smatch_extra.c

   1 /*
   2  * sparse/smatch_extra.c
   3  *
   4  * Copyright (C) 2008 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * smatch_extra.c is supposed to track the value of every variable.
  12  *
  13  */
  14
  15 #include <stdlib.h>
  16 #include <errno.h>
  17 #ifndef __USE_ISOC99
  18 #define __USE_ISOC99
  19 #endif
  20 #include <limits.h>
  21 #include "parse.h"
  22 #include "smatch.h"
  23 #include "smatch_slist.h"
  24 #include "smatch_extra.h"
  25
  26 static int my_id;
  27
  28 struct string_list *__ignored_macros = NULL;
  29 static int in_warn_on_macro()
  30 {
  31         struct statement *stmt;
  32         char *tmp;
  33         char *macro;
  34
  35         stmt = get_current_statement();
  36         macro = get_macro_name(stmt->pos);
  37         if (!macro)
  38                 return 0;
  39
  40         FOR_EACH_PTR(__ignored_macros, tmp) {
  41                 if (!strcmp(tmp, macro))
  42                         return 1;
  43         } END_FOR_EACH_PTR(tmp);
  44         return 0;
  45 }
  46
  47 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
  48 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
  49 static struct void_fn_list *extra_mod_hooks;
  50 void add_extra_mod_hook(mod_hook *fn)
  51 {
  52         mod_hook **p = malloc(sizeof(mod_hook *));
  53         *p = fn;
  54         add_ptr_list(&extra_mod_hooks, p);
  55 }
  56
  57 static void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
  58 {
  59         mod_hook **fn;
  60
  61         FOR_EACH_PTR(extra_mod_hooks, fn) {
  62                 (*fn)(name, sym, state);
  63         } END_FOR_EACH_PTR(fn);
  64 }
  65
  66 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
  67 {
  68         if (in_warn_on_macro())
  69                 return NULL;
  70         remove_from_equiv(name, sym);
  71         call_extra_mod_hooks(name, sym, state);
  72         return set_state(SMATCH_EXTRA, name, sym, state);
  73 }
  74
  75 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
  76 {
  77         struct symbol *sym;
  78         char *name;
  79         struct sm_state *ret = NULL;
  80
  81         expr = strip_expr(expr);
  82         name = get_variable_from_expr(expr, &sym);
  83         if (!name || !sym)
  84                 goto free;
  85         ret = set_extra_mod(name, sym, state);
  86 free:
  87         free_string(name);
  88         return ret;
  89 }
  90
  91 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
  92 {
  93         struct relation *rel;
  94         struct smatch_state *orig_state;
  95
  96         orig_state = get_state(SMATCH_EXTRA, name, sym);
  97
  98         if (!estate_related(orig_state)) {
  99                 set_state(SMATCH_EXTRA, name, sym, state);
 100                 return;
 101         }
 102
 103         set_related(state, estate_related(orig_state));
 104         FOR_EACH_PTR(estate_related(orig_state), rel) {
 105                 if (option_debug_related)
 106                         sm_msg("updating related %s to %s", rel->name, state->name);
 107                 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
 108         } END_FOR_EACH_PTR(rel);
 109 }
 110
 111 /*
 112  * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
 113  */
 114 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
 115 {
 116         char *name;
 117         struct symbol *sym;
 118
 119         name = get_variable_from_expr(expr, &sym);
 120         if (!name || !sym)
 121                 goto free;
 122         set_extra_nomod(name, sym, state);
 123 free:
 124         free_string(name);
 125
 126 }
 127
 128 static void set_extra_true_false(const char *name, struct symbol *sym,
 129                         struct smatch_state *true_state,
 130                         struct smatch_state *false_state)
 131 {
 132         struct relation *rel;
 133         struct smatch_state *orig_state;
 134
 135         if (in_warn_on_macro())
 136                 return;
 137
 138         orig_state = get_state(SMATCH_EXTRA, name, sym);
 139
 140         if (!estate_related(orig_state)) {
 141                 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
 142                 return;
 143         }
 144
 145         if (true_state)
 146                 set_related(true_state, estate_related(orig_state));
 147         if (false_state)
 148                 set_related(false_state, estate_related(orig_state));
 149
 150         FOR_EACH_PTR(estate_related(orig_state), rel) {
 151                 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
 152                                 true_state, false_state);
 153         } END_FOR_EACH_PTR(rel);
 154 }
 155
 156 static void set_extra_expr_true_false(struct expression *expr,
 157                 struct smatch_state *true_state,
 158                 struct smatch_state *false_state)
 159 {
 160         char *name;
 161         struct symbol *sym;
 162
 163         expr = strip_expr(expr);
 164         name = get_variable_from_expr(expr, &sym);
 165         if (!name || !sym)
 166                 goto free;
 167         set_extra_true_false(name, sym, true_state, false_state);
 168 free:
 169         free_string(name);
 170 }
 171
 172 struct smatch_state *filter_range(struct smatch_state *orig,
 173                                  sval_t filter_min, sval_t filter_max)
 174 {
 175         struct range_list *rl;
 176
 177         if (!orig)
 178                 orig = alloc_estate_whole(filter_min.type);
 179
 180         rl = remove_range(estate_rl(orig), filter_min, filter_max);
 181         return alloc_estate_rl(rl);
 182 }
 183
 184 struct smatch_state *add_filter(struct smatch_state *orig, sval_t sval)
 185 {
 186         return filter_range(orig, sval, sval);
 187 }
 188
 189 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 190 {
 191         struct expression *iter_var;
 192         struct expression *condition;
 193         struct sm_state *sm;
 194         struct smatch_state *estate;
 195         sval_t start;
 196
