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 *rl)
 132 {
 133         struct range_list *res;
 134         struct data_range *tmp;
 135
 136         if (!orig)
 137                 orig = extra_undefined();
 138         res = estate_ranges(orig);
 139
 140         FOR_EACH_PTR(rl, tmp) {
 141                 res = remove_range(res, tmp->min, tmp->max);
 142         } END_FOR_EACH_PTR(tmp);
 143
 144         return alloc_estate_range_list(res);
 145 }
 146
 147 struct smatch_state *filter_range(struct smatch_state *orig,
 148                                  long long filter_min, long long filter_max)
 149 {
 150         struct range_list *rl;
 151
 152         if (!orig)
 153                 orig = extra_undefined();
 154
 155         rl = remove_range(estate_ranges(orig), filter_min, filter_max);
 156         return alloc_estate_range_list(rl);
 157 }
 158
 159 struct smatch_state *add_filter(struct smatch_state *orig, long long num)
 160 {
 161         return filter_range(orig, num, num);
 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 *value_ranges;
 168         struct related_list *rlist;
 169
 170         if (estates_equiv(s1, s2))
 171                 return s1;
 172
 173         value_ranges = range_list_union(estate_ranges(s1), estate_ranges(s2));
 174         tmp = alloc_estate_range_list(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         long long 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 (estate_min(sm->state) < 0)
 201                 return NULL;
 202         start = estate_max(sm->state);
 203         if  (start <= 0)
 204                 return NULL;
 205         if (start != whole_range.max)
 206                 start--;
 207
 208         if (condition->type == EXPR_PREOP)
 209                 set_extra_expr_mod(iter_var, alloc_estate_range(1, start));
 210         if (condition->type == EXPR_POSTOP)
 211                 set_extra_expr_mod(iter_var, alloc_estate_range(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         long long start;
 221         long long end;
 222
 223         iter_var = iter_expr->unop;
 224         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 225         if (!sm)
 226                 return NULL;
 227         if (!estate_get_single_value(sm->state, &start))
 228                 return NULL;
 229         if (!get_implied_value(condition->right, &end))
 230                 end = whole_range.max;
 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 (end != whole_range.max)
 238                         end--;
 239                 break;
 240         case SPECIAL_LTE:
 241                 break;
 242         default:
 243                 return NULL;
 244         }
 245         if (end < start)
 246                 return NULL;
 247         set_extra_expr_mod(iter_var, alloc_estate_range(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         long long start;
 257         long long end;
 258
 259         iter_var = iter_expr->unop;
 260         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 261         if (!sm)
 262                 return NULL;
 263         if (!estate_get_single_value(sm->state, &start))
 264                 return NULL;
 265         if (!get_implied_value(condition->right, &end))
 266                 end = whole_range.max;
 267         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 268                 return NULL;
 269
 270         switch (condition->op) {
 271         case SPECIAL_NOTEQUAL:
 272         case '>':
 273                 if (end != whole_range.min)
 274                         end++;
 275                 break;
 276         case SPECIAL_GTE:
 277                 break;
 278         default:
 279                 return NULL;
 280         }
 281         if (end > start)
 282                 return NULL;
 283         set_extra_expr_mod(iter_var, alloc_estate_range(end, start));
 284         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 285 }
 286
 287 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 288 {
 289         struct expression *iter_expr;
 290         struct expression *condition;
 291
 292         if (!loop->iterator_post_statement)
 293                 return NULL;
 294         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 295                 return NULL;
 296         iter_expr = loop->iterator_post_statement->expression;
 297         if (!loop->iterator_pre_condition)
 298                 return NULL;
 299         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 300                 return NULL;
