ES6 symbols: Implement Symbol intrinsic and basic functionality

src/ic.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 740 matching lines @@
 
 
 class CompareIC: public IC {
  public:
   enum State {
     UNINITIALIZED,
     SMI,
     HEAP_NUMBER,
     STRING,
     INTERNALIZED_STRING,
+    UNIQUE_NAME,    // Symbol or InternalizedString
     OBJECT,
     KNOWN_OBJECTS,
     GENERIC
   };
 
   CompareIC(Isolate* isolate, Token::Value op)
       : IC(EXTRA_CALL_FRAME, isolate), op_(op) { }
 
   // Update the inline cache for the given operands.
   void UpdateCaches(Handle<Object> x, Handle<Object> y);
@@ skipping 41 matching lines @@
 // Helper for BinaryOpIC and CompareIC.
 enum InlinedSmiCheck { ENABLE_INLINED_SMI_CHECK, DISABLE_INLINED_SMI_CHECK };
 void PatchInlinedSmiCode(Address address, InlinedSmiCheck check);
 
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedLoadIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedLoadIC_MissFromStubFailure);
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_H_