[mpich-devel] Weak symbols, clang, and users compiling with -fvisibility=hidden

Pavan Balaji balaji at mcs.anl.gov
Mon Jan 6 13:50:25 CST 2014

Hi Jed,

This attribute is tested in configure before it’s added to mpi.h.in.  There was some breakage that Ken recently fixed.  Are you using the git mpich/master version for this?  Also, which version of clang is this?

  — Pavan

On Jan 6, 2014, at 1:43 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> Jed Brown <jedbrown at mcs.anl.gov> writes:
>> So in summary, we can't have __attribute__((weak,alias("PMPI_..."))) in
>> the header because:
>>  1. it does not compile with gcc
> It also does not compile with the new version of clang.
> conftest.c:37:34: error: alias must point to a defined variable or function
> int foo(void) __attribute((weak, alias("__foo")));
>                                 ^
>>  2. it breaks PMPI interposition with clang
>>  3. it breaks -fvisibility=hidden with clang

Pavan Balaji

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