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 int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 399 {
 400         if (!one || !two)
 401                 return 0;
 402         if (one->type == SYM_PTR && two->type == SYM_PTR)
 403                 return 1;
 404         return types_equiv(one, two);
 405 }
 406
 407 static void match_assign(struct expression *expr)
 408 {
 409         struct range_list_sval *rl = NULL;
 410         struct expression *left;
 411         struct expression *right;
 412         struct symbol *right_sym;
 413         char *right_name;
 414         struct symbol *sym;
 415         char *name;
 416         sval_t value;
 417         int known;
 418         sval_t right_min, right_max;
 419         sval_t tmp;
 420
 421         if (__is_condition_assign(expr))
 422                 return;
 423         left = strip_expr(expr->left);
 424         name = get_variable_from_expr(left, &sym);
 425         if (!name)
 426                 return;
 427         right = strip_parens(expr->right);
 428         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 429                 right = strip_parens(right->left);
 430
 431         if (expr->op == '=' && right->type == EXPR_CALL)
 432                 return;  /* these are handled in match_call_assign() */
 433
 434         right_name = get_variable_from_expr(right, &right_sym);
 435         if (expr->op == '=' && right_name && right_sym &&
 436             types_equiv_or_pointer(get_type(expr->left), get_type(expr->right))) {
 437                 set_equiv(left, right);
 438                 goto free;
 439         }
 440
 441         right_min = sval_type_min(get_type(expr->right));
 442         right_max = sval_type_max(get_type(expr->right));
 443
 444         known = get_implied_value_sval(right, &value);
 445         switch (expr->op) {
 446         case '=': {
 447                 if (get_implied_range_list_sval(right, &rl)) {
 448                         rl = cast_rl(rl, get_type(expr->left));
 449                         set_extra_mod(name, sym, alloc_estate_range_list_sval(rl));
 450                         goto free;
 451                 }
 452
 453                 break;
 454         }
 455         case SPECIAL_ADD_ASSIGN:
 456                 if (get_implied_min_sval(left, &tmp)) {
 457                         if (known)
 458                                 right_min = sval_binop(tmp, '+', value);
 459                         else
 460                                 right_min = tmp;
 461                 }
 462                 if (!inside_loop() && known && get_implied_max_sval(left, &tmp))
 463                         right_max = sval_binop(tmp, '+', value);
 464                 break;
 465         case SPECIAL_SUB_ASSIGN:
 466                 if (get_implied_max_sval(left, &tmp)) {
 467                         if (known)
 468                                 right_max = sval_binop(tmp, '-', value);
 469                         else
 470                                 right_max = tmp;
 471                 }
 472                 if (!inside_loop() && known && get_implied_min_sval(left, &tmp))
 473                         right_min = sval_binop(tmp, '-', value);
 474                 break;
 475         }
 476         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 477                 rl = cast_rl(alloc_range_list_sval(right_min, right_max), get_type(expr->left));
 478         else
 479                 rl = whole_range_list_sval(get_type(expr->left));
 480         set_extra_mod(name, sym, alloc_estate_range_list_sval(rl));
 481 free:
 482         free_string(right_name);
 483         free_string(name);
 484 }
 485
 486 static void reset_struct_members(struct sm_state *sm)
 487 {
 488         set_extra_mod(sm->name, sm->sym, extra_undefined(estate_type(sm->state)));
 489 }
 490
 491 static struct smatch_state *increment_state(struct smatch_state *state)
 492 {
 493         sval_t min = estate_min_sval(state);
 494         sval_t max = estate_max_sval(state);
 495
 496         if (inside_loop())
 497                 max = sval_type_max(max.type);
 498
 499         if (!sval_is_min(min))
 500                 min.value++;
 501         if (!sval_is_max(max))
 502                 max.value++;
 503         return alloc_estate_range_sval(min, max);
 504 }
 505
 506 static struct smatch_state *decrement_state(struct smatch_state *state)
 507 {
 508         sval_t min = estate_min_sval(state);
 509         sval_t max = estate_max_sval(state);
 510
 511         if (inside_loop())
 512                 min = sval_type_min(min.type);
 513
 514         if (!sval_is_min(min))
 515                 min.value--;
 516         if (!sval_is_max(max))
 517                 max.value--;
 518         return alloc_estate_range_sval(min, max);
 519 }
 520
 521 static void unop_expr(struct expression *expr)
 522 {
 523         struct smatch_state *state;
 524
 525         if (expr->smatch_flags & Handled)
 526                 return;
 527
 528         switch (expr->op) {
 529         case SPECIAL_INCREMENT:
 530                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 531                 state = increment_state(state);
