smatch_extra.c

   1 /*
   2  * sparse/smatch_extra.c
   3  *
   4  * Copyright (C) 2008 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * smatch_extra.c is supposed to track the value of every variable.
  12  *
  13  */
  14
  15 #include <stdlib.h>
  16 #include <errno.h>
  17 #ifndef __USE_ISOC99
  18 #define __USE_ISOC99
  19 #endif
  20 #include <limits.h>
  21 #include "parse.h"
  22 #include "smatch.h"
  23 #include "smatch_slist.h"
  24 #include "smatch_extra.h"
  25
  26 static int my_id;
  27
  28 struct string_list *__ignored_macros = NULL;
  29 static int in_warn_on_macro()
  30 {
  31         struct statement *stmt;
  32         char *tmp;
  33         char *macro;
  34
  35         stmt = get_current_statement();
  36         macro = get_macro_name(stmt->pos);
  37         if (!macro)
  38                 return 0;
  39
  40         FOR_EACH_PTR(__ignored_macros, tmp) {
  41                 if (!strcmp(tmp, macro))
  42                         return 1;
  43         } END_FOR_EACH_PTR(tmp);
  44         return 0;
  45 }
  46
  47 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
  48 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
  49 static struct void_fn_list *extra_mod_hooks;
  50 void add_extra_mod_hook(mod_hook *fn)
  51 {
  52         mod_hook **p = malloc(sizeof(mod_hook *));
  53         *p = fn;
  54         add_ptr_list(&extra_mod_hooks, p);
  55 }
  56
  57 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
  58 {
  59         mod_hook **fn;
  60
  61         FOR_EACH_PTR(extra_mod_hooks, fn) {
  62                 (*fn)(name, sym, state);
  63         } END_FOR_EACH_PTR(fn);
  64 }
  65
  66 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
  67 {
  68         if (in_warn_on_macro())
  69                 return NULL;
  70         remove_from_equiv(name, sym);
  71         call_extra_mod_hooks(name, sym, state);
  72         return set_state(SMATCH_EXTRA, name, sym, state);
  73 }
  74
  75 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
  76 {
  77         struct symbol *sym;
  78         char *name;
  79         struct sm_state *ret = NULL;
  80
  81         expr = strip_expr(expr);
  82         name = expr_to_var_sym(expr, &sym);
  83         if (!name || !sym)
  84                 goto free;
  85         ret = set_extra_mod(name, sym, state);
  86 free:
  87         free_string(name);
  88         return ret;
  89 }
  90
  91 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
  92 {
  93         struct relation *rel;
  94         struct smatch_state *orig_state;
  95
  96         orig_state = get_state(SMATCH_EXTRA, name, sym);
  97
  98         if (!estate_related(orig_state)) {
  99                 set_state(SMATCH_EXTRA, name, sym, state);
 100                 return;
 101         }
 102
 103         set_related(state, estate_related(orig_state));
 104         FOR_EACH_PTR(estate_related(orig_state), rel) {
 105                 if (option_debug_related)
 106                         sm_msg("updating related %s to %s", rel->name, state->name);
 107                 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
 108         } END_FOR_EACH_PTR(rel);
 109 }
 110
 111 /*
 112  * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
 113  */
 114 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
 115 {
 116         char *name;
 117         struct symbol *sym;
 118
 119         name = expr_to_var_sym(expr, &sym);
 120         if (!name || !sym)
 121                 goto free;
 122         set_extra_nomod(name, sym, state);
 123 free:
 124         free_string(name);
 125
 126 }
 127
 128 static void set_extra_true_false(const char *name, struct symbol *sym,
 129                         struct smatch_state *true_state,
 130                         struct smatch_state *false_state)
 131 {
 132         struct relation *rel;
 133         struct smatch_state *orig_state;
 134
 135         if (in_warn_on_macro())
 136                 return;
 137
 138         orig_state = get_state(SMATCH_EXTRA, name, sym);
 139
 140         if (!estate_related(orig_state)) {
 141                 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
 142                 return;
 143         }
 144
 145         if (true_state)
 146                 set_related(true_state, estate_related(orig_state));
 147         if (false_state)
 148                 set_related(false_state, estate_related(orig_state));
 149
 150         FOR_EACH_PTR(estate_related(orig_state), rel) {
 151                 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
 152                                 true_state, false_state);
 153         } END_FOR_EACH_PTR(rel);
 154 }
 155
 156 static void set_extra_expr_true_false(struct expression *expr,
 157                 struct smatch_state *true_state,
 158                 struct smatch_state *false_state)
 159 {
 160         char *name;
 161         struct symbol *sym;
 162
 163         expr = strip_expr(expr);
 164         name = expr_to_var_sym(expr, &sym);
 165         if (!name || !sym)
 166                 goto free;
 167         set_extra_true_false(name, sym, true_state, false_state);
 168 free:
 169         free_string(name);
 170 }
 171
 172 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 173 {
 174         struct expression *iter_var;
 175         struct expression *condition;
 176         struct sm_state *sm;
 177         struct smatch_state *estate;
 178         sval_t start;
 179
 180         condition = strip_expr(loop->iterator_pre_condition);
 181         if (!condition)
 182                 return NULL;
 183         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 184                 return NULL;
 185         if (condition->op != SPECIAL_DECREMENT)
 186                 return NULL;
 187
 188         iter_var = condition->unop;
 189         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 190         if (!sm)
 191                 return NULL;
 192         if (sval_cmp_val(estate_min(sm->state), 0) < 0)
 193                 return NULL;
 194         start = estate_max(sm->state);
 195         if  (sval_cmp_val(start, 0) <= 0)
