Fix bug that renamed subgraph i/o twice (onnx#1478)

* Fix bug that renamed subgraph i/o twice

Signed-off-by: Tom Wildenhain <tomwi@microsoft.com>

* Don't rename tensors in subgraphs at all

Signed-off-by: Tom Wildenhain <tomwi@microsoft.com>

tf2onnx/tfonnx.py

@@ -511,8 +511,6 @@ def rename_tensors_in_nodes(onnx_nodes):
         for func in ordered_func:
             f_inputs_names = [t.name for t in func.inputs]
             f_output_names = [t.name for t in func.outputs]
-            f_inputs_names = rename_tensors_in_list(f_inputs_names)
-            f_output_names = rename_tensors_in_list(f_output_names)
             fg = process_tf_graph(func, continue_on_error, False, target, opset,
                                   custom_op_handlers, custom_rewriter,
                                   extra_opset, shape_override, inputs_as_nchw,
@@ -524,12 +522,13 @@ def rename_tensors_in_nodes(onnx_nodes):
 
     check_io(input_names, output_names, output_shapes)
 
-    rename_tensors_in_nodes(onnx_nodes)
-    input_names = rename_tensors_in_list(input_names)
-    output_names = rename_tensors_in_list(output_names)
-    output_shapes = rename_tensors_in_dict(output_shapes)
-    dtypes = rename_tensors_in_dict(dtypes)
-    inputs_as_nchw = rename_tensors_in_list(inputs_as_nchw)
+    if not is_subgraph:
+        rename_tensors_in_nodes(onnx_nodes)
+        input_names = rename_tensors_in_list(input_names)
+        output_names = rename_tensors_in_list(output_names)
+        output_shapes = rename_tensors_in_dict(output_shapes)
+        dtypes = rename_tensors_in_dict(dtypes)
+        inputs_as_nchw = rename_tensors_in_list(inputs_as_nchw)
     g = Graph(onnx_nodes, output_shapes, dtypes, target, opset, extra_opset, input_names, output_names, is_subgraph)
     g = process_parsed_graph(g, custom_op_handlers, inputs_as_nchw, continue_on_error, custom_rewriter, target,
                              output_names, initialized_tables, outputs_to_values, outputs_to_dtypes, op_cnt, attr_cnt)