[heap] Reland "Remove black pages and use black areas instead."

BUG=chromium:630969,chromium:630386

Review-Url: https://codereview.chromium.org/2186863005
Cr-Commit-Position: refs/heads/master@{#38195}

src/heap/heap-inl.h

@@ -252,11 +252,6 @@ AllocationResult Heap::AllocateRaw(int size_in_bytes, AllocationSpace space,
     old_gen_exhausted_ = true;
   }
 
-  if (!old_gen_exhausted_ && incremental_marking()->black_allocation() &&
-      space != OLD_SPACE) {
-    Marking::MarkBlack(ObjectMarking::MarkBitFrom(object));
-    MemoryChunk::IncrementLiveBytesFromGC(object, size_in_bytes);
-  }
   return allocation;
 }
 

src/heap/heap.cc

@@ -3066,6 +3066,16 @@ void Heap::CreateFillerObjectAt(Address addr, int size,
   if (mode == ClearRecordedSlots::kYes) {
     ClearRecordedSlotRange(addr, addr + size);
   }
+
+  // If the location where the filler is created is within a black area we have
+  // to clear the mark bits of the filler space.
+  if (incremental_marking()->black_allocation() &&
+      Marking::IsBlackOrGrey(ObjectMarking::MarkBitFrom(addr))) {
+    Page* page = Page::FromAddress(addr);
+    page->markbits()->ClearRange(page->AddressToMarkbitIndex(addr),
+                                 page->AddressToMarkbitIndex(addr + size));
+  }
+
   // At this point, we may be deserializing the heap from a snapshot, and
   // none of the maps have been created yet and are NULL.
   DCHECK((filler->map() == NULL && !deserialization_complete_) ||
@@ -3130,13 +3140,20 @@ FixedArrayBase* Heap::LeftTrimFixedArray(FixedArrayBase* object,
   DCHECK(elements_to_trim <= len);
 
   // Calculate location of new array start.
-  Address new_start = object->address() + bytes_to_trim;
+  Address old_start = object->address();
+  Address new_start = old_start + bytes_to_trim;
+
+  // Transfer the mark bits to their new location if the object is not within
+  // a black area.
+  if (!incremental_marking()->black_allocation() ||
+      !Marking::IsBlack(ObjectMarking::MarkBitFrom(new_start))) {
+    IncrementalMarking::TransferMark(this, old_start, new_start);
+  }
 
   // Technically in new space this write might be omitted (except for
   // debug mode which iterates through the heap), but to play safer
   // we still do it.
-  CreateFillerObjectAt(object->address(), bytes_to_trim,
-                       ClearRecordedSlots::kYes);
+  CreateFillerObjectAt(old_start, bytes_to_trim, ClearRecordedSlots::kYes);
   // Initialize header of the trimmed array. Since left trimming is only
   // performed on pages which are not concurrently swept creating a filler
   // object does not require synchronization.
@@ -3145,18 +3162,18 @@ FixedArrayBase* Heap::LeftTrimFixedArray(FixedArrayBase* object,
   int new_start_index = elements_to_trim * (element_size / kPointerSize);
   former_start[new_start_index] = map;
   former_start[new_start_index + 1] = Smi::FromInt(len - elements_to_trim);
+
   FixedArrayBase* new_object =
       FixedArrayBase::cast(HeapObject::FromAddress(new_start));
 
+  // Maintain consistency of live bytes during incremental marking
+  AdjustLiveBytes(new_object, -bytes_to_trim, Heap::CONCURRENT_TO_SWEEPER);
+
   // Remove recorded slots for the new map and length offset.
   ClearRecordedSlot(new_object, HeapObject::RawField(new_object, 0));
   ClearRecordedSlot(new_object, HeapObject::RawField(
                                     new_object, FixedArrayBase::kLengthOffset));
 
-  // Maintain consistency of live bytes during incremental marking
-  IncrementalMarking::TransferMark(this, object->address(), new_start);
-  AdjustLiveBytes(new_object, -bytes_to_trim, Heap::CONCURRENT_TO_SWEEPER);
-
   // Notify the heap profiler of change in object layout.
   OnMoveEvent(new_object, object, new_object->Size());
   return new_object;
@@ -4174,14 +4191,13 @@ void Heap::RegisterReservationsForBlackAllocation(Reservation* reservations) {
   // Hence we have to color all objects of the reservation first black to avoid
   // unnecessary marking deque load.
   if (incremental_marking()->black_allocation()) {
-    for (int i = CODE_SPACE; i < Serializer::kNumberOfSpaces; i++) {
+    for (int i = OLD_SPACE; i < Serializer::kNumberOfSpaces; i++) {
       const Heap::Reservation& res = reservations[i];
       for (auto& chunk : res) {
         Address addr = chunk.start;
         while (addr < chunk.end) {
           HeapObject* obj = HeapObject::FromAddress(addr);
           Marking::MarkBlack(ObjectMarking::MarkBitFrom(obj));
-          MemoryChunk::IncrementLiveBytesFromGC(obj, obj->Size());
           addr += obj->Size();
         }
       }

src/heap/incremental-marking.cc

@@ -164,9 +164,7 @@ void IncrementalMarking::TransferMark(Heap* heap, Address old_start,
   DCHECK(MemoryChunk::FromAddress(old_start) ==
          MemoryChunk::FromAddress(new_start));
 
