cfgt: use dense_integer_mapt to provide instruction -> cfg node mapping

This saves a lot of allocations, memory, and time when the cfg is frequently queried.

Author: smowton

src/goto-instrument/dump_c.cpp

@@ -663,6 +663,9 @@ void dump_ct::cleanup_decl(
 
   tmp.add(goto_programt::make_end_function());
 
+  // goto_program2codet requires valid location numbers:
+  tmp.update();
+
   std::unordered_set<irep_idt> typedef_names;
   for(const auto &td : typedef_map)
     typedef_names.insert(td.first);

src/goto-instrument/goto_instrument_parse_options.cpp

@@ -692,6 +692,10 @@ int goto_instrument_parse_optionst::doit()
       // applied
       restore_returns(goto_model);
 
+      // dump_c (actually goto_program2code) requires valid instruction
+      // location numbers:
+      goto_model.goto_functions.update();
+
       if(cmdline.args.size()==2)
       {
         #ifdef _MSC_VER
@@ -1520,6 +1524,10 @@ void goto_instrument_parse_optionst::instrument_goto_program()
     do_indirect_call_and_rtti_removal();
 
     log.status() << "Performing a reachability slice" << messaget::eom;
+
+    // reachability_slicer requires that the model has unique location numbers:
+    goto_model.goto_functions.update();
+
     if(cmdline.isset("property"))
       reachability_slicer(goto_model, cmdline.get_values("property"));
     else
@@ -1546,7 +1554,11 @@ void goto_instrument_parse_optionst::instrument_goto_program()
     if(cmdline.isset("property"))
       property_slicer(goto_model, cmdline.get_values("property"));
     else
+    {
+      // full_slicer requires that the model has unique location numbers:
+      goto_model.goto_functions.update();
       full_slicer(goto_model);
+    }
   }
 
   // splice option
@@ -1567,6 +1579,9 @@ void goto_instrument_parse_optionst::instrument_goto_program()
   {
     do_indirect_call_and_rtti_removal();
 
+    // reachability_slicer requires that the model has unique location numbers:
+    goto_model.goto_functions.update();
+
     log.status() << "Slicing away initializations of unused global variables"
                  << messaget::eom;
     slice_global_inits(goto_model);
@@ -1595,6 +1610,8 @@ void goto_instrument_parse_optionst::instrument_goto_program()
 
     aggressive_slicer.doit();
 
+    goto_model.goto_functions.update();
+
     log.status() << "Performing a reachability slice" << messaget::eom;
     if(cmdline.isset("property"))
       reachability_slicer(goto_model, cmdline.get_values("property"));

src/goto-programs/cfg.h

@@ -12,8 +12,9 @@ Author: Daniel Kroening, [email protected]
 #ifndef CPROVER_GOTO_PROGRAMS_CFG_H
 #define CPROVER_GOTO_PROGRAMS_CFG_H
 
-#include <util/std_expr.h>
+#include <util/dense_integer_map.h>
 #include <util/graph.h>
+#include <util/std_expr.h>
 
 #include "goto_functions.h"
 
@@ -31,6 +32,29 @@ struct cfg_base_nodet:public graph_nodet<empty_edget>, public T
   I PC;
 };
 
+/// Functor to convert cfg nodes into dense integers, used by \ref cfg_baset.
+/// Default implementation: the identity function.
+template <class T>
+class cfg_instruction_to_dense_integert
+{
+public:
+  std::size_t operator()(T &&t) const
+  {
+    return std::forward<T>(identity_functort{}(t));
+  }
+};
+
+/// GOTO-instruction to location number functor.
+template <>
+class cfg_instruction_to_dense_integert<goto_programt::const_targett>
+{
+public:
+  std::size_t operator()(const goto_programt::const_targett &t) const
+  {
+    return t->location_number;
+  }
+};
+
 /// A multi-procedural control flow graph (CFG) whose nodes store references to
 /// instructions in a GOTO program.
 ///
@@ -69,7 +93,11 @@ class cfg_baset:public grapht< cfg_base_nodet<T, I> >
 
   class entry_mapt final
   {
-    typedef std::map<goto_programt::const_targett, entryt> data_typet;
+    typedef dense_integer_mapt<
+      goto_programt::const_targett,
+      entryt,
+      cfg_instruction_to_dense_integert<goto_programt::const_targett>>
+      data_typet;
     data_typet data;
 
   public:
@@ -114,6 +142,12 @@ class cfg_baset:public grapht< cfg_base_nodet<T, I> >
     {
       return data.at(t);
     }
+
+    template <class Iter>
+    void setup_for_keys(Iter begin, Iter end)
+    {
+      data.setup_for_keys(begin, end);
+    }
   };
   entry_mapt entry_map;
 
@@ -173,12 +207,30 @@ class cfg_baset:public grapht< cfg_base_nodet<T, I> >
   void operator()(
     const goto_functionst &goto_functions)
   {
+    std::vector<goto_programt::const_targett> possible_keys;
+    for(const auto &id_and_function : goto_functions.function_map)
+    {
+      const auto &instructions = id_and_function.second.body.instructions;
+      possible_keys.reserve(
+        possible_keys.size() +
+        std::distance(instructions.begin(), instructions.end()));
+      for(auto it = instructions.begin(); it != instructions.end(); ++it)
+        possible_keys.push_back(it);
+    }
+    entry_map.setup_for_keys(possible_keys.begin(), possible_keys.end());
     compute_edges(goto_functions);
   }
 
   void operator()(P &goto_program)
   {
     goto_functionst goto_functions;
+    std::vector<goto_programt::const_targett> possible_keys;
+    const auto &instructions = goto_program.instructions;
+    possible_keys.reserve(
+      std::distance(instructions.begin(), instructions.end()));
+    for(auto it = instructions.begin(); it != instructions.end(); ++it)
+      possible_keys.push_back(it);
+    entry_map.setup_for_keys(possible_keys.begin(), possible_keys.end());
     compute_edges(goto_functions, goto_program);
   }