 196                 return NULL;
 197         if (!sval_is_max(start))
 198                 start.value--;
 199
 200         if (condition->type == EXPR_PREOP) {
 201                 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
 202                 if (estate_has_hard_max(sm->state))
 203                         estate_set_hard_max(estate);
 204                 set_extra_expr_mod(iter_var, estate);
 205         }
 206         if (condition->type == EXPR_POSTOP) {
 207                 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
 208                 if (estate_has_hard_max(sm->state))
 209                         estate_set_hard_max(estate);
 210                 set_extra_expr_mod(iter_var, estate);
 211         }
 212         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 213 }
 214
 215 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 216                                                 struct expression *condition)
 217 {
 218         struct expression *iter_var;
 219         struct sm_state *sm;
 220         struct smatch_state *estate;
 221         sval_t start, end, dummy;
 222
 223         iter_var = iter_expr->unop;
 224         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 225         if (!sm)
 226                 return NULL;
 227         if (!estate_get_single_value(sm->state, &start))
 228                 return NULL;
 229         if (!get_implied_max(condition->right, &end))
 230                 end = sval_type_max(get_type(iter_var));
 231
 232         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 233                 return NULL;
 234
 235         switch (condition->op) {
 236         case SPECIAL_NOTEQUAL:
 237         case '<':
 238                 if (!sval_is_min(end))
 239                         end.value--;
 240                 break;
 241         case SPECIAL_LTE:
 242                 break;
 243         default:
 244                 return NULL;
 245         }
 246         if (sval_cmp(end, start) < 0)
 247                 return NULL;
 248         estate = alloc_estate_range(start, end);
 249         if (get_hard_max(condition->right, &dummy))
 250                 estate_set_hard_max(estate);
 251         set_extra_expr_mod(iter_var, estate);
 252         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 253 }
 254
 255 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 256                                                 struct expression *condition)
 257 {
 258         struct expression *iter_var;
 259         struct sm_state *sm;
 260         struct smatch_state *estate;
 261         sval_t start, end;
 262
 263         iter_var = iter_expr->unop;
 264         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 265         if (!sm)
 266                 return NULL;
 267         if (!estate_get_single_value(sm->state, &start))
 268                 return NULL;
 269         if (!get_implied_min(condition->right, &end))
 270                 end = sval_type_min(get_type(iter_var));
 271         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 272                 return NULL;
 273
 274         switch (condition->op) {
 275         case SPECIAL_NOTEQUAL:
 276         case '>':
 277                 if (!sval_is_min(end) && !sval_is_max(end))
 278                         end.value++;
 279                 break;
 280         case SPECIAL_GTE:
 281                 break;
 282         default:
 283                 return NULL;
 284         }
 285         if (sval_cmp(end, start) > 0)
 286                 return NULL;
 287         estate = alloc_estate_range(end, start);
 288         estate_set_hard_max(estate);
 289         set_extra_expr_mod(iter_var, estate);
 290         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 291 }
 292
 293 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 294 {
 295         struct expression *iter_expr;
 296         struct expression *condition;
 297
 298         if (!loop->iterator_post_statement)
 299                 return NULL;
 300         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 301                 return NULL;
 302         iter_expr = loop->iterator_post_statement->expression;
 303         if (!loop->iterator_pre_condition)
 304                 return NULL;
 305         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 306                 return NULL;
 307         condition = loop->iterator_pre_condition;
 308
 309         if (iter_expr->op == SPECIAL_INCREMENT)
 310                 return handle_canonical_for_inc(iter_expr, condition);
 311         if (iter_expr->op == SPECIAL_DECREMENT)
 312                 return handle_canonical_for_dec(iter_expr, condition);
 313         return NULL;
 314 }
 315
 316 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 317 {
 318         struct sm_state *ret;
 319
 320         __push_fake_cur_slist();
 321         if (!loop->iterator_post_statement)
 322                 ret = handle_canonical_while_count_down(loop);
 323         else
 324                 ret = handle_canonical_for_loops(loop);
 325         *slist = __pop_fake_cur_slist();
 326         return ret;
 327 }
 328
 329 int __iterator_unchanged(struct sm_state *sm)
 330 {
 331         if (!sm)
 332                 return 0;
 333         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 334                 return 1;
 335         return 0;
 336 }
 337
 338 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 339 {
 340         sval_t after_value;
 341
 342         /* paranoid checking.  prolly not needed */
 343         condition = strip_expr(condition);
 344         if (!condition)
 345                 return;
 346         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 347                 return;
 348         if (condition->op != SPECIAL_DECREMENT)
 349                 return;
 350         after_value = estate_min(sm->state);
 351         after_value.value--;
 352         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
 353 }
 354
 355 void __extra_pre_loop_hook_after(struct sm_state *sm,
 356                                 struct statement *iterator,
