Merge V8 at 3.9.24.13
Bug: 5688872
Change-Id: Id0aa8d23375030494d3189c31774059c0f5398fc
diff --git a/src/store-buffer.h b/src/store-buffer.h
new file mode 100644
index 0000000..951a9ca
--- /dev/null
+++ b/src/store-buffer.h
@@ -0,0 +1,255 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_STORE_BUFFER_H_
+#define V8_STORE_BUFFER_H_
+
+#include "allocation.h"
+#include "checks.h"
+#include "globals.h"
+#include "platform.h"
+#include "v8globals.h"
+
+namespace v8 {
+namespace internal {
+
+class StoreBuffer;
+
+typedef void (*ObjectSlotCallback)(HeapObject** from, HeapObject* to);
+
+typedef void (StoreBuffer::*RegionCallback)(
+ Address start, Address end, ObjectSlotCallback slot_callback);
+
+// 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);
+
+ 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) {
+ ASSERT(top >= Start());
+ ASSERT(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_;
+ 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_;
+
+ 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();
+
+ void CheckForFullBuffer();
+ void Uniq();
+ void ExemptPopularPages(int prime_sample_step, int threshold);
+
+ void FindPointersToNewSpaceInRegion(Address start,
+ Address end,
+ ObjectSlotCallback slot_callback);
+
+ // 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 FindPointersToNewSpaceInMaps(
+ Address start,
+ Address end,
+ ObjectSlotCallback slot_callback);
+
+ void FindPointersToNewSpaceInMapsRegion(
+ Address start,
+ Address end,
+ ObjectSlotCallback slot_callback);
+
+ void FindPointersToNewSpaceOnPage(
+ PagedSpace* space,
+ Page* page,
+ RegionCallback region_callback,
+ ObjectSlotCallback slot_callback);
+
+ void IteratePointersInStoreBuffer(ObjectSlotCallback slot_callback);
+
+#ifdef DEBUG
+ void VerifyPointers(PagedSpace* space, RegionCallback region_callback);
+ void VerifyPointers(LargeObjectSpace* space);
+#endif
+
+ friend class StoreBufferRebuildScope;
+ friend class DontMoveStoreBufferEntriesScope;
+};
+
+
+class StoreBufferRebuildScope {
+ public:
+ explicit StoreBufferRebuildScope(Heap* heap,
+ StoreBuffer* store_buffer,
+ StoreBufferCallback callback)
+ : heap_(heap),
+ 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_;
+ store_buffer_->CheckForFullBuffer();
+ }
+
+ private:
+ Heap* heap_;
+ 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_