smatch_extra.c

   1 /*
   2  * sparse/smatch_extra.c
   3  *
   4  * Copyright (C) 2008 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 /*
  11  * smatch_extra.c is supposed to track the value of every variable.
  12  *
  13  */
  14
  15 #include <stdlib.h>
  16 #include <errno.h>
  17 #ifndef __USE_ISOC99
  18 #define __USE_ISOC99
  19 #endif
  20 #include <limits.h>
  21 #include "parse.h"
  22 #include "smatch.h"
  23 #include "smatch_slist.h"
  24 #include "smatch_extra.h"
  25
  26 static int my_id;
  27
  28 struct string_list *__ignored_macros = NULL;
  29 static int in_warn_on_macro()
  30 {
  31         struct statement *stmt;
  32         char *tmp;
  33         char *macro;
  34
  35         stmt = get_current_statement();
  36         macro = get_macro_name(stmt->pos);
  37         if (!macro)
  38                 return 0;
  39
  40         FOR_EACH_PTR(__ignored_macros, tmp) {
  41                 if (!strcmp(tmp, macro))
  42                         return 1;
  43         } END_FOR_EACH_PTR(tmp);
  44         return 0;
  45 }
  46
  47 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
  48 {
  49         if (in_warn_on_macro())
  50                 return NULL;
  51         remove_from_equiv(name, sym);
  52         return set_state(SMATCH_EXTRA, name, sym, state);
  53 }
  54
  55 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
  56 {
  57         if (in_warn_on_macro())
  58                 return NULL;
  59         remove_from_equiv_expr(expr);
  60         return set_state_expr(SMATCH_EXTRA, expr, state);
  61 }
  62
  63 /*
  64  * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
  65  */
  66 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
  67 {
  68         struct relation *rel;
  69         struct smatch_state *orig_state;
  70
  71         orig_state = get_state_expr(SMATCH_EXTRA, expr);
  72
  73         if (!estate_related(orig_state)) {
  74                 set_state_expr(SMATCH_EXTRA, expr, state);
  75                 return;
  76         }
  77
  78         set_related(&state, estate_related(orig_state));
  79         FOR_EACH_PTR(estate_related(orig_state), rel) {
  80                 if (option_debug_related)
  81                         sm_msg("updating related %s to %s", rel->name, state->name);
  82                 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
  83         } END_FOR_EACH_PTR(rel);
  84 }
  85
  86 static void set_extra_true_false(const char *name, struct symbol *sym,
  87                         struct smatch_state *true_state,
  88                         struct smatch_state *false_state)
  89 {
  90         struct relation *rel;
  91         struct smatch_state *orig_state;
  92
  93         if (in_warn_on_macro())
  94                 return;
  95
  96         orig_state = get_state(SMATCH_EXTRA, name, sym);
  97
  98         if (!estate_related(orig_state)) {
  99                 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
 100                 return;
 101         }
 102
 103         if (true_state)
 104                 set_related(&true_state, estate_related(orig_state));
 105         if (false_state)
 106                 set_related(&false_state, estate_related(orig_state));
 107
 108         FOR_EACH_PTR(estate_related(orig_state), rel) {
 109                 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
 110                                 true_state, false_state);
 111         } END_FOR_EACH_PTR(rel);
 112 }
 113
 114 static void set_extra_expr_true_false(struct expression *expr,
 115                 struct smatch_state *true_state,
 116                 struct smatch_state *false_state)
 117 {
 118         char *name;
 119         struct symbol *sym;
 120
 121         expr = strip_expr(expr);
 122         name = get_variable_from_expr(expr, &sym);
 123         if (!name || !sym)
 124                 goto free;
 125         set_extra_true_false(name, sym, true_state, false_state);
 126 free:
 127         free_string(name);
 128 }
 129
 130 struct smatch_state *filter_range_list(struct smatch_state *orig,
 131                                  struct range_list_sval *rl)
 132 {
 133         struct range_list_sval *res;
 134         struct data_range_sval *tmp;
 135
 136         if (!orig)
 137                 orig = extra_undefined();
 138         res = estate_ranges_sval(orig);
 139
 140         FOR_EACH_PTR(rl, tmp) {
 141                 res = remove_range_sval(res, tmp->min, tmp->max);
 142         } END_FOR_EACH_PTR(tmp);
 143
 144         return alloc_estate_range_list_sval(res);
 145 }
 146
 147 struct smatch_state *filter_range(struct smatch_state *orig,
 148                                  sval_t filter_min, sval_t filter_max)
 149 {
 150         struct range_list_sval *rl;
 151
 152         if (!orig)
