Hydrogen support for context allocated harmony bindings.

src/hydrogen-instructions.h

 // Copyright 2011 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 3429 matching lines @@
   DECLARE_CONCRETE_INSTRUCTION(StoreGlobalGeneric)
 
  private:
   Handle<Object> name_;
   StrictModeFlag strict_mode_flag_;
 };
 
 
 class HLoadContextSlot: public HUnaryOperation {
  public:
-  HLoadContextSlot(HValue* context , int slot_index)
-      : HUnaryOperation(context), slot_index_(slot_index) {
+  HLoadContextSlot(HValue* context , Variable* var)
+      : HUnaryOperation(context), var_(var) {
+    ASSERT(var_->IsContextSlot());
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kDependsOnContextSlots);
   }
 
-  int slot_index() const { return slot_index_; }
+  int slot_index() const { return var_->index(); }
+  Variable* var() const { return var_; }
+
+  bool RequiresHoleCheck() {
+    return var_->mode() == LET || var_->mode() == CONST_HARMONY;
+  }
 
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   DECLARE_CONCRETE_INSTRUCTION(LoadContextSlot)
 
  protected:
   virtual bool DataEquals(HValue* other) {
     HLoadContextSlot* b = HLoadContextSlot::cast(other);
     return (slot_index() == b->slot_index());
   }
 
  private:
-  int slot_index_;
+  Variable* var_;
 };
 
 
 class HStoreContextSlot: public HTemplateInstruction<2> {
  public:
-  HStoreContextSlot(HValue* context, int slot_index, HValue* value)
-      : slot_index_(slot_index) {
+  // Indicates whether this store to the context is an initializing store or
+  // a proper assignment. Non-initializing assignments to harmony bindings
+  // perform a hole check.
+  enum Mode {
+    kInitialize,
+    kAssign
+  };
+
+  HStoreContextSlot(HValue* context, Variable* var, Mode mode, HValue* value)
+      : var_(var), mode_(mode) {
+    ASSERT(var->IsContextSlot());
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     SetFlag(kChangesContextSlots);
   }
 
   HValue* context() { return OperandAt(0); }
   HValue* value() { return OperandAt(1); }
-  int slot_index() const { return slot_index_; }
+  int slot_index() const { return var_->index(); }
+  Variable* var() const { return var_; }
+  Mode mode() const { return mode_; }
 
   bool NeedsWriteBarrier() {
     return StoringValueNeedsWriteBarrier(value());
   }
 
+  bool RequiresHoleCheck() {
+    return mode_ == kAssign &&
+        (var_->mode() == LET || var_->mode() == CONST_HARMONY);
+  }
+
   virtual Representation RequiredInputRepresentation(int index) {
     return Representation::Tagged();
   }
 
   virtual void PrintDataTo(StringStream* stream);
 
   DECLARE_CONCRETE_INSTRUCTION(StoreContextSlot)
 
  private:
-  int slot_index_;
+  Variable* var_;
+  Mode mode_;
 };
 
 
 class HLoadNamedField: public HUnaryOperation {
  public:
   HLoadNamedField(HValue* object, bool is_in_object, int offset)
       : HUnaryOperation(object),
         is_in_object_(is_in_object),
         offset_(offset) {
     set_representation(Representation::Tagged());
@@ skipping 914 matching lines @@
 
   DECLARE_CONCRETE_INSTRUCTION(In)
 };
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_