ // 1) Objects in new-space can be migrated to one of the old spaces
+ // that matches their target space or they stay in new-space.
+ // 2) Objects in old-space stay in the same space when migrating.
+ // 3) Fillers (two or more words) can migrate due to left-trimming of
+ // fixed arrays in new-space, old-data-space and old-pointer-space.
+ // 4) Fillers (one word) can never migrate, they are skipped by
+ // incremental marking explicitly to prevent invalid pattern.
+ // 5) Short external strings can end up in old pointer space when a cons
+ // string in old pointer space is made external (String::MakeExternal).
+ //
+ // Since this function is used for debugging only, we do not place
+ // asserts here, but check everything explicitly.
+ if (obj->map() == one_pointer_filler_map()) return false;
+ InstanceType type = obj->map()->instance_type();
+ MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
+ AllocationSpace src = chunk->owner()->identity();
+ switch (src) {
+ case NEW_SPACE:
+ return dst == src || dst == TargetSpaceId(type);
+ case OLD_POINTER_SPACE:
+ return dst == src && (dst == TargetSpaceId(type) || obj->IsFiller() ||
+ obj->IsExternalString());
+ case OLD_DATA_SPACE:
+ return dst == src && dst == TargetSpaceId(type);
+ case CODE_SPACE:
+ return dst == src && type == CODE_TYPE;
+ case MAP_SPACE:
+ case CELL_SPACE:
+ case PROPERTY_CELL_SPACE:
+ case LO_SPACE:
+ return false;
+ case INVALID_SPACE:
+ break;
+ }
+ UNREACHABLE();
+ return false;
+}
+
+
+void Heap::CopyBlock(Address dst, Address src, int byte_size) {
+ CopyWords(reinterpret_cast<Object**>(dst), reinterpret_cast<Object**>(src),
+ static_cast<size_t>(byte_size / kPointerSize));
+}
+
+
+void Heap::MoveBlock(Address dst, Address src, int byte_size) {
+ DCHECK(IsAligned(byte_size, kPointerSize));
+
+ int size_in_words = byte_size / kPointerSize;
+
+ if ((dst < src) || (dst >= (src + byte_size))) {
+ Object** src_slot = reinterpret_cast<Object**>(src);
+ Object** dst_slot = reinterpret_cast<Object**>(dst);
+ Object** end_slot = src_slot + size_in_words;
+
+ while (src_slot != end_slot) {
+ *dst_slot++ = *src_slot++;
+ }
+ } else {
+ MemMove(dst, src, static_cast<size_t>(byte_size));
+ }
+}
+
+
+void Heap::ScavengePointer(HeapObject** p) { ScavengeObject(p, *p); }
+
+
+AllocationMemento* Heap::FindAllocationMemento(HeapObject* object) {
+ // Check if there is potentially a memento behind the object. If
+ // the last word of the memento is on another page we return
+ // immediately.
+ Address object_address = object->address();
+ Address memento_address = object_address + object->Size();
+ Address last_memento_word_address = memento_address + kPointerSize;
+ if (!NewSpacePage::OnSamePage(object_address, last_memento_word_address)) {
+ return NULL;
+ }
+
+ HeapObject* candidate = HeapObject::FromAddress(memento_address);
+ Map* candidate_map = candidate->map();
+ // This fast check may peek at an uninitialized word. However, the slow check
+ // below (memento_address == top) ensures that this is safe. Mark the word as
+ // initialized to silence MemorySanitizer warnings.
+ MSAN_MEMORY_IS_INITIALIZED(&candidate_map, sizeof(candidate_map));
+ if (candidate_map != allocation_memento_map()) return NULL;
+
+ // Either the object is the last object in the new space, or there is another
+ // object of at least word size (the header map word) following it, so
+ // suffices to compare ptr and top here. Note that technically we do not have
+ // to compare with the current top pointer of the from space page during GC,
+ // since we always install filler objects above the top pointer of a from
+ // space page when performing a garbage collection. However, always performing
+ // the test makes it possible to have a single, unified version of
+ // FindAllocationMemento that is used both by the GC and the mutator.
+ Address top = NewSpaceTop();
+ DCHECK(memento_address == top ||
+ memento_address + HeapObject::kHeaderSize <= top ||
+ !NewSpacePage::OnSamePage(memento_address, top));
+ if (memento_address == top) return NULL;
+
+ AllocationMemento* memento = AllocationMemento::cast(candidate);
+ if (!memento->IsValid()) return NULL;
+ return memento;
+}
+
+
+void Heap::UpdateAllocationSiteFeedback(HeapObject* object,
+ ScratchpadSlotMode mode) {
+ Heap* heap = object->GetHeap();
+ DCHECK(heap->InFromSpace(object));
+
+ if (!FLAG_allocation_site_pretenuring ||
+ !AllocationSite::CanTrack(object->map()->instance_type()))
+ return;
+
+ AllocationMemento* memento = heap->FindAllocationMemento(object);
+ if (memento == NULL) return;
+
+ if (memento->GetAllocationSite()->IncrementMementoFoundCount()) {
+ heap->AddAllocationSiteToScratchpad(memento->GetAllocationSite(), mode);
+ }
+}
+
+
+void Heap::ScavengeObject(HeapObject** p, HeapObject* object) {
+ DCHECK(object->GetIsolate()->heap()->InFromSpace(object));
+
+ // We use the first word (where the map pointer usually is) of a heap
+ // object to record the forwarding pointer. A forwarding pointer can
+ // point to an old space, the code space, or the to space of the new
+ // generation.
+ MapWord first_word = object->map_word();
+
+ // If the first word is a forwarding address, the object has already been
+ // copied.
+ if (first_word.IsForwardingAddress()) {
+ HeapObject* dest = first_word.ToForwardingAddress();
+ DCHECK(object->GetIsolate()->heap()->InFromSpace(*p));
+ *p = dest;
+ return;
+ }
+
+ UpdateAllocationSiteFeedback(object, IGNORE_SCRATCHPAD_SLOT);
+
+ // AllocationMementos are unrooted and shouldn't survive a scavenge
+ DCHECK(object->map() != object->GetHeap()->allocation_memento_map());
+ // Call the slow part of scavenge object.
+ return ScavengeObjectSlow(p, object);
+}
+
+
+bool Heap::CollectGarbage(AllocationSpace space, const char* gc_reason,
+ const v8::GCCallbackFlags callbackFlags) {
+ const char* collector_reason = NULL;
+ GarbageCollector collector = SelectGarbageCollector(space, &collector_reason);
+ return CollectGarbage(collector, gc_reason, collector_reason, callbackFlags);
+}
+
+
+Isolate* Heap::isolate() {
+ return reinterpret_cast<Isolate*>(
+ reinterpret_cast<intptr_t>(this) -
+ reinterpret_cast<size_t>(reinterpret_cast<Isolate*>(4)->heap()) + 4);
+}
+
+
+// Calls the FUNCTION_CALL function and retries it up to three times
+// to guarantee that any allocations performed during the call will
+// succeed if there's enough memory.
+
+// Warning: Do not use the identifiers __object__, __maybe_object__ or
+// __scope__ in a call to this macro.
+
+#define RETURN_OBJECT_UNLESS_RETRY(ISOLATE, RETURN_VALUE) \
+ if (__allocation__.To(&__object__)) { \
+ DCHECK(__object__ != (ISOLATE)->heap()->exception()); \
+ RETURN_VALUE; \
+ }
+
+#define CALL_AND_RETRY(ISOLATE, FUNCTION_CALL, RETURN_VALUE, RETURN_EMPTY) \
+ do { \
+ AllocationResult __allocation__ = FUNCTION_CALL; \
+ Object* __object__ = NULL; \
+ RETURN_OBJECT_UNLESS_RETRY(ISOLATE, RETURN_VALUE) \
+ (ISOLATE)->heap()->CollectGarbage(__allocation__.RetrySpace(), \
+ "allocation failure"); \
+ __allocation__ = FUNCTION_CALL; \
+ RETURN_OBJECT_UNLESS_RETRY(ISOLATE, RETURN_VALUE) \
+ (ISOLATE)->counters()->gc_last_resort_from_handles()->Increment(); \
+ (ISOLATE)->heap()->CollectAllAvailableGarbage("last resort gc"); \
+ { \
+ AlwaysAllocateScope __scope__(ISOLATE); \
+ __allocation__ = FUNCTION_CALL; \
+ } \
+ RETURN_OBJECT_UNLESS_RETRY(ISOLATE, RETURN_VALUE) \
+ /* TODO(1181417): Fix this. */ \
+ v8::internal::Heap::FatalProcessOutOfMemory("CALL_AND_RETRY_LAST", true); \
+ RETURN_EMPTY; \
+ } while (false)
+
+#define CALL_AND_RETRY_OR_DIE(ISOLATE, FUNCTION_CALL, RETURN_VALUE, \
+ RETURN_EMPTY) \
+ CALL_AND_RETRY(ISOLATE, FUNCTION_CALL, RETURN_VALUE, RETURN_EMPTY)
+
+#define CALL_HEAP_FUNCTION(ISOLATE, FUNCTION_CALL, TYPE) \
+ CALL_AND_RETRY_OR_DIE(ISOLATE, FUNCTION_CALL, \
+ return Handle<TYPE>(TYPE::cast(__object__), ISOLATE), \
+ return Handle<TYPE>())
+
+
+#define CALL_HEAP_FUNCTION_VOID(ISOLATE, FUNCTION_CALL) \
+ CALL_AND_RETRY_OR_DIE(ISOLATE, FUNCTION_CALL, return, return)
+
+
+void ExternalStringTable::AddString(String* string) {
+ DCHECK(string->IsExternalString());
+ if (heap_->InNewSpace(string)) {
+ new_space_strings_.Add(string);
+ } else {
+ old_space_strings_.Add(string);
+ }
+}
+
+
+void ExternalStringTable::Iterate(ObjectVisitor* v) {
+ if (!new_space_strings_.is_empty()) {
+ Object** start = &new_space_strings_[0];
+ v->VisitPointers(start, start + new_space_strings_.length());
+ }
+ if (!old_space_strings_.is_empty()) {
+ Object** start = &old_space_strings_[0];
+ v->VisitPointers(start, start + old_space_strings_.length());
+ }
+}
+
+
+// Verify() is inline to avoid ifdef-s around its calls in release
+// mode.
+void ExternalStringTable::Verify() {
+#ifdef DEBUG
+ for (int i = 0; i < new_space_strings_.length(); ++i) {
+ Object* obj = Object::cast(new_space_strings_[i]);
+ DCHECK(heap_->InNewSpace(obj));
+ DCHECK(obj != heap_->the_hole_value());
+ }
+ for (int i = 0; i < old_space_strings_.length(); ++i) {
+ Object* obj = Object::cast(old_space_strings_[i]);
+ DCHECK(!heap_->InNewSpace(obj));
+ DCHECK(obj != heap_->the_hole_value());
+ }
+#endif
+}
+
+
+void ExternalStringTable::AddOldString(String* string) {
+ DCHECK(string->IsExternalString());
+ DCHECK(!heap_->InNewSpace(string));
+ old_space_strings_.Add(string);
+}
+
+
+void ExternalStringTable::ShrinkNewStrings(int position) {
+ new_space_strings_.Rewind(position);
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+#endif
+}
+
+
+void Heap::ClearInstanceofCache() {
+ set_instanceof_cache_function(the_hole_value());
+}
+
+
+Object* Heap::ToBoolean(bool condition) {
+ return condition ? true_value() : false_value();
+}
+
+
+void Heap::CompletelyClearInstanceofCache() {
+ set_instanceof_cache_map(the_hole_value());
+ set_instanceof_cache_function(the_hole_value());
+}
+
+
+AlwaysAllocateScope::AlwaysAllocateScope(Isolate* isolate)
+ : heap_(isolate->heap()), daf_(isolate) {
+ // We shouldn't hit any nested scopes, because that requires
+ // non-handle code to call handle code. The code still works but
+ // performance will degrade, so we want to catch this situation
+ // in debug mode.
+ DCHECK(heap_->always_allocate_scope_depth_ == 0);
+ heap_->always_allocate_scope_depth_++;
+}
+
+
+AlwaysAllocateScope::~AlwaysAllocateScope() {
+ heap_->always_allocate_scope_depth_--;
+ DCHECK(heap_->always_allocate_scope_depth_ == 0);
+}
+
+
+#ifdef VERIFY_HEAP
+NoWeakObjectVerificationScope::NoWeakObjectVerificationScope() {
+ Isolate* isolate = Isolate::Current();
+ isolate->heap()->no_weak_object_verification_scope_depth_++;
+}
+
+
+NoWeakObjectVerificationScope::~NoWeakObjectVerificationScope() {
+ Isolate* isolate = Isolate::Current();
+ isolate->heap()->no_weak_object_verification_scope_depth_--;
+}
+#endif
+
+
+GCCallbacksScope::GCCallbacksScope(Heap* heap) : heap_(heap) {
+ heap_->gc_callbacks_depth_++;
+}
+
+
+GCCallbacksScope::~GCCallbacksScope() { heap_->gc_callbacks_depth_--; }
+
+
+bool GCCallbacksScope::CheckReenter() {
+ return heap_->gc_callbacks_depth_ == 1;
+}
+
+
+void VerifyPointersVisitor::VisitPointers(Object** start, Object** end) {
+ for (Object** current = start; current < end; current++) {
+ if ((*current)->IsHeapObject()) {
+ HeapObject* object = HeapObject::cast(*current);
+ CHECK(object->GetIsolate()->heap()->Contains(object));
+ CHECK(object->map()->IsMap());
+ }
+ }
+}
+
+
+void VerifySmisVisitor::VisitPointers(Object** start, Object** end) {
+ for (Object** current = start; current < end; current++) {
+ CHECK((*current)->IsSmi());
+ }
+}
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_HEAP_INL_H_
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
new file mode 100644
index 0000000..dfe60fe
--- /dev/null
+++ b/src/heap/heap.cc
@@ -0,0 +1,6159 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#include "src/accessors.h"
+#include "src/api.h"
+#include "src/base/bits.h"
+#include "src/base/once.h"
+#include "src/base/utils/random-number-generator.h"
+#include "src/bootstrapper.h"
+#include "src/codegen.h"
+#include "src/compilation-cache.h"
+#include "src/conversions.h"
+#include "src/cpu-profiler.h"
+#include "src/debug.h"
+#include "src/deoptimizer.h"
+#include "src/global-handles.h"
+#include "src/heap/gc-idle-time-handler.h"
+#include "src/heap/incremental-marking.h"
+#include "src/heap/mark-compact.h"
+#include "src/heap/objects-visiting-inl.h"
+#include "src/heap/objects-visiting.h"
+#include "src/heap/store-buffer.h"
+#include "src/heap-profiler.h"
+#include "src/isolate-inl.h"
+#include "src/natives.h"
+#include "src/runtime-profiler.h"
+#include "src/scopeinfo.h"
+#include "src/snapshot.h"
+#include "src/utils.h"
+#include "src/v8threads.h"
+#include "src/vm-state-inl.h"
+
+#if V8_TARGET_ARCH_ARM && !V8_INTERPRETED_REGEXP
+#include "src/regexp-macro-assembler.h" // NOLINT
+#include "src/arm/regexp-macro-assembler-arm.h" // NOLINT
+#endif
+#if V8_TARGET_ARCH_MIPS && !V8_INTERPRETED_REGEXP
+#include "src/regexp-macro-assembler.h" // NOLINT
+#include "src/mips/regexp-macro-assembler-mips.h" // NOLINT
+#endif
+#if V8_TARGET_ARCH_MIPS64 && !V8_INTERPRETED_REGEXP
+#include "src/regexp-macro-assembler.h"
+#include "src/mips64/regexp-macro-assembler-mips64.h"
+#endif
+
+namespace v8 {
+namespace internal {
+
+
+Heap::Heap()
+ : amount_of_external_allocated_memory_(0),
+ amount_of_external_allocated_memory_at_last_global_gc_(0),
+ isolate_(NULL),
+ code_range_size_(0),
+ // semispace_size_ should be a power of 2 and old_generation_size_ should
+ // be a multiple of Page::kPageSize.
+ reserved_semispace_size_(8 * (kPointerSize / 4) * MB),
+ max_semi_space_size_(8 * (kPointerSize / 4) * MB),
+ initial_semispace_size_(Page::kPageSize),
+ max_old_generation_size_(700ul * (kPointerSize / 4) * MB),
+ max_executable_size_(256ul * (kPointerSize / 4) * MB),
+ // Variables set based on semispace_size_ and old_generation_size_ in
+ // ConfigureHeap.
+ // Will be 4 * reserved_semispace_size_ to ensure that young
+ // generation can be aligned to its size.
+ maximum_committed_(0),
+ survived_since_last_expansion_(0),
+ sweep_generation_(0),
+ always_allocate_scope_depth_(0),
+ contexts_disposed_(0),
+ global_ic_age_(0),
+ flush_monomorphic_ics_(false),
+ scan_on_scavenge_pages_(0),
+ new_space_(this),
+ old_pointer_space_(NULL),
+ old_data_space_(NULL),
+ code_space_(NULL),
+ map_space_(NULL),
+ cell_space_(NULL),
+ property_cell_space_(NULL),
+ lo_space_(NULL),
+ gc_state_(NOT_IN_GC),
+ gc_post_processing_depth_(0),
+ allocations_count_(0),
+ raw_allocations_hash_(0),
+ dump_allocations_hash_countdown_(FLAG_dump_allocations_digest_at_alloc),
+ ms_count_(0),
+ gc_count_(0),
+ remembered_unmapped_pages_index_(0),
+ unflattened_strings_length_(0),
+#ifdef DEBUG
+ allocation_timeout_(0),
+#endif // DEBUG
+ old_generation_allocation_limit_(kMinimumOldGenerationAllocationLimit),
+ old_gen_exhausted_(false),
+ inline_allocation_disabled_(false),
+ store_buffer_rebuilder_(store_buffer()),
+ hidden_string_(NULL),
+ gc_safe_size_of_old_object_(NULL),
+ total_regexp_code_generated_(0),
+ tracer_(this),
+ high_survival_rate_period_length_(0),
+ promoted_objects_size_(0),
+ promotion_rate_(0),
+ semi_space_copied_object_size_(0),
+ semi_space_copied_rate_(0),
+ nodes_died_in_new_space_(0),
+ nodes_copied_in_new_space_(0),
+ nodes_promoted_(0),
+ maximum_size_scavenges_(0),
+ max_gc_pause_(0.0),
+ total_gc_time_ms_(0.0),
+ max_alive_after_gc_(0),
+ min_in_mutator_(kMaxInt),
+ marking_time_(0.0),
+ sweeping_time_(0.0),
+ mark_compact_collector_(this),
+ store_buffer_(this),
+ marking_(this),
+ incremental_marking_(this),
+ gc_count_at_last_idle_gc_(0),
+ full_codegen_bytes_generated_(0),
+ crankshaft_codegen_bytes_generated_(0),
+ gcs_since_last_deopt_(0),
+#ifdef VERIFY_HEAP
+ no_weak_object_verification_scope_depth_(0),
+#endif
+ allocation_sites_scratchpad_length_(0),
+ promotion_queue_(this),
+ configured_(false),
+ external_string_table_(this),
+ chunks_queued_for_free_(NULL),
+ gc_callbacks_depth_(0) {
+// Allow build-time customization of the max semispace size. Building
+// V8 with snapshots and a non-default max semispace size is much
+// easier if you can define it as part of the build environment.
+#if defined(V8_MAX_SEMISPACE_SIZE)
+ max_semi_space_size_ = reserved_semispace_size_ = V8_MAX_SEMISPACE_SIZE;
+#endif
+
+ // Ensure old_generation_size_ is a multiple of kPageSize.
+ DCHECK(MB >= Page::kPageSize);
+
+ memset(roots_, 0, sizeof(roots_[0]) * kRootListLength);
+ set_native_contexts_list(NULL);
+ set_array_buffers_list(Smi::FromInt(0));
+ set_allocation_sites_list(Smi::FromInt(0));
+ set_encountered_weak_collections(Smi::FromInt(0));
+ // Put a dummy entry in the remembered pages so we can find the list the
+ // minidump even if there are no real unmapped pages.
+ RememberUnmappedPage(NULL, false);
+
+ ClearObjectStats(true);
+}
+
+
+intptr_t Heap::Capacity() {
+ if (!HasBeenSetUp()) return 0;
+
+ return new_space_.Capacity() + old_pointer_space_->Capacity() +
+ old_data_space_->Capacity() + code_space_->Capacity() +
+ map_space_->Capacity() + cell_space_->Capacity() +
+ property_cell_space_->Capacity();
+}
+
+
+intptr_t Heap::CommittedMemory() {
+ if (!HasBeenSetUp()) return 0;
+
+ return new_space_.CommittedMemory() + old_pointer_space_->CommittedMemory() +
+ old_data_space_->CommittedMemory() + code_space_->CommittedMemory() +
+ map_space_->CommittedMemory() + cell_space_->CommittedMemory() +
+ property_cell_space_->CommittedMemory() + lo_space_->Size();
+}
+
+
+size_t Heap::CommittedPhysicalMemory() {
+ if (!HasBeenSetUp()) return 0;
+
+ return new_space_.CommittedPhysicalMemory() +
+ old_pointer_space_->CommittedPhysicalMemory() +
+ old_data_space_->CommittedPhysicalMemory() +
+ code_space_->CommittedPhysicalMemory() +
+ map_space_->CommittedPhysicalMemory() +
+ cell_space_->CommittedPhysicalMemory() +
+ property_cell_space_->CommittedPhysicalMemory() +
+ lo_space_->CommittedPhysicalMemory();
+}
+
+
+intptr_t Heap::CommittedMemoryExecutable() {
+ if (!HasBeenSetUp()) return 0;
+
+ return isolate()->memory_allocator()->SizeExecutable();
+}
+
+
+void Heap::UpdateMaximumCommitted() {
+ if (!HasBeenSetUp()) return;
+
+ intptr_t current_committed_memory = CommittedMemory();
+ if (current_committed_memory > maximum_committed_) {
+ maximum_committed_ = current_committed_memory;
+ }
+}
+
+
+intptr_t Heap::Available() {
+ if (!HasBeenSetUp()) return 0;
+
+ return new_space_.Available() + old_pointer_space_->Available() +
+ old_data_space_->Available() + code_space_->Available() +
+ map_space_->Available() + cell_space_->Available() +
+ property_cell_space_->Available();
+}
+
+
+bool Heap::HasBeenSetUp() {
+ return old_pointer_space_ != NULL && old_data_space_ != NULL &&
+ code_space_ != NULL && map_space_ != NULL && cell_space_ != NULL &&
+ property_cell_space_ != NULL && lo_space_ != NULL;
+}
+
+
+int Heap::GcSafeSizeOfOldObject(HeapObject* object) {
+ if (IntrusiveMarking::IsMarked(object)) {
+ return IntrusiveMarking::SizeOfMarkedObject(object);
+ }
+ return object->SizeFromMap(object->map());
+}
+
+
+GarbageCollector Heap::SelectGarbageCollector(AllocationSpace space,
+ const char** reason) {
+ // Is global GC requested?
+ if (space != NEW_SPACE) {
+ isolate_->counters()->gc_compactor_caused_by_request()->Increment();
+ *reason = "GC in old space requested";
+ return MARK_COMPACTOR;
+ }
+
+ if (FLAG_gc_global || (FLAG_stress_compaction && (gc_count_ & 1) != 0)) {
+ *reason = "GC in old space forced by flags";
+ return MARK_COMPACTOR;
+ }
+
+ // Is enough data promoted to justify a global GC?
+ if (OldGenerationAllocationLimitReached()) {
+ isolate_->counters()->gc_compactor_caused_by_promoted_data()->Increment();
+ *reason = "promotion limit reached";
+ return MARK_COMPACTOR;
+ }
+
+ // Have allocation in OLD and LO failed?
+ if (old_gen_exhausted_) {
+ isolate_->counters()
+ ->gc_compactor_caused_by_oldspace_exhaustion()
+ ->Increment();
+ *reason = "old generations exhausted";
+ return MARK_COMPACTOR;
+ }
+
+ // Is there enough space left in OLD to guarantee that a scavenge can
+ // succeed?
+ //
+ // Note that MemoryAllocator->MaxAvailable() undercounts the memory available
+ // for object promotion. It counts only the bytes that the memory
+ // allocator has not yet allocated from the OS and assigned to any space,
+ // and does not count available bytes already in the old space or code
+ // space. Undercounting is safe---we may get an unrequested full GC when
+ // a scavenge would have succeeded.
+ if (isolate_->memory_allocator()->MaxAvailable() <= new_space_.Size()) {
+ isolate_->counters()
+ ->gc_compactor_caused_by_oldspace_exhaustion()
+ ->Increment();
+ *reason = "scavenge might not succeed";
+ return MARK_COMPACTOR;
+ }
+
+ // Default
+ *reason = NULL;
+ return SCAVENGER;
+}
+
+
+// TODO(1238405): Combine the infrastructure for --heap-stats and
+// --log-gc to avoid the complicated preprocessor and flag testing.
+void Heap::ReportStatisticsBeforeGC() {
+// Heap::ReportHeapStatistics will also log NewSpace statistics when
+// compiled --log-gc is set. The following logic is used to avoid
+// double logging.
+#ifdef DEBUG
+ if (FLAG_heap_stats || FLAG_log_gc) new_space_.CollectStatistics();
+ if (FLAG_heap_stats) {
+ ReportHeapStatistics("Before GC");
+ } else if (FLAG_log_gc) {
+ new_space_.ReportStatistics();
+ }
+ if (FLAG_heap_stats || FLAG_log_gc) new_space_.ClearHistograms();
+#else
+ if (FLAG_log_gc) {
+ new_space_.CollectStatistics();
+ new_space_.ReportStatistics();
+ new_space_.ClearHistograms();
+ }
+#endif // DEBUG
+}
+
+
+void Heap::PrintShortHeapStatistics() {
+ if (!FLAG_trace_gc_verbose) return;
+ PrintPID("Memory allocator, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX "d KB\n",
+ isolate_->memory_allocator()->Size() / KB,
+ isolate_->memory_allocator()->Available() / KB);
+ PrintPID("New space, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ new_space_.Size() / KB, new_space_.Available() / KB,
+ new_space_.CommittedMemory() / KB);
+ PrintPID("Old pointers, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ old_pointer_space_->SizeOfObjects() / KB,
+ old_pointer_space_->Available() / KB,
+ old_pointer_space_->CommittedMemory() / KB);
+ PrintPID("Old data space, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ old_data_space_->SizeOfObjects() / KB,
+ old_data_space_->Available() / KB,
+ old_data_space_->CommittedMemory() / KB);
+ PrintPID("Code space, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ code_space_->SizeOfObjects() / KB, code_space_->Available() / KB,
+ code_space_->CommittedMemory() / KB);
+ PrintPID("Map space, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ map_space_->SizeOfObjects() / KB, map_space_->Available() / KB,
+ map_space_->CommittedMemory() / KB);
+ PrintPID("Cell space, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ cell_space_->SizeOfObjects() / KB, cell_space_->Available() / KB,
+ cell_space_->CommittedMemory() / KB);
+ PrintPID("PropertyCell space, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ property_cell_space_->SizeOfObjects() / KB,
+ property_cell_space_->Available() / KB,
+ property_cell_space_->CommittedMemory() / KB);
+ PrintPID("Large object space, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ lo_space_->SizeOfObjects() / KB, lo_space_->Available() / KB,
+ lo_space_->CommittedMemory() / KB);
+ PrintPID("All spaces, used: %6" V8_PTR_PREFIX
+ "d KB"
+ ", available: %6" V8_PTR_PREFIX
+ "d KB"
+ ", committed: %6" V8_PTR_PREFIX "d KB\n",
+ this->SizeOfObjects() / KB, this->Available() / KB,
+ this->CommittedMemory() / KB);
+ PrintPID("External memory reported: %6" V8_PTR_PREFIX "d KB\n",
+ static_cast<intptr_t>(amount_of_external_allocated_memory_ / KB));
+ PrintPID("Total time spent in GC : %.1f ms\n", total_gc_time_ms_);
+}
+
+
+// TODO(1238405): Combine the infrastructure for --heap-stats and
+// --log-gc to avoid the complicated preprocessor and flag testing.
+void Heap::ReportStatisticsAfterGC() {
+// Similar to the before GC, we use some complicated logic to ensure that
+// NewSpace statistics are logged exactly once when --log-gc is turned on.
+#if defined(DEBUG)
+ if (FLAG_heap_stats) {
+ new_space_.CollectStatistics();
+ ReportHeapStatistics("After GC");
+ } else if (FLAG_log_gc) {
+ new_space_.ReportStatistics();
+ }
+#else
+ if (FLAG_log_gc) new_space_.ReportStatistics();
+#endif // DEBUG
+}
+
+
+void Heap::GarbageCollectionPrologue() {
+ {
+ AllowHeapAllocation for_the_first_part_of_prologue;
+ ClearJSFunctionResultCaches();
+ gc_count_++;
+ unflattened_strings_length_ = 0;
+
+ if (FLAG_flush_code && FLAG_flush_code_incrementally) {
+ mark_compact_collector()->EnableCodeFlushing(true);
+ }
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+#endif
+ }
+
+ // Reset GC statistics.
+ promoted_objects_size_ = 0;
+ semi_space_copied_object_size_ = 0;
+ nodes_died_in_new_space_ = 0;
+ nodes_copied_in_new_space_ = 0;
+ nodes_promoted_ = 0;
+
+ UpdateMaximumCommitted();
+
+#ifdef DEBUG
+ DCHECK(!AllowHeapAllocation::IsAllowed() && gc_state_ == NOT_IN_GC);
+
+ if (FLAG_gc_verbose) Print();
+
+ ReportStatisticsBeforeGC();
+#endif // DEBUG
+
+ store_buffer()->GCPrologue();
+
+ if (isolate()->concurrent_osr_enabled()) {
+ isolate()->optimizing_compiler_thread()->AgeBufferedOsrJobs();
+ }
+
+ if (new_space_.IsAtMaximumCapacity()) {
+ maximum_size_scavenges_++;
+ } else {
+ maximum_size_scavenges_ = 0;
+ }
+ CheckNewSpaceExpansionCriteria();
+}
+
+
+intptr_t Heap::SizeOfObjects() {
+ intptr_t total = 0;
+ AllSpaces spaces(this);
+ for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
+ total += space->SizeOfObjects();
+ }
+ return total;
+}
+
+
+void Heap::ClearAllICsByKind(Code::Kind kind) {
+ HeapObjectIterator it(code_space());
+
+ for (Object* object = it.Next(); object != NULL; object = it.Next()) {
+ Code* code = Code::cast(object);
+ Code::Kind current_kind = code->kind();
+ if (current_kind == Code::FUNCTION ||
+ current_kind == Code::OPTIMIZED_FUNCTION) {
+ code->ClearInlineCaches(kind);
+ }
+ }
+}
+
+
+void Heap::RepairFreeListsAfterBoot() {
+ PagedSpaces spaces(this);
+ for (PagedSpace* space = spaces.next(); space != NULL;
+ space = spaces.next()) {
+ space->RepairFreeListsAfterBoot();
+ }
+}
+
+
+void Heap::ProcessPretenuringFeedback() {
+ if (FLAG_allocation_site_pretenuring) {
+ int tenure_decisions = 0;
+ int dont_tenure_decisions = 0;
+ int allocation_mementos_found = 0;
+ int allocation_sites = 0;
+ int active_allocation_sites = 0;
+
+ // If the scratchpad overflowed, we have to iterate over the allocation
+ // sites list.
+ // TODO(hpayer): We iterate over the whole list of allocation sites when
+ // we grew to the maximum semi-space size to deopt maybe tenured
+ // allocation sites. We could hold the maybe tenured allocation sites
+ // in a seperate data structure if this is a performance problem.
+ bool deopt_maybe_tenured = DeoptMaybeTenuredAllocationSites();
+ bool use_scratchpad =
+ allocation_sites_scratchpad_length_ < kAllocationSiteScratchpadSize &&
+ !deopt_maybe_tenured;
+
+ int i = 0;
+ Object* list_element = allocation_sites_list();
+ bool trigger_deoptimization = false;
+ bool maximum_size_scavenge = MaximumSizeScavenge();
+ while (use_scratchpad ? i < allocation_sites_scratchpad_length_
+ : list_element->IsAllocationSite()) {
+ AllocationSite* site =
+ use_scratchpad
+ ? AllocationSite::cast(allocation_sites_scratchpad()->get(i))
+ : AllocationSite::cast(list_element);
+ allocation_mementos_found += site->memento_found_count();
+ if (site->memento_found_count() > 0) {
+ active_allocation_sites++;
+ if (site->DigestPretenuringFeedback(maximum_size_scavenge)) {
+ trigger_deoptimization = true;
+ }
+ if (site->GetPretenureMode() == TENURED) {
+ tenure_decisions++;
+ } else {
+ dont_tenure_decisions++;
+ }
+ allocation_sites++;
+ }
+
+ if (deopt_maybe_tenured && site->IsMaybeTenure()) {
+ site->set_deopt_dependent_code(true);
+ trigger_deoptimization = true;
+ }
+
+ if (use_scratchpad) {
+ i++;
+ } else {
+ list_element = site->weak_next();
+ }
+ }
+
+ if (trigger_deoptimization) {
+ isolate_->stack_guard()->RequestDeoptMarkedAllocationSites();
+ }
+
+ FlushAllocationSitesScratchpad();
+
+ if (FLAG_trace_pretenuring_statistics &&
+ (allocation_mementos_found > 0 || tenure_decisions > 0 ||
+ dont_tenure_decisions > 0)) {
+ PrintF(
+ "GC: (mode, #visited allocation sites, #active allocation sites, "
+ "#mementos, #tenure decisions, #donttenure decisions) "
+ "(%s, %d, %d, %d, %d, %d)\n",
+ use_scratchpad ? "use scratchpad" : "use list", allocation_sites,
+ active_allocation_sites, allocation_mementos_found, tenure_decisions,
+ dont_tenure_decisions);
+ }
+ }
+}
+
+
+void Heap::DeoptMarkedAllocationSites() {
+ // TODO(hpayer): If iterating over the allocation sites list becomes a
+ // performance issue, use a cache heap data structure instead (similar to the
+ // allocation sites scratchpad).
+ Object* list_element = allocation_sites_list();
+ while (list_element->IsAllocationSite()) {
+ AllocationSite* site = AllocationSite::cast(list_element);
+ if (site->deopt_dependent_code()) {
+ site->dependent_code()->MarkCodeForDeoptimization(
+ isolate_, DependentCode::kAllocationSiteTenuringChangedGroup);
+ site->set_deopt_dependent_code(false);
+ }
+ list_element = site->weak_next();
+ }
+ Deoptimizer::DeoptimizeMarkedCode(isolate_);
+}
+
+
+void Heap::GarbageCollectionEpilogue() {
+ store_buffer()->GCEpilogue();
+
+ // In release mode, we only zap the from space under heap verification.
+ if (Heap::ShouldZapGarbage()) {
+ ZapFromSpace();
+ }
+
+ // Process pretenuring feedback and update allocation sites.
+ ProcessPretenuringFeedback();
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+#endif
+
+ AllowHeapAllocation for_the_rest_of_the_epilogue;
+
+#ifdef DEBUG
+ if (FLAG_print_global_handles) isolate_->global_handles()->Print();
+ if (FLAG_print_handles) PrintHandles();
+ if (FLAG_gc_verbose) Print();
+ if (FLAG_code_stats) ReportCodeStatistics("After GC");
+#endif
+ if (FLAG_deopt_every_n_garbage_collections > 0) {
+ // TODO(jkummerow/ulan/jarin): This is not safe! We can't assume that
+ // the topmost optimized frame can be deoptimized safely, because it
+ // might not have a lazy bailout point right after its current PC.
+ if (++gcs_since_last_deopt_ == FLAG_deopt_every_n_garbage_collections) {
+ Deoptimizer::DeoptimizeAll(isolate());
+ gcs_since_last_deopt_ = 0;
+ }
+ }
+
+ UpdateMaximumCommitted();
+
+ isolate_->counters()->alive_after_last_gc()->Set(
+ static_cast<int>(SizeOfObjects()));
+
+ isolate_->counters()->string_table_capacity()->Set(
+ string_table()->Capacity());
+ isolate_->counters()->number_of_symbols()->Set(
+ string_table()->NumberOfElements());
+
+ if (full_codegen_bytes_generated_ + crankshaft_codegen_bytes_generated_ > 0) {
+ isolate_->counters()->codegen_fraction_crankshaft()->AddSample(
+ static_cast<int>((crankshaft_codegen_bytes_generated_ * 100.0) /
+ (crankshaft_codegen_bytes_generated_ +
+ full_codegen_bytes_generated_)));
+ }
+
+ if (CommittedMemory() > 0) {
+ isolate_->counters()->external_fragmentation_total()->AddSample(
+ static_cast<int>(100 - (SizeOfObjects() * 100.0) / CommittedMemory()));
+
+ isolate_->counters()->heap_fraction_new_space()->AddSample(static_cast<int>(
+ (new_space()->CommittedMemory() * 100.0) / CommittedMemory()));
+ isolate_->counters()->heap_fraction_old_pointer_space()->AddSample(
+ static_cast<int>((old_pointer_space()->CommittedMemory() * 100.0) /
+ CommittedMemory()));
+ isolate_->counters()->heap_fraction_old_data_space()->AddSample(
+ static_cast<int>((old_data_space()->CommittedMemory() * 100.0) /
+ CommittedMemory()));
+ isolate_->counters()->heap_fraction_code_space()->AddSample(
+ static_cast<int>((code_space()->CommittedMemory() * 100.0) /
+ CommittedMemory()));
+ isolate_->counters()->heap_fraction_map_space()->AddSample(static_cast<int>(
+ (map_space()->CommittedMemory() * 100.0) / CommittedMemory()));
+ isolate_->counters()->heap_fraction_cell_space()->AddSample(
+ static_cast<int>((cell_space()->CommittedMemory() * 100.0) /
+ CommittedMemory()));
+ isolate_->counters()->heap_fraction_property_cell_space()->AddSample(
+ static_cast<int>((property_cell_space()->CommittedMemory() * 100.0) /
+ CommittedMemory()));
+ isolate_->counters()->heap_fraction_lo_space()->AddSample(static_cast<int>(
+ (lo_space()->CommittedMemory() * 100.0) / CommittedMemory()));
+
+ isolate_->counters()->heap_sample_total_committed()->AddSample(
+ static_cast<int>(CommittedMemory() / KB));
+ isolate_->counters()->heap_sample_total_used()->AddSample(
+ static_cast<int>(SizeOfObjects() / KB));
+ isolate_->counters()->heap_sample_map_space_committed()->AddSample(
+ static_cast<int>(map_space()->CommittedMemory() / KB));
+ isolate_->counters()->heap_sample_cell_space_committed()->AddSample(
+ static_cast<int>(cell_space()->CommittedMemory() / KB));
+ isolate_->counters()
+ ->heap_sample_property_cell_space_committed()
+ ->AddSample(
+ static_cast<int>(property_cell_space()->CommittedMemory() / KB));
+ isolate_->counters()->heap_sample_code_space_committed()->AddSample(
+ static_cast<int>(code_space()->CommittedMemory() / KB));
+
+ isolate_->counters()->heap_sample_maximum_committed()->AddSample(
+ static_cast<int>(MaximumCommittedMemory() / KB));
+ }
+
+#define UPDATE_COUNTERS_FOR_SPACE(space) \
+ isolate_->counters()->space##_bytes_available()->Set( \
+ static_cast<int>(space()->Available())); \
+ isolate_->counters()->space##_bytes_committed()->Set( \
+ static_cast<int>(space()->CommittedMemory())); \
+ isolate_->counters()->space##_bytes_used()->Set( \
+ static_cast<int>(space()->SizeOfObjects()));
+#define UPDATE_FRAGMENTATION_FOR_SPACE(space) \
+ if (space()->CommittedMemory() > 0) { \
+ isolate_->counters()->external_fragmentation_##space()->AddSample( \
+ static_cast<int>(100 - \
+ (space()->SizeOfObjects() * 100.0) / \
+ space()->CommittedMemory())); \
+ }
+#define UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(space) \
+ UPDATE_COUNTERS_FOR_SPACE(space) \
+ UPDATE_FRAGMENTATION_FOR_SPACE(space)
+
+ UPDATE_COUNTERS_FOR_SPACE(new_space)
+ UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(old_pointer_space)
+ UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(old_data_space)
+ UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(code_space)
+ UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(map_space)
+ UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(cell_space)
+ UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(property_cell_space)
+ UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(lo_space)
+#undef UPDATE_COUNTERS_FOR_SPACE
+#undef UPDATE_FRAGMENTATION_FOR_SPACE
+#undef UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE
+
+#ifdef DEBUG
+ ReportStatisticsAfterGC();
+#endif // DEBUG
+
+ // Remember the last top pointer so that we can later find out
+ // whether we allocated in new space since the last GC.
+ new_space_top_after_last_gc_ = new_space()->top();
+}
+
+
+void Heap::CollectAllGarbage(int flags, const char* gc_reason,
+ const v8::GCCallbackFlags gc_callback_flags) {
+ // Since we are ignoring the return value, the exact choice of space does
+ // not matter, so long as we do not specify NEW_SPACE, which would not
+ // cause a full GC.
+ mark_compact_collector_.SetFlags(flags);
+ CollectGarbage(OLD_POINTER_SPACE, gc_reason, gc_callback_flags);
+ mark_compact_collector_.SetFlags(kNoGCFlags);
+}
+
+
+void Heap::CollectAllAvailableGarbage(const char* gc_reason) {
+ // Since we are ignoring the return value, the exact choice of space does
+ // not matter, so long as we do not specify NEW_SPACE, which would not
+ // cause a full GC.
+ // Major GC would invoke weak handle callbacks on weakly reachable
+ // handles, but won't collect weakly reachable objects until next
+ // major GC. Therefore if we collect aggressively and weak handle callback
+ // has been invoked, we rerun major GC to release objects which become
+ // garbage.
+ // Note: as weak callbacks can execute arbitrary code, we cannot
+ // hope that eventually there will be no weak callbacks invocations.
+ // Therefore stop recollecting after several attempts.
+ if (isolate()->concurrent_recompilation_enabled()) {
+ // The optimizing compiler may be unnecessarily holding on to memory.
+ DisallowHeapAllocation no_recursive_gc;
+ isolate()->optimizing_compiler_thread()->Flush();
+ }
+ mark_compact_collector()->SetFlags(kMakeHeapIterableMask |
+ kReduceMemoryFootprintMask);
+ isolate_->compilation_cache()->Clear();
+ const int kMaxNumberOfAttempts = 7;
+ const int kMinNumberOfAttempts = 2;
+ for (int attempt = 0; attempt < kMaxNumberOfAttempts; attempt++) {
+ if (!CollectGarbage(MARK_COMPACTOR, gc_reason, NULL) &&
+ attempt + 1 >= kMinNumberOfAttempts) {
+ break;
+ }
+ }
+ mark_compact_collector()->SetFlags(kNoGCFlags);
+ new_space_.Shrink();
+ UncommitFromSpace();
+ incremental_marking()->UncommitMarkingDeque();
+}
+
+
+void Heap::EnsureFillerObjectAtTop() {
+ // There may be an allocation memento behind every object in new space.
+ // If we evacuate a not full new space or if we are on the last page of
+ // the new space, then there may be uninitialized memory behind the top
+ // pointer of the new space page. We store a filler object there to
+ // identify the unused space.
+ Address from_top = new_space_.top();
+ Address from_limit = new_space_.limit();
+ if (from_top < from_limit) {
+ int remaining_in_page = static_cast<int>(from_limit - from_top);
+ CreateFillerObjectAt(from_top, remaining_in_page);
+ }
+}
+
+
+bool Heap::CollectGarbage(GarbageCollector collector, const char* gc_reason,
+ const char* collector_reason,
+ const v8::GCCallbackFlags gc_callback_flags) {
+ // The VM is in the GC state until exiting this function.
+ VMState<GC> state(isolate_);
+
+#ifdef DEBUG
+ // Reset the allocation timeout to the GC interval, but make sure to
+ // allow at least a few allocations after a collection. The reason
+ // for this is that we have a lot of allocation sequences and we
+ // assume that a garbage collection will allow the subsequent
+ // allocation attempts to go through.
+ allocation_timeout_ = Max(6, FLAG_gc_interval);
+#endif
+
+ EnsureFillerObjectAtTop();
+
+ if (collector == SCAVENGER && !incremental_marking()->IsStopped()) {
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Scavenge during marking.\n");
+ }
+ }
+
+ if (collector == MARK_COMPACTOR &&
+ !mark_compact_collector()->abort_incremental_marking() &&
+ !incremental_marking()->IsStopped() &&
+ !incremental_marking()->should_hurry() &&
+ FLAG_incremental_marking_steps) {
+ // Make progress in incremental marking.
+ const intptr_t kStepSizeWhenDelayedByScavenge = 1 * MB;
+ incremental_marking()->Step(kStepSizeWhenDelayedByScavenge,
+ IncrementalMarking::NO_GC_VIA_STACK_GUARD);
+ if (!incremental_marking()->IsComplete() && !FLAG_gc_global) {
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Delaying MarkSweep.\n");
+ }
+ collector = SCAVENGER;
+ collector_reason = "incremental marking delaying mark-sweep";
+ }
+ }
+
+ bool next_gc_likely_to_collect_more = false;
+
+ {
+ tracer()->Start(collector, gc_reason, collector_reason);
+ DCHECK(AllowHeapAllocation::IsAllowed());
+ DisallowHeapAllocation no_allocation_during_gc;
+ GarbageCollectionPrologue();
+
+ {
+ HistogramTimerScope histogram_timer_scope(
+ (collector == SCAVENGER) ? isolate_->counters()->gc_scavenger()
+ : isolate_->counters()->gc_compactor());
+ next_gc_likely_to_collect_more =
+ PerformGarbageCollection(collector, gc_callback_flags);
+ }
+
+ GarbageCollectionEpilogue();
+ tracer()->Stop();
+ }
+
+ // Start incremental marking for the next cycle. The heap snapshot
+ // generator needs incremental marking to stay off after it aborted.
+ if (!mark_compact_collector()->abort_incremental_marking() &&
+ WorthActivatingIncrementalMarking()) {
+ incremental_marking()->Start();
+ }
+
+ return next_gc_likely_to_collect_more;
+}
+
+
+int Heap::NotifyContextDisposed() {
+ if (isolate()->concurrent_recompilation_enabled()) {
+ // Flush the queued recompilation tasks.
+ isolate()->optimizing_compiler_thread()->Flush();
+ }
+ flush_monomorphic_ics_ = true;
+ AgeInlineCaches();
+ return ++contexts_disposed_;
+}
+
+
+void Heap::MoveElements(FixedArray* array, int dst_index, int src_index,
+ int len) {
+ if (len == 0) return;
+
+ DCHECK(array->map() != fixed_cow_array_map());
+ Object** dst_objects = array->data_start() + dst_index;
+ MemMove(dst_objects, array->data_start() + src_index, len * kPointerSize);
+ if (!InNewSpace(array)) {
+ for (int i = 0; i < len; i++) {
+ // TODO(hpayer): check store buffer for entries
+ if (InNewSpace(dst_objects[i])) {
+ RecordWrite(array->address(), array->OffsetOfElementAt(dst_index + i));
+ }
+ }
+ }
+ incremental_marking()->RecordWrites(array);
+}
+
+
+#ifdef VERIFY_HEAP
+// Helper class for verifying the string table.
+class StringTableVerifier : public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object** end) {
+ // Visit all HeapObject pointers in [start, end).
+ for (Object** p = start; p < end; p++) {
+ if ((*p)->IsHeapObject()) {
+ // Check that the string is actually internalized.
+ CHECK((*p)->IsTheHole() || (*p)->IsUndefined() ||
+ (*p)->IsInternalizedString());
+ }
+ }
+ }
+};
+
+
+static void VerifyStringTable(Heap* heap) {
+ StringTableVerifier verifier;
+ heap->string_table()->IterateElements(&verifier);
+}
+#endif // VERIFY_HEAP
+
+
+static bool AbortIncrementalMarkingAndCollectGarbage(
+ Heap* heap, AllocationSpace space, const char* gc_reason = NULL) {
+ heap->mark_compact_collector()->SetFlags(Heap::kAbortIncrementalMarkingMask);
+ bool result = heap->CollectGarbage(space, gc_reason);
+ heap->mark_compact_collector()->SetFlags(Heap::kNoGCFlags);
+ return result;
+}
+
+
+void Heap::ReserveSpace(int* sizes, Address* locations_out) {
+ bool gc_performed = true;
+ int counter = 0;
+ static const int kThreshold = 20;
+ while (gc_performed && counter++ < kThreshold) {
+ gc_performed = false;
+ DCHECK(NEW_SPACE == FIRST_PAGED_SPACE - 1);
+ for (int space = NEW_SPACE; space <= LAST_PAGED_SPACE; space++) {
+ if (sizes[space] != 0) {
+ AllocationResult allocation;
+ if (space == NEW_SPACE) {
+ allocation = new_space()->AllocateRaw(sizes[space]);
+ } else {
+ allocation = paged_space(space)->AllocateRaw(sizes[space]);
+ }
+ FreeListNode* node;
+ if (!allocation.To(&node)) {
+ if (space == NEW_SPACE) {
+ Heap::CollectGarbage(NEW_SPACE,
+ "failed to reserve space in the new space");
+ } else {
+ AbortIncrementalMarkingAndCollectGarbage(
+ this, static_cast<AllocationSpace>(space),
+ "failed to reserve space in paged space");
+ }
+ gc_performed = true;
+ break;
+ } else {
+ // Mark with a free list node, in case we have a GC before
+ // deserializing.
+ node->set_size(this, sizes[space]);
+ locations_out[space] = node->address();
+ }
+ }
+ }
+ }
+
+ if (gc_performed) {
+ // Failed to reserve the space after several attempts.
+ V8::FatalProcessOutOfMemory("Heap::ReserveSpace");
+ }
+}
+
+
+void Heap::EnsureFromSpaceIsCommitted() {
+ if (new_space_.CommitFromSpaceIfNeeded()) return;
+
+ // Committing memory to from space failed.
+ // Memory is exhausted and we will die.
+ V8::FatalProcessOutOfMemory("Committing semi space failed.");
+}
+
+
+void Heap::ClearJSFunctionResultCaches() {
+ if (isolate_->bootstrapper()->IsActive()) return;
+
+ Object* context = native_contexts_list();
+ while (!context->IsUndefined()) {
+ // Get the caches for this context. GC can happen when the context
+ // is not fully initialized, so the caches can be undefined.
+ Object* caches_or_undefined =
+ Context::cast(context)->get(Context::JSFUNCTION_RESULT_CACHES_INDEX);
+ if (!caches_or_undefined->IsUndefined()) {
+ FixedArray* caches = FixedArray::cast(caches_or_undefined);
+ // Clear the caches:
+ int length = caches->length();
+ for (int i = 0; i < length; i++) {
+ JSFunctionResultCache::cast(caches->get(i))->Clear();
+ }
+ }
+ // Get the next context:
+ context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
+ }
+}
+
+
+void Heap::ClearNormalizedMapCaches() {
+ if (isolate_->bootstrapper()->IsActive() &&
+ !incremental_marking()->IsMarking()) {
+ return;
+ }
+
+ Object* context = native_contexts_list();
+ while (!context->IsUndefined()) {
+ // GC can happen when the context is not fully initialized,
+ // so the cache can be undefined.
+ Object* cache =
+ Context::cast(context)->get(Context::NORMALIZED_MAP_CACHE_INDEX);
+ if (!cache->IsUndefined()) {
+ NormalizedMapCache::cast(cache)->Clear();
+ }
+ context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
+ }
+}
+
+
+void Heap::UpdateSurvivalStatistics(int start_new_space_size) {
+ if (start_new_space_size == 0) return;
+
+ promotion_rate_ = (static_cast<double>(promoted_objects_size_) /
+ static_cast<double>(start_new_space_size) * 100);
+
+ semi_space_copied_rate_ =
+ (static_cast<double>(semi_space_copied_object_size_) /
+ static_cast<double>(start_new_space_size) * 100);
+
+ double survival_rate = promotion_rate_ + semi_space_copied_rate_;
+
+ if (survival_rate > kYoungSurvivalRateHighThreshold) {
+ high_survival_rate_period_length_++;
+ } else {
+ high_survival_rate_period_length_ = 0;
+ }
+}
+
+bool Heap::PerformGarbageCollection(
+ GarbageCollector collector, const v8::GCCallbackFlags gc_callback_flags) {
+ int freed_global_handles = 0;
+
+ if (collector != SCAVENGER) {
+ PROFILE(isolate_, CodeMovingGCEvent());
+ }
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ VerifyStringTable(this);
+ }
+#endif
+
+ GCType gc_type =
+ collector == MARK_COMPACTOR ? kGCTypeMarkSweepCompact : kGCTypeScavenge;
+
+ {
+ GCCallbacksScope scope(this);
+ if (scope.CheckReenter()) {
+ AllowHeapAllocation allow_allocation;
+ GCTracer::Scope scope(tracer(), GCTracer::Scope::EXTERNAL);
+ VMState<EXTERNAL> state(isolate_);
+ HandleScope handle_scope(isolate_);
+ CallGCPrologueCallbacks(gc_type, kNoGCCallbackFlags);
+ }
+ }
+
+ EnsureFromSpaceIsCommitted();
+
+ int start_new_space_size = Heap::new_space()->SizeAsInt();
+
+ if (IsHighSurvivalRate()) {
+ // We speed up the incremental marker if it is running so that it
+ // does not fall behind the rate of promotion, which would cause a
+ // constantly growing old space.
+ incremental_marking()->NotifyOfHighPromotionRate();
+ }
+
+ if (collector == MARK_COMPACTOR) {
+ // Perform mark-sweep with optional compaction.
+ MarkCompact();
+ sweep_generation_++;
+ // Temporarily set the limit for case when PostGarbageCollectionProcessing
+ // allocates and triggers GC. The real limit is set at after
+ // PostGarbageCollectionProcessing.
+ old_generation_allocation_limit_ =
+ OldGenerationAllocationLimit(PromotedSpaceSizeOfObjects(), 0);
+ old_gen_exhausted_ = false;
+ } else {
+ Scavenge();
+ }
+
+ UpdateSurvivalStatistics(start_new_space_size);
+
+ isolate_->counters()->objs_since_last_young()->Set(0);
+
+ // Callbacks that fire after this point might trigger nested GCs and
+ // restart incremental marking, the assertion can't be moved down.
+ DCHECK(collector == SCAVENGER || incremental_marking()->IsStopped());
+
+ gc_post_processing_depth_++;
+ {
+ AllowHeapAllocation allow_allocation;
+ GCTracer::Scope scope(tracer(), GCTracer::Scope::EXTERNAL);
+ freed_global_handles =
+ isolate_->global_handles()->PostGarbageCollectionProcessing(collector);
+ }
+ gc_post_processing_depth_--;
+
+ isolate_->eternal_handles()->PostGarbageCollectionProcessing(this);
+
+ // Update relocatables.
+ Relocatable::PostGarbageCollectionProcessing(isolate_);
+
+ if (collector == MARK_COMPACTOR) {
+ // Register the amount of external allocated memory.
+ amount_of_external_allocated_memory_at_last_global_gc_ =
+ amount_of_external_allocated_memory_;
+ old_generation_allocation_limit_ = OldGenerationAllocationLimit(
+ PromotedSpaceSizeOfObjects(), freed_global_handles);
+ }
+
+ {
+ GCCallbacksScope scope(this);
+ if (scope.CheckReenter()) {
+ AllowHeapAllocation allow_allocation;
+ GCTracer::Scope scope(tracer(), GCTracer::Scope::EXTERNAL);
+ VMState<EXTERNAL> state(isolate_);
+ HandleScope handle_scope(isolate_);
+ CallGCEpilogueCallbacks(gc_type, gc_callback_flags);
+ }
+ }
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ VerifyStringTable(this);
+ }
+#endif
+
+ return freed_global_handles > 0;
+}
+
+
+void Heap::CallGCPrologueCallbacks(GCType gc_type, GCCallbackFlags flags) {
+ for (int i = 0; i < gc_prologue_callbacks_.length(); ++i) {
+ if (gc_type & gc_prologue_callbacks_[i].gc_type) {
+ if (!gc_prologue_callbacks_[i].pass_isolate_) {
+ v8::GCPrologueCallback callback =
+ reinterpret_cast<v8::GCPrologueCallback>(
+ gc_prologue_callbacks_[i].callback);
+ callback(gc_type, flags);
+ } else {
+ v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(this->isolate());
+ gc_prologue_callbacks_[i].callback(isolate, gc_type, flags);
+ }
+ }
+ }
+}
+
+
+void Heap::CallGCEpilogueCallbacks(GCType gc_type,
+ GCCallbackFlags gc_callback_flags) {
+ for (int i = 0; i < gc_epilogue_callbacks_.length(); ++i) {
+ if (gc_type & gc_epilogue_callbacks_[i].gc_type) {
+ if (!gc_epilogue_callbacks_[i].pass_isolate_) {
+ v8::GCPrologueCallback callback =
+ reinterpret_cast<v8::GCPrologueCallback>(
+ gc_epilogue_callbacks_[i].callback);
+ callback(gc_type, gc_callback_flags);
+ } else {
+ v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(this->isolate());
+ gc_epilogue_callbacks_[i].callback(isolate, gc_type, gc_callback_flags);
+ }
+ }
+ }
+}
+
+
+void Heap::MarkCompact() {
+ gc_state_ = MARK_COMPACT;
+ LOG(isolate_, ResourceEvent("markcompact", "begin"));
+
+ uint64_t size_of_objects_before_gc = SizeOfObjects();
+
+ mark_compact_collector_.Prepare();
+
+ ms_count_++;
+
+ MarkCompactPrologue();
+
+ mark_compact_collector_.CollectGarbage();
+
+ LOG(isolate_, ResourceEvent("markcompact", "end"));
+
+ gc_state_ = NOT_IN_GC;
+
+ isolate_->counters()->objs_since_last_full()->Set(0);
+
+ flush_monomorphic_ics_ = false;
+
+ if (FLAG_allocation_site_pretenuring) {
+ EvaluateOldSpaceLocalPretenuring(size_of_objects_before_gc);
+ }
+}
+
+
+void Heap::MarkCompactPrologue() {
+ // At any old GC clear the keyed lookup cache to enable collection of unused
+ // maps.
+ isolate_->keyed_lookup_cache()->Clear();
+ isolate_->context_slot_cache()->Clear();
+ isolate_->descriptor_lookup_cache()->Clear();
+ RegExpResultsCache::Clear(string_split_cache());
+ RegExpResultsCache::Clear(regexp_multiple_cache());
+
+ isolate_->compilation_cache()->MarkCompactPrologue();
+
+ CompletelyClearInstanceofCache();
+
+ FlushNumberStringCache();
+ if (FLAG_cleanup_code_caches_at_gc) {
+ polymorphic_code_cache()->set_cache(undefined_value());
+ }
+
+ ClearNormalizedMapCaches();
+}
+
+
+// Helper class for copying HeapObjects
+class ScavengeVisitor : public ObjectVisitor {
+ public:
+ explicit ScavengeVisitor(Heap* heap) : heap_(heap) {}
+
+ void VisitPointer(Object** p) { ScavengePointer(p); }
+
+ void VisitPointers(Object** start, Object** end) {
+ // Copy all HeapObject pointers in [start, end)
+ for (Object** p = start; p < end; p++) ScavengePointer(p);
+ }
+
+ private:
+ void ScavengePointer(Object** p) {
+ Object* object = *p;
+ if (!heap_->InNewSpace(object)) return;
+ Heap::ScavengeObject(reinterpret_cast<HeapObject**>(p),
+ reinterpret_cast<HeapObject*>(object));
+ }
+
+ Heap* heap_;
+};
+
+
+#ifdef VERIFY_HEAP
+// Visitor class to verify pointers in code or data space do not point into
+// new space.
+class VerifyNonPointerSpacePointersVisitor : public ObjectVisitor {
+ public:
+ explicit VerifyNonPointerSpacePointersVisitor(Heap* heap) : heap_(heap) {}
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** current = start; current < end; current++) {
+ if ((*current)->IsHeapObject()) {
+ CHECK(!heap_->InNewSpace(HeapObject::cast(*current)));
+ }
+ }
+ }
+
+ private:
+ Heap* heap_;
+};
+
+
+static void VerifyNonPointerSpacePointers(Heap* heap) {
+ // Verify that there are no pointers to new space in spaces where we
+ // do not expect them.
+ VerifyNonPointerSpacePointersVisitor v(heap);
+ HeapObjectIterator code_it(heap->code_space());
+ for (HeapObject* object = code_it.Next(); object != NULL;
+ object = code_it.Next())
+ object->Iterate(&v);
+
+ HeapObjectIterator data_it(heap->old_data_space());
+ for (HeapObject* object = data_it.Next(); object != NULL;
+ object = data_it.Next())
+ object->Iterate(&v);
+}
+#endif // VERIFY_HEAP
+
+
+void Heap::CheckNewSpaceExpansionCriteria() {
+ if (new_space_.TotalCapacity() < new_space_.MaximumCapacity() &&
+ survived_since_last_expansion_ > new_space_.TotalCapacity()) {
+ // Grow the size of new space if there is room to grow, enough data
+ // has survived scavenge since the last expansion and we are not in
+ // high promotion mode.
+ new_space_.Grow();
+ survived_since_last_expansion_ = 0;
+ }
+}
+
+
+static bool IsUnscavengedHeapObject(Heap* heap, Object** p) {
+ return heap->InNewSpace(*p) &&
+ !HeapObject::cast(*p)->map_word().IsForwardingAddress();
+}
+
+
+void Heap::ScavengeStoreBufferCallback(Heap* heap, MemoryChunk* page,
+ StoreBufferEvent event) {
+ heap->store_buffer_rebuilder_.Callback(page, event);
+}
+
+
+void StoreBufferRebuilder::Callback(MemoryChunk* page, StoreBufferEvent event) {
+ if (event == kStoreBufferStartScanningPagesEvent) {
+ start_of_current_page_ = NULL;
+ current_page_ = NULL;
+ } else if (event == kStoreBufferScanningPageEvent) {
+ if (current_page_ != NULL) {
+ // If this page already overflowed the store buffer during this iteration.
+ if (current_page_->scan_on_scavenge()) {
+ // Then we should wipe out the entries that have been added for it.
+ store_buffer_->SetTop(start_of_current_page_);
+ } else if (store_buffer_->Top() - start_of_current_page_ >=
+ (store_buffer_->Limit() - store_buffer_->Top()) >> 2) {
+ // Did we find too many pointers in the previous page? The heuristic is
+ // that no page can take more then 1/5 the remaining slots in the store
+ // buffer.
+ current_page_->set_scan_on_scavenge(true);
+ store_buffer_->SetTop(start_of_current_page_);
+ } else {
+ // In this case the page we scanned took a reasonable number of slots in
+ // the store buffer. It has now been rehabilitated and is no longer
+ // marked scan_on_scavenge.
+ DCHECK(!current_page_->scan_on_scavenge());
+ }
+ }
+ start_of_current_page_ = store_buffer_->Top();
+ current_page_ = page;
+ } else if (event == kStoreBufferFullEvent) {
+ // The current page overflowed the store buffer again. Wipe out its entries
+ // in the store buffer and mark it scan-on-scavenge again. This may happen
+ // several times while scanning.
+ if (current_page_ == NULL) {
+ // Store Buffer overflowed while scanning promoted objects. These are not
+ // in any particular page, though they are likely to be clustered by the
+ // allocation routines.
+ store_buffer_->EnsureSpace(StoreBuffer::kStoreBufferSize / 2);
+ } else {
+ // Store Buffer overflowed while scanning a particular old space page for
+ // pointers to new space.
+ DCHECK(current_page_ == page);
+ DCHECK(page != NULL);
+ current_page_->set_scan_on_scavenge(true);
+ DCHECK(start_of_current_page_ != store_buffer_->Top());
+ store_buffer_->SetTop(start_of_current_page_);
+ }
+ } else {
+ UNREACHABLE();
+ }
+}
+
+
+void PromotionQueue::Initialize() {
+ // Assumes that a NewSpacePage exactly fits a number of promotion queue
+ // entries (where each is a pair of intptr_t). This allows us to simplify
+ // the test fpr when to switch pages.
+ DCHECK((Page::kPageSize - MemoryChunk::kBodyOffset) % (2 * kPointerSize) ==
+ 0);
+ limit_ = reinterpret_cast<intptr_t*>(heap_->new_space()->ToSpaceStart());
+ front_ = rear_ =
+ reinterpret_cast<intptr_t*>(heap_->new_space()->ToSpaceEnd());
+ emergency_stack_ = NULL;
+}
+
+
+void PromotionQueue::RelocateQueueHead() {
+ DCHECK(emergency_stack_ == NULL);
+
+ Page* p = Page::FromAllocationTop(reinterpret_cast<Address>(rear_));
+ intptr_t* head_start = rear_;
+ intptr_t* head_end = Min(front_, reinterpret_cast<intptr_t*>(p->area_end()));
+
+ int entries_count =
+ static_cast<int>(head_end - head_start) / kEntrySizeInWords;
+
+ emergency_stack_ = new List<Entry>(2 * entries_count);
+
+ while (head_start != head_end) {
+ int size = static_cast<int>(*(head_start++));
+ HeapObject* obj = reinterpret_cast<HeapObject*>(*(head_start++));
+ emergency_stack_->Add(Entry(obj, size));
+ }
+ rear_ = head_end;
+}
+
+
+class ScavengeWeakObjectRetainer : public WeakObjectRetainer {
+ public:
+ explicit ScavengeWeakObjectRetainer(Heap* heap) : heap_(heap) {}
+
+ virtual Object* RetainAs(Object* object) {
+ if (!heap_->InFromSpace(object)) {
+ return object;
+ }
+
+ MapWord map_word = HeapObject::cast(object)->map_word();
+ if (map_word.IsForwardingAddress()) {
+ return map_word.ToForwardingAddress();
+ }
+ return NULL;
+ }
+
+ private:
+ Heap* heap_;
+};
+
+
+void Heap::Scavenge() {
+ RelocationLock relocation_lock(this);
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) VerifyNonPointerSpacePointers(this);
+#endif
+
+ gc_state_ = SCAVENGE;
+
+ // Implements Cheney's copying algorithm
+ LOG(isolate_, ResourceEvent("scavenge", "begin"));
+
+ // Clear descriptor cache.
+ isolate_->descriptor_lookup_cache()->Clear();
+
+ // Used for updating survived_since_last_expansion_ at function end.
+ intptr_t survived_watermark = PromotedSpaceSizeOfObjects();
+
+ SelectScavengingVisitorsTable();
+
+ incremental_marking()->PrepareForScavenge();
+
+ // Flip the semispaces. After flipping, to space is empty, from space has
+ // live objects.
+ new_space_.Flip();
+ new_space_.ResetAllocationInfo();
+
+ // We need to sweep newly copied objects which can be either in the
+ // to space or promoted to the old generation. For to-space
+ // objects, we treat the bottom of the to space as a queue. Newly
+ // copied and unswept objects lie between a 'front' mark and the
+ // allocation pointer.
+ //
+ // Promoted objects can go into various old-generation spaces, and
+ // can be allocated internally in the spaces (from the free list).
+ // We treat the top of the to space as a queue of addresses of
+ // promoted objects. The addresses of newly promoted and unswept
+ // objects lie between a 'front' mark and a 'rear' mark that is
+ // updated as a side effect of promoting an object.
+ //
+ // There is guaranteed to be enough room at the top of the to space
+ // for the addresses of promoted objects: every object promoted
+ // frees up its size in bytes from the top of the new space, and
+ // objects are at least one pointer in size.
+ Address new_space_front = new_space_.ToSpaceStart();
+ promotion_queue_.Initialize();
+
+#ifdef DEBUG
+ store_buffer()->Clean();
+#endif
+
+ ScavengeVisitor scavenge_visitor(this);
+ // Copy roots.
+ IterateRoots(&scavenge_visitor, VISIT_ALL_IN_SCAVENGE);
+
+ // Copy objects reachable from the old generation.
+ {
+ StoreBufferRebuildScope scope(this, store_buffer(),
+ &ScavengeStoreBufferCallback);
+ store_buffer()->IteratePointersToNewSpace(&ScavengeObject);
+ }
+
+ // Copy objects reachable from simple cells by scavenging cell values
+ // directly.
+ HeapObjectIterator cell_iterator(cell_space_);
+ for (HeapObject* heap_object = cell_iterator.Next(); heap_object != NULL;
+ heap_object = cell_iterator.Next()) {
+ if (heap_object->IsCell()) {
+ Cell* cell = Cell::cast(heap_object);
+ Address value_address = cell->ValueAddress();
+ scavenge_visitor.VisitPointer(reinterpret_cast<Object**>(value_address));
+ }
+ }
+
+ // Copy objects reachable from global property cells by scavenging global
+ // property cell values directly.
+ HeapObjectIterator js_global_property_cell_iterator(property_cell_space_);
+ for (HeapObject* heap_object = js_global_property_cell_iterator.Next();
+ heap_object != NULL;
+ heap_object = js_global_property_cell_iterator.Next()) {
+ if (heap_object->IsPropertyCell()) {
+ PropertyCell* cell = PropertyCell::cast(heap_object);
+ Address value_address = cell->ValueAddress();
+ scavenge_visitor.VisitPointer(reinterpret_cast<Object**>(value_address));
+ Address type_address = cell->TypeAddress();
+ scavenge_visitor.VisitPointer(reinterpret_cast<Object**>(type_address));
+ }
+ }
+
+ // Copy objects reachable from the encountered weak collections list.
+ scavenge_visitor.VisitPointer(&encountered_weak_collections_);
+
+ // Copy objects reachable from the code flushing candidates list.
+ MarkCompactCollector* collector = mark_compact_collector();
+ if (collector->is_code_flushing_enabled()) {
+ collector->code_flusher()->IteratePointersToFromSpace(&scavenge_visitor);
+ }
+
+ new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+
+ while (isolate()->global_handles()->IterateObjectGroups(
+ &scavenge_visitor, &IsUnscavengedHeapObject)) {
+ new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+ }
+ isolate()->global_handles()->RemoveObjectGroups();
+ isolate()->global_handles()->RemoveImplicitRefGroups();
+
+ isolate_->global_handles()->IdentifyNewSpaceWeakIndependentHandles(
+ &IsUnscavengedHeapObject);
+ isolate_->global_handles()->IterateNewSpaceWeakIndependentRoots(
+ &scavenge_visitor);
+ new_space_front = DoScavenge(&scavenge_visitor, new_space_front);
+
+ UpdateNewSpaceReferencesInExternalStringTable(
+ &UpdateNewSpaceReferenceInExternalStringTableEntry);
+
+ promotion_queue_.Destroy();
+
+ incremental_marking()->UpdateMarkingDequeAfterScavenge();
+
+ ScavengeWeakObjectRetainer weak_object_retainer(this);
+ ProcessWeakReferences(&weak_object_retainer);
+
+ DCHECK(new_space_front == new_space_.top());
+
+ // Set age mark.
+ new_space_.set_age_mark(new_space_.top());
+
+ new_space_.LowerInlineAllocationLimit(
+ new_space_.inline_allocation_limit_step());
+
+ // Update how much has survived scavenge.
+ IncrementYoungSurvivorsCounter(static_cast<int>(
+ (PromotedSpaceSizeOfObjects() - survived_watermark) + new_space_.Size()));
+
+ LOG(isolate_, ResourceEvent("scavenge", "end"));
+
+ gc_state_ = NOT_IN_GC;
+
+ gc_idle_time_handler_.NotifyScavenge();
+}
+
+
+String* Heap::UpdateNewSpaceReferenceInExternalStringTableEntry(Heap* heap,
+ Object** p) {
+ MapWord first_word = HeapObject::cast(*p)->map_word();
+
+ if (!first_word.IsForwardingAddress()) {
+ // Unreachable external string can be finalized.
+ heap->FinalizeExternalString(String::cast(*p));
+ return NULL;
+ }
+
+ // String is still reachable.
+ return String::cast(first_word.ToForwardingAddress());
+}
+
+
+void Heap::UpdateNewSpaceReferencesInExternalStringTable(
+ ExternalStringTableUpdaterCallback updater_func) {
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ external_string_table_.Verify();
+ }
+#endif
+
+ if (external_string_table_.new_space_strings_.is_empty()) return;
+
+ Object** start = &external_string_table_.new_space_strings_[0];
+ Object** end = start + external_string_table_.new_space_strings_.length();
+ Object** last = start;
+
+ for (Object** p = start; p < end; ++p) {
+ DCHECK(InFromSpace(*p));
+ String* target = updater_func(this, p);
+
+ if (target == NULL) continue;
+
+ DCHECK(target->IsExternalString());
+
+ if (InNewSpace(target)) {
+ // String is still in new space. Update the table entry.
+ *last = target;
+ ++last;
+ } else {
+ // String got promoted. Move it to the old string list.
+ external_string_table_.AddOldString(target);
+ }
+ }
+
+ DCHECK(last <= end);
+ external_string_table_.ShrinkNewStrings(static_cast<int>(last - start));
+}
+
+
+void Heap::UpdateReferencesInExternalStringTable(
+ ExternalStringTableUpdaterCallback updater_func) {
+ // Update old space string references.
+ if (external_string_table_.old_space_strings_.length() > 0) {
+ Object** start = &external_string_table_.old_space_strings_[0];
+ Object** end = start + external_string_table_.old_space_strings_.length();
+ for (Object** p = start; p < end; ++p) *p = updater_func(this, p);
+ }
+
+ UpdateNewSpaceReferencesInExternalStringTable(updater_func);
+}
+
+
+void Heap::ProcessWeakReferences(WeakObjectRetainer* retainer) {
+ ProcessArrayBuffers(retainer);
+ ProcessNativeContexts(retainer);
+ // TODO(mvstanton): AllocationSites only need to be processed during
+ // MARK_COMPACT, as they live in old space. Verify and address.
+ ProcessAllocationSites(retainer);
+}
+
+
+void Heap::ProcessNativeContexts(WeakObjectRetainer* retainer) {
+ Object* head = VisitWeakList<Context>(this, native_contexts_list(), retainer);
+ // Update the head of the list of contexts.
+ set_native_contexts_list(head);
+}
+
+
+void Heap::ProcessArrayBuffers(WeakObjectRetainer* retainer) {
+ Object* array_buffer_obj =
+ VisitWeakList<JSArrayBuffer>(this, array_buffers_list(), retainer);
+ set_array_buffers_list(array_buffer_obj);
+}
+
+
+void Heap::TearDownArrayBuffers() {
+ Object* undefined = undefined_value();
+ for (Object* o = array_buffers_list(); o != undefined;) {
+ JSArrayBuffer* buffer = JSArrayBuffer::cast(o);
+ Runtime::FreeArrayBuffer(isolate(), buffer);
+ o = buffer->weak_next();
+ }
+ set_array_buffers_list(undefined);
+}
+
+
+void Heap::ProcessAllocationSites(WeakObjectRetainer* retainer) {
+ Object* allocation_site_obj =
+ VisitWeakList<AllocationSite>(this, allocation_sites_list(), retainer);
+ set_allocation_sites_list(allocation_site_obj);
+}
+
+
+void Heap::ResetAllAllocationSitesDependentCode(PretenureFlag flag) {
+ DisallowHeapAllocation no_allocation_scope;
+ Object* cur = allocation_sites_list();
+ bool marked = false;
+ while (cur->IsAllocationSite()) {
+ AllocationSite* casted = AllocationSite::cast(cur);
+ if (casted->GetPretenureMode() == flag) {
+ casted->ResetPretenureDecision();
+ casted->set_deopt_dependent_code(true);
+ marked = true;
+ }
+ cur = casted->weak_next();
+ }
+ if (marked) isolate_->stack_guard()->RequestDeoptMarkedAllocationSites();
+}
+
+
+void Heap::EvaluateOldSpaceLocalPretenuring(
+ uint64_t size_of_objects_before_gc) {
+ uint64_t size_of_objects_after_gc = SizeOfObjects();
+ double old_generation_survival_rate =
+ (static_cast<double>(size_of_objects_after_gc) * 100) /
+ static_cast<double>(size_of_objects_before_gc);
+
+ if (old_generation_survival_rate < kOldSurvivalRateLowThreshold) {
+ // Too many objects died in the old generation, pretenuring of wrong
+ // allocation sites may be the cause for that. We have to deopt all
+ // dependent code registered in the allocation sites to re-evaluate
+ // our pretenuring decisions.
+ ResetAllAllocationSitesDependentCode(TENURED);
+ if (FLAG_trace_pretenuring) {
+ PrintF(
+ "Deopt all allocation sites dependent code due to low survival "
+ "rate in the old generation %f\n",
+ old_generation_survival_rate);
+ }
+ }
+}
+
+
+void Heap::VisitExternalResources(v8::ExternalResourceVisitor* visitor) {
+ DisallowHeapAllocation no_allocation;
+ // All external strings are listed in the external string table.
+
+ class ExternalStringTableVisitorAdapter : public ObjectVisitor {
+ public:
+ explicit ExternalStringTableVisitorAdapter(
+ v8::ExternalResourceVisitor* visitor)
+ : visitor_(visitor) {}
+ virtual void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++) {
+ DCHECK((*p)->IsExternalString());
+ visitor_->VisitExternalString(
+ Utils::ToLocal(Handle<String>(String::cast(*p))));
+ }
+ }
+
+ private:
+ v8::ExternalResourceVisitor* visitor_;
+ } external_string_table_visitor(visitor);
+
+ external_string_table_.Iterate(&external_string_table_visitor);
+}
+
+
+class NewSpaceScavenger : public StaticNewSpaceVisitor<NewSpaceScavenger> {
+ public:
+ static inline void VisitPointer(Heap* heap, Object** p) {
+ Object* object = *p;
+ if (!heap->InNewSpace(object)) return;
+ Heap::ScavengeObject(reinterpret_cast<HeapObject**>(p),
+ reinterpret_cast<HeapObject*>(object));
+ }
+};
+
+
+Address Heap::DoScavenge(ObjectVisitor* scavenge_visitor,
+ Address new_space_front) {
+ do {
+ SemiSpace::AssertValidRange(new_space_front, new_space_.top());
+ // The addresses new_space_front and new_space_.top() define a
+ // queue of unprocessed copied objects. Process them until the
+ // queue is empty.
+ while (new_space_front != new_space_.top()) {
+ if (!NewSpacePage::IsAtEnd(new_space_front)) {
+ HeapObject* object = HeapObject::FromAddress(new_space_front);
+ new_space_front +=
+ NewSpaceScavenger::IterateBody(object->map(), object);
+ } else {
+ new_space_front =
+ NewSpacePage::FromLimit(new_space_front)->next_page()->area_start();
+ }
+ }
+
+ // Promote and process all the to-be-promoted objects.
+ {
+ StoreBufferRebuildScope scope(this, store_buffer(),
+ &ScavengeStoreBufferCallback);
+ while (!promotion_queue()->is_empty()) {
+ HeapObject* target;
+ int size;
+ promotion_queue()->remove(&target, &size);
+
+ // Promoted object might be already partially visited
+ // during old space pointer iteration. Thus we search specificly
+ // for pointers to from semispace instead of looking for pointers
+ // to new space.
+ DCHECK(!target->IsMap());
+ IterateAndMarkPointersToFromSpace(
+ target->address(), target->address() + size, &ScavengeObject);
+ }
+ }
+
+ // Take another spin if there are now unswept objects in new space
+ // (there are currently no more unswept promoted objects).
+ } while (new_space_front != new_space_.top());
+
+ return new_space_front;
+}
+
+
+STATIC_ASSERT((FixedDoubleArray::kHeaderSize & kDoubleAlignmentMask) ==
+ 0); // NOLINT
+STATIC_ASSERT((ConstantPoolArray::kFirstEntryOffset & kDoubleAlignmentMask) ==
+ 0); // NOLINT
+STATIC_ASSERT((ConstantPoolArray::kExtendedFirstOffset &
+ kDoubleAlignmentMask) == 0); // NOLINT
+
+
+INLINE(static HeapObject* EnsureDoubleAligned(Heap* heap, HeapObject* object,
+ int size));
+
+static HeapObject* EnsureDoubleAligned(Heap* heap, HeapObject* object,
+ int size) {
+ if ((OffsetFrom(object->address()) & kDoubleAlignmentMask) != 0) {
+ heap->CreateFillerObjectAt(object->address(), kPointerSize);
+ return HeapObject::FromAddress(object->address() + kPointerSize);
+ } else {
+ heap->CreateFillerObjectAt(object->address() + size - kPointerSize,
+ kPointerSize);
+ return object;
+ }
+}
+
+
+enum LoggingAndProfiling {
+ LOGGING_AND_PROFILING_ENABLED,
+ LOGGING_AND_PROFILING_DISABLED
+};
+
+
+enum MarksHandling { TRANSFER_MARKS, IGNORE_MARKS };
+
+
+template <MarksHandling marks_handling,
+ LoggingAndProfiling logging_and_profiling_mode>
+class ScavengingVisitor : public StaticVisitorBase {
+ public:
+ static void Initialize() {
+ table_.Register(kVisitSeqOneByteString, &EvacuateSeqOneByteString);
+ table_.Register(kVisitSeqTwoByteString, &EvacuateSeqTwoByteString);
+ table_.Register(kVisitShortcutCandidate, &EvacuateShortcutCandidate);
+ table_.Register(kVisitByteArray, &EvacuateByteArray);
+ table_.Register(kVisitFixedArray, &EvacuateFixedArray);
+ table_.Register(kVisitFixedDoubleArray, &EvacuateFixedDoubleArray);
+ table_.Register(kVisitFixedTypedArray, &EvacuateFixedTypedArray);
+ table_.Register(kVisitFixedFloat64Array, &EvacuateFixedFloat64Array);
+
+ table_.Register(
+ kVisitNativeContext,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
+ Context::kSize>);
+
+ table_.Register(
+ kVisitConsString,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
+ ConsString::kSize>);
+
+ table_.Register(
+ kVisitSlicedString,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
+ SlicedString::kSize>);
+
+ table_.Register(
+ kVisitSymbol,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
+ Symbol::kSize>);
+
+ table_.Register(
+ kVisitSharedFunctionInfo,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
+ SharedFunctionInfo::kSize>);
+
+ table_.Register(kVisitJSWeakCollection,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::Visit);
+
+ table_.Register(kVisitJSArrayBuffer,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::Visit);
+
+ table_.Register(kVisitJSTypedArray,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::Visit);
+
+ table_.Register(kVisitJSDataView,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::Visit);
+
+ table_.Register(kVisitJSRegExp,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::Visit);
+
+ if (marks_handling == IGNORE_MARKS) {
+ table_.Register(
+ kVisitJSFunction,
+ &ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
+ JSFunction::kSize>);
+ } else {
+ table_.Register(kVisitJSFunction, &EvacuateJSFunction);
+ }
+
+ table_.RegisterSpecializations<ObjectEvacuationStrategy<DATA_OBJECT>,
+ kVisitDataObject, kVisitDataObjectGeneric>();
+
+ table_.RegisterSpecializations<ObjectEvacuationStrategy<POINTER_OBJECT>,
+ kVisitJSObject, kVisitJSObjectGeneric>();
+
+ table_.RegisterSpecializations<ObjectEvacuationStrategy<POINTER_OBJECT>,
+ kVisitStruct, kVisitStructGeneric>();
+ }
+
+ static VisitorDispatchTable<ScavengingCallback>* GetTable() {
+ return &table_;
+ }
+
+ private:
+ enum ObjectContents { DATA_OBJECT, POINTER_OBJECT };
+
+ static void RecordCopiedObject(Heap* heap, HeapObject* obj) {
+ bool should_record = false;
+#ifdef DEBUG
+ should_record = FLAG_heap_stats;
+#endif
+ should_record = should_record || FLAG_log_gc;
+ if (should_record) {
+ if (heap->new_space()->Contains(obj)) {
+ heap->new_space()->RecordAllocation(obj);
+ } else {
+ heap->new_space()->RecordPromotion(obj);
+ }
+ }
+ }
+
+ // Helper function used by CopyObject to copy a source object to an
+ // allocated target object and update the forwarding pointer in the source
+ // object. Returns the target object.
+ INLINE(static void MigrateObject(Heap* heap, HeapObject* source,
+ HeapObject* target, int size)) {
+ // If we migrate into to-space, then the to-space top pointer should be
+ // right after the target object. Incorporate double alignment
+ // over-allocation.
+ DCHECK(!heap->InToSpace(target) ||
+ target->address() + size == heap->new_space()->top() ||
+ target->address() + size + kPointerSize == heap->new_space()->top());
+
+ // Make sure that we do not overwrite the promotion queue which is at
+ // the end of to-space.
+ DCHECK(!heap->InToSpace(target) ||
+ heap->promotion_queue()->IsBelowPromotionQueue(
+ heap->new_space()->top()));
+
+ // Copy the content of source to target.
+ heap->CopyBlock(target->address(), source->address(), size);
+
+ // Set the forwarding address.
+ source->set_map_word(MapWord::FromForwardingAddress(target));
+
+ if (logging_and_profiling_mode == LOGGING_AND_PROFILING_ENABLED) {
+ // Update NewSpace stats if necessary.
+ RecordCopiedObject(heap, target);
+ heap->OnMoveEvent(target, source, size);
+ }
+
+ if (marks_handling == TRANSFER_MARKS) {
+ if (Marking::TransferColor(source, target)) {
+ MemoryChunk::IncrementLiveBytesFromGC(target->address(), size);
+ }
+ }
+ }
+
+ template <int alignment>
+ static inline bool SemiSpaceCopyObject(Map* map, HeapObject** slot,
+ HeapObject* object, int object_size) {
+ Heap* heap = map->GetHeap();
+
+ int allocation_size = object_size;
+ if (alignment != kObjectAlignment) {
+ DCHECK(alignment == kDoubleAlignment);
+ allocation_size += kPointerSize;
+ }
+
+ DCHECK(heap->AllowedToBeMigrated(object, NEW_SPACE));
+ AllocationResult allocation =
+ heap->new_space()->AllocateRaw(allocation_size);
+
+ HeapObject* target = NULL; // Initialization to please compiler.
+ if (allocation.To(&target)) {
+ // Order is important here: Set the promotion limit before storing a
+ // filler for double alignment or migrating the object. Otherwise we
+ // may end up overwriting promotion queue entries when we migrate the
+ // object.
+ heap->promotion_queue()->SetNewLimit(heap->new_space()->top());
+
+ if (alignment != kObjectAlignment) {
+ target = EnsureDoubleAligned(heap, target, allocation_size);
+ }
+
+ // Order is important: slot might be inside of the target if target
+ // was allocated over a dead object and slot comes from the store
+ // buffer.
+ *slot = target;
+ MigrateObject(heap, object, target, object_size);
+
+ heap->IncrementSemiSpaceCopiedObjectSize(object_size);
+ return true;
+ }
+ return false;
+ }
+
+
+ template <ObjectContents object_contents, int alignment>
+ static inline bool PromoteObject(Map* map, HeapObject** slot,
+ HeapObject* object, int object_size) {
+ Heap* heap = map->GetHeap();
+
+ int allocation_size = object_size;
+ if (alignment != kObjectAlignment) {
+ DCHECK(alignment == kDoubleAlignment);
+ allocation_size += kPointerSize;
+ }
+
+ AllocationResult allocation;
+ if (object_contents == DATA_OBJECT) {
+ DCHECK(heap->AllowedToBeMigrated(object, OLD_DATA_SPACE));
+ allocation = heap->old_data_space()->AllocateRaw(allocation_size);
+ } else {
+ DCHECK(heap->AllowedToBeMigrated(object, OLD_POINTER_SPACE));
+ allocation = heap->old_pointer_space()->AllocateRaw(allocation_size);
+ }
+
+ HeapObject* target = NULL; // Initialization to please compiler.
+ if (allocation.To(&target)) {
+ if (alignment != kObjectAlignment) {
+ target = EnsureDoubleAligned(heap, target, allocation_size);
+ }
+
+ // Order is important: slot might be inside of the target if target
+ // was allocated over a dead object and slot comes from the store
+ // buffer.
+ *slot = target;
+ MigrateObject(heap, object, target, object_size);
+
+ if (object_contents == POINTER_OBJECT) {
+ if (map->instance_type() == JS_FUNCTION_TYPE) {
+ heap->promotion_queue()->insert(target,
+ JSFunction::kNonWeakFieldsEndOffset);
+ } else {
+ heap->promotion_queue()->insert(target, object_size);
+ }
+ }
+ heap->IncrementPromotedObjectsSize(object_size);
+ return true;
+ }
+ return false;
+ }
+
+
+ template <ObjectContents object_contents, int alignment>
+ static inline void EvacuateObject(Map* map, HeapObject** slot,
+ HeapObject* object, int object_size) {
+ SLOW_DCHECK(object_size <= Page::kMaxRegularHeapObjectSize);
+ SLOW_DCHECK(object->Size() == object_size);
+ Heap* heap = map->GetHeap();
+
+ if (!heap->ShouldBePromoted(object->address(), object_size)) {
+ // A semi-space copy may fail due to fragmentation. In that case, we
+ // try to promote the object.
+ if (SemiSpaceCopyObject<alignment>(map, slot, object, object_size)) {
+ return;
+ }
+ }
+
+ if (PromoteObject<object_contents, alignment>(map, slot, object,
+ object_size)) {
+ return;
+ }
+
+ // If promotion failed, we try to copy the object to the other semi-space
+ if (SemiSpaceCopyObject<alignment>(map, slot, object, object_size)) return;
+
+ UNREACHABLE();
+ }
+
+
+ static inline void EvacuateJSFunction(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ ObjectEvacuationStrategy<POINTER_OBJECT>::template VisitSpecialized<
+ JSFunction::kSize>(map, slot, object);
+
+ MapWord map_word = object->map_word();
+ DCHECK(map_word.IsForwardingAddress());
+ HeapObject* target = map_word.ToForwardingAddress();
+
+ MarkBit mark_bit = Marking::MarkBitFrom(target);
+ if (Marking::IsBlack(mark_bit)) {
+ // This object is black and it might not be rescanned by marker.
+ // We should explicitly record code entry slot for compaction because
+ // promotion queue processing (IterateAndMarkPointersToFromSpace) will
+ // miss it as it is not HeapObject-tagged.
+ Address code_entry_slot =
+ target->address() + JSFunction::kCodeEntryOffset;
+ Code* code = Code::cast(Code::GetObjectFromEntryAddress(code_entry_slot));
+ map->GetHeap()->mark_compact_collector()->RecordCodeEntrySlot(
+ code_entry_slot, code);
+ }
+ }
+
+
+ static inline void EvacuateFixedArray(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ int object_size = FixedArray::BodyDescriptor::SizeOf(map, object);
+ EvacuateObject<POINTER_OBJECT, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+
+
+ static inline void EvacuateFixedDoubleArray(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ int length = reinterpret_cast<FixedDoubleArray*>(object)->length();
+ int object_size = FixedDoubleArray::SizeFor(length);
+ EvacuateObject<DATA_OBJECT, kDoubleAlignment>(map, slot, object,
+ object_size);
+ }
+
+
+ static inline void EvacuateFixedTypedArray(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ int object_size = reinterpret_cast<FixedTypedArrayBase*>(object)->size();
+ EvacuateObject<DATA_OBJECT, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+
+
+ static inline void EvacuateFixedFloat64Array(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ int object_size = reinterpret_cast<FixedFloat64Array*>(object)->size();
+ EvacuateObject<DATA_OBJECT, kDoubleAlignment>(map, slot, object,
+ object_size);
+ }
+
+
+ static inline void EvacuateByteArray(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ int object_size = reinterpret_cast<ByteArray*>(object)->ByteArraySize();
+ EvacuateObject<DATA_OBJECT, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+
+
+ static inline void EvacuateSeqOneByteString(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ int object_size = SeqOneByteString::cast(object)
+ ->SeqOneByteStringSize(map->instance_type());
+ EvacuateObject<DATA_OBJECT, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+
+
+ static inline void EvacuateSeqTwoByteString(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ int object_size = SeqTwoByteString::cast(object)
+ ->SeqTwoByteStringSize(map->instance_type());
+ EvacuateObject<DATA_OBJECT, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+
+
+ static inline void EvacuateShortcutCandidate(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ DCHECK(IsShortcutCandidate(map->instance_type()));
+
+ Heap* heap = map->GetHeap();
+
+ if (marks_handling == IGNORE_MARKS &&
+ ConsString::cast(object)->unchecked_second() == heap->empty_string()) {
+ HeapObject* first =
+ HeapObject::cast(ConsString::cast(object)->unchecked_first());
+
+ *slot = first;
+
+ if (!heap->InNewSpace(first)) {
+ object->set_map_word(MapWord::FromForwardingAddress(first));
+ return;
+ }
+
+ MapWord first_word = first->map_word();
+ if (first_word.IsForwardingAddress()) {
+ HeapObject* target = first_word.ToForwardingAddress();
+
+ *slot = target;
+ object->set_map_word(MapWord::FromForwardingAddress(target));
+ return;
+ }
+
+ heap->DoScavengeObject(first->map(), slot, first);
+ object->set_map_word(MapWord::FromForwardingAddress(*slot));
+ return;
+ }
+
+ int object_size = ConsString::kSize;
+ EvacuateObject<POINTER_OBJECT, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+
+ template <ObjectContents object_contents>
+ class ObjectEvacuationStrategy {
+ public:
+ template <int object_size>
+ static inline void VisitSpecialized(Map* map, HeapObject** slot,
+ HeapObject* object) {
+ EvacuateObject<object_contents, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+
+ static inline void Visit(Map* map, HeapObject** slot, HeapObject* object) {
+ int object_size = map->instance_size();
+ EvacuateObject<object_contents, kObjectAlignment>(map, slot, object,
+ object_size);
+ }
+ };
+
+ static VisitorDispatchTable<ScavengingCallback> table_;
+};
+
+
+template <MarksHandling marks_handling,
+ LoggingAndProfiling logging_and_profiling_mode>
+VisitorDispatchTable<ScavengingCallback>
+ ScavengingVisitor<marks_handling, logging_and_profiling_mode>::table_;
+
+
+static void InitializeScavengingVisitorsTables() {
+ ScavengingVisitor<TRANSFER_MARKS,
+ LOGGING_AND_PROFILING_DISABLED>::Initialize();
+ ScavengingVisitor<IGNORE_MARKS, LOGGING_AND_PROFILING_DISABLED>::Initialize();
+ ScavengingVisitor<TRANSFER_MARKS,
+ LOGGING_AND_PROFILING_ENABLED>::Initialize();
+ ScavengingVisitor<IGNORE_MARKS, LOGGING_AND_PROFILING_ENABLED>::Initialize();
+}
+
+
+void Heap::SelectScavengingVisitorsTable() {
+ bool logging_and_profiling =
+ FLAG_verify_predictable || isolate()->logger()->is_logging() ||
+ isolate()->cpu_profiler()->is_profiling() ||
+ (isolate()->heap_profiler() != NULL &&
+ isolate()->heap_profiler()->is_tracking_object_moves());
+
+ if (!incremental_marking()->IsMarking()) {
+ if (!logging_and_profiling) {
+ scavenging_visitors_table_.CopyFrom(ScavengingVisitor<
+ IGNORE_MARKS, LOGGING_AND_PROFILING_DISABLED>::GetTable());
+ } else {
+ scavenging_visitors_table_.CopyFrom(ScavengingVisitor<
+ IGNORE_MARKS, LOGGING_AND_PROFILING_ENABLED>::GetTable());
+ }
+ } else {
+ if (!logging_and_profiling) {
+ scavenging_visitors_table_.CopyFrom(ScavengingVisitor<
+ TRANSFER_MARKS, LOGGING_AND_PROFILING_DISABLED>::GetTable());
+ } else {
+ scavenging_visitors_table_.CopyFrom(ScavengingVisitor<
+ TRANSFER_MARKS, LOGGING_AND_PROFILING_ENABLED>::GetTable());
+ }
+
+ if (incremental_marking()->IsCompacting()) {
+ // When compacting forbid short-circuiting of cons-strings.
+ // Scavenging code relies on the fact that new space object
+ // can't be evacuated into evacuation candidate but
+ // short-circuiting violates this assumption.
+ scavenging_visitors_table_.Register(
+ StaticVisitorBase::kVisitShortcutCandidate,
+ scavenging_visitors_table_.GetVisitorById(
+ StaticVisitorBase::kVisitConsString));
+ }
+ }
+}
+
+
+void Heap::ScavengeObjectSlow(HeapObject** p, HeapObject* object) {
+ SLOW_DCHECK(object->GetIsolate()->heap()->InFromSpace(object));
+ MapWord first_word = object->map_word();
+ SLOW_DCHECK(!first_word.IsForwardingAddress());
+ Map* map = first_word.ToMap();
+ map->GetHeap()->DoScavengeObject(map, p, object);
+}
+
+
+AllocationResult Heap::AllocatePartialMap(InstanceType instance_type,
+ int instance_size) {
+ Object* result;
+ AllocationResult allocation = AllocateRaw(Map::kSize, MAP_SPACE, MAP_SPACE);
+ if (!allocation.To(&result)) return allocation;
+
+ // Map::cast cannot be used due to uninitialized map field.
+ reinterpret_cast<Map*>(result)->set_map(raw_unchecked_meta_map());
+ reinterpret_cast<Map*>(result)->set_instance_type(instance_type);
+ reinterpret_cast<Map*>(result)->set_instance_size(instance_size);
+ reinterpret_cast<Map*>(result)->set_visitor_id(
+ StaticVisitorBase::GetVisitorId(instance_type, instance_size));
+ reinterpret_cast<Map*>(result)->set_inobject_properties(0);
+ reinterpret_cast<Map*>(result)->set_pre_allocated_property_fields(0);
+ reinterpret_cast<Map*>(result)->set_unused_property_fields(0);
+ reinterpret_cast<Map*>(result)->set_bit_field(0);
+ reinterpret_cast<Map*>(result)->set_bit_field2(0);
+ int bit_field3 = Map::EnumLengthBits::encode(kInvalidEnumCacheSentinel) |
+ Map::OwnsDescriptors::encode(true);
+ reinterpret_cast<Map*>(result)->set_bit_field3(bit_field3);
+ return result;
+}
+
+
+AllocationResult Heap::AllocateMap(InstanceType instance_type,
+ int instance_size,
+ ElementsKind elements_kind) {
+ HeapObject* result;
+ AllocationResult allocation = AllocateRaw(Map::kSize, MAP_SPACE, MAP_SPACE);
+ if (!allocation.To(&result)) return allocation;
+
+ result->set_map_no_write_barrier(meta_map());
+ Map* map = Map::cast(result);
+ map->set_instance_type(instance_type);
+ map->set_visitor_id(
+ StaticVisitorBase::GetVisitorId(instance_type, instance_size));
+ map->set_prototype(null_value(), SKIP_WRITE_BARRIER);
+ map->set_constructor(null_value(), SKIP_WRITE_BARRIER);
+ map->set_instance_size(instance_size);
+ map->set_inobject_properties(0);
+ map->set_pre_allocated_property_fields(0);
+ map->set_code_cache(empty_fixed_array(), SKIP_WRITE_BARRIER);
+ map->set_dependent_code(DependentCode::cast(empty_fixed_array()),
+ SKIP_WRITE_BARRIER);
+ map->init_back_pointer(undefined_value());
+ map->set_unused_property_fields(0);
+ map->set_instance_descriptors(empty_descriptor_array());
+ map->set_bit_field(0);
+ map->set_bit_field2(1 << Map::kIsExtensible);
+ int bit_field3 = Map::EnumLengthBits::encode(kInvalidEnumCacheSentinel) |
+ Map::OwnsDescriptors::encode(true);
+ map->set_bit_field3(bit_field3);
+ map->set_elements_kind(elements_kind);
+
+ return map;
+}
+
+
+AllocationResult Heap::AllocateFillerObject(int size, bool double_align,
+ AllocationSpace space) {
+ HeapObject* obj;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, space);
+ if (!allocation.To(&obj)) return allocation;
+ }
+#ifdef DEBUG
+ MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
+ DCHECK(chunk->owner()->identity() == space);
+#endif
+ CreateFillerObjectAt(obj->address(), size);
+ return obj;
+}
+
+
+const Heap::StringTypeTable Heap::string_type_table[] = {
+#define STRING_TYPE_ELEMENT(type, size, name, camel_name) \
+ { type, size, k##camel_name##MapRootIndex } \
+ ,
+ STRING_TYPE_LIST(STRING_TYPE_ELEMENT)
+#undef STRING_TYPE_ELEMENT
+};
+
+
+const Heap::ConstantStringTable Heap::constant_string_table[] = {
+#define CONSTANT_STRING_ELEMENT(name, contents) \
+ { contents, k##name##RootIndex } \
+ ,
+ INTERNALIZED_STRING_LIST(CONSTANT_STRING_ELEMENT)
+#undef CONSTANT_STRING_ELEMENT
+};
+
+
+const Heap::StructTable Heap::struct_table[] = {
+#define STRUCT_TABLE_ELEMENT(NAME, Name, name) \
+ { NAME##_TYPE, Name::kSize, k##Name##MapRootIndex } \
+ ,
+ STRUCT_LIST(STRUCT_TABLE_ELEMENT)
+#undef STRUCT_TABLE_ELEMENT
+};
+
+
+bool Heap::CreateInitialMaps() {
+ HeapObject* obj;
+ {
+ AllocationResult allocation = AllocatePartialMap(MAP_TYPE, Map::kSize);
+ if (!allocation.To(&obj)) return false;
+ }
+ // Map::cast cannot be used due to uninitialized map field.
+ Map* new_meta_map = reinterpret_cast<Map*>(obj);
+ set_meta_map(new_meta_map);
+ new_meta_map->set_map(new_meta_map);
+
+ { // Partial map allocation
+#define ALLOCATE_PARTIAL_MAP(instance_type, size, field_name) \
+ { \
+ Map* map; \
+ if (!AllocatePartialMap((instance_type), (size)).To(&map)) return false; \
+ set_##field_name##_map(map); \
+ }
+
+ ALLOCATE_PARTIAL_MAP(FIXED_ARRAY_TYPE, kVariableSizeSentinel, fixed_array);
+ ALLOCATE_PARTIAL_MAP(ODDBALL_TYPE, Oddball::kSize, undefined);
+ ALLOCATE_PARTIAL_MAP(ODDBALL_TYPE, Oddball::kSize, null);
+ ALLOCATE_PARTIAL_MAP(CONSTANT_POOL_ARRAY_TYPE, kVariableSizeSentinel,
+ constant_pool_array);
+
+#undef ALLOCATE_PARTIAL_MAP
+ }
+
+ // Allocate the empty array.
+ {
+ AllocationResult allocation = AllocateEmptyFixedArray();
+ if (!allocation.To(&obj)) return false;
+ }
+ set_empty_fixed_array(FixedArray::cast(obj));
+
+ {
+ AllocationResult allocation = Allocate(null_map(), OLD_POINTER_SPACE);
+ if (!allocation.To(&obj)) return false;
+ }
+ set_null_value(Oddball::cast(obj));
+ Oddball::cast(obj)->set_kind(Oddball::kNull);
+
+ {
+ AllocationResult allocation = Allocate(undefined_map(), OLD_POINTER_SPACE);
+ if (!allocation.To(&obj)) return false;
+ }
+ set_undefined_value(Oddball::cast(obj));
+ Oddball::cast(obj)->set_kind(Oddball::kUndefined);
+ DCHECK(!InNewSpace(undefined_value()));
+
+ // Set preliminary exception sentinel value before actually initializing it.
+ set_exception(null_value());
+
+ // Allocate the empty descriptor array.
+ {
+ AllocationResult allocation = AllocateEmptyFixedArray();
+ if (!allocation.To(&obj)) return false;
+ }
+ set_empty_descriptor_array(DescriptorArray::cast(obj));
+
+ // Allocate the constant pool array.
+ {
+ AllocationResult allocation = AllocateEmptyConstantPoolArray();
+ if (!allocation.To(&obj)) return false;
+ }
+ set_empty_constant_pool_array(ConstantPoolArray::cast(obj));
+
+ // Fix the instance_descriptors for the existing maps.
+ meta_map()->set_code_cache(empty_fixed_array());
+ meta_map()->set_dependent_code(DependentCode::cast(empty_fixed_array()));
+ meta_map()->init_back_pointer(undefined_value());
+ meta_map()->set_instance_descriptors(empty_descriptor_array());
+
+ fixed_array_map()->set_code_cache(empty_fixed_array());
+ fixed_array_map()->set_dependent_code(
+ DependentCode::cast(empty_fixed_array()));
+ fixed_array_map()->init_back_pointer(undefined_value());
+ fixed_array_map()->set_instance_descriptors(empty_descriptor_array());
+
+ undefined_map()->set_code_cache(empty_fixed_array());
+ undefined_map()->set_dependent_code(DependentCode::cast(empty_fixed_array()));
+ undefined_map()->init_back_pointer(undefined_value());
+ undefined_map()->set_instance_descriptors(empty_descriptor_array());
+
+ null_map()->set_code_cache(empty_fixed_array());
+ null_map()->set_dependent_code(DependentCode::cast(empty_fixed_array()));
+ null_map()->init_back_pointer(undefined_value());
+ null_map()->set_instance_descriptors(empty_descriptor_array());
+
+ constant_pool_array_map()->set_code_cache(empty_fixed_array());
+ constant_pool_array_map()->set_dependent_code(
+ DependentCode::cast(empty_fixed_array()));
+ constant_pool_array_map()->init_back_pointer(undefined_value());
+ constant_pool_array_map()->set_instance_descriptors(empty_descriptor_array());
+
+ // Fix prototype object for existing maps.
+ meta_map()->set_prototype(null_value());
+ meta_map()->set_constructor(null_value());
+
+ fixed_array_map()->set_prototype(null_value());
+ fixed_array_map()->set_constructor(null_value());
+
+ undefined_map()->set_prototype(null_value());
+ undefined_map()->set_constructor(null_value());
+
+ null_map()->set_prototype(null_value());
+ null_map()->set_constructor(null_value());
+
+ constant_pool_array_map()->set_prototype(null_value());
+ constant_pool_array_map()->set_constructor(null_value());
+
+ { // Map allocation
+#define ALLOCATE_MAP(instance_type, size, field_name) \
+ { \
+ Map* map; \
+ if (!AllocateMap((instance_type), size).To(&map)) return false; \
+ set_##field_name##_map(map); \
+ }
+
+#define ALLOCATE_VARSIZE_MAP(instance_type, field_name) \
+ ALLOCATE_MAP(instance_type, kVariableSizeSentinel, field_name)
+
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, fixed_cow_array)
+ DCHECK(fixed_array_map() != fixed_cow_array_map());
+
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, scope_info)
+ ALLOCATE_MAP(HEAP_NUMBER_TYPE, HeapNumber::kSize, heap_number)
+ ALLOCATE_MAP(MUTABLE_HEAP_NUMBER_TYPE, HeapNumber::kSize,
+ mutable_heap_number)
+ ALLOCATE_MAP(SYMBOL_TYPE, Symbol::kSize, symbol)
+ ALLOCATE_MAP(FOREIGN_TYPE, Foreign::kSize, foreign)
+
+ ALLOCATE_MAP(ODDBALL_TYPE, Oddball::kSize, the_hole);
+ ALLOCATE_MAP(ODDBALL_TYPE, Oddball::kSize, boolean);
+ ALLOCATE_MAP(ODDBALL_TYPE, Oddball::kSize, uninitialized);
+ ALLOCATE_MAP(ODDBALL_TYPE, Oddball::kSize, arguments_marker);
+ ALLOCATE_MAP(ODDBALL_TYPE, Oddball::kSize, no_interceptor_result_sentinel);
+ ALLOCATE_MAP(ODDBALL_TYPE, Oddball::kSize, exception);
+ ALLOCATE_MAP(ODDBALL_TYPE, Oddball::kSize, termination_exception);
+
+ for (unsigned i = 0; i < arraysize(string_type_table); i++) {
+ const StringTypeTable& entry = string_type_table[i];
+ {
+ AllocationResult allocation = AllocateMap(entry.type, entry.size);
+ if (!allocation.To(&obj)) return false;
+ }
+ // Mark cons string maps as unstable, because their objects can change
+ // maps during GC.
+ Map* map = Map::cast(obj);
+ if (StringShape(entry.type).IsCons()) map->mark_unstable();
+ roots_[entry.index] = map;
+ }
+
+ ALLOCATE_VARSIZE_MAP(STRING_TYPE, undetectable_string)
+ undetectable_string_map()->set_is_undetectable();
+
+ ALLOCATE_VARSIZE_MAP(ONE_BYTE_STRING_TYPE, undetectable_one_byte_string);
+ undetectable_one_byte_string_map()->set_is_undetectable();
+
+ ALLOCATE_VARSIZE_MAP(FIXED_DOUBLE_ARRAY_TYPE, fixed_double_array)
+ ALLOCATE_VARSIZE_MAP(BYTE_ARRAY_TYPE, byte_array)
+ ALLOCATE_VARSIZE_MAP(FREE_SPACE_TYPE, free_space)
+
+#define ALLOCATE_EXTERNAL_ARRAY_MAP(Type, type, TYPE, ctype, size) \
+ ALLOCATE_MAP(EXTERNAL_##TYPE##_ARRAY_TYPE, ExternalArray::kAlignedSize, \
+ external_##type##_array)
+
+ TYPED_ARRAYS(ALLOCATE_EXTERNAL_ARRAY_MAP)
+#undef ALLOCATE_EXTERNAL_ARRAY_MAP
+
+#define ALLOCATE_FIXED_TYPED_ARRAY_MAP(Type, type, TYPE, ctype, size) \
+ ALLOCATE_VARSIZE_MAP(FIXED_##TYPE##_ARRAY_TYPE, fixed_##type##_array)
+
+ TYPED_ARRAYS(ALLOCATE_FIXED_TYPED_ARRAY_MAP)
+#undef ALLOCATE_FIXED_TYPED_ARRAY_MAP
+
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, sloppy_arguments_elements)
+
+ ALLOCATE_VARSIZE_MAP(CODE_TYPE, code)
+
+ ALLOCATE_MAP(CELL_TYPE, Cell::kSize, cell)
+ ALLOCATE_MAP(PROPERTY_CELL_TYPE, PropertyCell::kSize, global_property_cell)
+ ALLOCATE_MAP(FILLER_TYPE, kPointerSize, one_pointer_filler)
+ ALLOCATE_MAP(FILLER_TYPE, 2 * kPointerSize, two_pointer_filler)
+
+
+ for (unsigned i = 0; i < arraysize(struct_table); i++) {
+ const StructTable& entry = struct_table[i];
+ Map* map;
+ if (!AllocateMap(entry.type, entry.size).To(&map)) return false;
+ roots_[entry.index] = map;
+ }
+
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, hash_table)
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, ordered_hash_table)
+
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, function_context)
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, catch_context)
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, with_context)
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, block_context)
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, module_context)
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, global_context)
+
+ ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, native_context)
+ native_context_map()->set_dictionary_map(true);
+ native_context_map()->set_visitor_id(
+ StaticVisitorBase::kVisitNativeContext);
+
+ ALLOCATE_MAP(SHARED_FUNCTION_INFO_TYPE, SharedFunctionInfo::kAlignedSize,
+ shared_function_info)
+
+ ALLOCATE_MAP(JS_MESSAGE_OBJECT_TYPE, JSMessageObject::kSize, message_object)
+ ALLOCATE_MAP(JS_OBJECT_TYPE, JSObject::kHeaderSize + kPointerSize, external)
+ external_map()->set_is_extensible(false);
+#undef ALLOCATE_VARSIZE_MAP
+#undef ALLOCATE_MAP
+ }
+
+ { // Empty arrays
+ {
+ ByteArray* byte_array;
+ if (!AllocateByteArray(0, TENURED).To(&byte_array)) return false;
+ set_empty_byte_array(byte_array);
+ }
+
+#define ALLOCATE_EMPTY_EXTERNAL_ARRAY(Type, type, TYPE, ctype, size) \
+ { \
+ ExternalArray* obj; \
+ if (!AllocateEmptyExternalArray(kExternal##Type##Array).To(&obj)) \
+ return false; \
+ set_empty_external_##type##_array(obj); \
+ }
+
+ TYPED_ARRAYS(ALLOCATE_EMPTY_EXTERNAL_ARRAY)
+#undef ALLOCATE_EMPTY_EXTERNAL_ARRAY
+
+#define ALLOCATE_EMPTY_FIXED_TYPED_ARRAY(Type, type, TYPE, ctype, size) \
+ { \
+ FixedTypedArrayBase* obj; \
+ if (!AllocateEmptyFixedTypedArray(kExternal##Type##Array).To(&obj)) \
+ return false; \
+ set_empty_fixed_##type##_array(obj); \
+ }
+
+ TYPED_ARRAYS(ALLOCATE_EMPTY_FIXED_TYPED_ARRAY)
+#undef ALLOCATE_EMPTY_FIXED_TYPED_ARRAY
+ }
+ DCHECK(!InNewSpace(empty_fixed_array()));
+ return true;
+}
+
+
+AllocationResult Heap::AllocateHeapNumber(double value, MutableMode mode,
+ PretenureFlag pretenure) {
+ // Statically ensure that it is safe to allocate heap numbers in paged
+ // spaces.
+ int size = HeapNumber::kSize;
+ STATIC_ASSERT(HeapNumber::kSize <= Page::kMaxRegularHeapObjectSize);
+
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, pretenure);
+
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ Map* map = mode == MUTABLE ? mutable_heap_number_map() : heap_number_map();
+ HeapObject::cast(result)->set_map_no_write_barrier(map);
+ HeapNumber::cast(result)->set_value(value);
+ return result;
+}
+
+
+AllocationResult Heap::AllocateCell(Object* value) {
+ int size = Cell::kSize;
+ STATIC_ASSERT(Cell::kSize <= Page::kMaxRegularHeapObjectSize);
+
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, CELL_SPACE, CELL_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+ result->set_map_no_write_barrier(cell_map());
+ Cell::cast(result)->set_value(value);
+ return result;
+}
+
+
+AllocationResult Heap::AllocatePropertyCell() {
+ int size = PropertyCell::kSize;
+ STATIC_ASSERT(PropertyCell::kSize <= Page::kMaxRegularHeapObjectSize);
+
+ HeapObject* result;
+ AllocationResult allocation =
+ AllocateRaw(size, PROPERTY_CELL_SPACE, PROPERTY_CELL_SPACE);
+ if (!allocation.To(&result)) return allocation;
+
+ result->set_map_no_write_barrier(global_property_cell_map());
+ PropertyCell* cell = PropertyCell::cast(result);
+ cell->set_dependent_code(DependentCode::cast(empty_fixed_array()),
+ SKIP_WRITE_BARRIER);
+ cell->set_value(the_hole_value());
+ cell->set_type(HeapType::None());
+ return result;
+}
+
+
+void Heap::CreateApiObjects() {
+ HandleScope scope(isolate());
+ Factory* factory = isolate()->factory();
+ Handle<Map> new_neander_map =
+ factory->NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize);
+
+ // Don't use Smi-only elements optimizations for objects with the neander
+ // map. There are too many cases where element values are set directly with a
+ // bottleneck to trap the Smi-only -> fast elements transition, and there
+ // appears to be no benefit for optimize this case.
+ new_neander_map->set_elements_kind(TERMINAL_FAST_ELEMENTS_KIND);
+ set_neander_map(*new_neander_map);
+
+ Handle<JSObject> listeners = factory->NewNeanderObject();
+ Handle<FixedArray> elements = factory->NewFixedArray(2);
+ elements->set(0, Smi::FromInt(0));
+ listeners->set_elements(*elements);
+ set_message_listeners(*listeners);
+}
+
+
+void Heap::CreateJSEntryStub() {
+ JSEntryStub stub(isolate(), StackFrame::ENTRY);
+ set_js_entry_code(*stub.GetCode());
+}
+
+
+void Heap::CreateJSConstructEntryStub() {
+ JSEntryStub stub(isolate(), StackFrame::ENTRY_CONSTRUCT);
+ set_js_construct_entry_code(*stub.GetCode());
+}
+
+
+void Heap::CreateFixedStubs() {
+ // Here we create roots for fixed stubs. They are needed at GC
+ // for cooking and uncooking (check out frames.cc).
+ // The eliminates the need for doing dictionary lookup in the
+ // stub cache for these stubs.
+ HandleScope scope(isolate());
+
+ // Create stubs that should be there, so we don't unexpectedly have to
+ // create them if we need them during the creation of another stub.
+ // Stub creation mixes raw pointers and handles in an unsafe manner so
+ // we cannot create stubs while we are creating stubs.
+ CodeStub::GenerateStubsAheadOfTime(isolate());
+
+ // MacroAssembler::Abort calls (usually enabled with --debug-code) depend on
+ // CEntryStub, so we need to call GenerateStubsAheadOfTime before JSEntryStub
+ // is created.
+
+ // gcc-4.4 has problem generating correct code of following snippet:
+ // { JSEntryStub stub;
+ // js_entry_code_ = *stub.GetCode();
+ // }
+ // { JSConstructEntryStub stub;
+ // js_construct_entry_code_ = *stub.GetCode();
+ // }
+ // To workaround the problem, make separate functions without inlining.