 197         condition = strip_expr(loop->iterator_pre_condition);
 198         if (!condition)
 199                 return NULL;
 200         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 201                 return NULL;
 202         if (condition->op != SPECIAL_DECREMENT)
 203                 return NULL;
 204
 205         iter_var = condition->unop;
 206         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 207         if (!sm)
 208                 return NULL;
 209         if (sval_cmp_val(estate_min(sm->state), 0) < 0)
 210                 return NULL;
 211         start = estate_max(sm->state);
 212         if  (sval_cmp_val(start, 0) <= 0)
 213                 return NULL;
 214         if (!sval_is_max(start))
 215                 start.value--;
 216
 217         if (condition->type == EXPR_PREOP) {
 218                 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
 219                 if (estate_has_hard_max(sm->state))
 220                         estate_set_hard_max(estate);
 221                 set_extra_expr_mod(iter_var, estate);
 222         }
 223         if (condition->type == EXPR_POSTOP) {
 224                 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
 225                 if (estate_has_hard_max(sm->state))
 226                         estate_set_hard_max(estate);
 227                 set_extra_expr_mod(iter_var, estate);
 228         }
 229         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 230 }
 231
 232 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 233                                                 struct expression *condition)
 234 {
 235         struct expression *iter_var;
 236         struct sm_state *sm;
 237         struct smatch_state *estate;
 238         sval_t start, end, dummy;
 239
 240         iter_var = iter_expr->unop;
 241         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 242         if (!sm)
 243                 return NULL;
 244         if (!estate_get_single_value(sm->state, &start))
 245                 return NULL;
 246         if (!get_implied_max(condition->right, &end))
 247                 end = sval_type_max(get_type(iter_var));
 248
 249         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 250                 return NULL;
 251
 252         switch (condition->op) {
 253         case SPECIAL_NOTEQUAL:
 254         case '<':
 255                 if (!sval_is_min(end))
 256                         end.value--;
 257                 break;
 258         case SPECIAL_LTE:
 259                 break;
 260         default:
 261                 return NULL;
 262         }
 263         if (sval_cmp(end, start) < 0)
 264                 return NULL;
 265         estate = alloc_estate_range(start, end);
 266         if (get_hard_max(condition->right, &dummy))
 267                 estate_set_hard_max(estate);
 268         set_extra_expr_mod(iter_var, estate);
 269         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 270 }
 271
 272 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 273                                                 struct expression *condition)
 274 {
 275         struct expression *iter_var;
 276         struct sm_state *sm;
 277         struct smatch_state *estate;
 278         sval_t start, end;
 279
 280         iter_var = iter_expr->unop;
 281         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 282         if (!sm)
 283                 return NULL;
 284         if (!estate_get_single_value(sm->state, &start))
 285                 return NULL;
 286         if (!get_implied_min(condition->right, &end))
 287                 end = sval_type_min(get_type(iter_var));
 288         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 289                 return NULL;
 290
 291         switch (condition->op) {
 292         case SPECIAL_NOTEQUAL:
 293         case '>':
 294                 if (!sval_is_min(end) && !sval_is_max(end))
 295                         end.value++;
 296                 break;
 297         case SPECIAL_GTE:
 298                 break;
 299         default:
 300                 return NULL;
 301         }
 302         if (sval_cmp(end, start) > 0)
 303                 return NULL;
 304         estate = alloc_estate_range(end, start);
 305         estate_set_hard_max(estate);
 306         set_extra_expr_mod(iter_var, estate);
 307         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 308 }
 309
 310 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 311 {
 312         struct expression *iter_expr;
 313         struct expression *condition;
 314
 315         if (!loop->iterator_post_statement)
 316                 return NULL;
 317         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 318                 return NULL;
 319         iter_expr = loop->iterator_post_statement->expression;
 320         if (!loop->iterator_pre_condition)
 321                 return NULL;
 322         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 323                 return NULL;
 324         condition = loop->iterator_pre_condition;
 325
 326         if (iter_expr->op == SPECIAL_INCREMENT)
 327                 return handle_canonical_for_inc(iter_expr, condition);
 328         if (iter_expr->op == SPECIAL_DECREMENT)
 329                 return handle_canonical_for_dec(iter_expr, condition);
 330         return NULL;
 331 }
 332
 333 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 334 {
 335         struct sm_state *ret;
 336
 337         __push_fake_cur_slist();
 338         if (!loop->iterator_post_statement)
 339                 ret = handle_canonical_while_count_down(loop);
 340         else
 341                 ret = handle_canonical_for_loops(loop);
 342         *slist = __pop_fake_cur_slist();
 343         return ret;
 344 }
 345
 346 int __iterator_unchanged(struct sm_state *sm)
 347 {
 348         if (!sm)
 349                 return 0;
 350         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 351                 return 1;
 352         return 0;
 353 }
 354
 355 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 356 {
