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_slist.h"
  14
  15 #undef CHECKORDER
  16
  17 ALLOCATOR(smatch_state, "smatch state");
  18 ALLOCATOR(sm_state, "sm state");
  19 ALLOCATOR(named_slist, "named slist");
  20 __DO_ALLOCATOR(char, 1, 4, "state names", sname);
  21
  22 static int sm_state_counter;
  23
  24 char *show_sm(struct sm_state *sm)
  25 {
  26         static char buf[256];
  27         struct sm_state *tmp;
  28         int pos;
  29         int i;
  30
  31         pos = snprintf(buf, sizeof(buf), "[%s] '%s' = %s (",
  32                        check_name(sm->owner), sm->name, show_state(sm->state));
  33         if (pos > sizeof(buf))
  34                 goto truncate;
  35
  36         i = 0;
  37         FOR_EACH_PTR(sm->possible, tmp) {
  38                 if (i++)
  39                         pos += snprintf(buf + pos, sizeof(buf) - pos, ", ");
  40                 if (pos > sizeof(buf))
  41                         goto truncate;
  42                 pos += snprintf(buf + pos, sizeof(buf) - pos, "%s",
  43                                show_state(tmp->state));
  44                 if (pos > sizeof(buf))
  45                         goto truncate;
  46         } END_FOR_EACH_PTR(tmp);
  47         snprintf(buf + pos, sizeof(buf) - pos, ")");
  48
  49         return buf;
  50
  51 truncate:
  52         for (i = 0; i < 3; i++)
  53                 buf[sizeof(buf) - 2 - i] = '.';
  54         return buf;
  55 }
  56
  57 void __print_slist(struct state_list *slist)
  58 {
  59         struct sm_state *sm;
  60
  61         printf("dumping slist at %d\n", get_lineno());
  62         FOR_EACH_PTR(slist, sm) {
  63                 printf("%s\n", show_sm(sm));
  64         } END_FOR_EACH_PTR(sm);
  65         printf("---\n");
  66 }
  67
  68 /* NULL states go at the end to simplify merge_slist */
  69 int cmp_tracker(const struct sm_state *a, const struct sm_state *b)
  70 {
  71         int ret;
  72
  73         if (a == b)
  74                 return 0;
  75         if (!b)
  76                 return -1;
  77         if (!a)
  78                 return 1;
  79
  80         if (a->owner > b->owner)
  81                 return -1;
  82         if (a->owner < b->owner)
  83                 return 1;
  84
  85         ret = strcmp(a->name, b->name);
  86         if (ret)
  87                 return ret;
  88
  89         if (!b->sym && a->sym)
  90                 return -1;
  91         if (!a->sym && b->sym)
  92                 return 1;
  93         if (a->sym > b->sym)
  94                 return -1;
  95         if (a->sym < b->sym)
  96                 return 1;
  97
  98         return 0;
  99 }
 100
 101 static int cmp_sm_states(const struct sm_state *a, const struct sm_state *b)
 102 {
 103         int ret;
 104
 105         ret = cmp_tracker(a, b);
 106         if (ret)
 107                 return ret;
 108
 109         /* todo:  add hook for smatch_extra.c */
 110         if (a->state > b->state)
 111                 return -1;
 112         if (a->state < b->state)
 113                 return 1;
 114         return 0;
 115 }
 116
 117 static struct sm_state *alloc_sm_state(int owner, const char *name,
 118                              struct symbol *sym, struct smatch_state *state)
 119 {
 120         struct sm_state *sm_state = __alloc_sm_state(0);
 121
 122         sm_state_counter++;
 123
 124         sm_state->name = alloc_sname(name);
 125         sm_state->owner = owner;
 126         sm_state->sym = sym;
 127         sm_state->state = state;
 128         sm_state->line = get_lineno();
 129         sm_state->merged = 0;
 130         sm_state->implied = 0;
 131         sm_state->pool = NULL;
 132         sm_state->left = NULL;
 133         sm_state->right = NULL;
 134         sm_state->nr_children = 1;
 135         sm_state->possible = NULL;
 136         add_ptr_list(&sm_state->possible, sm_state);
 137         return sm_state;
 138 }
 139
 140 static struct sm_state *alloc_state_no_name(int owner, const char *name,
 141                                      struct symbol *sym,
 142                                      struct smatch_state *state)
