smatch_slist.c

   1 /*
   2  * sparse/smatch_slist.c
   3  *
   4  * Copyright (C) 2008,2009 Dan Carpenter.
   5  *
   6  *  Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include "smatch.h"
  13 #include "smatch.h"
  14 #include "smatch_slist.h"
  15
  16 #undef CHECKORDER
  17
  18 ALLOCATOR(sm_state, "smatch state");
  19 ALLOCATOR(named_slist, "named slist");
  20
  21 void __print_slist(struct state_list *slist)
  22 {
  23         struct sm_state *state;
  24
  25         printf("dumping slist at %d\n", get_lineno());
  26         FOR_EACH_PTR(slist, state) {
  27                 printf("%d '%s'=%s\n", state->owner, state->name,
  28                         show_state(state->state));
  29         } END_FOR_EACH_PTR(state);
  30         printf("---\n");
  31 }
  32
  33 void add_history(struct sm_state *state)
  34 {
  35         struct state_history *tmp;
  36
  37         if (!state)
  38                 return;
  39         tmp = malloc(sizeof(*tmp));
  40         tmp->loc = get_lineno();
  41         add_ptr_list(&state->line_history, tmp);
  42 }
  43
  44
  45 /* NULL states go at the end to simplify merge_slist */
  46 static int cmp_tracker(const struct sm_state *a, const struct sm_state *b)
  47 {
  48         int ret;
  49
  50         if (!a && !b)
  51                 return 0;
  52         if (!b)
  53                 return -1;
  54         if (!a)
  55                 return 1;
  56
  57         if (a->owner > b->owner)
  58                 return -1;
  59         if (a->owner < b->owner)
  60                 return 1;
  61
  62         ret = strcmp(a->name, b->name);
  63         if (ret)
  64                 return ret;
  65
  66         if (!b->sym && a->sym)
  67                 return -1;
  68         if (!a->sym && b->sym)
  69                 return 1;
  70         if (a->sym > b->sym)
  71                 return -1;
  72         if (a->sym < b->sym)
  73                 return 1;
  74
  75         return 0;
  76 }
  77
  78 static int cmp_sm_states(const struct sm_state *a, const struct sm_state *b)
  79 {
  80         int ret;
  81
  82         ret = cmp_tracker(a, b);
  83         if (ret)
  84                 return ret;
  85
  86         /* todo:  add hook for smatch_extra.c */
  87         if (a->state > b->state)
  88                 return -1;
  89         if (a->state < b->state)
  90                 return 1;
  91         return 0;
  92 }
  93
  94 void add_sm_state_slist(struct state_list **slist, struct sm_state *new)
  95 {
  96         struct sm_state *tmp;
  97
  98         FOR_EACH_PTR(*slist, tmp) {
  99                 if (cmp_sm_states(tmp, new) < 0)
 100                         continue;
 101                 else if (cmp_sm_states(tmp, new) == 0) {
 102                         return;
 103                 } else {
 104                         INSERT_CURRENT(new, tmp);
 105                         return;
 106                 }
 107         } END_FOR_EACH_PTR(tmp);
 108         add_ptr_list(slist, new);
 109 }
 110
 111 static void add_possible(struct sm_state *sm, struct sm_state *new)
 112 {
 113         struct sm_state *tmp;
 114
 115
 116         if (!new) {
 117                 struct smatch_state *s;
 118
 119                 s = merge_states(sm->name, sm->owner, sm->sym, sm->state, NULL);
 120                 tmp = alloc_state(sm->name, sm->owner, sm->sym, s);
 121                 add_sm_state_slist(&sm->possible, tmp);
 122                 return;
 123         }
 124         FOR_EACH_PTR(new->possible, tmp) {
 125                 add_sm_state_slist(&sm->possible, tmp);
 126         } END_FOR_EACH_PTR(tmp);
 127 }
 128
 129 struct sm_state *alloc_state(const char *name, int owner,
 130                              struct symbol *sym, struct smatch_state *state)
 131 {
 132         struct sm_state *sm_state = __alloc_sm_state(0);
 133
 134         sm_state->name = (char *)name;
 135         sm_state->owner = owner;
 136         sm_state->sym = sym;
 137         sm_state->state = state;
 138         sm_state->line_history = NULL;
 139         add_history(sm_state);
 140         sm_state->pools = NULL;
 141         sm_state->possible = NULL;
 142         add_ptr_list(&sm_state->possible, sm_state);
 143         return sm_state;
 144 }
 145
 146 struct sm_state *clone_state(struct sm_state *s)
 147 {
 148         struct sm_state *tmp;
 149
 150         tmp = alloc_state(s->name, s->owner, s->sym, s->state);
 151         tmp->pools = clone_stack(s->pools);
 152         tmp->possible = s->possible;
 153         return tmp;
