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 if (!state1 || !state2)
 229                 ret = &undefined;
 230         else
 231                 ret = &merged;
 232         return ret;
 233 }
 234
 235 /*
 236  * add_pool() adds a slist to ->pools. If the slist has already been
 237  * added earlier then it doesn't get added a second time.
 238  */
 239 static void add_pool(struct sm_state *to, struct state_list *new)
 240 {
 241         struct state_list *tmp;
 242
 243         FOR_EACH_PTR(to->pools, tmp) {
 244                 if (tmp < new)
 245                         continue;
 246                 else if (tmp == new) {
 247                         return;
 248                 } else {
 249                         INSERT_CURRENT(new, tmp);
 250                         return;
 251                 }
 252         } END_FOR_EACH_PTR(tmp);
 253         add_ptr_list(&to->pools, new);
 254 }
 255
 256 static void copy_pools(struct sm_state *to, struct sm_state *sm)
 257 {
 258         struct state_list *tmp;
 259
 260         if (!sm)
 261                 return;
 262
 263         FOR_EACH_PTR(sm->pools, tmp) {
 264                 add_pool(to, tmp);
 265         } END_FOR_EACH_PTR(tmp);
 266 }
 267
 268 struct sm_state *merge_sm_states(struct sm_state *one, struct sm_state *two)
 269 {
 270         struct smatch_state *s;
 271         struct sm_state *result;
 272
 273         s = merge_states(one->name, one->owner, one->sym, one->state,
 274                         (two?two->state:NULL));
 275         result = alloc_state(one->name, one->owner, one->sym, s);
 276         add_possible(result, one);
 277         add_possible(result, two);
 278         copy_pools(result, one);
 279         copy_pools(result, two);
 280
 281         if (debug_states) {
 282                 struct sm_state *tmp;
 283                 int i = 0;
 284
 285                 printf("%d merge name='%s' owner=%d: %s + %s => %s (",
 286                         get_lineno(), one->name, one->owner,
 287                         show_state(one->state), show_state(two?two->state:NULL),
 288                         show_state(s));
 289
 290                 FOR_EACH_PTR(result->possible, tmp) {
 291                         if (i++) {
 292                                 printf(", ");
 293                         }
 294                         printf("%s", show_state(tmp->state));
 295                 } END_FOR_EACH_PTR(tmp);
 296                 printf(")\n");
 297         }
 298
 299         return result;
 300 }
 301
 302 struct sm_state *get_sm_state_slist(struct state_list *slist, const char *name,
 303                                 int owner, struct symbol *sym)
 304 {
 305         struct sm_state *state;
 306
 307         if (!name)
 308                 return NULL;
 309
 310         FOR_EACH_PTR(slist, state) {
 311                 if (state->owner == owner && state->sym == sym
 312                     && !strcmp(state->name, name))
 313                         return state;
 314         } END_FOR_EACH_PTR(state);
 315         return NULL;
 316 }
 317
 318 struct smatch_state *get_state_slist(struct state_list *slist,
 319                                 const char *name, int owner,
 320                                 struct symbol *sym)
 321 {
 322         struct sm_state *state;
 323
 324         state = get_sm_state_slist(slist, name, owner, sym);
 325         if (state)
 326                 return state->state;
 327         return NULL;
 328 }
 329
 330 static void overwrite_sm_state(struct state_list **slist,
 331                                struct sm_state *state)
 332 {
 333         struct sm_state *tmp;
 334         struct sm_state *new = clone_state(state); //fixme. why?
