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->implied = 0;
 165         sm_state->my_pool = NULL;
 166         sm_state->left = NULL;
 167         sm_state->right = NULL;
 168         sm_state->nr_children = 1;
 169         sm_state->possible = NULL;
 170         add_ptr_list(&sm_state->possible, sm_state);
 171         return sm_state;
 172 }
 173
 174 static void free_sm_state(struct sm_state *sm)
 175 {
 176         free_slist(&sm->possible);
 177         /*
 178          * fixme.  Free the actual state.
 179          * Right now we leave it until the end of the function
 180          * because we don't want to double free it.
 181          * Use the freelist to not double free things
 182          */
 183 }
 184
 185 static void free_all_sm_states(struct allocation_blob *blob)
 186 {
 187         unsigned int size = sizeof(struct sm_state);
 188         unsigned int offset = 0;
 189
 190         while (offset < blob->offset) {
 191                 free_sm_state((struct sm_state *)(blob->data + offset));
 192                 offset += size;
 193         }
 194 }
 195
 196 /* At the end of every function we free all the sm_states */
 197 void free_every_single_sm_state(void)
 198 {
 199         struct allocator_struct *desc = &sm_state_allocator;
 200         struct allocation_blob *blob = desc->blobs;
 201
 202         desc->blobs = NULL;
 203         desc->allocations = 0;
 204         desc->total_bytes = 0;
 205         desc->useful_bytes = 0;
 206         desc->freelist = NULL;
 207         while (blob) {
 208                 struct allocation_blob *next = blob->next;
 209                 free_all_sm_states(blob);
 210                 blob_free(blob, desc->chunking);
 211                 blob = next;
 212         }
 213         clear_sname_alloc();
 214 }
 215
 216 struct sm_state *clone_state(struct sm_state *s)
 217 {
 218         struct sm_state *ret;
 219
 220         ret = alloc_state_no_name(s->name, s->owner, s->sym, s->state);
 221         ret->merged = s->merged;
 222         ret->implied = s->implied;
 223         /* clone_state() doesn't copy the my_pools.  Each state needs to have
 224            only one my_pool. */
 225         ret->possible = clone_slist(s->possible);
 226         ret->left = s->left;
 227         ret->right = s->right;
 228         ret->nr_children = s->nr_children;
 229         return ret;
 230 }
 231
 232 int is_merged(struct sm_state *sm)
 233 {
 234         return sm->merged;
 235 }
 236
 237 int is_implied(struct sm_state *sm)
 238 {
 239         return sm->implied;
 240 }
 241
 242 int slist_has_state(struct state_list *slist, struct smatch_state *state)
 243 {
 244         struct sm_state *tmp;
 245
 246         FOR_EACH_PTR(slist, tmp) {
 247                 if (tmp->state == state)
 248                         return 1;
 249         } END_FOR_EACH_PTR(tmp);
 250         return 0;
 251 }
 252
 253 static void check_order(struct state_list *slist)
 254 {
 255 #ifdef CHECKORDER
 256         struct sm_state *state;
 257         struct sm_state *last = NULL;
 258         int printed = 0;
 259
 260         FOR_EACH_PTR(slist, state) {
 261                 if (last && cmp_tracker(state, last) <= 0) {
 262                         printf("Error.  Unsorted slist %d vs %d, %p vs %p, "
 263                                "%s vs %s\n", last->owner, state->owner,
 264                                last->sym, state->sym, last->name, state->name);
 265                         printed = 1;
 266                 }
 267                 last = state;
 268         } END_FOR_EACH_PTR(state);
 269
 270         if (printed)
 271                 printf("======\n");
 272 #endif
 273 }
 274
 275 struct state_list *clone_slist(struct state_list *from_slist)
 276 {
 277         struct sm_state *state;
 278         struct state_list *to_slist = NULL;
 279
 280         FOR_EACH_PTR(from_slist, state) {
 281                 add_ptr_list(&to_slist, state);
 282         } END_FOR_EACH_PTR(state);
 283         check_order(to_slist);
 284         return to_slist;
 285 }
 286
 287 struct state_list_stack *clone_stack(struct state_list_stack *from_stack)
 288 {
 289         struct state_list *slist;
 290         struct state_list_stack *to_stack = NULL;
 291
 292         FOR_EACH_PTR(from_stack, slist) {
 293                 push_slist(&to_stack, slist);
 294         } END_FOR_EACH_PTR(slist);
 295         return to_stack;
 296 }
 297
 298 struct smatch_state *merge_states(const char *name, int owner,
 299                                   struct symbol *sym,
 300                                   struct smatch_state *state1,
 301                                   struct smatch_state *state2)
 302 {
 303         struct smatch_state *ret;
 304
 305         if (state1 == state2)
 306                 ret = state1;
 307         else if (__has_merge_function(owner))
 308                 ret = __client_merge_function(owner, name, sym, state1, state2);
 309         else if (!state1 || !state2)
 310                 ret = &undefined;
 311         else
 312                 ret = &merged;
 313         return ret;
 314 }
 315
 316 /*
 317  * add_pool() adds a slist to ->pools. If the slist has already been
 318  * added earlier then it doesn't get added a second time.
