[Openmp-dev] libgomp.so libiomp5.so softlinks

[Jeff Hammond via Openmp-dev]

The LLVM and Intel OpenMP runtimes are essentially identical.

The LLVM/Intel OpenMP runtime defines the GOMP symbols and works with GCC
OpenMP codes, which is actually a good thing, because the GOMP runtime
performs worse (
https://www.nextplatform.com/2017/03/15/arm-antes-hpc-software-stack/).

There are a number of solutions to your problem.  One is to control
LD_LIBRARY_PATH appropriately.  You can remove LLVM folders from
LD_LIBRARY_PATH and use LD_PRELOAD at runtime or -Wl,-rpath when linking to
tell your LLVM OpenMP binary where the library is.

The best option, of course, is to link statically.  You are a Blue Gene
user so I'm sure you understand the utility of fully static binaries :-)

Regardless of how you solve this, I object to removing the symlinks.  What
is happening because of this is far better than the alternative of having
multiple OpenMP libraries loaded into a single binary.  It is a reasonable
assumption that if you are setting LLVM OpenMP shared libraries in your
global path (LD_LIBRARY_PATH), then you want that library to be used.  If
not, link differently.

Jeff

On Thu, May 2, 2019 at 6:41 PM Ye Luo via Openmp-dev <
openmp-dev at lists.llvm.org> wrote:

> Hi,
> What is the reason of making both libgomp.so libiomp5.so softlinks to
> libomp.so?
> I found them hijacking my application built with GNU and Intel compilers
> when I put llvm library folder on my LD_LIBRARY_PATH. This is very
> annoying. Unless there is a very good reason, I think they need be removed.
> Best,
> Ye
> ===================
> Ye Luo, Ph.D.
> Computational Science Division & Leadership Computing Facility
> Argonne National Laboratory
> _______________________________________________
> Openmp-dev mailing list
> Openmp-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/openmp-dev
>


-- 
Jeff Hammond
jeff.science at gmail.com
http://jeffhammond.github.io/
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