 153                 orig = extra_undefined();
 154
 155         rl = remove_range_sval(estate_ranges_sval(orig), filter_min, filter_max);
 156         return alloc_estate_range_list_sval(rl);
 157 }
 158
 159 struct smatch_state *add_filter(struct smatch_state *orig, sval_t sval)
 160 {
 161         return filter_range(orig, sval, sval);
 162 }
 163
 164 static struct smatch_state *merge_func(struct smatch_state *s1, struct smatch_state *s2)
 165 {
 166         struct smatch_state *tmp;
 167         struct range_list_sval *value_ranges;
 168         struct related_list *rlist;
 169
 170         if (estates_equiv(s1, s2))
 171                 return s1;
 172
 173         value_ranges = range_list_union_sval(estate_ranges_sval(s1), estate_ranges_sval(s2));
 174         tmp = alloc_estate_range_list_sval(value_ranges);
 175         rlist = get_shared_relations(estate_related(s1), estate_related(s2));
 176         set_related(&tmp, rlist);
 177
 178         return tmp;
 179 }
 180
 181 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 182 {
 183         struct expression *iter_var;
 184         struct expression *condition;
 185         struct sm_state *sm;
 186         sval_t start;
 187
 188         condition = strip_expr(loop->iterator_pre_condition);
 189         if (!condition)
 190                 return NULL;
 191         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 192                 return NULL;
 193         if (condition->op != SPECIAL_DECREMENT)
 194                 return NULL;
 195
 196         iter_var = condition->unop;
 197         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 198         if (!sm)
 199                 return NULL;
 200         if (sval_cmp_val(estate_min_sval(sm->state), 0) < 0)
 201                 return NULL;
 202         start = estate_max_sval(sm->state);
 203         if  (sval_cmp_val(start, 0) <= 0)
 204                 return NULL;
 205         if (!sval_is_max(start))
 206                 start.value--;
 207
 208         if (condition->type == EXPR_PREOP)
 209                 set_extra_expr_mod(iter_var, alloc_estate_range_sval(ll_to_sval(1), start));
 210         if (condition->type == EXPR_POSTOP)
 211                 set_extra_expr_mod(iter_var, alloc_estate_range_sval(ll_to_sval(0), start));
 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         sval_t start, end;
 221
 222         iter_var = iter_expr->unop;
 223         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 224         if (!sm)
 225                 return NULL;
 226         if (!estate_get_single_value_sval(sm->state, &start))
 227                 return NULL;
 228         if (!get_implied_value_sval(condition->right, &end))
 229                 end = ll_to_sval(whole_range.max);
 230
 231         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 232                 return NULL;
 233
 234         switch (condition->op) {
 235         case SPECIAL_NOTEQUAL:
 236         case '<':
 237                 if (!sval_is_max(end))
 238                         end.value--;
 239                 break;
 240         case SPECIAL_LTE:
 241                 break;
 242         default:
 243                 return NULL;
 244         }
 245         if (sval_cmp(end, start) < 0)
 246                 return NULL;
 247         set_extra_expr_mod(iter_var, alloc_estate_range_sval(start, end));
 248         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 249 }
 250
 251 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 252                                                 struct expression *condition)
 253 {
 254         struct expression *iter_var;
 255         struct sm_state *sm;
 256         sval_t start, end;
 257
 258         iter_var = iter_expr->unop;
 259         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 260         if (!sm)
 261                 return NULL;
 262         if (!estate_get_single_value_sval(sm->state, &start))
 263                 return NULL;
 264         if (!get_implied_value_sval(condition->right, &end))
 265                 end = sval_type_min(get_type(iter_var));
 266         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 267                 return NULL;
 268
 269         switch (condition->op) {
 270         case SPECIAL_NOTEQUAL:
 271         case '>':
 272                 if (!sval_is_min(end) && !sval_is_max(end))
 273                         end.value++;
 274                 break;
 275         case SPECIAL_GTE:
 276                 break;
 277         default:
 278                 return NULL;
 279         }
 280         if (sval_cmp(end, start) > 0)
 281                 return NULL;
 282         set_extra_expr_mod(iter_var, alloc_estate_range_sval(end, start));
 283         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 284 }
