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, 0, 1, "state names", sname);
  21
  22 void __print_slist(struct state_list *slist)
  23 {
  24         struct sm_state *state;
  25         struct sm_state *poss;
  26         int i;
  27
  28         printf("dumping slist at %d\n", get_lineno());
  29         FOR_EACH_PTR(slist, state) {
  30                 printf("%d '%s'=%s (", state->owner, state->name,
  31                         show_state(state->state));
  32                 i = 0;
  33                 FOR_EACH_PTR(state->possible, poss) {
  34                         if (i++)
  35                                 printf(", ");
  36                         printf("%s", show_state(poss->state));
  37                 } END_FOR_EACH_PTR(poss);
  38                 printf(")\n");
  39         } END_FOR_EACH_PTR(state);
  40         printf("---\n");
  41 }
  42
  43
  44 /* NULL states go at the end to simplify merge_slist */
  45 int cmp_tracker(const struct sm_state *a, const struct sm_state *b)
  46 {
  47         int ret;
  48
  49         if (a == b)
  50                 return 0;
  51         if (!b)
  52                 return -1;
  53         if (!a)
  54                 return 1;
  55
  56         if (a->owner > b->owner)
  57                 return -1;
  58         if (a->owner < b->owner)
  59                 return 1;
  60
  61         ret = strcmp(a->name, b->name);
  62         if (ret)
  63                 return ret;
  64
  65         if (!b->sym && a->sym)
  66                 return -1;
  67         if (!a->sym && b->sym)
  68                 return 1;
  69         if (a->sym > b->sym)
  70                 return -1;
  71         if (a->sym < b->sym)
  72                 return 1;
  73
  74         return 0;
  75 }
  76
  77 static int cmp_sm_states(const struct sm_state *a, const struct sm_state *b)
  78 {
  79         int ret;
  80
  81         ret = cmp_tracker(a, b);
  82         if (ret)
  83                 return ret;
  84
  85         /* todo:  add hook for smatch_extra.c */
  86         if (a->state > b->state)
  87                 return -1;
  88         if (a->state < b->state)
  89                 return 1;
  90         return 0;
  91 }
  92
  93 static struct sm_state *alloc_state_no_name(const char *name, int owner,
  94                                      struct symbol *sym,
  95                                      struct smatch_state *state)
  96 {
  97         struct sm_state *tmp;
  98
  99         tmp = alloc_state(NULL, owner, sym, state);
 100         tmp->name = name;
 101         return tmp;
 102 }
 103
 104 void add_sm_state_slist(struct state_list **slist, struct sm_state *new)
 105 {
 106         struct sm_state *tmp;
 107
 108         FOR_EACH_PTR(*slist, tmp) {
 109                 if (cmp_sm_states(tmp, new) < 0)
 110                         continue;
 111                 else if (cmp_sm_states(tmp, new) == 0) {
 112                         return;
 113                 } else {
 114                         INSERT_CURRENT(new, tmp);
 115                         return;
 116                 }
 117         } END_FOR_EACH_PTR(tmp);
 118         add_ptr_list(slist, new);
 119 }
 120
 121 static void add_possible(struct sm_state *sm, struct sm_state *new)
 122 {
 123         struct sm_state *tmp;
 124         struct sm_state *tmp2;
 125
 126         if (!new) {
 127                 struct smatch_state *s;
 128
 129                 s = merge_states(sm->name, sm->owner, sm->sym, sm->state, NULL);
 130                 tmp = alloc_state_no_name(sm->name, sm->owner, sm->sym, s);
 131                 add_sm_state_slist(&sm->possible, tmp);
 132                 return;
 133         }
 134
 135         FOR_EACH_PTR(new->possible, tmp) {
 136                 tmp2 = alloc_state_no_name(tmp->name, tmp->owner, tmp->sym,
 137                                            tmp->state);
 138                 add_sm_state_slist(&sm->possible, tmp2);
 139         } END_FOR_EACH_PTR(tmp);
 140 }
 141
 142 char *alloc_sname(const char *str)
 143 {
 144         char *tmp;
 145
 146         if (!str)
 147                 return NULL;
 148         tmp = __alloc_sname(strlen(str) + 1);
 149         strcpy(tmp, str);
 150         return tmp;
 151 }
 152
 153 struct sm_state *alloc_state(const char *name, int owner,
 154                              struct symbol *sym, struct smatch_state *state)
 155 {
 156         struct sm_state *sm_state = __alloc_sm_state(0);
 157
 158         sm_state->name = alloc_sname(name);
 159         sm_state->owner = owner;
 160         sm_state->sym = sym;
 161         sm_state->state = state;
 162         sm_state->line = get_lineno();
 163         sm_state->merged = 0;
 164         sm_state->my_pools = NULL;
 165         sm_state->pre_left = NULL;
 166         sm_state->pre_right = NULL;
 167         sm_state->possible = NULL;
 168         add_ptr_list(&sm_state->possible, sm_state);
 169         return sm_state;
 170 }
 171
 172 static void free_sm_state(struct sm_state *sm)
 173 {
 174         free_slist(&sm->possible);
 175         free_stack(&sm->my_pools);
 176         /*
 177          * fixme.  Free the actual state.