 357         sval_t after_value;
 358
 359         /* paranoid checking.  prolly not needed */
 360         condition = strip_expr(condition);
 361         if (!condition)
 362                 return;
 363         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 364                 return;
 365         if (condition->op != SPECIAL_DECREMENT)
 366                 return;
 367         after_value = estate_min(sm->state);
 368         after_value.value--;
 369         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
 370 }
 371
 372 void __extra_pre_loop_hook_after(struct sm_state *sm,
 373                                 struct statement *iterator,
 374                                 struct expression *condition)
 375 {
 376         struct expression *iter_expr;
 377         sval_t limit;
 378         struct smatch_state *state;
 379
 380         if (!iterator) {
 381                 while_count_down_after(sm, condition);
 382                 return;
 383         }
 384
 385         iter_expr = iterator->expression;
 386
 387         if (condition->type != EXPR_COMPARE)
 388                 return;
 389         if (iter_expr->op == SPECIAL_INCREMENT) {
 390                 limit = sval_binop(estate_max(sm->state), '+',
 391                                    sval_type_val(estate_type(sm->state), 1));
 392         } else {
 393                 limit = sval_binop(estate_min(sm->state), '-',
 394                                    sval_type_val(estate_type(sm->state), 1));
 395         }
 396         if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
 397                 if (iter_expr->op == SPECIAL_INCREMENT)
 398                         state = alloc_estate_range(estate_min(sm->state), limit);
 399                 else
 400                         state = alloc_estate_range(limit, estate_max(sm->state));
 401         } else {
 402                 state = alloc_estate_sval(limit);
 403         }
 404         if (!estate_has_hard_max(sm->state))
 405                 estate_clear_hard_max(state);
 406         set_extra_mod(sm->name, sm->sym, state);
 407 }
 408
 409 static struct state_list *unmatched_slist;
 410 static struct smatch_state *unmatched_state(struct sm_state *sm)
 411 {
 412         struct smatch_state *state;
 413
 414         if (unmatched_slist) {
 415                 state = get_state_slist(unmatched_slist, SMATCH_EXTRA, sm->name, sm->sym);
 416                 if (state)
 417                         return state;
 418         }
 419         return alloc_estate_whole(estate_type(sm->state));
 420 }
 421
 422 static void match_function_call(struct expression *expr)
 423 {
 424         struct expression *arg;
 425         struct expression *tmp;
 426
 427         FOR_EACH_PTR(expr->args, arg) {
 428                 tmp = strip_expr(arg);
 429                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 430                         remove_from_equiv_expr(tmp->unop);
 431                         set_state_expr(SMATCH_EXTRA, tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
 432                 }
 433         } END_FOR_EACH_PTR(arg);
 434 }
 435
 436 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 437 {
 438         if (!one || !two)
 439                 return 0;
 440         if (one->type == SYM_PTR && two->type == SYM_PTR)
 441                 return 1;
 442         return types_equiv(one, two);
 443 }
 444
 445 static void match_assign(struct expression *expr)
 446 {
 447         struct range_list *rl = NULL;
 448         struct expression *left;
 449         struct expression *right;
 450         struct symbol *right_sym;
 451         char *right_name = NULL;
 452         struct symbol *sym;
 453         char *name;
 454         sval_t value;
 455         int known;
 456         sval_t right_min, right_max;
 457         sval_t tmp;
 458
 459         if (is_condition(expr->right))
 460                 return;
 461         left = strip_expr(expr->left);
 462         name = get_variable_from_expr(left, &sym);
 463         if (!name)
 464                 return;
 465         right = strip_parens(expr->right);
 466         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 467                 right = strip_parens(right->left);
 468
 469         if (expr->op == '=' && right->type == EXPR_CALL)
 470                 goto free;  /* these are handled in smatch_function_hooks.c */
 471
 472         right_name = get_variable_from_expr(right, &right_sym);
 473         if (expr->op == '=' && right_name && right_sym &&
 474             types_equiv_or_pointer(get_type(expr->left), get_type(expr->right))) {
 475                 set_equiv(left, right);
 476                 goto free;
 477         }
 478
 479         right_min = sval_type_min(get_type(expr->right));
 480         right_max = sval_type_max(get_type(expr->right));
 481
 482         known = get_implied_value(right, &value);
 483         switch (expr->op) {
 484         case '=': {
 485                 struct smatch_state *state;
 486
 487                 if (get_implied_rl(right, &rl)) {
 488                         rl = cast_rl(get_type(expr->left), rl);
 489                         state = alloc_estate_rl(rl);
 490                         if (get_hard_max(right, &tmp))
 491                                 estate_set_hard_max(state);
 492                 } else {
 493                         rl = alloc_whole_rl(get_type(right));
 494                         rl = cast_rl(get_type(expr->left), rl);
 495                         state = alloc_estate_rl(rl);
 496                 }
 497                 set_extra_mod(name, sym, state);
 498                 goto free;
 499         }
 500         case SPECIAL_ADD_ASSIGN:
 501                 if (get_implied_min(left, &tmp)) {
 502                         if (known)
 503                                 right_min = sval_binop(tmp, '+', value);
 504                         else
 505                                 right_min = tmp;
 506                 }
