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         if (!stmt)
  37                 return 0;
  38         macro = get_macro_name(stmt->pos);
  39         if (!macro)
  40                 return 0;
  41
  42         FOR_EACH_PTR(__ignored_macros, tmp) {
  43                 if (!strcmp(tmp, macro))
  44                         return 1;
  45         } END_FOR_EACH_PTR(tmp);
  46         return 0;
  47 }
  48
  49 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
  50 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
  51 static struct void_fn_list *extra_mod_hooks;
  52 void add_extra_mod_hook(mod_hook *fn)
  53 {
  54         mod_hook **p = malloc(sizeof(mod_hook *));
  55         *p = fn;
  56         add_ptr_list(&extra_mod_hooks, p);
  57 }
  58
  59 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
  60 {
  61         mod_hook **fn;
  62
  63         FOR_EACH_PTR(extra_mod_hooks, fn) {
  64                 (*fn)(name, sym, state);
  65         } END_FOR_EACH_PTR(fn);
  66 }
  67
  68 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
  69 {
  70         if (in_warn_on_macro())
  71                 return NULL;
  72         remove_from_equiv(name, sym);
  73         call_extra_mod_hooks(name, sym, state);
  74         return set_state(SMATCH_EXTRA, name, sym, state);
  75 }
  76
  77 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
  78 {
  79         struct symbol *sym;
  80         char *name;
  81         struct sm_state *ret = NULL;
  82
  83         expr = strip_expr(expr);
  84         name = expr_to_var_sym(expr, &sym);
  85         if (!name || !sym)
  86                 goto free;
  87         ret = set_extra_mod(name, sym, state);
  88 free:
  89         free_string(name);
  90         return ret;
  91 }
  92
  93 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
  94 {
  95         struct relation *rel;
  96         struct smatch_state *orig_state;
  97
  98         orig_state = get_state(SMATCH_EXTRA, name, sym);
  99
 100         if (!estate_related(orig_state)) {
 101                 set_state(SMATCH_EXTRA, name, sym, state);
 102                 return;
 103         }
 104
 105         set_related(state, estate_related(orig_state));
 106         FOR_EACH_PTR(estate_related(orig_state), rel) {
 107                 if (option_debug_related)
 108                         sm_msg("updating related %s to %s", rel->name, state->name);
 109                 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
 110         } END_FOR_EACH_PTR(rel);
 111 }
 112
 113 /*
 114  * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
 115  */
 116 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
 117 {
 118         char *name;
 119         struct symbol *sym;
 120
 121         name = expr_to_var_sym(expr, &sym);
 122         if (!name || !sym)
 123                 goto free;
 124         set_extra_nomod(name, sym, state);
 125 free:
 126         free_string(name);
 127
 128 }
 129
 130 static void set_extra_true_false(const char *name, struct symbol *sym,
 131                         struct smatch_state *true_state,
 132                         struct smatch_state *false_state)
 133 {
 134         struct relation *rel;
 135         struct smatch_state *orig_state;
 136
 137         if (in_warn_on_macro())
 138                 return;
 139
 140         orig_state = get_state(SMATCH_EXTRA, name, sym);
 141
 142         if (!estate_related(orig_state)) {
 143                 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
 144                 return;
 145         }
 146
 147         if (true_state)
 148                 set_related(true_state, estate_related(orig_state));
 149         if (false_state)
 150                 set_related(false_state, estate_related(orig_state));
 151
 152         FOR_EACH_PTR(estate_related(orig_state), rel) {
 153                 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
 154                                 true_state, false_state);
 155         } END_FOR_EACH_PTR(rel);
 156 }
 157
 158 static void set_extra_expr_true_false(struct expression *expr,
 159                 struct smatch_state *true_state,
 160                 struct smatch_state *false_state)
 161 {
 162         char *name;
 163         struct symbol *sym;
 164
 165         expr = strip_expr(expr);
 166         name = expr_to_var_sym(expr, &sym);
 167         if (!name || !sym)
 168                 goto free;
 169         set_extra_true_false(name, sym, true_state, false_state);
 170 free:
 171         free_string(name);
 172 }
 173
 174 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 175 {
 176         struct expression *iter_var;
 177         struct expression *condition;
 178         struct sm_state *sm;
 179         struct smatch_state *estate;
 180         sval_t start;
 181
 182         condition = strip_expr(loop->iterator_pre_condition);
 183         if (!condition)
 184                 return NULL;
 185         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 186                 return NULL;
 187         if (condition->op != SPECIAL_DECREMENT)
 188                 return NULL;
 189
 190         iter_var = condition->unop;
 191         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 192         if (!sm)
 193                 return NULL;
 194         if (sval_cmp_val(estate_min(sm->state), 0) < 0)
 195                 return NULL;
 196         start = estate_max(sm->state);
 197         if  (sval_cmp_val(start, 0) <= 0)
 198                 return NULL;
 199         if (!sval_is_max(start))
 200                 start.value--;
 201
 202         if (condition->type == EXPR_PREOP) {
 203                 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
 204                 if (estate_has_hard_max(sm->state))
 205                         estate_set_hard_max(estate);
 206                 estate_copy_fuzzy_max(estate, sm->state);
 207                 set_extra_expr_mod(iter_var, estate);
 208         }
 209         if (condition->type == EXPR_POSTOP) {
 210                 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
 211                 if (estate_has_hard_max(sm->state))
 212                         estate_set_hard_max(estate);
 213                 estate_copy_fuzzy_max(estate, sm->state);
 214                 set_extra_expr_mod(iter_var, estate);
 215         }
 216         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 217 }
 218
 219 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 220                                                 struct expression *condition)
 221 {
 222         struct expression *iter_var;
 223         struct sm_state *sm;
 224         struct smatch_state *estate;
 225         sval_t start, end, max;
 226
 227         iter_var = iter_expr->unop;
 228         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 229         if (!sm)
 230                 return NULL;
 231         if (!estate_get_single_value(sm->state, &start))
 232                 return NULL;
 233         if (get_implied_max(condition->right, &end))
 234                 end = sval_cast(get_type(iter_var), end);
 235         else
 236                 end = sval_type_max(get_type(iter_var));
 237
 238         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 239                 return NULL;
 240
