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 (estate_has_hard_max(sm->state))
 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 (estate_has_hard_max(sm->state))
 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, dummy;
 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_max(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_min(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 (get_hard_max(condition->right, &dummy))
 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_min(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         sval_t limit;
 355         struct smatch_state *state;
 356
 357         if (!iterator) {
 358                 while_count_down_after(sm, condition);
 359                 return;
 360         }
 361
 362         iter_expr = iterator->expression;
 363
 364         if (condition->type != EXPR_COMPARE)
 365                 return;
 366         if (iter_expr->op == SPECIAL_INCREMENT) {
 367                 limit = sval_binop(estate_max(sm->state), '+',
 368                                    sval_type_val(estate_type(sm->state), 1));
 369         } else {
 370                 limit = sval_binop(estate_min(sm->state), '-',
 371                                    sval_type_val(estate_type(sm->state), 1));
 372         }
 373         if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
 374                 if (iter_expr->op == SPECIAL_INCREMENT)
 375                         state = alloc_estate_range(estate_min(sm->state), limit);
 376                 else
 377                         state = alloc_estate_range(limit, estate_max(sm->state));
 378         } else {
 379                 state = alloc_estate(limit);
 380         }
 381         if (!estate_has_hard_max(sm->state))
 382                 estate_clear_hard_max(state);
 383         set_extra_mod(sm->name, sm->sym, state);
 384 }
 385
 386 static struct smatch_state *unmatched_state(struct sm_state *sm)
 387 {
 388         return extra_undefined(estate_type(sm->state));
 389 }
 390
 391 static void match_function_call(struct expression *expr)
 392 {
 393         struct expression *arg;
 394         struct expression *tmp;
 395
 396         FOR_EACH_PTR(expr->args, arg) {
 397                 tmp = strip_expr(arg);
 398                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 399                         remove_from_equiv_expr(tmp->unop);
 400                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined(get_type(tmp->unop)));
 401                 }
 402         } END_FOR_EACH_PTR(arg);
 403 }
 404
 405 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 406 {
 407         if (!one || !two)
 408                 return 0;
 409         if (one->type == SYM_PTR && two->type == SYM_PTR)
 410                 return 1;
 411         return types_equiv(one, two);
 412 }
 413
 414 static void match_assign(struct expression *expr)
 415 {
 416         struct range_list *rl = NULL;
 417         struct expression *left;
 418         struct expression *right;
 419         struct symbol *right_sym;
 420         char *right_name;
 421         struct symbol *sym;
 422         char *name;
 423         sval_t value;
 424         int known;
 425         sval_t right_min, right_max;
 426         sval_t tmp;
 427
 428         if (__is_condition_assign(expr))
 429                 return;
 430         left = strip_expr(expr->left);
 431         name = get_variable_from_expr(left, &sym);
 432         if (!name)
 433                 return;
 434         right = strip_parens(expr->right);
 435         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 436                 right = strip_parens(right->left);
 437
 438         if (expr->op == '=' && right->type == EXPR_CALL)
 439                 return;  /* these are handled in smatch_function_hooks.c */
 440
 441         right_name = get_variable_from_expr(right, &right_sym);
 442         if (expr->op == '=' && right_name && right_sym &&
 443             types_equiv_or_pointer(get_type(expr->left), get_type(expr->right))) {
 444                 set_equiv(left, right);
 445                 goto free;
 446         }
 447
 448         right_min = sval_type_min(get_type(expr->right));
 449         right_max = sval_type_max(get_type(expr->right));
 450
 451         known = get_implied_value(right, &value);
 452         switch (expr->op) {
 453         case '=': {
 454                 struct smatch_state *state;
 455
 456                 if (get_implied_range_list(right, &rl)) {
 457                         rl = cast_rl(get_type(expr->left), rl);
 458                         state = alloc_estate_range_list(rl);
 459                         if (get_hard_max(right, &tmp))
