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 = last_ptr_list((struct ptr_list *)big_statement_stack);
  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(struct smatch_state *orig,
 131                                  long long filter_min, long long filter_max)
 132 {
 133         struct range_list *rl;
 134
 135         if (!orig)
 136                 orig = extra_undefined();
 137
 138         rl = remove_range(estate_ranges(orig), filter_min, filter_max);
 139         return alloc_estate_range_list(rl);
 140 }
 141
 142 struct smatch_state *add_filter(struct smatch_state *orig, long long num)
 143 {
 144         return filter_range(orig, num, num);
 145 }
 146
 147 static struct smatch_state *merge_func(struct smatch_state *s1, struct smatch_state *s2)
 148 {
 149         struct smatch_state *tmp;
 150         struct range_list *value_ranges;
 151         struct related_list *rlist;
 152
 153         if (estates_equiv(s1, s2))
 154                 return s1;
 155
 156         value_ranges = range_list_union(estate_ranges(s1), estate_ranges(s2));
 157         tmp = alloc_estate_range_list(value_ranges);
 158         rlist = get_shared_relations(estate_related(s1), estate_related(s2));
 159         set_related(&tmp, rlist);
 160
 161         return tmp;
 162 }
 163
 164 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 165 {
 166         struct expression *iter_var;
 167         struct expression *condition;
 168         struct sm_state *sm;
 169         long long start;
 170
 171         condition = strip_expr(loop->iterator_pre_condition);
 172         if (!condition)
 173                 return NULL;
 174         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 175                 return NULL;
 176         if (condition->op != SPECIAL_DECREMENT)
 177                 return NULL;
 178
 179         iter_var = condition->unop;
 180         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 181         if (!sm)
 182                 return NULL;
 183         if (estate_min(sm->state) < 0)
 184                 return NULL;
 185         start = estate_max(sm->state);
 186         if  (start <= 0)
 187                 return NULL;
 188         if (start != whole_range.max)
 189                 start--;
 190
 191         if (condition->type == EXPR_PREOP)
 192                 set_extra_expr_mod(iter_var, alloc_estate_range(1, start));
 193         if (condition->type == EXPR_POSTOP)
 194                 set_extra_expr_mod(iter_var, alloc_estate_range(0, start));
 195         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 196 }
 197
 198 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 199                                                 struct expression *condition)
 200 {
 201         struct expression *iter_var;
 202         struct sm_state *sm;
 203         long long start;
 204         long long end;
 205
 206         iter_var = iter_expr->unop;
 207         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 208         if (!sm)
 209                 return NULL;
 210         if (!estate_get_single_value(sm->state, &start))
 211                 return NULL;
 212         if (!get_implied_value(condition->right, &end))
 213                 end = whole_range.max;
 214         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 215                 return NULL;
 216
 217         switch (condition->op) {
 218         case SPECIAL_NOTEQUAL:
 219         case '<':
 220                 if (end != whole_range.max)
 221                         end--;
 222                 break;
 223         case SPECIAL_LTE:
 224                 break;
 225         default:
 226                 return NULL;
 227         }
 228         if (end < start)
 229                 return NULL;
 230         set_extra_expr_mod(iter_var, alloc_estate_range(start, end));
 231         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 232 }
 233
 234 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 235                                                 struct expression *condition)
 236 {
 237         struct expression *iter_var;
 238         struct sm_state *sm;
 239         long long start;
 240         long long end;
 241
 242         iter_var = iter_expr->unop;
 243         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 244         if (!sm)
 245                 return NULL;
 246         if (!estate_get_single_value(sm->state, &start))
 247                 return NULL;
 248         if (!get_implied_value(condition->right, &end))
 249                 end = whole_range.max;
 250         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 251                 return NULL;