 143 {
 144         struct sm_state *tmp;
 145
 146         tmp = alloc_sm_state(owner, NULL, sym, state);
 147         tmp->name = name;
 148         return tmp;
 149 }
 150
 151 void add_sm_state_slist(struct state_list **slist, struct sm_state *new)
 152 {
 153         struct sm_state *tmp;
 154
 155         FOR_EACH_PTR(*slist, tmp) {
 156                 if (cmp_sm_states(tmp, new) < 0)
 157                         continue;
 158                 else if (cmp_sm_states(tmp, new) == 0) {
 159                         return;
 160                 } else {
 161                         INSERT_CURRENT(new, tmp);
 162                         return;
 163                 }
 164         } END_FOR_EACH_PTR(tmp);
 165         add_ptr_list(slist, new);
 166 }
 167
 168 static void copy_possibles(struct sm_state *to, struct sm_state *from)
 169 {
 170         struct sm_state *tmp;
 171
 172         FOR_EACH_PTR(from->possible, tmp) {
 173                 add_sm_state_slist(&to->possible, tmp);
 174         } END_FOR_EACH_PTR(tmp);
 175 }
 176
 177 char *alloc_sname(const char *str)
 178 {
 179         char *tmp;
 180
 181         if (!str)
 182                 return NULL;
 183         tmp = __alloc_sname(strlen(str) + 1);
 184         strcpy(tmp, str);
 185         return tmp;
 186 }
 187
 188 int out_of_memory()
 189 {
 190         /*
 191          * I decided to use 50M here based on trial and error.
 192          * It works out OK for the kernel and so it should work
 193          * for most other projects as well.
 194          */
 195         if (sm_state_counter * sizeof(struct sm_state) >= 50000000)
 196                 return 1;
 197         return 0;
 198 }
 199
 200 static void free_sm_state(struct sm_state *sm)
 201 {
 202         free_slist(&sm->possible);
 203         /*
 204          * fixme.  Free the actual state.
 205          * Right now we leave it until the end of the function
 206          * because we don't want to double free it.
 207          * Use the freelist to not double free things
 208          */
 209 }
 210
 211 static void free_all_sm_states(struct allocation_blob *blob)
 212 {
 213         unsigned int size = sizeof(struct sm_state);
 214         unsigned int offset = 0;
 215
 216         while (offset < blob->offset) {
 217                 free_sm_state((struct sm_state *)(blob->data + offset));
 218                 offset += size;
 219         }
 220 }
 221
 222 /* At the end of every function we free all the sm_states */
 223 void free_every_single_sm_state(void)
 224 {
 225         struct allocator_struct *desc = &sm_state_allocator;
 226         struct allocation_blob *blob = desc->blobs;
 227
 228         desc->blobs = NULL;
 229         desc->allocations = 0;
 230         desc->total_bytes = 0;
 231         desc->useful_bytes = 0;
 232         desc->freelist = NULL;
 233         while (blob) {
 234                 struct allocation_blob *next = blob->next;
 235                 free_all_sm_states(blob);
 236                 blob_free(blob, desc->chunking);
 237                 blob = next;
 238         }
 239         clear_sname_alloc();
 240
 241         sm_state_counter = 0;
 242 }
 243
 244 struct sm_state *clone_sm(struct sm_state *s)
 245 {
 246         struct sm_state *ret;
 247
 248         ret = alloc_state_no_name(s->owner, s->name, s->sym, s->state);
 249         ret->merged = s->merged;
 250         ret->implied = s->implied;
 251         ret->line = s->line;
 252         /* clone_sm() doesn't copy the pools.  Each state needs to have
 253            only one pool. */
 254         ret->possible = clone_slist(s->possible);
 255         ret->left = s->left;
 256         ret->right = s->right;
 257         ret->nr_children = s->nr_children;
 258         return ret;
 259 }
 260
 261 int is_merged(struct sm_state *sm)
 262 {
 263         return sm->merged;
 264 }
 265
 266 int is_implied(struct sm_state *sm)
 267 {
 268         return sm->implied;
 269 }
 270
 271 int slist_has_state(struct state_list *slist, struct smatch_state *state)
 272 {
 273         struct sm_state *tmp;
 274
 275         FOR_EACH_PTR(slist, tmp) {
 276                 if (tmp->state == state)
