gcc/analyzer/region-model.h

   1 /* Classes for modeling the state of memory.
   2    Copyright (C) 2019-2022 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_REGION_MODEL_H
  22 #define GCC_ANALYZER_REGION_MODEL_H
  23
  24 /* Implementation of the region-based ternary model described in:
  25      "A Memory Model for Static Analysis of C Programs"
  26       (Zhongxing Xu, Ted Kremenek, and Jian Zhang)
  27      http://lcs.ios.ac.cn/~xuzb/canalyze/memmodel.pdf  */
  28
  29 #include "sbitmap.h"
  30 #include "selftest.h"
  31 #include "analyzer/svalue.h"
  32 #include "analyzer/region.h"
  33 #include "analyzer/known-function-manager.h"
  34 #include "analyzer/region-model-manager.h"
  35 #include "analyzer/pending-diagnostic.h"
  36
  37 using namespace ana;
  38
  39 namespace inchash
  40 {
  41   extern void add_path_var (path_var pv, hash &hstate);
  42 } // namespace inchash
  43
  44 namespace ana {
  45
  46 template <typename T>
  47 class one_way_id_map
  48 {
  49  public:
  50   one_way_id_map (int num_ids);
  51   void put (T src, T dst);
  52   T get_dst_for_src (T src) const;
  53   void dump_to_pp (pretty_printer *pp) const;
  54   void dump () const;
  55   void update (T *) const;
  56
  57  private:
  58   auto_vec<T> m_src_to_dst;
  59  };
  60
  61 /* class one_way_id_map.  */
  62
  63 /* one_way_id_map's ctor, which populates the map with dummy null values.  */
  64
  65 template <typename T>
  66 inline one_way_id_map<T>::one_way_id_map (int num_svalues)
  67 : m_src_to_dst (num_svalues)
  68 {
  69   for (int i = 0; i < num_svalues; i++)
  70     m_src_to_dst.quick_push (T::null ());
  71 }
  72
  73 /* Record that SRC is to be mapped to DST.  */
  74
  75 template <typename T>
  76 inline void
  77 one_way_id_map<T>::put (T src, T dst)
  78 {
  79   m_src_to_dst[src.as_int ()] = dst;
  80 }
  81
  82 /* Get the new value for SRC within the map.  */
  83
  84 template <typename T>
  85 inline T
  86 one_way_id_map<T>::get_dst_for_src (T src) const
  87 {
  88   if (src.null_p ())
  89     return src;
  90   return m_src_to_dst[src.as_int ()];
  91 }
  92
  93 /* Dump this map to PP.  */
  94
  95 template <typename T>
  96 inline void
  97 one_way_id_map<T>::dump_to_pp (pretty_printer *pp) const
  98 {
  99   pp_string (pp, "src to dst: {");
 100   unsigned i;
 101   T *dst;
 102   FOR_EACH_VEC_ELT (m_src_to_dst, i, dst)
 103     {
 104       if (i > 0)
 105         pp_string (pp, ", ");
 106       T src (T::from_int (i));
 107       src.print (pp);
 108       pp_string (pp, " -> ");
 109       dst->print (pp);
 110     }
 111   pp_string (pp, "}");
 112   pp_newline (pp);
 113 }
 114
 115 /* Dump this map to stderr.  */
 116
 117 template <typename T>
 118 DEBUG_FUNCTION inline void
 119 one_way_id_map<T>::dump () const
 120 {
 121   pretty_printer pp;
 122   pp.buffer->stream = stderr;
 123   dump_to_pp (&pp);
 124   pp_flush (&pp);
 125 }
 126
 127 /* Update *ID from the old value to its new value in this map.  */
 128
 129 template <typename T>
 130 inline void
 131 one_way_id_map<T>::update (T *id) const
 132 {
 133   *id = get_dst_for_src (*id);
 134 }
 135
 136 /* A mapping from region to svalue for use when tracking state.  */
 137
 138 class region_to_value_map
 139 {
 140 public:
 141   typedef hash_map<const region *, const svalue *> hash_map_t;
 142   typedef hash_map_t::iterator iterator;
 143
 144   region_to_value_map () : m_hash_map () {}
 145   region_to_value_map (const region_to_value_map &other)
 146   : m_hash_map (other.m_hash_map) {}
 147   region_to_value_map &operator= (const region_to_value_map &other);
 148
 149   bool operator== (const region_to_value_map &other) const;
 150   bool operator!= (const region_to_value_map &other) const
 151   {
 152     return !(*this == other);
 153   }
 154
 155   iterator begin () const { return m_hash_map.begin (); }
 156   iterator end () const { return m_hash_map.end (); }
 157
 158   const svalue * const *get (const region *reg) const
 159   {
 160     return const_cast <hash_map_t &> (m_hash_map).get (reg);
 161   }
 162   void put (const region *reg, const svalue *sval)
 163   {
 164     m_hash_map.put (reg, sval);
 165   }
 166   void remove (const region *reg)
 167   {
 168     m_hash_map.remove (reg);
 169   }
 170
 171   bool is_empty () const { return m_hash_map.is_empty (); }
 172
 173   void dump_to_pp (pretty_printer *pp, bool simple, bool multiline) const;
 174   void dump (bool simple) const;
 175
 176   bool can_merge_with_p (const region_to_value_map &other,
 177                          region_to_value_map *out) const;
 178
 179   void purge_state_involving (const svalue *sval);
 180
 181 private:
 182   hash_map_t m_hash_map;
 183 };
 184
 185 /* Various operations delete information from a region_model.
