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 sm_state *handle_canonical_while_count_down(struct statement *loop)
 148 {
 149         struct expression *iter_var;
 150         struct expression *condition;
 151         struct sm_state *sm;
 152         struct smatch_state *estate;
 153         sval_t start;
 154
 155         condition = strip_expr(loop->iterator_pre_condition);
 156         if (!condition)
 157                 return NULL;
 158         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 159                 return NULL;
 160         if (condition->op != SPECIAL_DECREMENT)
 161                 return NULL;
 162
 163         iter_var = condition->unop;
 164         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 165         if (!sm)
 166                 return NULL;
 167         if (sval_cmp_val(estate_min(sm->state), 0) < 0)
 168                 return NULL;
 169         start = estate_max(sm->state);
 170         if  (sval_cmp_val(start, 0) <= 0)
 171                 return NULL;
 172         if (!sval_is_max(start))
 173                 start.value--;
 174
 175         if (condition->type == EXPR_PREOP) {
 176                 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
 177                 if (estate_has_hard_max(sm->state))
 178                         estate_set_hard_max(estate);
 179                 set_extra_expr_mod(iter_var, estate);
 180         }
 181         if (condition->type == EXPR_POSTOP) {
 182                 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
 183                 if (estate_has_hard_max(sm->state))
 184                         estate_set_hard_max(estate);
 185                 set_extra_expr_mod(iter_var, estate);
 186         }
 187         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 188 }
 189
 190 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 191                                                 struct expression *condition)
 192 {
 193         struct expression *iter_var;
 194         struct sm_state *sm;
 195         struct smatch_state *estate;
 196         sval_t start, end, dummy;
 197
 198         iter_var = iter_expr->unop;
 199         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 200         if (!sm)
 201                 return NULL;
 202         if (!estate_get_single_value(sm->state, &start))
 203                 return NULL;
 204         if (!get_implied_max(condition->right, &end))
 205                 end = sval_type_max(get_type(iter_var));
 206
 207         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 208                 return NULL;
 209
 210         switch (condition->op) {
 211         case SPECIAL_NOTEQUAL:
 212         case '<':
 213                 if (!sval_is_min(end))
 214                         end.value--;
 215                 break;
 216         case SPECIAL_LTE:
 217                 break;
 218         default:
 219                 return NULL;
 220         }
 221         if (sval_cmp(end, start) < 0)
 222                 return NULL;
 223         estate = alloc_estate_range(start, end);
 224         if (get_hard_max(condition->right, &dummy))
 225                 estate_set_hard_max(estate);
 226         set_extra_expr_mod(iter_var, estate);
 227         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 228 }
 229
 230 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 231                                                 struct expression *condition)
 232 {
 233         struct expression *iter_var;
 234         struct sm_state *sm;
 235         struct smatch_state *estate;
 236         sval_t start, end;
 237
 238         iter_var = iter_expr->unop;
 239         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 240         if (!sm)
 241                 return NULL;
 242         if (!estate_get_single_value(sm->state, &start))
 243                 return NULL;
 244         if (!get_implied_min(condition->right, &end))
 245                 end = sval_type_min(get_type(iter_var));
 246         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 247                 return NULL;
 248
 249         switch (condition->op) {
 250         case SPECIAL_NOTEQUAL:
 251         case '>':
 252                 if (!sval_is_min(end) && !sval_is_max(end))
 253                         end.value++;
 254                 break;
 255         case SPECIAL_GTE:
 256                 break;
 257         default:
 258                 return NULL;
 259         }
 260         if (sval_cmp(end, start) > 0)
 261                 return NULL;
 262         estate = alloc_estate_range(end, start);
 263         estate_set_hard_max(estate);
 264         set_extra_expr_mod(iter_var, estate);
 265         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 266 }
 267
 268 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 269 {
 270         struct expression *iter_expr;
 271         struct expression *condition;
 272
 273         if (!loop->iterator_post_statement)
 274                 return NULL;
 275         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 276                 return NULL;
 277         iter_expr = loop->iterator_post_statement->expression;
 278         if (!loop->iterator_pre_condition)
 279                 return NULL;
