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(struct smatch_state *orig,
 131                                  sval_t filter_min, sval_t filter_max)
 132 {
 133         struct range_list_sval *rl;
 134
 135         if (!orig)
 136                 orig = extra_undefined(filter_min.type);
 137
 138         rl = remove_range_sval(estate_ranges_sval(orig), filter_min, filter_max);
 139         return alloc_estate_range_list_sval(rl);
 140 }
 141
 142 struct smatch_state *add_filter(struct smatch_state *orig, sval_t sval)
 143 {
 144         return filter_range(orig, sval, sval);
 145 }
 146
 147 static struct smatch_state *merge_func(struct smatch_state *s1, struct smatch_state *s2)
 148 {
 149         struct smatch_state *tmp;
 150         struct range_list_sval *value_ranges;
 151         struct related_list *rlist;
 152
 153         if (estates_equiv(s1, s2))
 154                 return s1;
 155
 156         value_ranges = range_list_union_sval(estate_ranges_sval(s1), estate_ranges_sval(s2));
 157         tmp = alloc_estate_range_list_sval(value_ranges);
 158         rlist = get_shared_relations(estate_related(s1), estate_related(s2));
 159         set_related(&tmp, rlist);
 160
 161         return tmp;
 162 }
 163
 164 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 165 {
 166         struct expression *iter_var;
 167         struct expression *condition;
 168         struct sm_state *sm;
 169         sval_t start;
 170
 171         condition = strip_expr(loop->iterator_pre_condition);
 172         if (!condition)
 173                 return NULL;
 174         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 175                 return NULL;
 176         if (condition->op != SPECIAL_DECREMENT)
 177                 return NULL;
 178
 179         iter_var = condition->unop;
 180         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 181         if (!sm)
 182                 return NULL;
 183         if (sval_cmp_val(estate_min_sval(sm->state), 0) < 0)
 184                 return NULL;
 185         start = estate_max_sval(sm->state);
 186         if  (sval_cmp_val(start, 0) <= 0)
 187                 return NULL;
 188         if (!sval_is_max(start))
 189                 start.value--;
 190
 191         if (condition->type == EXPR_PREOP)
 192                 set_extra_expr_mod(iter_var, alloc_estate_range_sval(ll_to_sval(1), start));
 193         if (condition->type == EXPR_POSTOP)
 194                 set_extra_expr_mod(iter_var, alloc_estate_range_sval(ll_to_sval(0), start));
 195         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 196 }
 197
 198 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 199                                                 struct expression *condition)
 200 {
 201         struct expression *iter_var;
 202         struct sm_state *sm;
 203         sval_t start, 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_sval(sm->state, &start))
 210                 return NULL;
 211         if (!get_implied_value_sval(condition->right, &end))
 212                 end = sval_type_max(get_type(iter_var));
 213
 214         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 215                 return NULL;
 216
 217         switch (condition->op) {
 218         case SPECIAL_NOTEQUAL:
 219         case '<':
 220                 if (!sval_is_max(end))
 221                         end.value--;
 222                 break;
 223         case SPECIAL_LTE:
 224                 break;
 225         default:
 226                 return NULL;
 227         }
 228         if (sval_cmp(end, start) < 0)
 229                 return NULL;
 230         set_extra_expr_mod(iter_var, alloc_estate_range_sval(start, end));
 231         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 232 }
 233
 234 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 235                                                 struct expression *condition)
 236 {
 237         struct expression *iter_var;
 238         struct sm_state *sm;
 239         sval_t start, 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_sval(sm->state, &start))
 246                 return NULL;
 247         if (!get_implied_value_sval(condition->right, &end))
 248                 end = sval_type_min(get_type(iter_var));
 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 (!sval_is_min(end) && !sval_is_max(end))
 256                         end.value++;
 257                 break;
 258         case SPECIAL_GTE:
 259                 break;
 260         default:
 261                 return NULL;
 262         }
 263         if (sval_cmp(end, start) > 0)
 264                 return NULL;
 265         set_extra_expr_mod(iter_var, alloc_estate_range_sval(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         sval_t 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_sval(sm->state);
 327         after_value.value--;
 328         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(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         sval_t value;
 339         int left = 0;