 335
 336         FOR_EACH_PTR(*slist, tmp) {
 337                 if (cmp_tracker(tmp, new) < 0)
 338                         continue;
 339                 else if (cmp_tracker(tmp, new) == 0) {
 340                         tmp->state = new->state;
 341                         tmp->pools = new->pools;
 342                         tmp->possible = new->possible;
 343                         __free_sm_state(new);
 344                         return;
 345                 } else {
 346                         INSERT_CURRENT(new, tmp);
 347                         return;
 348                 }
 349         } END_FOR_EACH_PTR(tmp);
 350         add_ptr_list(slist, new);
 351 }
 352
 353 void set_state_slist(struct state_list **slist, const char *name, int owner,
 354                      struct symbol *sym, struct smatch_state *state)
 355 {
 356         struct sm_state *tmp;
 357         struct sm_state *new = alloc_state(name, owner, sym, state);
 358
 359         FOR_EACH_PTR(*slist, tmp) {
 360                 if (cmp_tracker(tmp, new) < 0)
 361                         continue;
 362                 else if (cmp_tracker(tmp, new) == 0) {
 363                         tmp->state = state;
 364                         tmp->pools = NULL;
 365                         tmp->possible = NULL;
 366                         add_ptr_list(&tmp->possible, tmp);
 367                         __free_sm_state(new);
 368                         return;
 369                 } else {
 370                         INSERT_CURRENT(new, tmp);
 371                         return;
 372                 }
 373         } END_FOR_EACH_PTR(tmp);
 374         add_ptr_list(slist, new);
 375 }
 376
 377 void delete_state_slist(struct state_list **slist, const char *name, int owner,
 378                         struct symbol *sym)
 379 {
 380         struct sm_state *state;
 381
 382         FOR_EACH_PTR(*slist, state) {
 383                 if (state->owner == owner && state->sym == sym
 384                     && !strcmp(state->name, name)){
 385                         delete_ptr_list_entry((struct ptr_list **)slist,
 386                                               state, 1);
 387                         __free_sm_state(state);
 388                         return;
 389                 }
 390         } END_FOR_EACH_PTR(state);
 391 }
 392
 393
 394 void push_slist(struct state_list_stack **list_stack, struct state_list *slist)
 395 {
 396         add_ptr_list(list_stack, slist);
 397 }
 398
 399 struct state_list *pop_slist(struct state_list_stack **list_stack)
 400 {
 401         struct state_list *slist;
 402
 403         slist = last_ptr_list((struct ptr_list *)*list_stack);
 404         delete_ptr_list_last((struct ptr_list **)list_stack);
 405         return slist;
 406 }
 407
 408 void del_slist(struct state_list **slist)
 409 {
 410         __free_ptr_list((struct ptr_list **)slist);
 411 }
 412
 413 void del_slist_stack(struct state_list_stack **slist_stack)
 414 {
 415         struct state_list *slist;
 416
 417         FOR_EACH_PTR(*slist_stack, slist) {
 418                 __free_ptr_list((struct ptr_list **)&slist);
 419         } END_FOR_EACH_PTR(slist);
 420         __free_ptr_list((struct ptr_list **)slist_stack);
 421 }
 422
 423 /*
 424  * set_state_stack() sets the state for the top slist on the stack.
 425  */
 426 void set_state_stack(struct state_list_stack **stack, const char *name,
 427                      int owner, struct symbol *sym, struct smatch_state *state)
 428 {
 429         struct state_list *slist;
 430
 431         slist = pop_slist(stack);
 432         set_state_slist(&slist, name, owner, sym, state);
 433         push_slist(stack, slist);
 434 }
 435
 436 /*
 437  * get_state_stack() gets the state for the top slist on the stack.
 438  */
 439 struct smatch_state *get_state_stack(struct state_list_stack *stack,
 440                                      const char *name, int owner,
 441                                      struct symbol *sym)
 442 {
 443         struct state_list *slist;
 444         struct smatch_state *ret;
 445
 446         slist = pop_slist(&stack);
 447         ret = get_state_slist(slist, name, owner, sym);
 448         push_slist(&stack, slist);
 449         return ret;
 450 }
 451
 452 /*
 453  * merge_slist() is called whenever paths merge, such as after
 454  * an if statement.  It takes the two slists and creates one.