 280         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 281                 return NULL;
 282         condition = loop->iterator_pre_condition;
 283
 284         if (iter_expr->op == SPECIAL_INCREMENT)
 285                 return handle_canonical_for_inc(iter_expr, condition);
 286         if (iter_expr->op == SPECIAL_DECREMENT)
 287                 return handle_canonical_for_dec(iter_expr, condition);
 288         return NULL;
 289 }
 290
 291 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 292 {
 293         struct sm_state *ret;
 294
 295         __push_fake_cur_slist();
 296         if (!loop->iterator_post_statement)
 297                 ret = handle_canonical_while_count_down(loop);
 298         else
 299                 ret = handle_canonical_for_loops(loop);
 300         *slist = __pop_fake_cur_slist();
 301         return ret;
 302 }
 303
 304 int __iterator_unchanged(struct sm_state *sm)
 305 {
 306         if (!sm)
 307                 return 0;
 308         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 309                 return 1;
 310         return 0;
 311 }
 312
 313 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 314 {
 315         sval_t after_value;
 316
 317         /* paranoid checking.  prolly not needed */
 318         condition = strip_expr(condition);
 319         if (!condition)
 320                 return;
 321         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 322                 return;
 323         if (condition->op != SPECIAL_DECREMENT)
 324                 return;
 325         after_value = estate_min(sm->state);
 326         after_value.value--;
 327         set_extra_mod(sm->name, sm->sym, alloc_estate(after_value));
 328 }
 329
 330 void __extra_pre_loop_hook_after(struct sm_state *sm,
 331                                 struct statement *iterator,
 332                                 struct expression *condition)
 333 {
 334         struct expression *iter_expr;
 335         sval_t limit;
 336         struct smatch_state *state;
 337
 338         if (!iterator) {
 339                 while_count_down_after(sm, condition);
 340                 return;
 341         }
 342
 343         iter_expr = iterator->expression;
 344
 345         if (condition->type != EXPR_COMPARE)
 346                 return;
 347         if (iter_expr->op == SPECIAL_INCREMENT) {
 348                 limit = sval_binop(estate_max(sm->state), '+',
 349                                    sval_type_val(estate_type(sm->state), 1));
 350         } else {
 351                 limit = sval_binop(estate_min(sm->state), '-',
 352                                    sval_type_val(estate_type(sm->state), 1));
 353         }
 354         if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
 355                 if (iter_expr->op == SPECIAL_INCREMENT)
 356                         state = alloc_estate_range(estate_min(sm->state), limit);
 357                 else
 358                         state = alloc_estate_range(limit, estate_max(sm->state));
 359         } else {
 360                 state = alloc_estate(limit);
 361         }
 362         if (!estate_has_hard_max(sm->state))
 363                 estate_clear_hard_max(state);
 364         set_extra_mod(sm->name, sm->sym, state);
 365 }
 366
 367 static struct smatch_state *unmatched_state(struct sm_state *sm)
 368 {
 369         return extra_undefined(estate_type(sm->state));
 370 }
 371
 372 static void match_function_call(struct expression *expr)
 373 {
 374         struct expression *arg;
 375         struct expression *tmp;
 376
 377         FOR_EACH_PTR(expr->args, arg) {
 378                 tmp = strip_expr(arg);
 379                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 380                         remove_from_equiv_expr(tmp->unop);
 381                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined(get_type(tmp->unop)));
 382                 }
 383         } END_FOR_EACH_PTR(arg);
 384 }
 385
 386 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
 387 {
 388         if (!one || !two)
 389                 return 0;
 390         if (one->type == SYM_PTR && two->type == SYM_PTR)
 391                 return 1;
 392         return types_equiv(one, two);
 393 }
 394
 395 static void match_assign(struct expression *expr)
 396 {
 397         struct range_list *rl = NULL;
 398         struct expression *left;
 399         struct expression *right;
 400         struct symbol *right_sym;
 401         char *right_name = NULL;
 402         struct symbol *sym;
 403         char *name;
 404         sval_t value;
 405         int known;
 406         sval_t right_min, right_max;
 407         sval_t tmp;
 408
 409         if (is_condition(expr->right))
 410                 return;
 411         left = strip_expr(expr->left);
 412         name = get_variable_from_expr(left, &sym);
 413         if (!name)
 414                 return;
 415         right = strip_parens(expr->right);
 416         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 417                 right = strip_parens(right->left);
 418
 419         if (expr->op == '=' && right->type == EXPR_CALL)
 420                 goto free;  /* these are handled in smatch_function_hooks.c */