 319  */
 320 void add_pool(struct state_list_stack **pools, struct state_list *new)
 321 {
 322         struct state_list *tmp;
 323
 324         FOR_EACH_PTR(*pools, tmp) {
 325                 if (tmp < new)
 326                         continue;
 327                 else if (tmp == new) {
 328                         return;
 329                 } else {
 330                         INSERT_CURRENT(new, tmp);
 331                         return;
 332                 }
 333         } END_FOR_EACH_PTR(tmp);
 334         add_ptr_list(pools, new);
 335 }
 336
 337 struct sm_state *merge_sm_states(struct sm_state *one, struct sm_state *two)
 338 {
 339         struct smatch_state *s;
 340         struct sm_state *result;
 341
 342         if (one == two)
 343                 return one;
 344         s = merge_states(one->name, one->owner, one->sym, one->state, two->state);
 345         result = alloc_state_no_name(one->name, one->owner, one->sym, s);
 346         if (one->line == two->line)
 347                 result->line = one->line;
 348         result->merged = 1;
 349         result->left = one;
 350         result->right = two;
 351         result->nr_children = one->nr_children + two->nr_children;
 352         add_possible(result, one);
 353         add_possible(result, two);
 354
 355         if (debug_states) {
 356                 struct sm_state *tmp;
 357                 int i = 0;
 358
 359                 printf("%d merge name='%s' owner=%d: %s + %s => %s (",
 360                         get_lineno(), one->name, one->owner,
 361                         show_state(one->state), show_state(two->state),
 362                         show_state(s));
 363
 364                 FOR_EACH_PTR(result->possible, tmp) {
 365                         if (i++) {
 366                                 printf(", ");
 367                         }
 368                         printf("%s", show_state(tmp->state));
 369                 } END_FOR_EACH_PTR(tmp);
 370                 printf(")\n");
 371         }
 372
 373         return result;
 374 }
 375
 376 struct sm_state *get_sm_state_slist(struct state_list *slist, const char *name,
 377                                 int owner, struct symbol *sym)
 378 {
 379         struct sm_state *state;
 380
 381         if (!name)
 382                 return NULL;
 383
 384         FOR_EACH_PTR(slist, state) {
 385                 if (state->owner == owner && state->sym == sym
 386                     && !strcmp(state->name, name))
 387                         return state;
 388         } END_FOR_EACH_PTR(state);
 389         return NULL;
 390 }
 391
 392 struct smatch_state *get_state_slist(struct state_list *slist,
 393                                 const char *name, int owner,
 394                                 struct symbol *sym)
 395 {
 396         struct sm_state *state;
 397
 398         state = get_sm_state_slist(slist, name, owner, sym);
 399         if (state)
 400                 return state->state;
 401         return NULL;
 402 }
 403
 404 void overwrite_sm_state(struct state_list **slist, struct sm_state *new)
 405 {
 406         struct sm_state *tmp;
 407
 408         FOR_EACH_PTR(*slist, tmp) {
 409                 if (cmp_tracker(tmp, new) < 0)
 410                         continue;
 411                 else if (cmp_tracker(tmp, new) == 0) {
 412                         REPLACE_CURRENT_PTR(tmp, new);
