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("[%s] '%s'=%s (", check_name(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(int owner, const char *name,
  94                                      struct symbol *sym,
  95                                      struct smatch_state *state)
  96 {
  97         struct sm_state *tmp;
  98
  99         tmp = alloc_state(owner, NULL, 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->owner, sm->name, sm->sym, sm->state, NULL);
 130                 tmp = alloc_state_no_name(sm->owner, sm->name, 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->owner,tmp->name, 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(int owner, const char *name,
 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->owner, s->name, 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(int owner, const char *name,
 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->owner, one->name, one->sym, one->state, two->state);
 345         result = alloc_state_no_name(one->owner, one->name, 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' [%s] %s(L %d) + %s(L %d) => %s (",
 360                         get_lineno(), one->name, check_name(one->owner),
 361                         show_state(one->state), one->line,
 362                         show_state(two->state), two->line,
 363                         show_state(s));
 364
 365                 FOR_EACH_PTR(result->possible, tmp) {
 366                         if (i++) {
 367                                 printf(", ");
 368                         }
 369                         printf("%s", show_state(tmp->state));
 370                 } END_FOR_EACH_PTR(tmp);
 371                 printf(")\n");
 372         }
 373
 374         return result;
 375 }
 376
 377 struct sm_state *get_sm_state_slist(struct state_list *slist, int owner, const char *name,
 378                                 struct symbol *sym)
 379 {
 380         struct sm_state *state;
 381
 382         if (!name)
 383                 return NULL;
 384
 385         FOR_EACH_PTR(slist, state) {
 386                 if (state->owner == owner && state->sym == sym
 387                     && !strcmp(state->name, name))
 388                         return state;
 389         } END_FOR_EACH_PTR(state);
 390         return NULL;
 391 }
 392
 393 struct smatch_state *get_state_slist(struct state_list *slist,
 394                                 int owner, const char *name,
 395                                 struct symbol *sym)
 396 {
 397         struct sm_state *state;
 398
 399         state = get_sm_state_slist(slist, owner, name, sym);
 400         if (state)
 401                 return state->state;
 402         return NULL;
 403 }
 404
 405 void overwrite_sm_state(struct state_list **slist, struct sm_state *new)
 406 {
 407         struct sm_state *tmp;
 408
 409         FOR_EACH_PTR(*slist, tmp) {
 410                 if (cmp_tracker(tmp, new) < 0)
 411                         continue;
 412                 else if (cmp_tracker(tmp, new) == 0) {
 413                         REPLACE_CURRENT_PTR(tmp, new);
 414                         return;
 415                 } else {
 416                         INSERT_CURRENT(new, tmp);
 417                         return;
 418                 }
 419         } END_FOR_EACH_PTR(tmp);
 420         add_ptr_list(slist, new);
 421 }
 422
 423 void overwrite_sm_state_stack(struct state_list_stack **stack,
 424                         struct sm_state *state)
 425 {
 426         struct state_list *slist;
 427
 428         slist = pop_slist(stack);
 429         overwrite_sm_state(&slist, state);
 430         push_slist(stack, slist);
 431 }
 432
 433 void set_state_slist(struct state_list **slist, int owner, const char *name,
 434                      struct symbol *sym, struct smatch_state *state)
 435 {
 436         struct sm_state *tmp;
 437         struct sm_state *new = alloc_state(owner, name, sym, state);
 438
 439         FOR_EACH_PTR(*slist, tmp) {
 440                 if (cmp_tracker(tmp, new) < 0)
 441                         continue;
 442                 else if (cmp_tracker(tmp, new) == 0) {
 443                         REPLACE_CURRENT_PTR(tmp, new);
 444                         return;
 445                 } else {
 446                         INSERT_CURRENT(new, tmp);
 447                         return;
 448                 }
 449         } END_FOR_EACH_PTR(tmp);
 450         add_ptr_list(slist, new);
 451 }
 452
 453 void delete_state_slist(struct state_list **slist, int owner, const char *name,
 454                         struct symbol *sym)
 455 {
 456         struct sm_state *state;
 457
 458         FOR_EACH_PTR(*slist, state) {
 459                 if (state->owner == owner && state->sym == sym
 460                     && !strcmp(state->name, name)){
 461                         DELETE_CURRENT_PTR(state);
 462                         return;
 463                 }
 464         } END_FOR_EACH_PTR(state);
 465 }
 466
 467
 468 void push_slist(struct state_list_stack **list_stack, struct state_list *slist)
 469 {
 470         add_ptr_list(list_stack, slist);
 471 }
 472
 473 struct state_list *pop_slist(struct state_list_stack **list_stack)
 474 {
 475         struct state_list *slist;
 476
 477         slist = last_ptr_list((struct ptr_list *)*list_stack);
 478         delete_ptr_list_last((struct ptr_list **)list_stack);
 479         return slist;
 480 }
 481
 482 void free_slist(struct state_list **slist)
 483 {
 484         __free_ptr_list((struct ptr_list **)slist);
 485 }
 486
 487 void free_stack(struct state_list_stack **stack)
 488 {
 489         __free_ptr_list((struct ptr_list **)stack);
 490 }
 491
 492 void free_stack_and_slists(struct state_list_stack **slist_stack)
 493 {
 494         struct state_list *slist;
 495
 496         FOR_EACH_PTR(*slist_stack, slist) {
 497                 free_slist(&slist);
 498         } END_FOR_EACH_PTR(slist);
 499         free_stack(slist_stack);
 500 }
 501
 502 /*
 503  * set_state_stack() sets the state for the top slist on the stack.
