Track global cells as special side effects in GVN.

src/handles-inl.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 79 matching lines @@
   Object** roots_array_start = heap->roots_array_start();
   if (roots_array_start <= handle &&
       handle < roots_array_start + Heap::kStrongRootListLength &&
       heap->RootCanBeTreatedAsConstant(
         static_cast<Heap::RootListIndex>(handle - roots_array_start))) {
     return true;
   }
   if (!AllowHandleDereference::IsAllowed()) return false;
   if (mode == INCLUDE_DEFERRED_CHECK &&
       !AllowDeferredHandleDereference::IsAllowed()) {
-    // Accessing maps and internalized strings is safe.
+    // Accessing cells, maps and internalized strings is safe.
+    if (heap_object->IsCell()) return true;
     if (heap_object->IsMap()) return true;
     if (heap_object->IsInternalizedString()) return true;
     return !heap->isolate()->IsDeferredHandle(handle);
   }
   return true;
 }
 #endif
 
 
 
@@ skipping 89 matching lines @@
   current->level = level_;
   ASSERT_EQ(current->next, current->limit);
   current->limit = limit_;
 }
 
 #endif
 
 } }  // namespace v8::internal
 
 #endif  // V8_HANDLES_INL_H_