Undefined behaviour in hotspot
gnu.andrew at redhat.com
Wed Apr 23 21:13:01 UTC 2014
----- 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.
> PGP Key: 66484681 (http://pgp.mit.edu/)
> Fingerprint = F072 555B 0A17 3957 4E95 0056 F286 F14F 6648 4681
This should turn it off in the right place:
Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)
PGP Key: 248BDC07 (https://keys.indymedia.org/)
Fingerprint = EC5A 1F5E C0AD 1D15 8F1F 8F91 3B96 A578 248B DC07
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