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 = last_ptr_list((struct ptr_list *)big_statement_stack);
  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 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
  48 {
  49         if (in_warn_on_macro())
  50                 return NULL;
  51         remove_from_equiv(name, sym);
  52         return set_state(SMATCH_EXTRA, name, sym, state);
  53 }
  54
  55 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
  56 {
  57         if (in_warn_on_macro())
  58                 return NULL;
  59         remove_from_equiv_expr(expr);
  60         return set_state_expr(SMATCH_EXTRA, expr, state);
  61 }
  62
  63 /*
  64  * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
  65  */
  66 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
  67 {
  68         struct relation *rel;
  69         struct smatch_state *orig_state;
  70
  71         orig_state = get_state_expr(SMATCH_EXTRA, expr);
  72
  73         if (!orig_state || !get_dinfo(orig_state)->related) {
  74                 set_state_expr(SMATCH_EXTRA, expr, state);
  75                 return;
  76         }
  77
  78         FOR_EACH_PTR(get_dinfo(orig_state)->related, rel) {
  79                 sm_msg("setting %s to %s", rel->name, state->name);
  80                 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
  81                 add_equiv(state, rel->name, rel->sym);
  82         } END_FOR_EACH_PTR(rel);
  83 }
  84
  85 static void set_extra_true_false(const char *name, struct symbol *sym,
  86                         struct smatch_state *true_state,
  87                         struct smatch_state *false_state)
  88 {
  89         struct relation *rel;
  90         struct smatch_state *orig_state;
  91
  92         if (in_warn_on_macro())
  93                 return;
  94
  95         orig_state = get_state(SMATCH_EXTRA, name, sym);
  96
  97         if (!orig_state || !get_dinfo(orig_state)->related) {
  98                 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
  99                 return;
 100         }
 101
 102         // FIXME!!!!  equiv => related
 103         FOR_EACH_PTR(get_dinfo(orig_state)->related, rel) {
 104                 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
 105                                 true_state, false_state);
 106                 if (true_state)
 107                         add_equiv(true_state, rel->name, rel->sym);
 108                 if (false_state)
 109                         add_equiv(false_state, rel->name, rel->sym);
 110         } END_FOR_EACH_PTR(rel);
 111 }
 112
 113 static void set_extra_expr_true_false(struct expression *expr,
 114                 struct smatch_state *true_state,
 115                 struct smatch_state *false_state)
 116 {
 117         char *name;
 118         struct symbol *sym;
 119
 120         expr = strip_expr(expr);
 121         name = get_variable_from_expr(expr, &sym);
 122         if (!name || !sym)
 123                 goto free;
 124         set_extra_true_false(name, sym, true_state, false_state);
 125 free:
 126         free_string(name);
 127 }
 128
 129 struct data_info *get_dinfo(struct smatch_state *state)
 130 {
 131         if (!state)
 132                 return NULL;
 133         return (struct data_info *)state->data;
 134
 135 }
 136
 137 struct smatch_state *filter_range(struct smatch_state *orig,
 138                                  long long filter_min, long long filter_max)
 139 {
 140         struct smatch_state *ret;
 141         struct data_info *orig_info;
 142         struct data_info *ret_info;
 143
 144         if (!orig)
 145                 orig = extra_undefined();
 146         orig_info = get_dinfo(orig);
 147         ret = alloc_extra_state_empty();
 148         ret_info = get_dinfo(ret);
 149         ret_info->value_ranges = remove_range(orig_info->value_ranges, filter_min, filter_max);
 150         ret->name = show_ranges(ret_info->value_ranges);
 151         return ret;
 152 }
 153
 154 struct smatch_state *add_filter(struct smatch_state *orig, long long num)
 155 {
 156         return filter_range(orig, num, num);
 157 }
 158
 159 static struct smatch_state *merge_func(const char *name, struct symbol *sym,
 160                                        struct smatch_state *s1,
 161                                        struct smatch_state *s2)
 162 {
 163         struct data_info *info1 = get_dinfo(s1);
 164         struct data_info *info2 = get_dinfo(s2);
 165         struct data_info *ret_info;
 166         struct smatch_state *tmp;
 167         struct range_list *value_ranges;
 168         struct relation *rel;
 169         struct relation *new;
 170
 171         value_ranges = range_list_union(info1->value_ranges, info2->value_ranges);
 172         tmp = alloc_extra_state_empty();
 173         ret_info = get_dinfo(tmp);
 174         ret_info->value_ranges = value_ranges;
 175         tmp->name = show_ranges(ret_info->value_ranges);
 176         FOR_EACH_PTR(info1->related, rel) {
 177                 new = get_common_relationship(info2, rel->op, rel->name, rel->sym);
 178                 if (new)
 179                         add_related(tmp, new->op, new->name, new->sym);
 180         } END_FOR_EACH_PTR(rel);
 181         return tmp;
 182 }
 183
 184 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 185 {
 186         struct expression *iter_var;
 187         struct expression *condition;
 188         struct sm_state *sm;
 189         long long start;
 190
 191         condition = strip_expr(loop->iterator_pre_condition);
 192         if (!condition)
 193                 return NULL;
 194         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 195                 return NULL;
 196         if (condition->op != SPECIAL_DECREMENT)
 197                 return NULL;
 198
 199         iter_var = condition->unop;
 200         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 201         if (!sm)
 202                 return NULL;
 203         if (get_dinfo_min(get_dinfo(sm->state)) < 0)
 204                 return NULL;
 205         start = get_dinfo_max(get_dinfo(sm->state));
 206         if  (start <= 0)
 207                 return NULL;
 208         if (start != whole_range.max)
 209                 start--;