 421
 422         right_name = get_variable_from_expr(right, &right_sym);
 423         if (expr->op == '=' && right_name && right_sym &&
 424             types_equiv_or_pointer(get_type(expr->left), get_type(expr->right))) {
 425                 set_equiv(left, right);
 426                 goto free;
 427         }
 428
 429         right_min = sval_type_min(get_type(expr->right));
 430         right_max = sval_type_max(get_type(expr->right));
 431
 432         known = get_implied_value(right, &value);
 433         switch (expr->op) {
 434         case '=': {
 435                 struct smatch_state *state;
 436
 437                 if (get_implied_range_list(right, &rl)) {
 438                         rl = cast_rl(get_type(expr->left), rl);
 439                         state = alloc_estate_range_list(rl);
 440                         if (get_hard_max(right, &tmp))
 441                                 estate_set_hard_max(state);
 442                 } else {
 443                         rl = whole_range_list(get_type(right));
 444                         rl = cast_rl(get_type(expr->left), rl);
 445                         state = alloc_estate_range_list(rl);
 446                 }
 447                 set_extra_mod(name, sym, state);
 448                 goto free;
 449         }
 450         case SPECIAL_ADD_ASSIGN:
 451                 if (get_implied_min(left, &tmp)) {
 452                         if (known)
 453                                 right_min = sval_binop(tmp, '+', value);
 454                         else
 455                                 right_min = tmp;
 456                 }
 457                 if (!inside_loop() && known && get_implied_max(left, &tmp))
 458                         right_max = sval_binop(tmp, '+', value);
 459                 break;
 460         case SPECIAL_SUB_ASSIGN:
 461                 if (get_implied_max(left, &tmp)) {
 462                         if (known)
 463                                 right_max = sval_binop(tmp, '-', value);
 464                         else
 465                                 right_max = tmp;
 466                 }
 467                 if (!inside_loop() && known && get_implied_min(left, &tmp))
 468                         right_min = sval_binop(tmp, '-', value);
 469                 break;
 470         }
 471         if (!sval_is_min(right_min) || !sval_is_max(right_max))
 472                 rl = cast_rl(get_type(expr->left), alloc_range_list(right_min, right_max));
 473         else
 474                 rl = whole_range_list(get_type(expr->left));
 475         set_extra_mod(name, sym, alloc_estate_range_list(rl));
 476 free:
 477         free_string(right_name);
 478         free_string(name);
 479 }
 480
 481 static void reset_struct_members(struct sm_state *sm)
 482 {
 483         set_extra_mod(sm->name, sm->sym, extra_undefined(estate_type(sm->state)));
 484 }
 485
 486 static struct smatch_state *increment_state(struct smatch_state *state)
 487 {
 488         sval_t min = estate_min(state);
 489         sval_t max = estate_max(state);
 490
 491         if (!estate_ranges(state))
 492                 return NULL;
 493
 494         if (inside_loop())
 495                 max = sval_type_max(max.type);
 496
 497         if (!sval_is_min(min) && !sval_is_max(min))
 498                 min.value++;
 499         if (!sval_is_min(max) && !sval_is_max(max))
 500                 max.value++;
 501         return alloc_estate_range(min, max);
 502 }
 503
 504 static struct smatch_state *decrement_state(struct smatch_state *state)
 505 {
 506         sval_t min = estate_min(state);
 507         sval_t max = estate_max(state);
 508
 509         if (!estate_ranges(state))
 510                 return NULL;
 511
 512         if (inside_loop())
 513                 min = sval_type_min(min.type);
 514
 515         if (!sval_is_min(min) && !sval_is_max(min))
 516                 min.value--;
 517         if (!sval_is_min(max) && !sval_is_max(max))
 518                 max.value--;
 519         return alloc_estate_range(min, max);
 520 }
 521
 522 static void unop_expr(struct expression *expr)
 523 {
 524         struct smatch_state *state;
 525
 526         if (expr->smatch_flags & Handled)
 527                 return;
 528
 529         switch (expr->op) {
 530         case SPECIAL_INCREMENT:
 531                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 532                 state = increment_state(state);
 533                 if (!state)
 534                         state = extra_undefined(get_type(expr));
 535                 set_extra_expr_mod(expr->unop, state);
 536                 break;
 537         case SPECIAL_DECREMENT:
 538                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 539                 state = decrement_state(state);
 540                 if (!state)
 541                         state = extra_undefined(get_type(expr));
 542                 set_extra_expr_mod(expr->unop, state);
 543                 break;
 544         default:
 545                 return;
 546         }
 547 }
 548
 549 static void asm_expr(struct statement *stmt)
 550 {
 551
 552         struct expression *expr;
 553         int state = 0;
 554
