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_cast(get_type(iter_var), end);
 231         else
 232                 end = sval_type_max(get_type(iter_var));
 233
 234         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 235                 return NULL;
 236
 237         switch (condition->op) {
 238         case SPECIAL_NOTEQUAL:
 239         case '<':
 240                 if (!sval_is_min(end))
 241                         end.value--;
 242                 break;
 243         case SPECIAL_LTE:
 244                 break;
 245         default:
 246                 return NULL;
 247         }
 248         if (sval_cmp(end, start) < 0)
 249                 return NULL;
 250         estate = alloc_estate_range(start, end);
 251         if (get_hard_max(condition->right, &dummy))
 252                 estate_set_hard_max(estate);
 253         set_extra_expr_mod(iter_var, estate);
 254         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 255 }
 256
 257 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 258                                                 struct expression *condition)
 259 {
 260         struct expression *iter_var;
 261         struct sm_state *sm;
 262         struct smatch_state *estate;
 263         sval_t start, end;
 264
 265         iter_var = iter_expr->unop;
 266         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 267         if (!sm)
 268                 return NULL;
 269         if (!estate_get_single_value(sm->state, &start))
 270                 return NULL;
 271         if (!get_implied_min(condition->right, &end))
 272                 end = sval_type_min(get_type(iter_var));
 273         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 274                 return NULL;
 275
 276         switch (condition->op) {
 277         case SPECIAL_NOTEQUAL:
 278         case '>':
 279                 if (!sval_is_min(end) && !sval_is_max(end))
 280                         end.value++;
 281                 break;
 282         case SPECIAL_GTE:
 283                 break;
 284         default:
 285                 return NULL;
 286         }
 287         if (sval_cmp(end, start) > 0)
 288                 return NULL;
 289         estate = alloc_estate_range(end, start);
 290         estate_set_hard_max(estate);
 291         set_extra_expr_mod(iter_var, estate);
 292         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 293 }
 294
 295 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 296 {
 297         struct expression *iter_expr;
 298         struct expression *condition;
 299
 300         if (!loop->iterator_post_statement)
 301                 return NULL;
 302         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 303                 return NULL;
 304         iter_expr = loop->iterator_post_statement->expression;
 305         if (!loop->iterator_pre_condition)
 306                 return NULL;
 307         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 308                 return NULL;
 309         condition = loop->iterator_pre_condition;
 310
 311         if (iter_expr->op == SPECIAL_INCREMENT)
 312                 return handle_canonical_for_inc(iter_expr, condition);
 313         if (iter_expr->op == SPECIAL_DECREMENT)
 314                 return handle_canonical_for_dec(iter_expr, condition);
 315         return NULL;
 316 }
 317
 318 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 319 {
 320         struct sm_state *ret;
 321
 322         __push_fake_cur_slist();
 323         if (!loop->iterator_post_statement)
 324                 ret = handle_canonical_while_count_down(loop);
 325         else
 326                 ret = handle_canonical_for_loops(loop);
 327         *slist = __pop_fake_cur_slist();
 328         return ret;
 329 }
 330
 331 int __iterator_unchanged(struct sm_state *sm)
 332 {
 333         if (!sm)
 334                 return 0;
 335         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 336                 return 1;
 337         return 0;
 338 }
 339
 340 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 341 {
 342         sval_t after_value;
 343
 344         /* paranoid checking.  prolly not needed */
 345         condition = strip_expr(condition);
 346         if (!condition)
 347                 return;
 348         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 349                 return;
 350         if (condition->op != SPECIAL_DECREMENT)
 351                 return;
 352         after_value = estate_min(sm->state);
 353         after_value.value--;
 354         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
 355 }
 356
 357 void __extra_pre_loop_hook_after(struct sm_state *sm,
 358                                 struct statement *iterator,
 359                                 struct expression *condition)
 360 {
 361         struct expression *iter_expr;
 362         sval_t limit;
 363         struct smatch_state *state;
 364
 365         if (!iterator) {
 366                 while_count_down_after(sm, condition);
 367                 return;
 368         }
 369
 370         iter_expr = iterator->expression;
 371
 372         if (condition->type != EXPR_COMPARE)