 210
 211         if (condition->type == EXPR_PREOP)
 212                 set_extra_expr_mod(iter_var, alloc_extra_state_range(1, start));
 213         if (condition->type == EXPR_POSTOP)
 214                 set_extra_expr_mod(iter_var, alloc_extra_state_range(0, start));
 215         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 216 }
 217
 218 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 219                                                 struct expression *condition)
 220 {
 221         struct expression *iter_var;
 222         struct sm_state *sm;
 223         long long start;
 224         long long end;
 225
 226         iter_var = iter_expr->unop;
 227         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 228         if (!sm)
 229                 return NULL;
 230         if (!get_single_value_from_dinfo(get_dinfo(sm->state), &start))
 231                 return NULL;
 232         if (!get_implied_value(condition->right, &end))
 233                 end = whole_range.max;
 234         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 235                 return NULL;
 236
 237         switch (condition->op) {
 238         case SPECIAL_NOTEQUAL:
 239         case '<':
 240                 if (end != whole_range.max)
 241                         end--;
 242                 break;
 243         case SPECIAL_LTE:
 244                 break;
 245         default:
 246                 return NULL;
 247         }
 248         if (end < start)
 249                 return NULL;
 250         set_extra_expr_mod(iter_var, alloc_extra_state_range(start, end));
 251         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 252 }
 253
 254 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 255                                                 struct expression *condition)
 256 {
 257         struct expression *iter_var;
 258         struct sm_state *sm;
 259         long long start;
 260         long long end;
 261
 262         iter_var = iter_expr->unop;
 263         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 264         if (!sm)
 265                 return NULL;
 266         if (!get_single_value_from_dinfo(get_dinfo(sm->state), &start))
 267                 return NULL;
 268         if (!get_implied_value(condition->right, &end))
 269                 end = whole_range.max;
 270         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 271                 return NULL;
 272
 273         switch (condition->op) {
 274         case SPECIAL_NOTEQUAL:
 275         case '>':
 276                 if (end != whole_range.min)
 277                         end++;
 278                 break;
 279         case SPECIAL_GTE:
 280                 break;
 281         default:
 282                 return NULL;
 283         }
 284         if (end > start)
 285                 return NULL;
 286         set_extra_expr_mod(iter_var, alloc_extra_state_range(end, start));
 287         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 288 }
 289
 290 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 291 {
 292         struct expression *iter_expr;
 293         struct expression *condition;
 294
 295         if (!loop->iterator_post_statement)
 296                 return NULL;
 297         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 298                 return NULL;
 299         iter_expr = loop->iterator_post_statement->expression;
 300         if (!loop->iterator_pre_condition)
 301                 return NULL;
 302         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 303                 return NULL;
 304         condition = loop->iterator_pre_condition;
 305
 306         if (iter_expr->op == SPECIAL_INCREMENT)
 307                 return handle_canonical_for_inc(iter_expr, condition);
 308         if (iter_expr->op == SPECIAL_DECREMENT)
 309                 return handle_canonical_for_dec(iter_expr, condition);
 310         return NULL;
 311 }
 312
 313 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 314 {
 315         struct sm_state *ret;
 316
 317         __push_fake_cur_slist();
 318         if (!loop->iterator_post_statement)
 319                 ret = handle_canonical_while_count_down(loop);
 320         else
 321                 ret = handle_canonical_for_loops(loop);
 322         *slist = __pop_fake_cur_slist();
 323         return ret;
 324 }
 325
 326 int __iterator_unchanged(struct sm_state *sm)
 327 {
 328         if (!sm)
 329                 return 0;
 330         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 331                 return 1;
 332         return 0;
 333 }
 334
 335 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 336 {
 337         long long after_value;
 338
 339         /* paranoid checking.  prolly not needed */
 340         condition = strip_expr(condition);
 341         if (!condition)
 342                 return;
 343         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 344                 return;
 345         if (condition->op != SPECIAL_DECREMENT)
 346                 return;
 347         after_value = get_dinfo_min(get_dinfo(sm->state));
 348         after_value--;
 349         set_extra_mod(sm->name, sm->sym, alloc_extra_state(after_value));
 350 }
 351
 352 void __extra_pre_loop_hook_after(struct sm_state *sm,
 353                                 struct statement *iterator,
 354                                 struct expression *condition)
 355 {
 356         struct expression *iter_expr;
 357         char *name;
 358         struct symbol *sym;
 359         long long value;
 360         int left = 0;
 361         struct smatch_state *state;
 362         struct data_info *dinfo;
 363         long long min, max;
 364
 365         if (!iterator) {
 366                 while_count_down_after(sm, condition);
 367                 return;
 368         }
 369
 370         iter_expr = iterator->expression;
 371
 372         if (condition->type != EXPR_COMPARE)
 373                 return;
 374         if (!get_value(condition->left, &value)) {
 375                 if (!get_value(condition->right, &value))
 376                         return;
 377                 left = 1;
 378         }
 379         if (left)
 380                 name = get_variable_from_expr(condition->left, &sym);