 357                                 struct expression *condition)
 358 {
 359         struct expression *iter_expr;
 360         sval_t limit;
 361         struct smatch_state *state;
 362
 363         if (!iterator) {
 364                 while_count_down_after(sm, condition);
 365                 return;
 366         }
 367
 368         iter_expr = iterator->expression;
 369
 370         if (condition->type != EXPR_COMPARE)
 371                 return;
 372         if (iter_expr->op == SPECIAL_INCREMENT) {
 373                 limit = sval_binop(estate_max(sm->state), '+',
 374                                    sval_type_val(estate_type(sm->state), 1));
 375         } else {
 376                 limit = sval_binop(estate_min(sm->state), '-',
 377                                    sval_type_val(estate_type(sm->state), 1));
 378         }
 379         if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
 380                 if (iter_expr->op == SPECIAL_INCREMENT)
 381                         state = alloc_estate_range(estate_min(sm->state), limit);
 382                 else
 383                         state = alloc_estate_range(limit, estate_max(sm->state));
 384         } else {
 385                 state = alloc_estate_sval(limit);
 386         }
 387         if (!estate_has_hard_max(sm->state))
 388                 estate_clear_hard_max(state);
 389         set_extra_mod(sm->name, sm->sym, state);
 390 }
 391
 392 static struct state_list *unmatched_slist;
 393 static struct smatch_state *unmatched_state(struct sm_state *sm)
 394 {
 395         struct smatch_state *state;
 396
 397         if (unmatched_slist) {
 398                 state = get_state_slist(unmatched_slist, SMATCH_EXTRA, sm->name, sm->sym);
 399                 if (state)
 400                         return state;
 401         }
 402         return alloc_estate_whole(estate_type(sm->state));
 403 }
 404
 405 static void clear_the_pointed_at(struct expression *expr, struct state_list *slist)
 406 {
 407         char *name;
 408         struct symbol *sym;
 409         struct sm_state *tmp;
 410
 411         name = expr_to_var_sym(expr, &sym);
 412         if (!name || !sym)
 413                 goto free;
 414
 415         FOR_EACH_PTR(slist, tmp) {
 416                 if (tmp->name[0] != '*')
 417                         continue;
 418                 if (tmp->sym != sym)
 419                         continue;
 420                 if (strcmp(tmp->name + 1, name) != 0)
 421                         continue;
 422                 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
 423         } END_FOR_EACH_PTR(tmp);
 424
 425 free:
 426         free_string(name);
 427 }
 428
 429 static void match_function_call(struct expression *expr)
 430 {
 431         struct expression *arg;
 432         struct expression *tmp;
 433         struct state_list *slist;
 434
 435         slist = get_all_states(SMATCH_EXTRA);
 436
 437         FOR_EACH_PTR(expr->args, arg) {
 438                 tmp = strip_expr(arg);
 439                 if (tmp->type == EXPR_PREOP && tmp->op == '&')
 440                         set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
 441                 else
 442                         clear_the_pointed_at(tmp, slist);
 443         } END_FOR_EACH_PTR(arg);
 444
 445         free_slist(&slist);
 446 }
 447
 448 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 449 {
 450         if (!one || !two)
 451                 return 0;
 452         if (one->type == SYM_PTR && two->type == SYM_PTR)
 453                 return 1;
 454         return types_equiv(one, two);
 455 }
 456
 457 static int op_remove_assign(int op)
 458 {
 459         switch (op) {
 460         case SPECIAL_ADD_ASSIGN:
 461                 return '+';
 462         case SPECIAL_SUB_ASSIGN:
 463                 return '-';
 464         case SPECIAL_MUL_ASSIGN:
 465                 return '*';
 466         case SPECIAL_DIV_ASSIGN:
 467                 return '/';
 468         case SPECIAL_MOD_ASSIGN:
 469                 return '%';
 470         case SPECIAL_AND_ASSIGN:
 471                 return '&';
 472         case SPECIAL_OR_ASSIGN:
 473                 return '|';
 474         case SPECIAL_XOR_ASSIGN:
 475                 return '^';
 476         case SPECIAL_SHL_ASSIGN:
 477                 return SPECIAL_LEFTSHIFT;
 478         case SPECIAL_SHR_ASSIGN:
 479                 return SPECIAL_RIGHTSHIFT;
 480         default:
 481                 return op;
 482         }
 483 }
 484
 485 static void match_assign(struct expression *expr)
 486 {
 487         struct range_list *rl = NULL;
 488         struct expression *left;
 489         struct expression *right;
 490         struct expression *binop_expr;
 491         struct symbol *right_sym;
 492         struct symbol *left_type;
 493         struct symbol *right_type;
 494         char *right_name = NULL;
 495         struct symbol *sym;
 496         char *name;
 497         sval_t value;
 498         int known;
 499         sval_t right_min, right_max;
 500         sval_t tmp;
 501
 502         left = strip_expr(expr->left);
 503
 504         right = strip_expr(expr->right);
 505         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 506                 right = strip_expr(right->left);
 507
 508         if (is_condition(expr->right))
 509                 return; /* handled in smatch_condition.c */
 510         if (expr->op == '=' && right->type == EXPR_CALL)
 511                 return; /* handled in smatch_function_hooks.c */
 512
 513         name = expr_to_var_sym(left, &sym);
 514         if (!name)
 515                 return;
 516
 517         left_type = get_type(left);
 518         right_type = get_type(right);
 519
 520         right_name = expr_to_var_sym(right, &right_sym);
 521         if (expr->op == '=' && right_name && right_sym &&
 522             types_equiv_or_pointer(left_type, right_type)) {
 523                 set_equiv(left, right);
 524                 goto free;
 525         }
 526
 527         right_min = sval_type_min(right_type);