 285
 286 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 287 {
 288         struct expression *iter_expr;
 289         struct expression *condition;
 290
 291         if (!loop->iterator_post_statement)
 292                 return NULL;
 293         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 294                 return NULL;
 295         iter_expr = loop->iterator_post_statement->expression;
 296         if (!loop->iterator_pre_condition)
 297                 return NULL;
 298         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 299                 return NULL;
 300         condition = loop->iterator_pre_condition;
 301
 302         if (iter_expr->op == SPECIAL_INCREMENT)
 303                 return handle_canonical_for_inc(iter_expr, condition);
 304         if (iter_expr->op == SPECIAL_DECREMENT)
 305                 return handle_canonical_for_dec(iter_expr, condition);
 306         return NULL;
 307 }
 308
 309 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 310 {
 311         struct sm_state *ret;
 312
 313         __push_fake_cur_slist();
 314         if (!loop->iterator_post_statement)
 315                 ret = handle_canonical_while_count_down(loop);
 316         else
 317                 ret = handle_canonical_for_loops(loop);
 318         *slist = __pop_fake_cur_slist();
 319         return ret;
 320 }
 321
 322 int __iterator_unchanged(struct sm_state *sm)
 323 {
 324         if (!sm)
 325                 return 0;
 326         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 327                 return 1;
 328         return 0;
 329 }
 330
 331 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 332 {
 333         sval_t after_value;
 334
 335         /* paranoid checking.  prolly not needed */
 336         condition = strip_expr(condition);
 337         if (!condition)
 338                 return;
 339         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 340                 return;
 341         if (condition->op != SPECIAL_DECREMENT)
 342                 return;
 343         after_value = estate_min_sval(sm->state);
 344         after_value.value--;
 345         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
 346 }
 347
 348 void __extra_pre_loop_hook_after(struct sm_state *sm,
 349                                 struct statement *iterator,
 350                                 struct expression *condition)
 351 {
 352         struct expression *iter_expr;
 353         char *name;
 354         struct symbol *sym;
 355         sval_t value;
 356         int left = 0;
 357         struct smatch_state *state;
 358         sval_t min, max;
 359
 360         if (!iterator) {
 361                 while_count_down_after(sm, condition);
 362                 return;
 363         }
 364
 365         iter_expr = iterator->expression;
 366
 367         if (condition->type != EXPR_COMPARE)
 368                 return;
 369         if (!get_value_sval(condition->left, &value)) {
 370                 if (!get_value_sval(condition->right, &value))
 371                         return;
 372                 left = 1;
 373         }
 374         if (left)
 375                 name = get_variable_from_expr(condition->left, &sym);
 376         else
 377                 name = get_variable_from_expr(condition->right, &sym);
 378         if (!name || !sym)
 379                 goto free;
 380         if (sym != sm->sym || strcmp(name, sm->name))
 381                 goto free;
 382         state = get_state(my_id, name, sym);
 383         min = estate_min_sval(state);
 384         max = estate_max_sval(state);
 385         if (iter_expr->op == SPECIAL_INCREMENT &&
 386             !sval_is_min(min) && sval_is_max(max))
 387                 set_extra_mod(name, sym, alloc_estate_sval(min));
 388         else if (sval_is_min(min) && !sval_is_max(max))
 389                 set_extra_mod(name, sym, alloc_estate_sval(max));
 390
 391 free:
 392         free_string(name);
 393         return;
 394 }
 395
 396 static struct smatch_state *unmatched_state(struct sm_state *sm)
 397 {
 398         return extra_undefined();
 399 }
 400
 401 static void match_function_call(struct expression *expr)
 402 {
 403         struct expression *arg;
 404         struct expression *tmp;
 405
 406         FOR_EACH_PTR(expr->args, arg) {
 407                 tmp = strip_expr(arg);
 408                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 409                         remove_from_equiv_expr(tmp->unop);
 410                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined());
 411                 }
 412         } END_FOR_EACH_PTR(arg);
 413 }
 414
 415 static void match_assign(struct expression *expr)
 416 {
 417         struct expression *left;
 418         struct expression *right;
