Do not waste space for the fast-case elements backing storage for ...

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 853 matching lines @@
    private:
     Literal* key_;
     Expression* value_;
     Kind kind_;
   };
 
   ObjectLiteral(Handle<FixedArray> constant_properties,
                 ZoneList<Property*>* properties,
                 int literal_index,
                 bool is_simple,
+                bool fast_elements,
                 int depth)
       : MaterializedLiteral(literal_index, is_simple, depth),
         constant_properties_(constant_properties),
-        properties_(properties) {}
+        properties_(properties),
+        fast_elements_(fast_elements) {}
 
   virtual ObjectLiteral* AsObjectLiteral() { return this; }
   virtual void Accept(AstVisitor* v);
 
   virtual bool IsLeaf() { return properties()->is_empty(); }
 
   Handle<FixedArray> constant_properties() const {
     return constant_properties_;
   }
   ZoneList<Property*>* properties() const { return properties_; }
 
+  bool fast_elements() const { return fast_elements_; }
+
  private:
   Handle<FixedArray> constant_properties_;
   ZoneList<Property*>* properties_;
+  bool fast_elements_;
 };
 
 
 // Node for capturing a regexp literal.
 class RegExpLiteral: public MaterializedLiteral {
  public:
   RegExpLiteral(Handle<String> pattern,
                 Handle<String> flags,
                 int literal_index)
       : MaterializedLiteral(literal_index, false, 1),
@@ skipping 1003 matching lines @@
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_