 507                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 508                         right_max = sval_binop(tmp, '+', value);
 509                 break;
 510         case SPECIAL_SUB_ASSIGN:
 511                 if (get_implied_max(left, &tmp)) {
 512                         if (known)
 513                                 right_max = sval_binop(tmp, '-', value);
 514                         else
 515                                 right_max = tmp;
 516                 }
 517                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 518                         right_min = sval_binop(tmp, '-', value);
 519                 break;
 520         }
 521         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 522                 rl = cast_rl(get_type(expr->left), alloc_rl(right_min, right_max));
 523         else
 524                 rl = alloc_whole_rl(get_type(expr->left));
 525         set_extra_mod(name, sym, alloc_estate_rl(rl));
 526 free:
 527         free_string(right_name);
 528         free_string(name);
 529 }
 530
 531 static void reset_struct_members(struct sm_state *sm)
 532 {
 533         set_extra_mod(sm->name, sm->sym, alloc_estate_whole(estate_type(sm->state)));
 534 }
 535
 536 static struct smatch_state *increment_state(struct smatch_state *state)
 537 {
 538         sval_t min = estate_min(state);
 539         sval_t max = estate_max(state);
 540
 541         if (!estate_rl(state))
 542                 return NULL;
 543
 544         if (inside_loop())
 545                 max = sval_type_max(max.type);
 546
 547         if (!sval_is_min(min) && !sval_is_max(min))
 548                 min.value++;
 549         if (!sval_is_min(max) && !sval_is_max(max))
 550                 max.value++;
 551         return alloc_estate_range(min, max);
 552 }
 553
 554 static struct smatch_state *decrement_state(struct smatch_state *state)
 555 {
 556         sval_t min = estate_min(state);
 557         sval_t max = estate_max(state);
 558
 559         if (!estate_rl(state))
 560                 return NULL;
 561
 562         if (inside_loop())
 563                 min = sval_type_min(min.type);
 564
 565         if (!sval_is_min(min) && !sval_is_max(min))
 566                 min.value--;
 567         if (!sval_is_min(max) && !sval_is_max(max))
 568                 max.value--;
 569         return alloc_estate_range(min, max);
 570 }
 571
 572 static void unop_expr(struct expression *expr)
 573 {
 574         struct smatch_state *state;
 575
 576         if (expr->smatch_flags & Handled)
 577                 return;
 578
 579         switch (expr->op) {
 580         case SPECIAL_INCREMENT:
 581                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 582                 state = increment_state(state);
 583                 if (!state)
 584                         state = alloc_estate_whole(get_type(expr));
 585                 set_extra_expr_mod(expr->unop, state);
 586                 break;
 587         case SPECIAL_DECREMENT:
 588                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 589                 state = decrement_state(state);
 590                 if (!state)
 591                         state = alloc_estate_whole(get_type(expr));
 592                 set_extra_expr_mod(expr->unop, state);
 593                 break;
 594         default:
 595                 return;
 596         }
 597 }
 598
 599 static void asm_expr(struct statement *stmt)
 600 {
 601
 602         struct expression *expr;
 603         int state = 0;
 604
 605         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 606                 switch (state) {
 607                 case 0: /* identifier */
 608                 case 1: /* constraint */
 609                         state++;
 610                         continue;
 611                 case 2: /* expression */
 612                         state = 0;
 613                         set_extra_expr_mod(expr, alloc_estate_whole(get_type(expr)));
 614                         continue;
 615                 }
 616         } END_FOR_EACH_PTR(expr);
 617 }
 618
 619 static void delete_state_tracker(struct tracker *t)
 620 {
 621         remove_from_equiv(t->name, t->sym);
 622         delete_state(t->owner, t->name, t->sym);
 623 }
 624
 625 static void scoped_state_extra(const char *name, struct symbol *sym)
 626 {
 627         struct tracker *t;
 628
 629         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 630         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 631 }
 632
 633 static void match_declarations(struct symbol *sym)
 634 {
 635         const char *name;
 636
 637         if (sym->ident) {
 638                 name = sym->ident->name;
 639                 if (!sym->initializer) {
 640                         set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
 641                         scoped_state_extra(name, sym);
 642                 }
 643         }
 644 }
 645
 646 static void check_dereference(struct expression *expr)
 647 {
 648         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 649 }
 650
 651 static void match_dereferences(struct expression *expr)
 652 {
 653         if (expr->type != EXPR_PREOP)
 654                 return;
 655         check_dereference(expr->unop);
 656 }
 657
 658 static void match_pointer_as_array(struct expression *expr)
 659 {
 660         if (!is_array(expr))
 661                 return;
 662         check_dereference(expr->unop->left);
 663 }
 664
 665 static void set_param_dereferenced(struct expression *arg, char *unused)
 666 {
 667         check_dereference(arg);
 668 }
 669
 670 static void match_function_def(struct symbol *sym)
 671 {
 672         struct symbol *arg;
 673
 674         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 675                 if (!arg->ident)
 676                         continue;
 677                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 678         } END_FOR_EACH_PTR(arg);
 679 }
 680
 681 static int match_func_comparison(struct expression *expr)
 682 {
 683         struct expression *left = strip_expr(expr->left);
