smatch_extra.c

   1 /*
   2  * sparse/smatch_extra.c
   3  *
   4  * Copyright (C) 2008 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * smatch_extra.c is supposed to track the value of every variable.
  12  *
  13  */
  14
  15 #include <stdlib.h>
  16 #include <errno.h>
  17 #ifndef __USE_ISOC99
  18 #define __USE_ISOC99
  19 #endif
  20 #include <limits.h>
  21 #include "parse.h"
  22 #include "smatch.h"
  23 #include "smatch_slist.h"
  24 #include "smatch_extra.h"
  25
  26 static int my_id;
  27
  28 struct string_list *__ignored_macros = NULL;
  29 static int in_warn_on_macro()
  30 {
  31         struct statement *stmt;
  32         char *tmp;
  33         char *macro;
  34
  35         stmt = get_current_statement();
  36         macro = get_macro_name(stmt->pos);
  37         if (!macro)
  38                 return 0;
  39
  40         FOR_EACH_PTR(__ignored_macros, tmp) {
  41                 if (!strcmp(tmp, macro))
  42                         return 1;
  43         } END_FOR_EACH_PTR(tmp);
  44         return 0;
  45 }
  46
  47 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
  48 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
  49 static struct void_fn_list *extra_mod_hooks;
  50 void add_extra_mod_hook(mod_hook *fn)
  51 {
  52         mod_hook **p = malloc(sizeof(mod_hook *));
  53         *p = fn;
  54         add_ptr_list(&extra_mod_hooks, p);
  55 }
  56
  57 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
  58 {
  59         mod_hook **fn;
  60
  61         FOR_EACH_PTR(extra_mod_hooks, fn) {
  62                 (*fn)(name, sym, state);
  63         } END_FOR_EACH_PTR(fn);
  64 }
  65
  66 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
  67 {
  68         if (in_warn_on_macro())
  69                 return NULL;
  70         remove_from_equiv(name, sym);
  71         call_extra_mod_hooks(name, sym, state);
  72         return set_state(SMATCH_EXTRA, name, sym, state);
  73 }
  74
  75 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
  76 {
  77         struct symbol *sym;
  78         char *name;
  79         struct sm_state *ret = NULL;
  80
  81         expr = strip_expr(expr);
  82         name = expr_to_var_sym(expr, &sym);
  83         if (!name || !sym)
  84                 goto free;
  85         ret = set_extra_mod(name, sym, state);
  86 free:
  87         free_string(name);
  88         return ret;
  89 }
  90
  91 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
  92 {
  93         struct relation *rel;
  94         struct smatch_state *orig_state;
  95
  96         orig_state = get_state(SMATCH_EXTRA, name, sym);
  97
  98         if (!estate_related(orig_state)) {
  99                 set_state(SMATCH_EXTRA, name, sym, state);
 100                 return;
 101         }
 102
 103         set_related(state, estate_related(orig_state));
 104         FOR_EACH_PTR(estate_related(orig_state), rel) {
 105                 if (option_debug_related)
 106                         sm_msg("updating related %s to %s", rel->name, state->name);
 107                 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
 108         } END_FOR_EACH_PTR(rel);
 109 }
 110
 111 /*
 112  * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
 113  */
 114 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
 115 {
 116         char *name;
 117         struct symbol *sym;
 118
 119         name = expr_to_var_sym(expr, &sym);
 120         if (!name || !sym)
 121                 goto free;
 122         set_extra_nomod(name, sym, state);
 123 free:
 124         free_string(name);
 125
 126 }
 127
 128 static void set_extra_true_false(const char *name, struct symbol *sym,
 129                         struct smatch_state *true_state,
 130                         struct smatch_state *false_state)
 131 {
 132         struct relation *rel;
 133         struct smatch_state *orig_state;
 134
 135         if (in_warn_on_macro())
 136                 return;
 137
 138         orig_state = get_state(SMATCH_EXTRA, name, sym);
 139
 140         if (!estate_related(orig_state)) {
 141                 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
 142                 return;
 143         }
 144
 145         if (true_state)
 146                 set_related(true_state, estate_related(orig_state));
 147         if (false_state)
 148                 set_related(false_state, estate_related(orig_state));
 149
 150         FOR_EACH_PTR(estate_related(orig_state), rel) {
 151                 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
 152                                 true_state, false_state);
 153         } END_FOR_EACH_PTR(rel);
 154 }
 155
 156 static void set_extra_expr_true_false(struct expression *expr,
 157                 struct smatch_state *true_state,
 158                 struct smatch_state *false_state)
 159 {
 160         char *name;
 161         struct symbol *sym;
 162
 163         expr = strip_expr(expr);
 164         name = expr_to_var_sym(expr, &sym);
 165         if (!name || !sym)
 166                 goto free;
 167         set_extra_true_false(name, sym, true_state, false_state);
 168 free:
 169         free_string(name);
 170 }
 171
 172 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 173 {
 174         struct expression *iter_var;
 175         struct expression *condition;
 176         struct sm_state *sm;
 177         struct smatch_state *estate;
 178         sval_t start;
 179
 180         condition = strip_expr(loop->iterator_pre_condition);
 181         if (!condition)
 182                 return NULL;
 183         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 184                 return NULL;
 185         if (condition->op != SPECIAL_DECREMENT)
 186                 return NULL;
 187
 188         iter_var = condition->unop;
 189         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 190         if (!sm)
 191                 return NULL;
 192         if (sval_cmp_val(estate_min(sm->state), 0) < 0)
 193                 return NULL;
 194         start = estate_max(sm->state);
 195         if  (sval_cmp_val(start, 0) <= 0)
