!2873 Adjust layer number of outputs of empty graph

Merge pull request !2873 from zhoufeng/xiu-ba-ge

mindspore/ccsrc/session/ascend_session.cc

@@ -51,6 +51,7 @@
 namespace mindspore {
 namespace session {
 const size_t kInvalidIndex = SIZE_MAX;
+constexpr size_t kReturnDataIndex = 1;
 namespace {
 void DumpGraphExeOrder(const std::vector<CNodePtr> &execution_order, const std::string &tag = "") {
   MS_LOG(INFO) << "Dump execution_order size " << execution_order.size();
@@ -288,6 +289,19 @@ static void RecurseToUpdateCallRealInput(NotNull<KernelGraphPtr> graph,
   // this action should from bottom to top
   graph->UpdateCallRealInput();
 }
+
+void InsertMakeTupleForEmptyGraph(NotNull<KernelGraphPtr> graph) {
+  auto return_node = graph->get_return();
+  MS_EXCEPTION_IF_NULL(return_node);
+  auto origin_output = return_node->input(kReturnDataIndex);
+  MS_EXCEPTION_IF_NULL(origin_output);
+  std::vector<AnfNodePtr> make_tuple_input{
+    std::make_shared<ValueNode>(std::make_shared<Primitive>(prim::kPrimMakeTuple->name())), origin_output};
+  auto new_outputs = graph->NewCNode(make_tuple_input);
+  MS_EXCEPTION_IF_NULL(new_outputs);
+  new_outputs->set_abstract(origin_output->abstract());
+  return_node->set_input(kReturnDataIndex, new_outputs);
+}
 }  // namespace
 
 GraphId AscendSession::CompileGraph(const AnfNodePtrList &lst, const AnfNodePtrList &outputs) {
@@ -305,8 +319,10 @@ GraphId AscendSession::CompileGraph(NotNull<FuncGraphPtr> func_graph) {
   auto root_graph = ConstructKernelGraph(func_graph, &all_graphs);
   BackendOptimization(all_graphs);
   // empty graph dont entry to backend
-  if (root_graph->execution_order().empty()) {
+  if (std::none_of(root_graph->execution_order().begin(), root_graph->execution_order().end(),
+                   [](const CNodePtr &cnode) -> bool { return AnfAlgo::IsRealKernel(cnode); })) {
     MS_LOG(INFO) << root_graph->ToString() << " is empty graph.";
+    InsertMakeTupleForEmptyGraph(NOT_NULL(root_graph));
     root_graph->set_executable(false);
     InitRuntimeResource();
     return root_graph->graph_id();
@@ -1027,7 +1043,7 @@ void AscendSession::InsertSwitchToGraph(GraphId condition_graph_id, GraphId true
   // append switch at the end of condition graph
   auto return_node = condition_graph->get_return();
   MS_EXCEPTION_IF_NULL(return_node);
-  InsertControlDependToGraph(condition_graph_id, return_node->input(1), switch_node);
+  InsertControlDependToGraph(condition_graph_id, return_node->input(kReturnDataIndex), switch_node);
   MS_LOG(INFO) << "Finish!";
 }
 
@@ -1477,7 +1493,7 @@ void AscendSession::InsertStreamActiveToGraph(GraphId graph_id, uint32_t actived
   // append the active node at the end of from graph
   auto return_node = from_graph->get_return();
   MS_EXCEPTION_IF_NULL(return_node);
-  InsertControlDependToGraph(graph_id, return_node->input(1), active_node);
+  InsertControlDependToGraph(graph_id, return_node->input(kReturnDataIndex), active_node);
 }
 
 void AscendSession::InsertDependToGraph(GraphId graph_id, const AnfNodePtr &attch_node) {