[UR][Offload] Implement stub functions for mem advise/prefetch

These functions both do nothing if they aren't supported, so are
implemented as functions that do nothing besides fiddle with event
dependencies.

Author: RossBrunton

unified-runtime/source/adapters/offload/enqueue.cpp

@@ -442,3 +442,30 @@ UR_APIEXPORT ur_result_t UR_APICALL urEnqueueUSMMemcpy(
 
   return UR_RESULT_SUCCESS;
 }
+
+UR_APIEXPORT ur_result_t UR_APICALL urEnqueueUSMAdvise(
+    ur_queue_handle_t hQueue, [[maybe_unused]] const void *pMem,
+    [[maybe_unused]] size_t size, [[maybe_unused]] ur_usm_advice_flags_t advice,
+    ur_event_handle_t *phEvent) {
+  // Currently not supported - do nothing
+  if (phEvent) {
+    *phEvent =
+        ur_event_handle_t_::createEmptyEvent(UR_COMMAND_USM_ADVISE, hQueue);
+  }
+  return UR_RESULT_SUCCESS;
+}
+
+UR_APIEXPORT ur_result_t UR_APICALL urEnqueueUSMPrefetch(
+    ur_queue_handle_t hQueue, [[maybe_unused]] const void *pMem,
+    [[maybe_unused]] size_t size,
+    [[maybe_unused]] ur_usm_migration_flags_t flags,
+    uint32_t numEventsInWaitList, const ur_event_handle_t *phEventWaitList,
+    ur_event_handle_t *phEvent) {
+  // Currently not supported - do nothing
+  ol_queue_handle_t Queue;
+  OL_RETURN_ON_ERR(hQueue->nextQueue(Queue));
+  OL_RETURN_ON_ERR(waitOnEvents(Queue, phEventWaitList, numEventsInWaitList));
+  OL_RETURN_ON_ERR(makeEvent(UR_COMMAND_USM_PREFETCH, Queue, hQueue, phEvent));
+
+  return UR_RESULT_SUCCESS;
+}

unified-runtime/source/adapters/offload/ur_interface_loader.cpp

@@ -187,10 +187,10 @@ UR_DLLEXPORT ur_result_t UR_APICALL urGetEnqueueProcAddrTable(
   pDdiTable->pfnMemUnmap = urEnqueueMemUnmap;
   pDdiTable->pfnUSMFill2D = urEnqueueUSMFill2D;
   pDdiTable->pfnUSMFill = urEnqueueUSMFill;
-  pDdiTable->pfnUSMAdvise = nullptr;
+  pDdiTable->pfnUSMAdvise = urEnqueueUSMAdvise;
   pDdiTable->pfnUSMMemcpy2D = urEnqueueUSMMemcpy2D;
   pDdiTable->pfnUSMMemcpy = urEnqueueUSMMemcpy;
-  pDdiTable->pfnUSMPrefetch = nullptr;
+  pDdiTable->pfnUSMPrefetch = urEnqueueUSMPrefetch;
   pDdiTable->pfnReadHostPipe = nullptr;
   pDdiTable->pfnWriteHostPipe = nullptr;
   return UR_RESULT_SUCCESS;