[SYCL] GlueEvent uses now the correct plugins

The SYCL RT code for GlueEvent calls now
the right plugin to create the event that triggers the
dependency chain.
Renamed variables to clarify the source code and avoid
confusions between Context and Plugin

Signed-off-by: Ruyman Reyes <ruyman@codeplay.com>

Author: Ruyk

sycl/source/detail/scheduler/commands.cpp

@@ -161,45 +161,50 @@ void EventCompletionClbk(RT::PiEvent, pi_int32, void *data) {
   EventImplPtr *Event = (reinterpret_cast<EventImplPtr *>(data));
   RT::PiEvent &EventHandle = (*Event)->getHandleRef();
   const detail::plugin &Plugin = (*Event)->getPlugin();
-  Plugin.call<PiApiKind::piEventSetStatus>(EventHandle, CL_COMPLETE);
+  Plugin.call<PiApiKind::piEventSetStatus>(EventHandle, PI_EVENT_COMPLETE);
   delete (Event);
 }
 
 // Method prepares PI event's from list sycl::event's
 std::vector<EventImplPtr> Command::prepareEvents(ContextImplPtr Context) {
   std::vector<EventImplPtr> Result;
   std::vector<EventImplPtr> GlueEvents;
-  for (EventImplPtr &Event : MDepsEvents) {
+  for (EventImplPtr &DepEvent : MDepsEvents) {
     // Async work is not supported for host device.
-    if (Event->is_host()) {
-      Event->waitInternal();
+    if (DepEvent->is_host()) {
+      DepEvent->waitInternal();
       continue;
     }
     // The event handle can be null in case of, for example, alloca command,
     // which is currently synchrounious, so don't generate OpenCL event.
-    if (Event->getHandleRef() == nullptr) {
+    if (DepEvent->getHandleRef() == nullptr) {
       continue;
     }
-    ContextImplPtr EventContext = Event->getContextImpl();
-    const detail::plugin &Plugin = Event->getPlugin();
-    // If contexts don't match - connect them using user event
-    if (EventContext != Context && !Context->is_host()) {
+    ContextImplPtr DepEventContext = DepEvent->getContextImpl();
 
+    // If contexts don't match - connect them using user event
+    if (DepEventContext != Context && !Context->is_host()) {
       EventImplPtr GlueEvent(new detail::event_impl());
       GlueEvent->setContextImpl(Context);
+      EventImplPtr *GlueEventCopy =
+          new EventImplPtr(GlueEvent); // To increase the reference count by 1.
+
       RT::PiEvent &GlueEventHandle = GlueEvent->getHandleRef();
+      auto Plugin = Context->getPlugin();
+      auto DepPlugin = DepEventContext->getPlugin();
+      // Add an event on the current context that
+      // is triggered when the DepEvent is complete
       Plugin.call<PiApiKind::piEventCreate>(Context->getHandleRef(),
                                             &GlueEventHandle);
-      EventImplPtr *GlueEventCopy =
-          new EventImplPtr(GlueEvent); // To increase the reference count by 1.
-      Plugin.call<PiApiKind::piEventSetCallback>(
-          Event->getHandleRef(), CL_COMPLETE, EventCompletionClbk,
+
+      DepPlugin.call<PiApiKind::piEventSetCallback>(
+          DepEvent->getHandleRef(), PI_EVENT_COMPLETE, EventCompletionClbk,
           /*void *data=*/(GlueEventCopy));
       GlueEvents.push_back(GlueEvent);
       Result.push_back(std::move(GlueEvent));
       continue;
     }
-    Result.push_back(Event);
+    Result.push_back(DepEvent);
   }
   MDepsEvents.insert(MDepsEvents.end(), GlueEvents.begin(), GlueEvents.end());
   return Result;