 532                 set_extra_expr_mod(expr->unop, state);
 533                 break;
 534         case SPECIAL_DECREMENT:
 535                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 536                 state = decrement_state(state);
 537                 set_extra_expr_mod(expr->unop, state);
 538                 break;
 539         default:
 540                 return;
 541         }
 542 }
 543
 544 static void asm_expr(struct statement *stmt)
 545 {
 546
 547         struct expression *expr;
 548         int state = 0;
 549
 550         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 551                 switch (state) {
 552                 case 0: /* identifier */
 553                 case 1: /* constraint */
 554                         state++;
 555                         continue;
 556                 case 2: /* expression */
 557                         state = 0;
 558                         set_extra_expr_mod(expr, extra_undefined(get_type(expr)));
 559                         continue;
 560                 }
 561         } END_FOR_EACH_PTR(expr);
 562 }
 563
 564 static void delete_state_tracker(struct tracker *t)
 565 {
 566         remove_from_equiv(t->name, t->sym);
 567         delete_state(t->owner, t->name, t->sym);
 568 }
 569
 570 static void scoped_state_extra(const char *name, struct symbol *sym)
 571 {
 572         struct tracker *t;
 573
 574         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 575         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 576 }
 577
 578 static void match_declarations(struct symbol *sym)
 579 {
 580         const char *name;
 581
 582         if (sym->ident) {
 583                 name = sym->ident->name;
 584                 if (!sym->initializer) {
 585                         set_state(SMATCH_EXTRA, name, sym, extra_undefined(get_real_base_type(sym)));
 586                         scoped_state_extra(name, sym);
 587                 }
 588         }
 589 }
 590
 591 static void check_dereference(struct expression *expr)
 592 {
 593         set_extra_expr_nomod(expr, alloc_estate_range_sval(valid_ptr_min_sval, valid_ptr_max_sval));
 594 }
 595
 596 static void match_dereferences(struct expression *expr)
 597 {
 598         if (expr->type != EXPR_PREOP)
 599                 return;
 600         check_dereference(expr->unop);
 601 }
 602
 603 static void match_pointer_as_array(struct expression *expr)
 604 {
 605         if (!is_array(expr))
 606                 return;
 607         check_dereference(expr->unop->left);
 608 }
 609
 610 static void set_param_dereferenced(struct expression *arg, char *unused)
 611 {
 612         check_dereference(arg);
 613 }
 614
 615 static void match_function_def(struct symbol *sym)
 616 {
 617         struct symbol *arg;
 618
 619         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 620                 if (!arg->ident)
 621                         continue;
 622                 set_state(my_id, arg->ident->name, arg, extra_undefined(get_real_base_type(arg)));
 623         } END_FOR_EACH_PTR(arg);
 624 }
 625
 626 static int match_func_comparison(struct expression *expr)
 627 {
 628         struct expression *left = strip_expr(expr->left);
 629         struct expression *right = strip_expr(expr->right);
 630         sval_t sval;
 631
 632         if (left->type == EXPR_CALL) {
 633                 if (!get_implied_value_sval(right, &sval))
 634                         return 1;
 635                 function_comparison(expr->op, left, sval, 1);
 636                 return 1;
 637         }
 638
 639         if (right->type == EXPR_CALL) {
 640                 if (!get_implied_value_sval(left, &sval))
 641                         return 1;
 642                 function_comparison(expr->op, right, sval, 0);
 643                 return 1;
 644         }
 645
 646         return 0;
 647 }
 648
 649 static sval_t add_one(sval_t sval)
 650 {
 651         sval.value++;
 652         return sval;
 653 }
 654
 655 static sval_t sub_one(sval_t sval)
 656 {
 657         sval.value--;
 658         return sval;
 659 }
 660
 661 static void match_comparison(struct expression *expr)
 662 {
 663         struct expression *left = strip_expr(expr->left);
 664         struct expression *right = strip_expr(expr->right);
 665         struct symbol *type;
 666         struct range_list_sval *left_orig;
 667         struct range_list_sval *left_true;
 668         struct range_list_sval *left_false;
 669         struct range_list_sval *right_orig;
 670         struct range_list_sval *right_true;
 671         struct range_list_sval *right_false;
 672         struct smatch_state *left_true_state;
 673         struct smatch_state *left_false_state;
 674         struct smatch_state *right_true_state;
 675         struct smatch_state *right_false_state;
 676         sval_t min, max;
 677         int left_postop = 0;
 678         int right_postop = 0;
 679
 680         if (match_func_comparison(expr))
 681                 return;
 682
