[OpenMP][libomp] Cleanup version script and exported symbols

This patch fixes issues seen once https://reviews.llvm.org/D135402 is applied.

The exports_so.txt file attempts to export functions which may not exist
depending on which features are enabled/disabled in the OpenMP
runtime library. There are not many of these so exporting dummy
symbols is feasible.

* Export dummy __kmp_reset_stats() function when stats is disabled.
* Export dummy debugging data when USE_DEBUGGER is disabled
* Export dummy __kmp_itt_[fini|init]_ittlib() functions
   when ITT Notify is disabled
* Export dummy __kmp_reap_monitor() function when KMP_USE_MONITOR
  is disabled
* Remove __kmp_launch_monitor and __kmp_launch_worker from being exported.
  They have been static symbols since library inception.

Fixes: https://github.com/llvm/llvm-project/issues/58858
Differential Revision: https://reviews.llvm.org/D138049

1 files changed, 7 insertions, 1 deletions

diff --git a/openmp/runtime/src/z_Linux_util.cpp b/openmp/runtime/src/z_Linux_util.cpp
index 7aa704b..b1525a3 100644
--- a/openmp/runtime/src/z_Linux_util.cpp
+++ b/openmp/runtime/src/z_Linux_util.cpp
@@ -979,7 +979,7 @@ void __kmp_exit_thread(int exit_status) {
 #if KMP_USE_MONITOR
 void __kmp_resume_monitor();
 
-void __kmp_reap_monitor(kmp_info_t *th) {
+extern "C" void __kmp_reap_monitor(kmp_info_t *th) {
   int status;
   void *exit_val;
 
@@ -1021,6 +1021,12 @@ void __kmp_reap_monitor(kmp_info_t *th) {
 
   KMP_MB(); /* Flush all pending memory write invalidates.  */
 }
+#else
+// Empty symbol to export (see exports_so.txt) when
+// monitor thread feature is disabled
+extern "C" void __kmp_reap_monitor(kmp_info_t *th) {
+  (void)th;
+}
 #endif // KMP_USE_MONITOR
 
 void __kmp_reap_worker(kmp_info_t *th) {