absl::StatusOr<mlir::FunctionType> InferLibFunctionType(
      const FunctionBody& fbody);

  // Extracts arg and ret nodes from FunctionBody.
  void GetArgsAndRetsFromFunctionBody(
      const FunctionBody& fbody,
      absl::InlinedVector<OutputTensor, 4>* arg_nodes,
      absl::InlinedVector<OutputTensor, 4>* ret_nodes,
      absl::InlinedVector<Node*, 4>* control_ret_nodes);