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