[turbofan] Context specialization is the job of the JSContextSpecialization.

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index 89373a37bca255dfad94d1bb0d2eae11685375d9..723a14b3ef8e45416edd81a9dec0d6ac93d1afc3 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -483,31 +483,18 @@ Node* AstGraphBuilder::GetFunctionClosure() {
 }
 
 
-void AstGraphBuilder::CreateFunctionContext(bool constant_context) {
-  function_context_.set(constant_context
-                            ? jsgraph()->HeapConstant(info()->context())
-                            : NewOuterContextParam());
-}
-
-
-Node* AstGraphBuilder::NewOuterContextParam() {
-  // Parameter (arity + 1) is special for the outer context of the function
-  const Operator* op =
-      common()->Parameter(info()->num_parameters_including_this(), "%context");
-  return NewNode(op, graph()->start());
-}
-
-
-Node* AstGraphBuilder::NewCurrentContextOsrValue() {
-  // TODO(titzer): use a real OSR value here; a parameter works by accident.
-  // Parameter (arity + 1) is special for the outer context of the function
-  const Operator* op = common()->Parameter(
-      info()->num_parameters_including_this(), "%osr-context");
-  return NewNode(op, graph()->start());
+Node* AstGraphBuilder::GetFunctionContext() {
+  if (!function_context_.is_set()) {
+    const Operator* op = common()->Parameter(
+        info()->num_parameters_including_this(), "%context");
+    Node* node = NewNode(op, graph()->start());
+    function_context_.set(node);
+  }
+  return function_context_.get();
 }
 
 
-bool AstGraphBuilder::CreateGraph(bool constant_context, bool stack_check) {
+bool AstGraphBuilder::CreateGraph(bool stack_check) {
   Scope* scope = info()->scope();
   DCHECK(graph() != NULL);
 
@@ -526,8 +513,7 @@ bool AstGraphBuilder::CreateGraph(bool constant_context, bool stack_check) {
   }
 
   // Initialize the incoming context.
-  CreateFunctionContext(constant_context);
-  ContextScope incoming(this, scope, function_context_.get());
+  ContextScope incoming(this, scope, GetFunctionContext());
 
   // Initialize control scope.
   ControlScope control(this);
@@ -547,7 +533,7 @@ bool AstGraphBuilder::CreateGraph(bool constant_context, bool stack_check) {
   if (info()->num_heap_slots() > 0) {
     // Push a new inner context scope for the function.
     Node* inner_context =
-        BuildLocalFunctionContext(function_context_.get(), patched_receiver);
+        BuildLocalFunctionContext(GetFunctionContext(), patched_receiver);
     ContextScope top_context(this, scope, inner_context);
     CreateGraphBody(stack_check);
   } else {
@@ -3630,7 +3616,7 @@ Node* AstGraphBuilder::BuildLoadBuiltinsObject() {
 Node* AstGraphBuilder::BuildLoadGlobalObject() {
   const Operator* load_op =
       javascript()->LoadContext(0, Context::GLOBAL_OBJECT_INDEX, true);
-  return NewNode(load_op, function_context_.get());
+  return NewNode(load_op, GetFunctionContext());
 }
 
 
@@ -4091,7 +4077,7 @@ void AstGraphBuilder::Environment::PrepareForLoop(BitVector* assigned,
     for (int i = last; i >= 0; i--) {
       Node* val = contexts()->at(i);
       if (!IrOpcode::IsConstantOpcode(val->opcode())) {
-        osr_context = (i == last) ? builder_->NewCurrentContextOsrValue()
+        osr_context = (i == last) ? builder_->GetFunctionContext()
                                   : graph->NewNode(op, osr_context, osr_context,
                                                    osr_loop_entry);
         contexts()->at(i) = builder_->MergeValue(val, osr_context, control);