Make closures optimizable by Crankshaft compiler.

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 88 matching lines @@
 //         HBranch
 //         HCompareMapAndBranch
 //         HReturn
 //         HThrow
 //     HDeoptimize
 //     HEnterInlined
 //     HFunctionLiteral
 //     HGlobalObject
 //     HGlobalReceiver
 //     HLeaveInlined
+//     HLoadContextSlot
 //     HLoadGlobal
 //     HMaterializedLiteral
 //       HArrayLiteral
 //       HObjectLiteral
 //       HRegExpLiteral
 //     HOsrEntry
 //     HParameter
 //     HSimulate
 //     HStackCheck
 //     HStoreKeyed
@@ skipping 89 matching lines @@
   V(GlobalReceiver)                            \
   V(Goto)                                      \
   V(InstanceOf)                                \
   V(IsNull)                                    \
   V(IsObject)                                  \
   V(IsSmi)                                     \
   V(HasInstanceType)                           \
   V(HasCachedArrayIndex)                       \
   V(ClassOfTest)                               \
   V(LeaveInlined)                              \
+  V(LoadContextSlot)                           \
   V(LoadElements)                              \
   V(LoadGlobal)                                \
   V(LoadKeyedFastElement)                      \
   V(LoadKeyedGeneric)                          \
   V(LoadNamedField)                            \
   V(LoadNamedGeneric)                          \
   V(Mod)                                       \
   V(Mul)                                       \
   V(ObjectLiteral)                             \
   V(OsrEntry)                                  \
@@ skipping 2282 matching lines @@
   virtual bool DataEquals(HValue* other) const {
     HStoreGlobal* b = HStoreGlobal::cast(other);
     return cell_.is_identical_to(b->cell());
   }
 
  private:
   Handle<JSGlobalPropertyCell> cell_;
 };
 
 
+class HLoadContextSlot: public HInstruction {
+ public:
+  HLoadContextSlot(int context_chain_length , int slot_index)
+      : context_chain_length_(context_chain_length), slot_index_(slot_index) {
+    set_representation(Representation::Tagged());
+    SetFlag(kUseGVN);
+    SetFlag(kDependsOnCalls);
+  }
+
+  int context_chain_length() const { return context_chain_length_; }
+  int slot_index() const { return slot_index_; }
+
+  virtual void PrintDataTo(StringStream* stream) const;
+
+  virtual intptr_t Hashcode() const {
+    return context_chain_length() * 29 + slot_index();
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(LoadContextSlot, "load_context_slot")
+
+ protected:
+  virtual bool DataEquals(HValue* other) const {
+    HLoadContextSlot* b = HLoadContextSlot::cast(other);
+    return (context_chain_length() == b->context_chain_length())
+        && (slot_index() == b->slot_index());
+  }
+
+ private:
+  int context_chain_length_;
+  int slot_index_;
+};
+
+
 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());
     SetFlag(kUseGVN);
     if (is_in_object) {
       SetFlag(kDependsOnInobjectFields);
@@ skipping 380 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_