 241         switch (condition->op) {
 242         case SPECIAL_UNSIGNED_LT:
 243         case SPECIAL_NOTEQUAL:
 244         case '<':
 245                 if (!sval_is_min(end))
 246                         end.value--;
 247                 break;
 248         case SPECIAL_UNSIGNED_LTE:
 249         case SPECIAL_LTE:
 250                 break;
 251         default:
 252                 return NULL;
 253         }
 254         if (sval_cmp(end, start) < 0)
 255                 return NULL;
 256         estate = alloc_estate_range(start, end);
 257         if (get_hard_max(condition->right, &max)) {
 258                 estate_set_hard_max(estate);
 259                 if (condition->op == '<' ||
 260                     condition->op == SPECIAL_UNSIGNED_LT ||
 261                     condition->op == SPECIAL_NOTEQUAL)
 262                         max.value--;
 263                 estate_set_fuzzy_max(estate, max);
 264         }
 265         set_extra_expr_mod(iter_var, estate);
 266         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 267 }
 268
 269 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 270                                                 struct expression *condition)
 271 {
 272         struct expression *iter_var;
 273         struct sm_state *sm;
 274         struct smatch_state *estate;
 275         sval_t start, end;
 276
 277         iter_var = iter_expr->unop;
 278         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 279         if (!sm)
 280                 return NULL;
 281         if (!estate_get_single_value(sm->state, &start))
 282                 return NULL;
 283         if (!get_implied_min(condition->right, &end))
 284                 end = sval_type_min(get_type(iter_var));
 285         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 286                 return NULL;
 287
 288         switch (condition->op) {
 289         case SPECIAL_NOTEQUAL:
 290         case '>':
 291                 if (!sval_is_min(end) && !sval_is_max(end))
 292                         end.value++;
 293                 break;
 294         case SPECIAL_GTE:
 295                 break;
 296         default:
 297                 return NULL;
 298         }
 299         if (sval_cmp(end, start) > 0)
 300                 return NULL;
 301         estate = alloc_estate_range(end, start);
 302         estate_set_hard_max(estate);
 303         estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
 304         set_extra_expr_mod(iter_var, estate);
 305         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 306 }
 307
 308 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 309 {
 310         struct expression *iter_expr;
 311         struct expression *condition;
 312
 313         if (!loop->iterator_post_statement)
 314                 return NULL;
 315         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 316                 return NULL;
 317         iter_expr = loop->iterator_post_statement->expression;
 318         if (!loop->iterator_pre_condition)
 319                 return NULL;
 320         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 321                 return NULL;
 322         condition = loop->iterator_pre_condition;
 323
 324         if (iter_expr->op == SPECIAL_INCREMENT)
 325                 return handle_canonical_for_inc(iter_expr, condition);
 326         if (iter_expr->op == SPECIAL_DECREMENT)
 327                 return handle_canonical_for_dec(iter_expr, condition);
 328         return NULL;
 329 }
 330
 331 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 332 {
 333         struct sm_state *ret;
 334
 335         __push_fake_cur_slist();
 336         if (!loop->iterator_post_statement)
 337                 ret = handle_canonical_while_count_down(loop);
 338         else
 339                 ret = handle_canonical_for_loops(loop);
 340         *slist = __pop_fake_cur_slist();
 341         return ret;
 342 }
 343
 344 int __iterator_unchanged(struct sm_state *sm)
 345 {
 346         if (!sm)
 347                 return 0;
 348         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 349                 return 1;
 350         return 0;
 351 }
 352
 353 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 354 {
 355         sval_t after_value;
 356
 357         /* paranoid checking.  prolly not needed */
 358         condition = strip_expr(condition);
 359         if (!condition)
 360                 return;
 361         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 362                 return;
 363         if (condition->op != SPECIAL_DECREMENT)
 364                 return;
 365         after_value = estate_min(sm->state);
 366         after_value.value--;
 367         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
 368 }
 369
 370 void __extra_pre_loop_hook_after(struct sm_state *sm,
 371                                 struct statement *iterator,
 372                                 struct expression *condition)
 373 {
 374         struct expression *iter_expr;
 375         sval_t limit;
 376         struct smatch_state *state;
 377
 378         if (!iterator) {
 379                 while_count_down_after(sm, condition);
 380                 return;
 381         }
 382
 383         iter_expr = iterator->expression;
 384
 385         if (condition->type != EXPR_COMPARE)
 386                 return;
 387         if (iter_expr->op == SPECIAL_INCREMENT) {
 388                 limit = sval_binop(estate_max(sm->state), '+',
 389                                    sval_type_val(estate_type(sm->state), 1));
 390         } else {
 391                 limit = sval_binop(estate_min(sm->state), '-',
 392                                    sval_type_val(estate_type(sm->state), 1));
 393         }
 394         if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
 395                 if (iter_expr->op == SPECIAL_INCREMENT)
 396                         state = alloc_estate_range(estate_min(sm->state), limit);
 397                 else
 398                         state = alloc_estate_range(limit, estate_max(sm->state));
 399         } else {
 400                 state = alloc_estate_sval(limit);
 401         }
 402         if (!estate_has_hard_max(sm->state)) {
 403                 estate_clear_hard_max(state);
 404         }
 405         if (estate_has_fuzzy_max(sm->state)) {
 406                 sval_t hmax = estate_get_fuzzy_max(sm->state);
 407                 sval_t max = estate_max(sm->state);
 408
 409                 if (sval_cmp(hmax, max) != 0)
 410                         estate_clear_fuzzy_max(state);
 411         } else if (!estate_has_fuzzy_max(sm->state)) {
 412                 estate_clear_fuzzy_max(state);
 413         }
 414
 415         set_extra_mod(sm->name, sm->sym, state);
 416 }
 417
 418 static struct state_list *unmatched_slist;
 419 static struct smatch_state *unmatched_state(struct sm_state *sm)
 420 {
 421         struct smatch_state *state;
 422
 423         if (unmatched_slist) {
 424                 state = get_state_slist(unmatched_slist, SMATCH_EXTRA, sm->name, sm->sym);
 425                 if (state)
 426                         return state;
 427         }
 428         return alloc_estate_whole(estate_type(sm->state));
 429 }
 430
 431 static void clear_the_pointed_at(struct expression *expr, struct state_list *slist)