 528         right_max = sval_type_max(right_type);
 529
 530         known = get_implied_value(right, &value);
 531         switch (expr->op) {
 532         case '=': {
 533                 struct smatch_state *state;
 534
 535                 if (get_implied_rl(right, &rl)) {
 536                         rl = cast_rl(left_type, rl);
 537                         state = alloc_estate_rl(rl);
 538                         if (get_hard_max(right, &tmp))
 539                                 estate_set_hard_max(state);
 540                 } else {
 541                         rl = alloc_whole_rl(right_type);
 542                         rl = cast_rl(left_type, rl);
 543                         state = alloc_estate_rl(rl);
 544                 }
 545                 set_extra_mod(name, sym, state);
 546                 goto free;
 547         }
 548         case SPECIAL_ADD_ASSIGN:
 549                 if (get_implied_min(left, &tmp)) {
 550                         if (known)
 551                                 right_min = sval_binop(tmp, '+', value);
 552                         else
 553                                 right_min = tmp;
 554                 }
 555                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 556                         right_max = sval_binop(tmp, '+', value);
 557                 break;
 558         case SPECIAL_SUB_ASSIGN:
 559                 if (get_implied_max(left, &tmp)) {
 560                         if (known)
 561                                 right_max = sval_binop(tmp, '-', value);
 562                         else
 563                                 right_max = tmp;
 564                 }
 565                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 566                         right_min = sval_binop(tmp, '-', value);
 567                 break;
 568         case SPECIAL_AND_ASSIGN:
 569         case SPECIAL_MOD_ASSIGN:
 570                 binop_expr = binop_expression(expr->left,
 571                                               op_remove_assign(expr->op),
 572                                               expr->right);
 573                 if (get_implied_rl(binop_expr, &rl)) {
 574                         rl = cast_rl(left_type, rl);
 575                         set_extra_mod(name, sym, alloc_estate_rl(rl));
 576                         goto free;
 577                 }
 578         }
 579         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 580                 rl = cast_rl(left_type, alloc_rl(right_min, right_max));
 581         else
 582                 rl = alloc_whole_rl(left_type);
 583         set_extra_mod(name, sym, alloc_estate_rl(rl));
 584 free:
 585         free_string(right_name);
 586         free_string(name);
 587 }
 588
 589 static void reset_struct_members(struct sm_state *sm)
 590 {
 591         if (!estate_rl(sm->state))
 592                 return;
 593         set_extra_mod(sm->name, sm->sym, alloc_estate_whole(estate_type(sm->state)));
 594 }
 595
 596 static struct smatch_state *increment_state(struct smatch_state *state)
 597 {
 598         sval_t min = estate_min(state);
 599         sval_t max = estate_max(state);
 600
 601         if (!estate_rl(state))
 602                 return NULL;
 603
 604         if (inside_loop())
 605                 max = sval_type_max(max.type);
 606
 607         if (!sval_is_min(min) && !sval_is_max(min))
 608                 min.value++;
 609         if (!sval_is_min(max) && !sval_is_max(max))
 610                 max.value++;
 611         return alloc_estate_range(min, max);
 612 }
 613
 614 static struct smatch_state *decrement_state(struct smatch_state *state)
 615 {
 616         sval_t min = estate_min(state);
 617         sval_t max = estate_max(state);
 618
 619         if (!estate_rl(state))
 620                 return NULL;
 621
 622         if (inside_loop())
 623                 min = sval_type_min(min.type);
 624
 625         if (!sval_is_min(min) && !sval_is_max(min))
 626                 min.value--;
 627         if (!sval_is_min(max) && !sval_is_max(max))
 628                 max.value--;
 629         return alloc_estate_range(min, max);
 630 }
 631
 632 static void unop_expr(struct expression *expr)
 633 {
 634         struct smatch_state *state;
 635
 636         if (expr->smatch_flags & Handled)
 637                 return;
 638
 639         switch (expr->op) {
 640         case SPECIAL_INCREMENT:
 641                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 642                 state = increment_state(state);
 643                 if (!state)
 644                         state = alloc_estate_whole(get_type(expr));
 645                 set_extra_expr_mod(expr->unop, state);
 646                 break;
 647         case SPECIAL_DECREMENT:
 648                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 649                 state = decrement_state(state);
 650                 if (!state)
 651                         state = alloc_estate_whole(get_type(expr));
 652                 set_extra_expr_mod(expr->unop, state);
 653                 break;
 654         default:
 655                 return;
 656         }
 657 }
 658
 659 static void asm_expr(struct statement *stmt)
 660 {
 661
 662         struct expression *expr;
 663         int state = 0;
 664
 665         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 666                 switch (state) {
 667                 case 0: /* identifier */
 668                 case 1: /* constraint */
 669                         state++;
 670                         continue;
 671                 case 2: /* expression */
 672                         state = 0;
 673                         set_extra_expr_mod(expr, alloc_estate_whole(get_type(expr)));
 674                         continue;
 675                 }
 676         } END_FOR_EACH_PTR(expr);
 677 }
 678
 679 static void delete_state_tracker(struct tracker *t)
 680 {
 681         remove_from_equiv(t->name, t->sym);
 682         delete_state(t->owner, t->name, t->sym);
 683 }
 684
 685 static void scoped_state_extra(const char *name, struct symbol *sym)
