importer supports block arg

oneflow/ir/oneflow-translate/lib/OneFlow/Importer.cpp

@@ -439,6 +439,9 @@ LogicalResult ConvertUserOpInputs(Operation* op, oneflow::UserOpAdaptor& user_op
                   .str();
           *((*user_conf->mutable_input())[input_key].mutable_s()->Add()) = output_lbn_in_source_op;
           input_idx += 1;
+        } else if (auto arg = op->getOperand(input_idx).dyn_cast<mlir::BlockArgument>()) {
+          *((*user_conf->mutable_input())[input_key].mutable_s()->Add()) =
+              "arg/" + std::to_string(arg.getArgNumber());
         } else {
           op->emitError() << "fail to convert MLIR result to protobuf, name: " + op_name;
           op->dump();