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 *rl;
 134
 135         if (!orig)
 136                 orig = extra_undefined(filter_min.type);
 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, 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 *value_ranges;
 151         struct related_list *rlist;
 152
 153         if (estates_equiv(s1, s2))
 154                 return s1;
 155
 156         value_ranges = range_list_union(estate_ranges(s1), estate_ranges(s2));
 157         tmp = alloc_estate_range_list(value_ranges);
 158         rlist = get_shared_relations(estate_related(s1), estate_related(s2));
 159         set_related(tmp, rlist);
 160         if (estate_has_hard_max(s1) && estate_has_hard_max(s2))
 161                 estate_set_hard_max(tmp);
 162
 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         struct smatch_state *estate;
 172         sval_t start;
 173
 174         condition = strip_expr(loop->iterator_pre_condition);
 175         if (!condition)
 176                 return NULL;
 177         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 178                 return NULL;
 179         if (condition->op != SPECIAL_DECREMENT)
 180                 return NULL;
 181
 182         iter_var = condition->unop;
 183         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 184         if (!sm)
 185                 return NULL;
 186         if (sval_cmp_val(estate_min(sm->state), 0) < 0)
 187                 return NULL;
 188         start = estate_max(sm->state);
 189         if  (sval_cmp_val(start, 0) <= 0)
 190                 return NULL;
 191         if (!sval_is_max(start))
 192                 start.value--;
 193
 194         if (condition->type == EXPR_PREOP) {
 195                 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
 196                 if (!sval_is_max(start))
 197                         estate_set_hard_max(estate);
 198                 set_extra_expr_mod(iter_var, estate);
 199         }
 200         if (condition->type == EXPR_POSTOP) {
 201                 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
 202                 if (!sval_is_max(start))
 203                         estate_set_hard_max(estate);
 204                 set_extra_expr_mod(iter_var, estate);
 205         }
 206         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 207 }
 208
 209 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 210                                                 struct expression *condition)
 211 {
 212         struct expression *iter_var;
 213         struct sm_state *sm;
 214         struct smatch_state *estate;
 215         sval_t start, end;
 216
 217         iter_var = iter_expr->unop;
 218         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 219         if (!sm)
 220                 return NULL;
 221         if (!estate_get_single_value(sm->state, &start))
 222                 return NULL;
 223         if (!get_implied_value(condition->right, &end))
 224                 end = sval_type_max(get_type(iter_var));
 225
 226         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 227                 return NULL;
 228
 229         switch (condition->op) {
 230         case SPECIAL_NOTEQUAL:
 231         case '<':
 232                 if (!sval_is_max(end))
 233                         end.value--;
 234                 break;
 235         case SPECIAL_LTE:
 236                 break;
 237         default:
 238                 return NULL;
 239         }
 240         if (sval_cmp(end, start) < 0)
 241                 return NULL;
 242         estate = alloc_estate_range(start, end);
 243         if (!sval_is_max(end))
 244                 estate_set_hard_max(estate);
 245         set_extra_expr_mod(iter_var, estate);
 246         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 247 }
 248
 249 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 250                                                 struct expression *condition)
 251 {
 252         struct expression *iter_var;
 253         struct sm_state *sm;
 254         struct smatch_state *estate;
 255         sval_t start, end;
 256
 257         iter_var = iter_expr->unop;
 258         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 259         if (!sm)
 260                 return NULL;
 261         if (!estate_get_single_value(sm->state, &start))
 262                 return NULL;
 263         if (!get_implied_value(condition->right, &end))
 264                 end = sval_type_min(get_type(iter_var));
 265         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 266                 return NULL;
 267
 268         switch (condition->op) {
 269         case SPECIAL_NOTEQUAL:
 270         case '>':
 271                 if (!sval_is_min(end) && !sval_is_max(end))
 272                         end.value++;
 273                 break;
 274         case SPECIAL_GTE:
 275                 break;
 276         default:
 277                 return NULL;
 278         }
 279         if (sval_cmp(end, start) > 0)
 280                 return NULL;
 281         estate = alloc_estate_range(end, start);