 686 {
 687         struct tracker *t;
 688
 689         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 690         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 691 }
 692
 693 static void match_declarations(struct symbol *sym)
 694 {
 695         const char *name;
 696
 697         if (sym->ident) {
 698                 name = sym->ident->name;
 699                 if (!sym->initializer) {
 700                         set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
 701                         scoped_state_extra(name, sym);
 702                 }
 703         }
 704 }
 705
 706 static void check_dereference(struct expression *expr)
 707 {
 708         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 709 }
 710
 711 static void match_dereferences(struct expression *expr)
 712 {
 713         if (expr->type != EXPR_PREOP)
 714                 return;
 715         check_dereference(expr->unop);
 716 }
 717
 718 static void match_pointer_as_array(struct expression *expr)
 719 {
 720         if (!is_array(expr))
 721                 return;
 722         check_dereference(expr->unop->left);
 723 }
 724
 725 static void set_param_dereferenced(struct expression *arg, char *unused)
 726 {
 727         check_dereference(arg);
 728 }
 729
 730 static void match_function_def(struct symbol *sym)
 731 {
 732         struct symbol *arg;
 733
 734         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 735                 if (!arg->ident)
 736                         continue;
 737                 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
 738         } END_FOR_EACH_PTR(arg);
 739 }
 740
 741 static int match_func_comparison(struct expression *expr)
 742 {
 743         struct expression *left = strip_expr(expr->left);
 744         struct expression *right = strip_expr(expr->right);
 745         sval_t sval;
 746
 747         if (left->type == EXPR_CALL) {
 748                 if (!get_implied_value(right, &sval))
 749                         return 1;
 750                 function_comparison(expr->op, left, sval, 1);
 751                 return 1;
 752         }
 753
 754         if (right->type == EXPR_CALL) {
 755                 if (!get_implied_value(left, &sval))
 756                         return 1;
 757                 function_comparison(expr->op, right, sval, 0);
 758                 return 1;
 759         }
 760
 761         return 0;
 762 }
 763
 764 static sval_t add_one(sval_t sval)
 765 {
 766         sval.value++;
 767         return sval;
 768 }
 769
 770 static sval_t sub_one(sval_t sval)
 771 {
 772         sval.value--;
 773         return sval;
 774 }
 775
 776 static void match_comparison(struct expression *expr)
 777 {
 778         struct expression *left = strip_expr(expr->left);
 779         struct expression *right = strip_expr(expr->right);
 780         struct symbol *type;
 781         struct range_list *left_orig;
 782         struct range_list *left_true;
 783         struct range_list *left_false;
 784         struct range_list *right_orig;
 785         struct range_list *right_true;
 786         struct range_list *right_false;
 787         struct smatch_state *left_true_state;
 788         struct smatch_state *left_false_state;
 789         struct smatch_state *right_true_state;
 790         struct smatch_state *right_false_state;
 791         sval_t min, max, dummy;
 792         int left_postop = 0;
 793         int right_postop = 0;
 794
 795         if (match_func_comparison(expr))
 796                 return;
 797
 798         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 799                 if (left->type == EXPR_POSTOP) {
 800                         left->smatch_flags |= Handled;
 801                         left_postop = left->op;
 802                 }
 803                 left = strip_expr(left->unop);
 804         }
 805         while (left->type == EXPR_ASSIGNMENT)
 806                 left = strip_expr(left->left);
 807
 808         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 809                 if (right->type == EXPR_POSTOP) {
 810                         right->smatch_flags |= Handled;
 811                         right_postop = right->op;
 812                 }
 813                 right = strip_expr(right->unop);
 814         }
 815
 816         type = get_type(expr);
 817         if (!type)
 818                 type = &llong_ctype;
 819
 820         if (get_implied_rl(left, &left_orig)) {
 821                 left_orig = cast_rl(type, left_orig);
 822         } else {
 823                 min = sval_type_min(get_type(left));
 824                 max = sval_type_max(get_type(left));
 825                 left_orig = cast_rl(type, alloc_rl(min, max));
 826         }
 827
 828         if (get_implied_rl(right, &right_orig)) {
 829                 right_orig = cast_rl(type, right_orig);
 830         } else {
 831                 min = sval_type_min(get_type(right));
 832                 max = sval_type_max(get_type(right));
 833                 right_orig = cast_rl(type, alloc_rl(min, max));
 834         }
 835         min = sval_type_min(type);
 836         max = sval_type_max(type);
 837
 838         left_true = clone_rl(left_orig);
 839         left_false = clone_rl(left_orig);
 840         right_true = clone_rl(right_orig);
 841         right_false = clone_rl(right_orig);
 842
 843         switch (expr->op) {
 844         case '<':
 845         case SPECIAL_UNSIGNED_LT:
 846                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 847                 if (!sval_is_min(rl_min(right_orig))) {
 848                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 849                 }
 850
 851                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 852                 if (!sval_is_max(rl_max(left_orig)))
 853                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 854                 break;
 855         case SPECIAL_UNSIGNED_LTE:
 856         case SPECIAL_LTE:
 857                 if (!sval_is_max(rl_max(right_orig)))
