clang-3.4 hangs on package alliance 5.0-20120515-6

[Sylvestre Ledru]

On 01/05/2014 23:36, Nicolas Sévelin-Radiguet wrote:
> [04/09/2014 08:33 AM] Sylvestre Ledru:
>> On 08/04/2014 23:28, Nicolas Sévelin-Radiguet wrote:
>>> On 04/08/2014 10:51 PM, Sylvestre Ledru wrote:
>>>> On 08/04/2014 21:36, Nicolas Sévelin-Radiguet wrote:
>>>>> Hello everyone,
>>>>>
>>>>> While fixing some FTBFS with clang instead of gcc, I came across a
>>>>> bug
>>>>> in clang (at least I think so).
>>>>>
>>>>> The package I am working on is alliance 5.0-20120515-6 [0] which is
>>>>> failing to build due to -Wreturn-type errors [1]. After applying the
>>>>> following patch [2] to get rid of these, clang hangs (eats CPU) and
>>>>> nothing happens even after a few minutes [3].
>>>>> The files needed to reproduce this behavior are here [4]:
>>>>> - expy-0fa6b4.sh is the command line
>>>>> - expy-0fa6b4.c is the source
>>>>>
>>>>> The source, with the patch applied, builds fine with gcc [5].
>>>>> Please note that I am not familiar at all with this particular
>>>>> package.
>>>> Is it this bug ?
>>>> http://clang.debian.net/status.php?version=3.4&key=BUILD_TIMEOUT ?
>>>> http://llvm.org/bugs/show_bug.cgi?id=16821
>>>>
>>>> Thanks
>>>> S
>>>>
>>> Humm, looks like it.
>>> When modifying the command line (the rest of the line being the same):
>>> -D "_FORTIFY_SOURCE=2" -O2 hangs
>>> -D "_FORTIFY_SOURCE=2" -O1 works
>>> -O2 hangs
>>> -O1 works.
>>> So it looks like even without -D "_FORTIFY_SOURCE=2", clang hangs.
>> Oh.
>> A reduced test case of this file could help and, if different from bug
>> 16821, please report it :)
>>
>> Thanks,
>> Sylvestre
>>
> Hi,
>
> Some news on this.
> This is definitely not the same bug:
> If I understand correctly, llvm bug 16821 refers to generated code
> which loops infinitely when executed. Am I right ?
yes

> If that's the case, I am not able to reproduce the test cases provided
> in the bug report. Can anyone confirm and/or correct me ?
>
Which version of clang do you use?
> The bug I have in the alliance package is about clang taking forever
> to compile the source. I will try to generated a reduced test case. It
> looks like c-reduce is the appropriate tool to do that, right ?
>
I am not really sure that creduce can handle such case. Just give it a try.
> About the 'build time out' category on debian.clang.net, it looks like
> it is not related to bug 16821 (at least not all packages are). I was
> able to build some of them. Buildlogs are here:
> https://github.com/nonas/debian-clang/tree/master/tests/build_timeout/buildlogs
> See files attempted.txt, failed.txt and successful.txt.
Looks like you have some issues here (but that is great news that you
cannot reproduce the bug):
https://github.com/nonas/debian-clang/blob/master/tests/build_timeout/buildlogs/gcc-4.8_4.8.2-21_amd64-20140427-2130.build
https://github.com/nonas/debian-clang/blob/master/tests/build_timeout/buildlogs/scilab_5.5.0-2_amd64-20140427-1025.build

Interesting that it is working for you. Maybe a more recent version of
gcc or libc fixed the bug.


Cheers,
sylvestre