 277                         return 1;
 278         } END_FOR_EACH_PTR(tmp);
 279         return 0;
 280 }
 281
 282 static void check_order(struct state_list *slist)
 283 {
 284 #ifdef CHECKORDER
 285         struct sm_state *sm;
 286         struct sm_state *last = NULL;
 287         int printed = 0;
 288
 289         FOR_EACH_PTR(slist, sm) {
 290                 if (last && cmp_tracker(sm, last) <= 0) {
 291                         printf("Error.  Unsorted slist %d vs %d, %p vs %p, "
 292                                "%s vs %s\n", last->owner, sm->owner,
 293                                last->sym, sm->sym, last->name, sm->name);
 294                         printed = 1;
 295                 }
 296                 last = sm;
 297         } END_FOR_EACH_PTR(sm);
 298
 299         if (printed)
 300                 printf("======\n");
 301 #endif
 302 }
 303
 304 struct state_list *clone_slist(struct state_list *from_slist)
 305 {
 306         struct sm_state *sm;
 307         struct state_list *to_slist = NULL;
 308
 309         FOR_EACH_PTR(from_slist, sm) {
 310                 add_ptr_list(&to_slist, sm);
 311         } END_FOR_EACH_PTR(sm);
 312         return to_slist;
 313 }
 314
 315 struct state_list_stack *clone_stack(struct state_list_stack *from_stack)
 316 {
 317         struct state_list *slist;
 318         struct state_list_stack *to_stack = NULL;
 319
 320         FOR_EACH_PTR(from_stack, slist) {
 321                 push_slist(&to_stack, slist);
 322         } END_FOR_EACH_PTR(slist);
 323         return to_stack;
 324 }
 325
 326 struct smatch_state *merge_states(int owner, const char *name,
 327                                   struct symbol *sym,
 328                                   struct smatch_state *state1,
 329                                   struct smatch_state *state2)
 330 {
 331         struct smatch_state *ret;
 332
 333         if (state1 == state2)
 334                 ret = state1;
 335         else if (__has_merge_function(owner))
 336                 ret = __client_merge_function(owner, state1, state2);
 337         else if (!state1 || !state2)
 338                 ret = &undefined;
 339         else
 340                 ret = &merged;
 341         return ret;
 342 }
 343
 344 struct sm_state *merge_sm_states(struct sm_state *one, struct sm_state *two)
 345 {
 346         struct smatch_state *s;
 347         struct sm_state *result;
 348
 349         if (one == two)
 350                 return one;
 351         s = merge_states(one->owner, one->name, one->sym, one->state, two->state);
 352         result = alloc_state_no_name(one->owner, one->name, one->sym, s);
 353         result->merged = 1;
 354         result->left = one;
 355         result->right = two;
 356         result->nr_children = one->nr_children + two->nr_children;
 357         copy_possibles(result, one);
 358         copy_possibles(result, two);
 359
 360         if (option_debug) {
 361                 struct sm_state *tmp;
 362                 int i = 0;
 363
 364                 printf("%d merge [%s] '%s' %s(L %d) + %s(L %d) => %s (",
 365                         get_lineno(), check_name(one->owner), one->name,
 366                         show_state(one->state), one->line,
 367                         show_state(two->state), two->line,
 368                         show_state(s));
 369
 370                 FOR_EACH_PTR(result->possible, tmp) {
 371                         if (i++)
 372                                 printf(", ");
 373                         printf("%s", show_state(tmp->state));
 374                 } END_FOR_EACH_PTR(tmp);
 375                 printf(")\n");
 376         }
 377
 378         return result;
 379 }
 380
 381 struct sm_state *get_sm_state_slist(struct state_list *slist, int owner, const char *name,
 382                                 struct symbol *sym)
 383 {
 384         struct sm_state *sm;
 385
 386         if (!name)
 387                 return NULL;
 388
 389         FOR_EACH_PTR(slist, sm) {
 390                 if (sm->owner == owner && sm->sym == sym && !strcmp(sm->name, name))
 391                         return sm;