 186
 187    This struct tracks how many of each kind of entity were purged (e.g.
 188    for selftests, and for debugging).  */
 189
 190 struct purge_stats
 191 {
 192   purge_stats ()
 193   : m_num_svalues (0),
 194     m_num_regions (0),
 195     m_num_equiv_classes (0),
 196     m_num_constraints (0),
 197     m_num_bounded_ranges_constraints (0),
 198     m_num_client_items (0)
 199   {}
 200
 201   int m_num_svalues;
 202   int m_num_regions;
 203   int m_num_equiv_classes;
 204   int m_num_constraints;
 205   int m_num_bounded_ranges_constraints;
 206   int m_num_client_items;
 207 };
 208
 209 /* A base class for visiting regions and svalues, with do-nothing
 210    base implementations of the per-subclass vfuncs.  */
 211
 212 class visitor
 213 {
 214 public:
 215   virtual void visit_region_svalue (const region_svalue *) {}
 216   virtual void visit_constant_svalue (const constant_svalue *) {}
 217   virtual void visit_unknown_svalue (const unknown_svalue *) {}
 218   virtual void visit_poisoned_svalue (const poisoned_svalue *) {}
 219   virtual void visit_setjmp_svalue (const setjmp_svalue *) {}
 220   virtual void visit_initial_svalue (const initial_svalue *) {}
 221   virtual void visit_unaryop_svalue (const unaryop_svalue *) {}
 222   virtual void visit_binop_svalue (const binop_svalue *) {}
 223   virtual void visit_sub_svalue (const sub_svalue *) {}
 224   virtual void visit_repeated_svalue (const repeated_svalue *) {}
 225   virtual void visit_bits_within_svalue (const bits_within_svalue *) {}
 226   virtual void visit_unmergeable_svalue (const unmergeable_svalue *) {}
 227   virtual void visit_placeholder_svalue (const placeholder_svalue *) {}
 228   virtual void visit_widening_svalue (const widening_svalue *) {}
 229   virtual void visit_compound_svalue (const compound_svalue *) {}
 230   virtual void visit_conjured_svalue (const conjured_svalue *) {}
 231   virtual void visit_asm_output_svalue (const asm_output_svalue *) {}
 232   virtual void visit_const_fn_result_svalue (const const_fn_result_svalue *) {}
 233
 234   virtual void visit_region (const region *) {}
 235 };
 236
 237 struct append_regions_cb_data;
 238
 239 /* A region_model encapsulates a representation of the state of memory, with
 240    a tree of regions, along with their associated values.
 241    The representation is graph-like because values can be pointers to
 242    regions.
 243    It also stores:
 244    - a constraint_manager, capturing relationships between the values, and
 245    - dynamic extents, mapping dynamically-allocated regions to svalues (their
 246    capacities).  */
 247
 248 class region_model
 249 {
 250  public:
 251   typedef region_to_value_map dynamic_extents_t;
 252
 253   region_model (region_model_manager *mgr);
 254   region_model (const region_model &other);
 255   ~region_model ();
 256   region_model &operator= (const region_model &other);
 257
 258   bool operator== (const region_model &other) const;
 259   bool operator!= (const region_model &other) const
 260   {
 261     return !(*this == other);
 262   }
 263
 264   hashval_t hash () const;
 265
 266   void print (pretty_printer *pp) const;
 267
 268   void dump_to_pp (pretty_printer *pp, bool simple, bool multiline) const;
 269   void dump (FILE *fp, bool simple, bool multiline) const;
 270   void dump (bool simple) const;
 271
 272   void debug () const;
 273
 274   void validate () const;
 275
 276   void canonicalize ();
 277   bool canonicalized_p () const;
 278
 279   void
 280   on_stmt_pre (const gimple *stmt,
 281                bool *out_unknown_side_effects,
 282                region_model_context *ctxt);
 283
 284   void on_assignment (const gassign *stmt, region_model_context *ctxt);
 285   const svalue *get_gassign_result (const gassign *assign,
 286                                     region_model_context *ctxt);
 287   void on_asm_stmt (const gasm *asm_stmt, region_model_context *ctxt);
 288   bool on_call_pre (const gcall *stmt, region_model_context *ctxt);
 289   void on_call_post (const gcall *stmt,
 290                      bool unknown_side_effects,
 291                      region_model_context *ctxt);
 292
 293   void purge_state_involving (const svalue *sval, region_model_context *ctxt);
 294
 295   void impl_deallocation_call (const call_details &cd);
 296
 297   const svalue *maybe_get_copy_bounds (const region *src_reg,
 298                                        const svalue *num_bytes_sval);
 299   void update_for_int_cst_return (const call_details &cd,
 300                                   int retval,
 301                                   bool unmergeable);
 302   void update_for_zero_return (const call_details &cd,
 303                                bool unmergeable);
 304   void update_for_nonzero_return (const call_details &cd);
 305
 306   void handle_unrecognized_call (const gcall *call,
 307                                  region_model_context *ctxt);
 308   void get_reachable_svalues (svalue_set *out,
 309                               const svalue *extra_sval,
 310                               const uncertainty_t *uncertainty);
 311
 312   void on_return (const greturn *stmt, region_model_context *ctxt);
 313   void on_setjmp (const gcall *stmt, const exploded_node *enode,
 314                   region_model_context *ctxt);
 315   void on_longjmp (const gcall *longjmp_call, const gcall *setjmp_call,
 316                    int setjmp_stack_depth, region_model_context *ctxt);
 317
 318   void update_for_phis (const supernode *snode,
 319                         const cfg_superedge *last_cfg_superedge,
 320                         region_model_context *ctxt);
 321
 322   void handle_phi (const gphi *phi, tree lhs, tree rhs,
 323                    const region_model &old_state,
 324                    region_model_context *ctxt);
 325
 326   bool maybe_update_for_edge (const superedge &edge,
 327                               const gimple *last_stmt,
 328                               region_model_context *ctxt,
 329                               rejected_constraint **out);
 330
 331   void update_for_gcall (const gcall *call_stmt,
