deps: update v8 to 3.28.73

Reviewed-By: Fedor Indutny <fedor@indutny.com>
PR-URL: https://github.com/joyent/node/pull/8476

1 files changed, 0 insertions, 730 deletions

diff --git a/deps/v8/src/store-buffer.cc b/deps/v8/src/store-buffer.cc
deleted file mode 100644
index b0f7d2f803..0000000000
--- a/deps/v8/src/store-buffer.cc
+++ /dev/null
@@ -1,730 +0,0 @@
-// 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 "store-buffer.h"
-
-#include <algorithm>
-
-#include "v8.h"
-#include "counters.h"
-#include "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 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 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.
-  ASSERT((reinterpret_cast<uintptr_t>(old_start_) & 0xfff) == 0);
-  int initial_length = static_cast<int>(OS::CommitPageSize() / kPointerSize);
-  ASSERT(initial_length > 0);
-  ASSERT(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));
-
-  ASSERT(reinterpret_cast<Address>(start_) >= virtual_memory_->address());
-  ASSERT(reinterpret_cast<Address>(limit_) >= virtual_memory_->address());
-  Address* vm_limit = reinterpret_cast<Address*>(
-      reinterpret_cast<char*>(virtual_memory_->address()) +
-          virtual_memory_->size());
-  ASSERT(start_ <= vm_limit);
-  ASSERT(limit_ <= vm_limit);
-  USE(vm_limit);
-  ASSERT((reinterpret_cast<uintptr_t>(limit_) & kStoreBufferOverflowBit) != 0);
-  ASSERT((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_;
-  ASSERT(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;
-  ASSERT(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.
-    ASSERT(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
-static void DummyScavengePointer(HeapObject** p, HeapObject* o) {
-  // Do nothing.
-}
-
-
-void StoreBuffer::VerifyPointers(PagedSpace* space,
-                                 RegionCallback region_callback) {
-  PageIterator it(space);
-
-  while (it.has_next()) {
-    Page* page = it.next();
-    FindPointersToNewSpaceOnPage(
-        reinterpret_cast<PagedSpace*>(page->owner()),
-        page,
-        region_callback,
-        &DummyScavengePointer,
-        false);
-  }
-}
-
-
-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*>(
-            NoBarrier_Load(reinterpret_cast<AtomicWord*>(slot)));
-        heap_->InNewSpace(object);
-        slot_address += kPointerSize;
-      }
-    }
-  }
-}
-#endif
-
-
-void StoreBuffer::Verify() {
-#ifdef VERIFY_HEAP
-  VerifyPointers(heap_->old_pointer_space(),
-                 &StoreBuffer::FindPointersToNewSpaceInRegion);
-  VerifyPointers(heap_->map_space(),
-                 &StoreBuffer::FindPointersToNewSpaceInMapsRegion);
-  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*>(
-        NoBarrier_Load(reinterpret_cast<AtomicWord*>(slot)));
-    if (heap_->InNewSpace(object)) {
-      HeapObject* heap_object = reinterpret_cast<HeapObject*>(object);
-      ASSERT(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*>(
-          NoBarrier_Load(reinterpret_cast<AtomicWord*>(slot)));
-      if (heap_->InNewSpace(object)) {
-        EnterDirectlyIntoStoreBuffer(slot_address);
-      }
-    }
-  }
-}
-
-
-// Compute start address of the first map following given addr.
-static inline Address MapStartAlign(Address addr) {
-  Address page = Page::FromAddress(addr)->area_start();
-  return page + (((addr - page) + (Map::kSize - 1)) / Map::kSize * Map::kSize);
-}
-
-
-// Compute end address of the first map preceding given addr.
-static inline Address MapEndAlign(Address addr) {
-  Address page = Page::FromAllocationTop(addr)->area_start();
-  return page + ((addr - page) / Map::kSize * Map::kSize);
-}
-
-
-void StoreBuffer::FindPointersToNewSpaceInMaps(
-    Address start,
-    Address end,
-    ObjectSlotCallback slot_callback,
-    bool clear_maps) {
-  ASSERT(MapStartAlign(start) == start);
-  ASSERT(MapEndAlign(end) == end);
-
-  Address map_address = start;
-  while (map_address < end) {
-    ASSERT(!heap_->InNewSpace(Memory::Object_at(map_address)));
-    ASSERT(Memory::Object_at(map_address)->IsMap());
-
-    Address pointer_fields_start = map_address + Map::kPointerFieldsBeginOffset;
-    Address pointer_fields_end = map_address + Map::kPointerFieldsEndOffset;
-
-    FindPointersToNewSpaceInRegion(pointer_fields_start,
-                                   pointer_fields_end,
-                                   slot_callback,
-                                   clear_maps);
-    map_address += Map::kSize;
-  }
-}
-
-
-void StoreBuffer::FindPointersToNewSpaceInMapsRegion(
-    Address start,
-    Address end,
-    ObjectSlotCallback slot_callback,
-    bool clear_maps) {
-  Address map_aligned_start = MapStartAlign(start);
-  Address map_aligned_end   = MapEndAlign(end);
-
-  ASSERT(map_aligned_start == start);
-  ASSERT(map_aligned_end == end);
-
-  FindPointersToNewSpaceInMaps(map_aligned_start,
-                               map_aligned_end,
-                               slot_callback,
-                               clear_maps);
-}
-
-
-// This function iterates over all the pointers in a paged space in the heap,
-// looking for pointers into new space.  Within the pages there may be dead
-// objects that have not been overwritten by free spaces or fillers because of
-// concurrent sweeping.  These dead objects may not contain pointers to new
-// space. The garbage areas that have been swept properly (these will normally