 392         } END_FOR_EACH_PTR(sm);
 393         return NULL;
 394 }
 395
 396 struct smatch_state *get_state_slist(struct state_list *slist,
 397                                 int owner, const char *name,
 398                                 struct symbol *sym)
 399 {
 400         struct sm_state *sm;
 401
 402         sm = get_sm_state_slist(slist, owner, name, sym);
 403         if (sm)
 404                 return sm->state;
 405         return NULL;
 406 }
 407
 408 void overwrite_sm_state(struct state_list **slist, struct sm_state *new)
 409 {
 410         struct sm_state *tmp;
 411
 412         FOR_EACH_PTR(*slist, tmp) {
 413                 if (cmp_tracker(tmp, new) < 0)
 414                         continue;
 415                 else if (cmp_tracker(tmp, new) == 0) {
 416                         REPLACE_CURRENT_PTR(tmp, new);
 417                         return;
 418                 } else {
 419                         INSERT_CURRENT(new, tmp);
 420                         return;
 421                 }
 422         } END_FOR_EACH_PTR(tmp);
 423         add_ptr_list(slist, new);
 424 }
 425
 426 void overwrite_sm_state_stack(struct state_list_stack **stack,
 427                         struct sm_state *sm)
 428 {
 429         struct state_list *slist;
 430
 431         slist = pop_slist(stack);
 432         overwrite_sm_state(&slist, sm);
 433         push_slist(stack, slist);
 434 }
 435
 436 struct sm_state *set_state_slist(struct state_list **slist, int owner, const char *name,
 437                      struct symbol *sym, struct smatch_state *state)
 438 {
 439         struct sm_state *tmp;
 440         struct sm_state *new = alloc_sm_state(owner, name, sym, state);
 441
 442         FOR_EACH_PTR(*slist, tmp) {
 443                 if (cmp_tracker(tmp, new) < 0)
 444                         continue;
 445                 else if (cmp_tracker(tmp, new) == 0) {
 446                         REPLACE_CURRENT_PTR(tmp, new);
 447                         return new;
 448                 } else {
 449                         INSERT_CURRENT(new, tmp);
 450                         return new;
 451                 }
 452         } END_FOR_EACH_PTR(tmp);
 453         add_ptr_list(slist, new);
 454         return new;
 455 }
 456
 457 void delete_state_slist(struct state_list **slist, int owner, const char *name,
 458                         struct symbol *sym)
 459 {
 460         struct sm_state *sm;
 461
 462         FOR_EACH_PTR(*slist, sm) {
 463                 if (sm->owner == owner && sm->sym == sym && !strcmp(sm->name, name)) {
 464                         DELETE_CURRENT_PTR(sm);
 465                         return;
 466                 }
 467         } END_FOR_EACH_PTR(sm);
 468 }
 469
 470 void delete_state_stack(struct state_list_stack **stack, int owner, const char *name,
 471                         struct symbol *sym)
 472 {
 473         struct state_list *slist;
 474
 475         slist = pop_slist(stack);
 476         delete_state_slist(&slist, owner, name, sym);
 477         push_slist(stack, slist);
 478 }
 479
 480 void push_slist(struct state_list_stack **list_stack, struct state_list *slist)
 481 {
 482         add_ptr_list(list_stack, slist);
 483 }
 484
 485 struct state_list *pop_slist(struct state_list_stack **list_stack)
 486 {
 487         struct state_list *slist;
 488
 489         slist = last_ptr_list((struct ptr_list *)*list_stack);
 490         delete_ptr_list_last((struct ptr_list **)list_stack);
 491         return slist;
 492 }
 493
 494 void free_slist(struct state_list **slist)
 495 {
 496         __free_ptr_list((struct ptr_list **)slist);
 497 }
 498
 499 void free_stack(struct state_list_stack **stack)
 500 {
 501         __free_ptr_list((struct ptr_list **)stack);
 502 }
 503
 504 void free_stack_and_slists(struct state_list_stack **slist_stack)
 505 {
 506         struct state_list *slist;
 507
 508         FOR_EACH_PTR(*slist_stack, slist) {
 509                 free_slist(&slist);
 510         } END_FOR_EACH_PTR(slist);
 511         free_stack(slist_stack);
 512 }
 513
 514 /*
 515  * set_state_stack() sets the state for the top slist on the stack.
