Support StringLength in hydrogen (similar to ArrayLength).

src/ast.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 1187 matching lines @@
   // Synthetic properties are property lookups introduced by the system,
   // to objects that aren't visible to the user. Function calls to synthetic
   // properties should use the global object as receiver, not the base object
   // of the resolved Reference.
   enum Type { NORMAL, SYNTHETIC };
   Property(Expression* obj, Expression* key, int pos, Type type = NORMAL)
       : obj_(obj),
         key_(key),
         pos_(pos),
         type_(type),
+        receiver_types_(NULL),
         is_monomorphic_(false),
-        receiver_types_(NULL),
         is_array_length_(false),
+        is_string_length_(false),
         is_function_prototype_(false),
         is_arguments_access_(false) { }
 
   DECLARE_NODE_TYPE(Property)
 
   virtual bool IsValidLeftHandSide() { return true; }
   virtual bool IsInlineable() const;
 
   Expression* obj() const { return obj_; }
   Expression* key() const { return key_; }
   int position() const { return pos_; }
   bool is_synthetic() const { return type_ == SYNTHETIC; }
 
+  bool IsStringLength() const { return is_string_length_; }
   bool IsFunctionPrototype() const { return is_function_prototype_; }
 
   // Marks that this is actually an argument rewritten to a keyed property
   // accessing the argument through the arguments shadow object.
   void set_is_arguments_access(bool is_arguments_access) {
     is_arguments_access_ = is_arguments_access;
   }
   bool is_arguments_access() const { return is_arguments_access_; }
 
   // Type feedback information.
   void RecordTypeFeedback(TypeFeedbackOracle* oracle);
   virtual bool IsMonomorphic() { return is_monomorphic_; }
   virtual ZoneMapList* GetReceiverTypes() { return receiver_types_; }
   virtual bool IsArrayLength() { return is_array_length_; }
   virtual Handle<Map> GetMonomorphicReceiverType() {
     return monomorphic_receiver_type_;
   }
 
   // Returns a property singleton property access on 'this'.  Used
   // during preparsing.
   static Property* this_property() { return &this_property_; }
 
  private:
   Expression* obj_;
   Expression* key_;
   int pos_;
   Type type_;
 
-  bool is_monomorphic_;
   ZoneMapList* receiver_types_;
-  bool is_array_length_;
-  bool is_function_prototype_;
-  bool is_arguments_access_;
+  bool is_monomorphic_ : 1;
+  bool is_array_length_ : 1;
+  bool is_string_length_ : 1;
+  bool is_function_prototype_ : 1;
+  bool is_arguments_access_ : 1;
   Handle<Map> monomorphic_receiver_type_;
 
   // Dummy property used during preparsing.
   static Property this_property_;
 };
 
 
 class Call: public Expression {
  public:
   Call(Expression* expression, ZoneList<Expression*>* arguments, int pos)
@@ skipping 903 matching lines @@
   AST_NODE_LIST(DEF_VISIT)
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_