smatch_extra.c

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