 684         struct expression *right = strip_expr(expr->right);
 685         sval_t sval;
 686
 687         if (left->type == EXPR_CALL) {
 688                 if (!get_implied_value(right, &sval))
 689                         return 1;
 690                 function_comparison(expr->op, left, sval, 1);
 691                 return 1;
 692         }
 693
 694         if (right->type == EXPR_CALL) {
 695                 if (!get_implied_value(left, &sval))
 696                         return 1;
 697                 function_comparison(expr->op, right, sval, 0);
 698                 return 1;
 699         }
 700
 701         return 0;
 702 }
 703
 704 static sval_t add_one(sval_t sval)
 705 {
 706         sval.value++;
 707         return sval;
 708 }
 709
 710 static sval_t sub_one(sval_t sval)
 711 {
 712         sval.value--;
 713         return sval;
 714 }
 715
 716 static void match_comparison(struct expression *expr)
 717 {
 718         struct expression *left = strip_expr(expr->left);
 719         struct expression *right = strip_expr(expr->right);
 720         struct symbol *type;
 721         struct range_list *left_orig;
 722         struct range_list *left_true;
 723         struct range_list *left_false;
 724         struct range_list *right_orig;
 725         struct range_list *right_true;
 726         struct range_list *right_false;
 727         struct smatch_state *left_true_state;
 728         struct smatch_state *left_false_state;
 729         struct smatch_state *right_true_state;
 730         struct smatch_state *right_false_state;
 731         sval_t min, max, dummy;
 732         int left_postop = 0;
 733         int right_postop = 0;
 734
 735         if (match_func_comparison(expr))
 736                 return;
 737
 738         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 739                 if (left->type == EXPR_POSTOP) {
 740                         left->smatch_flags |= Handled;
 741                         left_postop = left->op;
 742                 }
 743                 left = strip_expr(left->unop);
 744         }
 745         while (left->type == EXPR_ASSIGNMENT)
 746                 left = strip_expr(left->left);
 747
 748         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 749                 if (right->type == EXPR_POSTOP) {
 750                         right->smatch_flags |= Handled;
 751                         right_postop = right->op;
 752                 }
 753                 right = strip_expr(right->unop);
 754         }
 755
 756         type = get_type(expr);
 757         if (!type)
 758                 type = &llong_ctype;
 759
 760         if (get_implied_rl(left, &left_orig)) {
 761                 left_orig = cast_rl(type, left_orig);
 762         } else {
 763                 min = sval_type_min(get_type(left));
 764                 max = sval_type_max(get_type(left));
 765                 left_orig = cast_rl(type, alloc_rl(min, max));
 766         }
 767
 768         if (get_implied_rl(right, &right_orig)) {
 769                 right_orig = cast_rl(type, right_orig);
 770         } else {
 771                 min = sval_type_min(get_type(right));
 772                 max = sval_type_max(get_type(right));
 773                 right_orig = cast_rl(type, alloc_rl(min, max));
 774         }
 775         min = sval_type_min(type);
 776         max = sval_type_max(type);
 777
 778         left_true = clone_rl(left_orig);
 779         left_false = clone_rl(left_orig);
 780         right_true = clone_rl(right_orig);
 781         right_false = clone_rl(right_orig);
 782
 783         switch (expr->op) {
 784         case '<':
 785         case SPECIAL_UNSIGNED_LT:
 786                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 787                 if (!sval_is_min(rl_min(right_orig))) {
 788                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 789                 }
 790
 791                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 792                 if (!sval_is_max(rl_max(left_orig)))
 793                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 794                 break;
 795         case SPECIAL_UNSIGNED_LTE:
 796         case SPECIAL_LTE:
 797                 if (!sval_is_max(rl_max(right_orig)))
 798                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 799                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 800
 801                 if (!sval_is_min(rl_min(left_orig)))
 802                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 803                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 804
 805                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 806                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 807                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 808                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 809                 break;
 810         case SPECIAL_EQUAL:
 811                 if (!sval_is_max(rl_max(right_orig))) {
 812                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 813                 }
 814                 if (!sval_is_min(rl_min(right_orig))) {
 815                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 816                 }
 817                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 818                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 819
 820                 if (!sval_is_max(rl_max(left_orig)))
 821                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 822                 if (!sval_is_min(rl_min(left_orig)))
 823                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 824                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 825                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 826                 break;
 827         case SPECIAL_UNSIGNED_GTE:
 828         case SPECIAL_GTE:
 829                 if (!sval_is_min(rl_min(right_orig)))