-// be the large ones) will be marked with free space and filler map words.  In
-// addition any area that has never been used at all for object allocation must
-// be marked with a free space or filler.  Because the free space and filler
-// maps do not move we can always recognize these even after a compaction.
-// Normal objects like FixedArrays and JSObjects should not contain references
-// to these maps.  Constant pool array objects may contain references to these
-// maps, however, constant pool arrays cannot contain pointers to new space
-// objects, therefore they are skipped.  The special garbage section (see
-// comment in spaces.h) is skipped since it can contain absolutely anything.
-// Any objects that are allocated during iteration may or may not be visited by
-// the iteration, but they will not be partially visited.
-void StoreBuffer::FindPointersToNewSpaceOnPage(
-    PagedSpace* space,
-    Page* page,
-    RegionCallback region_callback,
-    ObjectSlotCallback slot_callback,
-    bool clear_maps) {
-  Address visitable_start = page->area_start();
-  Address end_of_page = page->area_end();
-
-  Address visitable_end = visitable_start;
-
-  Object* free_space_map = heap_->free_space_map();
-  Object* two_pointer_filler_map = heap_->two_pointer_filler_map();
-  Object* constant_pool_array_map = heap_->constant_pool_array_map();
-
-  while (visitable_end < end_of_page) {
-    // The sweeper thread concurrently may write free space maps and size to
-    // this page. We need acquire load here to make sure that we get a
-    // consistent view of maps and their sizes.
-    Object* o = reinterpret_cast<Object*>(
-        Acquire_Load(reinterpret_cast<AtomicWord*>(visitable_end)));
-    // Skip fillers or constant pool arrays (which never contain new-space
-    // pointers but can contain pointers which can be confused for fillers)
-    // but not things that look like fillers in the special garbage section
-    // which can contain anything.
-    if (o == free_space_map ||
-        o == two_pointer_filler_map ||
-        o == constant_pool_array_map ||
-        (visitable_end == space->top() && visitable_end != space->limit())) {
-      if (visitable_start != visitable_end) {
-        // After calling this the special garbage section may have moved.
-        (this->*region_callback)(visitable_start,
-                                 visitable_end,
-                                 slot_callback,
-                                 clear_maps);
-        if (visitable_end >= space->top() && visitable_end < space->limit()) {
-          visitable_end = space->limit();
-          visitable_start = visitable_end;
-          continue;
-        }
-      }
-      if (visitable_end == space->top() && visitable_end != space->limit()) {
-        visitable_start = visitable_end = space->limit();
-      } else {
-        // At this point we are either at the start of a filler, a
-        // constant pool array, or we are at the point where the space->top()
-        // used to be before the visit_pointer_region call above.  Either way we
-        // can skip the object at the current spot:  We don't promise to visit
-        // objects allocated during heap traversal, and if space->top() moved
-        // then it must be because an object was allocated at this point.
-        visitable_start =
-            visitable_end + HeapObject::FromAddress(visitable_end)->Size();
-        visitable_end = visitable_start;
-      }
-    } else {
-      ASSERT(o != free_space_map);
-      ASSERT(o != two_pointer_filler_map);
-      ASSERT(o != constant_pool_array_map);
-      ASSERT(visitable_end < space->top() || visitable_end >= space->limit());
-      visitable_end += kPointerSize;
-    }
-  }
-  ASSERT(visitable_end == end_of_page);
-  if (visitable_start != visitable_end) {
-    (this->*region_callback)(visitable_start,
-                             visitable_end,
-                             slot_callback,
-                             clear_maps);
-  }
-}
-
-
-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*>(
-          NoBarrier_Load(reinterpret_cast<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*>(
-            NoBarrier_Load(reinterpret_cast<AtomicWord*>(slot)));
-        if (heap_->InNewSpace(object)) {
-          EnterDirectlyIntoStoreBuffer(reinterpret_cast<Address>(slot));
-        }
-      }
-      ASSERT(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();
-          ASSERT(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());
-          FindPointersToNewSpaceOnPage(
-              owner,
-              page,
-              (owner == heap_->map_space() ?
-                 &StoreBuffer::FindPointersToNewSpaceInMapsRegion :
-                 &StoreBuffer::FindPointersToNewSpaceInRegion),
-              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).
-  ASSERT(top <= limit_);
-  heap_->public_set_store_buffer_top(start_);
-  EnsureSpace(top - start_);
-  ASSERT(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++) {
-    ASSERT(!heap_->cell_space()->Contains(*current));
-    ASSERT(!heap_->code_space()->Contains(*current));
-    ASSERT(!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);
-    ASSERT(old_top_ <= old_limit_);
-  }
-  heap_->isolate()->counters()->store_buffer_compactions()->Increment();
-}
-
-} }  // namespace v8::internal