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