X64: Reenabled RSet.

src/spaces-inl.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 85 matching lines @@
   // This method can be called in all rset states.
   memset(RSetStart(), 0, kRSetEndOffset - kRSetStartOffset);
 }
 
 
 // Given a 32-bit address, separate its bits into:
 // | page address | words (6) | bit offset (5) | pointer alignment (2) |
 // The address of the rset word containing the bit for this word is computed as:
 //    page_address + words * 4
 // For a 64-bit address, if it is:
-// | page address | quadwords(5) | bit offset(5) | pointer alignment (3) |
+// | page address | words(5) | bit offset(5) | pointer alignment (3) |
 // The address of the rset word containing the bit for this word is computed as:
-//    page_address + quadwords * 4 + kRSetOffset.
+//    page_address + words * 4 + kRSetOffset.
 // The rset is accessed as 32-bit words, and bit offsets in a 32-bit word,
 // even on the X64 architecture.
 
 Address Page::ComputeRSetBitPosition(Address address, int offset,
                                      uint32_t* bitmask) {
   ASSERT(Page::is_rset_in_use());
 
   Page* page = Page::FromAddress(address);
   uint32_t bit_offset = ArithmeticShiftRight(page->Offset(address) + offset,
-                                             kObjectAlignmentBits);
+                                             kPointerSizeLog2);
   *bitmask = 1 << (bit_offset % kBitsPerInt);
 
   Address rset_address =
       page->address() + kRSetOffset + (bit_offset / kBitsPerInt) * kIntSize;
   // The remembered set address is either in the normal remembered set range
   // of a page or else we have a large object page.
   ASSERT((page->RSetStart() <= rset_address && rset_address < page->RSetEnd())
          || page->IsLargeObjectPage());
 
   if (rset_address >= page->RSetEnd()) {
@@ skipping 228 matching lines @@
   ASSERT(space->low() <= alloc_info->top
          && alloc_info->top <= space->high()
          && alloc_info->limit == space->high());
 #endif
   return obj;
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_INL_H_