 196                 return NULL;
 197         if (!sval_is_max(start))
 198                 start.value--;
 199
 200         if (condition->type == EXPR_PREOP) {
 201                 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
 202                 if (estate_has_hard_max(sm->state))
 203                         estate_set_hard_max(estate);
 204                 set_extra_expr_mod(iter_var, estate);
 205         }
 206         if (condition->type == EXPR_POSTOP) {
 207                 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
 208                 if (estate_has_hard_max(sm->state))
 209                         estate_set_hard_max(estate);
 210                 set_extra_expr_mod(iter_var, estate);
 211         }
 212         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 213 }
 214
 215 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 216                                                 struct expression *condition)
 217 {
 218         struct expression *iter_var;
 219         struct sm_state *sm;
 220         struct smatch_state *estate;
 221         sval_t start, end, dummy;
 222
 223         iter_var = iter_expr->unop;
 224         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 225         if (!sm)
 226                 return NULL;
 227         if (!estate_get_single_value(sm->state, &start))
 228                 return NULL;
 229         if (!get_implied_max(condition->right, &end))
 230                 end = sval_type_max(get_type(iter_var));
 231
 232         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 233                 return NULL;
 234
 235         switch (condition->op) {
 236         case SPECIAL_NOTEQUAL:
 237         case '<':
 238                 if (!sval_is_min(end))
 239                         end.value--;
 240                 break;
 241         case SPECIAL_LTE:
 242                 break;
 243         default:
 244                 return NULL;
 245         }
 246         if (sval_cmp(end, start) < 0)
 247                 return NULL;
 248         estate = alloc_estate_range(start, end);
 249         if (get_hard_max(condition->right, &dummy))
 250                 estate_set_hard_max(estate);
 251         set_extra_expr_mod(iter_var, estate);
 252         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 253 }
 254
 255 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 256                                                 struct expression *condition)
 257 {
 258         struct expression *iter_var;
 259         struct sm_state *sm;
 260         struct smatch_state *estate;
 261         sval_t start, end;
 262
 263         iter_var = iter_expr->unop;
 264         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 265         if (!sm)
 266                 return NULL;
 267         if (!estate_get_single_value(sm->state, &start))
 268                 return NULL;
 269         if (!get_implied_min(condition->right, &end))
 270                 end = sval_type_min(get_type(iter_var));
 271         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 272                 return NULL;
 273
 274         switch (condition->op) {
 275         case SPECIAL_NOTEQUAL:
 276         case '>':
 277                 if (!sval_is_min(end) && !sval_is_max(end))
 278                         end.value++;
 279                 break;
 280         case SPECIAL_GTE:
 281                 break;
 282         default:
 283                 return NULL;
 284         }
 285         if (sval_cmp(end, start) > 0)
 286                 return NULL;
 287         estate = alloc_estate_range(end, start);
 288         estate_set_hard_max(estate);
 289         set_extra_expr_mod(iter_var, estate);
 290         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 291 }
 292
 293 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 294 {
 295         struct expression *iter_expr;
 296         struct expression *condition;
 297
 298         if (!loop->iterator_post_statement)
 299                 return NULL;
 300         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 301                 return NULL;
 302         iter_expr = loop->iterator_post_statement->expression;
 303         if (!loop->iterator_pre_condition)
 304                 return NULL;
 305         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 306                 return NULL;
 307         condition = loop->iterator_pre_condition;
 308
 309         if (iter_expr->op == SPECIAL_INCREMENT)
 310                 return handle_canonical_for_inc(iter_expr, condition);
 311         if (iter_expr->op == SPECIAL_DECREMENT)
 312                 return handle_canonical_for_dec(iter_expr, condition);
 313         return NULL;
 314 }
 315
 316 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 317 {
 318         struct sm_state *ret;
 319
 320         __push_fake_cur_slist();
 321         if (!loop->iterator_post_statement)
 322                 ret = handle_canonical_while_count_down(loop);
 323         else
 324                 ret = handle_canonical_for_loops(loop);
 325         *slist = __pop_fake_cur_slist();
 326         return ret;
 327 }
 328
 329 int __iterator_unchanged(struct sm_state *sm)
 330 {
 331         if (!sm)
 332                 return 0;
 333         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 334                 return 1;
 335         return 0;
 336 }
 337
 338 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 339 {
 340         sval_t after_value;
 341
 342         /* paranoid checking.  prolly not needed */
 343         condition = strip_expr(condition);
 344         if (!condition)
 345                 return;
 346         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 347                 return;
 348         if (condition->op != SPECIAL_DECREMENT)
 349                 return;
 350         after_value = estate_min(sm->state);
 351         after_value.value--;
 352         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
 353 }
 354
 355 void __extra_pre_loop_hook_after(struct sm_state *sm,
