Fix intermittent crashes caused by unexpected GCs in...

src/objects.cc

 // Copyright 2006-2009 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 5143 matching lines @@
     // code zero) it will always occupy the first entry if present.
     DescriptorArray* descriptors = this->map()->instance_descriptors();
     DescriptorReader r(descriptors);
     if (!r.eos() && (r.GetKey() == key) && r.IsProperty()) {
       ASSERT(r.type() == FIELD);
       return FastPropertyAt(r.GetFieldIndex());
     }
   }
 
   // Only attempt to find the hidden properties in the local object and not
-  // in the prototype chain.
+  // in the prototype chain.  Note that HasLocalProperty() can cause a GC in
+  // the general case, but in this case we know it won't hit an interceptor.
   if (!this->HasLocalProperty(key)) {
     // Hidden properties object not found. Allocate a new hidden properties
     // object if requested. Otherwise return the undefined value.
     if (create_if_needed) {
       Object* obj = Heap::AllocateJSObject(
           Top::context()->global_context()->object_function());
       if (obj->IsFailure()) {
         return obj;
       }
       return this->SetProperty(key, obj, DONT_ENUM);
@@ skipping 2325 matching lines @@
   // No break point.
   if (break_point_objects()->IsUndefined()) return 0;
   // Single beak point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 } }  // namespace v8::internal