Address lookup

Several components in Score-P rely on mapping addresses to source-code locations like filename and line number. Score-P uses the BFD library for this mapping and takes addresses within the instrumented binary as well as within shared objects loaded at program startup into account.

If, however, the binary loads additional shared objects during runtime via dlopen, addresses from within these shared objects are by default, not considered for lookup.

To change this behavior, Score-P can intercept dlopen/dlclose calls using the dynamic linker's auditing API (man 7 rtld-audit), if desired. To do so, prefix only the application command with LD_AUDIT=<scorep_prefix>/lib/libscorep_rtld_audit.so. For an MPI application started with mpiexec where environment variables are exported to the application via -x, it would, e.g., look like this:

$ mpiexec -np 4 -x LD_AUDIT=/opt/scorep/lib/libscorep_rtld_audit.so ./jacobi

Note that you must not export LD_AUDIT or put it in front of launchers like mpiexec or srun; linker auditing takes place immediately after LD_AUDIT is set and results in error messages about missing symbols if not used together with Score-P instrumented binaries.

You can query the installation-specific value of LD_AUDIT via:

$ scorep-info ldaudit