Add call graph helpers

These translate from function name to node ID and back, thus giving
more concise ways of running very simple graph algorithms over the
call graph.

Author: smowton

src/analyses/Makefile

@@ -1,5 +1,6 @@
 SRC = ai.cpp \
       call_graph.cpp \
+      call_graph_helpers.cpp \
       constant_propagator.cpp \
       custom_bitvector_analysis.cpp \
       dependence_graph.cpp \

src/analyses/call_graph_helpers.cpp

@@ -0,0 +1,72 @@
+/*******************************************************************\
+
+Module: Function Call Graph Helpers
+
+Author: Chris Smowton, [email protected]
+
+\*******************************************************************/
+
+/// \file
+/// Function Call Graph Helpers
+
+#include "call_graph_helpers.h"
+
+/// Get either callers or callees of a given function
+/// \param graph: call graph
+/// \param function: function to query
+/// \param forwards: if true, get callees; otherwise get callers.
+static std::set<irep_idt> get_neighbours(
+  const call_grapht::directed_grapht &graph,
+  const irep_idt &function,
+  bool forwards)
+{
+  std::set<irep_idt> result;
+  const auto &fnode = graph[*(graph.get_node_index(function))];
+  const auto &neighbours = forwards ? fnode.out : fnode.in;
+  for(const auto &succ_edge : neighbours)
+    result.insert(graph[succ_edge.first].function);
+  return result;
+}
+
+std::set<irep_idt> get_callees(
+  const call_grapht::directed_grapht &graph, const irep_idt &function)
+{
+  return get_neighbours(graph, function, true);
+}
+
+std::set<irep_idt> get_callers(
+  const call_grapht::directed_grapht &graph, const irep_idt &function)
+{
+  return get_neighbours(graph, function, false);
+}
+
+/// Get either reachable functions or functions that can reach a given function.
+/// In both cases the query function itself is included.
+/// \param graph: call graph
+/// \param function: function to query
+/// \param forwards: if true, get reachable functions; otherwise get functions
+///   that can reach the given function.
+static std::set<irep_idt> get_connected_functions(
+  const call_grapht::directed_grapht &graph,
+  const irep_idt &function,
+  bool forwards)
+{
+  std::vector<call_grapht::directed_grapht::node_indext> connected_nodes =
+    graph.get_reachable(*(graph.get_node_index(function)), forwards);
+  std::set<irep_idt> result;
+  for(const auto i : connected_nodes)
+    result.insert(graph[i].function);
+  return result;
+}
+
+std::set<irep_idt> get_reachable_functions(
+  const call_grapht::directed_grapht &graph, const irep_idt &function)
+{
+  return get_connected_functions(graph, function, true);
+}
+
+std::set<irep_idt> get_reaching_functions(
+  const call_grapht::directed_grapht &graph, const irep_idt &function)
+{
+  return get_connected_functions(graph, function, false);
+}

src/analyses/call_graph_helpers.h

@@ -0,0 +1,52 @@
+/*******************************************************************\
+
+Module: Function Call Graph Helpers
+
+Author: Chris Smowton, [email protected]
+
+\*******************************************************************/
+
+/// \file
+/// Function Call Graph Helpers
+
+#ifndef CPROVER_ANALYSES_CALL_GRAPH_HELPERS_H
+#define CPROVER_ANALYSES_CALL_GRAPH_HELPERS_H
+
+#include "call_graph.h"
+
+// These are convenience functions for working with the directed graph
+// representation of a call graph, obtained via
+// `call_grapht::get_directed_graph`. Usually function names must be mapped
+// to and from node indices, as in `graph.get_node_index("f")`, or
+// `graph[node_index].function`; these helpers include the translation for
+// convenience.
+
+/// Get functions directly callable from a given function
+/// \param graph: call graph
+/// \param function: function to query
+/// \return set of called functions
+std::set<irep_idt> get_callees(
+  const call_grapht::directed_grapht &graph, const irep_idt &function);
+
+/// Get functions that call a given function
+/// \param graph: call graph
+/// \param function: function to query
+/// \return set of caller functions
+std::set<irep_idt> get_callers(
+  const call_grapht::directed_grapht &graph, const irep_idt &function);
+
+/// Get functions reachable from a given function
+/// \param graph: call graph
+/// \param function: function to query
+/// \return set of reachable functions, including `function`
+std::set<irep_idt> get_reachable_functions(
+  const call_grapht::directed_grapht &graph, const irep_idt &function);
+
+/// Get functions that can reach a given function
+/// \param graph: call graph
+/// \param function: function to query
+/// \return set of functions that can reach the target, including `function`
+std::set<irep_idt> get_reaching_functions(
+  const call_grapht::directed_grapht &graph, const irep_idt &function);
+
+#endif