 252
 253         switch (condition->op) {
 254         case SPECIAL_NOTEQUAL:
 255         case '>':
 256                 if (end != whole_range.min)
 257                         end++;
 258                 break;
 259         case SPECIAL_GTE:
 260                 break;
 261         default:
 262                 return NULL;
 263         }
 264         if (end > start)
 265                 return NULL;
 266         set_extra_expr_mod(iter_var, alloc_estate_range(end, start));
 267         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 268 }
 269
 270 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 271 {
 272         struct expression *iter_expr;
 273         struct expression *condition;
 274
 275         if (!loop->iterator_post_statement)
 276                 return NULL;
 277         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 278                 return NULL;
 279         iter_expr = loop->iterator_post_statement->expression;
 280         if (!loop->iterator_pre_condition)
 281                 return NULL;
 282         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 283                 return NULL;
 284         condition = loop->iterator_pre_condition;
 285
 286         if (iter_expr->op == SPECIAL_INCREMENT)
 287                 return handle_canonical_for_inc(iter_expr, condition);
 288         if (iter_expr->op == SPECIAL_DECREMENT)
 289                 return handle_canonical_for_dec(iter_expr, condition);
 290         return NULL;
 291 }
 292
 293 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 294 {
 295         struct sm_state *ret;
 296
 297         __push_fake_cur_slist();
 298         if (!loop->iterator_post_statement)
 299                 ret = handle_canonical_while_count_down(loop);
 300         else
 301                 ret = handle_canonical_for_loops(loop);
 302         *slist = __pop_fake_cur_slist();
 303         return ret;
 304 }
 305
 306 int __iterator_unchanged(struct sm_state *sm)
 307 {
 308         if (!sm)
 309                 return 0;
 310         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 311                 return 1;
 312         return 0;
 313 }
 314
 315 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 316 {
 317         long long after_value;
 318
 319         /* paranoid checking.  prolly not needed */
 320         condition = strip_expr(condition);
 321         if (!condition)
 322                 return;
 323         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 324                 return;
 325         if (condition->op != SPECIAL_DECREMENT)
 326                 return;
 327         after_value = estate_min(sm->state);
 328         after_value--;
 329         set_extra_mod(sm->name, sm->sym, alloc_estate(after_value));
 330 }
 331
 332 void __extra_pre_loop_hook_after(struct sm_state *sm,
 333                                 struct statement *iterator,
 334                                 struct expression *condition)
 335 {
 336         struct expression *iter_expr;
 337         char *name;
 338         struct symbol *sym;
 339         long long value;
 340         int left = 0;
 341         struct smatch_state *state;
 342         long long min, max;
 343
 344         if (!iterator) {
 345                 while_count_down_after(sm, condition);
 346                 return;
 347         }
 348
 349         iter_expr = iterator->expression;
 350
 351         if (condition->type != EXPR_COMPARE)
 352                 return;
 353         if (!get_value(condition->left, &value)) {
 354                 if (!get_value(condition->right, &value))
 355                         return;
 356                 left = 1;
 357         }
 358         if (left)
 359                 name = get_variable_from_expr(condition->left, &sym);
 360         else
 361                 name = get_variable_from_expr(condition->right, &sym);
 362         if (!name || !sym)
 363                 goto free;
 364         if (sym != sm->sym || strcmp(name, sm->name))
 365                 goto free;
 366         state = get_state(my_id, name, sym);
 367         min = estate_min(state);
 368         max = estate_max(state);
 369         if (iter_expr->op == SPECIAL_INCREMENT &&
 370                 min != whole_range.min &&
 371                 max == whole_range.max) {
 372                 set_extra_mod(name, sym, alloc_estate(min));
 373         } else if (min == whole_range.min && max != whole_range.max) {
 374                 set_extra_mod(name, sym, alloc_estate(max));
 375         }
 376 free:
 377         free_string(name);
 378         return;
 379 }
 380
 381 static struct smatch_state *unmatched_state(struct sm_state *sm)