 356                                 struct statement *iterator,
 357                                 struct expression *condition)
 358 {
 359         struct expression *iter_expr;
 360         sval_t limit;
 361         struct smatch_state *state;
 362
 363         if (!iterator) {
 364                 while_count_down_after(sm, condition);
 365                 return;
 366         }
 367
 368         iter_expr = iterator->expression;
 369
 370         if (condition->type != EXPR_COMPARE)
 371                 return;
 372         if (iter_expr->op == SPECIAL_INCREMENT) {
 373                 limit = sval_binop(estate_max(sm->state), '+',
 374                                    sval_type_val(estate_type(sm->state), 1));
 375         } else {
 376                 limit = sval_binop(estate_min(sm->state), '-',
 377                                    sval_type_val(estate_type(sm->state), 1));
 378         }
 379         if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
 380                 if (iter_expr->op == SPECIAL_INCREMENT)
 381                         state = alloc_estate_range(estate_min(sm->state), limit);
 382                 else
 383                         state = alloc_estate_range(limit, estate_max(sm->state));
 384         } else {
 385                 state = alloc_estate_sval(limit);
 386         }
 387         if (!estate_has_hard_max(sm->state))
 388                 estate_clear_hard_max(state);
 389         set_extra_mod(sm->name, sm->sym, state);
 390 }
 391
 392 static struct state_list *unmatched_slist;
 393 static struct smatch_state *unmatched_state(struct sm_state *sm)
 394 {
 395         struct smatch_state *state;
 396
 397         if (unmatched_slist) {
 398                 state = get_state_slist(unmatched_slist, SMATCH_EXTRA, sm->name, sm->sym);
 399                 if (state)
 400                         return state;
 401         }
 402         return alloc_estate_whole(estate_type(sm->state));
 403 }
 404
 405 static void clear_the_pointed_at(struct expression *expr, struct state_list *slist)
 406 {
 407         char *name;
 408         struct symbol *sym;
 409         struct sm_state *tmp;
 410
 411         name = expr_to_var_sym(expr, &sym);
 412         if (!name || !sym)
 413                 goto free;
 414
 415         FOR_EACH_PTR(slist, tmp) {
 416                 if (tmp->name[0] != '*')
 417                         continue;
 418                 if (tmp->sym != sym)
 419                         continue;
 420                 if (strcmp(tmp->name + 1, name) != 0)
 421                         continue;
 422                 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
 423         } END_FOR_EACH_PTR(tmp);
 424
 425 free:
 426         free_string(name);
 427 }
 428
 429 static void match_function_call(struct expression *expr)
 430 {
 431         struct expression *arg;
 432         struct expression *tmp;
 433         struct state_list *slist;
 434
 435         slist = get_all_states(SMATCH_EXTRA);
 436
 437         FOR_EACH_PTR(expr->args, arg) {
 438                 tmp = strip_expr(arg);
 439                 if (tmp->type == EXPR_PREOP && tmp->op == '&')
 440                         set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
 441                 else
 442                         clear_the_pointed_at(tmp, slist);
 443         } END_FOR_EACH_PTR(arg);
 444
 445         free_slist(&slist);
 446 }
 447
 448 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 449 {
 450         if (!one || !two)
 451                 return 0;
 452         if (one->type == SYM_PTR && two->type == SYM_PTR)
 453                 return 1;
 454         return types_equiv(one, two);
 455 }
 456
 457 static int op_remove_assign(int op)
 458 {
 459         switch (op) {
 460         case SPECIAL_ADD_ASSIGN:
 461                 return '+';
 462         case SPECIAL_SUB_ASSIGN:
 463                 return '-';
 464         case SPECIAL_MUL_ASSIGN:
 465                 return '*';
 466         case SPECIAL_DIV_ASSIGN:
 467                 return '/';
 468         case SPECIAL_MOD_ASSIGN:
 469                 return '%';
 470         case SPECIAL_AND_ASSIGN:
 471                 return '&';
 472         case SPECIAL_OR_ASSIGN:
 473                 return '|';
 474         case SPECIAL_XOR_ASSIGN:
 475                 return '^';
 476         case SPECIAL_SHL_ASSIGN:
 477                 return SPECIAL_LEFTSHIFT;
 478         case SPECIAL_SHR_ASSIGN:
 479                 return SPECIAL_RIGHTSHIFT;
 480         default:
 481                 return op;
 482         }
 483 }
 484
 485 static void match_assign(struct expression *expr)
 486 {
 487         struct range_list *rl = NULL;
 488         struct expression *left;
 489         struct expression *right;
 490         struct expression *binop_expr;
 491         struct symbol *right_sym;
 492         char *right_name = NULL;
 493         struct symbol *sym;
 494         char *name;
 495         sval_t value;
 496         int known;
 497         sval_t right_min, right_max;
 498         sval_t tmp;
 499
 500         if (is_condition(expr->right))
 501                 return;
 502         left = strip_expr(expr->left);
 503         name = expr_to_var_sym(left, &sym);
 504         if (!name)
 505                 return;
 506         right = strip_parens(expr->right);
 507         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 508                 right = strip_parens(right->left);
 509
 510         if (expr->op == '=' && strip_expr(right)->type == EXPR_CALL)
 511                 goto free;  /* these are handled in smatch_function_hooks.c */
 512
 513         right_name = expr_to_var_sym(right, &right_sym);
 514         if (expr->op == '=' && right_name && right_sym &&
 515             types_equiv_or_pointer(get_type(expr->left), get_type(expr->right))) {
 516                 set_equiv(left, right);
 517                 goto free;
 518         }
 519
 520         right_min = sval_type_min(get_type(expr->right));
 521         right_max = sval_type_max(get_type(expr->right));
 522
 523         known = get_implied_value(right, &value);
