gcc/analyzer/program-state.h

   1 /* Classes for representing the state of interest at a given path of analysis.
   2    Copyright (C) 2019-2020 Free Software Foundation, Inc.
   3    Contributed by David Malcolm <dmalcolm@redhat.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it
   8 under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_ANALYZER_PROGRAM_STATE_H
  22 #define GCC_ANALYZER_PROGRAM_STATE_H
  23
  24 namespace ana {
  25
  26 /* Data shared by all program_state instances.  */
  27
  28 class extrinsic_state
  29 {
  30 public:
  31   extrinsic_state (auto_delete_vec <state_machine> &checkers,
  32                    engine *eng,
  33                    logger *logger = NULL)
  34   : m_checkers (checkers), m_logger (logger), m_engine (eng)
  35   {
  36   }
  37
  38   const state_machine &get_sm (int idx) const
  39   {
  40     return *m_checkers[idx];
  41   }
  42
  43   const char *get_name (int idx) const
  44   {
  45     return m_checkers[idx]->get_name ();
  46   }
  47
  48   unsigned get_num_checkers () const { return m_checkers.length (); }
  49
  50   logger *get_logger () const { return m_logger; }
  51
  52   void dump_to_pp (pretty_printer *pp) const;
  53   void dump_to_file (FILE *outf) const;
  54   void dump () const;
  55
  56   json::object *to_json () const;
  57
  58   engine *get_engine () const { return m_engine; }
  59   region_model_manager *get_model_manager () const;
  60
  61 private:
  62   /* The state machines.  */
  63   auto_delete_vec <state_machine> &m_checkers;
  64
  65   logger *m_logger;
  66   engine *m_engine;
  67 };
  68
  69 /* Map from svalue * to state machine state, also capturing the origin of
  70    each state.  */
  71
  72 class sm_state_map
  73 {
  74 public:
  75   /* An entry in the hash_map.  */
  76   struct entry_t
  77   {
  78     /* Default ctor needed by hash_map::empty.  */
  79     entry_t ()
  80     : m_state (0), m_origin (NULL)
  81     {
  82     }
  83
  84     entry_t (state_machine::state_t state,
  85              const svalue *origin)
  86     : m_state (state), m_origin (origin)
  87     {}
  88
  89     bool operator== (const entry_t &other) const
  90     {
  91       return (m_state == other.m_state
  92               && m_origin == other.m_origin);
  93     }
  94     bool operator!= (const entry_t &other) const
  95     {
  96       return !(*this == other);
  97     }
  98
  99     static int cmp (const entry_t &entry_a, const entry_t &entry_b);
 100
 101     state_machine::state_t m_state;
 102     const svalue *m_origin;
 103   };
 104   typedef hash_map <const svalue *, entry_t> map_t;
 105   typedef map_t::iterator iterator_t;
 106
 107   sm_state_map (const state_machine &sm);
 108
 109   sm_state_map *clone () const;
 110
 111   void print (const region_model *model,
 112               bool simple, bool multiline,
 113               pretty_printer *pp) const;
 114   void dump (bool simple) const;
 115
 116   json::object *to_json () const;
 117
 118   bool is_empty_p () const;
 119
 120   hashval_t hash () const;
 121
 122   bool operator== (const sm_state_map &other) const;
 123   bool operator!= (const sm_state_map &other) const
 124   {
 125     return !(*this == other);
 126   }
 127
 128   state_machine::state_t get_state (const svalue *sval,
 129                                     const extrinsic_state &ext_state) const;
 130   const svalue *get_origin (const svalue *sval,
 131                             const extrinsic_state &ext_state) const;
 132
 133   void set_state (region_model *model,
 134                   const svalue *sval,
 135                   state_machine::state_t state,
 136                   const svalue *origin,
 137                   const extrinsic_state &ext_state);
 138   bool set_state (const equiv_class &ec,
 139                   state_machine::state_t state,
 140                   const svalue *origin,
 141                   const extrinsic_state &ext_state);
 142   bool impl_set_state (const svalue *sval,
 143                        state_machine::state_t state,
 144                        const svalue *origin,
 145                        const extrinsic_state &ext_state);
 146
 147   void set_global_state (state_machine::state_t state);
 148   state_machine::state_t get_global_state () const;
 149
 150   void on_svalue_leak (const svalue *sval,
 151                        impl_region_model_context *ctxt);
 152   void on_liveness_change (const svalue_set &live_svalues,
 153                            const region_model *model,
 154                            impl_region_model_context *ctxt);
 155
 156   void on_unknown_change (const svalue *sval,
 157                           bool is_mutable,
 158                           const extrinsic_state &ext_state);
 159
 160   iterator_t begin () const { return m_map.begin (); }
 161   iterator_t end () const { return m_map.end (); }
 162   size_t elements () const { return m_map.elements (); }
 163
 164   static int cmp (const sm_state_map &smap_a, const sm_state_map &smap_b);
 165
 166   static const svalue *
 167   canonicalize_svalue (const svalue *sval, const extrinsic_state &ext_state);
 168
 169 private:
 170   const state_machine &m_sm;
 171   map_t m_map;
 172   state_machine::state_t m_global_state;
 173 };
 174
 175 /* A class for representing the state of interest at a given path of
 176    analysis.