 460                                 estate_set_hard_max(state);
 461                 } else {
 462                         rl = whole_range_list(get_type(right));
 463                         rl = cast_rl(get_type(expr->left), rl);
 464                         state = alloc_estate_range_list(rl);
 465                 }
 466                 set_extra_mod(name, sym, state);
 467                 goto free;
 468         }
 469         case SPECIAL_ADD_ASSIGN:
 470                 if (get_implied_min(left, &tmp)) {
 471                         if (known)
 472                                 right_min = sval_binop(tmp, '+', value);
 473                         else
 474                                 right_min = tmp;
 475                 }
 476                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 477                         right_max = sval_binop(tmp, '+', value);
 478                 break;
 479         case SPECIAL_SUB_ASSIGN:
 480                 if (get_implied_max(left, &tmp)) {
 481                         if (known)
 482                                 right_max = sval_binop(tmp, '-', value);
 483                         else
 484                                 right_max = tmp;
 485                 }
 486                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 487                         right_min = sval_binop(tmp, '-', value);
 488                 break;
 489         }
 490         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 491                 rl = cast_rl(get_type(expr->left), alloc_range_list(right_min, right_max));
 492         else
 493                 rl = whole_range_list(get_type(expr->left));
 494         set_extra_mod(name, sym, alloc_estate_range_list(rl));
 495 free:
 496         free_string(right_name);
 497         free_string(name);
 498 }
 499
 500 static void reset_struct_members(struct sm_state *sm)
 501 {
 502         set_extra_mod(sm->name, sm->sym, extra_undefined(estate_type(sm->state)));
 503 }
 504
 505 static struct smatch_state *increment_state(struct smatch_state *state)
 506 {
 507         sval_t min = estate_min(state);
 508         sval_t max = estate_max(state);
 509
 510         if (!estate_ranges(state))
 511                 return NULL;
 512
 513         if (inside_loop())
 514                 max = sval_type_max(max.type);
 515
 516         if (!sval_is_min(min) && !sval_is_max(min))
 517                 min.value++;
 518         if (!sval_is_min(max) && !sval_is_max(max))
 519                 max.value++;
 520         return alloc_estate_range(min, max);
 521 }
 522
 523 static struct smatch_state *decrement_state(struct smatch_state *state)
 524 {
 525         sval_t min = estate_min(state);
 526         sval_t max = estate_max(state);
 527
 528         if (!estate_ranges(state))
 529                 return NULL;
 530
 531         if (inside_loop())
 532                 min = sval_type_min(min.type);
 533
 534         if (!sval_is_min(min) && !sval_is_max(min))
 535                 min.value--;
 536         if (!sval_is_min(max) && !sval_is_max(max))
 537                 max.value--;
 538         return alloc_estate_range(min, max);
 539 }
 540
 541 static void unop_expr(struct expression *expr)
 542 {
 543         struct smatch_state *state;
 544
 545         if (expr->smatch_flags & Handled)
 546                 return;
 547
 548         switch (expr->op) {
 549         case SPECIAL_INCREMENT:
 550                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 551                 state = increment_state(state);
 552                 if (!state)
 553                         state = extra_undefined(get_type(expr));
 554                 set_extra_expr_mod(expr->unop, state);
 555                 break;
 556         case SPECIAL_DECREMENT:
 557                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 558                 state = decrement_state(state);
 559                 if (!state)
 560                         state = extra_undefined(get_type(expr));
 561                 set_extra_expr_mod(expr->unop, state);
 562                 break;
 563         default:
 564                 return;
 565         }
 566 }
 567
 568 static void asm_expr(struct statement *stmt)
 569 {
 570
 571         struct expression *expr;
 572         int state = 0;
 573
 574         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 575                 switch (state) {
 576                 case 0: /* identifier */
 577                 case 1: /* constraint */
 578                         state++;
 579                         continue;
 580                 case 2: /* expression */
