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         case SPECIAL_SHL_ASSIGN:
 638         case SPECIAL_SHR_ASSIGN:
 639         case SPECIAL_OR_ASSIGN:
 640         case SPECIAL_XOR_ASSIGN:
 641         case SPECIAL_MUL_ASSIGN:
 642         case SPECIAL_DIV_ASSIGN:
 643                 binop_expr = binop_expression(expr->left,
 644                                               op_remove_assign(expr->op),
 645                                               expr->right);
 646                 if (get_implied_rl(binop_expr, &rl)) {
 647                         rl = cast_rl(left_type, rl);
 648                         set_extra_mod(name, sym, alloc_estate_rl(rl));
 649                         goto free;
 650                 }
 651                 break;
 652         }
 653         rl = cast_rl(left_type, alloc_rl(res_min, res_max));
 654         set_extra_mod(name, sym, alloc_estate_rl(rl));
 655 free:
 656         free_string(name);
 657 }
 658
 659 static struct smatch_state *increment_state(struct smatch_state *state)
 660 {
 661         sval_t min = estate_min(state);
 662         sval_t max = estate_max(state);
 663
 664         if (!estate_rl(state))
 665                 return NULL;
 666
 667         if (inside_loop())
 668                 max = sval_type_max(max.type);
 669
 670         if (!sval_is_min(min) && !sval_is_max(min))
 671                 min.value++;
 672         if (!sval_is_min(max) && !sval_is_max(max))
 673                 max.value++;
 674         return alloc_estate_range(min, max);
 675 }
 676
 677 static struct smatch_state *decrement_state(struct smatch_state *state)
 678 {
 679         sval_t min = estate_min(state);
 680         sval_t max = estate_max(state);
 681
 682         if (!estate_rl(state))
 683                 return NULL;
 684
 685         if (inside_loop())
 686                 min = sval_type_min(min.type);
 687
 688         if (!sval_is_min(min) && !sval_is_max(min))
 689                 min.value--;
 690         if (!sval_is_min(max) && !sval_is_max(max))
 691                 max.value--;
 692         return alloc_estate_range(min, max);
 693 }
 694
 695 static void unop_expr(struct expression *expr)
 696 {
 697         struct smatch_state *state;
 698
 699         if (expr->smatch_flags & Handled)
 700                 return;
 701
 702         switch (expr->op) {
 703         case SPECIAL_INCREMENT:
 704                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 705                 state = increment_state(state);
 706                 if (!state)
 707                         state = alloc_estate_whole(get_type(expr));
 708                 set_extra_expr_mod(expr->unop, state);
 709                 break;
 710         case SPECIAL_DECREMENT:
 711                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 712                 state = decrement_state(state);
 713                 if (!state)
 714                         state = alloc_estate_whole(get_type(expr));
 715                 set_extra_expr_mod(expr->unop, state);
 716                 break;
 717         default:
 718                 return;
 719         }
 720 }
 721
 722 static void asm_expr(struct statement *stmt)
 723 {
 724
 725         struct expression *expr;
 726         struct symbol *type;
 727         int state = 0;
 728
 729         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 730                 switch (state) {
 731                 case 0: /* identifier */
 732                 case 1: /* constraint */
 733                         state++;
 734                         continue;
 735                 case 2: /* expression */
 736                         state = 0;
 737                         type = get_type(strip_expr(expr));
 738                         set_extra_expr_mod(expr, alloc_estate_whole(type));
 739                         continue;
 740                 }
 741         } END_FOR_EACH_PTR(expr);
 742 }
 743
 744 static void delete_state_tracker(struct tracker *t)
 745 {
 746         remove_from_equiv(t->name, t->sym);
 747         delete_state(t->owner, t->name, t->sym);
 748 }
 749
 750 static void scoped_state_extra(const char *name, struct symbol *sym)
 751 {
 752         struct tracker *t;
 753
 754         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 755         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 756 }
 757
 758 static void match_declarations(struct symbol *sym)
 759 {
 760         const char *name;
 761
 762         if (sym->ident) {
 763                 name = sym->ident->name;
 764                 if (!sym->initializer) {
 765                         set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
 766                         scoped_state_extra(name, sym);