 516  */
 517 struct sm_state *set_state_stack(struct state_list_stack **stack, int owner, const char *name,
 518                                 struct symbol *sym, struct smatch_state *state)
 519 {
 520         struct state_list *slist;
 521         struct sm_state *sm;
 522
 523         slist = pop_slist(stack);
 524         sm = set_state_slist(&slist, owner, name, sym, state);
 525         push_slist(stack, slist);
 526
 527         return sm;
 528 }
 529
 530 /*
 531  * get_sm_state_stack() gets the state for the top slist on the stack.
 532  */
 533 struct sm_state *get_sm_state_stack(struct state_list_stack *stack,
 534                                 int owner, const char *name,
 535                                 struct symbol *sym)
 536 {
 537         struct state_list *slist;
 538         struct sm_state *ret;
 539
 540         slist = pop_slist(&stack);
 541         ret = get_sm_state_slist(slist, owner, name, sym);
 542         push_slist(&stack, slist);
 543         return ret;
 544 }
 545
 546 struct smatch_state *get_state_stack(struct state_list_stack *stack,
 547                                 int owner, const char *name,
 548                                 struct symbol *sym)
 549 {
 550         struct sm_state *sm;
 551
 552         sm = get_sm_state_stack(stack, owner, name, sym);
 553         if (sm)
 554                 return sm->state;
 555         return NULL;
 556 }
 557
 558 static void match_states(struct state_list **one, struct state_list **two)
 559 {
 560         struct sm_state *one_sm;
 561         struct sm_state *two_sm;
 562         struct sm_state *tmp;
 563         struct smatch_state *tmp_state;
 564         struct state_list *add_to_one = NULL;
 565         struct state_list *add_to_two = NULL;
 566
 567         PREPARE_PTR_LIST(*one, one_sm);
 568         PREPARE_PTR_LIST(*two, two_sm);
 569         for (;;) {
 570                 if (!one_sm && !two_sm)
 571                         break;
 572                 if (cmp_tracker(one_sm, two_sm) < 0) {
 573                         tmp_state = __client_unmatched_state_function(one_sm);
 574                         tmp = alloc_state_no_name(one_sm->owner, one_sm->name,
 575                                                   one_sm->sym, tmp_state);
 576                         add_ptr_list(&add_to_two, tmp);
 577                         NEXT_PTR_LIST(one_sm);
 578                 } else if (cmp_tracker(one_sm, two_sm) == 0) {
 579                         NEXT_PTR_LIST(one_sm);
 580                         NEXT_PTR_LIST(two_sm);
 581                 } else {
 582                         tmp_state = __client_unmatched_state_function(two_sm);
 583                         tmp = alloc_state_no_name(two_sm->owner, two_sm->name,
 584                                                   two_sm->sym, tmp_state);
 585                         add_ptr_list(&add_to_one, tmp);
 586                         NEXT_PTR_LIST(two_sm);
 587                 }
 588         }
 589         FINISH_PTR_LIST(two_sm);
 590         FINISH_PTR_LIST(one_sm);
 591
 592         overwrite_slist(add_to_one, one);
 593         overwrite_slist(add_to_two, two);
 594 }
 595
 596 static void clone_pool_havers(struct state_list *slist)
 597 {
 598         struct sm_state *sm;
 599         struct sm_state *new;
 600
 601         FOR_EACH_PTR(slist, sm) {
 602                 if (sm->pool) {
 603                         new = clone_sm(sm);
 604                         REPLACE_CURRENT_PTR(sm, new);
 605                 }
 606         } END_FOR_EACH_PTR(sm);
 607 }
 608
 609 int __slist_id;
 610 /*
 611  * Sets the first state to the slist_id.
