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