 340         struct smatch_state *state;
 341         sval_t 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_sval(condition->left, &value)) {
 353                 if (!get_value_sval(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_sval(state);
 367         max = estate_max_sval(state);
 368         if (iter_expr->op == SPECIAL_INCREMENT &&
 369             !sval_is_min(min) && sval_is_max(max))
 370                 set_extra_mod(name, sym, alloc_estate_sval(min));
 371         else if (sval_is_min(min) && !sval_is_max(max))
 372                 set_extra_mod(name, sym, alloc_estate_sval(max));
 373
 374 free:
 375         free_string(name);
 376         return;
 377 }
 378
 379 static struct smatch_state *unmatched_state(struct sm_state *sm)
 380 {
 381         return extra_undefined(estate_type(sm->state));
 382 }
 383
 384 static void match_function_call(struct expression *expr)
 385 {
 386         struct expression *arg;
 387         struct expression *tmp;
 388
 389         FOR_EACH_PTR(expr->args, arg) {
 390                 tmp = strip_expr(arg);
 391                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 392                         remove_from_equiv_expr(tmp->unop);
 393                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined(get_type(tmp->unop)));
 394                 }
 395         } END_FOR_EACH_PTR(arg);
 396 }
 397
 398 static void match_assign(struct expression *expr)
 399 {
 400         struct range_list_sval *rl = NULL;
 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         sval_t value;
 408         int known;
 409         sval_t right_min, right_max;
 410         sval_t tmp;
 411
 412         if (__is_condition_assign(expr))
 413                 return;
 414         left = strip_expr(expr->left);
 415         name = get_variable_from_expr(left, &sym);
 416         if (!name)
 417                 return;
 418         right = strip_parens(expr->right);
 419         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 420                 right = strip_parens(right->left);
 421
 422         if (expr->op == '=' && right->type == EXPR_CALL)
 423                 return;  /* these are handled in match_call_assign() */
 424
 425         right_name = get_variable_from_expr(right, &right_sym);
 426         if (expr->op == '=' && right_name && right_sym &&
 427             types_equiv(get_type(expr->left), get_type(expr->right))) {
 428                 set_equiv(left, right);
 429                 goto free;
 430         }
 431
 432         right_min = sval_type_min(get_type(expr->right));
 433         right_max = sval_type_max(get_type(expr->right));
 434
 435         known = get_implied_value_sval(right, &value);
 436         switch (expr->op) {
 437         case '=': {
 438                 if (get_implied_range_list_sval(right, &rl)) {
 439                         rl = cast_rl(rl, get_type(expr->left));
 440                         set_extra_mod(name, sym, alloc_estate_range_list_sval(rl));
 441                         goto free;
 442                 }
 443
 444                 break;
 445         }
 446         case SPECIAL_ADD_ASSIGN:
 447                 if (get_implied_min_sval(left, &tmp)) {
 448                         if (known)
 449                                 right_min = sval_binop(tmp, '+', value);
 450                         else
 451                                 right_min = tmp;
 452                 }
 453                 if (!inside_loop() && known && get_implied_max_sval(left, &tmp))
 454                         right_max = sval_binop(tmp, '+', value);
 455                 break;
 456         case SPECIAL_SUB_ASSIGN:
 457                 if (get_implied_max_sval(left, &tmp)) {
 458                         if (known)
 459                                 right_max = sval_binop(tmp, '-', value);
 460                         else
 461                                 right_max = tmp;
 462                 }
 463                 if (!inside_loop() && known && get_implied_min_sval(left, &tmp))
 464                         right_min = sval_binop(tmp, '-', value);
 465                 break;
 466         }
 467         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 468                 rl = cast_rl(alloc_range_list_sval(right_min, right_max), get_type(expr->left));
 469         else
 470                 rl = whole_range_list_sval(get_type(expr->left));
 471         set_extra_mod(name, sym, alloc_estate_range_list_sval(rl));
 472 free:
 473         free_string(right_name);
 474         free_string(name);
 475 }
 476
 477 static void reset_struct_members(struct sm_state *sm)
 478 {
 479         set_extra_mod(sm->name, sm->sym, extra_undefined(estate_type(sm->state)));
 480 }
 481
 482 static struct smatch_state *increment_state(struct smatch_state *state)
 483 {
 484         sval_t min = estate_min_sval(state);
 485         sval_t max = estate_max_sval(state);
 486
 487         if (inside_loop())
 488                 max = sval_type_max(max.type);
 489
 490         if (!sval_is_min(min))