 177
 178    Currently this is a combination of:
 179    (a) a region_model, giving:
 180       (a.1) a hierarchy of memory regions
 181       (a.2) values for the regions
 182       (a.3) inequalities between values
 183    (b) sm_state_maps per state machine, giving a sparse mapping of
 184        values to states.  */
 185
 186 class program_state
 187 {
 188 public:
 189   program_state (const extrinsic_state &ext_state);
 190   program_state (const program_state &other);
 191   program_state& operator= (const program_state &other);
 192
 193 #if __cplusplus >= 201103
 194   program_state (program_state &&other);
 195 #endif
 196
 197   ~program_state ();
 198
 199   hashval_t hash () const;
 200   bool operator== (const program_state &other) const;
 201   bool operator!= (const program_state &other) const
 202   {
 203     return !(*this == other);
 204   }
 205
 206   void print (const extrinsic_state &ext_state,
 207               pretty_printer *pp) const;
 208
 209   void dump_to_pp (const extrinsic_state &ext_state, bool simple,
 210                    bool multiline, pretty_printer *pp) const;
 211   void dump_to_file (const extrinsic_state &ext_state, bool simple,
 212                      bool multiline, FILE *outf) const;
 213   void dump (const extrinsic_state &ext_state, bool simple) const;
 214
 215   json::object *to_json (const extrinsic_state &ext_state) const;
 216
 217   void push_frame (const extrinsic_state &ext_state, function *fun);
 218   function * get_current_function () const;
 219
 220   bool on_edge (exploded_graph &eg,
 221                 const exploded_node &enode,
 222                 const superedge *succ);
 223
 224   program_state prune_for_point (exploded_graph &eg,
 225                                  const program_point &point,
 226                                  const exploded_node *enode_for_diag) const;
 227
 228   tree get_representative_tree (const svalue *sval) const;
 229
 230   bool can_purge_p (const extrinsic_state &ext_state,
 231                     const svalue *sval)
 232   {
 233     /* Don't purge vars that have non-purgeable sm state, to avoid
 234        generating false "leak" complaints.  */
 235     int i;
 236     sm_state_map *smap;
 237     FOR_EACH_VEC_ELT (m_checker_states, i, smap)
 238       {
 239         const state_machine &sm = ext_state.get_sm (i);
 240         if (!sm.can_purge_p (smap->get_state (sval, ext_state)))
 241           return false;
 242       }
 243     return true;
 244   }
 245
 246   bool can_merge_with_p (const program_state &other,
 247                          const program_point &point,
 248                          program_state *out) const;
 249
 250   void validate (const extrinsic_state &ext_state) const;
 251
 252   static void detect_leaks (const program_state &src_state,
 253                             const program_state &dest_state,
 254                             const svalue *extra_sval,
 255                             const extrinsic_state &ext_state,
 256                             region_model_context *ctxt);
 257
 258   /* TODO: lose the pointer here (const-correctness issues?).  */
 259   region_model *m_region_model;
 260   auto_delete_vec<sm_state_map> m_checker_states;
 261
 262   /* If false, then don't attempt to explore further states along this path.
 263      For use in "handling" lvalues for tree codes we haven't yet
 264      implemented.  */
 265   bool m_valid;
 266 };
 267
 268 /* An abstract base class for use with for_each_state_change.  */
 269
 270 class state_change_visitor
 271 {
 272 public:
 273   virtual ~state_change_visitor () {}
 274
 275   /* Return true for early exit, false to keep iterating.  */
 276   virtual bool on_global_state_change (const state_machine &sm,
 277                                        state_machine::state_t src_sm_val,
 278                                        state_machine::state_t dst_sm_val) = 0;
 279
 280   /* Return true for early exit, false to keep iterating.  */
 281   virtual bool on_state_change (const state_machine &sm,
 282                                 state_machine::state_t src_sm_val,
 283                                 state_machine::state_t dst_sm_val,
 284                                 const svalue *dst_sval,
 285                                 const svalue *dst_origin_sval) = 0;
 286 };
 287
 288 extern bool for_each_state_change (const program_state &src_state,
 289                                     const program_state &dst_state,
 290                                     const extrinsic_state &ext_state,
 291                                     state_change_visitor *visitor);
 292
 293 } // namespace ana
 294
 295 #endif /* GCC_ANALYZER_PROGRAM_STATE_H */