+ Heap::CreateJSEntryStub();
+ Heap::CreateJSConstructEntryStub();
+}
+
+
+void Heap::CreateInitialObjects() {
+ HandleScope scope(isolate());
+ Factory* factory = isolate()->factory();
+
+ // The -0 value must be set before NewNumber works.
+ set_minus_zero_value(*factory->NewHeapNumber(-0.0, IMMUTABLE, TENURED));
+ DCHECK(std::signbit(minus_zero_value()->Number()) != 0);
+
+ set_nan_value(
+ *factory->NewHeapNumber(base::OS::nan_value(), IMMUTABLE, TENURED));
+ set_infinity_value(*factory->NewHeapNumber(V8_INFINITY, IMMUTABLE, TENURED));
+
+ // The hole has not been created yet, but we want to put something
+ // predictable in the gaps in the string table, so lets make that Smi zero.
+ set_the_hole_value(reinterpret_cast<Oddball*>(Smi::FromInt(0)));
+
+ // Allocate initial string table.
+ set_string_table(*StringTable::New(isolate(), kInitialStringTableSize));
+
+ // Finish initializing oddballs after creating the string table.
+ Oddball::Initialize(isolate(), factory->undefined_value(), "undefined",
+ factory->nan_value(), Oddball::kUndefined);
+
+ // Initialize the null_value.
+ Oddball::Initialize(isolate(), factory->null_value(), "null",
+ handle(Smi::FromInt(0), isolate()), Oddball::kNull);
+
+ set_true_value(*factory->NewOddball(factory->boolean_map(), "true",
+ handle(Smi::FromInt(1), isolate()),
+ Oddball::kTrue));
+
+ set_false_value(*factory->NewOddball(factory->boolean_map(), "false",
+ handle(Smi::FromInt(0), isolate()),
+ Oddball::kFalse));
+
+ set_the_hole_value(*factory->NewOddball(factory->the_hole_map(), "hole",
+ handle(Smi::FromInt(-1), isolate()),
+ Oddball::kTheHole));
+
+ set_uninitialized_value(*factory->NewOddball(
+ factory->uninitialized_map(), "uninitialized",
+ handle(Smi::FromInt(-1), isolate()), Oddball::kUninitialized));
+
+ set_arguments_marker(*factory->NewOddball(
+ factory->arguments_marker_map(), "arguments_marker",
+ handle(Smi::FromInt(-4), isolate()), Oddball::kArgumentMarker));
+
+ set_no_interceptor_result_sentinel(*factory->NewOddball(
+ factory->no_interceptor_result_sentinel_map(),
+ "no_interceptor_result_sentinel", handle(Smi::FromInt(-2), isolate()),
+ Oddball::kOther));
+
+ set_termination_exception(*factory->NewOddball(
+ factory->termination_exception_map(), "termination_exception",
+ handle(Smi::FromInt(-3), isolate()), Oddball::kOther));
+
+ set_exception(*factory->NewOddball(factory->exception_map(), "exception",
+ handle(Smi::FromInt(-5), isolate()),
+ Oddball::kException));
+
+ for (unsigned i = 0; i < arraysize(constant_string_table); i++) {
+ Handle<String> str =
+ factory->InternalizeUtf8String(constant_string_table[i].contents);
+ roots_[constant_string_table[i].index] = *str;
+ }
+
+ // Allocate the hidden string which is used to identify the hidden properties
+ // in JSObjects. The hash code has a special value so that it will not match
+ // the empty string when searching for the property. It cannot be part of the
+ // loop above because it needs to be allocated manually with the special
+ // hash code in place. The hash code for the hidden_string is zero to ensure
+ // that it will always be at the first entry in property descriptors.
+ hidden_string_ = *factory->NewOneByteInternalizedString(
+ OneByteVector("", 0), String::kEmptyStringHash);
+
+ // Create the code_stubs dictionary. The initial size is set to avoid
+ // expanding the dictionary during bootstrapping.
+ set_code_stubs(*UnseededNumberDictionary::New(isolate(), 128));
+
+ // Create the non_monomorphic_cache used in stub-cache.cc. The initial size
+ // is set to avoid expanding the dictionary during bootstrapping.
+ set_non_monomorphic_cache(*UnseededNumberDictionary::New(isolate(), 64));
+
+ set_polymorphic_code_cache(PolymorphicCodeCache::cast(
+ *factory->NewStruct(POLYMORPHIC_CODE_CACHE_TYPE)));
+
+ set_instanceof_cache_function(Smi::FromInt(0));
+ set_instanceof_cache_map(Smi::FromInt(0));
+ set_instanceof_cache_answer(Smi::FromInt(0));
+
+ CreateFixedStubs();
+
+ // Allocate the dictionary of intrinsic function names.
+ Handle<NameDictionary> intrinsic_names =
+ NameDictionary::New(isolate(), Runtime::kNumFunctions, TENURED);
+ Runtime::InitializeIntrinsicFunctionNames(isolate(), intrinsic_names);
+ set_intrinsic_function_names(*intrinsic_names);
+
+ set_number_string_cache(
+ *factory->NewFixedArray(kInitialNumberStringCacheSize * 2, TENURED));
+
+ // Allocate cache for single character one byte strings.
+ set_single_character_string_cache(
+ *factory->NewFixedArray(String::kMaxOneByteCharCode + 1, TENURED));
+
+ // Allocate cache for string split and regexp-multiple.
+ set_string_split_cache(*factory->NewFixedArray(
+ RegExpResultsCache::kRegExpResultsCacheSize, TENURED));
+ set_regexp_multiple_cache(*factory->NewFixedArray(
+ RegExpResultsCache::kRegExpResultsCacheSize, TENURED));
+
+ // Allocate cache for external strings pointing to native source code.
+ set_natives_source_cache(
+ *factory->NewFixedArray(Natives::GetBuiltinsCount()));
+
+ set_undefined_cell(*factory->NewCell(factory->undefined_value()));
+
+ // The symbol registry is initialized lazily.
+ set_symbol_registry(undefined_value());
+
+ // Allocate object to hold object observation state.
+ set_observation_state(*factory->NewJSObjectFromMap(
+ factory->NewMap(JS_OBJECT_TYPE, JSObject::kHeaderSize)));
+
+ // Microtask queue uses the empty fixed array as a sentinel for "empty".
+ // Number of queued microtasks stored in Isolate::pending_microtask_count().
+ set_microtask_queue(empty_fixed_array());
+
+ set_detailed_stack_trace_symbol(*factory->NewPrivateOwnSymbol());
+ set_elements_transition_symbol(*factory->NewPrivateOwnSymbol());
+ set_frozen_symbol(*factory->NewPrivateOwnSymbol());
+ set_megamorphic_symbol(*factory->NewPrivateOwnSymbol());
+ set_premonomorphic_symbol(*factory->NewPrivateOwnSymbol());
+ set_generic_symbol(*factory->NewPrivateOwnSymbol());
+ set_nonexistent_symbol(*factory->NewPrivateOwnSymbol());
+ set_normal_ic_symbol(*factory->NewPrivateOwnSymbol());
+ set_observed_symbol(*factory->NewPrivateOwnSymbol());
+ set_stack_trace_symbol(*factory->NewPrivateOwnSymbol());
+ set_uninitialized_symbol(*factory->NewPrivateOwnSymbol());
+ set_home_object_symbol(*factory->NewPrivateOwnSymbol());
+
+ Handle<SeededNumberDictionary> slow_element_dictionary =
+ SeededNumberDictionary::New(isolate(), 0, TENURED);
+ slow_element_dictionary->set_requires_slow_elements();
+ set_empty_slow_element_dictionary(*slow_element_dictionary);
+
+ set_materialized_objects(*factory->NewFixedArray(0, TENURED));
+
+ // Handling of script id generation is in Factory::NewScript.
+ set_last_script_id(Smi::FromInt(v8::UnboundScript::kNoScriptId));
+
+ set_allocation_sites_scratchpad(
+ *factory->NewFixedArray(kAllocationSiteScratchpadSize, TENURED));
+ InitializeAllocationSitesScratchpad();
+
+ // Initialize keyed lookup cache.
+ isolate_->keyed_lookup_cache()->Clear();
+
+ // Initialize context slot cache.
+ isolate_->context_slot_cache()->Clear();
+
+ // Initialize descriptor cache.
+ isolate_->descriptor_lookup_cache()->Clear();
+
+ // Initialize compilation cache.
+ isolate_->compilation_cache()->Clear();
+}
+
+
+bool Heap::RootCanBeWrittenAfterInitialization(Heap::RootListIndex root_index) {
+ RootListIndex writable_roots[] = {
+ kStoreBufferTopRootIndex,
+ kStackLimitRootIndex,
+ kNumberStringCacheRootIndex,
+ kInstanceofCacheFunctionRootIndex,
+ kInstanceofCacheMapRootIndex,
+ kInstanceofCacheAnswerRootIndex,
+ kCodeStubsRootIndex,
+ kNonMonomorphicCacheRootIndex,
+ kPolymorphicCodeCacheRootIndex,
+ kLastScriptIdRootIndex,
+ kEmptyScriptRootIndex,
+ kRealStackLimitRootIndex,
+ kArgumentsAdaptorDeoptPCOffsetRootIndex,
+ kConstructStubDeoptPCOffsetRootIndex,
+ kGetterStubDeoptPCOffsetRootIndex,
+ kSetterStubDeoptPCOffsetRootIndex,
+ kStringTableRootIndex,
+ };
+
+ for (unsigned int i = 0; i < arraysize(writable_roots); i++) {
+ if (root_index == writable_roots[i]) return true;
+ }
+ return false;
+}
+
+
+bool Heap::RootCanBeTreatedAsConstant(RootListIndex root_index) {
+ return !RootCanBeWrittenAfterInitialization(root_index) &&
+ !InNewSpace(roots_array_start()[root_index]);
+}
+
+
+Object* RegExpResultsCache::Lookup(Heap* heap, String* key_string,
+ Object* key_pattern, ResultsCacheType type) {
+ FixedArray* cache;
+ if (!key_string->IsInternalizedString()) return Smi::FromInt(0);
+ if (type == STRING_SPLIT_SUBSTRINGS) {
+ DCHECK(key_pattern->IsString());
+ if (!key_pattern->IsInternalizedString()) return Smi::FromInt(0);
+ cache = heap->string_split_cache();
+ } else {
+ DCHECK(type == REGEXP_MULTIPLE_INDICES);
+ DCHECK(key_pattern->IsFixedArray());
+ cache = heap->regexp_multiple_cache();
+ }
+
+ uint32_t hash = key_string->Hash();
+ uint32_t index = ((hash & (kRegExpResultsCacheSize - 1)) &
+ ~(kArrayEntriesPerCacheEntry - 1));
+ if (cache->get(index + kStringOffset) == key_string &&
+ cache->get(index + kPatternOffset) == key_pattern) {
+ return cache->get(index + kArrayOffset);
+ }
+ index =
+ ((index + kArrayEntriesPerCacheEntry) & (kRegExpResultsCacheSize - 1));
+ if (cache->get(index + kStringOffset) == key_string &&
+ cache->get(index + kPatternOffset) == key_pattern) {
+ return cache->get(index + kArrayOffset);
+ }
+ return Smi::FromInt(0);
+}
+
+
+void RegExpResultsCache::Enter(Isolate* isolate, Handle<String> key_string,
+ Handle<Object> key_pattern,
+ Handle<FixedArray> value_array,
+ ResultsCacheType type) {
+ Factory* factory = isolate->factory();
+ Handle<FixedArray> cache;
+ if (!key_string->IsInternalizedString()) return;
+ if (type == STRING_SPLIT_SUBSTRINGS) {
+ DCHECK(key_pattern->IsString());
+ if (!key_pattern->IsInternalizedString()) return;
+ cache = factory->string_split_cache();
+ } else {
+ DCHECK(type == REGEXP_MULTIPLE_INDICES);
+ DCHECK(key_pattern->IsFixedArray());
+ cache = factory->regexp_multiple_cache();
+ }
+
+ uint32_t hash = key_string->Hash();
+ uint32_t index = ((hash & (kRegExpResultsCacheSize - 1)) &
+ ~(kArrayEntriesPerCacheEntry - 1));
+ if (cache->get(index + kStringOffset) == Smi::FromInt(0)) {
+ cache->set(index + kStringOffset, *key_string);
+ cache->set(index + kPatternOffset, *key_pattern);
+ cache->set(index + kArrayOffset, *value_array);
+ } else {
+ uint32_t index2 =
+ ((index + kArrayEntriesPerCacheEntry) & (kRegExpResultsCacheSize - 1));
+ if (cache->get(index2 + kStringOffset) == Smi::FromInt(0)) {
+ cache->set(index2 + kStringOffset, *key_string);
+ cache->set(index2 + kPatternOffset, *key_pattern);
+ cache->set(index2 + kArrayOffset, *value_array);
+ } else {
+ cache->set(index2 + kStringOffset, Smi::FromInt(0));
+ cache->set(index2 + kPatternOffset, Smi::FromInt(0));
+ cache->set(index2 + kArrayOffset, Smi::FromInt(0));
+ cache->set(index + kStringOffset, *key_string);
+ cache->set(index + kPatternOffset, *key_pattern);
+ cache->set(index + kArrayOffset, *value_array);
+ }
+ }
+ // If the array is a reasonably short list of substrings, convert it into a
+ // list of internalized strings.
+ if (type == STRING_SPLIT_SUBSTRINGS && value_array->length() < 100) {
+ for (int i = 0; i < value_array->length(); i++) {
+ Handle<String> str(String::cast(value_array->get(i)), isolate);
+ Handle<String> internalized_str = factory->InternalizeString(str);
+ value_array->set(i, *internalized_str);
+ }
+ }
+ // Convert backing store to a copy-on-write array.
+ value_array->set_map_no_write_barrier(*factory->fixed_cow_array_map());
+}
+
+
+void RegExpResultsCache::Clear(FixedArray* cache) {
+ for (int i = 0; i < kRegExpResultsCacheSize; i++) {
+ cache->set(i, Smi::FromInt(0));
+ }
+}
+
+
+int Heap::FullSizeNumberStringCacheLength() {
+ // Compute the size of the number string cache based on the max newspace size.
+ // The number string cache has a minimum size based on twice the initial cache
+ // size to ensure that it is bigger after being made 'full size'.
+ int number_string_cache_size = max_semi_space_size_ / 512;
+ number_string_cache_size = Max(kInitialNumberStringCacheSize * 2,
+ Min(0x4000, number_string_cache_size));
+ // There is a string and a number per entry so the length is twice the number
+ // of entries.
+ return number_string_cache_size * 2;
+}
+
+
+void Heap::FlushNumberStringCache() {
+ // Flush the number to string cache.
+ int len = number_string_cache()->length();
+ for (int i = 0; i < len; i++) {
+ number_string_cache()->set_undefined(i);
+ }
+}
+
+
+void Heap::FlushAllocationSitesScratchpad() {
+ for (int i = 0; i < allocation_sites_scratchpad_length_; i++) {
+ allocation_sites_scratchpad()->set_undefined(i);
+ }
+ allocation_sites_scratchpad_length_ = 0;
+}
+
+
+void Heap::InitializeAllocationSitesScratchpad() {
+ DCHECK(allocation_sites_scratchpad()->length() ==
+ kAllocationSiteScratchpadSize);
+ for (int i = 0; i < kAllocationSiteScratchpadSize; i++) {
+ allocation_sites_scratchpad()->set_undefined(i);
+ }
+}
+
+
+void Heap::AddAllocationSiteToScratchpad(AllocationSite* site,
+ ScratchpadSlotMode mode) {
+ if (allocation_sites_scratchpad_length_ < kAllocationSiteScratchpadSize) {
+ // We cannot use the normal write-barrier because slots need to be
+ // recorded with non-incremental marking as well. We have to explicitly
+ // record the slot to take evacuation candidates into account.
+ allocation_sites_scratchpad()->set(allocation_sites_scratchpad_length_,
+ site, SKIP_WRITE_BARRIER);
+ Object** slot = allocation_sites_scratchpad()->RawFieldOfElementAt(
+ allocation_sites_scratchpad_length_);
+
+ if (mode == RECORD_SCRATCHPAD_SLOT) {
+ // We need to allow slots buffer overflow here since the evacuation
+ // candidates are not part of the global list of old space pages and
+ // releasing an evacuation candidate due to a slots buffer overflow
+ // results in lost pages.
+ mark_compact_collector()->RecordSlot(slot, slot, *slot,
+ SlotsBuffer::IGNORE_OVERFLOW);
+ }
+ allocation_sites_scratchpad_length_++;
+ }
+}
+
+
+Map* Heap::MapForExternalArrayType(ExternalArrayType array_type) {
+ return Map::cast(roots_[RootIndexForExternalArrayType(array_type)]);
+}
+
+
+Heap::RootListIndex Heap::RootIndexForExternalArrayType(
+ ExternalArrayType array_type) {
+ switch (array_type) {
+#define ARRAY_TYPE_TO_ROOT_INDEX(Type, type, TYPE, ctype, size) \
+ case kExternal##Type##Array: \
+ return kExternal##Type##ArrayMapRootIndex;
+
+ TYPED_ARRAYS(ARRAY_TYPE_TO_ROOT_INDEX)
+#undef ARRAY_TYPE_TO_ROOT_INDEX
+
+ default:
+ UNREACHABLE();
+ return kUndefinedValueRootIndex;
+ }
+}
+
+
+Map* Heap::MapForFixedTypedArray(ExternalArrayType array_type) {
+ return Map::cast(roots_[RootIndexForFixedTypedArray(array_type)]);
+}
+
+
+Heap::RootListIndex Heap::RootIndexForFixedTypedArray(
+ ExternalArrayType array_type) {
+ switch (array_type) {
+#define ARRAY_TYPE_TO_ROOT_INDEX(Type, type, TYPE, ctype, size) \
+ case kExternal##Type##Array: \
+ return kFixed##Type##ArrayMapRootIndex;
+
+ TYPED_ARRAYS(ARRAY_TYPE_TO_ROOT_INDEX)
+#undef ARRAY_TYPE_TO_ROOT_INDEX
+
+ default:
+ UNREACHABLE();
+ return kUndefinedValueRootIndex;
+ }
+}
+
+
+Heap::RootListIndex Heap::RootIndexForEmptyExternalArray(
+ ElementsKind elementsKind) {
+ switch (elementsKind) {
+#define ELEMENT_KIND_TO_ROOT_INDEX(Type, type, TYPE, ctype, size) \
+ case EXTERNAL_##TYPE##_ELEMENTS: \
+ return kEmptyExternal##Type##ArrayRootIndex;
+
+ TYPED_ARRAYS(ELEMENT_KIND_TO_ROOT_INDEX)
+#undef ELEMENT_KIND_TO_ROOT_INDEX
+
+ default:
+ UNREACHABLE();
+ return kUndefinedValueRootIndex;
+ }
+}
+
+
+Heap::RootListIndex Heap::RootIndexForEmptyFixedTypedArray(
+ ElementsKind elementsKind) {
+ switch (elementsKind) {
+#define ELEMENT_KIND_TO_ROOT_INDEX(Type, type, TYPE, ctype, size) \
+ case TYPE##_ELEMENTS: \
+ return kEmptyFixed##Type##ArrayRootIndex;
+
+ TYPED_ARRAYS(ELEMENT_KIND_TO_ROOT_INDEX)
+#undef ELEMENT_KIND_TO_ROOT_INDEX
+ default:
+ UNREACHABLE();
+ return kUndefinedValueRootIndex;
+ }
+}
+
+
+ExternalArray* Heap::EmptyExternalArrayForMap(Map* map) {
+ return ExternalArray::cast(
+ roots_[RootIndexForEmptyExternalArray(map->elements_kind())]);
+}
+
+
+FixedTypedArrayBase* Heap::EmptyFixedTypedArrayForMap(Map* map) {
+ return FixedTypedArrayBase::cast(
+ roots_[RootIndexForEmptyFixedTypedArray(map->elements_kind())]);
+}
+
+
+AllocationResult Heap::AllocateForeign(Address address,
+ PretenureFlag pretenure) {
+ // Statically ensure that it is safe to allocate foreigns in paged spaces.
+ STATIC_ASSERT(Foreign::kSize <= Page::kMaxRegularHeapObjectSize);
+ AllocationSpace space = (pretenure == TENURED) ? OLD_DATA_SPACE : NEW_SPACE;
+ Foreign* result;
+ AllocationResult allocation = Allocate(foreign_map(), space);
+ if (!allocation.To(&result)) return allocation;
+ result->set_foreign_address(address);
+ return result;
+}
+
+
+AllocationResult Heap::AllocateByteArray(int length, PretenureFlag pretenure) {
+ if (length < 0 || length > ByteArray::kMaxLength) {
+ v8::internal::Heap::FatalProcessOutOfMemory("invalid array length", true);
+ }
+ int size = ByteArray::SizeFor(length);
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, pretenure);
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ result->set_map_no_write_barrier(byte_array_map());
+ ByteArray::cast(result)->set_length(length);
+ return result;
+}
+
+
+void Heap::CreateFillerObjectAt(Address addr, int size) {
+ if (size == 0) return;
+ HeapObject* filler = HeapObject::FromAddress(addr);
+ if (size == kPointerSize) {
+ filler->set_map_no_write_barrier(one_pointer_filler_map());
+ } else if (size == 2 * kPointerSize) {
+ filler->set_map_no_write_barrier(two_pointer_filler_map());
+ } else {
+ filler->set_map_no_write_barrier(free_space_map());
+ FreeSpace::cast(filler)->set_size(size);
+ }
+}
+
+
+bool Heap::CanMoveObjectStart(HeapObject* object) {
+ Address address = object->address();
+ bool is_in_old_pointer_space = InOldPointerSpace(address);
+ bool is_in_old_data_space = InOldDataSpace(address);
+
+ if (lo_space()->Contains(object)) return false;
+
+ Page* page = Page::FromAddress(address);
+ // We can move the object start if:
+ // (1) the object is not in old pointer or old data space,
+ // (2) the page of the object was already swept,
+ // (3) the page was already concurrently swept. This case is an optimization
+ // for concurrent sweeping. The WasSwept predicate for concurrently swept
+ // pages is set after sweeping all pages.
+ return (!is_in_old_pointer_space && !is_in_old_data_space) ||
+ page->WasSwept() || page->SweepingCompleted();
+}
+
+
+void Heap::AdjustLiveBytes(Address address, int by, InvocationMode mode) {
+ if (incremental_marking()->IsMarking() &&
+ Marking::IsBlack(Marking::MarkBitFrom(address))) {
+ if (mode == FROM_GC) {
+ MemoryChunk::IncrementLiveBytesFromGC(address, by);
+ } else {
+ MemoryChunk::IncrementLiveBytesFromMutator(address, by);
+ }
+ }
+}
+
+
+FixedArrayBase* Heap::LeftTrimFixedArray(FixedArrayBase* object,
+ int elements_to_trim) {
+ const int element_size = object->IsFixedArray() ? kPointerSize : kDoubleSize;
+ const int bytes_to_trim = elements_to_trim * element_size;
+ Map* map = object->map();
+
+ // For now this trick is only applied to objects in new and paged space.
+ // In large object space the object's start must coincide with chunk
+ // and thus the trick is just not applicable.
+ DCHECK(!lo_space()->Contains(object));
+ DCHECK(object->map() != fixed_cow_array_map());
+
+ STATIC_ASSERT(FixedArrayBase::kMapOffset == 0);
+ STATIC_ASSERT(FixedArrayBase::kLengthOffset == kPointerSize);
+ STATIC_ASSERT(FixedArrayBase::kHeaderSize == 2 * kPointerSize);
+
+ const int len = object->length();
+ DCHECK(elements_to_trim <= len);
+
+ // Calculate location of new array start.
+ Address new_start = object->address() + bytes_to_trim;
+
+ // Technically in new space this write might be omitted (except for
+ // debug mode which iterates through the heap), but to play safer
+ // we still do it.
+ CreateFillerObjectAt(object->address(), bytes_to_trim);
+
+ // Initialize header of the trimmed array. Since left trimming is only
+ // performed on pages which are not concurrently swept creating a filler
+ // object does not require synchronization.
+ DCHECK(CanMoveObjectStart(object));
+ Object** former_start = HeapObject::RawField(object, 0);
+ int new_start_index = elements_to_trim * (element_size / kPointerSize);
+ former_start[new_start_index] = map;
+ former_start[new_start_index + 1] = Smi::FromInt(len - elements_to_trim);
+ FixedArrayBase* new_object =
+ FixedArrayBase::cast(HeapObject::FromAddress(new_start));
+
+ // Maintain consistency of live bytes during incremental marking
+ marking()->TransferMark(object->address(), new_start);
+ AdjustLiveBytes(new_start, -bytes_to_trim, Heap::FROM_MUTATOR);
+
+ // Notify the heap profiler of change in object layout.
+ OnMoveEvent(new_object, object, new_object->Size());
+ return new_object;
+}
+
+
+// Force instantiation of templatized method.
+template
+void Heap::RightTrimFixedArray<Heap::FROM_GC>(FixedArrayBase*, int);
+template
+void Heap::RightTrimFixedArray<Heap::FROM_MUTATOR>(FixedArrayBase*, int);
+
+
+template<Heap::InvocationMode mode>
+void Heap::RightTrimFixedArray(FixedArrayBase* object, int elements_to_trim) {
+ const int element_size = object->IsFixedArray() ? kPointerSize : kDoubleSize;
+ const int bytes_to_trim = elements_to_trim * element_size;
+
+ // For now this trick is only applied to objects in new and paged space.
+ DCHECK(object->map() != fixed_cow_array_map());
+
+ const int len = object->length();
+ DCHECK(elements_to_trim < len);
+
+ // Calculate location of new array end.
+ Address new_end = object->address() + object->Size() - bytes_to_trim;
+
+ // Technically in new space this write might be omitted (except for
+ // debug mode which iterates through the heap), but to play safer
+ // we still do it.
+ // We do not create a filler for objects in large object space.
+ // TODO(hpayer): We should shrink the large object page if the size
+ // of the object changed significantly.
+ if (!lo_space()->Contains(object)) {
+ CreateFillerObjectAt(new_end, bytes_to_trim);
+ }
+
+ // Initialize header of the trimmed array. We are storing the new length
+ // using release store after creating a filler for the left-over space to
+ // avoid races with the sweeper thread.
+ object->synchronized_set_length(len - elements_to_trim);
+
+ // Maintain consistency of live bytes during incremental marking
+ AdjustLiveBytes(object->address(), -bytes_to_trim, mode);
+
+ // Notify the heap profiler of change in object layout. The array may not be
+ // moved during GC, and size has to be adjusted nevertheless.
+ HeapProfiler* profiler = isolate()->heap_profiler();
+ if (profiler->is_tracking_allocations()) {
+ profiler->UpdateObjectSizeEvent(object->address(), object->Size());
+ }
+}
+
+
+AllocationResult Heap::AllocateExternalArray(int length,
+ ExternalArrayType array_type,
+ void* external_pointer,
+ PretenureFlag pretenure) {
+ int size = ExternalArray::kAlignedSize;
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, pretenure);
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ result->set_map_no_write_barrier(MapForExternalArrayType(array_type));
+ ExternalArray::cast(result)->set_length(length);
+ ExternalArray::cast(result)->set_external_pointer(external_pointer);
+ return result;
+}
+
+static void ForFixedTypedArray(ExternalArrayType array_type, int* element_size,
+ ElementsKind* element_kind) {
+ switch (array_type) {
+#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
+ case kExternal##Type##Array: \
+ *element_size = size; \
+ *element_kind = TYPE##_ELEMENTS; \
+ return;
+
+ TYPED_ARRAYS(TYPED_ARRAY_CASE)
+#undef TYPED_ARRAY_CASE
+
+ default:
+ *element_size = 0; // Bogus
+ *element_kind = UINT8_ELEMENTS; // Bogus
+ UNREACHABLE();
+ }
+}
+
+
+AllocationResult Heap::AllocateFixedTypedArray(int length,
+ ExternalArrayType array_type,
+ PretenureFlag pretenure) {
+ int element_size;
+ ElementsKind elements_kind;
+ ForFixedTypedArray(array_type, &element_size, &elements_kind);
+ int size = OBJECT_POINTER_ALIGN(length * element_size +
+ FixedTypedArrayBase::kDataOffset);
+#ifndef V8_HOST_ARCH_64_BIT
+ if (array_type == kExternalFloat64Array) {
+ size += kPointerSize;
+ }
+#endif
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, pretenure);
+
+ HeapObject* object;
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&object)) return allocation;
+
+ if (array_type == kExternalFloat64Array) {
+ object = EnsureDoubleAligned(this, object, size);
+ }
+
+ object->set_map(MapForFixedTypedArray(array_type));
+ FixedTypedArrayBase* elements = FixedTypedArrayBase::cast(object);
+ elements->set_length(length);
+ memset(elements->DataPtr(), 0, elements->DataSize());
+ return elements;
+}
+
+
+AllocationResult Heap::AllocateCode(int object_size, bool immovable) {
+ DCHECK(IsAligned(static_cast<intptr_t>(object_size), kCodeAlignment));
+ AllocationResult allocation =
+ AllocateRaw(object_size, CODE_SPACE, CODE_SPACE);
+
+ HeapObject* result;
+ if (!allocation.To(&result)) return allocation;
+
+ if (immovable) {
+ Address address = result->address();
+ // Code objects which should stay at a fixed address are allocated either
+ // in the first page of code space (objects on the first page of each space
+ // are never moved) or in large object space.
+ if (!code_space_->FirstPage()->Contains(address) &&
+ MemoryChunk::FromAddress(address)->owner()->identity() != LO_SPACE) {
+ // Discard the first code allocation, which was on a page where it could
+ // be moved.
+ CreateFillerObjectAt(result->address(), object_size);
+ allocation = lo_space_->AllocateRaw(object_size, EXECUTABLE);
+ if (!allocation.To(&result)) return allocation;
+ OnAllocationEvent(result, object_size);
+ }
+ }
+
+ result->set_map_no_write_barrier(code_map());
+ Code* code = Code::cast(result);
+ DCHECK(isolate_->code_range() == NULL || !isolate_->code_range()->valid() ||
+ isolate_->code_range()->contains(code->address()));
+ code->set_gc_metadata(Smi::FromInt(0));
+ code->set_ic_age(global_ic_age_);
+ return code;
+}
+
+
+AllocationResult Heap::CopyCode(Code* code) {
+ AllocationResult allocation;
+ HeapObject* new_constant_pool;
+ if (FLAG_enable_ool_constant_pool &&
+ code->constant_pool() != empty_constant_pool_array()) {
+ // Copy the constant pool, since edits to the copied code may modify
+ // the constant pool.
+ allocation = CopyConstantPoolArray(code->constant_pool());
+ if (!allocation.To(&new_constant_pool)) return allocation;
+ } else {
+ new_constant_pool = empty_constant_pool_array();
+ }
+
+ HeapObject* result;
+ // Allocate an object the same size as the code object.
+ int obj_size = code->Size();
+ allocation = AllocateRaw(obj_size, CODE_SPACE, CODE_SPACE);
+ if (!allocation.To(&result)) return allocation;
+
+ // Copy code object.
+ Address old_addr = code->address();
+ Address new_addr = result->address();
+ CopyBlock(new_addr, old_addr, obj_size);
+ Code* new_code = Code::cast(result);
+
+ // Update the constant pool.
+ new_code->set_constant_pool(new_constant_pool);
+
+ // Relocate the copy.
+ DCHECK(isolate_->code_range() == NULL || !isolate_->code_range()->valid() ||
+ isolate_->code_range()->contains(code->address()));
+ new_code->Relocate(new_addr - old_addr);
+ return new_code;
+}
+
+
+AllocationResult Heap::CopyCode(Code* code, Vector<byte> reloc_info) {
+ // Allocate ByteArray and ConstantPoolArray before the Code object, so that we
+ // do not risk leaving uninitialized Code object (and breaking the heap).
+ ByteArray* reloc_info_array;
+ {
+ AllocationResult allocation =
+ AllocateByteArray(reloc_info.length(), TENURED);
+ if (!allocation.To(&reloc_info_array)) return allocation;
+ }
+ HeapObject* new_constant_pool;
+ if (FLAG_enable_ool_constant_pool &&
+ code->constant_pool() != empty_constant_pool_array()) {
+ // Copy the constant pool, since edits to the copied code may modify
+ // the constant pool.
+ AllocationResult allocation = CopyConstantPoolArray(code->constant_pool());
+ if (!allocation.To(&new_constant_pool)) return allocation;
+ } else {
+ new_constant_pool = empty_constant_pool_array();
+ }
+
+ int new_body_size = RoundUp(code->instruction_size(), kObjectAlignment);
+
+ int new_obj_size = Code::SizeFor(new_body_size);
+
+ Address old_addr = code->address();
+
+ size_t relocation_offset =
+ static_cast<size_t>(code->instruction_end() - old_addr);
+
+ HeapObject* result;
+ AllocationResult allocation =
+ AllocateRaw(new_obj_size, CODE_SPACE, CODE_SPACE);
+ if (!allocation.To(&result)) return allocation;
+
+ // Copy code object.
+ Address new_addr = result->address();
+
+ // Copy header and instructions.
+ CopyBytes(new_addr, old_addr, relocation_offset);
+
+ Code* new_code = Code::cast(result);
+ new_code->set_relocation_info(reloc_info_array);
+
+ // Update constant pool.
+ new_code->set_constant_pool(new_constant_pool);
+
+ // Copy patched rinfo.
+ CopyBytes(new_code->relocation_start(), reloc_info.start(),
+ static_cast<size_t>(reloc_info.length()));
+
+ // Relocate the copy.
+ DCHECK(isolate_->code_range() == NULL || !isolate_->code_range()->valid() ||
+ isolate_->code_range()->contains(code->address()));
+ new_code->Relocate(new_addr - old_addr);
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) code->ObjectVerify();
+#endif
+ return new_code;
+}
+
+
+void Heap::InitializeAllocationMemento(AllocationMemento* memento,
+ AllocationSite* allocation_site) {
+ memento->set_map_no_write_barrier(allocation_memento_map());
+ DCHECK(allocation_site->map() == allocation_site_map());
+ memento->set_allocation_site(allocation_site, SKIP_WRITE_BARRIER);
+ if (FLAG_allocation_site_pretenuring) {
+ allocation_site->IncrementMementoCreateCount();
+ }
+}
+
+
+AllocationResult Heap::Allocate(Map* map, AllocationSpace space,
+ AllocationSite* allocation_site) {
+ DCHECK(gc_state_ == NOT_IN_GC);
+ DCHECK(map->instance_type() != MAP_TYPE);
+ // If allocation failures are disallowed, we may allocate in a different
+ // space when new space is full and the object is not a large object.
+ AllocationSpace retry_space =
+ (space != NEW_SPACE) ? space : TargetSpaceId(map->instance_type());
+ int size = map->instance_size();
+ if (allocation_site != NULL) {
+ size += AllocationMemento::kSize;
+ }
+ HeapObject* result;
+ AllocationResult allocation = AllocateRaw(size, space, retry_space);
+ if (!allocation.To(&result)) return allocation;
+ // No need for write barrier since object is white and map is in old space.
+ result->set_map_no_write_barrier(map);
+ if (allocation_site != NULL) {
+ AllocationMemento* alloc_memento = reinterpret_cast<AllocationMemento*>(
+ reinterpret_cast<Address>(result) + map->instance_size());
+ InitializeAllocationMemento(alloc_memento, allocation_site);
+ }
+ return result;
+}
+
+
+void Heap::InitializeJSObjectFromMap(JSObject* obj, FixedArray* properties,
+ Map* map) {
+ obj->set_properties(properties);
+ obj->initialize_elements();
+ // TODO(1240798): Initialize the object's body using valid initial values
+ // according to the object's initial map. For example, if the map's
+ // instance type is JS_ARRAY_TYPE, the length field should be initialized
+ // to a number (e.g. Smi::FromInt(0)) and the elements initialized to a
+ // fixed array (e.g. Heap::empty_fixed_array()). Currently, the object
+ // verification code has to cope with (temporarily) invalid objects. See
+ // for example, JSArray::JSArrayVerify).
+ Object* filler;
+ // We cannot always fill with one_pointer_filler_map because objects
+ // created from API functions expect their internal fields to be initialized
+ // with undefined_value.
+ // Pre-allocated fields need to be initialized with undefined_value as well
+ // so that object accesses before the constructor completes (e.g. in the
+ // debugger) will not cause a crash.
+ if (map->constructor()->IsJSFunction() &&
+ JSFunction::cast(map->constructor())
+ ->IsInobjectSlackTrackingInProgress()) {
+ // We might want to shrink the object later.
+ DCHECK(obj->GetInternalFieldCount() == 0);
+ filler = Heap::one_pointer_filler_map();
+ } else {
+ filler = Heap::undefined_value();
+ }
+ obj->InitializeBody(map, Heap::undefined_value(), filler);
+}
+
+
+AllocationResult Heap::AllocateJSObjectFromMap(
+ Map* map, PretenureFlag pretenure, bool allocate_properties,
+ AllocationSite* allocation_site) {
+ // JSFunctions should be allocated using AllocateFunction to be
+ // properly initialized.
+ DCHECK(map->instance_type() != JS_FUNCTION_TYPE);
+
+ // Both types of global objects should be allocated using
+ // AllocateGlobalObject to be properly initialized.
+ DCHECK(map->instance_type() != JS_GLOBAL_OBJECT_TYPE);
+ DCHECK(map->instance_type() != JS_BUILTINS_OBJECT_TYPE);
+
+ // Allocate the backing storage for the properties.
+ FixedArray* properties;
+ if (allocate_properties) {
+ int prop_size = map->InitialPropertiesLength();
+ DCHECK(prop_size >= 0);
+ {
+ AllocationResult allocation = AllocateFixedArray(prop_size, pretenure);
+ if (!allocation.To(&properties)) return allocation;
+ }
+ } else {
+ properties = empty_fixed_array();
+ }
+
+ // Allocate the JSObject.
+ int size = map->instance_size();
+ AllocationSpace space = SelectSpace(size, OLD_POINTER_SPACE, pretenure);
+ JSObject* js_obj;
+ AllocationResult allocation = Allocate(map, space, allocation_site);
+ if (!allocation.To(&js_obj)) return allocation;
+
+ // Initialize the JSObject.
+ InitializeJSObjectFromMap(js_obj, properties, map);
+ DCHECK(js_obj->HasFastElements() || js_obj->HasExternalArrayElements() ||
+ js_obj->HasFixedTypedArrayElements());
+ return js_obj;
+}
+
+
+AllocationResult Heap::AllocateJSObject(JSFunction* constructor,
+ PretenureFlag pretenure,
+ AllocationSite* allocation_site) {
+ DCHECK(constructor->has_initial_map());
+
+ // Allocate the object based on the constructors initial map.
+ AllocationResult allocation = AllocateJSObjectFromMap(
+ constructor->initial_map(), pretenure, true, allocation_site);
+#ifdef DEBUG
+ // Make sure result is NOT a global object if valid.
+ HeapObject* obj;
+ DCHECK(!allocation.To(&obj) || !obj->IsGlobalObject());
+#endif
+ return allocation;
+}
+
+
+AllocationResult Heap::CopyJSObject(JSObject* source, AllocationSite* site) {
+ // Never used to copy functions. If functions need to be copied we
+ // have to be careful to clear the literals array.
+ SLOW_DCHECK(!source->IsJSFunction());
+
+ // Make the clone.
+ Map* map = source->map();
+ int object_size = map->instance_size();
+ HeapObject* clone;
+
+ DCHECK(site == NULL || AllocationSite::CanTrack(map->instance_type()));
+
+ WriteBarrierMode wb_mode = UPDATE_WRITE_BARRIER;
+
+ // If we're forced to always allocate, we use the general allocation
+ // functions which may leave us with an object in old space.
+ if (always_allocate()) {
+ {
+ AllocationResult allocation =
+ AllocateRaw(object_size, NEW_SPACE, OLD_POINTER_SPACE);
+ if (!allocation.To(&clone)) return allocation;
+ }
+ Address clone_address = clone->address();
+ CopyBlock(clone_address, source->address(), object_size);
+ // Update write barrier for all fields that lie beyond the header.
+ RecordWrites(clone_address, JSObject::kHeaderSize,
+ (object_size - JSObject::kHeaderSize) / kPointerSize);
+ } else {
+ wb_mode = SKIP_WRITE_BARRIER;
+
+ {
+ int adjusted_object_size =
+ site != NULL ? object_size + AllocationMemento::kSize : object_size;
+ AllocationResult allocation =
+ AllocateRaw(adjusted_object_size, NEW_SPACE, NEW_SPACE);
+ if (!allocation.To(&clone)) return allocation;
+ }
+ SLOW_DCHECK(InNewSpace(clone));
+ // Since we know the clone is allocated in new space, we can copy
+ // the contents without worrying about updating the write barrier.
+ CopyBlock(clone->address(), source->address(), object_size);
+
+ if (site != NULL) {
+ AllocationMemento* alloc_memento = reinterpret_cast<AllocationMemento*>(
+ reinterpret_cast<Address>(clone) + object_size);
+ InitializeAllocationMemento(alloc_memento, site);
+ }
+ }
+
+ SLOW_DCHECK(JSObject::cast(clone)->GetElementsKind() ==
+ source->GetElementsKind());
+ FixedArrayBase* elements = FixedArrayBase::cast(source->elements());
+ FixedArray* properties = FixedArray::cast(source->properties());
+ // Update elements if necessary.
+ if (elements->length() > 0) {
+ FixedArrayBase* elem;
+ {
+ AllocationResult allocation;
+ if (elements->map() == fixed_cow_array_map()) {
+ allocation = FixedArray::cast(elements);
+ } else if (source->HasFastDoubleElements()) {
+ allocation = CopyFixedDoubleArray(FixedDoubleArray::cast(elements));
+ } else {
+ allocation = CopyFixedArray(FixedArray::cast(elements));
+ }
+ if (!allocation.To(&elem)) return allocation;
+ }
+ JSObject::cast(clone)->set_elements(elem, wb_mode);
+ }
+ // Update properties if necessary.
+ if (properties->length() > 0) {
+ FixedArray* prop;
+ {
+ AllocationResult allocation = CopyFixedArray(properties);
+ if (!allocation.To(&prop)) return allocation;
+ }
+ JSObject::cast(clone)->set_properties(prop, wb_mode);
+ }
+ // Return the new clone.
+ return clone;
+}
+
+
+static inline void WriteOneByteData(Vector<const char> vector, uint8_t* chars,
+ int len) {
+ // Only works for one byte strings.
+ DCHECK(vector.length() == len);
+ MemCopy(chars, vector.start(), len);
+}
+
+static inline void WriteTwoByteData(Vector<const char> vector, uint16_t* chars,
+ int len) {
+ const uint8_t* stream = reinterpret_cast<const uint8_t*>(vector.start());
+ unsigned stream_length = vector.length();
+ while (stream_length != 0) {
+ unsigned consumed = 0;
+ uint32_t c = unibrow::Utf8::ValueOf(stream, stream_length, &consumed);
+ DCHECK(c != unibrow::Utf8::kBadChar);
+ DCHECK(consumed <= stream_length);
+ stream_length -= consumed;
+ stream += consumed;
+ if (c > unibrow::Utf16::kMaxNonSurrogateCharCode) {
+ len -= 2;
+ if (len < 0) break;
+ *chars++ = unibrow::Utf16::LeadSurrogate(c);
+ *chars++ = unibrow::Utf16::TrailSurrogate(c);
+ } else {
+ len -= 1;
+ if (len < 0) break;
+ *chars++ = c;
+ }
+ }
+ DCHECK(stream_length == 0);
+ DCHECK(len == 0);
+}
+
+
+static inline void WriteOneByteData(String* s, uint8_t* chars, int len) {
+ DCHECK(s->length() == len);
+ String::WriteToFlat(s, chars, 0, len);
+}
+
+
+static inline void WriteTwoByteData(String* s, uint16_t* chars, int len) {
+ DCHECK(s->length() == len);
+ String::WriteToFlat(s, chars, 0, len);
+}
+
+
+template <bool is_one_byte, typename T>
+AllocationResult Heap::AllocateInternalizedStringImpl(T t, int chars,
+ uint32_t hash_field) {
+ DCHECK(chars >= 0);
+ // Compute map and object size.
+ int size;
+ Map* map;
+
+ DCHECK_LE(0, chars);
+ DCHECK_GE(String::kMaxLength, chars);
+ if (is_one_byte) {
+ map = one_byte_internalized_string_map();
+ size = SeqOneByteString::SizeFor(chars);
+ } else {
+ map = internalized_string_map();
+ size = SeqTwoByteString::SizeFor(chars);
+ }
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, TENURED);
+
+ // Allocate string.
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ result->set_map_no_write_barrier(map);
+ // Set length and hash fields of the allocated string.
+ String* answer = String::cast(result);
+ answer->set_length(chars);
+ answer->set_hash_field(hash_field);
+
+ DCHECK_EQ(size, answer->Size());
+
+ if (is_one_byte) {
+ WriteOneByteData(t, SeqOneByteString::cast(answer)->GetChars(), chars);
+ } else {
+ WriteTwoByteData(t, SeqTwoByteString::cast(answer)->GetChars(), chars);
+ }
+ return answer;
+}
+
+
+// Need explicit instantiations.
+template AllocationResult Heap::AllocateInternalizedStringImpl<true>(String*,
+ int,
+ uint32_t);
+template AllocationResult Heap::AllocateInternalizedStringImpl<false>(String*,
+ int,
+ uint32_t);
+template AllocationResult Heap::AllocateInternalizedStringImpl<false>(
+ Vector<const char>, int, uint32_t);
+
+
+AllocationResult Heap::AllocateRawOneByteString(int length,
+ PretenureFlag pretenure) {
+ DCHECK_LE(0, length);
+ DCHECK_GE(String::kMaxLength, length);
+ int size = SeqOneByteString::SizeFor(length);
+ DCHECK(size <= SeqOneByteString::kMaxSize);
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, pretenure);
+
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ // Partially initialize the object.
+ result->set_map_no_write_barrier(one_byte_string_map());
+ String::cast(result)->set_length(length);
+ String::cast(result)->set_hash_field(String::kEmptyHashField);
+ DCHECK_EQ(size, HeapObject::cast(result)->Size());
+
+ return result;
+}
+
+
+AllocationResult Heap::AllocateRawTwoByteString(int length,
+ PretenureFlag pretenure) {
+ DCHECK_LE(0, length);
+ DCHECK_GE(String::kMaxLength, length);
+ int size = SeqTwoByteString::SizeFor(length);
+ DCHECK(size <= SeqTwoByteString::kMaxSize);
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, pretenure);
+
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ // Partially initialize the object.
+ result->set_map_no_write_barrier(string_map());
+ String::cast(result)->set_length(length);
+ String::cast(result)->set_hash_field(String::kEmptyHashField);
+ DCHECK_EQ(size, HeapObject::cast(result)->Size());
+ return result;
+}
+
+
+AllocationResult Heap::AllocateEmptyFixedArray() {
+ int size = FixedArray::SizeFor(0);
+ HeapObject* result;
+ {
+ AllocationResult allocation =
+ AllocateRaw(size, OLD_DATA_SPACE, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+ // Initialize the object.
+ result->set_map_no_write_barrier(fixed_array_map());
+ FixedArray::cast(result)->set_length(0);
+ return result;
+}
+
+
+AllocationResult Heap::AllocateEmptyExternalArray(
+ ExternalArrayType array_type) {
+ return AllocateExternalArray(0, array_type, NULL, TENURED);
+}
+
+
+AllocationResult Heap::CopyAndTenureFixedCOWArray(FixedArray* src) {
+ if (!InNewSpace(src)) {
+ return src;
+ }
+
+ int len = src->length();
+ HeapObject* obj;
+ {
+ AllocationResult allocation = AllocateRawFixedArray(len, TENURED);
+ if (!allocation.To(&obj)) return allocation;
+ }
+ obj->set_map_no_write_barrier(fixed_array_map());
+ FixedArray* result = FixedArray::cast(obj);
+ result->set_length(len);
+
+ // Copy the content
+ DisallowHeapAllocation no_gc;
+ WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
+ for (int i = 0; i < len; i++) result->set(i, src->get(i), mode);
+
+ // TODO(mvstanton): The map is set twice because of protection against calling
+ // set() on a COW FixedArray. Issue v8:3221 created to track this, and
+ // we might then be able to remove this whole method.
+ HeapObject::cast(obj)->set_map_no_write_barrier(fixed_cow_array_map());
+ return result;
+}
+
+
+AllocationResult Heap::AllocateEmptyFixedTypedArray(
+ ExternalArrayType array_type) {
+ return AllocateFixedTypedArray(0, array_type, TENURED);
+}
+
+
+AllocationResult Heap::CopyFixedArrayWithMap(FixedArray* src, Map* map) {
+ int len = src->length();
+ HeapObject* obj;
+ {
+ AllocationResult allocation = AllocateRawFixedArray(len, NOT_TENURED);
+ if (!allocation.To(&obj)) return allocation;
+ }
+ if (InNewSpace(obj)) {
+ obj->set_map_no_write_barrier(map);
+ CopyBlock(obj->address() + kPointerSize, src->address() + kPointerSize,
+ FixedArray::SizeFor(len) - kPointerSize);
+ return obj;
+ }
+ obj->set_map_no_write_barrier(map);
+ FixedArray* result = FixedArray::cast(obj);
+ result->set_length(len);
+
+ // Copy the content
+ DisallowHeapAllocation no_gc;
+ WriteBarrierMode mode = result->GetWriteBarrierMode(no_gc);
+ for (int i = 0; i < len; i++) result->set(i, src->get(i), mode);
+ return result;
+}
+
+
+AllocationResult Heap::CopyFixedDoubleArrayWithMap(FixedDoubleArray* src,
+ Map* map) {
+ int len = src->length();
+ HeapObject* obj;
+ {
+ AllocationResult allocation = AllocateRawFixedDoubleArray(len, NOT_TENURED);
+ if (!allocation.To(&obj)) return allocation;
+ }
+ obj->set_map_no_write_barrier(map);
+ CopyBlock(obj->address() + FixedDoubleArray::kLengthOffset,
+ src->address() + FixedDoubleArray::kLengthOffset,
+ FixedDoubleArray::SizeFor(len) - FixedDoubleArray::kLengthOffset);
+ return obj;
+}
+
+
+AllocationResult Heap::CopyConstantPoolArrayWithMap(ConstantPoolArray* src,
+ Map* map) {
+ HeapObject* obj;
+ if (src->is_extended_layout()) {
+ ConstantPoolArray::NumberOfEntries small(src,
+ ConstantPoolArray::SMALL_SECTION);
+ ConstantPoolArray::NumberOfEntries extended(
+ src, ConstantPoolArray::EXTENDED_SECTION);
+ AllocationResult allocation =
+ AllocateExtendedConstantPoolArray(small, extended);
+ if (!allocation.To(&obj)) return allocation;
+ } else {
+ ConstantPoolArray::NumberOfEntries small(src,
+ ConstantPoolArray::SMALL_SECTION);
+ AllocationResult allocation = AllocateConstantPoolArray(small);
+ if (!allocation.To(&obj)) return allocation;
+ }
+ obj->set_map_no_write_barrier(map);
+ CopyBlock(obj->address() + ConstantPoolArray::kFirstEntryOffset,
+ src->address() + ConstantPoolArray::kFirstEntryOffset,
+ src->size() - ConstantPoolArray::kFirstEntryOffset);
+ return obj;
+}
+
+
+AllocationResult Heap::AllocateRawFixedArray(int length,
+ PretenureFlag pretenure) {
+ if (length < 0 || length > FixedArray::kMaxLength) {
+ v8::internal::Heap::FatalProcessOutOfMemory("invalid array length", true);
+ }
+ int size = FixedArray::SizeFor(length);
+ AllocationSpace space = SelectSpace(size, OLD_POINTER_SPACE, pretenure);
+
+ return AllocateRaw(size, space, OLD_POINTER_SPACE);
+}
+
+
+AllocationResult Heap::AllocateFixedArrayWithFiller(int length,
+ PretenureFlag pretenure,
+ Object* filler) {
+ DCHECK(length >= 0);
+ DCHECK(empty_fixed_array()->IsFixedArray());
+ if (length == 0) return empty_fixed_array();
+
+ DCHECK(!InNewSpace(filler));
+ HeapObject* result;
+ {
+ AllocationResult allocation = AllocateRawFixedArray(length, pretenure);
+ if (!allocation.To(&result)) return allocation;
+ }
+
+ result->set_map_no_write_barrier(fixed_array_map());
+ FixedArray* array = FixedArray::cast(result);
+ array->set_length(length);
+ MemsetPointer(array->data_start(), filler, length);
+ return array;
+}
+
+
+AllocationResult Heap::AllocateFixedArray(int length, PretenureFlag pretenure) {
+ return AllocateFixedArrayWithFiller(length, pretenure, undefined_value());
+}
+
+
+AllocationResult Heap::AllocateUninitializedFixedArray(int length) {
+ if (length == 0) return empty_fixed_array();
+
+ HeapObject* obj;
+ {
+ AllocationResult allocation = AllocateRawFixedArray(length, NOT_TENURED);
+ if (!allocation.To(&obj)) return allocation;
+ }
+
+ obj->set_map_no_write_barrier(fixed_array_map());
+ FixedArray::cast(obj)->set_length(length);
+ return obj;
+}
+
+
+AllocationResult Heap::AllocateUninitializedFixedDoubleArray(
+ int length, PretenureFlag pretenure) {
+ if (length == 0) return empty_fixed_array();
+
+ HeapObject* elements;
+ AllocationResult allocation = AllocateRawFixedDoubleArray(length, pretenure);
+ if (!allocation.To(&elements)) return allocation;
+
+ elements->set_map_no_write_barrier(fixed_double_array_map());
+ FixedDoubleArray::cast(elements)->set_length(length);
+ return elements;
+}
+
+
+AllocationResult Heap::AllocateRawFixedDoubleArray(int length,
+ PretenureFlag pretenure) {
+ if (length < 0 || length > FixedDoubleArray::kMaxLength) {
+ v8::internal::Heap::FatalProcessOutOfMemory("invalid array length", true);
+ }
+ int size = FixedDoubleArray::SizeFor(length);
+#ifndef V8_HOST_ARCH_64_BIT
+ size += kPointerSize;
+#endif
+ AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, pretenure);
+
+ HeapObject* object;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+ if (!allocation.To(&object)) return allocation;
+ }
+
+ return EnsureDoubleAligned(this, object, size);
+}
+
+
+AllocationResult Heap::AllocateConstantPoolArray(
+ const ConstantPoolArray::NumberOfEntries& small) {
+ CHECK(small.are_in_range(0, ConstantPoolArray::kMaxSmallEntriesPerType));
+ int size = ConstantPoolArray::SizeFor(small);
+#ifndef V8_HOST_ARCH_64_BIT
+ size += kPointerSize;
+#endif
+ AllocationSpace space = SelectSpace(size, OLD_POINTER_SPACE, TENURED);
+
+ HeapObject* object;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_POINTER_SPACE);
+ if (!allocation.To(&object)) return allocation;
+ }
+ object = EnsureDoubleAligned(this, object, size);
+ object->set_map_no_write_barrier(constant_pool_array_map());
+
+ ConstantPoolArray* constant_pool = ConstantPoolArray::cast(object);
+ constant_pool->Init(small);
+ constant_pool->ClearPtrEntries(isolate());
+ return constant_pool;
+}
+
+
+AllocationResult Heap::AllocateExtendedConstantPoolArray(
+ const ConstantPoolArray::NumberOfEntries& small,
+ const ConstantPoolArray::NumberOfEntries& extended) {
+ CHECK(small.are_in_range(0, ConstantPoolArray::kMaxSmallEntriesPerType));
+ CHECK(extended.are_in_range(0, kMaxInt));
+ int size = ConstantPoolArray::SizeForExtended(small, extended);
+#ifndef V8_HOST_ARCH_64_BIT
+ size += kPointerSize;
+#endif
+ AllocationSpace space = SelectSpace(size, OLD_POINTER_SPACE, TENURED);
+
+ HeapObject* object;
+ {
+ AllocationResult allocation = AllocateRaw(size, space, OLD_POINTER_SPACE);
+ if (!allocation.To(&object)) return allocation;
+ }
+ object = EnsureDoubleAligned(this, object, size);
+ object->set_map_no_write_barrier(constant_pool_array_map());
+
+ ConstantPoolArray* constant_pool = ConstantPoolArray::cast(object);
+ constant_pool->InitExtended(small, extended);
+ constant_pool->ClearPtrEntries(isolate());
+ return constant_pool;
+}
+
+
+AllocationResult Heap::AllocateEmptyConstantPoolArray() {
+ ConstantPoolArray::NumberOfEntries small(0, 0, 0, 0);
+ int size = ConstantPoolArray::SizeFor(small);
+ HeapObject* result;
+ {
+ AllocationResult allocation =
+ AllocateRaw(size, OLD_DATA_SPACE, OLD_DATA_SPACE);
+ if (!allocation.To(&result)) return allocation;
+ }
+ result->set_map_no_write_barrier(constant_pool_array_map());
+ ConstantPoolArray::cast(result)->Init(small);
+ return result;
+}
+
+
+AllocationResult Heap::AllocateSymbol() {
+ // Statically ensure that it is safe to allocate symbols in paged spaces.
+ STATIC_ASSERT(Symbol::kSize <= Page::kMaxRegularHeapObjectSize);
+
+ HeapObject* result;
+ AllocationResult allocation =
+ AllocateRaw(Symbol::kSize, OLD_POINTER_SPACE, OLD_POINTER_SPACE);
+ if (!allocation.To(&result)) return allocation;
+
+ result->set_map_no_write_barrier(symbol_map());
+
+ // Generate a random hash value.
+ int hash;
+ int attempts = 0;
+ do {
+ hash = isolate()->random_number_generator()->NextInt() & Name::kHashBitMask;
+ attempts++;
+ } while (hash == 0 && attempts < 30);
+ if (hash == 0) hash = 1; // never return 0
+
+ Symbol::cast(result)
+ ->set_hash_field(Name::kIsNotArrayIndexMask | (hash << Name::kHashShift));
+ Symbol::cast(result)->set_name(undefined_value());
+ Symbol::cast(result)->set_flags(Smi::FromInt(0));
+
+ DCHECK(!Symbol::cast(result)->is_private());
+ return result;
+}
+
+
+AllocationResult Heap::AllocateStruct(InstanceType type) {
+ Map* map;
+ switch (type) {
+#define MAKE_CASE(NAME, Name, name) \
+ case NAME##_TYPE: \
+ map = name##_map(); \
+ break;
+ STRUCT_LIST(MAKE_CASE)
+#undef MAKE_CASE
+ default:
+ UNREACHABLE();
+ return exception();
+ }
+ int size = map->instance_size();
+ AllocationSpace space = SelectSpace(size, OLD_POINTER_SPACE, TENURED);
+ Struct* result;
+ {
+ AllocationResult allocation = Allocate(map, space);
+ if (!allocation.To(&result)) return allocation;
+ }
+ result->InitializeBody(size);
+ return result;
+}
+
+
+bool Heap::IsHeapIterable() {
+ // TODO(hpayer): This function is not correct. Allocation folding in old
+ // space breaks the iterability.
+ return new_space_top_after_last_gc_ == new_space()->top();
+}
+
+
+void Heap::MakeHeapIterable() {
+ DCHECK(AllowHeapAllocation::IsAllowed());
+ if (!IsHeapIterable()) {
+ CollectAllGarbage(kMakeHeapIterableMask, "Heap::MakeHeapIterable");
+ }
+ if (mark_compact_collector()->sweeping_in_progress()) {
+ mark_compact_collector()->EnsureSweepingCompleted();
+ }
+ DCHECK(IsHeapIterable());
+}
+
+
+void Heap::IdleMarkCompact(const char* message) {
+ bool uncommit = false;
+ if (gc_count_at_last_idle_gc_ == gc_count_) {
+ // No GC since the last full GC, the mutator is probably not active.
+ isolate_->compilation_cache()->Clear();
+ uncommit = true;
+ }
+ CollectAllGarbage(kReduceMemoryFootprintMask, message);
+ gc_idle_time_handler_.NotifyIdleMarkCompact();
+ gc_count_at_last_idle_gc_ = gc_count_;
+ if (uncommit) {
+ new_space_.Shrink();
+ UncommitFromSpace();
+ }
+}
+
+
+void Heap::AdvanceIdleIncrementalMarking(intptr_t step_size) {
+ incremental_marking()->Step(step_size,
+ IncrementalMarking::NO_GC_VIA_STACK_GUARD, true);
+
+ if (incremental_marking()->IsComplete()) {
+ IdleMarkCompact("idle notification: finalize incremental");
+ }
+}
+
+
+bool Heap::WorthActivatingIncrementalMarking() {
+ return incremental_marking()->IsStopped() &&
+ incremental_marking()->WorthActivating() && NextGCIsLikelyToBeFull();
+}
+
+
+bool Heap::IdleNotification(int idle_time_in_ms) {
+ // If incremental marking is off, we do not perform idle notification.
+ if (!FLAG_incremental_marking) return true;
+ base::ElapsedTimer timer;
+ timer.Start();
+ isolate()->counters()->gc_idle_time_allotted_in_ms()->AddSample(
+ idle_time_in_ms);
+ HistogramTimerScope idle_notification_scope(
+ isolate_->counters()->gc_idle_notification());
+
+ GCIdleTimeHandler::HeapState heap_state;
+ heap_state.contexts_disposed = contexts_disposed_;
+ heap_state.size_of_objects = static_cast<size_t>(SizeOfObjects());
+ heap_state.incremental_marking_stopped = incremental_marking()->IsStopped();
+ // TODO(ulan): Start incremental marking only for large heaps.
+ heap_state.can_start_incremental_marking =
+ incremental_marking()->ShouldActivate();
+ heap_state.sweeping_in_progress =
+ mark_compact_collector()->sweeping_in_progress();
+ heap_state.mark_compact_speed_in_bytes_per_ms =
+ static_cast<size_t>(tracer()->MarkCompactSpeedInBytesPerMillisecond());
+ heap_state.incremental_marking_speed_in_bytes_per_ms = static_cast<size_t>(
+ tracer()->IncrementalMarkingSpeedInBytesPerMillisecond());
+ heap_state.scavenge_speed_in_bytes_per_ms =
+ static_cast<size_t>(tracer()->ScavengeSpeedInBytesPerMillisecond());
+ heap_state.available_new_space_memory = new_space_.Available();
+ heap_state.new_space_capacity = new_space_.Capacity();
+ heap_state.new_space_allocation_throughput_in_bytes_per_ms =
+ static_cast<size_t>(
+ tracer()->NewSpaceAllocationThroughputInBytesPerMillisecond());
+
+ GCIdleTimeAction action =
+ gc_idle_time_handler_.Compute(idle_time_in_ms, heap_state);
+
+ bool result = false;
+ switch (action.type) {
+ case DONE:
+ result = true;
+ break;
+ case DO_INCREMENTAL_MARKING:
+ if (incremental_marking()->IsStopped()) {
+ incremental_marking()->Start();
+ }
+ AdvanceIdleIncrementalMarking(action.parameter);
+ break;
+ case DO_FULL_GC: {
+ HistogramTimerScope scope(isolate_->counters()->gc_context());
+ if (contexts_disposed_) {
+ CollectAllGarbage(kReduceMemoryFootprintMask,
+ "idle notification: contexts disposed");
+ gc_idle_time_handler_.NotifyIdleMarkCompact();
+ gc_count_at_last_idle_gc_ = gc_count_;
+ } else {
+ IdleMarkCompact("idle notification: finalize idle round");
+ }
+ break;
+ }
+ case DO_SCAVENGE:
+ CollectGarbage(NEW_SPACE, "idle notification: scavenge");
+ break;
+ case DO_FINALIZE_SWEEPING:
+ mark_compact_collector()->EnsureSweepingCompleted();
+ break;
+ case DO_NOTHING:
+ break;
+ }
+
+ int actual_time_ms = static_cast<int>(timer.Elapsed().InMilliseconds());
+ if (actual_time_ms <= idle_time_in_ms) {
+ isolate()->counters()->gc_idle_time_limit_undershot()->AddSample(
+ idle_time_in_ms - actual_time_ms);
+ } else {
+ isolate()->counters()->gc_idle_time_limit_overshot()->AddSample(
+ actual_time_ms - idle_time_in_ms);
+ }
+
+ if (FLAG_trace_idle_notification) {
+ PrintF("Idle notification: requested idle time %d ms, actual time %d ms [",
+ idle_time_in_ms, actual_time_ms);
+ action.Print();
+ PrintF("]\n");
+ }
+
+ contexts_disposed_ = 0;
+ return result;
+}
+
+
+#ifdef DEBUG
+
+void Heap::Print() {
+ if (!HasBeenSetUp()) return;
+ isolate()->PrintStack(stdout);
+ AllSpaces spaces(this);
+ for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
+ space->Print();
+ }
+}
+
+
+void Heap::ReportCodeStatistics(const char* title) {
+ PrintF(">>>>>> Code Stats (%s) >>>>>>\n", title);
+ PagedSpace::ResetCodeStatistics(isolate());
+ // We do not look for code in new space, map space, or old space. If code
+ // somehow ends up in those spaces, we would miss it here.
+ code_space_->CollectCodeStatistics();
+ lo_space_->CollectCodeStatistics();
+ PagedSpace::ReportCodeStatistics(isolate());
+}
+
+
+// This function expects that NewSpace's allocated objects histogram is
+// populated (via a call to CollectStatistics or else as a side effect of a
+// just-completed scavenge collection).
+void Heap::ReportHeapStatistics(const char* title) {
+ USE(title);
+ PrintF(">>>>>> =============== %s (%d) =============== >>>>>>\n", title,
+ gc_count_);
+ PrintF("old_generation_allocation_limit_ %" V8_PTR_PREFIX "d\n",
+ old_generation_allocation_limit_);
+
+ PrintF("\n");
+ PrintF("Number of handles : %d\n", HandleScope::NumberOfHandles(isolate_));
+ isolate_->global_handles()->PrintStats();
+ PrintF("\n");
+
+ PrintF("Heap statistics : ");
+ isolate_->memory_allocator()->ReportStatistics();
+ PrintF("To space : ");
+ new_space_.ReportStatistics();
+ PrintF("Old pointer space : ");
+ old_pointer_space_->ReportStatistics();
+ PrintF("Old data space : ");
+ old_data_space_->ReportStatistics();
+ PrintF("Code space : ");
+ code_space_->ReportStatistics();
+ PrintF("Map space : ");
+ map_space_->ReportStatistics();
+ PrintF("Cell space : ");
+ cell_space_->ReportStatistics();
+ PrintF("PropertyCell space : ");
+ property_cell_space_->ReportStatistics();
+ PrintF("Large object space : ");
+ lo_space_->ReportStatistics();
+ PrintF(">>>>>> ========================================= >>>>>>\n");
+}
+
+#endif // DEBUG
+
+bool Heap::Contains(HeapObject* value) { return Contains(value->address()); }
+
+
+bool Heap::Contains(Address addr) {
+ if (isolate_->memory_allocator()->IsOutsideAllocatedSpace(addr)) return false;
+ return HasBeenSetUp() &&
+ (new_space_.ToSpaceContains(addr) ||
+ old_pointer_space_->Contains(addr) ||
+ old_data_space_->Contains(addr) || code_space_->Contains(addr) ||
+ map_space_->Contains(addr) || cell_space_->Contains(addr) ||
+ property_cell_space_->Contains(addr) ||
+ lo_space_->SlowContains(addr));
+}
+
+
+bool Heap::InSpace(HeapObject* value, AllocationSpace space) {
+ return InSpace(value->address(), space);
+}
+
+
+bool Heap::InSpace(Address addr, AllocationSpace space) {
+ if (isolate_->memory_allocator()->IsOutsideAllocatedSpace(addr)) return false;
+ if (!HasBeenSetUp()) return false;
+
+ switch (space) {
+ case NEW_SPACE:
+ return new_space_.ToSpaceContains(addr);
+ case OLD_POINTER_SPACE:
+ return old_pointer_space_->Contains(addr);
+ case OLD_DATA_SPACE:
+ return old_data_space_->Contains(addr);
+ case CODE_SPACE:
+ return code_space_->Contains(addr);
+ case MAP_SPACE:
+ return map_space_->Contains(addr);
+ case CELL_SPACE:
+ return cell_space_->Contains(addr);
+ case PROPERTY_CELL_SPACE:
+ return property_cell_space_->Contains(addr);
+ case LO_SPACE:
+ return lo_space_->SlowContains(addr);
+ case INVALID_SPACE:
+ break;
+ }
+ UNREACHABLE();
+ return false;
+}
+
+
+#ifdef VERIFY_HEAP
+void Heap::Verify() {
+ CHECK(HasBeenSetUp());
+ HandleScope scope(isolate());
+
+ store_buffer()->Verify();
+
+ if (mark_compact_collector()->sweeping_in_progress()) {
+ // We have to wait here for the sweeper threads to have an iterable heap.
+ mark_compact_collector()->EnsureSweepingCompleted();
+ }
+
+ VerifyPointersVisitor visitor;
+ IterateRoots(&visitor, VISIT_ONLY_STRONG);
+
+ VerifySmisVisitor smis_visitor;
+ IterateSmiRoots(&smis_visitor);
+
+ new_space_.Verify();
+
+ old_pointer_space_->Verify(&visitor);
+ map_space_->Verify(&visitor);
+
+ VerifyPointersVisitor no_dirty_regions_visitor;
+ old_data_space_->Verify(&no_dirty_regions_visitor);
+ code_space_->Verify(&no_dirty_regions_visitor);
+ cell_space_->Verify(&no_dirty_regions_visitor);
+ property_cell_space_->Verify(&no_dirty_regions_visitor);
+
+ lo_space_->Verify();
+}
+#endif
+
+
+void Heap::ZapFromSpace() {
+ NewSpacePageIterator it(new_space_.FromSpaceStart(),
+ new_space_.FromSpaceEnd());
+ while (it.has_next()) {
+ NewSpacePage* page = it.next();
+ for (Address cursor = page->area_start(), limit = page->area_end();
+ cursor < limit; cursor += kPointerSize) {
+ Memory::Address_at(cursor) = kFromSpaceZapValue;
+ }
+ }
+}
+
+
+void Heap::IterateAndMarkPointersToFromSpace(Address start, Address end,
+ ObjectSlotCallback callback) {
+ Address slot_address = start;
+
+ // We are not collecting slots on new space objects during mutation
+ // thus we have to scan for pointers to evacuation candidates when we
+ // promote objects. But we should not record any slots in non-black
+ // objects. Grey object's slots would be rescanned.
+ // White object might not survive until the end of collection
+ // it would be a violation of the invariant to record it's slots.
+ bool record_slots = false;
+ if (incremental_marking()->IsCompacting()) {
+ MarkBit mark_bit = Marking::MarkBitFrom(HeapObject::FromAddress(start));
+ record_slots = Marking::IsBlack(mark_bit);
+ }
+
+ while (slot_address < end) {
+ Object** slot = reinterpret_cast<Object**>(slot_address);
+ Object* object = *slot;
+ // If the store buffer becomes overfull we mark pages as being exempt from
+ // the store buffer. These pages are scanned to find pointers that point
+ // to the new space. In that case we may hit newly promoted objects and
+ // fix the pointers before the promotion queue gets to them. Thus the 'if'.
+ if (object->IsHeapObject()) {
+ if (Heap::InFromSpace(object)) {
+ callback(reinterpret_cast<HeapObject**>(slot),
+ HeapObject::cast(object));
+ Object* new_object = *slot;
+ if (InNewSpace(new_object)) {
+ SLOW_DCHECK(Heap::InToSpace(new_object));
+ SLOW_DCHECK(new_object->IsHeapObject());
+ store_buffer_.EnterDirectlyIntoStoreBuffer(
+ reinterpret_cast<Address>(slot));
+ }
+ SLOW_DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_object));
+ } else if (record_slots &&
+ MarkCompactCollector::IsOnEvacuationCandidate(object)) {
+ mark_compact_collector()->RecordSlot(slot, slot, object);
+ }
+ }
+ slot_address += kPointerSize;
+ }
+}
+
+
+#ifdef DEBUG
+typedef bool (*CheckStoreBufferFilter)(Object** addr);
+
+
+bool IsAMapPointerAddress(Object** addr) {
+ uintptr_t a = reinterpret_cast<uintptr_t>(addr);
+ int mod = a % Map::kSize;
+ return mod >= Map::kPointerFieldsBeginOffset &&
+ mod < Map::kPointerFieldsEndOffset;
+}
+
+
+bool EverythingsAPointer(Object** addr) { return true; }
+
+
+static void CheckStoreBuffer(Heap* heap, Object** current, Object** limit,
+ Object**** store_buffer_position,
+ Object*** store_buffer_top,
+ CheckStoreBufferFilter filter,
+ Address special_garbage_start,
+ Address special_garbage_end) {
+ Map* free_space_map = heap->free_space_map();
+ for (; current < limit; current++) {
+ Object* o = *current;
+ Address current_address = reinterpret_cast<Address>(current);
+ // Skip free space.
+ if (o == free_space_map) {
+ Address current_address = reinterpret_cast<Address>(current);
+ FreeSpace* free_space =
+ FreeSpace::cast(HeapObject::FromAddress(current_address));
+ int skip = free_space->Size();
+ DCHECK(current_address + skip <= reinterpret_cast<Address>(limit));
+ DCHECK(skip > 0);
+ current_address += skip - kPointerSize;
+ current = reinterpret_cast<Object**>(current_address);
+ continue;
+ }
+ // Skip the current linear allocation space between top and limit which is
+ // unmarked with the free space map, but can contain junk.
+ if (current_address == special_garbage_start &&
+ special_garbage_end != special_garbage_start) {
+ current_address = special_garbage_end - kPointerSize;
+ current = reinterpret_cast<Object**>(current_address);
+ continue;
+ }
+ if (!(*filter)(current)) continue;
+ DCHECK(current_address < special_garbage_start ||
+ current_address >= special_garbage_end);
+ DCHECK(reinterpret_cast<uintptr_t>(o) != kFreeListZapValue);
+ // We have to check that the pointer does not point into new space
+ // without trying to cast it to a heap object since the hash field of
+ // a string can contain values like 1 and 3 which are tagged null
+ // pointers.
+ if (!heap->InNewSpace(o)) continue;
+ while (**store_buffer_position < current &&
+ *store_buffer_position < store_buffer_top) {
+ (*store_buffer_position)++;
+ }
+ if (**store_buffer_position != current ||
+ *store_buffer_position == store_buffer_top) {
+ Object** obj_start = current;
+ while (!(*obj_start)->IsMap()) obj_start--;
+ UNREACHABLE();
+ }
+ }
+}
+
+
+// Check that the store buffer contains all intergenerational pointers by
+// scanning a page and ensuring that all pointers to young space are in the
+// store buffer.
+void Heap::OldPointerSpaceCheckStoreBuffer() {
+ OldSpace* space = old_pointer_space();
+ PageIterator pages(space);
+
+ store_buffer()->SortUniq();
+
+ while (pages.has_next()) {
+ Page* page = pages.next();
+ Object** current = reinterpret_cast<Object**>(page->area_start());
+
+ Address end = page->area_end();
+
+ Object*** store_buffer_position = store_buffer()->Start();
+ Object*** store_buffer_top = store_buffer()->Top();
+
+ Object** limit = reinterpret_cast<Object**>(end);
+ CheckStoreBuffer(this, current, limit, &store_buffer_position,
+ store_buffer_top, &EverythingsAPointer, space->top(),
+ space->limit());
+ }
+}
+
+
+void Heap::MapSpaceCheckStoreBuffer() {
+ MapSpace* space = map_space();
+ PageIterator pages(space);
+
+ store_buffer()->SortUniq();
+
+ while (pages.has_next()) {
+ Page* page = pages.next();
+ Object** current = reinterpret_cast<Object**>(page->area_start());
+
+ Address end = page->area_end();
+
+ Object*** store_buffer_position = store_buffer()->Start();
+ Object*** store_buffer_top = store_buffer()->Top();
+
+ Object** limit = reinterpret_cast<Object**>(end);
+ CheckStoreBuffer(this, current, limit, &store_buffer_position,
+ store_buffer_top, &IsAMapPointerAddress, space->top(),
+ space->limit());
+ }
+}
+
+
+void Heap::LargeObjectSpaceCheckStoreBuffer() {
+ LargeObjectIterator it(lo_space());
+ for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) {
+ // We only have code, sequential strings, or fixed arrays in large
+ // object space, and only fixed arrays can possibly contain pointers to
+ // the young generation.
+ if (object->IsFixedArray()) {
+ Object*** store_buffer_position = store_buffer()->Start();
+ Object*** store_buffer_top = store_buffer()->Top();
+ Object** current = reinterpret_cast<Object**>(object->address());
+ Object** limit =
+ reinterpret_cast<Object**>(object->address() + object->Size());
+ CheckStoreBuffer(this, current, limit, &store_buffer_position,
+ store_buffer_top, &EverythingsAPointer, NULL, NULL);
+ }
+ }
+}
+#endif
+
+
+void Heap::IterateRoots(ObjectVisitor* v, VisitMode mode) {
+ IterateStrongRoots(v, mode);
+ IterateWeakRoots(v, mode);
+}
+
+
+void Heap::IterateWeakRoots(ObjectVisitor* v, VisitMode mode) {
+ v->VisitPointer(reinterpret_cast<Object**>(&roots_[kStringTableRootIndex]));
+ v->Synchronize(VisitorSynchronization::kStringTable);
+ if (mode != VISIT_ALL_IN_SCAVENGE && mode != VISIT_ALL_IN_SWEEP_NEWSPACE) {
+ // Scavenge collections have special processing for this.
+ external_string_table_.Iterate(v);
+ }
+ v->Synchronize(VisitorSynchronization::kExternalStringsTable);
+}
+
+
+void Heap::IterateSmiRoots(ObjectVisitor* v) {
+ // Acquire execution access since we are going to read stack limit values.
+ ExecutionAccess access(isolate());
+ v->VisitPointers(&roots_[kSmiRootsStart], &roots_[kRootListLength]);
+ v->Synchronize(VisitorSynchronization::kSmiRootList);
+}
+
+
+void Heap::IterateStrongRoots(ObjectVisitor* v, VisitMode mode) {
+ v->VisitPointers(&roots_[0], &roots_[kStrongRootListLength]);
+ v->Synchronize(VisitorSynchronization::kStrongRootList);
+
+ v->VisitPointer(bit_cast<Object**>(&hidden_string_));
+ v->Synchronize(VisitorSynchronization::kInternalizedString);
+
+ isolate_->bootstrapper()->Iterate(v);
+ v->Synchronize(VisitorSynchronization::kBootstrapper);
+ isolate_->Iterate(v);
+ v->Synchronize(VisitorSynchronization::kTop);
+ Relocatable::Iterate(isolate_, v);
+ v->Synchronize(VisitorSynchronization::kRelocatable);
+
+ if (isolate_->deoptimizer_data() != NULL) {
+ isolate_->deoptimizer_data()->Iterate(v);
+ }
+ v->Synchronize(VisitorSynchronization::kDebug);
+ isolate_->compilation_cache()->Iterate(v);
+ v->Synchronize(VisitorSynchronization::kCompilationCache);
+
+ // Iterate over local handles in handle scopes.
+ isolate_->handle_scope_implementer()->Iterate(v);
+ isolate_->IterateDeferredHandles(v);
+ v->Synchronize(VisitorSynchronization::kHandleScope);
+
+ // Iterate over the builtin code objects and code stubs in the
+ // heap. Note that it is not necessary to iterate over code objects
+ // on scavenge collections.
+ if (mode != VISIT_ALL_IN_SCAVENGE) {
+ isolate_->builtins()->IterateBuiltins(v);
+ }
+ v->Synchronize(VisitorSynchronization::kBuiltins);
+
+ // Iterate over global handles.
+ switch (mode) {
+ case VISIT_ONLY_STRONG:
+ isolate_->global_handles()->IterateStrongRoots(v);
+ break;
+ case VISIT_ALL_IN_SCAVENGE:
+ isolate_->global_handles()->IterateNewSpaceStrongAndDependentRoots(v);
+ break;
+ case VISIT_ALL_IN_SWEEP_NEWSPACE:
+ case VISIT_ALL:
+ isolate_->global_handles()->IterateAllRoots(v);
+ break;
+ }
+ v->Synchronize(VisitorSynchronization::kGlobalHandles);
+
+ // Iterate over eternal handles.
+ if (mode == VISIT_ALL_IN_SCAVENGE) {
+ isolate_->eternal_handles()->IterateNewSpaceRoots(v);
+ } else {
+ isolate_->eternal_handles()->IterateAllRoots(v);
+ }
+ v->Synchronize(VisitorSynchronization::kEternalHandles);
+
+ // Iterate over pointers being held by inactive threads.
+ isolate_->thread_manager()->Iterate(v);
+ v->Synchronize(VisitorSynchronization::kThreadManager);
+
+ // Iterate over the pointers the Serialization/Deserialization code is
+ // holding.
+ // During garbage collection this keeps the partial snapshot cache alive.
+ // During deserialization of the startup snapshot this creates the partial
+ // snapshot cache and deserializes the objects it refers to. During
+ // serialization this does nothing, since the partial snapshot cache is
+ // empty. However the next thing we do is create the partial snapshot,
+ // filling up the partial snapshot cache with objects it needs as we go.
+ SerializerDeserializer::Iterate(isolate_, v);
+ // We don't do a v->Synchronize call here, because in debug mode that will
+ // output a flag to the snapshot. However at this point the serializer and
+ // deserializer are deliberately a little unsynchronized (see above) so the
+ // checking of the sync flag in the snapshot would fail.
+}
+
+
+// TODO(1236194): Since the heap size is configurable on the command line
+// and through the API, we should gracefully handle the case that the heap
+// size is not big enough to fit all the initial objects.
+bool Heap::ConfigureHeap(int max_semi_space_size, int max_old_space_size,
+ int max_executable_size, size_t code_range_size) {
+ if (HasBeenSetUp()) return false;
+
+ // Overwrite default configuration.
+ if (max_semi_space_size > 0) {
+ max_semi_space_size_ = max_semi_space_size * MB;
+ }
+ if (max_old_space_size > 0) {
+ max_old_generation_size_ = max_old_space_size * MB;
+ }
+ if (max_executable_size > 0) {
+ max_executable_size_ = max_executable_size * MB;
+ }
+
+ // If max space size flags are specified overwrite the configuration.
+ if (FLAG_max_semi_space_size > 0) {
+ max_semi_space_size_ = FLAG_max_semi_space_size * MB;
+ }
+ if (FLAG_max_old_space_size > 0) {
+ max_old_generation_size_ = FLAG_max_old_space_size * MB;
+ }
+ if (FLAG_max_executable_size > 0) {
+ max_executable_size_ = FLAG_max_executable_size * MB;
+ }
+
+ if (FLAG_stress_compaction) {
+ // This will cause more frequent GCs when stressing.
+ max_semi_space_size_ = Page::kPageSize;
+ }
+
+ if (Snapshot::HaveASnapshotToStartFrom()) {
+ // If we are using a snapshot we always reserve the default amount
+ // of memory for each semispace because code in the snapshot has
+ // write-barrier code that relies on the size and alignment of new
+ // space. We therefore cannot use a larger max semispace size
+ // than the default reserved semispace size.
+ if (max_semi_space_size_ > reserved_semispace_size_) {
+ max_semi_space_size_ = reserved_semispace_size_;
+ if (FLAG_trace_gc) {
+ PrintPID("Max semi-space size cannot be more than %d kbytes\n",
+ reserved_semispace_size_ >> 10);
+ }
+ }
+ } else {
+ // If we are not using snapshots we reserve space for the actual
+ // max semispace size.
+ reserved_semispace_size_ = max_semi_space_size_;
+ }
+
+ // The max executable size must be less than or equal to the max old
+ // generation size.
+ if (max_executable_size_ > max_old_generation_size_) {
+ max_executable_size_ = max_old_generation_size_;
+ }
+
+ // The new space size must be a power of two to support single-bit testing
+ // for containment.
+ max_semi_space_size_ =
+ base::bits::RoundUpToPowerOfTwo32(max_semi_space_size_);
+ reserved_semispace_size_ =
+ base::bits::RoundUpToPowerOfTwo32(reserved_semispace_size_);
+
+ if (FLAG_min_semi_space_size > 0) {
+ int initial_semispace_size = FLAG_min_semi_space_size * MB;
+ if (initial_semispace_size > max_semi_space_size_) {
+ initial_semispace_size_ = max_semi_space_size_;
+ if (FLAG_trace_gc) {
+ PrintPID(
+ "Min semi-space size cannot be more than the maximum"
+ "semi-space size of %d MB\n",
+ max_semi_space_size_);
+ }
+ } else {
+ initial_semispace_size_ = initial_semispace_size;
+ }
+ }
+
+ initial_semispace_size_ = Min(initial_semispace_size_, max_semi_space_size_);
+
+ // The old generation is paged and needs at least one page for each space.
+ int paged_space_count = LAST_PAGED_SPACE - FIRST_PAGED_SPACE + 1;
+ max_old_generation_size_ =
+ Max(static_cast<intptr_t>(paged_space_count * Page::kPageSize),
+ max_old_generation_size_);
+
+ // We rely on being able to allocate new arrays in paged spaces.
+ DCHECK(Page::kMaxRegularHeapObjectSize >=
+ (JSArray::kSize +
+ FixedArray::SizeFor(JSObject::kInitialMaxFastElementArray) +
+ AllocationMemento::kSize));
+
+ code_range_size_ = code_range_size * MB;
+
+ configured_ = true;
+ return true;
+}
+
+
+bool Heap::ConfigureHeapDefault() { return ConfigureHeap(0, 0, 0, 0); }
+
+
+void Heap::RecordStats(HeapStats* stats, bool take_snapshot) {
+ *stats->start_marker = HeapStats::kStartMarker;
+ *stats->end_marker = HeapStats::kEndMarker;
+ *stats->new_space_size = new_space_.SizeAsInt();
+ *stats->new_space_capacity = static_cast<int>(new_space_.Capacity());
+ *stats->old_pointer_space_size = old_pointer_space_->SizeOfObjects();
+ *stats->old_pointer_space_capacity = old_pointer_space_->Capacity();
+ *stats->old_data_space_size = old_data_space_->SizeOfObjects();
+ *stats->old_data_space_capacity = old_data_space_->Capacity();
+ *stats->code_space_size = code_space_->SizeOfObjects();
+ *stats->code_space_capacity = code_space_->Capacity();
+ *stats->map_space_size = map_space_->SizeOfObjects();
+ *stats->map_space_capacity = map_space_->Capacity();
+ *stats->cell_space_size = cell_space_->SizeOfObjects();
+ *stats->cell_space_capacity = cell_space_->Capacity();
+ *stats->property_cell_space_size = property_cell_space_->SizeOfObjects();
+ *stats->property_cell_space_capacity = property_cell_space_->Capacity();
+ *stats->lo_space_size = lo_space_->Size();
+ isolate_->global_handles()->RecordStats(stats);
+ *stats->memory_allocator_size = isolate()->memory_allocator()->Size();
+ *stats->memory_allocator_capacity =
+ isolate()->memory_allocator()->Size() +
+ isolate()->memory_allocator()->Available();
+ *stats->os_error = base::OS::GetLastError();
+ isolate()->memory_allocator()->Available();
+ if (take_snapshot) {
+ HeapIterator iterator(this);
+ for (HeapObject* obj = iterator.next(); obj != NULL;
+ obj = iterator.next()) {
+ InstanceType type = obj->map()->instance_type();
+ DCHECK(0 <= type && type <= LAST_TYPE);
+ stats->objects_per_type[type]++;
+ stats->size_per_type[type] += obj->Size();
+ }
+ }
+}
+
+
+intptr_t Heap::PromotedSpaceSizeOfObjects() {
+ return old_pointer_space_->SizeOfObjects() +
+ old_data_space_->SizeOfObjects() + code_space_->SizeOfObjects() +
+ map_space_->SizeOfObjects() + cell_space_->SizeOfObjects() +
+ property_cell_space_->SizeOfObjects() + lo_space_->SizeOfObjects();
+}
+
+
+int64_t Heap::PromotedExternalMemorySize() {
+ if (amount_of_external_allocated_memory_ <=
+ amount_of_external_allocated_memory_at_last_global_gc_)
+ return 0;
+ return amount_of_external_allocated_memory_ -
+ amount_of_external_allocated_memory_at_last_global_gc_;
+}
+
+
+intptr_t Heap::OldGenerationAllocationLimit(intptr_t old_gen_size,
+ int freed_global_handles) {
+ const int kMaxHandles = 1000;
+ const int kMinHandles = 100;
+ double min_factor = 1.1;
+ double max_factor = 4;
+ // We set the old generation growing factor to 2 to grow the heap slower on
+ // memory-constrained devices.
+ if (max_old_generation_size_ <= kMaxOldSpaceSizeMediumMemoryDevice) {
+ max_factor = 2;
+ }
+ // If there are many freed global handles, then the next full GC will
+ // likely collect a lot of garbage. Choose the heap growing factor
+ // depending on freed global handles.
+ // TODO(ulan, hpayer): Take into account mutator utilization.
+ double factor;
+ if (freed_global_handles <= kMinHandles) {
+ factor = max_factor;
+ } else if (freed_global_handles >= kMaxHandles) {
+ factor = min_factor;
+ } else {
+ // Compute factor using linear interpolation between points
+ // (kMinHandles, max_factor) and (kMaxHandles, min_factor).
+ factor = max_factor -
+ (freed_global_handles - kMinHandles) * (max_factor - min_factor) /
+ (kMaxHandles - kMinHandles);
+ }
+
+ if (FLAG_stress_compaction ||
+ mark_compact_collector()->reduce_memory_footprint_) {
+ factor = min_factor;
+ }
+
+ intptr_t limit = static_cast<intptr_t>(old_gen_size * factor);
+ limit = Max(limit, kMinimumOldGenerationAllocationLimit);
+ limit += new_space_.Capacity();
+ intptr_t halfway_to_the_max = (old_gen_size + max_old_generation_size_) / 2;
+ return Min(limit, halfway_to_the_max);
+}
+
+
+void Heap::EnableInlineAllocation() {
+ if (!inline_allocation_disabled_) return;
+ inline_allocation_disabled_ = false;
+
+ // Update inline allocation limit for new space.
+ new_space()->UpdateInlineAllocationLimit(0);
+}
+
+
+void Heap::DisableInlineAllocation() {
+ if (inline_allocation_disabled_) return;
+ inline_allocation_disabled_ = true;
+
+ // Update inline allocation limit for new space.
+ new_space()->UpdateInlineAllocationLimit(0);
+
+ // Update inline allocation limit for old spaces.
+ PagedSpaces spaces(this);
+ for (PagedSpace* space = spaces.next(); space != NULL;
+ space = spaces.next()) {
+ space->EmptyAllocationInfo();
+ }
+}
+
+
+V8_DECLARE_ONCE(initialize_gc_once);
+
+static void InitializeGCOnce() {
+ InitializeScavengingVisitorsTables();
+ NewSpaceScavenger::Initialize();
+ MarkCompactCollector::Initialize();
+}
+
+
+bool Heap::SetUp() {
+#ifdef DEBUG
+ allocation_timeout_ = FLAG_gc_interval;
+#endif
+
+ // Initialize heap spaces and initial maps and objects. Whenever something
+ // goes wrong, just return false. The caller should check the results and
+ // call Heap::TearDown() to release allocated memory.
+ //
+ // If the heap is not yet configured (e.g. through the API), configure it.
+ // Configuration is based on the flags new-space-size (really the semispace
+ // size) and old-space-size if set or the initial values of semispace_size_
+ // and old_generation_size_ otherwise.
+ if (!configured_) {
+ if (!ConfigureHeapDefault()) return false;
+ }
+
+ base::CallOnce(&initialize_gc_once, &InitializeGCOnce);
+
+ MarkMapPointersAsEncoded(false);
+
+ // Set up memory allocator.
+ if (!isolate_->memory_allocator()->SetUp(MaxReserved(), MaxExecutableSize()))
+ return false;
+
+ // Set up new space.
+ if (!new_space_.SetUp(reserved_semispace_size_, max_semi_space_size_)) {
+ return false;
+ }
+ new_space_top_after_last_gc_ = new_space()->top();
+
+ // Initialize old pointer space.
+ old_pointer_space_ = new OldSpace(this, max_old_generation_size_,
+ OLD_POINTER_SPACE, NOT_EXECUTABLE);
+ if (old_pointer_space_ == NULL) return false;
+ if (!old_pointer_space_->SetUp()) return false;
+
+ // Initialize old data space.
+ old_data_space_ = new OldSpace(this, max_old_generation_size_, OLD_DATA_SPACE,
+ NOT_EXECUTABLE);
+ if (old_data_space_ == NULL) return false;
+ if (!old_data_space_->SetUp()) return false;
+
+ if (!isolate_->code_range()->SetUp(code_range_size_)) return false;
+
+ // Initialize the code space, set its maximum capacity to the old
+ // generation size. It needs executable memory.
+ code_space_ =
+ new OldSpace(this, max_old_generation_size_, CODE_SPACE, EXECUTABLE);
+ if (code_space_ == NULL) return false;
+ if (!code_space_->SetUp()) return false;
+
+ // Initialize map space.
+ map_space_ = new MapSpace(this, max_old_generation_size_, MAP_SPACE);
+ if (map_space_ == NULL) return false;
+ if (!map_space_->SetUp()) return false;
+
+ // Initialize simple cell space.
+ cell_space_ = new CellSpace(this, max_old_generation_size_, CELL_SPACE);
+ if (cell_space_ == NULL) return false;
+ if (!cell_space_->SetUp()) return false;
+
+ // Initialize global property cell space.
+ property_cell_space_ = new PropertyCellSpace(this, max_old_generation_size_,
+ PROPERTY_CELL_SPACE);
+ if (property_cell_space_ == NULL) return false;
+ if (!property_cell_space_->SetUp()) return false;
+
+ // The large object code space may contain code or data. We set the memory
+ // to be non-executable here for safety, but this means we need to enable it
+ // explicitly when allocating large code objects.
+ lo_space_ = new LargeObjectSpace(this, max_old_generation_size_, LO_SPACE);
+ if (lo_space_ == NULL) return false;
+ if (!lo_space_->SetUp()) return false;
+
+ // Set up the seed that is used to randomize the string hash function.
+ DCHECK(hash_seed() == 0);
+ if (FLAG_randomize_hashes) {
+ if (FLAG_hash_seed == 0) {
+ int rnd = isolate()->random_number_generator()->NextInt();
+ set_hash_seed(Smi::FromInt(rnd & Name::kHashBitMask));
+ } else {
+ set_hash_seed(Smi::FromInt(FLAG_hash_seed));
+ }
+ }
+
+ LOG(isolate_, IntPtrTEvent("heap-capacity", Capacity()));
+ LOG(isolate_, IntPtrTEvent("heap-available", Available()));
+
+ store_buffer()->SetUp();
+
+ mark_compact_collector()->SetUp();
+
+ return true;
+}
+
+
+bool Heap::CreateHeapObjects() {
+ // Create initial maps.
+ if (!CreateInitialMaps()) return false;
+ CreateApiObjects();
+
+ // Create initial objects
+ CreateInitialObjects();
+ CHECK_EQ(0, gc_count_);
+
+ set_native_contexts_list(undefined_value());
+ set_array_buffers_list(undefined_value());
+ set_allocation_sites_list(undefined_value());
+ weak_object_to_code_table_ = undefined_value();
+ return true;
+}
+
+
+void Heap::SetStackLimits() {
+ DCHECK(isolate_ != NULL);
+ DCHECK(isolate_ == isolate());
+ // On 64 bit machines, pointers are generally out of range of Smis. We write
+ // something that looks like an out of range Smi to the GC.
+
+ // Set up the special root array entries containing the stack limits.
+ // These are actually addresses, but the tag makes the GC ignore it.
+ roots_[kStackLimitRootIndex] = reinterpret_cast<Object*>(
+ (isolate_->stack_guard()->jslimit() & ~kSmiTagMask) | kSmiTag);
+ roots_[kRealStackLimitRootIndex] = reinterpret_cast<Object*>(
+ (isolate_->stack_guard()->real_jslimit() & ~kSmiTagMask) | kSmiTag);
+}
+
+
+void Heap::TearDown() {
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+#endif
+
+ UpdateMaximumCommitted();
+
+ if (FLAG_print_cumulative_gc_stat) {
+ PrintF("\n");
+ PrintF("gc_count=%d ", gc_count_);
+ PrintF("mark_sweep_count=%d ", ms_count_);
+ PrintF("max_gc_pause=%.1f ", get_max_gc_pause());
+ PrintF("total_gc_time=%.1f ", total_gc_time_ms_);
+ PrintF("min_in_mutator=%.1f ", get_min_in_mutator());
+ PrintF("max_alive_after_gc=%" V8_PTR_PREFIX "d ", get_max_alive_after_gc());
+ PrintF("total_marking_time=%.1f ", tracer_.cumulative_sweeping_duration());
+ PrintF("total_sweeping_time=%.1f ", tracer_.cumulative_sweeping_duration());
+ PrintF("\n\n");
+ }
+
+ if (FLAG_print_max_heap_committed) {
+ PrintF("\n");
+ PrintF("maximum_committed_by_heap=%" V8_PTR_PREFIX "d ",
+ MaximumCommittedMemory());
+ PrintF("maximum_committed_by_new_space=%" V8_PTR_PREFIX "d ",
+ new_space_.MaximumCommittedMemory());
+ PrintF("maximum_committed_by_old_pointer_space=%" V8_PTR_PREFIX "d ",
+ old_data_space_->MaximumCommittedMemory());
+ PrintF("maximum_committed_by_old_data_space=%" V8_PTR_PREFIX "d ",
+ old_pointer_space_->MaximumCommittedMemory());
+ PrintF("maximum_committed_by_old_data_space=%" V8_PTR_PREFIX "d ",
+ old_pointer_space_->MaximumCommittedMemory());
+ PrintF("maximum_committed_by_code_space=%" V8_PTR_PREFIX "d ",
+ code_space_->MaximumCommittedMemory());
+ PrintF("maximum_committed_by_map_space=%" V8_PTR_PREFIX "d ",
+ map_space_->MaximumCommittedMemory());
+ PrintF("maximum_committed_by_cell_space=%" V8_PTR_PREFIX "d ",
+ cell_space_->MaximumCommittedMemory());
+ PrintF("maximum_committed_by_property_space=%" V8_PTR_PREFIX "d ",
+ property_cell_space_->MaximumCommittedMemory());
+ PrintF("maximum_committed_by_lo_space=%" V8_PTR_PREFIX "d ",
+ lo_space_->MaximumCommittedMemory());
+ PrintF("\n\n");
+ }
+
+ if (FLAG_verify_predictable) {
+ PrintAlloctionsHash();
+ }
+
+ TearDownArrayBuffers();
+
+ isolate_->global_handles()->TearDown();
+
+ external_string_table_.TearDown();
+
+ mark_compact_collector()->TearDown();
+
+ new_space_.TearDown();
+
+ if (old_pointer_space_ != NULL) {
+ old_pointer_space_->TearDown();
+ delete old_pointer_space_;
+ old_pointer_space_ = NULL;
+ }
+
+ if (old_data_space_ != NULL) {
+ old_data_space_->TearDown();
+ delete old_data_space_;
+ old_data_space_ = NULL;
+ }
+
+ if (code_space_ != NULL) {
+ code_space_->TearDown();
+ delete code_space_;
+ code_space_ = NULL;
+ }
+
+ if (map_space_ != NULL) {
+ map_space_->TearDown();
+ delete map_space_;
+ map_space_ = NULL;
+ }
+
+ if (cell_space_ != NULL) {
+ cell_space_->TearDown();
+ delete cell_space_;
+ cell_space_ = NULL;
+ }
+
+ if (property_cell_space_ != NULL) {
+ property_cell_space_->TearDown();
+ delete property_cell_space_;
+ property_cell_space_ = NULL;
+ }
+
+ if (lo_space_ != NULL) {
+ lo_space_->TearDown();
+ delete lo_space_;
+ lo_space_ = NULL;
+ }
+
+ store_buffer()->TearDown();
+ incremental_marking()->TearDown();
+
+ isolate_->memory_allocator()->TearDown();
+}
+
+
+void Heap::AddGCPrologueCallback(v8::Isolate::GCPrologueCallback callback,
+ GCType gc_type, bool pass_isolate) {
+ DCHECK(callback != NULL);
+ GCPrologueCallbackPair pair(callback, gc_type, pass_isolate);
+ DCHECK(!gc_prologue_callbacks_.Contains(pair));
+ return gc_prologue_callbacks_.Add(pair);
+}
+
+
+void Heap::RemoveGCPrologueCallback(v8::Isolate::GCPrologueCallback callback) {
+ DCHECK(callback != NULL);
+ for (int i = 0; i < gc_prologue_callbacks_.length(); ++i) {
+ if (gc_prologue_callbacks_[i].callback == callback) {
+ gc_prologue_callbacks_.Remove(i);
+ return;
+ }
+ }
+ UNREACHABLE();
+}
+
+
+void Heap::AddGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback,
+ GCType gc_type, bool pass_isolate) {
+ DCHECK(callback != NULL);
+ GCEpilogueCallbackPair pair(callback, gc_type, pass_isolate);
+ DCHECK(!gc_epilogue_callbacks_.Contains(pair));
+ return gc_epilogue_callbacks_.Add(pair);
+}
+
+
+void Heap::RemoveGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback) {
+ DCHECK(callback != NULL);
+ for (int i = 0; i < gc_epilogue_callbacks_.length(); ++i) {
+ if (gc_epilogue_callbacks_[i].callback == callback) {
+ gc_epilogue_callbacks_.Remove(i);
+ return;
+ }
+ }
+ UNREACHABLE();
+}
+
+
+// TODO(ishell): Find a better place for this.
+void Heap::AddWeakObjectToCodeDependency(Handle<Object> obj,
+ Handle<DependentCode> dep) {
+ DCHECK(!InNewSpace(*obj));
+ DCHECK(!InNewSpace(*dep));
+ // This handle scope keeps the table handle local to this function, which
+ // allows us to safely skip write barriers in table update operations.
+ HandleScope scope(isolate());
+ Handle<WeakHashTable> table(WeakHashTable::cast(weak_object_to_code_table_),
+ isolate());
+ table = WeakHashTable::Put(table, obj, dep);
+
+ if (ShouldZapGarbage() && weak_object_to_code_table_ != *table) {
+ WeakHashTable::cast(weak_object_to_code_table_)->Zap(the_hole_value());
+ }
+ set_weak_object_to_code_table(*table);
+ DCHECK_EQ(*dep, table->Lookup(obj));
+}
+
+
+DependentCode* Heap::LookupWeakObjectToCodeDependency(Handle<Object> obj) {
+ Object* dep = WeakHashTable::cast(weak_object_to_code_table_)->Lookup(obj);
+ if (dep->IsDependentCode()) return DependentCode::cast(dep);
+ return DependentCode::cast(empty_fixed_array());
+}
+
+
+void Heap::EnsureWeakObjectToCodeTable() {
+ if (!weak_object_to_code_table()->IsHashTable()) {
+ set_weak_object_to_code_table(
+ *WeakHashTable::New(isolate(), 16, USE_DEFAULT_MINIMUM_CAPACITY,
+ TENURED));
+ }
+}
+
+
+void Heap::FatalProcessOutOfMemory(const char* location, bool take_snapshot) {
+ v8::internal::V8::FatalProcessOutOfMemory(location, take_snapshot);
+}
+
+#ifdef DEBUG
+
+class PrintHandleVisitor : public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++)
+ PrintF(" handle %p to %p\n", reinterpret_cast<void*>(p),
+ reinterpret_cast<void*>(*p));
+ }
+};
+
+
+void Heap::PrintHandles() {
+ PrintF("Handles:\n");
+ PrintHandleVisitor v;
+ isolate_->handle_scope_implementer()->Iterate(&v);
+}
+
+#endif
+
+
+Space* AllSpaces::next() {
+ switch (counter_++) {
+ case NEW_SPACE:
+ return heap_->new_space();
+ case OLD_POINTER_SPACE:
+ return heap_->old_pointer_space();
+ case OLD_DATA_SPACE:
+ return heap_->old_data_space();
+ case CODE_SPACE:
+ return heap_->code_space();
+ case MAP_SPACE:
+ return heap_->map_space();
+ case CELL_SPACE:
+ return heap_->cell_space();
+ case PROPERTY_CELL_SPACE:
+ return heap_->property_cell_space();
+ case LO_SPACE:
+ return heap_->lo_space();
+ default:
+ return NULL;
+ }
+}
+
+
+PagedSpace* PagedSpaces::next() {
+ switch (counter_++) {
+ case OLD_POINTER_SPACE:
+ return heap_->old_pointer_space();
+ case OLD_DATA_SPACE:
+ return heap_->old_data_space();
+ case CODE_SPACE:
+ return heap_->code_space();
+ case MAP_SPACE:
+ return heap_->map_space();
+ case CELL_SPACE:
+ return heap_->cell_space();
+ case PROPERTY_CELL_SPACE:
+ return heap_->property_cell_space();
+ default:
+ return NULL;
+ }
+}
+
+
+OldSpace* OldSpaces::next() {
+ switch (counter_++) {
+ case OLD_POINTER_SPACE:
+ return heap_->old_pointer_space();
+ case OLD_DATA_SPACE:
+ return heap_->old_data_space();
+ case CODE_SPACE:
+ return heap_->code_space();
+ default:
+ return NULL;
+ }
+}
+
+
+SpaceIterator::SpaceIterator(Heap* heap)
+ : heap_(heap),
+ current_space_(FIRST_SPACE),
+ iterator_(NULL),
+ size_func_(NULL) {}
+
+
+SpaceIterator::SpaceIterator(Heap* heap, HeapObjectCallback size_func)
+ : heap_(heap),
+ current_space_(FIRST_SPACE),
+ iterator_(NULL),
+ size_func_(size_func) {}
+
+
+SpaceIterator::~SpaceIterator() {
+ // Delete active iterator if any.
+ delete iterator_;
+}
+
+
+bool SpaceIterator::has_next() {
+ // Iterate until no more spaces.
+ return current_space_ != LAST_SPACE;
+}
+
+
+ObjectIterator* SpaceIterator::next() {
+ if (iterator_ != NULL) {
+ delete iterator_;
+ iterator_ = NULL;
+ // Move to the next space
+ current_space_++;
+ if (current_space_ > LAST_SPACE) {
+ return NULL;
+ }
+ }
+
+ // Return iterator for the new current space.
+ return CreateIterator();
+}
+
+
+// Create an iterator for the space to iterate.
+ObjectIterator* SpaceIterator::CreateIterator() {
+ DCHECK(iterator_ == NULL);
+
+ switch (current_space_) {
+ case NEW_SPACE:
+ iterator_ = new SemiSpaceIterator(heap_->new_space(), size_func_);
+ break;
+ case OLD_POINTER_SPACE:
+ iterator_ =
+ new HeapObjectIterator(heap_->old_pointer_space(), size_func_);
+ break;
+ case OLD_DATA_SPACE:
+ iterator_ = new HeapObjectIterator(heap_->old_data_space(), size_func_);
+ break;
+ case CODE_SPACE:
+ iterator_ = new HeapObjectIterator(heap_->code_space(), size_func_);
+ break;
+ case MAP_SPACE:
+ iterator_ = new HeapObjectIterator(heap_->map_space(), size_func_);
+ break;
+ case CELL_SPACE:
+ iterator_ = new HeapObjectIterator(heap_->cell_space(), size_func_);
+ break;
+ case PROPERTY_CELL_SPACE:
+ iterator_ =
+ new HeapObjectIterator(heap_->property_cell_space(), size_func_);
+ break;
+ case LO_SPACE:
+ iterator_ = new LargeObjectIterator(heap_->lo_space(), size_func_);
+ break;
+ }
+
+ // Return the newly allocated iterator;
+ DCHECK(iterator_ != NULL);
+ return iterator_;
+}
+
+
+class HeapObjectsFilter {
+ public:
+ virtual ~HeapObjectsFilter() {}
+ virtual bool SkipObject(HeapObject* object) = 0;
+};
+
+
+class UnreachableObjectsFilter : public HeapObjectsFilter {
+ public:
+ explicit UnreachableObjectsFilter(Heap* heap) : heap_(heap) {
+ MarkReachableObjects();
+ }
+
+ ~UnreachableObjectsFilter() {
+ heap_->mark_compact_collector()->ClearMarkbits();
+ }
+
+ bool SkipObject(HeapObject* object) {
+ MarkBit mark_bit = Marking::MarkBitFrom(object);
+ return !mark_bit.Get();
+ }
+
+ private:
+ class MarkingVisitor : public ObjectVisitor {
+ public:
+ MarkingVisitor() : marking_stack_(10) {}
+
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++) {
+ if (!(*p)->IsHeapObject()) continue;
+ HeapObject* obj = HeapObject::cast(*p);
+ MarkBit mark_bit = Marking::MarkBitFrom(obj);
+ if (!mark_bit.Get()) {
+ mark_bit.Set();
+ marking_stack_.Add(obj);
+ }
+ }
+ }
+
+ void TransitiveClosure() {
+ while (!marking_stack_.is_empty()) {
+ HeapObject* obj = marking_stack_.RemoveLast();
+ obj->Iterate(this);
+ }
+ }
+
+ private:
+ List<HeapObject*> marking_stack_;
+ };
+
+ void MarkReachableObjects() {
+ MarkingVisitor visitor;
+ heap_->IterateRoots(&visitor, VISIT_ALL);
+ visitor.TransitiveClosure();
+ }
+
+ Heap* heap_;
+ DisallowHeapAllocation no_allocation_;
+};
+
+
+HeapIterator::HeapIterator(Heap* heap)
+ : make_heap_iterable_helper_(heap),
+ no_heap_allocation_(),
+ heap_(heap),
+ filtering_(HeapIterator::kNoFiltering),
+ filter_(NULL) {
+ Init();
+}
+
+
+HeapIterator::HeapIterator(Heap* heap,
+ HeapIterator::HeapObjectsFiltering filtering)
+ : make_heap_iterable_helper_(heap),
+ no_heap_allocation_(),
+ heap_(heap),
+ filtering_(filtering),
+ filter_(NULL) {
+ Init();
+}
+
+
+HeapIterator::~HeapIterator() { Shutdown(); }
+
+
+void HeapIterator::Init() {
+ // Start the iteration.
+ space_iterator_ = new SpaceIterator(heap_);
+ switch (filtering_) {
+ case kFilterUnreachable:
+ filter_ = new UnreachableObjectsFilter(heap_);
+ break;
+ default:
+ break;
+ }
+ object_iterator_ = space_iterator_->next();
+}
+
+
+void HeapIterator::Shutdown() {
+#ifdef DEBUG
+ // Assert that in filtering mode we have iterated through all
+ // objects. Otherwise, heap will be left in an inconsistent state.
+ if (filtering_ != kNoFiltering) {
+ DCHECK(object_iterator_ == NULL);
+ }
+#endif
+ // Make sure the last iterator is deallocated.
+ delete space_iterator_;
+ space_iterator_ = NULL;
+ object_iterator_ = NULL;
+ delete filter_;
+ filter_ = NULL;
+}
+
+
+HeapObject* HeapIterator::next() {
+ if (filter_ == NULL) return NextObject();
+
+ HeapObject* obj = NextObject();
+ while (obj != NULL && filter_->SkipObject(obj)) obj = NextObject();
+ return obj;
+}
+
+
+HeapObject* HeapIterator::NextObject() {
+ // No iterator means we are done.
+ if (object_iterator_ == NULL) return NULL;
+
+ if (HeapObject* obj = object_iterator_->next_object()) {
+ // If the current iterator has more objects we are fine.
+ return obj;
+ } else {
+ // Go though the spaces looking for one that has objects.
+ while (space_iterator_->has_next()) {
+ object_iterator_ = space_iterator_->next();
+ if (HeapObject* obj = object_iterator_->next_object()) {
+ return obj;
+ }
+ }
+ }
+ // Done with the last space.
+ object_iterator_ = NULL;
+ return NULL;
+}
+
+
+void HeapIterator::reset() {
+ // Restart the iterator.
+ Shutdown();
+ Init();
+}
+
+
+#ifdef DEBUG
+
+Object* const PathTracer::kAnyGlobalObject = NULL;
+
+class PathTracer::MarkVisitor : public ObjectVisitor {
+ public:
+ explicit MarkVisitor(PathTracer* tracer) : tracer_(tracer) {}
+ void VisitPointers(Object** start, Object** end) {
+ // Scan all HeapObject pointers in [start, end)
+ for (Object** p = start; !tracer_->found() && (p < end); p++) {
+ if ((*p)->IsHeapObject()) tracer_->MarkRecursively(p, this);
+ }
+ }
+
+ private:
+ PathTracer* tracer_;
+};
+
+
+class PathTracer::UnmarkVisitor : public ObjectVisitor {
+ public:
+ explicit UnmarkVisitor(PathTracer* tracer) : tracer_(tracer) {}
+ void VisitPointers(Object** start, Object** end) {
+ // Scan all HeapObject pointers in [start, end)
+ for (Object** p = start; p < end; p++) {
+ if ((*p)->IsHeapObject()) tracer_->UnmarkRecursively(p, this);
+ }
+ }
+
+ private:
+ PathTracer* tracer_;
+};
+
+
+void PathTracer::VisitPointers(Object** start, Object** end) {
+ bool done = ((what_to_find_ == FIND_FIRST) && found_target_);
+ // Visit all HeapObject pointers in [start, end)
+ for (Object** p = start; !done && (p < end); p++) {
+ if ((*p)->IsHeapObject()) {
+ TracePathFrom(p);
+ done = ((what_to_find_ == FIND_FIRST) && found_target_);
+ }
+ }
+}
+
+
+void PathTracer::Reset() {
+ found_target_ = false;
+ object_stack_.Clear();
+}
+
+
+void PathTracer::TracePathFrom(Object** root) {
+ DCHECK((search_target_ == kAnyGlobalObject) ||
+ search_target_->IsHeapObject());
+ found_target_in_trace_ = false;
+ Reset();
+
+ MarkVisitor mark_visitor(this);
+ MarkRecursively(root, &mark_visitor);
+
+ UnmarkVisitor unmark_visitor(this);
+ UnmarkRecursively(root, &unmark_visitor);
+
+ ProcessResults();
+}
+
+
+static bool SafeIsNativeContext(HeapObject* obj) {
+ return obj->map() == obj->GetHeap()->raw_unchecked_native_context_map();
+}
+
+
+void PathTracer::MarkRecursively(Object** p, MarkVisitor* mark_visitor) {
+ if (!(*p)->IsHeapObject()) return;
+
+ HeapObject* obj = HeapObject::cast(*p);
+
+ MapWord map_word = obj->map_word();
+ if (!map_word.ToMap()->IsHeapObject()) return; // visited before
+
+ if (found_target_in_trace_) return; // stop if target found
+ object_stack_.Add(obj);
+ if (((search_target_ == kAnyGlobalObject) && obj->IsJSGlobalObject()) ||
+ (obj == search_target_)) {
+ found_target_in_trace_ = true;
+ found_target_ = true;
+ return;
+ }
+
+ bool is_native_context = SafeIsNativeContext(obj);
+
+ // not visited yet
+ Map* map = Map::cast(map_word.ToMap());
+
+ MapWord marked_map_word =
+ MapWord::FromRawValue(obj->map_word().ToRawValue() + kMarkTag);
+ obj->set_map_word(marked_map_word);
+
+ // Scan the object body.
+ if (is_native_context && (visit_mode_ == VISIT_ONLY_STRONG)) {
+ // This is specialized to scan Context's properly.
+ Object** start =
+ reinterpret_cast<Object**>(obj->address() + Context::kHeaderSize);
+ Object** end =
+ reinterpret_cast<Object**>(obj->address() + Context::kHeaderSize +
+ Context::FIRST_WEAK_SLOT * kPointerSize);
+ mark_visitor->VisitPointers(start, end);
+ } else {
+ obj->IterateBody(map->instance_type(), obj->SizeFromMap(map), mark_visitor);
+ }
+
+ // Scan the map after the body because the body is a lot more interesting
+ // when doing leak detection.
+ MarkRecursively(reinterpret_cast<Object**>(&map), mark_visitor);
+
+ if (!found_target_in_trace_) { // don't pop if found the target
+ object_stack_.RemoveLast();
+ }
+}
+
+
+void PathTracer::UnmarkRecursively(Object** p, UnmarkVisitor* unmark_visitor) {
+ if (!(*p)->IsHeapObject()) return;
+
+ HeapObject* obj = HeapObject::cast(*p);
+
+ MapWord map_word = obj->map_word();
+ if (map_word.ToMap()->IsHeapObject()) return; // unmarked already
+
+ MapWord unmarked_map_word =
+ MapWord::FromRawValue(map_word.ToRawValue() - kMarkTag);
+ obj->set_map_word(unmarked_map_word);
+
+ Map* map = Map::cast(unmarked_map_word.ToMap());
+
+ UnmarkRecursively(reinterpret_cast<Object**>(&map), unmark_visitor);
+
+ obj->IterateBody(map->instance_type(), obj->SizeFromMap(map), unmark_visitor);
+}
+
+
+void PathTracer::ProcessResults() {
+ if (found_target_) {
+ OFStream os(stdout);
+ os << "=====================================\n"
+ << "==== Path to object ====\n"
+ << "=====================================\n\n";
+
+ DCHECK(!object_stack_.is_empty());
+ for (int i = 0; i < object_stack_.length(); i++) {
+ if (i > 0) os << "\n |\n |\n V\n\n";
+ object_stack_[i]->Print(os);
+ }
+ os << "=====================================\n";
+ }
+}
+
+
+// Triggers a depth-first traversal of reachable objects from one
+// given root object and finds a path to a specific heap object and
+// prints it.