 491                 min.value++;
 492         if (!sval_is_max(max))
 493                 max.value++;
 494         return alloc_estate_range_sval(min, max);
 495 }
 496
 497 static struct smatch_state *decrement_state(struct smatch_state *state)
 498 {
 499         sval_t min = estate_min_sval(state);
 500         sval_t max = estate_max_sval(state);
 501
 502         if (inside_loop())
 503                 min = sval_type_min(min.type);
 504
 505         if (!sval_is_min(min))
 506                 min.value--;
 507         if (!sval_is_max(max))
 508                 max.value--;
 509         return alloc_estate_range_sval(min, max);
 510 }
 511
 512 static void unop_expr(struct expression *expr)
 513 {
 514         struct smatch_state *state;
 515
 516         if (expr->smatch_flags & Handled)
 517                 return;
 518
 519         switch (expr->op) {
 520         case SPECIAL_INCREMENT:
 521                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 522                 state = increment_state(state);
 523                 set_extra_expr_mod(expr->unop, state);
 524                 break;
 525         case SPECIAL_DECREMENT:
 526                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 527                 state = decrement_state(state);
 528                 set_extra_expr_mod(expr->unop, state);
 529                 break;
 530         default:
 531                 return;
 532         }
 533 }
 534
 535 static void asm_expr(struct statement *stmt)
 536 {
 537
 538         struct expression *expr;
 539         int state = 0;
 540
 541         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 542                 switch (state) {
 543                 case 0: /* identifier */
 544                 case 1: /* constraint */
 545                         state++;
 546                         continue;
 547                 case 2: /* expression */
 548                         state = 0;
 549                         set_extra_expr_mod(expr, extra_undefined(get_type(expr)));
 550                         continue;
 551                 }
 552         } END_FOR_EACH_PTR(expr);
 553 }
 554
 555 static void delete_state_tracker(struct tracker *t)
 556 {
 557         remove_from_equiv(t->name, t->sym);
 558         delete_state(t->owner, t->name, t->sym);
 559 }
 560
 561 static void scoped_state_extra(const char *name, struct symbol *sym)
 562 {
 563         struct tracker *t;
 564
 565         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 566         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 567 }
 568
 569 static void match_declarations(struct symbol *sym)
 570 {
 571         const char *name;
 572
 573         if (sym->ident) {
 574                 name = sym->ident->name;
 575                 if (!sym->initializer) {
 576                         set_state(SMATCH_EXTRA, name, sym, extra_undefined(get_real_base_type(sym)));
 577                         scoped_state_extra(name, sym);
 578                 }
 579         }
 580 }
 581
 582 static void check_dereference(struct expression *expr)
 583 {
 584         set_extra_expr_nomod(expr, alloc_estate_range_sval(valid_ptr_min_sval, valid_ptr_max_sval));
 585 }
 586
 587 static void match_dereferences(struct expression *expr)
 588 {
 589         if (expr->type != EXPR_PREOP)
 590                 return;
 591         check_dereference(expr->unop);
 592 }
 593
 594 static void match_pointer_as_array(struct expression *expr)
 595 {
 596         if (!is_array(expr))
 597                 return;
 598         check_dereference(expr->unop->left);
 599 }
 600
 601 static void set_param_dereferenced(struct expression *arg, char *unused)
 602 {
 603         check_dereference(arg);
 604 }
 605
 606 static void match_function_def(struct symbol *sym)
 607 {
 608         struct symbol *arg;
 609
 610         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 611                 if (!arg->ident)
 612                         continue;
 613                 set_state(my_id, arg->ident->name, arg, extra_undefined(get_real_base_type(arg)));
 614         } END_FOR_EACH_PTR(arg);
 615 }
 616
 617 static int match_func_comparison(struct expression *expr)
 618 {
 619         struct expression *left = strip_expr(expr->left);
 620         struct expression *right = strip_expr(expr->right);
 621         sval_t sval;
 622
 623         if (left->type == EXPR_CALL) {
 624                 if (!get_implied_value_sval(right, &sval))
 625                         return 1;
 626                 function_comparison(expr->op, left, sval, 1);
 627                 return 1;
 628         }
 629
 630         if (right->type == EXPR_CALL) {
 631                 if (!get_implied_value_sval(left, &sval))
 632                         return 1;
 633                 function_comparison(expr->op, right, sval, 0);
 634                 return 1;
 635         }
 636
 637         return 0;
 638 }
 639
 640 static sval_t add_one(sval_t sval)
 641 {
 642         sval.value++;
 643         return sval;
 644 }
 645
 646 static sval_t sub_one(sval_t sval)