 683         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 684                 if (left->type == EXPR_POSTOP) {
 685                         left->smatch_flags |= Handled;
 686                         left_postop = left->op;
 687                 }
 688                 left = strip_expr(left->unop);
 689         }
 690
 691         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 692                 if (right->type == EXPR_POSTOP) {
 693                         right->smatch_flags |= Handled;
 694                         right_postop = right->op;
 695                 }
 696                 right = strip_expr(right->unop);
 697         }
 698
 699         type = get_type(expr);
 700         if (!type) {
 701                 sm_msg("debug: failed to get type for '%s'", get_variable_from_expr_complex(expr, NULL));
 702                 type = &llong_ctype;
 703         }
 704
 705         if (get_implied_range_list_sval(left, &left_orig)) {
 706                 left_orig = cast_rl(left_orig, type);
 707         } else {
 708                 min = sval_type_min(get_type(expr->left));
 709                 max = sval_type_max(get_type(expr->left));
 710                 left_orig = cast_rl(alloc_range_list_sval(min, max), type);
 711         }
 712
 713         if (get_implied_range_list_sval(right, &right_orig)) {
 714                 right_orig = cast_rl(right_orig, type);
 715         } else {
 716                 min = sval_type_min(get_type(expr->right));
 717                 max = sval_type_max(get_type(expr->right));
 718                 right_orig = cast_rl(alloc_range_list_sval(min, max), type);
 719         }
 720         min = sval_type_min(type);
 721         max = sval_type_max(type);
 722
 723         left_true = clone_range_list_sval(left_orig);
 724         left_false = clone_range_list_sval(left_orig);
 725         right_true = clone_range_list_sval(right_orig);
 726         right_false = clone_range_list_sval(right_orig);
 727
 728         switch (expr->op) {
 729         case '<':
 730         case SPECIAL_UNSIGNED_LT:
 731                 if (!sval_is_max(rl_max_sval(right_orig))) {
 732                         left_true = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 733                 }
 734                 if (!sval_is_min(rl_min_sval(right_orig))) {
 735                         left_false = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 736                 }
 737
 738                 if (!sval_is_min(rl_min_sval(left_orig)))
 739                         right_true = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 740                 if (!sval_is_max(rl_max_sval(left_orig)))
 741                         right_false = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 742                 break;
 743         case SPECIAL_UNSIGNED_LTE:
 744         case SPECIAL_LTE:
 745                 if (!sval_is_max(rl_max_sval(right_orig)))
 746                         left_true = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 747                 if (!sval_is_min(rl_min_sval(right_orig)))
 748                         left_false = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 749
 750                 if (!sval_is_min(rl_min_sval(left_orig)))
 751                         right_true = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 752                 if (!sval_is_max(rl_max_sval(left_orig)))
 753                         right_false = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 754                 break;
 755         case SPECIAL_EQUAL:
 756                 if (!sval_is_max(rl_max_sval(right_orig))) {
 757                         left_true = remove_range_sval(left_true, add_one(rl_max_sval(right_orig)), max);
 758                 }
 759                 if (!sval_is_min(rl_min_sval(right_orig))) {
 760                         left_true = remove_range_sval(left_true, min, sub_one(rl_min_sval(right_orig)));
 761                 }
 762                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 763                         left_false = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 764
 765                 if (!sval_is_max(rl_max_sval(left_orig)))
 766                         right_true = remove_range_sval(right_true, add_one(rl_max_sval(left_orig)), max);
 767                 if (!sval_is_min(rl_min_sval(left_orig)))
 768                         right_true = remove_range_sval(right_true, min, sub_one(rl_min_sval(left_orig)));
 769                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 770                         right_false = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 771                 break;
 772         case SPECIAL_UNSIGNED_GTE:
 773         case SPECIAL_GTE:
 774                 if (!sval_is_min(rl_min_sval(right_orig)))
 775                         left_true = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 776                 if (!sval_is_max(rl_max_sval(right_orig)))
 777                         left_false = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 778
 779                 if (!sval_is_max(rl_max_sval(left_orig)))
