Simple support for const variables in Crankshaft....

src/hydrogen-instructions.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 111 matching lines @@
 //       HArrayLength
 //       HBitNot
 //       HChange
 //       HCheckFunction
 //       HCheckInstanceType
 //       HCheckMap
 //       HCheckNonSmi
 //       HCheckPrototypeMaps
 //       HCheckSmi
 //       HDeleteProperty
+//       HInitConst
 //       HLoadElements
 //         HTypeofIs
 //       HLoadNamedField
 //       HPushArgument
 //       HTypeof
 //       HUnaryMathOperation
 //       HUnaryPredicate
 //         HClassOfTest
 //         HHasCachedArrayIndex
 //         HHasInstanceType
@@ skipping 58 matching lines @@
   V(CompareMapAndBranch)                       \
   V(Constant)                                  \
   V(DeleteProperty)                            \
   V(Deoptimize)                                \
   V(Div)                                       \
   V(EnterInlined)                              \
   V(FunctionLiteral)                           \
   V(GlobalObject)                              \
   V(GlobalReceiver)                            \
   V(Goto)                                      \
+  V(InitConst)                                 \
   V(InstanceOf)                                \
   V(IsNull)                                    \
   V(IsObject)                                  \
   V(IsSmi)                                     \
   V(HasInstanceType)                           \
   V(HasCachedArrayIndex)                       \
   V(ClassOfTest)                               \
   V(LeaveInlined)                              \
   V(LoadElements)                              \
   V(LoadGlobal)                                \
@@ skipping 734 matching lines @@
  protected:
   virtual void InternalSetOperandAt(int index, HValue* value) {
     operands_[index] = value;
   }
 
  private:
   HOperandVector<1> operands_;
 };
 
 
+class HInitConst: public HUnaryOperation {
+ public:
+  explicit HInitConst(HValue* old_value) : HUnaryOperation(old_value) { }
+  DECLARE_CONCRETE_INSTRUCTION(InitConst, "init_const")
+};
+
+
 class HChange: public HUnaryOperation {
  public:
   HChange(HValue* value,
           Representation from,
           Representation to)
       : HUnaryOperation(value), from_(from), to_(to) {
     ASSERT(!from.IsNone() && !to.IsNone());
     ASSERT(!from.Equals(to));
     set_representation(to);
     SetFlag(kUseGVN);
@@ skipping 1966 matching lines @@
   HValue* object() const { return left(); }
   HValue* key() const { return right(); }
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_