Reland "Merge old data and pointer space."

src/heap/mark-compact.cc

 // 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/base/atomicops.h"
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 117 matching lines @@
   PageIterator it(space);
 
   while (it.has_next()) {
     Page* p = it.next();
     VerifyMarking(space->heap(), p->area_start(), p->area_end());
   }
 }
 
 
 static void VerifyMarking(Heap* heap) {
-  VerifyMarking(heap->old_pointer_space());
-  VerifyMarking(heap->old_data_space());
+  VerifyMarking(heap->old_space());
   VerifyMarking(heap->code_space());
   VerifyMarking(heap->cell_space());
   VerifyMarking(heap->map_space());
   VerifyMarking(heap->new_space());
 
   VerifyMarkingVisitor visitor(heap);
 
   LargeObjectIterator it(heap->lo_space());
   for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
     if (MarkCompactCollector::IsMarked(obj)) {
@@ skipping 43 matching lines @@
     while (current < limit) {
       HeapObject* object = HeapObject::FromAddress(current);
       object->Iterate(&visitor);
       current += object->Size();
     }
   }
 }
 
 
 static void VerifyEvacuation(Heap* heap, PagedSpace* space) {
-  if (FLAG_use_allocation_folding &&
-      (space == heap->old_pointer_space() || space == heap->old_data_space())) {
+  if (FLAG_use_allocation_folding && (space == heap->old_space())) {
     return;
   }
   PageIterator it(space);
 
   while (it.has_next()) {
     Page* p = it.next();
     if (p->IsEvacuationCandidate()) continue;
     VerifyEvacuation(p);
   }
 }
 
 
 static void VerifyEvacuation(Heap* heap) {
-  VerifyEvacuation(heap, heap->old_pointer_space());
-  VerifyEvacuation(heap, heap->old_data_space());
+  VerifyEvacuation(heap, heap->old_space());
   VerifyEvacuation(heap, heap->code_space());
   VerifyEvacuation(heap, heap->cell_space());
   VerifyEvacuation(heap, heap->map_space());
   VerifyEvacuation(heap->new_space());
 
   VerifyEvacuationVisitor visitor;
   heap->IterateStrongRoots(&visitor, VISIT_ALL);
 }
 #endif  // VERIFY_HEAP
 
 
 void MarkCompactCollector::SetUp() {
-  free_list_old_data_space_.Reset(new FreeList(heap_->old_data_space()));
-  free_list_old_pointer_space_.Reset(new FreeList(heap_->old_pointer_space()));
+  free_list_old_space_.Reset(new FreeList(heap_->old_space()));
 }
 
 
 void MarkCompactCollector::TearDown() {
   AbortCompaction();
   delete marking_deque_memory_;
 }
 
 
 void MarkCompactCollector::AddEvacuationCandidate(Page* p) {
@@ skipping 10 matching lines @@
   PrintF("[%s]: %d pages, %d (%.1f%%) free\n",
          AllocationSpaceName(space->identity()), number_of_pages,
          static_cast<int>(free), static_cast<double>(free) * 100 / reserved);
 }
 
 
 bool MarkCompactCollector::StartCompaction(CompactionMode mode) {
   if (!compacting_) {
     DCHECK(evacuation_candidates_.length() == 0);
 
-    CollectEvacuationCandidates(heap()->old_pointer_space());
-    CollectEvacuationCandidates(heap()->old_data_space());
+    CollectEvacuationCandidates(heap()->old_space());
 
     if (FLAG_compact_code_space && (mode == NON_INCREMENTAL_COMPACTION ||
                                     FLAG_incremental_code_compaction)) {
       CollectEvacuationCandidates(heap()->code_space());
     } else if (FLAG_trace_fragmentation) {
       TraceFragmentation(heap()->code_space());
     }
 
     if (FLAG_trace_fragmentation) {
       TraceFragmentation(heap()->map_space());
       TraceFragmentation(heap()->cell_space());
     }
 