-  if (!heap->incremental_marking()->IsMarking() ||
-      Page::FromAddress(old_start)->IsFlagSet(Page::BLACK_PAGE))
-    return;
+  if (!heap->incremental_marking()->IsMarking()) return;
 
   // If the mark doesn't move, we don't check the color of the object.
   // It doesn't matter whether the object is black, since it hasn't changed
@@ -603,9 +601,9 @@ void IncrementalMarking::StartBlackAllocation() {
   DCHECK(FLAG_black_allocation);
   DCHECK(IsMarking());
   black_allocation_ = true;
-  OldSpace* old_space = heap()->old_space();
-  old_space->EmptyAllocationInfo();
-  old_space->free_list()->Reset();
+  heap()->old_space()->MarkAllocationInfoBlack();
+  heap()->map_space()->MarkAllocationInfoBlack();
+  heap()->code_space()->MarkAllocationInfoBlack();
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Black allocation started\n");
   }
@@ -833,7 +831,7 @@ void IncrementalMarking::UpdateMarkingDequeAfterScavenge() {
       // them.
       if (map_word.IsForwardingAddress()) {
         HeapObject* dest = map_word.ToForwardingAddress();
-        if (Page::FromAddress(dest->address())->IsFlagSet(Page::BLACK_PAGE))
+        if (Marking::IsBlack(ObjectMarking::MarkBitFrom(dest->address())))
           continue;
         array[new_top] = dest;
         new_top = ((new_top + 1) & mask);

src/heap/incremental-marking.h

@@ -208,12 +208,17 @@ class IncrementalMarking {
 
   static void TransferMark(Heap* heap, Address old_start, Address new_start);
 
-  // Returns true if the transferred color is black.
-  INLINE(static bool TransferColor(HeapObject* from, HeapObject* to)) {
-    if (Page::FromAddress(to->address())->IsFlagSet(Page::BLACK_PAGE))
-      return true;
+  // Returns true if the color transfer requires live bytes updating.
+  INLINE(static bool TransferColor(HeapObject* from, HeapObject* to,
+                                   int size)) {
     MarkBit from_mark_bit = ObjectMarking::MarkBitFrom(from);
     MarkBit to_mark_bit = ObjectMarking::MarkBitFrom(to);
+
+    if (Marking::IsBlack(to_mark_bit)) {
+      DCHECK(to->GetHeap()->incremental_marking()->black_allocation());
+      return false;
+    }
+
     DCHECK(Marking::IsWhite(to_mark_bit));
     if (from_mark_bit.Get()) {
       to_mark_bit.Set();

src/heap/mark-compact-inl.h

@@ -153,20 +153,46 @@ HeapObject* LiveObjectIterator<T>::Next() {
         cell_base_ = it_.CurrentCellBase();
         current_cell_ = *it_.CurrentCell();
       }
-      if (T == kBlackObjects && (current_cell_ & second_bit_index)) {
-        object = HeapObject::FromAddress(addr);
-      } else if (T == kGreyObjects && !(current_cell_ & second_bit_index)) {
-        object = HeapObject::FromAddress(addr);
-      } else if (T == kAllLiveObjects) {
+
+      if (current_cell_ & second_bit_index) {
+        // We found a black object. If the black object is within a black area,
+        // make sure that we skip all set bits in the black area until the
+        // object ends.
+        HeapObject* black_object = HeapObject::FromAddress(addr);
+        Address end = addr + black_object->Size() - kPointerSize;
+        DCHECK_EQ(chunk_, MemoryChunk::FromAddress(end));
+        uint32_t end_mark_bit_index = chunk_->AddressToMarkbitIndex(end);
+        unsigned int end_cell_index =
+            end_mark_bit_index >> Bitmap::kBitsPerCellLog2;
+        MarkBit::CellType end_index_mask =
+            1u << Bitmap::IndexInCell(end_mark_bit_index);
+        if (it_.Advance(end_cell_index)) {
+          cell_base_ = it_.CurrentCellBase();
+          current_cell_ = *it_.CurrentCell();
+        }
+
+        // Clear all bits in current_cell, including the end index.
+        current_cell_ &= ~(end_index_mask + end_index_mask - 1);
+
+        if (T == kBlackObjects || T == kAllLiveObjects) {
+          object = black_object;
+        }
+      } else if ((T == kGreyObjects || T == kAllLiveObjects)) {
         object = HeapObject::FromAddress(addr);
       }
 