 282         estate_set_hard_max(estate);
 283         set_extra_expr_mod(iter_var, estate);
 284         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 285 }
 286
 287 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 288 {
 289         struct expression *iter_expr;
 290         struct expression *condition;
 291
 292         if (!loop->iterator_post_statement)
 293                 return NULL;
 294         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 295                 return NULL;
 296         iter_expr = loop->iterator_post_statement->expression;
 297         if (!loop->iterator_pre_condition)
 298                 return NULL;
 299         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 300                 return NULL;
 301         condition = loop->iterator_pre_condition;
 302
 303         if (iter_expr->op == SPECIAL_INCREMENT)
 304                 return handle_canonical_for_inc(iter_expr, condition);
 305         if (iter_expr->op == SPECIAL_DECREMENT)
 306                 return handle_canonical_for_dec(iter_expr, condition);
 307         return NULL;
 308 }
 309
 310 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 311 {
 312         struct sm_state *ret;
 313
 314         __push_fake_cur_slist();
 315         if (!loop->iterator_post_statement)
 316                 ret = handle_canonical_while_count_down(loop);
 317         else
 318                 ret = handle_canonical_for_loops(loop);
 319         *slist = __pop_fake_cur_slist();
 320         return ret;
 321 }
 322
 323 int __iterator_unchanged(struct sm_state *sm)
 324 {
 325         if (!sm)
 326                 return 0;
 327         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 328                 return 1;
 329         return 0;
 330 }
 331
 332 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 333 {
 334         sval_t after_value;
 335
 336         /* paranoid checking.  prolly not needed */
 337         condition = strip_expr(condition);
 338         if (!condition)
 339                 return;
 340         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 341                 return;
 342         if (condition->op != SPECIAL_DECREMENT)
 343                 return;
 344         after_value = estate_min(sm->state);
 345         after_value.value--;
 346         set_extra_mod(sm->name, sm->sym, alloc_estate(after_value));
 347 }
 348
 349 void __extra_pre_loop_hook_after(struct sm_state *sm,
 350                                 struct statement *iterator,
 351                                 struct expression *condition)
 352 {
 353         struct expression *iter_expr;
 354         char *name;
 355         struct symbol *sym;
 356         sval_t value;
 357         int left = 0;
 358         struct smatch_state *state;
 359         sval_t min, max;
 360
 361         if (!iterator) {
 362                 while_count_down_after(sm, condition);
 363                 return;
 364         }
 365
 366         iter_expr = iterator->expression;
 367
 368         if (condition->type != EXPR_COMPARE)
 369                 return;
 370         if (!get_value(condition->left, &value)) {
 371                 if (!get_value(condition->right, &value))
 372                         return;
 373                 left = 1;
 374         }
 375         if (left)
 376                 name = get_variable_from_expr(condition->left, &sym);
 377         else
 378                 name = get_variable_from_expr(condition->right, &sym);
 379         if (!name || !sym)
 380                 goto free;
 381         if (sym != sm->sym || strcmp(name, sm->name))
 382                 goto free;
 383         state = get_state(my_id, name, sym);
 384         min = estate_min(state);
 385         max = estate_max(state);
 386         if (iter_expr->op == SPECIAL_INCREMENT &&
 387             !sval_is_min(min) && sval_is_max(max))
 388                 set_extra_mod(name, sym, alloc_estate(min));
 389         else if (sval_is_min(min) && !sval_is_max(max))
 390                 set_extra_mod(name, sym, alloc_estate(max));
 391
 392 free:
 393         free_string(name);
 394         return;
 395 }
 396
 397 static struct smatch_state *unmatched_state(struct sm_state *sm)
 398 {
 399         return extra_undefined(estate_type(sm->state));
 400 }
 401
 402 static void match_function_call(struct expression *expr)
 403 {
 404         struct expression *arg;
 405         struct expression *tmp;
 406
 407         FOR_EACH_PTR(expr->args, arg) {
 408                 tmp = strip_expr(arg);
 409                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 410                         remove_from_equiv_expr(tmp->unop);
 411                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined(get_type(tmp->unop)));
 412                 }
 413         } END_FOR_EACH_PTR(arg);
 414 }
 415
 416 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 417 {
 418         if (!one || !two)
 419                 return 0;
 420         if (one->type == SYM_PTR && two->type == SYM_PTR)
 421                 return 1;
 422         return types_equiv(one, two);
 423 }
 424