 301         condition = loop->iterator_pre_condition;
 302
 303         if (iter_expr->op == SPECIAL_INCREMENT)
 304                 return handle_canonical_for_inc(iter_expr, condition);
 305         if (iter_expr->op == SPECIAL_DECREMENT)
 306                 return handle_canonical_for_dec(iter_expr, condition);
 307         return NULL;
 308 }
 309
 310 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 311 {
 312         struct sm_state *ret;
 313
 314         __push_fake_cur_slist();
 315         if (!loop->iterator_post_statement)
 316                 ret = handle_canonical_while_count_down(loop);
 317         else
 318                 ret = handle_canonical_for_loops(loop);
 319         *slist = __pop_fake_cur_slist();
 320         return ret;
 321 }
 322
 323 int __iterator_unchanged(struct sm_state *sm)
 324 {
 325         if (!sm)
 326                 return 0;
 327         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 328                 return 1;
 329         return 0;
 330 }
 331
 332 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 333 {
 334         long long after_value;
 335
 336         /* paranoid checking.  prolly not needed */
 337         condition = strip_expr(condition);
 338         if (!condition)
 339                 return;
 340         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 341                 return;
 342         if (condition->op != SPECIAL_DECREMENT)
 343                 return;
 344         after_value = estate_min(sm->state);
 345         after_value--;
 346         set_extra_mod(sm->name, sm->sym, alloc_estate(after_value));
 347 }
 348
 349 void __extra_pre_loop_hook_after(struct sm_state *sm,
 350                                 struct statement *iterator,
 351                                 struct expression *condition)
 352 {
 353         struct expression *iter_expr;
 354         char *name;
 355         struct symbol *sym;
 356         long long value;
 357         int left = 0;
 358         struct smatch_state *state;
 359         long long min, max;
 360
 361         if (!iterator) {
 362                 while_count_down_after(sm, condition);
 363                 return;
 364         }
 365
 366         iter_expr = iterator->expression;
 367
 368         if (condition->type != EXPR_COMPARE)
 369                 return;
 370         if (!get_value(condition->left, &value)) {
 371                 if (!get_value(condition->right, &value))
 372                         return;
 373                 left = 1;
 374         }
 375         if (left)
 376                 name = get_variable_from_expr(condition->left, &sym);
 377         else
 378                 name = get_variable_from_expr(condition->right, &sym);
 379         if (!name || !sym)
 380                 goto free;
 381         if (sym != sm->sym || strcmp(name, sm->name))
 382                 goto free;
 383         state = get_state(my_id, name, sym);
 384         min = estate_min(state);
 385         max = estate_max(state);
 386         if (iter_expr->op == SPECIAL_INCREMENT &&
 387                 min != whole_range.min &&
 388                 max == whole_range.max) {
 389                 set_extra_mod(name, sym, alloc_estate(min));
 390         } else if (min == whole_range.min && max != whole_range.max) {
 391                 set_extra_mod(name, sym, alloc_estate(max));
 392         }
 393 free:
 394         free_string(name);
 395         return;
 396 }
 397
 398 static struct smatch_state *unmatched_state(struct sm_state *sm)
 399 {
 400         return extra_undefined();
 401 }
 402
 403 static void match_function_call(struct expression *expr)
 404 {
 405         struct expression *arg;
 406         struct expression *tmp;
 407
 408         FOR_EACH_PTR(expr->args, arg) {
 409                 tmp = strip_expr(arg);
 410                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 411                         remove_from_equiv_expr(tmp->unop);
 412                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined());
 413                 }
 414         } END_FOR_EACH_PTR(arg);
 415 }
 416
 417 static void match_assign(struct expression *expr)
 418 {
 419         struct expression *left;
 420         struct expression *right;
 421         struct symbol *right_sym;
 422         char *right_name;
 423         struct symbol *sym;
 424         char *name;
 425         long long value;
 426         int known;
 427         long long min = whole_range.min;
 428         long long max = whole_range.max;
