[turbofan] Make ContextScope a proper encapsulation of the current context.

src/compiler/ast-graph-builder.h

 // Copyright 2014 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.
 
 #ifndef V8_COMPILER_AST_GRAPH_BUILDER_H_
 #define V8_COMPILER_AST_GRAPH_BUILDER_H_
 
 #include "src/v8.h"
 
 #include "src/ast.h"
@@ skipping 80 matching lines @@
   SetOncePointer<Node> function_closure_;
   SetOncePointer<Node> function_context_;
 
   // Temporary storage for building node input lists.
   int input_buffer_size_;
   Node** input_buffer_;
 
   // Node representing the control dependency for dead code.
   SetOncePointer<Node> dead_control_;
 
-  // Node representing the current context within the function body.
-  Node* current_context_;
-
   // Merge of all control nodes that exit the function body.
   Node* exit_control_;
 
   // Result of loop assignment analysis performed before graph creation.
   LoopAssignmentAnalysis* loop_assignment_analysis_;
 
   // Growth increment for the temporary buffer used to construct input lists to
   // new nodes.
   static const int kInputBufferSizeIncrement = 64;
 
   Zone* local_zone() const { return local_zone_; }
   Environment* environment() { return environment_; }
   AstContext* ast_context() const { return ast_context_; }
   ControlScope* execution_control() const { return execution_control_; }
   ContextScope* execution_context() const { return execution_context_; }
   CommonOperatorBuilder* common() const { return jsgraph_->common(); }
   CompilationInfo* info() const { return info_; }
   StrictMode strict_mode() const;
   JSGraph* jsgraph() { return jsgraph_; }
   Graph* graph() { return jsgraph_->graph(); }
   Zone* graph_zone() { return graph()->zone(); }
   JSOperatorBuilder* javascript() { return jsgraph_->javascript(); }
   ZoneVector<Handle<Object>>* globals() { return &globals_; }
   Scope* current_scope() const;
-  Node* current_context() const { return current_context_; }
+  Node* current_context() const;
   Node* dead_control();
   Node* exit_control() const { return exit_control_; }
 
   void set_environment(Environment* env) { environment_ = env; }
   void set_ast_context(AstContext* ctx) { ast_context_ = ctx; }
   void set_execution_control(ControlScope* ctrl) { execution_control_ = ctrl; }
   void set_execution_context(ContextScope* ctx) { execution_context_ = ctx; }
-  void set_current_context(Node* ctx) { current_context_ = ctx; }
   void set_exit_control(Node* exit) { exit_control_ = exit; }
 
   // Node creation helpers.
   Node* NewNode(const Operator* op, bool incomplete = false) {
     return MakeNode(op, 0, static_cast<Node**>(NULL), incomplete);
   }
 
   Node* NewNode(const Operator* op, Node* n1) {
     return MakeNode(op, 1, &n1, false);
   }
@@ skipping 308 matching lines @@
 
   // Prepare environment to be used as loop header.
   void PrepareForLoop(BitVector* assigned, bool is_osr = false);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_AST_GRAPH_BUILDER_H_