Add a generic remembered set class.

src/heap/spaces.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/atomic-utils.h"
 #include "src/base/atomicops.h"
@@ skipping 380 matching lines @@
       + kPointerSize              // Address owner_
       + kPointerSize              // Heap* heap_
       + kIntSize;                 // int progress_bar_
 
   static const size_t kSlotsBufferOffset =
       kLiveBytesOffset + kIntSize;  // int live_byte_count_
 
   static const size_t kWriteBarrierCounterOffset =
       kSlotsBufferOffset + kPointerSize  // SlotsBuffer* slots_buffer_;
       + kPointerSize                     // SlotSet* old_to_new_slots_;
+      + kPointerSize                     // SlotSet* old_to_old_slots_;
       + kPointerSize;                    // SkipList* skip_list_;
 
   static const size_t kMinHeaderSize =
       kWriteBarrierCounterOffset +
       kIntptrSize         // intptr_t write_barrier_counter_
       + kPointerSize      // AtomicValue high_water_mark_
       + kPointerSize      // base::Mutex* mutex_
       + kPointerSize      // base::AtomicWord parallel_sweeping_
       + kPointerSize      // AtomicValue parallel_compaction_
       + 5 * kPointerSize  // AtomicNumber free-list statistics
@@ skipping 27 matching lines @@
 
   static const MemoryChunk* FromAddress(const byte* a) {
     return reinterpret_cast<const MemoryChunk*>(OffsetFrom(a) &
                                                 ~kAlignmentMask);
   }
 
   static void IncrementLiveBytesFromGC(HeapObject* object, int by) {
     MemoryChunk::FromAddress(object->address())->IncrementLiveBytes(by);
   }
 
-  // Only works for addresses in pointer spaces, not data or code spaces.
+  // Only works for addresses in pointer spaces, not code space.
   static inline MemoryChunk* FromAnyPointerAddress(Heap* heap, Address addr);
 
   static inline uint32_t FastAddressToMarkbitIndex(Address addr) {
     const intptr_t offset = reinterpret_cast<intptr_t>(addr) & kAlignmentMask;
     return static_cast<uint32_t>(offset) >> kPointerSizeLog2;
   }
 
   static inline void UpdateHighWaterMark(Address mark) {
     if (mark == nullptr) return;
     // Need to subtract one from the mark because when a chunk is full the
@@ skipping 212 matching lines @@
   inline SkipList* skip_list() { return skip_list_; }
 
   inline void set_skip_list(SkipList* skip_list) { skip_list_ = skip_list; }
 
   inline SlotsBuffer* slots_buffer() { return slots_buffer_; }
 
   inline SlotsBuffer** slots_buffer_address() { return &slots_buffer_; }
 
   inline SlotSet* old_to_new_slots() { return old_to_new_slots_; }
 
+  inline SlotSet* old_to_old_slots() { return old_to_old_slots_; }
+
   void AllocateOldToNewSlots();
   void ReleaseOldToNewSlots();
+  void AllocateOldToOldSlots();
+  void ReleaseOldToOldSlots();
 
   void MarkEvacuationCandidate() {
     DCHECK(!IsFlagSet(NEVER_EVACUATE));
     DCHECK(slots_buffer_ == NULL);
     SetFlag(EVACUATION_CANDIDATE);
   }
 
   void ClearEvacuationCandidate() {
     DCHECK(slots_buffer_ == NULL);
     ClearFlag(EVACUATION_CANDIDATE);
@@ skipping 32 matching lines @@
   // Used by the incremental marker to keep track of the scanning progress in
   // large objects that have a progress bar and are scanned in increments.
   int progress_bar_;
   // Count of bytes marked black on page.
   int live_byte_count_;
   SlotsBuffer* slots_buffer_;
   // A single slot set for small pages (of size kPageSize) or an array of slot
   // set for large pages. In the latter case the number of entries in the array
   // is ceil(size() / kPageSize).
   SlotSet* old_to_new_slots_;
+  SlotSet* old_to_old_slots_;
   SkipList* skip_list_;
   intptr_t write_barrier_counter_;
   // Assuming the initial allocation on a page is sequential,
   // count highest number of bytes ever allocated on the page.
   AtomicValue<intptr_t> high_water_mark_;
 
   base::Mutex* mutex_;
   AtomicValue<ConcurrentSweepingState> concurrent_sweeping_;
   AtomicValue<ParallelCompactingState> parallel_compaction_;
 
@@ skipping 29 matching lines @@
 class Page : public MemoryChunk {
  public:
   // Returns the page containing a given address. The address ranges
   // from [page_addr .. page_addr + kPageSize[
   // This only works if the object is in fact in a page.  See also MemoryChunk::
   // FromAddress() and FromAnyAddress().
   INLINE(static Page* FromAddress(Address a)) {
     return reinterpret_cast<Page*>(OffsetFrom(a) & ~kPageAlignmentMask);
   }
 
+  // Only works for addresses in pointer spaces, not code space.
+  inline static Page* FromAnyPointerAddress(Heap* heap, Address addr);
+
   // Returns the page containing an allocation top. Because an allocation
   // top address can be the upper bound of the page, we need to subtract
   // it with kPointerSize first. The address ranges from
   // [page_addr + kObjectStartOffset .. page_addr + kPageSize].
   INLINE(static Page* FromAllocationTop(Address top)) {
     Page* p = FromAddress(top - kPointerSize);
     return p;
   }
 
   // Returns the next page in the chain of pages owned by a space.
@@ skipping 2268 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_SPACES_H_