-    heap()->old_pointer_space()->EvictEvacuationCandidatesFromFreeLists();
-    heap()->old_data_space()->EvictEvacuationCandidatesFromFreeLists();
+    heap()->old_space()->EvictEvacuationCandidatesFromFreeLists();
     heap()->code_space()->EvictEvacuationCandidatesFromFreeLists();
 
     compacting_ = evacuation_candidates_.length() > 0;
   }
 
   return compacting_;
 }
 
 
 void MarkCompactCollector::ClearInvalidSlotsBufferEntries(PagedSpace* space) {
   PageIterator it(space);
   while (it.has_next()) {
     Page* p = it.next();
     SlotsBuffer::RemoveInvalidSlots(heap_, p->slots_buffer());
   }
 }
 
 
 void MarkCompactCollector::ClearInvalidStoreAndSlotsBufferEntries() {
   heap_->store_buffer()->ClearInvalidStoreBufferEntries();
 
-  ClearInvalidSlotsBufferEntries(heap_->old_pointer_space());
-  ClearInvalidSlotsBufferEntries(heap_->old_data_space());
+  ClearInvalidSlotsBufferEntries(heap_->old_space());
   ClearInvalidSlotsBufferEntries(heap_->code_space());
   ClearInvalidSlotsBufferEntries(heap_->cell_space());
   ClearInvalidSlotsBufferEntries(heap_->map_space());
 
   LargeObjectIterator it(heap_->lo_space());
   for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) {
     MemoryChunk* chunk = MemoryChunk::FromAddress(object->address());
     SlotsBuffer::RemoveInvalidSlots(heap_, chunk->slots_buffer());
   }
 }
 
 
 #ifdef VERIFY_HEAP
 static void VerifyValidSlotsBufferEntries(Heap* heap, PagedSpace* space) {
   PageIterator it(space);
   while (it.has_next()) {
     Page* p = it.next();
     SlotsBuffer::VerifySlots(heap, p->slots_buffer());
   }
 }
 
 
 static void VerifyValidStoreAndSlotsBufferEntries(Heap* heap) {
   heap->store_buffer()->VerifyValidStoreBufferEntries();
 
-  VerifyValidSlotsBufferEntries(heap, heap->old_pointer_space());
-  VerifyValidSlotsBufferEntries(heap, heap->old_data_space());
+  VerifyValidSlotsBufferEntries(heap, heap->old_space());
   VerifyValidSlotsBufferEntries(heap, heap->code_space());
   VerifyValidSlotsBufferEntries(heap, heap->cell_space());
   VerifyValidSlotsBufferEntries(heap, heap->map_space());
 
   LargeObjectIterator it(heap->lo_space());
   for (HeapObject* object = it.Next(); object != NULL; object = it.Next()) {
     MemoryChunk* chunk = MemoryChunk::FromAddress(object->address());
     SlotsBuffer::VerifySlots(heap, chunk->slots_buffer());
   }
 }
@@ skipping 70 matching lines @@
 
   while (it.has_next()) {
     NewSpacePage* p = it.next();
     CHECK(p->markbits()->IsClean());
     CHECK_EQ(0, p->LiveBytes());
   }
 }
 
 
 void MarkCompactCollector::VerifyMarkbitsAreClean() {
-  VerifyMarkbitsAreClean(heap_->old_pointer_space());
-  VerifyMarkbitsAreClean(heap_->old_data_space());
+  VerifyMarkbitsAreClean(heap_->old_space());
   VerifyMarkbitsAreClean(heap_->code_space());
   VerifyMarkbitsAreClean(heap_->cell_space());
   VerifyMarkbitsAreClean(heap_->map_space());
   VerifyMarkbitsAreClean(heap_->new_space());
 
   LargeObjectIterator it(heap_->lo_space());
   for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
     MarkBit mark_bit = Marking::MarkBitFrom(obj);
     CHECK(Marking::IsWhite(mark_bit));
     CHECK_EQ(0, Page::FromAddress(obj->address())->LiveBytes());
@@ skipping 37 matching lines @@
 
   while (it.has_next()) {
     Bitmap::Clear(it.next());
   }
 }
 
 
 void MarkCompactCollector::ClearMarkbits() {
   ClearMarkbitsInPagedSpace(heap_->code_space());
   ClearMarkbitsInPagedSpace(heap_->map_space());
-  ClearMarkbitsInPagedSpace(heap_->old_pointer_space());
-  ClearMarkbitsInPagedSpace(heap_->old_data_space());
+  ClearMarkbitsInPagedSpace(heap_->old_space());
   ClearMarkbitsInPagedSpace(heap_->cell_space());
   ClearMarkbitsInNewSpace(heap_->new_space());
 
