[OpenMP] Shutdown library on Windows if possible for better OMPT beha…

…vior

On Windows, child workers are terminated by the parent during the normal
program exit process (ExitProcess()) and they are not able to finish generating
their OpenMP events. We can force manual library shut down in __kmpc_end() to
fix this at least for the cases where __kmpc_end() is properly inserted.

Patch by Hansang Bae

Differential Revision: https://reviews.llvm.org/D52628

llvm-svn: 343619

openmp/runtime/src/kmp_csupport.cpp

@@ -71,6 +71,14 @@ void __kmpc_end(ident_t *loc) {
 
     __kmp_internal_end_thread(-1);
   }
+#if KMP_OS_WINDOWS && OMPT_SUPPORT
+  // Normal exit process on Windows does not allow worker threads of the final
+  // parallel region to finish reporting their events, so shutting down the
+  // library here fixes the issue at least for the cases where __kmpc_end() is
+  // placed properly.
+  if (ompt_enabled.enabled)
+    __kmp_internal_end_library(__kmp_gtid_get_specific());
+#endif
 }
 
 /*!