mlir::SymbolTable::setSymbolName(func, new_sym_name);
  }

  // Copy all functions used by this signature to the final MLIR module.
  for (auto func : sub_module.getOps<mlir::func::FuncOp>()) {
    absl::MutexLock l(&symbol_table_mu_);
    // The insert here is a NO-OP if the function already exists.
    symbol_table_.insert(func.clone());
  }

  return absl::OkStatus();
}