   LargeObjectIterator it(heap_->lo_space());
   for (HeapObject* obj = it.Next(); obj != NULL; obj = it.Next()) {
     MarkBit mark_bit = Marking::MarkBitFrom(obj);
     mark_bit.Clear();
     mark_bit.Next().Clear();
     Page::FromAddress(obj->address())->ResetProgressBar();
     Page::FromAddress(obj->address())->ResetLiveBytes();
@@ skipping 15 matching lines @@
   }
 
   Heap* heap_;
   PagedSpace* space_;
 
   DISALLOW_COPY_AND_ASSIGN(SweeperTask);
 };
 
 
 void MarkCompactCollector::StartSweeperThreads() {
-  DCHECK(free_list_old_pointer_space_.get()->IsEmpty());
-  DCHECK(free_list_old_data_space_.get()->IsEmpty());
+  DCHECK(free_list_old_space_.get()->IsEmpty());
   V8::GetCurrentPlatform()->CallOnBackgroundThread(
-      new SweeperTask(heap(), heap()->old_data_space()),
-      v8::Platform::kShortRunningTask);
-  V8::GetCurrentPlatform()->CallOnBackgroundThread(
-      new SweeperTask(heap(), heap()->old_pointer_space()),
+      new SweeperTask(heap(), heap()->old_space()),
       v8::Platform::kShortRunningTask);
 }
 
 
 void MarkCompactCollector::EnsureSweepingCompleted() {
   DCHECK(sweeping_in_progress_ == true);
 
   // If sweeping is not completed or not running at all, we try to complete it
   // here.
   if (!heap()->concurrent_sweeping_enabled() || !IsSweepingCompleted()) {
-    SweepInParallel(heap()->paged_space(OLD_DATA_SPACE), 0);
-    SweepInParallel(heap()->paged_space(OLD_POINTER_SPACE), 0);
+    SweepInParallel(heap()->paged_space(OLD_SPACE), 0);
   }
   // Wait twice for both jobs.
   if (heap()->concurrent_sweeping_enabled()) {
     pending_sweeper_jobs_semaphore_.Wait();
-    pending_sweeper_jobs_semaphore_.Wait();
   }
   ParallelSweepSpacesComplete();
   sweeping_in_progress_ = false;
-  RefillFreeList(heap()->paged_space(OLD_DATA_SPACE));
-  RefillFreeList(heap()->paged_space(OLD_POINTER_SPACE));
-  heap()->paged_space(OLD_DATA_SPACE)->ResetUnsweptFreeBytes();
-  heap()->paged_space(OLD_POINTER_SPACE)->ResetUnsweptFreeBytes();
+  RefillFreeList(heap()->paged_space(OLD_SPACE));
+  heap()->paged_space(OLD_SPACE)->ResetUnsweptFreeBytes();
 
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap && !evacuation()) {
     VerifyEvacuation(heap_);
   }
 #endif
 }
 
 
 bool MarkCompactCollector::IsSweepingCompleted() {
   if (!pending_sweeper_jobs_semaphore_.WaitFor(
           base::TimeDelta::FromSeconds(0))) {
     return false;
   }
   pending_sweeper_jobs_semaphore_.Signal();
   return true;
 }
 
 
 void MarkCompactCollector::RefillFreeList(PagedSpace* space) {
   FreeList* free_list;
 