 780                         right_true = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 781                 if (!sval_is_min(rl_min_sval(left_orig)))
 782                         right_false = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 783                 break;
 784         case '>':
 785         case SPECIAL_UNSIGNED_GT:
 786                 if (!sval_is_min(rl_min_sval(right_orig)))
 787                         left_true = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 788                 if (!sval_is_max(rl_max_sval(right_orig)))
 789                         left_false = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 790
 791                 if (!sval_is_max(rl_max_sval(left_orig)))
 792                         right_true = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 793                 if (!sval_is_min(rl_min_sval(left_orig)))
 794                         right_false = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 795                 break;
 796         case SPECIAL_NOTEQUAL:
 797                 if (!sval_is_max(rl_max_sval(right_orig)))
 798                         left_false = remove_range_sval(left_false, add_one(rl_max_sval(right_orig)), max);
 799                 if (!sval_is_min(rl_min_sval(right_orig)))
 800                         left_false = remove_range_sval(left_false, min, sub_one(rl_min_sval(right_orig)));
 801                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 802                         left_true = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 803
 804                 if (!sval_is_max(rl_max_sval(left_orig)))
 805                         right_false = remove_range_sval(right_false, add_one(rl_max_sval(left_orig)), max);
 806                 if (!sval_is_min(rl_min_sval(left_orig)))
 807                         right_false = remove_range_sval(right_false, min, sub_one(rl_min_sval(left_orig)));
 808                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 809                         right_true = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 810                 break;
 811         default:
 812                 return;
 813         }
 814
 815         left_true_state = alloc_estate_range_list_sval(cast_rl(left_true, get_type(left)));
 816         left_false_state = alloc_estate_range_list_sval(cast_rl(left_false, get_type(left)));
 817         right_true_state = alloc_estate_range_list_sval(cast_rl(right_true, get_type(right)));
 818         right_false_state = alloc_estate_range_list_sval(cast_rl(right_false, get_type(right)));
 819
 820         if (left_postop == SPECIAL_INCREMENT) {
 821                 left_true_state = increment_state(left_true_state);
 822                 left_false_state = increment_state(left_false_state);
 823         }
 824         if (left_postop == SPECIAL_DECREMENT) {
 825                 left_true_state = decrement_state(left_true_state);
 826                 left_false_state = decrement_state(left_false_state);
 827         }
 828         if (right_postop == SPECIAL_INCREMENT) {
 829                 right_true_state = increment_state(right_true_state);
 830                 right_false_state = increment_state(right_false_state);
 831         }
 832         if (right_postop == SPECIAL_DECREMENT) {
 833                 right_true_state = decrement_state(right_true_state);
 834                 right_false_state = decrement_state(right_false_state);
 835         }
 836
 837         set_extra_expr_true_false(left, left_true_state, left_false_state);
 838         set_extra_expr_true_false(right, right_true_state, right_false_state);
 839 }
 840
 841 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 842 void __extra_match_condition(struct expression *expr)
 843 {
 844         struct symbol *sym;
 845         char *name;
 846         struct smatch_state *pre_state;
 847         struct smatch_state *true_state;
 848         struct smatch_state *false_state;
 849
 850         expr = strip_expr(expr);
 851         switch (expr->type) {
 852         case EXPR_CALL:
 853                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 854                 return;
 855         case EXPR_PREOP:
 856         case EXPR_SYMBOL:
 857         case EXPR_DEREF: {
 858                 sval_t zero;
 859
 860                 zero = sval_blank(expr);
 861                 zero.value = 0;
 862
 863                 name = get_variable_from_expr(expr, &sym);
 864                 if (!name)
 865                         return;
 866                 pre_state = get_state(my_id, name, sym);
 867                 true_state = add_filter(pre_state, zero);
 868                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 869                         false_state = alloc_estate_sval(zero);
 870                 else
 871                         false_state = alloc_estate_empty();
 872                 set_extra_true_false(name, sym, true_state, false_state);
 873                 free_string(name);
 874                 return;
 875         }
 876         case EXPR_COMPARE:
 877                 match_comparison(expr);
 878                 return;
 879         case EXPR_ASSIGNMENT:
 880                 __extra_match_condition(expr->left);