 432 {
 433         char *name;
 434         struct symbol *sym;
 435         struct sm_state *tmp;
 436
 437         name = expr_to_var_sym(expr, &sym);
 438         if (!name || !sym)
 439                 goto free;
 440
 441         FOR_EACH_PTR(slist, tmp) {
 442                 if (tmp->name[0] != '*')
 443                         continue;
 444                 if (tmp->sym != sym)
 445                         continue;
 446                 if (strcmp(tmp->name + 1, name) != 0)
 447                         continue;
 448                 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
 449         } END_FOR_EACH_PTR(tmp);
 450
 451 free:
 452         free_string(name);
 453 }
 454
 455 static void match_function_call(struct expression *expr)
 456 {
 457         struct expression *arg;
 458         struct expression *tmp;
 459         struct state_list *slist;
 460
 461         /* if we have the db this is handled in smatch_function_hooks.c */
 462         if (!option_no_db)
 463                 return;
 464         if (inlinable(expr->fn))
 465                 return;
 466
 467         slist = get_all_states(SMATCH_EXTRA);
 468
 469         FOR_EACH_PTR(expr->args, arg) {
 470                 tmp = strip_expr(arg);
 471                 if (tmp->type == EXPR_PREOP && tmp->op == '&')
 472                         set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
 473                 else
 474                         clear_the_pointed_at(tmp, slist);
 475         } END_FOR_EACH_PTR(arg);
 476
 477         free_slist(&slist);
 478 }
 479
 480 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 481 {
 482         if (!one || !two)
 483                 return 0;
 484         if (one->type == SYM_PTR && two->type == SYM_PTR)
 485                 return 1;
 486         return types_equiv(one, two);
 487 }
 488
 489 static void match_vanilla_assign(struct expression *left, struct expression *right)
 490 {
 491         struct range_list *rl = NULL;
 492         struct symbol *right_sym;
 493         struct symbol *left_type;
 494         struct symbol *right_type;
 495         char *right_name = NULL;
 496         struct symbol *sym;
 497         char *name;
 498         sval_t max;
 499         struct smatch_state *state;
 500
 501         name = expr_to_var_sym(left, &sym);
 502         if (!name)
 503                 return;
 504
 505         left_type = get_type(left);
 506         right_type = get_type(right);
 507
 508         right_name = expr_to_var_sym(right, &right_sym);
 509         if (right_name && right_sym &&
 510             types_equiv_or_pointer(left_type, right_type)) {
 511                 set_equiv(left, right);
 512                 goto free;
 513         }
 514
 515         if (get_implied_rl(right, &rl)) {
 516                 rl = cast_rl(left_type, rl);
 517                 state = alloc_estate_rl(rl);
 518                 if (get_hard_max(right, &max)) {
 519                         estate_set_hard_max(state);
 520                         estate_set_fuzzy_max(state, max);
 521                 }
 522         } else {
 523                 rl = alloc_whole_rl(right_type);
 524                 rl = cast_rl(left_type, rl);
 525                 state = alloc_estate_rl(rl);
 526         }
 527         set_extra_mod(name, sym, state);
 528 free:
 529         free_string(right_name);
 530 }
 531
 532 static int op_remove_assign(int op)
 533 {
 534         switch (op) {
 535         case SPECIAL_ADD_ASSIGN:
 536                 return '+';
 537         case SPECIAL_SUB_ASSIGN:
 538                 return '-';
 539         case SPECIAL_MUL_ASSIGN:
 540                 return '*';
 541         case SPECIAL_DIV_ASSIGN:
 542                 return '/';
 543         case SPECIAL_MOD_ASSIGN:
 544                 return '%';
 545         case SPECIAL_AND_ASSIGN:
 546                 return '&';
 547         case SPECIAL_OR_ASSIGN:
 548                 return '|';
 549         case SPECIAL_XOR_ASSIGN:
 550                 return '^';
 551         case SPECIAL_SHL_ASSIGN:
 552                 return SPECIAL_LEFTSHIFT;
 553         case SPECIAL_SHR_ASSIGN:
 554                 return SPECIAL_RIGHTSHIFT;
 555         default:
 556                 return op;
 557         }
 558 }
 559
 560 static void match_assign(struct expression *expr)
 561 {
 562         struct range_list *rl = NULL;
 563         struct expression *left;
 564         struct expression *right;
 565         struct expression *binop_expr;
 566         struct symbol *left_type;
 567         struct symbol *right_type;
 568         struct symbol *sym;
 569         char *name;
 570         sval_t left_min, left_max;
 571         sval_t right_min, right_max;
 572         sval_t res_min, res_max;
 573
 574         left = strip_expr(expr->left);
 575
 576         right = strip_expr(expr->right);
 577         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 578                 right = strip_expr(right->left);
 579
 580         if (is_condition(expr->right))
 581                 return; /* handled in smatch_condition.c */
 582         if (expr->op == '=' && right->type == EXPR_CALL)
 583                 return; /* handled in smatch_function_hooks.c */
 584         if (expr->op == '=') {
 585                 match_vanilla_assign(left, right);
 586                 return;
 587         }
 588
 589         name = expr_to_var_sym(left, &sym);
 590         if (!name)
 591                 return;
 592
 593         left_type = get_type(left);
 594         right_type = get_type(right);
 595
 596         res_min = sval_type_min(right_type);
 597         res_max = sval_type_max(right_type);
 598
 599         switch (expr->op) {
 600         case SPECIAL_ADD_ASSIGN:
 601                 get_absolute_max(left, &left_max);
 602                 get_absolute_max(right, &right_max);
 603                 if (sval_binop_overflows(left_max, '+', right_max))
 604                         break;
 605                 if (get_implied_min(left, &left_min) &&
 606                     !sval_is_negative_min(left_min) &&
 607                     get_implied_min(right, &right_min) &&
 608                     !sval_is_negative_min(right_min)) {
 609                         res_min = sval_binop(left_min, '+', right_min);
 610                         res_min = sval_cast(right_type, res_min);
 611                 }
 612                 if (inside_loop())  /* we are assuming loops don't lead to wrapping */
 613                         break;
 614                 res_max = sval_binop(left_max, '+', right_max);
 615                 res_max = sval_cast(right_type, res_max);
 616                 break;
 617         case SPECIAL_SUB_ASSIGN:
 618                 if (get_implied_max(left, &left_max) &&
 619                     !sval_is_max(left_max) &&
 620                     get_implied_min(right, &right_min) &&
 621                     !sval_is_min(right_min)) {
 622                         res_max = sval_binop(left_max, '-', right_min);
 623                         res_max = sval_cast(right_type, res_max);
 624                 }
 625                 if (inside_loop())
 626                         break;
 627                 if (get_implied_min(left, &left_min) &&
 628                     !sval_is_min(left_min) &&