-  if (space == heap()->old_pointer_space()) {
-    free_list = free_list_old_pointer_space_.get();
-  } else if (space == heap()->old_data_space()) {
-    free_list = free_list_old_data_space_.get();
+  if (space == heap()->old_space()) {
+    free_list = free_list_old_space_.get();
   } else {
     // Any PagedSpace might invoke RefillFreeLists, so we need to make sure
-    // to only refill them for old data and pointer spaces.
+    // to only refill them for the old space.
     return;
   }
 
   intptr_t freed_bytes = space->free_list()->Concatenate(free_list);
   space->AddToAccountingStats(freed_bytes);
   space->DecrementUnsweptFreeBytes(freed_bytes);
 }
 
 
 void Marking::TransferMark(Address old_start, Address new_start) {
@@ skipping 33 matching lines @@
   ObjectColor new_color = Color(new_mark_bit);
   DCHECK(new_color == old_color);
 #endif
 }
 
 
 const char* AllocationSpaceName(AllocationSpace space) {
   switch (space) {
     case NEW_SPACE:
       return "NEW_SPACE";
-    case OLD_POINTER_SPACE:
-      return "OLD_POINTER_SPACE";
-    case OLD_DATA_SPACE:
-      return "OLD_DATA_SPACE";
+    case OLD_SPACE:
+      return "OLD_SPACE";
     case CODE_SPACE:
       return "CODE_SPACE";
     case MAP_SPACE:
       return "MAP_SPACE";
     case CELL_SPACE:
       return "CELL_SPACE";
     case LO_SPACE:
       return "LO_SPACE";
     default:
       UNREACHABLE();
@@ skipping 48 matching lines @@
     return 1;
   }
 
   if (ratio <= ratio_threshold) return 0;  // Not fragmented.
 
   return static_cast<int>(ratio - ratio_threshold);
 }
 
 
 void MarkCompactCollector::CollectEvacuationCandidates(PagedSpace* space) {
-  DCHECK(space->identity() == OLD_POINTER_SPACE ||
-         space->identity() == OLD_DATA_SPACE ||
-         space->identity() == CODE_SPACE);
+  DCHECK(space->identity() == OLD_SPACE || space->identity() == CODE_SPACE);
 
   static const int kMaxMaxEvacuationCandidates = 1000;
   int number_of_pages = space->CountTotalPages();
   int max_evacuation_candidates =
       static_cast<int>(std::sqrt(number_of_pages / 2.0) + 1);
 
   if (FLAG_stress_compaction || FLAG_always_compact) {
     max_evacuation_candidates = kMaxMaxEvacuationCandidates;
   }
 
@@ skipping 1162 matching lines @@
                                      (next_cell << (Bitmap::kBitsPerCell - 1)));
     } else {
       grey_objects = current_cell & (current_cell >> 1);
     }
 
     int offset = 0;
     while (grey_objects != 0) {
       int trailing_zeros = base::bits::CountTrailingZeros32(grey_objects);
       grey_objects >>= trailing_zeros;
       offset += trailing_zeros;
-      MarkBit markbit(cell, 1 << offset, false);
+      MarkBit markbit(cell, 1 << offset);
       DCHECK(Marking::IsGrey(markbit));
       Marking::GreyToBlack(markbit);
       Address addr = cell_base + offset * kPointerSize;
       HeapObject* object = HeapObject::FromAddress(addr);
       MemoryChunk::IncrementLiveBytesFromGC(object->address(), object->Size());
       marking_deque->PushBlack(object);
       if (marking_deque->IsFull()) return;
       offset += 2;
       grey_objects >>= 2;
     }
@@ skipping 203 matching lines @@
 // before sweeping completes.  If sweeping completes, there are no remaining
 // overflowed objects in the heap so the overflow flag on the markings stack
 // is cleared.
 void MarkCompactCollector::RefillMarkingDeque() {
   isolate()->CountUsage(v8::Isolate::UseCounterFeature::kMarkDequeOverflow);
   DCHECK(marking_deque_.overflowed());
 
   DiscoverGreyObjectsInNewSpace(heap(), &marking_deque_);
   if (marking_deque_.IsFull()) return;
 
-  DiscoverGreyObjectsInSpace(heap(), &marking_deque_,
-                             heap()->old_pointer_space());
-  if (marking_deque_.IsFull()) return;
-
-  DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->old_data_space());
+  DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->old_space());
   if (marking_deque_.IsFull()) return;
 
   DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->code_space());
   if (marking_deque_.IsFull()) return;
 
   DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->map_space());
   if (marking_deque_.IsFull()) return;
 