 455  */
 456 void merge_slist(struct state_list **to, struct state_list *slist)
 457 {
 458         struct sm_state *to_state, *state, *tmp;
 459         struct state_list *results = NULL;
 460         struct state_list *implied_to = NULL;
 461         struct state_list *implied_from = NULL;
 462
 463 #ifdef CHECKORDER
 464         check_order(*to);
 465         check_order(slist);
 466 #endif
 467
 468         /* merging a null and nonnull path gives you only the nonnull path */
 469         if (!slist) {
 470                 return;
 471         }
 472         if (!*to) {
 473                 *to = clone_slist(slist);
 474                 return;
 475         }
 476
 477         implied_to = clone_slist(*to);
 478         implied_from = clone_slist(slist);
 479
 480         PREPARE_PTR_LIST(*to, to_state);
 481         PREPARE_PTR_LIST(slist, state);
 482         for (;;) {
 483                 if (!to_state && !state)
 484                         break;
 485                 if (cmp_tracker(to_state, state) < 0) {
 486                         tmp = merge_sm_states(to_state, NULL);
 487                         add_pool(tmp, implied_to);
 488                         add_ptr_list(&results, tmp);
 489                         NEXT_PTR_LIST(to_state);
 490                 } else if (cmp_tracker(to_state, state) == 0) {
 491                         tmp = merge_sm_states(to_state, state);
 492                         add_pool(tmp, implied_to);
 493                         add_pool(tmp, implied_from);
 494                         add_ptr_list(&results, tmp);
 495                         NEXT_PTR_LIST(to_state);
 496                         NEXT_PTR_LIST(state);
 497                 } else {
 498                         tmp = merge_sm_states(state, NULL);
 499                         add_pool(tmp, implied_from);
 500                         add_ptr_list(&results, tmp);
 501                         NEXT_PTR_LIST(state);
 502                 }
 503         }
 504         FINISH_PTR_LIST(state);
 505         FINISH_PTR_LIST(to_state);
 506
 507         del_slist(to);
 508         *to = results;
 509
 510         push_slist(&implied_pools, implied_from);
 511         push_slist(&implied_pools, implied_to);
 512 }
 513
 514 /*
 515  * is_currently_in_pool() is used because we remove states from pools.
 516  * When set_state() is called then we set ->pools to NULL, but on
 517  * other paths the state is still a member of those pools.
 518  * Confusing huh?
 519  * if (foo) {
 520  *        bar = 1;
 521  *        a = malloc();
 522  * }
 523  * if (!a)
 524  *        return;
 525  * if (bar)
 526  *        a->b = x;
 527  */
 528 static int is_currently_in_pool(struct sm_state *sm, struct state_list *pool,
 529                         struct state_list *cur_slist)
 530 {
 531         struct sm_state *cur_state;
 532         struct state_list *tmp;
 533
 534         cur_state = get_sm_state_slist(cur_slist, sm->name, sm->owner, sm->sym);
 535         if (!cur_state)
 536                 return 0;
 537
 538         FOR_EACH_PTR(cur_state->pools, tmp) {
 539                 if (tmp == pool)
 540                         return 1;
 541         } END_FOR_EACH_PTR(tmp);
 542         return 0;
 543 }
 544
 545 struct state_list *clone_states_in_pool(struct state_list *pool,
 546                                 struct state_list *cur_slist)
 547 {
 548         struct sm_state *state;
 549         struct sm_state *tmp;
 550         struct state_list *to_slist = NULL;
 551
 552         FOR_EACH_PTR(pool, state) {
 553                 if (is_currently_in_pool(state, pool, cur_slist)) {
 554                         tmp = clone_state(state);
 555                         add_ptr_list(&to_slist, tmp);
 556                 }
 557         } END_FOR_EACH_PTR(state);
 558 #ifdef CHECKORDER
 559         check_order(to_slist);
 560 #endif
 561         return to_slist;
 562 }
 563
 564 /*
 565  * filter() is used to find what states are the same across
 566  * a series of slists.
 567  * It takes a **slist and a *filter.
 568  * It removes everything from **slist that isn't in *filter.
 569  * The reason you would want to do this is if you want to
 570  * know what other states are true if one state is true.  (smatch_implied).
 571  */
 572 void filter(struct state_list **slist, struct state_list *filter,
 573         struct state_list *cur_slist)
 574 {
 575         struct sm_state *s_one, *s_two;
 576         struct state_list *results = NULL;
 577
 578 #ifdef CHECKORDER
 579         check_order(*slist);
 580         check_order(filter);
 581 #endif
 582
 583         PREPARE_PTR_LIST(*slist, s_one);
 584         PREPARE_PTR_LIST(filter, s_two);
 585         for (;;) {
 586                 if (!s_one || !s_two)
 587                         break;
 588                 if (cmp_tracker(s_one, s_two) < 0) {
 589                         NEXT_PTR_LIST(s_one);
 590                 } else if (cmp_tracker(s_one, s_two) == 0) {
 591                         /* todo.  pointer comparison works fine for most things
 592                            except smatch_extra.  we may need a hook here. */
 593                         if (s_one->state == s_two->state &&
 594                                 is_currently_in_pool(s_two, filter, cur_slist)) {
 595                                 add_ptr_list(&results, s_one);
 596                         }
 597                         NEXT_PTR_LIST(s_one);
 598                         NEXT_PTR_LIST(s_two);
 599                 } else {
 600                         NEXT_PTR_LIST(s_two);
 601                 }
 602         }
 603         FINISH_PTR_LIST(s_two);
 604         FINISH_PTR_LIST(s_one);
 605
 606         del_slist(slist);
 607         *slist = results;
 608 }
 609
 610 /*
 611  * and_slist_stack() is basically the same as popping the top two slists,
 612  * overwriting the one with the other and pushing it back on the stack.
