Implement simple fast-path code for functions containing this property stores and global variables.

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 612 matching lines @@
   // called from spilled code, because they do not leave the virtual frame
   // in a spilled state.
   bool in_spilled_code_;
 
   static InlineRuntimeLUT kInlineRuntimeLUT[];
 
   friend class VirtualFrame;
   friend class JumpTarget;
   friend class Reference;
   friend class Result;
+  friend class FastCodeGenerator;
   friend class FullCodeGenerator;
   friend class FullCodeGenSyntaxChecker;
 
   friend class CodeGeneratorPatcher;  // Used in test-log-stack-tracer.cc
 
   DISALLOW_COPY_AND_ASSIGN(CodeGenerator);
 };
 
 
 // Flag that indicates how to generate code for the stub GenericBinaryOpStub.
@@ skipping 170 matching lines @@
   Major MajorKey() { return StringCompare; }
   int MinorKey() { return 0; }
 
   void Generate(MacroAssembler* masm);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_CODEGEN_X64_H_