 858                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 859                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 860
 861                 if (!sval_is_min(rl_min(left_orig)))
 862                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 863                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 864
 865                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 866                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 867                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 868                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 869                 break;
 870         case SPECIAL_EQUAL:
 871                 if (!sval_is_max(rl_max(right_orig))) {
 872                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 873                 }
 874                 if (!sval_is_min(rl_min(right_orig))) {
 875                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 876                 }
 877                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 878                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 879
 880                 if (!sval_is_max(rl_max(left_orig)))
 881                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 882                 if (!sval_is_min(rl_min(left_orig)))
 883                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 884                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 885                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 886                 break;
 887         case SPECIAL_UNSIGNED_GTE:
 888         case SPECIAL_GTE:
 889                 if (!sval_is_min(rl_min(right_orig)))
 890                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 891                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 892
 893                 if (!sval_is_max(rl_max(left_orig)))
 894                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 895                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 896
 897                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 898                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 899                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 900                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 901                 break;
 902         case '>':
 903         case SPECIAL_UNSIGNED_GT:
 904                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 905                 if (!sval_is_max(rl_max(right_orig)))
 906                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 907
 908                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 909                 if (!sval_is_min(rl_min(left_orig)))
 910                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 911                 break;
 912         case SPECIAL_NOTEQUAL:
 913                 if (!sval_is_max(rl_max(right_orig)))
 914                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 915                 if (!sval_is_min(rl_min(right_orig)))
 916                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 917                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 918                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 919
 920                 if (!sval_is_max(rl_max(left_orig)))
 921                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 922                 if (!sval_is_min(rl_min(left_orig)))
 923                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 924                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 925                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 926                 break;
 927         default:
 928                 return;
 929         }
 930
 931         left_true = rl_truncate_cast(get_type(left), left_true);
 932         left_false = rl_truncate_cast(get_type(left), left_false);
 933         right_true = rl_truncate_cast(get_type(right), right_true);
 934         right_false = rl_truncate_cast(get_type(right), right_false);
 935
 936         left_true_state = alloc_estate_rl(left_true);
 937         left_false_state = alloc_estate_rl(left_false);
 938         right_true_state = alloc_estate_rl(right_true);
 939         right_false_state = alloc_estate_rl(right_false);
 940
 941         switch (expr->op) {
 942         case '<':
 943         case SPECIAL_UNSIGNED_LT:
 944         case SPECIAL_UNSIGNED_LTE:
 945         case SPECIAL_LTE:
 946                 if (get_hard_max(right, &dummy))
 947                         estate_set_hard_max(left_true_state);
 948                 if (get_hard_max(left, &dummy))
 949                         estate_set_hard_max(right_false_state);
 950                 break;
 951         case '>':
 952         case SPECIAL_UNSIGNED_GT:
 953         case SPECIAL_UNSIGNED_GTE:
 954         case SPECIAL_GTE:
 955                 if (get_hard_max(left, &dummy))
 956                         estate_set_hard_max(right_true_state);
 957                 if (get_hard_max(right, &dummy))
 958                         estate_set_hard_max(left_false_state);
 959                 break;
 960         }
 961
 962         if (get_hard_max(left, &dummy)) {
 963                 estate_set_hard_max(left_true_state);
 964                 estate_set_hard_max(left_false_state);
 965         }
 966         if (get_hard_max(right, &dummy)) {
 967                 estate_set_hard_max(right_true_state);
 968                 estate_set_hard_max(right_false_state);
 969         }
 970
 971         if (left_postop == SPECIAL_INCREMENT) {
 972                 left_true_state = increment_state(left_true_state);
 973                 left_false_state = increment_state(left_false_state);
 974         }
 975         if (left_postop == SPECIAL_DECREMENT) {
 976                 left_true_state = decrement_state(left_true_state);
 977                 left_false_state = decrement_state(left_false_state);
 978         }
 979         if (right_postop == SPECIAL_INCREMENT) {
