*** old/src/share/vm/oops/instanceKlass.hpp	Fri Sep  9 14:16:13 2011
--- new/src/share/vm/oops/instanceKlass.hpp	Fri Sep  9 14:16:13 2011

*** 1011,1016 ****
--- 1011,1048 ----
    // Return the interesting information for the next previous version
    // of the klass. Returns NULL if there are no more previous versions.
    PreviousVersionInfo* next_previous_version();
  };
  
+ 
+ //
+ // nmethodBucket is used to record dependent nmethods for
+ // deoptimization.  nmethod dependencies are actually <klass, method>
+ // pairs but we really only care about the klass part for purposes of
+ // finding nmethods which might need to be deoptimized.  Instead of
+ // recording the method, a count of how many times a particular nmethod
+ // was recorded is kept.  This ensures that any recording errors are
+ // noticed since an nmethod should be removed as many times are it's
+ // added.
+ //
+ class nmethodBucket: public CHeapObj {
+   friend class VMStructs;
+  private:
+   nmethod*       _nmethod;
+   int            _count;
+   nmethodBucket* _next;
+ 
+  public:
+   nmethodBucket(nmethod* nmethod, nmethodBucket* next) {
+     _nmethod = nmethod;
+     _next = next;
+     _count = 1;
+   }
+   int count()                             { return _count; }
+   int increment()                         { _count += 1; return _count; }
+   int decrement()                         { _count -= 1; assert(_count >= 0, "don't underflow"); return _count; }
+   nmethodBucket* next()                   { return _next; }
+   void set_next(nmethodBucket* b)         { _next = b; }
+   nmethod* get_nmethod()                  { return _nmethod; }
+ };
+ 
  #endif // SHARE_VM_OOPS_INSTANCEKLASS_HPP