std::string* filepath, llvm::StringRef dirname) {
  std::string dir;
  if (!dirname.empty())
    dir = std::string(dirname);
  else
    dir = GetDumpDirFromEnvVar();

  if (dir.empty()) {
    return Status(absl::StatusCode::kInvalidArgument,
                  "(TF_DUMP_GRAPH_PREFIX not specified)");
  }

  if (dir == kCrashReproducerStdErr) {

// Default is reading from TF_DUMP_GRAPH_PREFIX, and if the string is 'sponge'
// read from TEST_UNDECLARED_OUTPUTS_DIR. Returns nullptr if the directory
// cannot be determined and generates a warning message.
std::string GetDumpDirFromEnvVar();

// Dumps a raw string to a file and returns the file name used.
//
// This will create a file name via prefixing `name` with the value of the
// TF_DUMP_GRAPH_PREFIX environment variable if `dirname` is empty and

// Dumps the MLIR module to disk.
// This require the TF_DUMP_GRAPH_PREFIX to be set to a path that exist (or can
// be created).
static void DumpModule(mlir::ModuleOp module, std::string file_prefix) {
  std::string prefix = GetDumpDirFromEnvVar();
  if (prefix.empty()) return;

  auto* env = tensorflow::Env::Default();
  auto status = env->RecursivelyCreateDir(prefix);
  if (!status.ok()) {
    LOG(WARNING) << "cannot create directory '" << prefix