 830                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 831                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 832
 833                 if (!sval_is_max(rl_max(left_orig)))
 834                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 835                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 836
 837                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 838                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 839                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 840                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 841                 break;
 842         case '>':
 843         case SPECIAL_UNSIGNED_GT:
 844                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 845                 if (!sval_is_max(rl_max(right_orig)))
 846                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 847
 848                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 849                 if (!sval_is_min(rl_min(left_orig)))
 850                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 851                 break;
 852         case SPECIAL_NOTEQUAL:
 853                 if (!sval_is_max(rl_max(right_orig)))
 854                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 855                 if (!sval_is_min(rl_min(right_orig)))
 856                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 857                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 858                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 859
 860                 if (!sval_is_max(rl_max(left_orig)))
 861                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 862                 if (!sval_is_min(rl_min(left_orig)))
 863                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 864                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 865                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 866                 break;
 867         default:
 868                 return;
 869         }
 870
 871         left_true_state = alloc_estate_rl(cast_rl(get_type(left), left_true));
 872         left_false_state = alloc_estate_rl(cast_rl(get_type(left), left_false));
 873         right_true_state = alloc_estate_rl(cast_rl(get_type(right), right_true));
 874         right_false_state = alloc_estate_rl(cast_rl(get_type(right), right_false));
 875
 876         switch (expr->op) {
 877         case '<':
 878         case SPECIAL_UNSIGNED_LT:
 879         case SPECIAL_UNSIGNED_LTE:
 880         case SPECIAL_LTE:
 881                 if (get_hard_max(right, &dummy))
 882                         estate_set_hard_max(left_true_state);
 883                 if (get_hard_max(left, &dummy))
 884                         estate_set_hard_max(right_false_state);
 885                 break;
 886         case '>':
 887         case SPECIAL_UNSIGNED_GT:
 888         case SPECIAL_UNSIGNED_GTE:
 889         case SPECIAL_GTE:
 890                 if (get_hard_max(left, &dummy))
 891                         estate_set_hard_max(right_true_state);
 892                 if (get_hard_max(right, &dummy))
 893                         estate_set_hard_max(left_false_state);
 894                 break;
 895         }
 896
 897         if (get_hard_max(left, &dummy)) {
 898                 estate_set_hard_max(left_true_state);
 899                 estate_set_hard_max(left_false_state);
 900         }
 901         if (get_hard_max(right, &dummy)) {
 902                 estate_set_hard_max(right_true_state);
 903                 estate_set_hard_max(right_false_state);
 904         }
 905
 906         if (left_postop == SPECIAL_INCREMENT) {
 907                 left_true_state = increment_state(left_true_state);
 908                 left_false_state = increment_state(left_false_state);
 909         }
 910         if (left_postop == SPECIAL_DECREMENT) {
 911                 left_true_state = decrement_state(left_true_state);
 912                 left_false_state = decrement_state(left_false_state);
 913         }
 914         if (right_postop == SPECIAL_INCREMENT) {
 915                 right_true_state = increment_state(right_true_state);
 916                 right_false_state = increment_state(right_false_state);
 917         }
 918         if (right_postop == SPECIAL_DECREMENT) {
 919                 right_true_state = decrement_state(right_true_state);
 920                 right_false_state = decrement_state(right_false_state);
 921         }
 922
 923         set_extra_expr_true_false(left, left_true_state, left_false_state);
 924         set_extra_expr_true_false(right, right_true_state, right_false_state);
 925 }
 926
 927 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 928 void __extra_match_condition(struct expression *expr)
 929 {
 930         struct symbol *sym;
 931         char *name;
 932         struct smatch_state *pre_state;
 933         struct smatch_state *true_state;
 934         struct smatch_state *false_state;
 935
 936         expr = strip_expr(expr);
 937         switch (expr->type) {
 938         case EXPR_CALL:
 939                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 940                 return;
 941         case EXPR_PREOP:
 942         case EXPR_SYMBOL:
 943         case EXPR_DEREF: {
 944                 sval_t zero;
 945
 946                 zero = sval_blank(expr);
 947                 zero.value = 0;
 948
 949                 name = get_variable_from_expr(expr, &sym);
 950                 if (!name)
 951                         return;
 952                 pre_state = get_state(my_id, name, sym);
 953                 true_state = add_filter(pre_state, zero);
 954                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 955                         false_state = alloc_estate_sval(zero);
 956                 else
 957                         false_state = alloc_estate_empty();
 958                 set_extra_true_false(name, sym, true_state, false_state);
