Add call-graph topo sort on goto_functionst

This sorts the entire call graph, rather than just the
graph reachable from some particular start point as before.

Author: smowton

src/analyses/call_graph.cpp

@@ -216,3 +216,17 @@ void  inverted_partial_topological_order(
           );
   output.push_back(start_function);
 }
+
+void get_inverted_topological_order(
+  call_grapht const& call_graph,
+  goto_functionst const& functions,
+  std::vector<irep_idt>& output)
+{
+  std::unordered_set<irep_idt,dstring_hash>  processed;
+  for (auto const&  elem : functions.function_map)
+    inverted_partial_topological_order(
+      call_graph,
+      elem.first,
+      processed,
+      output);
+}

src/analyses/call_graph.h

@@ -114,5 +114,9 @@ void  inverted_partial_topological_order(
     std::vector<irep_idt>&  output
     );
 
+void get_inverted_topological_order(
+  call_grapht const& call_graph,
+  goto_functionst const& functions,
+  std::vector<irep_idt>& output);
 
 #endif // CPROVER_ANALYSES_CALL_GRAPH_H