 154 }
 155
 156 int slist_has_state(struct state_list *slist, struct smatch_state *state)
 157 {
 158         struct sm_state *tmp;
 159
 160         FOR_EACH_PTR(slist, tmp) {
 161                 if (tmp->state == state)
 162                         return 1;
 163         } END_FOR_EACH_PTR(tmp);
 164         return 0;
 165 }
 166
 167 #ifdef CHECKORDER
 168 static void check_order(struct state_list *slist)
 169 {
 170         struct sm_state *state;
 171         struct sm_state *last = NULL;
 172         int printed = 0;
 173
 174         FOR_EACH_PTR(slist, state) {
 175                 if (last && cmp_tracker(state, last) <= 0) {
 176                         printf("Error.  Unsorted slist %d vs %d, %p vs %p, "
 177                                "%s vs %s\n", last->owner, state->owner,
 178                                last->sym, state->sym, last->name, state->name);
 179                         printed = 1;
 180                 }
 181                 last = state;
 182         } END_FOR_EACH_PTR(state);
 183
 184         if (printed)
 185                 printf("======\n");
 186 }
 187 #endif
 188
 189 struct state_list *clone_slist(struct state_list *from_slist)
 190 {
 191         struct sm_state *state;
 192         struct sm_state *tmp;
 193         struct state_list *to_slist = NULL;
 194
 195         FOR_EACH_PTR(from_slist, state) {
 196                 tmp = clone_state(state);
 197                 add_ptr_list(&to_slist, tmp);
 198         } END_FOR_EACH_PTR(state);
 199 #ifdef CHECKORDER
 200         check_order(to_slist);
 201 #endif
 202         return to_slist;
 203 }
 204
 205 struct state_list_stack *clone_stack(struct state_list_stack *from_stack)
 206 {
 207         struct state_list *slist;
 208         struct state_list_stack *to_stack = NULL;
 209
 210         FOR_EACH_PTR(from_stack, slist) {
 211                 push_slist(&to_stack, slist);
 212         } END_FOR_EACH_PTR(slist);
 213         return to_stack;
 214 }
 215
 216 // FIXME...  shouldn't we free some of these state pointers?
 217 struct smatch_state *merge_states(const char *name, int owner,
 218                                   struct symbol *sym,
 219                                   struct smatch_state *state1,
 220                                   struct smatch_state *state2)
 221 {
 222         struct smatch_state *ret;
 223
 224         if (state1 == state2)
 225                 ret = state1;
 226         else if (__has_merge_function(owner))
 227                 ret = __client_merge_function(owner, name, sym, state1, state2);
 228         else
 229                 ret = &merged;
 230
 231         SM_DEBUG("%d merge name='%s' owner=%d: %s + %s => %s\n",
 232                  get_lineno(), name, owner, show_state(state1),
 233                  show_state(state2), show_state(ret));
 234
 235         return ret;
 236 }
 237
 238 struct sm_state *merge_sm_states(struct sm_state *one, struct sm_state *two)
 239 {
 240         struct smatch_state *s;
 241         struct sm_state *result;
 242
 243         s = merge_states(one->name, one->owner, one->sym, one->state,
 244                         (two?two->state:NULL));
 245         result = alloc_state(one->name, one->owner, one->sym, s);
 246         add_possible(result, one);
 247         add_possible(result, two);
 248         return result;
 249 }
 250
 251 struct sm_state *get_sm_state_slist(struct state_list *slist, const char *name,
 252                                 int owner, struct symbol *sym)
 253 {
 254         struct sm_state *state;
 255
 256         if (!name)
 257                 return NULL;
 258
 259         FOR_EACH_PTR(slist, state) {
 260                 if (state->owner == owner && state->sym == sym
 261                     && !strcmp(state->name, name))
 262                         return state;
 263         } END_FOR_EACH_PTR(state);
 264         return NULL;
 265 }
 266
 267 struct smatch_state *get_state_slist(struct state_list *slist,
 268                                 const char *name, int owner,
 269                                 struct symbol *sym)
 270 {
 271         struct sm_state *state;
 272
 273         state = get_sm_state_slist(slist, name, owner, sym);
 274         if (state)
 275                 return state->state;
 276         return NULL;
 277 }
 278
 279 static void overwrite_sm_state(struct state_list **slist,
 280                                struct sm_state *state)
 281 {
 282         struct sm_state *tmp;
 283         struct sm_state *new = clone_state(state); //fixme. why?
