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         struct symbol *type;
 666         int state = 0;
 667
 668         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 669                 switch (state) {
 670                 case 0: /* identifier */
 671                 case 1: /* constraint */
 672                         state++;
 673                         continue;
 674                 case 2: /* expression */
 675                         state = 0;
 676                         type = get_type(strip_expr(expr));
 677                         set_extra_expr_mod(expr, alloc_estate_whole(type));
 678                         continue;
 679                 }
 680         } END_FOR_EACH_PTR(expr);
 681 }
 682
 683 static void delete_state_tracker(struct tracker *t)
 684 {
 685         remove_from_equiv(t->name, t->sym);
 686         delete_state(t->owner, t->name, t->sym);
 687 }
 688
 689 static void scoped_state_extra(const char *name, struct symbol *sym)
 690 {
 691         struct tracker *t;
 692
 693         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 694         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 695 }
 696
 697 static void match_declarations(struct symbol *sym)
 698 {
 699         const char *name;
 700
 701         if (sym->ident) {
 702                 name = sym->ident->name;
 703                 if (!sym->initializer) {
 704                         set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
 705                         scoped_state_extra(name, sym);
 706                 }
 707         }
 708 }
 709
 710 static void check_dereference(struct expression *expr)
 711 {
 712         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 713 }
 714
 715 static void match_dereferences(struct expression *expr)
 716 {
 717         if (expr->type != EXPR_PREOP)
 718                 return;
 719         check_dereference(expr->unop);
 720 }
 721
 722 static void match_pointer_as_array(struct expression *expr)
 723 {
 724         if (!is_array(expr))
 725                 return;
 726         check_dereference(expr->unop->left);
 727 }
 728
 729 static void set_param_dereferenced(struct expression *arg, char *unused)
 730 {
 731         check_dereference(arg);
 732 }
 733
 734 static void match_function_def(struct symbol *sym)
 735 {
 736         struct symbol *arg;
 737
 738         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 739                 if (!arg->ident)
 740                         continue;
 741                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 742         } END_FOR_EACH_PTR(arg);
 743 }
 744
 745 static int match_func_comparison(struct expression *expr)
 746 {
 747         struct expression *left = strip_expr(expr->left);
 748         struct expression *right = strip_expr(expr->right);
 749         sval_t sval;
 750
 751         if (left->type == EXPR_CALL) {
 752                 if (!get_implied_value(right, &sval))
 753                         return 1;
 754                 function_comparison(expr->op, left, sval, 1);
 755                 return 1;
 756         }
 757
 758         if (right->type == EXPR_CALL) {
 759                 if (!get_implied_value(left, &sval))
 760                         return 1;
 761                 function_comparison(expr->op, right, sval, 0);
 762                 return 1;
 763         }
 764
 765         return 0;
 766 }
 767
 768 static sval_t add_one(sval_t sval)
 769 {
 770         sval.value++;
 771         return sval;
 772 }
 773
 774 static sval_t sub_one(sval_t sval)
 775 {
 776         sval.value--;
 777         return sval;
 778 }
 779
 780 static void match_comparison(struct expression *expr)
 781 {
 782         struct expression *left = strip_expr(expr->left);
 783         struct expression *right = strip_expr(expr->right);
 784         struct symbol *type;
 785         struct range_list *left_orig;
 786         struct range_list *left_true;
 787         struct range_list *left_false;
 788         struct range_list *right_orig;
 789         struct range_list *right_true;
 790         struct range_list *right_false;
 791         struct smatch_state *left_true_state;
 792         struct smatch_state *left_false_state;
 793         struct smatch_state *right_true_state;
 794         struct smatch_state *right_false_state;
 795         sval_t min, max, dummy;
 796         int left_postop = 0;
 797         int right_postop = 0;
 798
 799         if (match_func_comparison(expr))
 800                 return;
 801
 802         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 803                 if (left->type == EXPR_POSTOP) {
 804                         left->smatch_flags |= Handled;
 805                         left_postop = left->op;
 806                 }
 807                 left = strip_expr(left->unop);
 808         }
 809         while (left->type == EXPR_ASSIGNMENT)
 810                 left = strip_expr(left->left);
 811
 812         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 813                 if (right->type == EXPR_POSTOP) {