 373                 return;
 374         if (iter_expr->op == SPECIAL_INCREMENT) {
 375                 limit = sval_binop(estate_max(sm->state), '+',
 376                                    sval_type_val(estate_type(sm->state), 1));
 377         } else {
 378                 limit = sval_binop(estate_min(sm->state), '-',
 379                                    sval_type_val(estate_type(sm->state), 1));
 380         }
 381         if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
 382                 if (iter_expr->op == SPECIAL_INCREMENT)
 383                         state = alloc_estate_range(estate_min(sm->state), limit);
 384                 else
 385                         state = alloc_estate_range(limit, estate_max(sm->state));
 386         } else {
 387                 state = alloc_estate_sval(limit);
 388         }
 389         if (!estate_has_hard_max(sm->state))
 390                 estate_clear_hard_max(state);
 391         set_extra_mod(sm->name, sm->sym, state);
 392 }
 393
 394 static struct state_list *unmatched_slist;
 395 static struct smatch_state *unmatched_state(struct sm_state *sm)
 396 {
 397         struct smatch_state *state;
 398
 399         if (unmatched_slist) {
 400                 state = get_state_slist(unmatched_slist, SMATCH_EXTRA, sm->name, sm->sym);
 401                 if (state)
 402                         return state;
 403         }
 404         return alloc_estate_whole(estate_type(sm->state));
 405 }
 406
 407 static void clear_the_pointed_at(struct expression *expr, struct state_list *slist)
 408 {
 409         char *name;
 410         struct symbol *sym;
 411         struct sm_state *tmp;
 412
 413         name = expr_to_var_sym(expr, &sym);
 414         if (!name || !sym)
 415                 goto free;
 416
 417         FOR_EACH_PTR(slist, tmp) {
 418                 if (tmp->name[0] != '*')
 419                         continue;
 420                 if (tmp->sym != sym)
 421                         continue;
 422                 if (strcmp(tmp->name + 1, name) != 0)
 423                         continue;
 424                 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
 425         } END_FOR_EACH_PTR(tmp);
 426
 427 free:
 428         free_string(name);
 429 }
 430
 431 static void match_function_call(struct expression *expr)
 432 {
 433         struct expression *arg;
 434         struct expression *tmp;
 435         struct state_list *slist;
 436
 437         slist = get_all_states(SMATCH_EXTRA);
 438
 439         FOR_EACH_PTR(expr->args, arg) {
 440                 tmp = strip_expr(arg);
 441                 if (tmp->type == EXPR_PREOP && tmp->op == '&')
 442                         set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
 443                 else
 444                         clear_the_pointed_at(tmp, slist);
 445         } END_FOR_EACH_PTR(arg);
 446
 447         free_slist(&slist);
 448 }
 449
 450 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 451 {
 452         if (!one || !two)
 453                 return 0;
 454         if (one->type == SYM_PTR && two->type == SYM_PTR)
 455                 return 1;
 456         return types_equiv(one, two);
 457 }
 458
 459 static int op_remove_assign(int op)
 460 {
 461         switch (op) {
 462         case SPECIAL_ADD_ASSIGN:
 463                 return '+';
 464         case SPECIAL_SUB_ASSIGN:
 465                 return '-';
 466         case SPECIAL_MUL_ASSIGN:
 467                 return '*';
 468         case SPECIAL_DIV_ASSIGN:
 469                 return '/';
 470         case SPECIAL_MOD_ASSIGN:
 471                 return '%';
 472         case SPECIAL_AND_ASSIGN:
 473                 return '&';
 474         case SPECIAL_OR_ASSIGN:
 475                 return '|';
 476         case SPECIAL_XOR_ASSIGN:
 477                 return '^';
 478         case SPECIAL_SHL_ASSIGN:
 479                 return SPECIAL_LEFTSHIFT;
 480         case SPECIAL_SHR_ASSIGN:
 481                 return SPECIAL_RIGHTSHIFT;
 482         default:
 483                 return op;
 484         }
 485 }
 486
 487 static void match_assign(struct expression *expr)
 488 {
 489         struct range_list *rl = NULL;
 490         struct expression *left;
 491         struct expression *right;
 492         struct expression *binop_expr;
 493         struct symbol *right_sym;
 494         struct symbol *left_type;
 495         struct symbol *right_type;
 496         char *right_name = NULL;
 497         struct symbol *sym;
 498         char *name;
 499         sval_t value;
 500         int known;
 501         sval_t right_min, right_max;
 502         sval_t tmp;
 503
 504         left = strip_expr(expr->left);
 505
 506         right = strip_expr(expr->right);
 507         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 508                 right = strip_expr(right->left);
 509
 510         if (is_condition(expr->right))
 511                 return; /* handled in smatch_condition.c */
 512         if (expr->op == '=' && right->type == EXPR_CALL)
 513                 return; /* handled in smatch_function_hooks.c */
 514
 515         name = expr_to_var_sym(left, &sym);