 767                 }
 768         }
 769 }
 770
 771 static void check_dereference(struct expression *expr)
 772 {
 773         if (outside_of_function())
 774                 return;
 775         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 776 }
 777
 778 static void match_dereferences(struct expression *expr)
 779 {
 780         if (expr->type != EXPR_PREOP)
 781                 return;
 782         check_dereference(expr->unop);
 783 }
 784
 785 static void match_pointer_as_array(struct expression *expr)
 786 {
 787         if (!is_array(expr))
 788                 return;
 789         check_dereference(expr->unop->left);
 790 }
 791
 792 static void set_param_dereferenced(struct expression *arg, char *unused)
 793 {
 794         check_dereference(arg);
 795 }
 796
 797 static void match_function_def(struct symbol *sym)
 798 {
 799         struct symbol *arg;
 800
 801         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 802                 if (!arg->ident)
 803                         continue;
 804                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 805         } END_FOR_EACH_PTR(arg);
 806 }
 807
 808 static sval_t add_one(sval_t sval)
 809 {
 810         sval.value++;
 811         return sval;
 812 }
 813
 814 static sval_t sub_one(sval_t sval)
 815 {
 816         sval.value--;
 817         return sval;
 818 }
 819
 820 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
 821 {
 822         struct range_list *left_orig;
 823         struct range_list *left_true;
 824         struct range_list *left_false;
 825         struct range_list *right_orig;
 826         struct range_list *right_true;
 827         struct range_list *right_false;
 828         struct smatch_state *left_true_state;
 829         struct smatch_state *left_false_state;
 830         struct smatch_state *right_true_state;
 831         struct smatch_state *right_false_state;
 832         sval_t min, max, dummy, hard_max;
 833         int left_postop = 0;
 834         int right_postop = 0;
 835
 836         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 837                 if (left->type == EXPR_POSTOP) {
 838                         left->smatch_flags |= Handled;
 839                         left_postop = left->op;
 840                 }
 841                 left = strip_expr(left->unop);
 842         }
 843         while (left->type == EXPR_ASSIGNMENT)
 844                 left = strip_expr(left->left);
 845
 846         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 847                 if (right->type == EXPR_POSTOP) {
 848                         right->smatch_flags |= Handled;
 849                         right_postop = right->op;
 850                 }
 851                 right = strip_expr(right->unop);
 852         }
 853
 854         if (get_implied_rl(left, &left_orig)) {
 855                 left_orig = cast_rl(type, left_orig);
 856         } else {
 857                 min = sval_type_min(get_type(left));
 858                 max = sval_type_max(get_type(left));
 859                 left_orig = cast_rl(type, alloc_rl(min, max));
 860         }
 861
 862         if (get_implied_rl(right, &right_orig)) {
 863                 right_orig = cast_rl(type, right_orig);
 864         } else {
 865                 min = sval_type_min(get_type(right));
 866                 max = sval_type_max(get_type(right));
 867                 right_orig = cast_rl(type, alloc_rl(min, max));
 868         }
 869         min = sval_type_min(type);
 870         max = sval_type_max(type);
 871
 872         left_true = clone_rl(left_orig);
 873         left_false = clone_rl(left_orig);
 874         right_true = clone_rl(right_orig);
 875         right_false = clone_rl(right_orig);
 876
 877         switch (op) {
 878         case '<':
 879         case SPECIAL_UNSIGNED_LT:
 880                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 881                 if (!sval_is_min(rl_min(right_orig))) {
 882                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 883                 }
 884
 885                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 886                 if (!sval_is_max(rl_max(left_orig)))
 887                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 888                 break;
 889         case SPECIAL_UNSIGNED_LTE:
 890         case SPECIAL_LTE:
 891                 if (!sval_is_max(rl_max(right_orig)))
 892                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 893                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 894
 895                 if (!sval_is_min(rl_min(left_orig)))
 896                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 897                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 898
