[heap] Temporarily use old live object iterator to investigate Win 10 memory regression.

BUG=chromium:633537

Review-Url: https://codereview.chromium.org/2205373002
Cr-Commit-Position: refs/heads/master@{#38311}

src/heap/mark-compact-inl.h

@@ -148,66 +148,25 @@ HeapObject* LiveObjectIterator<T>::Next() {
         second_bit_index = 0x1;
         // The overlapping case; there has to exist a cell after the current
         // cell.
-        // However, if there is a black area at the end of the page, and the
-        // last word is a one word filler, we are not allowed to advance. In
-        // that case we can return immediately.
-        if (it_.Done()) {
-          DCHECK(HeapObject::FromAddress(addr)->map() ==
-                 HeapObject::FromAddress(addr)
-                     ->GetHeap()
-                     ->one_pointer_filler_map());
-          return nullptr;
-        }
+        DCHECK(!it_.Done());
         it_.Advance();
         cell_base_ = it_.CurrentCellBase();
         current_cell_ = *it_.CurrentCell();
       }
-
-      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;
-        // One word filler objects do not borrow the second mark bit. We have
-        // to jump over the advancing and clearing part.
-        // Note that we know that we are at a one word filler when
-        // object_start + object_size - kPointerSize == object_start.
-        if (addr != end) {
-          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)) {
+      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) {
         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) {
-        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 (object != nullptr) break;
     }
-
     if (current_cell_ == 0) {
       if (!it_.Done()) {
         it_.Advance();

test/cctest/heap/test-heap.cc

@@ -6786,164 +6786,6 @@ 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(ContinuousLeftTrimFixedArrayInBlackArea) {
-  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(10, TENURED);
-
-  // Allocate the fixed array that will be trimmed later.
-  Handle<FixedArray> array = isolate->factory()->NewFixedArray(100, TENURED);
-  Address start_address = array->address();
-  Address end_address = start_address + array->Size();
-  Page* page = Page::FromAddress(start_address);
-  CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(*array)));
-  CHECK(page->markbits()->AllBitsSetInRange(
-      page->AddressToMarkbitIndex(start_address),
-      page->AddressToMarkbitIndex(end_address)));
-  CHECK(heap->old_space()->Contains(*array));
-
-  FixedArrayBase* previous = *array;
-  FixedArrayBase* trimmed;
-
-  // First trim in one word steps.
-  for (int i = 0; i < 10; i++) {
-    trimmed = heap->LeftTrimFixedArray(previous, 1);
-    HeapObject* filler = HeapObject::FromAddress(previous->address());
-    CHECK(filler->IsFiller());
-    CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(trimmed)));
-    CHECK(Marking::IsImpossible(ObjectMarking::MarkBitFrom(previous)));
-    previous = trimmed;
-  }
-
-  // Then trim in two and three word steps.
-  for (int i = 2; i <= 3; i++) {
-    for (int j = 0; j < 10; j++) {
-      trimmed = heap->LeftTrimFixedArray(previous, i);
-      HeapObject* filler = HeapObject::FromAddress(previous->address());
-      CHECK(filler->IsFiller());
-      CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(trimmed)));
-      CHECK(Marking::IsWhite(ObjectMarking::MarkBitFrom(previous)));
-      previous = trimmed;
-    }
-  }
-
-  heap::GcAndSweep(heap, OLD_SPACE);
-}
-
-TEST(ContinuousRightTrimFixedArrayInBlackArea) {
-  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(10, TENURED);
-
-  // Allocate the fixed array that will be trimmed later.
-  Handle<FixedArray> array = isolate->factory()->NewFixedArray(100, TENURED);
-  Address start_address = array->address();
-  Address end_address = start_address + array->Size();
-  Page* page = Page::FromAddress(start_address);
-  CHECK(Marking::IsBlack(ObjectMarking::MarkBitFrom(*array)));
-  CHECK(page->markbits()->AllBitsSetInRange(
-      page->AddressToMarkbitIndex(start_address),
-      page->AddressToMarkbitIndex(end_address)));
-  CHECK(heap->old_space()->Contains(*array));
-
-  // Trim it once by one word to make checking for white marking color uniform.
-  Address previous = end_address - kPointerSize;
-  heap->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>(*array, 1);
-  HeapObject* filler = HeapObject::FromAddress(previous);
-  CHECK(filler->IsFiller());
-  CHECK(Marking::IsImpossible(ObjectMarking::MarkBitFrom(previous)));
-
-  // Trim 10 times by one, two, and three word.
-  for (int i = 1; i <= 3; i++) {
-    for (int j = 0; j < 10; j++) {
-      previous -= kPointerSize * i;
-      heap->RightTrimFixedArray<Heap::SEQUENTIAL_TO_SWEEPER>(*array, i);
-      HeapObject* filler = HeapObject::FromAddress(previous);
-      CHECK(filler->IsFiller());
-      CHECK(Marking::IsWhite(ObjectMarking::MarkBitFrom(previous)));
-    }
-  }
-
-  heap::GcAndSweep(heap, OLD_SPACE);
-}
-
 TEST(Regress618958) {
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());