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

[Pavan Balaji]

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
http://www.mcs.anl.gov/~balaji