Fix for a possible bug in RegExp stack guard.

src/x64/regexp-macro-assembler-x64.cc

 // Copyright 2011 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 1167 matching lines @@
   // Current string.
   bool is_ascii = subject->IsAsciiRepresentationUnderneath();
 
   ASSERT(re_code->instruction_start() <= *return_address);
   ASSERT(*return_address <=
       re_code->instruction_start() + re_code->instruction_size());
 
   MaybeObject* result = Execution::HandleStackGuardInterrupt();
 
   if (*code_handle != re_code) {  // Return address no longer valid
-    intptr_t delta = *code_handle - re_code;
+    intptr_t delta = code_handle->address() - re_code->address();
     // Overwrite the return address on the stack.
     *return_address += delta;
   }
 
   if (result->IsException()) {
     return EXCEPTION;
   }
 
   Handle<String> subject_tmp = subject;
   int slice_offset = 0;
@@ skipping 202 matching lines @@
   }
 }
 
 #undef __
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64