 516         if (!name)
 517                 return;
 518
 519         left_type = get_type(left);
 520         right_type = get_type(right);
 521
 522         right_name = expr_to_var_sym(right, &right_sym);
 523         if (expr->op == '=' && right_name && right_sym &&
 524             types_equiv_or_pointer(left_type, right_type)) {
 525                 set_equiv(left, right);
 526                 goto free;
 527         }
 528
 529         right_min = sval_type_min(right_type);
 530         right_max = sval_type_max(right_type);
 531
 532         known = get_implied_value(right, &value);
 533         switch (expr->op) {
 534         case '=': {
 535                 struct smatch_state *state;
 536
 537                 if (get_implied_rl(right, &rl)) {
 538                         rl = cast_rl(left_type, rl);
 539                         state = alloc_estate_rl(rl);
 540                         if (get_hard_max(right, &tmp))
 541                                 estate_set_hard_max(state);
 542                 } else {
 543                         rl = alloc_whole_rl(right_type);
 544                         rl = cast_rl(left_type, rl);
 545                         state = alloc_estate_rl(rl);
 546                 }
 547                 set_extra_mod(name, sym, state);
 548                 goto free;
 549         }
 550         case SPECIAL_ADD_ASSIGN:
 551                 if (get_implied_min(left, &tmp)) {
 552                         if (known)
 553                                 right_min = sval_binop(tmp, '+', value);
 554                         else
 555                                 right_min = tmp;
 556                 }
 557                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 558                         right_max = sval_binop(tmp, '+', value);
 559                 break;
 560         case SPECIAL_SUB_ASSIGN:
 561                 if (get_implied_max(left, &tmp)) {
 562                         if (known)
 563                                 right_max = sval_binop(tmp, '-', value);
 564                         else
 565                                 right_max = tmp;
 566                 }
 567                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 568                         right_min = sval_binop(tmp, '-', value);
 569                 break;
 570         case SPECIAL_AND_ASSIGN:
 571         case SPECIAL_MOD_ASSIGN:
 572                 binop_expr = binop_expression(expr->left,
 573                                               op_remove_assign(expr->op),
 574                                               expr->right);
 575                 if (get_implied_rl(binop_expr, &rl)) {
 576                         rl = cast_rl(left_type, rl);
 577                         set_extra_mod(name, sym, alloc_estate_rl(rl));
 578                         goto free;
 579                 }
 580         }
 581         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 582                 rl = cast_rl(left_type, alloc_rl(right_min, right_max));
 583         else
 584                 rl = alloc_whole_rl(left_type);
 585         set_extra_mod(name, sym, alloc_estate_rl(rl));
 586 free:
 587         free_string(right_name);
 588         free_string(name);
 589 }
 590
 591 static void reset_struct_members(struct sm_state *sm)
 592 {
 593         if (!estate_rl(sm->state))
 594                 return;
 595         set_extra_mod(sm->name, sm->sym, alloc_estate_whole(estate_type(sm->state)));
 596 }
 597
 598 static struct smatch_state *increment_state(struct smatch_state *state)
 599 {
 600         sval_t min = estate_min(state);
 601         sval_t max = estate_max(state);
 602
 603         if (!estate_rl(state))
 604                 return NULL;
 605
 606         if (inside_loop())
 607                 max = sval_type_max(max.type);
 608
 609         if (!sval_is_min(min) && !sval_is_max(min))
 610                 min.value++;
 611         if (!sval_is_min(max) && !sval_is_max(max))
 612                 max.value++;
 613         return alloc_estate_range(min, max);
 614 }
 615
 616 static struct smatch_state *decrement_state(struct smatch_state *state)
 617 {
 618         sval_t min = estate_min(state);
 619         sval_t max = estate_max(state);
 620
 621         if (!estate_rl(state))
 622                 return NULL;
 623
 624         if (inside_loop())
 625                 min = sval_type_min(min.type);
 626
 627         if (!sval_is_min(min) && !sval_is_max(min))
 628                 min.value--;
 629         if (!sval_is_min(max) && !sval_is_max(max))
 630                 max.value--;
 631         return alloc_estate_range(min, max);
 632 }
 633
 634 static void unop_expr(struct expression *expr)
 635 {
 636         struct smatch_state *state;
 637
 638         if (expr->smatch_flags & Handled)
 639                 return;
 640
 641         switch (expr->op) {
 642         case SPECIAL_INCREMENT:
 643                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 644                 state = increment_state(state);
 645                 if (!state)
 646                         state = alloc_estate_whole(get_type(expr));