 284
 285         FOR_EACH_PTR(*slist, tmp) {
 286                 if (cmp_tracker(tmp, new) < 0)
 287                         continue;
 288                 else if (cmp_tracker(tmp, new) == 0) {
 289                         tmp->state = new->state;
 290                         tmp->pools = new->pools;
 291                         tmp->possible = new->possible;
 292                         __free_sm_state(new);
 293                         return;
 294                 } else {
 295                         INSERT_CURRENT(new, tmp);
 296                         return;
 297                 }
 298         } END_FOR_EACH_PTR(tmp);
 299         add_ptr_list(slist, new);
 300 }
 301
 302 void set_state_slist(struct state_list **slist, const char *name, int owner,
 303                      struct symbol *sym, struct smatch_state *state)
 304 {
 305         struct sm_state *tmp;
 306         struct sm_state *new = alloc_state(name, owner, sym, state);
 307
 308         FOR_EACH_PTR(*slist, tmp) {
 309                 if (cmp_tracker(tmp, new) < 0)
 310                         continue;
 311                 else if (cmp_tracker(tmp, new) == 0) {
 312                         tmp->state = state;
 313                         tmp->pools = NULL;
 314                         tmp->possible = NULL;
 315                         add_ptr_list(&tmp->possible, tmp);
 316                         __free_sm_state(new);
 317                         return;
 318                 } else {
 319                         INSERT_CURRENT(new, tmp);
 320                         return;
 321                 }
 322         } END_FOR_EACH_PTR(tmp);
 323         add_ptr_list(slist, new);
 324 }
 325
 326 void delete_state_slist(struct state_list **slist, const char *name, int owner,
 327                         struct symbol *sym)
 328 {
 329         struct sm_state *state;
 330
 331         FOR_EACH_PTR(*slist, state) {
 332                 if (state->owner == owner && state->sym == sym
 333                     && !strcmp(state->name, name)){
 334                         delete_ptr_list_entry((struct ptr_list **)slist,
 335                                               state, 1);
 336                         __free_sm_state(state);
 337                         return;
 338                 }
 339         } END_FOR_EACH_PTR(state);
 340 }
 341
 342
 343 void push_slist(struct state_list_stack **list_stack, struct state_list *slist)
 344 {
 345         add_ptr_list(list_stack, slist);
 346 }
 347
 348 struct state_list *pop_slist(struct state_list_stack **list_stack)
 349 {
 350         struct state_list *slist;
 351
 352         slist = last_ptr_list((struct ptr_list *)*list_stack);
 353         delete_ptr_list_last((struct ptr_list **)list_stack);
 354         return slist;
 355 }
 356
 357 void del_slist(struct state_list **slist)
 358 {
 359         __free_ptr_list((struct ptr_list **)slist);
 360 }
 361
 362 void del_slist_stack(struct state_list_stack **slist_stack)
 363 {
 364         struct state_list *slist;
 365
 366         FOR_EACH_PTR(*slist_stack, slist) {
 367                 __free_ptr_list((struct ptr_list **)&slist);
 368         } END_FOR_EACH_PTR(slist);
 369         __free_ptr_list((struct ptr_list **)slist_stack);
 370 }
 371
 372 /*
 373  * set_state_stack() sets the state for the top slist on the stack.