 178          * Right now we leave it until the end of the function
 179          * because we don't want to double free it.
 180          * Use the freelist to not double free things
 181          */
 182 }
 183
 184 static void free_all_sm_states(struct allocation_blob *blob)
 185 {
 186         unsigned int size = sizeof(struct sm_state);
 187         unsigned int offset = 0;
 188
 189         while (offset < blob->offset) {
 190                 free_sm_state((struct sm_state *)(blob->data + offset));
 191                 offset += size;
 192         }
 193 }
 194
 195 /* At the end of every function we free all the sm_states */
 196 void free_every_single_sm_state(void)
 197 {
 198         struct allocator_struct *desc = &sm_state_allocator;
 199         struct allocation_blob *blob = desc->blobs;
 200
 201         desc->blobs = NULL;
 202         desc->allocations = 0;
 203         desc->total_bytes = 0;
 204         desc->useful_bytes = 0;
 205         desc->freelist = NULL;
 206         while (blob) {
 207                 struct allocation_blob *next = blob->next;
 208                 free_all_sm_states(blob);
 209                 blob_free(blob, desc->chunking);
 210                 blob = next;
 211         }
 212         clear_sname_alloc();
 213 }
 214
 215 struct sm_state *clone_state(struct sm_state *s)
 216 {
 217         struct sm_state *ret;
 218
 219         ret = alloc_state_no_name(s->name, s->owner, s->sym, s->state);
 220         ret->line = s->line;
 221         ret->merged = s->merged;
 222         ret->my_pools = clone_stack(s->my_pools);
 223         ret->possible = clone_slist(s->possible);
 224         ret->pre_left = s->pre_left;
 225         ret->pre_right = s->pre_right;
 226         return ret;
 227 }
 228
 229 int is_merged(struct sm_state *sm)
 230 {
 231         return sm->merged;
 232 }
 233
 234 int slist_has_state(struct state_list *slist, struct smatch_state *state)
 235 {
 236         struct sm_state *tmp;
 237
 238         FOR_EACH_PTR(slist, tmp) {
 239                 if (tmp->state == state)
 240                         return 1;
 241         } END_FOR_EACH_PTR(tmp);
 242         return 0;
 243 }
 244
 245 static void check_order(struct state_list *slist)
 246 {
 247 #ifdef CHECKORDER
 248         struct sm_state *state;
 249         struct sm_state *last = NULL;
 250         int printed = 0;
 251
 252         FOR_EACH_PTR(slist, state) {
 253                 if (last && cmp_tracker(state, last) <= 0) {
 254                         printf("Error.  Unsorted slist %d vs %d, %p vs %p, "
 255                                "%s vs %s\n", last->owner, state->owner,
 256                                last->sym, state->sym, last->name, state->name);
 257                         printed = 1;
 258                 }
 259                 last = state;
 260         } END_FOR_EACH_PTR(state);
 261
 262         if (printed)
 263                 printf("======\n");
 264 #endif
 265 }
 266
 267 struct state_list *clone_slist(struct state_list *from_slist)
 268 {
 269         struct sm_state *state;
 270         struct state_list *to_slist = NULL;
 271
 272         FOR_EACH_PTR(from_slist, state) {
 273                 add_ptr_list(&to_slist, state);
 274         } END_FOR_EACH_PTR(state);
 275         check_order(to_slist);
 276         return to_slist;
 277 }
 278
 279 struct state_list *clone_slist_and_states(struct state_list *from_slist)
 280 {
 281         struct sm_state *state;
 282         struct sm_state *tmp;
 283         struct state_list *to_slist = NULL;
 284
 285         FOR_EACH_PTR(from_slist, state) {
 286                 tmp = clone_state(state);
 287                 add_ptr_list(&to_slist, tmp);
 288         } END_FOR_EACH_PTR(state);
 289         check_order(to_slist);
 290         return to_slist;
 291 }
 292
 293 struct state_list_stack *clone_stack(struct state_list_stack *from_stack)
 294 {
 295         struct state_list *slist;
 296         struct state_list_stack *to_stack = NULL;
 297
 298         FOR_EACH_PTR(from_stack, slist) {