+void Heap::TracePathToObjectFrom(Object* target, Object* root) {
+ PathTracer tracer(target, PathTracer::FIND_ALL, VISIT_ALL);
+ tracer.VisitPointer(&root);
+}
+
+
+// Triggers a depth-first traversal of reachable objects from roots
+// and finds a path to a specific heap object and prints it.
+void Heap::TracePathToObject(Object* target) {
+ PathTracer tracer(target, PathTracer::FIND_ALL, VISIT_ALL);
+ IterateRoots(&tracer, VISIT_ONLY_STRONG);
+}
+
+
+// Triggers a depth-first traversal of reachable objects from roots
+// and finds a path to any global object and prints it. Useful for
+// determining the source for leaks of global objects.
+void Heap::TracePathToGlobal() {
+ PathTracer tracer(PathTracer::kAnyGlobalObject, PathTracer::FIND_ALL,
+ VISIT_ALL);
+ IterateRoots(&tracer, VISIT_ONLY_STRONG);
+}
+#endif
+
+
+void Heap::UpdateCumulativeGCStatistics(double duration,
+ double spent_in_mutator,
+ double marking_time) {
+ if (FLAG_print_cumulative_gc_stat) {
+ total_gc_time_ms_ += duration;
+ max_gc_pause_ = Max(max_gc_pause_, duration);
+ max_alive_after_gc_ = Max(max_alive_after_gc_, SizeOfObjects());
+ min_in_mutator_ = Min(min_in_mutator_, spent_in_mutator);
+ } else if (FLAG_trace_gc_verbose) {
+ total_gc_time_ms_ += duration;
+ }
+
+ marking_time_ += marking_time;
+}
+
+
+int KeyedLookupCache::Hash(Handle<Map> map, Handle<Name> name) {
+ DisallowHeapAllocation no_gc;
+ // Uses only lower 32 bits if pointers are larger.
+ uintptr_t addr_hash =
+ static_cast<uint32_t>(reinterpret_cast<uintptr_t>(*map)) >> kMapHashShift;
+ return static_cast<uint32_t>((addr_hash ^ name->Hash()) & kCapacityMask);
+}
+
+
+int KeyedLookupCache::Lookup(Handle<Map> map, Handle<Name> name) {
+ DisallowHeapAllocation no_gc;
+ int index = (Hash(map, name) & kHashMask);
+ for (int i = 0; i < kEntriesPerBucket; i++) {
+ Key& key = keys_[index + i];
+ if ((key.map == *map) && key.name->Equals(*name)) {
+ return field_offsets_[index + i];
+ }
+ }
+ return kNotFound;
+}
+
+
+void KeyedLookupCache::Update(Handle<Map> map, Handle<Name> name,
+ int field_offset) {
+ DisallowHeapAllocation no_gc;
+ if (!name->IsUniqueName()) {
+ if (!StringTable::InternalizeStringIfExists(
+ name->GetIsolate(), Handle<String>::cast(name)).ToHandle(&name)) {
+ return;
+ }
+ }
+ // This cache is cleared only between mark compact passes, so we expect the
+ // cache to only contain old space names.
+ DCHECK(!map->GetIsolate()->heap()->InNewSpace(*name));
+
+ int index = (Hash(map, name) & kHashMask);
+ // After a GC there will be free slots, so we use them in order (this may
+ // help to get the most frequently used one in position 0).
+ for (int i = 0; i < kEntriesPerBucket; i++) {
+ Key& key = keys_[index];
+ Object* free_entry_indicator = NULL;
+ if (key.map == free_entry_indicator) {
+ key.map = *map;
+ key.name = *name;
+ field_offsets_[index + i] = field_offset;
+ return;
+ }
+ }
+ // No free entry found in this bucket, so we move them all down one and
+ // put the new entry at position zero.
+ for (int i = kEntriesPerBucket - 1; i > 0; i--) {
+ Key& key = keys_[index + i];
+ Key& key2 = keys_[index + i - 1];
+ key = key2;
+ field_offsets_[index + i] = field_offsets_[index + i - 1];
+ }
+
+ // Write the new first entry.
+ Key& key = keys_[index];
+ key.map = *map;
+ key.name = *name;
+ field_offsets_[index] = field_offset;
+}
+
+
+void KeyedLookupCache::Clear() {
+ for (int index = 0; index < kLength; index++) keys_[index].map = NULL;
+}
+
+
+void DescriptorLookupCache::Clear() {
+ for (int index = 0; index < kLength; index++) keys_[index].source = NULL;
+}
+
+
+void ExternalStringTable::CleanUp() {
+ int last = 0;
+ for (int i = 0; i < new_space_strings_.length(); ++i) {
+ if (new_space_strings_[i] == heap_->the_hole_value()) {
+ continue;
+ }
+ DCHECK(new_space_strings_[i]->IsExternalString());
+ if (heap_->InNewSpace(new_space_strings_[i])) {
+ new_space_strings_[last++] = new_space_strings_[i];
+ } else {
+ old_space_strings_.Add(new_space_strings_[i]);
+ }
+ }
+ new_space_strings_.Rewind(last);
+ new_space_strings_.Trim();
+
+ last = 0;
+ for (int i = 0; i < old_space_strings_.length(); ++i) {
+ if (old_space_strings_[i] == heap_->the_hole_value()) {
+ continue;
+ }
+ DCHECK(old_space_strings_[i]->IsExternalString());
+ DCHECK(!heap_->InNewSpace(old_space_strings_[i]));
+ old_space_strings_[last++] = old_space_strings_[i];
+ }
+ old_space_strings_.Rewind(last);
+ old_space_strings_.Trim();
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+#endif
+}
+
+
+void ExternalStringTable::TearDown() {
+ for (int i = 0; i < new_space_strings_.length(); ++i) {
+ heap_->FinalizeExternalString(ExternalString::cast(new_space_strings_[i]));
+ }
+ new_space_strings_.Free();
+ for (int i = 0; i < old_space_strings_.length(); ++i) {
+ heap_->FinalizeExternalString(ExternalString::cast(old_space_strings_[i]));
+ }
+ old_space_strings_.Free();
+}
+
+
+void Heap::QueueMemoryChunkForFree(MemoryChunk* chunk) {
+ chunk->set_next_chunk(chunks_queued_for_free_);
+ chunks_queued_for_free_ = chunk;
+}
+
+
+void Heap::FreeQueuedChunks() {
+ if (chunks_queued_for_free_ == NULL) return;
+ MemoryChunk* next;
+ MemoryChunk* chunk;
+ for (chunk = chunks_queued_for_free_; chunk != NULL; chunk = next) {
+ next = chunk->next_chunk();
+ chunk->SetFlag(MemoryChunk::ABOUT_TO_BE_FREED);
+
+ if (chunk->owner()->identity() == LO_SPACE) {
+ // StoreBuffer::Filter relies on MemoryChunk::FromAnyPointerAddress.
+ // If FromAnyPointerAddress encounters a slot that belongs to a large
+ // chunk queued for deletion it will fail to find the chunk because
+ // it try to perform a search in the list of pages owned by of the large
+ // object space and queued chunks were detached from that list.
+ // To work around this we split large chunk into normal kPageSize aligned
+ // pieces and initialize size, owner and flags field of every piece.
+ // If FromAnyPointerAddress encounters a slot that belongs to one of
+ // these smaller pieces it will treat it as a slot on a normal Page.
+ Address chunk_end = chunk->address() + chunk->size();
+ MemoryChunk* inner =
+ MemoryChunk::FromAddress(chunk->address() + Page::kPageSize);
+ MemoryChunk* inner_last = MemoryChunk::FromAddress(chunk_end - 1);
+ while (inner <= inner_last) {
+ // Size of a large chunk is always a multiple of
+ // OS::AllocateAlignment() so there is always
+ // enough space for a fake MemoryChunk header.
+ Address area_end = Min(inner->address() + Page::kPageSize, chunk_end);
+ // Guard against overflow.
+ if (area_end < inner->address()) area_end = chunk_end;
+ inner->SetArea(inner->address(), area_end);
+ inner->set_size(Page::kPageSize);
+ inner->set_owner(lo_space());
+ inner->SetFlag(MemoryChunk::ABOUT_TO_BE_FREED);
+ inner = MemoryChunk::FromAddress(inner->address() + Page::kPageSize);
+ }
+ }
+ }
+ isolate_->heap()->store_buffer()->Compact();
+ isolate_->heap()->store_buffer()->Filter(MemoryChunk::ABOUT_TO_BE_FREED);
+ for (chunk = chunks_queued_for_free_; chunk != NULL; chunk = next) {
+ next = chunk->next_chunk();
+ isolate_->memory_allocator()->Free(chunk);
+ }
+ chunks_queued_for_free_ = NULL;
+}
+
+
+void Heap::RememberUnmappedPage(Address page, bool compacted) {
+ uintptr_t p = reinterpret_cast<uintptr_t>(page);
+ // Tag the page pointer to make it findable in the dump file.
+ if (compacted) {
+ p ^= 0xc1ead & (Page::kPageSize - 1); // Cleared.
+ } else {
+ p ^= 0x1d1ed & (Page::kPageSize - 1); // I died.
+ }
+ remembered_unmapped_pages_[remembered_unmapped_pages_index_] =
+ reinterpret_cast<Address>(p);
+ remembered_unmapped_pages_index_++;
+ remembered_unmapped_pages_index_ %= kRememberedUnmappedPages;
+}
+
+
+void Heap::ClearObjectStats(bool clear_last_time_stats) {
+ memset(object_counts_, 0, sizeof(object_counts_));
+ memset(object_sizes_, 0, sizeof(object_sizes_));
+ if (clear_last_time_stats) {
+ memset(object_counts_last_time_, 0, sizeof(object_counts_last_time_));
+ memset(object_sizes_last_time_, 0, sizeof(object_sizes_last_time_));
+ }
+}
+
+
+static base::LazyMutex checkpoint_object_stats_mutex = LAZY_MUTEX_INITIALIZER;
+
+
+void Heap::CheckpointObjectStats() {
+ base::LockGuard<base::Mutex> lock_guard(
+ checkpoint_object_stats_mutex.Pointer());
+ Counters* counters = isolate()->counters();
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name) \
+ counters->count_of_##name()->Increment( \
+ static_cast<int>(object_counts_[name])); \
+ counters->count_of_##name()->Decrement( \
+ static_cast<int>(object_counts_last_time_[name])); \
+ counters->size_of_##name()->Increment( \
+ static_cast<int>(object_sizes_[name])); \
+ counters->size_of_##name()->Decrement( \
+ static_cast<int>(object_sizes_last_time_[name]));
+ INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+ int index;
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name) \
+ index = FIRST_CODE_KIND_SUB_TYPE + Code::name; \
+ counters->count_of_CODE_TYPE_##name()->Increment( \
+ static_cast<int>(object_counts_[index])); \
+ counters->count_of_CODE_TYPE_##name()->Decrement( \
+ static_cast<int>(object_counts_last_time_[index])); \
+ counters->size_of_CODE_TYPE_##name()->Increment( \
+ static_cast<int>(object_sizes_[index])); \
+ counters->size_of_CODE_TYPE_##name()->Decrement( \
+ static_cast<int>(object_sizes_last_time_[index]));
+ CODE_KIND_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name) \
+ index = FIRST_FIXED_ARRAY_SUB_TYPE + name; \
+ counters->count_of_FIXED_ARRAY_##name()->Increment( \
+ static_cast<int>(object_counts_[index])); \
+ counters->count_of_FIXED_ARRAY_##name()->Decrement( \
+ static_cast<int>(object_counts_last_time_[index])); \
+ counters->size_of_FIXED_ARRAY_##name()->Increment( \
+ static_cast<int>(object_sizes_[index])); \
+ counters->size_of_FIXED_ARRAY_##name()->Decrement( \
+ static_cast<int>(object_sizes_last_time_[index]));
+ FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+#define ADJUST_LAST_TIME_OBJECT_COUNT(name) \
+ index = \
+ FIRST_CODE_AGE_SUB_TYPE + Code::k##name##CodeAge - Code::kFirstCodeAge; \
+ counters->count_of_CODE_AGE_##name()->Increment( \
+ static_cast<int>(object_counts_[index])); \
+ counters->count_of_CODE_AGE_##name()->Decrement( \
+ static_cast<int>(object_counts_last_time_[index])); \
+ counters->size_of_CODE_AGE_##name()->Increment( \
+ static_cast<int>(object_sizes_[index])); \
+ counters->size_of_CODE_AGE_##name()->Decrement( \
+ static_cast<int>(object_sizes_last_time_[index]));
+ CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
+#undef ADJUST_LAST_TIME_OBJECT_COUNT
+
+ MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
+ MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
+ ClearObjectStats();
+}
+}
+} // namespace v8::internal
diff --git a/src/heap/heap.gyp b/src/heap/heap.gyp
new file mode 100644
index 0000000..2970eb8
--- /dev/null
+++ b/src/heap/heap.gyp
@@ -0,0 +1,52 @@
+# Copyright 2014 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+ 'variables': {
+ 'v8_code': 1,
+ },
+ 'includes': ['../../build/toolchain.gypi', '../../build/features.gypi'],
+ 'targets': [
+ {
+ 'target_name': 'heap-unittests',
+ 'type': 'executable',
+ 'dependencies': [
+ '../../testing/gtest.gyp:gtest',
+ '../../testing/gtest.gyp:gtest_main',
+ '../../tools/gyp/v8.gyp:v8_libplatform',
+ ],
+ 'include_dirs': [
+ '../..',
+ ],
+ 'sources': [ ### gcmole(all) ###
+ 'gc-idle-time-handler-unittest.cc',
+ ],
+ 'conditions': [
+ ['component=="shared_library"', {
+ # heap-unittests can't be built against a shared library, so we
+ # need to depend on the underlying static target in that case.
+ 'conditions': [
+ ['v8_use_snapshot=="true"', {
+ 'dependencies': ['../../tools/gyp/v8.gyp:v8_snapshot'],
+ },
+ {
+ 'dependencies': [
+ '../../tools/gyp/v8.gyp:v8_nosnapshot',
+ ],
+ }],
+ ],
+ }, {
+ 'dependencies': ['../../tools/gyp/v8.gyp:v8'],
+ }],
+ ['os_posix == 1', {
+ # TODO(svenpanne): This is a temporary work-around to fix the warnings
+ # that show up because we use -std=gnu++0x instead of -std=c++11.
+ 'cflags!': [
+ '-pedantic',
+ ],
+ }],
+ ],
+ },
+ ],
+}
diff --git a/src/heap/heap.h b/src/heap/heap.h
new file mode 100644
index 0000000..c9d0f31
--- /dev/null
+++ b/src/heap/heap.h
@@ -0,0 +1,2503 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_HEAP_H_
+#define V8_HEAP_HEAP_H_
+
+#include <cmath>
+
+#include "src/allocation.h"
+#include "src/assert-scope.h"
+#include "src/counters.h"
+#include "src/globals.h"
+#include "src/heap/gc-idle-time-handler.h"
+#include "src/heap/gc-tracer.h"
+#include "src/heap/incremental-marking.h"
+#include "src/heap/mark-compact.h"
+#include "src/heap/objects-visiting.h"
+#include "src/heap/spaces.h"
+#include "src/heap/store-buffer.h"
+#include "src/list.h"
+#include "src/splay-tree-inl.h"
+
+namespace v8 {
+namespace internal {
+
+// Defines all the roots in Heap.
+#define STRONG_ROOT_LIST(V) \
+ V(Map, byte_array_map, ByteArrayMap) \
+ V(Map, free_space_map, FreeSpaceMap) \
+ V(Map, one_pointer_filler_map, OnePointerFillerMap) \
+ V(Map, two_pointer_filler_map, TwoPointerFillerMap) \
+ /* Cluster the most popular ones in a few cache lines here at the top. */ \
+ V(Smi, store_buffer_top, StoreBufferTop) \
+ V(Oddball, undefined_value, UndefinedValue) \
+ V(Oddball, the_hole_value, TheHoleValue) \
+ V(Oddball, null_value, NullValue) \
+ V(Oddball, true_value, TrueValue) \
+ V(Oddball, false_value, FalseValue) \
+ V(Oddball, uninitialized_value, UninitializedValue) \
+ V(Oddball, exception, Exception) \
+ V(Map, cell_map, CellMap) \
+ V(Map, global_property_cell_map, GlobalPropertyCellMap) \
+ V(Map, shared_function_info_map, SharedFunctionInfoMap) \
+ V(Map, meta_map, MetaMap) \
+ V(Map, heap_number_map, HeapNumberMap) \
+ V(Map, mutable_heap_number_map, MutableHeapNumberMap) \
+ V(Map, native_context_map, NativeContextMap) \
+ V(Map, fixed_array_map, FixedArrayMap) \
+ V(Map, code_map, CodeMap) \
+ V(Map, scope_info_map, ScopeInfoMap) \
+ V(Map, fixed_cow_array_map, FixedCOWArrayMap) \
+ V(Map, fixed_double_array_map, FixedDoubleArrayMap) \
+ V(Map, constant_pool_array_map, ConstantPoolArrayMap) \
+ V(Oddball, no_interceptor_result_sentinel, NoInterceptorResultSentinel) \
+ V(Map, hash_table_map, HashTableMap) \
+ V(Map, ordered_hash_table_map, OrderedHashTableMap) \
+ V(FixedArray, empty_fixed_array, EmptyFixedArray) \
+ V(ByteArray, empty_byte_array, EmptyByteArray) \
+ V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray) \
+ V(ConstantPoolArray, empty_constant_pool_array, EmptyConstantPoolArray) \
+ V(Oddball, arguments_marker, ArgumentsMarker) \
+ /* The roots above this line should be boring from a GC point of view. */ \
+ /* This means they are never in new space and never on a page that is */ \
+ /* being compacted. */ \
+ V(FixedArray, number_string_cache, NumberStringCache) \
+ V(Object, instanceof_cache_function, InstanceofCacheFunction) \
+ V(Object, instanceof_cache_map, InstanceofCacheMap) \
+ V(Object, instanceof_cache_answer, InstanceofCacheAnswer) \
+ V(FixedArray, single_character_string_cache, SingleCharacterStringCache) \
+ V(FixedArray, string_split_cache, StringSplitCache) \
+ V(FixedArray, regexp_multiple_cache, RegExpMultipleCache) \
+ V(Oddball, termination_exception, TerminationException) \
+ V(Smi, hash_seed, HashSeed) \
+ V(Map, symbol_map, SymbolMap) \
+ V(Map, string_map, StringMap) \
+ V(Map, one_byte_string_map, OneByteStringMap) \
+ V(Map, cons_string_map, ConsStringMap) \
+ V(Map, cons_one_byte_string_map, ConsOneByteStringMap) \
+ V(Map, sliced_string_map, SlicedStringMap) \
+ V(Map, sliced_one_byte_string_map, SlicedOneByteStringMap) \
+ V(Map, external_string_map, ExternalStringMap) \
+ V(Map, external_string_with_one_byte_data_map, \
+ ExternalStringWithOneByteDataMap) \
+ V(Map, external_one_byte_string_map, ExternalOneByteStringMap) \
+ V(Map, short_external_string_map, ShortExternalStringMap) \
+ V(Map, short_external_string_with_one_byte_data_map, \
+ ShortExternalStringWithOneByteDataMap) \
+ V(Map, internalized_string_map, InternalizedStringMap) \
+ V(Map, one_byte_internalized_string_map, OneByteInternalizedStringMap) \
+ V(Map, external_internalized_string_map, ExternalInternalizedStringMap) \
+ V(Map, external_internalized_string_with_one_byte_data_map, \
+ ExternalInternalizedStringWithOneByteDataMap) \
+ V(Map, external_one_byte_internalized_string_map, \
+ ExternalOneByteInternalizedStringMap) \
+ V(Map, short_external_internalized_string_map, \
+ ShortExternalInternalizedStringMap) \
+ V(Map, short_external_internalized_string_with_one_byte_data_map, \
+ ShortExternalInternalizedStringWithOneByteDataMap) \
+ V(Map, short_external_one_byte_internalized_string_map, \
+ ShortExternalOneByteInternalizedStringMap) \
+ V(Map, short_external_one_byte_string_map, ShortExternalOneByteStringMap) \
+ V(Map, undetectable_string_map, UndetectableStringMap) \
+ V(Map, undetectable_one_byte_string_map, UndetectableOneByteStringMap) \
+ V(Map, external_int8_array_map, ExternalInt8ArrayMap) \
+ V(Map, external_uint8_array_map, ExternalUint8ArrayMap) \
+ V(Map, external_int16_array_map, ExternalInt16ArrayMap) \
+ V(Map, external_uint16_array_map, ExternalUint16ArrayMap) \
+ V(Map, external_int32_array_map, ExternalInt32ArrayMap) \
+ V(Map, external_uint32_array_map, ExternalUint32ArrayMap) \
+ V(Map, external_float32_array_map, ExternalFloat32ArrayMap) \
+ V(Map, external_float64_array_map, ExternalFloat64ArrayMap) \
+ V(Map, external_uint8_clamped_array_map, ExternalUint8ClampedArrayMap) \
+ V(ExternalArray, empty_external_int8_array, EmptyExternalInt8Array) \
+ V(ExternalArray, empty_external_uint8_array, EmptyExternalUint8Array) \
+ V(ExternalArray, empty_external_int16_array, EmptyExternalInt16Array) \
+ V(ExternalArray, empty_external_uint16_array, EmptyExternalUint16Array) \
+ V(ExternalArray, empty_external_int32_array, EmptyExternalInt32Array) \
+ V(ExternalArray, empty_external_uint32_array, EmptyExternalUint32Array) \
+ V(ExternalArray, empty_external_float32_array, EmptyExternalFloat32Array) \
+ V(ExternalArray, empty_external_float64_array, EmptyExternalFloat64Array) \
+ V(ExternalArray, empty_external_uint8_clamped_array, \
+ EmptyExternalUint8ClampedArray) \
+ V(Map, fixed_uint8_array_map, FixedUint8ArrayMap) \
+ V(Map, fixed_int8_array_map, FixedInt8ArrayMap) \
+ V(Map, fixed_uint16_array_map, FixedUint16ArrayMap) \
+ V(Map, fixed_int16_array_map, FixedInt16ArrayMap) \
+ V(Map, fixed_uint32_array_map, FixedUint32ArrayMap) \
+ V(Map, fixed_int32_array_map, FixedInt32ArrayMap) \
+ V(Map, fixed_float32_array_map, FixedFloat32ArrayMap) \
+ V(Map, fixed_float64_array_map, FixedFloat64ArrayMap) \
+ V(Map, fixed_uint8_clamped_array_map, FixedUint8ClampedArrayMap) \
+ V(FixedTypedArrayBase, empty_fixed_uint8_array, EmptyFixedUint8Array) \
+ V(FixedTypedArrayBase, empty_fixed_int8_array, EmptyFixedInt8Array) \
+ V(FixedTypedArrayBase, empty_fixed_uint16_array, EmptyFixedUint16Array) \
+ V(FixedTypedArrayBase, empty_fixed_int16_array, EmptyFixedInt16Array) \
+ V(FixedTypedArrayBase, empty_fixed_uint32_array, EmptyFixedUint32Array) \
+ V(FixedTypedArrayBase, empty_fixed_int32_array, EmptyFixedInt32Array) \
+ V(FixedTypedArrayBase, empty_fixed_float32_array, EmptyFixedFloat32Array) \
+ V(FixedTypedArrayBase, empty_fixed_float64_array, EmptyFixedFloat64Array) \
+ V(FixedTypedArrayBase, empty_fixed_uint8_clamped_array, \
+ EmptyFixedUint8ClampedArray) \
+ V(Map, sloppy_arguments_elements_map, SloppyArgumentsElementsMap) \
+ V(Map, function_context_map, FunctionContextMap) \
+ V(Map, catch_context_map, CatchContextMap) \
+ V(Map, with_context_map, WithContextMap) \
+ V(Map, block_context_map, BlockContextMap) \
+ V(Map, module_context_map, ModuleContextMap) \
+ V(Map, global_context_map, GlobalContextMap) \
+ V(Map, undefined_map, UndefinedMap) \
+ V(Map, the_hole_map, TheHoleMap) \
+ V(Map, null_map, NullMap) \
+ V(Map, boolean_map, BooleanMap) \
+ V(Map, uninitialized_map, UninitializedMap) \
+ V(Map, arguments_marker_map, ArgumentsMarkerMap) \
+ V(Map, no_interceptor_result_sentinel_map, NoInterceptorResultSentinelMap) \
+ V(Map, exception_map, ExceptionMap) \
+ V(Map, termination_exception_map, TerminationExceptionMap) \
+ V(Map, message_object_map, JSMessageObjectMap) \
+ V(Map, foreign_map, ForeignMap) \
+ V(HeapNumber, nan_value, NanValue) \
+ V(HeapNumber, infinity_value, InfinityValue) \
+ V(HeapNumber, minus_zero_value, MinusZeroValue) \
+ V(Map, neander_map, NeanderMap) \
+ V(JSObject, message_listeners, MessageListeners) \
+ V(UnseededNumberDictionary, code_stubs, CodeStubs) \
+ V(UnseededNumberDictionary, non_monomorphic_cache, NonMonomorphicCache) \
+ V(PolymorphicCodeCache, polymorphic_code_cache, PolymorphicCodeCache) \
+ V(Code, js_entry_code, JsEntryCode) \
+ V(Code, js_construct_entry_code, JsConstructEntryCode) \
+ V(FixedArray, natives_source_cache, NativesSourceCache) \
+ V(Script, empty_script, EmptyScript) \
+ V(NameDictionary, intrinsic_function_names, IntrinsicFunctionNames) \
+ V(Cell, undefined_cell, UndefineCell) \
+ V(JSObject, observation_state, ObservationState) \
+ V(Map, external_map, ExternalMap) \
+ V(Object, symbol_registry, SymbolRegistry) \
+ V(Symbol, frozen_symbol, FrozenSymbol) \
+ V(Symbol, nonexistent_symbol, NonExistentSymbol) \
+ V(Symbol, elements_transition_symbol, ElementsTransitionSymbol) \
+ V(SeededNumberDictionary, empty_slow_element_dictionary, \
+ EmptySlowElementDictionary) \
+ V(Symbol, observed_symbol, ObservedSymbol) \
+ V(Symbol, uninitialized_symbol, UninitializedSymbol) \
+ V(Symbol, megamorphic_symbol, MegamorphicSymbol) \
+ V(Symbol, premonomorphic_symbol, PremonomorphicSymbol) \
+ V(Symbol, generic_symbol, GenericSymbol) \
+ V(Symbol, stack_trace_symbol, StackTraceSymbol) \
+ V(Symbol, detailed_stack_trace_symbol, DetailedStackTraceSymbol) \
+ V(Symbol, normal_ic_symbol, NormalICSymbol) \
+ V(Symbol, home_object_symbol, HomeObjectSymbol) \
+ V(FixedArray, materialized_objects, MaterializedObjects) \
+ V(FixedArray, allocation_sites_scratchpad, AllocationSitesScratchpad) \
+ V(FixedArray, microtask_queue, MicrotaskQueue)
+
+// Entries in this list are limited to Smis and are not visited during GC.
+#define SMI_ROOT_LIST(V) \
+ V(Smi, stack_limit, StackLimit) \
+ V(Smi, real_stack_limit, RealStackLimit) \
+ V(Smi, last_script_id, LastScriptId) \
+ V(Smi, arguments_adaptor_deopt_pc_offset, ArgumentsAdaptorDeoptPCOffset) \
+ V(Smi, construct_stub_deopt_pc_offset, ConstructStubDeoptPCOffset) \
+ V(Smi, getter_stub_deopt_pc_offset, GetterStubDeoptPCOffset) \
+ V(Smi, setter_stub_deopt_pc_offset, SetterStubDeoptPCOffset)
+
+#define ROOT_LIST(V) \
+ STRONG_ROOT_LIST(V) \
+ SMI_ROOT_LIST(V) \
+ V(StringTable, string_table, StringTable)
+
+// Heap roots that are known to be immortal immovable, for which we can safely
+// skip write barriers.
+#define IMMORTAL_IMMOVABLE_ROOT_LIST(V) \
+ V(byte_array_map) \
+ V(free_space_map) \
+ V(one_pointer_filler_map) \
+ V(two_pointer_filler_map) \
+ V(undefined_value) \
+ V(the_hole_value) \
+ V(null_value) \
+ V(true_value) \
+ V(false_value) \
+ V(uninitialized_value) \
+ V(cell_map) \
+ V(global_property_cell_map) \
+ V(shared_function_info_map) \
+ V(meta_map) \
+ V(heap_number_map) \
+ V(mutable_heap_number_map) \
+ V(native_context_map) \
+ V(fixed_array_map) \
+ V(code_map) \
+ V(scope_info_map) \
+ V(fixed_cow_array_map) \
+ V(fixed_double_array_map) \
+ V(constant_pool_array_map) \
+ V(no_interceptor_result_sentinel) \
+ V(hash_table_map) \
+ V(ordered_hash_table_map) \
+ V(empty_fixed_array) \
+ V(empty_byte_array) \
+ V(empty_descriptor_array) \
+ V(empty_constant_pool_array) \
+ V(arguments_marker) \
+ V(symbol_map) \
+ V(sloppy_arguments_elements_map) \
+ V(function_context_map) \
+ V(catch_context_map) \
+ V(with_context_map) \
+ V(block_context_map) \
+ V(module_context_map) \
+ V(global_context_map) \
+ V(undefined_map) \
+ V(the_hole_map) \
+ V(null_map) \
+ V(boolean_map) \
+ V(uninitialized_map) \
+ V(message_object_map) \
+ V(foreign_map) \
+ V(neander_map)
+
+#define INTERNALIZED_STRING_LIST(V) \
+ V(Object_string, "Object") \
+ V(proto_string, "__proto__") \
+ V(arguments_string, "arguments") \
+ V(Arguments_string, "Arguments") \
+ V(caller_string, "caller") \
+ V(boolean_string, "boolean") \
+ V(Boolean_string, "Boolean") \
+ V(callee_string, "callee") \
+ V(constructor_string, "constructor") \
+ V(dot_result_string, ".result") \
+ V(dot_for_string, ".for.") \
+ V(eval_string, "eval") \
+ V(empty_string, "") \
+ V(function_string, "function") \
+ V(Function_string, "Function") \
+ V(length_string, "length") \
+ V(name_string, "name") \
+ V(null_string, "null") \
+ V(number_string, "number") \
+ V(Number_string, "Number") \
+ V(nan_string, "NaN") \
+ V(source_string, "source") \
+ V(source_url_string, "source_url") \
+ V(source_mapping_url_string, "source_mapping_url") \
+ V(global_string, "global") \
+ V(ignore_case_string, "ignoreCase") \
+ V(multiline_string, "multiline") \
+ V(sticky_string, "sticky") \
+ V(harmony_regexps_string, "harmony_regexps") \
+ V(input_string, "input") \
+ V(index_string, "index") \
+ V(last_index_string, "lastIndex") \
+ V(object_string, "object") \
+ V(prototype_string, "prototype") \
+ V(string_string, "string") \
+ V(String_string, "String") \
+ V(symbol_string, "symbol") \
+ V(Symbol_string, "Symbol") \
+ V(Map_string, "Map") \
+ V(Set_string, "Set") \
+ V(WeakMap_string, "WeakMap") \
+ V(WeakSet_string, "WeakSet") \
+ V(for_string, "for") \
+ V(for_api_string, "for_api") \
+ V(for_intern_string, "for_intern") \
+ V(private_api_string, "private_api") \
+ V(private_intern_string, "private_intern") \
+ V(Date_string, "Date") \
+ V(char_at_string, "CharAt") \
+ V(undefined_string, "undefined") \
+ V(value_of_string, "valueOf") \
+ V(stack_string, "stack") \
+ V(toJSON_string, "toJSON") \
+ V(KeyedLoadMonomorphic_string, "KeyedLoadMonomorphic") \
+ V(KeyedStoreMonomorphic_string, "KeyedStoreMonomorphic") \
+ V(stack_overflow_string, "kStackOverflowBoilerplate") \
+ V(illegal_access_string, "illegal access") \
+ V(cell_value_string, "%cell_value") \
+ V(illegal_argument_string, "illegal argument") \
+ V(identity_hash_string, "v8::IdentityHash") \
+ V(closure_string, "(closure)") \
+ V(dot_string, ".") \
+ V(compare_ic_string, "==") \
+ V(strict_compare_ic_string, "===") \
+ V(infinity_string, "Infinity") \
+ V(minus_infinity_string, "-Infinity") \
+ V(query_colon_string, "(?:)") \
+ V(Generator_string, "Generator") \
+ V(throw_string, "throw") \
+ V(done_string, "done") \
+ V(value_string, "value") \
+ V(next_string, "next") \
+ V(byte_length_string, "byteLength") \
+ V(byte_offset_string, "byteOffset") \
+ V(intl_initialized_marker_string, "v8::intl_initialized_marker") \
+ V(intl_impl_object_string, "v8::intl_object")
+
+// Forward declarations.
+class HeapStats;
+class Isolate;
+class WeakObjectRetainer;
+
+
+typedef String* (*ExternalStringTableUpdaterCallback)(Heap* heap,
+ Object** pointer);
+
+class StoreBufferRebuilder {
+ public:
+ explicit StoreBufferRebuilder(StoreBuffer* store_buffer)
+ : store_buffer_(store_buffer) {}
+
+ void Callback(MemoryChunk* page, StoreBufferEvent event);
+
+ private:
+ StoreBuffer* store_buffer_;
+
+ // We record in this variable how full the store buffer was when we started
+ // iterating over the current page, finding pointers to new space. If the
+ // store buffer overflows again we can exempt the page from the store buffer
+ // by rewinding to this point instead of having to search the store buffer.
+ Object*** start_of_current_page_;
+ // The current page we are scanning in the store buffer iterator.
+ MemoryChunk* current_page_;
+};
+
+
+// A queue of objects promoted during scavenge. Each object is accompanied
+// by it's size to avoid dereferencing a map pointer for scanning.
+class PromotionQueue {
+ public:
+ explicit PromotionQueue(Heap* heap)
+ : front_(NULL),
+ rear_(NULL),
+ limit_(NULL),
+ emergency_stack_(0),
+ heap_(heap) {}
+
+ void Initialize();
+
+ void Destroy() {
+ DCHECK(is_empty());
+ delete emergency_stack_;
+ emergency_stack_ = NULL;
+ }
+
+ Page* GetHeadPage() {
+ return Page::FromAllocationTop(reinterpret_cast<Address>(rear_));
+ }
+
+ void SetNewLimit(Address limit) {
+ limit_ = reinterpret_cast<intptr_t*>(limit);
+
+ if (limit_ <= rear_) {
+ return;
+ }
+
+ RelocateQueueHead();
+ }
+
+ bool IsBelowPromotionQueue(Address to_space_top) {
+ // If the given to-space top pointer and the head of the promotion queue
+ // are not on the same page, then the to-space objects are below the
+ // promotion queue.
+ if (GetHeadPage() != Page::FromAddress(to_space_top)) {
+ return true;
+ }
+ // If the to space top pointer is smaller or equal than the promotion
+ // queue head, then the to-space objects are below the promotion queue.
+ return reinterpret_cast<intptr_t*>(to_space_top) <= rear_;
+ }
+
+ bool is_empty() {
+ return (front_ == rear_) &&
+ (emergency_stack_ == NULL || emergency_stack_->length() == 0);
+ }
+
+ inline void insert(HeapObject* target, int size);
+
+ void remove(HeapObject** target, int* size) {
+ DCHECK(!is_empty());
+ if (front_ == rear_) {
+ Entry e = emergency_stack_->RemoveLast();
+ *target = e.obj_;
+ *size = e.size_;
+ return;
+ }
+
+ if (NewSpacePage::IsAtStart(reinterpret_cast<Address>(front_))) {
+ NewSpacePage* front_page =
+ NewSpacePage::FromAddress(reinterpret_cast<Address>(front_));
+ DCHECK(!front_page->prev_page()->is_anchor());
+ front_ = reinterpret_cast<intptr_t*>(front_page->prev_page()->area_end());
+ }
+ *target = reinterpret_cast<HeapObject*>(*(--front_));
+ *size = static_cast<int>(*(--front_));
+ // Assert no underflow.
+ SemiSpace::AssertValidRange(reinterpret_cast<Address>(rear_),
+ reinterpret_cast<Address>(front_));
+ }
+
+ private:
+ // The front of the queue is higher in the memory page chain than the rear.
+ intptr_t* front_;
+ intptr_t* rear_;
+ intptr_t* limit_;
+
+ static const int kEntrySizeInWords = 2;
+
+ struct Entry {
+ Entry(HeapObject* obj, int size) : obj_(obj), size_(size) {}
+
+ HeapObject* obj_;
+ int size_;
+ };
+ List<Entry>* emergency_stack_;
+
+ Heap* heap_;
+
+ void RelocateQueueHead();
+
+ DISALLOW_COPY_AND_ASSIGN(PromotionQueue);
+};
+
+
+typedef void (*ScavengingCallback)(Map* map, HeapObject** slot,
+ HeapObject* object);
+
+
+// External strings table is a place where all external strings are
+// registered. We need to keep track of such strings to properly
+// finalize them.
+class ExternalStringTable {
+ public:
+ // Registers an external string.
+ inline void AddString(String* string);
+
+ inline void Iterate(ObjectVisitor* v);
+
+ // Restores internal invariant and gets rid of collected strings.
+ // Must be called after each Iterate() that modified the strings.
+ void CleanUp();
+
+ // Destroys all allocated memory.
+ void TearDown();
+
+ private:
+ explicit ExternalStringTable(Heap* heap) : heap_(heap) {}
+
+ friend class Heap;
+
+ inline void Verify();
+
+ inline void AddOldString(String* string);
+
+ // Notifies the table that only a prefix of the new list is valid.
+ inline void ShrinkNewStrings(int position);
+
+ // To speed up scavenge collections new space string are kept
+ // separate from old space strings.
+ List<Object*> new_space_strings_;
+ List<Object*> old_space_strings_;
+
+ Heap* heap_;
+
+ DISALLOW_COPY_AND_ASSIGN(ExternalStringTable);
+};
+
+
+enum ArrayStorageAllocationMode {
+ DONT_INITIALIZE_ARRAY_ELEMENTS,
+ INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE
+};
+
+
+class Heap {
+ public:
+ // Configure heap size in MB before setup. Return false if the heap has been
+ // set up already.
+ bool ConfigureHeap(int max_semi_space_size, int max_old_space_size,
+ int max_executable_size, size_t code_range_size);
+ bool ConfigureHeapDefault();
+
+ // Prepares the heap, setting up memory areas that are needed in the isolate
+ // without actually creating any objects.
+ bool SetUp();
+
+ // Bootstraps the object heap with the core set of objects required to run.
+ // Returns whether it succeeded.
+ bool CreateHeapObjects();
+
+ // Destroys all memory allocated by the heap.
+ void TearDown();
+
+ // Set the stack limit in the roots_ array. Some architectures generate
+ // code that looks here, because it is faster than loading from the static
+ // jslimit_/real_jslimit_ variable in the StackGuard.
+ void SetStackLimits();
+
+ // Returns whether SetUp has been called.
+ bool HasBeenSetUp();
+
+ // Returns the maximum amount of memory reserved for the heap. For
+ // the young generation, we reserve 4 times the amount needed for a
+ // semi space. The young generation consists of two semi spaces and
+ // we reserve twice the amount needed for those in order to ensure
+ // that new space can be aligned to its size.
+ intptr_t MaxReserved() {
+ return 4 * reserved_semispace_size_ + max_old_generation_size_;
+ }
+ int MaxSemiSpaceSize() { return max_semi_space_size_; }
+ int ReservedSemiSpaceSize() { return reserved_semispace_size_; }
+ int InitialSemiSpaceSize() { return initial_semispace_size_; }
+ intptr_t MaxOldGenerationSize() { return max_old_generation_size_; }
+ intptr_t MaxExecutableSize() { return max_executable_size_; }
+
+ // Returns the capacity of the heap in bytes w/o growing. Heap grows when
+ // more spaces are needed until it reaches the limit.
+ intptr_t Capacity();
+
+ // Returns the amount of memory currently committed for the heap.
+ intptr_t CommittedMemory();
+
+ // Returns the amount of executable memory currently committed for the heap.
+ intptr_t CommittedMemoryExecutable();
+
+ // Returns the amount of phyical memory currently committed for the heap.
+ size_t CommittedPhysicalMemory();
+
+ // Returns the maximum amount of memory ever committed for the heap.
+ intptr_t MaximumCommittedMemory() { return maximum_committed_; }
+
+ // Updates the maximum committed memory for the heap. Should be called
+ // whenever a space grows.
+ void UpdateMaximumCommitted();
+
+ // Returns the available bytes in space w/o growing.
+ // Heap doesn't guarantee that it can allocate an object that requires
+ // all available bytes. Check MaxHeapObjectSize() instead.
+ intptr_t Available();
+
+ // Returns of size of all objects residing in the heap.
+ intptr_t SizeOfObjects();
+
+ // Return the starting address and a mask for the new space. And-masking an
+ // address with the mask will result in the start address of the new space
+ // for all addresses in either semispace.
+ Address NewSpaceStart() { return new_space_.start(); }
+ uintptr_t NewSpaceMask() { return new_space_.mask(); }
+ Address NewSpaceTop() { return new_space_.top(); }
+
+ NewSpace* new_space() { return &new_space_; }
+ OldSpace* old_pointer_space() { return old_pointer_space_; }
+ OldSpace* old_data_space() { return old_data_space_; }
+ OldSpace* code_space() { return code_space_; }
+ MapSpace* map_space() { return map_space_; }
+ CellSpace* cell_space() { return cell_space_; }
+ PropertyCellSpace* property_cell_space() { return property_cell_space_; }
+ LargeObjectSpace* lo_space() { return lo_space_; }
+ PagedSpace* paged_space(int idx) {
+ switch (idx) {
+ case OLD_POINTER_SPACE:
+ return old_pointer_space();
+ case OLD_DATA_SPACE:
+ return old_data_space();
+ case MAP_SPACE:
+ return map_space();
+ case CELL_SPACE:
+ return cell_space();
+ case PROPERTY_CELL_SPACE:
+ return property_cell_space();
+ case CODE_SPACE:
+ return code_space();
+ case NEW_SPACE:
+ case LO_SPACE:
+ UNREACHABLE();
+ }
+ return NULL;
+ }
+
+ bool always_allocate() { return always_allocate_scope_depth_ != 0; }
+ Address always_allocate_scope_depth_address() {
+ return reinterpret_cast<Address>(&always_allocate_scope_depth_);
+ }
+
+ Address* NewSpaceAllocationTopAddress() {
+ return new_space_.allocation_top_address();
+ }
+ Address* NewSpaceAllocationLimitAddress() {
+ return new_space_.allocation_limit_address();
+ }
+
+ Address* OldPointerSpaceAllocationTopAddress() {
+ return old_pointer_space_->allocation_top_address();
+ }
+ Address* OldPointerSpaceAllocationLimitAddress() {
+ return old_pointer_space_->allocation_limit_address();
+ }
+
+ Address* OldDataSpaceAllocationTopAddress() {
+ return old_data_space_->allocation_top_address();
+ }
+ Address* OldDataSpaceAllocationLimitAddress() {
+ return old_data_space_->allocation_limit_address();
+ }
+
+ // Returns a deep copy of the JavaScript object.
+ // Properties and elements are copied too.
+ // Optionally takes an AllocationSite to be appended in an AllocationMemento.
+ MUST_USE_RESULT AllocationResult
+ CopyJSObject(JSObject* source, AllocationSite* site = NULL);
+
+ // Clear the Instanceof cache (used when a prototype changes).
+ inline void ClearInstanceofCache();
+
+ // Iterates the whole code space to clear all ICs of the given kind.
+ void ClearAllICsByKind(Code::Kind kind);
+
+ // For use during bootup.
+ void RepairFreeListsAfterBoot();
+
+ template <typename T>
+ static inline bool IsOneByte(T t, int chars);
+
+ // Move len elements within a given array from src_index index to dst_index
+ // index.
+ void MoveElements(FixedArray* array, int dst_index, int src_index, int len);
+
+ // Sloppy mode arguments object size.
+ static const int kSloppyArgumentsObjectSize =
+ JSObject::kHeaderSize + 2 * kPointerSize;
+ // Strict mode arguments has no callee so it is smaller.
+ static const int kStrictArgumentsObjectSize =
+ JSObject::kHeaderSize + 1 * kPointerSize;
+ // Indicies for direct access into argument objects.
+ static const int kArgumentsLengthIndex = 0;
+ // callee is only valid in sloppy mode.
+ static const int kArgumentsCalleeIndex = 1;
+
+ // Finalizes an external string by deleting the associated external
+ // data and clearing the resource pointer.
+ inline void FinalizeExternalString(String* string);
+
+ // Initialize a filler object to keep the ability to iterate over the heap
+ // when introducing gaps within pages.
+ void CreateFillerObjectAt(Address addr, int size);
+
+ bool CanMoveObjectStart(HeapObject* object);
+
+ // Indicates whether live bytes adjustment is triggered from within the GC
+ // code or from mutator code.
+ enum InvocationMode { FROM_GC, FROM_MUTATOR };
+
+ // Maintain consistency of live bytes during incremental marking.
+ void AdjustLiveBytes(Address address, int by, InvocationMode mode);
+
+ // Trim the given array from the left. Note that this relocates the object
+ // start and hence is only valid if there is only a single reference to it.
+ FixedArrayBase* LeftTrimFixedArray(FixedArrayBase* obj, int elements_to_trim);
+
+ // Trim the given array from the right.
+ template<Heap::InvocationMode mode>
+ void RightTrimFixedArray(FixedArrayBase* obj, int elements_to_trim);
+
+ // Converts the given boolean condition to JavaScript boolean value.
+ inline Object* ToBoolean(bool condition);
+
+ // Performs garbage collection operation.
+ // Returns whether there is a chance that another major GC could
+ // collect more garbage.
+ inline bool CollectGarbage(
+ AllocationSpace space, const char* gc_reason = NULL,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ static const int kNoGCFlags = 0;
+ static const int kReduceMemoryFootprintMask = 1;
+ static const int kAbortIncrementalMarkingMask = 2;
+
+ // Making the heap iterable requires us to abort incremental marking.
+ static const int kMakeHeapIterableMask = kAbortIncrementalMarkingMask;
+
+ // Performs a full garbage collection. If (flags & kMakeHeapIterableMask) is
+ // non-zero, then the slower precise sweeper is used, which leaves the heap
+ // in a state where we can iterate over the heap visiting all objects.
+ void CollectAllGarbage(
+ int flags, const char* gc_reason = NULL,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ // Last hope GC, should try to squeeze as much as possible.
+ void CollectAllAvailableGarbage(const char* gc_reason = NULL);
+
+ // Check whether the heap is currently iterable.
+ bool IsHeapIterable();
+
+ // Notify the heap that a context has been disposed.
+ int NotifyContextDisposed();
+
+ inline void increment_scan_on_scavenge_pages() {
+ scan_on_scavenge_pages_++;
+ if (FLAG_gc_verbose) {
+ PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
+ }
+ }
+
+ inline void decrement_scan_on_scavenge_pages() {
+ scan_on_scavenge_pages_--;
+ if (FLAG_gc_verbose) {
+ PrintF("Scan-on-scavenge pages: %d\n", scan_on_scavenge_pages_);
+ }
+ }
+
+ PromotionQueue* promotion_queue() { return &promotion_queue_; }
+
+ void AddGCPrologueCallback(v8::Isolate::GCPrologueCallback callback,
+ GCType gc_type_filter, bool pass_isolate = true);
+ void RemoveGCPrologueCallback(v8::Isolate::GCPrologueCallback callback);
+
+ void AddGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback,
+ GCType gc_type_filter, bool pass_isolate = true);
+ void RemoveGCEpilogueCallback(v8::Isolate::GCEpilogueCallback callback);
+
+// Heap root getters. We have versions with and without type::cast() here.
+// You can't use type::cast during GC because the assert fails.
+// TODO(1490): Try removing the unchecked accessors, now that GC marking does
+// not corrupt the map.
+#define ROOT_ACCESSOR(type, name, camel_name) \
+ type* name() { return type::cast(roots_[k##camel_name##RootIndex]); } \
+ type* raw_unchecked_##name() { \
+ return reinterpret_cast<type*>(roots_[k##camel_name##RootIndex]); \
+ }
+ ROOT_LIST(ROOT_ACCESSOR)
+#undef ROOT_ACCESSOR
+
+// Utility type maps
+#define STRUCT_MAP_ACCESSOR(NAME, Name, name) \
+ Map* name##_map() { return Map::cast(roots_[k##Name##MapRootIndex]); }
+ STRUCT_LIST(STRUCT_MAP_ACCESSOR)
+#undef STRUCT_MAP_ACCESSOR
+
+#define STRING_ACCESSOR(name, str) \
+ String* name() { return String::cast(roots_[k##name##RootIndex]); }
+ INTERNALIZED_STRING_LIST(STRING_ACCESSOR)
+#undef STRING_ACCESSOR
+
+ // The hidden_string is special because it is the empty string, but does
+ // not match the empty string.
+ String* hidden_string() { return hidden_string_; }
+
+ void set_native_contexts_list(Object* object) {
+ native_contexts_list_ = object;
+ }
+ Object* native_contexts_list() const { return native_contexts_list_; }
+
+ void set_array_buffers_list(Object* object) { array_buffers_list_ = object; }
+ Object* array_buffers_list() const { return array_buffers_list_; }
+
+ void set_allocation_sites_list(Object* object) {
+ allocation_sites_list_ = object;
+ }
+ Object* allocation_sites_list() { return allocation_sites_list_; }
+
+ // Used in CreateAllocationSiteStub and the (de)serializer.
+ Object** allocation_sites_list_address() { return &allocation_sites_list_; }
+
+ Object* weak_object_to_code_table() { return weak_object_to_code_table_; }
+
+ void set_encountered_weak_collections(Object* weak_collection) {
+ encountered_weak_collections_ = weak_collection;
+ }
+ Object* encountered_weak_collections() const {
+ return encountered_weak_collections_;
+ }
+
+ // Number of mark-sweeps.
+ unsigned int ms_count() { return ms_count_; }
+
+ // Iterates over all roots in the heap.
+ void IterateRoots(ObjectVisitor* v, VisitMode mode);
+ // Iterates over all strong roots in the heap.
+ void IterateStrongRoots(ObjectVisitor* v, VisitMode mode);
+ // Iterates over entries in the smi roots list. Only interesting to the
+ // serializer/deserializer, since GC does not care about smis.
+ void IterateSmiRoots(ObjectVisitor* v);
+ // Iterates over all the other roots in the heap.
+ void IterateWeakRoots(ObjectVisitor* v, VisitMode mode);
+
+ // Iterate pointers to from semispace of new space found in memory interval
+ // from start to end.
+ void IterateAndMarkPointersToFromSpace(Address start, Address end,
+ ObjectSlotCallback callback);
+
+ // Returns whether the object resides in new space.
+ inline bool InNewSpace(Object* object);
+ inline bool InNewSpace(Address address);
+ inline bool InNewSpacePage(Address address);
+ inline bool InFromSpace(Object* object);
+ inline bool InToSpace(Object* object);
+
+ // Returns whether the object resides in old pointer space.
+ inline bool InOldPointerSpace(Address address);
+ inline bool InOldPointerSpace(Object* object);
+
+ // Returns whether the object resides in old data space.
+ inline bool InOldDataSpace(Address address);
+ inline bool InOldDataSpace(Object* object);
+
+ // Checks whether an address/object in the heap (including auxiliary
+ // area and unused area).
+ bool Contains(Address addr);
+ bool Contains(HeapObject* value);
+
+ // Checks whether an address/object in a space.
+ // Currently used by tests, serialization and heap verification only.
+ bool InSpace(Address addr, AllocationSpace space);
+ bool InSpace(HeapObject* value, AllocationSpace space);
+
+ // Finds out which space an object should get promoted to based on its type.
+ inline OldSpace* TargetSpace(HeapObject* object);
+ static inline AllocationSpace TargetSpaceId(InstanceType type);
+
+ // Checks whether the given object is allowed to be migrated from it's
+ // current space into the given destination space. Used for debugging.
+ inline bool AllowedToBeMigrated(HeapObject* object, AllocationSpace dest);
+
+ // Sets the stub_cache_ (only used when expanding the dictionary).
+ void public_set_code_stubs(UnseededNumberDictionary* value) {
+ roots_[kCodeStubsRootIndex] = value;
+ }
+
+ // Support for computing object sizes for old objects during GCs. Returns
+ // a function that is guaranteed to be safe for computing object sizes in
+ // the current GC phase.
+ HeapObjectCallback GcSafeSizeOfOldObjectFunction() {
+ return gc_safe_size_of_old_object_;
+ }
+
+ // Sets the non_monomorphic_cache_ (only used when expanding the dictionary).
+ void public_set_non_monomorphic_cache(UnseededNumberDictionary* value) {
+ roots_[kNonMonomorphicCacheRootIndex] = value;
+ }
+
+ void public_set_empty_script(Script* script) {
+ roots_[kEmptyScriptRootIndex] = script;
+ }
+
+ void public_set_store_buffer_top(Address* top) {
+ roots_[kStoreBufferTopRootIndex] = reinterpret_cast<Smi*>(top);
+ }
+
+ void public_set_materialized_objects(FixedArray* objects) {
+ roots_[kMaterializedObjectsRootIndex] = objects;
+ }
+
+ // Generated code can embed this address to get access to the roots.
+ Object** roots_array_start() { return roots_; }
+
+ Address* store_buffer_top_address() {
+ return reinterpret_cast<Address*>(&roots_[kStoreBufferTopRootIndex]);
+ }
+
+#ifdef VERIFY_HEAP
+ // Verify the heap is in its normal state before or after a GC.
+ void Verify();
+
+
+ bool weak_embedded_objects_verification_enabled() {
+ return no_weak_object_verification_scope_depth_ == 0;
+ }
+#endif
+
+#ifdef DEBUG
+ void Print();
+ void PrintHandles();
+
+ void OldPointerSpaceCheckStoreBuffer();
+ void MapSpaceCheckStoreBuffer();
+ void LargeObjectSpaceCheckStoreBuffer();
+
+ // Report heap statistics.
+ void ReportHeapStatistics(const char* title);
+ void ReportCodeStatistics(const char* title);
+#endif
+
+ // Zapping is needed for verify heap, and always done in debug builds.
+ static inline bool ShouldZapGarbage() {
+#ifdef DEBUG
+ return true;
+#else
+#ifdef VERIFY_HEAP
+ return FLAG_verify_heap;
+#else
+ return false;
+#endif
+#endif
+ }
+
+ // Number of "runtime allocations" done so far.
+ uint32_t allocations_count() { return allocations_count_; }
+
+ // Returns deterministic "time" value in ms. Works only with
+ // FLAG_verify_predictable.
+ double synthetic_time() { return allocations_count_ / 2.0; }
+
+ // Print short heap statistics.
+ void PrintShortHeapStatistics();
+
+ // Write barrier support for address[offset] = o.
+ INLINE(void RecordWrite(Address address, int offset));
+
+ // Write barrier support for address[start : start + len[ = o.
+ INLINE(void RecordWrites(Address address, int start, int len));
+
+ enum HeapState { NOT_IN_GC, SCAVENGE, MARK_COMPACT };
+ inline HeapState gc_state() { return gc_state_; }
+
+ inline bool IsInGCPostProcessing() { return gc_post_processing_depth_ > 0; }
+
+#ifdef DEBUG
+ void set_allocation_timeout(int timeout) { allocation_timeout_ = timeout; }
+
+ void TracePathToObjectFrom(Object* target, Object* root);
+ void TracePathToObject(Object* target);
+ void TracePathToGlobal();
+#endif
+
+ // Callback function passed to Heap::Iterate etc. Copies an object if
+ // necessary, the object might be promoted to an old space. The caller must
+ // ensure the precondition that the object is (a) a heap object and (b) in
+ // the heap's from space.
+ static inline void ScavengePointer(HeapObject** p);
+ static inline void ScavengeObject(HeapObject** p, HeapObject* object);
+
+ enum ScratchpadSlotMode { IGNORE_SCRATCHPAD_SLOT, RECORD_SCRATCHPAD_SLOT };
+
+ // If an object has an AllocationMemento trailing it, return it, otherwise
+ // return NULL;
+ inline AllocationMemento* FindAllocationMemento(HeapObject* object);
+
+ // An object may have an AllocationSite associated with it through a trailing
+ // AllocationMemento. Its feedback should be updated when objects are found
+ // in the heap.
+ static inline void UpdateAllocationSiteFeedback(HeapObject* object,
+ ScratchpadSlotMode mode);
+
+ // Support for partial snapshots. After calling this we have a linear
+ // space to write objects in each space.
+ void ReserveSpace(int* sizes, Address* addresses);
+
+ //
+ // Support for the API.
+ //
+
+ void CreateApiObjects();
+
+ inline intptr_t PromotedTotalSize() {
+ int64_t total = PromotedSpaceSizeOfObjects() + PromotedExternalMemorySize();
+ if (total > kMaxInt) return static_cast<intptr_t>(kMaxInt);
+ if (total < 0) return 0;
+ return static_cast<intptr_t>(total);
+ }
+
+ inline intptr_t OldGenerationSpaceAvailable() {
+ return old_generation_allocation_limit_ - PromotedTotalSize();
+ }
+
+ inline intptr_t OldGenerationCapacityAvailable() {
+ return max_old_generation_size_ - PromotedTotalSize();
+ }
+
+ static const intptr_t kMinimumOldGenerationAllocationLimit =
+ 8 * (Page::kPageSize > MB ? Page::kPageSize : MB);
+
+ static const int kPointerMultiplier = i::kPointerSize / 4;
+
+ // The new space size has to be a power of 2. Sizes are in MB.
+ static const int kMaxSemiSpaceSizeLowMemoryDevice = 1 * kPointerMultiplier;
+ static const int kMaxSemiSpaceSizeMediumMemoryDevice = 4 * kPointerMultiplier;
+ static const int kMaxSemiSpaceSizeHighMemoryDevice = 8 * kPointerMultiplier;
+ static const int kMaxSemiSpaceSizeHugeMemoryDevice = 8 * kPointerMultiplier;
+
+ // The old space size has to be a multiple of Page::kPageSize.
+ // Sizes are in MB.
+ static const int kMaxOldSpaceSizeLowMemoryDevice = 128 * kPointerMultiplier;
+ static const int kMaxOldSpaceSizeMediumMemoryDevice =
+ 256 * kPointerMultiplier;
+ static const int kMaxOldSpaceSizeHighMemoryDevice = 512 * kPointerMultiplier;
+ static const int kMaxOldSpaceSizeHugeMemoryDevice = 700 * kPointerMultiplier;
+
+ // The executable size has to be a multiple of Page::kPageSize.
+ // Sizes are in MB.
+ static const int kMaxExecutableSizeLowMemoryDevice = 96 * kPointerMultiplier;
+ static const int kMaxExecutableSizeMediumMemoryDevice =
+ 192 * kPointerMultiplier;
+ static const int kMaxExecutableSizeHighMemoryDevice =
+ 256 * kPointerMultiplier;
+ static const int kMaxExecutableSizeHugeMemoryDevice =
+ 256 * kPointerMultiplier;
+
+ intptr_t OldGenerationAllocationLimit(intptr_t old_gen_size,
+ int freed_global_handles);
+
+ // Indicates whether inline bump-pointer allocation has been disabled.
+ bool inline_allocation_disabled() { return inline_allocation_disabled_; }
+
+ // Switch whether inline bump-pointer allocation should be used.
+ void EnableInlineAllocation();
+ void DisableInlineAllocation();
+
+ // Implements the corresponding V8 API function.
+ bool IdleNotification(int idle_time_in_ms);
+
+ // Declare all the root indices. This defines the root list order.
+ enum RootListIndex {
+#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
+ STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION)
+#undef ROOT_INDEX_DECLARATION
+
+#define STRING_INDEX_DECLARATION(name, str) k##name##RootIndex,
+ INTERNALIZED_STRING_LIST(STRING_INDEX_DECLARATION)
+#undef STRING_DECLARATION
+
+// Utility type maps
+#define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex,
+ STRUCT_LIST(DECLARE_STRUCT_MAP)
+#undef DECLARE_STRUCT_MAP
+ kStringTableRootIndex,
+
+#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
+ SMI_ROOT_LIST(ROOT_INDEX_DECLARATION)
+#undef ROOT_INDEX_DECLARATION
+ kRootListLength,
+ kStrongRootListLength = kStringTableRootIndex,
+ kSmiRootsStart = kStringTableRootIndex + 1
+ };
+
+ STATIC_ASSERT(kUndefinedValueRootIndex ==
+ Internals::kUndefinedValueRootIndex);
+ STATIC_ASSERT(kNullValueRootIndex == Internals::kNullValueRootIndex);
+ STATIC_ASSERT(kTrueValueRootIndex == Internals::kTrueValueRootIndex);
+ STATIC_ASSERT(kFalseValueRootIndex == Internals::kFalseValueRootIndex);
+ STATIC_ASSERT(kempty_stringRootIndex == Internals::kEmptyStringRootIndex);
+
+ // Generated code can embed direct references to non-writable roots if
+ // they are in new space.
+ static bool RootCanBeWrittenAfterInitialization(RootListIndex root_index);
+ // Generated code can treat direct references to this root as constant.
+ bool RootCanBeTreatedAsConstant(RootListIndex root_index);
+
+ Map* MapForFixedTypedArray(ExternalArrayType array_type);
+ RootListIndex RootIndexForFixedTypedArray(ExternalArrayType array_type);
+
+ Map* MapForExternalArrayType(ExternalArrayType array_type);
+ RootListIndex RootIndexForExternalArrayType(ExternalArrayType array_type);
+
+ RootListIndex RootIndexForEmptyExternalArray(ElementsKind kind);
+ RootListIndex RootIndexForEmptyFixedTypedArray(ElementsKind kind);
+ ExternalArray* EmptyExternalArrayForMap(Map* map);
+ FixedTypedArrayBase* EmptyFixedTypedArrayForMap(Map* map);
+
+ void RecordStats(HeapStats* stats, bool take_snapshot = false);
+
+ // Copy block of memory from src to dst. Size of block should be aligned
+ // by pointer size.
+ static inline void CopyBlock(Address dst, Address src, int byte_size);
+
+ // Optimized version of memmove for blocks with pointer size aligned sizes and
+ // pointer size aligned addresses.
+ static inline void MoveBlock(Address dst, Address src, int byte_size);
+
+ // Check new space expansion criteria and expand semispaces if it was hit.
+ void CheckNewSpaceExpansionCriteria();
+
+ inline void IncrementPromotedObjectsSize(int object_size) {
+ DCHECK(object_size > 0);
+ promoted_objects_size_ += object_size;
+ }
+
+ inline void IncrementSemiSpaceCopiedObjectSize(int object_size) {
+ DCHECK(object_size > 0);
+ semi_space_copied_object_size_ += object_size;
+ }
+
+ inline void IncrementNodesDiedInNewSpace() { nodes_died_in_new_space_++; }
+
+ inline void IncrementNodesCopiedInNewSpace() { nodes_copied_in_new_space_++; }
+
+ inline void IncrementNodesPromoted() { nodes_promoted_++; }
+
+ inline void IncrementYoungSurvivorsCounter(int survived) {
+ DCHECK(survived >= 0);
+ survived_since_last_expansion_ += survived;
+ }
+
+ inline bool NextGCIsLikelyToBeFull() {
+ if (FLAG_gc_global) return true;
+
+ if (FLAG_stress_compaction && (gc_count_ & 1) != 0) return true;
+
+ intptr_t adjusted_allocation_limit =
+ old_generation_allocation_limit_ - new_space_.Capacity();
+
+ if (PromotedTotalSize() >= adjusted_allocation_limit) return true;
+
+ return false;
+ }
+
+ void UpdateNewSpaceReferencesInExternalStringTable(
+ ExternalStringTableUpdaterCallback updater_func);
+
+ void UpdateReferencesInExternalStringTable(
+ ExternalStringTableUpdaterCallback updater_func);
+
+ void ProcessWeakReferences(WeakObjectRetainer* retainer);
+
+ void VisitExternalResources(v8::ExternalResourceVisitor* visitor);
+
+ // An object should be promoted if the object has survived a
+ // scavenge operation.
+ inline bool ShouldBePromoted(Address old_address, int object_size);
+
+ void ClearJSFunctionResultCaches();
+
+ void ClearNormalizedMapCaches();
+
+ GCTracer* tracer() { return &tracer_; }
+
+ // Returns the size of objects residing in non new spaces.
+ intptr_t PromotedSpaceSizeOfObjects();
+
+ double total_regexp_code_generated() { return total_regexp_code_generated_; }
+ void IncreaseTotalRegexpCodeGenerated(int size) {
+ total_regexp_code_generated_ += size;
+ }
+
+ void IncrementCodeGeneratedBytes(bool is_crankshafted, int size) {
+ if (is_crankshafted) {
+ crankshaft_codegen_bytes_generated_ += size;
+ } else {
+ full_codegen_bytes_generated_ += size;
+ }
+ }
+
+ // Update GC statistics that are tracked on the Heap.
+ void UpdateCumulativeGCStatistics(double duration, double spent_in_mutator,
+ double marking_time);
+
+ // Returns maximum GC pause.
+ double get_max_gc_pause() { return max_gc_pause_; }
+
+ // Returns maximum size of objects alive after GC.
+ intptr_t get_max_alive_after_gc() { return max_alive_after_gc_; }
+
+ // Returns minimal interval between two subsequent collections.
+ double get_min_in_mutator() { return min_in_mutator_; }
+
+ MarkCompactCollector* mark_compact_collector() {
+ return &mark_compact_collector_;
+ }
+
+ StoreBuffer* store_buffer() { return &store_buffer_; }
+
+ Marking* marking() { return &marking_; }
+
+ IncrementalMarking* incremental_marking() { return &incremental_marking_; }
+
+ ExternalStringTable* external_string_table() {
+ return &external_string_table_;
+ }
+
+ // Returns the current sweep generation.
+ int sweep_generation() { return sweep_generation_; }
+
+ inline Isolate* isolate();
+
+ void CallGCPrologueCallbacks(GCType gc_type, GCCallbackFlags flags);
+ void CallGCEpilogueCallbacks(GCType gc_type, GCCallbackFlags flags);
+
+ inline bool OldGenerationAllocationLimitReached();
+
+ inline void DoScavengeObject(Map* map, HeapObject** slot, HeapObject* obj) {
+ scavenging_visitors_table_.GetVisitor(map)(map, slot, obj);
+ }
+
+ void QueueMemoryChunkForFree(MemoryChunk* chunk);
+ void FreeQueuedChunks();
+
+ int gc_count() const { return gc_count_; }
+
+ // Completely clear the Instanceof cache (to stop it keeping objects alive
+ // around a GC).
+ inline void CompletelyClearInstanceofCache();
+
+ // The roots that have an index less than this are always in old space.
+ static const int kOldSpaceRoots = 0x20;
+
+ uint32_t HashSeed() {
+ uint32_t seed = static_cast<uint32_t>(hash_seed()->value());
+ DCHECK(FLAG_randomize_hashes || seed == 0);
+ return seed;
+ }
+
+ void SetArgumentsAdaptorDeoptPCOffset(int pc_offset) {
+ DCHECK(arguments_adaptor_deopt_pc_offset() == Smi::FromInt(0));
+ set_arguments_adaptor_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ void SetConstructStubDeoptPCOffset(int pc_offset) {
+ DCHECK(construct_stub_deopt_pc_offset() == Smi::FromInt(0));
+ set_construct_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ void SetGetterStubDeoptPCOffset(int pc_offset) {
+ DCHECK(getter_stub_deopt_pc_offset() == Smi::FromInt(0));
+ set_getter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ void SetSetterStubDeoptPCOffset(int pc_offset) {
+ DCHECK(setter_stub_deopt_pc_offset() == Smi::FromInt(0));
+ set_setter_stub_deopt_pc_offset(Smi::FromInt(pc_offset));
+ }
+
+ // For post mortem debugging.
+ void RememberUnmappedPage(Address page, bool compacted);
+
+ // Global inline caching age: it is incremented on some GCs after context
+ // disposal. We use it to flush inline caches.
+ int global_ic_age() { return global_ic_age_; }
+
+ void AgeInlineCaches() {
+ global_ic_age_ = (global_ic_age_ + 1) & SharedFunctionInfo::ICAgeBits::kMax;
+ }
+
+ bool flush_monomorphic_ics() { return flush_monomorphic_ics_; }
+
+ int64_t amount_of_external_allocated_memory() {
+ return amount_of_external_allocated_memory_;
+ }
+
+ void DeoptMarkedAllocationSites();
+
+ bool MaximumSizeScavenge() { return maximum_size_scavenges_ > 0; }
+
+ bool DeoptMaybeTenuredAllocationSites() {
+ return new_space_.IsAtMaximumCapacity() && maximum_size_scavenges_ == 0;
+ }
+
+ // ObjectStats are kept in two arrays, counts and sizes. Related stats are
+ // stored in a contiguous linear buffer. Stats groups are stored one after
+ // another.
+ enum {
+ FIRST_CODE_KIND_SUB_TYPE = LAST_TYPE + 1,
+ FIRST_FIXED_ARRAY_SUB_TYPE =
+ FIRST_CODE_KIND_SUB_TYPE + Code::NUMBER_OF_KINDS,
+ FIRST_CODE_AGE_SUB_TYPE =
+ FIRST_FIXED_ARRAY_SUB_TYPE + LAST_FIXED_ARRAY_SUB_TYPE + 1,
+ OBJECT_STATS_COUNT = FIRST_CODE_AGE_SUB_TYPE + Code::kCodeAgeCount + 1
+ };
+
+ void RecordObjectStats(InstanceType type, size_t size) {
+ DCHECK(type <= LAST_TYPE);
+ object_counts_[type]++;
+ object_sizes_[type] += size;
+ }
+
+ void RecordCodeSubTypeStats(int code_sub_type, int code_age, size_t size) {
+ int code_sub_type_index = FIRST_CODE_KIND_SUB_TYPE + code_sub_type;
+ int code_age_index =
+ FIRST_CODE_AGE_SUB_TYPE + code_age - Code::kFirstCodeAge;
+ DCHECK(code_sub_type_index >= FIRST_CODE_KIND_SUB_TYPE &&
+ code_sub_type_index < FIRST_CODE_AGE_SUB_TYPE);
+ DCHECK(code_age_index >= FIRST_CODE_AGE_SUB_TYPE &&
+ code_age_index < OBJECT_STATS_COUNT);
+ object_counts_[code_sub_type_index]++;
+ object_sizes_[code_sub_type_index] += size;
+ object_counts_[code_age_index]++;
+ object_sizes_[code_age_index] += size;
+ }
+
+ void RecordFixedArraySubTypeStats(int array_sub_type, size_t size) {
+ DCHECK(array_sub_type <= LAST_FIXED_ARRAY_SUB_TYPE);
+ object_counts_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type]++;
+ object_sizes_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type] += size;
+ }
+
+ void CheckpointObjectStats();
+
+ // We don't use a LockGuard here since we want to lock the heap
+ // only when FLAG_concurrent_recompilation is true.
+ class RelocationLock {
+ public:
+ explicit RelocationLock(Heap* heap) : heap_(heap) {
+ heap_->relocation_mutex_.Lock();
+ }
+
+
+ ~RelocationLock() { heap_->relocation_mutex_.Unlock(); }
+
+ private:
+ Heap* heap_;
+ };
+
+ void AddWeakObjectToCodeDependency(Handle<Object> obj,
+ Handle<DependentCode> dep);
+
+ DependentCode* LookupWeakObjectToCodeDependency(Handle<Object> obj);
+
+ void InitializeWeakObjectToCodeTable() {
+ set_weak_object_to_code_table(undefined_value());
+ }
+
+ void EnsureWeakObjectToCodeTable();
+
+ static void FatalProcessOutOfMemory(const char* location,
+ bool take_snapshot = false);
+
+ // This event is triggered after successful allocation of a new object made
+ // by runtime. Allocations of target space for object evacuation do not
+ // trigger the event. In order to track ALL allocations one must turn off
+ // FLAG_inline_new and FLAG_use_allocation_folding.
+ inline void OnAllocationEvent(HeapObject* object, int size_in_bytes);
+
+ // This event is triggered after object is moved to a new place.
+ inline void OnMoveEvent(HeapObject* target, HeapObject* source,
+ int size_in_bytes);
+
+ protected:
+ // Methods made available to tests.
+
+ // Allocates a JS Map in the heap.
+ MUST_USE_RESULT AllocationResult
+ AllocateMap(InstanceType instance_type, int instance_size,
+ ElementsKind elements_kind = TERMINAL_FAST_ELEMENTS_KIND);
+
+ // Allocates and initializes a new JavaScript object based on a
+ // constructor.
+ // If allocation_site is non-null, then a memento is emitted after the object
+ // that points to the site.
+ MUST_USE_RESULT AllocationResult
+ AllocateJSObject(JSFunction* constructor,
+ PretenureFlag pretenure = NOT_TENURED,
+ AllocationSite* allocation_site = NULL);
+
+ // Allocates and initializes a new JavaScript object based on a map.
+ // Passing an allocation site means that a memento will be created that
+ // points to the site.
+ MUST_USE_RESULT AllocationResult
+ AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure = NOT_TENURED,
+ bool alloc_props = true,
+ AllocationSite* allocation_site = NULL);
+
+ // Allocated a HeapNumber from value.
+ MUST_USE_RESULT AllocationResult
+ AllocateHeapNumber(double value, MutableMode mode = IMMUTABLE,
+ PretenureFlag pretenure = NOT_TENURED);
+
+ // Allocate a byte array of the specified length
+ MUST_USE_RESULT AllocationResult
+ AllocateByteArray(int length, PretenureFlag pretenure = NOT_TENURED);
+
+ // Copy the code and scope info part of the code object, but insert
+ // the provided data as the relocation information.
+ MUST_USE_RESULT AllocationResult
+ CopyCode(Code* code, Vector<byte> reloc_info);
+
+ MUST_USE_RESULT AllocationResult CopyCode(Code* code);
+
+ // Allocates a fixed array initialized with undefined values
+ MUST_USE_RESULT AllocationResult
+ AllocateFixedArray(int length, PretenureFlag pretenure = NOT_TENURED);
+
+ private:
+ Heap();
+
+ // The amount of external memory registered through the API kept alive
+ // by global handles
+ int64_t amount_of_external_allocated_memory_;
+
+ // Caches the amount of external memory registered at the last global gc.
+ int64_t amount_of_external_allocated_memory_at_last_global_gc_;
+
+ // This can be calculated directly from a pointer to the heap; however, it is
+ // more expedient to get at the isolate directly from within Heap methods.
+ Isolate* isolate_;
+
+ Object* roots_[kRootListLength];
+
+ size_t code_range_size_;
+ int reserved_semispace_size_;
+ int max_semi_space_size_;
+ int initial_semispace_size_;
+ intptr_t max_old_generation_size_;
+ intptr_t max_executable_size_;
+ intptr_t maximum_committed_;
+
+ // For keeping track of how much data has survived
+ // scavenge since last new space expansion.
+ int survived_since_last_expansion_;
+
+ // For keeping track on when to flush RegExp code.
+ int sweep_generation_;
+
+ int always_allocate_scope_depth_;
+
+ // For keeping track of context disposals.
+ int contexts_disposed_;
+
+ int global_ic_age_;
+
+ bool flush_monomorphic_ics_;
+
+ int scan_on_scavenge_pages_;
+
+ NewSpace new_space_;
+ OldSpace* old_pointer_space_;
+ OldSpace* old_data_space_;
+ OldSpace* code_space_;
+ MapSpace* map_space_;
+ CellSpace* cell_space_;
+ PropertyCellSpace* property_cell_space_;
+ LargeObjectSpace* lo_space_;
+ HeapState gc_state_;
+ int gc_post_processing_depth_;
+ Address new_space_top_after_last_gc_;
+
+ // Returns the amount of external memory registered since last global gc.
+ int64_t PromotedExternalMemorySize();
+
+ // How many "runtime allocations" happened.
+ uint32_t allocations_count_;
+
+ // Running hash over allocations performed.
+ uint32_t raw_allocations_hash_;
+
+ // Countdown counter, dumps allocation hash when 0.
+ uint32_t dump_allocations_hash_countdown_;
+
+ // How many mark-sweep collections happened.
+ unsigned int ms_count_;
+
+ // How many gc happened.
+ unsigned int gc_count_;
+
+ // For post mortem debugging.
+ static const int kRememberedUnmappedPages = 128;
+ int remembered_unmapped_pages_index_;
+ Address remembered_unmapped_pages_[kRememberedUnmappedPages];
+
+ // Total length of the strings we failed to flatten since the last GC.
+ int unflattened_strings_length_;
+
+#define ROOT_ACCESSOR(type, name, camel_name) \
+ inline void set_##name(type* value) { \
+ /* The deserializer makes use of the fact that these common roots are */ \
+ /* never in new space and never on a page that is being compacted. */ \
+ DCHECK(k##camel_name##RootIndex >= kOldSpaceRoots || !InNewSpace(value)); \
+ roots_[k##camel_name##RootIndex] = value; \
+ }
+ ROOT_LIST(ROOT_ACCESSOR)
+#undef ROOT_ACCESSOR
+
+#ifdef DEBUG
+ // If the --gc-interval flag is set to a positive value, this
+ // variable holds the value indicating the number of allocations
+ // remain until the next failure and garbage collection.
+ int allocation_timeout_;
+#endif // DEBUG
+
+ // Limit that triggers a global GC on the next (normally caused) GC. This
+ // is checked when we have already decided to do a GC to help determine
+ // which collector to invoke, before expanding a paged space in the old
+ // generation and on every allocation in large object space.
+ intptr_t old_generation_allocation_limit_;
+
+ // Indicates that an allocation has failed in the old generation since the
+ // last GC.
+ bool old_gen_exhausted_;
+
+ // Indicates that inline bump-pointer allocation has been globally disabled
+ // for all spaces. This is used to disable allocations in generated code.
+ bool inline_allocation_disabled_;
+
+ // Weak list heads, threaded through the objects.
+ // List heads are initilized lazily and contain the undefined_value at start.
+ Object* native_contexts_list_;
+ Object* array_buffers_list_;
+ Object* allocation_sites_list_;
+
+ // WeakHashTable that maps objects embedded in optimized code to dependent
+ // code list. It is initilized lazily and contains the undefined_value at
+ // start.
+ Object* weak_object_to_code_table_;
+
+ // List of encountered weak collections (JSWeakMap and JSWeakSet) during
+ // marking. It is initialized during marking, destroyed after marking and
+ // contains Smi(0) while marking is not active.
+ Object* encountered_weak_collections_;
+
+ StoreBufferRebuilder store_buffer_rebuilder_;
+
+ struct StringTypeTable {
+ InstanceType type;
+ int size;
+ RootListIndex index;
+ };
+
+ struct ConstantStringTable {
+ const char* contents;
+ RootListIndex index;
+ };
+
+ struct StructTable {
+ InstanceType type;
+ int size;
+ RootListIndex index;
+ };
+
+ static const StringTypeTable string_type_table[];
+ static const ConstantStringTable constant_string_table[];
+ static const StructTable struct_table[];
+
+ // The special hidden string which is an empty string, but does not match
+ // any string when looked up in properties.
+ String* hidden_string_;
+
+ // GC callback function, called before and after mark-compact GC.
+ // Allocations in the callback function are disallowed.
+ struct GCPrologueCallbackPair {
+ GCPrologueCallbackPair(v8::Isolate::GCPrologueCallback callback,
+ GCType gc_type, bool pass_isolate)
+ : callback(callback), gc_type(gc_type), pass_isolate_(pass_isolate) {}
+ bool operator==(const GCPrologueCallbackPair& pair) const {
+ return pair.callback == callback;
+ }
+ v8::Isolate::GCPrologueCallback callback;
+ GCType gc_type;
+ // TODO(dcarney): remove variable
+ bool pass_isolate_;
+ };
+ List<GCPrologueCallbackPair> gc_prologue_callbacks_;
+
+ struct GCEpilogueCallbackPair {
+ GCEpilogueCallbackPair(v8::Isolate::GCPrologueCallback callback,
+ GCType gc_type, bool pass_isolate)
+ : callback(callback), gc_type(gc_type), pass_isolate_(pass_isolate) {}
+ bool operator==(const GCEpilogueCallbackPair& pair) const {
+ return pair.callback == callback;
+ }
+ v8::Isolate::GCPrologueCallback callback;
+ GCType gc_type;
+ // TODO(dcarney): remove variable
+ bool pass_isolate_;
+ };
+ List<GCEpilogueCallbackPair> gc_epilogue_callbacks_;
+
+ // Support for computing object sizes during GC.
+ HeapObjectCallback gc_safe_size_of_old_object_;
+ static int GcSafeSizeOfOldObject(HeapObject* object);
+
+ // Update the GC state. Called from the mark-compact collector.
+ void MarkMapPointersAsEncoded(bool encoded) {
+ DCHECK(!encoded);
+ gc_safe_size_of_old_object_ = &GcSafeSizeOfOldObject;
+ }
+
+ // Code that should be run before and after each GC. Includes some
+ // reporting/verification activities when compiled with DEBUG set.
+ void GarbageCollectionPrologue();
+ void GarbageCollectionEpilogue();
+
+ // Pretenuring decisions are made based on feedback collected during new
+ // space evacuation. Note that between feedback collection and calling this
+ // method object in old space must not move.
+ // Right now we only process pretenuring feedback in high promotion mode.
+ void ProcessPretenuringFeedback();
+
+ // Checks whether a global GC is necessary
+ GarbageCollector SelectGarbageCollector(AllocationSpace space,
+ const char** reason);
+
+ // Make sure there is a filler value behind the top of the new space
+ // so that the GC does not confuse some unintialized/stale memory
+ // with the allocation memento of the object at the top
+ void EnsureFillerObjectAtTop();
+
+ // Ensure that we have swept all spaces in such a way that we can iterate
+ // over all objects. May cause a GC.
+ void MakeHeapIterable();
+
+ // Performs garbage collection operation.
+ // Returns whether there is a chance that another major GC could
+ // collect more garbage.
+ bool CollectGarbage(
+ GarbageCollector collector, const char* gc_reason,
+ const char* collector_reason,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ // Performs garbage collection
+ // Returns whether there is a chance another major GC could
+ // collect more garbage.
+ bool PerformGarbageCollection(
+ GarbageCollector collector,
+ const GCCallbackFlags gc_callback_flags = kNoGCCallbackFlags);
+
+ inline void UpdateOldSpaceLimits();
+
+ // Selects the proper allocation space depending on the given object
+ // size, pretenuring decision, and preferred old-space.
+ static AllocationSpace SelectSpace(int object_size,
+ AllocationSpace preferred_old_space,
+ PretenureFlag pretenure) {
+ DCHECK(preferred_old_space == OLD_POINTER_SPACE ||
+ preferred_old_space == OLD_DATA_SPACE);
+ if (object_size > Page::kMaxRegularHeapObjectSize) return LO_SPACE;
+ return (pretenure == TENURED) ? preferred_old_space : NEW_SPACE;
+ }
+
+ // Allocate an uninitialized object. The memory is non-executable if the
+ // hardware and OS allow. This is the single choke-point for allocations
+ // performed by the runtime and should not be bypassed (to extend this to
+ // inlined allocations, use the Heap::DisableInlineAllocation() support).
+ MUST_USE_RESULT inline AllocationResult AllocateRaw(
+ int size_in_bytes, AllocationSpace space, AllocationSpace retry_space);
+
+ // Allocates a heap object based on the map.
+ MUST_USE_RESULT AllocationResult
+ Allocate(Map* map, AllocationSpace space,
+ AllocationSite* allocation_site = NULL);
+
+ // Allocates a partial map for bootstrapping.
+ MUST_USE_RESULT AllocationResult
+ AllocatePartialMap(InstanceType instance_type, int instance_size);
+
+ // Initializes a JSObject based on its map.
+ void InitializeJSObjectFromMap(JSObject* obj, FixedArray* properties,
+ Map* map);
+ void InitializeAllocationMemento(AllocationMemento* memento,
+ AllocationSite* allocation_site);
+
+ // Allocate a block of memory in the given space (filled with a filler).
+ // Used as a fall-back for generated code when the space is full.
+ MUST_USE_RESULT AllocationResult
+ AllocateFillerObject(int size, bool double_align, AllocationSpace space);
+
+ // Allocate an uninitialized fixed array.
+ MUST_USE_RESULT AllocationResult
+ AllocateRawFixedArray(int length, PretenureFlag pretenure);
+
+ // Allocate an uninitialized fixed double array.
+ MUST_USE_RESULT AllocationResult
+ AllocateRawFixedDoubleArray(int length, PretenureFlag pretenure);
+
+ // Allocate an initialized fixed array with the given filler value.
+ MUST_USE_RESULT AllocationResult
+ AllocateFixedArrayWithFiller(int length, PretenureFlag pretenure,
+ Object* filler);
+
+ // Allocate and partially initializes a String. There are two String
+ // encodings: one-byte and two-byte. These functions allocate a string of
+ // the given length and set its map and length fields. The characters of
+ // the string are uninitialized.
+ MUST_USE_RESULT AllocationResult
+ AllocateRawOneByteString(int length, PretenureFlag pretenure);
+ MUST_USE_RESULT AllocationResult
+ AllocateRawTwoByteString(int length, PretenureFlag pretenure);
+
+ bool CreateInitialMaps();
+ void CreateInitialObjects();
+
+ // Allocates an internalized string in old space based on the character
+ // stream.
+ MUST_USE_RESULT inline AllocationResult AllocateInternalizedStringFromUtf8(
+ Vector<const char> str, int chars, uint32_t hash_field);
+
+ MUST_USE_RESULT inline AllocationResult AllocateOneByteInternalizedString(
+ Vector<const uint8_t> str, uint32_t hash_field);
+
+ MUST_USE_RESULT inline AllocationResult AllocateTwoByteInternalizedString(
+ Vector<const uc16> str, uint32_t hash_field);
+
+ template <bool is_one_byte, typename T>
+ MUST_USE_RESULT AllocationResult
+ AllocateInternalizedStringImpl(T t, int chars, uint32_t hash_field);
+
+ template <typename T>
+ MUST_USE_RESULT inline AllocationResult AllocateInternalizedStringImpl(
+ T t, int chars, uint32_t hash_field);
+
+ // Allocates an uninitialized fixed array. It must be filled by the caller.
+ MUST_USE_RESULT AllocationResult AllocateUninitializedFixedArray(int length);
+
+ // Make a copy of src and return it. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT inline AllocationResult CopyFixedArray(FixedArray* src);
+
+ // Make a copy of src, set the map, and return the copy. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT AllocationResult
+ CopyFixedArrayWithMap(FixedArray* src, Map* map);
+
+ // Make a copy of src and return it. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT inline AllocationResult CopyFixedDoubleArray(
+ FixedDoubleArray* src);
+
+ // Make a copy of src and return it. Returns
+ // Failure::RetryAfterGC(requested_bytes, space) if the allocation failed.
+ MUST_USE_RESULT inline AllocationResult CopyConstantPoolArray(
+ ConstantPoolArray* src);
+
+
+ // Computes a single character string where the character has code.
+ // A cache is used for one-byte (Latin1) codes.
+ MUST_USE_RESULT AllocationResult
+ LookupSingleCharacterStringFromCode(uint16_t code);
+
+ // Allocate a symbol in old space.
+ MUST_USE_RESULT AllocationResult AllocateSymbol();
+
+ // Make a copy of src, set the map, and return the copy.
+ MUST_USE_RESULT AllocationResult
+ CopyConstantPoolArrayWithMap(ConstantPoolArray* src, Map* map);
+
+ MUST_USE_RESULT AllocationResult AllocateConstantPoolArray(
+ const ConstantPoolArray::NumberOfEntries& small);
+
+ MUST_USE_RESULT AllocationResult AllocateExtendedConstantPoolArray(
+ const ConstantPoolArray::NumberOfEntries& small,
+ const ConstantPoolArray::NumberOfEntries& extended);
+
+ // Allocates an external array of the specified length and type.
+ MUST_USE_RESULT AllocationResult
+ AllocateExternalArray(int length, ExternalArrayType array_type,
+ void* external_pointer, PretenureFlag pretenure);
+
+ // Allocates a fixed typed array of the specified length and type.
+ MUST_USE_RESULT AllocationResult
+ AllocateFixedTypedArray(int length, ExternalArrayType array_type,
+ PretenureFlag pretenure);
+
+ // Make a copy of src and return it.
+ MUST_USE_RESULT AllocationResult CopyAndTenureFixedCOWArray(FixedArray* src);
+
+ // Make a copy of src, set the map, and return the copy.
+ MUST_USE_RESULT AllocationResult
+ CopyFixedDoubleArrayWithMap(FixedDoubleArray* src, Map* map);
+
+ // Allocates a fixed double array with uninitialized values. Returns
+ MUST_USE_RESULT AllocationResult AllocateUninitializedFixedDoubleArray(
+ int length, PretenureFlag pretenure = NOT_TENURED);
+
+ // These five Create*EntryStub functions are here and forced to not be inlined
+ // because of a gcc-4.4 bug that assigns wrong vtable entries.
+ NO_INLINE(void CreateJSEntryStub());
+ NO_INLINE(void CreateJSConstructEntryStub());
+
+ void CreateFixedStubs();
+
+ // Allocate empty fixed array.
+ MUST_USE_RESULT AllocationResult AllocateEmptyFixedArray();
+
+ // Allocate empty external array of given type.
+ MUST_USE_RESULT AllocationResult
+ AllocateEmptyExternalArray(ExternalArrayType array_type);
+
+ // Allocate empty fixed typed array of given type.
+ MUST_USE_RESULT AllocationResult
+ AllocateEmptyFixedTypedArray(ExternalArrayType array_type);
+
+ // Allocate empty constant pool array.
+ MUST_USE_RESULT AllocationResult AllocateEmptyConstantPoolArray();
+
+ // Allocate a tenured simple cell.
+ MUST_USE_RESULT AllocationResult AllocateCell(Object* value);
+
+ // Allocate a tenured JS global property cell initialized with the hole.
+ MUST_USE_RESULT AllocationResult AllocatePropertyCell();
+
+ // Allocates a new utility object in the old generation.
+ MUST_USE_RESULT AllocationResult AllocateStruct(InstanceType type);
+
+ // Allocates a new foreign object.
+ MUST_USE_RESULT AllocationResult
+ AllocateForeign(Address address, PretenureFlag pretenure = NOT_TENURED);
+
+ MUST_USE_RESULT AllocationResult
+ AllocateCode(int object_size, bool immovable);
+
+ MUST_USE_RESULT AllocationResult InternalizeStringWithKey(HashTableKey* key);
+
+ MUST_USE_RESULT AllocationResult InternalizeString(String* str);
+
+ // Performs a minor collection in new generation.
+ void Scavenge();
+
+ // Commits from space if it is uncommitted.
+ void EnsureFromSpaceIsCommitted();
+
+ // Uncommit unused semi space.
+ bool UncommitFromSpace() { return new_space_.UncommitFromSpace(); }
+
+ // Fill in bogus values in from space
+ void ZapFromSpace();
+
+ static String* UpdateNewSpaceReferenceInExternalStringTableEntry(
+ Heap* heap, Object** pointer);
+
+ Address DoScavenge(ObjectVisitor* scavenge_visitor, Address new_space_front);
+ static void ScavengeStoreBufferCallback(Heap* heap, MemoryChunk* page,
+ StoreBufferEvent event);
+
+ // Performs a major collection in the whole heap.
+ void MarkCompact();
+
+ // Code to be run before and after mark-compact.
+ void MarkCompactPrologue();
+
+ void ProcessNativeContexts(WeakObjectRetainer* retainer);
+ void ProcessArrayBuffers(WeakObjectRetainer* retainer);
+ void ProcessAllocationSites(WeakObjectRetainer* retainer);
+
+ // Deopts all code that contains allocation instruction which are tenured or
+ // not tenured. Moreover it clears the pretenuring allocation site statistics.
+ void ResetAllAllocationSitesDependentCode(PretenureFlag flag);
+
+ // Evaluates local pretenuring for the old space and calls
+ // ResetAllTenuredAllocationSitesDependentCode if too many objects died in
+ // the old space.
+ void EvaluateOldSpaceLocalPretenuring(uint64_t size_of_objects_before_gc);
+
+ // Called on heap tear-down.
+ void TearDownArrayBuffers();
+
+ // Record statistics before and after garbage collection.
+ void ReportStatisticsBeforeGC();
+ void ReportStatisticsAfterGC();
+
+ // Slow part of scavenge object.
+ static void ScavengeObjectSlow(HeapObject** p, HeapObject* object);
+
+ // Total RegExp code ever generated
+ double total_regexp_code_generated_;
+
+ GCTracer tracer_;
+
+ // Creates and installs the full-sized number string cache.
+ int FullSizeNumberStringCacheLength();
+ // Flush the number to string cache.
+ void FlushNumberStringCache();
+
+ // Sets used allocation sites entries to undefined.
+ void FlushAllocationSitesScratchpad();
+
+ // Initializes the allocation sites scratchpad with undefined values.
+ void InitializeAllocationSitesScratchpad();
+
+ // Adds an allocation site to the scratchpad if there is space left.
+ void AddAllocationSiteToScratchpad(AllocationSite* site,
+ ScratchpadSlotMode mode);
+
+ void UpdateSurvivalStatistics(int start_new_space_size);
+
+ static const int kYoungSurvivalRateHighThreshold = 90;
+ static const int kYoungSurvivalRateAllowedDeviation = 15;
+
+ static const int kOldSurvivalRateLowThreshold = 10;
+
+ int high_survival_rate_period_length_;
+ intptr_t promoted_objects_size_;
+ double promotion_rate_;
+ intptr_t semi_space_copied_object_size_;
+ double semi_space_copied_rate_;
+ int nodes_died_in_new_space_;
+ int nodes_copied_in_new_space_;
+ int nodes_promoted_;
+
+ // This is the pretenuring trigger for allocation sites that are in maybe
+ // tenure state. When we switched to the maximum new space size we deoptimize
+ // the code that belongs to the allocation site and derive the lifetime
+ // of the allocation site.
+ unsigned int maximum_size_scavenges_;
+
+ // TODO(hpayer): Allocation site pretenuring may make this method obsolete.
+ // Re-visit incremental marking heuristics.
+ bool IsHighSurvivalRate() { return high_survival_rate_period_length_ > 0; }
+
+ void SelectScavengingVisitorsTable();
+
+ void IdleMarkCompact(const char* message);
+
+ void AdvanceIdleIncrementalMarking(intptr_t step_size);
+
+ bool WorthActivatingIncrementalMarking();
+
+ void ClearObjectStats(bool clear_last_time_stats = false);
+
+ void set_weak_object_to_code_table(Object* value) {
+ DCHECK(!InNewSpace(value));
+ weak_object_to_code_table_ = value;
+ }
+
+ Object** weak_object_to_code_table_address() {
+ return &weak_object_to_code_table_;
+ }
+
+ inline void UpdateAllocationsHash(HeapObject* object);
+ inline void UpdateAllocationsHash(uint32_t value);
+ inline void PrintAlloctionsHash();
+
+ static const int kInitialStringTableSize = 2048;
+ static const int kInitialEvalCacheSize = 64;
+ static const int kInitialNumberStringCacheSize = 256;
+
+ // Object counts and used memory by InstanceType
+ size_t object_counts_[OBJECT_STATS_COUNT];
+ size_t object_counts_last_time_[OBJECT_STATS_COUNT];
+ size_t object_sizes_[OBJECT_STATS_COUNT];
+ size_t object_sizes_last_time_[OBJECT_STATS_COUNT];
+
+ // Maximum GC pause.
+ double max_gc_pause_;
+
+ // Total time spent in GC.
+ double total_gc_time_ms_;
+
+ // Maximum size of objects alive after GC.
+ intptr_t max_alive_after_gc_;
+
+ // Minimal interval between two subsequent collections.
+ double min_in_mutator_;
+
+ // Cumulative GC time spent in marking
+ double marking_time_;
+
+ // Cumulative GC time spent in sweeping
+ double sweeping_time_;
+
+ MarkCompactCollector mark_compact_collector_;
+
+ StoreBuffer store_buffer_;
+
+ Marking marking_;
+
+ IncrementalMarking incremental_marking_;
+
+ GCIdleTimeHandler gc_idle_time_handler_;
+ unsigned int gc_count_at_last_idle_gc_;
+
+ // These two counters are monotomically increasing and never reset.
+ size_t full_codegen_bytes_generated_;
+ size_t crankshaft_codegen_bytes_generated_;
+
+ // If the --deopt_every_n_garbage_collections flag is set to a positive value,
+ // this variable holds the number of garbage collections since the last
+ // deoptimization triggered by garbage collection.
+ int gcs_since_last_deopt_;
+
+#ifdef VERIFY_HEAP
+ int no_weak_object_verification_scope_depth_;
+#endif
+
+ static const int kAllocationSiteScratchpadSize = 256;
+ int allocation_sites_scratchpad_length_;
+
+ static const int kMaxMarkCompactsInIdleRound = 7;
+ static const int kIdleScavengeThreshold = 5;
+
+ // Shared state read by the scavenge collector and set by ScavengeObject.
+ PromotionQueue promotion_queue_;
+
+ // Flag is set when the heap has been configured. The heap can be repeatedly
+ // configured through the API until it is set up.
+ bool configured_;
+
+ ExternalStringTable external_string_table_;
+
+ VisitorDispatchTable<ScavengingCallback> scavenging_visitors_table_;
+
+ MemoryChunk* chunks_queued_for_free_;
+
+ base::Mutex relocation_mutex_;
+
+ int gc_callbacks_depth_;
+
+ friend class AlwaysAllocateScope;
+ friend class Factory;
+ friend class GCCallbacksScope;
+ friend class GCTracer;
+ friend class HeapIterator;
+ friend class Isolate;
+ friend class MarkCompactCollector;
+ friend class MarkCompactMarkingVisitor;
+ friend class MapCompact;
+#ifdef VERIFY_HEAP
+ friend class NoWeakObjectVerificationScope;
+#endif
+ friend class Page;
+
+ DISALLOW_COPY_AND_ASSIGN(Heap);
+};
+
+
+class HeapStats {
+ public:
+ static const int kStartMarker = 0xDECADE00;
+ static const int kEndMarker = 0xDECADE01;
+
+ int* start_marker; // 0
+ int* new_space_size; // 1
+ int* new_space_capacity; // 2
+ intptr_t* old_pointer_space_size; // 3
+ intptr_t* old_pointer_space_capacity; // 4
+ intptr_t* old_data_space_size; // 5
+ intptr_t* old_data_space_capacity; // 6
+ intptr_t* code_space_size; // 7
+ intptr_t* code_space_capacity; // 8
+ intptr_t* map_space_size; // 9
+ intptr_t* map_space_capacity; // 10
+ intptr_t* cell_space_size; // 11
+ intptr_t* cell_space_capacity; // 12
+ intptr_t* lo_space_size; // 13
+ int* global_handle_count; // 14
+ int* weak_global_handle_count; // 15
+ int* pending_global_handle_count; // 16
+ int* near_death_global_handle_count; // 17
+ int* free_global_handle_count; // 18
+ intptr_t* memory_allocator_size; // 19
+ intptr_t* memory_allocator_capacity; // 20
+ int* objects_per_type; // 21
+ int* size_per_type; // 22
+ int* os_error; // 23
+ int* end_marker; // 24
+ intptr_t* property_cell_space_size; // 25
+ intptr_t* property_cell_space_capacity; // 26
+};
+
+
+class AlwaysAllocateScope {
+ public:
+ explicit inline AlwaysAllocateScope(Isolate* isolate);
+ inline ~AlwaysAllocateScope();
+
+ private:
+ // Implicitly disable artificial allocation failures.
+ Heap* heap_;
+ DisallowAllocationFailure daf_;
+};
+
+
+#ifdef VERIFY_HEAP
+class NoWeakObjectVerificationScope {
+ public:
+ inline NoWeakObjectVerificationScope();
+ inline ~NoWeakObjectVerificationScope();
+};
+#endif
+
+
+class GCCallbacksScope {
+ public:
+ explicit inline GCCallbacksScope(Heap* heap);
+ inline ~GCCallbacksScope();
+
+ inline bool CheckReenter();
+
+ private:
+ Heap* heap_;
+};
+
+
+// Visitor class to verify interior pointers in spaces that do not contain
+// or care about intergenerational references. All heap object pointers have to
+// point into the heap to a location that has a map pointer at its first word.
+// Caveat: Heap::Contains is an approximation because it can return true for
+// objects in a heap space but above the allocation pointer.
+class VerifyPointersVisitor : public ObjectVisitor {
+ public:
+ inline void VisitPointers(Object** start, Object** end);
+};
+
+
+// Verify that all objects are Smis.
+class VerifySmisVisitor : public ObjectVisitor {
+ public:
+ inline void VisitPointers(Object** start, Object** end);
+};
+
+
+// Space iterator for iterating over all spaces of the heap. Returns each space
+// in turn, and null when it is done.
+class AllSpaces BASE_EMBEDDED {
+ public:
+ explicit AllSpaces(Heap* heap) : heap_(heap), counter_(FIRST_SPACE) {}
+ Space* next();
+
+ private:
+ Heap* heap_;
+ int counter_;
+};
+
+
+// Space iterator for iterating over all old spaces of the heap: Old pointer
+// space, old data space and code space. Returns each space in turn, and null
+// when it is done.
+class OldSpaces BASE_EMBEDDED {
+ public:
+ explicit OldSpaces(Heap* heap) : heap_(heap), counter_(OLD_POINTER_SPACE) {}
+ OldSpace* next();
+
+ private:
+ Heap* heap_;
+ int counter_;
+};
+
+
+// Space iterator for iterating over all the paged spaces of the heap: Map
+// space, old pointer space, old data space, code space and cell space. Returns
+// each space in turn, and null when it is done.
+class PagedSpaces BASE_EMBEDDED {
+ public:
+ explicit PagedSpaces(Heap* heap) : heap_(heap), counter_(OLD_POINTER_SPACE) {}
+ PagedSpace* next();
+
+ private:
+ Heap* heap_;
+ int counter_;
+};
+
+
+// Space iterator for iterating over all spaces of the heap.
+// For each space an object iterator is provided. The deallocation of the
+// returned object iterators is handled by the space iterator.
+class SpaceIterator : public Malloced {
+ public:
+ explicit SpaceIterator(Heap* heap);
+ SpaceIterator(Heap* heap, HeapObjectCallback size_func);
+ virtual ~SpaceIterator();
+
+ bool has_next();
+ ObjectIterator* next();
+
+ private:
+ ObjectIterator* CreateIterator();
+
+ Heap* heap_;
+ int current_space_; // from enum AllocationSpace.
+ ObjectIterator* iterator_; // object iterator for the current space.
+ HeapObjectCallback size_func_;
+};
+
+
+// A HeapIterator provides iteration over the whole heap. It
+// aggregates the specific iterators for the different spaces as
+// these can only iterate over one space only.
+//
+// HeapIterator ensures there is no allocation during its lifetime
+// (using an embedded DisallowHeapAllocation instance).
+//
+// HeapIterator can skip free list nodes (that is, de-allocated heap
+// objects that still remain in the heap). As implementation of free
+// nodes filtering uses GC marks, it can't be used during MS/MC GC
+// phases. Also, it is forbidden to interrupt iteration in this mode,
+// as this will leave heap objects marked (and thus, unusable).
+class HeapObjectsFilter;
+
+class HeapIterator BASE_EMBEDDED {
+ public:
+ enum HeapObjectsFiltering { kNoFiltering, kFilterUnreachable };
+
+ explicit HeapIterator(Heap* heap);
+ HeapIterator(Heap* heap, HeapObjectsFiltering filtering);
+ ~HeapIterator();
+
+ HeapObject* next();
+ void reset();
+
+ private:
+ struct MakeHeapIterableHelper {
+ explicit MakeHeapIterableHelper(Heap* heap) { heap->MakeHeapIterable(); }
+ };
+
+ // Perform the initialization.
+ void Init();
+ // Perform all necessary shutdown (destruction) work.
+ void Shutdown();
+ HeapObject* NextObject();
+
+ MakeHeapIterableHelper make_heap_iterable_helper_;
+ DisallowHeapAllocation no_heap_allocation_;
+ Heap* heap_;
+ HeapObjectsFiltering filtering_;
+ HeapObjectsFilter* filter_;
+ // Space iterator for iterating all the spaces.
+ SpaceIterator* space_iterator_;
+ // Object iterator for the space currently being iterated.
+ ObjectIterator* object_iterator_;
+};
+
+
+// Cache for mapping (map, property name) into field offset.
+// Cleared at startup and prior to mark sweep collection.
+class KeyedLookupCache {
+ public:
+ // Lookup field offset for (map, name). If absent, -1 is returned.
+ int Lookup(Handle<Map> map, Handle<Name> name);
+
+ // Update an element in the cache.
+ void Update(Handle<Map> map, Handle<Name> name, int field_offset);
+
+ // Clear the cache.
+ void Clear();
+
+ static const int kLength = 256;
+ static const int kCapacityMask = kLength - 1;
+ static const int kMapHashShift = 5;
+ static const int kHashMask = -4; // Zero the last two bits.
+ static const int kEntriesPerBucket = 4;
+ static const int kEntryLength = 2;
+ static const int kMapIndex = 0;
+ static const int kKeyIndex = 1;
+ static const int kNotFound = -1;
+
+ // kEntriesPerBucket should be a power of 2.
+ STATIC_ASSERT((kEntriesPerBucket & (kEntriesPerBucket - 1)) == 0);
+ STATIC_ASSERT(kEntriesPerBucket == -kHashMask);
+
+ private:
+ KeyedLookupCache() {
+ for (int i = 0; i < kLength; ++i) {
+ keys_[i].map = NULL;
+ keys_[i].name = NULL;
+ field_offsets_[i] = kNotFound;
+ }
+ }
+
+ static inline int Hash(Handle<Map> map, Handle<Name> name);
+
+ // Get the address of the keys and field_offsets arrays. Used in
+ // generated code to perform cache lookups.
+ Address keys_address() { return reinterpret_cast<Address>(&keys_); }
+
+ Address field_offsets_address() {
+ return reinterpret_cast<Address>(&field_offsets_);
+ }
+
+ struct Key {
+ Map* map;
+ Name* name;
+ };
+
+ Key keys_[kLength];
+ int field_offsets_[kLength];
+
+ friend class ExternalReference;
+ friend class Isolate;
+ DISALLOW_COPY_AND_ASSIGN(KeyedLookupCache);
+};
+
+
+// Cache for mapping (map, property name) into descriptor index.
+// The cache contains both positive and negative results.
+// Descriptor index equals kNotFound means the property is absent.
+// Cleared at startup and prior to any gc.
+class DescriptorLookupCache {
+ public:
+ // Lookup descriptor index for (map, name).
+ // If absent, kAbsent is returned.
+ int Lookup(Map* source, Name* name) {
+ if (!name->IsUniqueName()) return kAbsent;
+ int index = Hash(source, name);
+ Key& key = keys_[index];
+ if ((key.source == source) && (key.name == name)) return results_[index];
+ return kAbsent;
+ }
+
+ // Update an element in the cache.
+ void Update(Map* source, Name* name, int result) {
+ DCHECK(result != kAbsent);
+ if (name->IsUniqueName()) {
+ int index = Hash(source, name);
+ Key& key = keys_[index];
+ key.source = source;
+ key.name = name;
+ results_[index] = result;
+ }
+ }
+
+ // Clear the cache.
+ void Clear();
+
+ static const int kAbsent = -2;
+
+ private:
+ DescriptorLookupCache() {
+ for (int i = 0; i < kLength; ++i) {
+ keys_[i].source = NULL;
+ keys_[i].name = NULL;
+ results_[i] = kAbsent;
+ }
+ }
+
+ static int Hash(Object* source, Name* name) {
+ // Uses only lower 32 bits if pointers are larger.
+ uint32_t source_hash =
+ static_cast<uint32_t>(reinterpret_cast<uintptr_t>(source)) >>
+ kPointerSizeLog2;
+ uint32_t name_hash =
+ static_cast<uint32_t>(reinterpret_cast<uintptr_t>(name)) >>
+ kPointerSizeLog2;
+ return (source_hash ^ name_hash) % kLength;
+ }
+
+ static const int kLength = 64;
+ struct Key {
+ Map* source;
+ Name* name;
+ };
+
+ Key keys_[kLength];
+ int results_[kLength];
+
+ friend class Isolate;
+ DISALLOW_COPY_AND_ASSIGN(DescriptorLookupCache);
+};
+
+
+class RegExpResultsCache {
+ public:
+ enum ResultsCacheType { REGEXP_MULTIPLE_INDICES, STRING_SPLIT_SUBSTRINGS };
+
+ // Attempt to retrieve a cached result. On failure, 0 is returned as a Smi.
+ // On success, the returned result is guaranteed to be a COW-array.
+ static Object* Lookup(Heap* heap, String* key_string, Object* key_pattern,
+ ResultsCacheType type);
+ // Attempt to add value_array to the cache specified by type. On success,
+ // value_array is turned into a COW-array.
+ static void Enter(Isolate* isolate, Handle<String> key_string,
+ Handle<Object> key_pattern, Handle<FixedArray> value_array,
+ ResultsCacheType type);
+ static void Clear(FixedArray* cache);
+ static const int kRegExpResultsCacheSize = 0x100;
+
+ private:
+ static const int kArrayEntriesPerCacheEntry = 4;
+ static const int kStringOffset = 0;
+ static const int kPatternOffset = 1;
+ static const int kArrayOffset = 2;
+};
+
+
+// Abstract base class for checking whether a weak object should be retained.
+class WeakObjectRetainer {
+ public:
+ virtual ~WeakObjectRetainer() {}
+
+ // Return whether this object should be retained. If NULL is returned the
+ // object has no references. Otherwise the address of the retained object
+ // should be returned as in some GC situations the object has been moved.
+ virtual Object* RetainAs(Object* object) = 0;
+};
+
+
+// Intrusive object marking uses least significant bit of
+// heap object's map word to mark objects.
+// Normally all map words have least significant bit set
+// because they contain tagged map pointer.
+// If the bit is not set object is marked.
+// All objects should be unmarked before resuming
+// JavaScript execution.
+class IntrusiveMarking {
+ public:
+ static bool IsMarked(HeapObject* object) {
+ return (object->map_word().ToRawValue() & kNotMarkedBit) == 0;
+ }
+
+ static void ClearMark(HeapObject* object) {
+ uintptr_t map_word = object->map_word().ToRawValue();
+ object->set_map_word(MapWord::FromRawValue(map_word | kNotMarkedBit));
+ DCHECK(!IsMarked(object));
+ }
+
+ static void SetMark(HeapObject* object) {
+ uintptr_t map_word = object->map_word().ToRawValue();
+ object->set_map_word(MapWord::FromRawValue(map_word & ~kNotMarkedBit));
+ DCHECK(IsMarked(object));
+ }
+
+ static Map* MapOfMarkedObject(HeapObject* object) {
+ uintptr_t map_word = object->map_word().ToRawValue();
+ return MapWord::FromRawValue(map_word | kNotMarkedBit).ToMap();
+ }
+
+ static int SizeOfMarkedObject(HeapObject* object) {
+ return object->SizeFromMap(MapOfMarkedObject(object));
+ }
+
+ private:
+ static const uintptr_t kNotMarkedBit = 0x1;
+ STATIC_ASSERT((kHeapObjectTag & kNotMarkedBit) != 0); // NOLINT
+};
+
+
+#ifdef DEBUG
+// Helper class for tracing paths to a search target Object from all roots.
+// The TracePathFrom() method can be used to trace paths from a specific
+// object to the search target object.
+class PathTracer : public ObjectVisitor {
+ public:
+ enum WhatToFind {
+ FIND_ALL, // Will find all matches.
+ FIND_FIRST // Will stop the search after first match.
+ };
+
+ // Tags 0, 1, and 3 are used. Use 2 for marking visited HeapObject.
+ static const int kMarkTag = 2;
+
+ // For the WhatToFind arg, if FIND_FIRST is specified, tracing will stop
+ // after the first match. If FIND_ALL is specified, then tracing will be
+ // done for all matches.
+ PathTracer(Object* search_target, WhatToFind what_to_find,
+ VisitMode visit_mode)
+ : search_target_(search_target),
+ found_target_(false),
+ found_target_in_trace_(false),
+ what_to_find_(what_to_find),
+ visit_mode_(visit_mode),
+ object_stack_(20),
+ no_allocation() {}
+
+ virtual void VisitPointers(Object** start, Object** end);
+
+ void Reset();
+ void TracePathFrom(Object** root);
+
+ bool found() const { return found_target_; }
+
+ static Object* const kAnyGlobalObject;
+
+ protected:
+ class MarkVisitor;
+ class UnmarkVisitor;
+
+ void MarkRecursively(Object** p, MarkVisitor* mark_visitor);
+ void UnmarkRecursively(Object** p, UnmarkVisitor* unmark_visitor);
+ virtual void ProcessResults();
+
+ Object* search_target_;
+ bool found_target_;
+ bool found_target_in_trace_;
+ WhatToFind what_to_find_;
+ VisitMode visit_mode_;
+ List<Object*> object_stack_;
+
+ DisallowHeapAllocation no_allocation; // i.e. no gc allowed.
+
+ private:
+ DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
+};
+#endif // DEBUG
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_HEAP_H_
diff --git a/src/heap/incremental-marking-inl.h b/src/heap/incremental-marking-inl.h
new file mode 100644
index 0000000..5258c5c
--- /dev/null
+++ b/src/heap/incremental-marking-inl.h
@@ -0,0 +1,117 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_INCREMENTAL_MARKING_INL_H_
+#define V8_HEAP_INCREMENTAL_MARKING_INL_H_
+
+#include "src/heap/incremental-marking.h"
+
+namespace v8 {
+namespace internal {
+
+
+bool IncrementalMarking::BaseRecordWrite(HeapObject* obj, Object** slot,
+ Object* value) {
+ HeapObject* value_heap_obj = HeapObject::cast(value);
+ MarkBit value_bit = Marking::MarkBitFrom(value_heap_obj);
+ if (Marking::IsWhite(value_bit)) {
+ MarkBit obj_bit = Marking::MarkBitFrom(obj);
+ if (Marking::IsBlack(obj_bit)) {
+ MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
+ if (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR)) {
+ if (chunk->IsLeftOfProgressBar(slot)) {
+ WhiteToGreyAndPush(value_heap_obj, value_bit);
+ RestartIfNotMarking();
+ } else {
+ return false;
+ }
+ } else {
+ BlackToGreyAndUnshift(obj, obj_bit);
+ RestartIfNotMarking();
+ return false;
+ }
+ } else {
+ return false;
+ }
+ }
+ if (!is_compacting_) return false;
+ MarkBit obj_bit = Marking::MarkBitFrom(obj);
+ return Marking::IsBlack(obj_bit);
+}
+
+
+void IncrementalMarking::RecordWrite(HeapObject* obj, Object** slot,
+ Object* value) {
+ if (IsMarking() && value->IsHeapObject()) {
+ RecordWriteSlow(obj, slot, value);
+ }
+}
+
+
+void IncrementalMarking::RecordWriteOfCodeEntry(JSFunction* host, Object** slot,
+ Code* value) {
+ if (IsMarking()) RecordWriteOfCodeEntrySlow(host, slot, value);
+}
+
+
+void IncrementalMarking::RecordWriteIntoCode(HeapObject* obj, RelocInfo* rinfo,
+ Object* value) {
+ if (IsMarking() && value->IsHeapObject()) {
+ RecordWriteIntoCodeSlow(obj, rinfo, value);
+ }
+}
+
+
+void IncrementalMarking::RecordWrites(HeapObject* obj) {
+ if (IsMarking()) {
+ MarkBit obj_bit = Marking::MarkBitFrom(obj);
+ if (Marking::IsBlack(obj_bit)) {
+ MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
+ if (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR)) {
+ chunk->set_progress_bar(0);
+ }
+ BlackToGreyAndUnshift(obj, obj_bit);
+ RestartIfNotMarking();
+ }
+ }
+}
+
+
+void IncrementalMarking::BlackToGreyAndUnshift(HeapObject* obj,
+ MarkBit mark_bit) {
+ DCHECK(Marking::MarkBitFrom(obj) == mark_bit);
+ DCHECK(obj->Size() >= 2 * kPointerSize);
+ DCHECK(IsMarking());
+ Marking::BlackToGrey(mark_bit);
+ int obj_size = obj->Size();
+ MemoryChunk::IncrementLiveBytesFromGC(obj->address(), -obj_size);
+ bytes_scanned_ -= obj_size;
+ int64_t old_bytes_rescanned = bytes_rescanned_;
+ bytes_rescanned_ = old_bytes_rescanned + obj_size;
+ if ((bytes_rescanned_ >> 20) != (old_bytes_rescanned >> 20)) {
+ if (bytes_rescanned_ > 2 * heap_->PromotedSpaceSizeOfObjects()) {
+ // If we have queued twice the heap size for rescanning then we are
+ // going around in circles, scanning the same objects again and again
+ // as the program mutates the heap faster than we can incrementally
+ // trace it. In this case we switch to non-incremental marking in
+ // order to finish off this marking phase.
