Port number string cache lookup for heap numbers in generatred code.

src/x64/codegen-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 921 matching lines @@
   // the label not_found with only the content of register object unchanged.
   static void GenerateLookupNumberStringCache(MacroAssembler* masm,
                                               Register object,
                                               Register result,
                                               Register scratch1,
                                               Register scratch2,
                                               bool object_is_smi,
                                               Label* not_found);
 
  private:
+  static void GenerateConvertHashCodeToIndex(MacroAssembler* masm,
+                                             Register hash,
+                                             Register mask);
+
   Major MajorKey() { return NumberToString; }
   int MinorKey() { return 0; }
 
   void Generate(MacroAssembler* masm);
 
   const char* GetName() { return "NumberToStringStub"; }
 
 #ifdef DEBUG
   void Print() {
     PrintF("NumberToStringStub\n");
   }
 #endif
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODEGEN_X64_H_