 629                     get_implied_max(right, &right_max) &&
 630                     !sval_is_max(right_max)) {
 631                         res_min = sval_binop(left_min, '-', right_max);
 632                         res_min = sval_cast(right_type, res_min);
 633                 }
 634                 break;
 635         case SPECIAL_AND_ASSIGN:
 636         case SPECIAL_MOD_ASSIGN:
 637                 binop_expr = binop_expression(expr->left,
 638                                               op_remove_assign(expr->op),
 639                                               expr->right);
 640                 if (get_implied_rl(binop_expr, &rl)) {
 641                         rl = cast_rl(left_type, rl);
 642                         set_extra_mod(name, sym, alloc_estate_rl(rl));
 643                         goto free;
 644                 }
 645         }
 646         rl = cast_rl(left_type, alloc_rl(res_min, res_max));
 647         set_extra_mod(name, sym, alloc_estate_rl(rl));
 648 free:
 649         free_string(name);
 650 }
 651
 652 static struct smatch_state *increment_state(struct smatch_state *state)
 653 {
 654         sval_t min = estate_min(state);
 655         sval_t max = estate_max(state);
 656
 657         if (!estate_rl(state))
 658                 return NULL;
 659
 660         if (inside_loop())
 661                 max = sval_type_max(max.type);
 662
 663         if (!sval_is_min(min) && !sval_is_max(min))
 664                 min.value++;
 665         if (!sval_is_min(max) && !sval_is_max(max))
 666                 max.value++;
 667         return alloc_estate_range(min, max);
 668 }
 669
 670 static struct smatch_state *decrement_state(struct smatch_state *state)
 671 {
 672         sval_t min = estate_min(state);
 673         sval_t max = estate_max(state);
 674
 675         if (!estate_rl(state))
 676                 return NULL;
 677
 678         if (inside_loop())
 679                 min = sval_type_min(min.type);
 680
 681         if (!sval_is_min(min) && !sval_is_max(min))
 682                 min.value--;
 683         if (!sval_is_min(max) && !sval_is_max(max))
 684                 max.value--;
 685         return alloc_estate_range(min, max);
 686 }
 687
 688 static void unop_expr(struct expression *expr)
 689 {
 690         struct smatch_state *state;
 691
 692         if (expr->smatch_flags & Handled)
 693                 return;
 694
 695         switch (expr->op) {
 696         case SPECIAL_INCREMENT:
 697                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 698                 state = increment_state(state);
 699                 if (!state)
 700                         state = alloc_estate_whole(get_type(expr));
 701                 set_extra_expr_mod(expr->unop, state);
 702                 break;
 703         case SPECIAL_DECREMENT:
 704                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 705                 state = decrement_state(state);
 706                 if (!state)
 707                         state = alloc_estate_whole(get_type(expr));
 708                 set_extra_expr_mod(expr->unop, state);
 709                 break;
 710         default:
 711                 return;
 712         }
 713 }
 714
 715 static void asm_expr(struct statement *stmt)
 716 {
 717
 718         struct expression *expr;
 719         struct symbol *type;
 720         int state = 0;
 721
 722         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 723                 switch (state) {
 724                 case 0: /* identifier */
 725                 case 1: /* constraint */
 726                         state++;
 727                         continue;
 728                 case 2: /* expression */
 729                         state = 0;
 730                         type = get_type(strip_expr(expr));
 731                         set_extra_expr_mod(expr, alloc_estate_whole(type));
 732                         continue;
 733                 }
 734         } END_FOR_EACH_PTR(expr);
 735 }
 736
 737 static void delete_state_tracker(struct tracker *t)
 738 {
 739         remove_from_equiv(t->name, t->sym);
 740         delete_state(t->owner, t->name, t->sym);
 741 }
 742
 743 static void scoped_state_extra(const char *name, struct symbol *sym)
 744 {
 745         struct tracker *t;
 746
 747         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 748         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 749 }
 750
 751 static void match_declarations(struct symbol *sym)
 752 {
 753         const char *name;
 754
 755         if (sym->ident) {
 756                 name = sym->ident->name;
 757                 if (!sym->initializer) {
 758                         set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
 759                         scoped_state_extra(name, sym);
 760                 }
 761         }
 762 }
 763
 764 static void check_dereference(struct expression *expr)
 765 {
 766         if (outside_of_function())
 767                 return;
 768         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 769 }
 770
 771 static void match_dereferences(struct expression *expr)
 772 {
 773         if (expr->type != EXPR_PREOP)
 774                 return;
 775         check_dereference(expr->unop);
 776 }
 777
 778 static void match_pointer_as_array(struct expression *expr)
 779 {
 780         if (!is_array(expr))
 781                 return;
 782         check_dereference(expr->unop->left);
 783 }
 784
 785 static void set_param_dereferenced(struct expression *arg, char *unused)
 786 {
 787         check_dereference(arg);
 788 }
 789
 790 static void match_function_def(struct symbol *sym)
 791 {
 792         struct symbol *arg;
 793
 794         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 795                 if (!arg->ident)
 796                         continue;
 797                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 798         } END_FOR_EACH_PTR(arg);
 799 }
 800
 801 static sval_t add_one(sval_t sval)
 802 {
 803         sval.value++;
 804         return sval;
 805 }
 806
 807 static sval_t sub_one(sval_t sval)
 808 {
 809         sval.value--;
 810         return sval;
 811 }
 812
 813 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
 814 {
 815         struct range_list *left_orig;
 816         struct range_list *left_true;
 817         struct range_list *left_false;
 818         struct range_list *right_orig;
 819         struct range_list *right_true;
 820         struct range_list *right_false;
 821         struct smatch_state *left_true_state;
 822         struct smatch_state *left_false_state;
 823         struct smatch_state *right_true_state;
 824         struct smatch_state *right_false_state;
 825         sval_t min, max, dummy, hard_max;
 826         int left_postop = 0;
 827         int right_postop = 0;
 828
 829         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 830                 if (left->type == EXPR_POSTOP) {
 831                         left->smatch_flags |= Handled;
 832                         left_postop = left->op;
 833                 }
 834                 left = strip_expr(left->unop);
 835         }
 836         while (left->type == EXPR_ASSIGNMENT)
 837                 left = strip_expr(left->left);
 838
