Merge fix for incorrect overlap check in mark compact collector to 3.2

src/heap-inl.h

 // Copyright 2006-2010 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 349 matching lines @@
 
   page->SetRegionMarks(marks);
 }
 
 
 void Heap::MoveBlock(Address dst, Address src, int byte_size) {
   ASSERT(IsAligned(byte_size, kPointerSize));
 
   int size_in_words = byte_size / kPointerSize;
 
-  if ((dst < src) || (dst >= (src + size_in_words))) {
-    ASSERT((dst >= (src + size_in_words)) ||
-           ((OffsetFrom(reinterpret_cast<Address>(src)) -
-             OffsetFrom(reinterpret_cast<Address>(dst))) >= kPointerSize));
-
+  if ((dst < src) || (dst >= (src + byte_size))) {
     Object** src_slot = reinterpret_cast<Object**>(src);
     Object** dst_slot = reinterpret_cast<Object**>(dst);
     Object** end_slot = src_slot + size_in_words;
 
     while (src_slot != end_slot) {
       *dst_slot++ = *src_slot++;
     }
   } else {
     memmove(dst, src, byte_size);
   }
 }
 
 
 void Heap::MoveBlockToOldSpaceAndUpdateRegionMarks(Address dst,
                                                    Address src,
                                                    int byte_size) {
   ASSERT(IsAligned(byte_size, kPointerSize));
-  ASSERT((dst >= (src + byte_size)) ||
-         ((OffsetFrom(src) - OffsetFrom(dst)) >= kPointerSize));
+  ASSERT((dst < src) || (dst >= (src + byte_size)));
 
   CopyBlockToOldSpaceAndUpdateRegionMarks(dst, src, byte_size);
 }
 
 
 void Heap::ScavengePointer(HeapObject** p) {
   ScavengeObject(p, *p);
 }
 
 
@@ skipping 290 matching lines @@
 #ifdef DEBUG
   UpdateLiveObjectCount(obj);
 #endif
   obj->SetMark();
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_