 899                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 900                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 901                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 902                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 903                 break;
 904         case SPECIAL_EQUAL:
 905                 if (!sval_is_max(rl_max(right_orig))) {
 906                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 907                 }
 908                 if (!sval_is_min(rl_min(right_orig))) {
 909                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 910                 }
 911                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 912                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 913
 914                 if (!sval_is_max(rl_max(left_orig)))
 915                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 916                 if (!sval_is_min(rl_min(left_orig)))
 917                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 918                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 919                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 920                 break;
 921         case SPECIAL_UNSIGNED_GTE:
 922         case SPECIAL_GTE:
 923                 if (!sval_is_min(rl_min(right_orig)))
 924                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 925                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 926
 927                 if (!sval_is_max(rl_max(left_orig)))
 928                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 929                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 930
 931                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 932                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 933                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 934                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 935                 break;
 936         case '>':
 937         case SPECIAL_UNSIGNED_GT:
 938                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 939                 if (!sval_is_max(rl_max(right_orig)))
 940                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 941
 942                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 943                 if (!sval_is_min(rl_min(left_orig)))
 944                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 945                 break;
 946         case SPECIAL_NOTEQUAL:
 947                 if (!sval_is_max(rl_max(right_orig)))
 948                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 949                 if (!sval_is_min(rl_min(right_orig)))
 950                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 951                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 952                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 953
 954                 if (!sval_is_max(rl_max(left_orig)))
 955                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 956                 if (!sval_is_min(rl_min(left_orig)))
 957                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 958                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 959                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 960                 break;
 961         default:
 962                 return;
 963         }
 964
 965         left_true = rl_truncate_cast(get_type(left), left_true);
 966         left_false = rl_truncate_cast(get_type(left), left_false);
 967         right_true = rl_truncate_cast(get_type(right), right_true);
 968         right_false = rl_truncate_cast(get_type(right), right_false);
 969
 970         left_true_state = alloc_estate_rl(left_true);
 971         left_false_state = alloc_estate_rl(left_false);
 972         right_true_state = alloc_estate_rl(right_true);
 973         right_false_state = alloc_estate_rl(right_false);
 974
 975         switch (op) {
 976         case '<':
 977         case SPECIAL_UNSIGNED_LT:
 978         case SPECIAL_UNSIGNED_LTE:
 979         case SPECIAL_LTE:
 980                 if (get_hard_max(right, &dummy))
 981                         estate_set_hard_max(left_true_state);
 982                 if (get_hard_max(left, &dummy))
 983                         estate_set_hard_max(right_false_state);
 984                 break;
 985         case '>':
 986         case SPECIAL_UNSIGNED_GT:
 987         case SPECIAL_UNSIGNED_GTE:
 988         case SPECIAL_GTE:
 989                 if (get_hard_max(left, &dummy))