 504  */
 505 void set_state_stack(struct state_list_stack **stack, int owner, const char *name,
 506                 struct symbol *sym, struct smatch_state *state)
 507 {
 508         struct state_list *slist;
 509
 510         slist = pop_slist(stack);
 511         set_state_slist(&slist, owner, name, sym, state);
 512         push_slist(stack, slist);
 513 }
 514
 515 /*
 516  * get_sm_state_stack() gets the state for the top slist on the stack.
 517  */
 518 struct sm_state *get_sm_state_stack(struct state_list_stack *stack,
 519                                 int owner, const char *name,
 520                                 struct symbol *sym)
 521 {
 522         struct state_list *slist;
 523         struct sm_state *ret;
 524
 525         slist = pop_slist(&stack);
 526         ret = get_sm_state_slist(slist, owner, name, sym);
 527         push_slist(&stack, slist);
 528         return ret;
 529 }
 530
 531
 532 struct smatch_state *get_state_stack(struct state_list_stack *stack,
 533                                 int owner, const char *name,
 534                                 struct symbol *sym)
 535 {
 536         struct sm_state *state;
 537
 538         state = get_sm_state_stack(stack, owner, name, sym);
 539         if (state)
 540                 return state->state;
 541         return NULL;
 542 }
 543
 544 static void match_states(struct state_list **one, struct state_list **two)
 545 {
 546         struct sm_state *one_state;
 547         struct sm_state *two_state;
 548         struct sm_state *tmp;
 549         struct smatch_state *tmp_state;
 550         struct state_list *add_to_one = NULL;
 551         struct state_list *add_to_two = NULL;
 552
 553         PREPARE_PTR_LIST(*one, one_state);
 554         PREPARE_PTR_LIST(*two, two_state);
 555         for (;;) {
 556                 if (!one_state && !two_state)
 557                         break;
 558                 if (cmp_tracker(one_state, two_state) < 0) {
 559                         tmp_state = __client_unmatched_state_function(one_state);
 560                         tmp = alloc_state_no_name(one_state->owner,one_state->name,
 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->owner,two_state->name,
 570                                                   two_state->sym, tmp_state);
 571                         add_ptr_list(&add_to_one, tmp);
 572                         NEXT_PTR_LIST(two_state);
 573                 }
 574         }
 575         FINISH_PTR_LIST(two_state);
 576         FINISH_PTR_LIST(one_state);
 577
 578         overwrite_slist(add_to_one, one);
 579         overwrite_slist(add_to_two, two);
 580 }
 581
 582 static void clone_pool_havers(struct state_list *slist)
 583 {
 584         struct sm_state *state;
 585         struct sm_state *new;
 586
 587         FOR_EACH_PTR(slist, state) {
 588                 if (state->my_pool) {
 589                         new = clone_state(state);
 590                         REPLACE_CURRENT_PTR(state, new);
 591                 }
 592         } END_FOR_EACH_PTR(state);
 593 }
 594
 595 /*
 596  * merge_slist() is called whenever paths merge, such as after
 597  * an if statement.  It takes the two slists and creates one.