 524         switch (expr->op) {
 525         case '=': {
 526                 struct smatch_state *state;
 527
 528                 if (get_implied_rl(right, &rl)) {
 529                         rl = cast_rl(get_type(expr->left), rl);
 530                         state = alloc_estate_rl(rl);
 531                         if (get_hard_max(right, &tmp))
 532                                 estate_set_hard_max(state);
 533                 } else {
 534                         rl = alloc_whole_rl(get_type(right));
 535                         rl = cast_rl(get_type(expr->left), rl);
 536                         state = alloc_estate_rl(rl);
 537                 }
 538                 set_extra_mod(name, sym, state);
 539                 goto free;
 540         }
 541         case SPECIAL_ADD_ASSIGN:
 542                 if (get_implied_min(left, &tmp)) {
 543                         if (known)
 544                                 right_min = sval_binop(tmp, '+', value);
 545                         else
 546                                 right_min = tmp;
 547                 }
 548                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 549                         right_max = sval_binop(tmp, '+', value);
 550                 break;
 551         case SPECIAL_SUB_ASSIGN:
 552                 if (get_implied_max(left, &tmp)) {
 553                         if (known)
 554                                 right_max = sval_binop(tmp, '-', value);
 555                         else
 556                                 right_max = tmp;
 557                 }
 558                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 559                         right_min = sval_binop(tmp, '-', value);
 560                 break;
 561         case SPECIAL_AND_ASSIGN:
 562         case SPECIAL_MOD_ASSIGN:
 563                 binop_expr = binop_expression(expr->left,
 564                                               op_remove_assign(expr->op),
 565                                               expr->right);
 566                 if (get_implied_rl(binop_expr, &rl)) {
 567                         rl = cast_rl(get_type(expr->left), rl);
 568                         set_extra_mod(name, sym, alloc_estate_rl(rl));
 569                         goto free;
 570                 }
 571         }
 572         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 573                 rl = cast_rl(get_type(expr->left), alloc_rl(right_min, right_max));
 574         else
 575                 rl = alloc_whole_rl(get_type(expr->left));
 576         set_extra_mod(name, sym, alloc_estate_rl(rl));
 577 free:
 578         free_string(right_name);
 579         free_string(name);
 580 }
 581
 582 static void reset_struct_members(struct sm_state *sm)
 583 {
 584         if (!estate_rl(sm->state))
 585                 return;
 586         set_extra_mod(sm->name, sm->sym, alloc_estate_whole(estate_type(sm->state)));
 587 }
 588
 589 static struct smatch_state *increment_state(struct smatch_state *state)
 590 {
 591         sval_t min = estate_min(state);
 592         sval_t max = estate_max(state);
 593
 594         if (!estate_rl(state))
 595                 return NULL;
 596
 597         if (inside_loop())
 598                 max = sval_type_max(max.type);
 599
 600         if (!sval_is_min(min) && !sval_is_max(min))
 601                 min.value++;
 602         if (!sval_is_min(max) && !sval_is_max(max))
 603                 max.value++;
 604         return alloc_estate_range(min, max);
 605 }
 606
 607 static struct smatch_state *decrement_state(struct smatch_state *state)
 608 {
 609         sval_t min = estate_min(state);
 610         sval_t max = estate_max(state);
 611
 612         if (!estate_rl(state))
 613                 return NULL;
 614
 615         if (inside_loop())
 616                 min = sval_type_min(min.type);
 617
 618         if (!sval_is_min(min) && !sval_is_max(min))
 619                 min.value--;
 620         if (!sval_is_min(max) && !sval_is_max(max))
 621                 max.value--;
 622         return alloc_estate_range(min, max);
 623 }
 624
 625 static void unop_expr(struct expression *expr)
 626 {
 627         struct smatch_state *state;
 628
 629         if (expr->smatch_flags & Handled)
 630                 return;
 631
 632         switch (expr->op) {
 633         case SPECIAL_INCREMENT:
 634                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 635                 state = increment_state(state);
 636                 if (!state)
 637                         state = alloc_estate_whole(get_type(expr));
 638                 set_extra_expr_mod(expr->unop, state);
 639                 break;
 640         case SPECIAL_DECREMENT:
 641                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 642                 state = decrement_state(state);
 643                 if (!state)
 644                         state = alloc_estate_whole(get_type(expr));
 645                 set_extra_expr_mod(expr->unop, state);
 646                 break;
 647         default:
 648                 return;
 649         }
 650 }
 651
 652 static void asm_expr(struct statement *stmt)
 653 {
 654
 655         struct expression *expr;
 656         int state = 0;
 657
 658         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 659                 switch (state) {
 660                 case 0: /* identifier */
 661                 case 1: /* constraint */
 662                         state++;
 663                         continue;
 664                 case 2: /* expression */
 665                         state = 0;
 666                         set_extra_expr_mod(expr, alloc_estate_whole(get_type(expr)));
 667                         continue;
 668                 }
 669         } END_FOR_EACH_PTR(expr);
 670 }
 671
 672 static void delete_state_tracker(struct tracker *t)
 673 {
 674         remove_from_equiv(t->name, t->sym);
 675         delete_state(t->owner, t->name, t->sym);
 676 }
 677
 678 static void scoped_state_extra(const char *name, struct symbol *sym)
 679 {
 680         struct tracker *t;