 381         else
 382                 name = get_variable_from_expr(condition->right, &sym);
 383         if (!name || !sym)
 384                 goto free;
 385         if (sym != sm->sym || strcmp(name, sm->name))
 386                 goto free;
 387         state = get_state(my_id, name, sym);
 388         dinfo = get_dinfo(state);
 389         min = get_dinfo_min(dinfo);
 390         max = get_dinfo_max(dinfo);
 391         if (iter_expr->op == SPECIAL_INCREMENT &&
 392                 min != whole_range.min &&
 393                 max == whole_range.max) {
 394                 set_extra_mod(name, sym, alloc_extra_state(min));
 395         } else if (min == whole_range.min && max != whole_range.max) {
 396                 set_extra_mod(name, sym, alloc_extra_state(max));
 397         }
 398 free:
 399         free_string(name);
 400         return;
 401 }
 402
 403 static struct smatch_state *unmatched_state(struct sm_state *sm)
 404 {
 405         return extra_undefined();
 406 }
 407
 408 static void match_function_call(struct expression *expr)
 409 {
 410         struct expression *tmp;
 411
 412         FOR_EACH_PTR(expr->args, tmp) {
 413                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 414                         remove_from_equiv_expr(tmp->unop);
 415                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined());
 416                 }
 417         } END_FOR_EACH_PTR(tmp);
 418 }
 419
 420 static void set_equiv(struct sm_state *right_sm, struct expression *left)
 421 {
 422         struct smatch_state *state;
 423         struct data_info *dinfo;
 424         struct relation *rel;
 425         char *name;
 426         struct symbol *sym;
 427
 428         name = get_variable_from_expr(left, &sym);
 429         if (!name || !sym)
 430                 goto free;
 431
 432         remove_from_equiv(name, sym);
 433
 434         state = clone_extra_state(right_sm->state);
 435         dinfo = get_dinfo(state);
 436         if (!dinfo->related)
 437                 add_equiv(state, right_sm->name, right_sm->sym);
 438         add_equiv(state, name, sym);
 439
 440         FOR_EACH_PTR(dinfo->related, rel) {
 441                 struct sm_state *new_sm;
 442
 443                 new_sm = clone_sm(right_sm);
 444                 new_sm->name = rel->name;
 445                 new_sm->sym = rel->sym;
 446                 new_sm->state = state;
 447                 __set_sm(new_sm);
 448         } END_FOR_EACH_PTR(rel);
 449 free:
 450         free_string(name);
 451 }
 452
 453 static void match_assign(struct expression *expr)
 454 {
 455         struct expression *left;
 456         struct expression *right;
 457         struct sm_state *right_sm;
 458         struct symbol *right_sym;
 459         char *right_name;
 460         struct symbol *sym;
 461         char *name;
 462         long long value;
 463         int known;
 464         long long min = whole_range.min;
 465         long long max = whole_range.max;
 466         long long tmp;
 467
 468         if (__is_condition_assign(expr))
 469                 return;
 470         left = strip_expr(expr->left);
 471         name = get_variable_from_expr(left, &sym);
 472         if (!name)
 473                 return;
 474         right = strip_parens(expr->right);
 475         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 476                 right = strip_parens(right->left);
 477
 478         if (expr->op == '=' && right->type == EXPR_CALL)
 479                 return;  /* these are handled in match_call_assign() */
 480
 481         right_name = get_variable_from_expr(right, &right_sym);
 482         if (expr->op == '=' && right_name && right_sym) {
 483                 right_sm = get_sm_state_expr(SMATCH_EXTRA, right);
 484                 if (!right_sm)
 485                         right_sm = set_state_expr(SMATCH_EXTRA, right, extra_undefined());
 486                 if (!right_sm)
 487                         goto free;
 488                 set_equiv(right_sm, left);
 489                 goto free;
 490         }
 491
 492         known = get_implied_value(right, &value);
 493         switch (expr->op) {
 494         case '=': {
 495                 struct range_list *rl = NULL;
 496
 497                 if (get_implied_range_list(right, &rl)) {
 498                         set_extra_mod(name, sym, alloc_extra_state_range_list(rl));
 499                         goto free;
 500                 }
 501
 502                 if (expr_unsigned(right))
 503                         min = 0;
 504                 break;
 505         }
 506         case SPECIAL_ADD_ASSIGN:
 507                 if (get_implied_min(left, &tmp)) {
 508                         if (known)
 509                                 min = tmp + value;
 510                         else
 511                                 min = tmp;
 512                 }
 513                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 514                                 max = tmp + value;
 515                 break;
 516         case SPECIAL_SUB_ASSIGN:
 517                 if (get_implied_max(left, &tmp)) {
 518                         if (known)
 519                                 max = tmp - value;
 520                         else
 521                                 max = tmp;
 522                 }
 523                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 524                                 min = tmp - value;
 525                 break;
 526         }
 527         set_extra_mod(name, sym, alloc_extra_state_range(min, max));
 528 free:
 529         free_string(right_name);
 530         free_string(name);
 531 }
 532
 533 static void reset_struct_members(const char *name, struct symbol *sym, struct expression *expr, void *unused)
 534 {
 535         struct state_list *slist;
 536         struct sm_state *tmp;
 537         int len;
 538
 539         len = strlen(name);
 540         slist = get_all_states(SMATCH_EXTRA);
 541         FOR_EACH_PTR(slist, tmp) {
 542                 if (sym != tmp->sym)
 543                         continue;
 544                 if (strncmp(name, tmp->name, len))
 545                         continue;
 546                 if (tmp->name[len] != '-' && tmp->name[len] != '.')