 429         long long tmp;
 430
 431         if (__is_condition_assign(expr))
 432                 return;
 433         left = strip_expr(expr->left);
 434         name = get_variable_from_expr(left, &sym);
 435         if (!name)
 436                 return;
 437         right = strip_parens(expr->right);
 438         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 439                 right = strip_parens(right->left);
 440
 441         if (expr->op == '=' && right->type == EXPR_CALL)
 442                 return;  /* these are handled in match_call_assign() */
 443
 444         right_name = get_variable_from_expr(right, &right_sym);
 445         if (expr->op == '=' && right_name && right_sym) {
 446                 set_equiv(left, right);
 447                 goto free;
 448         }
 449
 450         known = get_implied_value(right, &value);
 451         switch (expr->op) {
 452         case '=': {
 453                 struct range_list *rl = NULL;
 454
 455                 if (get_implied_range_list(right, &rl)) {
 456                         set_extra_mod(name, sym, alloc_estate_range_list(rl));
 457                         goto free;
 458                 }
 459
 460                 if (expr_unsigned(right))
 461                         min = 0;
 462                 break;
 463         }
 464         case SPECIAL_ADD_ASSIGN:
 465                 if (get_implied_min(left, &tmp)) {
 466                         if (known)
 467                                 min = tmp + value;
 468                         else
 469                                 min = tmp;
 470                 }
 471                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 472                                 max = tmp + value;
 473                 break;
 474         case SPECIAL_SUB_ASSIGN:
 475                 if (get_implied_max(left, &tmp)) {
 476                         if (known)
 477                                 max = tmp - value;
 478                         else
 479                                 max = tmp;
 480                 }
 481                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 482                                 min = tmp - value;
 483                 break;
 484         }
 485         set_extra_mod(name, sym, alloc_estate_range(min, max));
 486 free:
 487         free_string(right_name);
 488         free_string(name);
 489 }
 490
 491 static void reset_struct_members(struct sm_state *sm)
 492 {
 493         set_extra_mod(sm->name, sm->sym, extra_undefined());
 494 }
 495
 496 static struct smatch_state *increment_state(struct smatch_state *state)
 497 {
 498         long long min = estate_min(state);
 499         long long max = estate_max(state);
 500
 501         if (inside_loop())
 502                 max = whole_range.max;
 503
 504         if (min != whole_range.min)
 505                 min++;
 506         if (max != whole_range.max)
 507                 max++;
 508         return alloc_estate_range(min, max);
 509 }
 510
 511 static struct smatch_state *decrement_state(struct smatch_state *state)
 512 {
 513         long long min = estate_min(state);
 514         long long max = estate_max(state);
 515
 516         if (inside_loop())
 517                 min = whole_range.min;
 518
 519         if (min != whole_range.min)
 520                 min--;
 521         if (max != whole_range.max)
 522                 max--;
 523         return alloc_estate_range(min, max);
 524 }
 525
 526 static void unop_expr(struct expression *expr)
 527 {
 528         struct smatch_state *state;
 529
 530         if (expr->smatch_flags & Handled)
 531                 return;
 532
 533         switch (expr->op) {
 534         case SPECIAL_INCREMENT:
 535                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 536                 state = increment_state(state);
 537                 set_extra_expr_mod(expr->unop, state);
 538                 break;
 539         case SPECIAL_DECREMENT:
 540                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 541                 state = decrement_state(state);
 542                 set_extra_expr_mod(expr->unop, state);
 543                 break;
 544         default:
 545                 return;
 546         }
 547 }
 548
 549 static void asm_expr(struct statement *stmt)
 550 {
 551
 552         struct expression *expr;
 553         int state = 0;
 554
 555         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 556                 switch (state) {
