[OpenMP] libomp: Add itt notifications to sync dependent tasks.

[AndreyChurbanov]

Summary

Intel Inspector uses itt notifications to analyze code execution, and it reports race conditions in dependent tasks.
This patch fixes the issue notifying Inspector on tasks dependency synchronizations.

[jlpeyton]

LGTM

openmp/runtime/src/kmp_taskdeps.h

 
 static inline void __kmp_node_deref(kmp_info_t *thread, kmp_depnode_t *node) {
   if (!node)
     return;
 
   kmp_int32 n = KMP_ATOMIC_DEC(&node->dn.nrefs) - 1;
   KMP_DEBUG_ASSERT(n >= 0);
   if (n == 0) {
+#if USE_ITT_BUILD && USE_ITT_NOTIFY
+    __itt_sync_destroy(node);
+#endif
     KMP_ASSERT(node->dn.nrefs == 0);
 #if USE_FAST_MEMORY
     __kmp_fast_free(thread, node);
 #else
     __kmp_thread_free(thread, node);
 #endif
   }
 }
static inline void __kmp_release_deps(kmp_int32 gtid, kmp_taskdata_t *task) {
   node->dn.task =
       NULL; // mark this task as finished, so no new dependencies are generated
   KMP_RELEASE_DEPNODE(gtid, node);
 
   kmp_depnode_list_t *next;
   kmp_taskdata_t *next_taskdata;
   for (kmp_depnode_list_t *p = node->dn.successors; p; p = next) {
     kmp_depnode_t *successor = p->node;
+#if USE_ITT_BUILD && USE_ITT_NOTIFY
+    __itt_sync_releasing(successor);
+#endif
     kmp_int32 npredecessors = KMP_ATOMIC_DEC(&successor->dn.npredecessors) - 1;
 
     // successor task can be NULL for wait_depends or because deps are still
     // being processed
     if (npredecessors == 0) {
+#if USE_ITT_BUILD && USE_ITT_NOTIFY
+      __itt_sync_acquired(successor);
+#endif
       KMP_MB();
       if (successor->dn.task) {
         KA_TRACE(20, ("__kmp_release_deps: T#%d successor %p of %p scheduled "
                       "for execution.\n",
                       gtid, successor->dn.task, task));
         // If a regular task depending on a hidden helper task, when the
         // hidden helper task is done, the regular task should be executed by
         // its encountering team.

openmp/runtime/src/kmp_taskdeps.cpp

static void __kmp_init_node(kmp_depnode_t *node) {
   for (int i = 0; i < MAX_MTX_DEPS; ++i)
     node->dn.mtx_locks[i] = NULL;
   node->dn.mtx_num_locks = 0;
   __kmp_init_lock(&node->dn.lock);
   KMP_ATOMIC_ST_RLX(&node->dn.nrefs, 1); // init creates the first reference
 #ifdef KMP_SUPPORT_GRAPH_OUTPUT
   node->dn.id = KMP_ATOMIC_INC(&kmp_node_id_seed);
 #endif
+#if USE_ITT_BUILD && USE_ITT_NOTIFY
+  __itt_sync_create(node, "OMP task dep node", NULL, 0);
+#endif
 }
 
 static inline kmp_depnode_t *__kmp_node_ref(kmp_depnode_t *node) {
   KMP_ATOMIC_INC(&node->dn.nrefs);
   return node;
 }
 
 enum { KMP_DEPHASH_OTHER_SIZE = 97, KMP_DEPHASH_MASTER_SIZE = 997 };