Merge a number of assertion failure fixes to the 3.0 branch.

src/builtins.cc

 // 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 350 matching lines @@
 
 static bool ArrayPrototypeHasNoElements(Context* global_context,
                                         JSObject* array_proto) {
   // This method depends on non writability of Object and Array prototype
   // fields.
   if (array_proto->elements() != Heap::empty_fixed_array()) return false;
   // Hidden prototype
   array_proto = JSObject::cast(array_proto->GetPrototype());
   ASSERT(array_proto->elements() == Heap::empty_fixed_array());
   // Object.prototype
-  array_proto = JSObject::cast(array_proto->GetPrototype());
+  Object* proto = array_proto->GetPrototype();
+  if (proto == Heap::null_value()) return false;
+  array_proto = JSObject::cast(proto);
   if (array_proto != global_context->initial_object_prototype()) return false;
   if (array_proto->elements() != Heap::empty_fixed_array()) return false;
   ASSERT(array_proto->GetPrototype()->IsNull());
   return true;
 }
 
 
 MUST_USE_RESULT
 static inline MaybeObject* EnsureJSArrayWithWritableFastElements(
     Object* receiver) {
@@ skipping 1154 matching lines @@
       if (entry->contains(pc)) {
         return names_[i];
       }
     }
   }
   return NULL;
 }
 
 
 } }  // namespace v8::internal