Protect calls to KMP_DLSYM in kmp_alloc.cpp

[alban.bridonneau]

Summary

This fixes static builds of openmp. They currently
fail at runtime because of an "undefined symbol"
error. dlsym is only available for dynamic builds.

[protze.joachim]

Which platform has the problem? Static build does not preclude linking libdl, which will provide dlsym. So, an alternative solution might be to link libdl for the static library?

kmp_ftn_entry.h uses the same function in several places. No issues there?

openmp/runtime/src/kmp_alloc.cpp

1364

This variable should at least be set to 0/false

[alban.bridonneau]

The issue was detected on Linux, AArch64.

Other calls to dlsym in kmp_alloc.cpp are already protected by that define, which is why i thought it made sense to do the same here.
It seems that kmp_ftn_entry.h was not included in my build. I'll go through the CMake files to see what happened.

Thanks

[protze.joachim]

kmp_ftn_entry.h provides the implementation for all OpenMP API functions. I'm curious to see what happened, that it is not included.

[alban.bridonneau]

Hi!
Sorry for the delay, i had a couple of concurrent tasks.

kmp_ftn_entry.h was indeed included, i had just looked at it wrong. Also, we are going to follow your suggestion and link against libdl, so this patch is no longer needed

Thanks for the review!

openmp/runtime/src/kmp_alloc.cpp

#if KMP_OS_UNIX && KMP_DYNAMIC_LIB
   mk_hbw_preferred_hugetlb = NULL;
   mk_dax_kmem = NULL;
   mk_dax_kmem_all = NULL;
   mk_dax_kmem_preferred = NULL;
 #endif
 }
 // Preview of target memory support
 void __kmp_init_target_mem() {
+#if KMP_DYNAMIC_LIB
   *(void **)(&kmp_target_alloc_host) = KMP_DLSYM("llvm_omp_target_alloc_host");
   *(void **)(&kmp_target_alloc_shared) =
       KMP_DLSYM("llvm_omp_target_alloc_shared");
   *(void **)(&kmp_target_alloc_device) =
       KMP_DLSYM("llvm_omp_target_alloc_device");
   *(void **)(&kmp_target_free) = KMP_DLSYM("omp_target_free");
   __kmp_target_mem_available = kmp_target_alloc_host &&
                                kmp_target_alloc_shared &&
                                kmp_target_alloc_device && kmp_target_free;
+#endif
 }
 
 omp_allocator_handle_t __kmpc_init_allocator(int gtid, omp_memspace_handle_t ms,
                                              int ntraits,
                                              omp_alloctrait_t traits[]) {
   // OpenMP 5.0 only allows predefined memspaces
   KMP_DEBUG_ASSERT(ms == omp_default_mem_space || ms == omp_low_lat_mem_space ||
                    ms == omp_large_cap_mem_space || ms == omp_const_mem_space ||