Undefined behaviour in hotspot

[Andrew Hughes]

----- Original Message -----
> Hi Volker,
> 
> * Volker Simonis <volker.simonis at gmail.com> [2014-04-23 13:47]:
> > So to cut a long story short, I've identified '-fdevirtualize' as the
> > culprit.
> > '-fdevirtualize' is automatically set if we compile with -O2 but if I
> > compile
> > macroAssembler_x86.o only with '-O2 -fno-devirtualize' I get a VM which at
> > least starts up and passes some smoke tests.
> 
> Aha, Andrew Haley just walked me through similar logic and the same
> flag! Though I don't really understand how (either of) you jumped from
> miscompiled-code to -fno-devirtualize.
> 
> > @Omair: could you please verify this. I haven't tried x86_64 until now
> > so I can not say if this fix also helps there.
> 
> Confirmed. On i686, Hotspot built with this is good enough to run javac to
> compile small programs. I will test x86_64 now.
> 
> Thanks,
> Omair
> 
> --
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> 

This should turn it off in the right place:

http://cr.openjdk.java.net/~andrew/8041658/webrev.01/

Bug: https://bugs.openjdk.java.net/browse/JDK-8041658
-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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