 990                         estate_set_hard_max(right_true_state);
 991                 if (get_hard_max(right, &dummy))
 992                         estate_set_hard_max(left_false_state);
 993                 break;
 994         }
 995
 996         switch (op) {
 997         case '<':
 998         case SPECIAL_UNSIGNED_LT:
 999         case SPECIAL_UNSIGNED_LTE:
1000         case SPECIAL_LTE:
1001                 if (get_hard_max(right, &hard_max)) {
1002                         if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1003                                 hard_max.value--;
1004                         estate_set_fuzzy_max(left_true_state, hard_max);
1005                 }
1006                 if (get_implied_value(right, &hard_max)) {
1007                         if (op == SPECIAL_UNSIGNED_LTE ||
1008                             op == SPECIAL_LTE)
1009                                 hard_max.value++;
1010                         estate_set_fuzzy_max(left_false_state, hard_max);
1011                 }
1012                 if (get_hard_max(left, &hard_max)) {
1013                         if (op == SPECIAL_UNSIGNED_LTE ||
1014                             op == SPECIAL_LTE)
1015                                 hard_max.value--;
1016                         estate_set_fuzzy_max(right_false_state, hard_max);
1017                 }
1018                 if (get_implied_value(left, &hard_max)) {
1019                         if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1020                                 hard_max.value++;
1021                         estate_set_fuzzy_max(right_true_state, hard_max);
1022                 }
1023                 break;
1024         case '>':
1025         case SPECIAL_UNSIGNED_GT:
1026         case SPECIAL_UNSIGNED_GTE:
1027         case SPECIAL_GTE:
1028                 if (get_hard_max(left, &hard_max)) {
1029                         if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1030                                 hard_max.value--;
1031                         estate_set_fuzzy_max(right_true_state, hard_max);
1032                 }
1033                 if (get_implied_value(left, &hard_max)) {
1034                         if (op == SPECIAL_UNSIGNED_GTE ||
1035                             op == SPECIAL_GTE)
1036                                 hard_max.value++;
1037                         estate_set_fuzzy_max(right_false_state, hard_max);
1038                 }
1039                 if (get_hard_max(right, &hard_max)) {
1040                         if (op == SPECIAL_UNSIGNED_LTE ||
1041                             op == SPECIAL_LTE)
1042                                 hard_max.value--;
1043                         estate_set_fuzzy_max(left_false_state, hard_max);
1044                 }
1045                 if (get_implied_value(right, &hard_max)) {
1046                         if (op == '>' ||
1047                             op == SPECIAL_UNSIGNED_GT)
1048                                 hard_max.value++;
1049                         estate_set_fuzzy_max(left_true_state, hard_max);
1050                 }
1051                 break;
1052         case SPECIAL_EQUAL:
1053                 if (get_hard_max(left, &hard_max))
1054                         estate_set_fuzzy_max(right_true_state, hard_max);
1055                 if (get_hard_max(right, &hard_max))
1056                         estate_set_fuzzy_max(left_true_state, hard_max);
1057                 break;
1058         }
1059
1060         if (get_hard_max(left, &hard_max)) {
1061                 estate_set_hard_max(left_true_state);
1062                 estate_set_hard_max(left_false_state);
1063         }
1064         if (get_hard_max(right, &hard_max)) {
1065                 estate_set_hard_max(right_true_state);
1066                 estate_set_hard_max(right_false_state);
1067         }
1068
1069         if (left_postop == SPECIAL_INCREMENT) {
1070                 left_true_state = increment_state(left_true_state);
1071                 left_false_state = increment_state(left_false_state);
1072         }
1073         if (left_postop == SPECIAL_DECREMENT) {
1074                 left_true_state = decrement_state(left_true_state);
1075                 left_false_state = decrement_state(left_false_state);
1076         }
1077         if (right_postop == SPECIAL_INCREMENT) {
1078                 right_true_state = increment_state(right_true_state);
1079                 right_false_state = increment_state(right_false_state);
1080         }
1081         if (right_postop == SPECIAL_DECREMENT) {
1082                 right_true_state = decrement_state(right_true_state);
1083                 right_false_state = decrement_state(right_false_state);
1084         }
1085