 557                 case 0: /* identifier */
 558                 case 1: /* constraint */
 559                         state++;
 560                         continue;
 561                 case 2: /* expression */
 562                         state = 0;
 563                         set_extra_expr_mod(expr, extra_undefined());
 564                         continue;
 565                 }
 566         } END_FOR_EACH_PTR(expr);
 567 }
 568
 569 static void delete_state_tracker(struct tracker *t)
 570 {
 571         remove_from_equiv(t->name, t->sym);
 572         delete_state(t->owner, t->name, t->sym);
 573 }
 574
 575 static void scoped_state_extra(const char *name, struct symbol *sym)
 576 {
 577         struct tracker *t;
 578
 579         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 580         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 581 }
 582
 583 static void match_declarations(struct symbol *sym)
 584 {
 585         const char *name;
 586
 587         if (sym->ident) {
 588                 name = sym->ident->name;
 589                 if (!sym->initializer) {
 590                         set_state(SMATCH_EXTRA, name, sym, extra_undefined());
 591                         scoped_state_extra(name, sym);
 592                 }
 593         }
 594 }
 595
 596 static void check_dereference(struct expression *expr)
 597 {
 598         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min, valid_ptr_max));
 599 }
 600
 601 static void match_dereferences(struct expression *expr)
 602 {
 603         if (expr->type != EXPR_PREOP)
 604                 return;
 605         check_dereference(expr->unop);
 606 }
 607
 608 static void match_pointer_as_array(struct expression *expr)
 609 {
 610         if (!is_array(expr))
 611                 return;
 612         check_dereference(expr->unop->left);
 613 }
 614
 615 static void set_param_dereferenced(struct expression *arg, char *unused)
 616 {
 617         check_dereference(arg);
 618 }
 619
 620 static void match_function_def(struct symbol *sym)
 621 {
 622         struct symbol *arg;
 623
 624         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 625                 if (!arg->ident)
 626                         continue;
 627                 set_state(my_id, arg->ident->name, arg, extra_undefined());
 628         } END_FOR_EACH_PTR(arg);
 629 }
 630
 631 static int match_func_comparison(struct expression *expr)
 632 {
 633         struct expression *left = strip_expr(expr->left);
 634         struct expression *right = strip_expr(expr->right);
 635         long long val;
 636
 637         if (left->type == EXPR_CALL) {
 638                 if (!get_implied_value(right, &val))
 639                         return 1;
 640                 function_comparison(expr->op, left, val, 1);
 641                 return 1;
 642         }
 643
 644         if (right->type == EXPR_CALL) {
 645                 if (!get_implied_value(left, &val))
 646                         return 1;
 647                 function_comparison(expr->op, right, val, 0);
 648                 return 1;
 649         }
 650
 651         return 0;
 652 }
 653
 654 static void match_comparison(struct expression *expr)
 655 {
 656         struct expression *left = strip_expr(expr->left);
 657         struct expression *right = strip_expr(expr->right);
 658         struct range_list *left_orig;
 659         struct range_list *left_true;
 660         struct range_list *left_false;
 661         struct range_list *right_orig;
 662         struct range_list *right_true;
 663         struct range_list *right_false;
 664         struct smatch_state *left_true_state;
 665         struct smatch_state *left_false_state;
 666         struct smatch_state *right_true_state;
 667         struct smatch_state *right_false_state;
 668         int left_postop = 0;
 669         int right_postop = 0;
 670
 671         if (match_func_comparison(expr))
 672                 return;
 673
 674         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 675                 if (left->type == EXPR_POSTOP) {
 676                         left->smatch_flags |= Handled;
 677                         left_postop = left->op;
 678                 }
 679                 left = strip_expr(left->unop);
 680         }
 681
 682         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 683                 if (right->type == EXPR_POSTOP) {
 684                         right->smatch_flags |= Handled;
 685                         right_postop = right->op;
 686                 }