 581                         state = 0;
 582                         set_extra_expr_mod(expr, extra_undefined(get_type(expr)));
 583                         continue;
 584                 }
 585         } END_FOR_EACH_PTR(expr);
 586 }
 587
 588 static void delete_state_tracker(struct tracker *t)
 589 {
 590         remove_from_equiv(t->name, t->sym);
 591         delete_state(t->owner, t->name, t->sym);
 592 }
 593
 594 static void scoped_state_extra(const char *name, struct symbol *sym)
 595 {
 596         struct tracker *t;
 597
 598         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 599         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 600 }
 601
 602 static void match_declarations(struct symbol *sym)
 603 {
 604         const char *name;
 605
 606         if (sym->ident) {
 607                 name = sym->ident->name;
 608                 if (!sym->initializer) {
 609                         set_state(SMATCH_EXTRA, name, sym, extra_undefined(get_real_base_type(sym)));
 610                         scoped_state_extra(name, sym);
 611                 }
 612         }
 613 }
 614
 615 static void check_dereference(struct expression *expr)
 616 {
 617         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 618 }
 619
 620 static void match_dereferences(struct expression *expr)
 621 {
 622         if (expr->type != EXPR_PREOP)
 623                 return;
 624         check_dereference(expr->unop);
 625 }
 626
 627 static void match_pointer_as_array(struct expression *expr)
 628 {
 629         if (!is_array(expr))
 630                 return;
 631         check_dereference(expr->unop->left);
 632 }
 633
 634 static void set_param_dereferenced(struct expression *arg, char *unused)
 635 {
 636         check_dereference(arg);
 637 }
 638
 639 static void match_function_def(struct symbol *sym)
 640 {
 641         struct symbol *arg;
 642
 643         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 644                 if (!arg->ident)
 645                         continue;
 646                 set_state(my_id, arg->ident->name, arg, extra_undefined(get_real_base_type(arg)));
 647         } END_FOR_EACH_PTR(arg);
 648 }
 649
 650 static int match_func_comparison(struct expression *expr)
 651 {
 652         struct expression *left = strip_expr(expr->left);
 653         struct expression *right = strip_expr(expr->right);
 654         sval_t sval;
 655
 656         if (left->type == EXPR_CALL) {
 657                 if (!get_implied_value(right, &sval))
 658                         return 1;
 659                 function_comparison(expr->op, left, sval, 1);
 660                 return 1;
 661         }
 662
 663         if (right->type == EXPR_CALL) {
 664                 if (!get_implied_value(left, &sval))
 665                         return 1;
 666                 function_comparison(expr->op, right, sval, 0);
 667                 return 1;
 668         }
 669
 670         return 0;
 671 }
 672
 673 static sval_t add_one(sval_t sval)
 674 {
 675         sval.value++;
 676         return sval;
 677 }
 678
 679 static sval_t sub_one(sval_t sval)
 680 {
 681         sval.value--;
 682         return sval;
 683 }
 684
 685 static void match_comparison(struct expression *expr)
 686 {
 687         struct expression *left = strip_expr(expr->left);
 688         struct expression *right = strip_expr(expr->right);
 689         struct symbol *type;
 690         struct range_list *left_orig;
 691         struct range_list *left_true;
 692         struct range_list *left_false;
 693         struct range_list *right_orig;
 694         struct range_list *right_true;
 695         struct range_list *right_false;
 696         struct smatch_state *left_true_state;
 697         struct smatch_state *left_false_state;
 698         struct smatch_state *right_true_state;
 699         struct smatch_state *right_false_state;
 700         sval_t min, max, dummy;
 701         int left_postop = 0;
 702         int right_postop = 0;
 703
 704         if (match_func_comparison(expr))
 705                 return;
 706
 707         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 708                 if (left->type == EXPR_POSTOP) {
 709                         left->smatch_flags |= Handled;
 710                         left_postop = left->op;
 711                 }
 712                 left = strip_expr(left->unop);
 713         }
 714         while (left->type == EXPR_ASSIGNMENT)
 715                 left = strip_expr(left->left);
 716
 717         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 718                 if (right->type == EXPR_POSTOP) {
 719                         right->smatch_flags |= Handled;