 425 static void match_assign(struct expression *expr)
 426 {
 427         struct range_list *rl = NULL;
 428         struct expression *left;
 429         struct expression *right;
 430         struct symbol *right_sym;
 431         char *right_name;
 432         struct symbol *sym;
 433         char *name;
 434         sval_t value;
 435         int known;
 436         sval_t right_min, right_max;
 437         sval_t tmp;
 438
 439         if (__is_condition_assign(expr))
 440                 return;
 441         left = strip_expr(expr->left);
 442         name = get_variable_from_expr(left, &sym);
 443         if (!name)
 444                 return;
 445         right = strip_parens(expr->right);
 446         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 447                 right = strip_parens(right->left);
 448
 449         if (expr->op == '=' && right->type == EXPR_CALL)
 450                 return;  /* these are handled in match_call_assign() */
 451
 452         right_name = get_variable_from_expr(right, &right_sym);
 453         if (expr->op == '=' && right_name && right_sym &&
 454             types_equiv_or_pointer(get_type(expr->left), get_type(expr->right))) {
 455                 set_equiv(left, right);
 456                 goto free;
 457         }
 458
 459         right_min = sval_type_min(get_type(expr->right));
 460         right_max = sval_type_max(get_type(expr->right));
 461
 462         known = get_implied_value(right, &value);
 463         switch (expr->op) {
 464         case '=': {
 465                 if (get_implied_range_list(right, &rl)) {
 466                         rl = cast_rl(get_type(expr->left), rl);
 467                         set_extra_mod(name, sym, alloc_estate_range_list(rl));
 468                         goto free;
 469                 }
 470
 471                 break;
 472         }
 473         case SPECIAL_ADD_ASSIGN:
 474                 if (get_implied_min(left, &tmp)) {
 475                         if (known)
 476                                 right_min = sval_binop(tmp, '+', value);
 477                         else
 478                                 right_min = tmp;
 479                 }
 480                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 481                         right_max = sval_binop(tmp, '+', value);
 482                 break;
 483         case SPECIAL_SUB_ASSIGN:
 484                 if (get_implied_max(left, &tmp)) {
 485                         if (known)
 486                                 right_max = sval_binop(tmp, '-', value);
 487                         else
 488                                 right_max = tmp;
 489                 }
 490                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 491                         right_min = sval_binop(tmp, '-', value);
 492                 break;
 493         }
 494         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 495                 rl = cast_rl(get_type(expr->left), alloc_range_list(right_min, right_max));
 496         else
 497                 rl = whole_range_list(get_type(expr->left));
 498         set_extra_mod(name, sym, alloc_estate_range_list(rl));
 499 free:
 500         free_string(right_name);
 501         free_string(name);
 502 }
 503
 504 static void reset_struct_members(struct sm_state *sm)
 505 {
 506         set_extra_mod(sm->name, sm->sym, extra_undefined(estate_type(sm->state)));
 507 }
 508
 509 static struct smatch_state *increment_state(struct smatch_state *state)
 510 {
 511         sval_t min = estate_min(state);
 512         sval_t max = estate_max(state);
 513
 514         if (inside_loop())
 515                 max = sval_type_max(max.type);
 516
 517         if (!sval_is_min(min) && !sval_is_max(min))
 518                 min.value++;
 519         if (!sval_is_min(max) && !sval_is_max(max))
 520                 max.value++;
 521         return alloc_estate_range(min, max);
 522 }
 523
 524 static struct smatch_state *decrement_state(struct smatch_state *state)
 525 {
 526         sval_t min = estate_min(state);
 527         sval_t max = estate_max(state);
 528
 529         if (inside_loop())
 530                 min = sval_type_min(min.type);
 531
 532         if (!sval_is_min(min) && !sval_is_max(min))
 533                 min.value--;
 534         if (!sval_is_min(max) && !sval_is_max(max))
 535                 max.value--;
 536         return alloc_estate_range(min, max);
 537 }
 538
 539 static void unop_expr(struct expression *expr)
 540 {
 541         struct smatch_state *state;
 542
 543         if (expr->smatch_flags & Handled)
 544                 return;
 545
 546         switch (expr->op) {
 547         case SPECIAL_INCREMENT:
 548                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 549                 state = increment_state(state);
 550                 set_extra_expr_mod(expr->unop, state);
 551                 break;
 552         case SPECIAL_DECREMENT:
 553                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 554                 state = decrement_state(state);
 555                 set_extra_expr_mod(expr->unop, state);