 681
 682         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 683         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 684 }
 685
 686 static void match_declarations(struct symbol *sym)
 687 {
 688         const char *name;
 689
 690         if (sym->ident) {
 691                 name = sym->ident->name;
 692                 if (!sym->initializer) {
 693                         set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
 694                         scoped_state_extra(name, sym);
 695                 }
 696         }
 697 }
 698
 699 static void check_dereference(struct expression *expr)
 700 {
 701         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 702 }
 703
 704 static void match_dereferences(struct expression *expr)
 705 {
 706         if (expr->type != EXPR_PREOP)
 707                 return;
 708         check_dereference(expr->unop);
 709 }
 710
 711 static void match_pointer_as_array(struct expression *expr)
 712 {
 713         if (!is_array(expr))
 714                 return;
 715         check_dereference(expr->unop->left);
 716 }
 717
 718 static void set_param_dereferenced(struct expression *arg, char *unused)
 719 {
 720         check_dereference(arg);
 721 }
 722
 723 static void match_function_def(struct symbol *sym)
 724 {
 725         struct symbol *arg;
 726
 727         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 728                 if (!arg->ident)
 729                         continue;
 730                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 731         } END_FOR_EACH_PTR(arg);
 732 }
 733
 734 static int match_func_comparison(struct expression *expr)
 735 {
 736         struct expression *left = strip_expr(expr->left);
 737         struct expression *right = strip_expr(expr->right);
 738         sval_t sval;
 739
 740         if (left->type == EXPR_CALL) {
 741                 if (!get_implied_value(right, &sval))
 742                         return 1;
 743                 function_comparison(expr->op, left, sval, 1);
 744                 return 1;
 745         }
 746
 747         if (right->type == EXPR_CALL) {
 748                 if (!get_implied_value(left, &sval))
 749                         return 1;
 750                 function_comparison(expr->op, right, sval, 0);
 751                 return 1;
 752         }
 753
 754         return 0;
 755 }
 756
 757 static sval_t add_one(sval_t sval)
 758 {
 759         sval.value++;
 760         return sval;
 761 }
 762
 763 static sval_t sub_one(sval_t sval)
 764 {
 765         sval.value--;
 766         return sval;
 767 }
 768
 769 static void match_comparison(struct expression *expr)
 770 {
 771         struct expression *left = strip_expr(expr->left);
 772         struct expression *right = strip_expr(expr->right);
 773         struct symbol *type;
 774         struct range_list *left_orig;
 775         struct range_list *left_true;
 776         struct range_list *left_false;
 777         struct range_list *right_orig;
 778         struct range_list *right_true;
 779         struct range_list *right_false;
 780         struct smatch_state *left_true_state;
 781         struct smatch_state *left_false_state;
 782         struct smatch_state *right_true_state;
 783         struct smatch_state *right_false_state;
 784         sval_t min, max, dummy;
 785         int left_postop = 0;
 786         int right_postop = 0;
 787
 788         if (match_func_comparison(expr))
 789                 return;
 790
 791         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 792                 if (left->type == EXPR_POSTOP) {
 793                         left->smatch_flags |= Handled;
 794                         left_postop = left->op;
 795                 }
 796                 left = strip_expr(left->unop);
 797         }
 798         while (left->type == EXPR_ASSIGNMENT)
 799                 left = strip_expr(left->left);
 800
 801         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 802                 if (right->type == EXPR_POSTOP) {
 803                         right->smatch_flags |= Handled;
 804                         right_postop = right->op;
 805                 }
 806                 right = strip_expr(right->unop);
 807         }
 808
 809         type = get_type(expr);
 810         if (!type)
 811                 type = &llong_ctype;
 812
 813         if (get_implied_rl(left, &left_orig)) {
 814                 left_orig = cast_rl(type, left_orig);
 815         } else {
 816                 min = sval_type_min(get_type(left));
 817                 max = sval_type_max(get_type(left));
 818                 left_orig = cast_rl(type, alloc_rl(min, max));
 819         }
 820
 821         if (get_implied_rl(right, &right_orig)) {
 822                 right_orig = cast_rl(type, right_orig);
 823         } else {
 824                 min = sval_type_min(get_type(right));
 825                 max = sval_type_max(get_type(right));
 826                 right_orig = cast_rl(type, alloc_rl(min, max));
 827         }
 828         min = sval_type_min(type);
 829         max = sval_type_max(type);
 830
 831         left_true = clone_rl(left_orig);
 832         left_false = clone_rl(left_orig);
 833         right_true = clone_rl(right_orig);
 834         right_false = clone_rl(right_orig);
 835
 836         switch (expr->op) {
 837         case '<':
 838         case SPECIAL_UNSIGNED_LT:
 839                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 840                 if (!sval_is_min(rl_min(right_orig))) {
 841                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 842                 }
 843
 844                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 845                 if (!sval_is_max(rl_max(left_orig)))
 846                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 847                 break;
 848         case SPECIAL_UNSIGNED_LTE:
 849         case SPECIAL_LTE:
 850                 if (!sval_is_max(rl_max(right_orig)))
