[mpich-discuss] MPICH 3.1.4 segfaults Clang 3.6.1 and 3.7

[Balaji, Pavan]

You can explicitly disable weak symbols using --disable-weak-symbols.

  -- Pavan





On 9/3/15, 11:42 PM, "Torbjörn Klatt" <opensource at torbjoern-klatt.de> wrote:

>Hello,
>
>thanks Rob and Pavan for the reply.
>
>Yes, it's on Linux (openSUSE 13.2 64bit to be precise, Clang compiled with 
>distro's default GCC 4.8.3).
>
>After testing Clang 3.4.2 and seeing it to fail with the same segfault, I 
>assume users how want to use MPICH with Clang are stuck with Clang 3.3. You 
>may think about writing that down somewhere for future users.
>
>For now I'll keep using Clang 3.3 and GCC 5.x for my MPI development but keep 
>on testing future Clang and MPICH versions.
>
>Torbjörn
>
>
>On Thursday 03 September 2015 01:11:54 Balaji, Pavan wrote:
>> This is only an issue with clang on Linux, right?  (I couldn't quite tell
>> from the email chain).  On Mac OS/X, we already disable weak symbols, so
>> this shouldn't occur.
> 
>> Can someone remind me why we didn't simply add a check in our configure to
>> say if compiler == clang, then disable weak symbols?
> 
>>   -- Pavan
>> 
>> 
>> 
>> 
>> 
>> On 9/2/15, 4:57 PM, "Rob Latham" <robl at mcs.anl.gov> wrote:
>> 
>> 
>> >
>> >
>> >On 09/02/2015 02:29 AM, Torbjörn Klatt wrote:
>> >
>> >> Hello,
>> >>
>> >>
>> >>
>> >> I'm trying to use MPICH 3.1.4 with Clang and tried Clang 3.6.1 and 3.7.
>> >> With
> both versions Clang segfaults at the same point:
>> >>
>> >>
>> >>
>> >> pt2pt/greq_start.c:239:62: error: alias must point to a defined variable
>> >> or
> function
>> >> 
>> >>          MPIX_Grequest_class *greq_class)
>> >> 
>> >> __attribute__((weak,alias("MPIX_Grequest_class_create")));
>> >>
>> >>
>> >>
>> >> I've filed a LLVM bug [1] with more details, however without response
>> >> yet.
>> >>
>> >>
>> >>
>> >>
>> >> MPICH was configured with:
>> >>
>> >>
>> >>
>> >> CC=clang CXX=clang++ /opt/toolchains/src/mpi/mpich/3.1.4/configure --
>> >> srcdir=/opt/toolchains/src/mpi/mpich/3.1.4 --
>> >> prefix=/opt/toolchains/clang/3.7/libraries/mpi/mpich/3.1.4
>> >> --enable-g=most --
> enable-fast=all --enable-fortran=all --enable-cxx
>> >>
>> >>
>> >>
>> >>
>> >> Is this a known MPICH problem or am I doing something wrong?
>> >
>> >
>> >It's been a long-standing annoyance on our end as well:
>> >
>> >We sort of fixed this two+ years ago:
>> >http://trac.mpich.org/projects/mpich/ticket/1815
>> >
>> >then something happened about 6-ish months ago:
>> >http://trac.mpich.org/projects/mpich/ticket/2236
>> >
>> >My ubuntu bug report appears to have garnered exactly zero attention:
>> >https://bugs.launchpad.net/ubuntu/+source/llvm-toolchain-snapshot/+bug/1439
>> >865
> 
>> >As it's a clang compiler error, it's hard to know what the workaround 
>> >would be.  Thanks for trying 3.6.1 and 3.7.    At least we can rule out 
>> >"fixed in newer versions"
>> >
>> >You will find this same segfault in mpich-master: we haven't done 
>> >anything on our end to work around it, unfortunately.
>> >
>> >==rob
>> >
>-- 
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