[OMPT] Add support for ompt_event_task_dependences and ompt_event_task_dependence_pair

The attached patch adds support for ompt_event_task_dependences and
ompt_event_task_dependence_pair events from the OMPT specification [1]. These
events only apply to OpenMP 4.0 and 4.1 (aka 4.5) because task dependencies
were introduced in 4.0.

With respect to the changes:

ompt_event_task_dependences
According to the specification, this event is raised after the task has been
created, thefore this event needs to be raised after ompt_event_task_begin
(in __kmp_task_start). However, the dependencies are known at
__kmpc_omp_task_with_deps which occurs before __kmp_task_start. My modifications
extend the ompt_task_info_t struct in order to store the dependencies of the
task when _kmpc_omp_task_with_deps occurs and then they are emitted in
__kmp_task_start just after raising the ompt_event_task_begin. The deps field
is allocated and valid until the event is raised and it is freed and set
to null afterwards.

ompt_event_task_dependence_pair
The processing of the dependences (i.e. checking whenever a dependence is
already satisfied) is done within __kmp_process_deps. That function checks
every dependence and calls the __kmp_track_dependence routine which gives some
support for graphical output. I used that routine to emit the dependence pair
but I also needed to know the sink_task. Despite the fact that the code within
KMP_SUPPORT_GRAPH_OUTPUT refers to task_sink it may be null because
sink->dn.task (there's a comment regarding this) and in fact it does not point
to a proper pointer value because the value is set in node->dn.task = task;
after the __kmp_process_deps calls in __kmp_check_deps. I have extended the
__kmp_process_deps and __kmp_track_dependence parameter list to receive the
sink_task.

[1] https://github.com/OpenMPToolsInterface/OMPT-Technical-Report/blob/target/ompt-tr.pdf

Patch by Harald Servat
Differential Revision: http://reviews.llvm.org/D14746

llvm-svn: 259038

1 files changed, 20 insertions, 0 deletions

diff --git a/openmp/runtime/src/kmp_tasking.c b/openmp/runtime/src/kmp_tasking.c
index fc9348c94e2..3df0c9e73dd 100644
--- a/openmp/runtime/src/kmp_tasking.c
+++ b/openmp/runtime/src/kmp_tasking.c
@@ -462,6 +462,22 @@ __kmp_task_start( kmp_int32 gtid, kmp_task_t * task, kmp_taskdata_t * current_ta
             taskdata->ompt_task_info.function);
     }
 #endif
+#if OMP_40_ENABLED && OMPT_SUPPORT && OMPT_TRACE
+    /* OMPT emit all dependences if requested by the tool */
+    if (ompt_enabled && taskdata->ompt_task_info.ndeps > 0 &&
+        ompt_callbacks.ompt_callback(ompt_event_task_dependences))
+	{
+        ompt_callbacks.ompt_callback(ompt_event_task_dependences)(
+            taskdata->ompt_task_info.task_id,
+            taskdata->ompt_task_info.deps,
+            taskdata->ompt_task_info.ndeps
+        );
+		/* We can now free the allocated memory for the dependencies */
+		KMP_OMPT_DEPS_FREE (thread, taskdata->ompt_task_info.deps);
+        taskdata->ompt_task_info.deps = NULL;
+        taskdata->ompt_task_info.ndeps = 0;
+    }
+#endif /* OMP_40_ENABLED && OMPT_SUPPORT && OMPT_TRACE */
 
     return;
 }
@@ -760,6 +776,10 @@ __kmp_task_init_ompt( kmp_taskdata_t * task, int tid, void * function )
         task->ompt_task_info.function = function;
         task->ompt_task_info.frame.exit_runtime_frame = NULL;
         task->ompt_task_info.frame.reenter_runtime_frame = NULL;
+#if OMP_40_ENABLED
+        task->ompt_task_info.ndeps = 0;
+        task->ompt_task_info.deps = NULL;
+#endif /* OMP_40_ENABLED */
     }
 }
 #endif