 851                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 852                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 853
 854                 if (!sval_is_min(rl_min(left_orig)))
 855                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 856                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 857
 858                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 859                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 860                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 861                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 862                 break;
 863         case SPECIAL_EQUAL:
 864                 if (!sval_is_max(rl_max(right_orig))) {
 865                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 866                 }
 867                 if (!sval_is_min(rl_min(right_orig))) {
 868                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 869                 }
 870                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 871                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 872
 873                 if (!sval_is_max(rl_max(left_orig)))
 874                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 875                 if (!sval_is_min(rl_min(left_orig)))
 876                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 877                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 878                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 879                 break;
 880         case SPECIAL_UNSIGNED_GTE:
 881         case SPECIAL_GTE:
 882                 if (!sval_is_min(rl_min(right_orig)))
 883                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 884                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 885
 886                 if (!sval_is_max(rl_max(left_orig)))
 887                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 888                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 889
 890                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 891                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 892                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 893                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 894                 break;
 895         case '>':
 896         case SPECIAL_UNSIGNED_GT:
 897                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 898                 if (!sval_is_max(rl_max(right_orig)))
 899                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 900
 901                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 902                 if (!sval_is_min(rl_min(left_orig)))
 903                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 904                 break;
 905         case SPECIAL_NOTEQUAL:
 906                 if (!sval_is_max(rl_max(right_orig)))
 907                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 908                 if (!sval_is_min(rl_min(right_orig)))
 909                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 910                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 911                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 912
 913                 if (!sval_is_max(rl_max(left_orig)))
 914                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 915                 if (!sval_is_min(rl_min(left_orig)))
 916                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 917                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 918                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 919                 break;
 920         default:
 921                 return;
 922         }
 923
 924         left_true = rl_truncate_cast(get_type(left), left_true);
 925         left_false = rl_truncate_cast(get_type(left), left_false);
 926         right_true = rl_truncate_cast(get_type(right), right_true);
 927         right_false = rl_truncate_cast(get_type(right), right_false);
 928
 929         left_true_state = alloc_estate_rl(left_true);
 930         left_false_state = alloc_estate_rl(left_false);
 931         right_true_state = alloc_estate_rl(right_true);
 932         right_false_state = alloc_estate_rl(right_false);
 933
 934         switch (expr->op) {
 935         case '<':
 936         case SPECIAL_UNSIGNED_LT:
 937         case SPECIAL_UNSIGNED_LTE:
 938         case SPECIAL_LTE:
 939                 if (get_hard_max(right, &dummy))
 940                         estate_set_hard_max(left_true_state);
 941                 if (get_hard_max(left, &dummy))
 942                         estate_set_hard_max(right_false_state);
 943                 break;
 944         case '>':
 945         case SPECIAL_UNSIGNED_GT:
 946         case SPECIAL_UNSIGNED_GTE:
 947         case SPECIAL_GTE:
 948                 if (get_hard_max(left, &dummy))
 949                         estate_set_hard_max(right_true_state);
 950                 if (get_hard_max(right, &dummy))
 951                         estate_set_hard_max(left_false_state);
 952                 break;
 953         }
 954
 955         if (get_hard_max(left, &dummy)) {
 956                 estate_set_hard_max(left_true_state);
 957                 estate_set_hard_max(left_false_state);
 958         }
 959         if (get_hard_max(right, &dummy)) {
 960                 estate_set_hard_max(right_true_state);
 961                 estate_set_hard_max(right_false_state);
 962         }
 963
 964         if (left_postop == SPECIAL_INCREMENT) {
 965                 left_true_state = increment_state(left_true_state);
 966                 left_false_state = increment_state(left_false_state);
 967         }
 968         if (left_postop == SPECIAL_DECREMENT) {
 969                 left_true_state = decrement_state(left_true_state);
 970                 left_false_state = decrement_state(left_false_state);
 971         }
 972         if (right_postop == SPECIAL_INCREMENT) {