 647                 set_extra_expr_mod(expr->unop, state);
 648                 break;
 649         case SPECIAL_DECREMENT:
 650                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 651                 state = decrement_state(state);
 652                 if (!state)
 653                         state = alloc_estate_whole(get_type(expr));
 654                 set_extra_expr_mod(expr->unop, state);
 655                 break;
 656         default:
 657                 return;
 658         }
 659 }
 660
 661 static void asm_expr(struct statement *stmt)
 662 {
 663
 664         struct expression *expr;
 665         int state = 0;
 666
 667         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 668                 switch (state) {
 669                 case 0: /* identifier */
 670                 case 1: /* constraint */
 671                         state++;
 672                         continue;
 673                 case 2: /* expression */
 674                         state = 0;
 675                         set_extra_expr_mod(expr, alloc_estate_whole(get_type(expr)));
 676                         continue;
 677                 }
 678         } END_FOR_EACH_PTR(expr);
 679 }
 680
 681 static void delete_state_tracker(struct tracker *t)
 682 {
 683         remove_from_equiv(t->name, t->sym);
 684         delete_state(t->owner, t->name, t->sym);
 685 }
 686
 687 static void scoped_state_extra(const char *name, struct symbol *sym)
 688 {
 689         struct tracker *t;
 690
 691         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 692         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 693 }
 694
 695 static void match_declarations(struct symbol *sym)
 696 {
 697         const char *name;
 698
 699         if (sym->ident) {
 700                 name = sym->ident->name;
 701                 if (!sym->initializer) {
 702                         set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
 703                         scoped_state_extra(name, sym);
 704                 }
 705         }
 706 }
 707
 708 static void check_dereference(struct expression *expr)
 709 {
 710         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 711 }
 712
 713 static void match_dereferences(struct expression *expr)
 714 {
 715         if (expr->type != EXPR_PREOP)
 716                 return;
 717         check_dereference(expr->unop);
 718 }
 719
 720 static void match_pointer_as_array(struct expression *expr)
 721 {
 722         if (!is_array(expr))
 723                 return;
 724         check_dereference(expr->unop->left);
 725 }
 726
 727 static void set_param_dereferenced(struct expression *arg, char *unused)
 728 {
 729         check_dereference(arg);
 730 }
 731
 732 static void match_function_def(struct symbol *sym)
 733 {
 734         struct symbol *arg;
 735
 736         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 737                 if (!arg->ident)
 738                         continue;
 739                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 740         } END_FOR_EACH_PTR(arg);
 741 }
 742
 743 static int match_func_comparison(struct expression *expr)
 744 {
 745         struct expression *left = strip_expr(expr->left);
 746         struct expression *right = strip_expr(expr->right);
 747         sval_t sval;
 748
 749         if (left->type == EXPR_CALL) {
 750                 if (!get_implied_value(right, &sval))
 751                         return 1;
 752                 function_comparison(expr->op, left, sval, 1);
 753                 return 1;
 754         }
 755
 756         if (right->type == EXPR_CALL) {
 757                 if (!get_implied_value(left, &sval))
 758                         return 1;
 759                 function_comparison(expr->op, right, sval, 0);
 760                 return 1;
 761         }
 762
 763         return 0;
 764 }
 765
 766 static sval_t add_one(sval_t sval)
 767 {
 768         sval.value++;
 769         return sval;
 770 }
 771
 772 static sval_t sub_one(sval_t sval)
 773 {
 774         sval.value--;
 775         return sval;
 776 }
 777
 778 static void match_comparison(struct expression *expr)
 779 {
 780         struct expression *left = strip_expr(expr->left);
 781         struct expression *right = strip_expr(expr->right);
 782         struct symbol *type;
 783         struct range_list *left_orig;
 784         struct range_list *left_true;
 785         struct range_list *left_false;
 786         struct range_list *right_orig;
 787         struct range_list *right_true;
 788         struct range_list *right_false;
 789         struct smatch_state *left_true_state;
 790         struct smatch_state *left_false_state;
 791         struct smatch_state *right_true_state;
 792         struct smatch_state *right_false_state;
 793         sval_t min, max, dummy;
 794         int left_postop = 0;
 795         int right_postop = 0;
 796
 797         if (match_func_comparison(expr))
 798                 return;
 799
 800         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 801                 if (left->type == EXPR_POSTOP) {
 802                         left->smatch_flags |= Handled;
