[turbofan] Initial version of allocation folding and write barrier elimination.

src/compiler/js-generic-lowering.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-factory.h"
 #include "src/code-stubs.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/js-generic-lowering.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 120 matching lines @@
 void JSGenericLowering::LowerJSStrictNotEqual(Node* node) {
   Callable callable = CodeFactory::StrictNotEqual(isolate());
   node->AppendInput(zone(), graph()->start());
   ReplaceWithStubCall(node, callable, CallDescriptor::kNoFlags,
                       Operator::kEliminatable);
 }
 
 void JSGenericLowering::LowerJSToBoolean(Node* node) {
   Callable callable = CodeFactory::ToBoolean(isolate());
   node->AppendInput(zone(), graph()->start());
-  ReplaceWithStubCall(node, callable, CallDescriptor::kNoFlags,
+  ReplaceWithStubCall(node, callable, CallDescriptor::kNoAllocate,
                       Operator::kEliminatable);
 }
 
 void JSGenericLowering::LowerJSTypeOf(Node* node) {
   Callable callable = CodeFactory::Typeof(isolate());
   node->AppendInput(zone(), graph()->start());
-  ReplaceWithStubCall(node, callable, CallDescriptor::kNoFlags,
+  ReplaceWithStubCall(node, callable, CallDescriptor::kNoAllocate,
                       Operator::kEliminatable);
 }
 
 
 void JSGenericLowering::LowerJSLoadProperty(Node* node) {
   Node* closure = NodeProperties::GetValueInput(node, 2);
   Node* effect = NodeProperties::GetEffectInput(node);
   Node* control = NodeProperties::GetControlInput(node);
   CallDescriptor::Flags flags = AdjustFrameStatesForCall(node);
   const PropertyAccess& p = PropertyAccessOf(node->op());
@@ skipping 581 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSGenericLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8