 612  */
 613 static void set_slist_id(struct state_list *slist)
 614 {
 615         struct smatch_state *state;
 616         struct sm_state *tmp, *new;
 617
 618         state = alloc_state_num(++__slist_id);
 619         new = alloc_sm_state(-1, "unnull_path", NULL, state);
 620
 621         FOR_EACH_PTR(slist, tmp) {
 622                 if (tmp->owner != (unsigned short)-1)
 623                         return;
 624                 REPLACE_CURRENT_PTR(tmp, new);
 625                 return;
 626         } END_FOR_EACH_PTR(tmp);
 627 }
 628
 629 int get_slist_id(struct state_list *slist)
 630 {
 631         struct sm_state *tmp;
 632
 633         FOR_EACH_PTR(slist, tmp) {
 634                 if (tmp->owner != (unsigned short)-1)
 635                         return 0;
 636                 return PTR_INT(tmp->state->data);
 637         } END_FOR_EACH_PTR(tmp);
 638         return 0;
 639 }
 640
 641 /*
 642  * merge_slist() is called whenever paths merge, such as after
 643  * an if statement.  It takes the two slists and creates one.
 644  */
 645 void merge_slist(struct state_list **to, struct state_list *slist)
 646 {
 647         struct sm_state *one_sm, *two_sm, *tmp;
 648         struct state_list *results = NULL;
 649         struct state_list *implied_one = NULL;
 650         struct state_list *implied_two = NULL;
 651
 652         if (out_of_memory())
 653                 return;
 654
 655         check_order(*to);
 656         check_order(slist);
 657
 658         /* merging a null and nonnull path gives you only the nonnull path */
 659         if (!slist)
 660                 return;
 661
 662         if (!*to) {
 663                 *to = clone_slist(slist);
 664                 return;
 665         }
 666
 667         implied_one = clone_slist(*to);
 668         implied_two = clone_slist(slist);
 669
 670         match_states(&implied_one, &implied_two);
 671
 672         clone_pool_havers(implied_one);
 673         clone_pool_havers(implied_two);
 674
 675         set_slist_id(implied_one);
 676         set_slist_id(implied_two);
 677
 678         PREPARE_PTR_LIST(implied_one, one_sm);
 679         PREPARE_PTR_LIST(implied_two, two_sm);
 680         for (;;) {
 681                 if (!one_sm && !two_sm)
 682                         break;
 683                 if (cmp_tracker(one_sm, two_sm) < 0) {
 684                         sm_msg("error:  Internal smatch error.");
 685                         NEXT_PTR_LIST(one_sm);
 686                 } else if (cmp_tracker(one_sm, two_sm) == 0) {
 687                         if (one_sm != two_sm) {
 688                                 one_sm->pool = implied_one;
 689                                 two_sm->pool = implied_two;
 690                         }
 691
 692                         tmp = merge_sm_states(one_sm, two_sm);
 693                         add_ptr_list(&results, tmp);
 694                         NEXT_PTR_LIST(one_sm);
 695                         NEXT_PTR_LIST(two_sm);
 696                 } else {
 697                         sm_msg("error:  Internal smatch error.");
 698                         NEXT_PTR_LIST(two_sm);
 699                 }
 700         }
 701         FINISH_PTR_LIST(two_sm);
 702         FINISH_PTR_LIST(one_sm);
 703
 704         free_slist(to);
 705         *to = results;
 706 }
 707
 708 /*
 709  * filter_slist() removes any sm states "slist" holds in common with "filter"
 710  */
 711 void filter_slist(struct state_list **slist, struct state_list *filter)
 712 {
 713         struct sm_state *one_sm, *two_sm;
 714         struct state_list *results = NULL;
 715
 716         PREPARE_PTR_LIST(*slist, one_sm);
