Bug 605352 - JM: avoid double-pin in x64 FrameState:syncFe (r=sstangl)

js/src/methodjit/FrameState-inl.h

@@ -597,13 +597,13 @@ FrameState::syncFe(FrameEntry *fe)
 
         /* Get a register if necessary, without clobbering its pair. */
         if (needTypeReg) {
-            if (backing->data.inRegister()) {
+            if (backing->data.inRegister() && !regstate[backing->data.reg()].isPinned()) {
                 pairReg = backing->data.reg();
                 pinReg(backing->data.reg());
             }
             tempRegForType(backing);
         } else if (needDataReg) {
-            if (backing->type.inRegister()) {
+            if (backing->type.inRegister() && !regstate[backing->type.reg()].isPinned()) {
                 pairReg = backing->type.reg();
                 pinReg(backing->type.reg());
             }

js/src/methodjit/FrameState.h

@@ -248,12 +248,14 @@ class FrameState
         }
 
         void pin() {
+            JS_ASSERT(fe_ != NULL);
             assertConsistency();
             save_ = fe_;
             fe_ = NULL;
         }
 
         void unpin() {
+            JS_ASSERT(save_ != NULL);
             assertConsistency();
             fe_ = save_;
             save_ = NULL;