 803                         left_postop = left->op;
 804                 }
 805                 left = strip_expr(left->unop);
 806         }
 807         while (left->type == EXPR_ASSIGNMENT)
 808                 left = strip_expr(left->left);
 809
 810         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 811                 if (right->type == EXPR_POSTOP) {
 812                         right->smatch_flags |= Handled;
 813                         right_postop = right->op;
 814                 }
 815                 right = strip_expr(right->unop);
 816         }
 817
 818         type = get_type(expr);
 819         if (!type)
 820                 type = &llong_ctype;
 821
 822         if (get_implied_rl(left, &left_orig)) {
 823                 left_orig = cast_rl(type, left_orig);
 824         } else {
 825                 min = sval_type_min(get_type(left));
 826                 max = sval_type_max(get_type(left));
 827                 left_orig = cast_rl(type, alloc_rl(min, max));
 828         }
 829
 830         if (get_implied_rl(right, &right_orig)) {
 831                 right_orig = cast_rl(type, right_orig);
 832         } else {
 833                 min = sval_type_min(get_type(right));
 834                 max = sval_type_max(get_type(right));
 835                 right_orig = cast_rl(type, alloc_rl(min, max));
 836         }
 837         min = sval_type_min(type);
 838         max = sval_type_max(type);
 839
 840         left_true = clone_rl(left_orig);
 841         left_false = clone_rl(left_orig);
 842         right_true = clone_rl(right_orig);
 843         right_false = clone_rl(right_orig);
 844
 845         switch (expr->op) {
 846         case '<':
 847         case SPECIAL_UNSIGNED_LT:
 848                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 849                 if (!sval_is_min(rl_min(right_orig))) {
 850                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 851                 }
 852
 853                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 854                 if (!sval_is_max(rl_max(left_orig)))
 855                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 856                 break;
 857         case SPECIAL_UNSIGNED_LTE:
 858         case SPECIAL_LTE:
 859                 if (!sval_is_max(rl_max(right_orig)))
 860                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 861                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 862
 863                 if (!sval_is_min(rl_min(left_orig)))
 864                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 865                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 866
 867                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 868                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 869                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 870                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 871                 break;
 872         case SPECIAL_EQUAL:
 873                 if (!sval_is_max(rl_max(right_orig))) {
 874                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 875                 }
 876                 if (!sval_is_min(rl_min(right_orig))) {
 877                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 878                 }
 879                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 880                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 881
 882                 if (!sval_is_max(rl_max(left_orig)))
 883                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 884                 if (!sval_is_min(rl_min(left_orig)))
 885                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 886                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 887                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 888                 break;
 889         case SPECIAL_UNSIGNED_GTE:
 890         case SPECIAL_GTE:
 891                 if (!sval_is_min(rl_min(right_orig)))
 892                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 893                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 894
 895                 if (!sval_is_max(rl_max(left_orig)))
 896                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 897                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 898
 899                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 900                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 901                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 902                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 903                 break;
 904         case '>':
 905         case SPECIAL_UNSIGNED_GT:
 906                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 907                 if (!sval_is_max(rl_max(right_orig)))
 908                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 909
 910                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 911                 if (!sval_is_min(rl_min(left_orig)))