 980                 right_true_state = increment_state(right_true_state);
 981                 right_false_state = increment_state(right_false_state);
 982         }
 983         if (right_postop == SPECIAL_DECREMENT) {
 984                 right_true_state = decrement_state(right_true_state);
 985                 right_false_state = decrement_state(right_false_state);
 986         }
 987
 988         set_extra_expr_true_false(left, left_true_state, left_false_state);
 989         set_extra_expr_true_false(right, right_true_state, right_false_state);
 990 }
 991
 992 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 993 void __extra_match_condition(struct expression *expr)
 994 {
 995         struct symbol *sym;
 996         char *name;
 997         struct smatch_state *pre_state;
 998         struct smatch_state *true_state;
 999         struct smatch_state *false_state;
1000
1001         expr = strip_expr(expr);
1002         switch (expr->type) {
1003         case EXPR_CALL:
1004                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
1005                 return;
1006         case EXPR_PREOP:
1007         case EXPR_SYMBOL:
1008         case EXPR_DEREF: {
1009                 sval_t zero;
1010
1011                 zero = sval_blank(expr);
1012                 zero.value = 0;
1013
1014                 name = expr_to_var_sym(expr, &sym);
1015                 if (!name)
1016                         return;
1017                 pre_state = get_state(my_id, name, sym);
1018                 true_state = estate_filter_sval(pre_state, zero);
1019                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1020                         false_state = alloc_estate_sval(zero);
1021                 else
1022                         false_state = alloc_estate_empty();
1023                 set_extra_true_false(name, sym, true_state, false_state);
1024                 free_string(name);
1025                 return;
1026         }
1027         case EXPR_COMPARE:
1028                 match_comparison(expr);
1029                 return;
1030         case EXPR_ASSIGNMENT:
1031                 __extra_match_condition(expr->left);
1032                 return;
1033         }
1034 }
1035
1036 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1037 int implied_not_equal(struct expression *expr, long long val)
1038 {
1039         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1040 }
1041
1042 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1043 {
1044         if (estate_is_whole(state))
1045                 return;
1046         sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1047 }
1048
1049 static void db_limited_before(void)
1050 {
1051         unmatched_slist = clone_slist(__get_cur_slist());
1052 }
1053
1054 static void db_limited_after(void)
1055 {
1056         free_slist(&unmatched_slist);
1057 }
1058
1059 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value)
1060 {
1061         struct expression *arg;
1062         char *name;
1063         struct symbol *sym;
1064         struct sm_state *sm;
1065         struct symbol *type;
1066         struct range_list *rl;
1067         struct range_list *limit;
1068         struct range_list *new;
1069
1070         while (expr->type == EXPR_ASSIGNMENT)
1071                 expr = strip_expr(expr->right);
1072         if (expr->type != EXPR_CALL)
1073                 return;
1074
1075         arg = get_argument_from_call_expr(expr->args, param);
1076         if (!arg)
1077                 return;
1078
1079         name = get_variable_from_key(arg, key, &sym);
1080         if (!name || !sym)
1081                 goto free;
1082
1083         sm = get_sm_state(SMATCH_EXTRA, name, sym);
1084         type = get_member_type_from_key(arg, key);
1085         if (sm)
1086                 rl = estate_rl(sm->state);
1087         else
1088                 rl = alloc_whole_rl(type);
1089
1090         str_to_rl(type, value, &limit);
1091         new = rl_intersection(rl, limit);
1092
1093         /* We want to preserve the implications here */
1094         if (sm && rl_equiv(estate_rl(sm->state), new))
1095                 __set_sm(sm);
1096         else
1097                 set_extra_nomod(name, sym, alloc_estate_rl(new));
1098
1099 free:
1100         free_string(name);
1101 }
1102
1103 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1104 {
1105         struct expression *arg;
1106         char *name;
1107         struct symbol *sym;
1108         struct symbol *type;
1109         struct smatch_state *state;
1110         struct range_list *added = NULL;
1111         struct range_list *new;
1112
1113         while (expr->type == EXPR_ASSIGNMENT)
1114                 expr = strip_expr(expr->right);
1115         if (expr->type != EXPR_CALL)
1116                 return;
1117
1118         arg = get_argument_from_call_expr(expr->args, param);
1119         if (!arg)
1120                 return;
1121         name = get_variable_from_key(arg, key, &sym);
1122         if (!name || !sym)
1123                 goto free;
1124
1125         type = get_member_type_from_key(arg, key);
1126         state = get_state(SMATCH_EXTRA, name, sym);
1127         if (state) {
1128                 str_to_rl(type, value, &added);
1129                 new = rl_union(estate_rl(state), added);
1130         } else {
1131                 new = alloc_whole_rl(type);
1132         }
1133
1134         set_extra_mod(name, sym, alloc_estate_rl(new));
1135 free:
1136         free_string(name);
1137 }
1138
1139 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
1140 {
1141         struct expression *arg;
1142         struct symbol *type;
1143         struct range_list *rl;
1144         char member_name[256];
1145         char *name;
1146         struct symbol *sym;
1147
1148         while (expr->type == EXPR_ASSIGNMENT)
1149                 expr = strip_expr(expr->right);
1150         if (expr->type != EXPR_CALL)
1151                 return;
1152         arg = get_argument_from_call_expr(expr->args, param);
1153         arg = strip_expr(arg);
1154         if (!arg)
1155                 return;
1156