 299                 push_slist(&to_stack, slist);
 300         } END_FOR_EACH_PTR(slist);
 301         return to_stack;
 302 }
 303
 304 struct smatch_state *merge_states(const char *name, int owner,
 305                                   struct symbol *sym,
 306                                   struct smatch_state *state1,
 307                                   struct smatch_state *state2)
 308 {
 309         struct smatch_state *ret;
 310
 311         if (state1 == state2)
 312                 ret = state1;
 313         else if (__has_merge_function(owner))
 314                 ret = __client_merge_function(owner, name, sym, state1, state2);
 315         else if (!state1 || !state2)
 316                 ret = &undefined;
 317         else
 318                 ret = &merged;
 319         return ret;
 320 }
 321
 322 /*
 323  * add_pool() adds a slist to ->pools. If the slist has already been
 324  * added earlier then it doesn't get added a second time.
 325  */
 326 void add_pool(struct state_list_stack **pools, struct state_list *new)
 327 {
 328         struct state_list *tmp;
 329
 330         FOR_EACH_PTR(*pools, tmp) {
 331                 if (tmp < new)
 332                         continue;
 333                 else if (tmp == new) {
 334                         return;
 335                 } else {
 336                         INSERT_CURRENT(new, tmp);
 337                         return;
 338                 }
 339         } END_FOR_EACH_PTR(tmp);
 340         add_ptr_list(pools, new);
 341 }
 342
 343 void merge_pools(struct state_list_stack **to, struct state_list_stack *from)
 344 {
 345         struct state_list *tmp;
 346
 347         FOR_EACH_PTR(from, tmp) {
 348                 add_pool(to, tmp);
 349         } END_FOR_EACH_PTR(tmp);
 350 }
 351
 352 struct sm_state *merge_sm_states(struct sm_state *one, struct sm_state *two)
 353 {
 354         struct smatch_state *s;
 355         struct sm_state *result;
 356
 357         if (one == two)
 358                 return one;
 359         s = merge_states(one->name, one->owner, one->sym, one->state,
 360                         (two?two->state:NULL));
 361         result = alloc_state_no_name(one->name, one->owner, one->sym, s);
 362         if (two && one->line == two->line)
 363                 result->line = one->line;
 364         result->merged = 1;
 365         result->pre_left = one;
 366         result->pre_right = two;
 367         add_possible(result, one);
 368         add_possible(result, two);
 369
 370         if (debug_states) {
 371                 struct sm_state *tmp;
 372                 int i = 0;
 373
 374                 printf("%d merge name='%s' owner=%d: %s + %s => %s (",
 375                         get_lineno(), one->name, one->owner,
 376                         show_state(one->state), show_state(two?two->state:NULL),
 377                         show_state(s));
 378
 379                 FOR_EACH_PTR(result->possible, tmp) {
 380                         if (i++) {
 381                                 printf(", ");
 382                         }
 383                         printf("%s", show_state(tmp->state));
 384                 } END_FOR_EACH_PTR(tmp);
 385                 printf(")\n");
 386         }
 387
 388         return result;
 389 }
 390
 391 struct sm_state *get_sm_state_slist(struct state_list *slist, const char *name,
 392                                 int owner, struct symbol *sym)
 393 {
 394         struct sm_state *state;
 395
 396         if (!name)
 397                 return NULL;
 398
 399         FOR_EACH_PTR(slist, state) {
 400                 if (state->owner == owner && state->sym == sym
 401                     && !strcmp(state->name, name))
 402                         return state;
 403         } END_FOR_EACH_PTR(state);
 404         return NULL;
 405 }
 406
 407 struct smatch_state *get_state_slist(struct state_list *slist,
 408                                 const char *name, int owner,
 409                                 struct symbol *sym)