 332                          region_model_context *ctxt,
 333                          function *callee = NULL);
 334
 335   void update_for_return_gcall (const gcall *call_stmt,
 336                                 region_model_context *ctxt);
 337
 338   const region *push_frame (function *fun, const vec<const svalue *> *arg_sids,
 339                             region_model_context *ctxt);
 340   const frame_region *get_current_frame () const { return m_current_frame; }
 341   function * get_current_function () const;
 342   void pop_frame (tree result_lvalue,
 343                   const svalue **out_result,
 344                   region_model_context *ctxt);
 345   int get_stack_depth () const;
 346   const frame_region *get_frame_at_index (int index) const;
 347
 348   const region *get_lvalue (path_var pv, region_model_context *ctxt) const;
 349   const region *get_lvalue (tree expr, region_model_context *ctxt) const;
 350   const svalue *get_rvalue (path_var pv, region_model_context *ctxt) const;
 351   const svalue *get_rvalue (tree expr, region_model_context *ctxt) const;
 352
 353   const region *deref_rvalue (const svalue *ptr_sval, tree ptr_tree,
 354                                region_model_context *ctxt) const;
 355
 356   const svalue *get_rvalue_for_bits (tree type,
 357                                      const region *reg,
 358                                      const bit_range &bits,
 359                                      region_model_context *ctxt) const;
 360
 361   void set_value (const region *lhs_reg, const svalue *rhs_sval,
 362                   region_model_context *ctxt);
 363   void set_value (tree lhs, tree rhs, region_model_context *ctxt);
 364   void clobber_region (const region *reg);
 365   void purge_region (const region *reg);
 366   void fill_region (const region *reg, const svalue *sval);
 367   void zero_fill_region (const region *reg);
 368   void mark_region_as_unknown (const region *reg, uncertainty_t *uncertainty);
 369
 370   tristate eval_condition (const svalue *lhs,
 371                            enum tree_code op,
 372                            const svalue *rhs) const;
 373   tristate compare_initial_and_pointer (const initial_svalue *init,
 374                                         const region_svalue *ptr) const;
 375   tristate symbolic_greater_than (const binop_svalue *a,
 376                                   const svalue *b) const;
 377   tristate structural_equality (const svalue *a, const svalue *b) const;
 378   tristate eval_condition (tree lhs,
 379                            enum tree_code op,
 380                            tree rhs,
 381                            region_model_context *ctxt) const;
 382   bool add_constraint (tree lhs, enum tree_code op, tree rhs,
 383                        region_model_context *ctxt);
 384   bool add_constraint (tree lhs, enum tree_code op, tree rhs,
 385                        region_model_context *ctxt,
 386                        rejected_constraint **out);
 387
 388   const region *
 389   get_or_create_region_for_heap_alloc (const svalue *size_in_bytes,
 390                                        region_model_context *ctxt);
 391   const region *create_region_for_alloca (const svalue *size_in_bytes,
 392                                           region_model_context *ctxt);
 393   void get_referenced_base_regions (auto_sbitmap &out_ids) const;
 394
 395   tree get_representative_tree (const svalue *sval) const;
 396   tree get_representative_tree (const region *reg) const;
 397   path_var
 398   get_representative_path_var (const svalue *sval,
 399                                svalue_set *visited) const;
 400   path_var
 401   get_representative_path_var (const region *reg,
 402                                svalue_set *visited) const;
 403
 404   /* For selftests.  */
 405   constraint_manager *get_constraints ()
 406   {
 407     return m_constraints;
 408   }
 409
 410   store *get_store () { return &m_store; }
 411   const store *get_store () const { return &m_store; }
 412
 413   const dynamic_extents_t &
 414   get_dynamic_extents () const
 415   {
 416     return m_dynamic_extents;
 417   }
 418   const svalue *get_dynamic_extents (const region *reg) const;
 419   void set_dynamic_extents (const region *reg,
 420                             const svalue *size_in_bytes,
 421                             region_model_context *ctxt);
 422   void unset_dynamic_extents (const region *reg);
 423
 424   region_model_manager *get_manager () const { return m_mgr; }
 425   bounded_ranges_manager *get_range_manager () const
 426   {
 427     return m_mgr->get_range_manager ();
 428   }
 429
 430   void unbind_region_and_descendents (const region *reg,
 431                                       enum poison_kind pkind);
 432
 433   bool can_merge_with_p (const region_model &other_model,
 434                          const program_point &point,
 435                          region_model *out_model,
 436                          const extrinsic_state *ext_state = NULL,
 437                          const program_state *state_a = NULL,
 438                          const program_state *state_b = NULL) const;
 439
 440   tree get_fndecl_for_call (const gcall *call,
 441                             region_model_context *ctxt);
 442
 443   void get_regions_for_current_frame (auto_vec<const decl_region *> *out) const;
 444   static void append_regions_cb (const region *base_reg,
 445                                  struct append_regions_cb_data *data);
 446
 447   const svalue *get_store_value (const region *reg,
 448                                  region_model_context *ctxt) const;
 449
 450   bool region_exists_p (const region *reg) const;
 451
 452   void loop_replay_fixup (const region_model *dst_state);
 453
 454   const svalue *get_capacity (const region *reg) const;
 455
 456   const svalue *get_string_size (const svalue *sval) const;
 457   const svalue *get_string_size (const region *reg) const;
 458
 459   bool replay_call_summary (call_summary_replay &r,
 460                             const region_model &summary);
