!12983 Fix pynative run graph nullptr

From: @zjun3021
Reviewed-by: @kisnwang,@chujinjin
Signed-off-by: @chujinjin

mindspore/ccsrc/pipeline/pynative/pynative_execute.cc

@@ -2051,6 +2051,7 @@ void PynativeExecutor::MakeNewTopGraph(const string &cell_id, const py::args &ar
     top_cell_info->top_cell_index = cell_graph_list_.size();
     top_cell_index_ = top_cell_info->top_cell_index;
   } else {
+    MS_LOG(DEBUG) << "Get dynamic top cell";
     auto top_cell = GetTopCell(cell_id, true);
     MS_EXCEPTION_IF_NULL(top_cell);
     top_cell_info->top_cell_index = top_cell->top_cell_index;
@@ -2487,7 +2488,7 @@ void PynativeExecutor::GradNetInner(const GradOperationPtr &grad, const py::obje
   const auto &params_changed = CheckGradParamsChanged(cell_id, weights, sens);
   if (!params_changed && !IsFirstGradStep(cell_id) && !CheckRealDynamicCell(cell_id)) {
     UpdateTopCellInfo(cell_id, false);
-    ClearDynamicTopRes(cell_id);
+    ClearDynamicTopRes(cell_id, nullptr);
     MS_LOG(INFO) << "Gradgraph already compiled";
     return;
   }
@@ -2531,10 +2532,11 @@ void PynativeExecutor::GradNetInner(const GradOperationPtr &grad, const py::obje
   ClearUselessRes(df_builder, cell, cell_id);
   UpdateCellGraph(cell, curr_g_, cell_id, false, true);
   UpdateTopCellInfo(cell_id, true);
+  ClearDynamicTopRes(cell_id, df_builder);
   resource->Clean();
 }
 
-void PynativeExecutor::ClearDynamicTopRes(const std::string &cell_id) {
+void PynativeExecutor::ClearDynamicTopRes(const std::string &cell_id, const FuncGraphPtr &df_builder) {
   if (IsTopestGraph(cell_id)) {
     op_index_map_.clear();
   }
@@ -2544,6 +2546,12 @@ void PynativeExecutor::ClearDynamicTopRes(const std::string &cell_id) {
   }
   int same_top_cell_count = 0;
   for (auto it = top_cell_list_.begin(); it != top_cell_list_.end();) {
+    // High order should exclude
+    if (graph_stack_.empty() && df_builder != nullptr && (*it)->df_builder.get() != df_builder.get()) {
+      MS_LOG(DEBUG) << "Delete cell id " << (*it)->cell_id;
+      it = top_cell_list_.erase(it);
+      continue;
+    }
     if ((*it)->cell_id == cell_id) {
       ++same_top_cell_count;
       if (same_top_cell_count > 1) {

mindspore/ccsrc/pipeline/pynative/pynative_execute.h

@@ -270,7 +270,7 @@ class PynativeExecutor : public std::enable_shared_from_this<PynativeExecutor> {
                              const std::string &cell_id, const py::args &args);
   std::string GetGradCellId(bool has_sens, const py::object &cell, const py::args &args, py::object *forward_args,
                             py::object *sens = nullptr);
-  void ClearDynamicTopRes(const std::string &cell_id);
+  void ClearDynamicTopRes(const std::string &cell_id, const FuncGraphPtr &df_builder);
   void GradNetInner(const GradOperationPtr &grad, const py::object &cell, const py::object &weights,
                     const py::args &args);
   std::string GetCellId(const py::object &obj, const py::args &args);