 959                 free_string(name);
 960                 return;
 961         }
 962         case EXPR_COMPARE:
 963                 match_comparison(expr);
 964                 return;
 965         case EXPR_ASSIGNMENT:
 966                 __extra_match_condition(expr->left);
 967                 return;
 968         }
 969 }
 970
 971 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 972 int implied_not_equal(struct expression *expr, long long val)
 973 {
 974         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 975 }
 976
 977 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 978 {
 979         if (estate_is_whole(state))
 980                 return;
 981         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 982 }
 983
 984 static void db_limited_before(void)
 985 {
 986         unmatched_slist = clone_slist(__get_cur_slist());
 987 }
 988
 989 static void db_limited_after(void)
 990 {
 991         free_slist(&unmatched_slist);
 992 }
 993
 994 static char *get_variable_from_key(struct expression *arg, char *key, struct symbol **sym)
 995 {
 996         char buf[256];
 997         char *tmp;
 998
 999         if (strcmp(key, "$$") == 0)
1000                 return get_variable_from_expr(arg, sym);
1001
1002         if (strcmp(key, "*$$") == 0) {
1003                 if (arg->type == EXPR_PREOP && arg->op == '&') {
1004                         arg = strip_expr(arg->unop);
1005                         return get_variable_from_expr(arg, sym);
1006                 } else {
1007                         tmp = get_variable_from_expr(arg, sym);
1008                         if (!tmp)
1009                                 return NULL;
1010                         snprintf(buf, sizeof(buf), "*%s", tmp);
1011                         free_string(tmp);
1012                         return alloc_string(buf);
1013                 }
1014         }
1015
1016         if (arg->type == EXPR_PREOP && arg->op == '&') {
1017                 arg = strip_expr(arg->unop);
1018                 tmp = get_variable_from_expr(arg, sym);
1019                 if (!tmp)
1020                         return NULL;
1021                 snprintf(buf, sizeof(buf), "%s.%s", tmp, key + 4);
1022                 return alloc_string(buf);
1023         }
1024
1025         tmp = get_variable_from_expr(arg, sym);
1026         if (!tmp)
1027                 return NULL;
1028         snprintf(buf, sizeof(buf), "%s%s", tmp, key + 2);
1029         free_string(tmp);
1030         return alloc_string(buf);
1031 }
1032
1033 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value)
1034 {
1035         struct expression *arg;
1036         char *name;
1037         struct symbol *sym;
1038         struct sm_state *sm;
1039         struct symbol *type;
1040         struct range_list *rl;
1041         struct range_list *limit;
1042         struct range_list *new;
1043
1044         while (expr->type == EXPR_ASSIGNMENT)
1045                 expr = strip_expr(expr->right);
1046         if (expr->type != EXPR_CALL)
1047                 return;
1048
1049         arg = get_argument_from_call_expr(expr->args, param);
1050         if (!arg)
1051                 return;
1052
1053         name = get_variable_from_key(arg, key, &sym);
1054         if (!name || !sym)
1055                 goto free;
1056
1057         sm = get_sm_state(SMATCH_EXTRA, name, sym);
1058         type = get_member_type_from_key(arg, key);
1059         if (sm)
1060                 rl = estate_rl(sm->state);
1061         else
1062                 rl = alloc_whole_rl(type);
1063
1064         str_to_rl(type, value, &limit);
1065         new = rl_intersection(rl, limit);
1066
1067         /* We want to preserve the implications here */
1068         if (sm && rl_equiv(estate_rl(sm->state), new))
1069                 __set_sm(sm);
1070         else
1071                 set_extra_nomod(name, sym, alloc_estate_rl(new));
1072
1073 free:
1074         free_string(name);
1075 }
1076
1077 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1078 {
1079         struct expression *arg;
1080         char *name;
1081         struct symbol *sym;
1082         struct symbol *type;
1083         struct smatch_state *state;
1084         struct range_list *added = NULL;
1085         struct range_list *new;
1086
1087         while (expr->type == EXPR_ASSIGNMENT)
1088                 expr = strip_expr(expr->right);
1089         if (expr->type != EXPR_CALL)
1090                 return;
1091
1092         arg = get_argument_from_call_expr(expr->args, param);
1093         if (!arg)
1094                 return;
1095         name = get_variable_from_key(arg, key, &sym);
1096         if (!name || !sym)
1097                 goto free;
1098
1099         type = get_member_type_from_key(arg, key);
1100         state = get_state(SMATCH_EXTRA, name, sym);
1101         if (state) {
1102                 str_to_rl(type, value, &added);
1103                 new = rl_union(estate_rl(state), added);
1104         } else {
1105                 new = alloc_whole_rl(type);
1106         }
1107
1108         set_extra_mod(name, sym, alloc_estate_rl(new));
1109 free:
1110         free_string(name);
1111 }
1112
1113 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
1114 {
1115         struct expression *arg;
1116         struct symbol *type;
1117         struct range_list *rl;
1118         char member_name[256];
1119         char *name;
1120         struct symbol *sym;
1121
1122         while (expr->type == EXPR_ASSIGNMENT)
1123                 expr = strip_expr(expr->right);
1124         if (expr->type != EXPR_CALL)
1125                 return;
1126         arg = get_argument_from_call_expr(expr->args, param);
1127         arg = strip_expr(arg);
1128         if (!arg)
1129                 return;
1130
1131         if (strcmp(key, "*$$") == 0) {
1132                 struct symbol *sym;
1133                 char buf[256];
1134                 char *name;
1135
1136                 if (arg->type == EXPR_PREOP && arg->op == '&') {
1137                         arg = strip_expr(arg->unop);