 461
 462   void maybe_complain_about_infoleak (const region *dst_reg,
 463                                       const svalue *copied_sval,
 464                                       const region *src_reg,
 465                                       region_model_context *ctxt);
 466
 467   void set_errno (const call_details &cd);
 468
 469   /* Implemented in sm-fd.cc  */
 470   void mark_as_valid_fd (const svalue *sval, region_model_context *ctxt);
 471
 472   /* Implemented in sm-malloc.cc  */
 473   void on_realloc_with_move (const call_details &cd,
 474                              const svalue *old_ptr_sval,
 475                              const svalue *new_ptr_sval);
 476
 477   /* Implemented in sm-taint.cc.  */
 478   void mark_as_tainted (const svalue *sval,
 479                         region_model_context *ctxt);
 480
 481   bool add_constraint (const svalue *lhs,
 482                        enum tree_code op,
 483                        const svalue *rhs,
 484                        region_model_context *ctxt);
 485
 486   const svalue *check_for_poison (const svalue *sval,
 487                                   tree expr,
 488                                   region_model_context *ctxt) const;
 489
 490   void check_region_for_write (const region *dest_reg,
 491                                region_model_context *ctxt) const;
 492
 493 private:
 494   const region *get_lvalue_1 (path_var pv, region_model_context *ctxt) const;
 495   const svalue *get_rvalue_1 (path_var pv, region_model_context *ctxt) const;
 496
 497   path_var
 498   get_representative_path_var_1 (const svalue *sval,
 499                                  svalue_set *visited) const;
 500   path_var
 501   get_representative_path_var_1 (const region *reg,
 502                                  svalue_set *visited) const;
 503
 504   const known_function *get_known_function (tree fndecl,
 505                                             const call_details &cd) const;
 506   const known_function *get_known_function (enum internal_fn) const;
 507
 508   bool add_constraints_from_binop (const svalue *outer_lhs,
 509                                    enum tree_code outer_op,
 510                                    const svalue *outer_rhs,
 511                                    bool *out,
 512                                    region_model_context *ctxt);
 513
 514   void update_for_call_superedge (const call_superedge &call_edge,
 515                                   region_model_context *ctxt);
 516   void update_for_return_superedge (const return_superedge &return_edge,
 517                                     region_model_context *ctxt);
 518   bool apply_constraints_for_gcond (const cfg_superedge &edge,
 519                                     const gcond *cond_stmt,
 520                                     region_model_context *ctxt,
 521                                     rejected_constraint **out);
 522   bool apply_constraints_for_gswitch (const switch_cfg_superedge &edge,
 523                                       const gswitch *switch_stmt,
 524                                       region_model_context *ctxt,
 525                                       rejected_constraint **out);
 526   bool apply_constraints_for_exception (const gimple *last_stmt,
 527                                         region_model_context *ctxt,
 528                                         rejected_constraint **out);
 529
 530   int poison_any_pointers_to_descendents (const region *reg,
 531                                           enum poison_kind pkind);
 532
 533   void on_top_level_param (tree param, region_model_context *ctxt);
 534
 535   bool called_from_main_p () const;
 536   const svalue *get_initial_value_for_global (const region *reg) const;
 537
 538   const region * get_region_for_poisoned_expr (tree expr) const;
 539
 540   void check_dynamic_size_for_taint (enum memory_space mem_space,
 541                                      const svalue *size_in_bytes,
 542                                      region_model_context *ctxt) const;
 543   void check_dynamic_size_for_floats (const svalue *size_in_bytes,
 544                                       region_model_context *ctxt) const;
 545
 546   void check_region_for_taint (const region *reg,
 547                                enum access_direction dir,
 548                                region_model_context *ctxt) const;
 549
 550   void check_for_writable_region (const region* dest_reg,
 551                                   region_model_context *ctxt) const;
 552   void check_region_access (const region *reg,
 553                             enum access_direction dir,
 554                             region_model_context *ctxt) const;
 555   void check_region_for_read (const region *src_reg,
 556                               region_model_context *ctxt) const;
 557   void check_region_size (const region *lhs_reg, const svalue *rhs_sval,
 558                           region_model_context *ctxt) const;
 559
 560   /* Implemented in bounds-checking.cc  */
 561   void check_symbolic_bounds (const region *base_reg,
 562                               const svalue *sym_byte_offset,
 563                               const svalue *num_bytes_sval,
 564                               const svalue *capacity,
 565                               enum access_direction dir,
 566                               region_model_context *ctxt) const;
 567   void check_region_bounds (const region *reg, enum access_direction dir,
 568                             region_model_context *ctxt) const;
 569
 570   void check_call_args (const call_details &cd) const;
 571   void check_external_function_for_access_attr (const gcall *call,
 572                                                 tree callee_fndecl,
 573                                                 region_model_context *ctxt) const;
 574
 575   /* Storing this here to avoid passing it around everywhere.  */
 576   region_model_manager *const m_mgr;
 577
 578   store m_store;
 579
 580   constraint_manager *m_constraints; // TODO: embed, rather than dynalloc?
