Allow monomorphic loads when static type is known.

src/hydrogen-instructions.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 752 matching lines @@
 
   // Printing support.
   virtual void PrintTo(StringStream* stream) = 0;
   void PrintNameTo(StringStream* stream);
   void PrintTypeTo(StringStream* stream);
   void PrintRangeTo(StringStream* stream);
   void PrintChangesTo(StringStream* stream);
 
   const char* Mnemonic() const;
 
+  // Type information helpers.
+  bool HasMonomorphicJSObjectType();
+
+  // TODO(mstarzinger): For now instructions can override this function to
+  // specify statically known types, once HType can convey more information
+  // it should be based on the HType.
+  virtual Handle<Map> GetMonomorphicJSObjectMap() { return Handle<Map>(); }
+
   // Updated the inferred type of this instruction and returns true if
   // it has changed.
   bool UpdateInferredType();
 
   virtual HType CalculateInferredType();
 
   // This function must be overridden for instructions which have the
   // kTrackSideEffectDominators flag set, to track instructions that are
   // dominating side effects.
   virtual void SetSideEffectDominator(GVNFlag side_effect, HValue* dominator) {
@@ skipping 4229 matching lines @@
 
   // Maximum instance size for which allocations will be inlined.
   static const int kMaxSize = 64 * kPointerSize;
 
   HValue* context() { return OperandAt(0); }
   Handle<JSFunction> constructor() { return constructor_; }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
+  virtual Handle<Map> GetMonomorphicJSObjectMap() {
+    ASSERT(constructor()->has_initial_map());
+    return Handle<Map>(constructor()->initial_map());
+  }
   virtual HType CalculateInferredType();
 
   DECLARE_CONCRETE_INSTRUCTION(AllocateObject)
 
  private:
   // TODO(svenpanne) Might be safe, but leave it out until we know for sure.
   //  virtual bool IsDeletable() const { return true; }
 
   Handle<JSFunction> constructor_;
 };
@@ skipping 47 matching lines @@
   // graphs to be considered for fast deep-copying.
   static const int kMaxLiteralDepth = 3;
   static const int kMaxLiteralProperties = 8;
 
   HValue* context() { return OperandAt(0); }
   Handle<JSObject> boilerplate() const { return boilerplate_; }
   int total_size() const { return total_size_; }
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
+  virtual Handle<Map> GetMonomorphicJSObjectMap() {
+    return Handle<Map>(boilerplate()->map());
+  }
   virtual HType CalculateInferredType();
 
   DECLARE_CONCRETE_INSTRUCTION(FastLiteral)
 
  private:
   Handle<JSObject> boilerplate_;
   int total_size_;
 };
 
 
@@ skipping 425 matching lines @@
   virtual bool IsDeletable() const { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_