[Interpreter] Always store current context in the frames context slot.

src/compiler/bytecode-graph-builder.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/bytecode-graph-builder.h"
 
 #include "src/compiler/bytecode-branch-analysis.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/operator-properties.h"
 #include "src/interpreter/bytecodes.h"
@@ skipping 137 matching lines @@
 }
 
 
 Node* BytecodeGraphBuilder::Environment::LookupAccumulator() const {
   return values()->at(accumulator_base_);
 }
 
 
 Node* BytecodeGraphBuilder::Environment::LookupRegister(
     interpreter::Register the_register) const {
-  if (the_register.is_function_context()) {
-    return builder()->GetFunctionContext();
+  if (the_register.is_current_context()) {
+    return Context();
   } else if (the_register.is_function_closure()) {
     return builder()->GetFunctionClosure();
   } else if (the_register.is_new_target()) {
     return builder()->GetNewTarget();
   } else {
     int values_index = RegisterToValuesIndex(the_register);
     return values()->at(values_index);
   }
 }
 
@@ skipping 857 matching lines @@
 
 void BytecodeGraphBuilder::VisitKeyedStoreICStrictWide(
     const interpreter::BytecodeArrayIterator& iterator) {
   DCHECK(is_strict(language_mode()));
   BuildKeyedStore(iterator);
 }
 
 
 void BytecodeGraphBuilder::VisitPushContext(
     const interpreter::BytecodeArrayIterator& iterator) {
-  Node* context = environment()->LookupAccumulator();
-  environment()->BindRegister(iterator.GetRegisterOperand(0), context);
-  environment()->SetContext(context);
+  Node* new_context = environment()->LookupAccumulator();
+  environment()->BindRegister(iterator.GetRegisterOperand(0),
+                              environment()->Context());
+  environment()->SetContext(new_context);
 }
 
 
 void BytecodeGraphBuilder::VisitPopContext(
     const interpreter::BytecodeArrayIterator& iterator) {
   Node* context = environment()->LookupRegister(iterator.GetRegisterOperand(0));
   environment()->SetContext(context);
 }
 
 
@@ skipping 1050 matching lines @@
 
 void BytecodeGraphBuilder::UpdateControlDependencyToLeaveFunction(Node* exit) {
   if (environment()->IsMarkedAsUnreachable()) return;
   environment()->MarkAsUnreachable();
   exit_controls_.push_back(exit);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8