 419         struct symbol *right_sym;
 420         char *right_name;
 421         struct symbol *sym;
 422         char *name;
 423         sval_t value;
 424         int known;
 425         sval_t min = ll_to_sval(whole_range.min);
 426         sval_t max = ll_to_sval(whole_range.max);
 427         sval_t tmp;
 428
 429         if (__is_condition_assign(expr))
 430                 return;
 431         left = strip_expr(expr->left);
 432         name = get_variable_from_expr(left, &sym);
 433         if (!name)
 434                 return;
 435         right = strip_parens(expr->right);
 436         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 437                 right = strip_parens(right->left);
 438
 439         if (expr->op == '=' && right->type == EXPR_CALL)
 440                 return;  /* these are handled in match_call_assign() */
 441
 442         right_name = get_variable_from_expr(right, &right_sym);
 443         if (expr->op == '=' && right_name && right_sym) {
 444                 set_equiv(left, right);
 445                 goto free;
 446         }
 447
 448         known = get_implied_value_sval(right, &value);
 449         switch (expr->op) {
 450         case '=': {
 451                 struct range_list_sval *rl = NULL;
 452
 453                 if (get_implied_range_list_sval(right, &rl)) {
 454                         set_extra_mod(name, sym, alloc_estate_range_list_sval(rl));
 455                         goto free;
 456                 }
 457
 458                 if (expr_unsigned(right))
 459                         min = ll_to_sval(0);  // FIXME
 460                 break;
 461         }
 462         case SPECIAL_ADD_ASSIGN:
 463                 if (get_implied_min_sval(left, &tmp)) {
 464                         if (known)
 465                                 min = sval_binop(tmp, '+', value);
 466                         else
 467                                 min = tmp;
 468                 }
 469                 if (!inside_loop() && known && get_implied_max_sval(left, &tmp))
 470                         max = sval_binop(tmp, '+', value);
 471                 break;
 472         case SPECIAL_SUB_ASSIGN:
 473                 if (get_implied_max_sval(left, &tmp)) {
 474                         if (known)
 475                                 max = sval_binop(tmp, '-', value);
 476                         else
 477                                 max = tmp;
 478                 }
 479                 if (!inside_loop() && known && get_implied_min_sval(left, &tmp))
 480                         min = sval_binop(tmp, '-', value);
 481                 break;
 482         }
 483         set_extra_mod(name, sym, alloc_estate_range_sval(min, max));
 484 free:
 485         free_string(right_name);
 486         free_string(name);
 487 }
 488
 489 static void reset_struct_members(struct sm_state *sm)
 490 {
 491         set_extra_mod(sm->name, sm->sym, extra_undefined());
 492 }
 493
 494 static struct smatch_state *increment_state(struct smatch_state *state)
 495 {
 496         sval_t min = estate_min_sval(state);
 497         sval_t max = estate_max_sval(state);
 498
 499         if (inside_loop())
 500                 max = ll_to_sval(whole_range.max);
 501
 502         if (!sval_is_min(min))
 503                 min.value++;
 504         if (!sval_is_max(max))
 505                 max.value++;
 506         return alloc_estate_range_sval(min, max);
 507 }
 508
 509 static struct smatch_state *decrement_state(struct smatch_state *state)
 510 {
 511         sval_t min = estate_min_sval(state);
 512         sval_t max = estate_max_sval(state);
 513
 514         if (inside_loop())
 515                 min = ll_to_sval(whole_range.min);
 516
 517         if (!sval_is_min(min))
 518                 min.value--;
 519         if (!sval_is_max(max))
 520                 max.value--;
 521         return alloc_estate_range_sval(min, max);
 522 }
 523
 524 static void unop_expr(struct expression *expr)
 525 {
 526         struct smatch_state *state;
 527
 528         if (expr->smatch_flags & Handled)
 529                 return;
 530
 531         switch (expr->op) {
 532         case SPECIAL_INCREMENT:
 533                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 534                 state = increment_state(state);
 535                 set_extra_expr_mod(expr->unop, state);
 536                 break;
 537         case SPECIAL_DECREMENT:
 538                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 539                 state = decrement_state(state);
 540                 set_extra_expr_mod(expr->unop, state);
 541                 break;
 542         default:
 543                 return;
 544         }
 545 }
 546
 547 static void asm_expr(struct statement *stmt)
 548 {
 549