 647 {
 648         sval.value--;
 649         return sval;
 650 }
 651
 652 static void match_comparison(struct expression *expr)
 653 {
 654         struct expression *left = strip_expr(expr->left);
 655         struct expression *right = strip_expr(expr->right);
 656         struct symbol *type;
 657         struct range_list_sval *left_orig;
 658         struct range_list_sval *left_true;
 659         struct range_list_sval *left_false;
 660         struct range_list_sval *right_orig;
 661         struct range_list_sval *right_true;
 662         struct range_list_sval *right_false;
 663         struct smatch_state *left_true_state;
 664         struct smatch_state *left_false_state;
 665         struct smatch_state *right_true_state;
 666         struct smatch_state *right_false_state;
 667         sval_t min, max;
 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         type = get_type(expr);
 691         if (!type) {
 692                 sm_msg("debug: failed to get type for '%s'", get_variable_from_expr_complex(expr, NULL));
 693                 type = &int_ctype;
 694         }
 695         min = sval_type_min(type);
 696         max = sval_type_max(type);
 697         if (get_implied_range_list_sval(left, &left_orig))
 698                 left_orig = cast_rl(left_orig, type);
 699         else
 700                 left_orig = alloc_range_list_sval(min, max);
 701
 702         if (get_implied_range_list_sval(right, &right_orig))
 703                 right_orig = cast_rl(right_orig, type);
 704         else
 705                 right_orig = alloc_range_list_sval(min, max);
 706
 707         left_true = clone_range_list_sval(left_orig);
 708         left_false = clone_range_list_sval(left_orig);
 709         right_true = clone_range_list_sval(right_orig);
 710         right_false = clone_range_list_sval(right_orig);
 711
 712         switch (expr->op) {
 713         case '<':
 714         case SPECIAL_UNSIGNED_LT:
 715                 if (!sval_is_max(rl_max_sval(right_orig))) {
 716                         left_true = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 717                 }
 718                 if (!sval_is_min(rl_min_sval(right_orig))) {
 719                         left_false = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 720                 }
 721
 722                 if (!sval_is_min(rl_min_sval(left_orig)))
 723                         right_true = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 724                 if (!sval_is_max(rl_max_sval(left_orig)))
 725                         right_false = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 726                 break;
 727         case SPECIAL_UNSIGNED_LTE:
 728         case SPECIAL_LTE:
 729                 if (!sval_is_max(rl_max_sval(right_orig)))
 730                         left_true = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 731                 if (!sval_is_min(rl_min_sval(right_orig)))
 732                         left_false = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 733
 734                 if (!sval_is_min(rl_min_sval(left_orig)))
 735                         right_true = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 736                 if (!sval_is_max(rl_max_sval(left_orig)))
 737                         right_false = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 738                 break;
 739         case SPECIAL_EQUAL:
 740                 if (!sval_is_max(rl_max_sval(right_orig))) {
 741                         left_true = remove_range_sval(left_true, add_one(rl_max_sval(right_orig)), max);
 742                 }
 743                 if (!sval_is_min(rl_min_sval(right_orig))) {
 744                         left_true = remove_range_sval(left_true, min, sub_one(rl_min_sval(right_orig)));
 745                 }
 746                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 747                         left_false = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 748
 749                 if (!sval_is_max(rl_max_sval(left_orig)))
 750                         right_true = remove_range_sval(right_true, add_one(rl_max_sval(left_orig)), max);
 751                 if (!sval_is_min(rl_min_sval(left_orig)))
 752                         right_true = remove_range_sval(right_true, min, sub_one(rl_min_sval(left_orig)));
 753                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 754                         right_false = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 755                 break;
 756         case SPECIAL_UNSIGNED_GTE:
 757         case SPECIAL_GTE:
 758                 if (!sval_is_min(rl_min_sval(right_orig)))
 759                         left_true = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 760                 if (!sval_is_max(rl_max_sval(right_orig)))
 761                         left_false = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 762
 763                 if (!sval_is_max(rl_max_sval(left_orig)))