 382 {
 383         return extra_undefined();
 384 }
 385
 386 static void match_function_call(struct expression *expr)
 387 {
 388         struct expression *arg;
 389         struct expression *tmp;
 390
 391         FOR_EACH_PTR(expr->args, arg) {
 392                 tmp = strip_expr(arg);
 393                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 394                         remove_from_equiv_expr(tmp->unop);
 395                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined());
 396                 }
 397         } END_FOR_EACH_PTR(arg);
 398 }
 399
 400 static void match_assign(struct expression *expr)
 401 {
 402         struct expression *left;
 403         struct expression *right;
 404         struct symbol *right_sym;
 405         char *right_name;
 406         struct symbol *sym;
 407         char *name;
 408         long long value;
 409         int known;
 410         long long min = whole_range.min;
 411         long long max = whole_range.max;
 412         long long tmp;
 413
 414         if (__is_condition_assign(expr))
 415                 return;
 416         left = strip_expr(expr->left);
 417         name = get_variable_from_expr(left, &sym);
 418         if (!name)
 419                 return;
 420         right = strip_parens(expr->right);
 421         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 422                 right = strip_parens(right->left);
 423
 424         if (expr->op == '=' && right->type == EXPR_CALL)
 425                 return;  /* these are handled in match_call_assign() */
 426
 427         right_name = get_variable_from_expr(right, &right_sym);
 428         if (expr->op == '=' && right_name && right_sym) {
 429                 set_equiv(left, right);
 430                 goto free;
 431         }
 432
 433         known = get_implied_value(right, &value);
 434         switch (expr->op) {
 435         case '=': {
 436                 struct range_list *rl = NULL;
 437
 438                 if (get_implied_range_list(right, &rl)) {
 439                         set_extra_mod(name, sym, alloc_estate_range_list(rl));
 440                         goto free;
 441                 }
 442
 443                 if (expr_unsigned(right))
 444                         min = 0;
 445                 break;
 446         }
 447         case SPECIAL_ADD_ASSIGN:
 448                 if (get_implied_min(left, &tmp)) {
 449                         if (known)
 450                                 min = tmp + value;
 451                         else
 452                                 min = tmp;
 453                 }
 454                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 455                                 max = tmp + value;
 456                 break;
 457         case SPECIAL_SUB_ASSIGN:
 458                 if (get_implied_max(left, &tmp)) {
 459                         if (known)
 460                                 max = tmp - value;
 461                         else
 462                                 max = tmp;
 463                 }
 464                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 465                                 min = tmp - value;
 466                 break;
 467         }
 468         set_extra_mod(name, sym, alloc_estate_range(min, max));
 469 free:
 470         free_string(right_name);
 471         free_string(name);
 472 }
 473
 474 static void reset_struct_members(struct sm_state *sm)
 475 {
 476         set_extra_mod(sm->name, sm->sym, extra_undefined());
 477 }
 478
 479 static struct smatch_state *increment_state(struct smatch_state *state)
 480 {
 481         long long min = estate_min(state);
 482         long long max = estate_max(state);
 483
 484         if (inside_loop())
 485                 max = whole_range.max;
 486
 487         if (min != whole_range.min)
 488                 min++;
 489         if (max != whole_range.max)
 490                 max++;
 491         return alloc_estate_range(min, max);
 492 }
 493
 494 static struct smatch_state *decrement_state(struct smatch_state *state)
 495 {
 496         long long min = estate_min(state);
 497         long long max = estate_max(state);
 498
 499         if (inside_loop())
 500                 min = whole_range.min;
 501
 502         if (min != whole_range.min)
 503                 min--;
 504         if (max != whole_range.max)
 505                 max--;
 506         return alloc_estate_range(min, max);
 507 }
 508
 509 static void unop_expr(struct expression *expr)
 510 {
 511         struct smatch_state *state;
 512
 513         if (expr->smatch_flags & Handled)