 550         struct expression *expr;
 551         int state = 0;
 552
 553         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 554                 switch (state) {
 555                 case 0: /* identifier */
 556                 case 1: /* constraint */
 557                         state++;
 558                         continue;
 559                 case 2: /* expression */
 560                         state = 0;
 561                         set_extra_expr_mod(expr, extra_undefined());
 562                         continue;
 563                 }
 564         } END_FOR_EACH_PTR(expr);
 565 }
 566
 567 static void delete_state_tracker(struct tracker *t)
 568 {
 569         remove_from_equiv(t->name, t->sym);
 570         delete_state(t->owner, t->name, t->sym);
 571 }
 572
 573 static void scoped_state_extra(const char *name, struct symbol *sym)
 574 {
 575         struct tracker *t;
 576
 577         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 578         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 579 }
 580
 581 static void match_declarations(struct symbol *sym)
 582 {
 583         const char *name;
 584
 585         if (sym->ident) {
 586                 name = sym->ident->name;
 587                 if (!sym->initializer) {
 588                         set_state(SMATCH_EXTRA, name, sym, extra_undefined());
 589                         scoped_state_extra(name, sym);
 590                 }
 591         }
 592 }
 593
 594 static void check_dereference(struct expression *expr)
 595 {
 596         set_extra_expr_nomod(expr, alloc_estate_range_sval(valid_ptr_min_sval, valid_ptr_max_sval));
 597 }
 598
 599 static void match_dereferences(struct expression *expr)
 600 {
 601         if (expr->type != EXPR_PREOP)
 602                 return;
 603         check_dereference(expr->unop);
 604 }
 605
 606 static void match_pointer_as_array(struct expression *expr)
 607 {
 608         if (!is_array(expr))
 609                 return;
 610         check_dereference(expr->unop->left);
 611 }
 612
 613 static void set_param_dereferenced(struct expression *arg, char *unused)
 614 {
 615         check_dereference(arg);
 616 }
 617
 618 static void match_function_def(struct symbol *sym)
 619 {
 620         struct symbol *arg;
 621
 622         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 623                 if (!arg->ident)
 624                         continue;
 625                 set_state(my_id, arg->ident->name, arg, extra_undefined());
 626         } END_FOR_EACH_PTR(arg);
 627 }
 628
 629 static int match_func_comparison(struct expression *expr)
 630 {
 631         struct expression *left = strip_expr(expr->left);
 632         struct expression *right = strip_expr(expr->right);
 633         sval_t sval;
 634
 635         if (left->type == EXPR_CALL) {
 636                 if (!get_implied_value_sval(right, &sval))
 637                         return 1;
 638                 function_comparison(expr->op, left, sval, 1);
 639                 return 1;
 640         }
 641
 642         if (right->type == EXPR_CALL) {
 643                 if (!get_implied_value_sval(left, &sval))
 644                         return 1;
 645                 function_comparison(expr->op, right, sval, 0);
 646                 return 1;
 647         }
 648
 649         return 0;
 650 }
 651
 652 static sval_t add_one(sval_t sval)
 653 {
 654         sval.value++;
 655         return sval;
 656 }
 657
 658 static sval_t sub_one(sval_t sval)
 659 {
 660         sval.value--;
 661         return sval;
 662 }
 663
 664 static void match_comparison(struct expression *expr)
 665 {
 666         struct expression *left = strip_expr(expr->left);
 667         struct expression *right = strip_expr(expr->right);
 668         struct range_list_sval *left_orig;
 669         struct range_list_sval *left_true;
 670         struct range_list_sval *left_false;
 671         struct range_list_sval *right_orig;
 672         struct range_list_sval *right_true;
 673         struct range_list_sval *right_false;
 674         struct smatch_state *left_true_state;
 675         struct smatch_state *left_false_state;
 676         struct smatch_state *right_true_state;
 677         struct smatch_state *right_false_state;
 678         sval_t min, max;
 679         int left_postop = 0;
 680         int right_postop = 0;
 681
 682         if (match_func_comparison(expr))
 683                 return;
 684
 685         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 686                 if (left->type == EXPR_POSTOP) {
 687                         left->smatch_flags |= Handled;
 688                         left_postop = left->op;
 689                 }
 690                 left = strip_expr(left->unop);
 691         }
 692