 720                         right_postop = right->op;
 721                 }
 722                 right = strip_expr(right->unop);
 723         }
 724
 725         type = get_type(expr);
 726         if (!type)
 727                 type = &llong_ctype;
 728
 729         if (get_implied_range_list(left, &left_orig)) {
 730                 left_orig = cast_rl(type, left_orig);
 731         } else {
 732                 min = sval_type_min(get_type(left));
 733                 max = sval_type_max(get_type(left));
 734                 left_orig = cast_rl(type, alloc_range_list(min, max));
 735         }
 736
 737         if (get_implied_range_list(right, &right_orig)) {
 738                 right_orig = cast_rl(type, right_orig);
 739         } else {
 740                 min = sval_type_min(get_type(right));
 741                 max = sval_type_max(get_type(right));
 742                 right_orig = cast_rl(type, alloc_range_list(min, max));
 743         }
 744         min = sval_type_min(type);
 745         max = sval_type_max(type);
 746
 747         left_true = clone_range_list(left_orig);
 748         left_false = clone_range_list(left_orig);
 749         right_true = clone_range_list(right_orig);
 750         right_false = clone_range_list(right_orig);
 751
 752         switch (expr->op) {
 753         case '<':
 754         case SPECIAL_UNSIGNED_LT:
 755                 if (!sval_is_max(rl_max(right_orig))) {
 756                         left_true = remove_range(left_orig, rl_max(right_orig), max);
 757                 }
 758                 if (!sval_is_min(rl_min(right_orig))) {
 759                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 760                 }
 761
 762                 if (!sval_is_min(rl_min(left_orig)))
 763                         right_true = remove_range(right_orig, min, rl_min(left_orig));
 764                 if (!sval_is_max(rl_max(left_orig)))
 765                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 766                 break;
 767         case SPECIAL_UNSIGNED_LTE:
 768         case SPECIAL_LTE:
 769                 if (!sval_is_max(rl_max(right_orig)))
 770                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 771                 if (!sval_is_min(rl_min(right_orig)))
 772                         left_false = remove_range(left_orig, min, rl_min(right_orig));
 773
 774                 if (!sval_is_min(rl_min(left_orig)))
 775                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 776                 if (!sval_is_max(rl_max(left_orig)))
 777                         right_false = remove_range(right_orig, rl_max(left_orig), max);
 778
 779                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 780                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 781                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 782                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 783                 break;
 784         case SPECIAL_EQUAL:
 785                 if (!sval_is_max(rl_max(right_orig))) {
 786                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 787                 }
 788                 if (!sval_is_min(rl_min(right_orig))) {
 789                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 790                 }
 791                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 792                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 793
 794                 if (!sval_is_max(rl_max(left_orig)))
 795                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 796                 if (!sval_is_min(rl_min(left_orig)))
 797                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 798                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 799                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 800                 break;
 801         case SPECIAL_UNSIGNED_GTE:
 802         case SPECIAL_GTE:
 803                 if (!sval_is_min(rl_min(right_orig)))
 804                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 805                 if (!sval_is_max(rl_max(right_orig)))
 806                         left_false = remove_range(left_orig, rl_max(right_orig), max);
 807
 808                 if (!sval_is_max(rl_max(left_orig)))
 809                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 810                 if (!sval_is_min(rl_min(left_orig)))
 811                         right_false = remove_range(right_orig, min, rl_min(left_orig));
 812