 374  */
 375 void set_state_stack(struct state_list_stack **stack, const char *name,
 376                      int owner, struct symbol *sym, struct smatch_state *state)
 377 {
 378         struct state_list *slist;
 379
 380         slist = pop_slist(stack);
 381         set_state_slist(&slist, name, owner, sym, state);
 382         push_slist(stack, slist);
 383 }
 384
 385 /*
 386  * get_state_stack() gets the state for the top slist on the stack.
 387  */
 388 struct smatch_state *get_state_stack(struct state_list_stack *stack,
 389                                      const char *name, int owner,
 390                                      struct symbol *sym)
 391 {
 392         struct state_list *slist;
 393         struct smatch_state *ret;
 394
 395         slist = pop_slist(&stack);
 396         ret = get_state_slist(slist, name, owner, sym);
 397         push_slist(&stack, slist);
 398         return ret;
 399 }
 400
 401 /*
 402  * add_pool() adds a slist to ->pools. If the slist has already been
 403  * added earlier then it doesn't get added a second time.
 404  */
 405 static void add_pool(struct sm_state *to, struct state_list *new)
 406 {
 407         struct state_list *tmp;
 408
 409         FOR_EACH_PTR(to->pools, tmp) {
 410                 if (tmp < new)
 411                         continue;
 412                 else if (tmp == new) {
 413                         return;
 414                 } else {
 415                         INSERT_CURRENT(new, tmp);
 416                         return;
 417                 }
 418         } END_FOR_EACH_PTR(tmp);
 419         add_ptr_list(&to->pools, new);
 420 }
 421
 422 static void copy_pools(struct sm_state *to, struct sm_state *sm)
 423 {
 424         struct state_list *tmp;
 425
 426         FOR_EACH_PTR(sm->pools, tmp) {
 427                 add_pool(to, tmp);
 428         } END_FOR_EACH_PTR(tmp);
 429 }
 430
 431 /*
 432  * merge_slist() is called whenever paths merge, such as after
 433  * an if statement.  It takes the two slists and creates one.
 434  */
 435 void merge_slist(struct state_list **to, struct state_list *slist)
 436 {
 437         struct sm_state *to_state, *state, *tmp;
 438         struct state_list *results = NULL;
 439         struct state_list *implied_to = NULL;
 440         struct state_list *implied_from = NULL;
 441
 442 #ifdef CHECKORDER
 443         check_order(*to);
 444         check_order(slist);
 445 #endif
 446
 447         /* merging a null and nonnull path gives you only the nonnull path */
 448         if (!slist) {
 449                 return;
 450         }
 451         if (!*to) {
 452                 *to = clone_slist(slist);
 453                 return;
 454         }
 455
 456         PREPARE_PTR_LIST(*to, to_state);
 457         PREPARE_PTR_LIST(slist, state);
 458         for (;;) {
 459                 if (!to_state && !state)
 460                         break;
 461                 if (cmp_tracker(to_state, state) < 0) {
 462                         tmp = merge_sm_states(to_state, NULL);
 463
 464                         copy_pools(tmp, to_state);
 465
 466                         add_ptr_list(&implied_to, to_state);
 467                         add_pool(tmp, implied_to);
 468
 469                         add_ptr_list(&results, tmp);
 470                         NEXT_PTR_LIST(to_state);
 471                 } else if (cmp_tracker(to_state, state) == 0) {
 472                         if (to_state->state == state->state) {
 473                                 tmp = to_state;
 474                         } else {
 475                                 tmp = merge_sm_states(to_state, state);
 476
 477                                 copy_pools(tmp, to_state);
 478                                 copy_pools(tmp, state);
 479
 480                                 add_ptr_list(&implied_to, to_state);
 481                                 add_pool(tmp, implied_to);
 482                                 add_ptr_list(&implied_from, state);
 483                                 add_pool(tmp, implied_from);
 484                         }
 485                         add_ptr_list(&results, tmp);
 486                         NEXT_PTR_LIST(to_state);
 487                         NEXT_PTR_LIST(state);
 488                 } else {
 489                         tmp = merge_sm_states(state, NULL);
 490
 491                         copy_pools(tmp, state);
 492
 493                         add_ptr_list(&implied_from, state);
 494                         add_pool(tmp, implied_from);
 495
 496                         add_ptr_list(&results, tmp);
 497                         NEXT_PTR_LIST(state);
 498                 }
 499         }
 500         FINISH_PTR_LIST(state);
 501         FINISH_PTR_LIST(to_state);
 502
 503         del_slist(to);
 504         *to = results;
 505
 506         if (implied_from)
 507                 push_slist(&implied_pools, implied_from);
 508         if (implied_to)
 509                 push_slist(&implied_pools, implied_to);
 510 }
 511
 512 /*
 513  * is_currently_in_pool() is used because we remove states from pools.