 547                         continue;
 548                 set_extra_mod(tmp->name, tmp->sym, extra_undefined());
 549         } END_FOR_EACH_PTR(tmp);
 550 }
 551
 552 static struct smatch_state *increment_state(struct smatch_state *state)
 553 {
 554         long long min;
 555         long long max;
 556
 557         min = get_dinfo_min(get_dinfo(state));
 558         max = get_dinfo_max(get_dinfo(state));
 559
 560         if (inside_loop())
 561                 max = whole_range.max;
 562
 563         if (min != whole_range.min)
 564                 min++;
 565         if (max != whole_range.max)
 566                 max++;
 567         return alloc_extra_state_range(min, max);
 568 }
 569
 570 static struct smatch_state *decrement_state(struct smatch_state *state)
 571 {
 572         long long min;
 573         long long max;
 574
 575         min = get_dinfo_min(get_dinfo(state));
 576         max = get_dinfo_max(get_dinfo(state));
 577
 578         if (inside_loop())
 579                 min = whole_range.min;
 580
 581         if (min != whole_range.min)
 582                 min--;
 583         if (max != whole_range.max)
 584                 max--;
 585         return alloc_extra_state_range(min, max);
 586 }
 587
 588 static void unop_expr(struct expression *expr)
 589 {
 590         struct smatch_state *state;
 591
 592         if (expr->smatch_flags & Handled)
 593                 return;
 594
 595         switch (expr->op) {
 596         case SPECIAL_INCREMENT:
 597                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 598                 state = increment_state(state);
 599                 set_extra_expr_mod(expr->unop, state);
 600                 break;
 601         case SPECIAL_DECREMENT:
 602                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 603                 state = decrement_state(state);
 604                 set_extra_expr_mod(expr->unop, state);
 605                 break;
 606         default:
 607                 return;
 608         }
 609 }
 610
 611 static void delete_state_tracker(struct tracker *t)
 612 {
 613         remove_from_equiv(t->name, t->sym);
 614         delete_state(t->owner, t->name, t->sym);
 615 }
 616
 617 static void scoped_state_extra(const char *name, struct symbol *sym)
 618 {
 619         struct tracker *t;
 620
 621         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 622         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 623 }
 624
 625 static void match_declarations(struct symbol *sym)
 626 {
 627         const char *name;
 628
 629         if (sym->ident) {
 630                 name = sym->ident->name;
 631                 if (!sym->initializer) {
 632                         set_state(SMATCH_EXTRA, name, sym, extra_undefined());
 633                         scoped_state_extra(name, sym);
 634                 }
 635         }
 636 }
 637
 638 static void match_function_def(struct symbol *sym)
 639 {
 640         struct symbol *arg;
 641
 642         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 643                 if (!arg->ident)
 644                         continue;
 645                 set_state(my_id, arg->ident->name, arg, extra_undefined());
 646         } END_FOR_EACH_PTR(arg);
 647 }
 648
 649 static int last_stmt_val(struct statement *stmt, long long *val)
 650 {
 651         struct expression *expr;
 652
 653         if (!stmt)
 654                 return 0;
 655
 656         stmt = last_ptr_list((struct ptr_list *)stmt->stmts);
 657         if (stmt->type != STMT_EXPRESSION)
 658                 return 0;
 659         expr = stmt->expression;
 660         return get_value(expr, val);
 661 }
 662
 663 static int match_func_comparison(struct expression *expr)
 664 {
 665         struct expression *left = strip_expr(expr->left);
 666         struct expression *right = strip_expr(expr->right);
 667         long long val;
 668
 669         if (left->type == EXPR_CALL) {
 670                 if (!get_implied_value(right, &val))
 671                         return 1;
 672                 function_comparison(expr->op, left, val, 1);
 673                 return 1;
 674         }
 675
 676         if (right->type == EXPR_CALL) {
 677                 if (!get_implied_value(left, &val))
 678                         return 1;
 679                 function_comparison(expr->op, right, val, 0);
 680                 return 1;
 681         }
 682
 683         return 0;
 684 }
 685
 686 static void match_comparison(struct expression *expr)
 687 {
 688         struct expression *left = strip_expr(expr->left);
 689         struct expression *right = strip_expr(expr->right);
 690         struct range_list *left_orig;
 691         struct range_list *left_true;
 692         struct range_list *left_false;
 693         struct range_list *right_orig;
 694         struct range_list *right_true;
 695         struct range_list *right_false;
 696         struct smatch_state *left_true_state;
 697         struct smatch_state *left_false_state;
 698         struct smatch_state *right_true_state;
 699         struct smatch_state *right_false_state;
 700         int left_postop = 0;
 701         int right_postop = 0;
 702
 703         if (match_func_comparison(expr))
 704                 return;
 705
 706         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 707                 if (left->type == EXPR_POSTOP) {
