Out of bounds memory access in TestJSArrayForAllocationSiteInfo.

src/x64/macro-assembler-x64.cc

 // Copyright 2012 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 4597 matching lines @@
     Register receiver_reg,
     Register scratch_reg,
     Label* allocation_info_present) {
   Label no_info_available;
   ExternalReference new_space_start =
       ExternalReference::new_space_start(isolate());
   ExternalReference new_space_allocation_top =
       ExternalReference::new_space_allocation_top_address(isolate());
 
   lea(scratch_reg, Operand(receiver_reg,
-                           JSArray::kSize + AllocationSiteInfo::kSize));
+      JSArray::kSize + AllocationSiteInfo::kSize - kHeapObjectTag));
   movq(kScratchRegister, new_space_start);
   cmpq(scratch_reg, kScratchRegister);
   j(less, &no_info_available);
   cmpq(scratch_reg, ExternalOperand(new_space_allocation_top));
-  j(greater_equal, &no_info_available);
-  CompareRoot(MemOperand(scratch_reg, 0),
+  j(greater, &no_info_available);
+  CompareRoot(MemOperand(scratch_reg, -AllocationSiteInfo::kSize),
               Heap::kAllocationSiteInfoMapRootIndex);
   j(equal, allocation_info_present);
   bind(&no_info_available);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64