Make AstGraphBuilder::function_context a SetOncePointer again.

src/compiler/ast-graph-builder.cc

 // 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.
 
 #include "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/linkage.h"
@@ skipping 361 matching lines @@
 AstGraphBuilder::AstGraphBuilder(Zone* local_zone, CompilationInfo* info,
                                  JSGraph* jsgraph, LoopAssignmentAnalysis* loop)
     : local_zone_(local_zone),
       info_(info),
       jsgraph_(jsgraph),
       environment_(nullptr),
       ast_context_(nullptr),
       globals_(0, local_zone),
       execution_control_(nullptr),
       execution_context_(nullptr),
-      function_context_(nullptr),
       input_buffer_size_(0),
       input_buffer_(nullptr),
       exit_control_(nullptr),
       loop_assignment_analysis_(loop) {
   InitializeAstVisitor(info->isolate(), local_zone);
 }
 
 
 Node* AstGraphBuilder::GetFunctionClosure() {
   if (!function_closure_.is_set()) {
     const Operator* op =
         common()->Parameter(Linkage::kJSFunctionCallClosureParamIndex);
     Node* node = NewNode(op, graph()->start());
     function_closure_.set(node);
   }
   return function_closure_.get();
 }
 
 
 Node* AstGraphBuilder::GetFunctionContext() {
-  DCHECK(function_context_ != nullptr);
-  return function_context_;
+  if (!function_context_.is_set()) {
+    function_context_.set(NewOuterContextParam());
+  }
+  return function_context_.get();
 }
 
 
 Node* AstGraphBuilder::NewOuterContextParam() {
   // Parameter (arity + 1) is special for the outer context of the function
   const Operator* op = common()->Parameter(info()->num_parameters() + 1);
   return NewNode(op, graph()->start());
 }
 
 
@@ skipping 20 matching lines @@
   Environment env(this, scope, graph()->start());
   set_environment(&env);
 
   if (info()->is_osr()) {
     // Use OSR normal entry as the start of the top-level environment.
     // It will be replaced with {Dead} after typing and optimizations.
     NewNode(common()->OsrNormalEntry());
   }
 
   // Initialize the incoming context.
-  function_context_ = NewOuterContextParam();
-  ContextScope incoming(this, scope, function_context_);
+  Node* outer_context = GetFunctionContext();
+  ContextScope incoming(this, scope, outer_context);
 
   // Build receiver check for sloppy mode if necessary.
   // TODO(mstarzinger/verwaest): Should this be moved back into the CallIC?
   Node* original_receiver = env.Lookup(scope->receiver());
   Node* patched_receiver = BuildPatchReceiverToGlobalProxy(original_receiver);
   env.Bind(scope->receiver(), patched_receiver);
 
   // Build function context only if there are context allocated variables.
   int heap_slots = info()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
   if (heap_slots > 0) {
     // Push a new inner context scope for the function.
     Node* closure = GetFunctionClosure();
-    Node* inner_context = BuildLocalFunctionContext(function_context_, closure);
+    Node* inner_context = BuildLocalFunctionContext(outer_context, closure);
     ContextScope top_context(this, scope, inner_context);
     CreateGraphBody();
   } else {
     // Simply use the outer function context in building the graph.
     CreateGraphBody();
   }
 
   // Finish the basic structure of the graph.
   graph()->SetEnd(graph()->NewNode(common()->End(), exit_control()));
 
@@ skipping 2733 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8