[Bug driver/57123] New: code compiled and linked with -fopenmp does not load the correct omp library at run-time

[Bug driver/57123] New: code compiled and linked with -fopenmp does not load the correct omp library at run-time

[wd11 at leicester dot ac.uk]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57123

             Bug #: 57123
           Summary: code compiled and linked with -fopenmp does not load
                    the correct omp library at run-time
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: driver
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: wd11@leicester.ac.uk


code compiled and linked with -fopenmp will, at run-time, load the first
libgomp it finds in the LD_LIBRARY_PATH (on linux). However, this may not be
the correct one, causing run-time failure. This problem manifests itself if,
for example, using a more recent version of gcc (4.7.0) than the default OS
version (4.3.4), when upon running I get

mycmd: /usr/lib64/libgomp.so.1: version `OMP_3.0' not found (required by
mylib.so)

where mycmd was made using gcc 4.7.0 (at /somepath/gcc/4.7.0/bin/gcc) with
option -fopenmp both at compiling and linking. This behaviour is at odds with
the documentation, according to which -fopenmp arranges for the automatic
linking of the [correct] OpenMP library.

Note that I can "fix" the problem by adding the path of the correct library,
/somepath/gcc/4.7.0/lib64, to the environment variable LD_LIBRARY_PATH.
However, this fiddling with the operating system is not desirable and
potentially dangerous, as it may break the operating system itself. Instead,
the correct library path should be hard-wired into the executable upon making
it, i.e. at linking the -fopenmp option should effectuate to (-Wl)
-rpath=/somepath/gcc/4.7.0/lib64. Note also that adding the correct path to the
LD_RUN_PATH environment variable at compiling and linking (and running) has not
the desired effect.

[Bug driver/57123] code compiled and linked with -fopenmp does not load the correct omp library at run-time

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57123

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |jakub at gcc dot gnu.org
         Resolution|                            |INVALID

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-30 12:12:05 UTC ---
That is a user error, gcc isn't supposed to handle this for you.  If you have
multiple versions of libgomp.so on your system, just use -Wl,-rpath,/some/path/
or LD_LIBRARY_PATH to point the program at the right version.
Like glibc, libgomp is symbol versioned and backward compatible, keeping the
same SONAME, so you really want the latest version of the library from all
versions needed by programs that link against it.