-      // Clear the second bit of the found object.
-      current_cell_ &= ~second_bit_index;
-
       // We found a live object.
-      if (object != nullptr) break;
+      if (object != nullptr) {
+        if (object->IsFiller()) {
+          // Black areas together with slack tracking may result in black filler
+          // objects. We filter these objects out in the iterator.
+          object = nullptr;
+        } else {
+          break;
+        }
+      }
     }
+
     if (current_cell_ == 0) {
       if (!it_.Done()) {
         it_.Advance();

src/heap/mark-compact.cc

@@ -104,30 +104,30 @@ static void VerifyMarking(Heap* heap, Address bottom, Address top) {
   VerifyMarkingVisitor visitor(heap);
   HeapObject* object;
   Address next_object_must_be_here_or_later = bottom;
-
-  for (Address current = bottom; current < top; current += kPointerSize) {
+  for (Address current = bottom; current < top;) {
     object = HeapObject::FromAddress(current);
     if (MarkCompactCollector::IsMarked(object)) {
       CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(object)));
       CHECK(current >= next_object_must_be_here_or_later);
       object->Iterate(&visitor);
       next_object_must_be_here_or_later = current + object->Size();
-      // The next word for sure belongs to the current object, jump over it.
+      // The object is either part of a black area of black allocation or a
+      // regular black object
+      Page* page = Page::FromAddress(current);
+      CHECK(
+          page->markbits()->AllBitsSetInRange(
+              page->AddressToMarkbitIndex(current),
+              page->AddressToMarkbitIndex(next_object_must_be_here_or_later)) ||
+          page->markbits()->AllBitsClearInRange(
+              page->AddressToMarkbitIndex(current + kPointerSize * 2),
+              page->AddressToMarkbitIndex(next_object_must_be_here_or_later)));
+      current = next_object_must_be_here_or_later;
+    } else {
       current += kPointerSize;
     }
   }
 }
 
-static void VerifyMarkingBlackPage(Heap* heap, Page* page) {
-  CHECK(page->IsFlagSet(Page::BLACK_PAGE));
-  VerifyMarkingVisitor visitor(heap);
-  HeapObjectIterator it(page);
-  for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) {
-    CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(object)));
-    object->Iterate(&visitor);
-  }
-}
-
 static void VerifyMarking(NewSpace* space) {
   Address end = space->top();
   // The bottom position is at the start of its page. Allows us to use
@@ -146,11 +146,7 @@ static void VerifyMarking(NewSpace* space) {
 
 static void VerifyMarking(PagedSpace* space) {
   for (Page* p : *space) {
-    if (p->IsFlagSet(Page::BLACK_PAGE)) {
-      VerifyMarkingBlackPage(space->heap(), p);
-    } else {
-      VerifyMarking(space->heap(), p->area_start(), p->area_end());
-    }
+    VerifyMarking(space->heap(), p->area_start(), p->area_end());
   }
 }
 
@@ -409,9 +405,6 @@ void MarkCompactCollector::VerifyOmittedMapChecks() {
 static void ClearMarkbitsInPagedSpace(PagedSpace* space) {
   for (Page* p : *space) {
     p->ClearLiveness();
-    if (p->IsFlagSet(Page::BLACK_PAGE)) {
-      p->ClearFlag(Page::BLACK_PAGE);
-    }
   }
 }
 
@@ -435,9 +428,6 @@ void MarkCompactCollector::ClearMarkbits() {
     MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
     chunk->ResetProgressBar();
     chunk->ResetLiveBytes();
-    if (chunk->IsFlagSet(Page::BLACK_PAGE)) {
-      chunk->ClearFlag(Page::BLACK_PAGE);
-    }
   }
 }
 
@@ -659,7 +649,6 @@ void MarkCompactCollector::CollectEvacuationCandidates(PagedSpace* space) {
 
   for (Page* p : *space) {
     if (p->NeverEvacuate()) continue;
-    if (p->IsFlagSet(Page::BLACK_PAGE)) continue;
     // Invariant: Evacuation candidates are just created when marking is
     // started. This means that sweeping has finished. Furthermore, at the end
     // of a GC all evacuation candidates are cleared and their slot buffers are
@@ -1913,9 +1902,7 @@ class MarkCompactCollector::EvacuateRecordOnlyVisitor final
 
 void MarkCompactCollector::DiscoverGreyObjectsInSpace(PagedSpace* space) {
   for (Page* p : *space) {
-    if (!p->IsFlagSet(Page::BLACK_PAGE)) {
-      DiscoverGreyObjectsOnPage(p);
-    }
+    DiscoverGreyObjectsOnPage(p);
     if (marking_deque()->IsFull()) return;
   }
 }
@@ -2932,9 +2919,8 @@ bool MarkCompactCollector::IsSlotInBlackObject(MemoryChunk* p, Address slot) {
   DCHECK(owner != heap_->lo_space() && owner != nullptr);
   USE(owner);
 
-  // If we are on a black page, we cannot find the actual object start
-  // easiliy. We just return true but do not set the out_object.
-  if (p->IsFlagSet(Page::BLACK_PAGE)) {
+  // We may be part of a black area.
+  if (Marking::IsBlackOrGrey(ObjectMarking::MarkBitFrom(slot))) {
     return true;
   }
 
@@ -3031,27 +3017,16 @@ HeapObject* MarkCompactCollector::FindBlackObjectBySlotSlow(Address slot) {
     return nullptr;
   }
 