 764                         right_true = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 765                 if (!sval_is_min(rl_min_sval(left_orig)))
 766                         right_false = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 767                 break;
 768         case '>':
 769         case SPECIAL_UNSIGNED_GT:
 770                 if (!sval_is_min(rl_min_sval(right_orig)))
 771                         left_true = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 772                 if (!sval_is_max(rl_max_sval(right_orig)))
 773                         left_false = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 774
 775                 if (!sval_is_max(rl_max_sval(left_orig)))
 776                         right_true = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 777                 if (!sval_is_min(rl_min_sval(left_orig)))
 778                         right_false = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 779                 break;
 780         case SPECIAL_NOTEQUAL:
 781                 if (!sval_is_max(rl_max_sval(right_orig)))
 782                         left_false = remove_range_sval(left_false, add_one(rl_max_sval(right_orig)), max);
 783                 if (!sval_is_min(rl_min_sval(right_orig)))
 784                         left_false = remove_range_sval(left_false, min, sub_one(rl_min_sval(right_orig)));
 785                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 786                         left_true = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 787
 788                 if (!sval_is_max(rl_max_sval(left_orig)))
 789                         right_false = remove_range_sval(right_false, add_one(rl_max_sval(left_orig)), max);
 790                 if (!sval_is_min(rl_min_sval(left_orig)))
 791                         right_false = remove_range_sval(right_false, min, sub_one(rl_min_sval(left_orig)));
 792                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 793                         right_true = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 794                 break;
 795         default:
 796                 return;
 797         }
 798
 799         left_true_state = alloc_estate_range_list_sval(cast_rl(left_true, get_type(left)));
 800         left_false_state = alloc_estate_range_list_sval(cast_rl(left_false, get_type(left)));
 801         right_true_state = alloc_estate_range_list_sval(cast_rl(right_true, get_type(right)));
 802         right_false_state = alloc_estate_range_list_sval(cast_rl(right_false, get_type(right)));
 803
 804         if (left_postop == SPECIAL_INCREMENT) {
 805                 left_true_state = increment_state(left_true_state);
 806                 left_false_state = increment_state(left_false_state);
 807         }
 808         if (left_postop == SPECIAL_DECREMENT) {
 809                 left_true_state = decrement_state(left_true_state);
 810                 left_false_state = decrement_state(left_false_state);
 811         }
 812         if (right_postop == SPECIAL_INCREMENT) {
 813                 right_true_state = increment_state(right_true_state);
 814                 right_false_state = increment_state(right_false_state);
 815         }
 816         if (right_postop == SPECIAL_DECREMENT) {
 817                 right_true_state = decrement_state(right_true_state);
 818                 right_false_state = decrement_state(right_false_state);
 819         }
 820
 821         set_extra_expr_true_false(left, left_true_state, left_false_state);
 822         set_extra_expr_true_false(right, right_true_state, right_false_state);
 823 }
 824
 825 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 826 void __extra_match_condition(struct expression *expr)
 827 {
 828         struct symbol *sym;
 829         char *name;
 830         struct smatch_state *pre_state;
 831         struct smatch_state *true_state;
 832         struct smatch_state *false_state;
 833
 834         expr = strip_expr(expr);
 835         switch (expr->type) {
 836         case EXPR_CALL:
 837                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 838                 return;
 839         case EXPR_PREOP:
 840         case EXPR_SYMBOL:
 841         case EXPR_DEREF:
 842                 name = get_variable_from_expr(expr, &sym);
 843                 if (!name)
 844                         return;
 845                 pre_state = get_state(my_id, name, sym);
 846                 true_state = add_filter(pre_state, ll_to_sval(0));
 847                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 848                         false_state = alloc_estate_sval(ll_to_sval(0));
 849                 else
 850                         false_state = alloc_estate_empty();
 851                 set_extra_true_false(name, sym, true_state, false_state);
 852                 free_string(name);
 853                 return;
 854         case EXPR_COMPARE:
 855                 match_comparison(expr);
 856                 return;
 857         case EXPR_ASSIGNMENT:
 858                 __extra_match_condition(expr->left);
 859                 return;
