Make AstGraphBuilder::function_context a SetOncePointer again.

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/ast.h"
 #include "src/compiler/js-graph.h"
 
@@ skipping 70 matching lines @@
   ZoneVector<Handle<Object>> globals_;
 
   // Stack of control scopes currently entered by the visitor.
   ControlScope* execution_control_;
 
   // Stack of context objects pushed onto the chain by the visitor.
   ContextScope* execution_context_;
 
   // Nodes representing values in the activation record.
   SetOncePointer<Node> function_closure_;
-  Node* function_context_;
+  SetOncePointer<Node> function_context_;
 
   // Temporary storage for building node input lists.
   int input_buffer_size_;
   Node** input_buffer_;
 
   // 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_;
@@ skipping 65 matching lines @@
 
   Node* NewNode(const Operator* op, int value_input_count, Node** value_inputs,
                 bool incomplete = false) {
     return MakeNode(op, value_input_count, value_inputs, incomplete);
   }
 
   // Creates a new Phi node having {count} input values.
   Node* NewPhi(int count, Node* input, Node* control);
   Node* NewEffectPhi(int count, Node* input, Node* control);
 
+  // Creates new context nodes.
   Node* NewOuterContextParam();
   Node* NewCurrentContextOsrValue();
 
   // Helpers for merging control, effect or value dependencies.
   Node* MergeControl(Node* control, Node* other);
   Node* MergeEffect(Node* value, Node* other, Node* control);
   Node* MergeValue(Node* value, Node* other, Node* control);
 
   // The main node creation chokepoint. Adds context, frame state, effect,
   // and control dependencies depending on the operator.
@@ skipping 279 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_