Replace ChainContextInstr with existing IL instructions.

runtime/vm/intermediate_language.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 547 matching lines @@
   M(AllocateObjectWithBoundsCheck)                                             \
   M(LoadField)                                                                 \
   M(StoreVMField)                                                              \
   M(LoadUntagged)                                                              \
   M(LoadClassId)                                                               \
   M(InstantiateType)                                                           \
   M(InstantiateTypeArguments)                                                  \
   M(ExtractConstructorTypeArguments)                                           \
   M(ExtractConstructorInstantiator)                                            \
   M(AllocateContext)                                                           \
-  M(ChainContext)                                                              \
   M(CloneContext)                                                              \
   M(CatchEntry)                                                                \
   M(BinarySmiOp)                                                               \
   M(UnarySmiOp)                                                                \
   M(CheckStackOverflow)                                                        \
   M(SmiToDouble)                                                               \
   M(DoubleToInteger)                                                           \
   M(DoubleToSmi)                                                               \
   M(DoubleToDouble)                                                            \
   M(CheckClass)                                                                \
@@ skipping 3662 matching lines @@
   virtual bool MayThrow() const { return false; }
 
  private:
   const intptr_t token_pos_;
   const intptr_t num_context_variables_;
 
   DISALLOW_COPY_AND_ASSIGN(AllocateContextInstr);
 };
 
 
-class ChainContextInstr : public TemplateInstruction<1> {
- public:
-  explicit ChainContextInstr(Value* context_value) {
-    SetInputAt(0, context_value);
-  }
-
-  DECLARE_INSTRUCTION(ChainContext)
-
-  virtual intptr_t ArgumentCount() const { return 0; }
-
-  Value* context_value() const { return inputs_[0]; }
-
-  virtual bool CanDeoptimize() const { return false; }
-
-  virtual EffectSet Effects() const { return EffectSet::None(); }
-
-  virtual bool MayThrow() const { return false; }
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ChainContextInstr);
-};
-
-
 class CloneContextInstr : public TemplateDefinition<1> {
  public:
   CloneContextInstr(intptr_t token_pos, Value* context_value)
       : token_pos_(token_pos) {
     SetInputAt(0, context_value);
   }
 
   intptr_t token_pos() const { return token_pos_; }
   Value* context_value() const { return inputs_[0]; }
 
@@ skipping 2235 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_