 556                 break;
 557         default:
 558                 return;
 559         }
 560 }
 561
 562 static void asm_expr(struct statement *stmt)
 563 {
 564
 565         struct expression *expr;
 566         int state = 0;
 567
 568         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 569                 switch (state) {
 570                 case 0: /* identifier */
 571                 case 1: /* constraint */
 572                         state++;
 573                         continue;
 574                 case 2: /* expression */
 575                         state = 0;
 576                         set_extra_expr_mod(expr, extra_undefined(get_type(expr)));
 577                         continue;
 578                 }
 579         } END_FOR_EACH_PTR(expr);
 580 }
 581
 582 static void delete_state_tracker(struct tracker *t)
 583 {
 584         remove_from_equiv(t->name, t->sym);
 585         delete_state(t->owner, t->name, t->sym);
 586 }
 587
 588 static void scoped_state_extra(const char *name, struct symbol *sym)
 589 {
 590         struct tracker *t;
 591
 592         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 593         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 594 }
 595
 596 static void match_declarations(struct symbol *sym)
 597 {
 598         const char *name;
 599
 600         if (sym->ident) {
 601                 name = sym->ident->name;
 602                 if (!sym->initializer) {
 603                         set_state(SMATCH_EXTRA, name, sym, extra_undefined(get_real_base_type(sym)));
 604                         scoped_state_extra(name, sym);
 605                 }
 606         }
 607 }
 608
 609 static void check_dereference(struct expression *expr)
 610 {
 611         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 612 }
 613
 614 static void match_dereferences(struct expression *expr)
 615 {
 616         if (expr->type != EXPR_PREOP)
 617                 return;
 618         check_dereference(expr->unop);
 619 }
 620
 621 static void match_pointer_as_array(struct expression *expr)
 622 {
 623         if (!is_array(expr))
 624                 return;
 625         check_dereference(expr->unop->left);
 626 }
 627
 628 static void set_param_dereferenced(struct expression *arg, char *unused)
 629 {
 630         check_dereference(arg);
 631 }
 632
 633 static void match_function_def(struct symbol *sym)
 634 {
 635         struct symbol *arg;
 636
 637         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 638                 if (!arg->ident)
 639                         continue;
 640                 set_state(my_id, arg->ident->name, arg, extra_undefined(get_real_base_type(arg)));
 641         } END_FOR_EACH_PTR(arg);
 642 }
 643
 644 static int match_func_comparison(struct expression *expr)
 645 {
 646         struct expression *left = strip_expr(expr->left);
 647         struct expression *right = strip_expr(expr->right);
 648         sval_t sval;
 649
 650         if (left->type == EXPR_CALL) {
 651                 if (!get_implied_value(right, &sval))
 652                         return 1;
 653                 function_comparison(expr->op, left, sval, 1);
 654                 return 1;
 655         }
 656
 657         if (right->type == EXPR_CALL) {
 658                 if (!get_implied_value(left, &sval))
 659                         return 1;
 660                 function_comparison(expr->op, right, sval, 0);
 661                 return 1;
 662         }
 663
 664         return 0;
 665 }
 666
 667 static sval_t add_one(sval_t sval)
 668 {
 669         sval.value++;
 670         return sval;
 671 }
 672
 673 static sval_t sub_one(sval_t sval)
 674 {
 675         sval.value--;
 676         return sval;
 677 }
 678
 679 static void match_comparison(struct expression *expr)
 680 {
 681         struct expression *left = strip_expr(expr->left);
 682         struct expression *right = strip_expr(expr->right);
 683         struct symbol *type;
 684         struct range_list *left_orig;
 685         struct range_list *left_true;
 686         struct range_list *left_false;
 687         struct range_list *right_orig;
 688         struct range_list *right_true;
 689         struct range_list *right_false;
 690         struct smatch_state *left_true_state;
 691         struct smatch_state *left_false_state;
 692         struct smatch_state *right_true_state;
 693         struct smatch_state *right_false_state;
 694         sval_t min, max, dummy;
 695         int left_postop = 0;
 696         int right_postop = 0;
 697
 698         if (match_func_comparison(expr))
 699                 return;
 700
 701         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 702                 if (left->type == EXPR_POSTOP) {
 703                         left->smatch_flags |= Handled;
 704                         left_postop = left->op;
 705                 }
 706                 left = strip_expr(left->unop);
 707         }
 708         while (left->type == EXPR_ASSIGNMENT)
 709                 left = strip_expr(left->left);
 710
