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/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