 814                         right->smatch_flags |= Handled;
 815                         right_postop = right->op;
 816                 }
 817                 right = strip_expr(right->unop);
 818         }
 819
 820         type = get_type(expr);
 821         if (!type)
 822                 type = &llong_ctype;
 823
 824         if (get_implied_rl(left, &left_orig)) {
 825                 left_orig = cast_rl(type, left_orig);
 826         } else {
 827                 min = sval_type_min(get_type(left));
 828                 max = sval_type_max(get_type(left));
 829                 left_orig = cast_rl(type, alloc_rl(min, max));
 830         }
 831
 832         if (get_implied_rl(right, &right_orig)) {
 833                 right_orig = cast_rl(type, right_orig);
 834         } else {
 835                 min = sval_type_min(get_type(right));
 836                 max = sval_type_max(get_type(right));
 837                 right_orig = cast_rl(type, alloc_rl(min, max));
 838         }
 839         min = sval_type_min(type);
 840         max = sval_type_max(type);
 841
 842         left_true = clone_rl(left_orig);
 843         left_false = clone_rl(left_orig);
 844         right_true = clone_rl(right_orig);
 845         right_false = clone_rl(right_orig);
 846
 847         switch (expr->op) {
 848         case '<':
 849         case SPECIAL_UNSIGNED_LT:
 850                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 851                 if (!sval_is_min(rl_min(right_orig))) {
 852                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 853                 }
 854
 855                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 856                 if (!sval_is_max(rl_max(left_orig)))
 857                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 858                 break;
 859         case SPECIAL_UNSIGNED_LTE:
 860         case SPECIAL_LTE:
 861                 if (!sval_is_max(rl_max(right_orig)))
 862                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 863                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 864
 865                 if (!sval_is_min(rl_min(left_orig)))
 866                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 867                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 868
 869                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 870                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 871                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 872                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 873                 break;
 874         case SPECIAL_EQUAL:
 875                 if (!sval_is_max(rl_max(right_orig))) {
 876                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 877                 }
 878                 if (!sval_is_min(rl_min(right_orig))) {
 879                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 880                 }
 881                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 882                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 883
 884                 if (!sval_is_max(rl_max(left_orig)))
 885                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 886                 if (!sval_is_min(rl_min(left_orig)))
 887                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 888                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 889                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 890                 break;
 891         case SPECIAL_UNSIGNED_GTE:
 892         case SPECIAL_GTE:
 893                 if (!sval_is_min(rl_min(right_orig)))
 894                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 895                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 896
 897                 if (!sval_is_max(rl_max(left_orig)))
 898                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 899                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 900
 901                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 902                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 903                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 904                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 905                 break;
 906         case '>':
 907         case SPECIAL_UNSIGNED_GT:
 908                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 909                 if (!sval_is_max(rl_max(right_orig)))
 910                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 911
 912                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 913                 if (!sval_is_min(rl_min(left_orig)))
 914                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 915                 break;
 916         case SPECIAL_NOTEQUAL:
 917                 if (!sval_is_max(rl_max(right_orig)))
 918                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 919                 if (!sval_is_min(rl_min(right_orig)))
