Move a bunch of GC related files to heap/ subdirectory

src/incremental-marking.cc

Index: src/incremental-marking.cc
diff --git a/src/incremental-marking.cc b/src/incremental-marking.cc
deleted file mode 100644
index 431e1ce456f4ae0cef4ee50d7a32149885a3dfe4..0000000000000000000000000000000000000000
--- a/src/incremental-marking.cc
+++ /dev/null
@@ -1,987 +0,0 @@
-// 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/incremental-marking.h"
-
-#include "src/code-stubs.h"
-#include "src/compilation-cache.h"
-#include "src/conversions.h"
-#include "src/objects-visiting.h"
-#include "src/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::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() && WorthActivating() && heap_->NextGCIsLikelyToBeFull()) {
-    // 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::Step(intptr_t allocated_bytes,
-                              CompletionAction action) {
-  if (heap_->gc_state() != Heap::NOT_IN_GC ||
-      !FLAG_incremental_marking ||
-      !FLAG_incremental_marking_steps ||
-      (state_ != SWEEPING && state_ != MARKING)) {
-    return;
-  }
-
-  allocated_ += allocated_bytes;
-
-  if (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_++;
-
-    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_);
-        }
-      }
-    }
-
-    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