 813                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 814                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 815                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 816                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 817                 break;
 818         case '>':
 819         case SPECIAL_UNSIGNED_GT:
 820                 if (!sval_is_min(rl_min(right_orig)))
 821                         left_true = remove_range(left_orig, min, rl_min(right_orig));
 822                 if (!sval_is_max(rl_max(right_orig)))
 823                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 824
 825                 if (!sval_is_max(rl_max(left_orig)))
 826                         right_true = remove_range(right_orig, rl_max(left_orig), max);
 827                 if (!sval_is_min(rl_min(left_orig)))
 828                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 829                 break;
 830         case SPECIAL_NOTEQUAL:
 831                 if (!sval_is_max(rl_max(right_orig)))
 832                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 833                 if (!sval_is_min(rl_min(right_orig)))
 834                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 835                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 836                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 837
 838                 if (!sval_is_max(rl_max(left_orig)))
 839                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 840                 if (!sval_is_min(rl_min(left_orig)))
 841                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 842                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 843                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 844                 break;
 845         default:
 846                 return;
 847         }
 848
 849         left_true_state = alloc_estate_range_list(cast_rl(get_type(left), left_true));
 850         left_false_state = alloc_estate_range_list(cast_rl(get_type(left), left_false));
 851         right_true_state = alloc_estate_range_list(cast_rl(get_type(right), right_true));
 852         right_false_state = alloc_estate_range_list(cast_rl(get_type(right), right_false));
 853
 854         switch (expr->op) {
 855         case '<':
 856         case SPECIAL_UNSIGNED_LT:
 857         case SPECIAL_UNSIGNED_LTE:
 858         case SPECIAL_LTE:
 859                 if (get_hard_max(right, &dummy))
 860                         estate_set_hard_max(left_true_state);
 861                 if (get_hard_max(left, &dummy))
 862                         estate_set_hard_max(right_false_state);
 863                 break;
 864         case '>':
 865         case SPECIAL_UNSIGNED_GT:
 866         case SPECIAL_UNSIGNED_GTE:
 867         case SPECIAL_GTE:
 868                 if (get_hard_max(left, &dummy))
 869                         estate_set_hard_max(right_true_state);
 870                 if (get_hard_max(right, &dummy))
 871                         estate_set_hard_max(left_false_state);
 872                 break;
 873         }
 874
 875         if (get_hard_max(left, &dummy)) {
 876                 estate_set_hard_max(left_true_state);
 877                 estate_set_hard_max(left_false_state);
 878         }
 879         if (get_hard_max(right, &dummy)) {
 880                 estate_set_hard_max(right_true_state);
 881                 estate_set_hard_max(right_false_state);
 882         }
 883
 884         if (left_postop == SPECIAL_INCREMENT) {
 885                 left_true_state = increment_state(left_true_state);
 886                 left_false_state = increment_state(left_false_state);
 887         }
 888         if (left_postop == SPECIAL_DECREMENT) {
 889                 left_true_state = decrement_state(left_true_state);
 890                 left_false_state = decrement_state(left_false_state);
 891         }
 892         if (right_postop == SPECIAL_INCREMENT) {
 893                 right_true_state = increment_state(right_true_state);
 894                 right_false_state = increment_state(right_false_state);
 895         }
 896         if (right_postop == SPECIAL_DECREMENT) {
 897                 right_true_state = decrement_state(right_true_state);
 898                 right_false_state = decrement_state(right_false_state);
 899         }
 900
 901         set_extra_expr_true_false(left, left_true_state, left_false_state);
 902         set_extra_expr_true_false(right, right_true_state, right_false_state);
 903 }
 904
 905 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 906 void __extra_match_condition(struct expression *expr)
 907 {
 908         struct symbol *sym;
 909         char *name;