   DiscoverGreyObjectsInSpace(heap(), &marking_deque_, heap()->cell_space());
   if (marking_deque_.IsFull()) return;
@@ skipping 658 matching lines @@
 // to new space.  We should clear them to avoid encountering them during next
 // pointer iteration.  This is an issue if the store buffer overflows and we
 // have to scan the entire old space, including dead objects, looking for
 // pointers to new space.
 void MarkCompactCollector::MigrateObject(HeapObject* dst, HeapObject* src,
                                          int size, AllocationSpace dest) {
   Address dst_addr = dst->address();
   Address src_addr = src->address();
   DCHECK(heap()->AllowedToBeMigrated(src, dest));
   DCHECK(dest != LO_SPACE && size <= Page::kMaxRegularHeapObjectSize);
-  if (dest == OLD_POINTER_SPACE) {
+  if (dest == OLD_SPACE) {
     Address src_slot = src_addr;
     Address dst_slot = dst_addr;
     DCHECK(IsAligned(size, kPointerSize));
 
     bool may_contain_raw_values = src->MayContainRawValues();
 #if V8_DOUBLE_FIELDS_UNBOXING
     LayoutDescriptorHelper helper(src->map());
     bool has_only_tagged_fields = helper.all_fields_tagged();
 #endif
     for (int remaining = size / kPointerSize; remaining > 0; remaining--) {
@@ skipping 51 matching lines @@
       }
     }
   } else if (dest == CODE_SPACE) {
     PROFILE(isolate(), CodeMoveEvent(src_addr, dst_addr));
     heap()->MoveBlock(dst_addr, src_addr, size);
     SlotsBuffer::AddTo(&slots_buffer_allocator_, &migration_slots_buffer_,
                        SlotsBuffer::RELOCATED_CODE_OBJECT, dst_addr,
                        SlotsBuffer::IGNORE_OVERFLOW);
     Code::cast(dst)->Relocate(dst_addr - src_addr);
   } else {
-    DCHECK(dest == OLD_DATA_SPACE || dest == NEW_SPACE);
+    DCHECK(dest == NEW_SPACE);
     heap()->MoveBlock(dst_addr, src_addr, size);
   }
   heap()->OnMoveEvent(dst, src, size);
   Memory::Address_at(src_addr) = dst_addr;
 }
 
 
 // Visitor for updating pointers from live objects in old spaces to new space.
 // It does not expect to encounter pointers to dead objects.
 class PointersUpdatingVisitor : public ObjectVisitor {
@@ skipping 101 matching lines @@
   data[index++] = reinterpret_cast<uintptr_t>(slot);
   data[index++] = 0x15aaaaaaaaUL;
 
   Address slot_address = reinterpret_cast<Address>(slot);
 
   uintptr_t space_owner_id = 0xb001;
   if (heap->new_space()->ToSpaceContains(slot_address)) {
     space_owner_id = 1;
   } else if (heap->new_space()->FromSpaceContains(slot_address)) {
     space_owner_id = 2;
-  } else if (heap->old_pointer_space()->ContainsSafe(slot_address)) {
+  } else if (heap->old_space()->ContainsSafe(slot_address)) {
     space_owner_id = 3;
-  } else if (heap->old_data_space()->ContainsSafe(slot_address)) {
+  } else if (heap->code_space()->ContainsSafe(slot_address)) {
     space_owner_id = 4;
-  } else if (heap->code_space()->ContainsSafe(slot_address)) {
+  } else if (heap->map_space()->ContainsSafe(slot_address)) {
     space_owner_id = 5;
-  } else if (heap->map_space()->ContainsSafe(slot_address)) {
+  } else if (heap->cell_space()->ContainsSafe(slot_address)) {
     space_owner_id = 6;
-  } else if (heap->cell_space()->ContainsSafe(slot_address)) {
-    space_owner_id = 7;
   } else {
     // Lo space or other.
-    space_owner_id = 8;
+    space_owner_id = 7;
   }
   data[index++] = space_owner_id;
   data[index++] = 0x20aaaaaaaaUL;
 