 717         PREPARE_PTR_LIST(filter, two_sm);
 718         for (;;) {
 719                 if (!one_sm && !two_sm)
 720                         break;
 721                 if (cmp_tracker(one_sm, two_sm) < 0) {
 722                         add_ptr_list(&results, one_sm);
 723                         NEXT_PTR_LIST(one_sm);
 724                 } else if (cmp_tracker(one_sm, two_sm) == 0) {
 725                         if (one_sm != two_sm)
 726                                 add_ptr_list(&results, one_sm);
 727                         NEXT_PTR_LIST(one_sm);
 728                         NEXT_PTR_LIST(two_sm);
 729                 } else {
 730                         NEXT_PTR_LIST(two_sm);
 731                 }
 732         }
 733         FINISH_PTR_LIST(two_sm);
 734         FINISH_PTR_LIST(one_sm);
 735
 736         free_slist(slist);
 737         *slist = results;
 738 }
 739
 740 /*
 741  * and_slist_stack() pops the top two slists, overwriting the one with
 742  * the other and pushing it back on the stack.
 743  */
 744 void and_slist_stack(struct state_list_stack **slist_stack)
 745 {
 746         struct sm_state *tmp;
 747         struct state_list *right_slist = pop_slist(slist_stack);
 748
 749         FOR_EACH_PTR(right_slist, tmp) {
 750                 overwrite_sm_state_stack(slist_stack, tmp);
 751         } END_FOR_EACH_PTR(tmp);
 752         free_slist(&right_slist);
 753 }
 754
 755 /*
 756  * or_slist_stack() is for if we have:  if (foo || bar) { foo->baz;
 757  * It pops the two slists from the top of the stack and merges them
 758  * together in a way that preserves the things they have in common
 759  * but creates a merged state for most of the rest.
 760  * You could have code that had:  if (foo || foo) { foo->baz;
 761  * It's this function which ensures smatch does the right thing.
 762  */
 763 void or_slist_stack(struct state_list_stack **pre_conds,
 764                     struct state_list *cur_slist,
 765                     struct state_list_stack **slist_stack)
 766 {
 767         struct state_list *new;
 768         struct state_list *old;
 769         struct state_list *pre_slist;
 770         struct state_list *res;
 771         struct state_list *tmp_slist;
 772
 773         new = pop_slist(slist_stack);
 774         old = pop_slist(slist_stack);
 775
 776         pre_slist = pop_slist(pre_conds);
 777         push_slist(pre_conds, clone_slist(pre_slist));
 778
 779         res = clone_slist(pre_slist);
 780         overwrite_slist(old, &res);
 781
 782         tmp_slist = clone_slist(cur_slist);
 783         overwrite_slist(new, &tmp_slist);
 784
 785         merge_slist(&res, tmp_slist);
 786         filter_slist(&res, pre_slist);
 787
 788         push_slist(slist_stack, res);
 789         free_slist(&tmp_slist);
 790         free_slist(&pre_slist);
 791         free_slist(&new);
 792         free_slist(&old);
 793 }
 794
 795 /*
 796  * get_slist_from_named_stack() is only used for gotos.
 797  */
 798 struct state_list **get_slist_from_named_stack(struct named_stack *stack,
 799                                               const char *name)
 800 {
 801         struct named_slist *tmp;
 802
 803         FOR_EACH_PTR(stack, tmp) {
 804                 if (!strcmp(tmp->name, name))
 805                         return &tmp->slist;
 806         } END_FOR_EACH_PTR(tmp);
 807         return NULL;
 808 }
 809
 810 void overwrite_slist(struct state_list *from, struct state_list **to)
 811 {
 812         struct sm_state *tmp;
 813
 814         FOR_EACH_PTR(from, tmp) {
 815                 overwrite_sm_state(to, tmp);
 816         } END_FOR_EACH_PTR(tmp);
 817 }