-  if (p->IsFlagSet(Page::BLACK_PAGE)) {
-    HeapObjectIterator it(p);
-    HeapObject* object = nullptr;
-    while ((object = it.Next()) != nullptr) {
-      int size = object->Size();
-      if (object->address() > slot) return nullptr;
-      if (object->address() <= slot && slot < (object->address() + size)) {
-        return object;
-      }
-    }
-  } else {
-    LiveObjectIterator<kBlackObjects> it(p);
-    HeapObject* object = nullptr;
-    while ((object = it.Next()) != nullptr) {
-      int size = object->Size();
-      if (object->address() > slot) return nullptr;
-      if (object->address() <= slot && slot < (object->address() + size)) {
-        return object;
-      }
+  LiveObjectIterator<kBlackObjects> it(p);
+  HeapObject* object = nullptr;
+  while ((object = it.Next()) != nullptr) {
+    int size = object->Size();
+    if (object->address() > slot) return nullptr;
+    if (object->address() <= slot && slot < (object->address() + size)) {
+      return object;
     }
   }
+
   return nullptr;
 }
 
@@ -3388,7 +3363,6 @@ int MarkCompactCollector::Sweeper::RawSweep(
   DCHECK(free_list_mode == IGNORE_FREE_LIST || space->identity() == OLD_SPACE ||
          space->identity() == CODE_SPACE || space->identity() == MAP_SPACE);
   DCHECK(!p->IsEvacuationCandidate() && !p->SweepingDone());
-  DCHECK(!p->IsFlagSet(Page::BLACK_PAGE));
 
   // Before we sweep objects on the page, we free dead array buffers which
   // requires valid mark bits.
@@ -3941,7 +3915,6 @@ void MarkCompactCollector::Sweeper::AddSweepingPageSafe(AllocationSpace space,
 }
 
 void MarkCompactCollector::StartSweepSpace(PagedSpace* space) {
-  Address space_top = space->top();
   space->ClearStats();
 
   int will_be_swept = 0;
@@ -3958,24 +3931,6 @@ void MarkCompactCollector::StartSweepSpace(PagedSpace* space) {
       continue;
     }
 
-    // We can not sweep black pages, since all mark bits are set for these
-    // pages.
-    if (p->IsFlagSet(Page::BLACK_PAGE)) {
-      p->ClearLiveness();
-      p->concurrent_sweeping_state().SetValue(Page::kSweepingDone);
-      p->ClearFlag(Page::BLACK_PAGE);
-      // Area above the high watermark is free.
-      Address free_start = p->HighWaterMark();
-      // Check if the space top was in this page, which means that the
-      // high watermark is not up-to-date.
-      if (free_start < space_top && space_top <= p->area_end()) {
-        free_start = space_top;
-      }
-      int size = static_cast<int>(p->area_end() - free_start);
-      space->Free(free_start, size);
-      continue;
-    }
-
     if (p->IsFlagSet(Page::NEVER_ALLOCATE_ON_PAGE)) {
       // We need to sweep the page to get it into an iterable state again. Note
       // that this adds unusable memory into the free list that is later on

src/heap/mark-compact.h

@@ -218,7 +218,19 @@ class MarkBitCellIterator BASE_EMBEDDED {
 
   inline void Advance() {
     cell_index_++;
-    cell_base_ += 32 * kPointerSize;
+    cell_base_ += Bitmap::kBitsPerCell * kPointerSize;
+  }
+
+  inline bool Advance(unsigned int new_cell_index) {
+    if (new_cell_index != cell_index_) {
+      DCHECK_GT(new_cell_index, cell_index_);
+      DCHECK_LE(new_cell_index, last_cell_index_);
+      unsigned int diff = new_cell_index - cell_index_;
+      cell_index_ = new_cell_index;
+      cell_base_ += diff * (Bitmap::kBitsPerCell * kPointerSize);
+      return true;
+    }
+    return false;
   }
 
   // Return the next mark bit cell. If there is no next it returns 0;
@@ -253,8 +265,6 @@ class LiveObjectIterator BASE_EMBEDDED {
         it_(chunk_),
         cell_base_(it_.CurrentCellBase()),
         current_cell_(*it_.CurrentCell()) {
-    // Black pages can not be iterated.
-    DCHECK(!chunk->IsFlagSet(Page::BLACK_PAGE));
   }
 
   HeapObject* Next();

src/heap/marking.h

@@ -106,8 +106,98 @@ class Bitmap {
     for (int i = 0; i < CellsCount(); i++) cells()[i] = 0;
   }
 