 581
 582   const frame_region *m_current_frame;
 583
 584   /* Map from base region to size in bytes, for tracking the sizes of
 585      dynamically-allocated regions.
 586      This is part of the region_model rather than the region to allow for
 587      memory regions to be resized (e.g. by realloc).  */
 588   dynamic_extents_t m_dynamic_extents;
 589 };
 590
 591 /* Some region_model activity could lead to warnings (e.g. attempts to use an
 592    uninitialized value).  This abstract base class encapsulates an interface
 593    for the region model to use when emitting such warnings.
 594
 595    Having this as an abstract base class allows us to support the various
 596    operations needed by program_state in the analyzer within region_model,
 597    whilst keeping them somewhat modularized.  */
 598
 599 class region_model_context
 600 {
 601  public:
 602   /* Hook for clients to store pending diagnostics.
 603      Return true if the diagnostic was stored, or false if it was deleted.  */
 604   virtual bool warn (std::unique_ptr<pending_diagnostic> d) = 0;
 605
 606   /* Hook for clients to add a note to the last previously stored
 607      pending diagnostic.  */
 608   virtual void add_note (std::unique_ptr<pending_note> pn) = 0;
 609
 610   /* Hook for clients to be notified when an SVAL that was reachable
 611      in a previous state is no longer live, so that clients can emit warnings
 612      about leaks.  */
 613   virtual void on_svalue_leak (const svalue *sval) = 0;
 614
 615   /* Hook for clients to be notified when the set of explicitly live
 616      svalues changes, so that they can purge state relating to dead
 617      svalues.  */
 618   virtual void on_liveness_change (const svalue_set &live_svalues,
 619                                    const region_model *model) = 0;
 620
 621   virtual logger *get_logger () = 0;
 622
 623   /* Hook for clients to be notified when the condition
 624      "LHS OP RHS" is added to the region model.
 625      This exists so that state machines can detect tests on edges,
 626      and use them to trigger sm-state transitions (e.g. transitions due
 627      to ptrs becoming known to be NULL or non-NULL, rather than just
 628      "unchecked") */
 629   virtual void on_condition (const svalue *lhs,
 630                              enum tree_code op,
 631                              const svalue *rhs) = 0;
 632
 633   /* Hook for clients to be notified when the condition that
 634      SVAL is within RANGES is added to the region model.
 635      Similar to on_condition, but for use when handling switch statements.
 636      RANGES is non-empty.  */
 637   virtual void on_bounded_ranges (const svalue &sval,
 638                                   const bounded_ranges &ranges) = 0;
 639
 640   /* Hook for clients to be notified when a frame is popped from the stack.  */
 641   virtual void on_pop_frame (const frame_region *) = 0;
 642
 643   /* Hooks for clients to be notified when an unknown change happens
 644      to SVAL (in response to a call to an unknown function).  */
 645   virtual void on_unknown_change (const svalue *sval, bool is_mutable) = 0;
 646
 647   /* Hooks for clients to be notified when a phi node is handled,
 648      where RHS is the pertinent argument.  */
 649   virtual void on_phi (const gphi *phi, tree rhs) = 0;
 650
 651   /* Hooks for clients to be notified when the region model doesn't
 652      know how to handle the tree code of T at LOC.  */
 653   virtual void on_unexpected_tree_code (tree t,
 654                                         const dump_location_t &loc) = 0;
 655
 656   /* Hook for clients to be notified when a function_decl escapes.  */
 657   virtual void on_escaped_function (tree fndecl) = 0;
 658
 659   virtual uncertainty_t *get_uncertainty () = 0;
 660
 661   /* Hook for clients to purge state involving SVAL.  */
 662   virtual void purge_state_involving (const svalue *sval) = 0;
 663
 664   /* Hook for clients to split state with a non-standard path.  */
 665   virtual void bifurcate (std::unique_ptr<custom_edge_info> info) = 0;
 666
 667   /* Hook for clients to terminate the standard path.  */
 668   virtual void terminate_path () = 0;
 669
 670   virtual const extrinsic_state *get_ext_state () const = 0;
 671
 672   /* Hook for clients to access the a specific state machine in
 673      any underlying program_state.  */
 674   virtual bool
 675   get_state_map_by_name (const char *name,
 676                          sm_state_map **out_smap,
 677                          const state_machine **out_sm,
 678                          unsigned *out_sm_idx,
 679                          std::unique_ptr<sm_context> *out_sm_context) = 0;
 680
 681   /* Precanned ways for clients to access specific state machines.  */
 682   bool get_fd_map (sm_state_map **out_smap,
 683                    const state_machine **out_sm,
 684                    unsigned *out_sm_idx,
 685                    std::unique_ptr<sm_context> *out_sm_context)