1138                         name = get_variable_from_expr(arg, &sym);
1139                 } else {
1140                         char *tmp = get_variable_from_expr(arg, &sym);
1141
1142                         if (!tmp)
1143                                 return;
1144                         snprintf(buf, sizeof(buf), "*%s", tmp);
1145                         name = alloc_string(buf);
1146                         free_string(tmp);
1147                 }
1148                 if (!name || !sym) {
1149                         free_string(name);
1150                         return;
1151                 }
1152                 type = get_type(arg);
1153                 str_to_rl(type, value, &rl);
1154                 set_extra_mod(name, sym, alloc_estate_rl(rl));
1155                 free_string(name);
1156                 return;
1157         }
1158
1159         if (arg->type == EXPR_PREOP && arg->op == '&') {
1160                 arg = strip_expr(arg->unop);
1161                 name = get_variable_from_expr(arg, &sym);
1162                 if (!name || !sym)
1163                         goto free;
1164                 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
1165         } else {
1166                 name = get_variable_from_expr(arg, &sym);
1167                 if (!name || !sym)
1168                         goto free;
1169                 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1170         }
1171         type = get_member_type_from_key(arg, key);
1172         if (!type)
1173                 goto free;
1174         str_to_rl(type, value, &rl);
1175         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1176 free:
1177         free_string(name);
1178 }
1179
1180 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1181 {
1182         struct symbol *type;
1183         struct symbol *sym;
1184         char *name;
1185         char member_name[256];
1186         struct range_list *rl;
1187
1188         if (expr->type != EXPR_ASSIGNMENT)
1189                 return;
1190
1191         name = get_variable_from_expr(expr->left, &sym);
1192         if (!name || !sym)
1193                 goto free;
1194         snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1195         type = get_member_type_from_key(expr->left, key);
1196         if (!type)
1197                 return;
1198         str_to_rl(type, value, &rl);
1199         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1200
1201 free:
1202         free_string(name);
1203 }
1204
1205 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1206 {
1207         if (estate_is_whole(state))
1208                 return;
1209         sm_msg("info: return_value %d '%s' '%s' '%s' %s", return_id,
1210                return_ranges, printed_name, state->name, global_static());
1211 }
1212
1213 static void match_call_info(struct expression *expr)
1214 {
1215         struct range_list *rl = NULL;
1216         struct expression *arg;
1217         struct symbol *type;
1218         char *name;
1219         int i = 0;
1220
1221         name = get_fnptr_name(expr->fn);
1222         if (!name)
1223                 return;
1224
1225         FOR_EACH_PTR(expr->args, arg) {
1226                 type = get_arg_type(expr->fn, i);
1227
1228                 if (get_implied_rl(arg, &rl))
1229                         rl = cast_rl(type, rl);
1230                 else
1231                         rl = alloc_whole_rl(type);
1232
1233                 sm_msg("info: passes param_value '%s' %d '$$' %s %s",
1234                        name, i, show_ranges(rl),
1235                        is_static(expr->fn) ? "static" : "global");
1236                 i++;
1237         } END_FOR_EACH_PTR(arg);
1238
1239         free_string(name);
1240 }
1241
1242 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1243 {
1244         struct range_list *rl = NULL;
1245         struct smatch_state *state;
1246         struct symbol *type;
1247         char fullname[256];
1248
1249         if (strncmp(key, "$$", 2))
1250                 return;
1251
1252         snprintf(fullname, 256, "%s%s", name, key + 2);
1253         type = get_member_type_from_key(symbol_expression(sym), key);
1254         str_to_rl(type, value, &rl);
1255         state = alloc_estate_rl(rl);
1256         set_state(SMATCH_EXTRA, fullname, sym, state);
1257 }
1258
1259 void register_smatch_extra(int id)
1260 {
1261         my_id = id;
1262
1263         add_merge_hook(my_id, &merge_estates);
1264         add_unmatched_state_hook(my_id, &unmatched_state);
1265         add_hook(&match_function_def, FUNC_DEF_HOOK);
1266         add_hook(&match_declarations, DECLARATION_HOOK);
1267         add_definition_db_callback(set_param_value, PARAM_VALUE);
1268         add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1269         add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1270         add_db_return_states_before(&db_limited_before);
1271         add_db_return_states_callback(LIMITED_VALUE, &db_param_limit_filter);
1272         add_db_return_states_callback(FILTER_VALUE, &db_param_limit_filter);
1273         add_db_return_states_callback(ADDED_VALUE, &db_param_add);
1274         add_db_return_states_after(&db_limited_after);
1275 }
1276
1277 void register_smatch_extra_late(int id)
1278 {
1279         add_hook(&match_dereferences, DEREF_HOOK);
1280         add_hook(&match_pointer_as_array, OP_HOOK);
1281         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1282         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1283         if (option_no_db)
1284                 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1285         add_hook(&match_assign, ASSIGNMENT_HOOK);
1286         add_hook(&unop_expr, OP_HOOK);
1287         add_hook(&asm_expr, ASM_HOOK);
1288
1289         if (option_info) {
1290                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1291                 add_member_info_callback(my_id, struct_member_callback);
1292                 add_returned_member_callback(my_id, returned_member_callback);
1293         }
1294 }