 920                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 921                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 922                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 923
 924                 if (!sval_is_max(rl_max(left_orig)))
 925                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 926                 if (!sval_is_min(rl_min(left_orig)))
 927                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 928                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 929                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 930                 break;
 931         default:
 932                 return;
 933         }
 934
 935         left_true = rl_truncate_cast(get_type(left), left_true);
 936         left_false = rl_truncate_cast(get_type(left), left_false);
 937         right_true = rl_truncate_cast(get_type(right), right_true);
 938         right_false = rl_truncate_cast(get_type(right), right_false);
 939
 940         left_true_state = alloc_estate_rl(left_true);
 941         left_false_state = alloc_estate_rl(left_false);
 942         right_true_state = alloc_estate_rl(right_true);
 943         right_false_state = alloc_estate_rl(right_false);
 944
 945         switch (expr->op) {
 946         case '<':
 947         case SPECIAL_UNSIGNED_LT:
 948         case SPECIAL_UNSIGNED_LTE:
 949         case SPECIAL_LTE:
 950                 if (get_hard_max(right, &dummy))
 951                         estate_set_hard_max(left_true_state);
 952                 if (get_hard_max(left, &dummy))
 953                         estate_set_hard_max(right_false_state);
 954                 break;
 955         case '>':
 956         case SPECIAL_UNSIGNED_GT:
 957         case SPECIAL_UNSIGNED_GTE:
 958         case SPECIAL_GTE:
 959                 if (get_hard_max(left, &dummy))
 960                         estate_set_hard_max(right_true_state);
 961                 if (get_hard_max(right, &dummy))
 962                         estate_set_hard_max(left_false_state);
 963                 break;
 964         }
 965
 966         if (get_hard_max(left, &dummy)) {
 967                 estate_set_hard_max(left_true_state);
 968                 estate_set_hard_max(left_false_state);
 969         }
 970         if (get_hard_max(right, &dummy)) {
 971                 estate_set_hard_max(right_true_state);
 972                 estate_set_hard_max(right_false_state);
 973         }
 974
 975         if (left_postop == SPECIAL_INCREMENT) {
 976                 left_true_state = increment_state(left_true_state);
 977                 left_false_state = increment_state(left_false_state);
 978         }
 979         if (left_postop == SPECIAL_DECREMENT) {
 980                 left_true_state = decrement_state(left_true_state);
 981                 left_false_state = decrement_state(left_false_state);
 982         }
 983         if (right_postop == SPECIAL_INCREMENT) {
 984                 right_true_state = increment_state(right_true_state);
 985                 right_false_state = increment_state(right_false_state);
 986         }
 987         if (right_postop == SPECIAL_DECREMENT) {
 988                 right_true_state = decrement_state(right_true_state);
 989                 right_false_state = decrement_state(right_false_state);
 990         }
 991
 992         set_extra_expr_true_false(left, left_true_state, left_false_state);
 993         set_extra_expr_true_false(right, right_true_state, right_false_state);
 994 }
 995
 996 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 997 void __extra_match_condition(struct expression *expr)
 998 {
 999         struct symbol *sym;
1000         char *name;
1001         struct smatch_state *pre_state;
1002         struct smatch_state *true_state;
1003         struct smatch_state *false_state;
1004
1005         expr = strip_expr(expr);
1006         switch (expr->type) {
1007         case EXPR_CALL:
1008                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
1009                 return;
1010         case EXPR_PREOP:
1011         case EXPR_SYMBOL:
1012         case EXPR_DEREF: {
1013                 sval_t zero;
1014
1015                 zero = sval_blank(expr);
1016                 zero.value = 0;
1017
1018                 name = expr_to_var_sym(expr, &sym);
1019                 if (!name)
1020                         return;
1021                 pre_state = get_state(my_id, name, sym);
1022                 true_state = estate_filter_sval(pre_state, zero);
1023                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1024                         false_state = alloc_estate_sval(zero);
1025                 else
1026                         false_state = alloc_estate_empty();
1027                 set_extra_true_false(name, sym, true_state, false_state);
1028                 free_string(name);
1029                 return;
1030         }
1031         case EXPR_COMPARE:
1032                 match_comparison(expr);
1033                 return;
