hotspot JIT producing incorrect code -how should I report a bug?

Keith McNeill mcneill at
Tue Jul 8 12:50:40 PDT 2008

Hotspot is producing incorrect code deep in the bowels of our system.  A 
simple example doesn't produce the problem. 

The code in question works as expected until the method is JITted.  
Using -XX:+PrintCompliation I can tell that once the method is compiled 
the method in question starts behaving incorrectly.  

I'd liked the bug to get fixed but I don't have a clue how to give you 
guys a reasonable bug report that would have enough information to 
enable the bug to be fixed.  I tried producing a simple example of the 
problem and that didn't produce the problem (I wasn't too surprised 
about that).

I could imagine that it would be useful to send you the .class file in 
question and the JITted code in question.  Is there anyway to get 
hotspot to dump the JITted code?  Or get hotspot to dump some state that 
would make it useful?  Is there some other way to get the information 
to  the correct people?



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