+ if (FLAG_trace_gc) {
+ PrintPID("Hurrying incremental marking because of lack of progress\n");
+ }
+ marking_speed_ = kMaxMarkingSpeed;
+ }
+ }
+
+ marking_deque_.UnshiftGrey(obj);
+}
+
+
+void IncrementalMarking::WhiteToGreyAndPush(HeapObject* obj, MarkBit mark_bit) {
+ Marking::WhiteToGrey(mark_bit);
+ marking_deque_.PushGrey(obj);
+}
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_INCREMENTAL_MARKING_INL_H_
diff --git a/src/heap/incremental-marking.cc b/src/heap/incremental-marking.cc
new file mode 100644
index 0000000..d72423a
--- /dev/null
+++ b/src/heap/incremental-marking.cc
@@ -0,0 +1,982 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#include "src/heap/incremental-marking.h"
+
+#include "src/code-stubs.h"
+#include "src/compilation-cache.h"
+#include "src/conversions.h"
+#include "src/heap/objects-visiting.h"
+#include "src/heap/objects-visiting-inl.h"
+
+namespace v8 {
+namespace internal {
+
+
+IncrementalMarking::IncrementalMarking(Heap* heap)
+ : heap_(heap),
+ state_(STOPPED),
+ marking_deque_memory_(NULL),
+ marking_deque_memory_committed_(false),
+ steps_count_(0),
+ old_generation_space_available_at_start_of_incremental_(0),
+ old_generation_space_used_at_start_of_incremental_(0),
+ should_hurry_(false),
+ marking_speed_(0),
+ allocated_(0),
+ no_marking_scope_depth_(0),
+ unscanned_bytes_of_large_object_(0) {}
+
+
+void IncrementalMarking::TearDown() { delete marking_deque_memory_; }
+
+
+void IncrementalMarking::RecordWriteSlow(HeapObject* obj, Object** slot,
+ Object* value) {
+ if (BaseRecordWrite(obj, slot, value) && slot != NULL) {
+ MarkBit obj_bit = Marking::MarkBitFrom(obj);
+ if (Marking::IsBlack(obj_bit)) {
+ // Object is not going to be rescanned we need to record the slot.
+ heap_->mark_compact_collector()->RecordSlot(HeapObject::RawField(obj, 0),
+ slot, value);
+ }
+ }
+}
+
+
+void IncrementalMarking::RecordWriteFromCode(HeapObject* obj, Object** slot,
+ Isolate* isolate) {
+ DCHECK(obj->IsHeapObject());
+ IncrementalMarking* marking = isolate->heap()->incremental_marking();
+
+ MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
+ int counter = chunk->write_barrier_counter();
+ if (counter < (MemoryChunk::kWriteBarrierCounterGranularity / 2)) {
+ marking->write_barriers_invoked_since_last_step_ +=
+ MemoryChunk::kWriteBarrierCounterGranularity -
+ chunk->write_barrier_counter();
+ chunk->set_write_barrier_counter(
+ MemoryChunk::kWriteBarrierCounterGranularity);
+ }
+
+ marking->RecordWrite(obj, slot, *slot);
+}
+
+
+void IncrementalMarking::RecordCodeTargetPatch(Code* host, Address pc,
+ HeapObject* value) {
+ if (IsMarking()) {
+ RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host);
+ RecordWriteIntoCode(host, &rinfo, value);
+ }
+}
+
+
+void IncrementalMarking::RecordCodeTargetPatch(Address pc, HeapObject* value) {
+ if (IsMarking()) {
+ Code* host = heap_->isolate()
+ ->inner_pointer_to_code_cache()
+ ->GcSafeFindCodeForInnerPointer(pc);
+ RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host);
+ RecordWriteIntoCode(host, &rinfo, value);
+ }
+}
+
+
+void IncrementalMarking::RecordWriteOfCodeEntrySlow(JSFunction* host,
+ Object** slot,
+ Code* value) {
+ if (BaseRecordWrite(host, slot, value)) {
+ DCHECK(slot != NULL);
+ heap_->mark_compact_collector()->RecordCodeEntrySlot(
+ reinterpret_cast<Address>(slot), value);
+ }
+}
+
+
+void IncrementalMarking::RecordWriteIntoCodeSlow(HeapObject* obj,
+ RelocInfo* rinfo,
+ Object* value) {
+ MarkBit value_bit = Marking::MarkBitFrom(HeapObject::cast(value));
+ if (Marking::IsWhite(value_bit)) {
+ MarkBit obj_bit = Marking::MarkBitFrom(obj);
+ if (Marking::IsBlack(obj_bit)) {
+ BlackToGreyAndUnshift(obj, obj_bit);
+ RestartIfNotMarking();
+ }
+ // Object is either grey or white. It will be scanned if survives.
+ return;
+ }
+
+ if (is_compacting_) {
+ MarkBit obj_bit = Marking::MarkBitFrom(obj);
+ if (Marking::IsBlack(obj_bit)) {
+ // Object is not going to be rescanned. We need to record the slot.
+ heap_->mark_compact_collector()->RecordRelocSlot(rinfo,
+ Code::cast(value));
+ }
+ }
+}
+
+
+static void MarkObjectGreyDoNotEnqueue(Object* obj) {
+ if (obj->IsHeapObject()) {
+ HeapObject* heap_obj = HeapObject::cast(obj);
+ MarkBit mark_bit = Marking::MarkBitFrom(HeapObject::cast(obj));
+ if (Marking::IsBlack(mark_bit)) {
+ MemoryChunk::IncrementLiveBytesFromGC(heap_obj->address(),
+ -heap_obj->Size());
+ }
+ Marking::AnyToGrey(mark_bit);
+ }
+}
+
+
+static inline void MarkBlackOrKeepGrey(HeapObject* heap_object,
+ MarkBit mark_bit, int size) {
+ DCHECK(!Marking::IsImpossible(mark_bit));
+ if (mark_bit.Get()) return;
+ mark_bit.Set();
+ MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(), size);
+ DCHECK(Marking::IsBlack(mark_bit));
+}
+
+
+static inline void MarkBlackOrKeepBlack(HeapObject* heap_object,
+ MarkBit mark_bit, int size) {
+ DCHECK(!Marking::IsImpossible(mark_bit));
+ if (Marking::IsBlack(mark_bit)) return;
+ Marking::MarkBlack(mark_bit);
+ MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(), size);
+ DCHECK(Marking::IsBlack(mark_bit));
+}
+
+
+class IncrementalMarkingMarkingVisitor
+ : public StaticMarkingVisitor<IncrementalMarkingMarkingVisitor> {
+ public:
+ static void Initialize() {
+ StaticMarkingVisitor<IncrementalMarkingMarkingVisitor>::Initialize();
+ table_.Register(kVisitFixedArray, &VisitFixedArrayIncremental);
+ table_.Register(kVisitNativeContext, &VisitNativeContextIncremental);
+ table_.Register(kVisitJSRegExp, &VisitJSRegExp);
+ }
+
+ static const int kProgressBarScanningChunk = 32 * 1024;
+
+ static void VisitFixedArrayIncremental(Map* map, HeapObject* object) {
+ MemoryChunk* chunk = MemoryChunk::FromAddress(object->address());
+ // TODO(mstarzinger): Move setting of the flag to the allocation site of
+ // the array. The visitor should just check the flag.
+ if (FLAG_use_marking_progress_bar &&
+ chunk->owner()->identity() == LO_SPACE) {
+ chunk->SetFlag(MemoryChunk::HAS_PROGRESS_BAR);
+ }
+ if (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR)) {
+ Heap* heap = map->GetHeap();
+ // When using a progress bar for large fixed arrays, scan only a chunk of
+ // the array and try to push it onto the marking deque again until it is
+ // fully scanned. Fall back to scanning it through to the end in case this
+ // fails because of a full deque.
+ int object_size = FixedArray::BodyDescriptor::SizeOf(map, object);
+ int start_offset =
+ Max(FixedArray::BodyDescriptor::kStartOffset, chunk->progress_bar());
+ int end_offset =
+ Min(object_size, start_offset + kProgressBarScanningChunk);
+ int already_scanned_offset = start_offset;
+ bool scan_until_end = false;
+ do {
+ VisitPointersWithAnchor(heap, HeapObject::RawField(object, 0),
+ HeapObject::RawField(object, start_offset),
+ HeapObject::RawField(object, end_offset));
+ start_offset = end_offset;
+ end_offset = Min(object_size, end_offset + kProgressBarScanningChunk);
+ scan_until_end = heap->incremental_marking()->marking_deque()->IsFull();
+ } while (scan_until_end && start_offset < object_size);
+ chunk->set_progress_bar(start_offset);
+ if (start_offset < object_size) {
+ heap->incremental_marking()->marking_deque()->UnshiftGrey(object);
+ heap->incremental_marking()->NotifyIncompleteScanOfObject(
+ object_size - (start_offset - already_scanned_offset));
+ }
+ } else {
+ FixedArrayVisitor::Visit(map, object);
+ }
+ }
+
+ static void VisitNativeContextIncremental(Map* map, HeapObject* object) {
+ Context* context = Context::cast(object);
+
+ // We will mark cache black with a separate pass when we finish marking.
+ // Note that GC can happen when the context is not fully initialized,
+ // so the cache can be undefined.
+ Object* cache = context->get(Context::NORMALIZED_MAP_CACHE_INDEX);
+ if (!cache->IsUndefined()) {
+ MarkObjectGreyDoNotEnqueue(cache);
+ }
+ VisitNativeContext(map, context);
+ }
+
+ INLINE(static void VisitPointer(Heap* heap, Object** p)) {
+ Object* obj = *p;
+ if (obj->IsHeapObject()) {
+ heap->mark_compact_collector()->RecordSlot(p, p, obj);
+ MarkObject(heap, obj);
+ }
+ }
+
+ INLINE(static void VisitPointers(Heap* heap, Object** start, Object** end)) {
+ for (Object** p = start; p < end; p++) {
+ Object* obj = *p;
+ if (obj->IsHeapObject()) {
+ heap->mark_compact_collector()->RecordSlot(start, p, obj);
+ MarkObject(heap, obj);
+ }
+ }
+ }
+
+ INLINE(static void VisitPointersWithAnchor(Heap* heap, Object** anchor,
+ Object** start, Object** end)) {
+ for (Object** p = start; p < end; p++) {
+ Object* obj = *p;
+ if (obj->IsHeapObject()) {
+ heap->mark_compact_collector()->RecordSlot(anchor, p, obj);
+ MarkObject(heap, obj);
+ }
+ }
+ }
+
+ // Marks the object grey and pushes it on the marking stack.
+ INLINE(static void MarkObject(Heap* heap, Object* obj)) {
+ HeapObject* heap_object = HeapObject::cast(obj);
+ MarkBit mark_bit = Marking::MarkBitFrom(heap_object);
+ if (mark_bit.data_only()) {
+ MarkBlackOrKeepGrey(heap_object, mark_bit, heap_object->Size());
+ } else if (Marking::IsWhite(mark_bit)) {
+ heap->incremental_marking()->WhiteToGreyAndPush(heap_object, mark_bit);
+ }
+ }
+
+ // Marks the object black without pushing it on the marking stack.
+ // Returns true if object needed marking and false otherwise.
+ INLINE(static bool MarkObjectWithoutPush(Heap* heap, Object* obj)) {
+ HeapObject* heap_object = HeapObject::cast(obj);
+ MarkBit mark_bit = Marking::MarkBitFrom(heap_object);
+ if (Marking::IsWhite(mark_bit)) {
+ mark_bit.Set();
+ MemoryChunk::IncrementLiveBytesFromGC(heap_object->address(),
+ heap_object->Size());
+ return true;
+ }
+ return false;
+ }
+};
+
+
+class IncrementalMarkingRootMarkingVisitor : public ObjectVisitor {
+ public:
+ explicit IncrementalMarkingRootMarkingVisitor(
+ IncrementalMarking* incremental_marking)
+ : incremental_marking_(incremental_marking) {}
+
+ void VisitPointer(Object** p) { MarkObjectByPointer(p); }
+
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++) MarkObjectByPointer(p);
+ }
+
+ private:
+ void MarkObjectByPointer(Object** p) {
+ Object* obj = *p;
+ if (!obj->IsHeapObject()) return;
+
+ HeapObject* heap_object = HeapObject::cast(obj);
+ MarkBit mark_bit = Marking::MarkBitFrom(heap_object);
+ if (mark_bit.data_only()) {
+ MarkBlackOrKeepGrey(heap_object, mark_bit, heap_object->Size());
+ } else {
+ if (Marking::IsWhite(mark_bit)) {
+ incremental_marking_->WhiteToGreyAndPush(heap_object, mark_bit);
+ }
+ }
+ }
+
+ IncrementalMarking* incremental_marking_;
+};
+
+
+void IncrementalMarking::Initialize() {
+ IncrementalMarkingMarkingVisitor::Initialize();
+}
+
+
+void IncrementalMarking::SetOldSpacePageFlags(MemoryChunk* chunk,
+ bool is_marking,
+ bool is_compacting) {
+ if (is_marking) {
+ chunk->SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING);
+ chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING);
+
+ // It's difficult to filter out slots recorded for large objects.
+ if (chunk->owner()->identity() == LO_SPACE &&
+ chunk->size() > static_cast<size_t>(Page::kPageSize) && is_compacting) {
+ chunk->SetFlag(MemoryChunk::RESCAN_ON_EVACUATION);
+ }
+ } else if (chunk->owner()->identity() == CELL_SPACE ||
+ chunk->owner()->identity() == PROPERTY_CELL_SPACE ||
+ chunk->scan_on_scavenge()) {
+ chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING);
+ chunk->ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING);
+ } else {
+ chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING);
+ chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING);
+ }
+}
+
+
+void IncrementalMarking::SetNewSpacePageFlags(NewSpacePage* chunk,
+ bool is_marking) {
+ chunk->SetFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING);
+ if (is_marking) {
+ chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING);
+ } else {
+ chunk->ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING);
+ }
+ chunk->SetFlag(MemoryChunk::SCAN_ON_SCAVENGE);
+}
+
+
+void IncrementalMarking::DeactivateIncrementalWriteBarrierForSpace(
+ PagedSpace* space) {
+ PageIterator it(space);
+ while (it.has_next()) {
+ Page* p = it.next();
+ SetOldSpacePageFlags(p, false, false);
+ }
+}
+
+
+void IncrementalMarking::DeactivateIncrementalWriteBarrierForSpace(
+ NewSpace* space) {
+ NewSpacePageIterator it(space);
+ while (it.has_next()) {
+ NewSpacePage* p = it.next();
+ SetNewSpacePageFlags(p, false);
+ }
+}
+
+
+void IncrementalMarking::DeactivateIncrementalWriteBarrier() {
+ DeactivateIncrementalWriteBarrierForSpace(heap_->old_pointer_space());
+ DeactivateIncrementalWriteBarrierForSpace(heap_->old_data_space());
+ DeactivateIncrementalWriteBarrierForSpace(heap_->cell_space());
+ DeactivateIncrementalWriteBarrierForSpace(heap_->property_cell_space());
+ DeactivateIncrementalWriteBarrierForSpace(heap_->map_space());
+ DeactivateIncrementalWriteBarrierForSpace(heap_->code_space());
+ DeactivateIncrementalWriteBarrierForSpace(heap_->new_space());
+
+ LargePage* lop = heap_->lo_space()->first_page();
+ while (lop->is_valid()) {
+ SetOldSpacePageFlags(lop, false, false);
+ lop = lop->next_page();
+ }
+}
+
+
+void IncrementalMarking::ActivateIncrementalWriteBarrier(PagedSpace* space) {
+ PageIterator it(space);
+ while (it.has_next()) {
+ Page* p = it.next();
+ SetOldSpacePageFlags(p, true, is_compacting_);
+ }
+}
+
+
+void IncrementalMarking::ActivateIncrementalWriteBarrier(NewSpace* space) {
+ NewSpacePageIterator it(space->ToSpaceStart(), space->ToSpaceEnd());
+ while (it.has_next()) {
+ NewSpacePage* p = it.next();
+ SetNewSpacePageFlags(p, true);
+ }
+}
+
+
+void IncrementalMarking::ActivateIncrementalWriteBarrier() {
+ ActivateIncrementalWriteBarrier(heap_->old_pointer_space());
+ ActivateIncrementalWriteBarrier(heap_->old_data_space());
+ ActivateIncrementalWriteBarrier(heap_->cell_space());
+ ActivateIncrementalWriteBarrier(heap_->property_cell_space());
+ ActivateIncrementalWriteBarrier(heap_->map_space());
+ ActivateIncrementalWriteBarrier(heap_->code_space());
+ ActivateIncrementalWriteBarrier(heap_->new_space());
+
+ LargePage* lop = heap_->lo_space()->first_page();
+ while (lop->is_valid()) {
+ SetOldSpacePageFlags(lop, true, is_compacting_);
+ lop = lop->next_page();
+ }
+}
+
+
+bool IncrementalMarking::ShouldActivate() {
+ return WorthActivating() && heap_->NextGCIsLikelyToBeFull();
+}
+
+
+bool IncrementalMarking::WorthActivating() {
+#ifndef DEBUG
+ static const intptr_t kActivationThreshold = 8 * MB;
+#else
+ // TODO(gc) consider setting this to some low level so that some
+ // debug tests run with incremental marking and some without.
+ static const intptr_t kActivationThreshold = 0;
+#endif
+ // Only start incremental marking in a safe state: 1) when incremental
+ // marking is turned on, 2) when we are currently not in a GC, and
+ // 3) when we are currently not serializing or deserializing the heap.
+ return FLAG_incremental_marking && FLAG_incremental_marking_steps &&
+ heap_->gc_state() == Heap::NOT_IN_GC &&
+ !heap_->isolate()->serializer_enabled() &&
+ heap_->isolate()->IsInitialized() &&
+ heap_->PromotedSpaceSizeOfObjects() > kActivationThreshold;
+}
+
+
+void IncrementalMarking::ActivateGeneratedStub(Code* stub) {
+ DCHECK(RecordWriteStub::GetMode(stub) == RecordWriteStub::STORE_BUFFER_ONLY);
+
+ if (!IsMarking()) {
+ // Initially stub is generated in STORE_BUFFER_ONLY mode thus
+ // we don't need to do anything if incremental marking is
+ // not active.
+ } else if (IsCompacting()) {
+ RecordWriteStub::Patch(stub, RecordWriteStub::INCREMENTAL_COMPACTION);
+ } else {
+ RecordWriteStub::Patch(stub, RecordWriteStub::INCREMENTAL);
+ }
+}
+
+
+static void PatchIncrementalMarkingRecordWriteStubs(
+ Heap* heap, RecordWriteStub::Mode mode) {
+ UnseededNumberDictionary* stubs = heap->code_stubs();
+
+ int capacity = stubs->Capacity();
+ for (int i = 0; i < capacity; i++) {
+ Object* k = stubs->KeyAt(i);
+ if (stubs->IsKey(k)) {
+ uint32_t key = NumberToUint32(k);
+
+ if (CodeStub::MajorKeyFromKey(key) == CodeStub::RecordWrite) {
+ Object* e = stubs->ValueAt(i);
+ if (e->IsCode()) {
+ RecordWriteStub::Patch(Code::cast(e), mode);
+ }
+ }
+ }
+ }
+}
+
+
+void IncrementalMarking::EnsureMarkingDequeIsCommitted() {
+ if (marking_deque_memory_ == NULL) {
+ marking_deque_memory_ = new base::VirtualMemory(4 * MB);
+ }
+ if (!marking_deque_memory_committed_) {
+ bool success = marking_deque_memory_->Commit(
+ reinterpret_cast<Address>(marking_deque_memory_->address()),
+ marking_deque_memory_->size(),
+ false); // Not executable.
+ CHECK(success);
+ marking_deque_memory_committed_ = true;
+ }
+}
+
+
+void IncrementalMarking::UncommitMarkingDeque() {
+ if (state_ == STOPPED && marking_deque_memory_committed_) {
+ bool success = marking_deque_memory_->Uncommit(
+ reinterpret_cast<Address>(marking_deque_memory_->address()),
+ marking_deque_memory_->size());
+ CHECK(success);
+ marking_deque_memory_committed_ = false;
+ }
+}
+
+
+void IncrementalMarking::Start(CompactionFlag flag) {
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Start\n");
+ }
+ DCHECK(FLAG_incremental_marking);
+ DCHECK(FLAG_incremental_marking_steps);
+ DCHECK(state_ == STOPPED);
+ DCHECK(heap_->gc_state() == Heap::NOT_IN_GC);
+ DCHECK(!heap_->isolate()->serializer_enabled());
+ DCHECK(heap_->isolate()->IsInitialized());
+
+ ResetStepCounters();
+
+ if (!heap_->mark_compact_collector()->sweeping_in_progress()) {
+ StartMarking(flag);
+ } else {
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Start sweeping.\n");
+ }
+ state_ = SWEEPING;
+ }
+
+ heap_->new_space()->LowerInlineAllocationLimit(kAllocatedThreshold);
+}
+
+
+void IncrementalMarking::StartMarking(CompactionFlag flag) {
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Start marking\n");
+ }
+
+ is_compacting_ = !FLAG_never_compact && (flag == ALLOW_COMPACTION) &&
+ heap_->mark_compact_collector()->StartCompaction(
+ MarkCompactCollector::INCREMENTAL_COMPACTION);
+
+ state_ = MARKING;
+
+ RecordWriteStub::Mode mode = is_compacting_
+ ? RecordWriteStub::INCREMENTAL_COMPACTION
+ : RecordWriteStub::INCREMENTAL;
+
+ PatchIncrementalMarkingRecordWriteStubs(heap_, mode);
+
+ EnsureMarkingDequeIsCommitted();
+
+ // Initialize marking stack.
+ Address addr = static_cast<Address>(marking_deque_memory_->address());
+ size_t size = marking_deque_memory_->size();
+ if (FLAG_force_marking_deque_overflows) size = 64 * kPointerSize;
+ marking_deque_.Initialize(addr, addr + size);
+
+ ActivateIncrementalWriteBarrier();
+
+// Marking bits are cleared by the sweeper.
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ heap_->mark_compact_collector()->VerifyMarkbitsAreClean();
+ }
+#endif
+
+ heap_->CompletelyClearInstanceofCache();
+ heap_->isolate()->compilation_cache()->MarkCompactPrologue();
+
+ if (FLAG_cleanup_code_caches_at_gc) {
+ // We will mark cache black with a separate pass
+ // when we finish marking.
+ MarkObjectGreyDoNotEnqueue(heap_->polymorphic_code_cache());
+ }
+
+ // Mark strong roots grey.
+ IncrementalMarkingRootMarkingVisitor visitor(this);
+ heap_->IterateStrongRoots(&visitor, VISIT_ONLY_STRONG);
+
+ heap_->mark_compact_collector()->MarkWeakObjectToCodeTable();
+
+ // Ready to start incremental marking.
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Running\n");
+ }
+}
+
+
+void IncrementalMarking::PrepareForScavenge() {
+ if (!IsMarking()) return;
+ NewSpacePageIterator it(heap_->new_space()->FromSpaceStart(),
+ heap_->new_space()->FromSpaceEnd());
+ while (it.has_next()) {
+ Bitmap::Clear(it.next());
+ }
+}
+
+
+void IncrementalMarking::UpdateMarkingDequeAfterScavenge() {
+ if (!IsMarking()) return;
+
+ int current = marking_deque_.bottom();
+ int mask = marking_deque_.mask();
+ int limit = marking_deque_.top();
+ HeapObject** array = marking_deque_.array();
+ int new_top = current;
+
+ Map* filler_map = heap_->one_pointer_filler_map();
+
+ while (current != limit) {
+ HeapObject* obj = array[current];
+ DCHECK(obj->IsHeapObject());
+ current = ((current + 1) & mask);
+ if (heap_->InNewSpace(obj)) {
+ MapWord map_word = obj->map_word();
+ if (map_word.IsForwardingAddress()) {
+ HeapObject* dest = map_word.ToForwardingAddress();
+ array[new_top] = dest;
+ new_top = ((new_top + 1) & mask);
+ DCHECK(new_top != marking_deque_.bottom());
+#ifdef DEBUG
+ MarkBit mark_bit = Marking::MarkBitFrom(obj);
+ DCHECK(Marking::IsGrey(mark_bit) ||
+ (obj->IsFiller() && Marking::IsWhite(mark_bit)));
+#endif
+ }
+ } else if (obj->map() != filler_map) {
+ // Skip one word filler objects that appear on the
+ // stack when we perform in place array shift.
+ array[new_top] = obj;
+ new_top = ((new_top + 1) & mask);
+ DCHECK(new_top != marking_deque_.bottom());
+#ifdef DEBUG
+ MarkBit mark_bit = Marking::MarkBitFrom(obj);
+ MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
+ DCHECK(Marking::IsGrey(mark_bit) ||
+ (obj->IsFiller() && Marking::IsWhite(mark_bit)) ||
+ (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR) &&
+ Marking::IsBlack(mark_bit)));
+#endif
+ }
+ }
+ marking_deque_.set_top(new_top);
+}
+
+
+void IncrementalMarking::VisitObject(Map* map, HeapObject* obj, int size) {
+ MarkBit map_mark_bit = Marking::MarkBitFrom(map);
+ if (Marking::IsWhite(map_mark_bit)) {
+ WhiteToGreyAndPush(map, map_mark_bit);
+ }
+
+ IncrementalMarkingMarkingVisitor::IterateBody(map, obj);
+
+ MarkBit mark_bit = Marking::MarkBitFrom(obj);
+#if ENABLE_SLOW_DCHECKS
+ MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
+ SLOW_DCHECK(Marking::IsGrey(mark_bit) ||
+ (obj->IsFiller() && Marking::IsWhite(mark_bit)) ||
+ (chunk->IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR) &&
+ Marking::IsBlack(mark_bit)));
+#endif
+ MarkBlackOrKeepBlack(obj, mark_bit, size);
+}
+
+
+intptr_t IncrementalMarking::ProcessMarkingDeque(intptr_t bytes_to_process) {
+ intptr_t bytes_processed = 0;
+ Map* filler_map = heap_->one_pointer_filler_map();
+ while (!marking_deque_.IsEmpty() && bytes_processed < bytes_to_process) {
+ HeapObject* obj = marking_deque_.Pop();
+
+ // Explicitly skip one word fillers. Incremental markbit patterns are
+ // correct only for objects that occupy at least two words.
+ Map* map = obj->map();
+ if (map == filler_map) continue;
+
+ int size = obj->SizeFromMap(map);
+ unscanned_bytes_of_large_object_ = 0;
+ VisitObject(map, obj, size);
+ int delta = (size - unscanned_bytes_of_large_object_);
+ // TODO(jochen): remove after http://crbug.com/381820 is resolved.
+ CHECK_LT(0, delta);
+ bytes_processed += delta;
+ }
+ return bytes_processed;
+}
+
+
+void IncrementalMarking::ProcessMarkingDeque() {
+ Map* filler_map = heap_->one_pointer_filler_map();
+ while (!marking_deque_.IsEmpty()) {
+ HeapObject* obj = marking_deque_.Pop();
+
+ // Explicitly skip one word fillers. Incremental markbit patterns are
+ // correct only for objects that occupy at least two words.
+ Map* map = obj->map();
+ if (map == filler_map) continue;
+
+ VisitObject(map, obj, obj->SizeFromMap(map));
+ }
+}
+
+
+void IncrementalMarking::Hurry() {
+ if (state() == MARKING) {
+ double start = 0.0;
+ if (FLAG_trace_incremental_marking || FLAG_print_cumulative_gc_stat) {
+ start = base::OS::TimeCurrentMillis();
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Hurry\n");
+ }
+ }
+ // TODO(gc) hurry can mark objects it encounters black as mutator
+ // was stopped.
+ ProcessMarkingDeque();
+ state_ = COMPLETE;
+ if (FLAG_trace_incremental_marking || FLAG_print_cumulative_gc_stat) {
+ double end = base::OS::TimeCurrentMillis();
+ double delta = end - start;
+ heap_->tracer()->AddMarkingTime(delta);
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Complete (hurry), spent %d ms.\n",
+ static_cast<int>(delta));
+ }
+ }
+ }
+
+ if (FLAG_cleanup_code_caches_at_gc) {
+ PolymorphicCodeCache* poly_cache = heap_->polymorphic_code_cache();
+ Marking::GreyToBlack(Marking::MarkBitFrom(poly_cache));
+ MemoryChunk::IncrementLiveBytesFromGC(poly_cache->address(),
+ PolymorphicCodeCache::kSize);
+ }
+
+ Object* context = heap_->native_contexts_list();
+ while (!context->IsUndefined()) {
+ // GC can happen when the context is not fully initialized,
+ // so the cache can be undefined.
+ HeapObject* cache = HeapObject::cast(
+ Context::cast(context)->get(Context::NORMALIZED_MAP_CACHE_INDEX));
+ if (!cache->IsUndefined()) {
+ MarkBit mark_bit = Marking::MarkBitFrom(cache);
+ if (Marking::IsGrey(mark_bit)) {
+ Marking::GreyToBlack(mark_bit);
+ MemoryChunk::IncrementLiveBytesFromGC(cache->address(), cache->Size());
+ }
+ }
+ context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
+ }
+}
+
+
+void IncrementalMarking::Abort() {
+ if (IsStopped()) return;
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Aborting.\n");
+ }
+ heap_->new_space()->LowerInlineAllocationLimit(0);
+ IncrementalMarking::set_should_hurry(false);
+ ResetStepCounters();
+ if (IsMarking()) {
+ PatchIncrementalMarkingRecordWriteStubs(heap_,
+ RecordWriteStub::STORE_BUFFER_ONLY);
+ DeactivateIncrementalWriteBarrier();
+
+ if (is_compacting_) {
+ LargeObjectIterator it(heap_->lo_space());
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ Page* p = Page::FromAddress(obj->address());
+ if (p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) {
+ p->ClearFlag(Page::RESCAN_ON_EVACUATION);
+ }
+ }
+ }
+ }
+ heap_->isolate()->stack_guard()->ClearGC();
+ state_ = STOPPED;
+ is_compacting_ = false;
+}
+
+
+void IncrementalMarking::Finalize() {
+ Hurry();
+ state_ = STOPPED;
+ is_compacting_ = false;
+ heap_->new_space()->LowerInlineAllocationLimit(0);
+ IncrementalMarking::set_should_hurry(false);
+ ResetStepCounters();
+ PatchIncrementalMarkingRecordWriteStubs(heap_,
+ RecordWriteStub::STORE_BUFFER_ONLY);
+ DeactivateIncrementalWriteBarrier();
+ DCHECK(marking_deque_.IsEmpty());
+ heap_->isolate()->stack_guard()->ClearGC();
+}
+
+
+void IncrementalMarking::MarkingComplete(CompletionAction action) {
+ state_ = COMPLETE;
+ // We will set the stack guard to request a GC now. This will mean the rest
+ // of the GC gets performed as soon as possible (we can't do a GC here in a
+ // record-write context). If a few things get allocated between now and then
+ // that shouldn't make us do a scavenge and keep being incremental, so we set
+ // the should-hurry flag to indicate that there can't be much work left to do.
+ set_should_hurry(true);
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Complete (normal).\n");
+ }
+ if (action == GC_VIA_STACK_GUARD) {
+ heap_->isolate()->stack_guard()->RequestGC();
+ }
+}
+
+
+void IncrementalMarking::OldSpaceStep(intptr_t allocated) {
+ if (IsStopped() && ShouldActivate()) {
+ // TODO(hpayer): Let's play safe for now, but compaction should be
+ // in principle possible.
+ Start(PREVENT_COMPACTION);
+ } else {
+ Step(allocated * kFastMarking / kInitialMarkingSpeed, GC_VIA_STACK_GUARD);
+ }
+}
+
+
+void IncrementalMarking::SpeedUp() {
+ bool speed_up = false;
+
+ if ((steps_count_ % kMarkingSpeedAccellerationInterval) == 0) {
+ if (FLAG_trace_gc) {
+ PrintPID("Speed up marking after %d steps\n",
+ static_cast<int>(kMarkingSpeedAccellerationInterval));
+ }
+ speed_up = true;
+ }
+
+ bool space_left_is_very_small =
+ (old_generation_space_available_at_start_of_incremental_ < 10 * MB);
+
+ bool only_1_nth_of_space_that_was_available_still_left =
+ (SpaceLeftInOldSpace() * (marking_speed_ + 1) <
+ old_generation_space_available_at_start_of_incremental_);
+
+ if (space_left_is_very_small ||
+ only_1_nth_of_space_that_was_available_still_left) {
+ if (FLAG_trace_gc) PrintPID("Speed up marking because of low space left\n");
+ speed_up = true;
+ }
+
+ bool size_of_old_space_multiplied_by_n_during_marking =
+ (heap_->PromotedTotalSize() >
+ (marking_speed_ + 1) *
+ old_generation_space_used_at_start_of_incremental_);
+ if (size_of_old_space_multiplied_by_n_during_marking) {
+ speed_up = true;
+ if (FLAG_trace_gc) {
+ PrintPID("Speed up marking because of heap size increase\n");
+ }
+ }
+
+ int64_t promoted_during_marking =
+ heap_->PromotedTotalSize() -
+ old_generation_space_used_at_start_of_incremental_;
+ intptr_t delay = marking_speed_ * MB;
+ intptr_t scavenge_slack = heap_->MaxSemiSpaceSize();
+
+ // We try to scan at at least twice the speed that we are allocating.
+ if (promoted_during_marking > bytes_scanned_ / 2 + scavenge_slack + delay) {
+ if (FLAG_trace_gc) {
+ PrintPID("Speed up marking because marker was not keeping up\n");
+ }
+ speed_up = true;
+ }
+
+ if (speed_up) {
+ if (state_ != MARKING) {
+ if (FLAG_trace_gc) {
+ PrintPID("Postponing speeding up marking until marking starts\n");
+ }
+ } else {
+ marking_speed_ += kMarkingSpeedAccelleration;
+ marking_speed_ = static_cast<int>(
+ Min(kMaxMarkingSpeed, static_cast<intptr_t>(marking_speed_ * 1.3)));
+ if (FLAG_trace_gc) {
+ PrintPID("Marking speed increased to %d\n", marking_speed_);
+ }
+ }
+ }
+}
+
+
+void IncrementalMarking::Step(intptr_t allocated_bytes, CompletionAction action,
+ bool force_marking) {
+ if (heap_->gc_state() != Heap::NOT_IN_GC || !FLAG_incremental_marking ||
+ !FLAG_incremental_marking_steps ||
+ (state_ != SWEEPING && state_ != MARKING)) {
+ return;
+ }
+
+ allocated_ += allocated_bytes;
+
+ if (!force_marking && allocated_ < kAllocatedThreshold &&
+ write_barriers_invoked_since_last_step_ <
+ kWriteBarriersInvokedThreshold) {
+ return;
+ }
+
+ if (state_ == MARKING && no_marking_scope_depth_ > 0) return;
+
+ {
+ HistogramTimerScope incremental_marking_scope(
+ heap_->isolate()->counters()->gc_incremental_marking());
+ double start = base::OS::TimeCurrentMillis();
+
+ // The marking speed is driven either by the allocation rate or by the rate
+ // at which we are having to check the color of objects in the write
+ // barrier.
+ // It is possible for a tight non-allocating loop to run a lot of write
+ // barriers before we get here and check them (marking can only take place
+ // on
+ // allocation), so to reduce the lumpiness we don't use the write barriers
+ // invoked since last step directly to determine the amount of work to do.
+ intptr_t bytes_to_process =
+ marking_speed_ *
+ Max(allocated_, write_barriers_invoked_since_last_step_);
+ allocated_ = 0;
+ write_barriers_invoked_since_last_step_ = 0;
+
+ bytes_scanned_ += bytes_to_process;
+ intptr_t bytes_processed = 0;
+
+ if (state_ == SWEEPING) {
+ if (heap_->mark_compact_collector()->sweeping_in_progress() &&
+ heap_->mark_compact_collector()->IsSweepingCompleted()) {
+ heap_->mark_compact_collector()->EnsureSweepingCompleted();
+ }
+ if (!heap_->mark_compact_collector()->sweeping_in_progress()) {
+ bytes_scanned_ = 0;
+ StartMarking(PREVENT_COMPACTION);
+ }
+ } else if (state_ == MARKING) {
+ bytes_processed = ProcessMarkingDeque(bytes_to_process);
+ if (marking_deque_.IsEmpty()) MarkingComplete(action);
+ }
+
+ steps_count_++;
+
+ // Speed up marking if we are marking too slow or if we are almost done
+ // with marking.
+ SpeedUp();
+
+ double end = base::OS::TimeCurrentMillis();
+ double duration = (end - start);
+ // Note that we report zero bytes here when sweeping was in progress or
+ // when we just started incremental marking. In these cases we did not
+ // process the marking deque.
+ heap_->tracer()->AddIncrementalMarkingStep(duration, bytes_processed);
+ }
+}
+
+
+void IncrementalMarking::ResetStepCounters() {
+ steps_count_ = 0;
+ old_generation_space_available_at_start_of_incremental_ =
+ SpaceLeftInOldSpace();
+ old_generation_space_used_at_start_of_incremental_ =
+ heap_->PromotedTotalSize();
+ bytes_rescanned_ = 0;
+ marking_speed_ = kInitialMarkingSpeed;
+ bytes_scanned_ = 0;
+ write_barriers_invoked_since_last_step_ = 0;
+}
+
+
+int64_t IncrementalMarking::SpaceLeftInOldSpace() {
+ return heap_->MaxOldGenerationSize() - heap_->PromotedSpaceSizeOfObjects();
+}
+}
+} // namespace v8::internal
diff --git a/src/heap/incremental-marking.h b/src/heap/incremental-marking.h
new file mode 100644
index 0000000..e4a8e97
--- /dev/null
+++ b/src/heap/incremental-marking.h
@@ -0,0 +1,226 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_INCREMENTAL_MARKING_H_
+#define V8_HEAP_INCREMENTAL_MARKING_H_
+
+
+#include "src/execution.h"
+#include "src/heap/mark-compact.h"
+#include "src/objects.h"
+
+namespace v8 {
+namespace internal {
+
+
+class IncrementalMarking {
+ public:
+ enum State { STOPPED, SWEEPING, MARKING, COMPLETE };
+
+ enum CompletionAction { GC_VIA_STACK_GUARD, NO_GC_VIA_STACK_GUARD };
+
+ explicit IncrementalMarking(Heap* heap);
+
+ static void Initialize();
+
+ void TearDown();
+
+ State state() {
+ DCHECK(state_ == STOPPED || FLAG_incremental_marking);
+ return state_;
+ }
+
+ bool should_hurry() { return should_hurry_; }
+ void set_should_hurry(bool val) { should_hurry_ = val; }
+
+ inline bool IsStopped() { return state() == STOPPED; }
+
+ INLINE(bool IsMarking()) { return state() >= MARKING; }
+
+ inline bool IsMarkingIncomplete() { return state() == MARKING; }
+
+ inline bool IsComplete() { return state() == COMPLETE; }
+
+ bool WorthActivating();
+
+ bool ShouldActivate();
+
+ enum CompactionFlag { ALLOW_COMPACTION, PREVENT_COMPACTION };
+
+ void Start(CompactionFlag flag = ALLOW_COMPACTION);
+
+ void Stop();
+
+ void PrepareForScavenge();
+
+ void UpdateMarkingDequeAfterScavenge();
+
+ void Hurry();
+
+ void Finalize();
+
+ void Abort();
+
+ void MarkingComplete(CompletionAction action);
+
+ // It's hard to know how much work the incremental marker should do to make
+ // progress in the face of the mutator creating new work for it. We start
+ // of at a moderate rate of work and gradually increase the speed of the
+ // incremental marker until it completes.
+ // Do some marking every time this much memory has been allocated or that many
+ // heavy (color-checking) write barriers have been invoked.
+ static const intptr_t kAllocatedThreshold = 65536;
+ static const intptr_t kWriteBarriersInvokedThreshold = 32768;
+ // Start off by marking this many times more memory than has been allocated.
+ static const intptr_t kInitialMarkingSpeed = 1;
+ // But if we are promoting a lot of data we need to mark faster to keep up
+ // with the data that is entering the old space through promotion.
+ static const intptr_t kFastMarking = 3;
+ // After this many steps we increase the marking/allocating factor.
+ static const intptr_t kMarkingSpeedAccellerationInterval = 1024;
+ // This is how much we increase the marking/allocating factor by.
+ static const intptr_t kMarkingSpeedAccelleration = 2;
+ static const intptr_t kMaxMarkingSpeed = 1000;
+
+ void OldSpaceStep(intptr_t allocated);
+
+ void Step(intptr_t allocated, CompletionAction action,
+ bool force_marking = false);
+
+ inline void RestartIfNotMarking() {
+ if (state_ == COMPLETE) {
+ state_ = MARKING;
+ if (FLAG_trace_incremental_marking) {
+ PrintF("[IncrementalMarking] Restarting (new grey objects)\n");
+ }
+ }
+ }
+
+ static void RecordWriteFromCode(HeapObject* obj, Object** slot,
+ Isolate* isolate);
+
+ // Record a slot for compaction. Returns false for objects that are
+ // guaranteed to be rescanned or not guaranteed to survive.
+ //
+ // No slots in white objects should be recorded, as some slots are typed and
+ // cannot be interpreted correctly if the underlying object does not survive
+ // the incremental cycle (stays white).
+ INLINE(bool BaseRecordWrite(HeapObject* obj, Object** slot, Object* value));
+ INLINE(void RecordWrite(HeapObject* obj, Object** slot, Object* value));
+ INLINE(void RecordWriteIntoCode(HeapObject* obj, RelocInfo* rinfo,
+ Object* value));
+ INLINE(void RecordWriteOfCodeEntry(JSFunction* host, Object** slot,
+ Code* value));
+
+
+ void RecordWriteSlow(HeapObject* obj, Object** slot, Object* value);
+ void RecordWriteIntoCodeSlow(HeapObject* obj, RelocInfo* rinfo,
+ Object* value);
+ void RecordWriteOfCodeEntrySlow(JSFunction* host, Object** slot, Code* value);
+ void RecordCodeTargetPatch(Code* host, Address pc, HeapObject* value);
+ void RecordCodeTargetPatch(Address pc, HeapObject* value);
+
+ inline void RecordWrites(HeapObject* obj);
+
+ inline void BlackToGreyAndUnshift(HeapObject* obj, MarkBit mark_bit);
+
+ inline void WhiteToGreyAndPush(HeapObject* obj, MarkBit mark_bit);
+
+ inline void SetOldSpacePageFlags(MemoryChunk* chunk) {
+ SetOldSpacePageFlags(chunk, IsMarking(), IsCompacting());
+ }
+
+ inline void SetNewSpacePageFlags(NewSpacePage* chunk) {
+ SetNewSpacePageFlags(chunk, IsMarking());
+ }
+
+ MarkingDeque* marking_deque() { return &marking_deque_; }
+
+ bool IsCompacting() { return IsMarking() && is_compacting_; }
+
+ void ActivateGeneratedStub(Code* stub);
+
+ void NotifyOfHighPromotionRate() {
+ if (IsMarking()) {
+ if (marking_speed_ < kFastMarking) {
+ if (FLAG_trace_gc) {
+ PrintPID(
+ "Increasing marking speed to %d "
+ "due to high promotion rate\n",
+ static_cast<int>(kFastMarking));
+ }
+ marking_speed_ = kFastMarking;
+ }
+ }
+ }
+
+ void EnterNoMarkingScope() { no_marking_scope_depth_++; }
+
+ void LeaveNoMarkingScope() { no_marking_scope_depth_--; }
+
+ void UncommitMarkingDeque();
+
+ void NotifyIncompleteScanOfObject(int unscanned_bytes) {
+ unscanned_bytes_of_large_object_ = unscanned_bytes;
+ }
+
+ private:
+ int64_t SpaceLeftInOldSpace();
+
+ void SpeedUp();
+
+ void ResetStepCounters();
+
+ void StartMarking(CompactionFlag flag);
+
+ void ActivateIncrementalWriteBarrier(PagedSpace* space);
+ static void ActivateIncrementalWriteBarrier(NewSpace* space);
+ void ActivateIncrementalWriteBarrier();
+
+ static void DeactivateIncrementalWriteBarrierForSpace(PagedSpace* space);
+ static void DeactivateIncrementalWriteBarrierForSpace(NewSpace* space);
+ void DeactivateIncrementalWriteBarrier();
+
+ static void SetOldSpacePageFlags(MemoryChunk* chunk, bool is_marking,
+ bool is_compacting);
+
+ static void SetNewSpacePageFlags(NewSpacePage* chunk, bool is_marking);
+
+ void EnsureMarkingDequeIsCommitted();
+
+ INLINE(void ProcessMarkingDeque());
+
+ INLINE(intptr_t ProcessMarkingDeque(intptr_t bytes_to_process));
+
+ INLINE(void VisitObject(Map* map, HeapObject* obj, int size));
+
+ Heap* heap_;
+
+ State state_;
+ bool is_compacting_;
+
+ base::VirtualMemory* marking_deque_memory_;
+ bool marking_deque_memory_committed_;
+ MarkingDeque marking_deque_;
+
+ int steps_count_;
+ int64_t old_generation_space_available_at_start_of_incremental_;
+ int64_t old_generation_space_used_at_start_of_incremental_;
+ int64_t bytes_rescanned_;
+ bool should_hurry_;
+ int marking_speed_;
+ intptr_t bytes_scanned_;
+ intptr_t allocated_;
+ intptr_t write_barriers_invoked_since_last_step_;
+
+ int no_marking_scope_depth_;
+
+ int unscanned_bytes_of_large_object_;
+
+ DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
+};
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_INCREMENTAL_MARKING_H_
diff --git a/src/heap/mark-compact-inl.h b/src/heap/mark-compact-inl.h
new file mode 100644
index 0000000..66b0a59
--- /dev/null
+++ b/src/heap/mark-compact-inl.h
@@ -0,0 +1,72 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_MARK_COMPACT_INL_H_
+#define V8_HEAP_MARK_COMPACT_INL_H_
+
+#include "src/heap/mark-compact.h"
+#include "src/isolate.h"
+
+
+namespace v8 {
+namespace internal {
+
+
+MarkBit Marking::MarkBitFrom(Address addr) {
+ MemoryChunk* p = MemoryChunk::FromAddress(addr);
+ return p->markbits()->MarkBitFromIndex(p->AddressToMarkbitIndex(addr),
+ p->ContainsOnlyData());
+}
+
+
+void MarkCompactCollector::SetFlags(int flags) {
+ reduce_memory_footprint_ = ((flags & Heap::kReduceMemoryFootprintMask) != 0);
+ abort_incremental_marking_ =
+ ((flags & Heap::kAbortIncrementalMarkingMask) != 0);
+}
+
+
+void MarkCompactCollector::MarkObject(HeapObject* obj, MarkBit mark_bit) {
+ DCHECK(Marking::MarkBitFrom(obj) == mark_bit);
+ if (!mark_bit.Get()) {
+ mark_bit.Set();
+ MemoryChunk::IncrementLiveBytesFromGC(obj->address(), obj->Size());
+ DCHECK(IsMarked(obj));
+ DCHECK(obj->GetIsolate()->heap()->Contains(obj));
+ marking_deque_.PushBlack(obj);
+ }
+}
+
+
+void MarkCompactCollector::SetMark(HeapObject* obj, MarkBit mark_bit) {
+ DCHECK(!mark_bit.Get());
+ DCHECK(Marking::MarkBitFrom(obj) == mark_bit);
+ mark_bit.Set();
+ MemoryChunk::IncrementLiveBytesFromGC(obj->address(), obj->Size());
+}
+
+
+bool MarkCompactCollector::IsMarked(Object* obj) {
+ DCHECK(obj->IsHeapObject());
+ HeapObject* heap_object = HeapObject::cast(obj);
+ return Marking::MarkBitFrom(heap_object).Get();
+}
+
+
+void MarkCompactCollector::RecordSlot(Object** anchor_slot, Object** slot,
+ Object* object,
+ SlotsBuffer::AdditionMode mode) {
+ Page* object_page = Page::FromAddress(reinterpret_cast<Address>(object));
+ if (object_page->IsEvacuationCandidate() &&
+ !ShouldSkipEvacuationSlotRecording(anchor_slot)) {
+ if (!SlotsBuffer::AddTo(&slots_buffer_allocator_,
+ object_page->slots_buffer_address(), slot, mode)) {
+ EvictEvacuationCandidate(object_page);
+ }
+ }
+}
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_MARK_COMPACT_INL_H_
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
new file mode 100644
index 0000000..9f9a658
--- /dev/null
+++ b/src/heap/mark-compact.cc
@@ -0,0 +1,4562 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#include "src/base/atomicops.h"
+#include "src/base/bits.h"
+#include "src/code-stubs.h"
+#include "src/compilation-cache.h"
+#include "src/cpu-profiler.h"
+#include "src/deoptimizer.h"
+#include "src/execution.h"
+#include "src/gdb-jit.h"
+#include "src/global-handles.h"
+#include "src/heap/incremental-marking.h"
+#include "src/heap/mark-compact.h"
+#include "src/heap/objects-visiting.h"
+#include "src/heap/objects-visiting-inl.h"
+#include "src/heap/spaces-inl.h"
+#include "src/heap/sweeper-thread.h"
+#include "src/heap-profiler.h"
+#include "src/ic/ic.h"
+#include "src/ic/stub-cache.h"
+
+namespace v8 {
+namespace internal {
+
+
+const char* Marking::kWhiteBitPattern = "00";
+const char* Marking::kBlackBitPattern = "10";
+const char* Marking::kGreyBitPattern = "11";
+const char* Marking::kImpossibleBitPattern = "01";
+
+
+// -------------------------------------------------------------------------
+// MarkCompactCollector
+
+MarkCompactCollector::MarkCompactCollector(Heap* heap)
+ : // NOLINT
+#ifdef DEBUG
+ state_(IDLE),
+#endif
+ reduce_memory_footprint_(false),
+ abort_incremental_marking_(false),
+ marking_parity_(ODD_MARKING_PARITY),
+ compacting_(false),
+ was_marked_incrementally_(false),
+ sweeping_in_progress_(false),
+ pending_sweeper_jobs_semaphore_(0),
+ sequential_sweeping_(false),
+ migration_slots_buffer_(NULL),
+ heap_(heap),
+ code_flusher_(NULL),
+ have_code_to_deoptimize_(false) {
+}
+
+#ifdef VERIFY_HEAP
+class VerifyMarkingVisitor : public ObjectVisitor {
+ public:
+ explicit VerifyMarkingVisitor(Heap* heap) : heap_(heap) {}
+
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** current = start; current < end; current++) {
+ if ((*current)->IsHeapObject()) {
+ HeapObject* object = HeapObject::cast(*current);
+ CHECK(heap_->mark_compact_collector()->IsMarked(object));
+ }
+ }
+ }
+
+ void VisitEmbeddedPointer(RelocInfo* rinfo) {
+ DCHECK(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT);
+ if (!rinfo->host()->IsWeakObject(rinfo->target_object())) {
+ Object* p = rinfo->target_object();
+ VisitPointer(&p);
+ }
+ }
+
+ void VisitCell(RelocInfo* rinfo) {
+ Code* code = rinfo->host();
+ DCHECK(rinfo->rmode() == RelocInfo::CELL);
+ if (!code->IsWeakObject(rinfo->target_cell())) {
+ ObjectVisitor::VisitCell(rinfo);
+ }
+ }
+
+ private:
+ Heap* heap_;
+};
+
+
+static void VerifyMarking(Heap* heap, Address bottom, Address top) {
+ VerifyMarkingVisitor visitor(heap);
+ HeapObject* object;
+ Address next_object_must_be_here_or_later = bottom;
+
+ for (Address current = bottom; current < top; current += kPointerSize) {
+ object = HeapObject::FromAddress(current);
+ if (MarkCompactCollector::IsMarked(object)) {
+ CHECK(current >= next_object_must_be_here_or_later);
+ object->Iterate(&visitor);
+ next_object_must_be_here_or_later = current + object->Size();
+ }
+ }
+}
+
+
+static void VerifyMarking(NewSpace* space) {
+ Address end = space->top();
+ NewSpacePageIterator it(space->bottom(), end);
+ // The bottom position is at the start of its page. Allows us to use
+ // page->area_start() as start of range on all pages.
+ CHECK_EQ(space->bottom(),
+ NewSpacePage::FromAddress(space->bottom())->area_start());
+ while (it.has_next()) {
+ NewSpacePage* page = it.next();
+ Address limit = it.has_next() ? page->area_end() : end;
+ CHECK(limit == end || !page->Contains(end));
+ VerifyMarking(space->heap(), page->area_start(), limit);
+ }
+}
+
+
+static void VerifyMarking(PagedSpace* space) {
+ PageIterator it(space);
+
+ while (it.has_next()) {
+ Page* p = it.next();
+ VerifyMarking(space->heap(), p->area_start(), p->area_end());
+ }
+}
+
+
+static void VerifyMarking(Heap* heap) {
+ VerifyMarking(heap->old_pointer_space());
+ VerifyMarking(heap->old_data_space());
+ VerifyMarking(heap->code_space());
+ VerifyMarking(heap->cell_space());
+ VerifyMarking(heap->property_cell_space());
+ VerifyMarking(heap->map_space());
+ VerifyMarking(heap->new_space());
+
+ VerifyMarkingVisitor visitor(heap);
+
+ LargeObjectIterator it(heap->lo_space());
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ if (MarkCompactCollector::IsMarked(obj)) {
+ obj->Iterate(&visitor);
+ }
+ }
+
+ heap->IterateStrongRoots(&visitor, VISIT_ONLY_STRONG);
+}
+
+
+class VerifyEvacuationVisitor : public ObjectVisitor {
+ public:
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** current = start; current < end; current++) {
+ if ((*current)->IsHeapObject()) {
+ HeapObject* object = HeapObject::cast(*current);
+ CHECK(!MarkCompactCollector::IsOnEvacuationCandidate(object));
+ }
+ }
+ }
+};
+
+
+static void VerifyEvacuation(Page* page) {
+ VerifyEvacuationVisitor visitor;
+ HeapObjectIterator iterator(page, NULL);
+ for (HeapObject* heap_object = iterator.Next(); heap_object != NULL;
+ heap_object = iterator.Next()) {
+ // We skip free space objects.
+ if (!heap_object->IsFiller()) {
+ heap_object->Iterate(&visitor);
+ }
+ }
+}
+
+
+static void VerifyEvacuation(NewSpace* space) {
+ NewSpacePageIterator it(space->bottom(), space->top());
+ VerifyEvacuationVisitor visitor;
+
+ while (it.has_next()) {
+ NewSpacePage* page = it.next();
+ Address current = page->area_start();
+ Address limit = it.has_next() ? page->area_end() : space->top();
+ CHECK(limit == space->top() || !page->Contains(space->top()));
+ while (current < limit) {
+ HeapObject* object = HeapObject::FromAddress(current);
+ object->Iterate(&visitor);
+ current += object->Size();
+ }
+ }
+}
+
+
+static void VerifyEvacuation(Heap* heap, PagedSpace* space) {
+ if (FLAG_use_allocation_folding &&
+ (space == heap->old_pointer_space() || space == heap->old_data_space())) {
+ return;
+ }
+ PageIterator it(space);
+
+ while (it.has_next()) {
+ Page* p = it.next();
+ if (p->IsEvacuationCandidate()) continue;
+ VerifyEvacuation(p);
+ }
+}
+
+
+static void VerifyEvacuation(Heap* heap) {
+ VerifyEvacuation(heap, heap->old_pointer_space());
+ VerifyEvacuation(heap, heap->old_data_space());
+ VerifyEvacuation(heap, heap->code_space());
+ VerifyEvacuation(heap, heap->cell_space());
+ VerifyEvacuation(heap, heap->property_cell_space());
+ VerifyEvacuation(heap, heap->map_space());
+ VerifyEvacuation(heap->new_space());
+
+ VerifyEvacuationVisitor visitor;
+ heap->IterateStrongRoots(&visitor, VISIT_ALL);
+}
+#endif // VERIFY_HEAP
+
+
+#ifdef DEBUG
+class VerifyNativeContextSeparationVisitor : public ObjectVisitor {
+ public:
+ VerifyNativeContextSeparationVisitor() : current_native_context_(NULL) {}
+
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** current = start; current < end; current++) {
+ if ((*current)->IsHeapObject()) {
+ HeapObject* object = HeapObject::cast(*current);
+ if (object->IsString()) continue;
+ switch (object->map()->instance_type()) {
+ case JS_FUNCTION_TYPE:
+ CheckContext(JSFunction::cast(object)->context());
+ break;
+ case JS_GLOBAL_PROXY_TYPE:
+ CheckContext(JSGlobalProxy::cast(object)->native_context());
+ break;
+ case JS_GLOBAL_OBJECT_TYPE:
+ case JS_BUILTINS_OBJECT_TYPE:
+ CheckContext(GlobalObject::cast(object)->native_context());
+ break;
+ case JS_ARRAY_TYPE:
+ case JS_DATE_TYPE:
+ case JS_OBJECT_TYPE:
+ case JS_REGEXP_TYPE:
+ VisitPointer(HeapObject::RawField(object, JSObject::kMapOffset));
+ break;
+ case MAP_TYPE:
+ VisitPointer(HeapObject::RawField(object, Map::kPrototypeOffset));
+ VisitPointer(HeapObject::RawField(object, Map::kConstructorOffset));
+ break;
+ case FIXED_ARRAY_TYPE:
+ if (object->IsContext()) {
+ CheckContext(object);
+ } else {
+ FixedArray* array = FixedArray::cast(object);
+ int length = array->length();
+ // Set array length to zero to prevent cycles while iterating
+ // over array bodies, this is easier than intrusive marking.
+ array->set_length(0);
+ array->IterateBody(FIXED_ARRAY_TYPE, FixedArray::SizeFor(length),
+ this);
+ array->set_length(length);
+ }
+ break;
+ case CELL_TYPE:
+ case JS_PROXY_TYPE:
+ case JS_VALUE_TYPE:
+ case TYPE_FEEDBACK_INFO_TYPE:
+ object->Iterate(this);
+ break;
+ case DECLARED_ACCESSOR_INFO_TYPE:
+ case EXECUTABLE_ACCESSOR_INFO_TYPE:
+ case BYTE_ARRAY_TYPE:
+ case CALL_HANDLER_INFO_TYPE:
+ case CODE_TYPE:
+ case FIXED_DOUBLE_ARRAY_TYPE:
+ case HEAP_NUMBER_TYPE:
+ case MUTABLE_HEAP_NUMBER_TYPE:
+ case INTERCEPTOR_INFO_TYPE:
+ case ODDBALL_TYPE:
+ case SCRIPT_TYPE:
+ case SHARED_FUNCTION_INFO_TYPE:
+ break;
+ default:
+ UNREACHABLE();
+ }
+ }
+ }
+ }
+
+ private:
+ void CheckContext(Object* context) {
+ if (!context->IsContext()) return;
+ Context* native_context = Context::cast(context)->native_context();
+ if (current_native_context_ == NULL) {
+ current_native_context_ = native_context;
+ } else {
+ CHECK_EQ(current_native_context_, native_context);
+ }
+ }
+
+ Context* current_native_context_;
+};
+
+
+static void VerifyNativeContextSeparation(Heap* heap) {
+ HeapObjectIterator it(heap->code_space());
+
+ for (Object* object = it.Next(); object != NULL; object = it.Next()) {
+ VerifyNativeContextSeparationVisitor visitor;
+ Code::cast(object)->CodeIterateBody(&visitor);
+ }
+}
+#endif
+
+
+void MarkCompactCollector::SetUp() {
+ free_list_old_data_space_.Reset(new FreeList(heap_->old_data_space()));
+ free_list_old_pointer_space_.Reset(new FreeList(heap_->old_pointer_space()));
+}
+
+
+void MarkCompactCollector::TearDown() { AbortCompaction(); }
+
+
+void MarkCompactCollector::AddEvacuationCandidate(Page* p) {
+ p->MarkEvacuationCandidate();
+ evacuation_candidates_.Add(p);
+}
+
+
+static void TraceFragmentation(PagedSpace* space) {
+ int number_of_pages = space->CountTotalPages();
+ intptr_t reserved = (number_of_pages * space->AreaSize());
+ intptr_t free = reserved - space->SizeOfObjects();
+ PrintF("[%s]: %d pages, %d (%.1f%%) free\n",
+ AllocationSpaceName(space->identity()), number_of_pages,
+ static_cast<int>(free), static_cast<double>(free) * 100 / reserved);
+}
+
+
+bool MarkCompactCollector::StartCompaction(CompactionMode mode) {
+ if (!compacting_) {
+ DCHECK(evacuation_candidates_.length() == 0);
+
+#ifdef ENABLE_GDB_JIT_INTERFACE
+ // If GDBJIT interface is active disable compaction.
+ if (FLAG_gdbjit) return false;
+#endif
+
+ CollectEvacuationCandidates(heap()->old_pointer_space());
+ CollectEvacuationCandidates(heap()->old_data_space());
+
+ if (FLAG_compact_code_space && (mode == NON_INCREMENTAL_COMPACTION ||
+ FLAG_incremental_code_compaction)) {
+ CollectEvacuationCandidates(heap()->code_space());
+ } else if (FLAG_trace_fragmentation) {
+ TraceFragmentation(heap()->code_space());
+ }
+
+ if (FLAG_trace_fragmentation) {
+ TraceFragmentation(heap()->map_space());
+ TraceFragmentation(heap()->cell_space());
+ TraceFragmentation(heap()->property_cell_space());
+ }
+
+ heap()->old_pointer_space()->EvictEvacuationCandidatesFromFreeLists();
+ heap()->old_data_space()->EvictEvacuationCandidatesFromFreeLists();
+ heap()->code_space()->EvictEvacuationCandidatesFromFreeLists();
+
+ compacting_ = evacuation_candidates_.length() > 0;
+ }
+
+ return compacting_;
+}
+
+
+void MarkCompactCollector::CollectGarbage() {
+ // Make sure that Prepare() has been called. The individual steps below will
+ // update the state as they proceed.
+ DCHECK(state_ == PREPARE_GC);
+
+ MarkLiveObjects();
+ DCHECK(heap_->incremental_marking()->IsStopped());
+
+ if (FLAG_collect_maps) ClearNonLiveReferences();
+
+ ClearWeakCollections();
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ VerifyMarking(heap_);
+ }
+#endif
+
+ SweepSpaces();
+
+#ifdef DEBUG
+ if (FLAG_verify_native_context_separation) {
+ VerifyNativeContextSeparation(heap_);
+ }
+#endif
+
+#ifdef VERIFY_HEAP
+ if (heap()->weak_embedded_objects_verification_enabled()) {
+ VerifyWeakEmbeddedObjectsInCode();
+ }
+ if (FLAG_collect_maps && FLAG_omit_map_checks_for_leaf_maps) {
+ VerifyOmittedMapChecks();
+ }
+#endif
+
+ Finish();
+
+ if (marking_parity_ == EVEN_MARKING_PARITY) {
+ marking_parity_ = ODD_MARKING_PARITY;
+ } else {
+ DCHECK(marking_parity_ == ODD_MARKING_PARITY);
+ marking_parity_ = EVEN_MARKING_PARITY;
+ }
+}
+
+
+#ifdef VERIFY_HEAP
+void MarkCompactCollector::VerifyMarkbitsAreClean(PagedSpace* space) {
+ PageIterator it(space);
+
+ while (it.has_next()) {
+ Page* p = it.next();
+ CHECK(p->markbits()->IsClean());
+ CHECK_EQ(0, p->LiveBytes());
+ }
+}
+
+
+void MarkCompactCollector::VerifyMarkbitsAreClean(NewSpace* space) {
+ NewSpacePageIterator it(space->bottom(), space->top());
+
+ while (it.has_next()) {
+ NewSpacePage* p = it.next();
+ CHECK(p->markbits()->IsClean());
+ CHECK_EQ(0, p->LiveBytes());
+ }
+}
+
+
+void MarkCompactCollector::VerifyMarkbitsAreClean() {
+ VerifyMarkbitsAreClean(heap_->old_pointer_space());
+ VerifyMarkbitsAreClean(heap_->old_data_space());
+ VerifyMarkbitsAreClean(heap_->code_space());
+ VerifyMarkbitsAreClean(heap_->cell_space());
+ VerifyMarkbitsAreClean(heap_->property_cell_space());
+ VerifyMarkbitsAreClean(heap_->map_space());
+ VerifyMarkbitsAreClean(heap_->new_space());
+
+ LargeObjectIterator it(heap_->lo_space());
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ MarkBit mark_bit = Marking::MarkBitFrom(obj);
+ CHECK(Marking::IsWhite(mark_bit));
+ CHECK_EQ(0, Page::FromAddress(obj->address())->LiveBytes());
+ }
+}
+
+
+void MarkCompactCollector::VerifyWeakEmbeddedObjectsInCode() {
+ HeapObjectIterator code_iterator(heap()->code_space());
+ for (HeapObject* obj = code_iterator.Next(); obj != NULL;
+ obj = code_iterator.Next()) {
+ Code* code = Code::cast(obj);
+ if (!code->is_optimized_code() && !code->is_weak_stub()) continue;
+ if (WillBeDeoptimized(code)) continue;
+ code->VerifyEmbeddedObjectsDependency();
+ }
+}
+
+
+void MarkCompactCollector::VerifyOmittedMapChecks() {
+ HeapObjectIterator iterator(heap()->map_space());
+ for (HeapObject* obj = iterator.Next(); obj != NULL; obj = iterator.Next()) {
+ Map* map = Map::cast(obj);
+ map->VerifyOmittedMapChecks();
+ }
+}
+#endif // VERIFY_HEAP
+
+
+static void ClearMarkbitsInPagedSpace(PagedSpace* space) {
+ PageIterator it(space);
+
+ while (it.has_next()) {
+ Bitmap::Clear(it.next());
+ }
+}
+
+
+static void ClearMarkbitsInNewSpace(NewSpace* space) {
+ NewSpacePageIterator it(space->ToSpaceStart(), space->ToSpaceEnd());
+
+ while (it.has_next()) {
+ Bitmap::Clear(it.next());
+ }
+}
+
+
+void MarkCompactCollector::ClearMarkbits() {
+ ClearMarkbitsInPagedSpace(heap_->code_space());
+ ClearMarkbitsInPagedSpace(heap_->map_space());
+ ClearMarkbitsInPagedSpace(heap_->old_pointer_space());
+ ClearMarkbitsInPagedSpace(heap_->old_data_space());
+ ClearMarkbitsInPagedSpace(heap_->cell_space());
+ ClearMarkbitsInPagedSpace(heap_->property_cell_space());
+ ClearMarkbitsInNewSpace(heap_->new_space());
+
+ LargeObjectIterator it(heap_->lo_space());
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ MarkBit mark_bit = Marking::MarkBitFrom(obj);
+ mark_bit.Clear();
+ mark_bit.Next().Clear();
+ Page::FromAddress(obj->address())->ResetProgressBar();
+ Page::FromAddress(obj->address())->ResetLiveBytes();
+ }
+}
+
+
+class MarkCompactCollector::SweeperTask : public v8::Task {
+ public:
+ SweeperTask(Heap* heap, PagedSpace* space) : heap_(heap), space_(space) {}
+
+ virtual ~SweeperTask() {}
+
+ private:
+ // v8::Task overrides.
+ virtual void Run() OVERRIDE {
+ heap_->mark_compact_collector()->SweepInParallel(space_, 0);
+ heap_->mark_compact_collector()->pending_sweeper_jobs_semaphore_.Signal();
+ }
+
+ Heap* heap_;
+ PagedSpace* space_;
+
+ DISALLOW_COPY_AND_ASSIGN(SweeperTask);
+};
+
+
+void MarkCompactCollector::StartSweeperThreads() {
+ DCHECK(free_list_old_pointer_space_.get()->IsEmpty());
+ DCHECK(free_list_old_data_space_.get()->IsEmpty());
+ sweeping_in_progress_ = true;
+ for (int i = 0; i < isolate()->num_sweeper_threads(); i++) {
+ isolate()->sweeper_threads()[i]->StartSweeping();
+ }
+ if (FLAG_job_based_sweeping) {
+ V8::GetCurrentPlatform()->CallOnBackgroundThread(
+ new SweeperTask(heap(), heap()->old_data_space()),
+ v8::Platform::kShortRunningTask);
+ V8::GetCurrentPlatform()->CallOnBackgroundThread(
+ new SweeperTask(heap(), heap()->old_pointer_space()),
+ v8::Platform::kShortRunningTask);
+ }
+}
+
+
+void MarkCompactCollector::EnsureSweepingCompleted() {
+ DCHECK(sweeping_in_progress_ == true);
+
+ // If sweeping is not completed, we try to complete it here. If we do not
+ // have sweeper threads we have to complete since we do not have a good
+ // indicator for a swept space in that case.
+ if (!AreSweeperThreadsActivated() || !IsSweepingCompleted()) {
+ SweepInParallel(heap()->paged_space(OLD_DATA_SPACE), 0);
+ SweepInParallel(heap()->paged_space(OLD_POINTER_SPACE), 0);
+ }
+
+ for (int i = 0; i < isolate()->num_sweeper_threads(); i++) {
+ isolate()->sweeper_threads()[i]->WaitForSweeperThread();
+ }
+ if (FLAG_job_based_sweeping) {
+ // Wait twice for both jobs.
+ pending_sweeper_jobs_semaphore_.Wait();
+ pending_sweeper_jobs_semaphore_.Wait();
+ }
+ ParallelSweepSpacesComplete();
+ sweeping_in_progress_ = false;
+ RefillFreeList(heap()->paged_space(OLD_DATA_SPACE));
+ RefillFreeList(heap()->paged_space(OLD_POINTER_SPACE));
+ heap()->paged_space(OLD_DATA_SPACE)->ResetUnsweptFreeBytes();
+ heap()->paged_space(OLD_POINTER_SPACE)->ResetUnsweptFreeBytes();
+
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ VerifyEvacuation(heap_);
+ }
+#endif
+}
+
+
+bool MarkCompactCollector::IsSweepingCompleted() {
+ for (int i = 0; i < isolate()->num_sweeper_threads(); i++) {
+ if (!isolate()->sweeper_threads()[i]->SweepingCompleted()) {
+ return false;
+ }
+ }
+
+ if (FLAG_job_based_sweeping) {
+ if (!pending_sweeper_jobs_semaphore_.WaitFor(
+ base::TimeDelta::FromSeconds(0))) {
+ return false;
+ }
+ pending_sweeper_jobs_semaphore_.Signal();
+ }
+
+ return true;
+}
+
+
+void MarkCompactCollector::RefillFreeList(PagedSpace* space) {
+ FreeList* free_list;
+
+ if (space == heap()->old_pointer_space()) {
+ free_list = free_list_old_pointer_space_.get();
+ } else if (space == heap()->old_data_space()) {
+ free_list = free_list_old_data_space_.get();
+ } else {
+ // Any PagedSpace might invoke RefillFreeLists, so we need to make sure
+ // to only refill them for old data and pointer spaces.
+ return;
+ }
+
+ intptr_t freed_bytes = space->free_list()->Concatenate(free_list);
+ space->AddToAccountingStats(freed_bytes);
+ space->DecrementUnsweptFreeBytes(freed_bytes);
+}
+
+
+bool MarkCompactCollector::AreSweeperThreadsActivated() {
+ return isolate()->sweeper_threads() != NULL || FLAG_job_based_sweeping;
+}
+
+
+void Marking::TransferMark(Address old_start, Address new_start) {
+ // This is only used when resizing an object.
+ DCHECK(MemoryChunk::FromAddress(old_start) ==
+ MemoryChunk::FromAddress(new_start));
+
+ if (!heap_->incremental_marking()->IsMarking()) return;
+
+ // If the mark doesn't move, we don't check the color of the object.
+ // It doesn't matter whether the object is black, since it hasn't changed
+ // size, so the adjustment to the live data count will be zero anyway.
+ if (old_start == new_start) return;
+
+ MarkBit new_mark_bit = MarkBitFrom(new_start);
+ MarkBit old_mark_bit = MarkBitFrom(old_start);
+
+#ifdef DEBUG
+ ObjectColor old_color = Color(old_mark_bit);
+#endif
+
+ if (Marking::IsBlack(old_mark_bit)) {
+ old_mark_bit.Clear();
+ DCHECK(IsWhite(old_mark_bit));
+ Marking::MarkBlack(new_mark_bit);
+ return;
+ } else if (Marking::IsGrey(old_mark_bit)) {
+ old_mark_bit.Clear();
+ old_mark_bit.Next().Clear();
+ DCHECK(IsWhite(old_mark_bit));
+ heap_->incremental_marking()->WhiteToGreyAndPush(
+ HeapObject::FromAddress(new_start), new_mark_bit);
+ heap_->incremental_marking()->RestartIfNotMarking();
+ }
+
+#ifdef DEBUG
+ ObjectColor new_color = Color(new_mark_bit);
+ DCHECK(new_color == old_color);
+#endif
+}
+
+
+const char* AllocationSpaceName(AllocationSpace space) {
+ switch (space) {
+ case NEW_SPACE:
+ return "NEW_SPACE";
+ case OLD_POINTER_SPACE:
+ return "OLD_POINTER_SPACE";
+ case OLD_DATA_SPACE:
+ return "OLD_DATA_SPACE";
+ case CODE_SPACE:
+ return "CODE_SPACE";
+ case MAP_SPACE:
+ return "MAP_SPACE";
+ case CELL_SPACE:
+ return "CELL_SPACE";
+ case PROPERTY_CELL_SPACE:
+ return "PROPERTY_CELL_SPACE";
+ case LO_SPACE:
+ return "LO_SPACE";
+ default:
+ UNREACHABLE();
+ }
+
+ return NULL;
+}
+
+
+// Returns zero for pages that have so little fragmentation that it is not
+// worth defragmenting them. Otherwise a positive integer that gives an
+// estimate of fragmentation on an arbitrary scale.
+static int FreeListFragmentation(PagedSpace* space, Page* p) {
+ // If page was not swept then there are no free list items on it.
+ if (!p->WasSwept()) {
+ if (FLAG_trace_fragmentation) {
+ PrintF("%p [%s]: %d bytes live (unswept)\n", reinterpret_cast<void*>(p),
+ AllocationSpaceName(space->identity()), p->LiveBytes());
+ }
+ return 0;
+ }
+
+ PagedSpace::SizeStats sizes;
+ space->ObtainFreeListStatistics(p, &sizes);
+
+ intptr_t ratio;
+ intptr_t ratio_threshold;
+ intptr_t area_size = space->AreaSize();
+ if (space->identity() == CODE_SPACE) {
+ ratio = (sizes.medium_size_ * 10 + sizes.large_size_ * 2) * 100 / area_size;
+ ratio_threshold = 10;
+ } else {
+ ratio = (sizes.small_size_ * 5 + sizes.medium_size_) * 100 / area_size;
+ ratio_threshold = 15;
+ }
+
+ if (FLAG_trace_fragmentation) {
+ PrintF("%p [%s]: %d (%.2f%%) %d (%.2f%%) %d (%.2f%%) %d (%.2f%%) %s\n",
+ reinterpret_cast<void*>(p), AllocationSpaceName(space->identity()),
+ static_cast<int>(sizes.small_size_),
+ static_cast<double>(sizes.small_size_ * 100) / area_size,
+ static_cast<int>(sizes.medium_size_),
+ static_cast<double>(sizes.medium_size_ * 100) / area_size,
+ static_cast<int>(sizes.large_size_),
+ static_cast<double>(sizes.large_size_ * 100) / area_size,
+ static_cast<int>(sizes.huge_size_),
+ static_cast<double>(sizes.huge_size_ * 100) / area_size,
+ (ratio > ratio_threshold) ? "[fragmented]" : "");
+ }
+
+ if (FLAG_always_compact && sizes.Total() != area_size) {
+ return 1;
+ }
+
+ if (ratio <= ratio_threshold) return 0; // Not fragmented.
+
+ return static_cast<int>(ratio - ratio_threshold);
+}
+
+
+void MarkCompactCollector::CollectEvacuationCandidates(PagedSpace* space) {
+ DCHECK(space->identity() == OLD_POINTER_SPACE ||
+ space->identity() == OLD_DATA_SPACE ||
+ space->identity() == CODE_SPACE);
+
+ static const int kMaxMaxEvacuationCandidates = 1000;
+ int number_of_pages = space->CountTotalPages();
+ int max_evacuation_candidates =
+ static_cast<int>(std::sqrt(number_of_pages / 2.0) + 1);
+
+ if (FLAG_stress_compaction || FLAG_always_compact) {
+ max_evacuation_candidates = kMaxMaxEvacuationCandidates;
+ }
+
+ class Candidate {
+ public:
+ Candidate() : fragmentation_(0), page_(NULL) {}
+ Candidate(int f, Page* p) : fragmentation_(f), page_(p) {}
+
+ int fragmentation() { return fragmentation_; }
+ Page* page() { return page_; }
+
+ private:
+ int fragmentation_;
+ Page* page_;
+ };
+
+ enum CompactionMode { COMPACT_FREE_LISTS, REDUCE_MEMORY_FOOTPRINT };
+
+ CompactionMode mode = COMPACT_FREE_LISTS;
+
+ intptr_t reserved = number_of_pages * space->AreaSize();
+ intptr_t over_reserved = reserved - space->SizeOfObjects();
+ static const intptr_t kFreenessThreshold = 50;
+
+ if (reduce_memory_footprint_ && over_reserved >= space->AreaSize()) {
+ // If reduction of memory footprint was requested, we are aggressive
+ // about choosing pages to free. We expect that half-empty pages
+ // are easier to compact so slightly bump the limit.
+ mode = REDUCE_MEMORY_FOOTPRINT;
+ max_evacuation_candidates += 2;
+ }
+
+
+ if (over_reserved > reserved / 3 && over_reserved >= 2 * space->AreaSize()) {
+ // If over-usage is very high (more than a third of the space), we
+ // try to free all mostly empty pages. We expect that almost empty
+ // pages are even easier to compact so bump the limit even more.
+ mode = REDUCE_MEMORY_FOOTPRINT;
+ max_evacuation_candidates *= 2;
+ }
+
+ if (FLAG_trace_fragmentation && mode == REDUCE_MEMORY_FOOTPRINT) {
+ PrintF(
+ "Estimated over reserved memory: %.1f / %.1f MB (threshold %d), "
+ "evacuation candidate limit: %d\n",
+ static_cast<double>(over_reserved) / MB,
+ static_cast<double>(reserved) / MB,
+ static_cast<int>(kFreenessThreshold), max_evacuation_candidates);
+ }
+
+ intptr_t estimated_release = 0;
+
+ Candidate candidates[kMaxMaxEvacuationCandidates];
+
+ max_evacuation_candidates =
+ Min(kMaxMaxEvacuationCandidates, max_evacuation_candidates);
+
+ int count = 0;
+ int fragmentation = 0;
+ Candidate* least = NULL;
+
+ PageIterator it(space);
+ if (it.has_next()) it.next(); // Never compact the first page.
+
+ while (it.has_next()) {
+ Page* p = it.next();
+ p->ClearEvacuationCandidate();
+
+ if (FLAG_stress_compaction) {
+ unsigned int counter = space->heap()->ms_count();
+ uintptr_t page_number = reinterpret_cast<uintptr_t>(p) >> kPageSizeBits;
+ if ((counter & 1) == (page_number & 1)) fragmentation = 1;
+ } else if (mode == REDUCE_MEMORY_FOOTPRINT) {
+ // Don't try to release too many pages.
+ if (estimated_release >= over_reserved) {
+ continue;
+ }
+
+ intptr_t free_bytes = 0;
+
+ if (!p->WasSwept()) {
+ free_bytes = (p->area_size() - p->LiveBytes());
+ } else {
+ PagedSpace::SizeStats sizes;
+ space->ObtainFreeListStatistics(p, &sizes);
+ free_bytes = sizes.Total();
+ }
+
+ int free_pct = static_cast<int>(free_bytes * 100) / p->area_size();
+
+ if (free_pct >= kFreenessThreshold) {
+ estimated_release += free_bytes;
+ fragmentation = free_pct;
+ } else {
+ fragmentation = 0;
+ }
+
+ if (FLAG_trace_fragmentation) {
+ PrintF("%p [%s]: %d (%.2f%%) free %s\n", reinterpret_cast<void*>(p),
+ AllocationSpaceName(space->identity()),
+ static_cast<int>(free_bytes),
+ static_cast<double>(free_bytes * 100) / p->area_size(),
+ (fragmentation > 0) ? "[fragmented]" : "");
+ }
+ } else {
+ fragmentation = FreeListFragmentation(space, p);
+ }
+
+ if (fragmentation != 0) {
+ if (count < max_evacuation_candidates) {
+ candidates[count++] = Candidate(fragmentation, p);
+ } else {
+ if (least == NULL) {
+ for (int i = 0; i < max_evacuation_candidates; i++) {
+ if (least == NULL ||
+ candidates[i].fragmentation() < least->fragmentation()) {
+ least = candidates + i;
+ }
+ }
+ }
+ if (least->fragmentation() < fragmentation) {
+ *least = Candidate(fragmentation, p);
+ least = NULL;
+ }
+ }
+ }
+ }
+
+ for (int i = 0; i < count; i++) {
+ AddEvacuationCandidate(candidates[i].page());
+ }
+
+ if (count > 0 && FLAG_trace_fragmentation) {
+ PrintF("Collected %d evacuation candidates for space %s\n", count,
+ AllocationSpaceName(space->identity()));
+ }
+}
+
+
+void MarkCompactCollector::AbortCompaction() {
+ if (compacting_) {
+ int npages = evacuation_candidates_.length();
+ for (int i = 0; i < npages; i++) {
+ Page* p = evacuation_candidates_[i];
+ slots_buffer_allocator_.DeallocateChain(p->slots_buffer_address());
+ p->ClearEvacuationCandidate();
+ p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION);
+ }
+ compacting_ = false;
+ evacuation_candidates_.Rewind(0);
+ invalidated_code_.Rewind(0);
+ }
+ DCHECK_EQ(0, evacuation_candidates_.length());
+}
+
+
+void MarkCompactCollector::Prepare() {
+ was_marked_incrementally_ = heap()->incremental_marking()->IsMarking();
+
+#ifdef DEBUG
+ DCHECK(state_ == IDLE);
+ state_ = PREPARE_GC;
+#endif
+
+ DCHECK(!FLAG_never_compact || !FLAG_always_compact);
+
+ if (sweeping_in_progress()) {
+ // Instead of waiting we could also abort the sweeper threads here.
+ EnsureSweepingCompleted();
+ }
+
+ // Clear marking bits if incremental marking is aborted.
+ if (was_marked_incrementally_ && abort_incremental_marking_) {
+ heap()->incremental_marking()->Abort();
+ ClearMarkbits();
+ AbortWeakCollections();
+ AbortCompaction();
+ was_marked_incrementally_ = false;
+ }
+
+ // Don't start compaction if we are in the middle of incremental
+ // marking cycle. We did not collect any slots.
+ if (!FLAG_never_compact && !was_marked_incrementally_) {
+ StartCompaction(NON_INCREMENTAL_COMPACTION);
+ }
+
+ PagedSpaces spaces(heap());
+ for (PagedSpace* space = spaces.next(); space != NULL;
+ space = spaces.next()) {
+ space->PrepareForMarkCompact();
+ }
+
+#ifdef VERIFY_HEAP
+ if (!was_marked_incrementally_ && FLAG_verify_heap) {
+ VerifyMarkbitsAreClean();
+ }
+#endif
+}
+
+
+void MarkCompactCollector::Finish() {
+#ifdef DEBUG
+ DCHECK(state_ == SWEEP_SPACES || state_ == RELOCATE_OBJECTS);
+ state_ = IDLE;
+#endif
+ // The stub cache is not traversed during GC; clear the cache to
+ // force lazy re-initialization of it. This must be done after the
+ // GC, because it relies on the new address of certain old space
+ // objects (empty string, illegal builtin).
+ isolate()->stub_cache()->Clear();
+
+ if (have_code_to_deoptimize_) {
+ // Some code objects were marked for deoptimization during the GC.
+ Deoptimizer::DeoptimizeMarkedCode(isolate());
+ have_code_to_deoptimize_ = false;
+ }
+}
+
+
+// -------------------------------------------------------------------------
+// Phase 1: tracing and marking live objects.
+// before: all objects are in normal state.
+// after: a live object's map pointer is marked as '00'.
+
+// Marking all live objects in the heap as part of mark-sweep or mark-compact
+// collection. Before marking, all objects are in their normal state. After
+// marking, live objects' map pointers are marked indicating that the object
+// has been found reachable.
+//
+// The marking algorithm is a (mostly) depth-first (because of possible stack
+// overflow) traversal of the graph of objects reachable from the roots. It
+// uses an explicit stack of pointers rather than recursion. The young
+// generation's inactive ('from') space is used as a marking stack. The
+// objects in the marking stack are the ones that have been reached and marked
+// but their children have not yet been visited.
+//
+// The marking stack can overflow during traversal. In that case, we set an
+// overflow flag. When the overflow flag is set, we continue marking objects
+// reachable from the objects on the marking stack, but no longer push them on
+// the marking stack. Instead, we mark them as both marked and overflowed.
+// When the stack is in the overflowed state, objects marked as overflowed
+// have been reached and marked but their children have not been visited yet.
+// After emptying the marking stack, we clear the overflow flag and traverse
+// the heap looking for objects marked as overflowed, push them on the stack,
+// and continue with marking. This process repeats until all reachable
+// objects have been marked.
+
+void CodeFlusher::ProcessJSFunctionCandidates() {
+ Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kCompileLazy);
+ Object* undefined = isolate_->heap()->undefined_value();
+
+ JSFunction* candidate = jsfunction_candidates_head_;
+ JSFunction* next_candidate;
+ while (candidate != NULL) {
+ next_candidate = GetNextCandidate(candidate);
+ ClearNextCandidate(candidate, undefined);
+
+ SharedFunctionInfo* shared = candidate->shared();
+
+ Code* code = shared->code();
+ MarkBit code_mark = Marking::MarkBitFrom(code);
+ if (!code_mark.Get()) {
+ if (FLAG_trace_code_flushing && shared->is_compiled()) {
+ PrintF("[code-flushing clears: ");
+ shared->ShortPrint();
+ PrintF(" - age: %d]\n", code->GetAge());
+ }
+ shared->set_code(lazy_compile);
+ candidate->set_code(lazy_compile);
+ } else {
+ candidate->set_code(code);
+ }
+
+ // We are in the middle of a GC cycle so the write barrier in the code
+ // setter did not record the slot update and we have to do that manually.
+ Address slot = candidate->address() + JSFunction::kCodeEntryOffset;
+ Code* target = Code::cast(Code::GetObjectFromEntryAddress(slot));
+ isolate_->heap()->mark_compact_collector()->RecordCodeEntrySlot(slot,
+ target);
+
+ Object** shared_code_slot =
+ HeapObject::RawField(shared, SharedFunctionInfo::kCodeOffset);
+ isolate_->heap()->mark_compact_collector()->RecordSlot(
+ shared_code_slot, shared_code_slot, *shared_code_slot);
+
+ candidate = next_candidate;
+ }
+
+ jsfunction_candidates_head_ = NULL;
+}
+
+
+void CodeFlusher::ProcessSharedFunctionInfoCandidates() {
+ Code* lazy_compile = isolate_->builtins()->builtin(Builtins::kCompileLazy);
+
+ SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
+ SharedFunctionInfo* next_candidate;
+ while (candidate != NULL) {
+ next_candidate = GetNextCandidate(candidate);
+ ClearNextCandidate(candidate);
+
+ Code* code = candidate->code();
+ MarkBit code_mark = Marking::MarkBitFrom(code);
+ if (!code_mark.Get()) {
+ if (FLAG_trace_code_flushing && candidate->is_compiled()) {
+ PrintF("[code-flushing clears: ");
+ candidate->ShortPrint();
+ PrintF(" - age: %d]\n", code->GetAge());
+ }
+ candidate->set_code(lazy_compile);
+ }
+
+ Object** code_slot =
+ HeapObject::RawField(candidate, SharedFunctionInfo::kCodeOffset);
+ isolate_->heap()->mark_compact_collector()->RecordSlot(code_slot, code_slot,
+ *code_slot);
+
+ candidate = next_candidate;
+ }
+
+ shared_function_info_candidates_head_ = NULL;
+}
+
+
+void CodeFlusher::ProcessOptimizedCodeMaps() {
+ STATIC_ASSERT(SharedFunctionInfo::kEntryLength == 4);
+
+ SharedFunctionInfo* holder = optimized_code_map_holder_head_;
+ SharedFunctionInfo* next_holder;
+
+ while (holder != NULL) {
+ next_holder = GetNextCodeMap(holder);
+ ClearNextCodeMap(holder);
+
+ FixedArray* code_map = FixedArray::cast(holder->optimized_code_map());
+ int new_length = SharedFunctionInfo::kEntriesStart;
+ int old_length = code_map->length();
+ for (int i = SharedFunctionInfo::kEntriesStart; i < old_length;
+ i += SharedFunctionInfo::kEntryLength) {
+ Code* code =
+ Code::cast(code_map->get(i + SharedFunctionInfo::kCachedCodeOffset));
+ if (!Marking::MarkBitFrom(code).Get()) continue;
+
+ // Move every slot in the entry.
+ for (int j = 0; j < SharedFunctionInfo::kEntryLength; j++) {
+ int dst_index = new_length++;
+ Object** slot = code_map->RawFieldOfElementAt(dst_index);
+ Object* object = code_map->get(i + j);
+ code_map->set(dst_index, object);
+ if (j == SharedFunctionInfo::kOsrAstIdOffset) {
+ DCHECK(object->IsSmi());
+ } else {
+ DCHECK(
+ Marking::IsBlack(Marking::MarkBitFrom(HeapObject::cast(*slot))));
+ isolate_->heap()->mark_compact_collector()->RecordSlot(slot, slot,
+ *slot);
+ }
+ }
+ }
+
+ // Trim the optimized code map if entries have been removed.
+ if (new_length < old_length) {
+ holder->TrimOptimizedCodeMap(old_length - new_length);
+ }
+
+ holder = next_holder;
+ }
+
+ optimized_code_map_holder_head_ = NULL;
+}
+
+
+void CodeFlusher::EvictCandidate(SharedFunctionInfo* shared_info) {
+ // Make sure previous flushing decisions are revisited.
+ isolate_->heap()->incremental_marking()->RecordWrites(shared_info);
+
+ if (FLAG_trace_code_flushing) {
+ PrintF("[code-flushing abandons function-info: ");
+ shared_info->ShortPrint();
+ PrintF("]\n");
+ }
+
+ SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
+ SharedFunctionInfo* next_candidate;
+ if (candidate == shared_info) {
+ next_candidate = GetNextCandidate(shared_info);
+ shared_function_info_candidates_head_ = next_candidate;
+ ClearNextCandidate(shared_info);
+ } else {
+ while (candidate != NULL) {
+ next_candidate = GetNextCandidate(candidate);
+
+ if (next_candidate == shared_info) {
+ next_candidate = GetNextCandidate(shared_info);
+ SetNextCandidate(candidate, next_candidate);
+ ClearNextCandidate(shared_info);
+ break;
+ }
+
+ candidate = next_candidate;
+ }
+ }
+}
+
+
+void CodeFlusher::EvictCandidate(JSFunction* function) {
+ DCHECK(!function->next_function_link()->IsUndefined());
+ Object* undefined = isolate_->heap()->undefined_value();
+
+ // Make sure previous flushing decisions are revisited.
+ isolate_->heap()->incremental_marking()->RecordWrites(function);
+ isolate_->heap()->incremental_marking()->RecordWrites(function->shared());
+
+ if (FLAG_trace_code_flushing) {
+ PrintF("[code-flushing abandons closure: ");
+ function->shared()->ShortPrint();
+ PrintF("]\n");
+ }
+
+ JSFunction* candidate = jsfunction_candidates_head_;
+ JSFunction* next_candidate;
+ if (candidate == function) {
+ next_candidate = GetNextCandidate(function);
+ jsfunction_candidates_head_ = next_candidate;
+ ClearNextCandidate(function, undefined);
+ } else {
+ while (candidate != NULL) {
+ next_candidate = GetNextCandidate(candidate);
+
+ if (next_candidate == function) {
+ next_candidate = GetNextCandidate(function);
+ SetNextCandidate(candidate, next_candidate);
+ ClearNextCandidate(function, undefined);
+ break;
+ }
+
+ candidate = next_candidate;
+ }
+ }
+}
+
+
+void CodeFlusher::EvictOptimizedCodeMap(SharedFunctionInfo* code_map_holder) {
+ DCHECK(!FixedArray::cast(code_map_holder->optimized_code_map())
+ ->get(SharedFunctionInfo::kNextMapIndex)
+ ->IsUndefined());
+
+ // Make sure previous flushing decisions are revisited.
+ isolate_->heap()->incremental_marking()->RecordWrites(code_map_holder);
+
+ if (FLAG_trace_code_flushing) {
+ PrintF("[code-flushing abandons code-map: ");
+ code_map_holder->ShortPrint();
+ PrintF("]\n");
+ }
+
+ SharedFunctionInfo* holder = optimized_code_map_holder_head_;
+ SharedFunctionInfo* next_holder;
+ if (holder == code_map_holder) {
+ next_holder = GetNextCodeMap(code_map_holder);
+ optimized_code_map_holder_head_ = next_holder;
+ ClearNextCodeMap(code_map_holder);
+ } else {
+ while (holder != NULL) {
+ next_holder = GetNextCodeMap(holder);
+
+ if (next_holder == code_map_holder) {
+ next_holder = GetNextCodeMap(code_map_holder);
+ SetNextCodeMap(holder, next_holder);
+ ClearNextCodeMap(code_map_holder);
+ break;
+ }
+
+ holder = next_holder;
+ }
+ }
+}
+
+
+void CodeFlusher::EvictJSFunctionCandidates() {
+ JSFunction* candidate = jsfunction_candidates_head_;
+ JSFunction* next_candidate;
+ while (candidate != NULL) {
+ next_candidate = GetNextCandidate(candidate);
+ EvictCandidate(candidate);
+ candidate = next_candidate;
+ }
+ DCHECK(jsfunction_candidates_head_ == NULL);
+}
+
+
+void CodeFlusher::EvictSharedFunctionInfoCandidates() {
+ SharedFunctionInfo* candidate = shared_function_info_candidates_head_;
+ SharedFunctionInfo* next_candidate;
+ while (candidate != NULL) {
+ next_candidate = GetNextCandidate(candidate);
+ EvictCandidate(candidate);
+ candidate = next_candidate;
+ }
+ DCHECK(shared_function_info_candidates_head_ == NULL);
+}
+
+
+void CodeFlusher::EvictOptimizedCodeMaps() {
+ SharedFunctionInfo* holder = optimized_code_map_holder_head_;
+ SharedFunctionInfo* next_holder;
+ while (holder != NULL) {
+ next_holder = GetNextCodeMap(holder);
+ EvictOptimizedCodeMap(holder);
+ holder = next_holder;
+ }
+ DCHECK(optimized_code_map_holder_head_ == NULL);
+}
+
+
+void CodeFlusher::IteratePointersToFromSpace(ObjectVisitor* v) {
+ Heap* heap = isolate_->heap();
+
+ JSFunction** slot = &jsfunction_candidates_head_;
+ JSFunction* candidate = jsfunction_candidates_head_;
+ while (candidate != NULL) {
+ if (heap->InFromSpace(candidate)) {
+ v->VisitPointer(reinterpret_cast<Object**>(slot));
+ }
+ candidate = GetNextCandidate(*slot);
+ slot = GetNextCandidateSlot(*slot);
+ }
+}
+
+
+MarkCompactCollector::~MarkCompactCollector() {
+ if (code_flusher_ != NULL) {
+ delete code_flusher_;
+ code_flusher_ = NULL;
+ }
+}
+
+
+static inline HeapObject* ShortCircuitConsString(Object** p) {
+ // Optimization: If the heap object pointed to by p is a non-internalized
+ // cons string whose right substring is HEAP->empty_string, update
+ // it in place to its left substring. Return the updated value.
+ //
+ // Here we assume that if we change *p, we replace it with a heap object
+ // (i.e., the left substring of a cons string is always a heap object).
+ //
+ // The check performed is:
+ // object->IsConsString() && !object->IsInternalizedString() &&
+ // (ConsString::cast(object)->second() == HEAP->empty_string())
+ // except the maps for the object and its possible substrings might be
+ // marked.
+ HeapObject* object = HeapObject::cast(*p);
+ if (!FLAG_clever_optimizations) return object;
+ Map* map = object->map();
+ InstanceType type = map->instance_type();
+ if (!IsShortcutCandidate(type)) return object;
+
+ Object* second = reinterpret_cast<ConsString*>(object)->second();
+ Heap* heap = map->GetHeap();
+ if (second != heap->empty_string()) {
+ return object;
+ }
+
+ // Since we don't have the object's start, it is impossible to update the
+ // page dirty marks. Therefore, we only replace the string with its left
+ // substring when page dirty marks do not change.
+ Object* first = reinterpret_cast<ConsString*>(object)->first();
+ if (!heap->InNewSpace(object) && heap->InNewSpace(first)) return object;
+
+ *p = first;
+ return HeapObject::cast(first);
+}
+
+
+class MarkCompactMarkingVisitor
+ : public StaticMarkingVisitor<MarkCompactMarkingVisitor> {
+ public:
+ static void ObjectStatsVisitBase(StaticVisitorBase::VisitorId id, Map* map,
+ HeapObject* obj);
+
+ static void ObjectStatsCountFixedArray(
+ FixedArrayBase* fixed_array, FixedArraySubInstanceType fast_type,
+ FixedArraySubInstanceType dictionary_type);
+
+ template <MarkCompactMarkingVisitor::VisitorId id>
+ class ObjectStatsTracker {
+ public:
+ static inline void Visit(Map* map, HeapObject* obj);
+ };
+
+ static void Initialize();
+
+ INLINE(static void VisitPointer(Heap* heap, Object** p)) {
+ MarkObjectByPointer(heap->mark_compact_collector(), p, p);
+ }
+
+ INLINE(static void VisitPointers(Heap* heap, Object** start, Object** end)) {
+ // Mark all objects pointed to in [start, end).
+ const int kMinRangeForMarkingRecursion = 64;
+ if (end - start >= kMinRangeForMarkingRecursion) {
+ if (VisitUnmarkedObjects(heap, start, end)) return;
+ // We are close to a stack overflow, so just mark the objects.
+ }
+ MarkCompactCollector* collector = heap->mark_compact_collector();
+ for (Object** p = start; p < end; p++) {
+ MarkObjectByPointer(collector, start, p);
+ }
+ }
+
+ // Marks the object black and pushes it on the marking stack.
+ INLINE(static void MarkObject(Heap* heap, HeapObject* object)) {
+ MarkBit mark = Marking::MarkBitFrom(object);
+ heap->mark_compact_collector()->MarkObject(object, mark);
+ }
+
+ // Marks the object black without pushing it on the marking stack.
+ // Returns true if object needed marking and false otherwise.
+ INLINE(static bool MarkObjectWithoutPush(Heap* heap, HeapObject* object)) {
+ MarkBit mark_bit = Marking::MarkBitFrom(object);
+ if (!mark_bit.Get()) {
+ heap->mark_compact_collector()->SetMark(object, mark_bit);
+ return true;
+ }
+ return false;
+ }
+
+ // Mark object pointed to by p.
+ INLINE(static void MarkObjectByPointer(MarkCompactCollector* collector,
+ Object** anchor_slot, Object** p)) {
+ if (!(*p)->IsHeapObject()) return;
+ HeapObject* object = ShortCircuitConsString(p);
+ collector->RecordSlot(anchor_slot, p, object);
+ MarkBit mark = Marking::MarkBitFrom(object);
+ collector->MarkObject(object, mark);
+ }
+
+
+ // Visit an unmarked object.
+ INLINE(static void VisitUnmarkedObject(MarkCompactCollector* collector,
+ HeapObject* obj)) {
+#ifdef DEBUG
+ DCHECK(collector->heap()->Contains(obj));
+ DCHECK(!collector->heap()->mark_compact_collector()->IsMarked(obj));
+#endif
+ Map* map = obj->map();
+ Heap* heap = obj->GetHeap();
+ MarkBit mark = Marking::MarkBitFrom(obj);
+ heap->mark_compact_collector()->SetMark(obj, mark);
+ // Mark the map pointer and the body.
+ MarkBit map_mark = Marking::MarkBitFrom(map);
+ heap->mark_compact_collector()->MarkObject(map, map_mark);
+ IterateBody(map, obj);
+ }
+
+ // Visit all unmarked objects pointed to by [start, end).
+ // Returns false if the operation fails (lack of stack space).
+ INLINE(static bool VisitUnmarkedObjects(Heap* heap, Object** start,
+ Object** end)) {
+ // Return false is we are close to the stack limit.
+ StackLimitCheck check(heap->isolate());
+ if (check.HasOverflowed()) return false;
+
+ MarkCompactCollector* collector = heap->mark_compact_collector();
+ // Visit the unmarked objects.
+ for (Object** p = start; p < end; p++) {
+ Object* o = *p;
+ if (!o->IsHeapObject()) continue;
+ collector->RecordSlot(start, p, o);
+ HeapObject* obj = HeapObject::cast(o);
+ MarkBit mark = Marking::MarkBitFrom(obj);
+ if (mark.Get()) continue;
+ VisitUnmarkedObject(collector, obj);
+ }
+ return true;
+ }
+
+ private:
+ template <int id>
+ static inline void TrackObjectStatsAndVisit(Map* map, HeapObject* obj);
+
+ // Code flushing support.
+
+ static const int kRegExpCodeThreshold = 5;
+
+ static void UpdateRegExpCodeAgeAndFlush(Heap* heap, JSRegExp* re,
+ bool is_one_byte) {
+ // Make sure that the fixed array is in fact initialized on the RegExp.
+ // We could potentially trigger a GC when initializing the RegExp.
+ if (HeapObject::cast(re->data())->map()->instance_type() !=
+ FIXED_ARRAY_TYPE)
+ return;
+
+ // Make sure this is a RegExp that actually contains code.
+ if (re->TypeTag() != JSRegExp::IRREGEXP) return;
+
+ Object* code = re->DataAt(JSRegExp::code_index(is_one_byte));
+ if (!code->IsSmi() &&
+ HeapObject::cast(code)->map()->instance_type() == CODE_TYPE) {
+ // Save a copy that can be reinstated if we need the code again.
+ re->SetDataAt(JSRegExp::saved_code_index(is_one_byte), code);
+
+ // Saving a copy might create a pointer into compaction candidate
+ // that was not observed by marker. This might happen if JSRegExp data
+ // was marked through the compilation cache before marker reached JSRegExp
+ // object.
+ FixedArray* data = FixedArray::cast(re->data());
+ Object** slot =
+ data->data_start() + JSRegExp::saved_code_index(is_one_byte);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, code);
+
+ // Set a number in the 0-255 range to guarantee no smi overflow.
+ re->SetDataAt(JSRegExp::code_index(is_one_byte),
+ Smi::FromInt(heap->sweep_generation() & 0xff));
+ } else if (code->IsSmi()) {
+ int value = Smi::cast(code)->value();
+ // The regexp has not been compiled yet or there was a compilation error.
+ if (value == JSRegExp::kUninitializedValue ||
+ value == JSRegExp::kCompilationErrorValue) {
+ return;
+ }
+
+ // Check if we should flush now.
+ if (value == ((heap->sweep_generation() - kRegExpCodeThreshold) & 0xff)) {
+ re->SetDataAt(JSRegExp::code_index(is_one_byte),
+ Smi::FromInt(JSRegExp::kUninitializedValue));
+ re->SetDataAt(JSRegExp::saved_code_index(is_one_byte),
+ Smi::FromInt(JSRegExp::kUninitializedValue));
+ }
+ }
+ }
+
+
+ // Works by setting the current sweep_generation (as a smi) in the
+ // code object place in the data array of the RegExp and keeps a copy
+ // around that can be reinstated if we reuse the RegExp before flushing.
+ // If we did not use the code for kRegExpCodeThreshold mark sweep GCs
+ // we flush the code.
+ static void VisitRegExpAndFlushCode(Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+ MarkCompactCollector* collector = heap->mark_compact_collector();
+ if (!collector->is_code_flushing_enabled()) {
+ VisitJSRegExp(map, object);
+ return;
+ }
+ JSRegExp* re = reinterpret_cast<JSRegExp*>(object);
+ // Flush code or set age on both one byte and two byte code.
+ UpdateRegExpCodeAgeAndFlush(heap, re, true);
+ UpdateRegExpCodeAgeAndFlush(heap, re, false);
+ // Visit the fields of the RegExp, including the updated FixedArray.
+ VisitJSRegExp(map, object);
+ }
+
+ static VisitorDispatchTable<Callback> non_count_table_;
+};
+
+
+void MarkCompactMarkingVisitor::ObjectStatsCountFixedArray(
+ FixedArrayBase* fixed_array, FixedArraySubInstanceType fast_type,
+ FixedArraySubInstanceType dictionary_type) {
+ Heap* heap = fixed_array->map()->GetHeap();
+ if (fixed_array->map() != heap->fixed_cow_array_map() &&
+ fixed_array->map() != heap->fixed_double_array_map() &&
+ fixed_array != heap->empty_fixed_array()) {
+ if (fixed_array->IsDictionary()) {
+ heap->RecordFixedArraySubTypeStats(dictionary_type, fixed_array->Size());
+ } else {
+ heap->RecordFixedArraySubTypeStats(fast_type, fixed_array->Size());
+ }
+ }
+}
+
+
+void MarkCompactMarkingVisitor::ObjectStatsVisitBase(
+ MarkCompactMarkingVisitor::VisitorId id, Map* map, HeapObject* obj) {
+ Heap* heap = map->GetHeap();
+ int object_size = obj->Size();
+ heap->RecordObjectStats(map->instance_type(), object_size);
+ non_count_table_.GetVisitorById(id)(map, obj);
+ if (obj->IsJSObject()) {
+ JSObject* object = JSObject::cast(obj);
+ ObjectStatsCountFixedArray(object->elements(), DICTIONARY_ELEMENTS_SUB_TYPE,
+ FAST_ELEMENTS_SUB_TYPE);
+ ObjectStatsCountFixedArray(object->properties(),
+ DICTIONARY_PROPERTIES_SUB_TYPE,
+ FAST_PROPERTIES_SUB_TYPE);
+ }
+}
+
+
+template <MarkCompactMarkingVisitor::VisitorId id>
+void MarkCompactMarkingVisitor::ObjectStatsTracker<id>::Visit(Map* map,
+ HeapObject* obj) {
+ ObjectStatsVisitBase(id, map, obj);
+}
+
+
+template <>
+class MarkCompactMarkingVisitor::ObjectStatsTracker<
+ MarkCompactMarkingVisitor::kVisitMap> {
+ public:
+ static inline void Visit(Map* map, HeapObject* obj) {
+ Heap* heap = map->GetHeap();
+ Map* map_obj = Map::cast(obj);
+ DCHECK(map->instance_type() == MAP_TYPE);
+ DescriptorArray* array = map_obj->instance_descriptors();
+ if (map_obj->owns_descriptors() &&
+ array != heap->empty_descriptor_array()) {
+ int fixed_array_size = array->Size();
+ heap->RecordFixedArraySubTypeStats(DESCRIPTOR_ARRAY_SUB_TYPE,
+ fixed_array_size);
+ }
+ if (map_obj->HasTransitionArray()) {
+ int fixed_array_size = map_obj->transitions()->Size();
+ heap->RecordFixedArraySubTypeStats(TRANSITION_ARRAY_SUB_TYPE,
+ fixed_array_size);
+ }
+ if (map_obj->has_code_cache()) {
+ CodeCache* cache = CodeCache::cast(map_obj->code_cache());
+ heap->RecordFixedArraySubTypeStats(MAP_CODE_CACHE_SUB_TYPE,
+ cache->default_cache()->Size());
+ if (!cache->normal_type_cache()->IsUndefined()) {
+ heap->RecordFixedArraySubTypeStats(
+ MAP_CODE_CACHE_SUB_TYPE,
+ FixedArray::cast(cache->normal_type_cache())->Size());
+ }
+ }
+ ObjectStatsVisitBase(kVisitMap, map, obj);
+ }
+};
+
+
+template <>
+class MarkCompactMarkingVisitor::ObjectStatsTracker<
+ MarkCompactMarkingVisitor::kVisitCode> {
+ public:
+ static inline void Visit(Map* map, HeapObject* obj) {
+ Heap* heap = map->GetHeap();
+ int object_size = obj->Size();
+ DCHECK(map->instance_type() == CODE_TYPE);
+ Code* code_obj = Code::cast(obj);
+ heap->RecordCodeSubTypeStats(code_obj->kind(), code_obj->GetRawAge(),
+ object_size);
+ ObjectStatsVisitBase(kVisitCode, map, obj);
+ }
+};
+
+
+template <>
+class MarkCompactMarkingVisitor::ObjectStatsTracker<
+ MarkCompactMarkingVisitor::kVisitSharedFunctionInfo> {
+ public:
+ static inline void Visit(Map* map, HeapObject* obj) {
+ Heap* heap = map->GetHeap();
+ SharedFunctionInfo* sfi = SharedFunctionInfo::cast(obj);
+ if (sfi->scope_info() != heap->empty_fixed_array()) {
+ heap->RecordFixedArraySubTypeStats(
+ SCOPE_INFO_SUB_TYPE, FixedArray::cast(sfi->scope_info())->Size());
+ }
+ ObjectStatsVisitBase(kVisitSharedFunctionInfo, map, obj);
+ }
+};
+
+
+template <>
+class MarkCompactMarkingVisitor::ObjectStatsTracker<
+ MarkCompactMarkingVisitor::kVisitFixedArray> {
+ public:
+ static inline void Visit(Map* map, HeapObject* obj) {
+ Heap* heap = map->GetHeap();
+ FixedArray* fixed_array = FixedArray::cast(obj);
+ if (fixed_array == heap->string_table()) {
+ heap->RecordFixedArraySubTypeStats(STRING_TABLE_SUB_TYPE,
+ fixed_array->Size());
+ }
+ ObjectStatsVisitBase(kVisitFixedArray, map, obj);
+ }
+};
+
+
+void MarkCompactMarkingVisitor::Initialize() {
+ StaticMarkingVisitor<MarkCompactMarkingVisitor>::Initialize();
+
+ table_.Register(kVisitJSRegExp, &VisitRegExpAndFlushCode);
+
+ if (FLAG_track_gc_object_stats) {
+ // Copy the visitor table to make call-through possible.
+ non_count_table_.CopyFrom(&table_);
+#define VISITOR_ID_COUNT_FUNCTION(id) \
+ table_.Register(kVisit##id, ObjectStatsTracker<kVisit##id>::Visit);
+ VISITOR_ID_LIST(VISITOR_ID_COUNT_FUNCTION)
+#undef VISITOR_ID_COUNT_FUNCTION
+ }
+}
+
+
+VisitorDispatchTable<MarkCompactMarkingVisitor::Callback>
+ MarkCompactMarkingVisitor::non_count_table_;
+
+
+class CodeMarkingVisitor : public ThreadVisitor {
+ public:
+ explicit CodeMarkingVisitor(MarkCompactCollector* collector)
+ : collector_(collector) {}
+
+ void VisitThread(Isolate* isolate, ThreadLocalTop* top) {
+ collector_->PrepareThreadForCodeFlushing(isolate, top);
+ }
+
+ private:
+ MarkCompactCollector* collector_;
+};
+
+
+class SharedFunctionInfoMarkingVisitor : public ObjectVisitor {
+ public:
+ explicit SharedFunctionInfoMarkingVisitor(MarkCompactCollector* collector)
+ : collector_(collector) {}
+
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++) VisitPointer(p);
+ }
+
+ void VisitPointer(Object** slot) {
+ Object* obj = *slot;
+ if (obj->IsSharedFunctionInfo()) {
+ SharedFunctionInfo* shared = reinterpret_cast<SharedFunctionInfo*>(obj);
+ MarkBit shared_mark = Marking::MarkBitFrom(shared);
+ MarkBit code_mark = Marking::MarkBitFrom(shared->code());
+ collector_->MarkObject(shared->code(), code_mark);
+ collector_->MarkObject(shared, shared_mark);
+ }
+ }
+
+ private:
+ MarkCompactCollector* collector_;
+};
+
+
+void MarkCompactCollector::PrepareThreadForCodeFlushing(Isolate* isolate,
+ ThreadLocalTop* top) {
+ for (StackFrameIterator it(isolate, top); !it.done(); it.Advance()) {
+ // Note: for the frame that has a pending lazy deoptimization
+ // StackFrame::unchecked_code will return a non-optimized code object for
+ // the outermost function and StackFrame::LookupCode will return
+ // actual optimized code object.
+ StackFrame* frame = it.frame();
+ Code* code = frame->unchecked_code();
+ MarkBit code_mark = Marking::MarkBitFrom(code);
+ MarkObject(code, code_mark);
+ if (frame->is_optimized()) {
+ MarkCompactMarkingVisitor::MarkInlinedFunctionsCode(heap(),
+ frame->LookupCode());
+ }
+ }
+}
+
+
+void MarkCompactCollector::PrepareForCodeFlushing() {
+ // Enable code flushing for non-incremental cycles.
+ if (FLAG_flush_code && !FLAG_flush_code_incrementally) {
+ EnableCodeFlushing(!was_marked_incrementally_);
+ }
+
+ // If code flushing is disabled, there is no need to prepare for it.
+ if (!is_code_flushing_enabled()) return;
+
+ // Ensure that empty descriptor array is marked. Method MarkDescriptorArray
+ // relies on it being marked before any other descriptor array.
+ HeapObject* descriptor_array = heap()->empty_descriptor_array();
+ MarkBit descriptor_array_mark = Marking::MarkBitFrom(descriptor_array);
+ MarkObject(descriptor_array, descriptor_array_mark);
+
+ // Make sure we are not referencing the code from the stack.
+ DCHECK(this == heap()->mark_compact_collector());
+ PrepareThreadForCodeFlushing(heap()->isolate(),
+ heap()->isolate()->thread_local_top());
+
+ // Iterate the archived stacks in all threads to check if
+ // the code is referenced.
+ CodeMarkingVisitor code_marking_visitor(this);
+ heap()->isolate()->thread_manager()->IterateArchivedThreads(
+ &code_marking_visitor);
+
+ SharedFunctionInfoMarkingVisitor visitor(this);
+ heap()->isolate()->compilation_cache()->IterateFunctions(&visitor);
+ heap()->isolate()->handle_scope_implementer()->Iterate(&visitor);
+
+ ProcessMarkingDeque();
+}
+
+
+// Visitor class for marking heap roots.
+class RootMarkingVisitor : public ObjectVisitor {
+ public:
+ explicit RootMarkingVisitor(Heap* heap)
+ : collector_(heap->mark_compact_collector()) {}
+
+ void VisitPointer(Object** p) { MarkObjectByPointer(p); }
+
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++) MarkObjectByPointer(p);
+ }
+
+ // Skip the weak next code link in a code object, which is visited in
+ // ProcessTopOptimizedFrame.
+ void VisitNextCodeLink(Object** p) {}
+
+ private:
+ void MarkObjectByPointer(Object** p) {
+ if (!(*p)->IsHeapObject()) return;
+
+ // Replace flat cons strings in place.
+ HeapObject* object = ShortCircuitConsString(p);
+ MarkBit mark_bit = Marking::MarkBitFrom(object);
+ if (mark_bit.Get()) return;
+
+ Map* map = object->map();
+ // Mark the object.
+ collector_->SetMark(object, mark_bit);
+
+ // Mark the map pointer and body, and push them on the marking stack.
+ MarkBit map_mark = Marking::MarkBitFrom(map);
+ collector_->MarkObject(map, map_mark);
+ MarkCompactMarkingVisitor::IterateBody(map, object);
+
+ // Mark all the objects reachable from the map and body. May leave
+ // overflowed objects in the heap.
+ collector_->EmptyMarkingDeque();
+ }
+
+ MarkCompactCollector* collector_;
+};
+
+
+// Helper class for pruning the string table.
+template <bool finalize_external_strings>
+class StringTableCleaner : public ObjectVisitor {
+ public:
+ explicit StringTableCleaner(Heap* heap) : heap_(heap), pointers_removed_(0) {}
+
+ virtual void VisitPointers(Object** start, Object** end) {
+ // Visit all HeapObject pointers in [start, end).
+ for (Object** p = start; p < end; p++) {
+ Object* o = *p;
+ if (o->IsHeapObject() &&
+ !Marking::MarkBitFrom(HeapObject::cast(o)).Get()) {
+ if (finalize_external_strings) {
+ DCHECK(o->IsExternalString());
+ heap_->FinalizeExternalString(String::cast(*p));
+ } else {
+ pointers_removed_++;
+ }
+ // Set the entry to the_hole_value (as deleted).
