The attached patch adds support for ompt_event_task_dependences and ompt_event_task_dependence_pair events from the OMPT specification . 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:
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.
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.
PS: I have removed the extra leading underscore from the kmp calls because they appeared as underlined.