1034         case EXPR_ASSIGNMENT:
1035                 __extra_match_condition(expr->left);
1036                 return;
1037         }
1038 }
1039
1040 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1041 int implied_not_equal(struct expression *expr, long long val)
1042 {
1043         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1044 }
1045
1046 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1047 {
1048         if (estate_is_whole(state))
1049                 return;
1050         sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1051 }
1052
1053 static void db_limited_before(void)
1054 {
1055         unmatched_slist = clone_slist(__get_cur_slist());
1056 }
1057
1058 static void db_limited_after(void)
1059 {
1060         free_slist(&unmatched_slist);
1061 }
1062
1063 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value)
1064 {
1065         struct expression *arg;
1066         char *name;
1067         struct symbol *sym;
1068         struct sm_state *sm;
1069         struct symbol *type;
1070         struct range_list *rl;
1071         struct range_list *limit;
1072         struct range_list *new;
1073
1074         while (expr->type == EXPR_ASSIGNMENT)
1075                 expr = strip_expr(expr->right);
1076         if (expr->type != EXPR_CALL)
1077                 return;
1078
1079         arg = get_argument_from_call_expr(expr->args, param);
1080         if (!arg)
1081                 return;
1082
1083         name = get_variable_from_key(arg, key, &sym);
1084         if (!name || !sym)
1085                 goto free;
1086
1087         sm = get_sm_state(SMATCH_EXTRA, name, sym);
1088         type = get_member_type_from_key(arg, key);
1089         if (sm)
1090                 rl = estate_rl(sm->state);
1091         else
1092                 rl = alloc_whole_rl(type);
1093
1094         str_to_rl(type, value, &limit);
1095         new = rl_intersection(rl, limit);
1096
1097         /* We want to preserve the implications here */
1098         if (sm && rl_equiv(estate_rl(sm->state), new))
1099                 __set_sm(sm);
1100         else
1101                 set_extra_nomod(name, sym, alloc_estate_rl(new));
1102
1103 free:
1104         free_string(name);
1105 }
1106
1107 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1108 {
1109         struct expression *arg;
1110         char *name;
1111         struct symbol *sym;
1112         struct symbol *type;
1113         struct smatch_state *state;
1114         struct range_list *added = NULL;
1115         struct range_list *new;
1116
1117         while (expr->type == EXPR_ASSIGNMENT)
1118                 expr = strip_expr(expr->right);
1119         if (expr->type != EXPR_CALL)
1120                 return;
1121
1122         arg = get_argument_from_call_expr(expr->args, param);
1123         if (!arg)
1124                 return;
1125         name = get_variable_from_key(arg, key, &sym);
1126         if (!name || !sym)
1127                 goto free;
1128
1129         type = get_member_type_from_key(arg, key);
1130         state = get_state(SMATCH_EXTRA, name, sym);
1131         if (state) {
1132                 str_to_rl(type, value, &added);
1133                 new = rl_union(estate_rl(state), added);
1134         } else {
1135                 new = alloc_whole_rl(type);
1136         }
1137
1138         set_extra_mod(name, sym, alloc_estate_rl(new));
1139 free:
1140         free_string(name);
1141 }
1142
1143 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
1144 {
1145         struct expression *arg;
1146         struct symbol *type;
1147         struct range_list *rl;
1148         char member_name[256];
1149         char *name;
1150         struct symbol *sym;
1151
1152         while (expr->type == EXPR_ASSIGNMENT)
1153                 expr = strip_expr(expr->right);
1154         if (expr->type != EXPR_CALL)
1155                 return;
1156         arg = get_argument_from_call_expr(expr->args, param);
1157         arg = strip_expr(arg);
1158         if (!arg)
1159                 return;
1160
1161         if (strcmp(key, "*$$") == 0) {
1162                 struct symbol *sym;
1163                 char buf[256];
1164                 char *name;
1165
1166                 if (arg->type == EXPR_PREOP && arg->op == '&') {
1167                         arg = strip_expr(arg->unop);
1168                         name = expr_to_var_sym(arg, &sym);
1169                 } else {
1170                         char *tmp = expr_to_var_sym(arg, &sym);
1171
1172                         if (!tmp)
1173                                 return;
1174                         snprintf(buf, sizeof(buf), "*%s", tmp);
1175                         name = alloc_string(buf);
1176                         free_string(tmp);
1177                 }
1178                 if (!name || !sym) {
1179                         free_string(name);
1180                         return;
1181                 }
1182                 type = get_type(arg);
1183                 str_to_rl(type, value, &rl);
1184                 set_extra_mod(name, sym, alloc_estate_rl(rl));