 514  * When set_state() is called then we set ->pools to NULL, but on
 515  * other paths the state is still a member of those pools.
 516  * Confusing huh?
 517  * if (foo) {
 518  *        bar = 1;
 519  *        a = malloc();
 520  * }
 521  * if (!a)
 522  *        return;
 523  * if (bar)
 524  *        a->b = x;
 525  */
 526 static int is_currently_in_pool(struct sm_state *sm, struct state_list *pool,
 527                         struct state_list *cur_slist)
 528 {
 529         struct sm_state *cur_state;
 530         struct state_list *tmp;
 531
 532         cur_state = get_sm_state_slist(cur_slist, sm->name, sm->owner, sm->sym);
 533         if (!cur_state)
 534                 return 0;
 535
 536         FOR_EACH_PTR(cur_state->pools, tmp) {
 537                 if (tmp == pool)
 538                         return 1;
 539         } END_FOR_EACH_PTR(tmp);
 540         return 0;
 541 }
 542
 543 struct state_list *clone_states_in_pool(struct state_list *pool,
 544                                 struct state_list *cur_slist)
 545 {
 546         struct sm_state *state;
 547         struct sm_state *tmp;
 548         struct state_list *to_slist = NULL;
 549
 550         FOR_EACH_PTR(pool, state) {
 551                 if (is_currently_in_pool(state, pool, cur_slist)) {
 552                         tmp = clone_state(state);
 553                         add_ptr_list(&to_slist, tmp);
 554                 }
 555         } END_FOR_EACH_PTR(state);
 556 #ifdef CHECKORDER
 557         check_order(to_slist);
 558 #endif
 559         return to_slist;
 560 }
 561
 562 /*
 563  * filter() is used to find what states are the same across
 564  * a series of slists.
 565  * It takes a **slist and a *filter.
 566  * It removes everything from **slist that isn't in *filter.
 567  * The reason you would want to do this is if you want to
 568  * know what other states are true if one state is true.  (smatch_implied).
 569  */
 570 void filter(struct state_list **slist, struct state_list *filter,
 571         struct state_list *cur_slist)
 572 {
 573         struct sm_state *s_one, *s_two;
 574         struct state_list *results = NULL;
 575
 576 #ifdef CHECKORDER
 577         check_order(*slist);
 578         check_order(filter);
 579 #endif
 580
 581         PREPARE_PTR_LIST(*slist, s_one);
 582         PREPARE_PTR_LIST(filter, s_two);
 583         for (;;) {
 584                 if (!s_one || !s_two)
 585                         break;
 586                 if (cmp_tracker(s_one, s_two) < 0) {
 587                         NEXT_PTR_LIST(s_one);
 588                 } else if (cmp_tracker(s_one, s_two) == 0) {
 589                         /* todo.  pointer comparison works fine for most things
 590                            except smatch_extra.  we may need a hook here. */
 591                         if (s_one->state == s_two->state &&
 592                                 is_currently_in_pool(s_two, filter, cur_slist)) {
 593                                 add_ptr_list(&results, s_one);
 594                         }
 595                         NEXT_PTR_LIST(s_one);
 596                         NEXT_PTR_LIST(s_two);
 597                 } else {
 598                         NEXT_PTR_LIST(s_two);
 599                 }
 600         }
 601         FINISH_PTR_LIST(s_two);
 602         FINISH_PTR_LIST(s_one);
 603
 604         del_slist(slist);
 605         *slist = results;
 606 }
 607
 608 /*
 609  * and_slist_stack() is basically the same as popping the top two slists,
 610  * overwriting the one with the other and pushing it back on the stack.
