+ // that depend on it (whenever possible). Returns the phase that has <output>
+ // as the last effect. Also pushes all phases in order onto <phases>.
+ Phase *construct_phase(Node *output, std::map<Node *, Phase *> *completed_effects);
+
+ // Output the current graph to the given file in a Graphviz-compatible format;
+ // only useful for debugging.
+ void output_dot(const char *filename);
+ std::vector<std::string> get_labels_for_edge(const Node *from, const Node *to);
+ void output_dot_edge(FILE *fp,
+ const std::string &from_node_id,
+ const std::string &to_node_id,
+ const std::vector<std::string> &labels);
+
+ // Some of the graph algorithms assume that the nodes array is sorted
+ // topologically (inputs are always before outputs), but some operations
+ // (like graph rewriting) can change that. This function restores that order.
+ void sort_all_nodes_topologically();
+
+ // Do the actual topological sort. <nodes> must be a connected, acyclic subgraph;
+ // links that go to nodes not in the set will be ignored.
+ std::vector<Node *> topological_sort(const std::vector<Node *> &nodes);
+
+ // Utility function used by topological_sort() to do a depth-first search.
+ // The reason why we store nodes left to visit instead of a more conventional
+ // list of nodes to visit is that we want to be able to limit ourselves to
+ // a subgraph instead of all nodes. The set thus serves a dual purpose.
+ void topological_sort_visit_node(Node *node, std::set<Node *> *nodes_left_to_visit, std::vector<Node *> *sorted_list);