 514                 return;
 515
 516         switch (expr->op) {
 517         case SPECIAL_INCREMENT:
 518                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 519                 state = increment_state(state);
 520                 set_extra_expr_mod(expr->unop, state);
 521                 break;
 522         case SPECIAL_DECREMENT:
 523                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 524                 state = decrement_state(state);
 525                 set_extra_expr_mod(expr->unop, state);
 526                 break;
 527         default:
 528                 return;
 529         }
 530 }
 531
 532 static void delete_state_tracker(struct tracker *t)
 533 {
 534         remove_from_equiv(t->name, t->sym);
 535         delete_state(t->owner, t->name, t->sym);
 536 }
 537
 538 static void scoped_state_extra(const char *name, struct symbol *sym)
 539 {
 540         struct tracker *t;
 541
 542         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 543         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 544 }
 545
 546 static void match_declarations(struct symbol *sym)
 547 {
 548         const char *name;
 549
 550         if (sym->ident) {
 551                 name = sym->ident->name;
 552                 if (!sym->initializer) {
 553                         set_state(SMATCH_EXTRA, name, sym, extra_undefined());
 554                         scoped_state_extra(name, sym);
 555                 }
 556         }
 557 }
 558
 559 static void check_dereference(struct expression *expr)
 560 {
 561         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min, valid_ptr_max));
 562 }
 563
 564 static void match_dereferences(struct expression *expr)
 565 {
 566         if (expr->type != EXPR_PREOP)
 567                 return;
 568         check_dereference(expr->unop);
 569 }
 570
 571 static void match_pointer_as_array(struct expression *expr)
 572 {
 573         if (!is_array(expr))
 574                 return;
 575         check_dereference(expr->unop->left);
 576 }
 577
 578 static void set_param_dereferenced(struct expression *arg, char *unused)
 579 {
 580         check_dereference(arg);
 581 }
 582
 583 static void match_function_def(struct symbol *sym)
 584 {
 585         struct symbol *arg;
 586
 587         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 588                 if (!arg->ident)
 589                         continue;
 590                 set_state(my_id, arg->ident->name, arg, extra_undefined());
 591         } END_FOR_EACH_PTR(arg);
 592 }
 593
 594 static int match_func_comparison(struct expression *expr)
 595 {
 596         struct expression *left = strip_expr(expr->left);
 597         struct expression *right = strip_expr(expr->right);
 598         long long val;
 599
 600         if (left->type == EXPR_CALL) {
 601                 if (!get_implied_value(right, &val))
 602                         return 1;
 603                 function_comparison(expr->op, left, val, 1);
 604                 return 1;
 605         }
 606
 607         if (right->type == EXPR_CALL) {
 608                 if (!get_implied_value(left, &val))
 609                         return 1;
 610                 function_comparison(expr->op, right, val, 0);
 611                 return 1;
 612         }
 613
 614         return 0;
 615 }
 616
 617 static void match_comparison(struct expression *expr)
 618 {
 619         struct expression *left = strip_expr(expr->left);
 620         struct expression *right = strip_expr(expr->right);
 621         struct range_list *left_orig;
 622         struct range_list *left_true;
 623         struct range_list *left_false;
 624         struct range_list *right_orig;
 625         struct range_list *right_true;
 626         struct range_list *right_false;
 627         struct smatch_state *left_true_state;
 628         struct smatch_state *left_false_state;
 629         struct smatch_state *right_true_state;
 630         struct smatch_state *right_false_state;
 631         int left_postop = 0;
 632         int right_postop = 0;
 633
 634         if (match_func_comparison(expr))
 635                 return;
 636
 637         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 638                 if (left->type == EXPR_POSTOP) {
 639                         left->smatch_flags |= Handled;
 640                         left_postop = left->op;
 641                 }
 642                 left = strip_expr(left->unop);
 643         }
 644
 645         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 646                 if (right->type == EXPR_POSTOP) {