 708                         left->smatch_flags |= Handled;
 709                         left_postop = left->op;
 710                 }
 711                 left = strip_expr(left->unop);
 712         }
 713
 714         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 715                 if (right->type == EXPR_POSTOP) {
 716                         right->smatch_flags |= Handled;
 717                         right_postop = right->op;
 718                 }
 719                 right = strip_expr(right->unop);
 720         }
 721
 722         if (!get_implied_range_list(left, &left_orig))
 723                 left_orig = alloc_range_list(whole_range.min, whole_range.max);
 724         if (!get_implied_range_list(right, &right_orig))
 725                 right_orig = alloc_range_list(whole_range.min, whole_range.max);
 726
 727         left_true = clone_range_list(left_orig);
 728         left_false = clone_range_list(left_orig);
 729         right_true = clone_range_list(right_orig);
 730         right_false = clone_range_list(right_orig);
 731
 732         switch (expr->op) {
 733         case '<':
 734         case SPECIAL_UNSIGNED_LT:
 735                 if (rl_max(right_orig) != whole_range.max)
 736                         left_true = remove_range(left_orig, rl_max(right_orig), whole_range.max);
 737                 if (rl_min(right_orig) != whole_range.min)
 738                         left_false = remove_range(left_orig, whole_range.min, rl_min(right_orig) - 1);
 739
 740                 if (rl_min(left_orig) != whole_range.min)
 741                         right_true = remove_range(right_orig, whole_range.min, rl_min(left_orig));
 742                 if (rl_max(left_orig) != whole_range.max)
 743                         right_false = remove_range(right_orig, rl_max(left_orig) + 1, whole_range.max);
 744                 break;
 745         case SPECIAL_UNSIGNED_LTE:
 746         case SPECIAL_LTE:
 747                 if (rl_max(right_orig) != whole_range.max)
 748                         left_true = remove_range(left_orig, rl_max(right_orig) + 1, whole_range.max);
 749                 if (rl_min(right_orig) != whole_range.min)
 750                         left_false = remove_range(left_orig, whole_range.min, rl_min(right_orig));
 751
 752                 if (rl_min(left_orig) != whole_range.min)
 753                         right_true = remove_range(right_orig, whole_range.min, rl_min(left_orig) - 1);
 754                 if (rl_max(left_orig) != whole_range.max)
 755                         right_false = remove_range(right_orig, rl_max(left_orig), whole_range.max);
 756                 break;
 757         case SPECIAL_EQUAL:
 758                 if (rl_max(right_orig) != whole_range.max)
 759                         left_true = remove_range(left_true, rl_max(right_orig) + 1, whole_range.max);
 760                 if (rl_min(right_orig) != whole_range.min)
 761                         left_true = remove_range(left_true, whole_range.min, rl_min(right_orig) - 1);
 762                 if (rl_min(right_orig) == rl_max(right_orig))
 763                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 764
 765                 if (rl_max(left_orig) != whole_range.max)
 766                         right_true = remove_range(right_true, rl_max(left_orig) + 1, whole_range.max);
 767                 if (rl_min(left_orig) != whole_range.min)
 768                         right_true = remove_range(right_true, whole_range.min, rl_min(left_orig) - 1);
 769                 if (rl_min(left_orig) == rl_max(left_orig))
 770                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 771                 break;
 772         case SPECIAL_UNSIGNED_GTE:
 773         case SPECIAL_GTE:
 774                 if (rl_min(right_orig) != whole_range.min)
 775                         left_true = remove_range(left_orig, whole_range.min, rl_min(right_orig) - 1);
 776                 if (rl_max(right_orig) != whole_range.max)
 777                         left_false = remove_range(left_orig, rl_max(right_orig), whole_range.max);
 778
 779                 if (rl_max(left_orig) != whole_range.max)
 780                         right_true = remove_range(right_orig, rl_max(left_orig) + 1, whole_range.max);
 781                 if (rl_min(left_orig) != whole_range.min)
 782                         right_false = remove_range(right_orig, whole_range.min, rl_min(left_orig));
 783                 break;
 784         case '>':
 785         case SPECIAL_UNSIGNED_GT:
 786                 if (rl_min(right_orig) != whole_range.min)
 787                         left_true = remove_range(left_orig, whole_range.min, rl_min(right_orig));
 788                 if (rl_max(right_orig) != whole_range.max)
 789                         left_false = remove_range(left_orig, rl_max(right_orig) + 1, whole_range.max);
 790
 791                 if (rl_max(left_orig) != whole_range.max)
 792                         right_true = remove_range(right_orig, rl_max(left_orig), whole_range.max);
 793                 if (rl_min(left_orig) != whole_range.min)
 794                         right_false = remove_range(right_orig, whole_range.min, rl_min(left_orig) - 1);
 795                 break;
 796         case SPECIAL_NOTEQUAL:
 797                 if (rl_max(right_orig) != whole_range.max)
 798                         left_false = remove_range(left_false, rl_max(right_orig) + 1, whole_range.max);
 799                 if (rl_min(right_orig) != whole_range.min)
 800                         left_false = remove_range(left_false, whole_range.min, rl_min(right_orig) - 1);
 801                 if (rl_min(right_orig) == rl_max(right_orig))
 802                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 803
 804                 if (rl_max(left_orig) != whole_range.max)
 805                         right_false = remove_range(right_false, rl_max(left_orig) + 1, whole_range.max);
 806                 if (rl_min(left_orig) != whole_range.min)
 807                         right_false = remove_range(right_false, whole_range.min, rl_min(left_orig) - 1);
 808                 if (rl_min(left_orig) == rl_max(left_orig))
 809                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 810                 break;
 811         default:
 812                 return;
 813         }
 814
 815         left_true_state = alloc_extra_state_range_list(left_true);
 816         left_false_state = alloc_extra_state_range_list(left_false);
 817         right_true_state = alloc_extra_state_range_list(right_true);
 818         right_false_state = alloc_extra_state_range_list(right_false);
 819
 820         if (left_postop == SPECIAL_INCREMENT) {
 821                 left_true_state = increment_state(left_true_state);
 822                 left_false_state = increment_state(left_false_state);
 823         }
 824         if (left_postop == SPECIAL_DECREMENT) {
 825                 left_true_state = decrement_state(left_true_state);
 826                 left_false_state = decrement_state(left_false_state);
 827         }
 828         if (right_postop == SPECIAL_INCREMENT) {
 829                 right_true_state = increment_state(right_true_state);
 830                 right_false_state = increment_state(right_false_state);
 831         }
 832         if (right_postop == SPECIAL_DECREMENT) {
 833                 right_true_state = decrement_state(right_true_state);
 834                 right_false_state = decrement_state(right_false_state);
 835         }
 836
 837         set_extra_expr_true_false(left, left_true_state, left_false_state);
 838         set_extra_expr_true_false(right, right_true_state, right_false_state);
 839 }
 840
 841 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 842 void __extra_match_condition(struct expression *expr)
 843 {
 844         struct symbol *sym;
 845         char *name;
 846         struct smatch_state *pre_state;
 847         struct smatch_state *true_state;
 848         struct smatch_state *false_state;
 849
 850         expr = strip_expr(expr);
 851         switch (expr->type) {
 852         case EXPR_CALL:
 853                 function_comparison(SPECIAL_NOTEQUAL, expr, 0, 1);
 854                 return;
 855         case EXPR_PREOP:
 856         case EXPR_SYMBOL:
 857         case EXPR_DEREF:
 858                 name = get_variable_from_expr(expr, &sym);
 859                 if (!name)
 860                         return;
 861                 pre_state = get_state(my_id, name, sym);
 862                 true_state = add_filter(pre_state, 0);
 863                 if (possibly_true(SPECIAL_EQUAL, get_dinfo(pre_state), 0, 0))
 864                         false_state = alloc_extra_state(0);
 865                 else
 866                         false_state = alloc_extra_state_empty();
 867                 set_extra_true_false(name, sym, true_state, false_state);
 868                 free_string(name);
 869                 return;
 870         case EXPR_COMPARE:
 871                 match_comparison(expr);
 872                 return;
 873         case EXPR_ASSIGNMENT:
 874                 __extra_match_condition(expr->left);
 875                 return;
 876         }
 877 }
 878
 879 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 880 int implied_not_equal(struct expression *expr, long long val)
 881 {
 882         char *name;
 883         struct symbol *sym;
 884         struct smatch_state *state;
 885         long long expr_val;
 886         int ret = 0;
 887
 888         if (get_value(expr, &expr_val))
 889                 return expr_val != val;
 890
 891         name = get_variable_from_expr(expr, &sym);
 892         if (!name || !sym)
 893                 goto exit;
 894         state = get_state(my_id, name, sym);
 895         if (!state || !state->data)
 896                 goto exit;
 897         ret = !possibly_false(SPECIAL_NOTEQUAL, get_dinfo(state), val, 1);
 898 exit:
 899         free_string(name);
 900         return ret;
 901 }
 902
 903 int known_condition_true(struct expression *expr)
 904 {
 905         long long tmp;
 906         struct statement *stmt;
 907
 908         if (!expr)
 909                 return 0;
 910
 911         if (get_value(expr, &tmp) && tmp)
 912                 return 1;
 913
 914         expr = strip_expr(expr);
 915         switch (expr->type) {
 916         case EXPR_PREOP:
 917                 if (expr->op == '!') {
 918                         if (known_condition_false(expr->unop))
 919                                 return 1;
 920                         break;
 921                 }
 922                 stmt = get_expression_statement(expr);