 711         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 712                 if (right->type == EXPR_POSTOP) {
 713                         right->smatch_flags |= Handled;
 714                         right_postop = right->op;
 715                 }
 716                 right = strip_expr(right->unop);
 717         }
 718
 719         type = get_type(expr);
 720         if (!type) {
 721                 sm_msg("debug: failed to get type for '%s'", get_variable_from_expr_complex(expr, NULL));
 722                 type = &llong_ctype;
 723         }
 724
 725         if (get_implied_range_list(left, &left_orig)) {
 726                 left_orig = cast_rl(type, left_orig);
 727         } else {
 728                 min = sval_type_min(get_type(left));
 729                 max = sval_type_max(get_type(left));
 730                 left_orig = cast_rl(type, alloc_range_list(min, max));
 731         }
 732
 733         if (get_implied_range_list(right, &right_orig)) {
 734                 right_orig = cast_rl(type, right_orig);
 735         } else {
 736                 min = sval_type_min(get_type(right));
 737                 max = sval_type_max(get_type(right));
 738                 right_orig = cast_rl(type, alloc_range_list(min, max));
 739         }
 740         min = sval_type_min(type);
 741         max = sval_type_max(type);
 742
 743         left_true = clone_range_list(left_orig);
 744         left_false = clone_range_list(left_orig);
 745         right_true = clone_range_list(right_orig);
 746         right_false = clone_range_list(right_orig);
 747
 748         switch (expr->op) {
 749         case '<':
 750         case SPECIAL_UNSIGNED_LT:
 751                 if (!sval_is_max(rl_max(right_orig))) {
 752                         left_true = remove_range(left_orig, rl_max(right_orig), max);
 753                 }
 754                 if (!sval_is_min(rl_min(right_orig))) {
 755                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 756                 }
 757
 758                 if (!sval_is_min(rl_min(left_orig)))
 759                         right_true = remove_range(right_orig, min, rl_min(left_orig));
 760                 if (!sval_is_max(rl_max(left_orig)))
 761                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 762                 break;
 763         case SPECIAL_UNSIGNED_LTE:
 764         case SPECIAL_LTE:
 765                 if (!sval_is_max(rl_max(right_orig)))
 766                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 767                 if (!sval_is_min(rl_min(right_orig)))
 768                         left_false = remove_range(left_orig, min, rl_min(right_orig));
 769
 770                 if (!sval_is_min(rl_min(left_orig)))
 771                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 772                 if (!sval_is_max(rl_max(left_orig)))
 773                         right_false = remove_range(right_orig, rl_max(left_orig), max);
 774                 break;
 775         case SPECIAL_EQUAL:
 776                 if (!sval_is_max(rl_max(right_orig))) {
 777                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 778                 }
 779                 if (!sval_is_min(rl_min(right_orig))) {
 780                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 781                 }
 782                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 783                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 784
 785                 if (!sval_is_max(rl_max(left_orig)))
 786                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 787                 if (!sval_is_min(rl_min(left_orig)))
 788                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 789                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 790                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 791                 break;
 792         case SPECIAL_UNSIGNED_GTE:
 793         case SPECIAL_GTE:
 794                 if (!sval_is_min(rl_min(right_orig)))
 795                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 796                 if (!sval_is_max(rl_max(right_orig)))
 797                         left_false = remove_range(left_orig, rl_max(right_orig), max);
 798
 799                 if (!sval_is_max(rl_max(left_orig)))
 800                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 801                 if (!sval_is_min(rl_min(left_orig)))
 802                         right_false = remove_range(right_orig, min, rl_min(left_orig));
 803                 break;
 804         case '>':
 805         case SPECIAL_UNSIGNED_GT:
 806                 if (!sval_is_min(rl_min(right_orig)))
 807                         left_true = remove_range(left_orig, min, rl_min(right_orig));
 808                 if (!sval_is_max(rl_max(right_orig)))
 809                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 810
 811                 if (!sval_is_max(rl_max(left_orig)))
 812                         right_true = remove_range(right_orig, rl_max(left_orig), max);
 813                 if (!sval_is_min(rl_min(left_orig)))