 973                 right_true_state = increment_state(right_true_state);
 974                 right_false_state = increment_state(right_false_state);
 975         }
 976         if (right_postop == SPECIAL_DECREMENT) {
 977                 right_true_state = decrement_state(right_true_state);
 978                 right_false_state = decrement_state(right_false_state);
 979         }
 980
 981         set_extra_expr_true_false(left, left_true_state, left_false_state);
 982         set_extra_expr_true_false(right, right_true_state, right_false_state);
 983 }
 984
 985 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 986 void __extra_match_condition(struct expression *expr)
 987 {
 988         struct symbol *sym;
 989         char *name;
 990         struct smatch_state *pre_state;
 991         struct smatch_state *true_state;
 992         struct smatch_state *false_state;
 993
 994         expr = strip_expr(expr);
 995         switch (expr->type) {
 996         case EXPR_CALL:
 997                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 998                 return;
 999         case EXPR_PREOP:
1000         case EXPR_SYMBOL:
1001         case EXPR_DEREF: {
1002                 sval_t zero;
1003
1004                 zero = sval_blank(expr);
1005                 zero.value = 0;
1006
1007                 name = expr_to_var_sym(expr, &sym);
1008                 if (!name)
1009                         return;
1010                 pre_state = get_state(my_id, name, sym);
1011                 true_state = estate_filter_sval(pre_state, zero);
1012                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1013                         false_state = alloc_estate_sval(zero);
1014                 else
1015                         false_state = alloc_estate_empty();
1016                 set_extra_true_false(name, sym, true_state, false_state);
1017                 free_string(name);
1018                 return;
1019         }
1020         case EXPR_COMPARE:
1021                 match_comparison(expr);
1022                 return;
1023         case EXPR_ASSIGNMENT:
1024                 __extra_match_condition(expr->left);
1025                 return;
1026         }
1027 }
1028
1029 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1030 int implied_not_equal(struct expression *expr, long long val)
1031 {
1032         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1033 }
1034
1035 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1036 {
1037         if (estate_is_whole(state))
1038                 return;
1039         sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1040 }
1041
1042 static void db_limited_before(void)
1043 {
1044         unmatched_slist = clone_slist(__get_cur_slist());
1045 }
1046
1047 static void db_limited_after(void)
1048 {
1049         free_slist(&unmatched_slist);
1050 }
1051
1052 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value)
1053 {
1054         struct expression *arg;
1055         char *name;
1056         struct symbol *sym;
1057         struct sm_state *sm;
1058         struct symbol *type;
1059         struct range_list *rl;
1060         struct range_list *limit;
1061         struct range_list *new;
1062
1063         while (expr->type == EXPR_ASSIGNMENT)
1064                 expr = strip_expr(expr->right);
1065         if (expr->type != EXPR_CALL)
1066                 return;
1067
1068         arg = get_argument_from_call_expr(expr->args, param);
1069         if (!arg)
1070                 return;
1071
1072         name = get_variable_from_key(arg, key, &sym);
1073         if (!name || !sym)
1074                 goto free;
1075
1076         sm = get_sm_state(SMATCH_EXTRA, name, sym);
1077         type = get_member_type_from_key(arg, key);
1078         if (sm)
1079                 rl = estate_rl(sm->state);
1080         else
1081                 rl = alloc_whole_rl(type);
1082
1083         str_to_rl(type, value, &limit);
1084         new = rl_intersection(rl, limit);
1085
1086         /* We want to preserve the implications here */
1087         if (sm && rl_equiv(estate_rl(sm->state), new))
1088                 __set_sm(sm);
1089         else
1090                 set_extra_nomod(name, sym, alloc_estate_rl(new));
1091
1092 free:
1093         free_string(name);
1094 }
1095
1096 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1097 {
1098         struct expression *arg;
1099         char *name;
1100         struct symbol *sym;
1101         struct symbol *type;
1102         struct smatch_state *state;
1103         struct range_list *added = NULL;
1104         struct range_list *new;
1105
1106         while (expr->type == EXPR_ASSIGNMENT)
1107                 expr = strip_expr(expr->right);
1108         if (expr->type != EXPR_CALL)
1109                 return;
1110
1111         arg = get_argument_from_call_expr(expr->args, param);
1112         if (!arg)
1113                 return;
1114         name = get_variable_from_key(arg, key, &sym);
1115         if (!name || !sym)
1116                 goto free;
1117
1118         type = get_member_type_from_key(arg, key);
1119         state = get_state(SMATCH_EXTRA, name, sym);
1120         if (state) {
1121                 str_to_rl(type, value, &added);
1122                 new = rl_union(estate_rl(state), added);
1123         } else {
1124                 new = alloc_whole_rl(type);
1125         }
1126
1127         set_extra_mod(name, sym, alloc_estate_rl(new));
1128 free:
1129         free_string(name);
1130 }
1131
1132 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
1133 {
1134         struct expression *arg;
1135         struct symbol *type;
1136         struct range_list *rl;
1137         char member_name[256];
1138         char *name;
1139         struct symbol *sym;
1140
1141         while (expr->type == EXPR_ASSIGNMENT)
1142                 expr = strip_expr(expr->right);
1143         if (expr->type != EXPR_CALL)
1144                 return;
1145         arg = get_argument_from_call_expr(expr->args, param);
1146         arg = strip_expr(arg);
1147         if (!arg)
1148                 return;
1149