 693         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 694                 if (right->type == EXPR_POSTOP) {
 695                         right->smatch_flags |= Handled;
 696                         right_postop = right->op;
 697                 }
 698                 right = strip_expr(right->unop);
 699         }
 700
 701         min = sval_type_min(&llong_ctype);
 702         max = sval_type_max(&llong_ctype);
 703         if (get_implied_range_list_sval(left, &left_orig))
 704                 left_orig = cast_rl(left_orig, &llong_ctype); // temporary hack to make things llong_ctype
 705         else
 706                 left_orig = alloc_range_list_sval(min, max);
 707
 708         if (get_implied_range_list_sval(right, &right_orig))
 709                 right_orig = cast_rl(right_orig, &llong_ctype); // temporary hack to make things llong_ctype
 710         else
 711                 right_orig = alloc_range_list_sval(min, max);
 712
 713         left_true = clone_range_list_sval(left_orig);
 714         left_false = clone_range_list_sval(left_orig);
 715         right_true = clone_range_list_sval(right_orig);
 716         right_false = clone_range_list_sval(right_orig);
 717
 718         switch (expr->op) {
 719         case '<':
 720         case SPECIAL_UNSIGNED_LT:
 721                 if (!sval_is_max(rl_max_sval(right_orig))) {
 722                         left_true = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 723                 }
 724                 if (!sval_is_min(rl_min_sval(right_orig))) {
 725                         left_false = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 726                 }
 727
 728                 if (!sval_is_min(rl_min_sval(left_orig)))
 729                         right_true = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 730                 if (!sval_is_max(rl_max_sval(left_orig)))
 731                         right_false = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 732                 break;
 733         case SPECIAL_UNSIGNED_LTE:
 734         case SPECIAL_LTE:
 735                 if (!sval_is_max(rl_max_sval(right_orig)))
 736                         left_true = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 737                 if (!sval_is_min(rl_min_sval(right_orig)))
 738                         left_false = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 739
 740                 if (!sval_is_min(rl_min_sval(left_orig)))
 741                         right_true = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 742                 if (!sval_is_max(rl_max_sval(left_orig)))
 743                         right_false = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 744                 break;
 745         case SPECIAL_EQUAL:
 746                 if (!sval_is_max(rl_max_sval(right_orig))) {
 747                         left_true = remove_range_sval(left_true, add_one(rl_max_sval(right_orig)), max);
 748                 }
 749                 if (!sval_is_min(rl_min_sval(right_orig))) {
 750                         left_true = remove_range_sval(left_true, min, sub_one(rl_min_sval(right_orig)));
 751                 }
 752                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 753                         left_false = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 754
 755                 if (!sval_is_max(rl_max_sval(left_orig)))
 756                         right_true = remove_range_sval(right_true, add_one(rl_max_sval(left_orig)), max);
 757                 if (!sval_is_min(rl_min_sval(left_orig)))
 758                         right_true = remove_range_sval(right_true, min, sub_one(rl_min_sval(left_orig)));
 759                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 760                         right_false = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 761                 break;
 762         case SPECIAL_UNSIGNED_GTE:
 763         case SPECIAL_GTE:
 764                 if (!sval_is_min(rl_min_sval(right_orig)))
 765                         left_true = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 766                 if (!sval_is_max(rl_max_sval(right_orig)))
 767                         left_false = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 768
 769                 if (!sval_is_max(rl_max_sval(left_orig)))
 770                         right_true = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 771                 if (!sval_is_min(rl_min_sval(left_orig)))
 772                         right_false = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 773                 break;
 774         case '>':
 775         case SPECIAL_UNSIGNED_GT:
 776                 if (!sval_is_min(rl_min_sval(right_orig)))