 912                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 913                 break;
 914         case SPECIAL_NOTEQUAL:
 915                 if (!sval_is_max(rl_max(right_orig)))
 916                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 917                 if (!sval_is_min(rl_min(right_orig)))
 918                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 919                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 920                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 921
 922                 if (!sval_is_max(rl_max(left_orig)))
 923                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 924                 if (!sval_is_min(rl_min(left_orig)))
 925                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 926                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 927                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 928                 break;
 929         default:
 930                 return;
 931         }
 932
 933         left_true = rl_truncate_cast(get_type(left), left_true);
 934         left_false = rl_truncate_cast(get_type(left), left_false);
 935         right_true = rl_truncate_cast(get_type(right), right_true);
 936         right_false = rl_truncate_cast(get_type(right), right_false);
 937
 938         left_true_state = alloc_estate_rl(left_true);
 939         left_false_state = alloc_estate_rl(left_false);
 940         right_true_state = alloc_estate_rl(right_true);
 941         right_false_state = alloc_estate_rl(right_false);
 942
 943         switch (expr->op) {
 944         case '<':
 945         case SPECIAL_UNSIGNED_LT:
 946         case SPECIAL_UNSIGNED_LTE:
 947         case SPECIAL_LTE:
 948                 if (get_hard_max(right, &dummy))
 949                         estate_set_hard_max(left_true_state);
 950                 if (get_hard_max(left, &dummy))
 951                         estate_set_hard_max(right_false_state);
 952                 break;
 953         case '>':
 954         case SPECIAL_UNSIGNED_GT:
 955         case SPECIAL_UNSIGNED_GTE:
 956         case SPECIAL_GTE:
 957                 if (get_hard_max(left, &dummy))
 958                         estate_set_hard_max(right_true_state);
 959                 if (get_hard_max(right, &dummy))
 960                         estate_set_hard_max(left_false_state);
 961                 break;
 962         }
 963
 964         if (get_hard_max(left, &dummy)) {
 965                 estate_set_hard_max(left_true_state);
 966                 estate_set_hard_max(left_false_state);
 967         }
 968         if (get_hard_max(right, &dummy)) {
 969                 estate_set_hard_max(right_true_state);
 970                 estate_set_hard_max(right_false_state);
 971         }
 972
 973         if (left_postop == SPECIAL_INCREMENT) {
 974                 left_true_state = increment_state(left_true_state);
 975                 left_false_state = increment_state(left_false_state);
 976         }
 977         if (left_postop == SPECIAL_DECREMENT) {
 978                 left_true_state = decrement_state(left_true_state);
 979                 left_false_state = decrement_state(left_false_state);
 980         }
 981         if (right_postop == SPECIAL_INCREMENT) {
 982                 right_true_state = increment_state(right_true_state);
 983                 right_false_state = increment_state(right_false_state);
 984         }
 985         if (right_postop == SPECIAL_DECREMENT) {
 986                 right_true_state = decrement_state(right_true_state);
 987                 right_false_state = decrement_state(right_false_state);
 988         }
 989
 990         set_extra_expr_true_false(left, left_true_state, left_false_state);
 991         set_extra_expr_true_false(right, right_true_state, right_false_state);
 992 }
 993
 994 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 995 void __extra_match_condition(struct expression *expr)
 996 {
 997         struct symbol *sym;
 998         char *name;
 999         struct smatch_state *pre_state;
1000         struct smatch_state *true_state;
1001         struct smatch_state *false_state;
1002
1003         expr = strip_expr(expr);
1004         switch (expr->type) {
1005         case EXPR_CALL:
1006                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
1007                 return;
1008         case EXPR_PREOP:
1009         case EXPR_SYMBOL:
1010         case EXPR_DEREF: {
1011                 sval_t zero;
1012
1013                 zero = sval_blank(expr);
1014                 zero.value = 0;
1015
1016                 name = expr_to_var_sym(expr, &sym);
1017                 if (!name)
1018                         return;
1019                 pre_state = get_state(my_id, name, sym);
1020                 true_state = estate_filter_sval(pre_state, zero);
1021                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1022                         false_state = alloc_estate_sval(zero);
1023                 else
1024                         false_state = alloc_estate_empty();
1025                 set_extra_true_false(name, sym, true_state, false_state);