 881                 return;
 882         }
 883 }
 884
 885 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 886 int implied_not_equal(struct expression *expr, long long val)
 887 {
 888         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 889 }
 890
 891 int get_implied_range_list_sval(struct expression *expr, struct range_list_sval **rl)
 892 {
 893         sval_t sval;
 894         struct smatch_state *state;
 895         sval_t min, max;
 896
 897         *rl = NULL;
 898
 899         expr = strip_parens(expr);
 900         if (!expr)
 901                 return 0;
 902
 903         state = get_state_expr(my_id, expr);
 904         if (state) {
 905                 *rl = clone_range_list_sval(estate_ranges_sval(state));
 906                 goto out;
 907         }
 908
 909         if (expr->type == EXPR_CALL) {
 910                 if (get_implied_return_sval(expr, rl))
 911                         goto out;
 912                 *rl = db_return_vals(expr);
 913                 goto out;
 914         }
 915
 916         if (get_implied_value_sval(expr, &sval)) {
 917                 add_range_sval(rl, sval, sval);
 918                 goto out;
 919         }
 920
 921         if (expr->type == EXPR_BINOP && expr->op == '%') {
 922                 if (!get_implied_value_sval(expr->right, &sval))
 923                         return 0;
 924                 add_range_sval(rl, ll_to_sval(0), ll_to_sval(sval.value - 1));
 925                 goto out;
 926         }
 927
 928         if (!get_implied_min_sval(expr, &min))
 929                 return 0;
 930         if (!get_implied_max_sval(expr, &max))
 931                 return 0;
 932
 933         *rl = alloc_range_list_sval(min, max);
 934
 935 out:
 936         if (is_whole_range_rl_sval(*rl))
 937                 return 0;
 938         return 1;
 939 }
 940
 941 int is_whole_range(struct smatch_state *state)
 942 {
 943         return is_whole_range_rl_sval(estate_ranges_sval(state));
 944 }
 945
 946 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 947 {
 948         if (is_whole_range(state))
 949                 return;
 950         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 951 }
 952
 953 static void match_call_info(struct expression *expr)
 954 {
 955         struct range_list_sval *rl = NULL;
 956         struct expression *arg;
 957         char *name;
 958         int i = 0;
 959
 960         name = get_fnptr_name(expr->fn);
 961         if (!name)
 962                 return;
 963
 964         FOR_EACH_PTR(expr->args, arg) {
 965                 if (get_implied_range_list_sval(arg, &rl) && !is_whole_range_rl_sval(rl)) {
 966                         sm_msg("info: passes param_value '%s' %d '$$' %s %s",
 967                                name, i, show_ranges_sval(rl),
 968                                is_static(expr->fn) ? "static" : "global");
 969                 }
 970                 i++;
 971         } END_FOR_EACH_PTR(arg);
 972
 973         free_string(name);
 974 }
 975
 976 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
 977 {
 978         struct range_list_sval *rl = NULL;
 979         struct smatch_state *state;
 980         char fullname[256];
 981
 982         if (strncmp(key, "$$", 2))
 983                 return;
 984
 985         snprintf(fullname, 256, "%s%s", name, key + 2);
 986         get_value_ranges_sval(value, &rl);
 987         rl = cast_rl(rl, get_real_base_type(sym));
 988         state = alloc_estate_range_list_sval(rl);
 989         set_state(SMATCH_EXTRA, fullname, sym, state);
 990 }
 991
 992 static void match_call_assign(struct expression *expr)
 993 {
 994         if (expr->op != '=')
 995                 return;
 996
 997         /* if we have a db set up this gets set in smatch_function_hooks.c */
 998         if (option_no_db)
 999                 set_extra_expr_mod(expr->left, extra_undefined(get_type(expr->left)));
1000 }
1001
1002 void register_smatch_extra(int id)
1003 {
1004         my_id = id;
1005
1006         add_merge_hook(my_id, &merge_func);
1007         add_unmatched_state_hook(my_id, &unmatched_state);
1008         add_hook(&unop_expr, OP_HOOK);
1009         add_hook(&asm_expr, ASM_HOOK);
1010         add_hook(&match_function_def, FUNC_DEF_HOOK);
1011         add_hook(&match_declarations, DECLARATION_HOOK);
1012         if (option_info) {
1013                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1014                 add_member_info_callback(my_id, struct_member_callback);
1015         }
1016         add_definition_db_callback(set_param_value, PARAM_VALUE);
1017 }
1018
1019 void register_smatch_extra_late(int id)
1020 {
1021         add_hook(&match_dereferences, DEREF_HOOK);
1022         add_hook(&match_pointer_as_array, OP_HOOK);
1023         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1024         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1025         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1026         add_hook(&match_assign, ASSIGNMENT_HOOK);
1027         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
1028 }