 910         struct smatch_state *pre_state;
 911         struct smatch_state *true_state;
 912         struct smatch_state *false_state;
 913
 914         expr = strip_expr(expr);
 915         switch (expr->type) {
 916         case EXPR_CALL:
 917                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 918                 return;
 919         case EXPR_PREOP:
 920         case EXPR_SYMBOL:
 921         case EXPR_DEREF: {
 922                 sval_t zero;
 923
 924                 zero = sval_blank(expr);
 925                 zero.value = 0;
 926
 927                 name = get_variable_from_expr(expr, &sym);
 928                 if (!name)
 929                         return;
 930                 pre_state = get_state(my_id, name, sym);
 931                 true_state = add_filter(pre_state, zero);
 932                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 933                         false_state = alloc_estate(zero);
 934                 else
 935                         false_state = alloc_estate_empty();
 936                 set_extra_true_false(name, sym, true_state, false_state);
 937                 free_string(name);
 938                 return;
 939         }
 940         case EXPR_COMPARE:
 941                 match_comparison(expr);
 942                 return;
 943         case EXPR_ASSIGNMENT:
 944                 __extra_match_condition(expr->left);
 945                 return;
 946         }
 947 }
 948
 949 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 950 int implied_not_equal(struct expression *expr, long long val)
 951 {
 952         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 953 }
 954
 955 int is_whole_range(struct smatch_state *state)
 956 {
 957         return is_whole_range_rl(estate_ranges(state));
 958 }
 959
 960 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 961 {
 962         if (is_whole_range(state))
 963                 return;
 964         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 965 }
 966
 967 static void match_call_info(struct expression *expr)
 968 {
 969         struct range_list *rl = NULL;
 970         struct expression *arg;
 971         struct symbol *type;
 972         char *name;
 973         int i = 0;
 974
 975         name = get_fnptr_name(expr->fn);
 976         if (!name)
 977                 return;
 978
 979         FOR_EACH_PTR(expr->args, arg) {
 980                 type = get_arg_type(expr->fn, i);
 981
 982                 if (get_implied_range_list(arg, &rl))
 983                         rl = cast_rl(type, rl);
 984                 else
 985                         rl = whole_range_list(type);
 986
 987                 sm_msg("info: passes param_value '%s' %d '$$' %s %s",
 988                        name, i, show_ranges(rl),
 989                        is_static(expr->fn) ? "static" : "global");
 990                 i++;
 991         } END_FOR_EACH_PTR(arg);
 992
 993         free_string(name);
 994 }
 995
 996 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
 997 {
 998         struct range_list *rl = NULL;
 999         struct smatch_state *state;
1000         struct symbol *type;
1001         char fullname[256];
1002
1003         if (strncmp(key, "$$", 2))
1004                 return;
1005
1006         snprintf(fullname, 256, "%s%s", name, key + 2);
1007         type = get_param_type_from_key(sym, key);
1008         parse_value_ranges_type(type, value, &rl);
1009         state = alloc_estate_range_list(rl);
1010         set_state(SMATCH_EXTRA, fullname, sym, state);
1011 }
1012
1013 void register_smatch_extra(int id)
1014 {
1015         my_id = id;
1016
1017         add_merge_hook(my_id, &merge_func);
1018         add_unmatched_state_hook(my_id, &unmatched_state);
1019         add_hook(&unop_expr, OP_HOOK);
1020         add_hook(&asm_expr, ASM_HOOK);
1021         add_hook(&match_function_def, FUNC_DEF_HOOK);
1022         add_hook(&match_declarations, DECLARATION_HOOK);
1023         if (option_info) {
1024                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1025                 add_member_info_callback(my_id, struct_member_callback);
1026         }
1027         add_definition_db_callback(set_param_value, PARAM_VALUE);
1028 }
1029
1030 void register_smatch_extra_late(int id)
1031 {
1032         add_hook(&match_dereferences, DEREF_HOOK);
1033         add_hook(&match_pointer_as_array, OP_HOOK);
1034         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1035         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1036         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1037         add_hook(&match_assign, ASSIGNMENT_HOOK);
1038 }