[turbofan] Allow deoptimization for JSToNumber operator.

src/compiler/js-graph.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_GRAPH_H_
 #define V8_COMPILER_JS_GRAPH_H_
 
 #include "src/compiler/common-node-cache.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
@@ skipping 91 matching lines @@
 
   Node* SmiConstant(int32_t immediate) {
     DCHECK(Smi::IsValid(immediate));
     return Constant(immediate);
   }
 
   // Creates a dummy Constant node, used to satisfy calling conventions of
   // stubs and runtime functions that do not require a context.
   Node* NoContextConstant() { return ZeroConstant(); }
 
+  // Creates an empty frame states for cases where we know that a function
+  // cannot deopt.
+  Node* EmptyFrameState();
+
   JSOperatorBuilder* javascript() { return javascript_; }
   CommonOperatorBuilder* common() { return common_; }
   MachineOperatorBuilder* machine() { return machine_; }
   Graph* graph() { return graph_; }
   Zone* zone() { return graph()->zone(); }
   Isolate* isolate() { return zone()->isolate(); }
   Factory* factory() { return isolate()->factory(); }
 
   void GetCachedNodes(NodeVector* nodes);
 
  private:
   Graph* graph_;
   CommonOperatorBuilder* common_;
   JSOperatorBuilder* javascript_;
   MachineOperatorBuilder* machine_;
 
   // TODO(titzer): make this into a simple array.
   SetOncePointer<Node> c_entry_stub_constant_;
   SetOncePointer<Node> undefined_constant_;
   SetOncePointer<Node> the_hole_constant_;
   SetOncePointer<Node> true_constant_;
   SetOncePointer<Node> false_constant_;
   SetOncePointer<Node> null_constant_;
   SetOncePointer<Node> zero_constant_;
   SetOncePointer<Node> one_constant_;
   SetOncePointer<Node> nan_constant_;
+  SetOncePointer<Node> empty_frame_state_;
 
   CommonNodeCache cache_;
 
   Node* ImmovableHeapConstant(Handle<HeapObject> value);
   Node* NumberConstant(double value);
 
   DISALLOW_COPY_AND_ASSIGN(JSGraph);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif