llvm dev - Nov 2013 - [LLVMdev] MCJIT RemoteMemoryManager Failures on ARM

Hi Andrew & Takumi,

I'm including you guys because you seem to know what should and what
shouldn't work, given your recent changes to the XFAILs. Feel free to
exclude yourselves, or include other folks.

I'm having a problem with a self-hosting ARM bot described here:

http://llvm.org/bugs/show_bug.cgi?id=18057

Basically, allocateSpace() sometimes works, sometimes doesn't. I
couldn't
see much wrong with the code, and the call graph looks valid, so I'm
guessing it's something in the higher logic (message passing) that is
non-deterministically failing.

I even tried to run manually several times in a row and sometimes it fails,
sometimes it doesn't, so it's not a hard error in code generation, but
the
GCC generated binary NEVER fails, while the Clang generated ones, sometimes
do.

I want to introduce a self-hosting buildbot on ARM, but this is stopping me
from doing so, since the tests fail randomly at every run. Any ideas?

Thanks,
--renato
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IMHO, tests may be suppressed with lit.local.cfg, only if;

  - The issue is filed -- PR18057
  - There is at least one person responsible to watch on this issue.

Suppression is not good idea. But it should be done anyways if
responsible person were there.
I would not help you since I don't have any arm boxes.

Thank you.

2013/11/26 Renato Golin <renato.golin at
linaro.org>:
> Hi Andrew & Takumi,
>
> I'm including you guys because you seem to know what should and what
> shouldn't work, given your recent changes to the XFAILs. Feel free to
> exclude yourselves, or include other folks.
>
> I'm having a problem with a self-hosting ARM bot described here:
>
> http://llvm.org/bugs/show_bug.cgi?id=18057
>
> Basically, allocateSpace() sometimes works, sometimes doesn't. I
couldn't
> see much wrong with the code, and the call graph looks valid, so I'm
> guessing it's something in the higher logic (message passing) that is
> non-deterministically failing.
>
> I even tried to run manually several times in a row and sometimes it fails,
> sometimes it doesn't, so it's not a hard error in code generation,
but the
> GCC generated binary NEVER fails, while the Clang generated ones, sometimes
> do.
>
> I want to introduce a self-hosting buildbot on ARM, but this is stopping me
> from doing so, since the tests fail randomly at every run. Any ideas?
>
> Thanks,
> --renato

On 26 November 2013 01:55, NAKAMURA Takumi <geek4civic at gmail.com>
wrote:
> IMHO, tests may be suppressed with lit.local.cfg, only if;
>
They were disabled, but then re-enabled because they don't fail on normal
build bots, but they do on self-host bots. So, I think this is a more
serious issue than just MCJIT, I think this is a Clang miscompilation. I'll
try on x86 to see if the self-hosting problem appears.


  - The issue is filed -- PR18057
>   - There is at least one person responsible to watch on this issue.
>
Yes, but without priority, the bug will be forgotten.


I would not help you since I don't have any arm
boxes.
>
I have an ARM box which you can SSH into, if you need. My knowledge of how
the MCJIT should behave is very limited. If you're willing to take a look,
I'd do my best to help you working on ARM.

cheers,
--renato
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