[turbofan] Introduce JSStackCheck operator.

src/compiler/js-generic-lowering.h

 // 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.
 
 #ifndef V8_COMPILER_JS_GENERIC_LOWERING_H_
 #define V8_COMPILER_JS_GENERIC_LOWERING_H_
 
 #include "src/allocation.h"
 #include "src/code-factory.h"
 #include "src/compiler/graph.h"
@@ skipping 33 matching lines @@
   void ReplaceWithRuntimeCall(Node* node, Runtime::FunctionId f, int args = -1);
 
   // Helper for optimization of JSCallFunction.
   bool TryLowerDirectJSCall(Node* node);
 
   Zone* zone() const { return graph()->zone(); }
   Isolate* isolate() const { return jsgraph()->isolate(); }
   JSGraph* jsgraph() const { return jsgraph_; }
   Graph* graph() const { return jsgraph()->graph(); }
   CommonOperatorBuilder* common() const { return jsgraph()->common(); }
+  JSOperatorBuilder* javascript() const { return jsgraph()->javascript(); }

[Michael Starzinger, 2015/03/06 14:06:39]

Is this used anywhere? If it is then that's actually a problem, because that
means that generic lowering leaves JS nodes around. Let's drop it again.

[Benedikt Meurer, 2015/03/09 05:01:45]

That was leftover from a previous attempt. Removed.

   MachineOperatorBuilder* machine() const { return jsgraph()->machine(); }
 
  private:
   bool is_typing_enabled_;
-  JSGraph* jsgraph_;
+  JSGraph* const jsgraph_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_JS_GENERIC_LOWERING_H_