-  void SetAllBits() {
-    for (int i = 0; i < CellsCount(); i++) cells()[i] = 0xffffffff;
+  // Sets all bits in the range [start_index, end_index).
+  void SetRange(uint32_t start_index, uint32_t end_index) {
+    unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index);
+
+    unsigned int end_cell_index = end_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType end_index_mask = 1u << Bitmap::IndexInCell(end_index);
+
+    if (start_cell_index != end_cell_index) {
+      // Firstly, fill all bits from the start address to the end of the first
+      // cell with 1s.
+      cells()[start_cell_index] |= ~(start_index_mask - 1);
+      // Then fill all in between cells with 1s.
+      for (unsigned int i = start_cell_index + 1; i < end_cell_index; i++) {
+        cells()[i] = ~0u;
+      }
+      // Finally, fill all bits until the end address in the last cell with 1s.
+      cells()[end_cell_index] |= (end_index_mask - 1);
+    } else {
+      cells()[start_cell_index] |= end_index_mask - start_index_mask;
+    }
+  }
+
+  // Clears all bits in the range [start_index, end_index).
+  void ClearRange(uint32_t start_index, uint32_t end_index) {
+    unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index);
+
+    unsigned int end_cell_index = end_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType end_index_mask = 1u << Bitmap::IndexInCell(end_index);
+
+    if (start_cell_index != end_cell_index) {
+      // Firstly, fill all bits from the start address to the end of the first
+      // cell with 0s.
+      cells()[start_cell_index] &= (start_index_mask - 1);
+      // Then fill all in between cells with 0s.
+      for (unsigned int i = start_cell_index + 1; i < end_cell_index; i++) {
+        cells()[i] = 0;
+      }
+      // Finally, set all bits until the end address in the last cell with 0s.
+      cells()[end_cell_index] &= ~(end_index_mask - 1);
+    } else {
+      cells()[start_cell_index] &= ~(end_index_mask - start_index_mask);
+    }
+  }
+
+  // Returns true if all bits in the range [start_index, end_index) are set.
+  bool AllBitsSetInRange(uint32_t start_index, uint32_t end_index) {
+    unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index);
+
+    unsigned int end_cell_index = end_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType end_index_mask = 1u << Bitmap::IndexInCell(end_index);
+
+    MarkBit::CellType matching_mask;
+    if (start_cell_index != end_cell_index) {
+      matching_mask = ~(start_index_mask - 1);
+      if ((cells()[start_cell_index] & matching_mask) != matching_mask) {
+        return false;
+      }
+      for (unsigned int i = start_cell_index + 1; i < end_cell_index; i++) {
+        if (cells()[i] != ~0u) return false;
+      }
+      matching_mask = (end_index_mask - 1);
+      return ((cells()[end_cell_index] & matching_mask) == matching_mask);
+    } else {
+      matching_mask = end_index_mask - start_index_mask;
+      return (cells()[end_cell_index] & matching_mask) == matching_mask;
+    }
+  }
+
+  // Returns true if all bits in the range [start_index, end_index) are cleared.
+  bool AllBitsClearInRange(uint32_t start_index, uint32_t end_index) {
+    unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index);
+
+    unsigned int end_cell_index = end_index >> Bitmap::kBitsPerCellLog2;
+    MarkBit::CellType end_index_mask = 1u << Bitmap::IndexInCell(end_index);
+
+    MarkBit::CellType matching_mask;
+    if (start_cell_index != end_cell_index) {
+      matching_mask = ~(start_index_mask - 1);
+      if ((cells()[start_cell_index] & matching_mask)) return false;
+      for (unsigned int i = start_cell_index + 1; i < end_cell_index; i++) {
+        if (cells()[i]) return false;
+      }
+      matching_mask = (end_index_mask - 1);
+      return !(cells()[end_cell_index] & matching_mask);
+    } else {
+      matching_mask = end_index_mask - start_index_mask;
+      return !(cells()[end_cell_index] & matching_mask);
+    }
   }
 
   static void PrintWord(uint32_t word, uint32_t himask = 0) {
@@ -175,23 +265,6 @@ class Bitmap {
     }
     return true;
   }
-
-  // Clears all bits starting from {cell_base_index} up to and excluding
-  // {index}. Note that {cell_base_index} is required to be cell aligned.
-  void ClearRange(uint32_t cell_base_index, uint32_t index) {
-    DCHECK_EQ(IndexInCell(cell_base_index), 0u);
-    DCHECK_GE(index, cell_base_index);
-    uint32_t start_cell_index = IndexToCell(cell_base_index);
-    uint32_t end_cell_index = IndexToCell(index);
-    DCHECK_GE(end_cell_index, start_cell_index);
-    // Clear all cells till the cell containing the last index.
-    for (uint32_t i = start_cell_index; i < end_cell_index; i++) {
-      cells()[i] = 0;
-    }
-    // Clear all bits in the last cell till the last bit before index.
-    uint32_t clear_mask = ~((1u << IndexInCell(index)) - 1);
-    cells()[end_cell_index] &= clear_mask;
-  }
 };
 
 class Marking : public AllStatic {

src/heap/scavenger.cc

@@ -138,7 +138,7 @@ class ScavengingVisitor : public StaticVisitorBase {
     }
 
     if (marks_handling == TRANSFER_MARKS) {
-      if (IncrementalMarking::TransferColor(source, target)) {
+      if (IncrementalMarking::TransferColor(source, target, size)) {
         MemoryChunk::IncrementLiveBytesFromGC(target, size);
       }
     }

src/heap/spaces-inl.h

@@ -34,7 +34,6 @@ NewSpacePageRange::NewSpacePageRange(Address start, Address limit)
   SemiSpace::AssertValidRange(start, limit);
 }
 