1150         if (strcmp(key, "*$$") == 0) {
1151                 struct symbol *sym;
1152                 char buf[256];
1153                 char *name;
1154
1155                 if (arg->type == EXPR_PREOP && arg->op == '&') {
1156                         arg = strip_expr(arg->unop);
1157                         name = expr_to_var_sym(arg, &sym);
1158                 } else {
1159                         char *tmp = expr_to_var_sym(arg, &sym);
1160
1161                         if (!tmp)
1162                                 return;
1163                         snprintf(buf, sizeof(buf), "*%s", tmp);
1164                         name = alloc_string(buf);
1165                         free_string(tmp);
1166                 }
1167                 if (!name || !sym) {
1168                         free_string(name);
1169                         return;
1170                 }
1171                 type = get_type(arg);
1172                 str_to_rl(type, value, &rl);
1173                 set_extra_mod(name, sym, alloc_estate_rl(rl));
1174                 free_string(name);
1175                 return;
1176         }
1177
1178         if (arg->type == EXPR_PREOP && arg->op == '&') {
1179                 arg = strip_expr(arg->unop);
1180                 name = expr_to_var_sym(arg, &sym);
1181                 if (!name || !sym)
1182                         goto free;
1183                 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
1184         } else {
1185                 name = expr_to_var_sym(arg, &sym);
1186                 if (!name || !sym)
1187                         goto free;
1188                 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1189         }
1190         type = get_member_type_from_key(arg, key);
1191         if (!type)
1192                 goto free;
1193         str_to_rl(type, value, &rl);
1194         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1195 free:
1196         free_string(name);
1197 }
1198
1199 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1200 {
1201         struct symbol *type;
1202         struct symbol *sym;
1203         char *name;
1204         char member_name[256];
1205         struct range_list *rl;
1206
1207         if (expr->type != EXPR_ASSIGNMENT)
1208                 return;
1209
1210         name = expr_to_var_sym(expr->left, &sym);
1211         if (!name || !sym)
1212                 goto free;
1213         snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1214         type = get_member_type_from_key(expr->left, key);
1215         if (!type)
1216                 return;
1217         str_to_rl(type, value, &rl);
1218         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1219
1220 free:
1221         free_string(name);
1222 }
1223
1224 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1225 {
1226         if (estate_is_whole(state))
1227                 return;
1228
1229         sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1230                         printed_name, state->name);
1231 }
1232
1233 static void match_call_info(struct expression *expr)
1234 {
1235         struct range_list *rl = NULL;
1236         struct expression *arg;
1237         struct symbol *type;
1238         int i = 0;
1239
1240         FOR_EACH_PTR(expr->args, arg) {
1241                 type = get_arg_type(expr->fn, i);
1242
1243                 if (get_implied_rl(arg, &rl))
1244                         rl = cast_rl(type, rl);
1245                 else
1246                         rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1247
1248                 sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1249                 i++;
1250         } END_FOR_EACH_PTR(arg);
1251 }
1252
1253 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1254 {
1255         struct range_list *rl = NULL;
1256         struct smatch_state *state;
1257         struct symbol *type;
1258         char fullname[256];
1259
1260         if (strcmp(key, "*$$") == 0)
1261                 snprintf(fullname, sizeof(fullname), "*%s", name);
1262         else if (strncmp(key, "$$", 2) == 0)
1263                 snprintf(fullname, 256, "%s%s", name, key + 2);
1264         else
1265                 return;
1266
1267         type = get_member_type_from_key(symbol_expression(sym), key);
1268         str_to_rl(type, value, &rl);
1269         state = alloc_estate_rl(rl);
1270         set_state(SMATCH_EXTRA, fullname, sym, state);
1271 }
1272
1273 void register_smatch_extra(int id)
1274 {
1275         my_id = id;
1276
1277         add_merge_hook(my_id, &merge_estates);
1278         add_unmatched_state_hook(my_id, &unmatched_state);
1279         add_hook(&match_function_def, FUNC_DEF_HOOK);
1280         add_hook(&match_declarations, DECLARATION_HOOK);
1281         add_definition_db_callback(set_param_value, PARAM_VALUE);
1282         add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1283         add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1284         add_db_return_states_before(&db_limited_before);
1285         add_db_return_states_callback(LIMITED_VALUE, &db_param_limit_filter);
1286         add_db_return_states_callback(FILTER_VALUE, &db_param_limit_filter);
1287         add_db_return_states_callback(ADDED_VALUE, &db_param_add);
1288         add_db_return_states_after(&db_limited_after);
1289 }
1290
1291 void register_smatch_extra_late(int id)
1292 {
1293         add_hook(&match_dereferences, DEREF_HOOK);
1294         add_hook(&match_pointer_as_array, OP_HOOK);
1295         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1296         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1297         if (option_no_db)
1298                 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1299         add_hook(&match_assign, ASSIGNMENT_HOOK);
1300         add_hook(&unop_expr, OP_HOOK);
1301         add_hook(&asm_expr, ASM_HOOK);
1302
1303         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1304         add_member_info_callback(my_id, struct_member_callback);
1305         add_returned_member_callback(my_id, returned_member_callback);
1306 }