 686   {
 687     return get_state_map_by_name ("file-descriptor", out_smap, out_sm,
 688                                   out_sm_idx, out_sm_context);
 689   }
 690   bool get_malloc_map (sm_state_map **out_smap,
 691                        const state_machine **out_sm,
 692                        unsigned *out_sm_idx)
 693   {
 694     return get_state_map_by_name ("malloc", out_smap, out_sm, out_sm_idx, NULL);
 695   }
 696   bool get_taint_map (sm_state_map **out_smap,
 697                       const state_machine **out_sm,
 698                       unsigned *out_sm_idx)
 699   {
 700     return get_state_map_by_name ("taint", out_smap, out_sm, out_sm_idx, NULL);
 701   }
 702
 703   /* Get the current statement, if any.  */
 704   virtual const gimple *get_stmt () const = 0;
 705 };
 706
 707 /* A "do nothing" subclass of region_model_context.  */
 708
 709 class noop_region_model_context : public region_model_context
 710 {
 711 public:
 712   bool warn (std::unique_ptr<pending_diagnostic>) override { return false; }
 713   void add_note (std::unique_ptr<pending_note>) override;
 714   void on_svalue_leak (const svalue *) override {}
 715   void on_liveness_change (const svalue_set &,
 716                            const region_model *) override {}
 717   logger *get_logger () override { return NULL; }
 718   void on_condition (const svalue *lhs ATTRIBUTE_UNUSED,
 719                      enum tree_code op ATTRIBUTE_UNUSED,
 720                      const svalue *rhs ATTRIBUTE_UNUSED) override
 721   {
 722   }
 723   void on_bounded_ranges (const svalue &,
 724                           const bounded_ranges &) override
 725   {
 726   }
 727   void on_pop_frame (const frame_region *) override {}
 728   void on_unknown_change (const svalue *sval ATTRIBUTE_UNUSED,
 729                           bool is_mutable ATTRIBUTE_UNUSED) override
 730   {
 731   }
 732   void on_phi (const gphi *phi ATTRIBUTE_UNUSED,
 733                tree rhs ATTRIBUTE_UNUSED) override
 734   {
 735   }
 736   void on_unexpected_tree_code (tree, const dump_location_t &) override {}
 737
 738   void on_escaped_function (tree) override {}
 739
 740   uncertainty_t *get_uncertainty () override { return NULL; }
 741
 742   void purge_state_involving (const svalue *sval ATTRIBUTE_UNUSED) override {}
 743
 744   void bifurcate (std::unique_ptr<custom_edge_info> info) override;
 745   void terminate_path () override;
 746
 747   const extrinsic_state *get_ext_state () const override { return NULL; }
 748
 749   bool get_state_map_by_name (const char *,
 750                               sm_state_map **,
 751                               const state_machine **,
 752                               unsigned *,
 753                               std::unique_ptr<sm_context> *) override
 754   {
 755     return false;
 756   }
 757
 758   const gimple *get_stmt () const override { return NULL; }
 759 };
 760
 761 /* A subclass of region_model_context for determining if operations fail
 762    e.g. "can we generate a region for the lvalue of EXPR?".  */
 763
 764 class tentative_region_model_context : public noop_region_model_context
 765 {
 766 public:
 767   tentative_region_model_context () : m_num_unexpected_codes (0) {}
 768
 769   void on_unexpected_tree_code (tree, const dump_location_t &)
 770     final override
 771   {
 772     m_num_unexpected_codes++;
 773   }
 774
 775   bool had_errors_p () const { return m_num_unexpected_codes > 0; }
 776
 777 private:
 778   int m_num_unexpected_codes;
 779 };
 780
 781 /* Subclass of region_model_context that wraps another context, allowing
 782    for extra code to be added to the various hooks.  */
 783
 784 class region_model_context_decorator : public region_model_context
 785 {
 786  public:
 787   bool warn (std::unique_ptr<pending_diagnostic> d) override
 788   {
 789     return m_inner->warn (std::move (d));
 790   }
 791
 792   void add_note (std::unique_ptr<pending_note> pn) override
 793   {
 794     m_inner->add_note (std::move (pn));
 795   }
 796
 797   void on_svalue_leak (const svalue *sval) override
 798   {
 799     m_inner->on_svalue_leak (sval);
 800   }
 801
 802   void on_liveness_change (const svalue_set &live_svalues,
 803                            const region_model *model) override
 804   {
 805     m_inner->on_liveness_change (live_svalues, model);
 806   }
 807
 808   logger *get_logger () override
 809   {
 810     return m_inner->get_logger ();
 811   }
 812
 813   void on_condition (const svalue *lhs,
 814                      enum tree_code op,
 815                      const svalue *rhs) override
 816   {
 817     m_inner->on_condition (lhs, op, rhs);
 818   }
 819
 820   void on_bounded_ranges (const svalue &sval,
 821                           const bounded_ranges &ranges) override
 822   {
 823     m_inner->on_bounded_ranges (sval, ranges);
 824   }
 825
 826   void on_pop_frame (const frame_region *frame_reg) override
 827   {
 828     m_inner->on_pop_frame (frame_reg);
 829   }
