Replace ChainContextInstr with existing IL instructions.

runtime/vm/intermediate_language_x64.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 4352 matching lines @@
 
   Label done;
   __ LoadObject(result, Bool::True());
   __ CompareRegisters(result, value);
   __ j(NOT_EQUAL, &done, Assembler::kNearJump);
   __ LoadObject(result, Bool::False());
   __ Bind(&done);
 }
 
 
-LocationSummary* ChainContextInstr::MakeLocationSummary() const {
-  return LocationSummary::Make(1,
-                               Location::NoLocation(),
-                               LocationSummary::kNoCall);
-}
-
-
-void ChainContextInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  Register context_value = locs()->in(0).reg();
-
-  // Chain the new context in context_value to its parent in CTX.
-  __ StoreIntoObject(context_value,
-                     FieldAddress(context_value, Context::parent_offset()),
-                     CTX);
-  // Set new context as current context.
-  __ MoveRegister(CTX, context_value);
-}
-
-
 LocationSummary* StoreVMFieldInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 2;
   const intptr_t kNumTemps = 0;
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_in(0, value()->NeedsStoreBuffer() ? Location::WritableRegister()
                                               : Location::RequiresRegister());
   locs->set_in(1, Location::RequiresRegister());
   return locs;
 }
@@ skipping 46 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64