Port inlined version of swap primitive for sorting from ia32 to x64....

src/x64/macro-assembler-x64.h

 // Copyright 2009 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 48 matching lines @@
   MacroAssembler(void* buffer, int size);
 
   void LoadRoot(Register destination, Heap::RootListIndex index);
   void CompareRoot(Register with, Heap::RootListIndex index);
   void CompareRoot(Operand with, Heap::RootListIndex index);
   void PushRoot(Heap::RootListIndex index);
 
   // ---------------------------------------------------------------------------
   // GC Support
 
+  void RecordWriteHelper(Register object,
+                         Register addr,
+                         Register scratch);
+
   // Check if object is in new space. The condition cc can be equal or
   // not_equal. If it is equal a jump will be done if the object is on new
   // space. The register scratch can be object itself, but it will be clobbered.
   void InNewSpace(Register object,
                   Register scratch,
                   Condition cc,
                   Label* branch);
 
   // Set the remembered set bit for [object+offset].
   // object is the object being stored into, value is the object being stored.
@@ skipping 770 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_MACRO_ASSEMBLER_X64_H_