python/binding_c: Add streamsync directive

Extend the functionality of MPIX stream by allowing passing a stream
communication with local gpu stream to regular MPI functions. The
semantics is to run an implicit gpu stream synchronize before the MPI
operation. This is semantically serializing the MPI oepration with the
GPU stream, albeit in a heavy handed way.

maint/local_python/binding_c.py

@@ -1474,6 +1474,16 @@ def dump_function_normal(func):
     # ----
     def dump_body_of_routine():
         do_threadcomm = False
+        if RE.search(r'streamsync', func['extra'], re.IGNORECASE):
+            if '_has_comm' in func:
+                G.out.append("MPIR_Stream *stream = MPIR_stream_comm_get_local_stream(%s_ptr);" % func['_has_comm'])
+            elif '_has_win' in func:
+                G.out.append("MPIR_Stream *stream = MPIR_stream_comm_get_local_stream(%s_ptr->comm_ptr);" % func['_has_win'])
+            else:
+                raise Exception("streamsync not supported in %s" % func['name'])
+            dump_if_open("stream && stream->type == MPIR_STREAM_GPU")
+            G.out.append("MPL_gpu_stream_synchronize(stream->u.gpu_stream);")
+            dump_if_close()
         if RE.search(r'threadcomm', func['extra'], re.IGNORECASE):
             do_threadcomm = True
             G.out.append("#ifdef ENABLE_THREADCOMM")
@@ -1506,6 +1516,7 @@ def dump_body_of_routine():
 
         if do_threadcomm:
             dump_if_close()
+
     # ----
     G.out.append("/* ... body of routine ... */")