 687                 right = strip_expr(right->unop);
 688         }
 689
 690         if (!get_implied_range_list(left, &left_orig))
 691                 left_orig = alloc_range_list(whole_range.min, whole_range.max);
 692         if (!get_implied_range_list(right, &right_orig))
 693                 right_orig = alloc_range_list(whole_range.min, whole_range.max);
 694
 695         left_true = clone_range_list(left_orig);
 696         left_false = clone_range_list(left_orig);
 697         right_true = clone_range_list(right_orig);
 698         right_false = clone_range_list(right_orig);
 699
 700         switch (expr->op) {
 701         case '<':
 702         case SPECIAL_UNSIGNED_LT:
 703                 if (rl_max(right_orig) != whole_range.max)
 704                         left_true = remove_range(left_orig, rl_max(right_orig), whole_range.max);
 705                 if (rl_min(right_orig) != whole_range.min)
 706                         left_false = remove_range(left_orig, whole_range.min, rl_min(right_orig) - 1);
 707
 708                 if (rl_min(left_orig) != whole_range.min)
 709                         right_true = remove_range(right_orig, whole_range.min, rl_min(left_orig));
 710                 if (rl_max(left_orig) != whole_range.max)
 711                         right_false = remove_range(right_orig, rl_max(left_orig) + 1, whole_range.max);
 712                 break;
 713         case SPECIAL_UNSIGNED_LTE:
 714         case SPECIAL_LTE:
 715                 if (rl_max(right_orig) != whole_range.max)
 716                         left_true = remove_range(left_orig, rl_max(right_orig) + 1, whole_range.max);
 717                 if (rl_min(right_orig) != whole_range.min)
 718                         left_false = remove_range(left_orig, whole_range.min, rl_min(right_orig));
 719
 720                 if (rl_min(left_orig) != whole_range.min)
 721                         right_true = remove_range(right_orig, whole_range.min, rl_min(left_orig) - 1);
 722                 if (rl_max(left_orig) != whole_range.max)
 723                         right_false = remove_range(right_orig, rl_max(left_orig), whole_range.max);
 724                 break;
 725         case SPECIAL_EQUAL:
 726                 if (rl_max(right_orig) != whole_range.max)
 727                         left_true = remove_range(left_true, rl_max(right_orig) + 1, whole_range.max);
 728                 if (rl_min(right_orig) != whole_range.min)
 729                         left_true = remove_range(left_true, whole_range.min, rl_min(right_orig) - 1);
 730                 if (rl_min(right_orig) == rl_max(right_orig))
 731                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 732
 733                 if (rl_max(left_orig) != whole_range.max)
 734                         right_true = remove_range(right_true, rl_max(left_orig) + 1, whole_range.max);
 735                 if (rl_min(left_orig) != whole_range.min)
 736                         right_true = remove_range(right_true, whole_range.min, rl_min(left_orig) - 1);
 737                 if (rl_min(left_orig) == rl_max(left_orig))
 738                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 739                 break;
 740         case SPECIAL_UNSIGNED_GTE:
 741         case SPECIAL_GTE:
 742                 if (rl_min(right_orig) != whole_range.min)
 743                         left_true = remove_range(left_orig, whole_range.min, rl_min(right_orig) - 1);
 744                 if (rl_max(right_orig) != whole_range.max)
 745                         left_false = remove_range(left_orig, rl_max(right_orig), whole_range.max);
 746
 747                 if (rl_max(left_orig) != whole_range.max)
 748                         right_true = remove_range(right_orig, rl_max(left_orig) + 1, whole_range.max);
 749                 if (rl_min(left_orig) != whole_range.min)
 750                         right_false = remove_range(right_orig, whole_range.min, rl_min(left_orig));
 751                 break;
 752         case '>':
 753         case SPECIAL_UNSIGNED_GT:
 754                 if (rl_min(right_orig) != whole_range.min)
 755                         left_true = remove_range(left_orig, whole_range.min, rl_min(right_orig));
 756                 if (rl_max(right_orig) != whole_range.max)
 757                         left_false = remove_range(left_orig, rl_max(right_orig) + 1, whole_range.max);
 758
 759                 if (rl_max(left_orig) != whole_range.max)
 760                         right_true = remove_range(right_orig, rl_max(left_orig), whole_range.max);
