--- a/hotspot/src/share/vm/code/codeBlob.hpp	Tue Sep 15 11:09:34 2009 -0700
+++ b/hotspot/src/share/vm/code/codeBlob.hpp	Tue Sep 15 21:53:47 2009 -0700
@@ -175,6 +175,8 @@
                             OopClosure* keep_alive,
                             bool unloading_occurred);
   virtual void oops_do(OopClosure* f) = 0;
+  // (All CodeBlob subtypes other than NMethod currently have
+  // an empty oops_do() method.
 
   // OopMap for frame
   OopMapSet* oop_maps() const                    { return _oop_maps; }