 410 {
 411         struct sm_state *state;
 412
 413         state = get_sm_state_slist(slist, name, owner, sym);
 414         if (state)
 415                 return state->state;
 416         return NULL;
 417 }
 418
 419 void overwrite_sm_state(struct state_list **slist, struct sm_state *new)
 420 {
 421         struct sm_state *tmp;
 422
 423         FOR_EACH_PTR(*slist, tmp) {
 424                 if (cmp_tracker(tmp, new) < 0)
 425                         continue;
 426                 else if (cmp_tracker(tmp, new) == 0) {
 427                         REPLACE_CURRENT_PTR(tmp, new);
 428                         return;
 429                 } else {
 430                         INSERT_CURRENT(new, tmp);
 431                         return;
 432                 }
 433         } END_FOR_EACH_PTR(tmp);
 434         add_ptr_list(slist, new);
 435 }
 436
 437 void overwrite_sm_state_stack(struct state_list_stack **stack,
 438                         struct sm_state *state)
 439 {
 440         struct state_list *slist;
 441
 442         slist = pop_slist(stack);
 443         overwrite_sm_state(&slist, state);
 444         push_slist(stack, slist);
 445 }
 446
 447 void set_state_slist(struct state_list **slist, const char *name, int owner,
 448                      struct symbol *sym, struct smatch_state *state)
 449 {
 450         struct sm_state *tmp;
 451         struct sm_state *new = alloc_state(name, owner, sym, state);
 452
 453         FOR_EACH_PTR(*slist, tmp) {
 454                 if (cmp_tracker(tmp, new) < 0)
 455                         continue;
 456                 else if (cmp_tracker(tmp, new) == 0) {
 457                         REPLACE_CURRENT_PTR(tmp, new);
 458                         return;
 459                 } else {
 460                         INSERT_CURRENT(new, tmp);
 461                         return;
 462                 }
 463         } END_FOR_EACH_PTR(tmp);
 464         add_ptr_list(slist, new);
 465 }
 466
 467 void delete_state_slist(struct state_list **slist, const char *name, int owner,
 468                         struct symbol *sym)
 469 {
 470         struct sm_state *state;
 471
 472         FOR_EACH_PTR(*slist, state) {
 473                 if (state->owner == owner && state->sym == sym
 474                     && !strcmp(state->name, name)){
 475                         DELETE_CURRENT_PTR(state);
 476                         return;
 477                 }
 478         } END_FOR_EACH_PTR(state);
 479 }
 480
 481
 482 void push_slist(struct state_list_stack **list_stack, struct state_list *slist)
 483 {
 484         add_ptr_list(list_stack, slist);
 485 }
 486
 487 struct state_list *pop_slist(struct state_list_stack **list_stack)
 488 {
 489         struct state_list *slist;
 490
 491         slist = last_ptr_list((struct ptr_list *)*list_stack);
 492         delete_ptr_list_last((struct ptr_list **)list_stack);
 493         return slist;
 494 }
 495
 496 void free_slist(struct state_list **slist)
 497 {
 498         __free_ptr_list((struct ptr_list **)slist);
 499 }
 500
 501 void free_stack(struct state_list_stack **stack)
 502 {
 503         __free_ptr_list((struct ptr_list **)stack);
 504 }
 505
 506 void free_stack_and_slists(struct state_list_stack **slist_stack)
 507 {
 508         struct state_list *slist;
 509
 510         FOR_EACH_PTR(*slist_stack, slist) {
 511                 free_slist(&slist);
 512         } END_FOR_EACH_PTR(slist);
 513         free_stack(slist_stack);
 514 }
 515
 516 /*
 517  * set_state_stack() sets the state for the top slist on the stack.
 518  */
 519 void set_state_stack(struct state_list_stack **stack, const char *name,
 520                      int owner, struct symbol *sym, struct smatch_state *state)
 521 {
 522         struct state_list *slist;
 523
 524         slist = pop_slist(stack);
 525         set_state_slist(&slist, name, owner, sym, state);
 526         push_slist(stack, slist);
 527 }
 528
 529 /*
 530  * get_sm_state_stack() gets the state for the top slist on the stack.