 761                 if (rl_min(left_orig) != whole_range.min)
 762                         right_false = remove_range(right_orig, whole_range.min, rl_min(left_orig) - 1);
 763                 break;
 764         case SPECIAL_NOTEQUAL:
 765                 if (rl_max(right_orig) != whole_range.max)
 766                         left_false = remove_range(left_false, rl_max(right_orig) + 1, whole_range.max);
 767                 if (rl_min(right_orig) != whole_range.min)
 768                         left_false = remove_range(left_false, whole_range.min, rl_min(right_orig) - 1);
 769                 if (rl_min(right_orig) == rl_max(right_orig))
 770                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 771
 772                 if (rl_max(left_orig) != whole_range.max)
 773                         right_false = remove_range(right_false, rl_max(left_orig) + 1, whole_range.max);
 774                 if (rl_min(left_orig) != whole_range.min)
 775                         right_false = remove_range(right_false, whole_range.min, rl_min(left_orig) - 1);
 776                 if (rl_min(left_orig) == rl_max(left_orig))
 777                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 778                 break;
 779         default:
 780                 return;
 781         }
 782
 783         left_true_state = alloc_estate_range_list(left_true);
 784         left_false_state = alloc_estate_range_list(left_false);
 785         right_true_state = alloc_estate_range_list(right_true);
 786         right_false_state = alloc_estate_range_list(right_false);
 787
 788         if (left_postop == SPECIAL_INCREMENT) {
 789                 left_true_state = increment_state(left_true_state);
 790                 left_false_state = increment_state(left_false_state);
 791         }
 792         if (left_postop == SPECIAL_DECREMENT) {
 793                 left_true_state = decrement_state(left_true_state);
 794                 left_false_state = decrement_state(left_false_state);
 795         }
 796         if (right_postop == SPECIAL_INCREMENT) {
 797                 right_true_state = increment_state(right_true_state);
 798                 right_false_state = increment_state(right_false_state);
 799         }
 800         if (right_postop == SPECIAL_DECREMENT) {
 801                 right_true_state = decrement_state(right_true_state);
 802                 right_false_state = decrement_state(right_false_state);
 803         }
 804
 805         set_extra_expr_true_false(left, left_true_state, left_false_state);
 806         set_extra_expr_true_false(right, right_true_state, right_false_state);
 807 }
 808
 809 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 810 void __extra_match_condition(struct expression *expr)
 811 {
 812         struct symbol *sym;
 813         char *name;
 814         struct smatch_state *pre_state;
 815         struct smatch_state *true_state;
 816         struct smatch_state *false_state;
 817
 818         expr = strip_expr(expr);
 819         switch (expr->type) {
 820         case EXPR_CALL:
 821                 function_comparison(SPECIAL_NOTEQUAL, expr, 0, 1);
 822                 return;
 823         case EXPR_PREOP:
 824         case EXPR_SYMBOL:
 825         case EXPR_DEREF:
 826                 name = get_variable_from_expr(expr, &sym);
 827                 if (!name)
 828                         return;
 829                 pre_state = get_state(my_id, name, sym);
 830                 true_state = add_filter(pre_state, 0);
 831                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 832                         false_state = alloc_estate(0);
 833                 else
 834                         false_state = alloc_estate_empty();
 835                 set_extra_true_false(name, sym, true_state, false_state);
 836                 free_string(name);
 837                 return;
 838         case EXPR_COMPARE:
 839                 match_comparison(expr);
 840                 return;
 841         case EXPR_ASSIGNMENT:
 842                 __extra_match_condition(expr->left);
 843                 return;
 844         }
 845 }
 846
 847 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 848 int implied_not_equal(struct expression *expr, long long val)
 849 {
 850         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 851 }
 852
 853 int get_implied_range_list(struct expression *expr, struct range_list **rl)
 854 {
 855         long long val;
 856         struct smatch_state *state;
