call graph helper interface to "get shortest path" function of grapht

gets list of functions on shortest path between function src and function dest.

Author: polgreen

src/analyses/call_graph_helpers.cpp

@@ -101,3 +101,25 @@ std::set<irep_idt> get_functions_reachable_within_n_steps(
   return get_functions_reachable_within_n_steps(
     graph, start_functions, n, forwards);
 }
+
+std::set<irep_idt> get_shortest_function_path(
+  const call_grapht::directed_grapht &graph,
+  const irep_idt &src,
+  const irep_idt &dest)
+{
+  std::set<irep_idt> result;
+  std::size_t start_node = *graph.get_node_index(src);
+  std::size_t dest_node = *graph.get_node_index(dest);
+
+  PRECONDITION(
+    start_node != optionalt<std::size_t>() &&
+    dest_node != optionalt<std::size_t>());
+
+  std::list<std::size_t> path;
+  graph.shortest_path(start_node, dest_node, path);
+
+  for(const auto &n : path)
+    result.insert(graph[n].function);
+
+  return result;
+}

src/analyses/call_graph_helpers.h

@@ -49,6 +49,15 @@ std::set<irep_idt> get_reachable_functions(
 std::set<irep_idt> get_reaching_functions(
   const call_grapht::directed_grapht &graph, const irep_idt &function);
 
+/// Get list of functions on the shortest path between two functions
+/// \param graph: call graph
+/// \param src: function to start from
+/// \param dest: function to reach
+std::set<irep_idt> get_shortest_function_path(
+  const call_grapht::directed_grapht &graph,
+  const irep_idt &src,
+  const irep_idt &dest);
+
 /// Get either callers or callees reachable from a given
 /// list of functions within N steps
 /// \param graph: call graph