// It will be renamed by attaching a number suffix like `@main_{i}`, until there
// are no conflicts. This function is a no-op when no function called @main
// exists.
LogicalResult RenameExistingMainFunction(ModuleOp module_op) {
  SymbolTable symbol_table(module_op);

  auto main_func_op =
      symbol_table.lookup<func::FuncOp>(kImportModelDefaultGraphFuncName);
  if (!main_func_op) {
    return success();