+ *p = heap_->the_hole_value();
+ }
+ }
+ }
+
+ int PointersRemoved() {
+ DCHECK(!finalize_external_strings);
+ return pointers_removed_;
+ }
+
+ private:
+ Heap* heap_;
+ int pointers_removed_;
+};
+
+
+typedef StringTableCleaner<false> InternalizedStringTableCleaner;
+typedef StringTableCleaner<true> ExternalStringTableCleaner;
+
+
+// Implementation of WeakObjectRetainer for mark compact GCs. All marked objects
+// are retained.
+class MarkCompactWeakObjectRetainer : public WeakObjectRetainer {
+ public:
+ virtual Object* RetainAs(Object* object) {
+ if (Marking::MarkBitFrom(HeapObject::cast(object)).Get()) {
+ return object;
+ } else if (object->IsAllocationSite() &&
+ !(AllocationSite::cast(object)->IsZombie())) {
+ // "dead" AllocationSites need to live long enough for a traversal of new
+ // space. These sites get a one-time reprieve.
+ AllocationSite* site = AllocationSite::cast(object);
+ site->MarkZombie();
+ site->GetHeap()->mark_compact_collector()->MarkAllocationSite(site);
+ return object;
+ } else {
+ return NULL;
+ }
+ }
+};
+
+
+// Fill the marking stack with overflowed objects returned by the given
+// iterator. Stop when the marking stack is filled or the end of the space
+// is reached, whichever comes first.
+template <class T>
+static void DiscoverGreyObjectsWithIterator(Heap* heap,
+ MarkingDeque* marking_deque,
+ T* it) {
+ // The caller should ensure that the marking stack is initially not full,
+ // so that we don't waste effort pointlessly scanning for objects.
+ DCHECK(!marking_deque->IsFull());
+
+ Map* filler_map = heap->one_pointer_filler_map();
+ for (HeapObject* object = it->Next(); object != NULL; object = it->Next()) {
+ MarkBit markbit = Marking::MarkBitFrom(object);
+ if ((object->map() != filler_map) && Marking::IsGrey(markbit)) {
+ Marking::GreyToBlack(markbit);
+ MemoryChunk::IncrementLiveBytesFromGC(object->address(), object->Size());
+ marking_deque->PushBlack(object);
+ if (marking_deque->IsFull()) return;
+ }
+ }
+}
+
+
+static inline int MarkWordToObjectStarts(uint32_t mark_bits, int* starts);
+
+
+static void DiscoverGreyObjectsOnPage(MarkingDeque* marking_deque,
+ MemoryChunk* p) {
+ DCHECK(!marking_deque->IsFull());
+ DCHECK(strcmp(Marking::kWhiteBitPattern, "00") == 0);
+ DCHECK(strcmp(Marking::kBlackBitPattern, "10") == 0);
+ DCHECK(strcmp(Marking::kGreyBitPattern, "11") == 0);
+ DCHECK(strcmp(Marking::kImpossibleBitPattern, "01") == 0);
+
+ for (MarkBitCellIterator it(p); !it.Done(); it.Advance()) {
+ Address cell_base = it.CurrentCellBase();
+ MarkBit::CellType* cell = it.CurrentCell();
+
+ const MarkBit::CellType current_cell = *cell;
+ if (current_cell == 0) continue;
+
+ MarkBit::CellType grey_objects;
+ if (it.HasNext()) {
+ const MarkBit::CellType next_cell = *(cell + 1);
+ grey_objects = current_cell & ((current_cell >> 1) |
+ (next_cell << (Bitmap::kBitsPerCell - 1)));
+ } else {
+ grey_objects = current_cell & (current_cell >> 1);
+ }
+
+ int offset = 0;
+ while (grey_objects != 0) {
+ int trailing_zeros = base::bits::CountTrailingZeros32(grey_objects);
+ grey_objects >>= trailing_zeros;
+ offset += trailing_zeros;
+ MarkBit markbit(cell, 1 << offset, false);
+ DCHECK(Marking::IsGrey(markbit));
+ Marking::GreyToBlack(markbit);
+ Address addr = cell_base + offset * kPointerSize;
+ HeapObject* object = HeapObject::FromAddress(addr);
+ MemoryChunk::IncrementLiveBytesFromGC(object->address(), object->Size());
+ marking_deque->PushBlack(object);
+ if (marking_deque->IsFull()) return;
+ offset += 2;
+ grey_objects >>= 2;
+ }
+
+ grey_objects >>= (Bitmap::kBitsPerCell - 1);
+ }
+}
+
+
+int MarkCompactCollector::DiscoverAndEvacuateBlackObjectsOnPage(
+ NewSpace* new_space, NewSpacePage* p) {
+ DCHECK(strcmp(Marking::kWhiteBitPattern, "00") == 0);
+ DCHECK(strcmp(Marking::kBlackBitPattern, "10") == 0);
+ DCHECK(strcmp(Marking::kGreyBitPattern, "11") == 0);
+ DCHECK(strcmp(Marking::kImpossibleBitPattern, "01") == 0);
+
+ MarkBit::CellType* cells = p->markbits()->cells();
+ int survivors_size = 0;
+
+ for (MarkBitCellIterator it(p); !it.Done(); it.Advance()) {
+ Address cell_base = it.CurrentCellBase();
+ MarkBit::CellType* cell = it.CurrentCell();
+
+ MarkBit::CellType current_cell = *cell;
+ if (current_cell == 0) continue;
+
+ int offset = 0;
+ while (current_cell != 0) {
+ int trailing_zeros = base::bits::CountTrailingZeros32(current_cell);
+ current_cell >>= trailing_zeros;
+ offset += trailing_zeros;
+ Address address = cell_base + offset * kPointerSize;
+ HeapObject* object = HeapObject::FromAddress(address);
+
+ int size = object->Size();
+ survivors_size += size;
+
+ Heap::UpdateAllocationSiteFeedback(object, Heap::RECORD_SCRATCHPAD_SLOT);
+
+ offset++;
+ current_cell >>= 1;
+
+ // TODO(hpayer): Refactor EvacuateObject and call this function instead.
+ if (heap()->ShouldBePromoted(object->address(), size) &&
+ TryPromoteObject(object, size)) {
+ continue;
+ }
+
+ AllocationResult allocation = new_space->AllocateRaw(size);
+ if (allocation.IsRetry()) {
+ if (!new_space->AddFreshPage()) {
+ // Shouldn't happen. We are sweeping linearly, and to-space
+ // has the same number of pages as from-space, so there is
+ // always room.
+ UNREACHABLE();
+ }
+ allocation = new_space->AllocateRaw(size);
+ DCHECK(!allocation.IsRetry());
+ }
+ Object* target = allocation.ToObjectChecked();
+
+ MigrateObject(HeapObject::cast(target), object, size, NEW_SPACE);
+ heap()->IncrementSemiSpaceCopiedObjectSize(size);
+ }
+ *cells = 0;
+ }
+ return survivors_size;
+}
+
+
+static void DiscoverGreyObjectsInSpace(Heap* heap, MarkingDeque* marking_deque,
+ PagedSpace* space) {
+ PageIterator it(space);
+ while (it.has_next()) {
+ Page* p = it.next();
+ DiscoverGreyObjectsOnPage(marking_deque, p);
+ if (marking_deque->IsFull()) return;
+ }
+}
+
+
+static void DiscoverGreyObjectsInNewSpace(Heap* heap,
+ MarkingDeque* marking_deque) {
+ NewSpace* space = heap->new_space();
+ NewSpacePageIterator it(space->bottom(), space->top());
+ while (it.has_next()) {
+ NewSpacePage* page = it.next();
+ DiscoverGreyObjectsOnPage(marking_deque, page);
+ if (marking_deque->IsFull()) return;
+ }
+}
+
+
+bool MarkCompactCollector::IsUnmarkedHeapObject(Object** p) {
+ Object* o = *p;
+ if (!o->IsHeapObject()) return false;
+ HeapObject* heap_object = HeapObject::cast(o);
+ MarkBit mark = Marking::MarkBitFrom(heap_object);
+ return !mark.Get();
+}
+
+
+bool MarkCompactCollector::IsUnmarkedHeapObjectWithHeap(Heap* heap,
+ Object** p) {
+ Object* o = *p;
+ DCHECK(o->IsHeapObject());
+ HeapObject* heap_object = HeapObject::cast(o);
+ MarkBit mark = Marking::MarkBitFrom(heap_object);
+ return !mark.Get();
+}
+
+
+void MarkCompactCollector::MarkStringTable(RootMarkingVisitor* visitor) {
+ StringTable* string_table = heap()->string_table();
+ // Mark the string table itself.
+ MarkBit string_table_mark = Marking::MarkBitFrom(string_table);
+ if (!string_table_mark.Get()) {
+ // String table could have already been marked by visiting the handles list.
+ SetMark(string_table, string_table_mark);
+ }
+ // Explicitly mark the prefix.
+ string_table->IteratePrefix(visitor);
+ ProcessMarkingDeque();
+}
+
+
+void MarkCompactCollector::MarkAllocationSite(AllocationSite* site) {
+ MarkBit mark_bit = Marking::MarkBitFrom(site);
+ SetMark(site, mark_bit);
+}
+
+
+void MarkCompactCollector::MarkRoots(RootMarkingVisitor* visitor) {
+ // Mark the heap roots including global variables, stack variables,
+ // etc., and all objects reachable from them.
+ heap()->IterateStrongRoots(visitor, VISIT_ONLY_STRONG);
+
+ // Handle the string table specially.
+ MarkStringTable(visitor);
+
+ MarkWeakObjectToCodeTable();
+
+ // There may be overflowed objects in the heap. Visit them now.
+ while (marking_deque_.overflowed()) {
+ RefillMarkingDeque();
+ EmptyMarkingDeque();
+ }
+}
+
+
+void MarkCompactCollector::MarkImplicitRefGroups() {
+ List<ImplicitRefGroup*>* ref_groups =
+ isolate()->global_handles()->implicit_ref_groups();
+
+ int last = 0;
+ for (int i = 0; i < ref_groups->length(); i++) {
+ ImplicitRefGroup* entry = ref_groups->at(i);
+ DCHECK(entry != NULL);
+
+ if (!IsMarked(*entry->parent)) {
+ (*ref_groups)[last++] = entry;
+ continue;
+ }
+
+ Object*** children = entry->children;
+ // A parent object is marked, so mark all child heap objects.
+ for (size_t j = 0; j < entry->length; ++j) {
+ if ((*children[j])->IsHeapObject()) {
+ HeapObject* child = HeapObject::cast(*children[j]);
+ MarkBit mark = Marking::MarkBitFrom(child);
+ MarkObject(child, mark);
+ }
+ }
+
+ // Once the entire group has been marked, dispose it because it's
+ // not needed anymore.
+ delete entry;
+ }
+ ref_groups->Rewind(last);
+}
+
+
+void MarkCompactCollector::MarkWeakObjectToCodeTable() {
+ HeapObject* weak_object_to_code_table =
+ HeapObject::cast(heap()->weak_object_to_code_table());
+ if (!IsMarked(weak_object_to_code_table)) {
+ MarkBit mark = Marking::MarkBitFrom(weak_object_to_code_table);
+ SetMark(weak_object_to_code_table, mark);
+ }
+}
+
+
+// Mark all objects reachable from the objects on the marking stack.
+// Before: the marking stack contains zero or more heap object pointers.
+// After: the marking stack is empty, and all objects reachable from the
+// marking stack have been marked, or are overflowed in the heap.
+void MarkCompactCollector::EmptyMarkingDeque() {
+ while (!marking_deque_.IsEmpty()) {
+ HeapObject* object = marking_deque_.Pop();
+ DCHECK(object->IsHeapObject());
+ DCHECK(heap()->Contains(object));
+ DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object)));
+
+ Map* map = object->map();
+ MarkBit map_mark = Marking::MarkBitFrom(map);
+ MarkObject(map, map_mark);
+
+ MarkCompactMarkingVisitor::IterateBody(map, object);
+ }
+}
+
+
+// Sweep the heap for overflowed objects, clear their overflow bits, and
+// push them on the marking stack. Stop early if the marking stack fills
+// before sweeping completes. If sweeping completes, there are no remaining
+// overflowed objects in the heap so the overflow flag on the markings stack
+// is cleared.
+void MarkCompactCollector::RefillMarkingDeque() {
+ DCHECK(marking_deque_.overflowed());
+
+ DiscoverGreyObjectsInNewSpace(heap(), &marking_deque_);
+ if (marking_deque_.IsFull()) return;
+
+ DiscoverGreyObjectsInSpace(heap(), &marking_deque_,
+ heap()->old_pointer_space());
+ if (marking_deque_.IsFull()) return;
+
+ DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->old_data_space());
+ if (marking_deque_.IsFull()) return;
+
+ DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->code_space());
+ if (marking_deque_.IsFull()) return;
+
+ DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->map_space());
+ if (marking_deque_.IsFull()) return;
+
+ DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->cell_space());
+ if (marking_deque_.IsFull()) return;
+
+ DiscoverGreyObjectsInSpace(heap(), &marking_deque_,
+ heap()->property_cell_space());
+ if (marking_deque_.IsFull()) return;
+
+ LargeObjectIterator lo_it(heap()->lo_space());
+ DiscoverGreyObjectsWithIterator(heap(), &marking_deque_, &lo_it);
+ if (marking_deque_.IsFull()) return;
+
+ marking_deque_.ClearOverflowed();
+}
+
+
+// Mark all objects reachable (transitively) from objects on the marking
+// stack. Before: the marking stack contains zero or more heap object
+// pointers. After: the marking stack is empty and there are no overflowed
+// objects in the heap.
+void MarkCompactCollector::ProcessMarkingDeque() {
+ EmptyMarkingDeque();
+ while (marking_deque_.overflowed()) {
+ RefillMarkingDeque();
+ EmptyMarkingDeque();
+ }
+}
+
+
+// Mark all objects reachable (transitively) from objects on the marking
+// stack including references only considered in the atomic marking pause.
+void MarkCompactCollector::ProcessEphemeralMarking(ObjectVisitor* visitor) {
+ bool work_to_do = true;
+ DCHECK(marking_deque_.IsEmpty());
+ while (work_to_do) {
+ isolate()->global_handles()->IterateObjectGroups(
+ visitor, &IsUnmarkedHeapObjectWithHeap);
+ MarkImplicitRefGroups();
+ ProcessWeakCollections();
+ work_to_do = !marking_deque_.IsEmpty();
+ ProcessMarkingDeque();
+ }
+}
+
+
+void MarkCompactCollector::ProcessTopOptimizedFrame(ObjectVisitor* visitor) {
+ for (StackFrameIterator it(isolate(), isolate()->thread_local_top());
+ !it.done(); it.Advance()) {
+ if (it.frame()->type() == StackFrame::JAVA_SCRIPT) {
+ return;
+ }
+ if (it.frame()->type() == StackFrame::OPTIMIZED) {
+ Code* code = it.frame()->LookupCode();
+ if (!code->CanDeoptAt(it.frame()->pc())) {
+ code->CodeIterateBody(visitor);
+ }
+ ProcessMarkingDeque();
+ return;
+ }
+ }
+}
+
+
+void MarkCompactCollector::MarkLiveObjects() {
+ GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_MARK);
+ double start_time = 0.0;
+ if (FLAG_print_cumulative_gc_stat) {
+ start_time = base::OS::TimeCurrentMillis();
+ }
+ // The recursive GC marker detects when it is nearing stack overflow,
+ // and switches to a different marking system. JS interrupts interfere
+ // with the C stack limit check.
+ PostponeInterruptsScope postpone(isolate());
+
+ bool incremental_marking_overflowed = false;
+ IncrementalMarking* incremental_marking = heap_->incremental_marking();
+ if (was_marked_incrementally_) {
+ // Finalize the incremental marking and check whether we had an overflow.
+ // Both markers use grey color to mark overflowed objects so
+ // non-incremental marker can deal with them as if overflow
+ // occured during normal marking.
+ // But incremental marker uses a separate marking deque
+ // so we have to explicitly copy its overflow state.
+ incremental_marking->Finalize();
+ incremental_marking_overflowed =
+ incremental_marking->marking_deque()->overflowed();
+ incremental_marking->marking_deque()->ClearOverflowed();
+ } else {
+ // Abort any pending incremental activities e.g. incremental sweeping.
+ incremental_marking->Abort();
+ }
+
+#ifdef DEBUG
+ DCHECK(state_ == PREPARE_GC);
+ state_ = MARK_LIVE_OBJECTS;
+#endif
+ // The to space contains live objects, a page in from space is used as a
+ // marking stack.
+ Address marking_deque_start = heap()->new_space()->FromSpacePageLow();
+ Address marking_deque_end = heap()->new_space()->FromSpacePageHigh();
+ if (FLAG_force_marking_deque_overflows) {
+ marking_deque_end = marking_deque_start + 64 * kPointerSize;
+ }
+ marking_deque_.Initialize(marking_deque_start, marking_deque_end);
+ DCHECK(!marking_deque_.overflowed());
+
+ if (incremental_marking_overflowed) {
+ // There are overflowed objects left in the heap after incremental marking.
+ marking_deque_.SetOverflowed();
+ }
+
+ PrepareForCodeFlushing();
+
+ if (was_marked_incrementally_) {
+ // There is no write barrier on cells so we have to scan them now at the end
+ // of the incremental marking.
+ {
+ HeapObjectIterator cell_iterator(heap()->cell_space());
+ HeapObject* cell;
+ while ((cell = cell_iterator.Next()) != NULL) {
+ DCHECK(cell->IsCell());
+ if (IsMarked(cell)) {
+ int offset = Cell::kValueOffset;
+ MarkCompactMarkingVisitor::VisitPointer(
+ heap(), reinterpret_cast<Object**>(cell->address() + offset));
+ }
+ }
+ }
+ {
+ HeapObjectIterator js_global_property_cell_iterator(
+ heap()->property_cell_space());
+ HeapObject* cell;
+ while ((cell = js_global_property_cell_iterator.Next()) != NULL) {
+ DCHECK(cell->IsPropertyCell());
+ if (IsMarked(cell)) {
+ MarkCompactMarkingVisitor::VisitPropertyCell(cell->map(), cell);
+ }
+ }
+ }
+ }
+
+ RootMarkingVisitor root_visitor(heap());
+ MarkRoots(&root_visitor);
+
+ ProcessTopOptimizedFrame(&root_visitor);
+
+ // The objects reachable from the roots are marked, yet unreachable
+ // objects are unmarked. Mark objects reachable due to host
+ // application specific logic or through Harmony weak maps.
+ ProcessEphemeralMarking(&root_visitor);
+
+ // The objects reachable from the roots, weak maps or object groups
+ // are marked, yet unreachable objects are unmarked. Mark objects
+ // reachable only from weak global handles.
+ //
+ // First we identify nonlive weak handles and mark them as pending
+ // destruction.
+ heap()->isolate()->global_handles()->IdentifyWeakHandles(
+ &IsUnmarkedHeapObject);
+ // Then we mark the objects and process the transitive closure.
+ heap()->isolate()->global_handles()->IterateWeakRoots(&root_visitor);
+ while (marking_deque_.overflowed()) {
+ RefillMarkingDeque();
+ EmptyMarkingDeque();
+ }
+
+ // Repeat host application specific and Harmony weak maps marking to
+ // mark unmarked objects reachable from the weak roots.
+ ProcessEphemeralMarking(&root_visitor);
+
+ AfterMarking();
+
+ if (FLAG_print_cumulative_gc_stat) {
+ heap_->tracer()->AddMarkingTime(base::OS::TimeCurrentMillis() - start_time);
+ }
+}
+
+
+void MarkCompactCollector::AfterMarking() {
+ // Object literal map caches reference strings (cache keys) and maps
+ // (cache values). At this point still useful maps have already been
+ // marked. Mark the keys for the alive values before we process the
+ // string table.
+ ProcessMapCaches();
+
+ // Prune the string table removing all strings only pointed to by the
+ // string table. Cannot use string_table() here because the string
+ // table is marked.
+ StringTable* string_table = heap()->string_table();
+ InternalizedStringTableCleaner internalized_visitor(heap());
+ string_table->IterateElements(&internalized_visitor);
+ string_table->ElementsRemoved(internalized_visitor.PointersRemoved());
+
+ ExternalStringTableCleaner external_visitor(heap());
+ heap()->external_string_table_.Iterate(&external_visitor);
+ heap()->external_string_table_.CleanUp();
+
+ // Process the weak references.
+ MarkCompactWeakObjectRetainer mark_compact_object_retainer;
+ heap()->ProcessWeakReferences(&mark_compact_object_retainer);
+
+ // Remove object groups after marking phase.
+ heap()->isolate()->global_handles()->RemoveObjectGroups();
+ heap()->isolate()->global_handles()->RemoveImplicitRefGroups();
+
+ // Flush code from collected candidates.
+ if (is_code_flushing_enabled()) {
+ code_flusher_->ProcessCandidates();
+ // If incremental marker does not support code flushing, we need to
+ // disable it before incremental marking steps for next cycle.
+ if (FLAG_flush_code && !FLAG_flush_code_incrementally) {
+ EnableCodeFlushing(false);
+ }
+ }
+
+ if (FLAG_track_gc_object_stats) {
+ heap()->CheckpointObjectStats();
+ }
+}
+
+
+void MarkCompactCollector::ProcessMapCaches() {
+ Object* raw_context = heap()->native_contexts_list();
+ while (raw_context != heap()->undefined_value()) {
+ Context* context = reinterpret_cast<Context*>(raw_context);
+ if (IsMarked(context)) {
+ HeapObject* raw_map_cache =
+ HeapObject::cast(context->get(Context::MAP_CACHE_INDEX));
+ // A map cache may be reachable from the stack. In this case
+ // it's already transitively marked and it's too late to clean
+ // up its parts.
+ if (!IsMarked(raw_map_cache) &&
+ raw_map_cache != heap()->undefined_value()) {
+ MapCache* map_cache = reinterpret_cast<MapCache*>(raw_map_cache);
+ int existing_elements = map_cache->NumberOfElements();
+ int used_elements = 0;
+ for (int i = MapCache::kElementsStartIndex; i < map_cache->length();
+ i += MapCache::kEntrySize) {
+ Object* raw_key = map_cache->get(i);
+ if (raw_key == heap()->undefined_value() ||
+ raw_key == heap()->the_hole_value())
+ continue;
+ STATIC_ASSERT(MapCache::kEntrySize == 2);
+ Object* raw_map = map_cache->get(i + 1);
+ if (raw_map->IsHeapObject() && IsMarked(raw_map)) {
+ ++used_elements;
+ } else {
+ // Delete useless entries with unmarked maps.
+ DCHECK(raw_map->IsMap());
+ map_cache->set_the_hole(i);
+ map_cache->set_the_hole(i + 1);
+ }
+ }
+ if (used_elements == 0) {
+ context->set(Context::MAP_CACHE_INDEX, heap()->undefined_value());
+ } else {
+ // Note: we don't actually shrink the cache here to avoid
+ // extra complexity during GC. We rely on subsequent cache
+ // usages (EnsureCapacity) to do this.
+ map_cache->ElementsRemoved(existing_elements - used_elements);
+ MarkBit map_cache_markbit = Marking::MarkBitFrom(map_cache);
+ MarkObject(map_cache, map_cache_markbit);
+ }
+ }
+ }
+ // Move to next element in the list.
+ raw_context = context->get(Context::NEXT_CONTEXT_LINK);
+ }
+ ProcessMarkingDeque();
+}
+
+
+void MarkCompactCollector::ClearNonLiveReferences() {
+ // Iterate over the map space, setting map transitions that go from
+ // a marked map to an unmarked map to null transitions. This action
+ // is carried out only on maps of JSObjects and related subtypes.
+ HeapObjectIterator map_iterator(heap()->map_space());
+ for (HeapObject* obj = map_iterator.Next(); obj != NULL;
+ obj = map_iterator.Next()) {
+ Map* map = Map::cast(obj);
+
+ if (!map->CanTransition()) continue;
+
+ MarkBit map_mark = Marking::MarkBitFrom(map);
+ ClearNonLivePrototypeTransitions(map);
+ ClearNonLiveMapTransitions(map, map_mark);
+
+ if (map_mark.Get()) {
+ ClearNonLiveDependentCode(map->dependent_code());
+ } else {
+ ClearDependentCode(map->dependent_code());
+ map->set_dependent_code(DependentCode::cast(heap()->empty_fixed_array()));
+ }
+ }
+
+ // Iterate over property cell space, removing dependent code that is not
+ // otherwise kept alive by strong references.
+ HeapObjectIterator cell_iterator(heap_->property_cell_space());
+ for (HeapObject* cell = cell_iterator.Next(); cell != NULL;
+ cell = cell_iterator.Next()) {
+ if (IsMarked(cell)) {
+ ClearNonLiveDependentCode(PropertyCell::cast(cell)->dependent_code());
+ }
+ }
+
+ // Iterate over allocation sites, removing dependent code that is not
+ // otherwise kept alive by strong references.
+ Object* undefined = heap()->undefined_value();
+ for (Object* site = heap()->allocation_sites_list(); site != undefined;
+ site = AllocationSite::cast(site)->weak_next()) {
+ if (IsMarked(site)) {
+ ClearNonLiveDependentCode(AllocationSite::cast(site)->dependent_code());
+ }
+ }
+
+ if (heap_->weak_object_to_code_table()->IsHashTable()) {
+ WeakHashTable* table =
+ WeakHashTable::cast(heap_->weak_object_to_code_table());
+ uint32_t capacity = table->Capacity();
+ for (uint32_t i = 0; i < capacity; i++) {
+ uint32_t key_index = table->EntryToIndex(i);
+ Object* key = table->get(key_index);
+ if (!table->IsKey(key)) continue;
+ uint32_t value_index = table->EntryToValueIndex(i);
+ Object* value = table->get(value_index);
+ if (key->IsCell() && !IsMarked(key)) {
+ Cell* cell = Cell::cast(key);
+ Object* object = cell->value();
+ if (IsMarked(object)) {
+ MarkBit mark = Marking::MarkBitFrom(cell);
+ SetMark(cell, mark);
+ Object** value_slot = HeapObject::RawField(cell, Cell::kValueOffset);
+ RecordSlot(value_slot, value_slot, *value_slot);
+ }
+ }
+ if (IsMarked(key)) {
+ if (!IsMarked(value)) {
+ HeapObject* obj = HeapObject::cast(value);
+ MarkBit mark = Marking::MarkBitFrom(obj);
+ SetMark(obj, mark);
+ }
+ ClearNonLiveDependentCode(DependentCode::cast(value));
+ } else {
+ ClearDependentCode(DependentCode::cast(value));
+ table->set(key_index, heap_->the_hole_value());
+ table->set(value_index, heap_->the_hole_value());
+ table->ElementRemoved();
+ }
+ }
+ }
+}
+
+
+void MarkCompactCollector::ClearNonLivePrototypeTransitions(Map* map) {
+ int number_of_transitions = map->NumberOfProtoTransitions();
+ FixedArray* prototype_transitions = map->GetPrototypeTransitions();
+
+ int new_number_of_transitions = 0;
+ const int header = Map::kProtoTransitionHeaderSize;
+ const int proto_offset = header + Map::kProtoTransitionPrototypeOffset;
+ const int map_offset = header + Map::kProtoTransitionMapOffset;
+ const int step = Map::kProtoTransitionElementsPerEntry;
+ for (int i = 0; i < number_of_transitions; i++) {
+ Object* prototype = prototype_transitions->get(proto_offset + i * step);
+ Object* cached_map = prototype_transitions->get(map_offset + i * step);
+ if (IsMarked(prototype) && IsMarked(cached_map)) {
+ DCHECK(!prototype->IsUndefined());
+ int proto_index = proto_offset + new_number_of_transitions * step;
+ int map_index = map_offset + new_number_of_transitions * step;
+ if (new_number_of_transitions != i) {
+ prototype_transitions->set(proto_index, prototype,
+ UPDATE_WRITE_BARRIER);
+ prototype_transitions->set(map_index, cached_map, SKIP_WRITE_BARRIER);
+ }
+ Object** slot = prototype_transitions->RawFieldOfElementAt(proto_index);
+ RecordSlot(slot, slot, prototype);
+ new_number_of_transitions++;
+ }
+ }
+
+ if (new_number_of_transitions != number_of_transitions) {
+ map->SetNumberOfProtoTransitions(new_number_of_transitions);
+ }
+
+ // Fill slots that became free with undefined value.
+ for (int i = new_number_of_transitions * step;
+ i < number_of_transitions * step; i++) {
+ prototype_transitions->set_undefined(header + i);
+ }
+}
+
+
+void MarkCompactCollector::ClearNonLiveMapTransitions(Map* map,
+ MarkBit map_mark) {
+ Object* potential_parent = map->GetBackPointer();
+ if (!potential_parent->IsMap()) return;
+ Map* parent = Map::cast(potential_parent);
+
+ // Follow back pointer, check whether we are dealing with a map transition
+ // from a live map to a dead path and in case clear transitions of parent.
+ bool current_is_alive = map_mark.Get();
+ bool parent_is_alive = Marking::MarkBitFrom(parent).Get();
+ if (!current_is_alive && parent_is_alive) {
+ ClearMapTransitions(parent);
+ }
+}
+
+
+// Clear a possible back pointer in case the transition leads to a dead map.
+// Return true in case a back pointer has been cleared and false otherwise.
+bool MarkCompactCollector::ClearMapBackPointer(Map* target) {
+ if (Marking::MarkBitFrom(target).Get()) return false;
+ target->SetBackPointer(heap_->undefined_value(), SKIP_WRITE_BARRIER);
+ return true;
+}
+
+
+void MarkCompactCollector::ClearMapTransitions(Map* map) {
+ // If there are no transitions to be cleared, return.
+ // TODO(verwaest) Should be an assert, otherwise back pointers are not
+ // properly cleared.
+ if (!map->HasTransitionArray()) return;
+
+ TransitionArray* t = map->transitions();
+
+ int transition_index = 0;
+
+ DescriptorArray* descriptors = map->instance_descriptors();
+ bool descriptors_owner_died = false;
+
+ // Compact all live descriptors to the left.
+ for (int i = 0; i < t->number_of_transitions(); ++i) {
+ Map* target = t->GetTarget(i);
+ if (ClearMapBackPointer(target)) {
+ if (target->instance_descriptors() == descriptors) {
+ descriptors_owner_died = true;
+ }
+ } else {
+ if (i != transition_index) {
+ Name* key = t->GetKey(i);
+ t->SetKey(transition_index, key);
+ Object** key_slot = t->GetKeySlot(transition_index);
+ RecordSlot(key_slot, key_slot, key);
+ // Target slots do not need to be recorded since maps are not compacted.
+ t->SetTarget(transition_index, t->GetTarget(i));
+ }
+ transition_index++;
+ }
+ }
+
+ // If there are no transitions to be cleared, return.
+ // TODO(verwaest) Should be an assert, otherwise back pointers are not
+ // properly cleared.
+ if (transition_index == t->number_of_transitions()) return;
+
+ int number_of_own_descriptors = map->NumberOfOwnDescriptors();
+
+ if (descriptors_owner_died) {
+ if (number_of_own_descriptors > 0) {
+ TrimDescriptorArray(map, descriptors, number_of_own_descriptors);
+ DCHECK(descriptors->number_of_descriptors() == number_of_own_descriptors);
+ map->set_owns_descriptors(true);
+ } else {
+ DCHECK(descriptors == heap_->empty_descriptor_array());
+ }
+ }
+
+ // Note that we never eliminate a transition array, though we might right-trim
+ // such that number_of_transitions() == 0. If this assumption changes,
+ // TransitionArray::CopyInsert() will need to deal with the case that a
+ // transition array disappeared during GC.
+ int trim = t->number_of_transitions() - transition_index;
+ if (trim > 0) {
+ heap_->RightTrimFixedArray<Heap::FROM_GC>(
+ t, t->IsSimpleTransition() ? trim
+ : trim * TransitionArray::kTransitionSize);
+ }
+ DCHECK(map->HasTransitionArray());
+}
+
+
+void MarkCompactCollector::TrimDescriptorArray(Map* map,
+ DescriptorArray* descriptors,
+ int number_of_own_descriptors) {
+ int number_of_descriptors = descriptors->number_of_descriptors_storage();
+ int to_trim = number_of_descriptors - number_of_own_descriptors;
+ if (to_trim == 0) return;
+
+ heap_->RightTrimFixedArray<Heap::FROM_GC>(
+ descriptors, to_trim * DescriptorArray::kDescriptorSize);
+ descriptors->SetNumberOfDescriptors(number_of_own_descriptors);
+
+ if (descriptors->HasEnumCache()) TrimEnumCache(map, descriptors);
+ descriptors->Sort();
+}
+
+
+void MarkCompactCollector::TrimEnumCache(Map* map,
+ DescriptorArray* descriptors) {
+ int live_enum = map->EnumLength();
+ if (live_enum == kInvalidEnumCacheSentinel) {
+ live_enum = map->NumberOfDescribedProperties(OWN_DESCRIPTORS, DONT_ENUM);
+ }
+ if (live_enum == 0) return descriptors->ClearEnumCache();
+
+ FixedArray* enum_cache = descriptors->GetEnumCache();
+
+ int to_trim = enum_cache->length() - live_enum;
+ if (to_trim <= 0) return;
+ heap_->RightTrimFixedArray<Heap::FROM_GC>(descriptors->GetEnumCache(),
+ to_trim);
+
+ if (!descriptors->HasEnumIndicesCache()) return;
+ FixedArray* enum_indices_cache = descriptors->GetEnumIndicesCache();
+ heap_->RightTrimFixedArray<Heap::FROM_GC>(enum_indices_cache, to_trim);
+}
+
+
+void MarkCompactCollector::ClearDependentICList(Object* head) {
+ Object* current = head;
+ Object* undefined = heap()->undefined_value();
+ while (current != undefined) {
+ Code* code = Code::cast(current);
+ if (IsMarked(code)) {
+ DCHECK(code->is_weak_stub());
+ IC::InvalidateMaps(code);
+ }
+ current = code->next_code_link();
+ code->set_next_code_link(undefined);
+ }
+}
+
+
+void MarkCompactCollector::ClearDependentCode(DependentCode* entries) {
+ DisallowHeapAllocation no_allocation;
+ DependentCode::GroupStartIndexes starts(entries);
+ int number_of_entries = starts.number_of_entries();
+ if (number_of_entries == 0) return;
+ int g = DependentCode::kWeakICGroup;
+ if (starts.at(g) != starts.at(g + 1)) {
+ int i = starts.at(g);
+ DCHECK(i + 1 == starts.at(g + 1));
+ Object* head = entries->object_at(i);
+ ClearDependentICList(head);
+ }
+ g = DependentCode::kWeakCodeGroup;
+ for (int i = starts.at(g); i < starts.at(g + 1); i++) {
+ // If the entry is compilation info then the map must be alive,
+ // and ClearDependentCode shouldn't be called.
+ DCHECK(entries->is_code_at(i));
+ Code* code = entries->code_at(i);
+ if (IsMarked(code) && !code->marked_for_deoptimization()) {
+ DependentCode::SetMarkedForDeoptimization(
+ code, static_cast<DependentCode::DependencyGroup>(g));
+ code->InvalidateEmbeddedObjects();
+ have_code_to_deoptimize_ = true;
+ }
+ }
+ for (int i = 0; i < number_of_entries; i++) {
+ entries->clear_at(i);
+ }
+}
+
+
+int MarkCompactCollector::ClearNonLiveDependentCodeInGroup(
+ DependentCode* entries, int group, int start, int end, int new_start) {
+ int survived = 0;
+ if (group == DependentCode::kWeakICGroup) {
+ // Dependent weak IC stubs form a linked list and only the head is stored
+ // in the dependent code array.
+ if (start != end) {
+ DCHECK(start + 1 == end);
+ Object* old_head = entries->object_at(start);
+ MarkCompactWeakObjectRetainer retainer;
+ Object* head = VisitWeakList<Code>(heap(), old_head, &retainer);
+ entries->set_object_at(new_start, head);
+ Object** slot = entries->slot_at(new_start);
+ RecordSlot(slot, slot, head);
+ // We do not compact this group even if the head is undefined,
+ // more dependent ICs are likely to be added later.
+ survived = 1;
+ }
+ } else {
+ for (int i = start; i < end; i++) {
+ Object* obj = entries->object_at(i);
+ DCHECK(obj->IsCode() || IsMarked(obj));
+ if (IsMarked(obj) &&
+ (!obj->IsCode() || !WillBeDeoptimized(Code::cast(obj)))) {
+ if (new_start + survived != i) {
+ entries->set_object_at(new_start + survived, obj);
+ }
+ Object** slot = entries->slot_at(new_start + survived);
+ RecordSlot(slot, slot, obj);
+ survived++;
+ }
+ }
+ }
+ entries->set_number_of_entries(
+ static_cast<DependentCode::DependencyGroup>(group), survived);
+ return survived;
+}
+
+
+void MarkCompactCollector::ClearNonLiveDependentCode(DependentCode* entries) {
+ DisallowHeapAllocation no_allocation;
+ DependentCode::GroupStartIndexes starts(entries);
+ int number_of_entries = starts.number_of_entries();
+ if (number_of_entries == 0) return;
+ int new_number_of_entries = 0;
+ // Go through all groups, remove dead codes and compact.
+ for (int g = 0; g < DependentCode::kGroupCount; g++) {
+ int survived = ClearNonLiveDependentCodeInGroup(
+ entries, g, starts.at(g), starts.at(g + 1), new_number_of_entries);
+ new_number_of_entries += survived;
+ }
+ for (int i = new_number_of_entries; i < number_of_entries; i++) {
+ entries->clear_at(i);
+ }
+}
+
+
+void MarkCompactCollector::ProcessWeakCollections() {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_WEAKCOLLECTION_PROCESS);
+ Object* weak_collection_obj = heap()->encountered_weak_collections();
+ while (weak_collection_obj != Smi::FromInt(0)) {
+ JSWeakCollection* weak_collection =
+ reinterpret_cast<JSWeakCollection*>(weak_collection_obj);
+ DCHECK(MarkCompactCollector::IsMarked(weak_collection));
+ if (weak_collection->table()->IsHashTable()) {
+ ObjectHashTable* table = ObjectHashTable::cast(weak_collection->table());
+ Object** anchor = reinterpret_cast<Object**>(table->address());
+ for (int i = 0; i < table->Capacity(); i++) {
+ if (MarkCompactCollector::IsMarked(HeapObject::cast(table->KeyAt(i)))) {
+ Object** key_slot =
+ table->RawFieldOfElementAt(ObjectHashTable::EntryToIndex(i));
+ RecordSlot(anchor, key_slot, *key_slot);
+ Object** value_slot =
+ table->RawFieldOfElementAt(ObjectHashTable::EntryToValueIndex(i));
+ MarkCompactMarkingVisitor::MarkObjectByPointer(this, anchor,
+ value_slot);
+ }
+ }
+ }
+ weak_collection_obj = weak_collection->next();
+ }
+}
+
+
+void MarkCompactCollector::ClearWeakCollections() {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_WEAKCOLLECTION_CLEAR);
+ Object* weak_collection_obj = heap()->encountered_weak_collections();
+ while (weak_collection_obj != Smi::FromInt(0)) {
+ JSWeakCollection* weak_collection =
+ reinterpret_cast<JSWeakCollection*>(weak_collection_obj);
+ DCHECK(MarkCompactCollector::IsMarked(weak_collection));
+ if (weak_collection->table()->IsHashTable()) {
+ ObjectHashTable* table = ObjectHashTable::cast(weak_collection->table());
+ for (int i = 0; i < table->Capacity(); i++) {
+ HeapObject* key = HeapObject::cast(table->KeyAt(i));
+ if (!MarkCompactCollector::IsMarked(key)) {
+ table->RemoveEntry(i);
+ }
+ }
+ }
+ weak_collection_obj = weak_collection->next();
+ weak_collection->set_next(heap()->undefined_value());
+ }
+ heap()->set_encountered_weak_collections(Smi::FromInt(0));
+}
+
+
+void MarkCompactCollector::AbortWeakCollections() {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_WEAKCOLLECTION_ABORT);
+ Object* weak_collection_obj = heap()->encountered_weak_collections();
+ while (weak_collection_obj != Smi::FromInt(0)) {
+ JSWeakCollection* weak_collection =
+ reinterpret_cast<JSWeakCollection*>(weak_collection_obj);
+ weak_collection_obj = weak_collection->next();
+ weak_collection->set_next(heap()->undefined_value());
+ }
+ heap()->set_encountered_weak_collections(Smi::FromInt(0));
+}
+
+
+void MarkCompactCollector::RecordMigratedSlot(Object* value, Address slot) {
+ if (heap_->InNewSpace(value)) {
+ heap_->store_buffer()->Mark(slot);
+ } else if (value->IsHeapObject() && IsOnEvacuationCandidate(value)) {
+ SlotsBuffer::AddTo(&slots_buffer_allocator_, &migration_slots_buffer_,
+ reinterpret_cast<Object**>(slot),
+ SlotsBuffer::IGNORE_OVERFLOW);
+ }
+}
+
+
+// We scavange new space simultaneously with sweeping. This is done in two
+// passes.
+//
+// The first pass migrates all alive objects from one semispace to another or
+// promotes them to old space. Forwarding address is written directly into
+// first word of object without any encoding. If object is dead we write
+// NULL as a forwarding address.
+//
+// The second pass updates pointers to new space in all spaces. It is possible
+// to encounter pointers to dead new space objects during traversal of pointers
+// to new space. We should clear them to avoid encountering them during next
+// pointer iteration. This is an issue if the store buffer overflows and we
+// have to scan the entire old space, including dead objects, looking for
+// pointers to new space.
+void MarkCompactCollector::MigrateObject(HeapObject* dst, HeapObject* src,
+ int size, AllocationSpace dest) {
+ Address dst_addr = dst->address();
+ Address src_addr = src->address();
+ DCHECK(heap()->AllowedToBeMigrated(src, dest));
+ DCHECK(dest != LO_SPACE && size <= Page::kMaxRegularHeapObjectSize);
+ if (dest == OLD_POINTER_SPACE) {
+ Address src_slot = src_addr;
+ Address dst_slot = dst_addr;
+ DCHECK(IsAligned(size, kPointerSize));
+
+ for (int remaining = size / kPointerSize; remaining > 0; remaining--) {
+ Object* value = Memory::Object_at(src_slot);
+
+ Memory::Object_at(dst_slot) = value;
+
+ if (!src->MayContainRawValues()) {
+ RecordMigratedSlot(value, dst_slot);
+ }
+
+ src_slot += kPointerSize;
+ dst_slot += kPointerSize;
+ }
+
+ if (compacting_ && dst->IsJSFunction()) {
+ Address code_entry_slot = dst_addr + JSFunction::kCodeEntryOffset;
+ Address code_entry = Memory::Address_at(code_entry_slot);
+
+ if (Page::FromAddress(code_entry)->IsEvacuationCandidate()) {
+ SlotsBuffer::AddTo(&slots_buffer_allocator_, &migration_slots_buffer_,
+ SlotsBuffer::CODE_ENTRY_SLOT, code_entry_slot,
+ SlotsBuffer::IGNORE_OVERFLOW);
+ }
+ } else if (dst->IsConstantPoolArray()) {
+ // We special case ConstantPoolArrays since they could contain integers
+ // value entries which look like tagged pointers.
+ // TODO(mstarzinger): restructure this code to avoid this special-casing.
+ ConstantPoolArray* array = ConstantPoolArray::cast(dst);
+ ConstantPoolArray::Iterator code_iter(array, ConstantPoolArray::CODE_PTR);
+ while (!code_iter.is_finished()) {
+ Address code_entry_slot =
+ dst_addr + array->OffsetOfElementAt(code_iter.next_index());
+ Address code_entry = Memory::Address_at(code_entry_slot);
+
+ if (Page::FromAddress(code_entry)->IsEvacuationCandidate()) {
+ SlotsBuffer::AddTo(&slots_buffer_allocator_, &migration_slots_buffer_,
+ SlotsBuffer::CODE_ENTRY_SLOT, code_entry_slot,
+ SlotsBuffer::IGNORE_OVERFLOW);
+ }
+ }
+ ConstantPoolArray::Iterator heap_iter(array, ConstantPoolArray::HEAP_PTR);
+ while (!heap_iter.is_finished()) {
+ Address heap_slot =
+ dst_addr + array->OffsetOfElementAt(heap_iter.next_index());
+ Object* value = Memory::Object_at(heap_slot);
+ RecordMigratedSlot(value, heap_slot);
+ }
+ }
+ } else if (dest == CODE_SPACE) {
+ PROFILE(isolate(), CodeMoveEvent(src_addr, dst_addr));
+ heap()->MoveBlock(dst_addr, src_addr, size);
+ SlotsBuffer::AddTo(&slots_buffer_allocator_, &migration_slots_buffer_,
+ SlotsBuffer::RELOCATED_CODE_OBJECT, dst_addr,
+ SlotsBuffer::IGNORE_OVERFLOW);
+ Code::cast(dst)->Relocate(dst_addr - src_addr);
+ } else {
+ DCHECK(dest == OLD_DATA_SPACE || dest == NEW_SPACE);
+ heap()->MoveBlock(dst_addr, src_addr, size);
+ }
+ heap()->OnMoveEvent(dst, src, size);
+ Memory::Address_at(src_addr) = dst_addr;
+}
+
+
+// Visitor for updating pointers from live objects in old spaces to new space.
+// It does not expect to encounter pointers to dead objects.
+class PointersUpdatingVisitor : public ObjectVisitor {
+ public:
+ explicit PointersUpdatingVisitor(Heap* heap) : heap_(heap) {}
+
+ void VisitPointer(Object** p) { UpdatePointer(p); }
+
+ void VisitPointers(Object** start, Object** end) {
+ for (Object** p = start; p < end; p++) UpdatePointer(p);
+ }
+
+ void VisitEmbeddedPointer(RelocInfo* rinfo) {
+ DCHECK(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT);
+ Object* target = rinfo->target_object();
+ Object* old_target = target;
+ VisitPointer(&target);
+ // Avoid unnecessary changes that might unnecessary flush the instruction
+ // cache.
+ if (target != old_target) {
+ rinfo->set_target_object(target);
+ }
+ }
+
+ void VisitCodeTarget(RelocInfo* rinfo) {
+ DCHECK(RelocInfo::IsCodeTarget(rinfo->rmode()));
+ Object* target = Code::GetCodeFromTargetAddress(rinfo->target_address());
+ Object* old_target = target;
+ VisitPointer(&target);
+ if (target != old_target) {
+ rinfo->set_target_address(Code::cast(target)->instruction_start());
+ }
+ }
+
+ void VisitCodeAgeSequence(RelocInfo* rinfo) {
+ DCHECK(RelocInfo::IsCodeAgeSequence(rinfo->rmode()));
+ Object* stub = rinfo->code_age_stub();
+ DCHECK(stub != NULL);
+ VisitPointer(&stub);
+ if (stub != rinfo->code_age_stub()) {
+ rinfo->set_code_age_stub(Code::cast(stub));
+ }
+ }
+
+ void VisitDebugTarget(RelocInfo* rinfo) {
+ DCHECK((RelocInfo::IsJSReturn(rinfo->rmode()) &&
+ rinfo->IsPatchedReturnSequence()) ||
+ (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) &&
+ rinfo->IsPatchedDebugBreakSlotSequence()));
+ Object* target = Code::GetCodeFromTargetAddress(rinfo->call_address());
+ VisitPointer(&target);
+ rinfo->set_call_address(Code::cast(target)->instruction_start());
+ }
+
+ static inline void UpdateSlot(Heap* heap, Object** slot) {
+ Object* obj = *slot;
+
+ if (!obj->IsHeapObject()) return;
+
+ HeapObject* heap_obj = HeapObject::cast(obj);
+
+ MapWord map_word = heap_obj->map_word();
+ if (map_word.IsForwardingAddress()) {
+ DCHECK(heap->InFromSpace(heap_obj) ||
+ MarkCompactCollector::IsOnEvacuationCandidate(heap_obj));
+ HeapObject* target = map_word.ToForwardingAddress();
+ *slot = target;
+ DCHECK(!heap->InFromSpace(target) &&
+ !MarkCompactCollector::IsOnEvacuationCandidate(target));
+ }
+ }
+
+ private:
+ inline void UpdatePointer(Object** p) { UpdateSlot(heap_, p); }
+
+ Heap* heap_;
+};
+
+
+static void UpdatePointer(HeapObject** address, HeapObject* object) {
+ Address new_addr = Memory::Address_at(object->address());
+
+ // The new space sweep will overwrite the map word of dead objects
+ // with NULL. In this case we do not need to transfer this entry to
+ // the store buffer which we are rebuilding.
+ // We perform the pointer update with a no barrier compare-and-swap. The
+ // compare and swap may fail in the case where the pointer update tries to
+ // update garbage memory which was concurrently accessed by the sweeper.
+ if (new_addr != NULL) {
+ base::NoBarrier_CompareAndSwap(
+ reinterpret_cast<base::AtomicWord*>(address),
+ reinterpret_cast<base::AtomicWord>(object),
+ reinterpret_cast<base::AtomicWord>(HeapObject::FromAddress(new_addr)));
+ }
+}
+
+
+static String* UpdateReferenceInExternalStringTableEntry(Heap* heap,
+ Object** p) {
+ MapWord map_word = HeapObject::cast(*p)->map_word();
+
+ if (map_word.IsForwardingAddress()) {
+ return String::cast(map_word.ToForwardingAddress());
+ }
+
+ return String::cast(*p);
+}
+
+
+bool MarkCompactCollector::TryPromoteObject(HeapObject* object,
+ int object_size) {
+ DCHECK(object_size <= Page::kMaxRegularHeapObjectSize);
+
+ OldSpace* target_space = heap()->TargetSpace(object);
+
+ DCHECK(target_space == heap()->old_pointer_space() ||
+ target_space == heap()->old_data_space());
+ HeapObject* target;
+ AllocationResult allocation = target_space->AllocateRaw(object_size);
+ if (allocation.To(&target)) {
+ MigrateObject(target, object, object_size, target_space->identity());
+ heap()->IncrementPromotedObjectsSize(object_size);
+ return true;
+ }
+
+ return false;
+}
+
+
+void MarkCompactCollector::EvacuateNewSpace() {
+ // There are soft limits in the allocation code, designed trigger a mark
+ // sweep collection by failing allocations. But since we are already in
+ // a mark-sweep allocation, there is no sense in trying to trigger one.
+ AlwaysAllocateScope scope(isolate());
+
+ NewSpace* new_space = heap()->new_space();
+
+ // Store allocation range before flipping semispaces.
+ Address from_bottom = new_space->bottom();
+ Address from_top = new_space->top();
+
+ // Flip the semispaces. After flipping, to space is empty, from space has
+ // live objects.
+ new_space->Flip();
+ new_space->ResetAllocationInfo();
+
+ int survivors_size = 0;
+
+ // First pass: traverse all objects in inactive semispace, remove marks,
+ // migrate live objects and write forwarding addresses. This stage puts
+ // new entries in the store buffer and may cause some pages to be marked
+ // scan-on-scavenge.
+ NewSpacePageIterator it(from_bottom, from_top);
+ while (it.has_next()) {
+ NewSpacePage* p = it.next();
+ survivors_size += DiscoverAndEvacuateBlackObjectsOnPage(new_space, p);
+ }
+
+ heap_->IncrementYoungSurvivorsCounter(survivors_size);
+ new_space->set_age_mark(new_space->top());
+}
+
+
+void MarkCompactCollector::EvacuateLiveObjectsFromPage(Page* p) {
+ AlwaysAllocateScope always_allocate(isolate());
+ PagedSpace* space = static_cast<PagedSpace*>(p->owner());
+ DCHECK(p->IsEvacuationCandidate() && !p->WasSwept());
+ p->SetWasSwept();
+
+ int offsets[16];
+
+ for (MarkBitCellIterator it(p); !it.Done(); it.Advance()) {
+ Address cell_base = it.CurrentCellBase();
+ MarkBit::CellType* cell = it.CurrentCell();
+
+ if (*cell == 0) continue;
+
+ int live_objects = MarkWordToObjectStarts(*cell, offsets);
+ for (int i = 0; i < live_objects; i++) {
+ Address object_addr = cell_base + offsets[i] * kPointerSize;
+ HeapObject* object = HeapObject::FromAddress(object_addr);
+ DCHECK(Marking::IsBlack(Marking::MarkBitFrom(object)));
+
+ int size = object->Size();
+
+ HeapObject* target_object;
+ AllocationResult allocation = space->AllocateRaw(size);
+ if (!allocation.To(&target_object)) {
+ // If allocation failed, use emergency memory and re-try allocation.
+ CHECK(space->HasEmergencyMemory());
+ space->UseEmergencyMemory();
+ allocation = space->AllocateRaw(size);
+ }
+ if (!allocation.To(&target_object)) {
+ // OS refused to give us memory.
+ V8::FatalProcessOutOfMemory("Evacuation");
+ return;
+ }
+
+ MigrateObject(target_object, object, size, space->identity());
+ DCHECK(object->map_word().IsForwardingAddress());
+ }
+
+ // Clear marking bits for current cell.
+ *cell = 0;
+ }
+ p->ResetLiveBytes();
+}
+
+
+void MarkCompactCollector::EvacuatePages() {
+ int npages = evacuation_candidates_.length();
+ for (int i = 0; i < npages; i++) {
+ Page* p = evacuation_candidates_[i];
+ DCHECK(p->IsEvacuationCandidate() ||
+ p->IsFlagSet(Page::RESCAN_ON_EVACUATION));
+ DCHECK(static_cast<int>(p->parallel_sweeping()) ==
+ MemoryChunk::SWEEPING_DONE);
+ PagedSpace* space = static_cast<PagedSpace*>(p->owner());
+ // Allocate emergency memory for the case when compaction fails due to out
+ // of memory.
+ if (!space->HasEmergencyMemory()) {
+ space->CreateEmergencyMemory();
+ }
+ if (p->IsEvacuationCandidate()) {
+ // During compaction we might have to request a new page. Check that we
+ // have an emergency page and the space still has room for that.
+ if (space->HasEmergencyMemory() && space->CanExpand()) {
+ EvacuateLiveObjectsFromPage(p);
+ } else {
+ // Without room for expansion evacuation is not guaranteed to succeed.
+ // Pessimistically abandon unevacuated pages.
+ for (int j = i; j < npages; j++) {
+ Page* page = evacuation_candidates_[j];
+ slots_buffer_allocator_.DeallocateChain(page->slots_buffer_address());
+ page->ClearEvacuationCandidate();
+ page->SetFlag(Page::RESCAN_ON_EVACUATION);
+ }
+ break;
+ }
+ }
+ }
+ if (npages > 0) {
+ // Release emergency memory.
+ PagedSpaces spaces(heap());
+ for (PagedSpace* space = spaces.next(); space != NULL;
+ space = spaces.next()) {
+ if (space->HasEmergencyMemory()) {
+ space->FreeEmergencyMemory();
+ }
+ }
+ }
+}
+
+
+class EvacuationWeakObjectRetainer : public WeakObjectRetainer {
+ public:
+ virtual Object* RetainAs(Object* object) {
+ if (object->IsHeapObject()) {
+ HeapObject* heap_object = HeapObject::cast(object);
+ MapWord map_word = heap_object->map_word();
+ if (map_word.IsForwardingAddress()) {
+ return map_word.ToForwardingAddress();
+ }
+ }
+ return object;
+ }
+};
+
+
+static inline void UpdateSlot(Isolate* isolate, ObjectVisitor* v,
+ SlotsBuffer::SlotType slot_type, Address addr) {
+ switch (slot_type) {
+ case SlotsBuffer::CODE_TARGET_SLOT: {
+ RelocInfo rinfo(addr, RelocInfo::CODE_TARGET, 0, NULL);
+ rinfo.Visit(isolate, v);
+ break;
+ }
+ case SlotsBuffer::CODE_ENTRY_SLOT: {
+ v->VisitCodeEntry(addr);
+ break;
+ }
+ case SlotsBuffer::RELOCATED_CODE_OBJECT: {
+ HeapObject* obj = HeapObject::FromAddress(addr);
+ Code::cast(obj)->CodeIterateBody(v);
+ break;
+ }
+ case SlotsBuffer::DEBUG_TARGET_SLOT: {
+ RelocInfo rinfo(addr, RelocInfo::DEBUG_BREAK_SLOT, 0, NULL);
+ if (rinfo.IsPatchedDebugBreakSlotSequence()) rinfo.Visit(isolate, v);
+ break;
+ }
+ case SlotsBuffer::JS_RETURN_SLOT: {
+ RelocInfo rinfo(addr, RelocInfo::JS_RETURN, 0, NULL);
+ if (rinfo.IsPatchedReturnSequence()) rinfo.Visit(isolate, v);
+ break;
+ }
+ case SlotsBuffer::EMBEDDED_OBJECT_SLOT: {
+ RelocInfo rinfo(addr, RelocInfo::EMBEDDED_OBJECT, 0, NULL);
+ rinfo.Visit(isolate, v);
+ break;
+ }
+ default:
+ UNREACHABLE();
+ break;
+ }
+}
+
+
+enum SweepingMode { SWEEP_ONLY, SWEEP_AND_VISIT_LIVE_OBJECTS };
+
+
+enum SkipListRebuildingMode { REBUILD_SKIP_LIST, IGNORE_SKIP_LIST };
+
+
+enum FreeSpaceTreatmentMode { IGNORE_FREE_SPACE, ZAP_FREE_SPACE };
+
+
+template <MarkCompactCollector::SweepingParallelism mode>
+static intptr_t Free(PagedSpace* space, FreeList* free_list, Address start,
+ int size) {
+ if (mode == MarkCompactCollector::SWEEP_ON_MAIN_THREAD) {
+ DCHECK(free_list == NULL);
+ return space->Free(start, size);
+ } else {
+ // TODO(hpayer): account for wasted bytes in concurrent sweeping too.
+ return size - free_list->Free(start, size);
+ }
+}
+
+
+// Sweeps a page. After sweeping the page can be iterated.
+// Slots in live objects pointing into evacuation candidates are updated
+// if requested.
+// Returns the size of the biggest continuous freed memory chunk in bytes.
+template <SweepingMode sweeping_mode,
+ MarkCompactCollector::SweepingParallelism parallelism,
+ SkipListRebuildingMode skip_list_mode,
+ FreeSpaceTreatmentMode free_space_mode>
+static int Sweep(PagedSpace* space, FreeList* free_list, Page* p,
+ ObjectVisitor* v) {
+ DCHECK(!p->IsEvacuationCandidate() && !p->WasSwept());
+ DCHECK_EQ(skip_list_mode == REBUILD_SKIP_LIST,
+ space->identity() == CODE_SPACE);
+ DCHECK((p->skip_list() == NULL) || (skip_list_mode == REBUILD_SKIP_LIST));
+ DCHECK(parallelism == MarkCompactCollector::SWEEP_ON_MAIN_THREAD ||
+ sweeping_mode == SWEEP_ONLY);
+
+ Address free_start = p->area_start();
+ DCHECK(reinterpret_cast<intptr_t>(free_start) % (32 * kPointerSize) == 0);
+ int offsets[16];
+
+ SkipList* skip_list = p->skip_list();
+ int curr_region = -1;
+ if ((skip_list_mode == REBUILD_SKIP_LIST) && skip_list) {
+ skip_list->Clear();
+ }
+
+ intptr_t freed_bytes = 0;
+ intptr_t max_freed_bytes = 0;
+
+ for (MarkBitCellIterator it(p); !it.Done(); it.Advance()) {
+ Address cell_base = it.CurrentCellBase();
+ MarkBit::CellType* cell = it.CurrentCell();
+ int live_objects = MarkWordToObjectStarts(*cell, offsets);
+ int live_index = 0;
+ for (; live_objects != 0; live_objects--) {
+ Address free_end = cell_base + offsets[live_index++] * kPointerSize;
+ if (free_end != free_start) {
+ int size = static_cast<int>(free_end - free_start);
+ if (free_space_mode == ZAP_FREE_SPACE) {
+ memset(free_start, 0xcc, size);
+ }
+ freed_bytes = Free<parallelism>(space, free_list, free_start, size);
+ max_freed_bytes = Max(freed_bytes, max_freed_bytes);
+#ifdef ENABLE_GDB_JIT_INTERFACE
+ if (FLAG_gdbjit && space->identity() == CODE_SPACE) {
+ GDBJITInterface::RemoveCodeRange(free_start, free_end);
+ }
+#endif
+ }
+ HeapObject* live_object = HeapObject::FromAddress(free_end);
+ DCHECK(Marking::IsBlack(Marking::MarkBitFrom(live_object)));
+ Map* map = live_object->map();
+ int size = live_object->SizeFromMap(map);
+ if (sweeping_mode == SWEEP_AND_VISIT_LIVE_OBJECTS) {
+ live_object->IterateBody(map->instance_type(), size, v);
+ }
+ if ((skip_list_mode == REBUILD_SKIP_LIST) && skip_list != NULL) {
+ int new_region_start = SkipList::RegionNumber(free_end);
+ int new_region_end =
+ SkipList::RegionNumber(free_end + size - kPointerSize);
+ if (new_region_start != curr_region || new_region_end != curr_region) {
+ skip_list->AddObject(free_end, size);
+ curr_region = new_region_end;
+ }
+ }
+ free_start = free_end + size;
+ }
+ // Clear marking bits for current cell.
+ *cell = 0;
+ }
+ if (free_start != p->area_end()) {
+ int size = static_cast<int>(p->area_end() - free_start);
+ if (free_space_mode == ZAP_FREE_SPACE) {
+ memset(free_start, 0xcc, size);
+ }
+ freed_bytes = Free<parallelism>(space, free_list, free_start, size);
+ max_freed_bytes = Max(freed_bytes, max_freed_bytes);
+#ifdef ENABLE_GDB_JIT_INTERFACE
+ if (FLAG_gdbjit && space->identity() == CODE_SPACE) {
+ GDBJITInterface::RemoveCodeRange(free_start, p->area_end());
+ }
+#endif
+ }
+ p->ResetLiveBytes();
+
+ if (parallelism == MarkCompactCollector::SWEEP_IN_PARALLEL) {
+ // When concurrent sweeping is active, the page will be marked after
+ // sweeping by the main thread.
+ p->set_parallel_sweeping(MemoryChunk::SWEEPING_FINALIZE);
+ } else {
+ p->SetWasSwept();
+ }
+ return FreeList::GuaranteedAllocatable(static_cast<int>(max_freed_bytes));
+}
+
+
+static bool SetMarkBitsUnderInvalidatedCode(Code* code, bool value) {
+ Page* p = Page::FromAddress(code->address());
+
+ if (p->IsEvacuationCandidate() || p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) {
+ return false;
+ }
+
+ Address code_start = code->address();
+ Address code_end = code_start + code->Size();
+
+ uint32_t start_index = MemoryChunk::FastAddressToMarkbitIndex(code_start);
+ uint32_t end_index =
+ MemoryChunk::FastAddressToMarkbitIndex(code_end - kPointerSize);
+
+ Bitmap* b = p->markbits();
+
+ MarkBit start_mark_bit = b->MarkBitFromIndex(start_index);
+ MarkBit end_mark_bit = b->MarkBitFromIndex(end_index);
+
+ MarkBit::CellType* start_cell = start_mark_bit.cell();
+ MarkBit::CellType* end_cell = end_mark_bit.cell();
+
+ if (value) {
+ MarkBit::CellType start_mask = ~(start_mark_bit.mask() - 1);
+ MarkBit::CellType end_mask = (end_mark_bit.mask() << 1) - 1;
+
+ if (start_cell == end_cell) {
+ *start_cell |= start_mask & end_mask;
+ } else {
+ *start_cell |= start_mask;
+ for (MarkBit::CellType* cell = start_cell + 1; cell < end_cell; cell++) {
+ *cell = ~0;
+ }
+ *end_cell |= end_mask;
+ }
+ } else {
+ for (MarkBit::CellType* cell = start_cell; cell <= end_cell; cell++) {
+ *cell = 0;
+ }
+ }
+
+ return true;
+}
+
+
+static bool IsOnInvalidatedCodeObject(Address addr) {
+ // We did not record any slots in large objects thus
+ // we can safely go to the page from the slot address.
+ Page* p = Page::FromAddress(addr);
+
+ // First check owner's identity because old pointer and old data spaces
+ // are swept lazily and might still have non-zero mark-bits on some
+ // pages.
+ if (p->owner()->identity() != CODE_SPACE) return false;
+
+ // In code space only bits on evacuation candidates (but we don't record
+ // any slots on them) and under invalidated code objects are non-zero.
+ MarkBit mark_bit =
+ p->markbits()->MarkBitFromIndex(Page::FastAddressToMarkbitIndex(addr));
+
+ return mark_bit.Get();
+}
+
+
+void MarkCompactCollector::InvalidateCode(Code* code) {
+ if (heap_->incremental_marking()->IsCompacting() &&
+ !ShouldSkipEvacuationSlotRecording(code)) {
+ DCHECK(compacting_);
+
+ // If the object is white than no slots were recorded on it yet.
+ MarkBit mark_bit = Marking::MarkBitFrom(code);
+ if (Marking::IsWhite(mark_bit)) return;
+
+ invalidated_code_.Add(code);
+ }
+}
+
+
+// Return true if the given code is deoptimized or will be deoptimized.
+bool MarkCompactCollector::WillBeDeoptimized(Code* code) {
+ return code->is_optimized_code() && code->marked_for_deoptimization();
+}
+
+
+bool MarkCompactCollector::MarkInvalidatedCode() {
+ bool code_marked = false;
+
+ int length = invalidated_code_.length();
+ for (int i = 0; i < length; i++) {
+ Code* code = invalidated_code_[i];
+
+ if (SetMarkBitsUnderInvalidatedCode(code, true)) {
+ code_marked = true;
+ }
+ }
+
+ return code_marked;
+}
+
+
+void MarkCompactCollector::RemoveDeadInvalidatedCode() {
+ int length = invalidated_code_.length();
+ for (int i = 0; i < length; i++) {
+ if (!IsMarked(invalidated_code_[i])) invalidated_code_[i] = NULL;
+ }
+}
+
+
+void MarkCompactCollector::ProcessInvalidatedCode(ObjectVisitor* visitor) {
+ int length = invalidated_code_.length();
+ for (int i = 0; i < length; i++) {
+ Code* code = invalidated_code_[i];
+ if (code != NULL) {
+ code->Iterate(visitor);
+ SetMarkBitsUnderInvalidatedCode(code, false);
+ }
+ }
+ invalidated_code_.Rewind(0);
+}
+
+
+void MarkCompactCollector::EvacuateNewSpaceAndCandidates() {
+ Heap::RelocationLock relocation_lock(heap());
+
+ bool code_slots_filtering_required;
+ {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_SWEEP_NEWSPACE);
+ code_slots_filtering_required = MarkInvalidatedCode();
+ EvacuateNewSpace();
+ }
+
+ {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_EVACUATE_PAGES);
+ EvacuatePages();
+ }
+
+ // Second pass: find pointers to new space and update them.
+ PointersUpdatingVisitor updating_visitor(heap());
+
+ {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_UPDATE_NEW_TO_NEW_POINTERS);
+ // Update pointers in to space.
+ SemiSpaceIterator to_it(heap()->new_space()->bottom(),
+ heap()->new_space()->top());
+ for (HeapObject* object = to_it.Next(); object != NULL;
+ object = to_it.Next()) {
+ Map* map = object->map();
+ object->IterateBody(map->instance_type(), object->SizeFromMap(map),
+ &updating_visitor);
+ }
+ }
+
+ {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_UPDATE_ROOT_TO_NEW_POINTERS);
+ // Update roots.
+ heap_->IterateRoots(&updating_visitor, VISIT_ALL_IN_SWEEP_NEWSPACE);
+ }
+
+ {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_UPDATE_OLD_TO_NEW_POINTERS);
+ StoreBufferRebuildScope scope(heap_, heap_->store_buffer(),
+ &Heap::ScavengeStoreBufferCallback);
+ heap_->store_buffer()->IteratePointersToNewSpaceAndClearMaps(
+ &UpdatePointer);
+ }
+
+ {
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_UPDATE_POINTERS_TO_EVACUATED);
+ SlotsBuffer::UpdateSlotsRecordedIn(heap_, migration_slots_buffer_,
+ code_slots_filtering_required);
+ if (FLAG_trace_fragmentation) {
+ PrintF(" migration slots buffer: %d\n",
+ SlotsBuffer::SizeOfChain(migration_slots_buffer_));
+ }
+
+ if (compacting_ && was_marked_incrementally_) {
+ // It's difficult to filter out slots recorded for large objects.
+ LargeObjectIterator it(heap_->lo_space());
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ // LargeObjectSpace is not swept yet thus we have to skip
+ // dead objects explicitly.
+ if (!IsMarked(obj)) continue;
+
+ Page* p = Page::FromAddress(obj->address());
+ if (p->IsFlagSet(Page::RESCAN_ON_EVACUATION)) {
+ obj->Iterate(&updating_visitor);
+ p->ClearFlag(Page::RESCAN_ON_EVACUATION);
+ }
+ }
+ }
+ }
+
+ int npages = evacuation_candidates_.length();
+ {
+ GCTracer::Scope gc_scope(
+ heap()->tracer(),
+ GCTracer::Scope::MC_UPDATE_POINTERS_BETWEEN_EVACUATED);
+ for (int i = 0; i < npages; i++) {
+ Page* p = evacuation_candidates_[i];
+ DCHECK(p->IsEvacuationCandidate() ||
+ p->IsFlagSet(Page::RESCAN_ON_EVACUATION));
+
+ if (p->IsEvacuationCandidate()) {
+ SlotsBuffer::UpdateSlotsRecordedIn(heap_, p->slots_buffer(),
+ code_slots_filtering_required);
+ if (FLAG_trace_fragmentation) {
+ PrintF(" page %p slots buffer: %d\n", reinterpret_cast<void*>(p),
+ SlotsBuffer::SizeOfChain(p->slots_buffer()));
+ }
+
+ // Important: skip list should be cleared only after roots were updated
+ // because root iteration traverses the stack and might have to find
+ // code objects from non-updated pc pointing into evacuation candidate.
+ SkipList* list = p->skip_list();
+ if (list != NULL) list->Clear();
+ } else {
+ if (FLAG_gc_verbose) {
+ PrintF("Sweeping 0x%" V8PRIxPTR " during evacuation.\n",
+ reinterpret_cast<intptr_t>(p));
+ }
+ PagedSpace* space = static_cast<PagedSpace*>(p->owner());
+ p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION);
+
+ switch (space->identity()) {
+ case OLD_DATA_SPACE:
+ Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
+ IGNORE_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p,
+ &updating_visitor);
+ break;
+ case OLD_POINTER_SPACE:
+ Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
+ IGNORE_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p,
+ &updating_visitor);
+ break;
+ case CODE_SPACE:
+ if (FLAG_zap_code_space) {
+ Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
+ REBUILD_SKIP_LIST, ZAP_FREE_SPACE>(space, NULL, p,
+ &updating_visitor);
+ } else {
+ Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
+ REBUILD_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p,
+ &updating_visitor);
+ }
+ break;
+ default:
+ UNREACHABLE();
+ break;
+ }
+ }
+ }
+ }
+
+ GCTracer::Scope gc_scope(heap()->tracer(),
+ GCTracer::Scope::MC_UPDATE_MISC_POINTERS);
+
+ // Update pointers from cells.
+ HeapObjectIterator cell_iterator(heap_->cell_space());
+ for (HeapObject* cell = cell_iterator.Next(); cell != NULL;
+ cell = cell_iterator.Next()) {
+ if (cell->IsCell()) {
+ Cell::BodyDescriptor::IterateBody(cell, &updating_visitor);
+ }
+ }
+
+ HeapObjectIterator js_global_property_cell_iterator(
+ heap_->property_cell_space());
+ for (HeapObject* cell = js_global_property_cell_iterator.Next(); cell != NULL;
+ cell = js_global_property_cell_iterator.Next()) {
+ if (cell->IsPropertyCell()) {
+ PropertyCell::BodyDescriptor::IterateBody(cell, &updating_visitor);
+ }
+ }
+
+ heap_->string_table()->Iterate(&updating_visitor);
+ updating_visitor.VisitPointer(heap_->weak_object_to_code_table_address());
+ if (heap_->weak_object_to_code_table()->IsHashTable()) {
+ WeakHashTable* table =
+ WeakHashTable::cast(heap_->weak_object_to_code_table());
+ table->Iterate(&updating_visitor);
+ table->Rehash(heap_->isolate()->factory()->undefined_value());
+ }
+
+ // Update pointers from external string table.
+ heap_->UpdateReferencesInExternalStringTable(
+ &UpdateReferenceInExternalStringTableEntry);
+
+ EvacuationWeakObjectRetainer evacuation_object_retainer;
+ heap()->ProcessWeakReferences(&evacuation_object_retainer);
+
+ // Visit invalidated code (we ignored all slots on it) and clear mark-bits
+ // under it.
+ ProcessInvalidatedCode(&updating_visitor);
+
+ heap_->isolate()->inner_pointer_to_code_cache()->Flush();
+
+ slots_buffer_allocator_.DeallocateChain(&migration_slots_buffer_);
+ DCHECK(migration_slots_buffer_ == NULL);
+}
+
+
+void MarkCompactCollector::MoveEvacuationCandidatesToEndOfPagesList() {
+ int npages = evacuation_candidates_.length();
+ for (int i = 0; i < npages; i++) {
+ Page* p = evacuation_candidates_[i];
+ if (!p->IsEvacuationCandidate()) continue;
+ p->Unlink();
+ PagedSpace* space = static_cast<PagedSpace*>(p->owner());
+ p->InsertAfter(space->LastPage());
+ }
+}
+
+
+void MarkCompactCollector::ReleaseEvacuationCandidates() {
+ int npages = evacuation_candidates_.length();
+ for (int i = 0; i < npages; i++) {
+ Page* p = evacuation_candidates_[i];
+ if (!p->IsEvacuationCandidate()) continue;
+ PagedSpace* space = static_cast<PagedSpace*>(p->owner());
+ space->Free(p->area_start(), p->area_size());
+ p->set_scan_on_scavenge(false);
+ slots_buffer_allocator_.DeallocateChain(p->slots_buffer_address());
+ p->ResetLiveBytes();
+ space->ReleasePage(p);
+ }
+ evacuation_candidates_.Rewind(0);
+ compacting_ = false;
+ heap()->FreeQueuedChunks();
+}
+
+
+static const int kStartTableEntriesPerLine = 5;
+static const int kStartTableLines = 171;
+static const int kStartTableInvalidLine = 127;
+static const int kStartTableUnusedEntry = 126;
+
+#define _ kStartTableUnusedEntry
+#define X kStartTableInvalidLine
+// Mark-bit to object start offset table.
+//
+// The line is indexed by the mark bits in a byte. The first number on
+// the line describes the number of live object starts for the line and the
+// other numbers on the line describe the offsets (in words) of the object
+// starts.
+//
+// Since objects are at least 2 words large we don't have entries for two
+// consecutive 1 bits. All entries after 170 have at least 2 consecutive bits.
+char kStartTable[kStartTableLines * kStartTableEntriesPerLine] = {
+ 0, _, _,
+ _, _, // 0
+ 1, 0, _,
+ _, _, // 1
+ 1, 1, _,
+ _, _, // 2
+ X, _, _,
+ _, _, // 3
+ 1, 2, _,
+ _, _, // 4
+ 2, 0, 2,
+ _, _, // 5
+ X, _, _,
+ _, _, // 6
+ X, _, _,
+ _, _, // 7
+ 1, 3, _,
+ _, _, // 8
+ 2, 0, 3,
+ _, _, // 9
+ 2, 1, 3,
+ _, _, // 10
+ X, _, _,
+ _, _, // 11
+ X, _, _,
+ _, _, // 12
+ X, _, _,
+ _, _, // 13
+ X, _, _,
+ _, _, // 14
+ X, _, _,
+ _, _, // 15
+ 1, 4, _,
+ _, _, // 16
+ 2, 0, 4,
+ _, _, // 17
+ 2, 1, 4,
+ _, _, // 18
+ X, _, _,
+ _, _, // 19
+ 2, 2, 4,
+ _, _, // 20
+ 3, 0, 2,
+ 4, _, // 21
+ X, _, _,
+ _, _, // 22
+ X, _, _,
+ _, _, // 23
+ X, _, _,
+ _, _, // 24
+ X, _, _,
+ _, _, // 25
+ X, _, _,
+ _, _, // 26
+ X, _, _,
+ _, _, // 27
+ X, _, _,
+ _, _, // 28
+ X, _, _,
+ _, _, // 29
+ X, _, _,
+ _, _, // 30
+ X, _, _,
+ _, _, // 31
+ 1, 5, _,
+ _, _, // 32
+ 2, 0, 5,
+ _, _, // 33
+ 2, 1, 5,
+ _, _, // 34
+ X, _, _,
+ _, _, // 35
+ 2, 2, 5,
+ _, _, // 36
+ 3, 0, 2,
+ 5, _, // 37
+ X, _, _,
+ _, _, // 38
+ X, _, _,
+ _, _, // 39
+ 2, 3, 5,
+ _, _, // 40
+ 3, 0, 3,
+ 5, _, // 41
+ 3, 1, 3,
+ 5, _, // 42
+ X, _, _,
+ _, _, // 43
+ X, _, _,
+ _, _, // 44
+ X, _, _,
+ _, _, // 45
+ X, _, _,
+ _, _, // 46
+ X, _, _,
+ _, _, // 47
+ X, _, _,
+ _, _, // 48
+ X, _, _,
+ _, _, // 49
+ X, _, _,
+ _, _, // 50
+ X, _, _,
+ _, _, // 51
+ X, _, _,
+ _, _, // 52
+ X, _, _,
+ _, _, // 53
+ X, _, _,
+ _, _, // 54
+ X, _, _,
+ _, _, // 55
+ X, _, _,
+ _, _, // 56
+ X, _, _,
+ _, _, // 57
+ X, _, _,
+ _, _, // 58
+ X, _, _,
+ _, _, // 59
+ X, _, _,
+ _, _, // 60
+ X, _, _,
+ _, _, // 61
+ X, _, _,
+ _, _, // 62
+ X, _, _,
+ _, _, // 63
+ 1, 6, _,
+ _, _, // 64
+ 2, 0, 6,
+ _, _, // 65
+ 2, 1, 6,
+ _, _, // 66
+ X, _, _,
+ _, _, // 67
+ 2, 2, 6,
+ _, _, // 68
+ 3, 0, 2,
+ 6, _, // 69
+ X, _, _,
+ _, _, // 70
+ X, _, _,
+ _, _, // 71
+ 2, 3, 6,
+ _, _, // 72
+ 3, 0, 3,
+ 6, _, // 73
+ 3, 1, 3,
+ 6, _, // 74
+ X, _, _,
+ _, _, // 75
+ X, _, _,
+ _, _, // 76
+ X, _, _,
+ _, _, // 77
+ X, _, _,
+ _, _, // 78
+ X, _, _,
+ _, _, // 79
+ 2, 4, 6,
+ _, _, // 80
+ 3, 0, 4,
+ 6, _, // 81
+ 3, 1, 4,
+ 6, _, // 82
+ X, _, _,
+ _, _, // 83
+ 3, 2, 4,
+ 6, _, // 84
+ 4, 0, 2,
+ 4, 6, // 85
+ X, _, _,
+ _, _, // 86
+ X, _, _,
+ _, _, // 87
+ X, _, _,
+ _, _, // 88
+ X, _, _,
+ _, _, // 89
+ X, _, _,
+ _, _, // 90
+ X, _, _,
+ _, _, // 91
+ X, _, _,
+ _, _, // 92
+ X, _, _,
+ _, _, // 93
+ X, _, _,
+ _, _, // 94
+ X, _, _,
+ _, _, // 95
+ X, _, _,
+ _, _, // 96
+ X, _, _,
+ _, _, // 97
+ X, _, _,
+ _, _, // 98
+ X, _, _,
+ _, _, // 99
+ X, _, _,
+ _, _, // 100
+ X, _, _,
+ _, _, // 101
+ X, _, _,
+ _, _, // 102
+ X, _, _,
+ _, _, // 103
+ X, _, _,
+ _, _, // 104
+ X, _, _,
+ _, _, // 105
+ X, _, _,
+ _, _, // 106
+ X, _, _,
+ _, _, // 107
+ X, _, _,
+ _, _, // 108
+ X, _, _,
+ _, _, // 109
+ X, _, _,
+ _, _, // 110
+ X, _, _,
+ _, _, // 111
+ X, _, _,
+ _, _, // 112
+ X, _, _,
+ _, _, // 113
+ X, _, _,
+ _, _, // 114
+ X, _, _,
+ _, _, // 115
+ X, _, _,
+ _, _, // 116
+ X, _, _,
+ _, _, // 117
+ X, _, _,
+ _, _, // 118
+ X, _, _,
+ _, _, // 119
+ X, _, _,
+ _, _, // 120
+ X, _, _,
+ _, _, // 121
+ X, _, _,
+ _, _, // 122
+ X, _, _,
+ _, _, // 123
+ X, _, _,
+ _, _, // 124
+ X, _, _,
+ _, _, // 125
+ X, _, _,
+ _, _, // 126
+ X, _, _,
+ _, _, // 127
+ 1, 7, _,
+ _, _, // 128
+ 2, 0, 7,
+ _, _, // 129
+ 2, 1, 7,
+ _, _, // 130
+ X, _, _,
+ _, _, // 131
+ 2, 2, 7,
+ _, _, // 132
+ 3, 0, 2,
+ 7, _, // 133
+ X, _, _,
+ _, _, // 134
+ X, _, _,
+ _, _, // 135
+ 2, 3, 7,
+ _, _, // 136
+ 3, 0, 3,
+ 7, _, // 137
+ 3, 1, 3,
+ 7, _, // 138
+ X, _, _,
+ _, _, // 139
+ X, _, _,
+ _, _, // 140
+ X, _, _,
+ _, _, // 141
+ X, _, _,
+ _, _, // 142
+ X, _, _,
+ _, _, // 143
+ 2, 4, 7,
+ _, _, // 144
+ 3, 0, 4,
+ 7, _, // 145
+ 3, 1, 4,
+ 7, _, // 146
+ X, _, _,
+ _, _, // 147
+ 3, 2, 4,
+ 7, _, // 148
+ 4, 0, 2,
+ 4, 7, // 149
+ X, _, _,
+ _, _, // 150
+ X, _, _,
+ _, _, // 151
+ X, _, _,
+ _, _, // 152
+ X, _, _,
+ _, _, // 153
+ X, _, _,
+ _, _, // 154
+ X, _, _,
+ _, _, // 155
+ X, _, _,
+ _, _, // 156
+ X, _, _,
+ _, _, // 157
+ X, _, _,
+ _, _, // 158
+ X, _, _,
+ _, _, // 159
+ 2, 5, 7,
+ _, _, // 160
+ 3, 0, 5,
+ 7, _, // 161
+ 3, 1, 5,
+ 7, _, // 162
+ X, _, _,
+ _, _, // 163
+ 3, 2, 5,
+ 7, _, // 164
+ 4, 0, 2,
+ 5, 7, // 165
+ X, _, _,
+ _, _, // 166
+ X, _, _,
+ _, _, // 167
+ 3, 3, 5,
+ 7, _, // 168
+ 4, 0, 3,
+ 5, 7, // 169
+ 4, 1, 3,
+ 5, 7 // 170
+};
+#undef _
+#undef X
+
+
+// Takes a word of mark bits. Returns the number of objects that start in the
+// range. Puts the offsets of the words in the supplied array.
+static inline int MarkWordToObjectStarts(uint32_t mark_bits, int* starts) {
+ int objects = 0;
+ int offset = 0;
+
+ // No consecutive 1 bits.
+ DCHECK((mark_bits & 0x180) != 0x180);
+ DCHECK((mark_bits & 0x18000) != 0x18000);
+ DCHECK((mark_bits & 0x1800000) != 0x1800000);
+
+ while (mark_bits != 0) {
+ int byte = (mark_bits & 0xff);
+ mark_bits >>= 8;
+ if (byte != 0) {
+ DCHECK(byte < kStartTableLines); // No consecutive 1 bits.
+ char* table = kStartTable + byte * kStartTableEntriesPerLine;
+ int objects_in_these_8_words = table[0];
+ DCHECK(objects_in_these_8_words != kStartTableInvalidLine);
+ DCHECK(objects_in_these_8_words < kStartTableEntriesPerLine);
+ for (int i = 0; i < objects_in_these_8_words; i++) {
+ starts[objects++] = offset + table[1 + i];
+ }
+ }
+ offset += 8;
+ }
+ return objects;
+}
+
+
+int MarkCompactCollector::SweepInParallel(PagedSpace* space,
+ int required_freed_bytes) {
+ int max_freed = 0;
+ int max_freed_overall = 0;
+ PageIterator it(space);
+ while (it.has_next()) {
+ Page* p = it.next();
+ max_freed = SweepInParallel(p, space);
+ DCHECK(max_freed >= 0);
+ if (required_freed_bytes > 0 && max_freed >= required_freed_bytes) {
+ return max_freed;
+ }
+ max_freed_overall = Max(max_freed, max_freed_overall);
+ if (p == space->end_of_unswept_pages()) break;
+ }
+ return max_freed_overall;
+}
+
+
+int MarkCompactCollector::SweepInParallel(Page* page, PagedSpace* space) {
+ int max_freed = 0;
+ if (page->TryParallelSweeping()) {
+ FreeList* free_list = space == heap()->old_pointer_space()
+ ? free_list_old_pointer_space_.get()
+ : free_list_old_data_space_.get();
+ FreeList private_free_list(space);
+ max_freed = Sweep<SWEEP_ONLY, SWEEP_IN_PARALLEL, IGNORE_SKIP_LIST,
+ IGNORE_FREE_SPACE>(space, &private_free_list, page, NULL);
+ free_list->Concatenate(&private_free_list);
+ }
+ return max_freed;
+}
+
+
+void MarkCompactCollector::SweepSpace(PagedSpace* space, SweeperType sweeper) {
+ space->ClearStats();
+
+ // We defensively initialize end_of_unswept_pages_ here with the first page
+ // of the pages list.
+ space->set_end_of_unswept_pages(space->FirstPage());
+
+ PageIterator it(space);
+
+ int pages_swept = 0;
+ bool unused_page_present = false;
+ bool parallel_sweeping_active = false;
+
+ while (it.has_next()) {
+ Page* p = it.next();
+ DCHECK(p->parallel_sweeping() == MemoryChunk::SWEEPING_DONE);
+
+ // Clear sweeping flags indicating that marking bits are still intact.
+ p->ClearWasSwept();
+
+ if (p->IsFlagSet(Page::RESCAN_ON_EVACUATION) ||
+ p->IsEvacuationCandidate()) {
+ // Will be processed in EvacuateNewSpaceAndCandidates.
+ DCHECK(evacuation_candidates_.length() > 0);
+ continue;
+ }
+
+ // One unused page is kept, all further are released before sweeping them.
+ if (p->LiveBytes() == 0) {
+ if (unused_page_present) {
+ if (FLAG_gc_verbose) {
+ PrintF("Sweeping 0x%" V8PRIxPTR " released page.\n",
+ reinterpret_cast<intptr_t>(p));
+ }
+ // Adjust unswept free bytes because releasing a page expects said
+ // counter to be accurate for unswept pages.
+ space->IncreaseUnsweptFreeBytes(p);
+ space->ReleasePage(p);
+ continue;
+ }
+ unused_page_present = true;
+ }
+
+ switch (sweeper) {
+ case CONCURRENT_SWEEPING:
+ case PARALLEL_SWEEPING:
+ if (!parallel_sweeping_active) {
+ if (FLAG_gc_verbose) {
+ PrintF("Sweeping 0x%" V8PRIxPTR ".\n",
+ reinterpret_cast<intptr_t>(p));
+ }
+ Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, IGNORE_SKIP_LIST,
+ IGNORE_FREE_SPACE>(space, NULL, p, NULL);
+ pages_swept++;
+ parallel_sweeping_active = true;
+ } else {
+ if (FLAG_gc_verbose) {
+ PrintF("Sweeping 0x%" V8PRIxPTR " in parallel.\n",
+ reinterpret_cast<intptr_t>(p));
+ }
+ p->set_parallel_sweeping(MemoryChunk::SWEEPING_PENDING);
+ space->IncreaseUnsweptFreeBytes(p);
+ }
+ space->set_end_of_unswept_pages(p);
+ break;
+ case SEQUENTIAL_SWEEPING: {
+ if (FLAG_gc_verbose) {
+ PrintF("Sweeping 0x%" V8PRIxPTR ".\n", reinterpret_cast<intptr_t>(p));
+ }
+ if (space->identity() == CODE_SPACE && FLAG_zap_code_space) {
+ Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, REBUILD_SKIP_LIST,
+ ZAP_FREE_SPACE>(space, NULL, p, NULL);
+ } else if (space->identity() == CODE_SPACE) {
+ Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, REBUILD_SKIP_LIST,
+ IGNORE_FREE_SPACE>(space, NULL, p, NULL);
+ } else {
+ Sweep<SWEEP_ONLY, SWEEP_ON_MAIN_THREAD, IGNORE_SKIP_LIST,
+ IGNORE_FREE_SPACE>(space, NULL, p, NULL);
+ }
+ pages_swept++;
+ break;
+ }
+ default: { UNREACHABLE(); }
+ }
+ }
+
+ if (FLAG_gc_verbose) {
+ PrintF("SweepSpace: %s (%d pages swept)\n",
+ AllocationSpaceName(space->identity()), pages_swept);
+ }
+
+ // Give pages that are queued to be freed back to the OS.
+ heap()->FreeQueuedChunks();
+}
+
+
+static bool ShouldStartSweeperThreads(MarkCompactCollector::SweeperType type) {
+ return type == MarkCompactCollector::PARALLEL_SWEEPING ||
+ type == MarkCompactCollector::CONCURRENT_SWEEPING;
+}
+
+
+static bool ShouldWaitForSweeperThreads(
+ MarkCompactCollector::SweeperType type) {
+ return type == MarkCompactCollector::PARALLEL_SWEEPING;
+}
+
+
+void MarkCompactCollector::SweepSpaces() {
+ GCTracer::Scope gc_scope(heap()->tracer(), GCTracer::Scope::MC_SWEEP);
+ double start_time = 0.0;
+ if (FLAG_print_cumulative_gc_stat) {
+ start_time = base::OS::TimeCurrentMillis();
+ }
+
+#ifdef DEBUG
+ state_ = SWEEP_SPACES;
+#endif
+ SweeperType how_to_sweep = CONCURRENT_SWEEPING;
+ if (FLAG_parallel_sweeping) how_to_sweep = PARALLEL_SWEEPING;
+ if (FLAG_concurrent_sweeping) how_to_sweep = CONCURRENT_SWEEPING;
+
+ MoveEvacuationCandidatesToEndOfPagesList();
+
+ // Noncompacting collections simply sweep the spaces to clear the mark
+ // bits and free the nonlive blocks (for old and map spaces). We sweep
+ // the map space last because freeing non-live maps overwrites them and
+ // the other spaces rely on possibly non-live maps to get the sizes for
+ // non-live objects.
+ {
+ GCTracer::Scope sweep_scope(heap()->tracer(),
+ GCTracer::Scope::MC_SWEEP_OLDSPACE);
+ {
+ SequentialSweepingScope scope(this);
+ SweepSpace(heap()->old_pointer_space(), how_to_sweep);
+ SweepSpace(heap()->old_data_space(), how_to_sweep);
+ }
+
+ if (ShouldStartSweeperThreads(how_to_sweep)) {
+ StartSweeperThreads();
+ }
+
+ if (ShouldWaitForSweeperThreads(how_to_sweep)) {
+ EnsureSweepingCompleted();
+ }
+ }
+ RemoveDeadInvalidatedCode();
+
+ {
+ GCTracer::Scope sweep_scope(heap()->tracer(),
+ GCTracer::Scope::MC_SWEEP_CODE);
+ SweepSpace(heap()->code_space(), SEQUENTIAL_SWEEPING);
+ }
+
+ {
+ GCTracer::Scope sweep_scope(heap()->tracer(),
+ GCTracer::Scope::MC_SWEEP_CELL);
+ SweepSpace(heap()->cell_space(), SEQUENTIAL_SWEEPING);
+ SweepSpace(heap()->property_cell_space(), SEQUENTIAL_SWEEPING);
+ }
+
+ EvacuateNewSpaceAndCandidates();
+
+ // ClearNonLiveTransitions depends on precise sweeping of map space to
+ // detect whether unmarked map became dead in this collection or in one
+ // of the previous ones.
+ {
+ GCTracer::Scope sweep_scope(heap()->tracer(),
+ GCTracer::Scope::MC_SWEEP_MAP);
+ SweepSpace(heap()->map_space(), SEQUENTIAL_SWEEPING);
+ }
+
+ // Deallocate unmarked objects and clear marked bits for marked objects.
+ heap_->lo_space()->FreeUnmarkedObjects();
+
+ // Deallocate evacuated candidate pages.
+ ReleaseEvacuationCandidates();
+
+ if (FLAG_print_cumulative_gc_stat) {
+ heap_->tracer()->AddSweepingTime(base::OS::TimeCurrentMillis() -
+ start_time);
+ }
+}
+
+
+void MarkCompactCollector::ParallelSweepSpaceComplete(PagedSpace* space) {
+ PageIterator it(space);
+ while (it.has_next()) {
+ Page* p = it.next();
+ if (p->parallel_sweeping() == MemoryChunk::SWEEPING_FINALIZE) {
+ p->set_parallel_sweeping(MemoryChunk::SWEEPING_DONE);
+ p->SetWasSwept();
+ }
+ DCHECK(p->parallel_sweeping() == MemoryChunk::SWEEPING_DONE);
+ }
+}
+
+
+void MarkCompactCollector::ParallelSweepSpacesComplete() {
+ ParallelSweepSpaceComplete(heap()->old_pointer_space());
+ ParallelSweepSpaceComplete(heap()->old_data_space());
+}
+
+
+void MarkCompactCollector::EnableCodeFlushing(bool enable) {
+ if (isolate()->debug()->is_loaded() ||
+ isolate()->debug()->has_break_points()) {
+ enable = false;
+ }
+
+ if (enable) {
+ if (code_flusher_ != NULL) return;
+ code_flusher_ = new CodeFlusher(isolate());
+ } else {
+ if (code_flusher_ == NULL) return;
+ code_flusher_->EvictAllCandidates();
+ delete code_flusher_;
+ code_flusher_ = NULL;
+ }
+
+ if (FLAG_trace_code_flushing) {
+ PrintF("[code-flushing is now %s]\n", enable ? "on" : "off");
+ }
+}
+
+
+// TODO(1466) ReportDeleteIfNeeded is not called currently.
+// Our profiling tools do not expect intersections between
+// code objects. We should either reenable it or change our tools.
+void MarkCompactCollector::ReportDeleteIfNeeded(HeapObject* obj,
+ Isolate* isolate) {
+ if (obj->IsCode()) {
+ PROFILE(isolate, CodeDeleteEvent(obj->address()));
+ }
+}
+
+
+Isolate* MarkCompactCollector::isolate() const { return heap_->isolate(); }
+
+
+void MarkCompactCollector::Initialize() {
+ MarkCompactMarkingVisitor::Initialize();
+ IncrementalMarking::Initialize();
+}
+
+
+bool SlotsBuffer::IsTypedSlot(ObjectSlot slot) {
+ return reinterpret_cast<uintptr_t>(slot) < NUMBER_OF_SLOT_TYPES;
+}
+
+
+bool SlotsBuffer::AddTo(SlotsBufferAllocator* allocator,
+ SlotsBuffer** buffer_address, SlotType type,
+ Address addr, AdditionMode mode) {
+ SlotsBuffer* buffer = *buffer_address;
+ if (buffer == NULL || !buffer->HasSpaceForTypedSlot()) {
+ if (mode == FAIL_ON_OVERFLOW && ChainLengthThresholdReached(buffer)) {
+ allocator->DeallocateChain(buffer_address);
+ return false;
+ }
+ buffer = allocator->AllocateBuffer(buffer);
+ *buffer_address = buffer;
+ }
+ DCHECK(buffer->HasSpaceForTypedSlot());
+ buffer->Add(reinterpret_cast<ObjectSlot>(type));
+ buffer->Add(reinterpret_cast<ObjectSlot>(addr));
+ return true;
+}
+
+
+static inline SlotsBuffer::SlotType SlotTypeForRMode(RelocInfo::Mode rmode) {
+ if (RelocInfo::IsCodeTarget(rmode)) {
+ return SlotsBuffer::CODE_TARGET_SLOT;
+ } else if (RelocInfo::IsEmbeddedObject(rmode)) {
+ return SlotsBuffer::EMBEDDED_OBJECT_SLOT;
+ } else if (RelocInfo::IsDebugBreakSlot(rmode)) {
+ return SlotsBuffer::DEBUG_TARGET_SLOT;
+ } else if (RelocInfo::IsJSReturn(rmode)) {
+ return SlotsBuffer::JS_RETURN_SLOT;
+ }
+ UNREACHABLE();
+ return SlotsBuffer::NUMBER_OF_SLOT_TYPES;
+}
+
+
+void MarkCompactCollector::RecordRelocSlot(RelocInfo* rinfo, Object* target) {
+ Page* target_page = Page::FromAddress(reinterpret_cast<Address>(target));
+ RelocInfo::Mode rmode = rinfo->rmode();
+ if (target_page->IsEvacuationCandidate() &&
+ (rinfo->host() == NULL ||
+ !ShouldSkipEvacuationSlotRecording(rinfo->host()))) {
+ bool success;
+ if (RelocInfo::IsEmbeddedObject(rmode) && rinfo->IsInConstantPool()) {
+ // This doesn't need to be typed since it is just a normal heap pointer.
+ Object** target_pointer =
+ reinterpret_cast<Object**>(rinfo->constant_pool_entry_address());
+ success = SlotsBuffer::AddTo(
+ &slots_buffer_allocator_, target_page->slots_buffer_address(),
+ target_pointer, SlotsBuffer::FAIL_ON_OVERFLOW);
+ } else if (RelocInfo::IsCodeTarget(rmode) && rinfo->IsInConstantPool()) {
+ success = SlotsBuffer::AddTo(
+ &slots_buffer_allocator_, target_page->slots_buffer_address(),
+ SlotsBuffer::CODE_ENTRY_SLOT, rinfo->constant_pool_entry_address(),
+ SlotsBuffer::FAIL_ON_OVERFLOW);
+ } else {
+ success = SlotsBuffer::AddTo(
+ &slots_buffer_allocator_, target_page->slots_buffer_address(),
+ SlotTypeForRMode(rmode), rinfo->pc(), SlotsBuffer::FAIL_ON_OVERFLOW);
+ }
+ if (!success) {
+ EvictEvacuationCandidate(target_page);
+ }
+ }
+}
+
+
+void MarkCompactCollector::RecordCodeEntrySlot(Address slot, Code* target) {
+ Page* target_page = Page::FromAddress(reinterpret_cast<Address>(target));
+ if (target_page->IsEvacuationCandidate() &&
+ !ShouldSkipEvacuationSlotRecording(reinterpret_cast<Object**>(slot))) {
+ if (!SlotsBuffer::AddTo(&slots_buffer_allocator_,
+ target_page->slots_buffer_address(),
+ SlotsBuffer::CODE_ENTRY_SLOT, slot,
+ SlotsBuffer::FAIL_ON_OVERFLOW)) {
+ EvictEvacuationCandidate(target_page);
+ }
+ }
+}
+
+
+void MarkCompactCollector::RecordCodeTargetPatch(Address pc, Code* target) {
+ DCHECK(heap()->gc_state() == Heap::MARK_COMPACT);
+ if (is_compacting()) {
+ Code* host =
+ isolate()->inner_pointer_to_code_cache()->GcSafeFindCodeForInnerPointer(
+ pc);
+ MarkBit mark_bit = Marking::MarkBitFrom(host);
+ if (Marking::IsBlack(mark_bit)) {
+ RelocInfo rinfo(pc, RelocInfo::CODE_TARGET, 0, host);
+ RecordRelocSlot(&rinfo, target);
+ }
+ }
+}
+
+
+static inline SlotsBuffer::SlotType DecodeSlotType(
+ SlotsBuffer::ObjectSlot slot) {
+ return static_cast<SlotsBuffer::SlotType>(reinterpret_cast<intptr_t>(slot));
+}
+
+
+void SlotsBuffer::UpdateSlots(Heap* heap) {
+ PointersUpdatingVisitor v(heap);
+
+ for (int slot_idx = 0; slot_idx < idx_; ++slot_idx) {
+ ObjectSlot slot = slots_[slot_idx];
+ if (!IsTypedSlot(slot)) {
+ PointersUpdatingVisitor::UpdateSlot(heap, slot);
+ } else {
+ ++slot_idx;
+ DCHECK(slot_idx < idx_);
+ UpdateSlot(heap->isolate(), &v, DecodeSlotType(slot),
+ reinterpret_cast<Address>(slots_[slot_idx]));
+ }
+ }
+}
+
+
+void SlotsBuffer::UpdateSlotsWithFilter(Heap* heap) {
+ PointersUpdatingVisitor v(heap);
+
+ for (int slot_idx = 0; slot_idx < idx_; ++slot_idx) {
+ ObjectSlot slot = slots_[slot_idx];
+ if (!IsTypedSlot(slot)) {
+ if (!IsOnInvalidatedCodeObject(reinterpret_cast<Address>(slot))) {
+ PointersUpdatingVisitor::UpdateSlot(heap, slot);
+ }
+ } else {
+ ++slot_idx;
+ DCHECK(slot_idx < idx_);
+ Address pc = reinterpret_cast<Address>(slots_[slot_idx]);
+ if (!IsOnInvalidatedCodeObject(pc)) {
+ UpdateSlot(heap->isolate(), &v, DecodeSlotType(slot),
+ reinterpret_cast<Address>(slots_[slot_idx]));
+ }
+ }
+ }
+}
+
+
+SlotsBuffer* SlotsBufferAllocator::AllocateBuffer(SlotsBuffer* next_buffer) {
+ return new SlotsBuffer(next_buffer);
+}
+
+
+void SlotsBufferAllocator::DeallocateBuffer(SlotsBuffer* buffer) {
+ delete buffer;
+}
+
+
+void SlotsBufferAllocator::DeallocateChain(SlotsBuffer** buffer_address) {
+ SlotsBuffer* buffer = *buffer_address;
+ while (buffer != NULL) {
+ SlotsBuffer* next_buffer = buffer->next();
+ DeallocateBuffer(buffer);
+ buffer = next_buffer;
+ }
+ *buffer_address = NULL;
+}
+}
+} // namespace v8::internal
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
new file mode 100644
index 0000000..c5087b4
--- /dev/null
+++ b/src/heap/mark-compact.h
@@ -0,0 +1,956 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_MARK_COMPACT_H_
+#define V8_HEAP_MARK_COMPACT_H_
+
+#include "src/base/bits.h"
+#include "src/heap/spaces.h"
+
+namespace v8 {
+namespace internal {
+
+// Callback function, returns whether an object is alive. The heap size
+// of the object is returned in size. It optionally updates the offset
+// to the first live object in the page (only used for old and map objects).
+typedef bool (*IsAliveFunction)(HeapObject* obj, int* size, int* offset);
+
+// Forward declarations.
+class CodeFlusher;
+class MarkCompactCollector;
+class MarkingVisitor;
+class RootMarkingVisitor;
+
+
+class Marking {
+ public:
+ explicit Marking(Heap* heap) : heap_(heap) {}
+
+ INLINE(static MarkBit MarkBitFrom(Address addr));
+
+ INLINE(static MarkBit MarkBitFrom(HeapObject* obj)) {
+ return MarkBitFrom(reinterpret_cast<Address>(obj));
+ }
+
+ // Impossible markbits: 01
+ static const char* kImpossibleBitPattern;
+ INLINE(static bool IsImpossible(MarkBit mark_bit)) {
+ return !mark_bit.Get() && mark_bit.Next().Get();
+ }
+
+ // Black markbits: 10 - this is required by the sweeper.
+ static const char* kBlackBitPattern;
+ INLINE(static bool IsBlack(MarkBit mark_bit)) {
+ return mark_bit.Get() && !mark_bit.Next().Get();
+ }
+
+ // White markbits: 00 - this is required by the mark bit clearer.
+ static const char* kWhiteBitPattern;
+ INLINE(static bool IsWhite(MarkBit mark_bit)) { return !mark_bit.Get(); }
+
+ // Grey markbits: 11
+ static const char* kGreyBitPattern;
+ INLINE(static bool IsGrey(MarkBit mark_bit)) {
+ return mark_bit.Get() && mark_bit.Next().Get();
+ }
+
+ INLINE(static void MarkBlack(MarkBit mark_bit)) {
+ mark_bit.Set();
+ mark_bit.Next().Clear();
+ }
+
+ INLINE(static void BlackToGrey(MarkBit markbit)) { markbit.Next().Set(); }
+
+ INLINE(static void WhiteToGrey(MarkBit markbit)) {
+ markbit.Set();
+ markbit.Next().Set();
+ }
+
+ INLINE(static void GreyToBlack(MarkBit markbit)) { markbit.Next().Clear(); }
+
+ INLINE(static void BlackToGrey(HeapObject* obj)) {
+ BlackToGrey(MarkBitFrom(obj));
+ }
+
+ INLINE(static void AnyToGrey(MarkBit markbit)) {
+ markbit.Set();
+ markbit.Next().Set();
+ }
+
+ void TransferMark(Address old_start, Address new_start);
+
+#ifdef DEBUG
+ enum ObjectColor {
+ BLACK_OBJECT,
+ WHITE_OBJECT,
+ GREY_OBJECT,
+ IMPOSSIBLE_COLOR
+ };
+
+ static const char* ColorName(ObjectColor color) {
+ switch (color) {
+ case BLACK_OBJECT:
+ return "black";
+ case WHITE_OBJECT:
+ return "white";
+ case GREY_OBJECT:
+ return "grey";
+ case IMPOSSIBLE_COLOR:
+ return "impossible";
+ }
+ return "error";
+ }
+
+ static ObjectColor Color(HeapObject* obj) {
+ return Color(Marking::MarkBitFrom(obj));
+ }
+
+ static ObjectColor Color(MarkBit mark_bit) {
+ if (IsBlack(mark_bit)) return BLACK_OBJECT;
+ if (IsWhite(mark_bit)) return WHITE_OBJECT;
+ if (IsGrey(mark_bit)) return GREY_OBJECT;
+ UNREACHABLE();
+ return IMPOSSIBLE_COLOR;
+ }
+#endif
+
+ // Returns true if the transferred color is black.
+ INLINE(static bool TransferColor(HeapObject* from, HeapObject* to)) {
+ MarkBit from_mark_bit = MarkBitFrom(from);
+ MarkBit to_mark_bit = MarkBitFrom(to);
+ bool is_black = false;
+ if (from_mark_bit.Get()) {
+ to_mark_bit.Set();
+ is_black = true; // Looks black so far.
+ }
+ if (from_mark_bit.Next().Get()) {
+ to_mark_bit.Next().Set();
+ is_black = false; // Was actually gray.
+ }
+ return is_black;
+ }
+
+ private:
+ Heap* heap_;
+};
+
+// ----------------------------------------------------------------------------
+// Marking deque for tracing live objects.
+class MarkingDeque {
+ public:
+ MarkingDeque()
+ : array_(NULL), top_(0), bottom_(0), mask_(0), overflowed_(false) {}
+
+ void Initialize(Address low, Address high) {
+ HeapObject** obj_low = reinterpret_cast<HeapObject**>(low);
+ HeapObject** obj_high = reinterpret_cast<HeapObject**>(high);
+ array_ = obj_low;
+ mask_ = base::bits::RoundDownToPowerOfTwo32(
+ static_cast<uint32_t>(obj_high - obj_low)) -
+ 1;
+ top_ = bottom_ = 0;
+ overflowed_ = false;
+ }
+
+ inline bool IsFull() { return ((top_ + 1) & mask_) == bottom_; }
+
+ inline bool IsEmpty() { return top_ == bottom_; }
+
+ bool overflowed() const { return overflowed_; }
+
+ void ClearOverflowed() { overflowed_ = false; }
+
+ void SetOverflowed() { overflowed_ = true; }
+
+ // Push the (marked) object on the marking stack if there is room,
+ // otherwise mark the object as overflowed and wait for a rescan of the
+ // heap.
+ INLINE(void PushBlack(HeapObject* object)) {
+ DCHECK(object->IsHeapObject());
+ if (IsFull()) {
+ Marking::BlackToGrey(object);
+ MemoryChunk::IncrementLiveBytesFromGC(object->address(), -object->Size());
+ SetOverflowed();
+ } else {
+ array_[top_] = object;
+ top_ = ((top_ + 1) & mask_);
+ }
+ }
+
+ INLINE(void PushGrey(HeapObject* object)) {
+ DCHECK(object->IsHeapObject());
+ if (IsFull()) {
+ SetOverflowed();
+ } else {
+ array_[top_] = object;
+ top_ = ((top_ + 1) & mask_);
+ }
+ }
+
+ INLINE(HeapObject* Pop()) {
+ DCHECK(!IsEmpty());
+ top_ = ((top_ - 1) & mask_);
+ HeapObject* object = array_[top_];
+ DCHECK(object->IsHeapObject());
+ return object;
+ }
+
+ INLINE(void UnshiftGrey(HeapObject* object)) {
+ DCHECK(object->IsHeapObject());
+ if (IsFull()) {
+ SetOverflowed();
+ } else {
+ bottom_ = ((bottom_ - 1) & mask_);
+ array_[bottom_] = object;
+ }
+ }
+
+ HeapObject** array() { return array_; }
+ int bottom() { return bottom_; }
+ int top() { return top_; }
+ int mask() { return mask_; }
+ void set_top(int top) { top_ = top; }
+
+ private:
+ HeapObject** array_;
+ // array_[(top - 1) & mask_] is the top element in the deque. The Deque is
+ // empty when top_ == bottom_. It is full when top_ + 1 == bottom
+ // (mod mask + 1).
+ int top_;
+ int bottom_;
+ int mask_;
+ bool overflowed_;
+
+ DISALLOW_COPY_AND_ASSIGN(MarkingDeque);
+};
+
+
+class SlotsBufferAllocator {
+ public:
+ SlotsBuffer* AllocateBuffer(SlotsBuffer* next_buffer);
+ void DeallocateBuffer(SlotsBuffer* buffer);
+
+ void DeallocateChain(SlotsBuffer** buffer_address);
+};
+
+
+// SlotsBuffer records a sequence of slots that has to be updated
+// after live objects were relocated from evacuation candidates.
+// All slots are either untyped or typed:
+// - Untyped slots are expected to contain a tagged object pointer.
+// They are recorded by an address.
+// - Typed slots are expected to contain an encoded pointer to a heap
+// object where the way of encoding depends on the type of the slot.
+// They are recorded as a pair (SlotType, slot address).
+// We assume that zero-page is never mapped this allows us to distinguish
+// untyped slots from typed slots during iteration by a simple comparison:
+// if element of slots buffer is less than NUMBER_OF_SLOT_TYPES then it
+// is the first element of typed slot's pair.
+class SlotsBuffer {
+ public:
+ typedef Object** ObjectSlot;
+
+ explicit SlotsBuffer(SlotsBuffer* next_buffer)
+ : idx_(0), chain_length_(1), next_(next_buffer) {
+ if (next_ != NULL) {
+ chain_length_ = next_->chain_length_ + 1;
+ }
+ }
+
+ ~SlotsBuffer() {}
+
+ void Add(ObjectSlot slot) {
+ DCHECK(0 <= idx_ && idx_ < kNumberOfElements);
+ slots_[idx_++] = slot;
+ }
+
+ enum SlotType {
+ EMBEDDED_OBJECT_SLOT,
+ RELOCATED_CODE_OBJECT,
+ CODE_TARGET_SLOT,
+ CODE_ENTRY_SLOT,
+ DEBUG_TARGET_SLOT,
+ JS_RETURN_SLOT,
+ NUMBER_OF_SLOT_TYPES
+ };
+
+ static const char* SlotTypeToString(SlotType type) {
+ switch (type) {
+ case EMBEDDED_OBJECT_SLOT:
+ return "EMBEDDED_OBJECT_SLOT";
+ case RELOCATED_CODE_OBJECT:
+ return "RELOCATED_CODE_OBJECT";
+ case CODE_TARGET_SLOT:
+ return "CODE_TARGET_SLOT";
+ case CODE_ENTRY_SLOT:
+ return "CODE_ENTRY_SLOT";
+ case DEBUG_TARGET_SLOT:
+ return "DEBUG_TARGET_SLOT";
+ case JS_RETURN_SLOT:
+ return "JS_RETURN_SLOT";
+ case NUMBER_OF_SLOT_TYPES:
+ return "NUMBER_OF_SLOT_TYPES";
+ }
+ return "UNKNOWN SlotType";
+ }
+
+ void UpdateSlots(Heap* heap);
+
+ void UpdateSlotsWithFilter(Heap* heap);
+
+ SlotsBuffer* next() { return next_; }
+
+ static int SizeOfChain(SlotsBuffer* buffer) {
+ if (buffer == NULL) return 0;
+ return static_cast<int>(buffer->idx_ +
+ (buffer->chain_length_ - 1) * kNumberOfElements);
+ }
+
+ inline bool IsFull() { return idx_ == kNumberOfElements; }
+
+ inline bool HasSpaceForTypedSlot() { return idx_ < kNumberOfElements - 1; }
+
+ static void UpdateSlotsRecordedIn(Heap* heap, SlotsBuffer* buffer,
+ bool code_slots_filtering_required) {
+ while (buffer != NULL) {
+ if (code_slots_filtering_required) {
+ buffer->UpdateSlotsWithFilter(heap);
+ } else {
+ buffer->UpdateSlots(heap);
+ }
+ buffer = buffer->next();
+ }
+ }
+
+ enum AdditionMode { FAIL_ON_OVERFLOW, IGNORE_OVERFLOW };
+
+ static bool ChainLengthThresholdReached(SlotsBuffer* buffer) {
+ return buffer != NULL && buffer->chain_length_ >= kChainLengthThreshold;
+ }
+
+ INLINE(static bool AddTo(SlotsBufferAllocator* allocator,
+ SlotsBuffer** buffer_address, ObjectSlot slot,
+ AdditionMode mode)) {
+ SlotsBuffer* buffer = *buffer_address;
+ if (buffer == NULL || buffer->IsFull()) {
+ if (mode == FAIL_ON_OVERFLOW && ChainLengthThresholdReached(buffer)) {
+ allocator->DeallocateChain(buffer_address);
+ return false;
+ }
+ buffer = allocator->AllocateBuffer(buffer);
+ *buffer_address = buffer;
+ }
+ buffer->Add(slot);
+ return true;
+ }
+
+ static bool IsTypedSlot(ObjectSlot slot);
+
+ static bool AddTo(SlotsBufferAllocator* allocator,
+ SlotsBuffer** buffer_address, SlotType type, Address addr,
+ AdditionMode mode);
+
+ static const int kNumberOfElements = 1021;
+
+ private:
+ static const int kChainLengthThreshold = 15;
+
+ intptr_t idx_;
+ intptr_t chain_length_;
+ SlotsBuffer* next_;
+ ObjectSlot slots_[kNumberOfElements];
+};
+
+
+// CodeFlusher collects candidates for code flushing during marking and
+// processes those candidates after marking has completed in order to
+// reset those functions referencing code objects that would otherwise
+// be unreachable. Code objects can be referenced in three ways:
+// - SharedFunctionInfo references unoptimized code.
+// - JSFunction references either unoptimized or optimized code.
+// - OptimizedCodeMap references optimized code.
+// We are not allowed to flush unoptimized code for functions that got
+// optimized or inlined into optimized code, because we might bailout
+// into the unoptimized code again during deoptimization.