 777                         left_true = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 778                 if (!sval_is_max(rl_max_sval(right_orig)))
 779                         left_false = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 780
 781                 if (!sval_is_max(rl_max_sval(left_orig)))
 782                         right_true = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 783                 if (!sval_is_min(rl_min_sval(left_orig)))
 784                         right_false = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 785                 break;
 786         case SPECIAL_NOTEQUAL:
 787                 if (!sval_is_max(rl_max_sval(right_orig)))
 788                         left_false = remove_range_sval(left_false, add_one(rl_max_sval(right_orig)), max);
 789                 if (!sval_is_min(rl_min_sval(right_orig)))
 790                         left_false = remove_range_sval(left_false, min, sub_one(rl_min_sval(right_orig)));
 791                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 792                         left_true = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 793
 794                 if (!sval_is_max(rl_max_sval(left_orig)))
 795                         right_false = remove_range_sval(right_false, add_one(rl_max_sval(left_orig)), max);
 796                 if (!sval_is_min(rl_min_sval(left_orig)))
 797                         right_false = remove_range_sval(right_false, min, sub_one(rl_min_sval(left_orig)));
 798                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 799                         right_true = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 800                 break;
 801         default:
 802                 return;
 803         }
 804
 805         left_true_state = alloc_estate_range_list_sval(left_true);
 806         left_false_state = alloc_estate_range_list_sval(left_false);
 807         right_true_state = alloc_estate_range_list_sval(right_true);
 808         right_false_state = alloc_estate_range_list_sval(right_false);
 809
 810         if (left_postop == SPECIAL_INCREMENT) {
 811                 left_true_state = increment_state(left_true_state);
 812                 left_false_state = increment_state(left_false_state);
 813         }
 814         if (left_postop == SPECIAL_DECREMENT) {
 815                 left_true_state = decrement_state(left_true_state);
 816                 left_false_state = decrement_state(left_false_state);
 817         }
 818         if (right_postop == SPECIAL_INCREMENT) {
 819                 right_true_state = increment_state(right_true_state);
 820                 right_false_state = increment_state(right_false_state);
 821         }
 822         if (right_postop == SPECIAL_DECREMENT) {
 823                 right_true_state = decrement_state(right_true_state);
 824                 right_false_state = decrement_state(right_false_state);
 825         }
 826
 827         set_extra_expr_true_false(left, left_true_state, left_false_state);
 828         set_extra_expr_true_false(right, right_true_state, right_false_state);
 829 }
 830
 831 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 832 void __extra_match_condition(struct expression *expr)
 833 {
 834         struct symbol *sym;
 835         char *name;
 836         struct smatch_state *pre_state;
 837         struct smatch_state *true_state;
 838         struct smatch_state *false_state;
 839
 840         expr = strip_expr(expr);
 841         switch (expr->type) {
 842         case EXPR_CALL:
 843                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 844                 return;
 845         case EXPR_PREOP:
 846         case EXPR_SYMBOL:
 847         case EXPR_DEREF:
 848                 name = get_variable_from_expr(expr, &sym);
 849                 if (!name)
 850                         return;
 851                 pre_state = get_state(my_id, name, sym);
 852                 true_state = add_filter(pre_state, ll_to_sval(0));
 853                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 854                         false_state = alloc_estate_sval(ll_to_sval(0));
 855                 else
 856                         false_state = alloc_estate_empty();
 857                 set_extra_true_false(name, sym, true_state, false_state);
 858                 free_string(name);
 859                 return;
 860         case EXPR_COMPARE:
 861                 match_comparison(expr);
 862                 return;
 863         case EXPR_ASSIGNMENT:
 864                 __extra_match_condition(expr->left);
 865                 return;
 866         }
 867 }
 868
 869 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 870 int implied_not_equal(struct expression *expr, long long val)
 871 {
 872         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 873 }
 874
