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