 839         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 840                 if (right->type == EXPR_POSTOP) {
 841                         right->smatch_flags |= Handled;
 842                         right_postop = right->op;
 843                 }
 844                 right = strip_expr(right->unop);
 845         }
 846
 847         if (get_implied_rl(left, &left_orig)) {
 848                 left_orig = cast_rl(type, left_orig);
 849         } else {
 850                 min = sval_type_min(get_type(left));
 851                 max = sval_type_max(get_type(left));
 852                 left_orig = cast_rl(type, alloc_rl(min, max));
 853         }
 854
 855         if (get_implied_rl(right, &right_orig)) {
 856                 right_orig = cast_rl(type, right_orig);
 857         } else {
 858                 min = sval_type_min(get_type(right));
 859                 max = sval_type_max(get_type(right));
 860                 right_orig = cast_rl(type, alloc_rl(min, max));
 861         }
 862         min = sval_type_min(type);
 863         max = sval_type_max(type);
 864
 865         left_true = clone_rl(left_orig);
 866         left_false = clone_rl(left_orig);
 867         right_true = clone_rl(right_orig);
 868         right_false = clone_rl(right_orig);
 869
 870         switch (op) {
 871         case '<':
 872         case SPECIAL_UNSIGNED_LT:
 873                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 874                 if (!sval_is_min(rl_min(right_orig))) {
 875                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 876                 }
 877
 878                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 879                 if (!sval_is_max(rl_max(left_orig)))
 880                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 881                 break;
 882         case SPECIAL_UNSIGNED_LTE:
 883         case SPECIAL_LTE:
 884                 if (!sval_is_max(rl_max(right_orig)))
 885                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 886                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 887
 888                 if (!sval_is_min(rl_min(left_orig)))
 889                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 890                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 891
 892                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 893                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 894                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 895                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 896                 break;
 897         case SPECIAL_EQUAL:
 898                 if (!sval_is_max(rl_max(right_orig))) {
 899                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 900                 }
 901                 if (!sval_is_min(rl_min(right_orig))) {
 902                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 903                 }
 904                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 905                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 906
 907                 if (!sval_is_max(rl_max(left_orig)))
 908                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 909                 if (!sval_is_min(rl_min(left_orig)))
 910                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 911                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 912                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 913                 break;
 914         case SPECIAL_UNSIGNED_GTE:
 915         case SPECIAL_GTE:
 916                 if (!sval_is_min(rl_min(right_orig)))
 917                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 918                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 919
 920                 if (!sval_is_max(rl_max(left_orig)))
 921                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 922                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 923
 924                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 925                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 926                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 927                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 928                 break;
 929         case '>':
 930         case SPECIAL_UNSIGNED_GT:
 931                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 932                 if (!sval_is_max(rl_max(right_orig)))
 933                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 934
 935                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 936                 if (!sval_is_min(rl_min(left_orig)))
 937                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 938                 break;
 939         case SPECIAL_NOTEQUAL:
 940                 if (!sval_is_max(rl_max(right_orig)))
 941                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 942                 if (!sval_is_min(rl_min(right_orig)))
 943                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 944                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 945                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 946
 947                 if (!sval_is_max(rl_max(left_orig)))
 948                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 949                 if (!sval_is_min(rl_min(left_orig)))
 950                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 951                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 952                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 953                 break;
 954         default:
 955                 return;
 956         }
 957
 958         left_true = rl_truncate_cast(get_type(left), left_true);
 959         left_false = rl_truncate_cast(get_type(left), left_false);
 960         right_true = rl_truncate_cast(get_type(right), right_true);
 961         right_false = rl_truncate_cast(get_type(right), right_false);
 962
 963         left_true_state = alloc_estate_rl(left_true);
 964         left_false_state = alloc_estate_rl(left_false);
 965         right_true_state = alloc_estate_rl(right_true);
 966         right_false_state = alloc_estate_rl(right_false);
 967
 968         switch (op) {
 969         case '<':
 970         case SPECIAL_UNSIGNED_LT:
 971         case SPECIAL_UNSIGNED_LTE:
 972         case SPECIAL_LTE:
 973                 if (get_hard_max(right, &dummy))
 974                         estate_set_hard_max(left_true_state);
 975                 if (get_hard_max(left, &dummy))
 976                         estate_set_hard_max(right_false_state);
 977                 break;
 978         case '>':
 979         case SPECIAL_UNSIGNED_GT:
 980         case SPECIAL_UNSIGNED_GTE:
 981         case SPECIAL_GTE:
 982                 if (get_hard_max(left, &dummy))
 983                         estate_set_hard_max(right_true_state);
 984                 if (get_hard_max(right, &dummy))
 985                         estate_set_hard_max(left_false_state);
 986                 break;
 987         }
 988
 989         switch (op) {
 990         case '<':
 991         case SPECIAL_UNSIGNED_LT:
 992         case SPECIAL_UNSIGNED_LTE:
 993         case SPECIAL_LTE:
 994                 if (get_hard_max(right, &hard_max)) {
 995                         if (op == '<' || op == SPECIAL_UNSIGNED_LT)
 996                                 hard_max.value--;
 997                         estate_set_fuzzy_max(left_true_state, hard_max);
 998                 }
 999                 if (get_implied_value(right, &hard_max)) {
1000                         if (op == SPECIAL_UNSIGNED_LTE ||
1001                             op == SPECIAL_LTE)
1002                                 hard_max.value++;
1003                         estate_set_fuzzy_max(left_false_state, hard_max);
1004                 }
1005                 if (get_hard_max(left, &hard_max)) {
1006                         if (op == SPECIAL_UNSIGNED_LTE ||
1007                             op == SPECIAL_LTE)
1008                                 hard_max.value--;
1009                         estate_set_fuzzy_max(right_false_state, hard_max);
1010                 }
1011                 if (get_implied_value(left, &hard_max)) {
1012                         if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1013                                 hard_max.value++;
1014                         estate_set_fuzzy_max(right_true_state, hard_max);
1015                 }
1016                 break;
1017         case '>':
1018         case SPECIAL_UNSIGNED_GT:
1019         case SPECIAL_UNSIGNED_GTE:
1020         case SPECIAL_GTE:
1021                 if (get_hard_max(left, &hard_max)) {
1022                         if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1023                                 hard_max.value--;
1024                         estate_set_fuzzy_max(right_true_state, hard_max);
1025                 }
1026                 if (get_implied_value(left, &hard_max)) {
1027                         if (op == SPECIAL_UNSIGNED_GTE ||
1028                             op == SPECIAL_GTE)
1029                                 hard_max.value++;
1030                         estate_set_fuzzy_max(right_false_state, hard_max);
1031                 }
1032                 if (get_hard_max(right, &hard_max)) {
1033                         if (op == SPECIAL_UNSIGNED_LTE ||
1034                             op == SPECIAL_LTE)
1035                                 hard_max.value--;
1036                         estate_set_fuzzy_max(left_false_state, hard_max);
1037                 }
1038                 if (get_implied_value(right, &hard_max)) {
1039                         if (op == '>' ||
1040                             op == SPECIAL_UNSIGNED_GT)
1041                                 hard_max.value++;
1042                         estate_set_fuzzy_max(left_true_state, hard_max);
1043                 }
1044                 break;
1045         case SPECIAL_EQUAL:
1046                 if (get_hard_max(left, &hard_max))
1047                         estate_set_fuzzy_max(right_true_state, hard_max);
1048                 if (get_hard_max(right, &hard_max))
1049                         estate_set_fuzzy_max(left_true_state, hard_max);
1050                 break;
1051         }
1052
1053         if (get_hard_max(left, &hard_max)) {
1054                 estate_set_hard_max(left_true_state);
1055                 estate_set_hard_max(left_false_state);
1056         }
1057         if (get_hard_max(right, &hard_max)) {
1058                 estate_set_hard_max(right_true_state);
1059                 estate_set_hard_max(right_false_state);
1060         }
1061
1062         if (left_postop == SPECIAL_INCREMENT) {
1063                 left_true_state = increment_state(left_true_state);
1064                 left_false_state = increment_state(left_false_state);
1065         }
1066         if (left_postop == SPECIAL_DECREMENT) {
1067                 left_true_state = decrement_state(left_true_state);
1068                 left_false_state = decrement_state(left_false_state);
1069         }
1070         if (right_postop == SPECIAL_INCREMENT) {
1071                 right_true_state = increment_state(right_true_state);
1072                 right_false_state = increment_state(right_false_state);
1073         }
1074         if (right_postop == SPECIAL_DECREMENT) {
1075                 right_true_state = decrement_state(right_true_state);
1076                 right_false_state = decrement_state(right_false_state);
1077         }
1078
1079         set_extra_expr_true_false(left, left_true_state, left_false_state);
1080         set_extra_expr_true_false(right, right_true_state, right_false_state);
1081 }
1082
1083 static int opposite_op(int op)
1084 {
1085         switch (op) {
1086         case '+':
1087                 return '-';
1088         case '-':
1089                 return '+';
1090         }
1091         return 0;
1092 }
1093
1094 static int is_simple_math(struct expression *expr)
1095 {
1096         if (!expr)
1097                 return 0;
1098         if (expr->type != EXPR_BINOP)
1099                 return 0;
1100         if (!opposite_op(expr->op))
1101                 return 0;
1102         return 1;
1103 }
1104
1105 static void move_known_values(struct expression **left_p, struct expression **right_p)
1106 {
1107         struct expression *left = *left_p;
1108         struct expression *right = *right_p;
1109         sval_t sval;
1110
1111         if (get_implied_value(left, &sval)) {
1112                 if (!is_simple_math(right))
1113                         return;
1114                 if (right->op == '+' && get_value(right->left, &sval)) {
1115                         *left_p = binop_expression(left, opposite_op(right->op), right->left);
1116                         *right_p = right->right;
1117                         return;
1118                 }
1119                 if (get_value(right->right, &sval)) {
1120                         *left_p = binop_expression(left, opposite_op(right->op), right->right);
1121                         *right_p = right->left;
1122                         return;
1123                 }
1124                 return;
1125         }
1126         if (get_implied_value(right, &sval)) {
1127                 if (!is_simple_math(left))
1128                         return;
1129                 if (left->op == '+' && get_value(left->left, &sval)) {
1130                         *right_p = binop_expression(right, opposite_op(left->op), left->left);
1131                         *left_p = left->right;
1132                         return;
1133                 }
1134
1135                 if (get_value(left->right, &sval)) {
1136                         *right_p = binop_expression(right, opposite_op(left->op), left->right);
1137                         *left_p = left->left;
1138                         return;
1139                 }
1140                 return;
1141         }
1142 }
1143
1144 static int match_func_comparison(struct expression *expr)
1145 {
1146         struct expression *left = strip_expr(expr->left);
1147         struct expression *right = strip_expr(expr->right);
1148         sval_t sval;
1149
1150         /*
1151          * fixme: think about this harder. We should always be trying to limit
1152          * the non-call side as well.  If we can't determine the limitter does
1153          * that mean we aren't querying the database and are missing important
1154          * information?