-
 // -----------------------------------------------------------------------------
 // SemiSpaceIterator
 
@@ -242,7 +241,6 @@ void MemoryChunk::ResetLiveBytes() {
 }
 
 void MemoryChunk::IncrementLiveBytes(int by) {
-  if (IsFlagSet(BLACK_PAGE)) return;
   if (FLAG_trace_live_bytes) {
     PrintIsolate(
         heap()->isolate(), "live-bytes: update page=%p delta=%d %d->%d\n",
@@ -444,6 +442,12 @@ AllocationResult PagedSpace::AllocateRawUnaligned(
     if (object == NULL) {
       object = SlowAllocateRaw(size_in_bytes);
     }
+    if (object != NULL) {
+      if (heap()->incremental_marking()->black_allocation()) {
+        Marking::MarkBlack(ObjectMarking::MarkBitFrom(object));
+        MemoryChunk::IncrementLiveBytesFromGC(object, size_in_bytes);
+      }
+    }
   }
 
   if (object != NULL) {

src/heap/spaces.cc

@@ -1229,18 +1229,6 @@ bool PagedSpace::Expand() {
   // Pages created during bootstrapping may contain immortal immovable objects.
   if (!heap()->deserialization_complete()) p->MarkNeverEvacuate();
 
-  // When incremental marking was activated, old space pages are allocated
-  // black.
-  if (heap()->incremental_marking()->black_allocation() &&
-      identity() == OLD_SPACE) {
-    p->markbits()->SetAllBits();
-    p->SetFlag(Page::BLACK_PAGE);
-    if (FLAG_trace_incremental_marking) {
-      PrintIsolate(heap()->isolate(), "Added black page %p\n",
-                   static_cast<void*>(p));
-    }
-  }
-
   DCHECK(Capacity() <= heap()->MaxOldGenerationSize());
 
   p->InsertAfter(anchor_.prev_page());
@@ -1265,6 +1253,50 @@ void PagedSpace::ResetFreeListStatistics() {
   }
 }
 
+void PagedSpace::SetAllocationInfo(Address top, Address limit) {
+  SetTopAndLimit(top, limit);
+  if (top != nullptr && top != limit &&
+      heap()->incremental_marking()->black_allocation()) {
+    Page* page = Page::FromAddress(top);
+    page->markbits()->SetRange(page->AddressToMarkbitIndex(top),
+                               page->AddressToMarkbitIndex(limit));
+    page->IncrementLiveBytes(static_cast<int>(limit - top));
+  }
+}
+
+void PagedSpace::MarkAllocationInfoBlack() {
+  DCHECK(heap()->incremental_marking()->black_allocation());
+  Address current_top = top();
+  Address current_limit = limit();
+  if (current_top != nullptr && current_top != current_limit) {
+    Page* page = Page::FromAddress(current_top);
+    page->markbits()->SetRange(page->AddressToMarkbitIndex(current_top),
+                               page->AddressToMarkbitIndex(current_limit));
+    page->IncrementLiveBytes(static_cast<int>(current_limit - current_top));
+  }
+}
+
+// Empty space allocation info, returning unused area to free list.
+void PagedSpace::EmptyAllocationInfo() {
+  // Mark the old linear allocation area with a free space map so it can be
+  // skipped when scanning the heap.
+  Address current_top = top();
+  Address current_limit = limit();
+  if (current_top == nullptr) {
+    DCHECK(current_limit == nullptr);
+    return;
+  }
+  int old_linear_size = static_cast<int>(current_limit - current_top);
+  SetTopAndLimit(NULL, NULL);
+  if (current_top != current_limit &&
+      heap()->incremental_marking()->black_allocation()) {
+    Page* page = Page::FromAddress(current_top);
+    page->markbits()->ClearRange(page->AddressToMarkbitIndex(current_top),
+                                 page->AddressToMarkbitIndex(current_limit));
+    page->IncrementLiveBytes(-static_cast<int>(current_limit - current_top));
+  }
+  Free(current_top, old_linear_size);
+}
 
 void PagedSpace::IncreaseCapacity(int size) {
   accounting_stats_.ExpandSpace(size);
@@ -1331,8 +1363,7 @@ void PagedSpace::Verify(ObjectVisitor* visitor) {
       // All the interior pointers should be contained in the heap.
       int size = object->Size();
       object->IterateBody(map->instance_type(), size, visitor);
-      if (!page->IsFlagSet(Page::BLACK_PAGE) &&
-          Marking::IsBlack(ObjectMarking::MarkBitFrom(object))) {
+      if (Marking::IsBlack(ObjectMarking::MarkBitFrom(object))) {
         black_size += size;
       }
 