   // Find map word lying near before the slot address (usually the map word is
   // at -3 words from the slot but just in case we look up further.
   Object** map_slot = slot;
   bool found = false;
   const int kMaxDistanceToMap = 64;
   for (int i = 0; i < kMaxDistanceToMap; i++, map_slot--) {
@@ skipping 70 matching lines @@
   }
 
   return String::cast(*p);
 }
 
 
 bool MarkCompactCollector::TryPromoteObject(HeapObject* object,
                                             int object_size) {
   DCHECK(object_size <= Page::kMaxRegularHeapObjectSize);
 
-  OldSpace* target_space = heap()->TargetSpace(object);
+  OldSpace* old_space = heap()->old_space();
 
-  DCHECK(target_space == heap()->old_pointer_space() ||
-         target_space == heap()->old_data_space());
   HeapObject* target;
-  AllocationResult allocation = target_space->AllocateRaw(object_size);
+  AllocationResult allocation = old_space->AllocateRaw(object_size);
   if (allocation.To(&target)) {
-    MigrateObject(target, object, object_size, target_space->identity());
+    MigrateObject(target, object, object_size, old_space->identity());
     heap()->IncrementPromotedObjectsSize(object_size);
     return true;
   }
 
   return false;
 }
 
 
 bool MarkCompactCollector::IsSlotInBlackObject(Page* p, Address slot,
                                                HeapObject** out_object) {
@@ skipping 490 matching lines @@
 
   return true;
 }
 
 
 static bool IsOnInvalidatedCodeObject(Address addr) {
   // We did not record any slots in large objects thus
   // we can safely go to the page from the slot address.
   Page* p = Page::FromAddress(addr);
 
-  // First check owner's identity because old pointer and old data spaces
-  // are swept lazily and might still have non-zero mark-bits on some
-  // pages.
+  // First check owner's identity because old space is swept concurrently or
+  // lazily and might still have non-zero mark-bits on some pages.
   if (p->owner()->identity() != CODE_SPACE) return false;
 
   // In code space only bits on evacuation candidates (but we don't record
   // any slots on them) and under invalidated code objects are non-zero.
   MarkBit mark_bit =
       p->markbits()->MarkBitFromIndex(Page::FastAddressToMarkbitIndex(addr));
 
   return mark_bit.Get();
 }
 
@@ skipping 158 matching lines @@
         if (list != NULL) list->Clear();
       } else {
         if (FLAG_gc_verbose) {
           PrintF("Sweeping 0x%" V8PRIxPTR " during evacuation.\n",
                  reinterpret_cast<intptr_t>(p));
         }
         PagedSpace* space = static_cast<PagedSpace*>(p->owner());
         p->ClearFlag(MemoryChunk::RESCAN_ON_EVACUATION);
 
         switch (space->identity()) {
-          case OLD_DATA_SPACE:
+          case OLD_SPACE:
             Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
                   IGNORE_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p,
                                                        &updating_visitor);
-            break;
-          case OLD_POINTER_SPACE:
-            Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
-                  IGNORE_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p,
-                                                       &updating_visitor);
             break;
           case CODE_SPACE:
             if (FLAG_zap_code_space) {
               Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
                     REBUILD_SKIP_LIST, ZAP_FREE_SPACE>(space, NULL, p,
                                                        &updating_visitor);
             } else {
               Sweep<SWEEP_AND_VISIT_LIVE_OBJECTS, SWEEP_ON_MAIN_THREAD,
                     REBUILD_SKIP_LIST, IGNORE_FREE_SPACE>(space, NULL, p,
                                                           &updating_visitor);
@@ skipping 487 matching lines @@
     max_freed_overall = Max(max_freed, max_freed_overall);
     if (p == space->end_of_unswept_pages()) break;
   }
   return max_freed_overall;
 }
 
 
 int MarkCompactCollector::SweepInParallel(Page* page, PagedSpace* space) {
   int max_freed = 0;
   if (page->TryParallelSweeping()) {
-    FreeList* free_list = space == heap()->old_pointer_space()
-                              ? free_list_old_pointer_space_.get()
-                              : free_list_old_data_space_.get();
+    FreeList* free_list = free_list_old_space_.get();
     FreeList private_free_list(space);
     max_freed = Sweep<SWEEP_ONLY, SWEEP_IN_PARALLEL, IGNORE_SKIP_LIST,
                       IGNORE_FREE_SPACE>(space, &private_free_list, page, NULL);
     free_list->Concatenate(&private_free_list);
   }
   return max_freed;
 }
 
 
 void MarkCompactCollector::SweepSpace(PagedSpace* space, SweeperType sweeper) {
@@ skipping 104 matching lines @@
   MoveEvacuationCandidatesToEndOfPagesList();
 
