ES6 symbols: Implement Symbol intrinsic and basic functionality

src/code-stubs.h

 // Copyright 2012 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 770 matching lines @@
                              CompareIC::State* right_state,
                              CompareIC::State* handler_state,
                              Token::Value* op);
 
   static CompareIC::State CompareState(int minor_key) {
     return static_cast<CompareIC::State>(HandlerStateField::decode(minor_key));
   }
 
  private:
   class OpField: public BitField<int, 0, 3> { };
-  class LeftStateField: public BitField<int, 3, 3> { };
-  class RightStateField: public BitField<int, 6, 3> { };
-  class HandlerStateField: public BitField<int, 9, 3> { };
+  class LeftStateField: public BitField<int, 3, 4> { };
+  class RightStateField: public BitField<int, 7, 4> { };
+  class HandlerStateField: public BitField<int, 11, 4> { };
 
   virtual void FinishCode(Handle<Code> code) {
     code->set_stub_info(MinorKey());
   }
 
   virtual CodeStub::Major MajorKey() { return CompareIC; }
   virtual int MinorKey();
 
   virtual int GetCodeKind() { return Code::COMPARE_IC; }
 
   void GenerateSmis(MacroAssembler* masm);
   void GenerateHeapNumbers(MacroAssembler* masm);
   void GenerateInternalizedStrings(MacroAssembler* masm);
   void GenerateStrings(MacroAssembler* masm);
+  void GenerateUniqueNames(MacroAssembler* masm);
   void GenerateObjects(MacroAssembler* masm);
   void GenerateMiss(MacroAssembler* masm);
   void GenerateKnownObjects(MacroAssembler* masm);
   void GenerateGeneric(MacroAssembler* masm);
 
   bool strict() const { return op_ == Token::EQ_STRICT; }
   Condition GetCondition() const { return CompareIC::ComputeCondition(op_); }
 
   virtual void AddToSpecialCache(Handle<Code> new_object);
   virtual bool FindCodeInSpecialCache(Code** code_out, Isolate* isolate);
@@ skipping 655 matching lines @@
 
   // The current function entry hook.
   static FunctionEntryHook entry_hook_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileEntryHookStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_