RFR: 8252505: C1/C2 compiler support for blackholes [v11]

Vladimir Ivanov vladimir.x.ivanov at oracle.com
Wed Dec 2 12:18:48 UTC 2020


>> src/hotspot/share/opto/doCall.cpp line 115:
>>
>>> 113:
>>> 114:   // Try blackholing a method
>>> 115:   if (callee->is_loaded() &&
>>
>> The check can be turned into a property on `ciMethod` and the result cached there.
> 
> Yes, but only partially, because C1 and C2 check their own directive sets, and C2 also checks for matching rule. But it does skip unloaded methods more cleanly if we move the first two checks to `ciMethod`. Fixed.

I would assume that `-XX:CompileCommand=blackhole,method` marks the 
method as a blackhole for the whole JVM instance (irrespective of what 
JIT is used or . Why can't you perform the query from the ciMethod 
itself? Or do you see controlling it on per-compilation basis valuable?

Best regards,
Vladimir Ivanov



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