   // Noncompacting collections simply sweep the spaces to clear the mark
   // bits and free the nonlive blocks (for old and map spaces).  We sweep
   // the map space last because freeing non-live maps overwrites them and
   // the other spaces rely on possibly non-live maps to get the sizes for
   // non-live objects.
   {
     GCTracer::Scope sweep_scope(heap()->tracer(),
                                 GCTracer::Scope::MC_SWEEP_OLDSPACE);
-    {
-      SweepSpace(heap()->old_pointer_space(), CONCURRENT_SWEEPING);
-      SweepSpace(heap()->old_data_space(), CONCURRENT_SWEEPING);
-    }
+    { SweepSpace(heap()->old_space(), CONCURRENT_SWEEPING); }
     sweeping_in_progress_ = true;
     if (heap()->concurrent_sweeping_enabled()) {
       StartSweeperThreads();
     }
   }
   RemoveDeadInvalidatedCode();
 
   {
     GCTracer::Scope sweep_scope(heap()->tracer(),
                                 GCTracer::Scope::MC_SWEEP_CODE);
@@ skipping 47 matching lines @@
     if (p->parallel_sweeping() == MemoryChunk::SWEEPING_FINALIZE) {
       p->set_parallel_sweeping(MemoryChunk::SWEEPING_DONE);
       p->SetWasSwept();
     }
     DCHECK(p->parallel_sweeping() == MemoryChunk::SWEEPING_DONE);
   }
 }
 
 
 void MarkCompactCollector::ParallelSweepSpacesComplete() {
-  ParallelSweepSpaceComplete(heap()->old_pointer_space());
-  ParallelSweepSpaceComplete(heap()->old_data_space());
+  ParallelSweepSpaceComplete(heap()->old_space());
 }
 
 
 void MarkCompactCollector::EnableCodeFlushing(bool enable) {
   if (isolate()->debug()->is_loaded() ||
       isolate()->debug()->has_break_points()) {
     enable = false;
   }
 
   if (enable) {
@@ skipping 168 matching lines @@
   isolate()->CountUsage(v8::Isolate::UseCounterFeature::kSlotsBufferOverflow);
 
   // TODO(gc) If all evacuation candidates are too popular we
   // should stop slots recording entirely.
   page->ClearEvacuationCandidate();
 
   // We were not collecting slots on this page that point
   // to other evacuation candidates thus we have to
   // rescan the page after evacuation to discover and update all
   // pointers to evacuated objects.
-  if (page->owner()->identity() == OLD_DATA_SPACE) {
-    evacuation_candidates_.RemoveElement(page);
-  } else {
-    page->SetFlag(Page::RESCAN_ON_EVACUATION);
-  }
+  page->SetFlag(Page::RESCAN_ON_EVACUATION);
 }
 
 
 void MarkCompactCollector::RecordCodeEntrySlot(Address slot, Code* target) {
   Page* target_page = Page::FromAddress(reinterpret_cast<Address>(target));
   if (target_page->IsEvacuationCandidate() &&
       !ShouldSkipEvacuationSlotRecording(reinterpret_cast<Object**>(slot))) {
     if (!SlotsBuffer::AddTo(&slots_buffer_allocator_,
                             target_page->slots_buffer_address(),
                             SlotsBuffer::CODE_ENTRY_SLOT, slot,
@@ skipping 78 matching lines @@
   SlotsBuffer* buffer = *buffer_address;
   while (buffer != NULL) {
     SlotsBuffer* next_buffer = buffer->next();
     DeallocateBuffer(buffer);
     buffer = next_buffer;
   }
   *buffer_address = NULL;
 }
 }
 }  // namespace v8::internal