1026                 free_string(name);
1027                 return;
1028         }
1029         case EXPR_COMPARE:
1030                 match_comparison(expr);
1031                 return;
1032         case EXPR_ASSIGNMENT:
1033                 __extra_match_condition(expr->left);
1034                 return;
1035         }
1036 }
1037
1038 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1039 int implied_not_equal(struct expression *expr, long long val)
1040 {
1041         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1042 }
1043
1044 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1045 {
1046         if (estate_is_whole(state))
1047                 return;
1048         sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1049 }
1050
1051 static void db_limited_before(void)
1052 {
1053         unmatched_slist = clone_slist(__get_cur_slist());
1054 }
1055
1056 static void db_limited_after(void)
1057 {
1058         free_slist(&unmatched_slist);
1059 }
1060
1061 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value)
1062 {
1063         struct expression *arg;
1064         char *name;
1065         struct symbol *sym;
1066         struct sm_state *sm;
1067         struct symbol *type;
1068         struct range_list *rl;
1069         struct range_list *limit;
1070         struct range_list *new;
1071
1072         while (expr->type == EXPR_ASSIGNMENT)
1073                 expr = strip_expr(expr->right);
1074         if (expr->type != EXPR_CALL)
1075                 return;
1076
1077         arg = get_argument_from_call_expr(expr->args, param);
1078         if (!arg)
1079                 return;
1080
1081         name = get_variable_from_key(arg, key, &sym);
1082         if (!name || !sym)
1083                 goto free;
1084
1085         sm = get_sm_state(SMATCH_EXTRA, name, sym);
1086         type = get_member_type_from_key(arg, key);
1087         if (sm)
1088                 rl = estate_rl(sm->state);
1089         else
1090                 rl = alloc_whole_rl(type);
1091
1092         str_to_rl(type, value, &limit);
1093         new = rl_intersection(rl, limit);
1094
1095         /* We want to preserve the implications here */
1096         if (sm && rl_equiv(estate_rl(sm->state), new))
1097                 __set_sm(sm);
1098         else
1099                 set_extra_nomod(name, sym, alloc_estate_rl(new));
1100
1101 free:
1102         free_string(name);
1103 }
1104
1105 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1106 {
1107         struct expression *arg;
1108         char *name;
1109         struct symbol *sym;
1110         struct symbol *type;
1111         struct smatch_state *state;
1112         struct range_list *added = NULL;
1113         struct range_list *new;
1114
1115         while (expr->type == EXPR_ASSIGNMENT)
1116                 expr = strip_expr(expr->right);
1117         if (expr->type != EXPR_CALL)
1118                 return;
1119
1120         arg = get_argument_from_call_expr(expr->args, param);
1121         if (!arg)
1122                 return;
1123         name = get_variable_from_key(arg, key, &sym);
1124         if (!name || !sym)
1125                 goto free;
1126
1127         type = get_member_type_from_key(arg, key);
1128         state = get_state(SMATCH_EXTRA, name, sym);
1129         if (state) {
1130                 str_to_rl(type, value, &added);
1131                 new = rl_union(estate_rl(state), added);
1132         } else {
1133                 new = alloc_whole_rl(type);
1134         }
1135
1136         set_extra_mod(name, sym, alloc_estate_rl(new));
1137 free:
1138         free_string(name);
1139 }
1140
1141 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
1142 {
1143         struct expression *arg;
1144         struct symbol *type;
1145         struct range_list *rl;
1146         char member_name[256];
1147         char *name;
1148         struct symbol *sym;
1149
1150         while (expr->type == EXPR_ASSIGNMENT)
1151                 expr = strip_expr(expr->right);
1152         if (expr->type != EXPR_CALL)
1153                 return;
1154         arg = get_argument_from_call_expr(expr->args, param);
1155         arg = strip_expr(arg);
1156         if (!arg)
1157                 return;
1158
1159         if (strcmp(key, "*$$") == 0) {
1160                 struct symbol *sym;
1161                 char buf[256];
1162                 char *name;
1163
1164                 if (arg->type == EXPR_PREOP && arg->op == '&') {
1165                         arg = strip_expr(arg->unop);
1166                         name = expr_to_var_sym(arg, &sym);
1167                 } else {
1168                         char *tmp = expr_to_var_sym(arg, &sym);
1169
1170                         if (!tmp)
1171                                 return;
1172                         snprintf(buf, sizeof(buf), "*%s", tmp);
1173                         name = alloc_string(buf);
1174                         free_string(tmp);
1175                 }
1176                 if (!name || !sym) {
1177                         free_string(name);
1178                         return;
1179                 }
1180                 type = get_type(arg);