 647                         right->smatch_flags |= Handled;
 648                         right_postop = right->op;
 649                 }
 650                 right = strip_expr(right->unop);
 651         }
 652
 653         if (!get_implied_range_list(left, &left_orig))
 654                 left_orig = alloc_range_list(whole_range.min, whole_range.max);
 655         if (!get_implied_range_list(right, &right_orig))
 656                 right_orig = alloc_range_list(whole_range.min, whole_range.max);
 657
 658         left_true = clone_range_list(left_orig);
 659         left_false = clone_range_list(left_orig);
 660         right_true = clone_range_list(right_orig);
 661         right_false = clone_range_list(right_orig);
 662
 663         switch (expr->op) {
 664         case '<':
 665         case SPECIAL_UNSIGNED_LT:
 666                 if (rl_max(right_orig) != whole_range.max)
 667                         left_true = remove_range(left_orig, rl_max(right_orig), whole_range.max);
 668                 if (rl_min(right_orig) != whole_range.min)
 669                         left_false = remove_range(left_orig, whole_range.min, rl_min(right_orig) - 1);
 670
 671                 if (rl_min(left_orig) != whole_range.min)
 672                         right_true = remove_range(right_orig, whole_range.min, rl_min(left_orig));
 673                 if (rl_max(left_orig) != whole_range.max)
 674                         right_false = remove_range(right_orig, rl_max(left_orig) + 1, whole_range.max);
 675                 break;
 676         case SPECIAL_UNSIGNED_LTE:
 677         case SPECIAL_LTE:
 678                 if (rl_max(right_orig) != whole_range.max)
 679                         left_true = remove_range(left_orig, rl_max(right_orig) + 1, whole_range.max);
 680                 if (rl_min(right_orig) != whole_range.min)
 681                         left_false = remove_range(left_orig, whole_range.min, rl_min(right_orig));
 682
 683                 if (rl_min(left_orig) != whole_range.min)
 684                         right_true = remove_range(right_orig, whole_range.min, rl_min(left_orig) - 1);
 685                 if (rl_max(left_orig) != whole_range.max)
 686                         right_false = remove_range(right_orig, rl_max(left_orig), whole_range.max);
 687                 break;
 688         case SPECIAL_EQUAL:
 689                 if (rl_max(right_orig) != whole_range.max)
 690                         left_true = remove_range(left_true, rl_max(right_orig) + 1, whole_range.max);
 691                 if (rl_min(right_orig) != whole_range.min)
 692                         left_true = remove_range(left_true, whole_range.min, rl_min(right_orig) - 1);
 693                 if (rl_min(right_orig) == rl_max(right_orig))
 694                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 695
 696                 if (rl_max(left_orig) != whole_range.max)
 697                         right_true = remove_range(right_true, rl_max(left_orig) + 1, whole_range.max);
 698                 if (rl_min(left_orig) != whole_range.min)
 699                         right_true = remove_range(right_true, whole_range.min, rl_min(left_orig) - 1);
 700                 if (rl_min(left_orig) == rl_max(left_orig))
 701                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 702                 break;
 703         case SPECIAL_UNSIGNED_GTE:
 704         case SPECIAL_GTE:
 705                 if (rl_min(right_orig) != whole_range.min)
 706                         left_true = remove_range(left_orig, whole_range.min, rl_min(right_orig) - 1);
 707                 if (rl_max(right_orig) != whole_range.max)
 708                         left_false = remove_range(left_orig, rl_max(right_orig), whole_range.max);
 709
 710                 if (rl_max(left_orig) != whole_range.max)
 711                         right_true = remove_range(right_orig, rl_max(left_orig) + 1, whole_range.max);
 712                 if (rl_min(left_orig) != whole_range.min)
 713                         right_false = remove_range(right_orig, whole_range.min, rl_min(left_orig));
 714                 break;
 715         case '>':
 716         case SPECIAL_UNSIGNED_GT:
 717                 if (rl_min(right_orig) != whole_range.min)
 718                         left_true = remove_range(left_orig, whole_range.min, rl_min(right_orig));
 719                 if (rl_max(right_orig) != whole_range.max)
 720                         left_false = remove_range(left_orig, rl_max(right_orig) + 1, whole_range.max);
 721
 722                 if (rl_max(left_orig) != whole_range.max)
 723                         right_true = remove_range(right_orig, rl_max(left_orig), whole_range.max);