1155          */
1156
1157         if (left->type == EXPR_CALL) {
1158                 if (get_implied_value(left, &sval)) {
1159                         handle_comparison(get_type(expr), left, expr->op, right);
1160                         return 1;
1161                 }
1162                 if (!get_implied_value(right, &sval))
1163                         return 1;
1164                 function_comparison(expr->op, left, sval, 1);
1165                 return 1;
1166         }
1167
1168         if (right->type == EXPR_CALL) {
1169                 if (get_implied_value(right, &sval)) {
1170                         handle_comparison(get_type(expr), left, expr->op, right);
1171                         return 1;
1172                 }
1173                 if (!get_implied_value(left, &sval))
1174                         return 1;
1175                 function_comparison(expr->op, right, sval, 0);
1176                 return 1;
1177         }
1178
1179         return 0;
1180 }
1181
1182 static void match_comparison(struct expression *expr)
1183 {
1184         struct expression *left_orig = strip_expr(expr->left);
1185         struct expression *right_orig = strip_expr(expr->right);
1186         struct expression *left, *right;
1187         struct expression *prev;
1188         struct symbol *type;
1189
1190         if (match_func_comparison(expr))
1191                 return;
1192
1193         type = get_type(expr);
1194         if (!type)
1195                 type = &llong_ctype;
1196
1197         left = left_orig;
1198         right = right_orig;
1199         move_known_values(&left, &right);
1200         handle_comparison(type, left, expr->op, right);
1201
1202         prev = get_assigned_expr(left_orig);
1203         if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1204                 left = prev;
1205                 right = right_orig;
1206                 move_known_values(&left, &right);
1207                 handle_comparison(type, left, expr->op, right);
1208         }
1209
1210         prev = get_assigned_expr(right_orig);
1211         if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1212                 left = left_orig;
1213                 right = prev;
1214                 move_known_values(&left, &right);
1215                 handle_comparison(type, left, expr->op, right);
1216         }
1217 }
1218
1219 static void handle_AND_condition(struct expression *expr)
1220 {
1221         struct range_list *rl = NULL;
1222         sval_t known;
1223
1224         if (get_implied_value(expr->left, &known) && known.value > 0) {
1225                 known.value--;
1226                 get_absolute_rl(expr->right, &rl);
1227                 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1228                 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1229                 return;
1230         }
1231
1232         if (get_implied_value(expr->right, &known) && known.value > 0) {
1233                 known.value--;
1234                 get_absolute_rl(expr->left, &rl);
1235                 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1236                 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1237                 return;
1238         }
1239 }
1240
1241 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
1242 void __extra_match_condition(struct expression *expr)
1243 {
1244         struct symbol *sym;
1245         char *name;
1246         struct smatch_state *pre_state;
1247         struct smatch_state *true_state;
1248         struct smatch_state *false_state;
1249
1250         expr = strip_expr(expr);
1251         switch (expr->type) {
1252         case EXPR_CALL:
1253                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
1254                 return;
1255         case EXPR_PREOP:
1256         case EXPR_SYMBOL:
1257         case EXPR_DEREF: {
1258                 sval_t zero;
1259
1260                 zero = sval_blank(expr);
1261                 zero.value = 0;
1262
1263                 name = expr_to_var_sym(expr, &sym);
1264                 if (!name)
1265                         return;
1266                 pre_state = get_state(my_id, name, sym);
1267                 true_state = estate_filter_sval(pre_state, zero);
1268                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1269                         false_state = alloc_estate_sval(zero);
1270                 else
1271                         false_state = alloc_estate_empty();
1272                 set_extra_true_false(name, sym, true_state, false_state);
1273                 free_string(name);
1274                 return;
1275         }
1276         case EXPR_COMPARE:
1277                 match_comparison(expr);
1278                 return;
1279         case EXPR_ASSIGNMENT:
1280                 __extra_match_condition(expr->left);
1281                 return;
1282         case EXPR_BINOP:
1283                 if (expr->op == '&')
1284                         handle_AND_condition(expr);
1285                 return;
1286         }
1287 }
1288
1289 static void assume_indexes_are_valid(struct expression *expr)
1290 {
1291         struct expression *array_expr;
1292         int array_size;
1293         struct expression *offset;
1294         struct symbol *offset_type;
1295         struct range_list *rl_before;
1296         struct range_list *rl_after;
1297         struct range_list *filter = NULL;
1298         sval_t size;
1299
1300         expr = strip_expr(expr);
1301         if (!is_array(expr))
1302                 return;
1303
1304         offset = get_array_offset(expr);
1305         offset_type = get_type(offset);
1306         if (offset_type && type_signed(offset_type)) {
1307                 filter = alloc_rl(sval_type_min(offset_type),
1308                                   sval_type_val(offset_type, -1));
1309         }
1310
1311         array_expr = strip_parens(expr->unop->left);
1312         array_size = get_real_array_size(array_expr);
1313         if (array_size > 1) {
1314                 size = sval_type_val(offset_type, array_size);
1315                 add_range(&filter, size, sval_type_max(offset_type));
1316         }
1317
1318         if (!filter)
1319                 return;
1320         get_absolute_rl(offset, &rl_before);
1321         rl_after = rl_filter(rl_before, filter);
1322         if (rl_equiv(rl_before, rl_after))
1323                 return;
1324         set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1325 }
1326
1327 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1328 int implied_not_equal(struct expression *expr, long long val)
1329 {
1330         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1331 }
1332
1333 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1334 {
1335         if (estate_is_whole(state))
1336                 return;
1337         sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1338         if (estate_has_fuzzy_max(state))
1339                 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1340                                        sval_to_str(estate_get_fuzzy_max(state)));
1341 }
1342
1343 static void db_limited_before(void)
1344 {
1345         unmatched_slist = clone_slist(__get_cur_slist());
1346 }
1347
1348 static void db_limited_after(void)
1349 {
1350         free_slist(&unmatched_slist);
1351 }
1352
1353 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, int mod)
1354 {
1355         struct expression *arg;
1356         char *name;
1357         struct symbol *sym;
1358         struct sm_state *sm;
1359         struct symbol *type;
1360         struct range_list *rl;
1361         struct range_list *limit;
1362         struct range_list *new;
1363
1364         while (expr->type == EXPR_ASSIGNMENT)
1365                 expr = strip_expr(expr->right);
1366         if (expr->type != EXPR_CALL)
1367                 return;
1368
1369         arg = get_argument_from_call_expr(expr->args, param);
1370         if (!arg)