 875 int get_implied_range_list_sval(struct expression *expr, struct range_list_sval **rl)
 876 {
 877         sval_t sval;
 878         struct smatch_state *state;
 879         sval_t min, max;
 880
 881         *rl = NULL;
 882
 883         expr = strip_parens(expr);
 884         if (!expr)
 885                 return 0;
 886
 887         state = get_state_expr(my_id, expr);
 888         if (state) {
 889                 *rl = clone_range_list_sval(estate_ranges_sval(state));
 890                 goto out;
 891         }
 892
 893         if (expr->type == EXPR_CALL) {
 894                 if (get_implied_return_sval(expr, rl))
 895                         goto out;
 896                 *rl = db_return_vals(expr);
 897                 goto out;
 898         }
 899
 900         if (get_implied_value_sval(expr, &sval)) {
 901                 add_range_sval(rl, sval, sval);
 902                 goto out;
 903         }
 904
 905         if (expr->type == EXPR_BINOP && expr->op == '%') {
 906                 if (!get_implied_value_sval(expr->right, &sval))
 907                         return 0;
 908                 add_range_sval(rl, ll_to_sval(0), ll_to_sval(sval.value - 1));
 909                 goto out;
 910         }
 911
 912         if (!get_implied_min_sval(expr, &min))
 913                 return 0;
 914         if (!get_implied_max_sval(expr, &max))
 915                 return 0;
 916
 917         *rl = alloc_range_list_sval(min, max);
 918
 919 out:
 920         if (is_whole_range_rl_sval(*rl))
 921                 return 0;
 922         return 1;
 923 }
 924
 925 int is_whole_range(struct smatch_state *state)
 926 {
 927         return is_whole_range_rl_sval(estate_ranges_sval(state));
 928 }
 929
 930 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 931 {
 932         if (is_whole_range(state))
 933                 return;
 934         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 935 }
 936
 937 static void match_call_info(struct expression *expr)
 938 {
 939         struct range_list_sval *rl = NULL;
 940         struct expression *arg;
 941         char *name;
 942         int i = 0;
 943
 944         name = get_fnptr_name(expr->fn);
 945         if (!name)
 946                 return;
 947
 948         FOR_EACH_PTR(expr->args, arg) {
 949                 if (get_implied_range_list_sval(arg, &rl) && !is_whole_range_rl_sval(rl)) {
 950                         sm_msg("info: passes param_value '%s' %d '$$' %s %s",
 951                                name, i, show_ranges_sval(rl),
 952                                is_static(expr->fn) ? "static" : "global");
 953                 }
 954                 i++;
 955         } END_FOR_EACH_PTR(arg);
 956
 957         free_string(name);
 958 }
 959
 960 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
 961 {
 962         struct range_list_sval *rl = NULL;
 963         struct smatch_state *state;
 964         char fullname[256];
 965
 966         if (strncmp(key, "$$", 2))
 967                 return;
 968
 969         snprintf(fullname, 256, "%s%s", name, key + 2);
 970         get_value_ranges_sval(value, &rl);
 971         state = alloc_estate_range_list_sval(rl);
 972         set_state(SMATCH_EXTRA, fullname, sym, state);
 973 }
 974
 975 static void match_call_assign(struct expression *expr)
 976 {
 977         if (expr->op != '=')
 978                 return;
 979
 980         /* if we have a db set up this gets set in smatch_function_hooks.c */
 981         if (option_no_db)
 982                 set_extra_expr_mod(expr->left, extra_undefined());
 983 }
 984
 985 void register_smatch_extra(int id)
 986 {
 987         my_id = id;
 988
 989         alloc_estate_undefined();
 990         add_merge_hook(my_id, &merge_func);
 991         add_unmatched_state_hook(my_id, &unmatched_state);
 992         add_hook(&unop_expr, OP_HOOK);
 993         add_hook(&asm_expr, ASM_HOOK);
 994         add_hook(&match_function_def, FUNC_DEF_HOOK);
 995         add_hook(&match_declarations, DECLARATION_HOOK);
 996         if (option_info) {
 997                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 998                 add_member_info_callback(my_id, struct_member_callback);
 999         }
1000         add_definition_db_callback(set_param_value, PARAM_VALUE);
1001 }
1002
1003 void register_smatch_extra_late(int id)
1004 {
1005         add_hook(&match_dereferences, DEREF_HOOK);
1006         add_hook(&match_pointer_as_array, OP_HOOK);
1007         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1008         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1009         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1010         add_hook(&match_assign, ASSIGNMENT_HOOK);
1011         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
1012 }