1181                 str_to_rl(type, value, &rl);
1182                 set_extra_mod(name, sym, alloc_estate_rl(rl));
1183                 free_string(name);
1184                 return;
1185         }
1186
1187         if (arg->type == EXPR_PREOP && arg->op == '&') {
1188                 arg = strip_expr(arg->unop);
1189                 name = expr_to_var_sym(arg, &sym);
1190                 if (!name || !sym)
1191                         goto free;
1192                 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
1193         } else {
1194                 name = expr_to_var_sym(arg, &sym);
1195                 if (!name || !sym)
1196                         goto free;
1197                 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1198         }
1199         type = get_member_type_from_key(arg, key);
1200         if (!type)
1201                 goto free;
1202         str_to_rl(type, value, &rl);
1203         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1204 free:
1205         free_string(name);
1206 }
1207
1208 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1209 {
1210         struct symbol *type;
1211         struct symbol *sym;
1212         char *name;
1213         char member_name[256];
1214         struct range_list *rl;
1215
1216         if (expr->type != EXPR_ASSIGNMENT)
1217                 return;
1218
1219         name = expr_to_var_sym(expr->left, &sym);
1220         if (!name || !sym)
1221                 goto free;
1222         snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1223         type = get_member_type_from_key(expr->left, key);
1224         if (!type)
1225                 return;
1226         str_to_rl(type, value, &rl);
1227         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1228
1229 free:
1230         free_string(name);
1231 }
1232
1233 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1234 {
1235         if (estate_is_whole(state))
1236                 return;
1237
1238         sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1239                         printed_name, state->name);
1240 }
1241
1242 static void match_call_info(struct expression *expr)
1243 {
1244         struct range_list *rl = NULL;
1245         struct expression *arg;
1246         struct symbol *type;
1247         int i = 0;
1248
1249         FOR_EACH_PTR(expr->args, arg) {
1250                 type = get_arg_type(expr->fn, i);
1251
1252                 if (get_implied_rl(arg, &rl))
1253                         rl = cast_rl(type, rl);
1254                 else
1255                         rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1256
1257                 sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1258                 i++;
1259         } END_FOR_EACH_PTR(arg);
1260 }
1261
1262 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1263 {
1264         struct range_list *rl = NULL;
1265         struct smatch_state *state;
1266         struct symbol *type;
1267         char fullname[256];
1268
1269         if (strcmp(key, "*$$") == 0)
1270                 snprintf(fullname, sizeof(fullname), "*%s", name);
1271         else if (strncmp(key, "$$", 2) == 0)
1272                 snprintf(fullname, 256, "%s%s", name, key + 2);
1273         else
1274                 return;
1275
1276         type = get_member_type_from_key(symbol_expression(sym), key);
1277         str_to_rl(type, value, &rl);
1278         state = alloc_estate_rl(rl);
1279         set_state(SMATCH_EXTRA, fullname, sym, state);
1280 }
1281
1282 void register_smatch_extra(int id)
1283 {
1284         my_id = id;
1285
1286         add_merge_hook(my_id, &merge_estates);
1287         add_unmatched_state_hook(my_id, &unmatched_state);
1288         add_hook(&match_function_def, FUNC_DEF_HOOK);
1289         add_hook(&match_declarations, DECLARATION_HOOK);
1290         add_definition_db_callback(set_param_value, PARAM_VALUE);
1291         add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1292         add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1293         add_db_return_states_before(&db_limited_before);
1294         add_db_return_states_callback(LIMITED_VALUE, &db_param_limit_filter);
1295         add_db_return_states_callback(FILTER_VALUE, &db_param_limit_filter);
1296         add_db_return_states_callback(ADDED_VALUE, &db_param_add);
1297         add_db_return_states_after(&db_limited_after);
1298 }
1299
1300 void register_smatch_extra_late(int id)
1301 {
1302         add_hook(&match_dereferences, DEREF_HOOK);
1303         add_hook(&match_pointer_as_array, OP_HOOK);
1304         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1305         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1306         if (option_no_db)
1307                 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1308         add_hook(&match_assign, ASSIGNMENT_HOOK);
1309         add_hook(&unop_expr, OP_HOOK);
1310         add_hook(&asm_expr, ASM_HOOK);
1311
1312         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1313         add_member_info_callback(my_id, struct_member_callback);
1314         add_returned_member_callback(my_id, returned_member_callback);
1315 }