@@ -2429,8 +2460,7 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
   // Mark the old linear allocation area with a free space map so it can be
   // skipped when scanning the heap.  This also puts it back in the free list
   // if it is big enough.
-  owner_->Free(owner_->top(), old_linear_size);
-  owner_->SetTopAndLimit(nullptr, nullptr);
+  owner_->EmptyAllocationInfo();
 
   owner_->heap()->incremental_marking()->OldSpaceStep(size_in_bytes -
                                                       old_linear_size);
@@ -2464,8 +2494,8 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
     // Keep the linear allocation area empty if requested to do so, just
     // return area back to the free list instead.
     owner_->Free(new_node->address() + size_in_bytes, bytes_left);
-    owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
-                           new_node->address() + size_in_bytes);
+    owner_->SetAllocationInfo(new_node->address() + size_in_bytes,
+                              new_node->address() + size_in_bytes);
   } else if (bytes_left > kThreshold &&
              owner_->heap()->incremental_marking()->IsMarkingIncomplete() &&
              FLAG_incremental_marking) {
@@ -2475,14 +2505,15 @@ HeapObject* FreeList::Allocate(int size_in_bytes) {
     // we want to do another increment until the linear area is used up.
     owner_->Free(new_node->address() + size_in_bytes + linear_size,
                  new_node_size - size_in_bytes - linear_size);
-    owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
-                           new_node->address() + size_in_bytes + linear_size);
+    owner_->SetAllocationInfo(
+        new_node->address() + size_in_bytes,
+        new_node->address() + size_in_bytes + linear_size);
   } else {
     DCHECK(bytes_left >= 0);
     // Normally we give the rest of the node to the allocator as its new
     // linear allocation area.
-    owner_->SetTopAndLimit(new_node->address() + size_in_bytes,
-                           new_node->address() + new_node_size);
+    owner_->SetAllocationInfo(new_node->address() + size_in_bytes,
+                              new_node->address() + new_node_size);
   }
 
   owner_->AllocationStep(new_node->address(), size_in_bytes);
@@ -2872,6 +2903,11 @@ AllocationResult LargeObjectSpace::AllocateRaw(int object_size,
 
   heap()->incremental_marking()->OldSpaceStep(object_size);
   AllocationStep(object->address(), object_size);
+
+  if (heap()->incremental_marking()->black_allocation()) {
+    Marking::MarkBlack(ObjectMarking::MarkBitFrom(object));
+    MemoryChunk::IncrementLiveBytesFromGC(object, object_size);
+  }
   return object;
 }
 

src/heap/spaces.h

@@ -250,11 +250,6 @@ class MemoryChunk {
     // within the new space during evacuation.
     PAGE_NEW_NEW_PROMOTION,
 
-    // A black page has all mark bits set to 1 (black). A black page currently
-    // cannot be iterated because it is not swept. Moreover live bytes are also
-    // not updated.
-    BLACK_PAGE,
-
     // This flag is intended to be used for testing. Works only when both
     // FLAG_stress_compaction and FLAG_manual_evacuation_candidates_selection
     // are set. It forces the page to become an evacuation candidate at next
@@ -429,12 +424,10 @@ class MemoryChunk {
 
   int LiveBytes() {
     DCHECK_LE(static_cast<unsigned>(live_byte_count_), size_);
-    DCHECK(!IsFlagSet(BLACK_PAGE) || live_byte_count_ == 0);
     return live_byte_count_;
   }
 
   void SetLiveBytes(int live_bytes) {
-    if (IsFlagSet(BLACK_PAGE)) return;
     DCHECK_GE(live_bytes, 0);
     DCHECK_LE(static_cast<size_t>(live_bytes), size_);
     live_byte_count_ = live_bytes;
@@ -2075,14 +2068,12 @@ class PagedSpace : public Space {
     allocation_info_.Reset(top, limit);
   }
 
+  void SetAllocationInfo(Address top, Address limit);
+
   // Empty space allocation info, returning unused area to free list.
-  void EmptyAllocationInfo() {
-    // Mark the old linear allocation area with a free space map so it can be
-    // skipped when scanning the heap.
-    int old_linear_size = static_cast<int>(limit() - top());
-    Free(top(), old_linear_size);
-    SetTopAndLimit(NULL, NULL);
-  }
+  void EmptyAllocationInfo();
+
+  void MarkAllocationInfoBlack();
 
   void Allocate(int bytes) { accounting_stats_.AllocateBytes(bytes); }
 

src/ia32/assembler-ia32-inl.h

@@ -139,6 +139,8 @@ void RelocInfo::set_target_object(Object* target,
       host() != NULL &&
       target->IsHeapObject()) {
     host()->GetHeap()->RecordWriteIntoCode(host(), this, target);
+    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(
+        host(), this, HeapObject::cast(target));
   }
 }
 

src/objects-inl.h

@@ -1995,10 +1995,9 @@ void WeakCell::initialize(HeapObject* val) {
   // We just have to execute the generational barrier here because we never
   // mark through a weak cell and collect evacuation candidates when we process
   // all weak cells.
-  WriteBarrierMode mode =
-      Page::FromAddress(this->address())->IsFlagSet(Page::BLACK_PAGE)
-          ? UPDATE_WRITE_BARRIER
-          : UPDATE_WEAK_WRITE_BARRIER;
+  WriteBarrierMode mode = Marking::IsBlack(ObjectMarking::MarkBitFrom(this))
+                              ? UPDATE_WRITE_BARRIER
+                              : UPDATE_WEAK_WRITE_BARRIER;
   CONDITIONAL_WRITE_BARRIER(GetHeap(), this, kValueOffset, val, mode);
 }
 

test/cctest/heap/test-heap.cc

@@ -6786,6 +6786,43 @@ TEST(Regress615489) {
   CHECK_LE(size_after, size_before);
 }
 