 413                         return;
 414                 } else {
 415                         INSERT_CURRENT(new, tmp);
 416                         return;
 417                 }
 418         } END_FOR_EACH_PTR(tmp);
 419         add_ptr_list(slist, new);
 420 }
 421
 422 void overwrite_sm_state_stack(struct state_list_stack **stack,
 423                         struct sm_state *state)
 424 {
 425         struct state_list *slist;
 426
 427         slist = pop_slist(stack);
 428         overwrite_sm_state(&slist, state);
 429         push_slist(stack, slist);
 430 }
 431
 432 void set_state_slist(struct state_list **slist, const char *name, int owner,
 433                      struct symbol *sym, struct smatch_state *state)
 434 {
 435         struct sm_state *tmp;
 436         struct sm_state *new = alloc_state(name, owner, sym, state);
 437
 438         FOR_EACH_PTR(*slist, tmp) {
 439                 if (cmp_tracker(tmp, new) < 0)
 440                         continue;
 441                 else if (cmp_tracker(tmp, new) == 0) {
 442                         REPLACE_CURRENT_PTR(tmp, new);
 443                         return;
 444                 } else {
 445                         INSERT_CURRENT(new, tmp);
 446                         return;
 447                 }
 448         } END_FOR_EACH_PTR(tmp);
 449         add_ptr_list(slist, new);
 450 }
 451
 452 void delete_state_slist(struct state_list **slist, const char *name, int owner,
 453                         struct symbol *sym)
 454 {
 455         struct sm_state *state;
 456
 457         FOR_EACH_PTR(*slist, state) {
 458                 if (state->owner == owner && state->sym == sym
 459                     && !strcmp(state->name, name)){
 460                         DELETE_CURRENT_PTR(state);
 461                         return;
 462                 }
 463         } END_FOR_EACH_PTR(state);
 464 }
 465
 466
 467 void push_slist(struct state_list_stack **list_stack, struct state_list *slist)
 468 {
 469         add_ptr_list(list_stack, slist);
 470 }
 471
 472 struct state_list *pop_slist(struct state_list_stack **list_stack)
 473 {
 474         struct state_list *slist;
 475
 476         slist = last_ptr_list((struct ptr_list *)*list_stack);
 477         delete_ptr_list_last((struct ptr_list **)list_stack);
 478         return slist;
 479 }
 480
 481 void free_slist(struct state_list **slist)
 482 {
 483         __free_ptr_list((struct ptr_list **)slist);
 484 }
 485
 486 void free_stack(struct state_list_stack **stack)
 487 {
 488         __free_ptr_list((struct ptr_list **)stack);
 489 }
 490
 491 void free_stack_and_slists(struct state_list_stack **slist_stack)
 492 {
 493         struct state_list *slist;
 494
 495         FOR_EACH_PTR(*slist_stack, slist) {
 496                 free_slist(&slist);
 497         } END_FOR_EACH_PTR(slist);
 498         free_stack(slist_stack);
 499 }
 500
 501 /*
 502  * set_state_stack() sets the state for the top slist on the stack.
 503  */
 504 void set_state_stack(struct state_list_stack **stack, const char *name,
 505                      int owner, struct symbol *sym, struct smatch_state *state)
 506 {
 507         struct state_list *slist;
 508
 509         slist = pop_slist(stack);
 510         set_state_slist(&slist, name, owner, sym, state);
 511         push_slist(stack, slist);
 512 }
 513
 514 /*
 515  * get_sm_state_stack() gets the state for the top slist on the stack.