1157         if (strcmp(key, "*$$") == 0) {
1158                 struct symbol *sym;
1159                 char buf[256];
1160                 char *name;
1161
1162                 if (arg->type == EXPR_PREOP && arg->op == '&') {
1163                         arg = strip_expr(arg->unop);
1164                         name = expr_to_var_sym(arg, &sym);
1165                 } else {
1166                         char *tmp = expr_to_var_sym(arg, &sym);
1167
1168                         if (!tmp)
1169                                 return;
1170                         snprintf(buf, sizeof(buf), "*%s", tmp);
1171                         name = alloc_string(buf);
1172                         free_string(tmp);
1173                 }
1174                 if (!name || !sym) {
1175                         free_string(name);
1176                         return;
1177                 }
1178                 type = get_type(arg);
1179                 str_to_rl(type, value, &rl);
1180                 set_extra_mod(name, sym, alloc_estate_rl(rl));
1181                 free_string(name);
1182                 return;
1183         }
1184
1185         if (arg->type == EXPR_PREOP && arg->op == '&') {
1186                 arg = strip_expr(arg->unop);
1187                 name = expr_to_var_sym(arg, &sym);
1188                 if (!name || !sym)
1189                         goto free;
1190                 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
1191         } else {
1192                 name = expr_to_var_sym(arg, &sym);
1193                 if (!name || !sym)
1194                         goto free;
1195                 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1196         }
1197         type = get_member_type_from_key(arg, key);
1198         if (!type)
1199                 goto free;
1200         str_to_rl(type, value, &rl);
1201         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1202 free:
1203         free_string(name);
1204 }
1205
1206 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1207 {
1208         struct symbol *type;
1209         struct symbol *sym;
1210         char *name;
1211         char member_name[256];
1212         struct range_list *rl;
1213
1214         if (expr->type != EXPR_ASSIGNMENT)
1215                 return;
1216
1217         name = expr_to_var_sym(expr->left, &sym);
1218         if (!name || !sym)
1219                 goto free;
1220         snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1221         type = get_member_type_from_key(expr->left, key);
1222         if (!type)
1223                 return;
1224         str_to_rl(type, value, &rl);
1225         set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1226
1227 free:
1228         free_string(name);
1229 }
1230
1231 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1232 {
1233         if (estate_is_whole(state))
1234                 return;
1235
1236         sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1237                         printed_name, state->name);
1238 }
1239
1240 static void match_call_info(struct expression *expr)
1241 {
1242         struct range_list *rl = NULL;
1243         struct expression *arg;
1244         struct symbol *type;
1245         int i = 0;
1246
1247         FOR_EACH_PTR(expr->args, arg) {
1248                 type = get_arg_type(expr->fn, i);
1249
1250                 if (get_implied_rl(arg, &rl))
1251                         rl = cast_rl(type, rl);
1252                 else
1253                         rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1254
1255                 sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1256                 i++;
1257         } END_FOR_EACH_PTR(arg);
1258 }
1259
1260 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1261 {
1262         struct range_list *rl = NULL;
1263         struct smatch_state *state;
1264         struct symbol *type;
1265         char fullname[256];
1266
1267         if (strcmp(key, "*$$") == 0)
1268                 snprintf(fullname, sizeof(fullname), "*%s", name);
1269         else if (strncmp(key, "$$", 2) == 0)
1270                 snprintf(fullname, 256, "%s%s", name, key + 2);
1271         else
1272                 return;
1273
1274         type = get_member_type_from_key(symbol_expression(sym), key);
1275         str_to_rl(type, value, &rl);
1276         state = alloc_estate_rl(rl);
1277         set_state(SMATCH_EXTRA, fullname, sym, state);
1278 }
1279
1280 void register_smatch_extra(int id)
1281 {
1282         my_id = id;
1283
1284         add_merge_hook(my_id, &merge_estates);
1285         add_unmatched_state_hook(my_id, &unmatched_state);
1286         add_hook(&match_function_def, FUNC_DEF_HOOK);
1287         add_hook(&match_declarations, DECLARATION_HOOK);
1288         add_definition_db_callback(set_param_value, PARAM_VALUE);
1289         add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1290         add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1291         add_db_return_states_before(&db_limited_before);
1292         add_db_return_states_callback(LIMITED_VALUE, &db_param_limit_filter);
1293         add_db_return_states_callback(FILTER_VALUE, &db_param_limit_filter);
1294         add_db_return_states_callback(ADDED_VALUE, &db_param_add);
1295         add_db_return_states_after(&db_limited_after);
1296 }
1297
1298 void register_smatch_extra_late(int id)
1299 {
1300         add_hook(&match_dereferences, DEREF_HOOK);
1301         add_hook(&match_pointer_as_array, OP_HOOK);
1302         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1303         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1304         if (option_no_db)
1305                 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1306         add_hook(&match_assign, ASSIGNMENT_HOOK);
1307         add_hook(&unop_expr, OP_HOOK);
1308         add_hook(&asm_expr, ASM_HOOK);
1309
1310         add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1311         add_member_info_callback(my_id, struct_member_callback);
1312         add_returned_member_callback(my_id, returned_member_callback);
1313 }