[openmp][test] The `gtid.cpp` test case fails when OpenMP has been built with `-DLIBOMP_ENABLE_SHARED=False`

[pawosm-arm]

With OpenMP built with the -DLIBOMP_ENABLE_SHARED=False CMake flag, the openmp/runtime/test/tasking/hidden_helper_task/gtid.cpp test case is failing as the linker complains that the __kmp_hidden_helper_threads_num symbol is defined in both libomp.a and gtid.cpp. In gtid.cpp it is defined globally as such:

kmp_int32 __kmp_hidden_helper_threads_num;

There is one more test case which also defines kmp_int32 __kmp_hidden_helper_threads_num, it is the openmp/runtime/test/worksharing/for/kmp_sch_simd_guided.c test case and it defines it as such:

static int __kmp_hidden_helper_threads_num = 0;

Shouldn't it be static in the gtid.cpp test case too?

[llvmbot]

@llvm/issue-subscribers-openmp

Author: Paul Osmialowski (pawosm-arm)

With OpenMP built with the `-DLIBOMP_ENABLE_SHARED=False` CMake flag, the `openmp/runtime/test/tasking/hidden_helper_task/gtid.cpp` test case is failing as the linker complains that the `__kmp_hidden_helper_threads_num` symbol is defined in both `libomp.a` and `gtid.cpp`. In `gtid.cpp` it is defined globally as such:

kmp_int32 __kmp_hidden_helper_threads_num;

There is one more test case which also defines kmp_int32 __kmp_hidden_helper_threads_num, it is the openmp/runtime/test/worksharing/for/kmp_sch_simd_guided.c test case and it defines it as such:

static int __kmp_hidden_helper_threads_num = 0;

Shouldn't it be static in the gtid.cpp test case too?

[shiltian]

@TerryLWilmarth Do we really have to support building libomp as a static library?

[pawosm-arm]

I have a debugger test suite which builds test cases with and without -static, the only way to make it work is to have libomp.a.

[TerryLWilmarth]

Hi Shilei,
Yeah, it's strongly discouraged, but there are still people who need it, so we continue to support it, but only on Linux these days. Here are a couple of cases:
https://discourse.llvm.org/t/building-a-static-llvm-openmp-library/39629
https://discourse.llvm.org/t/building-a-static-library-of-openmp/51606

[pawosm-arm]

A somewhat more general question, is this test case correct in defining this variable global without static?

[TerryLWilmarth]

For this bug, the test should just rename that variable to something without the _kmp* prefix. The __kmp, __kmpc, kmp, pseudo-namespaces are meant for the Intel and LLVM OpenMP runtime.

[pawosm-arm]

Thank you @shiltian