 830
 831   void on_unknown_change (const svalue *sval, bool is_mutable) override
 832   {
 833     m_inner->on_unknown_change (sval, is_mutable);
 834   }
 835
 836   void on_phi (const gphi *phi, tree rhs) override
 837   {
 838     m_inner->on_phi (phi, rhs);
 839   }
 840
 841   void on_unexpected_tree_code (tree t,
 842                                 const dump_location_t &loc) override
 843   {
 844     m_inner->on_unexpected_tree_code (t, loc);
 845   }
 846
 847   void on_escaped_function (tree fndecl) override
 848   {
 849     m_inner->on_escaped_function (fndecl);
 850   }
 851
 852   uncertainty_t *get_uncertainty () override
 853   {
 854     return m_inner->get_uncertainty ();
 855   }
 856
 857   void purge_state_involving (const svalue *sval) override
 858   {
 859     m_inner->purge_state_involving (sval);
 860   }
 861
 862   void bifurcate (std::unique_ptr<custom_edge_info> info) override
 863   {
 864     m_inner->bifurcate (std::move (info));
 865   }
 866
 867   void terminate_path () override
 868   {
 869     m_inner->terminate_path ();
 870   }
 871
 872   const extrinsic_state *get_ext_state () const override
 873   {
 874     return m_inner->get_ext_state ();
 875   }
 876
 877   bool get_state_map_by_name (const char *name,
 878                               sm_state_map **out_smap,
 879                               const state_machine **out_sm,
 880                               unsigned *out_sm_idx,
 881                               std::unique_ptr<sm_context> *out_sm_context)
 882     override
 883   {
 884     return m_inner->get_state_map_by_name (name, out_smap, out_sm, out_sm_idx,
 885                                            out_sm_context);
 886   }
 887
 888   const gimple *get_stmt () const override
 889   {
 890     return m_inner->get_stmt ();
 891   }
 892
 893 protected:
 894   region_model_context_decorator (region_model_context *inner)
 895   : m_inner (inner)
 896   {
 897     gcc_assert (m_inner);
 898   }
 899
 900   region_model_context *m_inner;
 901 };
 902
 903 /* Subclass of region_model_context_decorator that adds a note
 904    when saving diagnostics.  */
 905
 906 class note_adding_context : public region_model_context_decorator
 907 {
 908 public:
 909   bool warn (std::unique_ptr<pending_diagnostic> d) override
 910   {
 911     if (m_inner->warn (std::move (d)))
 912       {
 913         add_note (make_note ());
 914         return true;
 915       }
 916     else
 917       return false;
 918   }
 919
 920   /* Hook to make the new note.  */
 921   virtual std::unique_ptr<pending_note> make_note () = 0;
 922
 923 protected:
 924   note_adding_context (region_model_context *inner)
 925   : region_model_context_decorator (inner)
 926   {
 927   }
 928 };
 929
 930 /* A bundle of data for use when attempting to merge two region_model
 931    instances to make a third.  */
 932
 933 struct model_merger
 934 {
 935   model_merger (const region_model *model_a,
 936                 const region_model *model_b,
 937                 const program_point &point,
 938                 region_model *merged_model,
 939                 const extrinsic_state *ext_state,
 940                 const program_state *state_a,
 941                 const program_state *state_b)
 942   : m_model_a (model_a), m_model_b (model_b),
 943     m_point (point),
 944     m_merged_model (merged_model),
 945     m_ext_state (ext_state),
 946     m_state_a (state_a), m_state_b (state_b)
 947   {
 948   }
 949
 950   void dump_to_pp (pretty_printer *pp, bool simple) const;
 951   void dump (FILE *fp, bool simple) const;
 952   void dump (bool simple) const;
 953
 954   region_model_manager *get_manager () const
 955   {
 956     return m_model_a->get_manager ();
 957   }
 958
 959   bool mergeable_svalue_p (const svalue *) const;
 960   const function_point &get_function_point () const
 961   {
 962     return m_point.get_function_point ();
 963   }
 964
 965   const region_model *m_model_a;
 966   const region_model *m_model_b;
 967   const program_point &m_point;
 968   region_model *m_merged_model;
 969
 970   const extrinsic_state *m_ext_state;
 971   const program_state *m_state_a;
 972   const program_state *m_state_b;
 973 };
 974
 975 /* A record that can (optionally) be written out when
 976    region_model::add_constraint fails.  */
 977
 978 class rejected_constraint
 979 {
 980 public:
 981   virtual ~rejected_constraint () {}
 982   virtual void dump_to_pp (pretty_printer *pp) const = 0;
 983
 984   const region_model &get_model () const { return m_model; }
 985
 986 protected:
 987   rejected_constraint (const region_model &model)
 988   : m_model (model)
 989   {}
 990
 991   region_model m_model;
 992 };
 993
 994 class rejected_op_constraint : public rejected_constraint
 995 {
 996 public:
 997   rejected_op_constraint (const region_model &model,
 998                           tree lhs, enum tree_code op, tree rhs)
 999   : rejected_constraint (model),
1000     m_lhs (lhs), m_op (op), m_rhs (rhs)
