[turbofan] First steps towards optimizing for-in loops.

src/compiler/js-graph.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/code-stubs.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/typer.h"
 
 namespace v8 {
@@ skipping 165 matching lines @@
 
 Node* JSGraph::ExternalConstant(ExternalReference reference) {
   Node** loc = cache_.FindExternalConstant(reference);
   if (*loc == NULL) {
     *loc = graph()->NewNode(common()->ExternalConstant(reference));
   }
   return *loc;
 }
 
 
+Node* JSGraph::ExternalConstant(Runtime::FunctionId function_id) {
+  return ExternalConstant(ExternalReference(function_id, isolate()));
+}
+
+
 Node* JSGraph::EmptyFrameState() {
   Node* empty_frame_state = cached_nodes_[kEmptyFrameState];
   if (!empty_frame_state || empty_frame_state->IsDead()) {
     Node* state_values = graph()->NewNode(common()->StateValues(0));
     empty_frame_state = graph()->NewNode(
         common()->FrameState(JS_FRAME, BailoutId::None(),
                              OutputFrameStateCombine::Ignore()),
         state_values, state_values, state_values, NoContextConstant(),
         UndefinedConstant(), graph()->start());
     cached_nodes_[kEmptyFrameState] = empty_frame_state;
@@ skipping 12 matching lines @@
   for (size_t i = 0; i < arraysize(cached_nodes_); i++) {
     if (Node* node = cached_nodes_[i]) {
       if (!node->IsDead()) nodes->push_back(node);
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8