 598  */
 599 void merge_slist(struct state_list **to, struct state_list *slist)
 600 {
 601         struct sm_state *one_state, *two_state, *tmp;
 602         struct state_list *results = NULL;
 603         struct state_list *implied_one = NULL;
 604         struct state_list *implied_two = NULL;
 605
 606         check_order(*to);
 607         check_order(slist);
 608
 609         /* merging a null and nonnull path gives you only the nonnull path */
 610         if (!slist) {
 611                 return;
 612         }
 613         if (!*to) {
 614                 *to = clone_slist(slist);
 615                 return;
 616         }
 617
 618         implied_one = clone_slist(*to);
 619         implied_two = clone_slist(slist);
 620
 621         match_states(&implied_one, &implied_two);
 622
 623         clone_pool_havers(implied_one);
 624         clone_pool_havers(implied_two);
 625
 626         PREPARE_PTR_LIST(implied_one, one_state);
 627         PREPARE_PTR_LIST(implied_two, two_state);
 628         for (;;) {
 629                 if (!one_state && !two_state)
 630                         break;
 631                 if (cmp_tracker(one_state, two_state) < 0) {
 632                         sm_msg("error:  Internal smatch error.");
 633                         NEXT_PTR_LIST(one_state);
 634                 } else if (cmp_tracker(one_state, two_state) == 0) {
 635                         if (one_state != two_state) {
 636                                 one_state->my_pool = implied_one;
 637                                 two_state->my_pool = implied_two;
 638                         }
 639
 640                         tmp = merge_sm_states(one_state, two_state);
 641                         add_ptr_list(&results, tmp);
 642                         NEXT_PTR_LIST(one_state);
 643                         NEXT_PTR_LIST(two_state);
 644                 } else {
 645                         sm_msg("error:  Internal smatch error.");
 646                         NEXT_PTR_LIST(two_state);
 647                 }
 648         }
 649         FINISH_PTR_LIST(two_state);
 650         FINISH_PTR_LIST(one_state);
 651
 652         free_slist(to);
 653         *to = results;
 654 }
 655
 656 /*
 657  * and_slist_stack() is basically the same as popping the top two slists,
 658  * overwriting the one with the other and pushing it back on the stack.
 659  * The difference is that it checks to see that a mutually exclusive
 660  * state isn't included in both stacks.  If smatch sees something like
 661  * "if (a && !a)" it assumes the second one is true.
 662  */
 663 void and_slist_stack(struct state_list_stack **slist_stack)
 664 {
 665         struct sm_state *tmp;
 666         struct state_list *right_slist = pop_slist(slist_stack);
 667
 668         FOR_EACH_PTR(right_slist, tmp) {
 669                 overwrite_sm_state_stack(slist_stack, tmp);
 670         } END_FOR_EACH_PTR(tmp);
 671         free_slist(&right_slist);
 672 }
 673
 674 /*
 675  * or_slist_stack() is for if we have:  if (foo || bar) { foo->baz;
 676  * It pops the two slists from the top of the stack and merges them
 677  * together in a way that preserves the things they have in common
 678  * but creates a merged state for most of the rest.
 679  * You could have code that had:  if (foo || foo) { foo->baz;
 680  * It's this function which ensures smatch does the right thing.
 681  */
 682 void or_slist_stack(struct state_list_stack **pre_conds,
 683                     struct state_list *cur_slist,
 684                     struct state_list_stack **slist_stack)
 685 {
 686         struct state_list *new;
 687         struct state_list *old;
 688         struct state_list *res = NULL;
 689         struct state_list *tmp_slist;
 690
 691         new = pop_slist(slist_stack);
 692         old = pop_slist(slist_stack);
 693
 694         tmp_slist = pop_slist(pre_conds);
 695         res = clone_slist(tmp_slist);
 696         push_slist(pre_conds, tmp_slist);
 697         overwrite_slist(old, &res);
 698
 699         tmp_slist = clone_slist(cur_slist);
 700         overwrite_slist(new, &tmp_slist);
 701
 702         merge_slist(&res, tmp_slist);
 703
 704         push_slist(slist_stack, res);
 705         free_slist(&tmp_slist);
 706         free_slist(&new);
 707         free_slist(&old);
 708 }
 709
 710 /*
 711  * get_slist_from_named_stack() is only used for gotos.
 712  */
 713 struct state_list **get_slist_from_named_stack(struct named_stack *stack,
 714                                               const char *name)
 715 {
 716         struct named_slist *tmp;
 717
 718         FOR_EACH_PTR(stack, tmp) {
 719                 if (!strcmp(tmp->name, name))
 720                         return &tmp->slist;
 721         } END_FOR_EACH_PTR(tmp);
 722         return NULL;
 723 }
 724
 725 void overwrite_slist(struct state_list *from, struct state_list **to)
 726 {
 727         struct sm_state *tmp;
 728
 729         FOR_EACH_PTR(from, tmp) {
 730                 overwrite_sm_state(to, tmp);
 731         } END_FOR_EACH_PTR(tmp);
 732 }