1086         set_extra_expr_true_false(left, left_true_state, left_false_state);
1087         set_extra_expr_true_false(right, right_true_state, right_false_state);
1088 }
1089
1090 static int opposite_op(int op)
1091 {
1092         switch (op) {
1093         case '+':
1094                 return '-';
1095         case '-':
1096                 return '+';
1097         }
1098         return 0;
1099 }
1100
1101 static int is_simple_math(struct expression *expr)
1102 {
1103         if (!expr)
1104                 return 0;
1105         if (expr->type != EXPR_BINOP)
1106                 return 0;
1107         if (!opposite_op(expr->op))
1108                 return 0;
1109         return 1;
1110 }
1111
1112 static void move_known_values(struct expression **left_p, struct expression **right_p)
1113 {
1114         struct expression *left = *left_p;
1115         struct expression *right = *right_p;
1116         sval_t sval;
1117
1118         if (get_implied_value(left, &sval)) {
1119                 if (!is_simple_math(right))
1120                         return;
1121                 if (right->op == '+' && get_value(right->left, &sval)) {
1122                         *left_p = binop_expression(left, opposite_op(right->op), right->left);
1123                         *right_p = right->right;
1124                         return;
1125                 }
1126                 if (get_value(right->right, &sval)) {
1127                         *left_p = binop_expression(left, opposite_op(right->op), right->right);
1128                         *right_p = right->left;
1129                         return;
1130                 }
1131                 return;
1132         }
1133         if (get_implied_value(right, &sval)) {
1134                 if (!is_simple_math(left))
1135                         return;
1136                 if (left->op == '+' && get_value(left->left, &sval)) {
1137                         *right_p = binop_expression(right, opposite_op(left->op), left->left);
1138                         *left_p = left->right;
1139                         return;
1140                 }
1141
1142                 if (get_value(left->right, &sval)) {
1143                         *right_p = binop_expression(right, opposite_op(left->op), left->right);
1144                         *left_p = left->left;
1145                         return;
1146                 }
1147                 return;
1148         }
1149 }
1150
1151 static int match_func_comparison(struct expression *expr)
1152 {
1153         struct expression *left = strip_expr(expr->left);
1154         struct expression *right = strip_expr(expr->right);
1155         sval_t sval;
1156
1157         /*
1158          * fixme: think about this harder. We should always be trying to limit
1159          * the non-call side as well.  If we can't determine the limitter does
1160          * that mean we aren't querying the database and are missing important
1161          * information?
1162          */
1163
1164         if (left->type == EXPR_CALL) {
1165                 if (get_implied_value(left, &sval)) {
1166                         handle_comparison(get_type(expr), left, expr->op, right);
1167                         return 1;
1168                 }
1169                 if (!get_implied_value(right, &sval))
1170                         return 1;
1171                 function_comparison(expr->op, left, sval, 1);
1172                 return 1;
1173         }
1174
1175         if (right->type == EXPR_CALL) {
1176                 if (get_implied_value(right, &sval)) {
1177                         handle_comparison(get_type(expr), left, expr->op, right);
1178                         return 1;
1179                 }
1180                 if (!get_implied_value(left, &sval))
1181                         return 1;
1182                 function_comparison(expr->op, right, sval, 0);
1183                 return 1;
1184         }
1185
1186         return 0;
1187 }
1188
1189 static void match_comparison(struct expression *expr)
1190 {
1191         struct expression *left_orig = strip_expr(expr->left);
1192         struct expression *right_orig = strip_expr(expr->right);
1193         struct expression *left, *right;
1194         struct expression *prev;
1195         struct symbol *type;
1196
1197         if (match_func_comparison(expr))
1198                 return;
1199
1200         type = get_type(expr);
1201         if (!type)
1202                 type = &llong_ctype;
1203
1204         left = left_orig;
1205         right = right_orig;
1206         move_known_values(&left, &right);
1207         handle_comparison(type, left, expr->op, right);
1208
1209         prev = get_assigned_expr(left_orig);
1210         if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1211                 left = prev;