 516  */
 517 struct sm_state *get_sm_state_stack(struct state_list_stack *stack,
 518                                     const char *name, int owner,
 519                                     struct symbol *sym)
 520 {
 521         struct state_list *slist;
 522         struct sm_state *ret;
 523
 524         slist = pop_slist(&stack);
 525         ret = get_sm_state_slist(slist, name, owner, sym);
 526         push_slist(&stack, slist);
 527         return ret;
 528 }
 529
 530
 531 struct smatch_state *get_state_stack(struct state_list_stack *stack,
 532                                      const char *name, int owner,
 533                                      struct symbol *sym)
 534 {
 535         struct sm_state *state;
 536
 537         state = get_sm_state_stack(stack, name, owner, sym);
 538         if (state)
 539                 return state->state;
 540         return NULL;
 541 }
 542
 543 static void match_states(struct state_list **one, struct state_list **two)
 544 {
 545         struct sm_state *one_state;
 546         struct sm_state *two_state;
 547         struct sm_state *tmp;
 548         struct smatch_state *tmp_state;
 549         struct state_list *add_to_one = NULL;
 550         struct state_list *add_to_two = NULL;
 551
 552         PREPARE_PTR_LIST(*one, one_state);
 553         PREPARE_PTR_LIST(*two, two_state);
 554         for (;;) {
 555                 if (!one_state && !two_state)
 556                         break;
 557                 if (cmp_tracker(one_state, two_state) < 0) {
 558                         tmp_state = __client_unmatched_state_function(one_state);
 559                         tmp = alloc_state_no_name(one_state->name,
 560                                                   one_state->owner,
 561                                                   one_state->sym, tmp_state);
 562                         add_ptr_list(&add_to_two, tmp);
 563                         NEXT_PTR_LIST(one_state);
 564                 } else if (cmp_tracker(one_state, two_state) == 0) {
 565                         NEXT_PTR_LIST(one_state);
 566                         NEXT_PTR_LIST(two_state);
 567                 } else {
 568                         tmp_state = __client_unmatched_state_function(two_state);
 569                         tmp = alloc_state_no_name(two_state->name,
 570                                                   two_state->owner,
 571                                                   two_state->sym, tmp_state);
 572                         add_ptr_list(&add_to_one, tmp);
 573                         NEXT_PTR_LIST(two_state);
 574                 }
 575         }
 576         FINISH_PTR_LIST(two_state);
 577         FINISH_PTR_LIST(one_state);
 578
 579         overwrite_slist(add_to_one, one);
 580         overwrite_slist(add_to_two, two);
 581 }
 582
 583 static void clone_pool_havers(struct state_list *slist)
 584 {
 585         struct sm_state *state;
 586         struct sm_state *new;
 587
 588         FOR_EACH_PTR(slist, state) {
 589                 if (state->my_pool) {
 590                         new = clone_state(state);
 591                         REPLACE_CURRENT_PTR(state, new);
 592                 }
 593         } END_FOR_EACH_PTR(state);
 594 }
 595
 596 /*
 597  * merge_slist() is called whenever paths merge, such as after
 598  * an if statement.  It takes the two slists and creates one.