 923                 if (last_stmt_val(stmt, &tmp) && tmp == 1)
 924                         return 1;
 925                 break;
 926         default:
 927                 break;
 928         }
 929         return 0;
 930 }
 931
 932 int known_condition_false(struct expression *expr)
 933 {
 934         long long tmp;
 935         struct statement *stmt;
 936
 937         if (!expr)
 938                 return 0;
 939
 940         if (is_zero(expr))
 941                 return 1;
 942
 943         switch (expr->type) {
 944         case EXPR_PREOP:
 945                 if (expr->op == '!') {
 946                         if (known_condition_true(expr->unop))
 947                                 return 1;
 948                         break;
 949                 }
 950                 stmt = get_expression_statement(expr);
 951                 if (last_stmt_val(stmt, &tmp) && tmp == 0)
 952                         return 1;
 953                 break;
 954         case EXPR_CALL:
 955                 if (sym_name_is("__builtin_constant_p", expr->fn))
 956                         return 1;
 957                 break;
 958         default:
 959                 break;
 960         }
 961         return 0;
 962 }
 963
 964 struct range_list *get_range_list(struct expression *expr)
 965 {
 966         long long min;
 967         long long max;
 968         struct range_list *ret = NULL;
 969         struct smatch_state *state;
 970
 971         state = get_state_expr(SMATCH_EXTRA, expr);
 972         if (state)
 973                 return clone_range_list(get_dinfo(state)->value_ranges);
 974         if (!get_absolute_min(expr, &min))
 975                 return NULL;
 976         if (!get_absolute_max(expr, &max))
 977                 return NULL;
 978         add_range(&ret, min, max);
 979         return ret;
 980 }
 981
 982 static int do_comparison(struct expression *expr)
 983 {
 984         struct range_list *left_ranges;
 985         struct range_list *right_ranges;
 986         int poss_true, poss_false;
 987
 988         left_ranges = get_range_list(expr->left);
 989         right_ranges = get_range_list(expr->right);
 990
 991         poss_true = possibly_true_range_lists(left_ranges, expr->op, right_ranges);
 992         poss_false = possibly_false_range_lists(left_ranges, expr->op, right_ranges);
 993
 994         free_range_list(&left_ranges);
 995         free_range_list(&right_ranges);
 996
 997         if (!poss_true && !poss_false)
 998                 return 0;
 999         if (poss_true && !poss_false)
1000                 return 1;
1001         if (!poss_true && poss_false)
1002                 return 2;
1003         return 3;
1004 }
1005
1006 int implied_condition_true(struct expression *expr)
1007 {
1008         struct statement *stmt;
1009         long long tmp;
1010         long long val;
1011
1012         if (!expr)
1013                 return 0;
1014
1015         if (get_implied_value(expr, &tmp) && tmp)
1016                 return 1;
1017
1018         if (expr->type == EXPR_POSTOP)
1019                 return implied_condition_true(expr->unop);
1020
1021         if (expr->type == EXPR_PREOP && expr->op == SPECIAL_DECREMENT)
1022                 return implied_not_equal(expr->unop, 1);
1023         if (expr->type == EXPR_PREOP && expr->op == SPECIAL_INCREMENT)
1024                 return implied_not_equal(expr->unop, -1);
1025
1026         expr = strip_expr(expr);
1027         switch (expr->type) {
1028         case EXPR_COMPARE:
1029                 if (do_comparison(expr) == 1)
1030                         return 1;
1031                 break;
1032         case EXPR_PREOP:
1033                 if (expr->op == '!') {
1034                         if (implied_condition_false(expr->unop))
1035                                 return 1;
1036                         break;
1037                 }
1038                 stmt = get_expression_statement(expr);
1039                 if (last_stmt_val(stmt, &val) && val == 1)
1040                         return 1;
1041                 break;
1042         default:
1043                 if (implied_not_equal(expr, 0) == 1)
1044                         return 1;
1045                 break;
1046         }
1047         return 0;
1048 }
1049
1050 int implied_condition_false(struct expression *expr)
1051 {
1052         struct statement *stmt;
1053         struct expression *tmp;
1054         long long val;
1055
1056         if (!expr)
1057                 return 0;
1058
1059         if (is_zero(expr))
1060                 return 1;
1061
1062         switch (expr->type) {
1063         case EXPR_COMPARE:
1064                 if (do_comparison(expr) == 2)
1065                         return 1;
1066         case EXPR_PREOP:
1067                 if (expr->op == '!') {
1068                         if (implied_condition_true(expr->unop))
1069                                 return 1;
1070                         break;
1071                 }
1072                 stmt = get_expression_statement(expr);
1073                 if (last_stmt_val(stmt, &val) && val == 0)
1074                         return 1;
1075                 tmp = strip_expr(expr);
1076                 if (tmp != expr)
1077                         return implied_condition_false(tmp);
1078                 break;
1079         default:
1080                 if (get_implied_value(expr, &val) && val == 0)
1081                         return 1;
1082                 break;
1083         }
1084         return 0;
1085 }
1086
1087 int get_implied_range_list(struct expression *expr, struct range_list **rl)
1088 {
1089         long long val;
1090         struct smatch_state *state;
1091         long long min;
1092         long long max;
1093
1094         expr = strip_parens(expr);
1095
1096         state = get_state_expr(my_id, expr);
1097         if (state) {
1098                 *rl = clone_range_list(get_dinfo(state)->value_ranges);
1099                 return 1;
1100         }
1101
1102         if (get_implied_value(expr, &val)) {
1103                 *rl = NULL;
1104                 add_range(rl, val, val);
1105                 return 1;
1106         }
1107
1108         if (expr->type != EXPR_BINOP)
1109                 return 0;
1110
1111         if (expr->type == EXPR_CALL) {
1112                 *rl = db_return_vals(expr);
1113                 return !!*rl;
1114         }
1115
1116         if (expr->op == '%') {
1117                 if (!get_implied_value(expr->right, &val))
1118                         return 0;
1119                 *rl = NULL;
1120                 add_range(rl, 0, val - 1);
1121                 return 1;
1122         }
1123
1124         if (!get_implied_min(expr, &min))
1125                 return 0;
1126         if (!get_implied_max(expr, &max))
1127                 return 0;
1128
1129         *rl = alloc_range_list(min, max);
1130         return 1;
1131 }
1132
1133 int is_whole_range(struct smatch_state *state)
1134 {
1135         struct data_info *dinfo;
1136         struct data_range *drange;
1137
1138         if (!state)
1139                 return 1;
1140         dinfo = get_dinfo(state);
1141         if (!dinfo || !dinfo->value_ranges)
1142                 return 1;
1143         drange = first_ptr_list((struct ptr_list *)dinfo->value_ranges);
1144         if (drange->min == whole_range.min && drange->max == whole_range.max)
1145                 return 1;
1146         return 0;
1147 }
1148
1149 static void struct_member_callback(char *fn, int param, char *printed_name, struct smatch_state *state)
1150 {
1151         if (is_whole_range(state))
1152                 return;
1153         sm_msg("info: passes param_value '%s' %d '%s' %s", fn, param, printed_name, state->name);
1154 }
1155
1156 static void match_call_info(struct expression *expr)
1157 {
1158         struct range_list *rl = NULL;
1159         struct expression *arg;
1160         char *name;
1161         int i = 0;
1162
1163         name = get_fnptr_name(expr->fn);
1164         if (!name)
1165                 return;
1166
1167         FOR_EACH_PTR(expr->args, arg) {
1168                 if (get_implied_range_list(arg, &rl) && !is_whole_range_rl(rl)) {
1169                         sm_msg("info: passes param_value '%s' %d '$$' %s",
1170                                name, i, show_ranges(rl));
1171                 }
1172                 i++;
1173         } END_FOR_EACH_PTR(arg);
1174
1175         free_string(name);
1176 }
1177
1178 void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1179 {
1180         struct range_list *rl = NULL;
1181         struct smatch_state *state;
1182         char fullname[256];
1183
1184         if (strncmp(key, "$$", 2))
1185                 return;
1186
1187         snprintf(fullname, 256, "%s%s", name, key + 2);
1188         get_value_ranges(value, &rl);
1189         char *tmp = show_ranges(rl);
1190         if (strcmp(tmp, value))
1191                 sm_msg("value = %s, ranges = %s", value, tmp);
1192         state = alloc_extra_state_range_list(rl);
1193         set_state(SMATCH_EXTRA, fullname, sym, state);
1194 }
1195
1196 static void match_call_assign(struct expression *expr)
1197 {
1198         struct expression *right;
1199         struct range_list *rl;
1200
1201         if (expr->op != '=')
1202                 return;
1203
1204         right = strip_parens(expr->right);
1205         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
1206                 right = strip_parens(right->left);
1207
1208         rl = db_return_vals(right);
1209         if (rl)
1210                 set_extra_expr_mod(expr->left, alloc_extra_state_range_list(rl));
1211         else
1212                 set_extra_expr_mod(expr->left, extra_undefined());
1213 }
1214
1215 void register_smatch_extra(int id)
1216 {
1217         my_id = id;
1218         add_merge_hook(my_id, &merge_func);
1219         add_unmatched_state_hook(my_id, &unmatched_state);
1220         add_hook(&unop_expr, OP_HOOK);
1221         add_hook(&match_function_def, FUNC_DEF_HOOK);
1222         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1223         add_hook(&match_assign, ASSIGNMENT_HOOK);
1224         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
1225         add_hook(&match_declarations, DECLARATION_HOOK);
1226         if (option_info) {
1227                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1228                 add_member_info_callback(my_id, struct_member_callback);
1229         }
1230         add_definition_db_callback(set_param_value, PARAM_VALUE);
1231 }
1232
1233 void register_smatch_extra_late(int id)
1234 {
1235         set_default_modification_hook(SMATCH_EXTRA, reset_struct_members);
1236 }