+class CodeFlusher {
+ public:
+ explicit CodeFlusher(Isolate* isolate)
+ : isolate_(isolate),
+ jsfunction_candidates_head_(NULL),
+ shared_function_info_candidates_head_(NULL),
+ optimized_code_map_holder_head_(NULL) {}
+
+ void AddCandidate(SharedFunctionInfo* shared_info) {
+ if (GetNextCandidate(shared_info) == NULL) {
+ SetNextCandidate(shared_info, shared_function_info_candidates_head_);
+ shared_function_info_candidates_head_ = shared_info;
+ }
+ }
+
+ void AddCandidate(JSFunction* function) {
+ DCHECK(function->code() == function->shared()->code());
+ if (GetNextCandidate(function)->IsUndefined()) {
+ SetNextCandidate(function, jsfunction_candidates_head_);
+ jsfunction_candidates_head_ = function;
+ }
+ }
+
+ void AddOptimizedCodeMap(SharedFunctionInfo* code_map_holder) {
+ if (GetNextCodeMap(code_map_holder)->IsUndefined()) {
+ SetNextCodeMap(code_map_holder, optimized_code_map_holder_head_);
+ optimized_code_map_holder_head_ = code_map_holder;
+ }
+ }
+
+ void EvictOptimizedCodeMap(SharedFunctionInfo* code_map_holder);
+ void EvictCandidate(SharedFunctionInfo* shared_info);
+ void EvictCandidate(JSFunction* function);
+
+ void ProcessCandidates() {
+ ProcessOptimizedCodeMaps();
+ ProcessSharedFunctionInfoCandidates();
+ ProcessJSFunctionCandidates();
+ }
+
+ void EvictAllCandidates() {
+ EvictOptimizedCodeMaps();
+ EvictJSFunctionCandidates();
+ EvictSharedFunctionInfoCandidates();
+ }
+
+ void IteratePointersToFromSpace(ObjectVisitor* v);
+
+ private:
+ void ProcessOptimizedCodeMaps();
+ void ProcessJSFunctionCandidates();
+ void ProcessSharedFunctionInfoCandidates();
+ void EvictOptimizedCodeMaps();
+ void EvictJSFunctionCandidates();
+ void EvictSharedFunctionInfoCandidates();
+
+ static JSFunction** GetNextCandidateSlot(JSFunction* candidate) {
+ return reinterpret_cast<JSFunction**>(
+ HeapObject::RawField(candidate, JSFunction::kNextFunctionLinkOffset));
+ }
+
+ static JSFunction* GetNextCandidate(JSFunction* candidate) {
+ Object* next_candidate = candidate->next_function_link();
+ return reinterpret_cast<JSFunction*>(next_candidate);
+ }
+
+ static void SetNextCandidate(JSFunction* candidate,
+ JSFunction* next_candidate) {
+ candidate->set_next_function_link(next_candidate);
+ }
+
+ static void ClearNextCandidate(JSFunction* candidate, Object* undefined) {
+ DCHECK(undefined->IsUndefined());
+ candidate->set_next_function_link(undefined, SKIP_WRITE_BARRIER);
+ }
+
+ static SharedFunctionInfo* GetNextCandidate(SharedFunctionInfo* candidate) {
+ Object* next_candidate = candidate->code()->gc_metadata();
+ return reinterpret_cast<SharedFunctionInfo*>(next_candidate);
+ }
+
+ static void SetNextCandidate(SharedFunctionInfo* candidate,
+ SharedFunctionInfo* next_candidate) {
+ candidate->code()->set_gc_metadata(next_candidate);
+ }
+
+ static void ClearNextCandidate(SharedFunctionInfo* candidate) {
+ candidate->code()->set_gc_metadata(NULL, SKIP_WRITE_BARRIER);
+ }
+
+ static SharedFunctionInfo* GetNextCodeMap(SharedFunctionInfo* holder) {
+ FixedArray* code_map = FixedArray::cast(holder->optimized_code_map());
+ Object* next_map = code_map->get(SharedFunctionInfo::kNextMapIndex);
+ return reinterpret_cast<SharedFunctionInfo*>(next_map);
+ }
+
+ static void SetNextCodeMap(SharedFunctionInfo* holder,
+ SharedFunctionInfo* next_holder) {
+ FixedArray* code_map = FixedArray::cast(holder->optimized_code_map());
+ code_map->set(SharedFunctionInfo::kNextMapIndex, next_holder);
+ }
+
+ static void ClearNextCodeMap(SharedFunctionInfo* holder) {
+ FixedArray* code_map = FixedArray::cast(holder->optimized_code_map());
+ code_map->set_undefined(SharedFunctionInfo::kNextMapIndex);
+ }
+
+ Isolate* isolate_;
+ JSFunction* jsfunction_candidates_head_;
+ SharedFunctionInfo* shared_function_info_candidates_head_;
+ SharedFunctionInfo* optimized_code_map_holder_head_;
+
+ DISALLOW_COPY_AND_ASSIGN(CodeFlusher);
+};
+
+
+// Defined in isolate.h.
+class ThreadLocalTop;
+
+
+// -------------------------------------------------------------------------
+// Mark-Compact collector
+class MarkCompactCollector {
+ public:
+ // Set the global flags, it must be called before Prepare to take effect.
+ inline void SetFlags(int flags);
+
+ static void Initialize();
+
+ void SetUp();
+
+ void TearDown();
+
+ void CollectEvacuationCandidates(PagedSpace* space);
+
+ void AddEvacuationCandidate(Page* p);
+
+ // Prepares for GC by resetting relocation info in old and map spaces and
+ // choosing spaces to compact.
+ void Prepare();
+
+ // Performs a global garbage collection.
+ void CollectGarbage();
+
+ enum CompactionMode { INCREMENTAL_COMPACTION, NON_INCREMENTAL_COMPACTION };
+
+ bool StartCompaction(CompactionMode mode);
+
+ void AbortCompaction();
+
+#ifdef DEBUG
+ // Checks whether performing mark-compact collection.
+ bool in_use() { return state_ > PREPARE_GC; }
+ bool are_map_pointers_encoded() { return state_ == UPDATE_POINTERS; }
+#endif
+
+ // Determine type of object and emit deletion log event.
+ static void ReportDeleteIfNeeded(HeapObject* obj, Isolate* isolate);
+
+ // Distinguishable invalid map encodings (for single word and multiple words)
+ // that indicate free regions.
+ static const uint32_t kSingleFreeEncoding = 0;
+ static const uint32_t kMultiFreeEncoding = 1;
+
+ static inline bool IsMarked(Object* obj);
+
+ inline Heap* heap() const { return heap_; }
+ inline Isolate* isolate() const;
+
+ CodeFlusher* code_flusher() { return code_flusher_; }
+ inline bool is_code_flushing_enabled() const { return code_flusher_ != NULL; }
+ void EnableCodeFlushing(bool enable);
+
+ enum SweeperType {
+ PARALLEL_SWEEPING,
+ CONCURRENT_SWEEPING,
+ SEQUENTIAL_SWEEPING
+ };
+
+ enum SweepingParallelism { SWEEP_ON_MAIN_THREAD, SWEEP_IN_PARALLEL };
+
+#ifdef VERIFY_HEAP
+ void VerifyMarkbitsAreClean();
+ static void VerifyMarkbitsAreClean(PagedSpace* space);
+ static void VerifyMarkbitsAreClean(NewSpace* space);
+ void VerifyWeakEmbeddedObjectsInCode();
+ void VerifyOmittedMapChecks();
+#endif
+
+ INLINE(static bool ShouldSkipEvacuationSlotRecording(Object** anchor)) {
+ return Page::FromAddress(reinterpret_cast<Address>(anchor))
+ ->ShouldSkipEvacuationSlotRecording();
+ }
+
+ INLINE(static bool ShouldSkipEvacuationSlotRecording(Object* host)) {
+ return Page::FromAddress(reinterpret_cast<Address>(host))
+ ->ShouldSkipEvacuationSlotRecording();
+ }
+
+ INLINE(static bool IsOnEvacuationCandidate(Object* obj)) {
+ return Page::FromAddress(reinterpret_cast<Address>(obj))
+ ->IsEvacuationCandidate();
+ }
+
+ INLINE(void EvictEvacuationCandidate(Page* page)) {
+ if (FLAG_trace_fragmentation) {
+ PrintF("Page %p is too popular. Disabling evacuation.\n",
+ reinterpret_cast<void*>(page));
+ }
+
+ // TODO(gc) If all evacuation candidates are too popular we
+ // should stop slots recording entirely.
+ page->ClearEvacuationCandidate();
+
+ // We were not collecting slots on this page that point
+ // to other evacuation candidates thus we have to
+ // rescan the page after evacuation to discover and update all
+ // pointers to evacuated objects.
+ if (page->owner()->identity() == OLD_DATA_SPACE) {
+ evacuation_candidates_.RemoveElement(page);
+ } else {
+ page->SetFlag(Page::RESCAN_ON_EVACUATION);
+ }
+ }
+
+ void RecordRelocSlot(RelocInfo* rinfo, Object* target);
+ void RecordCodeEntrySlot(Address slot, Code* target);
+ void RecordCodeTargetPatch(Address pc, Code* target);
+
+ INLINE(void RecordSlot(
+ Object** anchor_slot, Object** slot, Object* object,
+ SlotsBuffer::AdditionMode mode = SlotsBuffer::FAIL_ON_OVERFLOW));
+
+ void MigrateObject(HeapObject* dst, HeapObject* src, int size,
+ AllocationSpace to_old_space);
+
+ bool TryPromoteObject(HeapObject* object, int object_size);
+
+ void InvalidateCode(Code* code);
+
+ void ClearMarkbits();
+
+ bool abort_incremental_marking() const { return abort_incremental_marking_; }
+
+ bool is_compacting() const { return compacting_; }
+
+ MarkingParity marking_parity() { return marking_parity_; }
+
+ // Concurrent and parallel sweeping support. If required_freed_bytes was set
+ // to a value larger than 0, then sweeping returns after a block of at least
+ // required_freed_bytes was freed. If required_freed_bytes was set to zero
+ // then the whole given space is swept. It returns the size of the maximum
+ // continuous freed memory chunk.
+ int SweepInParallel(PagedSpace* space, int required_freed_bytes);
+
+ // Sweeps a given page concurrently to the sweeper threads. It returns the
+ // size of the maximum continuous freed memory chunk.
+ int SweepInParallel(Page* page, PagedSpace* space);
+
+ void EnsureSweepingCompleted();
+
+ // If sweeper threads are not active this method will return true. If
+ // this is a latency issue we should be smarter here. Otherwise, it will
+ // return true if the sweeper threads are done processing the pages.
+ bool IsSweepingCompleted();
+
+ void RefillFreeList(PagedSpace* space);
+
+ bool AreSweeperThreadsActivated();
+
+ // Checks if sweeping is in progress right now on any space.
+ bool sweeping_in_progress() { return sweeping_in_progress_; }
+
+ void set_sequential_sweeping(bool sequential_sweeping) {
+ sequential_sweeping_ = sequential_sweeping;
+ }
+
+ bool sequential_sweeping() const { return sequential_sweeping_; }
+
+ // Mark the global table which maps weak objects to dependent code without
+ // marking its contents.
+ void MarkWeakObjectToCodeTable();
+
+ // Special case for processing weak references in a full collection. We need
+ // to artificially keep AllocationSites alive for a time.
+ void MarkAllocationSite(AllocationSite* site);
+
+ private:
+ class SweeperTask;
+
+ explicit MarkCompactCollector(Heap* heap);
+ ~MarkCompactCollector();
+
+ bool MarkInvalidatedCode();
+ bool WillBeDeoptimized(Code* code);
+ void RemoveDeadInvalidatedCode();
+ void ProcessInvalidatedCode(ObjectVisitor* visitor);
+
+ void StartSweeperThreads();
+
+#ifdef DEBUG
+ enum CollectorState {
+ IDLE,
+ PREPARE_GC,
+ MARK_LIVE_OBJECTS,
+ SWEEP_SPACES,
+ ENCODE_FORWARDING_ADDRESSES,
+ UPDATE_POINTERS,
+ RELOCATE_OBJECTS
+ };
+
+ // The current stage of the collector.
+ CollectorState state_;
+#endif
+
+ bool reduce_memory_footprint_;
+
+ bool abort_incremental_marking_;
+
+ MarkingParity marking_parity_;
+
+ // True if we are collecting slots to perform evacuation from evacuation
+ // candidates.
+ bool compacting_;
+
+ bool was_marked_incrementally_;
+
+ // True if concurrent or parallel sweeping is currently in progress.
+ bool sweeping_in_progress_;
+
+ base::Semaphore pending_sweeper_jobs_semaphore_;
+
+ bool sequential_sweeping_;
+
+ SlotsBufferAllocator slots_buffer_allocator_;
+
+ SlotsBuffer* migration_slots_buffer_;
+
+ // Finishes GC, performs heap verification if enabled.
+ void Finish();
+
+ // -----------------------------------------------------------------------
+ // Phase 1: Marking live objects.
+ //
+ // Before: The heap has been prepared for garbage collection by
+ // MarkCompactCollector::Prepare() and is otherwise in its
+ // normal state.
+ //
+ // After: Live objects are marked and non-live objects are unmarked.
+
+ friend class RootMarkingVisitor;
+ friend class MarkingVisitor;
+ friend class MarkCompactMarkingVisitor;
+ friend class CodeMarkingVisitor;
+ friend class SharedFunctionInfoMarkingVisitor;
+
+ // Mark code objects that are active on the stack to prevent them
+ // from being flushed.
+ void PrepareThreadForCodeFlushing(Isolate* isolate, ThreadLocalTop* top);
+
+ void PrepareForCodeFlushing();
+
+ // Marking operations for objects reachable from roots.
+ void MarkLiveObjects();
+
+ void AfterMarking();
+
+ // Marks the object black and pushes it on the marking stack.
+ // This is for non-incremental marking only.
+ INLINE(void MarkObject(HeapObject* obj, MarkBit mark_bit));
+
+ // Marks the object black assuming that it is not yet marked.
+ // This is for non-incremental marking only.
+ INLINE(void SetMark(HeapObject* obj, MarkBit mark_bit));
+
+ // Mark the heap roots and all objects reachable from them.
+ void MarkRoots(RootMarkingVisitor* visitor);
+
+ // Mark the string table specially. References to internalized strings from
+ // the string table are weak.
+ void MarkStringTable(RootMarkingVisitor* visitor);
+
+ // Mark objects in implicit references groups if their parent object
+ // is marked.
+ void MarkImplicitRefGroups();
+
+ // Mark objects reachable (transitively) from objects in the marking stack
+ // or overflowed in the heap.
+ void ProcessMarkingDeque();
+
+ // Mark objects reachable (transitively) from objects in the marking stack
+ // or overflowed in the heap. This respects references only considered in
+ // the final atomic marking pause including the following:
+ // - Processing of objects reachable through Harmony WeakMaps.
+ // - Objects reachable due to host application logic like object groups
+ // or implicit references' groups.
+ void ProcessEphemeralMarking(ObjectVisitor* visitor);
+
+ // If the call-site of the top optimized code was not prepared for
+ // deoptimization, then treat the maps in the code as strong pointers,
+ // otherwise a map can die and deoptimize the code.
+ void ProcessTopOptimizedFrame(ObjectVisitor* visitor);
+
+ // Mark objects reachable (transitively) from objects in the marking
+ // stack. This function empties the marking stack, but may leave
+ // overflowed objects in the heap, in which case the marking stack's
+ // overflow flag will be set.
+ void EmptyMarkingDeque();
+
+ // Refill the marking stack with overflowed objects from the heap. This
+ // function either leaves the marking stack full or clears the overflow
+ // flag on the marking stack.
+ void RefillMarkingDeque();
+
+ // After reachable maps have been marked process per context object
+ // literal map caches removing unmarked entries.
+ void ProcessMapCaches();
+
+ // Callback function for telling whether the object *p is an unmarked
+ // heap object.
+ static bool IsUnmarkedHeapObject(Object** p);
+ static bool IsUnmarkedHeapObjectWithHeap(Heap* heap, Object** p);
+
+ // Map transitions from a live map to a dead map must be killed.
+ // We replace them with a null descriptor, with the same key.
+ void ClearNonLiveReferences();
+ void ClearNonLivePrototypeTransitions(Map* map);
+ void ClearNonLiveMapTransitions(Map* map, MarkBit map_mark);
+ void ClearMapTransitions(Map* map);
+ bool ClearMapBackPointer(Map* map);
+ void TrimDescriptorArray(Map* map, DescriptorArray* descriptors,
+ int number_of_own_descriptors);
+ void TrimEnumCache(Map* map, DescriptorArray* descriptors);
+
+ void ClearDependentCode(DependentCode* dependent_code);
+ void ClearDependentICList(Object* head);
+ void ClearNonLiveDependentCode(DependentCode* dependent_code);
+ int ClearNonLiveDependentCodeInGroup(DependentCode* dependent_code, int group,
+ int start, int end, int new_start);
+
+ // Mark all values associated with reachable keys in weak collections
+ // encountered so far. This might push new object or even new weak maps onto
+ // the marking stack.
+ void ProcessWeakCollections();
+
+ // After all reachable objects have been marked those weak map entries
+ // with an unreachable key are removed from all encountered weak maps.
+ // The linked list of all encountered weak maps is destroyed.
+ void ClearWeakCollections();
+
+ // We have to remove all encountered weak maps from the list of weak
+ // collections when incremental marking is aborted.
+ void AbortWeakCollections();
+
+ // -----------------------------------------------------------------------
+ // Phase 2: Sweeping to clear mark bits and free non-live objects for
+ // a non-compacting collection.
+ //
+ // Before: Live objects are marked and non-live objects are unmarked.
+ //
+ // After: Live objects are unmarked, non-live regions have been added to
+ // their space's free list. Active eden semispace is compacted by
+ // evacuation.
+ //
+
+ // If we are not compacting the heap, we simply sweep the spaces except
+ // for the large object space, clearing mark bits and adding unmarked
+ // regions to each space's free list.
+ void SweepSpaces();
+
+ int DiscoverAndEvacuateBlackObjectsOnPage(NewSpace* new_space,
+ NewSpacePage* p);
+
+ void EvacuateNewSpace();
+
+ void EvacuateLiveObjectsFromPage(Page* p);
+
+ void EvacuatePages();
+
+ void EvacuateNewSpaceAndCandidates();
+
+ void ReleaseEvacuationCandidates();
+
+ // Moves the pages of the evacuation_candidates_ list to the end of their
+ // corresponding space pages list.
+ void MoveEvacuationCandidatesToEndOfPagesList();
+
+ void SweepSpace(PagedSpace* space, SweeperType sweeper);
+
+ // Finalizes the parallel sweeping phase. Marks all the pages that were
+ // swept in parallel.
+ void ParallelSweepSpacesComplete();
+
+ void ParallelSweepSpaceComplete(PagedSpace* space);
+
+ // Updates store buffer and slot buffer for a pointer in a migrating object.
+ void RecordMigratedSlot(Object* value, Address slot);
+
+#ifdef DEBUG
+ friend class MarkObjectVisitor;
+ static void VisitObject(HeapObject* obj);
+
+ friend class UnmarkObjectVisitor;
+ static void UnmarkObject(HeapObject* obj);
+#endif
+
+ Heap* heap_;
+ MarkingDeque marking_deque_;
+ CodeFlusher* code_flusher_;
+ bool have_code_to_deoptimize_;
+
+ List<Page*> evacuation_candidates_;
+ List<Code*> invalidated_code_;
+
+ SmartPointer<FreeList> free_list_old_data_space_;
+ SmartPointer<FreeList> free_list_old_pointer_space_;
+
+ friend class Heap;
+};
+
+
+class MarkBitCellIterator BASE_EMBEDDED {
+ public:
+ explicit MarkBitCellIterator(MemoryChunk* chunk) : chunk_(chunk) {
+ last_cell_index_ = Bitmap::IndexToCell(Bitmap::CellAlignIndex(
+ chunk_->AddressToMarkbitIndex(chunk_->area_end())));
+ cell_base_ = chunk_->area_start();
+ cell_index_ = Bitmap::IndexToCell(
+ Bitmap::CellAlignIndex(chunk_->AddressToMarkbitIndex(cell_base_)));
+ cells_ = chunk_->markbits()->cells();
+ }
+
+ inline bool Done() { return cell_index_ == last_cell_index_; }
+
+ inline bool HasNext() { return cell_index_ < last_cell_index_ - 1; }
+
+ inline MarkBit::CellType* CurrentCell() {
+ DCHECK(cell_index_ == Bitmap::IndexToCell(Bitmap::CellAlignIndex(
+ chunk_->AddressToMarkbitIndex(cell_base_))));
+ return &cells_[cell_index_];
+ }
+
+ inline Address CurrentCellBase() {
+ DCHECK(cell_index_ == Bitmap::IndexToCell(Bitmap::CellAlignIndex(
+ chunk_->AddressToMarkbitIndex(cell_base_))));
+ return cell_base_;
+ }
+
+ inline void Advance() {
+ cell_index_++;
+ cell_base_ += 32 * kPointerSize;
+ }
+
+ private:
+ MemoryChunk* chunk_;
+ MarkBit::CellType* cells_;
+ unsigned int last_cell_index_;
+ unsigned int cell_index_;
+ Address cell_base_;
+};
+
+
+class SequentialSweepingScope BASE_EMBEDDED {
+ public:
+ explicit SequentialSweepingScope(MarkCompactCollector* collector)
+ : collector_(collector) {
+ collector_->set_sequential_sweeping(true);
+ }
+
+ ~SequentialSweepingScope() { collector_->set_sequential_sweeping(false); }
+
+ private:
+ MarkCompactCollector* collector_;
+};
+
+
+const char* AllocationSpaceName(AllocationSpace space);
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_MARK_COMPACT_H_
diff --git a/src/heap/objects-visiting-inl.h b/src/heap/objects-visiting-inl.h
new file mode 100644
index 0000000..d220118
--- /dev/null
+++ b/src/heap/objects-visiting-inl.h
@@ -0,0 +1,934 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_OBJECTS_VISITING_INL_H_
+#define V8_OBJECTS_VISITING_INL_H_
+
+
+namespace v8 {
+namespace internal {
+
+template <typename StaticVisitor>
+void StaticNewSpaceVisitor<StaticVisitor>::Initialize() {
+ table_.Register(
+ kVisitShortcutCandidate,
+ &FixedBodyVisitor<StaticVisitor, ConsString::BodyDescriptor, int>::Visit);
+
+ table_.Register(
+ kVisitConsString,
+ &FixedBodyVisitor<StaticVisitor, ConsString::BodyDescriptor, int>::Visit);
+
+ table_.Register(kVisitSlicedString,
+ &FixedBodyVisitor<StaticVisitor, SlicedString::BodyDescriptor,
+ int>::Visit);
+
+ table_.Register(
+ kVisitSymbol,
+ &FixedBodyVisitor<StaticVisitor, Symbol::BodyDescriptor, int>::Visit);
+
+ table_.Register(kVisitFixedArray,
+ &FlexibleBodyVisitor<StaticVisitor,
+ FixedArray::BodyDescriptor, int>::Visit);
+
+ table_.Register(kVisitFixedDoubleArray, &VisitFixedDoubleArray);
+ table_.Register(kVisitFixedTypedArray, &VisitFixedTypedArray);
+ table_.Register(kVisitFixedFloat64Array, &VisitFixedTypedArray);
+
+ table_.Register(
+ kVisitNativeContext,
+ &FixedBodyVisitor<StaticVisitor, Context::ScavengeBodyDescriptor,
+ int>::Visit);
+
+ table_.Register(kVisitByteArray, &VisitByteArray);
+
+ table_.Register(
+ kVisitSharedFunctionInfo,
+ &FixedBodyVisitor<StaticVisitor, SharedFunctionInfo::BodyDescriptor,
+ int>::Visit);
+
+ table_.Register(kVisitSeqOneByteString, &VisitSeqOneByteString);
+
+ table_.Register(kVisitSeqTwoByteString, &VisitSeqTwoByteString);
+
+ table_.Register(kVisitJSFunction, &VisitJSFunction);
+
+ table_.Register(kVisitJSArrayBuffer, &VisitJSArrayBuffer);
+
+ table_.Register(kVisitJSTypedArray, &VisitJSTypedArray);
+
+ table_.Register(kVisitJSDataView, &VisitJSDataView);
+
+ table_.Register(kVisitFreeSpace, &VisitFreeSpace);
+
+ table_.Register(kVisitJSWeakCollection, &JSObjectVisitor::Visit);
+
+ table_.Register(kVisitJSRegExp, &JSObjectVisitor::Visit);
+
+ table_.template RegisterSpecializations<DataObjectVisitor, kVisitDataObject,
+ kVisitDataObjectGeneric>();
+
+ table_.template RegisterSpecializations<JSObjectVisitor, kVisitJSObject,
+ kVisitJSObjectGeneric>();
+ table_.template RegisterSpecializations<StructVisitor, kVisitStruct,
+ kVisitStructGeneric>();
+}
+
+
+template <typename StaticVisitor>
+int StaticNewSpaceVisitor<StaticVisitor>::VisitJSArrayBuffer(
+ Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+
+ STATIC_ASSERT(JSArrayBuffer::kWeakFirstViewOffset ==
+ JSArrayBuffer::kWeakNextOffset + kPointerSize);
+ VisitPointers(heap, HeapObject::RawField(
+ object, JSArrayBuffer::BodyDescriptor::kStartOffset),
+ HeapObject::RawField(object, JSArrayBuffer::kWeakNextOffset));
+ VisitPointers(
+ heap, HeapObject::RawField(
+ object, JSArrayBuffer::kWeakNextOffset + 2 * kPointerSize),
+ HeapObject::RawField(object, JSArrayBuffer::kSizeWithInternalFields));
+ return JSArrayBuffer::kSizeWithInternalFields;
+}
+
+
+template <typename StaticVisitor>
+int StaticNewSpaceVisitor<StaticVisitor>::VisitJSTypedArray(
+ Map* map, HeapObject* object) {
+ VisitPointers(
+ map->GetHeap(),
+ HeapObject::RawField(object, JSTypedArray::BodyDescriptor::kStartOffset),
+ HeapObject::RawField(object, JSTypedArray::kWeakNextOffset));
+ VisitPointers(
+ map->GetHeap(), HeapObject::RawField(
+ object, JSTypedArray::kWeakNextOffset + kPointerSize),
+ HeapObject::RawField(object, JSTypedArray::kSizeWithInternalFields));
+ return JSTypedArray::kSizeWithInternalFields;
+}
+
+
+template <typename StaticVisitor>
+int StaticNewSpaceVisitor<StaticVisitor>::VisitJSDataView(Map* map,
+ HeapObject* object) {
+ VisitPointers(
+ map->GetHeap(),
+ HeapObject::RawField(object, JSDataView::BodyDescriptor::kStartOffset),
+ HeapObject::RawField(object, JSDataView::kWeakNextOffset));
+ VisitPointers(
+ map->GetHeap(),
+ HeapObject::RawField(object, JSDataView::kWeakNextOffset + kPointerSize),
+ HeapObject::RawField(object, JSDataView::kSizeWithInternalFields));
+ return JSDataView::kSizeWithInternalFields;
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::Initialize() {
+ table_.Register(kVisitShortcutCandidate,
+ &FixedBodyVisitor<StaticVisitor, ConsString::BodyDescriptor,
+ void>::Visit);
+
+ table_.Register(kVisitConsString,
+ &FixedBodyVisitor<StaticVisitor, ConsString::BodyDescriptor,
+ void>::Visit);
+
+ table_.Register(kVisitSlicedString,
+ &FixedBodyVisitor<StaticVisitor, SlicedString::BodyDescriptor,
+ void>::Visit);
+
+ table_.Register(
+ kVisitSymbol,
+ &FixedBodyVisitor<StaticVisitor, Symbol::BodyDescriptor, void>::Visit);
+
+ table_.Register(kVisitFixedArray, &FixedArrayVisitor::Visit);
+
+ table_.Register(kVisitFixedDoubleArray, &DataObjectVisitor::Visit);
+
+ table_.Register(kVisitFixedTypedArray, &DataObjectVisitor::Visit);
+
+ table_.Register(kVisitFixedFloat64Array, &DataObjectVisitor::Visit);
+
+ table_.Register(kVisitConstantPoolArray, &VisitConstantPoolArray);
+
+ table_.Register(kVisitNativeContext, &VisitNativeContext);
+
+ table_.Register(kVisitAllocationSite, &VisitAllocationSite);
+
+ table_.Register(kVisitByteArray, &DataObjectVisitor::Visit);
+
+ table_.Register(kVisitFreeSpace, &DataObjectVisitor::Visit);
+
+ table_.Register(kVisitSeqOneByteString, &DataObjectVisitor::Visit);
+
+ table_.Register(kVisitSeqTwoByteString, &DataObjectVisitor::Visit);
+
+ table_.Register(kVisitJSWeakCollection, &VisitWeakCollection);
+
+ table_.Register(
+ kVisitOddball,
+ &FixedBodyVisitor<StaticVisitor, Oddball::BodyDescriptor, void>::Visit);
+
+ table_.Register(kVisitMap, &VisitMap);
+
+ table_.Register(kVisitCode, &VisitCode);
+
+ table_.Register(kVisitSharedFunctionInfo, &VisitSharedFunctionInfo);
+
+ table_.Register(kVisitJSFunction, &VisitJSFunction);
+
+ table_.Register(kVisitJSArrayBuffer, &VisitJSArrayBuffer);
+
+ table_.Register(kVisitJSTypedArray, &VisitJSTypedArray);
+
+ table_.Register(kVisitJSDataView, &VisitJSDataView);
+
+ // Registration for kVisitJSRegExp is done by StaticVisitor.
+
+ table_.Register(
+ kVisitCell,
+ &FixedBodyVisitor<StaticVisitor, Cell::BodyDescriptor, void>::Visit);
+
+ table_.Register(kVisitPropertyCell, &VisitPropertyCell);
+
+ table_.template RegisterSpecializations<DataObjectVisitor, kVisitDataObject,
+ kVisitDataObjectGeneric>();
+
+ table_.template RegisterSpecializations<JSObjectVisitor, kVisitJSObject,
+ kVisitJSObjectGeneric>();
+
+ table_.template RegisterSpecializations<StructObjectVisitor, kVisitStruct,
+ kVisitStructGeneric>();
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitCodeEntry(
+ Heap* heap, Address entry_address) {
+ Code* code = Code::cast(Code::GetObjectFromEntryAddress(entry_address));
+ heap->mark_compact_collector()->RecordCodeEntrySlot(entry_address, code);
+ StaticVisitor::MarkObject(heap, code);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitEmbeddedPointer(
+ Heap* heap, RelocInfo* rinfo) {
+ DCHECK(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT);
+ HeapObject* object = HeapObject::cast(rinfo->target_object());
+ heap->mark_compact_collector()->RecordRelocSlot(rinfo, object);
+ // TODO(ulan): It could be better to record slots only for strongly embedded
+ // objects here and record slots for weakly embedded object during clearing
+ // of non-live references in mark-compact.
+ if (!rinfo->host()->IsWeakObject(object)) {
+ StaticVisitor::MarkObject(heap, object);
+ }
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitCell(Heap* heap,
+ RelocInfo* rinfo) {
+ DCHECK(rinfo->rmode() == RelocInfo::CELL);
+ Cell* cell = rinfo->target_cell();
+ // No need to record slots because the cell space is not compacted during GC.
+ if (!rinfo->host()->IsWeakObject(cell)) {
+ StaticVisitor::MarkObject(heap, cell);
+ }
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitDebugTarget(Heap* heap,
+ RelocInfo* rinfo) {
+ DCHECK((RelocInfo::IsJSReturn(rinfo->rmode()) &&
+ rinfo->IsPatchedReturnSequence()) ||
+ (RelocInfo::IsDebugBreakSlot(rinfo->rmode()) &&
+ rinfo->IsPatchedDebugBreakSlotSequence()));
+ Code* target = Code::GetCodeFromTargetAddress(rinfo->call_address());
+ heap->mark_compact_collector()->RecordRelocSlot(rinfo, target);
+ StaticVisitor::MarkObject(heap, target);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitCodeTarget(Heap* heap,
+ RelocInfo* rinfo) {
+ DCHECK(RelocInfo::IsCodeTarget(rinfo->rmode()));
+ Code* target = Code::GetCodeFromTargetAddress(rinfo->target_address());
+ // Monomorphic ICs are preserved when possible, but need to be flushed
+ // when they might be keeping a Context alive, or when the heap is about
+ // to be serialized.
+ if (FLAG_cleanup_code_caches_at_gc && target->is_inline_cache_stub() &&
+ (target->ic_state() == MEGAMORPHIC || target->ic_state() == GENERIC ||
+ target->ic_state() == POLYMORPHIC ||
+ (heap->flush_monomorphic_ics() && !target->is_weak_stub()) ||
+ heap->isolate()->serializer_enabled() ||
+ target->ic_age() != heap->global_ic_age() ||
+ target->is_invalidated_weak_stub())) {
+ ICUtility::Clear(heap->isolate(), rinfo->pc(),
+ rinfo->host()->constant_pool());
+ target = Code::GetCodeFromTargetAddress(rinfo->target_address());
+ }
+ heap->mark_compact_collector()->RecordRelocSlot(rinfo, target);
+ StaticVisitor::MarkObject(heap, target);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitCodeAgeSequence(
+ Heap* heap, RelocInfo* rinfo) {
+ DCHECK(RelocInfo::IsCodeAgeSequence(rinfo->rmode()));
+ Code* target = rinfo->code_age_stub();
+ DCHECK(target != NULL);
+ heap->mark_compact_collector()->RecordRelocSlot(rinfo, target);
+ StaticVisitor::MarkObject(heap, target);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitNativeContext(
+ Map* map, HeapObject* object) {
+ FixedBodyVisitor<StaticVisitor, Context::MarkCompactBodyDescriptor,
+ void>::Visit(map, object);
+
+ MarkCompactCollector* collector = map->GetHeap()->mark_compact_collector();
+ for (int idx = Context::FIRST_WEAK_SLOT; idx < Context::NATIVE_CONTEXT_SLOTS;
+ ++idx) {
+ Object** slot = Context::cast(object)->RawFieldOfElementAt(idx);
+ collector->RecordSlot(slot, slot, *slot);
+ }
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitMap(Map* map,
+ HeapObject* object) {
+ Heap* heap = map->GetHeap();
+ Map* map_object = Map::cast(object);
+
+ // Clears the cache of ICs related to this map.
+ if (FLAG_cleanup_code_caches_at_gc) {
+ map_object->ClearCodeCache(heap);
+ }
+
+ // When map collection is enabled we have to mark through map's transitions
+ // and back pointers in a special way to make these links weak.
+ if (FLAG_collect_maps && map_object->CanTransition()) {
+ MarkMapContents(heap, map_object);
+ } else {
+ StaticVisitor::VisitPointers(
+ heap, HeapObject::RawField(object, Map::kPointerFieldsBeginOffset),
+ HeapObject::RawField(object, Map::kPointerFieldsEndOffset));
+ }
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitPropertyCell(
+ Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+
+ Object** slot =
+ HeapObject::RawField(object, PropertyCell::kDependentCodeOffset);
+ if (FLAG_collect_maps) {
+ // Mark property cell dependent codes array but do not push it onto marking
+ // stack, this will make references from it weak. We will clean dead
+ // codes when we iterate over property cells in ClearNonLiveReferences.
+ HeapObject* obj = HeapObject::cast(*slot);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, obj);
+ StaticVisitor::MarkObjectWithoutPush(heap, obj);
+ } else {
+ StaticVisitor::VisitPointer(heap, slot);
+ }
+
+ StaticVisitor::VisitPointers(
+ heap,
+ HeapObject::RawField(object, PropertyCell::kPointerFieldsBeginOffset),
+ HeapObject::RawField(object, PropertyCell::kPointerFieldsEndOffset));
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitAllocationSite(
+ Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+
+ Object** slot =
+ HeapObject::RawField(object, AllocationSite::kDependentCodeOffset);
+ if (FLAG_collect_maps) {
+ // Mark allocation site dependent codes array but do not push it onto
+ // marking stack, this will make references from it weak. We will clean
+ // dead codes when we iterate over allocation sites in
+ // ClearNonLiveReferences.
+ HeapObject* obj = HeapObject::cast(*slot);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, obj);
+ StaticVisitor::MarkObjectWithoutPush(heap, obj);
+ } else {
+ StaticVisitor::VisitPointer(heap, slot);
+ }
+
+ StaticVisitor::VisitPointers(
+ heap,
+ HeapObject::RawField(object, AllocationSite::kPointerFieldsBeginOffset),
+ HeapObject::RawField(object, AllocationSite::kPointerFieldsEndOffset));
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitWeakCollection(
+ Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+ JSWeakCollection* weak_collection =
+ reinterpret_cast<JSWeakCollection*>(object);
+
+ // Enqueue weak collection in linked list of encountered weak collections.
+ if (weak_collection->next() == heap->undefined_value()) {
+ weak_collection->set_next(heap->encountered_weak_collections());
+ heap->set_encountered_weak_collections(weak_collection);
+ }
+
+ // Skip visiting the backing hash table containing the mappings and the
+ // pointer to the other enqueued weak collections, both are post-processed.
+ StaticVisitor::VisitPointers(
+ heap, HeapObject::RawField(object, JSWeakCollection::kPropertiesOffset),
+ HeapObject::RawField(object, JSWeakCollection::kTableOffset));
+ STATIC_ASSERT(JSWeakCollection::kTableOffset + kPointerSize ==
+ JSWeakCollection::kNextOffset);
+ STATIC_ASSERT(JSWeakCollection::kNextOffset + kPointerSize ==
+ JSWeakCollection::kSize);
+
+ // Partially initialized weak collection is enqueued, but table is ignored.
+ if (!weak_collection->table()->IsHashTable()) return;
+
+ // Mark the backing hash table without pushing it on the marking stack.
+ Object** slot = HeapObject::RawField(object, JSWeakCollection::kTableOffset);
+ HeapObject* obj = HeapObject::cast(*slot);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, obj);
+ StaticVisitor::MarkObjectWithoutPush(heap, obj);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitCode(Map* map,
+ HeapObject* object) {
+ Heap* heap = map->GetHeap();
+ Code* code = Code::cast(object);
+ if (FLAG_age_code && !heap->isolate()->serializer_enabled()) {
+ code->MakeOlder(heap->mark_compact_collector()->marking_parity());
+ }
+ code->CodeIterateBody<StaticVisitor>(heap);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitSharedFunctionInfo(
+ Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+ SharedFunctionInfo* shared = SharedFunctionInfo::cast(object);
+ if (shared->ic_age() != heap->global_ic_age()) {
+ shared->ResetForNewContext(heap->global_ic_age());
+ }
+ if (FLAG_cleanup_code_caches_at_gc) {
+ shared->ClearTypeFeedbackInfo();
+ }
+ if (FLAG_cache_optimized_code && FLAG_flush_optimized_code_cache &&
+ !shared->optimized_code_map()->IsSmi()) {
+ // Always flush the optimized code map if requested by flag.
+ shared->ClearOptimizedCodeMap();
+ }
+ MarkCompactCollector* collector = heap->mark_compact_collector();
+ if (collector->is_code_flushing_enabled()) {
+ if (FLAG_cache_optimized_code && !shared->optimized_code_map()->IsSmi()) {
+ // Add the shared function info holding an optimized code map to
+ // the code flusher for processing of code maps after marking.
+ collector->code_flusher()->AddOptimizedCodeMap(shared);
+ // Treat all references within the code map weakly by marking the
+ // code map itself but not pushing it onto the marking deque.
+ FixedArray* code_map = FixedArray::cast(shared->optimized_code_map());
+ StaticVisitor::MarkObjectWithoutPush(heap, code_map);
+ }
+ if (IsFlushable(heap, shared)) {
+ // This function's code looks flushable. But we have to postpone
+ // the decision until we see all functions that point to the same
+ // SharedFunctionInfo because some of them might be optimized.
+ // That would also make the non-optimized version of the code
+ // non-flushable, because it is required for bailing out from
+ // optimized code.
+ collector->code_flusher()->AddCandidate(shared);
+ // Treat the reference to the code object weakly.
+ VisitSharedFunctionInfoWeakCode(heap, object);
+ return;
+ }
+ } else {
+ if (FLAG_cache_optimized_code && !shared->optimized_code_map()->IsSmi()) {
+ // Flush optimized code map on major GCs without code flushing,
+ // needed because cached code doesn't contain breakpoints.
+ shared->ClearOptimizedCodeMap();
+ }
+ }
+ VisitSharedFunctionInfoStrongCode(heap, object);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitConstantPoolArray(
+ Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+ ConstantPoolArray* array = ConstantPoolArray::cast(object);
+ ConstantPoolArray::Iterator code_iter(array, ConstantPoolArray::CODE_PTR);
+ while (!code_iter.is_finished()) {
+ Address code_entry = reinterpret_cast<Address>(
+ array->RawFieldOfElementAt(code_iter.next_index()));
+ StaticVisitor::VisitCodeEntry(heap, code_entry);
+ }
+
+ ConstantPoolArray::Iterator heap_iter(array, ConstantPoolArray::HEAP_PTR);
+ while (!heap_iter.is_finished()) {
+ Object** slot = array->RawFieldOfElementAt(heap_iter.next_index());
+ HeapObject* object = HeapObject::cast(*slot);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, object);
+ bool is_weak_object =
+ (array->get_weak_object_state() ==
+ ConstantPoolArray::WEAK_OBJECTS_IN_OPTIMIZED_CODE &&
+ Code::IsWeakObjectInOptimizedCode(object)) ||
+ (array->get_weak_object_state() ==
+ ConstantPoolArray::WEAK_OBJECTS_IN_IC &&
+ Code::IsWeakObjectInIC(object));
+ if (!is_weak_object) {
+ StaticVisitor::MarkObject(heap, object);
+ }
+ }
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitJSFunction(Map* map,
+ HeapObject* object) {
+ Heap* heap = map->GetHeap();
+ JSFunction* function = JSFunction::cast(object);
+ MarkCompactCollector* collector = heap->mark_compact_collector();
+ if (collector->is_code_flushing_enabled()) {
+ if (IsFlushable(heap, function)) {
+ // This function's code looks flushable. But we have to postpone
+ // the decision until we see all functions that point to the same
+ // SharedFunctionInfo because some of them might be optimized.
+ // That would also make the non-optimized version of the code
+ // non-flushable, because it is required for bailing out from
+ // optimized code.
+ collector->code_flusher()->AddCandidate(function);
+ // Visit shared function info immediately to avoid double checking
+ // of its flushability later. This is just an optimization because
+ // the shared function info would eventually be visited.
+ SharedFunctionInfo* shared = function->shared();
+ if (StaticVisitor::MarkObjectWithoutPush(heap, shared)) {
+ StaticVisitor::MarkObject(heap, shared->map());
+ VisitSharedFunctionInfoWeakCode(heap, shared);
+ }
+ // Treat the reference to the code object weakly.
+ VisitJSFunctionWeakCode(heap, object);
+ return;
+ } else {
+ // Visit all unoptimized code objects to prevent flushing them.
+ StaticVisitor::MarkObject(heap, function->shared()->code());
+ if (function->code()->kind() == Code::OPTIMIZED_FUNCTION) {
+ MarkInlinedFunctionsCode(heap, function->code());
+ }
+ }
+ }
+ VisitJSFunctionStrongCode(heap, object);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitJSRegExp(Map* map,
+ HeapObject* object) {
+ int last_property_offset =
+ JSRegExp::kSize + kPointerSize * map->inobject_properties();
+ StaticVisitor::VisitPointers(
+ map->GetHeap(), HeapObject::RawField(object, JSRegExp::kPropertiesOffset),
+ HeapObject::RawField(object, last_property_offset));
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitJSArrayBuffer(
+ Map* map, HeapObject* object) {
+ Heap* heap = map->GetHeap();
+
+ STATIC_ASSERT(JSArrayBuffer::kWeakFirstViewOffset ==
+ JSArrayBuffer::kWeakNextOffset + kPointerSize);
+ StaticVisitor::VisitPointers(
+ heap,
+ HeapObject::RawField(object, JSArrayBuffer::BodyDescriptor::kStartOffset),
+ HeapObject::RawField(object, JSArrayBuffer::kWeakNextOffset));
+ StaticVisitor::VisitPointers(
+ heap, HeapObject::RawField(
+ object, JSArrayBuffer::kWeakNextOffset + 2 * kPointerSize),
+ HeapObject::RawField(object, JSArrayBuffer::kSizeWithInternalFields));
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitJSTypedArray(
+ Map* map, HeapObject* object) {
+ StaticVisitor::VisitPointers(
+ map->GetHeap(),
+ HeapObject::RawField(object, JSTypedArray::BodyDescriptor::kStartOffset),
+ HeapObject::RawField(object, JSTypedArray::kWeakNextOffset));
+ StaticVisitor::VisitPointers(
+ map->GetHeap(), HeapObject::RawField(
+ object, JSTypedArray::kWeakNextOffset + kPointerSize),
+ HeapObject::RawField(object, JSTypedArray::kSizeWithInternalFields));
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitJSDataView(Map* map,
+ HeapObject* object) {
+ StaticVisitor::VisitPointers(
+ map->GetHeap(),
+ HeapObject::RawField(object, JSDataView::BodyDescriptor::kStartOffset),
+ HeapObject::RawField(object, JSDataView::kWeakNextOffset));
+ StaticVisitor::VisitPointers(
+ map->GetHeap(),
+ HeapObject::RawField(object, JSDataView::kWeakNextOffset + kPointerSize),
+ HeapObject::RawField(object, JSDataView::kSizeWithInternalFields));
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::MarkMapContents(Heap* heap,
+ Map* map) {
+ // Make sure that the back pointer stored either in the map itself or
+ // inside its transitions array is marked. Skip recording the back
+ // pointer slot since map space is not compacted.
+ StaticVisitor::MarkObject(heap, HeapObject::cast(map->GetBackPointer()));
+
+ // Treat pointers in the transitions array as weak and also mark that
+ // array to prevent visiting it later. Skip recording the transition
+ // array slot, since it will be implicitly recorded when the pointer
+ // fields of this map are visited.
+ if (map->HasTransitionArray()) {
+ TransitionArray* transitions = map->transitions();
+ MarkTransitionArray(heap, transitions);
+ }
+
+ // Since descriptor arrays are potentially shared, ensure that only the
+ // descriptors that belong to this map are marked. The first time a
+ // non-empty descriptor array is marked, its header is also visited. The slot
+ // holding the descriptor array will be implicitly recorded when the pointer
+ // fields of this map are visited.
+ DescriptorArray* descriptors = map->instance_descriptors();
+ if (StaticVisitor::MarkObjectWithoutPush(heap, descriptors) &&
+ descriptors->length() > 0) {
+ StaticVisitor::VisitPointers(heap, descriptors->GetFirstElementAddress(),
+ descriptors->GetDescriptorEndSlot(0));
+ }
+ int start = 0;
+ int end = map->NumberOfOwnDescriptors();
+ if (start < end) {
+ StaticVisitor::VisitPointers(heap,
+ descriptors->GetDescriptorStartSlot(start),
+ descriptors->GetDescriptorEndSlot(end));
+ }
+
+ // Mark prototype dependent codes array but do not push it onto marking
+ // stack, this will make references from it weak. We will clean dead
+ // codes when we iterate over maps in ClearNonLiveTransitions.
+ Object** slot = HeapObject::RawField(map, Map::kDependentCodeOffset);
+ HeapObject* obj = HeapObject::cast(*slot);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, obj);
+ StaticVisitor::MarkObjectWithoutPush(heap, obj);
+
+ // Mark the pointer fields of the Map. Since the transitions array has
+ // been marked already, it is fine that one of these fields contains a
+ // pointer to it.
+ StaticVisitor::VisitPointers(
+ heap, HeapObject::RawField(map, Map::kPointerFieldsBeginOffset),
+ HeapObject::RawField(map, Map::kPointerFieldsEndOffset));
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::MarkTransitionArray(
+ Heap* heap, TransitionArray* transitions) {
+ if (!StaticVisitor::MarkObjectWithoutPush(heap, transitions)) return;
+
+ // Simple transitions do not have keys nor prototype transitions.
+ if (transitions->IsSimpleTransition()) return;
+
+ if (transitions->HasPrototypeTransitions()) {
+ // Mark prototype transitions array but do not push it onto marking
+ // stack, this will make references from it weak. We will clean dead
+ // prototype transitions in ClearNonLiveTransitions.
+ Object** slot = transitions->GetPrototypeTransitionsSlot();
+ HeapObject* obj = HeapObject::cast(*slot);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, obj);
+ StaticVisitor::MarkObjectWithoutPush(heap, obj);
+ }
+
+ for (int i = 0; i < transitions->number_of_transitions(); ++i) {
+ StaticVisitor::VisitPointer(heap, transitions->GetKeySlot(i));
+ }
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::MarkInlinedFunctionsCode(Heap* heap,
+ Code* code) {
+ // Skip in absence of inlining.
+ // TODO(turbofan): Revisit once we support inlining.
+ if (code->is_turbofanned()) return;
+ // For optimized functions we should retain both non-optimized version
+ // of its code and non-optimized version of all inlined functions.
+ // This is required to support bailing out from inlined code.
+ DeoptimizationInputData* data =
+ DeoptimizationInputData::cast(code->deoptimization_data());
+ FixedArray* literals = data->LiteralArray();
+ for (int i = 0, count = data->InlinedFunctionCount()->value(); i < count;
+ i++) {
+ JSFunction* inlined = JSFunction::cast(literals->get(i));
+ StaticVisitor::MarkObject(heap, inlined->shared()->code());
+ }
+}
+
+
+inline static bool IsValidNonBuiltinContext(Object* context) {
+ return context->IsContext() &&
+ !Context::cast(context)->global_object()->IsJSBuiltinsObject();
+}
+
+
+inline static bool HasSourceCode(Heap* heap, SharedFunctionInfo* info) {
+ Object* undefined = heap->undefined_value();
+ return (info->script() != undefined) &&
+ (reinterpret_cast<Script*>(info->script())->source() != undefined);
+}
+
+
+template <typename StaticVisitor>
+bool StaticMarkingVisitor<StaticVisitor>::IsFlushable(Heap* heap,
+ JSFunction* function) {
+ SharedFunctionInfo* shared_info = function->shared();
+
+ // Code is either on stack, in compilation cache or referenced
+ // by optimized version of function.
+ MarkBit code_mark = Marking::MarkBitFrom(function->code());
+ if (code_mark.Get()) {
+ return false;
+ }
+
+ // The function must have a valid context and not be a builtin.
+ if (!IsValidNonBuiltinContext(function->context())) {
+ return false;
+ }
+
+ // We do not (yet) flush code for optimized functions.
+ if (function->code() != shared_info->code()) {
+ return false;
+ }
+
+ // Check age of optimized code.
+ if (FLAG_age_code && !function->code()->IsOld()) {
+ return false;
+ }
+
+ return IsFlushable(heap, shared_info);
+}
+
+
+template <typename StaticVisitor>
+bool StaticMarkingVisitor<StaticVisitor>::IsFlushable(
+ Heap* heap, SharedFunctionInfo* shared_info) {
+ // Code is either on stack, in compilation cache or referenced
+ // by optimized version of function.
+ MarkBit code_mark = Marking::MarkBitFrom(shared_info->code());
+ if (code_mark.Get()) {
+ return false;
+ }
+
+ // The function must be compiled and have the source code available,
+ // to be able to recompile it in case we need the function again.
+ if (!(shared_info->is_compiled() && HasSourceCode(heap, shared_info))) {
+ return false;
+ }
+
+ // We never flush code for API functions.
+ Object* function_data = shared_info->function_data();
+ if (function_data->IsFunctionTemplateInfo()) {
+ return false;
+ }
+
+ // Only flush code for functions.
+ if (shared_info->code()->kind() != Code::FUNCTION) {
+ return false;
+ }
+
+ // Function must be lazy compilable.
+ if (!shared_info->allows_lazy_compilation()) {
+ return false;
+ }
+
+ // We do not (yet?) flush code for generator functions, because we don't know
+ // if there are still live activations (generator objects) on the heap.
+ if (shared_info->is_generator()) {
+ return false;
+ }
+
+ // If this is a full script wrapped in a function we do not flush the code.
+ if (shared_info->is_toplevel()) {
+ return false;
+ }
+
+ // If this is a function initialized with %SetCode then the one-to-one
+ // relation between SharedFunctionInfo and Code is broken.
+ if (shared_info->dont_flush()) {
+ return false;
+ }
+
+ // Check age of code. If code aging is disabled we never flush.
+ if (!FLAG_age_code || !shared_info->code()->IsOld()) {
+ return false;
+ }
+
+ return true;
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitSharedFunctionInfoStrongCode(
+ Heap* heap, HeapObject* object) {
+ Object** start_slot = HeapObject::RawField(
+ object, SharedFunctionInfo::BodyDescriptor::kStartOffset);
+ Object** end_slot = HeapObject::RawField(
+ object, SharedFunctionInfo::BodyDescriptor::kEndOffset);
+ StaticVisitor::VisitPointers(heap, start_slot, end_slot);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitSharedFunctionInfoWeakCode(
+ Heap* heap, HeapObject* object) {
+ Object** name_slot =
+ HeapObject::RawField(object, SharedFunctionInfo::kNameOffset);
+ StaticVisitor::VisitPointer(heap, name_slot);
+
+ // Skip visiting kCodeOffset as it is treated weakly here.
+ STATIC_ASSERT(SharedFunctionInfo::kNameOffset + kPointerSize ==
+ SharedFunctionInfo::kCodeOffset);
+ STATIC_ASSERT(SharedFunctionInfo::kCodeOffset + kPointerSize ==
+ SharedFunctionInfo::kOptimizedCodeMapOffset);
+
+ Object** start_slot =
+ HeapObject::RawField(object, SharedFunctionInfo::kOptimizedCodeMapOffset);
+ Object** end_slot = HeapObject::RawField(
+ object, SharedFunctionInfo::BodyDescriptor::kEndOffset);
+ StaticVisitor::VisitPointers(heap, start_slot, end_slot);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitJSFunctionStrongCode(
+ Heap* heap, HeapObject* object) {
+ Object** start_slot =
+ HeapObject::RawField(object, JSFunction::kPropertiesOffset);
+ Object** end_slot =
+ HeapObject::RawField(object, JSFunction::kCodeEntryOffset);
+ StaticVisitor::VisitPointers(heap, start_slot, end_slot);
+
+ VisitCodeEntry(heap, object->address() + JSFunction::kCodeEntryOffset);
+ STATIC_ASSERT(JSFunction::kCodeEntryOffset + kPointerSize ==
+ JSFunction::kPrototypeOrInitialMapOffset);
+
+ start_slot =
+ HeapObject::RawField(object, JSFunction::kPrototypeOrInitialMapOffset);
+ end_slot = HeapObject::RawField(object, JSFunction::kNonWeakFieldsEndOffset);
+ StaticVisitor::VisitPointers(heap, start_slot, end_slot);
+}
+
+
+template <typename StaticVisitor>
+void StaticMarkingVisitor<StaticVisitor>::VisitJSFunctionWeakCode(
+ Heap* heap, HeapObject* object) {
+ Object** start_slot =
+ HeapObject::RawField(object, JSFunction::kPropertiesOffset);
+ Object** end_slot =
+ HeapObject::RawField(object, JSFunction::kCodeEntryOffset);
+ StaticVisitor::VisitPointers(heap, start_slot, end_slot);
+
+ // Skip visiting kCodeEntryOffset as it is treated weakly here.
+ STATIC_ASSERT(JSFunction::kCodeEntryOffset + kPointerSize ==
+ JSFunction::kPrototypeOrInitialMapOffset);
+
+ start_slot =
+ HeapObject::RawField(object, JSFunction::kPrototypeOrInitialMapOffset);
+ end_slot = HeapObject::RawField(object, JSFunction::kNonWeakFieldsEndOffset);
+ StaticVisitor::VisitPointers(heap, start_slot, end_slot);
+}
+
+
+void Code::CodeIterateBody(ObjectVisitor* v) {
+ int mode_mask = RelocInfo::kCodeTargetMask |
+ RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
+ RelocInfo::ModeMask(RelocInfo::CELL) |
+ RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
+ RelocInfo::ModeMask(RelocInfo::JS_RETURN) |
+ RelocInfo::ModeMask(RelocInfo::DEBUG_BREAK_SLOT) |
+ RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
+
+ // There are two places where we iterate code bodies: here and the
+ // templated CodeIterateBody (below). They should be kept in sync.
+ IteratePointer(v, kRelocationInfoOffset);
+ IteratePointer(v, kHandlerTableOffset);
+ IteratePointer(v, kDeoptimizationDataOffset);
+ IteratePointer(v, kTypeFeedbackInfoOffset);
+ IterateNextCodeLink(v, kNextCodeLinkOffset);
+ IteratePointer(v, kConstantPoolOffset);
+
+ RelocIterator it(this, mode_mask);
+ Isolate* isolate = this->GetIsolate();
+ for (; !it.done(); it.next()) {
+ it.rinfo()->Visit(isolate, v);
+ }
+}
+
+
+template <typename StaticVisitor>
+void Code::CodeIterateBody(Heap* heap) {
+ int mode_mask = RelocInfo::kCodeTargetMask |
+ RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
+ RelocInfo::ModeMask(RelocInfo::CELL) |
+ RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
+ RelocInfo::ModeMask(RelocInfo::JS_RETURN) |
+ RelocInfo::ModeMask(RelocInfo::DEBUG_BREAK_SLOT) |
+ RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY);
+
+ // There are two places where we iterate code bodies: here and the non-
+ // templated CodeIterateBody (above). They should be kept in sync.
+ StaticVisitor::VisitPointer(
+ heap,
+ reinterpret_cast<Object**>(this->address() + kRelocationInfoOffset));
+ StaticVisitor::VisitPointer(
+ heap, reinterpret_cast<Object**>(this->address() + kHandlerTableOffset));
+ StaticVisitor::VisitPointer(
+ heap,
+ reinterpret_cast<Object**>(this->address() + kDeoptimizationDataOffset));
+ StaticVisitor::VisitPointer(
+ heap,
+ reinterpret_cast<Object**>(this->address() + kTypeFeedbackInfoOffset));
+ StaticVisitor::VisitNextCodeLink(
+ heap, reinterpret_cast<Object**>(this->address() + kNextCodeLinkOffset));
+ StaticVisitor::VisitPointer(
+ heap, reinterpret_cast<Object**>(this->address() + kConstantPoolOffset));
+
+
+ RelocIterator it(this, mode_mask);
+ for (; !it.done(); it.next()) {
+ it.rinfo()->template Visit<StaticVisitor>(heap);
+ }
+}
+}
+} // namespace v8::internal
+
+#endif // V8_OBJECTS_VISITING_INL_H_
diff --git a/src/heap/objects-visiting.cc b/src/heap/objects-visiting.cc
new file mode 100644
index 0000000..a0fc231
--- /dev/null
+++ b/src/heap/objects-visiting.cc
@@ -0,0 +1,413 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#include "src/heap/objects-visiting.h"
+
+namespace v8 {
+namespace internal {
+
+
+StaticVisitorBase::VisitorId StaticVisitorBase::GetVisitorId(
+ int instance_type, int instance_size) {
+ if (instance_type < FIRST_NONSTRING_TYPE) {
+ switch (instance_type & kStringRepresentationMask) {
+ case kSeqStringTag:
+ if ((instance_type & kStringEncodingMask) == kOneByteStringTag) {
+ return kVisitSeqOneByteString;
+ } else {
+ return kVisitSeqTwoByteString;
+ }
+
+ case kConsStringTag:
+ if (IsShortcutCandidate(instance_type)) {
+ return kVisitShortcutCandidate;
+ } else {
+ return kVisitConsString;
+ }
+
+ case kSlicedStringTag:
+ return kVisitSlicedString;
+
+ case kExternalStringTag:
+ return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric,
+ instance_size);
+ }
+ UNREACHABLE();
+ }
+
+ switch (instance_type) {
+ case BYTE_ARRAY_TYPE:
+ return kVisitByteArray;
+
+ case FREE_SPACE_TYPE:
+ return kVisitFreeSpace;
+
+ case FIXED_ARRAY_TYPE:
+ return kVisitFixedArray;
+
+ case FIXED_DOUBLE_ARRAY_TYPE:
+ return kVisitFixedDoubleArray;
+
+ case CONSTANT_POOL_ARRAY_TYPE:
+ return kVisitConstantPoolArray;
+
+ case ODDBALL_TYPE:
+ return kVisitOddball;
+
+ case MAP_TYPE:
+ return kVisitMap;
+
+ case CODE_TYPE:
+ return kVisitCode;
+
+ case CELL_TYPE:
+ return kVisitCell;
+
+ case PROPERTY_CELL_TYPE:
+ return kVisitPropertyCell;
+
+ case JS_SET_TYPE:
+ return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
+ JSSet::kSize);
+
+ case JS_MAP_TYPE:
+ return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
+ JSMap::kSize);
+
+ case JS_WEAK_MAP_TYPE:
+ case JS_WEAK_SET_TYPE:
+ return kVisitJSWeakCollection;
+
+ case JS_REGEXP_TYPE:
+ return kVisitJSRegExp;
+
+ case SHARED_FUNCTION_INFO_TYPE:
+ return kVisitSharedFunctionInfo;
+
+ case JS_PROXY_TYPE:
+ return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
+ JSProxy::kSize);
+
+ case JS_FUNCTION_PROXY_TYPE:
+ return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
+ JSFunctionProxy::kSize);
+
+ case FOREIGN_TYPE:
+ return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric,
+ Foreign::kSize);
+
+ case SYMBOL_TYPE:
+ return kVisitSymbol;
+
+ case FILLER_TYPE:
+ return kVisitDataObjectGeneric;
+
+ case JS_ARRAY_BUFFER_TYPE:
+ return kVisitJSArrayBuffer;
+
+ case JS_TYPED_ARRAY_TYPE:
+ return kVisitJSTypedArray;
+
+ case JS_DATA_VIEW_TYPE:
+ return kVisitJSDataView;
+
+ case JS_OBJECT_TYPE:
+ case JS_CONTEXT_EXTENSION_OBJECT_TYPE:
+ case JS_GENERATOR_OBJECT_TYPE:
+ case JS_MODULE_TYPE:
+ case JS_VALUE_TYPE:
+ case JS_DATE_TYPE:
+ case JS_ARRAY_TYPE:
+ case JS_GLOBAL_PROXY_TYPE:
+ case JS_GLOBAL_OBJECT_TYPE:
+ case JS_BUILTINS_OBJECT_TYPE:
+ case JS_MESSAGE_OBJECT_TYPE:
+ case JS_SET_ITERATOR_TYPE:
+ case JS_MAP_ITERATOR_TYPE:
+ return GetVisitorIdForSize(kVisitJSObject, kVisitJSObjectGeneric,
+ instance_size);
+
+ case JS_FUNCTION_TYPE:
+ return kVisitJSFunction;
+
+ case HEAP_NUMBER_TYPE:
+ case MUTABLE_HEAP_NUMBER_TYPE:
+#define EXTERNAL_ARRAY_CASE(Type, type, TYPE, ctype, size) \
+ case EXTERNAL_##TYPE##_ARRAY_TYPE:
+
+ TYPED_ARRAYS(EXTERNAL_ARRAY_CASE)
+ return GetVisitorIdForSize(kVisitDataObject, kVisitDataObjectGeneric,
+ instance_size);
+#undef EXTERNAL_ARRAY_CASE
+
+ case FIXED_UINT8_ARRAY_TYPE:
+ case FIXED_INT8_ARRAY_TYPE:
+ case FIXED_UINT16_ARRAY_TYPE:
+ case FIXED_INT16_ARRAY_TYPE:
+ case FIXED_UINT32_ARRAY_TYPE:
+ case FIXED_INT32_ARRAY_TYPE:
+ case FIXED_FLOAT32_ARRAY_TYPE:
+ case FIXED_UINT8_CLAMPED_ARRAY_TYPE:
+ return kVisitFixedTypedArray;
+
+ case FIXED_FLOAT64_ARRAY_TYPE:
+ return kVisitFixedFloat64Array;
+
+#define MAKE_STRUCT_CASE(NAME, Name, name) case NAME##_TYPE:
+ STRUCT_LIST(MAKE_STRUCT_CASE)
+#undef MAKE_STRUCT_CASE
+ if (instance_type == ALLOCATION_SITE_TYPE) {
+ return kVisitAllocationSite;
+ }
+
+ return GetVisitorIdForSize(kVisitStruct, kVisitStructGeneric,
+ instance_size);
+
+ default:
+ UNREACHABLE();
+ return kVisitorIdCount;
+ }
+}
+
+
+// We don't record weak slots during marking or scavenges. Instead we do it
+// once when we complete mark-compact cycle. Note that write barrier has no
+// effect if we are already in the middle of compacting mark-sweep cycle and we
+// have to record slots manually.
+static bool MustRecordSlots(Heap* heap) {
+ return heap->gc_state() == Heap::MARK_COMPACT &&
+ heap->mark_compact_collector()->is_compacting();
+}
+
+
+template <class T>
+struct WeakListVisitor;
+
+
+template <class T>
+Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer) {
+ Object* undefined = heap->undefined_value();
+ Object* head = undefined;
+ T* tail = NULL;
+ MarkCompactCollector* collector = heap->mark_compact_collector();
+ bool record_slots = MustRecordSlots(heap);
+ while (list != undefined) {
+ // Check whether to keep the candidate in the list.
+ T* candidate = reinterpret_cast<T*>(list);
+ Object* retained = retainer->RetainAs(list);
+ if (retained != NULL) {
+ if (head == undefined) {
+ // First element in the list.
+ head = retained;
+ } else {
+ // Subsequent elements in the list.
+ DCHECK(tail != NULL);
+ WeakListVisitor<T>::SetWeakNext(tail, retained);
+ if (record_slots) {
+ Object** next_slot =
+ HeapObject::RawField(tail, WeakListVisitor<T>::WeakNextOffset());
+ collector->RecordSlot(next_slot, next_slot, retained);
+ }
+ }
+ // Retained object is new tail.
+ DCHECK(!retained->IsUndefined());
+ candidate = reinterpret_cast<T*>(retained);
+ tail = candidate;
+
+
+ // tail is a live object, visit it.
+ WeakListVisitor<T>::VisitLiveObject(heap, tail, retainer);
+ } else {
+ WeakListVisitor<T>::VisitPhantomObject(heap, candidate);
+ }
+
+ // Move to next element in the list.
+ list = WeakListVisitor<T>::WeakNext(candidate);
+ }
+
+ // Terminate the list if there is one or more elements.
+ if (tail != NULL) {
+ WeakListVisitor<T>::SetWeakNext(tail, undefined);
+ }
+ return head;
+}
+
+
+template <class T>
+static void ClearWeakList(Heap* heap, Object* list) {
+ Object* undefined = heap->undefined_value();
+ while (list != undefined) {
+ T* candidate = reinterpret_cast<T*>(list);
+ list = WeakListVisitor<T>::WeakNext(candidate);
+ WeakListVisitor<T>::SetWeakNext(candidate, undefined);
+ }
+}
+
+
+template <>
+struct WeakListVisitor<JSFunction> {
+ static void SetWeakNext(JSFunction* function, Object* next) {
+ function->set_next_function_link(next);
+ }
+
+ static Object* WeakNext(JSFunction* function) {
+ return function->next_function_link();
+ }
+
+ static int WeakNextOffset() { return JSFunction::kNextFunctionLinkOffset; }
+
+ static void VisitLiveObject(Heap*, JSFunction*, WeakObjectRetainer*) {}
+
+ static void VisitPhantomObject(Heap*, JSFunction*) {}
+};
+
+
+template <>
+struct WeakListVisitor<Code> {
+ static void SetWeakNext(Code* code, Object* next) {
+ code->set_next_code_link(next);
+ }
+
+ static Object* WeakNext(Code* code) { return code->next_code_link(); }
+
+ static int WeakNextOffset() { return Code::kNextCodeLinkOffset; }
+
+ static void VisitLiveObject(Heap*, Code*, WeakObjectRetainer*) {}
+
+ static void VisitPhantomObject(Heap*, Code*) {}
+};
+
+
+template <>
+struct WeakListVisitor<Context> {
+ static void SetWeakNext(Context* context, Object* next) {
+ context->set(Context::NEXT_CONTEXT_LINK, next, UPDATE_WRITE_BARRIER);
+ }
+
+ static Object* WeakNext(Context* context) {
+ return context->get(Context::NEXT_CONTEXT_LINK);
+ }
+
+ static int WeakNextOffset() {
+ return FixedArray::SizeFor(Context::NEXT_CONTEXT_LINK);
+ }
+
+ static void VisitLiveObject(Heap* heap, Context* context,
+ WeakObjectRetainer* retainer) {
+ // Process the three weak lists linked off the context.
+ DoWeakList<JSFunction>(heap, context, retainer,
+ Context::OPTIMIZED_FUNCTIONS_LIST);
+ DoWeakList<Code>(heap, context, retainer, Context::OPTIMIZED_CODE_LIST);
+ DoWeakList<Code>(heap, context, retainer, Context::DEOPTIMIZED_CODE_LIST);
+ }
+
+ template <class T>
+ static void DoWeakList(Heap* heap, Context* context,
+ WeakObjectRetainer* retainer, int index) {
+ // Visit the weak list, removing dead intermediate elements.
+ Object* list_head = VisitWeakList<T>(heap, context->get(index), retainer);
+
+ // Update the list head.
+ context->set(index, list_head, UPDATE_WRITE_BARRIER);
+
+ if (MustRecordSlots(heap)) {
+ // Record the updated slot if necessary.
+ Object** head_slot =
+ HeapObject::RawField(context, FixedArray::SizeFor(index));
+ heap->mark_compact_collector()->RecordSlot(head_slot, head_slot,
+ list_head);
+ }
+ }
+
+ static void VisitPhantomObject(Heap* heap, Context* context) {
+ ClearWeakList<JSFunction>(heap,
+ context->get(Context::OPTIMIZED_FUNCTIONS_LIST));
+ ClearWeakList<Code>(heap, context->get(Context::OPTIMIZED_CODE_LIST));
+ ClearWeakList<Code>(heap, context->get(Context::DEOPTIMIZED_CODE_LIST));
+ }
+};
+
+
+template <>
+struct WeakListVisitor<JSArrayBufferView> {
+ static void SetWeakNext(JSArrayBufferView* obj, Object* next) {
+ obj->set_weak_next(next);
+ }
+
+ static Object* WeakNext(JSArrayBufferView* obj) { return obj->weak_next(); }
+
+ static int WeakNextOffset() { return JSArrayBufferView::kWeakNextOffset; }
+
+ static void VisitLiveObject(Heap*, JSArrayBufferView*, WeakObjectRetainer*) {}
+
+ static void VisitPhantomObject(Heap*, JSArrayBufferView*) {}
+};
+
+
+template <>
+struct WeakListVisitor<JSArrayBuffer> {
+ static void SetWeakNext(JSArrayBuffer* obj, Object* next) {
+ obj->set_weak_next(next);
+ }
+
+ static Object* WeakNext(JSArrayBuffer* obj) { return obj->weak_next(); }
+
+ static int WeakNextOffset() { return JSArrayBuffer::kWeakNextOffset; }
+
+ static void VisitLiveObject(Heap* heap, JSArrayBuffer* array_buffer,
+ WeakObjectRetainer* retainer) {
+ Object* typed_array_obj = VisitWeakList<JSArrayBufferView>(
+ heap, array_buffer->weak_first_view(), retainer);
+ array_buffer->set_weak_first_view(typed_array_obj);
+ if (typed_array_obj != heap->undefined_value() && MustRecordSlots(heap)) {
+ Object** slot = HeapObject::RawField(array_buffer,
+ JSArrayBuffer::kWeakFirstViewOffset);
+ heap->mark_compact_collector()->RecordSlot(slot, slot, typed_array_obj);
+ }
+ }
+
+ static void VisitPhantomObject(Heap* heap, JSArrayBuffer* phantom) {
+ Runtime::FreeArrayBuffer(heap->isolate(), phantom);
+ }
+};
+
+
+template <>
+struct WeakListVisitor<AllocationSite> {
+ static void SetWeakNext(AllocationSite* obj, Object* next) {
+ obj->set_weak_next(next);
+ }
+
+ static Object* WeakNext(AllocationSite* obj) { return obj->weak_next(); }
+
+ static int WeakNextOffset() { return AllocationSite::kWeakNextOffset; }
+
+ static void VisitLiveObject(Heap*, AllocationSite*, WeakObjectRetainer*) {}
+
+ static void VisitPhantomObject(Heap*, AllocationSite*) {}
+};
+
+
+template Object* VisitWeakList<Code>(Heap* heap, Object* list,
+ WeakObjectRetainer* retainer);
+
+
+template Object* VisitWeakList<JSFunction>(Heap* heap, Object* list,
+ WeakObjectRetainer* retainer);
+
+
+template Object* VisitWeakList<Context>(Heap* heap, Object* list,
+ WeakObjectRetainer* retainer);
+
+
+template Object* VisitWeakList<JSArrayBuffer>(Heap* heap, Object* list,
+ WeakObjectRetainer* retainer);
+
+
+template Object* VisitWeakList<AllocationSite>(Heap* heap, Object* list,
+ WeakObjectRetainer* retainer);
+}
+} // namespace v8::internal
diff --git a/src/heap/objects-visiting.h b/src/heap/objects-visiting.h
new file mode 100644
index 0000000..919a800
--- /dev/null
+++ b/src/heap/objects-visiting.h
@@ -0,0 +1,452 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_OBJECTS_VISITING_H_
+#define V8_OBJECTS_VISITING_H_
+
+#include "src/allocation.h"
+
+// This file provides base classes and auxiliary methods for defining
+// static object visitors used during GC.
+// Visiting HeapObject body with a normal ObjectVisitor requires performing
+// two switches on object's instance type to determine object size and layout
+// and one or more virtual method calls on visitor itself.
+// Static visitor is different: it provides a dispatch table which contains
+// pointers to specialized visit functions. Each map has the visitor_id
+// field which contains an index of specialized visitor to use.
+
+namespace v8 {
+namespace internal {
+
+
+// Base class for all static visitors.
+class StaticVisitorBase : public AllStatic {
+ public:
+#define VISITOR_ID_LIST(V) \
+ V(SeqOneByteString) \
+ V(SeqTwoByteString) \
+ V(ShortcutCandidate) \
+ V(ByteArray) \
+ V(FreeSpace) \
+ V(FixedArray) \
+ V(FixedDoubleArray) \
+ V(FixedTypedArray) \
+ V(FixedFloat64Array) \
+ V(ConstantPoolArray) \
+ V(NativeContext) \
+ V(AllocationSite) \
+ V(DataObject2) \
+ V(DataObject3) \
+ V(DataObject4) \
+ V(DataObject5) \
+ V(DataObject6) \
+ V(DataObject7) \
+ V(DataObject8) \
+ V(DataObject9) \
+ V(DataObjectGeneric) \
+ V(JSObject2) \
+ V(JSObject3) \
+ V(JSObject4) \
+ V(JSObject5) \
+ V(JSObject6) \
+ V(JSObject7) \
+ V(JSObject8) \
+ V(JSObject9) \
+ V(JSObjectGeneric) \
+ V(Struct2) \
+ V(Struct3) \
+ V(Struct4) \
+ V(Struct5) \
+ V(Struct6) \
+ V(Struct7) \
+ V(Struct8) \
+ V(Struct9) \
+ V(StructGeneric) \
+ V(ConsString) \
+ V(SlicedString) \
+ V(Symbol) \
+ V(Oddball) \
+ V(Code) \
+ V(Map) \
+ V(Cell) \
+ V(PropertyCell) \
+ V(SharedFunctionInfo) \
+ V(JSFunction) \
+ V(JSWeakCollection) \
+ V(JSArrayBuffer) \
+ V(JSTypedArray) \
+ V(JSDataView) \
+ V(JSRegExp)
+
+ // For data objects, JS objects and structs along with generic visitor which
+ // can visit object of any size we provide visitors specialized by
+ // object size in words.
+ // Ids of specialized visitors are declared in a linear order (without
+ // holes) starting from the id of visitor specialized for 2 words objects
+ // (base visitor id) and ending with the id of generic visitor.
+ // Method GetVisitorIdForSize depends on this ordering to calculate visitor
+ // id of specialized visitor from given instance size, base visitor id and
+ // generic visitor's id.
+ enum VisitorId {
+#define VISITOR_ID_ENUM_DECL(id) kVisit##id,
+ VISITOR_ID_LIST(VISITOR_ID_ENUM_DECL)
+#undef VISITOR_ID_ENUM_DECL
+ kVisitorIdCount,
+ kVisitDataObject = kVisitDataObject2,
+ kVisitJSObject = kVisitJSObject2,
+ kVisitStruct = kVisitStruct2,
+ kMinObjectSizeInWords = 2
+ };
+
+ // Visitor ID should fit in one byte.
+ STATIC_ASSERT(kVisitorIdCount <= 256);
+
+ // Determine which specialized visitor should be used for given instance type
+ // and instance type.
+ static VisitorId GetVisitorId(int instance_type, int instance_size);
+
+ static VisitorId GetVisitorId(Map* map) {
+ return GetVisitorId(map->instance_type(), map->instance_size());
+ }
+
+ // For visitors that allow specialization by size calculate VisitorId based
+ // on size, base visitor id and generic visitor id.
+ static VisitorId GetVisitorIdForSize(VisitorId base, VisitorId generic,
+ int object_size) {
+ DCHECK((base == kVisitDataObject) || (base == kVisitStruct) ||
+ (base == kVisitJSObject));
+ DCHECK(IsAligned(object_size, kPointerSize));
+ DCHECK(kMinObjectSizeInWords * kPointerSize <= object_size);
+ DCHECK(object_size <= Page::kMaxRegularHeapObjectSize);
+
+ const VisitorId specialization = static_cast<VisitorId>(
+ base + (object_size >> kPointerSizeLog2) - kMinObjectSizeInWords);
+
+ return Min(specialization, generic);
+ }
+};
+
+
+template <typename Callback>
+class VisitorDispatchTable {
+ public:
+ void CopyFrom(VisitorDispatchTable* other) {
+ // We are not using memcpy to guarantee that during update
+ // every element of callbacks_ array will remain correct
+ // pointer (memcpy might be implemented as a byte copying loop).
+ for (int i = 0; i < StaticVisitorBase::kVisitorIdCount; i++) {
+ base::NoBarrier_Store(&callbacks_[i], other->callbacks_[i]);
+ }
+ }
+
+ inline Callback GetVisitorById(StaticVisitorBase::VisitorId id) {
+ return reinterpret_cast<Callback>(callbacks_[id]);
+ }
+
+ inline Callback GetVisitor(Map* map) {
+ return reinterpret_cast<Callback>(callbacks_[map->visitor_id()]);
+ }
+
+ void Register(StaticVisitorBase::VisitorId id, Callback callback) {
+ DCHECK(id < StaticVisitorBase::kVisitorIdCount); // id is unsigned.
+ callbacks_[id] = reinterpret_cast<base::AtomicWord>(callback);
+ }
+
+ template <typename Visitor, StaticVisitorBase::VisitorId base,
+ StaticVisitorBase::VisitorId generic, int object_size_in_words>
+ void RegisterSpecialization() {
+ static const int size = object_size_in_words * kPointerSize;
+ Register(StaticVisitorBase::GetVisitorIdForSize(base, generic, size),
+ &Visitor::template VisitSpecialized<size>);
+ }
+
+
+ template <typename Visitor, StaticVisitorBase::VisitorId base,
+ StaticVisitorBase::VisitorId generic>
+ void RegisterSpecializations() {
+ STATIC_ASSERT((generic - base + StaticVisitorBase::kMinObjectSizeInWords) ==
+ 10);
+ RegisterSpecialization<Visitor, base, generic, 2>();
+ RegisterSpecialization<Visitor, base, generic, 3>();
+ RegisterSpecialization<Visitor, base, generic, 4>();
+ RegisterSpecialization<Visitor, base, generic, 5>();
+ RegisterSpecialization<Visitor, base, generic, 6>();
+ RegisterSpecialization<Visitor, base, generic, 7>();
+ RegisterSpecialization<Visitor, base, generic, 8>();
+ RegisterSpecialization<Visitor, base, generic, 9>();
+ Register(generic, &Visitor::Visit);
+ }
+
+ private:
+ base::AtomicWord callbacks_[StaticVisitorBase::kVisitorIdCount];
+};
+
+
+template <typename StaticVisitor>
+class BodyVisitorBase : public AllStatic {
+ public:
+ INLINE(static void IteratePointers(Heap* heap, HeapObject* object,
+ int start_offset, int end_offset)) {
+ Object** start_slot =
+ reinterpret_cast<Object**>(object->address() + start_offset);
+ Object** end_slot =
+ reinterpret_cast<Object**>(object->address() + end_offset);
+ StaticVisitor::VisitPointers(heap, start_slot, end_slot);
+ }
+};
+
+
+template <typename StaticVisitor, typename BodyDescriptor, typename ReturnType>
+class FlexibleBodyVisitor : public BodyVisitorBase<StaticVisitor> {
+ public:
+ INLINE(static ReturnType Visit(Map* map, HeapObject* object)) {
+ int object_size = BodyDescriptor::SizeOf(map, object);
+ BodyVisitorBase<StaticVisitor>::IteratePointers(
+ map->GetHeap(), object, BodyDescriptor::kStartOffset, object_size);
+ return static_cast<ReturnType>(object_size);
+ }
+
+ template <int object_size>
+ static inline ReturnType VisitSpecialized(Map* map, HeapObject* object) {
+ DCHECK(BodyDescriptor::SizeOf(map, object) == object_size);
+ BodyVisitorBase<StaticVisitor>::IteratePointers(
+ map->GetHeap(), object, BodyDescriptor::kStartOffset, object_size);
+ return static_cast<ReturnType>(object_size);
+ }
+};
+
+
+template <typename StaticVisitor, typename BodyDescriptor, typename ReturnType>
+class FixedBodyVisitor : public BodyVisitorBase<StaticVisitor> {
+ public:
+ INLINE(static ReturnType Visit(Map* map, HeapObject* object)) {
+ BodyVisitorBase<StaticVisitor>::IteratePointers(
+ map->GetHeap(), object, BodyDescriptor::kStartOffset,
+ BodyDescriptor::kEndOffset);
+ return static_cast<ReturnType>(BodyDescriptor::kSize);
+ }
+};
+
+
+// Base class for visitors used for a linear new space iteration.
+// IterateBody returns size of visited object.
+// Certain types of objects (i.e. Code objects) are not handled
+// by dispatch table of this visitor because they cannot appear
+// in the new space.
+//
+// This class is intended to be used in the following way:
+//
+// class SomeVisitor : public StaticNewSpaceVisitor<SomeVisitor> {
+// ...
+// }
+//
+// This is an example of Curiously recurring template pattern
+// (see http://en.wikipedia.org/wiki/Curiously_recurring_template_pattern).
+// We use CRTP to guarantee aggressive compile time optimizations (i.e.
+// inlining and specialization of StaticVisitor::VisitPointers methods).
+template <typename StaticVisitor>
+class StaticNewSpaceVisitor : public StaticVisitorBase {
+ public:
+ static void Initialize();
+
+ INLINE(static int IterateBody(Map* map, HeapObject* obj)) {
+ return table_.GetVisitor(map)(map, obj);
+ }
+
+ INLINE(static void VisitPointers(Heap* heap, Object** start, Object** end)) {
+ for (Object** p = start; p < end; p++) StaticVisitor::VisitPointer(heap, p);
+ }
+
+ private:
+ INLINE(static int VisitJSFunction(Map* map, HeapObject* object)) {
+ Heap* heap = map->GetHeap();
+ VisitPointers(heap,
+ HeapObject::RawField(object, JSFunction::kPropertiesOffset),
+ HeapObject::RawField(object, JSFunction::kCodeEntryOffset));
+
+ // Don't visit code entry. We are using this visitor only during scavenges.
+
+ VisitPointers(
+ heap, HeapObject::RawField(object,
+ JSFunction::kCodeEntryOffset + kPointerSize),
+ HeapObject::RawField(object, JSFunction::kNonWeakFieldsEndOffset));
+ return JSFunction::kSize;
+ }
+
+ INLINE(static int VisitByteArray(Map* map, HeapObject* object)) {
+ return reinterpret_cast<ByteArray*>(object)->ByteArraySize();
+ }
+
+ INLINE(static int VisitFixedDoubleArray(Map* map, HeapObject* object)) {
+ int length = reinterpret_cast<FixedDoubleArray*>(object)->length();
+ return FixedDoubleArray::SizeFor(length);
+ }
+
+ INLINE(static int VisitFixedTypedArray(Map* map, HeapObject* object)) {
+ return reinterpret_cast<FixedTypedArrayBase*>(object)->size();
+ }
+
+ INLINE(static int VisitJSObject(Map* map, HeapObject* object)) {
+ return JSObjectVisitor::Visit(map, object);
+ }
+
+ INLINE(static int VisitSeqOneByteString(Map* map, HeapObject* object)) {
+ return SeqOneByteString::cast(object)
+ ->SeqOneByteStringSize(map->instance_type());
+ }
+
+ INLINE(static int VisitSeqTwoByteString(Map* map, HeapObject* object)) {
+ return SeqTwoByteString::cast(object)
+ ->SeqTwoByteStringSize(map->instance_type());
+ }
+
+ INLINE(static int VisitFreeSpace(Map* map, HeapObject* object)) {
+ return FreeSpace::cast(object)->Size();
+ }
+
+ INLINE(static int VisitJSArrayBuffer(Map* map, HeapObject* object));
+ INLINE(static int VisitJSTypedArray(Map* map, HeapObject* object));
+ INLINE(static int VisitJSDataView(Map* map, HeapObject* object));
+
+ class DataObjectVisitor {
+ public:
+ template <int object_size>
+ static inline int VisitSpecialized(Map* map, HeapObject* object) {
+ return object_size;
+ }
+
+ INLINE(static int Visit(Map* map, HeapObject* object)) {
+ return map->instance_size();
+ }
+ };
+
+ typedef FlexibleBodyVisitor<StaticVisitor, StructBodyDescriptor, int>
+ StructVisitor;
+
+ typedef FlexibleBodyVisitor<StaticVisitor, JSObject::BodyDescriptor, int>
+ JSObjectVisitor;
+
+ typedef int (*Callback)(Map* map, HeapObject* object);
+
+ static VisitorDispatchTable<Callback> table_;
+};
+
+
+template <typename StaticVisitor>
+VisitorDispatchTable<typename StaticNewSpaceVisitor<StaticVisitor>::Callback>
+ StaticNewSpaceVisitor<StaticVisitor>::table_;
+
+
+// Base class for visitors used to transitively mark the entire heap.
+// IterateBody returns nothing.
+// Certain types of objects might not be handled by this base class and
+// no visitor function is registered by the generic initialization. A
+// specialized visitor function needs to be provided by the inheriting
+// class itself for those cases.
+//
+// This class is intended to be used in the following way:
+//
+// class SomeVisitor : public StaticMarkingVisitor<SomeVisitor> {
+// ...
+// }
+//
+// This is an example of Curiously recurring template pattern.
+template <typename StaticVisitor>
+class StaticMarkingVisitor : public StaticVisitorBase {
+ public:
+ static void Initialize();
+
+ INLINE(static void IterateBody(Map* map, HeapObject* obj)) {
+ table_.GetVisitor(map)(map, obj);
+ }
+
+ INLINE(static void VisitPropertyCell(Map* map, HeapObject* object));
+ INLINE(static void VisitCodeEntry(Heap* heap, Address entry_address));
+ INLINE(static void VisitEmbeddedPointer(Heap* heap, RelocInfo* rinfo));
+ INLINE(static void VisitCell(Heap* heap, RelocInfo* rinfo));
+ INLINE(static void VisitDebugTarget(Heap* heap, RelocInfo* rinfo));
+ INLINE(static void VisitCodeTarget(Heap* heap, RelocInfo* rinfo));
+ INLINE(static void VisitCodeAgeSequence(Heap* heap, RelocInfo* rinfo));
+ INLINE(static void VisitExternalReference(RelocInfo* rinfo)) {}
+ INLINE(static void VisitRuntimeEntry(RelocInfo* rinfo)) {}
+ // Skip the weak next code link in a code object.
+ INLINE(static void VisitNextCodeLink(Heap* heap, Object** slot)) {}
+
+ // TODO(mstarzinger): This should be made protected once refactoring is done.
+ // Mark non-optimize code for functions inlined into the given optimized
+ // code. This will prevent it from being flushed.
+ static void MarkInlinedFunctionsCode(Heap* heap, Code* code);
+
+ protected:
+ INLINE(static void VisitMap(Map* map, HeapObject* object));
+ INLINE(static void VisitCode(Map* map, HeapObject* object));
+ INLINE(static void VisitSharedFunctionInfo(Map* map, HeapObject* object));
+ INLINE(static void VisitConstantPoolArray(Map* map, HeapObject* object));
+ INLINE(static void VisitAllocationSite(Map* map, HeapObject* object));
+ INLINE(static void VisitWeakCollection(Map* map, HeapObject* object));
+ INLINE(static void VisitJSFunction(Map* map, HeapObject* object));
+ INLINE(static void VisitJSRegExp(Map* map, HeapObject* object));
+ INLINE(static void VisitJSArrayBuffer(Map* map, HeapObject* object));
+ INLINE(static void VisitJSTypedArray(Map* map, HeapObject* object));
+ INLINE(static void VisitJSDataView(Map* map, HeapObject* object));
+ INLINE(static void VisitNativeContext(Map* map, HeapObject* object));
+
+ // Mark pointers in a Map and its TransitionArray together, possibly
+ // treating transitions or back pointers weak.
+ static void MarkMapContents(Heap* heap, Map* map);
+ static void MarkTransitionArray(Heap* heap, TransitionArray* transitions);
+
+ // Code flushing support.
+ INLINE(static bool IsFlushable(Heap* heap, JSFunction* function));
+ INLINE(static bool IsFlushable(Heap* heap, SharedFunctionInfo* shared_info));
+
+ // Helpers used by code flushing support that visit pointer fields and treat
+ // references to code objects either strongly or weakly.
+ static void VisitSharedFunctionInfoStrongCode(Heap* heap, HeapObject* object);
+ static void VisitSharedFunctionInfoWeakCode(Heap* heap, HeapObject* object);
+ static void VisitJSFunctionStrongCode(Heap* heap, HeapObject* object);
+ static void VisitJSFunctionWeakCode(Heap* heap, HeapObject* object);
+
+ class DataObjectVisitor {
+ public:
+ template <int size>
+ static inline void VisitSpecialized(Map* map, HeapObject* object) {}
+
+ INLINE(static void Visit(Map* map, HeapObject* object)) {}
+ };
+
+ typedef FlexibleBodyVisitor<StaticVisitor, FixedArray::BodyDescriptor, void>
+ FixedArrayVisitor;
+
+ typedef FlexibleBodyVisitor<StaticVisitor, JSObject::BodyDescriptor, void>
+ JSObjectVisitor;
+
+ typedef FlexibleBodyVisitor<StaticVisitor, StructBodyDescriptor, void>
+ StructObjectVisitor;
+
+ typedef void (*Callback)(Map* map, HeapObject* object);
+
+ static VisitorDispatchTable<Callback> table_;
+};
+
+
+template <typename StaticVisitor>
+VisitorDispatchTable<typename StaticMarkingVisitor<StaticVisitor>::Callback>
+ StaticMarkingVisitor<StaticVisitor>::table_;
+
+
+class WeakObjectRetainer;
+
+
+// A weak list is single linked list where each element has a weak pointer to
+// the next element. Given the head of the list, this function removes dead
+// elements from the list and if requested records slots for next-element
+// pointers. The template parameter T is a WeakListVisitor that defines how to
+// access the next-element pointers.
+template <class T>
+Object* VisitWeakList(Heap* heap, Object* list, WeakObjectRetainer* retainer);
+}
+} // namespace v8::internal
+
+#endif // V8_OBJECTS_VISITING_H_
diff --git a/src/heap/spaces-inl.h b/src/heap/spaces-inl.h
new file mode 100644
index 0000000..d81d253
--- /dev/null
+++ b/src/heap/spaces-inl.h
@@ -0,0 +1,313 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_SPACES_INL_H_
+#define V8_HEAP_SPACES_INL_H_
+
+#include "src/heap/spaces.h"
+#include "src/heap-profiler.h"
+#include "src/isolate.h"
+#include "src/msan.h"
+#include "src/v8memory.h"
+
+namespace v8 {
+namespace internal {
+
+
+// -----------------------------------------------------------------------------
+// Bitmap
+
+void Bitmap::Clear(MemoryChunk* chunk) {
+ Bitmap* bitmap = chunk->markbits();
+ for (int i = 0; i < bitmap->CellsCount(); i++) bitmap->cells()[i] = 0;
+ chunk->ResetLiveBytes();
+}
+
+
+// -----------------------------------------------------------------------------
+// PageIterator
+
+
+PageIterator::PageIterator(PagedSpace* space)
+ : space_(space),
+ prev_page_(&space->anchor_),
+ next_page_(prev_page_->next_page()) {}
+
+
+bool PageIterator::has_next() { return next_page_ != &space_->anchor_; }
+
+
+Page* PageIterator::next() {
+ DCHECK(has_next());
+ prev_page_ = next_page_;
+ next_page_ = next_page_->next_page();
+ return prev_page_;
+}
+
+
+// -----------------------------------------------------------------------------
+// NewSpacePageIterator
+
+
+NewSpacePageIterator::NewSpacePageIterator(NewSpace* space)
+ : prev_page_(NewSpacePage::FromAddress(space->ToSpaceStart())->prev_page()),
+ next_page_(NewSpacePage::FromAddress(space->ToSpaceStart())),
+ last_page_(NewSpacePage::FromLimit(space->ToSpaceEnd())) {}
+
+NewSpacePageIterator::NewSpacePageIterator(SemiSpace* space)
+ : prev_page_(space->anchor()),
+ next_page_(prev_page_->next_page()),
+ last_page_(prev_page_->prev_page()) {}
+
+NewSpacePageIterator::NewSpacePageIterator(Address start, Address limit)
+ : prev_page_(NewSpacePage::FromAddress(start)->prev_page()),
+ next_page_(NewSpacePage::FromAddress(start)),
+ last_page_(NewSpacePage::FromLimit(limit)) {
+ SemiSpace::AssertValidRange(start, limit);
+}
+
+
+bool NewSpacePageIterator::has_next() { return prev_page_ != last_page_; }
+
+
+NewSpacePage* NewSpacePageIterator::next() {
+ DCHECK(has_next());
+ prev_page_ = next_page_;
+ next_page_ = next_page_->next_page();
+ return prev_page_;
+}
+
+
+// -----------------------------------------------------------------------------
+// HeapObjectIterator
+HeapObject* HeapObjectIterator::FromCurrentPage() {
+ while (cur_addr_ != cur_end_) {
+ if (cur_addr_ == space_->top() && cur_addr_ != space_->limit()) {
+ cur_addr_ = space_->limit();
+ continue;
+ }
+ HeapObject* obj = HeapObject::FromAddress(cur_addr_);
+ int obj_size = (size_func_ == NULL) ? obj->Size() : size_func_(obj);
+ cur_addr_ += obj_size;
+ DCHECK(cur_addr_ <= cur_end_);
+ if (!obj->IsFiller()) {
+ DCHECK_OBJECT_SIZE(obj_size);
+ return obj;
+ }
+ }
+ return NULL;
+}
+
+
+// -----------------------------------------------------------------------------
+// MemoryAllocator
+
+#ifdef ENABLE_HEAP_PROTECTION
+
+void MemoryAllocator::Protect(Address start, size_t size) {
+ base::OS::Protect(start, size);
+}
+
+
+void MemoryAllocator::Unprotect(Address start, size_t size,
+ Executability executable) {
+ base::OS::Unprotect(start, size, executable);
+}
+
+
+void MemoryAllocator::ProtectChunkFromPage(Page* page) {
+ int id = GetChunkId(page);
+ base::OS::Protect(chunks_[id].address(), chunks_[id].size());
+}
+
+
+void MemoryAllocator::UnprotectChunkFromPage(Page* page) {
+ int id = GetChunkId(page);
+ base::OS::Unprotect(chunks_[id].address(), chunks_[id].size(),
+ chunks_[id].owner()->executable() == EXECUTABLE);
+}
+
+#endif
+
+
+// --------------------------------------------------------------------------
+// PagedSpace
+Page* Page::Initialize(Heap* heap, MemoryChunk* chunk, Executability executable,
+ PagedSpace* owner) {
+ Page* page = reinterpret_cast<Page*>(chunk);
+ DCHECK(page->area_size() <= kMaxRegularHeapObjectSize);
+ DCHECK(chunk->owner() == owner);
+ owner->IncreaseCapacity(page->area_size());
+ owner->Free(page->area_start(), page->area_size());
+
+ heap->incremental_marking()->SetOldSpacePageFlags(chunk);
+
+ return page;
+}
+
+
+bool PagedSpace::Contains(Address addr) {
+ Page* p = Page::FromAddress(addr);
+ if (!p->is_valid()) return false;
+ return p->owner() == this;
+}
+
+
+void MemoryChunk::set_scan_on_scavenge(bool scan) {
+ if (scan) {
+ if (!scan_on_scavenge()) heap_->increment_scan_on_scavenge_pages();
+ SetFlag(SCAN_ON_SCAVENGE);
+ } else {
+ if (scan_on_scavenge()) heap_->decrement_scan_on_scavenge_pages();
+ ClearFlag(SCAN_ON_SCAVENGE);
+ }
+ heap_->incremental_marking()->SetOldSpacePageFlags(this);
+}
+
+
+MemoryChunk* MemoryChunk::FromAnyPointerAddress(Heap* heap, Address addr) {
+ MemoryChunk* maybe = reinterpret_cast<MemoryChunk*>(
+ OffsetFrom(addr) & ~Page::kPageAlignmentMask);
+ if (maybe->owner() != NULL) return maybe;
+ LargeObjectIterator iterator(heap->lo_space());
+ for (HeapObject* o = iterator.Next(); o != NULL; o = iterator.Next()) {
+ // Fixed arrays are the only pointer-containing objects in large object
+ // space.
+ if (o->IsFixedArray()) {
+ MemoryChunk* chunk = MemoryChunk::FromAddress(o->address());
+ if (chunk->Contains(addr)) {
+ return chunk;
+ }
+ }
+ }
+ UNREACHABLE();
+ return NULL;
+}
+
+
+void MemoryChunk::UpdateHighWaterMark(Address mark) {
+ if (mark == NULL) return;
+ // Need to subtract one from the mark because when a chunk is full the
+ // top points to the next address after the chunk, which effectively belongs
+ // to another chunk. See the comment to Page::FromAllocationTop.
+ MemoryChunk* chunk = MemoryChunk::FromAddress(mark - 1);
+ int new_mark = static_cast<int>(mark - chunk->address());
+ if (new_mark > chunk->high_water_mark_) {
+ chunk->high_water_mark_ = new_mark;
+ }
+}
+
+
+PointerChunkIterator::PointerChunkIterator(Heap* heap)
+ : state_(kOldPointerState),
+ old_pointer_iterator_(heap->old_pointer_space()),
+ map_iterator_(heap->map_space()),
+ lo_iterator_(heap->lo_space()) {}
+
+
+Page* Page::next_page() {
+ DCHECK(next_chunk()->owner() == owner());
+ return static_cast<Page*>(next_chunk());
+}
+
+
+Page* Page::prev_page() {
+ DCHECK(prev_chunk()->owner() == owner());
+ return static_cast<Page*>(prev_chunk());
+}
+
+
+void Page::set_next_page(Page* page) {
+ DCHECK(page->owner() == owner());
+ set_next_chunk(page);
+}
+
+
+void Page::set_prev_page(Page* page) {
+ DCHECK(page->owner() == owner());
+ set_prev_chunk(page);
+}
+
+
+// Try linear allocation in the page of alloc_info's allocation top. Does
+// not contain slow case logic (e.g. move to the next page or try free list
+// allocation) so it can be used by all the allocation functions and for all
+// the paged spaces.
+HeapObject* PagedSpace::AllocateLinearly(int size_in_bytes) {
+ Address current_top = allocation_info_.top();
+ Address new_top = current_top + size_in_bytes;
+ if (new_top > allocation_info_.limit()) return NULL;
+
+ allocation_info_.set_top(new_top);
+ return HeapObject::FromAddress(current_top);
+}
+
+
+// Raw allocation.
+AllocationResult PagedSpace::AllocateRaw(int size_in_bytes) {
+ HeapObject* object = AllocateLinearly(size_in_bytes);
+
+ if (object == NULL) {
+ object = free_list_.Allocate(size_in_bytes);
+ if (object == NULL) {
+ object = SlowAllocateRaw(size_in_bytes);
+ }
+ }
+
+ if (object != NULL) {
+ if (identity() == CODE_SPACE) {
+ SkipList::Update(object->address(), size_in_bytes);
+ }
+ MSAN_ALLOCATED_UNINITIALIZED_MEMORY(object->address(), size_in_bytes);
+ return object;
+ }
+
+ return AllocationResult::Retry(identity());
+}
+
+
+// -----------------------------------------------------------------------------
+// NewSpace
+
+
+AllocationResult NewSpace::AllocateRaw(int size_in_bytes) {
+ Address old_top = allocation_info_.top();
+
+ if (allocation_info_.limit() - old_top < size_in_bytes) {
+ return SlowAllocateRaw(size_in_bytes);
+ }
+
+ HeapObject* obj = HeapObject::FromAddress(old_top);
+ allocation_info_.set_top(allocation_info_.top() + size_in_bytes);
+ DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+
+ // The slow path above ultimately goes through AllocateRaw, so this suffices.
+ MSAN_ALLOCATED_UNINITIALIZED_MEMORY(obj->address(), size_in_bytes);
+
+ return obj;
+}
+
+
+LargePage* LargePage::Initialize(Heap* heap, MemoryChunk* chunk) {
+ heap->incremental_marking()->SetOldSpacePageFlags(chunk);
+ return static_cast<LargePage*>(chunk);
+}
+
+
+intptr_t LargeObjectSpace::Available() {
+ return ObjectSizeFor(heap()->isolate()->memory_allocator()->Available());
+}
+
+
+bool FreeListNode::IsFreeListNode(HeapObject* object) {
+ Map* map = object->map();
+ Heap* heap = object->GetHeap();
+ return map == heap->raw_unchecked_free_space_map() ||
+ map == heap->raw_unchecked_one_pointer_filler_map() ||
+ map == heap->raw_unchecked_two_pointer_filler_map();
+}
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_SPACES_INL_H_
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
new file mode 100644
index 0000000..f8d340f
--- /dev/null
+++ b/src/heap/spaces.cc
@@ -0,0 +1,3107 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/v8.h"
+
+#include "src/base/bits.h"
+#include "src/base/platform/platform.h"
+#include "src/full-codegen.h"
+#include "src/heap/mark-compact.h"
+#include "src/macro-assembler.h"
+#include "src/msan.h"
+
+namespace v8 {
+namespace internal {
+
+
+// ----------------------------------------------------------------------------
+// HeapObjectIterator
+
+HeapObjectIterator::HeapObjectIterator(PagedSpace* space) {
+ // You can't actually iterate over the anchor page. It is not a real page,
+ // just an anchor for the double linked page list. Initialize as if we have
+ // reached the end of the anchor page, then the first iteration will move on
+ // to the first page.
+ Initialize(space, NULL, NULL, kAllPagesInSpace, NULL);
+}
+
+
+HeapObjectIterator::HeapObjectIterator(PagedSpace* space,
+ HeapObjectCallback size_func) {
+ // You can't actually iterate over the anchor page. It is not a real page,
+ // just an anchor for the double linked page list. Initialize the current
+ // address and end as NULL, then the first iteration will move on
+ // to the first page.
+ Initialize(space, NULL, NULL, kAllPagesInSpace, size_func);
+}
+
+
+HeapObjectIterator::HeapObjectIterator(Page* page,
+ HeapObjectCallback size_func) {
+ Space* owner = page->owner();
+ DCHECK(owner == page->heap()->old_pointer_space() ||
+ owner == page->heap()->old_data_space() ||
+ owner == page->heap()->map_space() ||
+ owner == page->heap()->cell_space() ||
+ owner == page->heap()->property_cell_space() ||
+ owner == page->heap()->code_space());
+ Initialize(reinterpret_cast<PagedSpace*>(owner), page->area_start(),
+ page->area_end(), kOnePageOnly, size_func);
+ DCHECK(page->WasSwept() || page->SweepingCompleted());
+}
+
+
+void HeapObjectIterator::Initialize(PagedSpace* space, Address cur, Address end,
+ HeapObjectIterator::PageMode mode,
+ HeapObjectCallback size_f) {
+ space_ = space;
+ cur_addr_ = cur;
+ cur_end_ = end;
+ page_mode_ = mode;
+ size_func_ = size_f;
+}
+
+
+// We have hit the end of the page and should advance to the next block of
+// objects. This happens at the end of the page.
+bool HeapObjectIterator::AdvanceToNextPage() {
+ DCHECK(cur_addr_ == cur_end_);
+ if (page_mode_ == kOnePageOnly) return false;
+ Page* cur_page;
+ if (cur_addr_ == NULL) {
+ cur_page = space_->anchor();
+ } else {
+ cur_page = Page::FromAddress(cur_addr_ - 1);
+ DCHECK(cur_addr_ == cur_page->area_end());
+ }
+ cur_page = cur_page->next_page();
+ if (cur_page == space_->anchor()) return false;
+ cur_addr_ = cur_page->area_start();
+ cur_end_ = cur_page->area_end();
+ DCHECK(cur_page->WasSwept() || cur_page->SweepingCompleted());
+ return true;
+}
+
+
+// -----------------------------------------------------------------------------
+// CodeRange
+
+
+CodeRange::CodeRange(Isolate* isolate)
+ : isolate_(isolate),
+ code_range_(NULL),
+ free_list_(0),
+ allocation_list_(0),
+ current_allocation_block_index_(0) {}
+
+
+bool CodeRange::SetUp(size_t requested) {
+ DCHECK(code_range_ == NULL);
+
+ if (requested == 0) {
+ // When a target requires the code range feature, we put all code objects
+ // in a kMaximalCodeRangeSize range of virtual address space, so that
+ // they can call each other with near calls.
+ if (kRequiresCodeRange) {
+ requested = kMaximalCodeRangeSize;
+ } else {
+ return true;
+ }
+ }
+
+ DCHECK(!kRequiresCodeRange || requested <= kMaximalCodeRangeSize);
+ code_range_ = new base::VirtualMemory(requested);
+ CHECK(code_range_ != NULL);
+ if (!code_range_->IsReserved()) {
+ delete code_range_;
+ code_range_ = NULL;
+ return false;
+ }
+
+ // We are sure that we have mapped a block of requested addresses.
+ DCHECK(code_range_->size() == requested);
+ LOG(isolate_, NewEvent("CodeRange", code_range_->address(), requested));
+ Address base = reinterpret_cast<Address>(code_range_->address());
+ Address aligned_base =
+ RoundUp(reinterpret_cast<Address>(code_range_->address()),
+ MemoryChunk::kAlignment);
+ size_t size = code_range_->size() - (aligned_base - base);
+ allocation_list_.Add(FreeBlock(aligned_base, size));
+ current_allocation_block_index_ = 0;
+ return true;
+}
+
+
+int CodeRange::CompareFreeBlockAddress(const FreeBlock* left,
+ const FreeBlock* right) {
+ // The entire point of CodeRange is that the difference between two
+ // addresses in the range can be represented as a signed 32-bit int,
+ // so the cast is semantically correct.
+ return static_cast<int>(left->start - right->start);
+}
+
+
+bool CodeRange::GetNextAllocationBlock(size_t requested) {
+ for (current_allocation_block_index_++;
+ current_allocation_block_index_ < allocation_list_.length();
+ current_allocation_block_index_++) {
+ if (requested <= allocation_list_[current_allocation_block_index_].size) {
+ return true; // Found a large enough allocation block.
+ }
+ }
+
+ // Sort and merge the free blocks on the free list and the allocation list.
+ free_list_.AddAll(allocation_list_);
+ allocation_list_.Clear();
+ free_list_.Sort(&CompareFreeBlockAddress);
+ for (int i = 0; i < free_list_.length();) {
+ FreeBlock merged = free_list_[i];
+ i++;
+ // Add adjacent free blocks to the current merged block.
+ while (i < free_list_.length() &&
+ free_list_[i].start == merged.start + merged.size) {
+ merged.size += free_list_[i].size;
+ i++;
+ }
+ if (merged.size > 0) {
+ allocation_list_.Add(merged);
+ }
+ }
+ free_list_.Clear();
+
+ for (current_allocation_block_index_ = 0;
+ current_allocation_block_index_ < allocation_list_.length();
+ current_allocation_block_index_++) {
+ if (requested <= allocation_list_[current_allocation_block_index_].size) {
+ return true; // Found a large enough allocation block.
+ }
+ }
+ current_allocation_block_index_ = 0;
+ // Code range is full or too fragmented.
+ return false;
+}
+
+
+Address CodeRange::AllocateRawMemory(const size_t requested_size,
+ const size_t commit_size,
+ size_t* allocated) {
+ DCHECK(commit_size <= requested_size);
+ DCHECK(allocation_list_.length() == 0 ||
+ current_allocation_block_index_ < allocation_list_.length());
+ if (allocation_list_.length() == 0 ||
+ requested_size > allocation_list_[current_allocation_block_index_].size) {
+ // Find an allocation block large enough.
+ if (!GetNextAllocationBlock(requested_size)) return NULL;
+ }
+ // Commit the requested memory at the start of the current allocation block.
+ size_t aligned_requested = RoundUp(requested_size, MemoryChunk::kAlignment);
+ FreeBlock current = allocation_list_[current_allocation_block_index_];
+ if (aligned_requested >= (current.size - Page::kPageSize)) {
+ // Don't leave a small free block, useless for a large object or chunk.
+ *allocated = current.size;
+ } else {
+ *allocated = aligned_requested;
+ }
+ DCHECK(*allocated <= current.size);
+ DCHECK(IsAddressAligned(current.start, MemoryChunk::kAlignment));
+ if (!isolate_->memory_allocator()->CommitExecutableMemory(
+ code_range_, current.start, commit_size, *allocated)) {
+ *allocated = 0;
+ return NULL;
+ }
+ allocation_list_[current_allocation_block_index_].start += *allocated;
+ allocation_list_[current_allocation_block_index_].size -= *allocated;
+ if (*allocated == current.size) {
+ // This block is used up, get the next one.
+ GetNextAllocationBlock(0);
+ }
+ return current.start;
+}
+
+
+bool CodeRange::CommitRawMemory(Address start, size_t length) {
+ return isolate_->memory_allocator()->CommitMemory(start, length, EXECUTABLE);
+}
+
+
+bool CodeRange::UncommitRawMemory(Address start, size_t length) {
+ return code_range_->Uncommit(start, length);
+}
+
+
+void CodeRange::FreeRawMemory(Address address, size_t length) {
+ DCHECK(IsAddressAligned(address, MemoryChunk::kAlignment));
+ free_list_.Add(FreeBlock(address, length));
+ code_range_->Uncommit(address, length);
+}
+
+
+void CodeRange::TearDown() {
+ delete code_range_; // Frees all memory in the virtual memory range.
+ code_range_ = NULL;
+ free_list_.Free();
+ allocation_list_.Free();
+}
+
+
+// -----------------------------------------------------------------------------
+// MemoryAllocator
+//
+
+MemoryAllocator::MemoryAllocator(Isolate* isolate)
+ : isolate_(isolate),
+ capacity_(0),
+ capacity_executable_(0),
+ size_(0),
+ size_executable_(0),
+ lowest_ever_allocated_(reinterpret_cast<void*>(-1)),
+ highest_ever_allocated_(reinterpret_cast<void*>(0)) {}
+
+
+bool MemoryAllocator::SetUp(intptr_t capacity, intptr_t capacity_executable) {
+ capacity_ = RoundUp(capacity, Page::kPageSize);
+ capacity_executable_ = RoundUp(capacity_executable, Page::kPageSize);
+ DCHECK_GE(capacity_, capacity_executable_);
+
+ size_ = 0;
+ size_executable_ = 0;
+
+ return true;
+}
+
+
+void MemoryAllocator::TearDown() {
+ // Check that spaces were torn down before MemoryAllocator.
+ DCHECK(size_ == 0);
+ // TODO(gc) this will be true again when we fix FreeMemory.
+ // DCHECK(size_executable_ == 0);
+ capacity_ = 0;
+ capacity_executable_ = 0;
+}
+
+
+bool MemoryAllocator::CommitMemory(Address base, size_t size,
+ Executability executable) {
+ if (!base::VirtualMemory::CommitRegion(base, size,
+ executable == EXECUTABLE)) {
+ return false;
+ }
+ UpdateAllocatedSpaceLimits(base, base + size);
+ return true;
+}
+
+
+void MemoryAllocator::FreeMemory(base::VirtualMemory* reservation,
+ Executability executable) {
+ // TODO(gc) make code_range part of memory allocator?
+ DCHECK(reservation->IsReserved());
+ size_t size = reservation->size();
+ DCHECK(size_ >= size);
+ size_ -= size;
+
+ isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size));
+
+ if (executable == EXECUTABLE) {
+ DCHECK(size_executable_ >= size);
+ size_executable_ -= size;
+ }
+ // Code which is part of the code-range does not have its own VirtualMemory.
+ DCHECK(isolate_->code_range() == NULL ||
+ !isolate_->code_range()->contains(
+ static_cast<Address>(reservation->address())));
+ DCHECK(executable == NOT_EXECUTABLE || isolate_->code_range() == NULL ||
+ !isolate_->code_range()->valid());
+ reservation->Release();
+}
+
+
+void MemoryAllocator::FreeMemory(Address base, size_t size,
+ Executability executable) {
+ // TODO(gc) make code_range part of memory allocator?
+ DCHECK(size_ >= size);
+ size_ -= size;
+
+ isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size));
+
+ if (executable == EXECUTABLE) {
+ DCHECK(size_executable_ >= size);
+ size_executable_ -= size;
+ }
+ if (isolate_->code_range() != NULL &&
+ isolate_->code_range()->contains(static_cast<Address>(base))) {
+ DCHECK(executable == EXECUTABLE);
+ isolate_->code_range()->FreeRawMemory(base, size);
+ } else {
+ DCHECK(executable == NOT_EXECUTABLE || isolate_->code_range() == NULL ||
+ !isolate_->code_range()->valid());
+ bool result = base::VirtualMemory::ReleaseRegion(base, size);
+ USE(result);
+ DCHECK(result);
+ }
+}
+
+
+Address MemoryAllocator::ReserveAlignedMemory(size_t size, size_t alignment,
+ base::VirtualMemory* controller) {
+ base::VirtualMemory reservation(size, alignment);
+
+ if (!reservation.IsReserved()) return NULL;
+ size_ += reservation.size();
+ Address base =
+ RoundUp(static_cast<Address>(reservation.address()), alignment);
+ controller->TakeControl(&reservation);
+ return base;
+}
+
+
+Address MemoryAllocator::AllocateAlignedMemory(
+ size_t reserve_size, size_t commit_size, size_t alignment,
+ Executability executable, base::VirtualMemory* controller) {
+ DCHECK(commit_size <= reserve_size);
+ base::VirtualMemory reservation;
+ Address base = ReserveAlignedMemory(reserve_size, alignment, &reservation);
+ if (base == NULL) return NULL;
+
+ if (executable == EXECUTABLE) {
+ if (!CommitExecutableMemory(&reservation, base, commit_size,
+ reserve_size)) {
+ base = NULL;
+ }
+ } else {
+ if (reservation.Commit(base, commit_size, false)) {
+ UpdateAllocatedSpaceLimits(base, base + commit_size);
+ } else {
+ base = NULL;
+ }
+ }
+
+ if (base == NULL) {
+ // Failed to commit the body. Release the mapping and any partially
+ // commited regions inside it.
+ reservation.Release();
+ return NULL;
+ }
+
+ controller->TakeControl(&reservation);
+ return base;
+}
+
+
+void Page::InitializeAsAnchor(PagedSpace* owner) {
+ set_owner(owner);
+ set_prev_page(this);
+ set_next_page(this);
+}
+
+
+NewSpacePage* NewSpacePage::Initialize(Heap* heap, Address start,
+ SemiSpace* semi_space) {
+ Address area_start = start + NewSpacePage::kObjectStartOffset;
+ Address area_end = start + Page::kPageSize;
+
+ MemoryChunk* chunk =
+ MemoryChunk::Initialize(heap, start, Page::kPageSize, area_start,
+ area_end, NOT_EXECUTABLE, semi_space);
+ chunk->set_next_chunk(NULL);
+ chunk->set_prev_chunk(NULL);
+ chunk->initialize_scan_on_scavenge(true);
+ bool in_to_space = (semi_space->id() != kFromSpace);
+ chunk->SetFlag(in_to_space ? MemoryChunk::IN_TO_SPACE
+ : MemoryChunk::IN_FROM_SPACE);
+ DCHECK(!chunk->IsFlagSet(in_to_space ? MemoryChunk::IN_FROM_SPACE
+ : MemoryChunk::IN_TO_SPACE));
+ NewSpacePage* page = static_cast<NewSpacePage*>(chunk);
+ heap->incremental_marking()->SetNewSpacePageFlags(page);
+ return page;
+}
+
+
+void NewSpacePage::InitializeAsAnchor(SemiSpace* semi_space) {
+ set_owner(semi_space);
+ set_next_chunk(this);
+ set_prev_chunk(this);
+ // Flags marks this invalid page as not being in new-space.
+ // All real new-space pages will be in new-space.
+ SetFlags(0, ~0);
+}
+
+
+MemoryChunk* MemoryChunk::Initialize(Heap* heap, Address base, size_t size,
+ Address area_start, Address area_end,
+ Executability executable, Space* owner) {
+ MemoryChunk* chunk = FromAddress(base);
+
+ DCHECK(base == chunk->address());
+
+ chunk->heap_ = heap;
+ chunk->size_ = size;
+ chunk->area_start_ = area_start;
+ chunk->area_end_ = area_end;
+ chunk->flags_ = 0;
+ chunk->set_owner(owner);
+ chunk->InitializeReservedMemory();
+ chunk->slots_buffer_ = NULL;
+ chunk->skip_list_ = NULL;
+ chunk->write_barrier_counter_ = kWriteBarrierCounterGranularity;
+ chunk->progress_bar_ = 0;
+ chunk->high_water_mark_ = static_cast<int>(area_start - base);
+ chunk->set_parallel_sweeping(SWEEPING_DONE);
+ chunk->available_in_small_free_list_ = 0;
+ chunk->available_in_medium_free_list_ = 0;
+ chunk->available_in_large_free_list_ = 0;
+ chunk->available_in_huge_free_list_ = 0;
+ chunk->non_available_small_blocks_ = 0;
+ chunk->ResetLiveBytes();
+ Bitmap::Clear(chunk);
+ chunk->initialize_scan_on_scavenge(false);
+ chunk->SetFlag(WAS_SWEPT);
+
+ DCHECK(OFFSET_OF(MemoryChunk, flags_) == kFlagsOffset);
+ DCHECK(OFFSET_OF(MemoryChunk, live_byte_count_) == kLiveBytesOffset);
+
+ if (executable == EXECUTABLE) {
+ chunk->SetFlag(IS_EXECUTABLE);
+ }
+
+ if (owner == heap->old_data_space()) {
+ chunk->SetFlag(CONTAINS_ONLY_DATA);
+ }
+
+ return chunk;
+}
+
+
+// Commit MemoryChunk area to the requested size.