 531  */
 532 struct sm_state *get_sm_state_stack(struct state_list_stack *stack,
 533                                     const char *name, int owner,
 534                                     struct symbol *sym)
 535 {
 536         struct state_list *slist;
 537         struct sm_state *ret;
 538
 539         slist = pop_slist(&stack);
 540         ret = get_sm_state_slist(slist, name, owner, sym);
 541         push_slist(&stack, slist);
 542         return ret;
 543 }
 544
 545
 546 struct smatch_state *get_state_stack(struct state_list_stack *stack,
 547                                      const char *name, int owner,
 548                                      struct symbol *sym)
 549 {
 550         struct sm_state *state;
 551
 552         state = get_sm_state_stack(stack, name, owner, sym);
 553         if (state)
 554                 return state->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_state;
 561         struct sm_state *two_state;
 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_state);
 568         PREPARE_PTR_LIST(*two, two_state);
 569         for (;;) {
 570                 if (!one_state && !two_state)
 571                         break;
 572                 if (cmp_tracker(one_state, two_state) < 0) {
 573                         tmp_state = __client_unmatched_state_function(one_state);
 574                         tmp = alloc_state_no_name(one_state->name,
 575                                                   one_state->owner,
 576                                                   one_state->sym, tmp_state);
 577                         add_ptr_list(&add_to_two, tmp);
 578                         NEXT_PTR_LIST(one_state);
 579                 } else if (cmp_tracker(one_state, two_state) == 0) {
 580                         NEXT_PTR_LIST(one_state);
 581                         NEXT_PTR_LIST(two_state);
 582                 } else {
 583                         tmp_state = __client_unmatched_state_function(two_state);
 584                         tmp = alloc_state_no_name(two_state->name,
 585                                                   two_state->owner,
 586                                                   two_state->sym, tmp_state);
 587                         add_ptr_list(&add_to_one, tmp);
 588                         NEXT_PTR_LIST(two_state);
 589                 }
 590         }
 591         FINISH_PTR_LIST(two_state);
 592         FINISH_PTR_LIST(one_state);
 593
 594         overwrite_slist(add_to_one, one);
 595         overwrite_slist(add_to_two, two);
 596 }
 597
 598 static void clone_modified(struct state_list **one, struct state_list **two)
 599 {
 600         struct sm_state *one_state;
 601         struct sm_state *two_state;
 602         struct sm_state *clone;
 603         struct state_list *add_to_one = NULL;
 604         struct state_list *add_to_two = NULL;
 605
 606         PREPARE_PTR_LIST(*one, one_state);
 607         PREPARE_PTR_LIST(*two, two_state);
 608         for (;;) {
 609                 if (!one_state && !two_state)
 610                         break;
 611                 if (cmp_tracker(one_state, two_state) < 0) {
 612                         NEXT_PTR_LIST(one_state);
 613                 } else if (cmp_tracker(one_state, two_state) == 0) {
 614                         if (one_state != two_state) {
 615                                 clone = clone_state(one_state);
 616                                 add_ptr_list(&add_to_one, clone);
 617                                 clone = clone_state(two_state);
 618                                 add_ptr_list(&add_to_two, clone);
 619                         }
 620                         NEXT_PTR_LIST(one_state);
 621                         NEXT_PTR_LIST(two_state);
 622                 } else {
 623                         NEXT_PTR_LIST(two_state);
 624                 }
 625         }
 626         FINISH_PTR_LIST(two_state);
 627         FINISH_PTR_LIST(one_state);
 628
 629         overwrite_slist(add_to_one, one);
 630         overwrite_slist(add_to_two, two);
 631 }
 632
 633 /*
 634  * merge_slist() is called whenever paths merge, such as after
 635  * an if statement.  It takes the two slists and creates one.
