[Frontend][Torch] Check graph inputs match expected (apache#4992)

* [Frontend][Torch] Check graph inputs match expected

* error/warn when missing/unused graph inputs

* Change to use get_graph_input_names

python/tvm/relay/frontend/pytorch.py

@@ -905,6 +905,20 @@ def _report_missing_conversion(op_names):
         msg = "The following operators are not implemented: {}".format(missing)
         raise NotImplementedError(msg)
 
+def _check_input_names(script_module, input_shapes):
+    """ Check the graph inputs match the inputs """
+    ir_inputs = get_graph_input_names(script_module)
+
+    for ir_input in ir_inputs:
+        if ir_input not in input_shapes:
+            msg = "Missing graph input {} in input_shapes".format(ir_input)
+            raise RuntimeError(msg)
+
+    for input_name in input_shapes:
+        if input_name not in ir_inputs:
+            msg = "Unused graph input {} in input_shapes".format(input_name)
+            logging.warning(msg)
+
 
 def _getattr_attr_name(node):
     attribute_names = node.attributeNames()
@@ -1150,6 +1164,7 @@ def from_pytorch(script_module, input_shapes, custom_convert_map=None):
 
     op_names = get_all_op_names(graph)
     _report_missing_conversion(op_names)
+    _check_input_names(script_module, input_shapes)
 
     params = script_module.state_dict()
     input_vars = parse_inputs(graph.inputs(), input_shapes)