 613  * The difference is that it checks to see that a mutually exclusive
 614  * state isn't included in both stacks.  If smatch sees something like
 615  * "if (a && !a)" it prints a warning.
 616  */
 617 void and_slist_stack(struct state_list_stack **slist_stack)
 618 {
 619         struct sm_state *tmp;
 620         struct smatch_state *tmp_state;
 621         struct state_list *tmp_slist = pop_slist(slist_stack);
 622
 623         FOR_EACH_PTR(tmp_slist, tmp) {
 624                 tmp_state = get_state_stack(*slist_stack, tmp->name,
 625                                             tmp->owner, tmp->sym);
 626                 if (tmp_state && tmp_state != tmp->state) {
 627                         struct smatch_state *s;
 628
 629                         s = merge_states(tmp->name, tmp->owner, tmp->sym,
 630                                         tmp->state, tmp_state);
 631                         smatch_msg("mutually exclusive 'and' conditions states "
 632                                 "'%s': %s + %s => %s",
 633                                 tmp->name, show_state(tmp_state),
 634                                 show_state(tmp->state), show_state(s));
 635                         tmp->state = s;
 636
 637                 }
 638                 set_state_stack(slist_stack, tmp->name, tmp->owner, tmp->sym,
 639                                 tmp->state);
 640         } END_FOR_EACH_PTR(tmp);
 641         del_slist(&tmp_slist);
 642 }
 643
 644 /*
 645  * or_slist_stack() is for if we have:  if (foo || bar) { foo->baz;
 646  * It pops the two slists from the top of the stack and merges them
 647  * together in a way that preserves the things they have in common
 648  * but creates a merged state for most of the rest.
 649  * You could have code that had:  if (foo || foo) { foo->baz;
 650  * It's this function which ensures smatch does the right thing.
 651  */
 652 void or_slist_stack(struct state_list_stack **slist_stack)
 653 {
 654         struct state_list *one;
 655         struct state_list *two;
 656         struct state_list *res = NULL;
 657         struct sm_state *tmp;
 658         struct sm_state *sm;
 659         struct sm_state *new_sm;
 660
 661         one = pop_slist(slist_stack);
 662         two = pop_slist(slist_stack);
 663
 664         FOR_EACH_PTR(one, tmp) {
 665                 sm = get_sm_state_slist(two, tmp->name, tmp->owner, tmp->sym);
 666                 new_sm = merge_sm_states(tmp, sm);
 667                 add_ptr_list(&res, new_sm);
 668         } END_FOR_EACH_PTR(tmp);
 669
 670         FOR_EACH_PTR(two, tmp) {
 671                 sm = get_sm_state_slist(one, tmp->name, tmp->owner, tmp->sym);
 672                 new_sm = merge_sm_states(tmp, sm);
 673                 add_ptr_list(&res, new_sm);
 674         } END_FOR_EACH_PTR(tmp);
 675
 676         push_slist(slist_stack, res);
 677
 678         del_slist(&one);
 679         del_slist(&two);
 680 }
 681
 682 /*
 683  * get_slist_from_named_stack() is only used for gotos.
 684  */
 685 struct state_list **get_slist_from_named_stack(struct named_stack *stack,
 686                                               const char *name)
 687 {
 688         struct named_slist *tmp;
 689
 690         FOR_EACH_PTR(stack, tmp) {
 691                 if (!strcmp(tmp->name, name))
 692                         return &tmp->slist;
 693         } END_FOR_EACH_PTR(tmp);
 694         return NULL;
 695 }
 696
 697 void overwrite_slist(struct state_list *from, struct state_list **to)
 698 {
 699         struct sm_state *tmp;
 700
 701         FOR_EACH_PTR(from, tmp) {
 702                 overwrite_sm_state(to, tmp);
 703         } END_FOR_EACH_PTR(tmp);
 704 }