 724                 if (rl_min(left_orig) != whole_range.min)
 725                         right_false = remove_range(right_orig, whole_range.min, rl_min(left_orig) - 1);
 726                 break;
 727         case SPECIAL_NOTEQUAL:
 728                 if (rl_max(right_orig) != whole_range.max)
 729                         left_false = remove_range(left_false, rl_max(right_orig) + 1, whole_range.max);
 730                 if (rl_min(right_orig) != whole_range.min)
 731                         left_false = remove_range(left_false, whole_range.min, rl_min(right_orig) - 1);
 732                 if (rl_min(right_orig) == rl_max(right_orig))
 733                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 734
 735                 if (rl_max(left_orig) != whole_range.max)
 736                         right_false = remove_range(right_false, rl_max(left_orig) + 1, whole_range.max);
 737                 if (rl_min(left_orig) != whole_range.min)
 738                         right_false = remove_range(right_false, whole_range.min, rl_min(left_orig) - 1);
 739                 if (rl_min(left_orig) == rl_max(left_orig))
 740                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 741                 break;
 742         default:
 743                 return;
 744         }
 745
 746         left_true_state = alloc_estate_range_list(left_true);
 747         left_false_state = alloc_estate_range_list(left_false);
 748         right_true_state = alloc_estate_range_list(right_true);
 749         right_false_state = alloc_estate_range_list(right_false);
 750
 751         if (left_postop == SPECIAL_INCREMENT) {
 752                 left_true_state = increment_state(left_true_state);
 753                 left_false_state = increment_state(left_false_state);
 754         }
 755         if (left_postop == SPECIAL_DECREMENT) {
 756                 left_true_state = decrement_state(left_true_state);
 757                 left_false_state = decrement_state(left_false_state);
 758         }
 759         if (right_postop == SPECIAL_INCREMENT) {
 760                 right_true_state = increment_state(right_true_state);
 761                 right_false_state = increment_state(right_false_state);
 762         }
 763         if (right_postop == SPECIAL_DECREMENT) {
 764                 right_true_state = decrement_state(right_true_state);
 765                 right_false_state = decrement_state(right_false_state);
 766         }
 767
 768         set_extra_expr_true_false(left, left_true_state, left_false_state);
 769         set_extra_expr_true_false(right, right_true_state, right_false_state);
 770 }
 771
 772 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 773 void __extra_match_condition(struct expression *expr)
 774 {
 775         struct symbol *sym;
 776         char *name;
 777         struct smatch_state *pre_state;
 778         struct smatch_state *true_state;
 779         struct smatch_state *false_state;
 780
 781         expr = strip_expr(expr);
 782         switch (expr->type) {
 783         case EXPR_CALL:
 784                 function_comparison(SPECIAL_NOTEQUAL, expr, 0, 1);
 785                 return;
 786         case EXPR_PREOP:
 787         case EXPR_SYMBOL:
 788         case EXPR_DEREF:
 789                 name = get_variable_from_expr(expr, &sym);
 790                 if (!name)
 791                         return;
 792                 pre_state = get_state(my_id, name, sym);
 793                 true_state = add_filter(pre_state, 0);
 794                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 795                         false_state = alloc_estate(0);
 796                 else
 797                         false_state = alloc_estate_empty();
 798                 set_extra_true_false(name, sym, true_state, false_state);
 799                 free_string(name);
 800                 return;
 801         case EXPR_COMPARE:
 802                 match_comparison(expr);
 803                 return;
 804         case EXPR_ASSIGNMENT:
 805                 __extra_match_condition(expr->left);
 806                 return;
 807         }
 808 }
 809
 810 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 811 int implied_not_equal(struct expression *expr, long long val)
 812 {
 813         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 814 }
 815
 816 int get_implied_range_list(struct expression *expr, struct range_list **rl)
 817 {
 818         long long val;
 819         struct smatch_state *state;
 820         long long min;
 821         long long max;
 822
 823         *rl = NULL;
 824
 825         expr = strip_parens(expr);
