// for that remote host. The metadata of the function specifies the input
// values, result values, result devices and the operations to be included in
// the function body.
std::optional<llvm::StringMap<FunctionMetadata>> GetFunctionMetadatas(
    func::FuncOp func_op) {
  llvm::StringMap<FunctionMetadata> metadatas;
  WalkResult result = func_op.getBody().walk([&](Operation *op) {
    std::string op_host = GetHost(op);