1371                 return;
1372
1373         name = get_variable_from_key(arg, key, &sym);
1374         if (!name || !sym)
1375                 goto free;
1376
1377         sm = get_sm_state(SMATCH_EXTRA, name, sym);
1378         type = get_member_type_from_key(arg, key);
1379         if (sm)
1380                 rl = estate_rl(sm->state);
1381         else
1382                 rl = alloc_whole_rl(type);
1383
1384         call_results_to_rl(expr, type, value, &limit);
1385         new = rl_intersection(rl, limit);
1386
1387         /* We want to preserve the implications here */
1388         if (sm && rl_equiv(estate_rl(sm->state), new)) {
1389                 __set_sm(sm);
1390         } else {
1391                 if (mod)
1392                         set_extra_mod(name, sym, alloc_estate_rl(new));
1393                 else
1394                         set_extra_nomod(name, sym, alloc_estate_rl(new));
1395         }
1396
1397 free:
1398         free_string(name);
1399 }
1400
1401 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1402 {
1403         db_param_limit_filter(expr, param, key, value, 0);
1404 }
1405
1406 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1407 {
1408         db_param_limit_filter(expr, param, key, value, 1);
1409 }
1410
1411 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1412 {
1413         struct expression *arg;
1414         char *name;
1415         struct symbol *sym;
1416         struct symbol *type;
1417         struct smatch_state *state;
1418         struct range_list *added = NULL;
1419         struct range_list *new;
1420
1421         while (expr->type == EXPR_ASSIGNMENT)
1422                 expr = strip_expr(expr->right);
1423         if (expr->type != EXPR_CALL)
1424                 return;
1425
1426         arg = get_argument_from_call_expr(expr->args, param);
1427         if (!arg)
1428                 return;
1429         name = get_variable_from_key(arg, key, &sym);
1430         if (!name || !sym)
1431                 goto free;
1432
1433         type = get_member_type_from_key(arg, key);
1434         state = get_state(SMATCH_EXTRA, name, sym);
1435         if (state) {
1436                 call_results_to_rl(expr, type, value, &added);
1437                 new = rl_union(estate_rl(state), added);
1438         } else {
1439                 new = alloc_whole_rl(type);
1440         }
1441
1442         set_extra_mod(name, sym, alloc_estate_rl(new));
1443 free:
1444         free_string(name);
1445 }
1446
1447 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1448 {
1449         struct symbol *type;
1450         struct symbol *sym;
1451         char *name;
1452         struct range_list *rl;
1453
1454         if (expr->type != EXPR_ASSIGNMENT)
1455                 return;
1456
1457         name = return_state_to_var_sym(expr, param, key, &sym);
1458         if (!name || !sym)
1459                 goto free;
1460         type = get_member_type_from_key(expr->left, key);
1461         if (!type)
1462                 return;
1463         call_results_to_rl(expr->right, type, value, &rl);
1464         set_extra_mod(name, sym, alloc_estate_rl(rl));
1465
1466 free:
1467         free_string(name);
1468 }
1469
1470 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1471 {
1472         if (estate_is_whole(state))
1473                 return;
1474
1475         /* these are handled in smatch_param_filter/set/limit.c */
1476         if (printed_name[0] != '*' &&
1477             !strchr(printed_name, '.') && !strchr(printed_name, '-'))
1478                 return;
1479
1480         sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1481                         printed_name, state->name);
1482 }
1483
1484 static void match_call_info(struct expression *expr)
1485 {
1486         struct smatch_state *state;
1487         struct range_list *rl = NULL;
1488         struct expression *arg;
1489         struct symbol *type;
1490         int i = 0;
1491
1492         FOR_EACH_PTR(expr->args, arg) {
1493                 type = get_arg_type(expr->fn, i);
1494
1495                 if (get_implied_rl(arg, &rl))
1496                         rl = cast_rl(type, rl);
1497                 else
1498                         rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1499
1500                 sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1501                 state = get_state_expr(SMATCH_EXTRA, arg);
1502                 if (estate_has_fuzzy_max(state)) {
1503                         sql_insert_caller_info(expr, FUZZY_MAX, i, "$$",
1504                                                sval_to_str(estate_get_fuzzy_max(state)));
1505                 }
1506                 i++;
1507         } END_FOR_EACH_PTR(arg);
1508 }
1509
1510 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1511 {
1512         struct range_list *rl = NULL;
1513         struct smatch_state *state;
1514         struct symbol *type;
1515         char fullname[256];
1516
1517         if (strcmp(key, "*$$") == 0)
1518                 snprintf(fullname, sizeof(fullname), "*%s", name);
1519         else if (strncmp(key, "$$", 2) == 0)
1520                 snprintf(fullname, 256, "%s%s", name, key + 2);
1521         else
1522                 return;
1523
1524         type = get_member_type_from_key(symbol_expression(sym), key);
1525         str_to_rl(type, value, &rl);
1526         state = alloc_estate_rl(rl);
1527         set_state(SMATCH_EXTRA, fullname, sym, state);
1528 }
1529
1530 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
1531 {
1532         struct range_list *rl = NULL;
1533         struct smatch_state *state;
1534         struct symbol *type;
1535         char fullname[256];
1536         sval_t max;
1537
1538         if (strcmp(key, "*$$") == 0)
1539                 snprintf(fullname, sizeof(fullname), "*%s", name);
1540         else if (strncmp(key, "$$", 2) == 0)
1541                 snprintf(fullname, 256, "%s%s", name, key + 2);
1542         else
1543                 return;
1544
1545         state = get_state(SMATCH_EXTRA, fullname, sym);
1546         if (!state)
1547                 return;
1548         type = get_member_type_from_key(symbol_expression(sym), key);
1549         str_to_rl(type, value, &rl);
1550         if (!rl_to_sval(rl, &max))
1551                 return;
1552         estate_set_fuzzy_max(state, max);
1553 }
1554
1555 void register_smatch_extra(int id)
1556 {
1557         my_id = id;
1558
1559         add_merge_hook(my_id, &merge_estates);
1560         add_unmatched_state_hook(my_id, &unmatched_state);
1561         add_hook(&match_function_def, FUNC_DEF_HOOK);
1562         add_hook(&match_declarations, DECLARATION_HOOK);
1563         select_caller_info_hook(set_param_value, PARAM_VALUE);
1564         select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
1565         select_return_states_hook(RETURN_VALUE, &db_returned_member_info);
1566         select_return_states_before(&db_limited_before);
1567         select_return_states_hook(LIMITED_VALUE, &db_param_limit);
1568         select_return_states_hook(FILTER_VALUE, &db_param_filter);
1569         select_return_states_hook(ADDED_VALUE, &db_param_add);
1570         select_return_states_after(&db_limited_after);
1571 }
1572
1573 void register_smatch_extra_late(int id)
1574 {
1575         add_hook(&match_dereferences, DEREF_HOOK);
1576         add_hook(&match_pointer_as_array, OP_HOOK);
1577         select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
1578         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1579         add_hook(&match_assign, ASSIGNMENT_HOOK);
1580         add_hook(&unop_expr, OP_HOOK);
1581         add_hook(&asm_expr, ASM_HOOK);
1582
1583         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1584         add_member_info_callback(my_id, struct_member_callback);
1585         add_returned_member_callback(my_id, returned_member_callback);
1586
1587         add_hook(&assume_indexes_are_valid, OP_HOOK);
1588 }