+TEST(LeftTrimFixedArrayInBlackArea) {
+  FLAG_black_allocation = true;
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Heap* heap = CcTest::heap();
+  Isolate* isolate = heap->isolate();
+  heap->CollectAllGarbage();
+
+  i::MarkCompactCollector* collector = heap->mark_compact_collector();
+  i::IncrementalMarking* marking = heap->incremental_marking();
+  if (collector->sweeping_in_progress()) {
+    collector->EnsureSweepingCompleted();
+  }
+  CHECK(marking->IsMarking() || marking->IsStopped());
+  if (marking->IsStopped()) {
+    heap->StartIncrementalMarking();
+  }
+  CHECK(marking->IsMarking());
+  marking->StartBlackAllocationForTesting();
+
+  // Ensure that we allocate a new page, set up a bump pointer area, and
+  // perform the allocation in a black area.
+  heap::SimulateFullSpace(heap->old_space());
+  isolate->factory()->NewFixedArray(4, TENURED);
+  Handle<FixedArray> array = isolate->factory()->NewFixedArray(50, TENURED);
+  CHECK(heap->old_space()->Contains(*array));
+  CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(*array)));
+
+  // Now left trim the allocated black area. A filler has to be installed
+  // for the trimmed area and all mark bits of the trimmed area have to be
+  // cleared.
+  FixedArrayBase* trimmed = heap->LeftTrimFixedArray(*array, 10);
+  CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(trimmed)));
+
+  heap::GcAndSweep(heap, OLD_SPACE);
+}
+
 TEST(Regress618958) {
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());

test/unittests/heap/marking-unittest.cc

@@ -110,5 +110,51 @@ TEST(Marking, TransitionWhiteGreyBlackGrey) {
   free(bitmap);
 }
 
+TEST(Marking, SetAndClearRange) {
+  Bitmap* bitmap = reinterpret_cast<Bitmap*>(
+      calloc(Bitmap::kSize / kPointerSize, kPointerSize));
+  for (int i = 0; i < 3; i++) {
+    bitmap->SetRange(i, Bitmap::kBitsPerCell + i);
+    CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[0], 0xffffffff << i);
+    CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[1], (1 << i) - 1);
+    bitmap->ClearRange(i, Bitmap::kBitsPerCell + i);
+    CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[0], 0x0);
+    CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[1], 0x0);
+  }
+  free(bitmap);
+}
+
+TEST(Marking, ClearMultipleRanges) {
+  Bitmap* bitmap = reinterpret_cast<Bitmap*>(
+      calloc(Bitmap::kSize / kPointerSize, kPointerSize));
+  CHECK(bitmap->AllBitsClearInRange(0, Bitmap::kBitsPerCell * 3));
+  bitmap->SetRange(0, Bitmap::kBitsPerCell * 3);
+  CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[0], 0xffffffff);
+  CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[1], 0xffffffff);
+  CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[2], 0xffffffff);
+  CHECK(bitmap->AllBitsSetInRange(0, Bitmap::kBitsPerCell * 3));
+  bitmap->ClearRange(Bitmap::kBitsPerCell / 2, Bitmap::kBitsPerCell);
+  bitmap->ClearRange(Bitmap::kBitsPerCell,
+                     Bitmap::kBitsPerCell + Bitmap::kBitsPerCell / 2);
+  bitmap->ClearRange(Bitmap::kBitsPerCell * 2 + 8,
+                     Bitmap::kBitsPerCell * 2 + 16);
+  bitmap->ClearRange(Bitmap::kBitsPerCell * 2 + 24, Bitmap::kBitsPerCell * 3);
+  CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[0], 0xffff);
+  CHECK(bitmap->AllBitsSetInRange(0, Bitmap::kBitsPerCell / 2));
+  CHECK(bitmap->AllBitsClearInRange(Bitmap::kBitsPerCell / 2,
+                                    Bitmap::kBitsPerCell));
+  CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[1], 0xffff0000);
+  CHECK(
+      bitmap->AllBitsSetInRange(Bitmap::kBitsPerCell + Bitmap::kBitsPerCell / 2,
+                                2 * Bitmap::kBitsPerCell));
+  CHECK(bitmap->AllBitsClearInRange(
+      Bitmap::kBitsPerCell, Bitmap::kBitsPerCell + Bitmap::kBitsPerCell / 2));
+  CHECK_EQ(reinterpret_cast<uint32_t*>(bitmap)[2], 0xff00ff);
+  CHECK(bitmap->AllBitsSetInRange(2 * Bitmap::kBitsPerCell,
+                                  2 * Bitmap::kBitsPerCell + 8));
+  CHECK(bitmap->AllBitsClearInRange(2 * Bitmap::kBitsPerCell + 24,
+                                    Bitmap::kBitsPerCell * 3));
+  free(bitmap);
+}
 }  // namespace internal
 }  // namespace v8