 826         if (!expr)
 827                 return 0;
 828
 829         state = get_state_expr(my_id, expr);
 830         if (state) {
 831                 *rl = clone_range_list(estate_ranges(state));
 832                 return 1;
 833         }
 834
 835         if (expr->type == EXPR_CALL) {
 836                 *rl = db_return_vals(expr);
 837                 return !!*rl;
 838         }
 839
 840         if (get_implied_value(expr, &val)) {
 841                 add_range(rl, val, val);
 842                 return 1;
 843         }
 844
 845         if (expr->type == EXPR_BINOP && expr->op == '%') {
 846                 if (!get_implied_value(expr->right, &val))
 847                         return 0;
 848                 add_range(rl, 0, val - 1);
 849                 return 1;
 850         }
 851
 852         if (!get_implied_min(expr, &min))
 853                 return 0;
 854         if (!get_implied_max(expr, &max))
 855                 return 0;
 856
 857         *rl = alloc_range_list(min, max);
 858         return 1;
 859 }
 860
 861 int is_whole_range(struct smatch_state *state)
 862 {
 863         return is_whole_range_rl(estate_ranges(state));
 864 }
 865
 866 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 867 {
 868         if (is_whole_range(state))
 869                 return;
 870         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 871 }
 872
 873 static void match_call_info(struct expression *expr)
 874 {
 875         struct range_list *rl = NULL;
 876         struct expression *arg;
 877         char *name;
 878         int i = 0;
 879
 880         name = get_fnptr_name(expr->fn);
 881         if (!name)
 882                 return;
 883
 884         FOR_EACH_PTR(expr->args, arg) {
 885                 if (get_implied_range_list(arg, &rl) && !is_whole_range_rl(rl)) {
 886                         sm_msg("info: passes param_value '%s' %d '$$' %s %s",
 887                                name, i, show_ranges(rl),
 888                                is_static(expr->fn) ? "static" : "global");
 889                 }
 890                 i++;
 891         } END_FOR_EACH_PTR(arg);
 892
 893         free_string(name);
 894 }
 895
 896 void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
 897 {
 898         struct range_list *rl = NULL;
 899         struct smatch_state *state;
 900         char fullname[256];
 901
 902         if (strncmp(key, "$$", 2))
 903                 return;
 904
 905         snprintf(fullname, 256, "%s%s", name, key + 2);
 906         get_value_ranges(value, &rl);
 907         char *tmp = show_ranges(rl);
 908         if (strcmp(tmp, value))
 909                 sm_msg("value = %s, ranges = %s", value, tmp);
 910         state = alloc_estate_range_list(rl);
 911         set_state(SMATCH_EXTRA, fullname, sym, state);
 912 }
 913
 914 static void match_call_assign(struct expression *expr)
 915 {
 916         struct expression *right;
 917         struct range_list *rl;
 918
 919         if (expr->op != '=')
 920                 return;
 921
 922         right = strip_parens(expr->right);
 923         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 924                 right = strip_parens(right->left);
 925
 926         rl = db_return_vals(right);
 927         if (rl)
 928                 set_extra_expr_mod(expr->left, alloc_estate_range_list(rl));
 929         else
 930                 set_extra_expr_mod(expr->left, extra_undefined());
 931 }
 932
 933 void register_smatch_extra(int id)
 934 {
 935         my_id = id;
 936
 937         alloc_estate_undefined();
 938         add_merge_hook(my_id, &merge_func);
 939         add_unmatched_state_hook(my_id, &unmatched_state);
 940         add_hook(&unop_expr, OP_HOOK);
 941         add_hook(&match_function_def, FUNC_DEF_HOOK);
 942         add_hook(&match_declarations, DECLARATION_HOOK);
 943         if (option_info) {
 944                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 945                 add_member_info_callback(my_id, struct_member_callback);
 946         }
 947         add_definition_db_callback(set_param_value, PARAM_VALUE);
 948 }
 949
 950 void register_smatch_extra_late(int id)
 951 {
 952         add_hook(&match_dereferences, DEREF_HOOK);
 953         add_hook(&match_pointer_as_array, OP_HOOK);
 954         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
 955         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
 956         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
 957         add_hook(&match_assign, ASSIGNMENT_HOOK);
 958         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
 959
 960 }