// If 'reuse_existing_functions' is set, use an existing function with the
  // same name, if any.
  // If 'rewrite_subgraph_fn' is set, it is applied to each subgraph before
  // function conversion.
  Status BuildFunctionDefs(const RewriteSubgraphFn& rewrite_subgraph_fn,
                           bool reuse_existing_functions,
                           FunctionLibraryDefinition* library);

// 'group_attribute' must be a string valued-attribute that names the new
// functions to introduce.
//
// If 'rewrite_subgraph_fn' is set, it is applied to each subgraph before
// function conversion.
//
// If 'reuse_existing_functions' is set, use an existing function with the
// same name, if any.
//
// TODO(phawkins): currently, some information in control edges
// is not preserved. Suppose you have A and B in the main

  auto output = std::make_unique<Graph>((*graph)->op_registry());
  TF_RETURN_WITH_CONTEXT_IF_ERROR(
      EncapsulateSubgraphsInFunctions(
          kXlaClusterIdAttr, **graph, RewriteSubgraph,
          /*reuse_existing_functions=*/true, &output, flib_def),
      "EncapsulateXlaComputationsPass failed");
  graph->swap(output);
  return absl::OkStatus();
}

/*static*/ Status EncapsulateXlaComputationsPass::BuildXlaLaunchOps(

  std::unique_ptr<Graph> graph_out;
  s = EncapsulateSubgraphsInFunctions("_encapsulate", *graph,
                                      /*rewrite_subgraph_fn=*/{},
                                      /*reuse_existing_functions=*/false,
                                      &graph_out, lib_def.get());
  if (!s.ok()) return s;

  std::unordered_map<string, XlaClusterInfo> clusters;
  for (const auto& func : encapsulated_functions) {

        new_func_name);
    TF_RETURN_IF_ERROR(EncapsulateSubgraphsInFunctions(
        outside_compilation_attr_name, *fbody->graph, *rewrite_fn,
        /*reuse_existing_functions=*/true, &graph_out, fld));

    // Replace outside_compilation function nodes with HostCompute ops.
    std::vector<Node*> outside_compilation_nodes;
    for (Node* n : graph_out->nodes()) {