1212                 right = right_orig;
1213                 move_known_values(&left, &right);
1214                 handle_comparison(type, left, expr->op, right);
1215         }
1216
1217         prev = get_assigned_expr(right_orig);
1218         if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1219                 left = left_orig;
1220                 right = prev;
1221                 move_known_values(&left, &right);
1222                 handle_comparison(type, left, expr->op, right);
1223         }
1224 }
1225
1226 static void handle_AND_condition(struct expression *expr)
1227 {
1228         struct range_list *rl = NULL;
1229         sval_t known;
1230
1231         if (get_implied_value(expr->left, &known) && known.value > 0) {
1232                 known.value--;
1233                 get_absolute_rl(expr->right, &rl);
1234                 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1235                 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1236                 return;
1237         }
1238
1239         if (get_implied_value(expr->right, &known) && known.value > 0) {
1240                 known.value--;
1241                 get_absolute_rl(expr->left, &rl);
1242                 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1243                 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1244                 return;
1245         }
1246 }
1247
1248 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
1249 void __extra_match_condition(struct expression *expr)
1250 {
1251         struct symbol *sym;
1252         char *name;
1253         struct smatch_state *pre_state;
1254         struct smatch_state *true_state;
1255         struct smatch_state *false_state;
1256
1257         expr = strip_expr(expr);
1258         switch (expr->type) {
1259         case EXPR_CALL:
1260                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
1261                 return;
1262         case EXPR_PREOP:
1263         case EXPR_SYMBOL:
1264         case EXPR_DEREF: {
1265                 sval_t zero;
1266
1267                 zero = sval_blank(expr);
1268                 zero.value = 0;
1269
1270                 name = expr_to_var_sym(expr, &sym);
1271                 if (!name)
1272                         return;
1273                 pre_state = get_state(my_id, name, sym);
1274                 true_state = estate_filter_sval(pre_state, zero);
1275                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1276                         false_state = alloc_estate_sval(zero);
1277                 else
1278                         false_state = alloc_estate_empty();
1279                 set_extra_true_false(name, sym, true_state, false_state);
1280                 free_string(name);
1281                 return;
1282         }
1283         case EXPR_COMPARE:
1284                 match_comparison(expr);
1285                 return;
1286         case EXPR_ASSIGNMENT:
1287                 __extra_match_condition(expr->left);
1288                 return;
1289         case EXPR_BINOP:
1290                 if (expr->op == '&')
1291                         handle_AND_condition(expr);
1292                 return;
1293         }
1294 }
1295
1296 static void assume_indexes_are_valid(struct expression *expr)
1297 {
1298         struct expression *array_expr;
1299         int array_size;
1300         struct expression *offset;
1301         struct symbol *offset_type;
1302         struct range_list *rl_before;
1303         struct range_list *rl_after;
1304         struct range_list *filter = NULL;
1305         sval_t size;
1306
1307         expr = strip_expr(expr);
1308         if (!is_array(expr))
1309                 return;
1310
1311         offset = get_array_offset(expr);
1312         offset_type = get_type(offset);
1313         if (offset_type && type_signed(offset_type)) {
1314                 filter = alloc_rl(sval_type_min(offset_type),
1315                                   sval_type_val(offset_type, -1));
1316         }
1317
1318         array_expr = strip_parens(expr->unop->left);
1319         array_size = get_real_array_size(array_expr);
1320         if (array_size > 1) {
1321                 size = sval_type_val(offset_type, array_size);
1322                 add_range(&filter, size, sval_type_max(offset_type));
1323         }
1324
1325         if (!filter)
1326                 return;
1327         get_absolute_rl(offset, &rl_before);
1328         rl_after = rl_filter(rl_before, filter);
1329         if (rl_equiv(rl_before, rl_after))
1330                 return;
1331         set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1332 }
1333