+bool MemoryChunk::CommitArea(size_t requested) {
+ size_t guard_size =
+ IsFlagSet(IS_EXECUTABLE) ? MemoryAllocator::CodePageGuardSize() : 0;
+ size_t header_size = area_start() - address() - guard_size;
+ size_t commit_size =
+ RoundUp(header_size + requested, base::OS::CommitPageSize());
+ size_t committed_size = RoundUp(header_size + (area_end() - area_start()),
+ base::OS::CommitPageSize());
+
+ if (commit_size > committed_size) {
+ // Commit size should be less or equal than the reserved size.
+ DCHECK(commit_size <= size() - 2 * guard_size);
+ // Append the committed area.
+ Address start = address() + committed_size + guard_size;
+ size_t length = commit_size - committed_size;
+ if (reservation_.IsReserved()) {
+ Executability executable =
+ IsFlagSet(IS_EXECUTABLE) ? EXECUTABLE : NOT_EXECUTABLE;
+ if (!heap()->isolate()->memory_allocator()->CommitMemory(start, length,
+ executable)) {
+ return false;
+ }
+ } else {
+ CodeRange* code_range = heap_->isolate()->code_range();
+ DCHECK(code_range != NULL && code_range->valid() &&
+ IsFlagSet(IS_EXECUTABLE));
+ if (!code_range->CommitRawMemory(start, length)) return false;
+ }
+
+ if (Heap::ShouldZapGarbage()) {
+ heap_->isolate()->memory_allocator()->ZapBlock(start, length);
+ }
+ } else if (commit_size < committed_size) {
+ DCHECK(commit_size > 0);
+ // Shrink the committed area.
+ size_t length = committed_size - commit_size;
+ Address start = address() + committed_size + guard_size - length;
+ if (reservation_.IsReserved()) {
+ if (!reservation_.Uncommit(start, length)) return false;
+ } else {
+ CodeRange* code_range = heap_->isolate()->code_range();
+ DCHECK(code_range != NULL && code_range->valid() &&
+ IsFlagSet(IS_EXECUTABLE));
+ if (!code_range->UncommitRawMemory(start, length)) return false;
+ }
+ }
+
+ area_end_ = area_start_ + requested;
+ return true;
+}
+
+
+void MemoryChunk::InsertAfter(MemoryChunk* other) {
+ MemoryChunk* other_next = other->next_chunk();
+
+ set_next_chunk(other_next);
+ set_prev_chunk(other);
+ other_next->set_prev_chunk(this);
+ other->set_next_chunk(this);
+}
+
+
+void MemoryChunk::Unlink() {
+ MemoryChunk* next_element = next_chunk();
+ MemoryChunk* prev_element = prev_chunk();
+ next_element->set_prev_chunk(prev_element);
+ prev_element->set_next_chunk(next_element);
+ set_prev_chunk(NULL);
+ set_next_chunk(NULL);
+}
+
+
+MemoryChunk* MemoryAllocator::AllocateChunk(intptr_t reserve_area_size,
+ intptr_t commit_area_size,
+ Executability executable,
+ Space* owner) {
+ DCHECK(commit_area_size <= reserve_area_size);
+
+ size_t chunk_size;
+ Heap* heap = isolate_->heap();
+ Address base = NULL;
+ base::VirtualMemory reservation;
+ Address area_start = NULL;
+ Address area_end = NULL;
+
+ //
+ // MemoryChunk layout:
+ //
+ // Executable
+ // +----------------------------+<- base aligned with MemoryChunk::kAlignment
+ // | Header |
+ // +----------------------------+<- base + CodePageGuardStartOffset
+ // | Guard |
+ // +----------------------------+<- area_start_
+ // | Area |
+ // +----------------------------+<- area_end_ (area_start + commit_area_size)
+ // | Committed but not used |
+ // +----------------------------+<- aligned at OS page boundary
+ // | Reserved but not committed |
+ // +----------------------------+<- aligned at OS page boundary
+ // | Guard |
+ // +----------------------------+<- base + chunk_size
+ //
+ // Non-executable
+ // +----------------------------+<- base aligned with MemoryChunk::kAlignment
+ // | Header |
+ // +----------------------------+<- area_start_ (base + kObjectStartOffset)
+ // | Area |
+ // +----------------------------+<- area_end_ (area_start + commit_area_size)
+ // | Committed but not used |
+ // +----------------------------+<- aligned at OS page boundary
+ // | Reserved but not committed |
+ // +----------------------------+<- base + chunk_size
+ //
+
+ if (executable == EXECUTABLE) {
+ chunk_size = RoundUp(CodePageAreaStartOffset() + reserve_area_size,
+ base::OS::CommitPageSize()) +
+ CodePageGuardSize();
+
+ // Check executable memory limit.
+ if (size_executable_ + chunk_size > capacity_executable_) {
+ LOG(isolate_, StringEvent("MemoryAllocator::AllocateRawMemory",
+ "V8 Executable Allocation capacity exceeded"));
+ return NULL;
+ }
+
+ // Size of header (not executable) plus area (executable).
+ size_t commit_size = RoundUp(CodePageGuardStartOffset() + commit_area_size,
+ base::OS::CommitPageSize());
+ // Allocate executable memory either from code range or from the
+ // OS.
+ if (isolate_->code_range() != NULL && isolate_->code_range()->valid()) {
+ base = isolate_->code_range()->AllocateRawMemory(chunk_size, commit_size,
+ &chunk_size);
+ DCHECK(
+ IsAligned(reinterpret_cast<intptr_t>(base), MemoryChunk::kAlignment));
+ if (base == NULL) return NULL;
+ size_ += chunk_size;
+ // Update executable memory size.
+ size_executable_ += chunk_size;
+ } else {
+ base = AllocateAlignedMemory(chunk_size, commit_size,
+ MemoryChunk::kAlignment, executable,
+ &reservation);
+ if (base == NULL) return NULL;
+ // Update executable memory size.
+ size_executable_ += reservation.size();
+ }
+
+ if (Heap::ShouldZapGarbage()) {
+ ZapBlock(base, CodePageGuardStartOffset());
+ ZapBlock(base + CodePageAreaStartOffset(), commit_area_size);
+ }
+
+ area_start = base + CodePageAreaStartOffset();
+ area_end = area_start + commit_area_size;
+ } else {
+ chunk_size = RoundUp(MemoryChunk::kObjectStartOffset + reserve_area_size,
+ base::OS::CommitPageSize());
+ size_t commit_size =
+ RoundUp(MemoryChunk::kObjectStartOffset + commit_area_size,
+ base::OS::CommitPageSize());
+ base =
+ AllocateAlignedMemory(chunk_size, commit_size, MemoryChunk::kAlignment,
+ executable, &reservation);
+
+ if (base == NULL) return NULL;
+
+ if (Heap::ShouldZapGarbage()) {
+ ZapBlock(base, Page::kObjectStartOffset + commit_area_size);
+ }
+
+ area_start = base + Page::kObjectStartOffset;
+ area_end = area_start + commit_area_size;
+ }
+
+ // Use chunk_size for statistics and callbacks because we assume that they
+ // treat reserved but not-yet committed memory regions of chunks as allocated.
+ isolate_->counters()->memory_allocated()->Increment(
+ static_cast<int>(chunk_size));
+
+ LOG(isolate_, NewEvent("MemoryChunk", base, chunk_size));
+ if (owner != NULL) {
+ ObjectSpace space = static_cast<ObjectSpace>(1 << owner->identity());
+ PerformAllocationCallback(space, kAllocationActionAllocate, chunk_size);
+ }
+
+ MemoryChunk* result = MemoryChunk::Initialize(
+ heap, base, chunk_size, area_start, area_end, executable, owner);
+ result->set_reserved_memory(&reservation);
+ return result;
+}
+
+
+void Page::ResetFreeListStatistics() {
+ non_available_small_blocks_ = 0;
+ available_in_small_free_list_ = 0;
+ available_in_medium_free_list_ = 0;
+ available_in_large_free_list_ = 0;
+ available_in_huge_free_list_ = 0;
+}
+
+
+Page* MemoryAllocator::AllocatePage(intptr_t size, PagedSpace* owner,
+ Executability executable) {
+ MemoryChunk* chunk = AllocateChunk(size, size, executable, owner);
+
+ if (chunk == NULL) return NULL;
+
+ return Page::Initialize(isolate_->heap(), chunk, executable, owner);
+}
+
+
+LargePage* MemoryAllocator::AllocateLargePage(intptr_t object_size,
+ Space* owner,
+ Executability executable) {
+ MemoryChunk* chunk =
+ AllocateChunk(object_size, object_size, executable, owner);
+ if (chunk == NULL) return NULL;
+ return LargePage::Initialize(isolate_->heap(), chunk);
+}
+
+
+void MemoryAllocator::Free(MemoryChunk* chunk) {
+ LOG(isolate_, DeleteEvent("MemoryChunk", chunk));
+ if (chunk->owner() != NULL) {
+ ObjectSpace space =
+ static_cast<ObjectSpace>(1 << chunk->owner()->identity());
+ PerformAllocationCallback(space, kAllocationActionFree, chunk->size());
+ }
+
+ isolate_->heap()->RememberUnmappedPage(reinterpret_cast<Address>(chunk),
+ chunk->IsEvacuationCandidate());
+
+ delete chunk->slots_buffer();
+ delete chunk->skip_list();
+
+ base::VirtualMemory* reservation = chunk->reserved_memory();
+ if (reservation->IsReserved()) {
+ FreeMemory(reservation, chunk->executable());
+ } else {
+ FreeMemory(chunk->address(), chunk->size(), chunk->executable());
+ }
+}
+
+
+bool MemoryAllocator::CommitBlock(Address start, size_t size,
+ Executability executable) {
+ if (!CommitMemory(start, size, executable)) return false;
+
+ if (Heap::ShouldZapGarbage()) {
+ ZapBlock(start, size);
+ }
+
+ isolate_->counters()->memory_allocated()->Increment(static_cast<int>(size));
+ return true;
+}
+
+
+bool MemoryAllocator::UncommitBlock(Address start, size_t size) {
+ if (!base::VirtualMemory::UncommitRegion(start, size)) return false;
+ isolate_->counters()->memory_allocated()->Decrement(static_cast<int>(size));
+ return true;
+}
+
+
+void MemoryAllocator::ZapBlock(Address start, size_t size) {
+ for (size_t s = 0; s + kPointerSize <= size; s += kPointerSize) {
+ Memory::Address_at(start + s) = kZapValue;
+ }
+}
+
+
+void MemoryAllocator::PerformAllocationCallback(ObjectSpace space,
+ AllocationAction action,
+ size_t size) {
+ for (int i = 0; i < memory_allocation_callbacks_.length(); ++i) {
+ MemoryAllocationCallbackRegistration registration =
+ memory_allocation_callbacks_[i];
+ if ((registration.space & space) == space &&
+ (registration.action & action) == action)
+ registration.callback(space, action, static_cast<int>(size));
+ }
+}
+
+
+bool MemoryAllocator::MemoryAllocationCallbackRegistered(
+ MemoryAllocationCallback callback) {
+ for (int i = 0; i < memory_allocation_callbacks_.length(); ++i) {
+ if (memory_allocation_callbacks_[i].callback == callback) return true;
+ }
+ return false;
+}
+
+
+void MemoryAllocator::AddMemoryAllocationCallback(
+ MemoryAllocationCallback callback, ObjectSpace space,
+ AllocationAction action) {
+ DCHECK(callback != NULL);
+ MemoryAllocationCallbackRegistration registration(callback, space, action);
+ DCHECK(!MemoryAllocator::MemoryAllocationCallbackRegistered(callback));
+ return memory_allocation_callbacks_.Add(registration);
+}
+
+
+void MemoryAllocator::RemoveMemoryAllocationCallback(
+ MemoryAllocationCallback callback) {
+ DCHECK(callback != NULL);
+ for (int i = 0; i < memory_allocation_callbacks_.length(); ++i) {
+ if (memory_allocation_callbacks_[i].callback == callback) {
+ memory_allocation_callbacks_.Remove(i);
+ return;
+ }
+ }
+ UNREACHABLE();
+}
+
+
+#ifdef DEBUG
+void MemoryAllocator::ReportStatistics() {
+ float pct = static_cast<float>(capacity_ - size_) / capacity_;
+ PrintF(" capacity: %" V8_PTR_PREFIX
+ "d"
+ ", used: %" V8_PTR_PREFIX
+ "d"
+ ", available: %%%d\n\n",
+ capacity_, size_, static_cast<int>(pct * 100));
+}
+#endif
+
+
+int MemoryAllocator::CodePageGuardStartOffset() {
+ // We are guarding code pages: the first OS page after the header
+ // will be protected as non-writable.
+ return RoundUp(Page::kObjectStartOffset, base::OS::CommitPageSize());
+}
+
+
+int MemoryAllocator::CodePageGuardSize() {
+ return static_cast<int>(base::OS::CommitPageSize());
+}
+
+
+int MemoryAllocator::CodePageAreaStartOffset() {
+ // We are guarding code pages: the first OS page after the header
+ // will be protected as non-writable.
+ return CodePageGuardStartOffset() + CodePageGuardSize();
+}
+
+
+int MemoryAllocator::CodePageAreaEndOffset() {
+ // We are guarding code pages: the last OS page will be protected as
+ // non-writable.
+ return Page::kPageSize - static_cast<int>(base::OS::CommitPageSize());
+}
+
+
+bool MemoryAllocator::CommitExecutableMemory(base::VirtualMemory* vm,
+ Address start, size_t commit_size,
+ size_t reserved_size) {
+ // Commit page header (not executable).
+ if (!vm->Commit(start, CodePageGuardStartOffset(), false)) {
+ return false;
+ }
+
+ // Create guard page after the header.
+ if (!vm->Guard(start + CodePageGuardStartOffset())) {
+ return false;
+ }
+
+ // Commit page body (executable).
+ if (!vm->Commit(start + CodePageAreaStartOffset(),
+ commit_size - CodePageGuardStartOffset(), true)) {
+ return false;
+ }
+
+ // Create guard page before the end.
+ if (!vm->Guard(start + reserved_size - CodePageGuardSize())) {
+ return false;
+ }
+
+ UpdateAllocatedSpaceLimits(start, start + CodePageAreaStartOffset() +
+ commit_size -
+ CodePageGuardStartOffset());
+ return true;
+}
+
+
+// -----------------------------------------------------------------------------
+// MemoryChunk implementation
+
+void MemoryChunk::IncrementLiveBytesFromMutator(Address address, int by) {
+ MemoryChunk* chunk = MemoryChunk::FromAddress(address);
+ if (!chunk->InNewSpace() && !static_cast<Page*>(chunk)->WasSwept()) {
+ static_cast<PagedSpace*>(chunk->owner())->IncrementUnsweptFreeBytes(-by);
+ }
+ chunk->IncrementLiveBytes(by);
+}
+
+
+// -----------------------------------------------------------------------------
+// PagedSpace implementation
+
+PagedSpace::PagedSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id,
+ Executability executable)
+ : Space(heap, id, executable),
+ free_list_(this),
+ unswept_free_bytes_(0),
+ end_of_unswept_pages_(NULL),
+ emergency_memory_(NULL) {
+ if (id == CODE_SPACE) {
+ area_size_ = heap->isolate()->memory_allocator()->CodePageAreaSize();
+ } else {
+ area_size_ = Page::kPageSize - Page::kObjectStartOffset;
+ }
+ max_capacity_ =
+ (RoundDown(max_capacity, Page::kPageSize) / Page::kPageSize) * AreaSize();
+ accounting_stats_.Clear();
+
+ allocation_info_.set_top(NULL);
+ allocation_info_.set_limit(NULL);
+
+ anchor_.InitializeAsAnchor(this);
+}
+
+
+bool PagedSpace::SetUp() { return true; }
+
+
+bool PagedSpace::HasBeenSetUp() { return true; }
+
+
+void PagedSpace::TearDown() {
+ PageIterator iterator(this);
+ while (iterator.has_next()) {
+ heap()->isolate()->memory_allocator()->Free(iterator.next());
+ }
+ anchor_.set_next_page(&anchor_);
+ anchor_.set_prev_page(&anchor_);
+ accounting_stats_.Clear();
+}
+
+
+size_t PagedSpace::CommittedPhysicalMemory() {
+ if (!base::VirtualMemory::HasLazyCommits()) return CommittedMemory();
+ MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
+ size_t size = 0;
+ PageIterator it(this);
+ while (it.has_next()) {
+ size += it.next()->CommittedPhysicalMemory();
+ }
+ return size;
+}
+
+
+Object* PagedSpace::FindObject(Address addr) {
+ // Note: this function can only be called on iterable spaces.
+ DCHECK(!heap()->mark_compact_collector()->in_use());
+
+ if (!Contains(addr)) return Smi::FromInt(0); // Signaling not found.
+
+ Page* p = Page::FromAddress(addr);
+ HeapObjectIterator it(p, NULL);
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ Address cur = obj->address();
+ Address next = cur + obj->Size();
+ if ((cur <= addr) && (addr < next)) return obj;
+ }
+
+ UNREACHABLE();
+ return Smi::FromInt(0);
+}
+
+
+bool PagedSpace::CanExpand() {
+ DCHECK(max_capacity_ % AreaSize() == 0);
+
+ if (Capacity() == max_capacity_) return false;
+
+ DCHECK(Capacity() < max_capacity_);
+
+ // Are we going to exceed capacity for this space?
+ if ((Capacity() + Page::kPageSize) > max_capacity_) return false;
+
+ return true;
+}
+
+
+bool PagedSpace::Expand() {
+ if (!CanExpand()) return false;
+
+ intptr_t size = AreaSize();
+
+ if (anchor_.next_page() == &anchor_) {
+ size = SizeOfFirstPage();
+ }
+
+ Page* p = heap()->isolate()->memory_allocator()->AllocatePage(size, this,
+ executable());
+ if (p == NULL) return false;
+
+ DCHECK(Capacity() <= max_capacity_);
+
+ p->InsertAfter(anchor_.prev_page());
+
+ return true;
+}
+
+
+intptr_t PagedSpace::SizeOfFirstPage() {
+ // If using an ool constant pool then transfer the constant pool allowance
+ // from the code space to the old pointer space.
+ static const int constant_pool_delta = FLAG_enable_ool_constant_pool ? 48 : 0;
+ int size = 0;
+ switch (identity()) {
+ case OLD_POINTER_SPACE:
+ size = (112 + constant_pool_delta) * kPointerSize * KB;
+ break;
+ case OLD_DATA_SPACE:
+ size = 192 * KB;
+ break;
+ case MAP_SPACE:
+ size = 16 * kPointerSize * KB;
+ break;
+ case CELL_SPACE:
+ size = 16 * kPointerSize * KB;
+ break;
+ case PROPERTY_CELL_SPACE:
+ size = 8 * kPointerSize * KB;
+ break;
+ case CODE_SPACE: {
+ CodeRange* code_range = heap()->isolate()->code_range();
+ if (code_range != NULL && code_range->valid()) {
+ // When code range exists, code pages are allocated in a special way
+ // (from the reserved code range). That part of the code is not yet
+ // upgraded to handle small pages.
+ size = AreaSize();
+ } else {
+ size = RoundUp((480 - constant_pool_delta) * KB *
+ FullCodeGenerator::kBootCodeSizeMultiplier / 100,
+ kPointerSize);
+ }
+ break;
+ }
+ default:
+ UNREACHABLE();
+ }
+ return Min(size, AreaSize());
+}
+
+
+int PagedSpace::CountTotalPages() {
+ PageIterator it(this);
+ int count = 0;
+ while (it.has_next()) {
+ it.next();
+ count++;
+ }
+ return count;
+}
+
+
+void PagedSpace::ObtainFreeListStatistics(Page* page, SizeStats* sizes) {
+ sizes->huge_size_ = page->available_in_huge_free_list();
+ sizes->small_size_ = page->available_in_small_free_list();
+ sizes->medium_size_ = page->available_in_medium_free_list();
+ sizes->large_size_ = page->available_in_large_free_list();
+}
+
+
+void PagedSpace::ResetFreeListStatistics() {
+ PageIterator page_iterator(this);
+ while (page_iterator.has_next()) {
+ Page* page = page_iterator.next();
+ page->ResetFreeListStatistics();
+ }
+}
+
+
+void PagedSpace::IncreaseCapacity(int size) {
+ accounting_stats_.ExpandSpace(size);
+}
+
+
+void PagedSpace::ReleasePage(Page* page) {
+ DCHECK(page->LiveBytes() == 0);
+ DCHECK(AreaSize() == page->area_size());
+
+ if (page->WasSwept()) {
+ intptr_t size = free_list_.EvictFreeListItems(page);
+ accounting_stats_.AllocateBytes(size);
+ DCHECK_EQ(AreaSize(), static_cast<int>(size));
+ } else {
+ DecreaseUnsweptFreeBytes(page);
+ }
+
+ if (page->IsFlagSet(MemoryChunk::SCAN_ON_SCAVENGE)) {
+ heap()->decrement_scan_on_scavenge_pages();
+ page->ClearFlag(MemoryChunk::SCAN_ON_SCAVENGE);
+ }
+
+ DCHECK(!free_list_.ContainsPageFreeListItems(page));
+
+ if (Page::FromAllocationTop(allocation_info_.top()) == page) {
+ allocation_info_.set_top(NULL);
+ allocation_info_.set_limit(NULL);
+ }
+
+ page->Unlink();
+ if (page->IsFlagSet(MemoryChunk::CONTAINS_ONLY_DATA)) {
+ heap()->isolate()->memory_allocator()->Free(page);
+ } else {
+ heap()->QueueMemoryChunkForFree(page);
+ }
+
+ DCHECK(Capacity() > 0);
+ accounting_stats_.ShrinkSpace(AreaSize());
+}
+
+
+void PagedSpace::CreateEmergencyMemory() {
+ emergency_memory_ = heap()->isolate()->memory_allocator()->AllocateChunk(
+ AreaSize(), AreaSize(), executable(), this);
+}
+
+
+void PagedSpace::FreeEmergencyMemory() {
+ Page* page = static_cast<Page*>(emergency_memory_);
+ DCHECK(page->LiveBytes() == 0);
+ DCHECK(AreaSize() == page->area_size());
+ DCHECK(!free_list_.ContainsPageFreeListItems(page));
+ heap()->isolate()->memory_allocator()->Free(page);
+ emergency_memory_ = NULL;
+}
+
+
+void PagedSpace::UseEmergencyMemory() {
+ Page* page = Page::Initialize(heap(), emergency_memory_, executable(), this);
+ page->InsertAfter(anchor_.prev_page());
+ emergency_memory_ = NULL;
+}
+
+
+#ifdef DEBUG
+void PagedSpace::Print() {}
+#endif
+
+#ifdef VERIFY_HEAP
+void PagedSpace::Verify(ObjectVisitor* visitor) {
+ bool allocation_pointer_found_in_space =
+ (allocation_info_.top() == allocation_info_.limit());
+ PageIterator page_iterator(this);
+ while (page_iterator.has_next()) {
+ Page* page = page_iterator.next();
+ CHECK(page->owner() == this);
+ if (page == Page::FromAllocationTop(allocation_info_.top())) {
+ allocation_pointer_found_in_space = true;
+ }
+ CHECK(page->WasSwept());
+ HeapObjectIterator it(page, NULL);
+ Address end_of_previous_object = page->area_start();
+ Address top = page->area_end();
+ int black_size = 0;
+ for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) {
+ CHECK(end_of_previous_object <= object->address());
+
+ // The first word should be a map, and we expect all map pointers to
+ // be in map space.
+ Map* map = object->map();
+ CHECK(map->IsMap());
+ CHECK(heap()->map_space()->Contains(map));
+
+ // Perform space-specific object verification.
+ VerifyObject(object);
+
+ // The object itself should look OK.
+ object->ObjectVerify();
+
+ // All the interior pointers should be contained in the heap.
+ int size = object->Size();
+ object->IterateBody(map->instance_type(), size, visitor);
+ if (Marking::IsBlack(Marking::MarkBitFrom(object))) {
+ black_size += size;
+ }
+
+ CHECK(object->address() + size <= top);
+ end_of_previous_object = object->address() + size;
+ }
+ CHECK_LE(black_size, page->LiveBytes());
+ }
+ CHECK(allocation_pointer_found_in_space);
+}
+#endif // VERIFY_HEAP
+
+// -----------------------------------------------------------------------------
+// NewSpace implementation
+
+
+bool NewSpace::SetUp(int reserved_semispace_capacity,
+ int maximum_semispace_capacity) {
+ // Set up new space based on the preallocated memory block defined by
+ // start and size. The provided space is divided into two semi-spaces.
+ // To support fast containment testing in the new space, the size of
+ // this chunk must be a power of two and it must be aligned to its size.
+ int initial_semispace_capacity = heap()->InitialSemiSpaceSize();
+
+ size_t size = 2 * reserved_semispace_capacity;
+ Address base = heap()->isolate()->memory_allocator()->ReserveAlignedMemory(
+ size, size, &reservation_);
+ if (base == NULL) return false;
+
+ chunk_base_ = base;
+ chunk_size_ = static_cast<uintptr_t>(size);
+ LOG(heap()->isolate(), NewEvent("InitialChunk", chunk_base_, chunk_size_));
+
+ DCHECK(initial_semispace_capacity <= maximum_semispace_capacity);
+ DCHECK(base::bits::IsPowerOfTwo32(maximum_semispace_capacity));
+
+ // Allocate and set up the histogram arrays if necessary.
+ allocated_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
+ promoted_histogram_ = NewArray<HistogramInfo>(LAST_TYPE + 1);
+
+#define SET_NAME(name) \
+ allocated_histogram_[name].set_name(#name); \
+ promoted_histogram_[name].set_name(#name);
+ INSTANCE_TYPE_LIST(SET_NAME)
+#undef SET_NAME
+
+ DCHECK(reserved_semispace_capacity == heap()->ReservedSemiSpaceSize());
+ DCHECK(static_cast<intptr_t>(chunk_size_) >=
+ 2 * heap()->ReservedSemiSpaceSize());
+ DCHECK(IsAddressAligned(chunk_base_, 2 * reserved_semispace_capacity, 0));
+
+ to_space_.SetUp(chunk_base_, initial_semispace_capacity,
+ maximum_semispace_capacity);
+ from_space_.SetUp(chunk_base_ + reserved_semispace_capacity,
+ initial_semispace_capacity, maximum_semispace_capacity);
+ if (!to_space_.Commit()) {
+ return false;
+ }
+ DCHECK(!from_space_.is_committed()); // No need to use memory yet.
+
+ start_ = chunk_base_;
+ address_mask_ = ~(2 * reserved_semispace_capacity - 1);
+ object_mask_ = address_mask_ | kHeapObjectTagMask;
+ object_expected_ = reinterpret_cast<uintptr_t>(start_) | kHeapObjectTag;
+
+ ResetAllocationInfo();
+
+ return true;
+}
+
+
+void NewSpace::TearDown() {
+ if (allocated_histogram_) {
+ DeleteArray(allocated_histogram_);
+ allocated_histogram_ = NULL;
+ }
+ if (promoted_histogram_) {
+ DeleteArray(promoted_histogram_);
+ promoted_histogram_ = NULL;
+ }
+
+ start_ = NULL;
+ allocation_info_.set_top(NULL);
+ allocation_info_.set_limit(NULL);
+
+ to_space_.TearDown();
+ from_space_.TearDown();
+
+ LOG(heap()->isolate(), DeleteEvent("InitialChunk", chunk_base_));
+
+ DCHECK(reservation_.IsReserved());
+ heap()->isolate()->memory_allocator()->FreeMemory(&reservation_,
+ NOT_EXECUTABLE);
+ chunk_base_ = NULL;
+ chunk_size_ = 0;
+}
+
+
+void NewSpace::Flip() { SemiSpace::Swap(&from_space_, &to_space_); }
+
+
+void NewSpace::Grow() {
+ // Double the semispace size but only up to maximum capacity.
+ DCHECK(TotalCapacity() < MaximumCapacity());
+ int new_capacity =
+ Min(MaximumCapacity(), 2 * static_cast<int>(TotalCapacity()));
+ if (to_space_.GrowTo(new_capacity)) {
+ // Only grow from space if we managed to grow to-space.
+ if (!from_space_.GrowTo(new_capacity)) {
+ // If we managed to grow to-space but couldn't grow from-space,
+ // attempt to shrink to-space.
+ if (!to_space_.ShrinkTo(from_space_.TotalCapacity())) {
+ // We are in an inconsistent state because we could not
+ // commit/uncommit memory from new space.
+ V8::FatalProcessOutOfMemory("Failed to grow new space.");
+ }
+ }
+ }
+ DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+}
+
+
+void NewSpace::Shrink() {
+ int new_capacity = Max(InitialTotalCapacity(), 2 * SizeAsInt());
+ int rounded_new_capacity = RoundUp(new_capacity, Page::kPageSize);
+ if (rounded_new_capacity < TotalCapacity() &&
+ to_space_.ShrinkTo(rounded_new_capacity)) {
+ // Only shrink from-space if we managed to shrink to-space.
+ from_space_.Reset();
+ if (!from_space_.ShrinkTo(rounded_new_capacity)) {
+ // If we managed to shrink to-space but couldn't shrink from
+ // space, attempt to grow to-space again.
+ if (!to_space_.GrowTo(from_space_.TotalCapacity())) {
+ // We are in an inconsistent state because we could not
+ // commit/uncommit memory from new space.
+ V8::FatalProcessOutOfMemory("Failed to shrink new space.");
+ }
+ }
+ }
+ DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+}
+
+
+void NewSpace::UpdateAllocationInfo() {
+ MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
+ allocation_info_.set_top(to_space_.page_low());
+ allocation_info_.set_limit(to_space_.page_high());
+ UpdateInlineAllocationLimit(0);
+ DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+}
+
+
+void NewSpace::ResetAllocationInfo() {
+ to_space_.Reset();
+ UpdateAllocationInfo();
+ pages_used_ = 0;
+ // Clear all mark-bits in the to-space.
+ NewSpacePageIterator it(&to_space_);
+ while (it.has_next()) {
+ Bitmap::Clear(it.next());
+ }
+}
+
+
+void NewSpace::UpdateInlineAllocationLimit(int size_in_bytes) {
+ if (heap()->inline_allocation_disabled()) {
+ // Lowest limit when linear allocation was disabled.
+ Address high = to_space_.page_high();
+ Address new_top = allocation_info_.top() + size_in_bytes;
+ allocation_info_.set_limit(Min(new_top, high));
+ } else if (inline_allocation_limit_step() == 0) {
+ // Normal limit is the end of the current page.
+ allocation_info_.set_limit(to_space_.page_high());
+ } else {
+ // Lower limit during incremental marking.
+ Address high = to_space_.page_high();
+ Address new_top = allocation_info_.top() + size_in_bytes;
+ Address new_limit = new_top + inline_allocation_limit_step_;
+ allocation_info_.set_limit(Min(new_limit, high));
+ }
+ DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+}
+
+
+bool NewSpace::AddFreshPage() {
+ Address top = allocation_info_.top();
+ if (NewSpacePage::IsAtStart(top)) {
+ // The current page is already empty. Don't try to make another.
+
+ // We should only get here if someone asks to allocate more
+ // than what can be stored in a single page.
+ // TODO(gc): Change the limit on new-space allocation to prevent this
+ // from happening (all such allocations should go directly to LOSpace).
+ return false;
+ }
+ if (!to_space_.AdvancePage()) {
+ // Failed to get a new page in to-space.
+ return false;
+ }
+
+ // Clear remainder of current page.
+ Address limit = NewSpacePage::FromLimit(top)->area_end();
+ if (heap()->gc_state() == Heap::SCAVENGE) {
+ heap()->promotion_queue()->SetNewLimit(limit);
+ }
+
+ int remaining_in_page = static_cast<int>(limit - top);
+ heap()->CreateFillerObjectAt(top, remaining_in_page);
+ pages_used_++;
+ UpdateAllocationInfo();
+
+ return true;
+}
+
+
+AllocationResult NewSpace::SlowAllocateRaw(int size_in_bytes) {
+ Address old_top = allocation_info_.top();
+ Address high = to_space_.page_high();
+ if (allocation_info_.limit() < high) {
+ // Either the limit has been lowered because linear allocation was disabled
+ // or because incremental marking wants to get a chance to do a step. Set
+ // the new limit accordingly.
+ Address new_top = old_top + size_in_bytes;
+ int bytes_allocated = static_cast<int>(new_top - top_on_previous_step_);
+ heap()->incremental_marking()->Step(bytes_allocated,
+ IncrementalMarking::GC_VIA_STACK_GUARD);
+ UpdateInlineAllocationLimit(size_in_bytes);
+ top_on_previous_step_ = new_top;
+ return AllocateRaw(size_in_bytes);
+ } else if (AddFreshPage()) {
+ // Switched to new page. Try allocating again.
+ int bytes_allocated = static_cast<int>(old_top - top_on_previous_step_);
+ heap()->incremental_marking()->Step(bytes_allocated,
+ IncrementalMarking::GC_VIA_STACK_GUARD);
+ top_on_previous_step_ = to_space_.page_low();
+ return AllocateRaw(size_in_bytes);
+ } else {
+ return AllocationResult::Retry();
+ }
+}
+
+
+#ifdef VERIFY_HEAP
+// We do not use the SemiSpaceIterator because verification doesn't assume
+// that it works (it depends on the invariants we are checking).
+void NewSpace::Verify() {
+ // The allocation pointer should be in the space or at the very end.
+ DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
+
+ // There should be objects packed in from the low address up to the
+ // allocation pointer.
+ Address current = to_space_.first_page()->area_start();
+ CHECK_EQ(current, to_space_.space_start());
+
+ while (current != top()) {
+ if (!NewSpacePage::IsAtEnd(current)) {
+ // The allocation pointer should not be in the middle of an object.
+ CHECK(!NewSpacePage::FromLimit(current)->ContainsLimit(top()) ||
+ current < top());
+
+ HeapObject* object = HeapObject::FromAddress(current);
+
+ // The first word should be a map, and we expect all map pointers to
+ // be in map space.
+ Map* map = object->map();
+ CHECK(map->IsMap());
+ CHECK(heap()->map_space()->Contains(map));
+
+ // The object should not be code or a map.
+ CHECK(!object->IsMap());
+ CHECK(!object->IsCode());
+
+ // The object itself should look OK.
+ object->ObjectVerify();
+
+ // All the interior pointers should be contained in the heap.
+ VerifyPointersVisitor visitor;
+ int size = object->Size();
+ object->IterateBody(map->instance_type(), size, &visitor);
+
+ current += size;
+ } else {
+ // At end of page, switch to next page.
+ NewSpacePage* page = NewSpacePage::FromLimit(current)->next_page();
+ // Next page should be valid.
+ CHECK(!page->is_anchor());
+ current = page->area_start();
+ }
+ }
+
+ // Check semi-spaces.
+ CHECK_EQ(from_space_.id(), kFromSpace);
+ CHECK_EQ(to_space_.id(), kToSpace);
+ from_space_.Verify();
+ to_space_.Verify();
+}
+#endif
+
+// -----------------------------------------------------------------------------
+// SemiSpace implementation
+
+void SemiSpace::SetUp(Address start, int initial_capacity,
+ int maximum_capacity) {
+ // Creates a space in the young generation. The constructor does not
+ // allocate memory from the OS. A SemiSpace is given a contiguous chunk of
+ // memory of size 'capacity' when set up, and does not grow or shrink
+ // otherwise. In the mark-compact collector, the memory region of the from
+ // space is used as the marking stack. It requires contiguous memory
+ // addresses.
+ DCHECK(maximum_capacity >= Page::kPageSize);
+ initial_total_capacity_ = RoundDown(initial_capacity, Page::kPageSize);
+ total_capacity_ = initial_capacity;
+ maximum_total_capacity_ = RoundDown(maximum_capacity, Page::kPageSize);
+ maximum_committed_ = 0;
+ committed_ = false;
+ start_ = start;
+ address_mask_ = ~(maximum_capacity - 1);
+ object_mask_ = address_mask_ | kHeapObjectTagMask;
+ object_expected_ = reinterpret_cast<uintptr_t>(start) | kHeapObjectTag;
+ age_mark_ = start_;
+}
+
+
+void SemiSpace::TearDown() {
+ start_ = NULL;
+ total_capacity_ = 0;
+}
+
+
+bool SemiSpace::Commit() {
+ DCHECK(!is_committed());
+ int pages = total_capacity_ / Page::kPageSize;
+ if (!heap()->isolate()->memory_allocator()->CommitBlock(
+ start_, total_capacity_, executable())) {
+ return false;
+ }
+
+ NewSpacePage* current = anchor();
+ for (int i = 0; i < pages; i++) {
+ NewSpacePage* new_page =
+ NewSpacePage::Initialize(heap(), start_ + i * Page::kPageSize, this);
+ new_page->InsertAfter(current);
+ current = new_page;
+ }
+
+ SetCapacity(total_capacity_);
+ committed_ = true;
+ Reset();
+ return true;
+}
+
+
+bool SemiSpace::Uncommit() {
+ DCHECK(is_committed());
+ Address start = start_ + maximum_total_capacity_ - total_capacity_;
+ if (!heap()->isolate()->memory_allocator()->UncommitBlock(start,
+ total_capacity_)) {
+ return false;
+ }
+ anchor()->set_next_page(anchor());
+ anchor()->set_prev_page(anchor());
+
+ committed_ = false;
+ return true;
+}
+
+
+size_t SemiSpace::CommittedPhysicalMemory() {
+ if (!is_committed()) return 0;
+ size_t size = 0;
+ NewSpacePageIterator it(this);
+ while (it.has_next()) {
+ size += it.next()->CommittedPhysicalMemory();
+ }
+ return size;
+}
+
+
+bool SemiSpace::GrowTo(int new_capacity) {
+ if (!is_committed()) {
+ if (!Commit()) return false;
+ }
+ DCHECK((new_capacity & Page::kPageAlignmentMask) == 0);
+ DCHECK(new_capacity <= maximum_total_capacity_);
+ DCHECK(new_capacity > total_capacity_);
+ int pages_before = total_capacity_ / Page::kPageSize;
+ int pages_after = new_capacity / Page::kPageSize;
+
+ size_t delta = new_capacity - total_capacity_;
+
+ DCHECK(IsAligned(delta, base::OS::AllocateAlignment()));
+ if (!heap()->isolate()->memory_allocator()->CommitBlock(
+ start_ + total_capacity_, delta, executable())) {
+ return false;
+ }
+ SetCapacity(new_capacity);
+ NewSpacePage* last_page = anchor()->prev_page();
+ DCHECK(last_page != anchor());
+ for (int i = pages_before; i < pages_after; i++) {
+ Address page_address = start_ + i * Page::kPageSize;
+ NewSpacePage* new_page =
+ NewSpacePage::Initialize(heap(), page_address, this);
+ new_page->InsertAfter(last_page);
+ Bitmap::Clear(new_page);
+ // Duplicate the flags that was set on the old page.
+ new_page->SetFlags(last_page->GetFlags(),
+ NewSpacePage::kCopyOnFlipFlagsMask);
+ last_page = new_page;
+ }
+ return true;
+}
+
+
+bool SemiSpace::ShrinkTo(int new_capacity) {
+ DCHECK((new_capacity & Page::kPageAlignmentMask) == 0);
+ DCHECK(new_capacity >= initial_total_capacity_);
+ DCHECK(new_capacity < total_capacity_);
+ if (is_committed()) {
+ size_t delta = total_capacity_ - new_capacity;
+ DCHECK(IsAligned(delta, base::OS::AllocateAlignment()));
+
+ MemoryAllocator* allocator = heap()->isolate()->memory_allocator();
+ if (!allocator->UncommitBlock(start_ + new_capacity, delta)) {
+ return false;
+ }
+
+ int pages_after = new_capacity / Page::kPageSize;
+ NewSpacePage* new_last_page =
+ NewSpacePage::FromAddress(start_ + (pages_after - 1) * Page::kPageSize);
+ new_last_page->set_next_page(anchor());
+ anchor()->set_prev_page(new_last_page);
+ DCHECK((current_page_ >= first_page()) && (current_page_ <= new_last_page));
+ }
+
+ SetCapacity(new_capacity);
+
+ return true;
+}
+
+
+void SemiSpace::FlipPages(intptr_t flags, intptr_t mask) {
+ anchor_.set_owner(this);
+ // Fixup back-pointers to anchor. Address of anchor changes
+ // when we swap.
+ anchor_.prev_page()->set_next_page(&anchor_);
+ anchor_.next_page()->set_prev_page(&anchor_);
+
+ bool becomes_to_space = (id_ == kFromSpace);
+ id_ = becomes_to_space ? kToSpace : kFromSpace;
+ NewSpacePage* page = anchor_.next_page();
+ while (page != &anchor_) {
+ page->set_owner(this);
+ page->SetFlags(flags, mask);
+ if (becomes_to_space) {
+ page->ClearFlag(MemoryChunk::IN_FROM_SPACE);
+ page->SetFlag(MemoryChunk::IN_TO_SPACE);
+ page->ClearFlag(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK);
+ page->ResetLiveBytes();
+ } else {
+ page->SetFlag(MemoryChunk::IN_FROM_SPACE);
+ page->ClearFlag(MemoryChunk::IN_TO_SPACE);
+ }
+ DCHECK(page->IsFlagSet(MemoryChunk::SCAN_ON_SCAVENGE));
+ DCHECK(page->IsFlagSet(MemoryChunk::IN_TO_SPACE) ||
+ page->IsFlagSet(MemoryChunk::IN_FROM_SPACE));
+ page = page->next_page();
+ }
+}
+
+
+void SemiSpace::Reset() {
+ DCHECK(anchor_.next_page() != &anchor_);
+ current_page_ = anchor_.next_page();
+}
+
+
+void SemiSpace::Swap(SemiSpace* from, SemiSpace* to) {
+ // We won't be swapping semispaces without data in them.
+ DCHECK(from->anchor_.next_page() != &from->anchor_);
+ DCHECK(to->anchor_.next_page() != &to->anchor_);
+
+ // Swap bits.
+ SemiSpace tmp = *from;
+ *from = *to;
+ *to = tmp;
+
+ // Fixup back-pointers to the page list anchor now that its address
+ // has changed.
+ // Swap to/from-space bits on pages.
+ // Copy GC flags from old active space (from-space) to new (to-space).
+ intptr_t flags = from->current_page()->GetFlags();
+ to->FlipPages(flags, NewSpacePage::kCopyOnFlipFlagsMask);
+
+ from->FlipPages(0, 0);
+}
+
+
+void SemiSpace::SetCapacity(int new_capacity) {
+ total_capacity_ = new_capacity;
+ if (total_capacity_ > maximum_committed_) {
+ maximum_committed_ = total_capacity_;
+ }
+}
+
+
+void SemiSpace::set_age_mark(Address mark) {
+ DCHECK(NewSpacePage::FromLimit(mark)->semi_space() == this);
+ age_mark_ = mark;
+ // Mark all pages up to the one containing mark.
+ NewSpacePageIterator it(space_start(), mark);
+ while (it.has_next()) {
+ it.next()->SetFlag(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK);
+ }
+}
+
+
+#ifdef DEBUG
+void SemiSpace::Print() {}
+#endif
+
+#ifdef VERIFY_HEAP
+void SemiSpace::Verify() {
+ bool is_from_space = (id_ == kFromSpace);
+ NewSpacePage* page = anchor_.next_page();
+ CHECK(anchor_.semi_space() == this);
+ while (page != &anchor_) {
+ CHECK(page->semi_space() == this);
+ CHECK(page->InNewSpace());
+ CHECK(page->IsFlagSet(is_from_space ? MemoryChunk::IN_FROM_SPACE
+ : MemoryChunk::IN_TO_SPACE));
+ CHECK(!page->IsFlagSet(is_from_space ? MemoryChunk::IN_TO_SPACE
+ : MemoryChunk::IN_FROM_SPACE));
+ CHECK(page->IsFlagSet(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING));
+ if (!is_from_space) {
+ // The pointers-from-here-are-interesting flag isn't updated dynamically
+ // on from-space pages, so it might be out of sync with the marking state.
+ if (page->heap()->incremental_marking()->IsMarking()) {
+ CHECK(page->IsFlagSet(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING));
+ } else {
+ CHECK(
+ !page->IsFlagSet(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING));
+ }
+ // TODO(gc): Check that the live_bytes_count_ field matches the
+ // black marking on the page (if we make it match in new-space).
+ }
+ CHECK(page->IsFlagSet(MemoryChunk::SCAN_ON_SCAVENGE));
+ CHECK(page->prev_page()->next_page() == page);
+ page = page->next_page();
+ }
+}
+#endif
+
+#ifdef DEBUG
+void SemiSpace::AssertValidRange(Address start, Address end) {
+ // Addresses belong to same semi-space
+ NewSpacePage* page = NewSpacePage::FromLimit(start);
+ NewSpacePage* end_page = NewSpacePage::FromLimit(end);
+ SemiSpace* space = page->semi_space();
+ CHECK_EQ(space, end_page->semi_space());
+ // Start address is before end address, either on same page,
+ // or end address is on a later page in the linked list of
+ // semi-space pages.
+ if (page == end_page) {
+ CHECK(start <= end);
+ } else {
+ while (page != end_page) {
+ page = page->next_page();
+ CHECK_NE(page, space->anchor());
+ }
+ }
+}
+#endif
+
+
+// -----------------------------------------------------------------------------
+// SemiSpaceIterator implementation.
+SemiSpaceIterator::SemiSpaceIterator(NewSpace* space) {
+ Initialize(space->bottom(), space->top(), NULL);
+}
+
+
+SemiSpaceIterator::SemiSpaceIterator(NewSpace* space,
+ HeapObjectCallback size_func) {
+ Initialize(space->bottom(), space->top(), size_func);
+}
+
+
+SemiSpaceIterator::SemiSpaceIterator(NewSpace* space, Address start) {
+ Initialize(start, space->top(), NULL);
+}
+
+
+SemiSpaceIterator::SemiSpaceIterator(Address from, Address to) {
+ Initialize(from, to, NULL);
+}
+
+
+void SemiSpaceIterator::Initialize(Address start, Address end,
+ HeapObjectCallback size_func) {
+ SemiSpace::AssertValidRange(start, end);
+ current_ = start;
+ limit_ = end;
+ size_func_ = size_func;
+}
+
+
+#ifdef DEBUG
+// heap_histograms is shared, always clear it before using it.
+static void ClearHistograms(Isolate* isolate) {
+// We reset the name each time, though it hasn't changed.
+#define DEF_TYPE_NAME(name) isolate->heap_histograms()[name].set_name(#name);
+ INSTANCE_TYPE_LIST(DEF_TYPE_NAME)
+#undef DEF_TYPE_NAME
+
+#define CLEAR_HISTOGRAM(name) isolate->heap_histograms()[name].clear();
+ INSTANCE_TYPE_LIST(CLEAR_HISTOGRAM)
+#undef CLEAR_HISTOGRAM
+
+ isolate->js_spill_information()->Clear();
+}
+
+
+static void ClearCodeKindStatistics(int* code_kind_statistics) {
+ for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) {
+ code_kind_statistics[i] = 0;
+ }
+}
+
+
+static void ReportCodeKindStatistics(int* code_kind_statistics) {
+ PrintF("\n Code kind histograms: \n");
+ for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) {
+ if (code_kind_statistics[i] > 0) {
+ PrintF(" %-20s: %10d bytes\n",
+ Code::Kind2String(static_cast<Code::Kind>(i)),
+ code_kind_statistics[i]);
+ }
+ }
+ PrintF("\n");
+}
+
+
+static int CollectHistogramInfo(HeapObject* obj) {
+ Isolate* isolate = obj->GetIsolate();
+ InstanceType type = obj->map()->instance_type();
+ DCHECK(0 <= type && type <= LAST_TYPE);
+ DCHECK(isolate->heap_histograms()[type].name() != NULL);
+ isolate->heap_histograms()[type].increment_number(1);
+ isolate->heap_histograms()[type].increment_bytes(obj->Size());
+
+ if (FLAG_collect_heap_spill_statistics && obj->IsJSObject()) {
+ JSObject::cast(obj)
+ ->IncrementSpillStatistics(isolate->js_spill_information());
+ }
+
+ return obj->Size();
+}
+
+
+static void ReportHistogram(Isolate* isolate, bool print_spill) {
+ PrintF("\n Object Histogram:\n");
+ for (int i = 0; i <= LAST_TYPE; i++) {
+ if (isolate->heap_histograms()[i].number() > 0) {
+ PrintF(" %-34s%10d (%10d bytes)\n",
+ isolate->heap_histograms()[i].name(),
+ isolate->heap_histograms()[i].number(),
+ isolate->heap_histograms()[i].bytes());
+ }
+ }
+ PrintF("\n");
+
+ // Summarize string types.
+ int string_number = 0;
+ int string_bytes = 0;
+#define INCREMENT(type, size, name, camel_name) \
+ string_number += isolate->heap_histograms()[type].number(); \
+ string_bytes += isolate->heap_histograms()[type].bytes();
+ STRING_TYPE_LIST(INCREMENT)
+#undef INCREMENT
+ if (string_number > 0) {
+ PrintF(" %-34s%10d (%10d bytes)\n\n", "STRING_TYPE", string_number,
+ string_bytes);
+ }
+
+ if (FLAG_collect_heap_spill_statistics && print_spill) {
+ isolate->js_spill_information()->Print();
+ }
+}
+#endif // DEBUG
+
+
+// Support for statistics gathering for --heap-stats and --log-gc.
+void NewSpace::ClearHistograms() {
+ for (int i = 0; i <= LAST_TYPE; i++) {
+ allocated_histogram_[i].clear();
+ promoted_histogram_[i].clear();
+ }
+}
+
+
+// Because the copying collector does not touch garbage objects, we iterate
+// the new space before a collection to get a histogram of allocated objects.
+// This only happens when --log-gc flag is set.
+void NewSpace::CollectStatistics() {
+ ClearHistograms();
+ SemiSpaceIterator it(this);
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next())
+ RecordAllocation(obj);
+}
+
+
+static void DoReportStatistics(Isolate* isolate, HistogramInfo* info,
+ const char* description) {
+ LOG(isolate, HeapSampleBeginEvent("NewSpace", description));
+ // Lump all the string types together.
+ int string_number = 0;
+ int string_bytes = 0;
+#define INCREMENT(type, size, name, camel_name) \
+ string_number += info[type].number(); \
+ string_bytes += info[type].bytes();
+ STRING_TYPE_LIST(INCREMENT)
+#undef INCREMENT
+ if (string_number > 0) {
+ LOG(isolate,
+ HeapSampleItemEvent("STRING_TYPE", string_number, string_bytes));
+ }
+
+ // Then do the other types.
+ for (int i = FIRST_NONSTRING_TYPE; i <= LAST_TYPE; ++i) {
+ if (info[i].number() > 0) {
+ LOG(isolate, HeapSampleItemEvent(info[i].name(), info[i].number(),
+ info[i].bytes()));
+ }
+ }
+ LOG(isolate, HeapSampleEndEvent("NewSpace", description));
+}
+
+
+void NewSpace::ReportStatistics() {
+#ifdef DEBUG
+ if (FLAG_heap_stats) {
+ float pct = static_cast<float>(Available()) / TotalCapacity();
+ PrintF(" capacity: %" V8_PTR_PREFIX
+ "d"
+ ", available: %" V8_PTR_PREFIX "d, %%%d\n",
+ TotalCapacity(), Available(), static_cast<int>(pct * 100));
+ PrintF("\n Object Histogram:\n");
+ for (int i = 0; i <= LAST_TYPE; i++) {
+ if (allocated_histogram_[i].number() > 0) {
+ PrintF(" %-34s%10d (%10d bytes)\n", allocated_histogram_[i].name(),
+ allocated_histogram_[i].number(),
+ allocated_histogram_[i].bytes());
+ }
+ }
+ PrintF("\n");
+ }
+#endif // DEBUG
+
+ if (FLAG_log_gc) {
+ Isolate* isolate = heap()->isolate();
+ DoReportStatistics(isolate, allocated_histogram_, "allocated");
+ DoReportStatistics(isolate, promoted_histogram_, "promoted");
+ }
+}
+
+
+void NewSpace::RecordAllocation(HeapObject* obj) {
+ InstanceType type = obj->map()->instance_type();
+ DCHECK(0 <= type && type <= LAST_TYPE);
+ allocated_histogram_[type].increment_number(1);
+ allocated_histogram_[type].increment_bytes(obj->Size());
+}
+
+
+void NewSpace::RecordPromotion(HeapObject* obj) {
+ InstanceType type = obj->map()->instance_type();
+ DCHECK(0 <= type && type <= LAST_TYPE);
+ promoted_histogram_[type].increment_number(1);
+ promoted_histogram_[type].increment_bytes(obj->Size());
+}
+
+
+size_t NewSpace::CommittedPhysicalMemory() {
+ if (!base::VirtualMemory::HasLazyCommits()) return CommittedMemory();
+ MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
+ size_t size = to_space_.CommittedPhysicalMemory();
+ if (from_space_.is_committed()) {
+ size += from_space_.CommittedPhysicalMemory();
+ }
+ return size;
+}
+
+
+// -----------------------------------------------------------------------------
+// Free lists for old object spaces implementation
+
+void FreeListNode::set_size(Heap* heap, int size_in_bytes) {
+ DCHECK(size_in_bytes > 0);
+ DCHECK(IsAligned(size_in_bytes, kPointerSize));
+
+ // We write a map and possibly size information to the block. If the block
+ // is big enough to be a FreeSpace with at least one extra word (the next
+ // pointer), we set its map to be the free space map and its size to an
+ // appropriate array length for the desired size from HeapObject::Size().
+ // If the block is too small (eg, one or two words), to hold both a size
+ // field and a next pointer, we give it a filler map that gives it the
+ // correct size.
+ if (size_in_bytes > FreeSpace::kHeaderSize) {
+ // Can't use FreeSpace::cast because it fails during deserialization.
+ // We have to set the size first with a release store before we store
+ // the map because a concurrent store buffer scan on scavenge must not
+ // observe a map with an invalid size.
+ FreeSpace* this_as_free_space = reinterpret_cast<FreeSpace*>(this);
+ this_as_free_space->nobarrier_set_size(size_in_bytes);
+ synchronized_set_map_no_write_barrier(heap->raw_unchecked_free_space_map());
+ } else if (size_in_bytes == kPointerSize) {
+ set_map_no_write_barrier(heap->raw_unchecked_one_pointer_filler_map());
+ } else if (size_in_bytes == 2 * kPointerSize) {
+ set_map_no_write_barrier(heap->raw_unchecked_two_pointer_filler_map());
+ } else {
+ UNREACHABLE();
+ }
+ // We would like to DCHECK(Size() == size_in_bytes) but this would fail during
+ // deserialization because the free space map is not done yet.
+}
+
+
+FreeListNode* FreeListNode::next() {
+ DCHECK(IsFreeListNode(this));
+ if (map() == GetHeap()->raw_unchecked_free_space_map()) {
+ DCHECK(map() == NULL || Size() >= kNextOffset + kPointerSize);
+ return reinterpret_cast<FreeListNode*>(
+ Memory::Address_at(address() + kNextOffset));
+ } else {
+ return reinterpret_cast<FreeListNode*>(
+ Memory::Address_at(address() + kPointerSize));
+ }
+}
+
+
+FreeListNode** FreeListNode::next_address() {
+ DCHECK(IsFreeListNode(this));
+ if (map() == GetHeap()->raw_unchecked_free_space_map()) {
+ DCHECK(Size() >= kNextOffset + kPointerSize);
+ return reinterpret_cast<FreeListNode**>(address() + kNextOffset);
+ } else {
+ return reinterpret_cast<FreeListNode**>(address() + kPointerSize);
+ }
+}
+
+
+void FreeListNode::set_next(FreeListNode* next) {
+ DCHECK(IsFreeListNode(this));
+ // While we are booting the VM the free space map will actually be null. So
+ // we have to make sure that we don't try to use it for anything at that
+ // stage.
+ if (map() == GetHeap()->raw_unchecked_free_space_map()) {
+ DCHECK(map() == NULL || Size() >= kNextOffset + kPointerSize);
+ base::NoBarrier_Store(
+ reinterpret_cast<base::AtomicWord*>(address() + kNextOffset),
+ reinterpret_cast<base::AtomicWord>(next));
+ } else {
+ base::NoBarrier_Store(
+ reinterpret_cast<base::AtomicWord*>(address() + kPointerSize),
+ reinterpret_cast<base::AtomicWord>(next));
+ }
+}
+
+
+intptr_t FreeListCategory::Concatenate(FreeListCategory* category) {
+ intptr_t free_bytes = 0;
+ if (category->top() != NULL) {
+ // This is safe (not going to deadlock) since Concatenate operations
+ // are never performed on the same free lists at the same time in
+ // reverse order.
+ base::LockGuard<base::Mutex> target_lock_guard(mutex());
+ base::LockGuard<base::Mutex> source_lock_guard(category->mutex());
+ DCHECK(category->end_ != NULL);
+ free_bytes = category->available();
+ if (end_ == NULL) {
+ end_ = category->end();
+ } else {
+ category->end()->set_next(top());
+ }
+ set_top(category->top());
+ base::NoBarrier_Store(&top_, category->top_);
+ available_ += category->available();
+ category->Reset();
+ }
+ return free_bytes;
+}
+
+
+void FreeListCategory::Reset() {
+ set_top(NULL);
+ set_end(NULL);
+ set_available(0);
+}
+
+
+intptr_t FreeListCategory::EvictFreeListItemsInList(Page* p) {
+ int sum = 0;
+ FreeListNode* t = top();
+ FreeListNode** n = &t;
+ while (*n != NULL) {
+ if (Page::FromAddress((*n)->address()) == p) {
+ FreeSpace* free_space = reinterpret_cast<FreeSpace*>(*n);
+ sum += free_space->Size();
+ *n = (*n)->next();
+ } else {
+ n = (*n)->next_address();
+ }
+ }
+ set_top(t);
+ if (top() == NULL) {
+ set_end(NULL);
+ }
+ available_ -= sum;
+ return sum;
+}
+
+
+bool FreeListCategory::ContainsPageFreeListItemsInList(Page* p) {
+ FreeListNode* node = top();
+ while (node != NULL) {
+ if (Page::FromAddress(node->address()) == p) return true;
+ node = node->next();
+ }
+ return false;
+}
+
+
+FreeListNode* FreeListCategory::PickNodeFromList(int* node_size) {
+ FreeListNode* node = top();
+
+ if (node == NULL) return NULL;
+
+ while (node != NULL &&
+ Page::FromAddress(node->address())->IsEvacuationCandidate()) {
+ available_ -= reinterpret_cast<FreeSpace*>(node)->Size();
+ node = node->next();
+ }
+
+ if (node != NULL) {
+ set_top(node->next());
+ *node_size = reinterpret_cast<FreeSpace*>(node)->Size();
+ available_ -= *node_size;
+ } else {
+ set_top(NULL);
+ }
+
+ if (top() == NULL) {
+ set_end(NULL);
+ }
+
+ return node;
+}
+
+
+FreeListNode* FreeListCategory::PickNodeFromList(int size_in_bytes,
+ int* node_size) {
+ FreeListNode* node = PickNodeFromList(node_size);
+ if (node != NULL && *node_size < size_in_bytes) {
+ Free(node, *node_size);
+ *node_size = 0;
+ return NULL;
+ }
+ return node;
+}
+
+
+void FreeListCategory::Free(FreeListNode* node, int size_in_bytes) {
+ node->set_next(top());
+ set_top(node);
+ if (end_ == NULL) {
+ end_ = node;
+ }
+ available_ += size_in_bytes;
+}
+
+
+void FreeListCategory::RepairFreeList(Heap* heap) {
+ FreeListNode* n = top();
+ while (n != NULL) {
+ Map** map_location = reinterpret_cast<Map**>(n->address());
+ if (*map_location == NULL) {
+ *map_location = heap->free_space_map();
+ } else {
+ DCHECK(*map_location == heap->free_space_map());
+ }
+ n = n->next();
+ }
+}
+
+
+FreeList::FreeList(PagedSpace* owner) : owner_(owner), heap_(owner->heap()) {
+ Reset();
+}
+
+
+intptr_t FreeList::Concatenate(FreeList* free_list) {
+ intptr_t free_bytes = 0;
+ free_bytes += small_list_.Concatenate(free_list->small_list());
+ free_bytes += medium_list_.Concatenate(free_list->medium_list());
+ free_bytes += large_list_.Concatenate(free_list->large_list());
+ free_bytes += huge_list_.Concatenate(free_list->huge_list());
+ return free_bytes;
+}
+
+
+void FreeList::Reset() {
+ small_list_.Reset();
+ medium_list_.Reset();
+ large_list_.Reset();
+ huge_list_.Reset();
+}
+
+
+int FreeList::Free(Address start, int size_in_bytes) {
+ if (size_in_bytes == 0) return 0;
+
+ FreeListNode* node = FreeListNode::FromAddress(start);
+ node->set_size(heap_, size_in_bytes);
+ Page* page = Page::FromAddress(start);
+
+ // Early return to drop too-small blocks on the floor.
+ if (size_in_bytes < kSmallListMin) {
+ page->add_non_available_small_blocks(size_in_bytes);
+ return size_in_bytes;
+ }
+
+ // Insert other blocks at the head of a free list of the appropriate
+ // magnitude.
+ if (size_in_bytes <= kSmallListMax) {
+ small_list_.Free(node, size_in_bytes);
+ page->add_available_in_small_free_list(size_in_bytes);
+ } else if (size_in_bytes <= kMediumListMax) {
+ medium_list_.Free(node, size_in_bytes);
+ page->add_available_in_medium_free_list(size_in_bytes);
+ } else if (size_in_bytes <= kLargeListMax) {
+ large_list_.Free(node, size_in_bytes);
+ page->add_available_in_large_free_list(size_in_bytes);
+ } else {
+ huge_list_.Free(node, size_in_bytes);
+ page->add_available_in_huge_free_list(size_in_bytes);
+ }
+
+ DCHECK(IsVeryLong() || available() == SumFreeLists());
+ return 0;
+}
+
+
+FreeListNode* FreeList::FindNodeFor(int size_in_bytes, int* node_size) {
+ FreeListNode* node = NULL;
+ Page* page = NULL;
+
+ if (size_in_bytes <= kSmallAllocationMax) {
+ node = small_list_.PickNodeFromList(node_size);
+ if (node != NULL) {
+ DCHECK(size_in_bytes <= *node_size);
+ page = Page::FromAddress(node->address());
+ page->add_available_in_small_free_list(-(*node_size));
+ DCHECK(IsVeryLong() || available() == SumFreeLists());
+ return node;
+ }
+ }
+
+ if (size_in_bytes <= kMediumAllocationMax) {
+ node = medium_list_.PickNodeFromList(node_size);
+ if (node != NULL) {
+ DCHECK(size_in_bytes <= *node_size);
+ page = Page::FromAddress(node->address());
+ page->add_available_in_medium_free_list(-(*node_size));
+ DCHECK(IsVeryLong() || available() == SumFreeLists());
+ return node;
+ }
+ }
+
+ if (size_in_bytes <= kLargeAllocationMax) {
+ node = large_list_.PickNodeFromList(node_size);
+ if (node != NULL) {
+ DCHECK(size_in_bytes <= *node_size);
+ page = Page::FromAddress(node->address());
+ page->add_available_in_large_free_list(-(*node_size));
+ DCHECK(IsVeryLong() || available() == SumFreeLists());
+ return node;
+ }
+ }
+
+ int huge_list_available = huge_list_.available();
+ FreeListNode* top_node = huge_list_.top();
+ for (FreeListNode** cur = &top_node; *cur != NULL;
+ cur = (*cur)->next_address()) {
+ FreeListNode* cur_node = *cur;
+ while (cur_node != NULL &&
+ Page::FromAddress(cur_node->address())->IsEvacuationCandidate()) {
+ int size = reinterpret_cast<FreeSpace*>(cur_node)->Size();
+ huge_list_available -= size;
+ page = Page::FromAddress(cur_node->address());
+ page->add_available_in_huge_free_list(-size);
+ cur_node = cur_node->next();
+ }
+
+ *cur = cur_node;
+ if (cur_node == NULL) {
+ huge_list_.set_end(NULL);
+ break;
+ }
+
+ DCHECK((*cur)->map() == heap_->raw_unchecked_free_space_map());
+ FreeSpace* cur_as_free_space = reinterpret_cast<FreeSpace*>(*cur);
+ int size = cur_as_free_space->Size();
+ if (size >= size_in_bytes) {
+ // Large enough node found. Unlink it from the list.
+ node = *cur;
+ *cur = node->next();
+ *node_size = size;
+ huge_list_available -= size;
+ page = Page::FromAddress(node->address());
+ page->add_available_in_huge_free_list(-size);
+ break;
+ }
+ }
+
+ huge_list_.set_top(top_node);
+ if (huge_list_.top() == NULL) {
+ huge_list_.set_end(NULL);
+ }
+ huge_list_.set_available(huge_list_available);
+
+ if (node != NULL) {
+ DCHECK(IsVeryLong() || available() == SumFreeLists());
+ return node;
+ }
+
+ if (size_in_bytes <= kSmallListMax) {
+ node = small_list_.PickNodeFromList(size_in_bytes, node_size);
+ if (node != NULL) {
+ DCHECK(size_in_bytes <= *node_size);
+ page = Page::FromAddress(node->address());
+ page->add_available_in_small_free_list(-(*node_size));
+ }
+ } else if (size_in_bytes <= kMediumListMax) {
+ node = medium_list_.PickNodeFromList(size_in_bytes, node_size);
+ if (node != NULL) {
+ DCHECK(size_in_bytes <= *node_size);
+ page = Page::FromAddress(node->address());
+ page->add_available_in_medium_free_list(-(*node_size));
+ }
+ } else if (size_in_bytes <= kLargeListMax) {
+ node = large_list_.PickNodeFromList(size_in_bytes, node_size);
+ if (node != NULL) {
+ DCHECK(size_in_bytes <= *node_size);
+ page = Page::FromAddress(node->address());
+ page->add_available_in_large_free_list(-(*node_size));
+ }
+ }
+
+ DCHECK(IsVeryLong() || available() == SumFreeLists());
+ return node;
+}
+
+
+// Allocation on the old space free list. If it succeeds then a new linear
+// allocation space has been set up with the top and limit of the space. If
+// the allocation fails then NULL is returned, and the caller can perform a GC
+// or allocate a new page before retrying.
+HeapObject* FreeList::Allocate(int size_in_bytes) {
+ DCHECK(0 < size_in_bytes);
+ DCHECK(size_in_bytes <= kMaxBlockSize);
+ DCHECK(IsAligned(size_in_bytes, kPointerSize));
+ // Don't free list allocate if there is linear space available.
+ DCHECK(owner_->limit() - owner_->top() < size_in_bytes);
+
+ int old_linear_size = static_cast<int>(owner_->limit() - owner_->top());
+ // Mark the old linear allocation area with a free space map so it can be
+ // skipped when scanning the heap. This also puts it back in the free list
+ // if it is big enough.
+ owner_->Free(owner_->top(), old_linear_size);
+
+ owner_->heap()->incremental_marking()->OldSpaceStep(size_in_bytes -
+ old_linear_size);
+
+ int new_node_size = 0;
+ FreeListNode* new_node = FindNodeFor(size_in_bytes, &new_node_size);
+ if (new_node == NULL) {
+ owner_->SetTopAndLimit(NULL, NULL);
+ return NULL;
+ }
+
+ int bytes_left = new_node_size - size_in_bytes;
+ DCHECK(bytes_left >= 0);
+
+#ifdef DEBUG
+ for (int i = 0; i < size_in_bytes / kPointerSize; i++) {
+ reinterpret_cast<Object**>(new_node->address())[i] =
+ Smi::FromInt(kCodeZapValue);
+ }
+#endif
+
+ // The old-space-step might have finished sweeping and restarted marking.
+ // Verify that it did not turn the page of the new node into an evacuation
+ // candidate.
+ DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(new_node));
+
+ const int kThreshold = IncrementalMarking::kAllocatedThreshold;
+
+ // Memory in the linear allocation area is counted as allocated. We may free
+ // a little of this again immediately - see below.
+ owner_->Allocate(new_node_size);
+
+ if (owner_->heap()->inline_allocation_disabled()) {
+ // Keep the linear allocation area empty if requested to do so, just
+ // return area back to the free list instead.
+ owner_->Free(new_node->address() + size_in_bytes, bytes_left);
+ DCHECK(owner_->top() == NULL && owner_->limit() == NULL);
+ } else if (bytes_left > kThreshold &&
+ owner_->heap()->incremental_marking()->IsMarkingIncomplete() &&
+ FLAG_incremental_marking_steps) {
+ int linear_size = owner_->RoundSizeDownToObjectAlignment(kThreshold);
+ // We don't want to give too large linear areas to the allocator while
+ // incremental marking is going on, because we won't check again whether
+ // we want to do another increment until the linear area is used up.
+ owner_->Free(new_node->address() + size_in_bytes + linear_size,
+ new_node_size - size_in_bytes - linear_size);
+ owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
+ new_node->address() + size_in_bytes + linear_size);
+ } else if (bytes_left > 0) {
+ // Normally we give the rest of the node to the allocator as its new
+ // linear allocation area.
+ owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
+ new_node->address() + new_node_size);
+ } else {
+ // TODO(gc) Try not freeing linear allocation region when bytes_left
+ // are zero.
+ owner_->SetTopAndLimit(NULL, NULL);
+ }
+
+ return new_node;
+}
+
+
+intptr_t FreeList::EvictFreeListItems(Page* p) {
+ intptr_t sum = huge_list_.EvictFreeListItemsInList(p);
+ p->set_available_in_huge_free_list(0);
+
+ if (sum < p->area_size()) {
+ sum += small_list_.EvictFreeListItemsInList(p) +
+ medium_list_.EvictFreeListItemsInList(p) +
+ large_list_.EvictFreeListItemsInList(p);
+ p->set_available_in_small_free_list(0);
+ p->set_available_in_medium_free_list(0);
+ p->set_available_in_large_free_list(0);
+ }
+
+ return sum;
+}
+
+
+bool FreeList::ContainsPageFreeListItems(Page* p) {
+ return huge_list_.EvictFreeListItemsInList(p) ||
+ small_list_.EvictFreeListItemsInList(p) ||
+ medium_list_.EvictFreeListItemsInList(p) ||
+ large_list_.EvictFreeListItemsInList(p);
+}
+
+
+void FreeList::RepairLists(Heap* heap) {
+ small_list_.RepairFreeList(heap);
+ medium_list_.RepairFreeList(heap);
+ large_list_.RepairFreeList(heap);
+ huge_list_.RepairFreeList(heap);
+}
+
+
+#ifdef DEBUG
+intptr_t FreeListCategory::SumFreeList() {
+ intptr_t sum = 0;
+ FreeListNode* cur = top();
+ while (cur != NULL) {
+ DCHECK(cur->map() == cur->GetHeap()->raw_unchecked_free_space_map());
+ FreeSpace* cur_as_free_space = reinterpret_cast<FreeSpace*>(cur);
+ sum += cur_as_free_space->nobarrier_size();
+ cur = cur->next();
+ }
+ return sum;
+}
+
+
+static const int kVeryLongFreeList = 500;
+
+
+int FreeListCategory::FreeListLength() {
+ int length = 0;
+ FreeListNode* cur = top();
+ while (cur != NULL) {
+ length++;
+ cur = cur->next();
+ if (length == kVeryLongFreeList) return length;
+ }
+ return length;
+}
+
+
+bool FreeList::IsVeryLong() {
+ if (small_list_.FreeListLength() == kVeryLongFreeList) return true;
+ if (medium_list_.FreeListLength() == kVeryLongFreeList) return true;
+ if (large_list_.FreeListLength() == kVeryLongFreeList) return true;
+ if (huge_list_.FreeListLength() == kVeryLongFreeList) return true;
+ return false;
+}
+
+
+// This can take a very long time because it is linear in the number of entries
+// on the free list, so it should not be called if FreeListLength returns
+// kVeryLongFreeList.
+intptr_t FreeList::SumFreeLists() {
+ intptr_t sum = small_list_.SumFreeList();
+ sum += medium_list_.SumFreeList();
+ sum += large_list_.SumFreeList();
+ sum += huge_list_.SumFreeList();
+ return sum;
+}
+#endif
+
+
+// -----------------------------------------------------------------------------
+// OldSpace implementation
+
+void PagedSpace::PrepareForMarkCompact() {
+ // We don't have a linear allocation area while sweeping. It will be restored
+ // on the first allocation after the sweep.
+ EmptyAllocationInfo();
+
+ // This counter will be increased for pages which will be swept by the
+ // sweeper threads.
+ unswept_free_bytes_ = 0;
+
+ // Clear the free list before a full GC---it will be rebuilt afterward.
+ free_list_.Reset();
+}
+
+
+intptr_t PagedSpace::SizeOfObjects() {
+ DCHECK(heap()->mark_compact_collector()->sweeping_in_progress() ||
+ (unswept_free_bytes_ == 0));
+ return Size() - unswept_free_bytes_ - (limit() - top());
+}
+
+
+// After we have booted, we have created a map which represents free space
+// on the heap. If there was already a free list then the elements on it
+// were created with the wrong FreeSpaceMap (normally NULL), so we need to
+// fix them.
+void PagedSpace::RepairFreeListsAfterBoot() { free_list_.RepairLists(heap()); }
+
+
+void PagedSpace::EvictEvacuationCandidatesFromFreeLists() {
+ if (allocation_info_.top() >= allocation_info_.limit()) return;
+
+ if (Page::FromAllocationTop(allocation_info_.top())
+ ->IsEvacuationCandidate()) {
+ // Create filler object to keep page iterable if it was iterable.
+ int remaining =
+ static_cast<int>(allocation_info_.limit() - allocation_info_.top());
+ heap()->CreateFillerObjectAt(allocation_info_.top(), remaining);
+
+ allocation_info_.set_top(NULL);
+ allocation_info_.set_limit(NULL);
+ }
+}
+
+
+HeapObject* PagedSpace::WaitForSweeperThreadsAndRetryAllocation(
+ int size_in_bytes) {
+ MarkCompactCollector* collector = heap()->mark_compact_collector();
+ if (collector->sweeping_in_progress()) {
+ // Wait for the sweeper threads here and complete the sweeping phase.
+ collector->EnsureSweepingCompleted();
+
+ // After waiting for the sweeper threads, there may be new free-list
+ // entries.
+ return free_list_.Allocate(size_in_bytes);
+ }
+ return NULL;
+}
+
+
+HeapObject* PagedSpace::SlowAllocateRaw(int size_in_bytes) {
+ // Allocation in this space has failed.
+
+ MarkCompactCollector* collector = heap()->mark_compact_collector();
+ // Sweeping is still in progress.
+ if (collector->sweeping_in_progress()) {
+ // First try to refill the free-list, concurrent sweeper threads
+ // may have freed some objects in the meantime.
+ collector->RefillFreeList(this);
+
+ // Retry the free list allocation.
+ HeapObject* object = free_list_.Allocate(size_in_bytes);
+ if (object != NULL) return object;
+
+ // If sweeping is still in progress try to sweep pages on the main thread.
+ int free_chunk = collector->SweepInParallel(this, size_in_bytes);
+ collector->RefillFreeList(this);
+ if (free_chunk >= size_in_bytes) {
+ HeapObject* object = free_list_.Allocate(size_in_bytes);
+ // We should be able to allocate an object here since we just freed that
+ // much memory.
+ DCHECK(object != NULL);
+ if (object != NULL) return object;
+ }
+ }
+
+ // Free list allocation failed and there is no next page. Fail if we have
+ // hit the old generation size limit that should cause a garbage
+ // collection.
+ if (!heap()->always_allocate() &&
+ heap()->OldGenerationAllocationLimitReached()) {
+ // If sweeper threads are active, wait for them at that point and steal
+ // elements form their free-lists.
+ HeapObject* object = WaitForSweeperThreadsAndRetryAllocation(size_in_bytes);
+ if (object != NULL) return object;
+ }
+
+ // Try to expand the space and allocate in the new next page.
+ if (Expand()) {
+ DCHECK(CountTotalPages() > 1 || size_in_bytes <= free_list_.available());
+ return free_list_.Allocate(size_in_bytes);
+ }
+
+ // If sweeper threads are active, wait for them at that point and steal
+ // elements form their free-lists. Allocation may still fail their which
+ // would indicate that there is not enough memory for the given allocation.
+ return WaitForSweeperThreadsAndRetryAllocation(size_in_bytes);
+}
+
+
+#ifdef DEBUG
+void PagedSpace::ReportCodeStatistics(Isolate* isolate) {
+ CommentStatistic* comments_statistics =
+ isolate->paged_space_comments_statistics();
+ ReportCodeKindStatistics(isolate->code_kind_statistics());
+ PrintF(
+ "Code comment statistics (\" [ comment-txt : size/ "
+ "count (average)\"):\n");
+ for (int i = 0; i <= CommentStatistic::kMaxComments; i++) {
+ const CommentStatistic& cs = comments_statistics[i];
+ if (cs.size > 0) {
+ PrintF(" %-30s: %10d/%6d (%d)\n", cs.comment, cs.size, cs.count,
+ cs.size / cs.count);
+ }
+ }
+ PrintF("\n");
+}
+
+
+void PagedSpace::ResetCodeStatistics(Isolate* isolate) {
+ CommentStatistic* comments_statistics =
+ isolate->paged_space_comments_statistics();
+ ClearCodeKindStatistics(isolate->code_kind_statistics());
+ for (int i = 0; i < CommentStatistic::kMaxComments; i++) {
+ comments_statistics[i].Clear();
+ }
+ comments_statistics[CommentStatistic::kMaxComments].comment = "Unknown";
+ comments_statistics[CommentStatistic::kMaxComments].size = 0;
+ comments_statistics[CommentStatistic::kMaxComments].count = 0;
+}
+
+
+// Adds comment to 'comment_statistics' table. Performance OK as long as
+// 'kMaxComments' is small
+static void EnterComment(Isolate* isolate, const char* comment, int delta) {
+ CommentStatistic* comments_statistics =
+ isolate->paged_space_comments_statistics();
+ // Do not count empty comments
+ if (delta <= 0) return;
+ CommentStatistic* cs = &comments_statistics[CommentStatistic::kMaxComments];
+ // Search for a free or matching entry in 'comments_statistics': 'cs'
+ // points to result.
+ for (int i = 0; i < CommentStatistic::kMaxComments; i++) {
+ if (comments_statistics[i].comment == NULL) {
+ cs = &comments_statistics[i];
+ cs->comment = comment;
+ break;
+ } else if (strcmp(comments_statistics[i].comment, comment) == 0) {
+ cs = &comments_statistics[i];
+ break;
+ }
+ }
+ // Update entry for 'comment'
+ cs->size += delta;
+ cs->count += 1;
+}
+
+
+// Call for each nested comment start (start marked with '[ xxx', end marked
+// with ']'. RelocIterator 'it' must point to a comment reloc info.
+static void CollectCommentStatistics(Isolate* isolate, RelocIterator* it) {
+ DCHECK(!it->done());
+ DCHECK(it->rinfo()->rmode() == RelocInfo::COMMENT);
+ const char* tmp = reinterpret_cast<const char*>(it->rinfo()->data());
+ if (tmp[0] != '[') {
+ // Not a nested comment; skip
+ return;
+ }
+
+ // Search for end of nested comment or a new nested comment
+ const char* const comment_txt =
+ reinterpret_cast<const char*>(it->rinfo()->data());
+ const byte* prev_pc = it->rinfo()->pc();
+ int flat_delta = 0;
+ it->next();
+ while (true) {
+ // All nested comments must be terminated properly, and therefore exit
+ // from loop.
+ DCHECK(!it->done());
+ if (it->rinfo()->rmode() == RelocInfo::COMMENT) {
+ const char* const txt =
+ reinterpret_cast<const char*>(it->rinfo()->data());
+ flat_delta += static_cast<int>(it->rinfo()->pc() - prev_pc);
+ if (txt[0] == ']') break; // End of nested comment
+ // A new comment
+ CollectCommentStatistics(isolate, it);
+ // Skip code that was covered with previous comment
+ prev_pc = it->rinfo()->pc();
+ }
+ it->next();
+ }
+ EnterComment(isolate, comment_txt, flat_delta);
+}
+
+
+// Collects code size statistics:
+// - by code kind
+// - by code comment
+void PagedSpace::CollectCodeStatistics() {
+ Isolate* isolate = heap()->isolate();
+ HeapObjectIterator obj_it(this);
+ for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next()) {
+ if (obj->IsCode()) {
+ Code* code = Code::cast(obj);
+ isolate->code_kind_statistics()[code->kind()] += code->Size();
+ RelocIterator it(code);
+ int delta = 0;
+ const byte* prev_pc = code->instruction_start();
+ while (!it.done()) {
+ if (it.rinfo()->rmode() == RelocInfo::COMMENT) {
+ delta += static_cast<int>(it.rinfo()->pc() - prev_pc);
+ CollectCommentStatistics(isolate, &it);
+ prev_pc = it.rinfo()->pc();
+ }
+ it.next();
+ }
+
+ DCHECK(code->instruction_start() <= prev_pc &&
+ prev_pc <= code->instruction_end());
+ delta += static_cast<int>(code->instruction_end() - prev_pc);
+ EnterComment(isolate, "NoComment", delta);
+ }
+ }
+}
+
+
+void PagedSpace::ReportStatistics() {
+ int pct = static_cast<int>(Available() * 100 / Capacity());
+ PrintF(" capacity: %" V8_PTR_PREFIX
+ "d"
+ ", waste: %" V8_PTR_PREFIX
+ "d"
+ ", available: %" V8_PTR_PREFIX "d, %%%d\n",
+ Capacity(), Waste(), Available(), pct);
+
+ if (heap()->mark_compact_collector()->sweeping_in_progress()) {
+ heap()->mark_compact_collector()->EnsureSweepingCompleted();
+ }
+ ClearHistograms(heap()->isolate());
+ HeapObjectIterator obj_it(this);
+ for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next())
+ CollectHistogramInfo(obj);
+ ReportHistogram(heap()->isolate(), true);
+}
+#endif
+
+
+// -----------------------------------------------------------------------------
+// MapSpace implementation
+// TODO(mvstanton): this is weird...the compiler can't make a vtable unless
+// there is at least one non-inlined virtual function. I would prefer to hide
+// the VerifyObject definition behind VERIFY_HEAP.
+
+void MapSpace::VerifyObject(HeapObject* object) { CHECK(object->IsMap()); }
+
+
+// -----------------------------------------------------------------------------
+// CellSpace and PropertyCellSpace implementation
+// TODO(mvstanton): this is weird...the compiler can't make a vtable unless
+// there is at least one non-inlined virtual function. I would prefer to hide
+// the VerifyObject definition behind VERIFY_HEAP.
+
+void CellSpace::VerifyObject(HeapObject* object) { CHECK(object->IsCell()); }
+
+
+void PropertyCellSpace::VerifyObject(HeapObject* object) {
+ CHECK(object->IsPropertyCell());
+}
+
+
+// -----------------------------------------------------------------------------
+// LargeObjectIterator
+
+LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space) {
+ current_ = space->first_page_;
+ size_func_ = NULL;
+}
+
+
+LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space,
+ HeapObjectCallback size_func) {
+ current_ = space->first_page_;
+ size_func_ = size_func;
+}
+
+
+HeapObject* LargeObjectIterator::Next() {
+ if (current_ == NULL) return NULL;
+
+ HeapObject* object = current_->GetObject();
+ current_ = current_->next_page();
+ return object;
+}
+
+
+// -----------------------------------------------------------------------------
+// LargeObjectSpace
+static bool ComparePointers(void* key1, void* key2) { return key1 == key2; }
+
+
+LargeObjectSpace::LargeObjectSpace(Heap* heap, intptr_t max_capacity,
+ AllocationSpace id)
+ : Space(heap, id, NOT_EXECUTABLE), // Managed on a per-allocation basis
+ max_capacity_(max_capacity),
+ first_page_(NULL),
+ size_(0),
+ page_count_(0),
+ objects_size_(0),
+ chunk_map_(ComparePointers, 1024) {}
+
+
+bool LargeObjectSpace::SetUp() {
+ first_page_ = NULL;
+ size_ = 0;
+ maximum_committed_ = 0;
+ page_count_ = 0;
+ objects_size_ = 0;
+ chunk_map_.Clear();
+ return true;
+}
+
+
+void LargeObjectSpace::TearDown() {
+ while (first_page_ != NULL) {
+ LargePage* page = first_page_;
+ first_page_ = first_page_->next_page();
+ LOG(heap()->isolate(), DeleteEvent("LargeObjectChunk", page->address()));
+
+ ObjectSpace space = static_cast<ObjectSpace>(1 << identity());
+ heap()->isolate()->memory_allocator()->PerformAllocationCallback(
+ space, kAllocationActionFree, page->size());
+ heap()->isolate()->memory_allocator()->Free(page);
+ }
+ SetUp();
+}
+
+
+AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
+ Executability executable) {
+ // Check if we want to force a GC before growing the old space further.
+ // If so, fail the allocation.
+ if (!heap()->always_allocate() &&
+ heap()->OldGenerationAllocationLimitReached()) {
+ return AllocationResult::Retry(identity());
+ }
+
+ if (Size() + object_size > max_capacity_) {
+ return AllocationResult::Retry(identity());
+ }
+
+ LargePage* page = heap()->isolate()->memory_allocator()->AllocateLargePage(
+ object_size, this, executable);
+ if (page == NULL) return AllocationResult::Retry(identity());
+ DCHECK(page->area_size() >= object_size);
+
+ size_ += static_cast<int>(page->size());
+ objects_size_ += object_size;
+ page_count_++;
+ page->set_next_page(first_page_);
+ first_page_ = page;
+
+ if (size_ > maximum_committed_) {
+ maximum_committed_ = size_;
+ }
+
+ // Register all MemoryChunk::kAlignment-aligned chunks covered by
+ // this large page in the chunk map.
+ uintptr_t base = reinterpret_cast<uintptr_t>(page) / MemoryChunk::kAlignment;
+ uintptr_t limit = base + (page->size() - 1) / MemoryChunk::kAlignment;
+ for (uintptr_t key = base; key <= limit; key++) {
+ HashMap::Entry* entry = chunk_map_.Lookup(reinterpret_cast<void*>(key),
+ static_cast<uint32_t>(key), true);
+ DCHECK(entry != NULL);
+ entry->value = page;
+ }
+
+ HeapObject* object = page->GetObject();
+
+ MSAN_ALLOCATED_UNINITIALIZED_MEMORY(object->address(), object_size);
+
+ if (Heap::ShouldZapGarbage()) {
+ // Make the object consistent so the heap can be verified in OldSpaceStep.
+ // We only need to do this in debug builds or if verify_heap is on.
+ reinterpret_cast<Object**>(object->address())[0] =
+ heap()->fixed_array_map();
+ reinterpret_cast<Object**>(object->address())[1] = Smi::FromInt(0);
+ }
+
+ heap()->incremental_marking()->OldSpaceStep(object_size);
+ return object;
+}
+
+
+size_t LargeObjectSpace::CommittedPhysicalMemory() {
+ if (!base::VirtualMemory::HasLazyCommits()) return CommittedMemory();
+ size_t size = 0;
+ LargePage* current = first_page_;
+ while (current != NULL) {
+ size += current->CommittedPhysicalMemory();
+ current = current->next_page();
+ }
+ return size;
+}
+
+
+// GC support
+Object* LargeObjectSpace::FindObject(Address a) {
+ LargePage* page = FindPage(a);
+ if (page != NULL) {
+ return page->GetObject();
+ }
+ return Smi::FromInt(0); // Signaling not found.
+}
+
+
+LargePage* LargeObjectSpace::FindPage(Address a) {
+ uintptr_t key = reinterpret_cast<uintptr_t>(a) / MemoryChunk::kAlignment;
+ HashMap::Entry* e = chunk_map_.Lookup(reinterpret_cast<void*>(key),
+ static_cast<uint32_t>(key), false);
+ if (e != NULL) {
+ DCHECK(e->value != NULL);
+ LargePage* page = reinterpret_cast<LargePage*>(e->value);
+ DCHECK(page->is_valid());
+ if (page->Contains(a)) {
+ return page;
+ }
+ }
+ return NULL;
+}
+
+
+void LargeObjectSpace::FreeUnmarkedObjects() {
+ LargePage* previous = NULL;
+ LargePage* current = first_page_;
+ while (current != NULL) {
+ HeapObject* object = current->GetObject();
+ // Can this large page contain pointers to non-trivial objects. No other
+ // pointer object is this big.
+ bool is_pointer_object = object->IsFixedArray();
+ MarkBit mark_bit = Marking::MarkBitFrom(object);
+ if (mark_bit.Get()) {
+ mark_bit.Clear();
+ Page::FromAddress(object->address())->ResetProgressBar();
+ Page::FromAddress(object->address())->ResetLiveBytes();
+ previous = current;
+ current = current->next_page();
+ } else {
+ LargePage* page = current;
+ // Cut the chunk out from the chunk list.
+ current = current->next_page();
+ if (previous == NULL) {
+ first_page_ = current;
+ } else {
+ previous->set_next_page(current);
+ }
+
+ // Free the chunk.
+ heap()->mark_compact_collector()->ReportDeleteIfNeeded(object,
+ heap()->isolate());
+ size_ -= static_cast<int>(page->size());
+ objects_size_ -= object->Size();
+ page_count_--;
+
+ // Remove entries belonging to this page.
+ // Use variable alignment to help pass length check (<= 80 characters)
+ // of single line in tools/presubmit.py.
+ const intptr_t alignment = MemoryChunk::kAlignment;
+ uintptr_t base = reinterpret_cast<uintptr_t>(page) / alignment;
+ uintptr_t limit = base + (page->size() - 1) / alignment;
+ for (uintptr_t key = base; key <= limit; key++) {
+ chunk_map_.Remove(reinterpret_cast<void*>(key),
+ static_cast<uint32_t>(key));
+ }
+
+ if (is_pointer_object) {
+ heap()->QueueMemoryChunkForFree(page);
+ } else {
+ heap()->isolate()->memory_allocator()->Free(page);
+ }
+ }
+ }
+ heap()->FreeQueuedChunks();
+}
+
+
+bool LargeObjectSpace::Contains(HeapObject* object) {
+ Address address = object->address();
+ MemoryChunk* chunk = MemoryChunk::FromAddress(address);
+
+ bool owned = (chunk->owner() == this);
+
+ SLOW_DCHECK(!owned || FindObject(address)->IsHeapObject());
+
+ return owned;
+}
+
+
+#ifdef VERIFY_HEAP
+// We do not assume that the large object iterator works, because it depends
+// on the invariants we are checking during verification.
+void LargeObjectSpace::Verify() {
+ for (LargePage* chunk = first_page_; chunk != NULL;
+ chunk = chunk->next_page()) {
+ // Each chunk contains an object that starts at the large object page's
+ // object area start.
+ HeapObject* object = chunk->GetObject();
+ Page* page = Page::FromAddress(object->address());
+ CHECK(object->address() == page->area_start());
+
+ // The first word should be a map, and we expect all map pointers to be
+ // in map space.
+ Map* map = object->map();
+ CHECK(map->IsMap());
+ CHECK(heap()->map_space()->Contains(map));
+
+ // We have only code, sequential strings, external strings
+ // (sequential strings that have been morphed into external
+ // strings), fixed arrays, byte arrays, and constant pool arrays in the
+ // large object space.
+ CHECK(object->IsCode() || object->IsSeqString() ||
+ object->IsExternalString() || object->IsFixedArray() ||
+ object->IsFixedDoubleArray() || object->IsByteArray() ||
+ object->IsConstantPoolArray());
+
+ // The object itself should look OK.
+ object->ObjectVerify();
+
+ // Byte arrays and strings don't have interior pointers.
+ if (object->IsCode()) {
+ VerifyPointersVisitor code_visitor;
+ object->IterateBody(map->instance_type(), object->Size(), &code_visitor);
+ } else if (object->IsFixedArray()) {
+ FixedArray* array = FixedArray::cast(object);
+ for (int j = 0; j < array->length(); j++) {
+ Object* element = array->get(j);
+ if (element->IsHeapObject()) {
+ HeapObject* element_object = HeapObject::cast(element);
+ CHECK(heap()->Contains(element_object));
+ CHECK(element_object->map()->IsMap());
+ }
+ }
+ }
+ }
+}
+#endif
+
+
+#ifdef DEBUG
+void LargeObjectSpace::Print() {
+ OFStream os(stdout);
+ LargeObjectIterator it(this);
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ obj->Print(os);
+ }
+}
+
+
+void LargeObjectSpace::ReportStatistics() {
+ PrintF(" size: %" V8_PTR_PREFIX "d\n", size_);
+ int num_objects = 0;
+ ClearHistograms(heap()->isolate());
+ LargeObjectIterator it(this);
+ for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
+ num_objects++;
+ CollectHistogramInfo(obj);
+ }
+
+ PrintF(
+ " number of objects %d, "
+ "size of objects %" V8_PTR_PREFIX "d\n",
+ num_objects, objects_size_);
+ if (num_objects > 0) ReportHistogram(heap()->isolate(), false);
+}
+
+
+void LargeObjectSpace::CollectCodeStatistics() {
+ Isolate* isolate = heap()->isolate();
+ LargeObjectIterator obj_it(this);
+ for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next()) {
+ if (obj->IsCode()) {
+ Code* code = Code::cast(obj);
+ isolate->code_kind_statistics()[code->kind()] += code->Size();
+ }
+ }
+}
+
+
+void Page::Print() {
+ // Make a best-effort to print the objects in the page.
+ PrintF("Page@%p in %s\n", this->address(),
+ AllocationSpaceName(this->owner()->identity()));
+ printf(" --------------------------------------\n");
+ HeapObjectIterator objects(this, heap()->GcSafeSizeOfOldObjectFunction());
+ unsigned mark_size = 0;
+ for (HeapObject* object = objects.Next(); object != NULL;
+ object = objects.Next()) {
+ bool is_marked = Marking::MarkBitFrom(object).Get();
+ PrintF(" %c ", (is_marked ? '!' : ' ')); // Indent a little.
+ if (is_marked) {
+ mark_size += heap()->GcSafeSizeOfOldObjectFunction()(object);
+ }
+ object->ShortPrint();
+ PrintF("\n");
+ }
+ printf(" --------------------------------------\n");
+ printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
+}
+
+#endif // DEBUG
+}
+} // namespace v8::internal
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
new file mode 100644
index 0000000..9ecb3c4
--- /dev/null
+++ b/src/heap/spaces.h
@@ -0,0 +1,2886 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_SPACES_H_
+#define V8_HEAP_SPACES_H_
+
+#include "src/allocation.h"
+#include "src/base/atomicops.h"
+#include "src/base/bits.h"
+#include "src/base/platform/mutex.h"
+#include "src/hashmap.h"
+#include "src/list.h"
+#include "src/log.h"
+#include "src/utils.h"
+
+namespace v8 {
+namespace internal {
+
+class Isolate;
+
+// -----------------------------------------------------------------------------
+// Heap structures:
+//
+// A JS heap consists of a young generation, an old generation, and a large
+// object space. The young generation is divided into two semispaces. A
+// scavenger implements Cheney's copying algorithm. The old generation is
+// separated into a map space and an old object space. The map space contains
+// all (and only) map objects, the rest of old objects go into the old space.
+// The old generation is collected by a mark-sweep-compact collector.
+//
+// The semispaces of the young generation are contiguous. The old and map
+// spaces consists of a list of pages. A page has a page header and an object
+// area.
+//
+// There is a separate large object space for objects larger than
+// Page::kMaxHeapObjectSize, so that they do not have to move during
+// collection. The large object space is paged. Pages in large object space
+// may be larger than the page size.
+//
+// A store-buffer based write barrier is used to keep track of intergenerational
+// references. See heap/store-buffer.h.
+//
+// During scavenges and mark-sweep collections we sometimes (after a store
+// buffer overflow) iterate intergenerational pointers without decoding heap
+// object maps so if the page belongs to old pointer space or large object
+// space it is essential to guarantee that the page does not contain any
+// garbage pointers to new space: every pointer aligned word which satisfies
+// the Heap::InNewSpace() predicate must be a pointer to a live heap object in
+// new space. Thus objects in old pointer and large object spaces should have a
+// special layout (e.g. no bare integer fields). This requirement does not
+// apply to map space which is iterated in a special fashion. However we still
+// require pointer fields of dead maps to be cleaned.
+//
+// To enable lazy cleaning of old space pages we can mark chunks of the page
+// as being garbage. Garbage sections are marked with a special map. These
+// sections are skipped when scanning the page, even if we are otherwise
+// scanning without regard for object boundaries. Garbage sections are chained
+// together to form a free list after a GC. Garbage sections created outside
+// of GCs by object trunctation etc. may not be in the free list chain. Very
+// small free spaces are ignored, they need only be cleaned of bogus pointers
+// into new space.
+//
+// Each page may have up to one special garbage section. The start of this
+// section is denoted by the top field in the space. The end of the section
+// is denoted by the limit field in the space. This special garbage section
+// is not marked with a free space map in the data. The point of this section
+// is to enable linear allocation without having to constantly update the byte
+// array every time the top field is updated and a new object is created. The
+// special garbage section is not in the chain of garbage sections.
+//
+// Since the top and limit fields are in the space, not the page, only one page
+// has a special garbage section, and if the top and limit are equal then there
+// is no special garbage section.
+
+// Some assertion macros used in the debugging mode.
+
+#define DCHECK_PAGE_ALIGNED(address) \
+ DCHECK((OffsetFrom(address) & Page::kPageAlignmentMask) == 0)
+
+#define DCHECK_OBJECT_ALIGNED(address) \
+ DCHECK((OffsetFrom(address) & kObjectAlignmentMask) == 0)
+
+#define DCHECK_OBJECT_SIZE(size) \
+ DCHECK((0 < size) && (size <= Page::kMaxRegularHeapObjectSize))
+
+#define DCHECK_PAGE_OFFSET(offset) \
+ DCHECK((Page::kObjectStartOffset <= offset) && (offset <= Page::kPageSize))
+
+#define DCHECK_MAP_PAGE_INDEX(index) \
+ DCHECK((0 <= index) && (index <= MapSpace::kMaxMapPageIndex))
+
+
+class PagedSpace;
+class MemoryAllocator;
+class AllocationInfo;
+class Space;
+class FreeList;
+class MemoryChunk;
+
+class MarkBit {
+ public:
+ typedef uint32_t CellType;
+
+ inline MarkBit(CellType* cell, CellType mask, bool data_only)
+ : cell_(cell), mask_(mask), data_only_(data_only) {}
+
+ inline CellType* cell() { return cell_; }
+ inline CellType mask() { return mask_; }
+
+#ifdef DEBUG
+ bool operator==(const MarkBit& other) {
+ return cell_ == other.cell_ && mask_ == other.mask_;
+ }
+#endif
+
+ inline void Set() { *cell_ |= mask_; }
+ inline bool Get() { return (*cell_ & mask_) != 0; }
+ inline void Clear() { *cell_ &= ~mask_; }
+
+ inline bool data_only() { return data_only_; }
+
+ inline MarkBit Next() {
+ CellType new_mask = mask_ << 1;
+ if (new_mask == 0) {
+ return MarkBit(cell_ + 1, 1, data_only_);
+ } else {
+ return MarkBit(cell_, new_mask, data_only_);
+ }
+ }
+
+ private:
+ CellType* cell_;
+ CellType mask_;
+ // This boolean indicates that the object is in a data-only space with no
+ // pointers. This enables some optimizations when marking.
+ // It is expected that this field is inlined and turned into control flow
+ // at the place where the MarkBit object is created.
+ bool data_only_;
+};
+
+
+// Bitmap is a sequence of cells each containing fixed number of bits.
+class Bitmap {
+ public:
+ static const uint32_t kBitsPerCell = 32;
+ static const uint32_t kBitsPerCellLog2 = 5;
+ static const uint32_t kBitIndexMask = kBitsPerCell - 1;
+ static const uint32_t kBytesPerCell = kBitsPerCell / kBitsPerByte;
+ static const uint32_t kBytesPerCellLog2 = kBitsPerCellLog2 - kBitsPerByteLog2;
+
+ static const size_t kLength = (1 << kPageSizeBits) >> (kPointerSizeLog2);
+
+ static const size_t kSize =
+ (1 << kPageSizeBits) >> (kPointerSizeLog2 + kBitsPerByteLog2);
+
+
+ static int CellsForLength(int length) {
+ return (length + kBitsPerCell - 1) >> kBitsPerCellLog2;
+ }
+
+ int CellsCount() { return CellsForLength(kLength); }
+
+ static int SizeFor(int cells_count) {
+ return sizeof(MarkBit::CellType) * cells_count;
+ }
+
+ INLINE(static uint32_t IndexToCell(uint32_t index)) {
+ return index >> kBitsPerCellLog2;
+ }
+
+ INLINE(static uint32_t CellToIndex(uint32_t index)) {
+ return index << kBitsPerCellLog2;
+ }
+
+ INLINE(static uint32_t CellAlignIndex(uint32_t index)) {
+ return (index + kBitIndexMask) & ~kBitIndexMask;
+ }
+
+ INLINE(MarkBit::CellType* cells()) {
+ return reinterpret_cast<MarkBit::CellType*>(this);
+ }
+
+ INLINE(Address address()) { return reinterpret_cast<Address>(this); }
+
+ INLINE(static Bitmap* FromAddress(Address addr)) {
+ return reinterpret_cast<Bitmap*>(addr);
+ }
+
+ inline MarkBit MarkBitFromIndex(uint32_t index, bool data_only = false) {
+ MarkBit::CellType mask = 1 << (index & kBitIndexMask);
+ MarkBit::CellType* cell = this->cells() + (index >> kBitsPerCellLog2);
+ return MarkBit(cell, mask, data_only);
+ }
+
+ static inline void Clear(MemoryChunk* chunk);
+
+ static void PrintWord(uint32_t word, uint32_t himask = 0) {
+ for (uint32_t mask = 1; mask != 0; mask <<= 1) {
+ if ((mask & himask) != 0) PrintF("[");
+ PrintF((mask & word) ? "1" : "0");
+ if ((mask & himask) != 0) PrintF("]");
+ }
+ }
+
+ class CellPrinter {
+ public:
+ CellPrinter() : seq_start(0), seq_type(0), seq_length(0) {}
+
+ void Print(uint32_t pos, uint32_t cell) {
+ if (cell == seq_type) {
+ seq_length++;
+ return;
+ }
+
+ Flush();
+
+ if (IsSeq(cell)) {
+ seq_start = pos;
+ seq_length = 0;
+ seq_type = cell;
+ return;
+ }
+
+ PrintF("%d: ", pos);
+ PrintWord(cell);
+ PrintF("\n");
+ }
+
+ void Flush() {
+ if (seq_length > 0) {
+ PrintF("%d: %dx%d\n", seq_start, seq_type == 0 ? 0 : 1,
+ seq_length * kBitsPerCell);
+ seq_length = 0;
+ }
+ }
+
+ static bool IsSeq(uint32_t cell) { return cell == 0 || cell == 0xFFFFFFFF; }
+
+ private:
+ uint32_t seq_start;
+ uint32_t seq_type;
+ uint32_t seq_length;
+ };
+
+ void Print() {
+ CellPrinter printer;
+ for (int i = 0; i < CellsCount(); i++) {
+ printer.Print(i, cells()[i]);
+ }
+ printer.Flush();
+ PrintF("\n");
+ }
+
+ bool IsClean() {
+ for (int i = 0; i < CellsCount(); i++) {
+ if (cells()[i] != 0) {
+ return false;
+ }
+ }
+ return true;
+ }
+};
+
+
+class SkipList;
+class SlotsBuffer;
+
+// MemoryChunk represents a memory region owned by a specific space.
+// It is divided into the header and the body. Chunk start is always
+// 1MB aligned. Start of the body is aligned so it can accommodate
+// any heap object.
+class MemoryChunk {
+ public:
+ // Only works if the pointer is in the first kPageSize of the MemoryChunk.
+ static MemoryChunk* FromAddress(Address a) {
+ return reinterpret_cast<MemoryChunk*>(OffsetFrom(a) & ~kAlignmentMask);
+ }
+ static const MemoryChunk* FromAddress(const byte* a) {
+ return reinterpret_cast<const MemoryChunk*>(OffsetFrom(a) &
+ ~kAlignmentMask);
+ }
+
+ // Only works for addresses in pointer spaces, not data or code spaces.
+ static inline MemoryChunk* FromAnyPointerAddress(Heap* heap, Address addr);
+
+ Address address() { return reinterpret_cast<Address>(this); }
+
+ bool is_valid() { return address() != NULL; }
+
+ MemoryChunk* next_chunk() const {
+ return reinterpret_cast<MemoryChunk*>(base::Acquire_Load(&next_chunk_));
+ }
+
+ MemoryChunk* prev_chunk() const {
+ return reinterpret_cast<MemoryChunk*>(base::Acquire_Load(&prev_chunk_));
+ }
+
+ void set_next_chunk(MemoryChunk* next) {
+ base::Release_Store(&next_chunk_, reinterpret_cast<base::AtomicWord>(next));
+ }
+
+ void set_prev_chunk(MemoryChunk* prev) {
+ base::Release_Store(&prev_chunk_, reinterpret_cast<base::AtomicWord>(prev));
+ }
+
+ Space* owner() const {
+ if ((reinterpret_cast<intptr_t>(owner_) & kPageHeaderTagMask) ==
+ kPageHeaderTag) {
+ return reinterpret_cast<Space*>(reinterpret_cast<intptr_t>(owner_) -
+ kPageHeaderTag);
+ } else {
+ return NULL;
+ }
+ }
+
+ void set_owner(Space* space) {
+ DCHECK((reinterpret_cast<intptr_t>(space) & kPageHeaderTagMask) == 0);
+ owner_ = reinterpret_cast<Address>(space) + kPageHeaderTag;
+ DCHECK((reinterpret_cast<intptr_t>(owner_) & kPageHeaderTagMask) ==
+ kPageHeaderTag);
+ }
+
+ base::VirtualMemory* reserved_memory() { return &reservation_; }
+
+ void InitializeReservedMemory() { reservation_.Reset(); }
+
+ void set_reserved_memory(base::VirtualMemory* reservation) {
+ DCHECK_NOT_NULL(reservation);
+ reservation_.TakeControl(reservation);
+ }
+
+ bool scan_on_scavenge() { return IsFlagSet(SCAN_ON_SCAVENGE); }
+ void initialize_scan_on_scavenge(bool scan) {
+ if (scan) {
+ SetFlag(SCAN_ON_SCAVENGE);
+ } else {
+ ClearFlag(SCAN_ON_SCAVENGE);
+ }
+ }
+ inline void set_scan_on_scavenge(bool scan);
+
+ int store_buffer_counter() { return store_buffer_counter_; }
+ void set_store_buffer_counter(int counter) {
+ store_buffer_counter_ = counter;
+ }
+
+ bool Contains(Address addr) {
+ return addr >= area_start() && addr < area_end();
+ }
+
+ // Checks whether addr can be a limit of addresses in this page.
+ // It's a limit if it's in the page, or if it's just after the
+ // last byte of the page.
+ bool ContainsLimit(Address addr) {
+ return addr >= area_start() && addr <= area_end();
+ }
+
+ // Every n write barrier invocations we go to runtime even though
+ // we could have handled it in generated code. This lets us check
+ // whether we have hit the limit and should do some more marking.
+ static const int kWriteBarrierCounterGranularity = 500;
+
+ enum MemoryChunkFlags {
+ IS_EXECUTABLE,
+ ABOUT_TO_BE_FREED,
+ POINTERS_TO_HERE_ARE_INTERESTING,
+ POINTERS_FROM_HERE_ARE_INTERESTING,
+ SCAN_ON_SCAVENGE,
+ IN_FROM_SPACE, // Mutually exclusive with IN_TO_SPACE.
+ IN_TO_SPACE, // All pages in new space has one of these two set.
+ NEW_SPACE_BELOW_AGE_MARK,
+ CONTAINS_ONLY_DATA,
+ EVACUATION_CANDIDATE,
+ RESCAN_ON_EVACUATION,
+
+ // WAS_SWEPT indicates that marking bits have been cleared by the sweeper,
+ // otherwise marking bits are still intact.
+ WAS_SWEPT,
+
+ // Large objects can have a progress bar in their page header. These object
+ // are scanned in increments and will be kept black while being scanned.
+ // Even if the mutator writes to them they will be kept black and a white
+ // to grey transition is performed in the value.
+ HAS_PROGRESS_BAR,
+
+ // Last flag, keep at bottom.
+ NUM_MEMORY_CHUNK_FLAGS
+ };
+
+
+ static const int kPointersToHereAreInterestingMask =
+ 1 << POINTERS_TO_HERE_ARE_INTERESTING;
+
+ static const int kPointersFromHereAreInterestingMask =
+ 1 << POINTERS_FROM_HERE_ARE_INTERESTING;
+
+ static const int kEvacuationCandidateMask = 1 << EVACUATION_CANDIDATE;
+
+ static const int kSkipEvacuationSlotsRecordingMask =
+ (1 << EVACUATION_CANDIDATE) | (1 << RESCAN_ON_EVACUATION) |
+ (1 << IN_FROM_SPACE) | (1 << IN_TO_SPACE);
+
+
+ void SetFlag(int flag) { flags_ |= static_cast<uintptr_t>(1) << flag; }
+
+ void ClearFlag(int flag) { flags_ &= ~(static_cast<uintptr_t>(1) << flag); }
+
+ void SetFlagTo(int flag, bool value) {
+ if (value) {
+ SetFlag(flag);
+ } else {
+ ClearFlag(flag);
+ }
+ }
+
+ bool IsFlagSet(int flag) {
+ return (flags_ & (static_cast<uintptr_t>(1) << flag)) != 0;
+ }
+
+ // Set or clear multiple flags at a time. The flags in the mask
+ // are set to the value in "flags", the rest retain the current value
+ // in flags_.
+ void SetFlags(intptr_t flags, intptr_t mask) {
+ flags_ = (flags_ & ~mask) | (flags & mask);
+ }
+
+ // Return all current flags.
+ intptr_t GetFlags() { return flags_; }
+
+
+ // SWEEPING_DONE - The page state when sweeping is complete or sweeping must
+ // not be performed on that page.
+ // SWEEPING_FINALIZE - A sweeper thread is done sweeping this page and will
+ // not touch the page memory anymore.
+ // SWEEPING_IN_PROGRESS - This page is currently swept by a sweeper thread.
+ // SWEEPING_PENDING - This page is ready for parallel sweeping.
+ enum ParallelSweepingState {
+ SWEEPING_DONE,
+ SWEEPING_FINALIZE,
+ SWEEPING_IN_PROGRESS,
+ SWEEPING_PENDING
+ };
+
+ ParallelSweepingState parallel_sweeping() {
+ return static_cast<ParallelSweepingState>(
+ base::Acquire_Load(¶llel_sweeping_));
+ }
+
+ void set_parallel_sweeping(ParallelSweepingState state) {
+ base::Release_Store(¶llel_sweeping_, state);
+ }
+
+ bool TryParallelSweeping() {
+ return base::Acquire_CompareAndSwap(¶llel_sweeping_, SWEEPING_PENDING,
+ SWEEPING_IN_PROGRESS) ==
+ SWEEPING_PENDING;
+ }
+
+ bool SweepingCompleted() { return parallel_sweeping() <= SWEEPING_FINALIZE; }
+
+ // Manage live byte count (count of bytes known to be live,
+ // because they are marked black).
+ void ResetLiveBytes() {
+ if (FLAG_gc_verbose) {
+ PrintF("ResetLiveBytes:%p:%x->0\n", static_cast<void*>(this),
+ live_byte_count_);
+ }
+ live_byte_count_ = 0;
+ }
+ void IncrementLiveBytes(int by) {
+ if (FLAG_gc_verbose) {
+ printf("UpdateLiveBytes:%p:%x%c=%x->%x\n", static_cast<void*>(this),
+ live_byte_count_, ((by < 0) ? '-' : '+'), ((by < 0) ? -by : by),
+ live_byte_count_ + by);
+ }
+ live_byte_count_ += by;
+ DCHECK_LE(static_cast<unsigned>(live_byte_count_), size_);
+ }
+ int LiveBytes() {
+ DCHECK(static_cast<unsigned>(live_byte_count_) <= size_);
+ return live_byte_count_;
+ }
+
+ int write_barrier_counter() {
+ return static_cast<int>(write_barrier_counter_);
+ }
+
+ void set_write_barrier_counter(int counter) {
+ write_barrier_counter_ = counter;
+ }
+
+ int progress_bar() {
+ DCHECK(IsFlagSet(HAS_PROGRESS_BAR));
+ return progress_bar_;
+ }
+
+ void set_progress_bar(int progress_bar) {
+ DCHECK(IsFlagSet(HAS_PROGRESS_BAR));
+ progress_bar_ = progress_bar;
+ }
+
+ void ResetProgressBar() {
+ if (IsFlagSet(MemoryChunk::HAS_PROGRESS_BAR)) {
+ set_progress_bar(0);
+ ClearFlag(MemoryChunk::HAS_PROGRESS_BAR);
+ }
+ }
+
+ bool IsLeftOfProgressBar(Object** slot) {
+ Address slot_address = reinterpret_cast<Address>(slot);
+ DCHECK(slot_address > this->address());
+ return (slot_address - (this->address() + kObjectStartOffset)) <
+ progress_bar();
+ }
+
+ static void IncrementLiveBytesFromGC(Address address, int by) {
+ MemoryChunk::FromAddress(address)->IncrementLiveBytes(by);
+ }
+
+ static void IncrementLiveBytesFromMutator(Address address, int by);
+
+ static const intptr_t kAlignment =
+ (static_cast<uintptr_t>(1) << kPageSizeBits);
+
+ static const intptr_t kAlignmentMask = kAlignment - 1;
+
+ static const intptr_t kSizeOffset = 0;
+
+ static const intptr_t kLiveBytesOffset =
+ kSizeOffset + kPointerSize + kPointerSize + kPointerSize + kPointerSize +
+ kPointerSize + kPointerSize + kPointerSize + kPointerSize + kIntSize;
+
+ static const size_t kSlotsBufferOffset = kLiveBytesOffset + kIntSize;
+
+ static const size_t kWriteBarrierCounterOffset =
+ kSlotsBufferOffset + kPointerSize + kPointerSize;
+
+ static const size_t kHeaderSize =
+ kWriteBarrierCounterOffset + kPointerSize + kIntSize + kIntSize +
+ kPointerSize + 5 * kPointerSize + kPointerSize + kPointerSize;
+
+ static const int kBodyOffset =
+ CODE_POINTER_ALIGN(kHeaderSize + Bitmap::kSize);
+
+ // The start offset of the object area in a page. Aligned to both maps and
+ // code alignment to be suitable for both. Also aligned to 32 words because
+ // the marking bitmap is arranged in 32 bit chunks.
