Faster implementation of Heap::RecordWrites.

src/spaces.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 202 matching lines @@
   // ---------------------------------------------------------------------
   // Card marking support
 
   static const uint32_t kAllRegionsCleanMarks = 0x0;
   static const uint32_t kAllRegionsDirtyMarks = 0xFFFFFFFF;
 
   inline uint32_t GetRegionMarks();
   inline void SetRegionMarks(uint32_t dirty);
 
   inline uint32_t GetRegionMaskForAddress(Address addr);
+  inline uint32_t GetRegionMaskForSpan(Address start, int length_in_bytes);
   inline int GetRegionNumberForAddress(Address addr);
 
   inline void MarkRegionDirty(Address addr);
   inline bool IsRegionDirty(Address addr);
 
   inline void ClearRegionMarks(Address start,
                                Address end,
                                bool reaches_limit);
 
   // Page size in bytes.  This must be a multiple of the OS page size.
@@ skipping 1954 matching lines @@
 
  private:
   LargeObjectChunk* current_;
   HeapObjectCallback size_func_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_H_