 636  */
 637 static void __merge_slist(struct state_list **to, struct state_list *slist, int clone)
 638 {
 639         struct sm_state *to_state, *state, *tmp;
 640         struct state_list *results = NULL;
 641         struct state_list *implied_to = NULL;
 642         struct state_list *implied_from = NULL;
 643
 644         check_order(*to);
 645         check_order(slist);
 646
 647         /* merging a null and nonnull path gives you only the nonnull path */
 648         if (!slist) {
 649                 return;
 650         }
 651         if (!*to) {
 652                 *to = clone_slist(slist);
 653                 return;
 654         }
 655
 656         implied_to = clone_slist(*to);
 657         implied_from = clone_slist(slist);
 658
 659         match_states(&implied_to, &implied_from);
 660         if (clone)
 661                 clone_modified(&implied_to, &implied_from);
 662
 663         PREPARE_PTR_LIST(implied_to, to_state);
 664         PREPARE_PTR_LIST(implied_from, state);
 665         for (;;) {
 666                 if (!to_state && !state)
 667                         break;
 668                 if (cmp_tracker(to_state, state) < 0) {
 669                         smatch_msg("error:  Internal smatch error.");
 670                         NEXT_PTR_LIST(to_state);
 671                 } else if (cmp_tracker(to_state, state) == 0) {
 672                         if (to_state != state) {
 673                                 add_pool(&to_state->my_pools, implied_to);
 674                                 add_pool(&state->my_pools, implied_from);
 675                         }
 676
 677                         tmp = merge_sm_states(to_state, state);
 678                         add_ptr_list(&results, tmp);
 679                         NEXT_PTR_LIST(to_state);
 680                         NEXT_PTR_LIST(state);
 681                 } else {
 682                         smatch_msg("error:  Internal smatch error.");
 683                         NEXT_PTR_LIST(state);
 684                 }
 685         }
 686         FINISH_PTR_LIST(state);
 687         FINISH_PTR_LIST(to_state);
 688
 689         free_slist(to);
 690         *to = results;
 691 }
 692
 693 void merge_slist(struct state_list **to, struct state_list *slist)
 694 {
 695         __merge_slist(to, slist, 0);
 696 }
 697
 698 void merge_slist_clone(struct state_list **to, struct state_list *slist)
 699 {
 700         __merge_slist(to, slist, 1);
 701 }
 702
 703 /*
 704  * and_slist_stack() is basically the same as popping the top two slists,
 705  * overwriting the one with the other and pushing it back on the stack.
 706  * The difference is that it checks to see that a mutually exclusive
 707  * state isn't included in both stacks.  If smatch sees something like
 708  * "if (a && !a)" it prints a warning.
 709  */
 710 void and_slist_stack(struct state_list_stack **slist_stack)
 711 {
 712         struct sm_state *tmp;
 713         struct state_list *right_slist = pop_slist(slist_stack);
 714
 715         FOR_EACH_PTR(right_slist, tmp) {
 716                 overwrite_sm_state_stack(slist_stack, tmp);
 717         } END_FOR_EACH_PTR(tmp);
 718         free_slist(&right_slist);
 719 }
 720
 721 /*
 722  * or_slist_stack() is for if we have:  if (foo || bar) { foo->baz;
 723  * It pops the two slists from the top of the stack and merges them
 724  * together in a way that preserves the things they have in common
 725  * but creates a merged state for most of the rest.
 726  * You could have code that had:  if (foo || foo) { foo->baz;
 727  * It's this function which ensures smatch does the right thing.
 728  */
 729 void or_slist_stack(struct state_list_stack **pre_conds,
 730                     struct state_list *cur_slist,
 731                     struct state_list_stack **slist_stack)
 732 {
 733         struct state_list *new;
 734         struct state_list *old;
 735         struct state_list *res = NULL;
 736         struct state_list *tmp_slist;
 737
 738         new = pop_slist(slist_stack);
 739         old = pop_slist(slist_stack);
 740
 741         tmp_slist = pop_slist(pre_conds);
 742         res = clone_slist(tmp_slist);
 743         push_slist(pre_conds, tmp_slist);
 744         overwrite_slist(old, &res);
 745
 746         tmp_slist = clone_slist(cur_slist);
 747         overwrite_slist(new, &tmp_slist);
 748
 749         merge_slist(&res, tmp_slist);
 750
 751         push_slist(slist_stack, res);
 752         free_slist(&tmp_slist);
 753         free_slist(&new);
 754         free_slist(&old);
 755 }
 756
 757 /*
 758  * get_slist_from_named_stack() is only used for gotos.
 759  */
 760 struct state_list **get_slist_from_named_stack(struct named_stack *stack,
 761                                               const char *name)
 762 {
 763         struct named_slist *tmp;
 764
 765         FOR_EACH_PTR(stack, tmp) {
 766                 if (!strcmp(tmp->name, name))
 767                         return &tmp->slist;
 768         } END_FOR_EACH_PTR(tmp);
 769         return NULL;
 770 }
 771
 772 void overwrite_slist(struct state_list *from, struct state_list **to)
 773 {
 774         struct sm_state *tmp;
 775
 776         FOR_EACH_PTR(from, tmp) {
 777                 overwrite_sm_state(to, tmp);
 778         } END_FOR_EACH_PTR(tmp);
 779 }