 611  * The difference is that it checks to see that a mutually exclusive
 612  * state isn't included in both stacks.  If smatch sees something like
 613  * "if (a && !a)" it prints a warning.
 614  */
 615 void and_slist_stack(struct state_list_stack **slist_stack)
 616 {
 617         struct sm_state *tmp;
 618         struct smatch_state *tmp_state;
 619         struct state_list *tmp_slist = pop_slist(slist_stack);
 620
 621         FOR_EACH_PTR(tmp_slist, tmp) {
 622                 tmp_state = get_state_stack(*slist_stack, tmp->name,
 623                                             tmp->owner, tmp->sym);
 624                 if (tmp_state && tmp_state != tmp->state) {
 625                         smatch_msg("mutually exclusive 'and' conditions states "
 626                                    "'%s': %s & %s.\n",
 627                                    tmp->name, show_state(tmp_state),
 628                                    show_state(tmp->state));
 629                         tmp->state = merge_states(tmp->name, tmp->owner,
 630                                                   tmp->sym, tmp->state,
 631                                                   tmp_state);
 632                 }
 633                 set_state_stack(slist_stack, tmp->name, tmp->owner, tmp->sym,
 634                                 tmp->state);
 635         } END_FOR_EACH_PTR(tmp);
 636         del_slist(&tmp_slist);
 637 }
 638
 639 /*
 640  * or_slist_stack() is for if we have:  if (foo || bar) { foo->baz;
 641  * It pops the two slists from the top of the stack and merges them
 642  * together in a way that preserves the things they have in common
 643  * but creates a merged state for most of the rest.
 644  * You could have code that had:  if (foo || foo) { foo->baz;
 645  * It's this function which ensures smatch does the right thing.
 646  */
 647 void or_slist_stack(struct state_list_stack **slist_stack)
 648 {
 649         struct state_list *one;
 650         struct state_list *two;
 651         struct state_list *res = NULL;
 652         struct sm_state *tmp;
 653         struct sm_state *sm;
 654         struct sm_state *new_sm;
 655
 656         one = pop_slist(slist_stack);
 657         two = pop_slist(slist_stack);
 658
 659         FOR_EACH_PTR(one, tmp) {
 660                 sm = get_sm_state_slist(two, tmp->name, tmp->owner, tmp->sym);
 661                 new_sm = merge_sm_states(tmp, sm);
 662                 add_ptr_list(&res, new_sm);
 663         } END_FOR_EACH_PTR(tmp);
 664
 665         FOR_EACH_PTR(two, tmp) {
 666                 sm = get_sm_state_slist(one, tmp->name, tmp->owner, tmp->sym);
 667                 new_sm = merge_sm_states(tmp, sm);
 668                 add_ptr_list(&res, new_sm);
 669         } END_FOR_EACH_PTR(tmp);
 670
 671         push_slist(slist_stack, res);
 672
 673         del_slist(&one);
 674         del_slist(&two);
 675 }
 676
 677 /*
 678  * get_slist_from_named_stack() is only used for gotos.
 679  */
 680 struct state_list **get_slist_from_named_stack(struct named_stack *stack,
 681                                               const char *name)
 682 {
 683         struct named_slist *tmp;
 684
 685         FOR_EACH_PTR(stack, tmp) {
 686                 if (!strcmp(tmp->name, name))
 687                         return &tmp->slist;
 688         } END_FOR_EACH_PTR(tmp);
 689         return NULL;
 690 }
 691
 692 void overwrite_slist(struct state_list *from, struct state_list **to)
 693 {
 694         struct sm_state *tmp;
 695
 696         FOR_EACH_PTR(from, tmp) {
 697                 overwrite_sm_state(to, tmp);
 698         } END_FOR_EACH_PTR(tmp);
 699 }