 814                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 815                 break;
 816         case SPECIAL_NOTEQUAL:
 817                 if (!sval_is_max(rl_max(right_orig)))
 818                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 819                 if (!sval_is_min(rl_min(right_orig)))
 820                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 821                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 822                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 823
 824                 if (!sval_is_max(rl_max(left_orig)))
 825                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 826                 if (!sval_is_min(rl_min(left_orig)))
 827                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 828                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 829                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 830                 break;
 831         default:
 832                 return;
 833         }
 834
 835         left_true_state = alloc_estate_range_list(cast_rl(get_type(left), left_true));
 836         left_false_state = alloc_estate_range_list(cast_rl(get_type(left), left_false));
 837         right_true_state = alloc_estate_range_list(cast_rl(get_type(right), right_true));
 838         right_false_state = alloc_estate_range_list(cast_rl(get_type(right), right_false));
 839
 840         switch (expr->op) {
 841         case '<':
 842         case SPECIAL_UNSIGNED_LT:
 843         case SPECIAL_UNSIGNED_LTE:
 844         case SPECIAL_LTE:
 845                 if (get_hard_max(right, &dummy))
 846                         estate_set_hard_max(left_true_state);
 847                 if (get_hard_max(left, &dummy))
 848                         estate_set_hard_max(right_false_state);
 849                 break;
 850         case '>':
 851         case SPECIAL_UNSIGNED_GT:
 852         case SPECIAL_UNSIGNED_GTE:
 853         case SPECIAL_GTE:
 854                 if (get_hard_max(left, &dummy))
 855                         estate_set_hard_max(right_true_state);
 856                 if (get_hard_max(right, &dummy))
 857                         estate_set_hard_max(left_false_state);
 858                 break;
 859         }
 860
 861         if (get_hard_max(left, &dummy)) {
 862                 estate_set_hard_max(left_true_state);
 863                 estate_set_hard_max(left_false_state);
 864         }
 865         if (get_hard_max(right, &dummy)) {
 866                 estate_set_hard_max(right_true_state);
 867                 estate_set_hard_max(right_false_state);
 868         }
 869
 870         if (left_postop == SPECIAL_INCREMENT) {
 871                 left_true_state = increment_state(left_true_state);
 872                 left_false_state = increment_state(left_false_state);
 873         }
 874         if (left_postop == SPECIAL_DECREMENT) {
 875                 left_true_state = decrement_state(left_true_state);
 876                 left_false_state = decrement_state(left_false_state);
 877         }
 878         if (right_postop == SPECIAL_INCREMENT) {
 879                 right_true_state = increment_state(right_true_state);
 880                 right_false_state = increment_state(right_false_state);
 881         }
 882         if (right_postop == SPECIAL_DECREMENT) {
 883                 right_true_state = decrement_state(right_true_state);
 884                 right_false_state = decrement_state(right_false_state);
 885         }
 886
 887         set_extra_expr_true_false(left, left_true_state, left_false_state);
 888         set_extra_expr_true_false(right, right_true_state, right_false_state);
 889 }
 890
 891 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 892 void __extra_match_condition(struct expression *expr)
 893 {
 894         struct symbol *sym;
 895         char *name;
 896         struct smatch_state *pre_state;
 897         struct smatch_state *true_state;
 898         struct smatch_state *false_state;
 899
 900         expr = strip_expr(expr);
 901         switch (expr->type) {
 902         case EXPR_CALL:
 903                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 904                 return;
 905         case EXPR_PREOP:
 906         case EXPR_SYMBOL:
 907         case EXPR_DEREF: {
 908                 sval_t zero;
 909
 910                 zero = sval_blank(expr);
 911                 zero.value = 0;
 912
 913                 name = get_variable_from_expr(expr, &sym);
 914                 if (!name)
 915                         return;
 916                 pre_state = get_state(my_id, name, sym);
 917                 true_state = add_filter(pre_state, zero);
 918                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 919                         false_state = alloc_estate(zero);
 920                 else
 921                         false_state = alloc_estate_empty();
 922                 set_extra_true_false(name, sym, true_state, false_state);
 923                 free_string(name);
 924                 return;
 925         }
 926         case EXPR_COMPARE:
 927                 match_comparison(expr);
 928                 return;
 929         case EXPR_ASSIGNMENT:
 930                 __extra_match_condition(expr->left);
 931                 return;
 932         }
 933 }
 934
 935 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 936 int implied_not_equal(struct expression *expr, long long val)
 937 {
 938         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 939 }
 940
 941 int get_implied_range_list(struct expression *expr, struct range_list **rl)
 942 {
 943         sval_t sval;
 944         struct smatch_state *state;
 945         sval_t min, max;
 946
 947         *rl = NULL;
 948
 949         expr = strip_parens(expr);
 950         if (!expr)
 951                 return 0;
 952
 953         state = get_state_expr(my_id, expr);
 954         if (state) {
 955                 *rl = clone_range_list(estate_ranges(state));
 956                 goto out;
 957         }
 958
 959         if (expr->type == EXPR_CALL) {
 960                 if (get_implied_return(expr, rl))
 961                         goto out;
 962                 *rl = db_return_vals(expr);
 963                 goto out;
 964         }
 965
 966         if (get_implied_value(expr, &sval)) {
 967                 add_range(rl, sval, sval);
 968                 goto out;
 969         }
 970
 971         if (expr->type == EXPR_BINOP && expr->op == '%') {
 972                 if (!get_implied_value(expr->right, &sval))
 973                         return 0;
 974                 add_range(rl, ll_to_sval(0), ll_to_sval(sval.value - 1));
 975                 goto out;
 976         }
 977
 978         if (!get_implied_min(expr, &min))
 979                 return 0;
 980         if (!get_implied_max(expr, &max))
 981                 return 0;
 982
 983         *rl = alloc_range_list(min, max);
 984
 985 out:
 986         if (is_whole_range_rl(*rl))
 987                 return 0;
 988         return 1;
 989 }
 990
 991 int is_whole_range(struct smatch_state *state)
 992 {
 993         return is_whole_range_rl(estate_ranges(state));
 994 }
 995
 996 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 997 {
 998         if (is_whole_range(state))
 999                 return;
1000         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
1001 }
1002
1003 static void match_call_info(struct expression *expr)
1004 {
1005         struct range_list *rl = NULL;
1006         struct expression *arg;
1007         char *name;
1008         int i = 0;
1009
1010         name = get_fnptr_name(expr->fn);
1011         if (!name)
1012                 return;
1013
1014         FOR_EACH_PTR(expr->args, arg) {
1015                 if (get_implied_range_list(arg, &rl) && !is_whole_range_rl(rl)) {
1016                         sm_msg("info: passes param_value '%s' %d '$$' %s %s",
1017                                name, i, show_ranges(rl),
1018                                is_static(expr->fn) ? "static" : "global");
1019                 }
1020                 i++;
1021         } END_FOR_EACH_PTR(arg);
1022
1023         free_string(name);
1024 }
1025
1026 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1027 {
1028         struct range_list *rl = NULL;
1029         struct smatch_state *state;
1030         char fullname[256];
1031
1032         if (strncmp(key, "$$", 2))
1033                 return;
1034
1035         snprintf(fullname, 256, "%s%s", name, key + 2);
1036         parse_value_ranges_type(get_real_base_type(sym), value, &rl);
1037         state = alloc_estate_range_list(rl);
1038         set_state(SMATCH_EXTRA, fullname, sym, state);
1039 }
1040
1041 static void match_call_assign(struct expression *expr)
1042 {
1043         if (expr->op != '=')
1044                 return;
1045
1046         /* if we have a db set up this gets set in smatch_function_hooks.c */
1047         if (option_no_db)
1048                 set_extra_expr_mod(expr->left, extra_undefined(get_type(expr->left)));
1049 }
1050
1051 void register_smatch_extra(int id)
1052 {
1053         my_id = id;
1054
1055         add_merge_hook(my_id, &merge_func);
1056         add_unmatched_state_hook(my_id, &unmatched_state);
1057         add_hook(&unop_expr, OP_HOOK);
1058         add_hook(&asm_expr, ASM_HOOK);
1059         add_hook(&match_function_def, FUNC_DEF_HOOK);
1060         add_hook(&match_declarations, DECLARATION_HOOK);
1061         if (option_info) {
1062                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1063                 add_member_info_callback(my_id, struct_member_callback);
1064         }
1065         add_definition_db_callback(set_param_value, PARAM_VALUE);
1066 }
1067
1068 void register_smatch_extra_late(int id)
1069 {
1070         add_hook(&match_dereferences, DEREF_HOOK);
1071         add_hook(&match_pointer_as_array, OP_HOOK);
1072         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1073         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1074         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1075         add_hook(&match_assign, ASSIGNMENT_HOOK);
1076         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
1077 }