+ static const int kObjectStartAlignment = 32 * kPointerSize;
+ static const int kObjectStartOffset =
+ kBodyOffset - 1 +
+ (kObjectStartAlignment - (kBodyOffset - 1) % kObjectStartAlignment);
+
+ size_t size() const { return size_; }
+
+ void set_size(size_t size) { size_ = size; }
+
+ void SetArea(Address area_start, Address area_end) {
+ area_start_ = area_start;
+ area_end_ = area_end;
+ }
+
+ Executability executable() {
+ return IsFlagSet(IS_EXECUTABLE) ? EXECUTABLE : NOT_EXECUTABLE;
+ }
+
+ bool ContainsOnlyData() { return IsFlagSet(CONTAINS_ONLY_DATA); }
+
+ bool InNewSpace() {
+ return (flags_ & ((1 << IN_FROM_SPACE) | (1 << IN_TO_SPACE))) != 0;
+ }
+
+ bool InToSpace() { return IsFlagSet(IN_TO_SPACE); }
+
+ bool InFromSpace() { return IsFlagSet(IN_FROM_SPACE); }
+
+ // ---------------------------------------------------------------------
+ // Markbits support
+
+ inline Bitmap* markbits() {
+ return Bitmap::FromAddress(address() + kHeaderSize);
+ }
+
+ void PrintMarkbits() { markbits()->Print(); }
+
+ inline uint32_t AddressToMarkbitIndex(Address addr) {
+ return static_cast<uint32_t>(addr - this->address()) >> kPointerSizeLog2;
+ }
+
+ inline static uint32_t FastAddressToMarkbitIndex(Address addr) {
+ const intptr_t offset = reinterpret_cast<intptr_t>(addr) & kAlignmentMask;
+
+ return static_cast<uint32_t>(offset) >> kPointerSizeLog2;
+ }
+
+ inline Address MarkbitIndexToAddress(uint32_t index) {
+ return this->address() + (index << kPointerSizeLog2);
+ }
+
+ void InsertAfter(MemoryChunk* other);
+ void Unlink();
+
+ inline Heap* heap() const { return heap_; }
+
+ static const int kFlagsOffset = kPointerSize;
+
+ bool IsEvacuationCandidate() { return IsFlagSet(EVACUATION_CANDIDATE); }
+
+ bool ShouldSkipEvacuationSlotRecording() {
+ return (flags_ & kSkipEvacuationSlotsRecordingMask) != 0;
+ }
+
+ inline SkipList* skip_list() { return skip_list_; }
+
+ inline void set_skip_list(SkipList* skip_list) { skip_list_ = skip_list; }
+
+ inline SlotsBuffer* slots_buffer() { return slots_buffer_; }
+
+ inline SlotsBuffer** slots_buffer_address() { return &slots_buffer_; }
+
+ void MarkEvacuationCandidate() {
+ DCHECK(slots_buffer_ == NULL);
+ SetFlag(EVACUATION_CANDIDATE);
+ }
+
+ void ClearEvacuationCandidate() {
+ DCHECK(slots_buffer_ == NULL);
+ ClearFlag(EVACUATION_CANDIDATE);
+ }
+
+ Address area_start() { return area_start_; }
+ Address area_end() { return area_end_; }
+ int area_size() { return static_cast<int>(area_end() - area_start()); }
+ bool CommitArea(size_t requested);
+
+ // Approximate amount of physical memory committed for this chunk.
+ size_t CommittedPhysicalMemory() { return high_water_mark_; }
+
+ static inline void UpdateHighWaterMark(Address mark);
+
+ protected:
+ size_t size_;
+ intptr_t flags_;
+
+ // Start and end of allocatable memory on this chunk.
+ Address area_start_;
+ Address area_end_;
+
+ // If the chunk needs to remember its memory reservation, it is stored here.
+ base::VirtualMemory reservation_;
+ // The identity of the owning space. This is tagged as a failure pointer, but
+ // no failure can be in an object, so this can be distinguished from any entry
+ // in a fixed array.
+ Address owner_;
+ Heap* heap_;
+ // Used by the store buffer to keep track of which pages to mark scan-on-
+ // scavenge.
+ int store_buffer_counter_;
+ // Count of bytes marked black on page.
+ int live_byte_count_;
+ SlotsBuffer* slots_buffer_;
+ SkipList* skip_list_;
+ intptr_t write_barrier_counter_;
+ // Used by the incremental marker to keep track of the scanning progress in
+ // large objects that have a progress bar and are scanned in increments.
+ int progress_bar_;
+ // Assuming the initial allocation on a page is sequential,
+ // count highest number of bytes ever allocated on the page.
+ int high_water_mark_;
+
+ base::AtomicWord parallel_sweeping_;
+
+ // PagedSpace free-list statistics.
+ intptr_t available_in_small_free_list_;
+ intptr_t available_in_medium_free_list_;
+ intptr_t available_in_large_free_list_;
+ intptr_t available_in_huge_free_list_;
+ intptr_t non_available_small_blocks_;
+
+ static MemoryChunk* Initialize(Heap* heap, Address base, size_t size,
+ Address area_start, Address area_end,
+ Executability executable, Space* owner);
+
+ private:
+ // next_chunk_ holds a pointer of type MemoryChunk
+ base::AtomicWord next_chunk_;
+ // prev_chunk_ holds a pointer of type MemoryChunk
+ base::AtomicWord prev_chunk_;
+
+ friend class MemoryAllocator;
+};
+
+
+STATIC_ASSERT(sizeof(MemoryChunk) <= MemoryChunk::kHeaderSize);
+
+
+// -----------------------------------------------------------------------------
+// A page is a memory chunk of a size 1MB. Large object pages may be larger.
+//
+// The only way to get a page pointer is by calling factory methods:
+// Page* p = Page::FromAddress(addr); or
+// Page* p = Page::FromAllocationTop(top);
+class Page : public MemoryChunk {
+ public:
+ // Returns the page containing a given address. The address ranges
+ // from [page_addr .. page_addr + kPageSize[
+ // This only works if the object is in fact in a page. See also MemoryChunk::
+ // FromAddress() and FromAnyAddress().
+ INLINE(static Page* FromAddress(Address a)) {
+ return reinterpret_cast<Page*>(OffsetFrom(a) & ~kPageAlignmentMask);
+ }
+
+ // Returns the page containing an allocation top. Because an allocation
+ // top address can be the upper bound of the page, we need to subtract
+ // it with kPointerSize first. The address ranges from
+ // [page_addr + kObjectStartOffset .. page_addr + kPageSize].
+ INLINE(static Page* FromAllocationTop(Address top)) {
+ Page* p = FromAddress(top - kPointerSize);
+ return p;
+ }
+
+ // Returns the next page in the chain of pages owned by a space.
+ inline Page* next_page();
+ inline Page* prev_page();
+ inline void set_next_page(Page* page);
+ inline void set_prev_page(Page* page);
+
+ // Checks whether an address is page aligned.
+ static bool IsAlignedToPageSize(Address a) {
+ return 0 == (OffsetFrom(a) & kPageAlignmentMask);
+ }
+
+ // Returns the offset of a given address to this page.
+ INLINE(int Offset(Address a)) {
+ int offset = static_cast<int>(a - address());
+ return offset;
+ }
+
+ // Returns the address for a given offset to the this page.
+ Address OffsetToAddress(int offset) {
+ DCHECK_PAGE_OFFSET(offset);
+ return address() + offset;
+ }
+
+ // ---------------------------------------------------------------------
+
+ // Page size in bytes. This must be a multiple of the OS page size.
+ static const int kPageSize = 1 << kPageSizeBits;
+
+ // Maximum object size that fits in a page. Objects larger than that size
+ // are allocated in large object space and are never moved in memory. This
+ // also applies to new space allocation, since objects are never migrated
+ // from new space to large object space. Takes double alignment into account.
+ static const int kMaxRegularHeapObjectSize = kPageSize - kObjectStartOffset;
+
+ // Page size mask.
+ static const intptr_t kPageAlignmentMask = (1 << kPageSizeBits) - 1;
+
+ inline void ClearGCFields();
+
+ static inline Page* Initialize(Heap* heap, MemoryChunk* chunk,
+ Executability executable, PagedSpace* owner);
+
+ void InitializeAsAnchor(PagedSpace* owner);
+
+ bool WasSwept() { return IsFlagSet(WAS_SWEPT); }
+ void SetWasSwept() { SetFlag(WAS_SWEPT); }
+ void ClearWasSwept() { ClearFlag(WAS_SWEPT); }
+
+ void ResetFreeListStatistics();
+
+#define FRAGMENTATION_STATS_ACCESSORS(type, name) \
+ type name() { return name##_; } \
+ void set_##name(type name) { name##_ = name; } \
+ void add_##name(type name) { name##_ += name; }
+
+ FRAGMENTATION_STATS_ACCESSORS(intptr_t, non_available_small_blocks)
+ FRAGMENTATION_STATS_ACCESSORS(intptr_t, available_in_small_free_list)
+ FRAGMENTATION_STATS_ACCESSORS(intptr_t, available_in_medium_free_list)
+ FRAGMENTATION_STATS_ACCESSORS(intptr_t, available_in_large_free_list)
+ FRAGMENTATION_STATS_ACCESSORS(intptr_t, available_in_huge_free_list)
+
+#undef FRAGMENTATION_STATS_ACCESSORS
+
+#ifdef DEBUG
+ void Print();
+#endif // DEBUG
+
+ friend class MemoryAllocator;
+};
+
+
+STATIC_ASSERT(sizeof(Page) <= MemoryChunk::kHeaderSize);
+
+
+class LargePage : public MemoryChunk {
+ public:
+ HeapObject* GetObject() { return HeapObject::FromAddress(area_start()); }
+
+ inline LargePage* next_page() const {
+ return static_cast<LargePage*>(next_chunk());
+ }
+
+ inline void set_next_page(LargePage* page) { set_next_chunk(page); }
+
+ private:
+ static inline LargePage* Initialize(Heap* heap, MemoryChunk* chunk);
+
+ friend class MemoryAllocator;
+};
+
+STATIC_ASSERT(sizeof(LargePage) <= MemoryChunk::kHeaderSize);
+
+// ----------------------------------------------------------------------------
+// Space is the abstract superclass for all allocation spaces.
+class Space : public Malloced {
+ public:
+ Space(Heap* heap, AllocationSpace id, Executability executable)
+ : heap_(heap), id_(id), executable_(executable) {}
+
+ virtual ~Space() {}
+
+ Heap* heap() const { return heap_; }
+
+ // Does the space need executable memory?
+ Executability executable() { return executable_; }
+
+ // Identity used in error reporting.
+ AllocationSpace identity() { return id_; }
+
+ // Returns allocated size.
+ virtual intptr_t Size() = 0;
+
+ // Returns size of objects. Can differ from the allocated size
+ // (e.g. see LargeObjectSpace).
+ virtual intptr_t SizeOfObjects() { return Size(); }
+
+ virtual int RoundSizeDownToObjectAlignment(int size) {
+ if (id_ == CODE_SPACE) {
+ return RoundDown(size, kCodeAlignment);
+ } else {
+ return RoundDown(size, kPointerSize);
+ }
+ }
+
+#ifdef DEBUG
+ virtual void Print() = 0;
+#endif
+
+ private:
+ Heap* heap_;
+ AllocationSpace id_;
+ Executability executable_;
+};
+
+
+// ----------------------------------------------------------------------------
+// All heap objects containing executable code (code objects) must be allocated
+// from a 2 GB range of memory, so that they can call each other using 32-bit
+// displacements. This happens automatically on 32-bit platforms, where 32-bit
+// displacements cover the entire 4GB virtual address space. On 64-bit
+// platforms, we support this using the CodeRange object, which reserves and
+// manages a range of virtual memory.
+class CodeRange {
+ public:
+ explicit CodeRange(Isolate* isolate);
+ ~CodeRange() { TearDown(); }
+
+ // Reserves a range of virtual memory, but does not commit any of it.
+ // Can only be called once, at heap initialization time.
+ // Returns false on failure.
+ bool SetUp(size_t requested_size);
+
+ // Frees the range of virtual memory, and frees the data structures used to
+ // manage it.
+ void TearDown();
+
+ bool valid() { return code_range_ != NULL; }
+ Address start() {
+ DCHECK(valid());
+ return static_cast<Address>(code_range_->address());
+ }
+ bool contains(Address address) {
+ if (!valid()) return false;
+ Address start = static_cast<Address>(code_range_->address());
+ return start <= address && address < start + code_range_->size();
+ }
+
+ // Allocates a chunk of memory from the large-object portion of
+ // the code range. On platforms with no separate code range, should
+ // not be called.
+ MUST_USE_RESULT Address AllocateRawMemory(const size_t requested_size,
+ const size_t commit_size,
+ size_t* allocated);
+ bool CommitRawMemory(Address start, size_t length);
+ bool UncommitRawMemory(Address start, size_t length);
+ void FreeRawMemory(Address buf, size_t length);
+
+ private:
+ Isolate* isolate_;
+
+ // The reserved range of virtual memory that all code objects are put in.
+ base::VirtualMemory* code_range_;
+ // Plain old data class, just a struct plus a constructor.
+ class FreeBlock {
+ public:
+ FreeBlock(Address start_arg, size_t size_arg)
+ : start(start_arg), size(size_arg) {
+ DCHECK(IsAddressAligned(start, MemoryChunk::kAlignment));
+ DCHECK(size >= static_cast<size_t>(Page::kPageSize));
+ }
+ FreeBlock(void* start_arg, size_t size_arg)
+ : start(static_cast<Address>(start_arg)), size(size_arg) {
+ DCHECK(IsAddressAligned(start, MemoryChunk::kAlignment));
+ DCHECK(size >= static_cast<size_t>(Page::kPageSize));
+ }
+
+ Address start;
+ size_t size;
+ };
+
+ // Freed blocks of memory are added to the free list. When the allocation
+ // list is exhausted, the free list is sorted and merged to make the new
+ // allocation list.
+ List<FreeBlock> free_list_;
+ // Memory is allocated from the free blocks on the allocation list.
+ // The block at current_allocation_block_index_ is the current block.
+ List<FreeBlock> allocation_list_;
+ int current_allocation_block_index_;
+
+ // Finds a block on the allocation list that contains at least the
+ // requested amount of memory. If none is found, sorts and merges
+ // the existing free memory blocks, and searches again.
+ // If none can be found, returns false.
+ bool GetNextAllocationBlock(size_t requested);
+ // Compares the start addresses of two free blocks.
+ static int CompareFreeBlockAddress(const FreeBlock* left,
+ const FreeBlock* right);
+
+ DISALLOW_COPY_AND_ASSIGN(CodeRange);
+};
+
+
+class SkipList {
+ public:
+ SkipList() { Clear(); }
+
+ void Clear() {
+ for (int idx = 0; idx < kSize; idx++) {
+ starts_[idx] = reinterpret_cast<Address>(-1);
+ }
+ }
+
+ Address StartFor(Address addr) { return starts_[RegionNumber(addr)]; }
+
+ void AddObject(Address addr, int size) {
+ int start_region = RegionNumber(addr);
+ int end_region = RegionNumber(addr + size - kPointerSize);
+ for (int idx = start_region; idx <= end_region; idx++) {
+ if (starts_[idx] > addr) starts_[idx] = addr;
+ }
+ }
+
+ static inline int RegionNumber(Address addr) {
+ return (OffsetFrom(addr) & Page::kPageAlignmentMask) >> kRegionSizeLog2;
+ }
+
+ static void Update(Address addr, int size) {
+ Page* page = Page::FromAddress(addr);
+ SkipList* list = page->skip_list();
+ if (list == NULL) {
+ list = new SkipList();
+ page->set_skip_list(list);
+ }
+
+ list->AddObject(addr, size);
+ }
+
+ private:
+ static const int kRegionSizeLog2 = 13;
+ static const int kRegionSize = 1 << kRegionSizeLog2;
+ static const int kSize = Page::kPageSize / kRegionSize;
+
+ STATIC_ASSERT(Page::kPageSize % kRegionSize == 0);
+
+ Address starts_[kSize];
+};
+
+
+// ----------------------------------------------------------------------------
+// A space acquires chunks of memory from the operating system. The memory
+// allocator allocated and deallocates pages for the paged heap spaces and large
+// pages for large object space.
+//
+// Each space has to manage it's own pages.
+//
+class MemoryAllocator {
+ public:
+ explicit MemoryAllocator(Isolate* isolate);
+
+ // Initializes its internal bookkeeping structures.
+ // Max capacity of the total space and executable memory limit.
+ bool SetUp(intptr_t max_capacity, intptr_t capacity_executable);
+
+ void TearDown();
+
+ Page* AllocatePage(intptr_t size, PagedSpace* owner,
+ Executability executable);
+
+ LargePage* AllocateLargePage(intptr_t object_size, Space* owner,
+ Executability executable);
+
+ void Free(MemoryChunk* chunk);
+
+ // Returns the maximum available bytes of heaps.
+ intptr_t Available() { return capacity_ < size_ ? 0 : capacity_ - size_; }
+
+ // Returns allocated spaces in bytes.
+ intptr_t Size() { return size_; }
+
+ // Returns the maximum available executable bytes of heaps.
+ intptr_t AvailableExecutable() {
+ if (capacity_executable_ < size_executable_) return 0;
+ return capacity_executable_ - size_executable_;
+ }
+
+ // Returns allocated executable spaces in bytes.
+ intptr_t SizeExecutable() { return size_executable_; }
+
+ // Returns maximum available bytes that the old space can have.
+ intptr_t MaxAvailable() {
+ return (Available() / Page::kPageSize) * Page::kMaxRegularHeapObjectSize;
+ }
+
+ // Returns an indication of whether a pointer is in a space that has
+ // been allocated by this MemoryAllocator.
+ V8_INLINE bool IsOutsideAllocatedSpace(const void* address) const {
+ return address < lowest_ever_allocated_ ||
+ address >= highest_ever_allocated_;
+ }
+
+#ifdef DEBUG
+ // Reports statistic info of the space.
+ void ReportStatistics();
+#endif
+
+ // Returns a MemoryChunk in which the memory region from commit_area_size to
+ // reserve_area_size of the chunk area is reserved but not committed, it
+ // could be committed later by calling MemoryChunk::CommitArea.
+ MemoryChunk* AllocateChunk(intptr_t reserve_area_size,
+ intptr_t commit_area_size,
+ Executability executable, Space* space);
+
+ Address ReserveAlignedMemory(size_t requested, size_t alignment,
+ base::VirtualMemory* controller);
+ Address AllocateAlignedMemory(size_t reserve_size, size_t commit_size,
+ size_t alignment, Executability executable,
+ base::VirtualMemory* controller);
+
+ bool CommitMemory(Address addr, size_t size, Executability executable);
+
+ void FreeMemory(base::VirtualMemory* reservation, Executability executable);
+ void FreeMemory(Address addr, size_t size, Executability executable);
+
+ // Commit a contiguous block of memory from the initial chunk. Assumes that
+ // the address is not NULL, the size is greater than zero, and that the
+ // block is contained in the initial chunk. Returns true if it succeeded
+ // and false otherwise.
+ bool CommitBlock(Address start, size_t size, Executability executable);
+
+ // Uncommit a contiguous block of memory [start..(start+size)[.
+ // start is not NULL, the size is greater than zero, and the
+ // block is contained in the initial chunk. Returns true if it succeeded
+ // and false otherwise.
+ bool UncommitBlock(Address start, size_t size);
+
+ // Zaps a contiguous block of memory [start..(start+size)[ thus
+ // filling it up with a recognizable non-NULL bit pattern.
+ void ZapBlock(Address start, size_t size);
+
+ void PerformAllocationCallback(ObjectSpace space, AllocationAction action,
+ size_t size);
+
+ void AddMemoryAllocationCallback(MemoryAllocationCallback callback,
+ ObjectSpace space, AllocationAction action);
+
+ void RemoveMemoryAllocationCallback(MemoryAllocationCallback callback);
+
+ bool MemoryAllocationCallbackRegistered(MemoryAllocationCallback callback);
+
+ static int CodePageGuardStartOffset();
+
+ static int CodePageGuardSize();
+
+ static int CodePageAreaStartOffset();
+
+ static int CodePageAreaEndOffset();
+
+ static int CodePageAreaSize() {
+ return CodePageAreaEndOffset() - CodePageAreaStartOffset();
+ }
+
+ MUST_USE_RESULT bool CommitExecutableMemory(base::VirtualMemory* vm,
+ Address start, size_t commit_size,
+ size_t reserved_size);
+
+ private:
+ Isolate* isolate_;
+
+ // Maximum space size in bytes.
+ size_t capacity_;
+ // Maximum subset of capacity_ that can be executable
+ size_t capacity_executable_;
+
+ // Allocated space size in bytes.
+ size_t size_;
+ // Allocated executable space size in bytes.
+ size_t size_executable_;
+
+ // We keep the lowest and highest addresses allocated as a quick way
+ // of determining that pointers are outside the heap. The estimate is
+ // conservative, i.e. not all addrsses in 'allocated' space are allocated
+ // to our heap. The range is [lowest, highest[, inclusive on the low end
+ // and exclusive on the high end.
+ void* lowest_ever_allocated_;
+ void* highest_ever_allocated_;
+
+ struct MemoryAllocationCallbackRegistration {
+ MemoryAllocationCallbackRegistration(MemoryAllocationCallback callback,
+ ObjectSpace space,
+ AllocationAction action)
+ : callback(callback), space(space), action(action) {}
+ MemoryAllocationCallback callback;
+ ObjectSpace space;
+ AllocationAction action;
+ };
+
+ // A List of callback that are triggered when memory is allocated or free'd
+ List<MemoryAllocationCallbackRegistration> memory_allocation_callbacks_;
+
+ // Initializes pages in a chunk. Returns the first page address.
+ // This function and GetChunkId() are provided for the mark-compact
+ // collector to rebuild page headers in the from space, which is
+ // used as a marking stack and its page headers are destroyed.
+ Page* InitializePagesInChunk(int chunk_id, int pages_in_chunk,
+ PagedSpace* owner);
+
+ void UpdateAllocatedSpaceLimits(void* low, void* high) {
+ lowest_ever_allocated_ = Min(lowest_ever_allocated_, low);
+ highest_ever_allocated_ = Max(highest_ever_allocated_, high);
+ }
+
+ DISALLOW_IMPLICIT_CONSTRUCTORS(MemoryAllocator);
+};
+
+
+// -----------------------------------------------------------------------------
+// Interface for heap object iterator to be implemented by all object space
+// object iterators.
+//
+// NOTE: The space specific object iterators also implements the own next()
+// method which is used to avoid using virtual functions
+// iterating a specific space.
+
+class ObjectIterator : public Malloced {
+ public:
+ virtual ~ObjectIterator() {}
+
+ virtual HeapObject* next_object() = 0;
+};
+
+
+// -----------------------------------------------------------------------------
+// Heap object iterator in new/old/map spaces.
+//
+// A HeapObjectIterator iterates objects from the bottom of the given space
+// to its top or from the bottom of the given page to its top.
+//
+// If objects are allocated in the page during iteration the iterator may
+// or may not iterate over those objects. The caller must create a new
+// iterator in order to be sure to visit these new objects.
+class HeapObjectIterator : public ObjectIterator {
+ public:
+ // Creates a new object iterator in a given space.
+ // If the size function is not given, the iterator calls the default
+ // Object::Size().
+ explicit HeapObjectIterator(PagedSpace* space);
+ HeapObjectIterator(PagedSpace* space, HeapObjectCallback size_func);
+ HeapObjectIterator(Page* page, HeapObjectCallback size_func);
+
+ // Advance to the next object, skipping free spaces and other fillers and
+ // skipping the special garbage section of which there is one per space.
+ // Returns NULL when the iteration has ended.
+ inline HeapObject* Next() {
+ do {
+ HeapObject* next_obj = FromCurrentPage();
+ if (next_obj != NULL) return next_obj;
+ } while (AdvanceToNextPage());
+ return NULL;
+ }
+
+ virtual HeapObject* next_object() { return Next(); }
+
+ private:
+ enum PageMode { kOnePageOnly, kAllPagesInSpace };
+
+ Address cur_addr_; // Current iteration point.
+ Address cur_end_; // End iteration point.
+ HeapObjectCallback size_func_; // Size function or NULL.
+ PagedSpace* space_;
+ PageMode page_mode_;
+
+ // Fast (inlined) path of next().
+ inline HeapObject* FromCurrentPage();
+
+ // Slow path of next(), goes into the next page. Returns false if the
+ // iteration has ended.
+ bool AdvanceToNextPage();
+
+ // Initializes fields.
+ inline void Initialize(PagedSpace* owner, Address start, Address end,
+ PageMode mode, HeapObjectCallback size_func);
+};
+
+
+// -----------------------------------------------------------------------------
+// A PageIterator iterates the pages in a paged space.
+
+class PageIterator BASE_EMBEDDED {
+ public:
+ explicit inline PageIterator(PagedSpace* space);
+
+ inline bool has_next();
+ inline Page* next();
+
+ private:
+ PagedSpace* space_;
+ Page* prev_page_; // Previous page returned.
+ // Next page that will be returned. Cached here so that we can use this
+ // iterator for operations that deallocate pages.
+ Page* next_page_;
+};
+
+
+// -----------------------------------------------------------------------------
+// A space has a circular list of pages. The next page can be accessed via
+// Page::next_page() call.
+
+// An abstraction of allocation and relocation pointers in a page-structured
+// space.
+class AllocationInfo {
+ public:
+ AllocationInfo() : top_(NULL), limit_(NULL) {}
+
+ INLINE(void set_top(Address top)) {
+ SLOW_DCHECK(top == NULL ||
+ (reinterpret_cast<intptr_t>(top) & HeapObjectTagMask()) == 0);
+ top_ = top;
+ }
+
+ INLINE(Address top()) const {
+ SLOW_DCHECK(top_ == NULL ||
+ (reinterpret_cast<intptr_t>(top_) & HeapObjectTagMask()) == 0);
+ return top_;
+ }
+
+ Address* top_address() { return &top_; }
+
+ INLINE(void set_limit(Address limit)) {
+ SLOW_DCHECK(limit == NULL ||
+ (reinterpret_cast<intptr_t>(limit) & HeapObjectTagMask()) == 0);
+ limit_ = limit;
+ }
+
+ INLINE(Address limit()) const {
+ SLOW_DCHECK(limit_ == NULL ||
+ (reinterpret_cast<intptr_t>(limit_) & HeapObjectTagMask()) ==
+ 0);
+ return limit_;
+ }
+
+ Address* limit_address() { return &limit_; }
+
+#ifdef DEBUG
+ bool VerifyPagedAllocation() {
+ return (Page::FromAllocationTop(top_) == Page::FromAllocationTop(limit_)) &&
+ (top_ <= limit_);
+ }
+#endif
+
+ private:
+ // Current allocation top.
+ Address top_;
+ // Current allocation limit.
+ Address limit_;
+};
+
+
+// An abstraction of the accounting statistics of a page-structured space.
+// The 'capacity' of a space is the number of object-area bytes (i.e., not
+// including page bookkeeping structures) currently in the space. The 'size'
+// of a space is the number of allocated bytes, the 'waste' in the space is
+// the number of bytes that are not allocated and not available to
+// allocation without reorganizing the space via a GC (e.g. small blocks due
+// to internal fragmentation, top of page areas in map space), and the bytes
+// 'available' is the number of unallocated bytes that are not waste. The
+// capacity is the sum of size, waste, and available.
+//
+// The stats are only set by functions that ensure they stay balanced. These
+// functions increase or decrease one of the non-capacity stats in
+// conjunction with capacity, or else they always balance increases and
+// decreases to the non-capacity stats.
+class AllocationStats BASE_EMBEDDED {
+ public:
+ AllocationStats() { Clear(); }
+
+ // Zero out all the allocation statistics (i.e., no capacity).
+ void Clear() {
+ capacity_ = 0;
+ max_capacity_ = 0;
+ size_ = 0;
+ waste_ = 0;
+ }
+
+ void ClearSizeWaste() {
+ size_ = capacity_;
+ waste_ = 0;
+ }
+
+ // Reset the allocation statistics (i.e., available = capacity with no
+ // wasted or allocated bytes).
+ void Reset() {
+ size_ = 0;
+ waste_ = 0;
+ }
+
+ // Accessors for the allocation statistics.
+ intptr_t Capacity() { return capacity_; }
+ intptr_t MaxCapacity() { return max_capacity_; }
+ intptr_t Size() { return size_; }
+ intptr_t Waste() { return waste_; }
+
+ // Grow the space by adding available bytes. They are initially marked as
+ // being in use (part of the size), but will normally be immediately freed,
+ // putting them on the free list and removing them from size_.
+ void ExpandSpace(int size_in_bytes) {
+ capacity_ += size_in_bytes;
+ size_ += size_in_bytes;
+ if (capacity_ > max_capacity_) {
+ max_capacity_ = capacity_;
+ }
+ DCHECK(size_ >= 0);
+ }
+
+ // Shrink the space by removing available bytes. Since shrinking is done
+ // during sweeping, bytes have been marked as being in use (part of the size)
+ // and are hereby freed.
+ void ShrinkSpace(int size_in_bytes) {
+ capacity_ -= size_in_bytes;
+ size_ -= size_in_bytes;
+ DCHECK(size_ >= 0);
+ }
+
+ // Allocate from available bytes (available -> size).
+ void AllocateBytes(intptr_t size_in_bytes) {
+ size_ += size_in_bytes;
+ DCHECK(size_ >= 0);
+ }
+
+ // Free allocated bytes, making them available (size -> available).
+ void DeallocateBytes(intptr_t size_in_bytes) {
+ size_ -= size_in_bytes;
+ DCHECK(size_ >= 0);
+ }
+
+ // Waste free bytes (available -> waste).
+ void WasteBytes(int size_in_bytes) {
+ DCHECK(size_in_bytes >= 0);
+ waste_ += size_in_bytes;
+ }
+
+ private:
+ intptr_t capacity_;
+ intptr_t max_capacity_;
+ intptr_t size_;
+ intptr_t waste_;
+};
+
+
+// -----------------------------------------------------------------------------
+// Free lists for old object spaces
+//
+// Free-list nodes are free blocks in the heap. They look like heap objects
+// (free-list node pointers have the heap object tag, and they have a map like
+// a heap object). They have a size and a next pointer. The next pointer is
+// the raw address of the next free list node (or NULL).
+class FreeListNode : public HeapObject {
+ public:
+ // Obtain a free-list node from a raw address. This is not a cast because
+ // it does not check nor require that the first word at the address is a map
+ // pointer.
+ static FreeListNode* FromAddress(Address address) {
+ return reinterpret_cast<FreeListNode*>(HeapObject::FromAddress(address));
+ }
+
+ static inline bool IsFreeListNode(HeapObject* object);
+
+ // Set the size in bytes, which can be read with HeapObject::Size(). This
+ // function also writes a map to the first word of the block so that it
+ // looks like a heap object to the garbage collector and heap iteration
+ // functions.
+ void set_size(Heap* heap, int size_in_bytes);
+
+ // Accessors for the next field.
+ inline FreeListNode* next();
+ inline FreeListNode** next_address();
+ inline void set_next(FreeListNode* next);
+
+ inline void Zap();
+
+ static inline FreeListNode* cast(Object* object) {
+ return reinterpret_cast<FreeListNode*>(object);
+ }
+
+ private:
+ static const int kNextOffset = POINTER_SIZE_ALIGN(FreeSpace::kHeaderSize);
+
+ DISALLOW_IMPLICIT_CONSTRUCTORS(FreeListNode);
+};
+
+
+// The free list category holds a pointer to the top element and a pointer to
+// the end element of the linked list of free memory blocks.
+class FreeListCategory {
+ public:
+ FreeListCategory() : top_(0), end_(NULL), available_(0) {}
+
+ intptr_t Concatenate(FreeListCategory* category);
+
+ void Reset();
+
+ void Free(FreeListNode* node, int size_in_bytes);
+
+ FreeListNode* PickNodeFromList(int* node_size);
+ FreeListNode* PickNodeFromList(int size_in_bytes, int* node_size);
+
+ intptr_t EvictFreeListItemsInList(Page* p);
+ bool ContainsPageFreeListItemsInList(Page* p);
+
+ void RepairFreeList(Heap* heap);
+
+ FreeListNode* top() const {
+ return reinterpret_cast<FreeListNode*>(base::NoBarrier_Load(&top_));
+ }
+
+ void set_top(FreeListNode* top) {
+ base::NoBarrier_Store(&top_, reinterpret_cast<base::AtomicWord>(top));
+ }
+
+ FreeListNode** GetEndAddress() { return &end_; }
+ FreeListNode* end() const { return end_; }
+ void set_end(FreeListNode* end) { end_ = end; }
+
+ int* GetAvailableAddress() { return &available_; }
+ int available() const { return available_; }
+ void set_available(int available) { available_ = available; }
+
+ base::Mutex* mutex() { return &mutex_; }
+
+ bool IsEmpty() { return top() == 0; }
+
+#ifdef DEBUG
+ intptr_t SumFreeList();
+ int FreeListLength();
+#endif
+
+ private:
+ // top_ points to the top FreeListNode* in the free list category.
+ base::AtomicWord top_;
+ FreeListNode* end_;
+ base::Mutex mutex_;
+
+ // Total available bytes in all blocks of this free list category.
+ int available_;
+};
+
+
+// The free list for the old space. The free list is organized in such a way
+// as to encourage objects allocated around the same time to be near each
+// other. The normal way to allocate is intended to be by bumping a 'top'
+// pointer until it hits a 'limit' pointer. When the limit is hit we need to
+// find a new space to allocate from. This is done with the free list, which
+// is divided up into rough categories to cut down on waste. Having finer
+// categories would scatter allocation more.
+
+// The old space free list is organized in categories.
+// 1-31 words: Such small free areas are discarded for efficiency reasons.
+// They can be reclaimed by the compactor. However the distance between top
+// and limit may be this small.
+// 32-255 words: There is a list of spaces this large. It is used for top and
+// limit when the object we need to allocate is 1-31 words in size. These
+// spaces are called small.
+// 256-2047 words: There is a list of spaces this large. It is used for top and
+// limit when the object we need to allocate is 32-255 words in size. These
+// spaces are called medium.
+// 1048-16383 words: There is a list of spaces this large. It is used for top
+// and limit when the object we need to allocate is 256-2047 words in size.
+// These spaces are call large.
+// At least 16384 words. This list is for objects of 2048 words or larger.
+// Empty pages are added to this list. These spaces are called huge.
+class FreeList {
+ public:
+ explicit FreeList(PagedSpace* owner);
+
+ intptr_t Concatenate(FreeList* free_list);
+
+ // Clear the free list.
+ void Reset();
+
+ // Return the number of bytes available on the free list.
+ intptr_t available() {
+ return small_list_.available() + medium_list_.available() +
+ large_list_.available() + huge_list_.available();
+ }
+
+ // Place a node on the free list. The block of size 'size_in_bytes'
+ // starting at 'start' is placed on the free list. The return value is the
+ // number of bytes that have been lost due to internal fragmentation by
+ // freeing the block. Bookkeeping information will be written to the block,
+ // i.e., its contents will be destroyed. The start address should be word
+ // aligned, and the size should be a non-zero multiple of the word size.
+ int Free(Address start, int size_in_bytes);
+
+ // This method returns how much memory can be allocated after freeing
+ // maximum_freed memory.
+ static inline int GuaranteedAllocatable(int maximum_freed) {
+ if (maximum_freed < kSmallListMin) {
+ return 0;
+ } else if (maximum_freed <= kSmallListMax) {
+ return kSmallAllocationMax;
+ } else if (maximum_freed <= kMediumListMax) {
+ return kMediumAllocationMax;
+ } else if (maximum_freed <= kLargeListMax) {
+ return kLargeAllocationMax;
+ }
+ return maximum_freed;
+ }
+
+ // Allocate a block of size 'size_in_bytes' from the free list. The block
+ // is unitialized. A failure is returned if no block is available. The
+ // number of bytes lost to fragmentation is returned in the output parameter
+ // 'wasted_bytes'. The size should be a non-zero multiple of the word size.
+ MUST_USE_RESULT HeapObject* Allocate(int size_in_bytes);
+
+ bool IsEmpty() {
+ return small_list_.IsEmpty() && medium_list_.IsEmpty() &&
+ large_list_.IsEmpty() && huge_list_.IsEmpty();
+ }
+
+#ifdef DEBUG
+ void Zap();
+ intptr_t SumFreeLists();
+ bool IsVeryLong();
+#endif
+
+ // Used after booting the VM.
+ void RepairLists(Heap* heap);
+
+ intptr_t EvictFreeListItems(Page* p);
+ bool ContainsPageFreeListItems(Page* p);
+
+ FreeListCategory* small_list() { return &small_list_; }
+ FreeListCategory* medium_list() { return &medium_list_; }
+ FreeListCategory* large_list() { return &large_list_; }
+ FreeListCategory* huge_list() { return &huge_list_; }
+
+ private:
+ // The size range of blocks, in bytes.
+ static const int kMinBlockSize = 3 * kPointerSize;
+ static const int kMaxBlockSize = Page::kMaxRegularHeapObjectSize;
+
+ FreeListNode* FindNodeFor(int size_in_bytes, int* node_size);
+
+ PagedSpace* owner_;
+ Heap* heap_;
+
+ static const int kSmallListMin = 0x20 * kPointerSize;
+ static const int kSmallListMax = 0xff * kPointerSize;
+ static const int kMediumListMax = 0x7ff * kPointerSize;
+ static const int kLargeListMax = 0x3fff * kPointerSize;
+ static const int kSmallAllocationMax = kSmallListMin - kPointerSize;
+ static const int kMediumAllocationMax = kSmallListMax;
+ static const int kLargeAllocationMax = kMediumListMax;
+ FreeListCategory small_list_;
+ FreeListCategory medium_list_;
+ FreeListCategory large_list_;
+ FreeListCategory huge_list_;
+
+ DISALLOW_IMPLICIT_CONSTRUCTORS(FreeList);
+};
+
+
+class AllocationResult {
+ public:
+ // Implicit constructor from Object*.
+ AllocationResult(Object* object) // NOLINT
+ : object_(object),
+ retry_space_(INVALID_SPACE) {}
+
+ AllocationResult() : object_(NULL), retry_space_(INVALID_SPACE) {}
+
+ static inline AllocationResult Retry(AllocationSpace space = NEW_SPACE) {
+ return AllocationResult(space);
+ }
+
+ inline bool IsRetry() { return retry_space_ != INVALID_SPACE; }
+
+ template <typename T>
+ bool To(T** obj) {
+ if (IsRetry()) return false;
+ *obj = T::cast(object_);
+ return true;
+ }
+
+ Object* ToObjectChecked() {
+ CHECK(!IsRetry());
+ return object_;
+ }
+
+ AllocationSpace RetrySpace() {
+ DCHECK(IsRetry());
+ return retry_space_;
+ }
+
+ private:
+ explicit AllocationResult(AllocationSpace space)
+ : object_(NULL), retry_space_(space) {}
+
+ Object* object_;
+ AllocationSpace retry_space_;
+};
+
+
+class PagedSpace : public Space {
+ public:
+ // Creates a space with a maximum capacity, and an id.
+ PagedSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id,
+ Executability executable);
+
+ virtual ~PagedSpace() {}
+
+ // Set up the space using the given address range of virtual memory (from
+ // the memory allocator's initial chunk) if possible. If the block of
+ // addresses is not big enough to contain a single page-aligned page, a
+ // fresh chunk will be allocated.
+ bool SetUp();
+
+ // Returns true if the space has been successfully set up and not
+ // subsequently torn down.
+ bool HasBeenSetUp();
+
+ // Cleans up the space, frees all pages in this space except those belonging
+ // to the initial chunk, uncommits addresses in the initial chunk.
+ void TearDown();
+
+ // Checks whether an object/address is in this space.
+ inline bool Contains(Address a);
+ bool Contains(HeapObject* o) { return Contains(o->address()); }
+
+ // Given an address occupied by a live object, return that object if it is
+ // in this space, or a Smi if it is not. The implementation iterates over
+ // objects in the page containing the address, the cost is linear in the
+ // number of objects in the page. It may be slow.
+ Object* FindObject(Address addr);
+
+ // During boot the free_space_map is created, and afterwards we may need
+ // to write it into the free list nodes that were already created.
+ void RepairFreeListsAfterBoot();
+
+ // Prepares for a mark-compact GC.
+ void PrepareForMarkCompact();
+
+ // Current capacity without growing (Size() + Available()).
+ intptr_t Capacity() { return accounting_stats_.Capacity(); }
+
+ // Total amount of memory committed for this space. For paged
+ // spaces this equals the capacity.
+ intptr_t CommittedMemory() { return Capacity(); }
+
+ // The maximum amount of memory ever committed for this space.
+ intptr_t MaximumCommittedMemory() { return accounting_stats_.MaxCapacity(); }
+
+ // Approximate amount of physical memory committed for this space.
+ size_t CommittedPhysicalMemory();
+
+ struct SizeStats {
+ intptr_t Total() {
+ return small_size_ + medium_size_ + large_size_ + huge_size_;
+ }
+
+ intptr_t small_size_;
+ intptr_t medium_size_;
+ intptr_t large_size_;
+ intptr_t huge_size_;
+ };
+
+ void ObtainFreeListStatistics(Page* p, SizeStats* sizes);
+ void ResetFreeListStatistics();
+
+ // Sets the capacity, the available space and the wasted space to zero.
+ // The stats are rebuilt during sweeping by adding each page to the
+ // capacity and the size when it is encountered. As free spaces are
+ // discovered during the sweeping they are subtracted from the size and added
+ // to the available and wasted totals.
+ void ClearStats() {
+ accounting_stats_.ClearSizeWaste();
+ ResetFreeListStatistics();
+ }
+
+ // Increases the number of available bytes of that space.
+ void AddToAccountingStats(intptr_t bytes) {
+ accounting_stats_.DeallocateBytes(bytes);
+ }
+
+ // Available bytes without growing. These are the bytes on the free list.
+ // The bytes in the linear allocation area are not included in this total
+ // because updating the stats would slow down allocation. New pages are
+ // immediately added to the free list so they show up here.
+ intptr_t Available() { return free_list_.available(); }
+
+ // Allocated bytes in this space. Garbage bytes that were not found due to
+ // concurrent sweeping are counted as being allocated! The bytes in the
+ // current linear allocation area (between top and limit) are also counted
+ // here.
+ virtual intptr_t Size() { return accounting_stats_.Size(); }
+
+ // As size, but the bytes in lazily swept pages are estimated and the bytes
+ // in the current linear allocation area are not included.
+ virtual intptr_t SizeOfObjects();
+
+ // Wasted bytes in this space. These are just the bytes that were thrown away
+ // due to being too small to use for allocation. They do not include the
+ // free bytes that were not found at all due to lazy sweeping.
+ virtual intptr_t Waste() { return accounting_stats_.Waste(); }
+
+ // Returns the allocation pointer in this space.
+ Address top() { return allocation_info_.top(); }
+ Address limit() { return allocation_info_.limit(); }
+
+ // The allocation top address.
+ Address* allocation_top_address() { return allocation_info_.top_address(); }
+
+ // The allocation limit address.
+ Address* allocation_limit_address() {
+ return allocation_info_.limit_address();
+ }
+
+ // Allocate the requested number of bytes in the space if possible, return a
+ // failure object if not.
+ MUST_USE_RESULT inline AllocationResult AllocateRaw(int size_in_bytes);
+
+ // Give a block of memory to the space's free list. It might be added to
+ // the free list or accounted as waste.
+ // If add_to_freelist is false then just accounting stats are updated and
+ // no attempt to add area to free list is made.
+ int Free(Address start, int size_in_bytes) {
+ int wasted = free_list_.Free(start, size_in_bytes);
+ accounting_stats_.DeallocateBytes(size_in_bytes);
+ accounting_stats_.WasteBytes(wasted);
+ return size_in_bytes - wasted;
+ }
+
+ void ResetFreeList() { free_list_.Reset(); }
+
+ // Set space allocation info.
+ void SetTopAndLimit(Address top, Address limit) {
+ DCHECK(top == limit ||
+ Page::FromAddress(top) == Page::FromAddress(limit - 1));
+ MemoryChunk::UpdateHighWaterMark(allocation_info_.top());
+ allocation_info_.set_top(top);
+ allocation_info_.set_limit(limit);
+ }
+
+ // Empty space allocation info, returning unused area to free list.
+ void EmptyAllocationInfo() {
+ // Mark the old linear allocation area with a free space map so it can be
+ // skipped when scanning the heap.
+ int old_linear_size = static_cast<int>(limit() - top());
+ Free(top(), old_linear_size);
+ SetTopAndLimit(NULL, NULL);
+ }
+
+ void Allocate(int bytes) { accounting_stats_.AllocateBytes(bytes); }
+
+ void IncreaseCapacity(int size);
+
+ // Releases an unused page and shrinks the space.
+ void ReleasePage(Page* page);
+
+ // The dummy page that anchors the linked list of pages.
+ Page* anchor() { return &anchor_; }
+
+#ifdef VERIFY_HEAP
+ // Verify integrity of this space.
+ virtual void Verify(ObjectVisitor* visitor);
+
+ // Overridden by subclasses to verify space-specific object
+ // properties (e.g., only maps or free-list nodes are in map space).
+ virtual void VerifyObject(HeapObject* obj) {}
+#endif
+
+#ifdef DEBUG
+ // Print meta info and objects in this space.
+ virtual void Print();
+
+ // Reports statistics for the space
+ void ReportStatistics();
+
+ // Report code object related statistics
+ void CollectCodeStatistics();
+ static void ReportCodeStatistics(Isolate* isolate);
+ static void ResetCodeStatistics(Isolate* isolate);
+#endif
+
+ // Evacuation candidates are swept by evacuator. Needs to return a valid
+ // result before _and_ after evacuation has finished.
+ static bool ShouldBeSweptBySweeperThreads(Page* p) {
+ return !p->IsEvacuationCandidate() &&
+ !p->IsFlagSet(Page::RESCAN_ON_EVACUATION) && !p->WasSwept();
+ }
+
+ void IncrementUnsweptFreeBytes(intptr_t by) { unswept_free_bytes_ += by; }
+
+ void IncreaseUnsweptFreeBytes(Page* p) {
+ DCHECK(ShouldBeSweptBySweeperThreads(p));
+ unswept_free_bytes_ += (p->area_size() - p->LiveBytes());
+ }
+
+ void DecrementUnsweptFreeBytes(intptr_t by) { unswept_free_bytes_ -= by; }
+
+ void DecreaseUnsweptFreeBytes(Page* p) {
+ DCHECK(ShouldBeSweptBySweeperThreads(p));
+ unswept_free_bytes_ -= (p->area_size() - p->LiveBytes());
+ }
+
+ void ResetUnsweptFreeBytes() { unswept_free_bytes_ = 0; }
+
+ // This function tries to steal size_in_bytes memory from the sweeper threads
+ // free-lists. If it does not succeed stealing enough memory, it will wait
+ // for the sweeper threads to finish sweeping.
+ // It returns true when sweeping is completed and false otherwise.
+ bool EnsureSweeperProgress(intptr_t size_in_bytes);
+
+ void set_end_of_unswept_pages(Page* page) { end_of_unswept_pages_ = page; }
+
+ Page* end_of_unswept_pages() { return end_of_unswept_pages_; }
+
+ Page* FirstPage() { return anchor_.next_page(); }
+ Page* LastPage() { return anchor_.prev_page(); }
+
+ void EvictEvacuationCandidatesFromFreeLists();
+
+ bool CanExpand();
+
+ // Returns the number of total pages in this space.
+ int CountTotalPages();
+
+ // Return size of allocatable area on a page in this space.
+ inline int AreaSize() { return area_size_; }
+
+ void CreateEmergencyMemory();
+ void FreeEmergencyMemory();
+ void UseEmergencyMemory();
+
+ bool HasEmergencyMemory() { return emergency_memory_ != NULL; }
+
+ protected:
+ FreeList* free_list() { return &free_list_; }
+
+ int area_size_;
+
+ // Maximum capacity of this space.
+ intptr_t max_capacity_;
+
+ intptr_t SizeOfFirstPage();
+
+ // Accounting information for this space.
+ AllocationStats accounting_stats_;
+
+ // The dummy page that anchors the double linked list of pages.
+ Page anchor_;
+
+ // The space's free list.
+ FreeList free_list_;
+
+ // Normal allocation information.
+ AllocationInfo allocation_info_;
+
+ // The number of free bytes which could be reclaimed by advancing the
+ // concurrent sweeper threads.
+ intptr_t unswept_free_bytes_;
+
+ // The sweeper threads iterate over the list of pointer and data space pages
+ // and sweep these pages concurrently. They will stop sweeping after the
+ // end_of_unswept_pages_ page.
+ Page* end_of_unswept_pages_;
+
+ // Emergency memory is the memory of a full page for a given space, allocated
+ // conservatively before evacuating a page. If compaction fails due to out
+ // of memory error the emergency memory can be used to complete compaction.
+ // If not used, the emergency memory is released after compaction.
+ MemoryChunk* emergency_memory_;
+
+ // Expands the space by allocating a fixed number of pages. Returns false if
+ // it cannot allocate requested number of pages from OS, or if the hard heap
+ // size limit has been hit.
+ bool Expand();
+
+ // Generic fast case allocation function that tries linear allocation at the
+ // address denoted by top in allocation_info_.
+ inline HeapObject* AllocateLinearly(int size_in_bytes);
+
+ // If sweeping is still in progress try to sweep unswept pages. If that is
+ // not successful, wait for the sweeper threads and re-try free-list
+ // allocation.
+ MUST_USE_RESULT HeapObject* WaitForSweeperThreadsAndRetryAllocation(
+ int size_in_bytes);
+
+ // Slow path of AllocateRaw. This function is space-dependent.
+ MUST_USE_RESULT HeapObject* SlowAllocateRaw(int size_in_bytes);
+
+ friend class PageIterator;
+ friend class MarkCompactCollector;
+};
+
+
+class NumberAndSizeInfo BASE_EMBEDDED {
+ public:
+ NumberAndSizeInfo() : number_(0), bytes_(0) {}
+
+ int number() const { return number_; }
+ void increment_number(int num) { number_ += num; }
+
+ int bytes() const { return bytes_; }
+ void increment_bytes(int size) { bytes_ += size; }
+
+ void clear() {
+ number_ = 0;
+ bytes_ = 0;
+ }
+
+ private:
+ int number_;
+ int bytes_;
+};
+
+
+// HistogramInfo class for recording a single "bar" of a histogram. This
+// class is used for collecting statistics to print to the log file.
+class HistogramInfo : public NumberAndSizeInfo {
+ public:
+ HistogramInfo() : NumberAndSizeInfo() {}
+
+ const char* name() { return name_; }
+ void set_name(const char* name) { name_ = name; }
+
+ private:
+ const char* name_;
+};
+
+
+enum SemiSpaceId { kFromSpace = 0, kToSpace = 1 };
+
+
+class SemiSpace;
+
+
+class NewSpacePage : public MemoryChunk {
+ public:
+ // GC related flags copied from from-space to to-space when
+ // flipping semispaces.
+ static const intptr_t kCopyOnFlipFlagsMask =
+ (1 << MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING) |
+ (1 << MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING) |
+ (1 << MemoryChunk::SCAN_ON_SCAVENGE);
+
+ static const int kAreaSize = Page::kMaxRegularHeapObjectSize;
+
+ inline NewSpacePage* next_page() const {
+ return static_cast<NewSpacePage*>(next_chunk());
+ }
+
+ inline void set_next_page(NewSpacePage* page) { set_next_chunk(page); }
+
+ inline NewSpacePage* prev_page() const {
+ return static_cast<NewSpacePage*>(prev_chunk());
+ }
+
+ inline void set_prev_page(NewSpacePage* page) { set_prev_chunk(page); }
+
+ SemiSpace* semi_space() { return reinterpret_cast<SemiSpace*>(owner()); }
+
+ bool is_anchor() { return !this->InNewSpace(); }
+
+ static bool IsAtStart(Address addr) {
+ return (reinterpret_cast<intptr_t>(addr) & Page::kPageAlignmentMask) ==
+ kObjectStartOffset;
+ }
+
+ static bool IsAtEnd(Address addr) {
+ return (reinterpret_cast<intptr_t>(addr) & Page::kPageAlignmentMask) == 0;
+ }
+
+ Address address() { return reinterpret_cast<Address>(this); }
+
+ // Finds the NewSpacePage containing the given address.
+ static inline NewSpacePage* FromAddress(Address address_in_page) {
+ Address page_start =
+ reinterpret_cast<Address>(reinterpret_cast<uintptr_t>(address_in_page) &
+ ~Page::kPageAlignmentMask);
+ NewSpacePage* page = reinterpret_cast<NewSpacePage*>(page_start);
+ return page;
+ }
+
+ // Find the page for a limit address. A limit address is either an address
+ // inside a page, or the address right after the last byte of a page.
+ static inline NewSpacePage* FromLimit(Address address_limit) {
+ return NewSpacePage::FromAddress(address_limit - 1);
+ }
+
+ // Checks if address1 and address2 are on the same new space page.
+ static inline bool OnSamePage(Address address1, Address address2) {
+ return NewSpacePage::FromAddress(address1) ==
+ NewSpacePage::FromAddress(address2);
+ }
+
+ private:
+ // Create a NewSpacePage object that is only used as anchor
+ // for the doubly-linked list of real pages.
+ explicit NewSpacePage(SemiSpace* owner) { InitializeAsAnchor(owner); }
+
+ static NewSpacePage* Initialize(Heap* heap, Address start,
+ SemiSpace* semi_space);
+
+ // Intialize a fake NewSpacePage used as sentinel at the ends
+ // of a doubly-linked list of real NewSpacePages.
+ // Only uses the prev/next links, and sets flags to not be in new-space.
+ void InitializeAsAnchor(SemiSpace* owner);
+
+ friend class SemiSpace;
+ friend class SemiSpaceIterator;
+};
+
+
+// -----------------------------------------------------------------------------
+// SemiSpace in young generation
+//
+// A semispace is a contiguous chunk of memory holding page-like memory
+// chunks. The mark-compact collector uses the memory of the first page in
+// the from space as a marking stack when tracing live objects.
+
+class SemiSpace : public Space {
+ public:
+ // Constructor.
+ SemiSpace(Heap* heap, SemiSpaceId semispace)
+ : Space(heap, NEW_SPACE, NOT_EXECUTABLE),
+ start_(NULL),
+ age_mark_(NULL),
+ id_(semispace),
+ anchor_(this),
+ current_page_(NULL) {}
+
+ // Sets up the semispace using the given chunk.
+ void SetUp(Address start, int initial_capacity, int maximum_capacity);
+
+ // Tear down the space. Heap memory was not allocated by the space, so it
+ // is not deallocated here.
+ void TearDown();
+
+ // True if the space has been set up but not torn down.
+ bool HasBeenSetUp() { return start_ != NULL; }
+
+ // Grow the semispace to the new capacity. The new capacity
+ // requested must be larger than the current capacity and less than
+ // the maximum capacity.
+ bool GrowTo(int new_capacity);
+
+ // Shrinks the semispace to the new capacity. The new capacity
+ // requested must be more than the amount of used memory in the
+ // semispace and less than the current capacity.
+ bool ShrinkTo(int new_capacity);
+
+ // Returns the start address of the first page of the space.
+ Address space_start() {
+ DCHECK(anchor_.next_page() != &anchor_);
+ return anchor_.next_page()->area_start();
+ }
+
+ // Returns the start address of the current page of the space.
+ Address page_low() { return current_page_->area_start(); }
+
+ // Returns one past the end address of the space.
+ Address space_end() { return anchor_.prev_page()->area_end(); }
+
+ // Returns one past the end address of the current page of the space.
+ Address page_high() { return current_page_->area_end(); }
+
+ bool AdvancePage() {
+ NewSpacePage* next_page = current_page_->next_page();
+ if (next_page == anchor()) return false;
+ current_page_ = next_page;
+ return true;
+ }
+
+ // Resets the space to using the first page.
+ void Reset();
+
+ // Age mark accessors.
+ Address age_mark() { return age_mark_; }
+ void set_age_mark(Address mark);
+
+ // True if the address is in the address range of this semispace (not
+ // necessarily below the allocation pointer).
+ bool Contains(Address a) {
+ return (reinterpret_cast<uintptr_t>(a) & address_mask_) ==
+ reinterpret_cast<uintptr_t>(start_);
+ }
+
+ // True if the object is a heap object in the address range of this
+ // semispace (not necessarily below the allocation pointer).
+ bool Contains(Object* o) {
+ return (reinterpret_cast<uintptr_t>(o) & object_mask_) == object_expected_;
+ }
+
+ // If we don't have these here then SemiSpace will be abstract. However
+ // they should never be called.
+ virtual intptr_t Size() {
+ UNREACHABLE();
+ return 0;
+ }
+
+ bool is_committed() { return committed_; }
+ bool Commit();
+ bool Uncommit();
+
+ NewSpacePage* first_page() { return anchor_.next_page(); }
+ NewSpacePage* current_page() { return current_page_; }
+
+#ifdef VERIFY_HEAP
+ virtual void Verify();
+#endif
+
+#ifdef DEBUG
+ virtual void Print();
+ // Validate a range of of addresses in a SemiSpace.
+ // The "from" address must be on a page prior to the "to" address,
+ // in the linked page order, or it must be earlier on the same page.
+ static void AssertValidRange(Address from, Address to);
+#else
+ // Do nothing.
+ inline static void AssertValidRange(Address from, Address to) {}
+#endif
+
+ // Returns the current total capacity of the semispace.
+ int TotalCapacity() { return total_capacity_; }
+
+ // Returns the maximum total capacity of the semispace.
+ int MaximumTotalCapacity() { return maximum_total_capacity_; }
+
+ // Returns the initial capacity of the semispace.
+ int InitialTotalCapacity() { return initial_total_capacity_; }
+
+ SemiSpaceId id() { return id_; }
+
+ static void Swap(SemiSpace* from, SemiSpace* to);
+
+ // Returns the maximum amount of memory ever committed by the semi space.
+ size_t MaximumCommittedMemory() { return maximum_committed_; }
+
+ // Approximate amount of physical memory committed for this space.
+ size_t CommittedPhysicalMemory();
+
+ private:
+ // Flips the semispace between being from-space and to-space.
+ // Copies the flags into the masked positions on all pages in the space.
+ void FlipPages(intptr_t flags, intptr_t flag_mask);
+
+ // Updates Capacity and MaximumCommitted based on new capacity.
+ void SetCapacity(int new_capacity);
+
+ NewSpacePage* anchor() { return &anchor_; }
+
+ // The current and maximum total capacity of the space.
+ int total_capacity_;
+ int maximum_total_capacity_;
+ int initial_total_capacity_;
+
+ intptr_t maximum_committed_;
+
+ // The start address of the space.
+ Address start_;
+ // Used to govern object promotion during mark-compact collection.
+ Address age_mark_;
+
+ // Masks and comparison values to test for containment in this semispace.
+ uintptr_t address_mask_;
+ uintptr_t object_mask_;
+ uintptr_t object_expected_;
+
+ bool committed_;
+ SemiSpaceId id_;
+
+ NewSpacePage anchor_;
+ NewSpacePage* current_page_;
+
+ friend class SemiSpaceIterator;
+ friend class NewSpacePageIterator;
+
+ public:
+ TRACK_MEMORY("SemiSpace")
+};
+
+
+// A SemiSpaceIterator is an ObjectIterator that iterates over the active
+// semispace of the heap's new space. It iterates over the objects in the
+// semispace from a given start address (defaulting to the bottom of the
+// semispace) to the top of the semispace. New objects allocated after the
+// iterator is created are not iterated.
+class SemiSpaceIterator : public ObjectIterator {
+ public:
+ // Create an iterator over the objects in the given space. If no start
+ // address is given, the iterator starts from the bottom of the space. If
+ // no size function is given, the iterator calls Object::Size().
+
+ // Iterate over all of allocated to-space.
+ explicit SemiSpaceIterator(NewSpace* space);
+ // Iterate over all of allocated to-space, with a custome size function.
+ SemiSpaceIterator(NewSpace* space, HeapObjectCallback size_func);
+ // Iterate over part of allocated to-space, from start to the end
+ // of allocation.
+ SemiSpaceIterator(NewSpace* space, Address start);
+ // Iterate from one address to another in the same semi-space.
+ SemiSpaceIterator(Address from, Address to);
+
+ HeapObject* Next() {
+ if (current_ == limit_) return NULL;
+ if (NewSpacePage::IsAtEnd(current_)) {
+ NewSpacePage* page = NewSpacePage::FromLimit(current_);
+ page = page->next_page();
+ DCHECK(!page->is_anchor());
+ current_ = page->area_start();
+ if (current_ == limit_) return NULL;
+ }
+
+ HeapObject* object = HeapObject::FromAddress(current_);
+ int size = (size_func_ == NULL) ? object->Size() : size_func_(object);
+
+ current_ += size;
+ return object;
+ }
+
+ // Implementation of the ObjectIterator functions.
+ virtual HeapObject* next_object() { return Next(); }
+
+ private:
+ void Initialize(Address start, Address end, HeapObjectCallback size_func);
+
+ // The current iteration point.
+ Address current_;
+ // The end of iteration.
+ Address limit_;
+ // The callback function.
+ HeapObjectCallback size_func_;
+};
+
+
+// -----------------------------------------------------------------------------
+// A PageIterator iterates the pages in a semi-space.
+class NewSpacePageIterator BASE_EMBEDDED {
+ public:
+ // Make an iterator that runs over all pages in to-space.
+ explicit inline NewSpacePageIterator(NewSpace* space);
+
+ // Make an iterator that runs over all pages in the given semispace,
+ // even those not used in allocation.
+ explicit inline NewSpacePageIterator(SemiSpace* space);
+
+ // Make iterator that iterates from the page containing start
+ // to the page that contains limit in the same semispace.
+ inline NewSpacePageIterator(Address start, Address limit);
+
+ inline bool has_next();
+ inline NewSpacePage* next();
+
+ private:
+ NewSpacePage* prev_page_; // Previous page returned.
+ // Next page that will be returned. Cached here so that we can use this
+ // iterator for operations that deallocate pages.
+ NewSpacePage* next_page_;
+ // Last page returned.
+ NewSpacePage* last_page_;
+};
+
+
+// -----------------------------------------------------------------------------
+// The young generation space.
+//
+// The new space consists of a contiguous pair of semispaces. It simply
+// forwards most functions to the appropriate semispace.
+
+class NewSpace : public Space {
+ public:
+ // Constructor.
+ explicit NewSpace(Heap* heap)
+ : Space(heap, NEW_SPACE, NOT_EXECUTABLE),
+ to_space_(heap, kToSpace),
+ from_space_(heap, kFromSpace),
+ reservation_(),
+ inline_allocation_limit_step_(0) {}
+
+ // Sets up the new space using the given chunk.
+ bool SetUp(int reserved_semispace_size_, int max_semi_space_size);
+
+ // Tears down the space. Heap memory was not allocated by the space, so it
+ // is not deallocated here.
+ void TearDown();
+
+ // True if the space has been set up but not torn down.
+ bool HasBeenSetUp() {
+ return to_space_.HasBeenSetUp() && from_space_.HasBeenSetUp();
+ }
+
+ // Flip the pair of spaces.
+ void Flip();
+
+ // Grow the capacity of the semispaces. Assumes that they are not at
+ // their maximum capacity.
+ void Grow();
+
+ // Shrink the capacity of the semispaces.
+ void Shrink();
+
+ // True if the address or object lies in the address range of either
+ // semispace (not necessarily below the allocation pointer).
+ bool Contains(Address a) {
+ return (reinterpret_cast<uintptr_t>(a) & address_mask_) ==
+ reinterpret_cast<uintptr_t>(start_);
+ }
+
+ bool Contains(Object* o) {
+ Address a = reinterpret_cast<Address>(o);
+ return (reinterpret_cast<uintptr_t>(a) & object_mask_) == object_expected_;
+ }
+
+ // Return the allocated bytes in the active semispace.
+ virtual intptr_t Size() {
+ return pages_used_ * NewSpacePage::kAreaSize +
+ static_cast<int>(top() - to_space_.page_low());
+ }
+
+ // The same, but returning an int. We have to have the one that returns
+ // intptr_t because it is inherited, but if we know we are dealing with the
+ // new space, which can't get as big as the other spaces then this is useful:
+ int SizeAsInt() { return static_cast<int>(Size()); }
+
+ // Return the allocatable capacity of a semispace.
+ intptr_t Capacity() {
+ SLOW_DCHECK(to_space_.TotalCapacity() == from_space_.TotalCapacity());
+ return (to_space_.TotalCapacity() / Page::kPageSize) *
+ NewSpacePage::kAreaSize;
+ }
+
+ // Return the current size of a semispace, allocatable and non-allocatable
+ // memory.
+ intptr_t TotalCapacity() {
+ DCHECK(to_space_.TotalCapacity() == from_space_.TotalCapacity());
+ return to_space_.TotalCapacity();
+ }
+
+ // Return the total amount of memory committed for new space.
+ intptr_t CommittedMemory() {
+ if (from_space_.is_committed()) return 2 * Capacity();
+ return TotalCapacity();
+ }
+
+ // Return the total amount of memory committed for new space.
+ intptr_t MaximumCommittedMemory() {
+ return to_space_.MaximumCommittedMemory() +
+ from_space_.MaximumCommittedMemory();
+ }
+
+ // Approximate amount of physical memory committed for this space.
+ size_t CommittedPhysicalMemory();
+
+ // Return the available bytes without growing.
+ intptr_t Available() { return Capacity() - Size(); }
+
+ // Return the maximum capacity of a semispace.
+ int MaximumCapacity() {
+ DCHECK(to_space_.MaximumTotalCapacity() ==
+ from_space_.MaximumTotalCapacity());
+ return to_space_.MaximumTotalCapacity();
+ }
+
+ bool IsAtMaximumCapacity() { return TotalCapacity() == MaximumCapacity(); }
+
+ // Returns the initial capacity of a semispace.
+ int InitialTotalCapacity() {
+ DCHECK(to_space_.InitialTotalCapacity() ==
+ from_space_.InitialTotalCapacity());
+ return to_space_.InitialTotalCapacity();
+ }
+
+ // Return the address of the allocation pointer in the active semispace.
+ Address top() {
+ DCHECK(to_space_.current_page()->ContainsLimit(allocation_info_.top()));
+ return allocation_info_.top();
+ }
+
+ void set_top(Address top) {
+ DCHECK(to_space_.current_page()->ContainsLimit(top));
+ allocation_info_.set_top(top);
+ }
+
+ // Return the address of the allocation pointer limit in the active semispace.
+ Address limit() {
+ DCHECK(to_space_.current_page()->ContainsLimit(allocation_info_.limit()));
+ return allocation_info_.limit();
+ }
+
+ // Return the address of the first object in the active semispace.
+ Address bottom() { return to_space_.space_start(); }
+
+ // Get the age mark of the inactive semispace.
+ Address age_mark() { return from_space_.age_mark(); }
+ // Set the age mark in the active semispace.
+ void set_age_mark(Address mark) { to_space_.set_age_mark(mark); }
+
+ // The start address of the space and a bit mask. Anding an address in the
+ // new space with the mask will result in the start address.
+ Address start() { return start_; }
+ uintptr_t mask() { return address_mask_; }
+
+ INLINE(uint32_t AddressToMarkbitIndex(Address addr)) {
+ DCHECK(Contains(addr));
+ DCHECK(IsAligned(OffsetFrom(addr), kPointerSize) ||
+ IsAligned(OffsetFrom(addr) - 1, kPointerSize));
+ return static_cast<uint32_t>(addr - start_) >> kPointerSizeLog2;
+ }
+
+ INLINE(Address MarkbitIndexToAddress(uint32_t index)) {
+ return reinterpret_cast<Address>(index << kPointerSizeLog2);
+ }
+
+ // The allocation top and limit address.
+ Address* allocation_top_address() { return allocation_info_.top_address(); }
+
+ // The allocation limit address.
+ Address* allocation_limit_address() {
+ return allocation_info_.limit_address();
+ }
+
+ MUST_USE_RESULT INLINE(AllocationResult AllocateRaw(int size_in_bytes));
+
+ // Reset the allocation pointer to the beginning of the active semispace.
+ void ResetAllocationInfo();
+
+ void UpdateInlineAllocationLimit(int size_in_bytes);
+ void LowerInlineAllocationLimit(intptr_t step) {
+ inline_allocation_limit_step_ = step;
+ UpdateInlineAllocationLimit(0);
+ top_on_previous_step_ = allocation_info_.top();
+ }
+
+ // Get the extent of the inactive semispace (for use as a marking stack,
+ // or to zap it). Notice: space-addresses are not necessarily on the
+ // same page, so FromSpaceStart() might be above FromSpaceEnd().
+ Address FromSpacePageLow() { return from_space_.page_low(); }
+ Address FromSpacePageHigh() { return from_space_.page_high(); }
+ Address FromSpaceStart() { return from_space_.space_start(); }
+ Address FromSpaceEnd() { return from_space_.space_end(); }
+
+ // Get the extent of the active semispace's pages' memory.
+ Address ToSpaceStart() { return to_space_.space_start(); }
+ Address ToSpaceEnd() { return to_space_.space_end(); }
+
+ inline bool ToSpaceContains(Address address) {
+ return to_space_.Contains(address);
+ }
+ inline bool FromSpaceContains(Address address) {
+ return from_space_.Contains(address);
+ }
+
+ // True if the object is a heap object in the address range of the
+ // respective semispace (not necessarily below the allocation pointer of the
+ // semispace).
+ inline bool ToSpaceContains(Object* o) { return to_space_.Contains(o); }
+ inline bool FromSpaceContains(Object* o) { return from_space_.Contains(o); }
+
+ // Try to switch the active semispace to a new, empty, page.
+ // Returns false if this isn't possible or reasonable (i.e., there
+ // are no pages, or the current page is already empty), or true
+ // if successful.
+ bool AddFreshPage();
+
+#ifdef VERIFY_HEAP
+ // Verify the active semispace.
+ virtual void Verify();
+#endif
+
+#ifdef DEBUG
+ // Print the active semispace.
+ virtual void Print() { to_space_.Print(); }
+#endif
+
+ // Iterates the active semispace to collect statistics.
+ void CollectStatistics();
+ // Reports previously collected statistics of the active semispace.
+ void ReportStatistics();
+ // Clears previously collected statistics.
+ void ClearHistograms();
+
+ // Record the allocation or promotion of a heap object. Note that we don't
+ // record every single allocation, but only those that happen in the
+ // to space during a scavenge GC.
+ void RecordAllocation(HeapObject* obj);
+ void RecordPromotion(HeapObject* obj);
+
+ // Return whether the operation succeded.
+ bool CommitFromSpaceIfNeeded() {
+ if (from_space_.is_committed()) return true;
+ return from_space_.Commit();
+ }
+
+ bool UncommitFromSpace() {
+ if (!from_space_.is_committed()) return true;
+ return from_space_.Uncommit();
+ }
+
+ inline intptr_t inline_allocation_limit_step() {
+ return inline_allocation_limit_step_;
+ }
+
+ SemiSpace* active_space() { return &to_space_; }
+
+ private:
+ // Update allocation info to match the current to-space page.
+ void UpdateAllocationInfo();
+
+ Address chunk_base_;
+ uintptr_t chunk_size_;
+
+ // The semispaces.
+ SemiSpace to_space_;
+ SemiSpace from_space_;
+ base::VirtualMemory reservation_;
+ int pages_used_;
+
+ // Start address and bit mask for containment testing.
+ Address start_;
+ uintptr_t address_mask_;
+ uintptr_t object_mask_;
+ uintptr_t object_expected_;
+
+ // Allocation pointer and limit for normal allocation and allocation during
+ // mark-compact collection.
+ AllocationInfo allocation_info_;
+
+ // When incremental marking is active we will set allocation_info_.limit
+ // to be lower than actual limit and then will gradually increase it
+ // in steps to guarantee that we do incremental marking steps even
+ // when all allocation is performed from inlined generated code.
+ intptr_t inline_allocation_limit_step_;
+
+ Address top_on_previous_step_;
+
+ HistogramInfo* allocated_histogram_;
+ HistogramInfo* promoted_histogram_;
+
+ MUST_USE_RESULT AllocationResult SlowAllocateRaw(int size_in_bytes);
+
+ friend class SemiSpaceIterator;
+
+ public:
+ TRACK_MEMORY("NewSpace")
+};
+
+
+// -----------------------------------------------------------------------------
+// Old object space (excluding map objects)
+
+class OldSpace : public PagedSpace {
+ public:
+ // Creates an old space object with a given maximum capacity.
+ // The constructor does not allocate pages from OS.
+ OldSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id,
+ Executability executable)
+ : PagedSpace(heap, max_capacity, id, executable) {}
+
+ public:
+ TRACK_MEMORY("OldSpace")
+};
+
+
+// For contiguous spaces, top should be in the space (or at the end) and limit
+// should be the end of the space.
+#define DCHECK_SEMISPACE_ALLOCATION_INFO(info, space) \
+ SLOW_DCHECK((space).page_low() <= (info).top() && \
+ (info).top() <= (space).page_high() && \
+ (info).limit() <= (space).page_high())
+
+
+// -----------------------------------------------------------------------------
+// Old space for all map objects
+
+class MapSpace : public PagedSpace {
+ public:
+ // Creates a map space object with a maximum capacity.
+ MapSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id)
+ : PagedSpace(heap, max_capacity, id, NOT_EXECUTABLE),
+ max_map_space_pages_(kMaxMapPageIndex - 1) {}
+
+ // Given an index, returns the page address.
+ // TODO(1600): this limit is artifical just to keep code compilable
+ static const int kMaxMapPageIndex = 1 << 16;
+
+ virtual int RoundSizeDownToObjectAlignment(int size) {
+ if (base::bits::IsPowerOfTwo32(Map::kSize)) {
+ return RoundDown(size, Map::kSize);
+ } else {
+ return (size / Map::kSize) * Map::kSize;
+ }
+ }
+
+ protected:
+ virtual void VerifyObject(HeapObject* obj);
+
+ private:
+ static const int kMapsPerPage = Page::kMaxRegularHeapObjectSize / Map::kSize;
+
+ // Do map space compaction if there is a page gap.
+ int CompactionThreshold() {
+ return kMapsPerPage * (max_map_space_pages_ - 1);
+ }
+
+ const int max_map_space_pages_;
+
+ public:
+ TRACK_MEMORY("MapSpace")
+};
+
+
+// -----------------------------------------------------------------------------
+// Old space for simple property cell objects
+
+class CellSpace : public PagedSpace {
+ public:
+ // Creates a property cell space object with a maximum capacity.
+ CellSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id)
+ : PagedSpace(heap, max_capacity, id, NOT_EXECUTABLE) {}
+
+ virtual int RoundSizeDownToObjectAlignment(int size) {
+ if (base::bits::IsPowerOfTwo32(Cell::kSize)) {
+ return RoundDown(size, Cell::kSize);
+ } else {
+ return (size / Cell::kSize) * Cell::kSize;
+ }
+ }
+
+ protected:
+ virtual void VerifyObject(HeapObject* obj);
+
+ public:
+ TRACK_MEMORY("CellSpace")
+};
+
+
+// -----------------------------------------------------------------------------
+// Old space for all global object property cell objects
+
+class PropertyCellSpace : public PagedSpace {
+ public:
+ // Creates a property cell space object with a maximum capacity.
+ PropertyCellSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id)
+ : PagedSpace(heap, max_capacity, id, NOT_EXECUTABLE) {}
+
+ virtual int RoundSizeDownToObjectAlignment(int size) {
+ if (base::bits::IsPowerOfTwo32(PropertyCell::kSize)) {
+ return RoundDown(size, PropertyCell::kSize);
+ } else {
+ return (size / PropertyCell::kSize) * PropertyCell::kSize;
+ }
+ }
+
+ protected:
+ virtual void VerifyObject(HeapObject* obj);
+
+ public:
+ TRACK_MEMORY("PropertyCellSpace")
+};
+
+
+// -----------------------------------------------------------------------------
+// Large objects ( > Page::kMaxHeapObjectSize ) are allocated and managed by
+// the large object space. A large object is allocated from OS heap with
+// extra padding bytes (Page::kPageSize + Page::kObjectStartOffset).
+// A large object always starts at Page::kObjectStartOffset to a page.
+// Large objects do not move during garbage collections.
+
+class LargeObjectSpace : public Space {
+ public:
+ LargeObjectSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id);
+ virtual ~LargeObjectSpace() {}
+
+ // Initializes internal data structures.
+ bool SetUp();
+
+ // Releases internal resources, frees objects in this space.
+ void TearDown();
+
+ static intptr_t ObjectSizeFor(intptr_t chunk_size) {
+ if (chunk_size <= (Page::kPageSize + Page::kObjectStartOffset)) return 0;
+ return chunk_size - Page::kPageSize - Page::kObjectStartOffset;
+ }
+
+ // Shared implementation of AllocateRaw, AllocateRawCode and
+ // AllocateRawFixedArray.
+ MUST_USE_RESULT AllocationResult
+ AllocateRaw(int object_size, Executability executable);
+
+ // Available bytes for objects in this space.
+ inline intptr_t Available();
+
+ virtual intptr_t Size() { return size_; }
+
+ virtual intptr_t SizeOfObjects() { return objects_size_; }
+
+ intptr_t MaximumCommittedMemory() { return maximum_committed_; }
+
+ intptr_t CommittedMemory() { return Size(); }
+
+ // Approximate amount of physical memory committed for this space.
+ size_t CommittedPhysicalMemory();
+
+ int PageCount() { return page_count_; }
+
+ // Finds an object for a given address, returns a Smi if it is not found.
+ // The function iterates through all objects in this space, may be slow.
+ Object* FindObject(Address a);
+
+ // Finds a large object page containing the given address, returns NULL
+ // if such a page doesn't exist.
+ LargePage* FindPage(Address a);
+
+ // Frees unmarked objects.
+ void FreeUnmarkedObjects();
+
+ // Checks whether a heap object is in this space; O(1).
+ bool Contains(HeapObject* obj);
+
+ // Checks whether the space is empty.
+ bool IsEmpty() { return first_page_ == NULL; }
+
+ LargePage* first_page() { return first_page_; }
+
+#ifdef VERIFY_HEAP
+ virtual void Verify();
+#endif
+
+#ifdef DEBUG
+ virtual void Print();
+ void ReportStatistics();
+ void CollectCodeStatistics();
+#endif
+ // Checks whether an address is in the object area in this space. It
+ // iterates all objects in the space. May be slow.
+ bool SlowContains(Address addr) { return FindObject(addr)->IsHeapObject(); }
+
+ private:
+ intptr_t max_capacity_;
+ intptr_t maximum_committed_;
+ // The head of the linked list of large object chunks.
+ LargePage* first_page_;
+ intptr_t size_; // allocated bytes
+ int page_count_; // number of chunks
+ intptr_t objects_size_; // size of objects
+ // Map MemoryChunk::kAlignment-aligned chunks to large pages covering them
+ HashMap chunk_map_;
+
+ friend class LargeObjectIterator;
+
+ public:
+ TRACK_MEMORY("LargeObjectSpace")
+};
+
+
+class LargeObjectIterator : public ObjectIterator {
+ public:
+ explicit LargeObjectIterator(LargeObjectSpace* space);
+ LargeObjectIterator(LargeObjectSpace* space, HeapObjectCallback size_func);
+
+ HeapObject* Next();
+
+ // implementation of ObjectIterator.
+ virtual HeapObject* next_object() { return Next(); }
+
+ private:
+ LargePage* current_;
+ HeapObjectCallback size_func_;
+};
+
+
+// Iterates over the chunks (pages and large object pages) that can contain
+// pointers to new space.
+class PointerChunkIterator BASE_EMBEDDED {
+ public:
+ inline explicit PointerChunkIterator(Heap* heap);
+
+ // Return NULL when the iterator is done.
+ MemoryChunk* next() {
+ switch (state_) {
+ case kOldPointerState: {
+ if (old_pointer_iterator_.has_next()) {
+ return old_pointer_iterator_.next();
+ }
+ state_ = kMapState;
+ // Fall through.
+ }
+ case kMapState: {
+ if (map_iterator_.has_next()) {
+ return map_iterator_.next();
+ }
+ state_ = kLargeObjectState;
+ // Fall through.
+ }
+ case kLargeObjectState: {
+ HeapObject* heap_object;
+ do {
+ heap_object = lo_iterator_.Next();
+ if (heap_object == NULL) {
+ state_ = kFinishedState;
+ return NULL;
+ }
+ // Fixed arrays are the only pointer-containing objects in large
+ // object space.
+ } while (!heap_object->IsFixedArray());
+ MemoryChunk* answer = MemoryChunk::FromAddress(heap_object->address());
+ return answer;
+ }
+ case kFinishedState:
+ return NULL;
+ default:
+ break;
+ }
+ UNREACHABLE();
+ return NULL;
+ }
+
+
+ private:
+ enum State { kOldPointerState, kMapState, kLargeObjectState, kFinishedState };
+ State state_;
+ PageIterator old_pointer_iterator_;
+ PageIterator map_iterator_;
+ LargeObjectIterator lo_iterator_;
+};
+
+
+#ifdef DEBUG
+struct CommentStatistic {
+ const char* comment;
+ int size;
+ int count;
+ void Clear() {
+ comment = NULL;
+ size = 0;
+ count = 0;
+ }
+ // Must be small, since an iteration is used for lookup.
+ static const int kMaxComments = 64;
+};
+#endif
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_SPACES_H_
diff --git a/src/heap/store-buffer-inl.h b/src/heap/store-buffer-inl.h
new file mode 100644
index 0000000..1606465
--- /dev/null
+++ b/src/heap/store-buffer-inl.h
@@ -0,0 +1,63 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_STORE_BUFFER_INL_H_
+#define V8_STORE_BUFFER_INL_H_
+
+#include "src/heap/store-buffer.h"
+
+namespace v8 {
+namespace internal {
+
+Address StoreBuffer::TopAddress() {
+ return reinterpret_cast<Address>(heap_->store_buffer_top_address());
+}
+
+
+void StoreBuffer::Mark(Address addr) {
+ DCHECK(!heap_->cell_space()->Contains(addr));
+ DCHECK(!heap_->code_space()->Contains(addr));
+ DCHECK(!heap_->old_data_space()->Contains(addr));
+ Address* top = reinterpret_cast<Address*>(heap_->store_buffer_top());
+ *top++ = addr;
+ heap_->public_set_store_buffer_top(top);
+ if ((reinterpret_cast<uintptr_t>(top) & kStoreBufferOverflowBit) != 0) {
+ DCHECK(top == limit_);
+ Compact();
+ } else {
+ DCHECK(top < limit_);
+ }
+}
+
+
+void StoreBuffer::EnterDirectlyIntoStoreBuffer(Address addr) {
+ if (store_buffer_rebuilding_enabled_) {
+ SLOW_DCHECK(!heap_->cell_space()->Contains(addr) &&
+ !heap_->code_space()->Contains(addr) &&
+ !heap_->old_data_space()->Contains(addr) &&
+ !heap_->new_space()->Contains(addr));
+ Address* top = old_top_;
+ *top++ = addr;
+ old_top_ = top;
+ old_buffer_is_sorted_ = false;
+ old_buffer_is_filtered_ = false;
+ if (top >= old_limit_) {
+ DCHECK(callback_ != NULL);
+ (*callback_)(heap_, MemoryChunk::FromAnyPointerAddress(heap_, addr),
+ kStoreBufferFullEvent);
+ }
+ }
+}
+
+
+void StoreBuffer::ClearDeadObject(HeapObject* object) {
+ Address& map_field = Memory::Address_at(object->address());
+ if (heap_->map_space()->Contains(map_field)) {
+ map_field = NULL;
+ }
+}
+}
+} // namespace v8::internal
+
+#endif // V8_STORE_BUFFER_INL_H_
diff --git a/src/heap/store-buffer.cc b/src/heap/store-buffer.cc
new file mode 100644
index 0000000..278e9f2
--- /dev/null
+++ b/src/heap/store-buffer.cc
@@ -0,0 +1,581 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <algorithm>
+
+#include "src/v8.h"
+
+#include "src/base/atomicops.h"
+#include "src/counters.h"
+#include "src/heap/store-buffer-inl.h"
+
+namespace v8 {
+namespace internal {
+
+StoreBuffer::StoreBuffer(Heap* heap)
+ : heap_(heap),
+ start_(NULL),
+ limit_(NULL),
+ old_start_(NULL),
+ old_limit_(NULL),
+ old_top_(NULL),
+ old_reserved_limit_(NULL),
+ old_buffer_is_sorted_(false),
+ old_buffer_is_filtered_(false),
+ during_gc_(false),
+ store_buffer_rebuilding_enabled_(false),
+ callback_(NULL),
+ may_move_store_buffer_entries_(true),
+ virtual_memory_(NULL),
+ hash_set_1_(NULL),
+ hash_set_2_(NULL),
+ hash_sets_are_empty_(true) {}
+
+
+void StoreBuffer::SetUp() {
+ virtual_memory_ = new base::VirtualMemory(kStoreBufferSize * 3);
+ uintptr_t start_as_int =
+ reinterpret_cast<uintptr_t>(virtual_memory_->address());
+ start_ =
+ reinterpret_cast<Address*>(RoundUp(start_as_int, kStoreBufferSize * 2));
+ limit_ = start_ + (kStoreBufferSize / kPointerSize);
+
+ old_virtual_memory_ =
+ new base::VirtualMemory(kOldStoreBufferLength * kPointerSize);
+ old_top_ = old_start_ =
+ reinterpret_cast<Address*>(old_virtual_memory_->address());
+ // Don't know the alignment requirements of the OS, but it is certainly not
+ // less than 0xfff.
+ DCHECK((reinterpret_cast<uintptr_t>(old_start_) & 0xfff) == 0);
+ int initial_length =
+ static_cast<int>(base::OS::CommitPageSize() / kPointerSize);
+ DCHECK(initial_length > 0);
+ DCHECK(initial_length <= kOldStoreBufferLength);
+ old_limit_ = old_start_ + initial_length;
+ old_reserved_limit_ = old_start_ + kOldStoreBufferLength;
+
+ CHECK(old_virtual_memory_->Commit(reinterpret_cast<void*>(old_start_),
+ (old_limit_ - old_start_) * kPointerSize,
+ false));
+
+ DCHECK(reinterpret_cast<Address>(start_) >= virtual_memory_->address());
+ DCHECK(reinterpret_cast<Address>(limit_) >= virtual_memory_->address());
+ Address* vm_limit = reinterpret_cast<Address*>(
+ reinterpret_cast<char*>(virtual_memory_->address()) +
+ virtual_memory_->size());
+ DCHECK(start_ <= vm_limit);
+ DCHECK(limit_ <= vm_limit);
+ USE(vm_limit);
+ DCHECK((reinterpret_cast<uintptr_t>(limit_) & kStoreBufferOverflowBit) != 0);
+ DCHECK((reinterpret_cast<uintptr_t>(limit_ - 1) & kStoreBufferOverflowBit) ==
+ 0);
+
+ CHECK(virtual_memory_->Commit(reinterpret_cast<Address>(start_),
+ kStoreBufferSize,
+ false)); // Not executable.
+ heap_->public_set_store_buffer_top(start_);
+
+ hash_set_1_ = new uintptr_t[kHashSetLength];
+ hash_set_2_ = new uintptr_t[kHashSetLength];
+ hash_sets_are_empty_ = false;
+
+ ClearFilteringHashSets();
+}
+
+
+void StoreBuffer::TearDown() {
+ delete virtual_memory_;
+ delete old_virtual_memory_;
+ delete[] hash_set_1_;
+ delete[] hash_set_2_;
+ old_start_ = old_top_ = old_limit_ = old_reserved_limit_ = NULL;
+ start_ = limit_ = NULL;
+ heap_->public_set_store_buffer_top(start_);
+}
+
+
+void StoreBuffer::StoreBufferOverflow(Isolate* isolate) {
+ isolate->heap()->store_buffer()->Compact();
+ isolate->counters()->store_buffer_overflows()->Increment();
+}
+
+
+void StoreBuffer::Uniq() {
+ // Remove adjacent duplicates and cells that do not point at new space.
+ Address previous = NULL;
+ Address* write = old_start_;
+ DCHECK(may_move_store_buffer_entries_);
+ for (Address* read = old_start_; read < old_top_; read++) {
+ Address current = *read;
+ if (current != previous) {
+ if (heap_->InNewSpace(*reinterpret_cast<Object**>(current))) {
+ *write++ = current;
+ }
+ }
+ previous = current;
+ }
+ old_top_ = write;
+}
+
+
+bool StoreBuffer::SpaceAvailable(intptr_t space_needed) {
+ return old_limit_ - old_top_ >= space_needed;
+}
+
+
+void StoreBuffer::EnsureSpace(intptr_t space_needed) {
+ while (old_limit_ - old_top_ < space_needed &&
+ old_limit_ < old_reserved_limit_) {
+ size_t grow = old_limit_ - old_start_; // Double size.
+ CHECK(old_virtual_memory_->Commit(reinterpret_cast<void*>(old_limit_),
+ grow * kPointerSize, false));
+ old_limit_ += grow;
+ }
+
+ if (SpaceAvailable(space_needed)) return;
+
+ if (old_buffer_is_filtered_) return;
+ DCHECK(may_move_store_buffer_entries_);
+ Compact();
+
+ old_buffer_is_filtered_ = true;
+ bool page_has_scan_on_scavenge_flag = false;
+
+ PointerChunkIterator it(heap_);
+ MemoryChunk* chunk;
+ while ((chunk = it.next()) != NULL) {
+ if (chunk->scan_on_scavenge()) {
+ page_has_scan_on_scavenge_flag = true;
+ break;
+ }
+ }
+
+ if (page_has_scan_on_scavenge_flag) {
+ Filter(MemoryChunk::SCAN_ON_SCAVENGE);
+ }
+
+ if (SpaceAvailable(space_needed)) return;
+
+ // Sample 1 entry in 97 and filter out the pages where we estimate that more
+ // than 1 in 8 pointers are to new space.
+ static const int kSampleFinenesses = 5;
+ static const struct Samples {
+ int prime_sample_step;
+ int threshold;
+ } samples[kSampleFinenesses] = {
+ {97, ((Page::kPageSize / kPointerSize) / 97) / 8},
+ {23, ((Page::kPageSize / kPointerSize) / 23) / 16},
+ {7, ((Page::kPageSize / kPointerSize) / 7) / 32},
+ {3, ((Page::kPageSize / kPointerSize) / 3) / 256},
+ {1, 0}};
+ for (int i = 0; i < kSampleFinenesses; i++) {
+ ExemptPopularPages(samples[i].prime_sample_step, samples[i].threshold);
+ // As a last resort we mark all pages as being exempt from the store buffer.
+ DCHECK(i != (kSampleFinenesses - 1) || old_top_ == old_start_);
+ if (SpaceAvailable(space_needed)) return;
+ }
+ UNREACHABLE();
+}
+
+
+// Sample the store buffer to see if some pages are taking up a lot of space
+// in the store buffer.
+void StoreBuffer::ExemptPopularPages(int prime_sample_step, int threshold) {
+ PointerChunkIterator it(heap_);
+ MemoryChunk* chunk;
+ while ((chunk = it.next()) != NULL) {
+ chunk->set_store_buffer_counter(0);
+ }
+ bool created_new_scan_on_scavenge_pages = false;
+ MemoryChunk* previous_chunk = NULL;
+ for (Address* p = old_start_; p < old_top_; p += prime_sample_step) {
+ Address addr = *p;
+ MemoryChunk* containing_chunk = NULL;
+ if (previous_chunk != NULL && previous_chunk->Contains(addr)) {
+ containing_chunk = previous_chunk;
+ } else {
+ containing_chunk = MemoryChunk::FromAnyPointerAddress(heap_, addr);
+ }
+ int old_counter = containing_chunk->store_buffer_counter();
+ if (old_counter >= threshold) {
+ containing_chunk->set_scan_on_scavenge(true);
+ created_new_scan_on_scavenge_pages = true;
+ }
+ containing_chunk->set_store_buffer_counter(old_counter + 1);
+ previous_chunk = containing_chunk;
+ }
+ if (created_new_scan_on_scavenge_pages) {
+ Filter(MemoryChunk::SCAN_ON_SCAVENGE);
+ }
+ old_buffer_is_filtered_ = true;
+}
+
+
+void StoreBuffer::Filter(int flag) {
+ Address* new_top = old_start_;
+ MemoryChunk* previous_chunk = NULL;
+ for (Address* p = old_start_; p < old_top_; p++) {
+ Address addr = *p;
+ MemoryChunk* containing_chunk = NULL;
+ if (previous_chunk != NULL && previous_chunk->Contains(addr)) {
+ containing_chunk = previous_chunk;
+ } else {
+ containing_chunk = MemoryChunk::FromAnyPointerAddress(heap_, addr);
+ previous_chunk = containing_chunk;
+ }
+ if (!containing_chunk->IsFlagSet(flag)) {
+ *new_top++ = addr;
+ }
+ }
+ old_top_ = new_top;
+
+ // Filtering hash sets are inconsistent with the store buffer after this
+ // operation.
+ ClearFilteringHashSets();
+}
+
+
+void StoreBuffer::SortUniq() {
+ Compact();
+ if (old_buffer_is_sorted_) return;
+ std::sort(old_start_, old_top_);
+ Uniq();
+
+ old_buffer_is_sorted_ = true;
+
+ // Filtering hash sets are inconsistent with the store buffer after this
+ // operation.
+ ClearFilteringHashSets();
+}
+
+
+bool StoreBuffer::PrepareForIteration() {
+ Compact();
+ PointerChunkIterator it(heap_);
+ MemoryChunk* chunk;
+ bool page_has_scan_on_scavenge_flag = false;
+ while ((chunk = it.next()) != NULL) {
+ if (chunk->scan_on_scavenge()) {
+ page_has_scan_on_scavenge_flag = true;
+ break;
+ }
+ }
+
+ if (page_has_scan_on_scavenge_flag) {
+ Filter(MemoryChunk::SCAN_ON_SCAVENGE);
+ }
+
+ // Filtering hash sets are inconsistent with the store buffer after
+ // iteration.
+ ClearFilteringHashSets();
+
+ return page_has_scan_on_scavenge_flag;
+}
+
+
+#ifdef DEBUG
+void StoreBuffer::Clean() {
+ ClearFilteringHashSets();
+ Uniq(); // Also removes things that no longer point to new space.
+ EnsureSpace(kStoreBufferSize / 2);
+}
+
+
+static Address* in_store_buffer_1_element_cache = NULL;
+
+
+bool StoreBuffer::CellIsInStoreBuffer(Address cell_address) {
+ if (!FLAG_enable_slow_asserts) return true;
+ if (in_store_buffer_1_element_cache != NULL &&
+ *in_store_buffer_1_element_cache == cell_address) {
+ return true;
+ }
+ Address* top = reinterpret_cast<Address*>(heap_->store_buffer_top());
+ for (Address* current = top - 1; current >= start_; current--) {
+ if (*current == cell_address) {
+ in_store_buffer_1_element_cache = current;
+ return true;
+ }
+ }
+ for (Address* current = old_top_ - 1; current >= old_start_; current--) {
+ if (*current == cell_address) {
+ in_store_buffer_1_element_cache = current;
+ return true;
+ }
+ }
+ return false;
+}
+#endif
+
+
+void StoreBuffer::ClearFilteringHashSets() {
+ if (!hash_sets_are_empty_) {
+ memset(reinterpret_cast<void*>(hash_set_1_), 0,
+ sizeof(uintptr_t) * kHashSetLength);
+ memset(reinterpret_cast<void*>(hash_set_2_), 0,
+ sizeof(uintptr_t) * kHashSetLength);
+ hash_sets_are_empty_ = true;
+ }
+}
+
+
+void StoreBuffer::GCPrologue() {
+ ClearFilteringHashSets();
+ during_gc_ = true;
+}
+
+
+#ifdef VERIFY_HEAP
+void StoreBuffer::VerifyPointers(LargeObjectSpace* space) {
+ LargeObjectIterator it(space);
+ for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) {
+ if (object->IsFixedArray()) {
+ Address slot_address = object->address();
+ Address end = object->address() + object->Size();
+
+ while (slot_address < end) {
+ HeapObject** slot = reinterpret_cast<HeapObject**>(slot_address);
+ // When we are not in GC the Heap::InNewSpace() predicate
+ // checks that pointers which satisfy predicate point into
+ // the active semispace.
+ Object* object = reinterpret_cast<Object*>(
+ base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
+ heap_->InNewSpace(object);
+ slot_address += kPointerSize;
+ }
+ }
+ }
+}
+#endif
+
+
+void StoreBuffer::Verify() {
+#ifdef VERIFY_HEAP
+ VerifyPointers(heap_->lo_space());
+#endif
+}
+
+
+void StoreBuffer::GCEpilogue() {
+ during_gc_ = false;
+#ifdef VERIFY_HEAP
+ if (FLAG_verify_heap) {
+ Verify();
+ }
+#endif
+}
+
+
+void StoreBuffer::FindPointersToNewSpaceInRegion(
+ Address start, Address end, ObjectSlotCallback slot_callback,
+ bool clear_maps) {
+ for (Address slot_address = start; slot_address < end;
+ slot_address += kPointerSize) {
+ Object** slot = reinterpret_cast<Object**>(slot_address);
+ Object* object = reinterpret_cast<Object*>(
+ base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
+ if (heap_->InNewSpace(object)) {
+ HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
+ DCHECK(heap_object->IsHeapObject());
+ // The new space object was not promoted if it still contains a map
+ // pointer. Clear the map field now lazily.
+ if (clear_maps) ClearDeadObject(heap_object);
+ slot_callback(reinterpret_cast<HeapObject**>(slot), heap_object);
+ object = reinterpret_cast<Object*>(
+ base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
+ if (heap_->InNewSpace(object)) {
+ EnterDirectlyIntoStoreBuffer(slot_address);
+ }
+ }
+ }
+}
+
+
+void StoreBuffer::IteratePointersInStoreBuffer(ObjectSlotCallback slot_callback,
+ bool clear_maps) {
+ Address* limit = old_top_;
+ old_top_ = old_start_;
+ {
+ DontMoveStoreBufferEntriesScope scope(this);
+ for (Address* current = old_start_; current < limit; current++) {
+#ifdef DEBUG
+ Address* saved_top = old_top_;
+#endif
+ Object** slot = reinterpret_cast<Object**>(*current);
+ Object* object = reinterpret_cast<Object*>(
+ base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
+ if (heap_->InFromSpace(object)) {
+ HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
+ // The new space object was not promoted if it still contains a map
+ // pointer. Clear the map field now lazily.
+ if (clear_maps) ClearDeadObject(heap_object);
+ slot_callback(reinterpret_cast<HeapObject**>(slot), heap_object);
+ object = reinterpret_cast<Object*>(
+ base::NoBarrier_Load(reinterpret_cast<base::AtomicWord*>(slot)));
+ if (heap_->InNewSpace(object)) {
+ EnterDirectlyIntoStoreBuffer(reinterpret_cast<Address>(slot));
+ }
+ }
+ DCHECK(old_top_ == saved_top + 1 || old_top_ == saved_top);
+ }
+ }
+}
+
+
+void StoreBuffer::IteratePointersToNewSpace(ObjectSlotCallback slot_callback) {
+ IteratePointersToNewSpace(slot_callback, false);
+}
+
+
+void StoreBuffer::IteratePointersToNewSpaceAndClearMaps(
+ ObjectSlotCallback slot_callback) {
+ IteratePointersToNewSpace(slot_callback, true);
+}
+
+
+void StoreBuffer::IteratePointersToNewSpace(ObjectSlotCallback slot_callback,
+ bool clear_maps) {
+ // We do not sort or remove duplicated entries from the store buffer because
+ // we expect that callback will rebuild the store buffer thus removing
+ // all duplicates and pointers to old space.
+ bool some_pages_to_scan = PrepareForIteration();
+
+ // TODO(gc): we want to skip slots on evacuation candidates
+ // but we can't simply figure that out from slot address
+ // because slot can belong to a large object.
+ IteratePointersInStoreBuffer(slot_callback, clear_maps);
+
+ // We are done scanning all the pointers that were in the store buffer, but
+ // there may be some pages marked scan_on_scavenge that have pointers to new
+ // space that are not in the store buffer. We must scan them now. As we
+ // scan, the surviving pointers to new space will be added to the store
+ // buffer. If there are still a lot of pointers to new space then we will
+ // keep the scan_on_scavenge flag on the page and discard the pointers that
+ // were added to the store buffer. If there are not many pointers to new
+ // space left on the page we will keep the pointers in the store buffer and
+ // remove the flag from the page.
+ if (some_pages_to_scan) {
+ if (callback_ != NULL) {
+ (*callback_)(heap_, NULL, kStoreBufferStartScanningPagesEvent);
+ }
+ PointerChunkIterator it(heap_);
+ MemoryChunk* chunk;
+ while ((chunk = it.next()) != NULL) {
+ if (chunk->scan_on_scavenge()) {
+ chunk->set_scan_on_scavenge(false);
+ if (callback_ != NULL) {
+ (*callback_)(heap_, chunk, kStoreBufferScanningPageEvent);
+ }
+ if (chunk->owner() == heap_->lo_space()) {
+ LargePage* large_page = reinterpret_cast<LargePage*>(chunk);
+ HeapObject* array = large_page->GetObject();
+ DCHECK(array->IsFixedArray());
+ Address start = array->address();
+ Address end = start + array->Size();
+ FindPointersToNewSpaceInRegion(start, end, slot_callback, clear_maps);
+ } else {
+ Page* page = reinterpret_cast<Page*>(chunk);
+ PagedSpace* owner = reinterpret_cast<PagedSpace*>(page->owner());
+ if (owner == heap_->map_space()) {
+ DCHECK(page->WasSwept());
+ HeapObjectIterator iterator(page, NULL);
+ for (HeapObject* heap_object = iterator.Next(); heap_object != NULL;
+ heap_object = iterator.Next()) {
+ // We skip free space objects.
+ if (!heap_object->IsFiller()) {
+ DCHECK(heap_object->IsMap());
+ FindPointersToNewSpaceInRegion(
+ heap_object->address() + Map::kPointerFieldsBeginOffset,
+ heap_object->address() + Map::kPointerFieldsEndOffset,
+ slot_callback, clear_maps);
+ }
+ }
+ } else {
+ if (!page->SweepingCompleted()) {
+ heap_->mark_compact_collector()->SweepInParallel(page, owner);
+ if (!page->SweepingCompleted()) {
+ // We were not able to sweep that page, i.e., a concurrent
+ // sweeper thread currently owns this page.
+ // TODO(hpayer): This may introduce a huge pause here. We
+ // just care about finish sweeping of the scan on scavenge page.
+ heap_->mark_compact_collector()->EnsureSweepingCompleted();
+ }
+ }
+ CHECK(page->owner() == heap_->old_pointer_space());
+ HeapObjectIterator iterator(page, NULL);
+ for (HeapObject* heap_object = iterator.Next(); heap_object != NULL;
+ heap_object = iterator.Next()) {
+ // We iterate over objects that contain new space pointers only.
+ if (!heap_object->MayContainRawValues()) {
+ FindPointersToNewSpaceInRegion(
+ heap_object->address() + HeapObject::kHeaderSize,
+ heap_object->address() + heap_object->Size(), slot_callback,
+ clear_maps);
+ }
+ }
+ }
+ }
+ }
+ }
+ if (callback_ != NULL) {
+ (*callback_)(heap_, NULL, kStoreBufferScanningPageEvent);
+ }
+ }
+}
+
+
+void StoreBuffer::Compact() {
+ Address* top = reinterpret_cast<Address*>(heap_->store_buffer_top());
+
+ if (top == start_) return;
+
+ // There's no check of the limit in the loop below so we check here for
+ // the worst case (compaction doesn't eliminate any pointers).
+ DCHECK(top <= limit_);
+ heap_->public_set_store_buffer_top(start_);
+ EnsureSpace(top - start_);
+ DCHECK(may_move_store_buffer_entries_);
+ // Goes through the addresses in the store buffer attempting to remove
+ // duplicates. In the interest of speed this is a lossy operation. Some
+ // duplicates will remain. We have two hash sets with different hash
+ // functions to reduce the number of unnecessary clashes.
+ hash_sets_are_empty_ = false; // Hash sets are in use.
+ for (Address* current = start_; current < top; current++) {
+ DCHECK(!heap_->cell_space()->Contains(*current));
+ DCHECK(!heap_->code_space()->Contains(*current));
+ DCHECK(!heap_->old_data_space()->Contains(*current));
+ uintptr_t int_addr = reinterpret_cast<uintptr_t>(*current);
+ // Shift out the last bits including any tags.
+ int_addr >>= kPointerSizeLog2;
+ // The upper part of an address is basically random because of ASLR and OS
+ // non-determinism, so we use only the bits within a page for hashing to
+ // make v8's behavior (more) deterministic.
+ uintptr_t hash_addr =
+ int_addr & (Page::kPageAlignmentMask >> kPointerSizeLog2);
+ int hash1 = ((hash_addr ^ (hash_addr >> kHashSetLengthLog2)) &
+ (kHashSetLength - 1));
+ if (hash_set_1_[hash1] == int_addr) continue;
+ uintptr_t hash2 = (hash_addr - (hash_addr >> kHashSetLengthLog2));
+ hash2 ^= hash2 >> (kHashSetLengthLog2 * 2);
+ hash2 &= (kHashSetLength - 1);
+ if (hash_set_2_[hash2] == int_addr) continue;
+ if (hash_set_1_[hash1] == 0) {
+ hash_set_1_[hash1] = int_addr;
+ } else if (hash_set_2_[hash2] == 0) {
+ hash_set_2_[hash2] = int_addr;
+ } else {
+ // Rather than slowing down we just throw away some entries. This will
+ // cause some duplicates to remain undetected.
+ hash_set_1_[hash1] = int_addr;
+ hash_set_2_[hash2] = 0;
+ }
+ old_buffer_is_sorted_ = false;
+ old_buffer_is_filtered_ = false;
+ *old_top_++ = reinterpret_cast<Address>(int_addr << kPointerSizeLog2);
+ DCHECK(old_top_ <= old_limit_);
+ }
+ heap_->isolate()->counters()->store_buffer_compactions()->Increment();
+}
+}
+} // namespace v8::internal
diff --git a/src/heap/store-buffer.h b/src/heap/store-buffer.h
new file mode 100644
index 0000000..5efd692
--- /dev/null
+++ b/src/heap/store-buffer.h
@@ -0,0 +1,221 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_STORE_BUFFER_H_
+#define V8_STORE_BUFFER_H_
+
+#include "src/allocation.h"
+#include "src/base/logging.h"
+#include "src/base/platform/platform.h"
+#include "src/globals.h"
+
+namespace v8 {
+namespace internal {
+
+class Page;
+class PagedSpace;
+class StoreBuffer;
+
+typedef void (*ObjectSlotCallback)(HeapObject** from, HeapObject* to);
+
+typedef void (StoreBuffer::*RegionCallback)(Address start, Address end,
+ ObjectSlotCallback slot_callback,
+ bool clear_maps);
+
+// Used to implement the write barrier by collecting addresses of pointers
+// between spaces.
+class StoreBuffer {
+ public:
+ explicit StoreBuffer(Heap* heap);
+
+ static void StoreBufferOverflow(Isolate* isolate);
+
+ inline Address TopAddress();
+
+ void SetUp();
+ void TearDown();
+
+ // This is used by the mutator to enter addresses into the store buffer.
+ inline void Mark(Address addr);
+
+ // This is used by the heap traversal to enter the addresses into the store
+ // buffer that should still be in the store buffer after GC. It enters
+ // addresses directly into the old buffer because the GC starts by wiping the
+ // old buffer and thereafter only visits each cell once so there is no need
+ // to attempt to remove any dupes. During the first part of a GC we
+ // are using the store buffer to access the old spaces and at the same time
+ // we are rebuilding the store buffer using this function. There is, however
+ // no issue of overwriting the buffer we are iterating over, because this
+ // stage of the scavenge can only reduce the number of addresses in the store
+ // buffer (some objects are promoted so pointers to them do not need to be in
+ // the store buffer). The later parts of the GC scan the pages that are
+ // exempt from the store buffer and process the promotion queue. These steps
+ // can overflow this buffer. We check for this and on overflow we call the
+ // callback set up with the StoreBufferRebuildScope object.
+ inline void EnterDirectlyIntoStoreBuffer(Address addr);
+
+ // Iterates over all pointers that go from old space to new space. It will
+ // delete the store buffer as it starts so the callback should reenter
+ // surviving old-to-new pointers into the store buffer to rebuild it.
+ void IteratePointersToNewSpace(ObjectSlotCallback callback);
+
+ // Same as IteratePointersToNewSpace but additonally clears maps in objects
+ // referenced from the store buffer that do not contain a forwarding pointer.
+ void IteratePointersToNewSpaceAndClearMaps(ObjectSlotCallback callback);
+
+ static const int kStoreBufferOverflowBit = 1 << (14 + kPointerSizeLog2);
+ static const int kStoreBufferSize = kStoreBufferOverflowBit;
+ static const int kStoreBufferLength = kStoreBufferSize / sizeof(Address);
+ static const int kOldStoreBufferLength = kStoreBufferLength * 16;
+ static const int kHashSetLengthLog2 = 12;
+ static const int kHashSetLength = 1 << kHashSetLengthLog2;
+
+ void Compact();
+
+ void GCPrologue();
+ void GCEpilogue();
+
+ Object*** Limit() { return reinterpret_cast<Object***>(old_limit_); }
+ Object*** Start() { return reinterpret_cast<Object***>(old_start_); }
+ Object*** Top() { return reinterpret_cast<Object***>(old_top_); }
+ void SetTop(Object*** top) {
+ DCHECK(top >= Start());
+ DCHECK(top <= Limit());
+ old_top_ = reinterpret_cast<Address*>(top);
+ }
+
+ bool old_buffer_is_sorted() { return old_buffer_is_sorted_; }
+ bool old_buffer_is_filtered() { return old_buffer_is_filtered_; }
+
+ // Goes through the store buffer removing pointers to things that have
+ // been promoted. Rebuilds the store buffer completely if it overflowed.
+ void SortUniq();
+
+ void EnsureSpace(intptr_t space_needed);
+ void Verify();
+
+ bool PrepareForIteration();
+
+#ifdef DEBUG
+ void Clean();
+ // Slow, for asserts only.
+ bool CellIsInStoreBuffer(Address cell);
+#endif
+
+ void Filter(int flag);
+
+ private:
+ Heap* heap_;
+
+ // The store buffer is divided up into a new buffer that is constantly being
+ // filled by mutator activity and an old buffer that is filled with the data
+ // from the new buffer after compression.
+ Address* start_;
+ Address* limit_;
+
+ Address* old_start_;
+ Address* old_limit_;
+ Address* old_top_;
+ Address* old_reserved_limit_;
+ base::VirtualMemory* old_virtual_memory_;
+
+ bool old_buffer_is_sorted_;
+ bool old_buffer_is_filtered_;
+ bool during_gc_;
+ // The garbage collector iterates over many pointers to new space that are not
+ // handled by the store buffer. This flag indicates whether the pointers
+ // found by the callbacks should be added to the store buffer or not.
+ bool store_buffer_rebuilding_enabled_;
+ StoreBufferCallback callback_;
+ bool may_move_store_buffer_entries_;
+
+ base::VirtualMemory* virtual_memory_;
+
+ // Two hash sets used for filtering.
+ // If address is in the hash set then it is guaranteed to be in the
+ // old part of the store buffer.
+ uintptr_t* hash_set_1_;
+ uintptr_t* hash_set_2_;
+ bool hash_sets_are_empty_;
+
+ void ClearFilteringHashSets();
+
+ bool SpaceAvailable(intptr_t space_needed);
+ void Uniq();
+ void ExemptPopularPages(int prime_sample_step, int threshold);
+
+ // Set the map field of the object to NULL if contains a map.
+ inline void ClearDeadObject(HeapObject* object);
+
+ void IteratePointersToNewSpace(ObjectSlotCallback callback, bool clear_maps);
+
+ void FindPointersToNewSpaceInRegion(Address start, Address end,
+ ObjectSlotCallback slot_callback,
+ bool clear_maps);
+
+ // For each region of pointers on a page in use from an old space call
+ // visit_pointer_region callback.
+ // If either visit_pointer_region or callback can cause an allocation
+ // in old space and changes in allocation watermark then
+ // can_preallocate_during_iteration should be set to true.
+ void IteratePointersOnPage(PagedSpace* space, Page* page,
+ RegionCallback region_callback,
+ ObjectSlotCallback slot_callback);
+
+ void IteratePointersInStoreBuffer(ObjectSlotCallback slot_callback,
+ bool clear_maps);
+
+#ifdef VERIFY_HEAP
+ void VerifyPointers(LargeObjectSpace* space);
+#endif
+
+ friend class StoreBufferRebuildScope;
+ friend class DontMoveStoreBufferEntriesScope;
+};
+
+
+class StoreBufferRebuildScope {
+ public:
+ explicit StoreBufferRebuildScope(Heap* heap, StoreBuffer* store_buffer,
+ StoreBufferCallback callback)
+ : store_buffer_(store_buffer),
+ stored_state_(store_buffer->store_buffer_rebuilding_enabled_),
+ stored_callback_(store_buffer->callback_) {
+ store_buffer_->store_buffer_rebuilding_enabled_ = true;
+ store_buffer_->callback_ = callback;
+ (*callback)(heap, NULL, kStoreBufferStartScanningPagesEvent);
+ }
+
+ ~StoreBufferRebuildScope() {
+ store_buffer_->callback_ = stored_callback_;
+ store_buffer_->store_buffer_rebuilding_enabled_ = stored_state_;
+ }
+
+ private:
+ StoreBuffer* store_buffer_;
+ bool stored_state_;
+ StoreBufferCallback stored_callback_;
+};
+
+
+class DontMoveStoreBufferEntriesScope {
+ public:
+ explicit DontMoveStoreBufferEntriesScope(StoreBuffer* store_buffer)
+ : store_buffer_(store_buffer),
+ stored_state_(store_buffer->may_move_store_buffer_entries_) {
+ store_buffer_->may_move_store_buffer_entries_ = false;
+ }
+
+ ~DontMoveStoreBufferEntriesScope() {
+ store_buffer_->may_move_store_buffer_entries_ = stored_state_;
+ }
+
+ private:
+ StoreBuffer* store_buffer_;
+ bool stored_state_;
+};
+}
+} // namespace v8::internal
+
+#endif // V8_STORE_BUFFER_H_
diff --git a/src/heap/sweeper-thread.cc b/src/heap/sweeper-thread.cc
new file mode 100644
index 0000000..b0e8cea
--- /dev/null
+++ b/src/heap/sweeper-thread.cc
@@ -0,0 +1,82 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/heap/sweeper-thread.h"
+
+#include "src/v8.h"
+
+#include "src/isolate.h"
+#include "src/v8threads.h"
+
+namespace v8 {
+namespace internal {
+
+static const int kSweeperThreadStackSize = 64 * KB;
+
+SweeperThread::SweeperThread(Isolate* isolate)
+ : Thread(Thread::Options("v8:SweeperThread", kSweeperThreadStackSize)),
+ isolate_(isolate),
+ heap_(isolate->heap()),
+ collector_(heap_->mark_compact_collector()),
+ start_sweeping_semaphore_(0),
+ end_sweeping_semaphore_(0),
+ stop_semaphore_(0) {
+ DCHECK(!FLAG_job_based_sweeping);
+ base::NoBarrier_Store(&stop_thread_, static_cast<base::AtomicWord>(false));
+}
+
+
+void SweeperThread::Run() {
+ Isolate::SetIsolateThreadLocals(isolate_, NULL);
+ DisallowHeapAllocation no_allocation;
+ DisallowHandleAllocation no_handles;
+ DisallowHandleDereference no_deref;
+
+ while (true) {
+ start_sweeping_semaphore_.Wait();
+
+ if (base::Acquire_Load(&stop_thread_)) {
+ stop_semaphore_.Signal();
+ return;
+ }
+
+ collector_->SweepInParallel(heap_->old_data_space(), 0);
+ collector_->SweepInParallel(heap_->old_pointer_space(), 0);
+ end_sweeping_semaphore_.Signal();
+ }
+}
+
+
+void SweeperThread::Stop() {
+ base::Release_Store(&stop_thread_, static_cast<base::AtomicWord>(true));
+ start_sweeping_semaphore_.Signal();
+ stop_semaphore_.Wait();
+ Join();
+}
+
+
+void SweeperThread::StartSweeping() { start_sweeping_semaphore_.Signal(); }
+
+
+void SweeperThread::WaitForSweeperThread() { end_sweeping_semaphore_.Wait(); }
+
+
+bool SweeperThread::SweepingCompleted() {
+ bool value = end_sweeping_semaphore_.WaitFor(base::TimeDelta::FromSeconds(0));
+ if (value) {
+ end_sweeping_semaphore_.Signal();
+ }
+ return value;
+}
+
+
+int SweeperThread::NumberOfThreads(int max_available) {
+ if (!FLAG_concurrent_sweeping && !FLAG_parallel_sweeping) return 0;
+ if (FLAG_sweeper_threads > 0) return FLAG_sweeper_threads;
+ if (FLAG_concurrent_sweeping) return max_available - 1;
+ DCHECK(FLAG_parallel_sweeping);
+ return max_available;
+}
+}
+} // namespace v8::internal
diff --git a/src/heap/sweeper-thread.h b/src/heap/sweeper-thread.h
new file mode 100644
index 0000000..fc6bdda
--- /dev/null
+++ b/src/heap/sweeper-thread.h
@@ -0,0 +1,45 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_HEAP_SWEEPER_THREAD_H_
+#define V8_HEAP_SWEEPER_THREAD_H_
+
+#include "src/base/atomicops.h"
+#include "src/base/platform/platform.h"
+#include "src/flags.h"
+#include "src/utils.h"
+
+#include "src/heap/spaces.h"
+
+#include "src/heap/heap.h"
+
+namespace v8 {
+namespace internal {
+
+class SweeperThread : public base::Thread {
+ public:
+ explicit SweeperThread(Isolate* isolate);
+ ~SweeperThread() {}
+
+ void Run();
+ void Stop();
+ void StartSweeping();
+ void WaitForSweeperThread();
+ bool SweepingCompleted();
+
+ static int NumberOfThreads(int max_available);
+
+ private:
+ Isolate* isolate_;
+ Heap* heap_;
+ MarkCompactCollector* collector_;
+ base::Semaphore start_sweeping_semaphore_;
+ base::Semaphore end_sweeping_semaphore_;
+ base::Semaphore stop_semaphore_;
+ volatile base::AtomicWord stop_thread_;
+};
+}
+} // namespace v8::internal
+
+#endif // V8_HEAP_SWEEPER_THREAD_H_