1334 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1335 int implied_not_equal(struct expression *expr, long long val)
1336 {
1337         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1338 }
1339
1340 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1341 {
1342         if (estate_is_whole(state))
1343                 return;
1344         sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1345         if (estate_has_fuzzy_max(state))
1346                 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1347                                        sval_to_str(estate_get_fuzzy_max(state)));
1348 }
1349
1350 static void db_limited_before(void)
1351 {
1352         unmatched_slist = clone_slist(__get_cur_slist());
1353 }
1354
1355 static void db_limited_after(void)
1356 {
1357         free_slist(&unmatched_slist);
1358 }
1359
1360 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, int mod)
1361 {
1362         struct expression *arg;
1363         char *name;
1364         struct symbol *sym;
1365         struct sm_state *sm;
1366         struct symbol *type;
1367         struct range_list *rl;
1368         struct range_list *limit;
1369         struct range_list *new;
1370
1371         while (expr->type == EXPR_ASSIGNMENT)
1372                 expr = strip_expr(expr->right);
1373         if (expr->type != EXPR_CALL)
1374                 return;
1375
1376         arg = get_argument_from_call_expr(expr->args, param);
1377         if (!arg)
1378                 return;
1379
1380         name = get_variable_from_key(arg, key, &sym);
1381         if (!name || !sym)
1382                 goto free;
1383
1384         sm = get_sm_state(SMATCH_EXTRA, name, sym);
1385         type = get_member_type_from_key(arg, key);
1386         if (sm)
1387                 rl = estate_rl(sm->state);
1388         else
1389                 rl = alloc_whole_rl(type);
1390
1391         call_results_to_rl(expr, type, value, &limit);
1392         new = rl_intersection(rl, limit);
1393
1394         /* We want to preserve the implications here */
1395         if (sm && rl_equiv(estate_rl(sm->state), new)) {
1396                 __set_sm(sm);
1397         } else {
1398                 if (mod)
1399                         set_extra_mod(name, sym, alloc_estate_rl(new));
1400                 else
1401                         set_extra_nomod(name, sym, alloc_estate_rl(new));
1402         }
1403
1404 free:
1405         free_string(name);
1406 }
1407
1408 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1409 {
1410         db_param_limit_filter(expr, param, key, value, 0);
1411 }
1412
1413 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1414 {
1415         db_param_limit_filter(expr, param, key, value, 1);
1416 }
1417
1418 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1419 {
1420         struct expression *arg;
1421         char *name;
1422         struct symbol *sym;
1423         struct symbol *type;
1424         struct smatch_state *state;
1425         struct range_list *added = NULL;
1426         struct range_list *new;
1427
1428         while (expr->type == EXPR_ASSIGNMENT)
1429                 expr = strip_expr(expr->right);
1430         if (expr->type != EXPR_CALL)
1431                 return;
1432
1433         arg = get_argument_from_call_expr(expr->args, param);
1434         if (!arg)
1435                 return;
1436         name = get_variable_from_key(arg, key, &sym);
1437         if (!name || !sym)
1438                 goto free;
1439
1440         type = get_member_type_from_key(arg, key);
1441         state = get_state(SMATCH_EXTRA, name, sym);
1442         if (state) {
1443                 call_results_to_rl(expr, type, value, &added);
1444                 new = rl_union(estate_rl(state), added);
1445         } else {
1446                 new = alloc_whole_rl(type);
1447         }
1448
1449         set_extra_mod(name, sym, alloc_estate_rl(new));
1450 free:
1451         free_string(name);
1452 }
1453
1454 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1455 {
1456         struct symbol *type;
1457         struct symbol *sym;
1458         char *name;
1459         struct range_list *rl;
1460
1461         if (expr->type != EXPR_ASSIGNMENT)
1462                 return;
1463
1464         name = return_state_to_var_sym(expr, param, key, &sym);
1465         if (!name || !sym)
1466                 goto free;
1467         type = get_member_type_from_key(expr->left, key);
1468         if (!type)
1469                 return;
1470         call_results_to_rl(expr->right, type, value, &rl);
1471         set_extra_mod(name, sym, alloc_estate_rl(rl));
1472
1473 free:
1474         free_string(name);
1475 }
1476
1477 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1478 {
