std::string DebugUtil::GetTensorsGraphInfo()

in torch_xla/csrc/debug_util.cpp [54:112]
58 lines of code
13 McCabe index (conditional complexity)

std::string DebugUtil::GetTensorsGraphInfo(absl::Span<const XLATensor> tensors,
                                           const std::vector<size_t>* indices,
                                           GraphFormat format) {
  std::vector<const ir::Node*> root_nodes;
  std::vector<ir::Value> root_values;
  std::vector<torch::lazy::hash_t> root_hashes;
  xla::util::Unique<Device> unique_device;
  if (indices != nullptr) {
    for (auto index : *indices) {
      const XLATensor& tensor = tensors[index];
      ir::Value ir_value = tensor.CurrentIrValue();
      if (ir_value) {
        root_nodes.push_back(ir_value.node.get());
        root_hashes.push_back(ir_value.hash());
        root_values.push_back(std::move(ir_value));
        unique_device.set(tensor.GetDevice());
      }
    }
  } else {
    for (auto& tensor : tensors) {
      ir::Value ir_value = tensor.CurrentIrValue();
      if (ir_value) {
        root_nodes.push_back(ir_value.node.get());
        root_hashes.push_back(ir_value.hash());
        root_values.push_back(std::move(ir_value));
        unique_device.set(tensor.GetDevice());
      }
    }
  }
  std::stringstream ss;
  std::vector<SourceLocation> frames = GetPythonFrames();
  ss << "TensorsGraphInfo:\n";
  for (auto& location : frames) {
    ss << "  " << location.function << " (" << location.file << ":"
       << location.line << ")\n";
  }
  ss << "\nHashes: (";
  for (size_t i = 0; i < root_hashes.size(); ++i) {
    if (i > 0) {
      ss << ", ";
    }
    ss << torch::lazy::HashToString(root_hashes[i]);
  }
  ss << ")\n";

  std::string graph_str;
  if (format == GraphFormat::kText) {
    graph_str = ir::DumpUtil::ToText(root_nodes);
  } else if (format == GraphFormat::kDot) {
    graph_str = ir::DumpUtil::ToDot(root_nodes);
  } else if (format == GraphFormat::kHlo) {
    graph_str = ir::DumpUtil::ToHlo(
        root_values, unique_device ? *unique_device : GetCurrentDevice());
  } else {
    XLA_ERROR() << "Invalid graph format: " << format;
  }
  ss << "\n## BEGIN_GRAPH\n" << graph_str << "\n## END_GRAPH\n\n";
  return ss.str();
}