Make state stack thread local. When using Lockers the state stacks of...

src/vm-state.h

Index: src/vm-state.h
===================================================================
--- src/vm-state.h	(revision 5653)
+++ src/vm-state.h	(working copy)
@@ -28,6 +28,8 @@
 #ifndef V8_VM_STATE_H_
 #define V8_VM_STATE_H_
 
+#include "top.h"
+
 namespace v8 {
 namespace internal {
 
@@ -44,16 +46,16 @@
 
   // Used for debug asserts.
   static bool is_outermost_external() {
-    return current_state_ == 0;
+    return Top::current_vm_state() == 0;
   }
 
   static StateTag current_state() {
-    VMState* state = reinterpret_cast<VMState*>(current_state_);
+    VMState* state = Top::current_vm_state();
     return state ? state->state() : EXTERNAL;
   }
 
   static Address external_callback() {
-    VMState* state = reinterpret_cast<VMState*>(current_state_);
+    VMState* state = Top::current_vm_state();
     return state ? state->external_callback_ : NULL;
   }
 
@@ -63,8 +65,6 @@
   VMState* previous_;
   Address external_callback_;
 
-  // A stack of VM states.
-  static AtomicWord current_state_;
 #else
  public:
   explicit VMState(StateTag state) {}