1479         if (estate_is_whole(state))
1480                 return;
1481
1482         /* these are handled in smatch_param_filter/set/limit.c */
1483         if (printed_name[0] != '*' &&
1484             !strchr(printed_name, '.') && !strchr(printed_name, '-'))
1485                 return;
1486
1487         sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1488                         printed_name, state->name);
1489 }
1490
1491 static void match_call_info(struct expression *expr)
1492 {
1493         struct smatch_state *state;
1494         struct range_list *rl = NULL;
1495         struct expression *arg;
1496         struct symbol *type;
1497         int i = 0;
1498
1499         FOR_EACH_PTR(expr->args, arg) {
1500                 type = get_arg_type(expr->fn, i);
1501
1502                 if (get_implied_rl(arg, &rl))
1503                         rl = cast_rl(type, rl);
1504                 else
1505                         rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1506
1507                 if (!is_whole_rl(rl))
1508                         sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1509                 state = get_state_expr(SMATCH_EXTRA, arg);
1510                 if (estate_has_fuzzy_max(state)) {
1511                         sql_insert_caller_info(expr, FUZZY_MAX, i, "$$",
1512                                                sval_to_str(estate_get_fuzzy_max(state)));
1513                 }
1514                 i++;
1515         } END_FOR_EACH_PTR(arg);
1516 }
1517
1518 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1519 {
1520         struct range_list *rl = NULL;
1521         struct smatch_state *state;
1522         struct symbol *type;
1523         char fullname[256];
1524
1525         if (strcmp(key, "*$$") == 0)
1526                 snprintf(fullname, sizeof(fullname), "*%s", name);
1527         else if (strncmp(key, "$$", 2) == 0)
1528                 snprintf(fullname, 256, "%s%s", name, key + 2);
1529         else
1530                 return;
1531
1532         type = get_member_type_from_key(symbol_expression(sym), key);
1533         str_to_rl(type, value, &rl);
1534         state = alloc_estate_rl(rl);
1535         set_state(SMATCH_EXTRA, fullname, sym, state);
1536 }
1537
1538 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
1539 {
1540         struct range_list *rl = NULL;
1541         struct smatch_state *state;
1542         struct symbol *type;
1543         char fullname[256];
1544         sval_t max;
1545
1546         if (strcmp(key, "*$$") == 0)
1547                 snprintf(fullname, sizeof(fullname), "*%s", name);
1548         else if (strncmp(key, "$$", 2) == 0)
1549                 snprintf(fullname, 256, "%s%s", name, key + 2);
1550         else
1551                 return;
1552
1553         state = get_state(SMATCH_EXTRA, fullname, sym);
1554         if (!state)
1555                 return;
1556         type = get_member_type_from_key(symbol_expression(sym), key);
1557         str_to_rl(type, value, &rl);
1558         if (!rl_to_sval(rl, &max))
1559                 return;
1560         estate_set_fuzzy_max(state, max);
1561 }
1562
1563 void register_smatch_extra(int id)
1564 {
1565         my_id = id;
1566
1567         add_merge_hook(my_id, &merge_estates);
1568         add_unmatched_state_hook(my_id, &unmatched_state);
1569         add_hook(&match_function_def, FUNC_DEF_HOOK);
1570         add_hook(&match_declarations, DECLARATION_HOOK);
1571         select_caller_info_hook(set_param_value, PARAM_VALUE);
1572         select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
1573         select_return_states_hook(RETURN_VALUE, &db_returned_member_info);
1574         select_return_states_before(&db_limited_before);
1575         select_return_states_hook(LIMITED_VALUE, &db_param_limit);
1576         select_return_states_hook(FILTER_VALUE, &db_param_filter);
1577         select_return_states_hook(ADDED_VALUE, &db_param_add);
1578         select_return_states_after(&db_limited_after);
1579 }
1580
1581 void register_smatch_extra_late(int id)
1582 {
1583         add_hook(&match_dereferences, DEREF_HOOK);
1584         add_hook(&match_pointer_as_array, OP_HOOK);
1585         select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
1586         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1587         add_hook(&match_assign, ASSIGNMENT_HOOK);
1588         add_hook(&unop_expr, OP_HOOK);
1589         add_hook(&asm_expr, ASM_HOOK);
1590
1591         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1592         add_member_info_callback(my_id, struct_member_callback);
1593         add_returned_member_callback(my_id, returned_member_callback);
1594
1595         add_hook(&assume_indexes_are_valid, OP_HOOK);
1596 }