[OpenMP][OMPT] Fix unsafe initialization of ompt_data_t objects

Initializing an ompt_data_t object using the pointer union member is potentially
unsafe in 32-bit programs.  This change fixes the issue
by using the constant, ompt_data_none.

Patch by Hansang Bae

Differential Revision: https://reviews.llvm.org/D52046

llvm-svn: 343785
diff --git a/openmp/runtime/src/kmp_runtime.cpp b/openmp/runtime/src/kmp_runtime.cpp
index e0c15cd..522e4f5 100644
--- a/openmp/runtime/src/kmp_runtime.cpp
+++ b/openmp/runtime/src/kmp_runtime.cpp
@@ -1209,8 +1209,7 @@
 #endif /* OMP_40_ENABLED */
 
 #if OMPT_SUPPORT
-  ompt_data_t ompt_parallel_data;
-  ompt_parallel_data.ptr = NULL;
+  ompt_data_t ompt_parallel_data = ompt_data_none;
   ompt_data_t *implicit_task_data;
   void *codeptr = OMPT_LOAD_RETURN_ADDRESS(global_tid);
   if (ompt_enabled.enabled &&
@@ -1477,8 +1476,7 @@
     master_set_numthreads = master_th->th.th_set_nproc;
 
 #if OMPT_SUPPORT
-    ompt_data_t ompt_parallel_data;
-    ompt_parallel_data.ptr = NULL;
+    ompt_data_t ompt_parallel_data = ompt_data_none;
     ompt_data_t *parent_task_data;
     omp_frame_t *ompt_frame;
     ompt_data_t *implicit_task_data;
@@ -3726,7 +3724,7 @@
     }
     root_thread->th.th_info.ds.ds_gtid = gtid;
 #if OMPT_SUPPORT
-    root_thread->th.ompt_thread_info.thread_data.ptr = NULL;
+    root_thread->th.ompt_thread_info.thread_data = ompt_data_none;
 #endif
     root_thread->th.th_root = root;
     if (__kmp_env_consistency_check) {
@@ -5601,7 +5599,7 @@
   ompt_data_t *thread_data;
   if (ompt_enabled.enabled) {
     thread_data = &(this_thr->th.ompt_thread_info.thread_data);
-    thread_data->ptr = NULL;
+    *thread_data = ompt_data_none;
 
     this_thr->th.ompt_thread_info.state = omp_state_overhead;
     this_thr->th.ompt_thread_info.wait_id = 0;