 599  */
 600 void merge_slist(struct state_list **to, struct state_list *slist)
 601 {
 602         struct sm_state *one_state, *two_state, *tmp;
 603         struct state_list *results = NULL;
 604         struct state_list *implied_one = NULL;
 605         struct state_list *implied_two = NULL;
 606
 607         check_order(*to);
 608         check_order(slist);
 609
 610         /* merging a null and nonnull path gives you only the nonnull path */
 611         if (!slist) {
 612                 return;
 613         }
 614         if (!*to) {
 615                 *to = clone_slist(slist);
 616                 return;
 617         }
 618
 619         implied_one = clone_slist(*to);
 620         implied_two = clone_slist(slist);
 621
 622         match_states(&implied_one, &implied_two);
 623
 624         clone_pool_havers(implied_one);
 625         clone_pool_havers(implied_two);
 626
 627         PREPARE_PTR_LIST(implied_one, one_state);
 628         PREPARE_PTR_LIST(implied_two, two_state);
 629         for (;;) {
 630                 if (!one_state && !two_state)
 631                         break;
 632                 if (cmp_tracker(one_state, two_state) < 0) {
 633                         smatch_msg("error:  Internal smatch error.");
 634                         NEXT_PTR_LIST(one_state);
 635                 } else if (cmp_tracker(one_state, two_state) == 0) {
 636                         if (one_state != two_state) {
 637                                 one_state->my_pool = implied_one;
 638                                 two_state->my_pool = implied_two;
 639                         }
 640
 641                         tmp = merge_sm_states(one_state, two_state);
 642                         add_ptr_list(&results, tmp);
 643                         NEXT_PTR_LIST(one_state);
 644                         NEXT_PTR_LIST(two_state);
 645                 } else {
 646                         smatch_msg("error:  Internal smatch error.");
 647                         NEXT_PTR_LIST(two_state);
 648                 }
 649         }
 650         FINISH_PTR_LIST(two_state);
 651         FINISH_PTR_LIST(one_state);
 652
 653         free_slist(to);
 654         *to = results;
 655 }
 656
 657 /*
 658  * and_slist_stack() is basically the same as popping the top two slists,
 659  * overwriting the one with the other and pushing it back on the stack.
 660  * The difference is that it checks to see that a mutually exclusive
 661  * state isn't included in both stacks.  If smatch sees something like
 662  * "if (a && !a)" it prints a warning.
 663  */
 664 void and_slist_stack(struct state_list_stack **slist_stack)
 665 {
 666         struct sm_state *tmp;
 667         struct state_list *right_slist = pop_slist(slist_stack);
 668
 669         FOR_EACH_PTR(right_slist, tmp) {
 670                 overwrite_sm_state_stack(slist_stack, tmp);
 671         } END_FOR_EACH_PTR(tmp);
 672         free_slist(&right_slist);
 673 }
 674
 675 /*
 676  * or_slist_stack() is for if we have:  if (foo || bar) { foo->baz;
 677  * It pops the two slists from the top of the stack and merges them
 678  * together in a way that preserves the things they have in common
 679  * but creates a merged state for most of the rest.
 680  * You could have code that had:  if (foo || foo) { foo->baz;
 681  * It's this function which ensures smatch does the right thing.
 682  */
 683 void or_slist_stack(struct state_list_stack **pre_conds,
 684                     struct state_list *cur_slist,
 685                     struct state_list_stack **slist_stack)
 686 {
 687         struct state_list *new;
 688         struct state_list *old;
 689         struct state_list *res = NULL;
 690         struct state_list *tmp_slist;
 691
 692         new = pop_slist(slist_stack);
 693         old = pop_slist(slist_stack);
 694
 695         tmp_slist = pop_slist(pre_conds);
 696         res = clone_slist(tmp_slist);
 697         push_slist(pre_conds, tmp_slist);
 698         overwrite_slist(old, &res);
 699
 700         tmp_slist = clone_slist(cur_slist);
 701         overwrite_slist(new, &tmp_slist);
 702
 703         merge_slist(&res, tmp_slist);
 704
 705         push_slist(slist_stack, res);
 706         free_slist(&tmp_slist);
 707         free_slist(&new);
 708         free_slist(&old);
 709 }
 710
 711 /*
 712  * get_slist_from_named_stack() is only used for gotos.
 713  */
 714 struct state_list **get_slist_from_named_stack(struct named_stack *stack,
 715                                               const char *name)
 716 {
 717         struct named_slist *tmp;
 718
 719         FOR_EACH_PTR(stack, tmp) {
 720                 if (!strcmp(tmp->name, name))
 721                         return &tmp->slist;
 722         } END_FOR_EACH_PTR(tmp);
 723         return NULL;
 724 }
 725
 726 void overwrite_slist(struct state_list *from, struct state_list **to)
 727 {
 728         struct sm_state *tmp;
 729
 730         FOR_EACH_PTR(from, tmp) {
 731                 overwrite_sm_state(to, tmp);
 732         } END_FOR_EACH_PTR(tmp);
 733 }