[turbofan] Specialize loads of the native context.

src/compiler/node-properties.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/common-operator.h"
 #include "src/compiler/graph.h"
+#include "src/compiler/js-operator.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
 #include "src/compiler/verifier.h"
 #include "src/handles-inl.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
@@ skipping 311 matching lines @@
   }
   return MaybeHandle<Context>();
 }
 
 
 // static
 MaybeHandle<Context> NodeProperties::GetSpecializationNativeContext(
     Node* node, MaybeHandle<Context> native_context) {
   while (true) {
     switch (node->opcode()) {
+      case IrOpcode::kJSLoadContext: {
+        ContextAccess const& access = ContextAccessOf(node->op());
+        if (access.index() != Context::NATIVE_CONTEXT_INDEX) {
+          return MaybeHandle<Context>();
+        }
+        // Skip over the intermediate contexts, we're only interested in the
+        // very last context in the context chain anyway.
+        node = NodeProperties::GetContextInput(node);
+        break;
+      }
       case IrOpcode::kJSCreateBlockContext:
       case IrOpcode::kJSCreateCatchContext:
       case IrOpcode::kJSCreateFunctionContext:
       case IrOpcode::kJSCreateModuleContext:
       case IrOpcode::kJSCreateScriptContext:
       case IrOpcode::kJSCreateWithContext: {
         // Skip over the intermediate contexts, we're only interested in the
         // very last context in the context chain anyway.
         node = NodeProperties::GetContextInput(node);
         break;
@@ skipping 60 matching lines @@
 // static
 bool NodeProperties::IsInputRange(Edge edge, int first, int num) {
   if (num == 0) return false;
   int const index = edge.index();
   return first <= index && index < first + num;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8