Fix/implement new write barrier for x64.

src/x64/code-stubs-x64.h

 // Copyright 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 45 matching lines @@
   ToBooleanStub() { }
 
   void Generate(MacroAssembler* masm);
 
  private:
   Major MajorKey() { return ToBoolean; }
   int MinorKey() { return 0; }
 };
 
 
+class WriteBufferOverflowStub: public CodeStub {
+ public:
+  explicit WriteBufferOverflowStub(SaveFPRegsMode save_fp)
+      : save_doubles_(save_fp) { }
+
+  void Generate(MacroAssembler* masm);
+
+ private:
+  SaveFPRegsMode save_doubles_;
+
+  Major MajorKey() { return WriteBufferOverflow; }
+  int MinorKey() { return (save_doubles_ == kSaveFPRegs) ? 1 : 0; }
+};
+
+
 // Flag that indicates how to generate code for the stub GenericBinaryOpStub.
 enum GenericBinaryFlags {
   NO_GENERIC_BINARY_FLAGS = 0,
   NO_SMI_CODE_IN_STUB = 1 << 0  // Omit smi code in stub.
 };
 
 
 class GenericBinaryOpStub: public CodeStub {
  public:
   GenericBinaryOpStub(Token::Value op,
@@ skipping 268 matching lines @@
   void Print() {
     PrintF("NumberToStringStub\n");
   }
 #endif
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODE_STUBS_X64_H_