 857         long long min;
 858         long long max;
 859
 860         *rl = NULL;
 861
 862         expr = strip_parens(expr);
 863         if (!expr)
 864                 return 0;
 865
 866         state = get_state_expr(my_id, expr);
 867         if (state) {
 868                 *rl = clone_range_list(estate_ranges(state));
 869                 goto out;
 870         }
 871
 872         if (expr->type == EXPR_CALL) {
 873                 if (get_implied_return(expr, rl))
 874                         goto out;
 875                 *rl = db_return_vals(expr);
 876                 goto out;
 877         }
 878
 879         if (get_implied_value(expr, &val)) {
 880                 add_range(rl, val, val);
 881                 goto out;
 882         }
 883
 884         if (expr->type == EXPR_BINOP && expr->op == '%') {
 885                 if (!get_implied_value(expr->right, &val))
 886                         return 0;
 887                 add_range(rl, 0, val - 1);
 888                 goto out;
 889         }
 890
 891         if (!get_implied_min(expr, &min))
 892                 return 0;
 893         if (!get_implied_max(expr, &max))
 894                 return 0;
 895
 896         *rl = alloc_range_list(min, max);
 897
 898 out:
 899         if (is_whole_range_rl(*rl))
 900                 return 0;
 901         return 1;
 902 }
 903
 904 int is_whole_range(struct smatch_state *state)
 905 {
 906         return is_whole_range_rl(estate_ranges(state));
 907 }
 908
 909 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 910 {
 911         if (is_whole_range(state))
 912                 return;
 913         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 914 }
 915
 916 static void match_call_info(struct expression *expr)
 917 {
 918         struct range_list *rl = NULL;
 919         struct expression *arg;
 920         char *name;
 921         int i = 0;
 922
 923         name = get_fnptr_name(expr->fn);
 924         if (!name)
 925                 return;
 926
 927         FOR_EACH_PTR(expr->args, arg) {
 928                 if (get_implied_range_list(arg, &rl) && !is_whole_range_rl(rl)) {
 929                         sm_msg("info: passes param_value '%s' %d '$$' %s %s",
 930                                name, i, show_ranges(rl),
 931                                is_static(expr->fn) ? "static" : "global");
 932                 }
 933                 i++;
 934         } END_FOR_EACH_PTR(arg);
 935
 936         free_string(name);
 937 }
 938
 939 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
 940 {
 941         struct range_list *rl = NULL;
 942         struct smatch_state *state;
 943         char fullname[256];
 944
 945         if (strncmp(key, "$$", 2))
 946                 return;
 947
 948         snprintf(fullname, 256, "%s%s", name, key + 2);
 949         get_value_ranges(value, &rl);
 950         state = alloc_estate_range_list(rl);
 951         set_state(SMATCH_EXTRA, fullname, sym, state);
 952 }
 953
 954 static void match_call_assign(struct expression *expr)
 955 {
 956         if (expr->op != '=')
 957                 return;
 958
 959         /* if we have a db set up this gets set in smatch_function_hooks.c */
 960         if (option_no_db)
 961                 set_extra_expr_mod(expr->left, extra_undefined());
 962 }
 963
 964 void register_smatch_extra(int id)
 965 {
 966         my_id = id;
 967
 968         alloc_estate_undefined();
 969         add_merge_hook(my_id, &merge_func);
 970         add_unmatched_state_hook(my_id, &unmatched_state);
 971         add_hook(&unop_expr, OP_HOOK);
 972         add_hook(&asm_expr, ASM_HOOK);
 973         add_hook(&match_function_def, FUNC_DEF_HOOK);
 974         add_hook(&match_declarations, DECLARATION_HOOK);
 975         if (option_info) {
 976                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 977                 add_member_info_callback(my_id, struct_member_callback);
 978         }
 979         add_definition_db_callback(set_param_value, PARAM_VALUE);
 980 }
 981
 982 void register_smatch_extra_late(int id)
 983 {
 984         add_hook(&match_dereferences, DEREF_HOOK);
 985         add_hook(&match_pointer_as_array, OP_HOOK);
 986         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
 987         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
 988         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
 989         add_hook(&match_assign, ASSIGNMENT_HOOK);
 990         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
 991 }