1001   {}
1002
1003   void dump_to_pp (pretty_printer *pp) const final override;
1004
1005   tree m_lhs;
1006   enum tree_code m_op;
1007   tree m_rhs;
1008 };
1009
1010 class rejected_ranges_constraint : public rejected_constraint
1011 {
1012 public:
1013   rejected_ranges_constraint (const region_model &model,
1014                               tree expr, const bounded_ranges *ranges)
1015   : rejected_constraint (model),
1016     m_expr (expr), m_ranges (ranges)
1017   {}
1018
1019   void dump_to_pp (pretty_printer *pp) const final override;
1020
1021 private:
1022   tree m_expr;
1023   const bounded_ranges *m_ranges;
1024 };
1025
1026 /* A bundle of state.  */
1027
1028 class engine
1029 {
1030 public:
1031   engine (const supergraph *sg = NULL, logger *logger = NULL);
1032   const supergraph *get_supergraph () { return m_sg; }
1033   region_model_manager *get_model_manager () { return &m_mgr; }
1034   known_function_manager *get_known_function_manager ()
1035   {
1036     return m_mgr.get_known_function_manager ();
1037   }
1038
1039   void log_stats (logger *logger) const;
1040
1041 private:
1042   const supergraph *m_sg;
1043   region_model_manager m_mgr;
1044 };
1045
1046 } // namespace ana
1047
1048 extern void debug (const region_model &rmodel);
1049
1050 namespace ana {
1051
1052 #if CHECKING_P
1053
1054 namespace selftest {
1055
1056 using namespace ::selftest;
1057
1058 /* An implementation of region_model_context for use in selftests, which
1059    stores any pending_diagnostic instances passed to it.  */
1060
1061 class test_region_model_context : public noop_region_model_context
1062 {
1063 public:
1064   bool warn (std::unique_ptr<pending_diagnostic> d) final override
1065   {
1066     m_diagnostics.safe_push (d.release ());
1067     return true;
1068   }
1069
1070   unsigned get_num_diagnostics () const { return m_diagnostics.length (); }
1071
1072   void on_unexpected_tree_code (tree t, const dump_location_t &)
1073     final override
1074   {
1075     internal_error ("unhandled tree code: %qs",
1076                     get_tree_code_name (TREE_CODE (t)));
1077   }
1078
1079 private:
1080   /* Implicitly delete any diagnostics in the dtor.  */
1081   auto_delete_vec<pending_diagnostic> m_diagnostics;
1082 };
1083
1084 /* Attempt to add the constraint (LHS OP RHS) to MODEL.
1085    Verify that MODEL remains satisfiable.  */
1086
1087 #define ADD_SAT_CONSTRAINT(MODEL, LHS, OP, RHS) \
1088   SELFTEST_BEGIN_STMT                                   \
1089     bool sat = (MODEL).add_constraint (LHS, OP, RHS, NULL);     \
1090     ASSERT_TRUE (sat);                                  \
1091   SELFTEST_END_STMT
1092
1093 /* Attempt to add the constraint (LHS OP RHS) to MODEL.
1094    Verify that the result is not satisfiable.  */
1095
1096 #define ADD_UNSAT_CONSTRAINT(MODEL, LHS, OP, RHS)       \
1097   SELFTEST_BEGIN_STMT                                   \
1098     bool sat = (MODEL).add_constraint (LHS, OP, RHS, NULL);     \
1099     ASSERT_FALSE (sat);                         \
1100   SELFTEST_END_STMT
1101
1102 /* Implementation detail of the ASSERT_CONDITION_* macros.  */
1103
1104 void assert_condition (const location &loc,
1105                        region_model &model,
1106                        const svalue *lhs, tree_code op, const svalue *rhs,
1107                        tristate expected);
1108
1109 void assert_condition (const location &loc,
1110                        region_model &model,
1111                        tree lhs, tree_code op, tree rhs,
1112                        tristate expected);
1113
1114 /* Assert that REGION_MODEL evaluates the condition "LHS OP RHS"
1115    as "true".  */
1116
1117 #define ASSERT_CONDITION_TRUE(REGION_MODEL, LHS, OP, RHS) \
1118   SELFTEST_BEGIN_STMT                                                   \
1119   assert_condition (SELFTEST_LOCATION, REGION_MODEL, LHS, OP, RHS,      \
1120                     tristate (tristate::TS_TRUE));              \
1121   SELFTEST_END_STMT
1122
1123 /* Assert that REGION_MODEL evaluates the condition "LHS OP RHS"
1124    as "false".  */
1125
1126 #define ASSERT_CONDITION_FALSE(REGION_MODEL, LHS, OP, RHS) \
1127   SELFTEST_BEGIN_STMT                                                   \
1128   assert_condition (SELFTEST_LOCATION, REGION_MODEL, LHS, OP, RHS,      \
1129                     tristate (tristate::TS_FALSE));             \
1130   SELFTEST_END_STMT
1131
1132 /* Assert that REGION_MODEL evaluates the condition "LHS OP RHS"
1133    as "unknown".  */
1134
1135 #define ASSERT_CONDITION_UNKNOWN(REGION_MODEL, LHS, OP, RHS) \
1136   SELFTEST_BEGIN_STMT                                                   \
1137   assert_condition (SELFTEST_LOCATION, REGION_MODEL, LHS, OP, RHS,      \
1138                     tristate (tristate::TS_UNKNOWN));           \
1139   SELFTEST_END_STMT
1140
1141 } /* end of namespace selftest.  */
1142
1143 #endif /* #if CHECKING_P */
1144
1145 } // namespace ana
1146
1147 #endif /* GCC_ANALYZER_REGION_MODEL_H */