if (opr) {
      producer = opr.getOwner();
      port = {opr.getResultNumber()};
    } else {
      producer = mlir::cast<BlockArgument>(v);
      port = {0};
    }
  }
  ValuePort(PointerUnion<Operation*, BlockArgument> producer,
            SmallVector<unsigned int, 2> port)
      : producer(producer), port(port) {}

  raw_ostream& print(raw_ostream& os) const {

  // have associated tensor and buffer. Build FlatBuffer tensor and buffer for
  // other functions.
  for (unsigned i = 0, e = bb.getNumArguments(); i < e; ++i) {
    mlir::BlockArgument arg = bb.getArgument(i);
    std::string tensor_name;
    if (has_input_attr)
      tensor_name = std::string(name_mapper_.GetUniqueName(arg));
    if (tensor_name.empty()) tensor_name = absl::StrCat("arg", i);