 860         }
 861 }
 862
 863 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 864 int implied_not_equal(struct expression *expr, long long val)
 865 {
 866         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 867 }
 868
 869 int get_implied_range_list_sval(struct expression *expr, struct range_list_sval **rl)
 870 {
 871         sval_t sval;
 872         struct smatch_state *state;
 873         sval_t min, max;
 874
 875         *rl = NULL;
 876
 877         expr = strip_parens(expr);
 878         if (!expr)
 879                 return 0;
 880
 881         state = get_state_expr(my_id, expr);
 882         if (state) {
 883                 *rl = clone_range_list_sval(estate_ranges_sval(state));
 884                 goto out;
 885         }
 886
 887         if (expr->type == EXPR_CALL) {
 888                 if (get_implied_return_sval(expr, rl))
 889                         goto out;
 890                 *rl = db_return_vals(expr);
 891                 goto out;
 892         }
 893
 894         if (get_implied_value_sval(expr, &sval)) {
 895                 add_range_sval(rl, sval, sval);
 896                 goto out;
 897         }
 898
 899         if (expr->type == EXPR_BINOP && expr->op == '%') {
 900                 if (!get_implied_value_sval(expr->right, &sval))
 901                         return 0;
 902                 add_range_sval(rl, ll_to_sval(0), ll_to_sval(sval.value - 1));
 903                 goto out;
 904         }
 905
 906         if (!get_implied_min_sval(expr, &min))
 907                 return 0;
 908         if (!get_implied_max_sval(expr, &max))
 909                 return 0;
 910
 911         *rl = alloc_range_list_sval(min, max);
 912
 913 out:
 914         if (is_whole_range_rl_sval(*rl))
 915                 return 0;
 916         return 1;
 917 }
 918
 919 int is_whole_range(struct smatch_state *state)
 920 {
 921         return is_whole_range_rl_sval(estate_ranges_sval(state));
 922 }
 923
 924 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 925 {
 926         if (is_whole_range(state))
 927                 return;
 928         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 929 }
 930
 931 static void match_call_info(struct expression *expr)
 932 {
 933         struct range_list_sval *rl = NULL;
 934         struct expression *arg;
 935         char *name;
 936         int i = 0;
 937
 938         name = get_fnptr_name(expr->fn);
 939         if (!name)
 940                 return;
 941
 942         FOR_EACH_PTR(expr->args, arg) {
 943                 if (get_implied_range_list_sval(arg, &rl) && !is_whole_range_rl_sval(rl)) {
 944                         sm_msg("info: passes param_value '%s' %d '$$' %s %s",
 945                                name, i, show_ranges_sval(rl),
 946                                is_static(expr->fn) ? "static" : "global");
 947                 }
 948                 i++;
 949         } END_FOR_EACH_PTR(arg);
 950
 951         free_string(name);
 952 }
 953
 954 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
 955 {
 956         struct range_list_sval *rl = NULL;
 957         struct smatch_state *state;
 958         char fullname[256];
 959
 960         if (strncmp(key, "$$", 2))
 961                 return;
 962
 963         snprintf(fullname, 256, "%s%s", name, key + 2);
 964         get_value_ranges_sval(value, &rl);
 965         state = alloc_estate_range_list_sval(rl);
 966         set_state(SMATCH_EXTRA, fullname, sym, state);
 967 }
 968
 969 static void match_call_assign(struct expression *expr)
 970 {
 971         if (expr->op != '=')
 972                 return;
 973
 974         /* if we have a db set up this gets set in smatch_function_hooks.c */
 975         if (option_no_db)
 976                 set_extra_expr_mod(expr->left, extra_undefined(get_type(expr->left)));
 977 }
 978
 979 void register_smatch_extra(int id)
 980 {
 981         my_id = id;
 982
 983         alloc_estate_undefined();
 984         add_merge_hook(my_id, &merge_func);
 985         add_unmatched_state_hook(my_id, &unmatched_state);
 986         add_hook(&unop_expr, OP_HOOK);
 987         add_hook(&asm_expr, ASM_HOOK);
 988         add_hook(&match_function_def, FUNC_DEF_HOOK);
 989         add_hook(&match_declarations, DECLARATION_HOOK);
 990         if (option_info) {
 991                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
 992                 add_member_info_callback(my_id, struct_member_callback);
 993         }
 994         add_definition_db_callback(set_param_value, PARAM_VALUE);
 995 }
 996
 997 void register_smatch_extra_late(int id)
 998 {
 999         add_hook(&match_dereferences, DEREF_HOOK);
1000         add_hook(&match_pointer_as_array, OP_HOOK);
1001         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1002         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1003         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1004         add_hook(&match_assign, ASSIGNMENT_HOOK);
1005         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
1006 }