1185                 free_string(name);
1186                 return;
1187         }
1188
1189         if (arg->type == EXPR_PREOP && arg->op == '&') {
1190                 arg = strip_expr(arg->unop);
1191                 name = expr_to_var_sym(arg, &sym);
1192                 if (!name || !sym)
1193                         goto free;
1194                 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
1195         } else {
1196                 name = expr_to_var_sym(arg, &sym);
1197                 if (!name || !sym)
1198                         goto free;
1199                 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1200         }
1201         type = get_member_type_from_key(arg, key);
1202         if (!type)
1203                 goto free;
1204         str_to_rl(type, value, &rl);
1205         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1206 free:
1207         free_string(name);
1208 }
1209
1210 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1211 {
1212         struct symbol *type;
1213         struct symbol *sym;
1214         char *name;
1215         char member_name[256];
1216         struct range_list *rl;
1217
1218         if (expr->type != EXPR_ASSIGNMENT)
1219                 return;
1220
1221         name = expr_to_var_sym(expr->left, &sym);
1222         if (!name || !sym)
1223                 goto free;
1224         snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1225         type = get_member_type_from_key(expr->left, key);
1226         if (!type)
1227                 return;
1228         str_to_rl(type, value, &rl);
1229         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1230
1231 free:
1232         free_string(name);
1233 }
1234
1235 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1236 {
1237         if (estate_is_whole(state))
1238                 return;
1239
1240         sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1241                         printed_name, state->name);
1242 }
1243
1244 static void match_call_info(struct expression *expr)
1245 {
1246         struct range_list *rl = NULL;
1247         struct expression *arg;
1248         struct symbol *type;
1249         int i = 0;
1250
1251         FOR_EACH_PTR(expr->args, arg) {
1252                 type = get_arg_type(expr->fn, i);
1253
1254                 if (get_implied_rl(arg, &rl))
1255                         rl = cast_rl(type, rl);
1256                 else
1257                         rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1258
1259                 sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1260                 i++;
1261         } END_FOR_EACH_PTR(arg);
1262 }
1263
1264 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1265 {
1266         struct range_list *rl = NULL;
1267         struct smatch_state *state;
1268         struct symbol *type;
1269         char fullname[256];
1270
1271         if (strcmp(key, "*$$") == 0)
1272                 snprintf(fullname, sizeof(fullname), "*%s", name);
1273         else if (strncmp(key, "$$", 2) == 0)
1274                 snprintf(fullname, 256, "%s%s", name, key + 2);
1275         else
1276                 return;
1277
1278         type = get_member_type_from_key(symbol_expression(sym), key);
1279         str_to_rl(type, value, &rl);
1280         state = alloc_estate_rl(rl);
1281         set_state(SMATCH_EXTRA, fullname, sym, state);
1282 }
1283
1284 void register_smatch_extra(int id)
1285 {
1286         my_id = id;
1287
1288         add_merge_hook(my_id, &merge_estates);
1289         add_unmatched_state_hook(my_id, &unmatched_state);
1290         add_hook(&match_function_def, FUNC_DEF_HOOK);
1291         add_hook(&match_declarations, DECLARATION_HOOK);
1292         add_definition_db_callback(set_param_value, PARAM_VALUE);
1293         add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1294         add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1295         add_db_return_states_before(&db_limited_before);
1296         add_db_return_states_callback(LIMITED_VALUE, &db_param_limit_filter);
1297         add_db_return_states_callback(FILTER_VALUE, &db_param_limit_filter);
1298         add_db_return_states_callback(ADDED_VALUE, &db_param_add);
1299         add_db_return_states_after(&db_limited_after);
1300 }
1301
1302 void register_smatch_extra_late(int id)
1303 {
1304         add_hook(&match_dereferences, DEREF_HOOK);
1305         add_hook(&match_pointer_as_array, OP_HOOK);
1306         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1307         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1308         if (option_no_db)
1309                 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1310         add_hook(&match_assign, ASSIGNMENT_HOOK);
1311         add_hook(&unop_expr, OP_HOOK);
1312         add_hook(&asm_expr, ASM_HOOK);
1313
1314         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1315         add_member_info_callback(my_id, struct_member_callback);
1316         add_returned_member_callback(my_id, returned_member_callback);
1317 }