 555         FOR_EACH_PTR(stmt->asm_outputs, expr) {
 556                 switch (state) {
 557                 case 0: /* identifier */
 558                 case 1: /* constraint */
 559                         state++;
 560                         continue;
 561                 case 2: /* expression */
 562                         state = 0;
 563                         set_extra_expr_mod(expr, extra_undefined(get_type(expr)));
 564                         continue;
 565                 }
 566         } END_FOR_EACH_PTR(expr);
 567 }
 568
 569 static void delete_state_tracker(struct tracker *t)
 570 {
 571         remove_from_equiv(t->name, t->sym);
 572         delete_state(t->owner, t->name, t->sym);
 573 }
 574
 575 static void scoped_state_extra(const char *name, struct symbol *sym)
 576 {
 577         struct tracker *t;
 578
 579         t = alloc_tracker(SMATCH_EXTRA, name, sym);
 580         add_scope_hook((scope_hook *)&delete_state_tracker, t);
 581 }
 582
 583 static void match_declarations(struct symbol *sym)
 584 {
 585         const char *name;
 586
 587         if (sym->ident) {
 588                 name = sym->ident->name;
 589                 if (!sym->initializer) {
 590                         set_state(SMATCH_EXTRA, name, sym, extra_undefined(get_real_base_type(sym)));
 591                         scoped_state_extra(name, sym);
 592                 }
 593         }
 594 }
 595
 596 static void check_dereference(struct expression *expr)
 597 {
 598         set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
 599 }
 600
 601 static void match_dereferences(struct expression *expr)
 602 {
 603         if (expr->type != EXPR_PREOP)
 604                 return;
 605         check_dereference(expr->unop);
 606 }
 607
 608 static void match_pointer_as_array(struct expression *expr)
 609 {
 610         if (!is_array(expr))
 611                 return;
 612         check_dereference(expr->unop->left);
 613 }
 614
 615 static void set_param_dereferenced(struct expression *arg, char *unused)
 616 {
 617         check_dereference(arg);
 618 }
 619
 620 static void match_function_def(struct symbol *sym)
 621 {
 622         struct symbol *arg;
 623
 624         FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
 625                 if (!arg->ident)
 626                         continue;
 627                 set_state(my_id, arg->ident->name, arg, extra_undefined(get_real_base_type(arg)));
 628         } END_FOR_EACH_PTR(arg);
 629 }
 630
 631 static int match_func_comparison(struct expression *expr)
 632 {
 633         struct expression *left = strip_expr(expr->left);
 634         struct expression *right = strip_expr(expr->right);
 635         sval_t sval;
 636
 637         if (left->type == EXPR_CALL) {
 638                 if (!get_implied_value(right, &sval))
 639                         return 1;
 640                 function_comparison(expr->op, left, sval, 1);
 641                 return 1;
 642         }
 643
 644         if (right->type == EXPR_CALL) {
 645                 if (!get_implied_value(left, &sval))
 646                         return 1;
 647                 function_comparison(expr->op, right, sval, 0);
 648                 return 1;
 649         }
 650
 651         return 0;
 652 }
 653
 654 static sval_t add_one(sval_t sval)
 655 {
 656         sval.value++;
 657         return sval;
 658 }
 659
 660 static sval_t sub_one(sval_t sval)
 661 {
 662         sval.value--;
 663         return sval;
 664 }
 665
 666 static void match_comparison(struct expression *expr)
 667 {
 668         struct expression *left = strip_expr(expr->left);
 669         struct expression *right = strip_expr(expr->right);
 670         struct symbol *type;
 671         struct range_list *left_orig;
 672         struct range_list *left_true;
 673         struct range_list *left_false;
 674         struct range_list *right_orig;
 675         struct range_list *right_true;
 676         struct range_list *right_false;
 677         struct smatch_state *left_true_state;
 678         struct smatch_state *left_false_state;
 679         struct smatch_state *right_true_state;
 680         struct smatch_state *right_false_state;
 681         sval_t min, max, dummy;
 682         int left_postop = 0;
 683         int right_postop = 0;
 684
 685         if (match_func_comparison(expr))
 686                 return;
 687
 688         if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
 689                 if (left->type == EXPR_POSTOP) {
 690                         left->smatch_flags |= Handled;
 691                         left_postop = left->op;
 692                 }
 693                 left = strip_expr(left->unop);
 694         }
 695         while (left->type == EXPR_ASSIGNMENT)
 696                 left = strip_expr(left->left);
 697
 698         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 699                 if (right->type == EXPR_POSTOP) {
 700                         right->smatch_flags |= Handled;
 701                         right_postop = right->op;
 702                 }
 703                 right = strip_expr(right->unop);
 704         }
 705
 706         type = get_type(expr);
 707         if (!type)
 708                 type = &llong_ctype;
 709
 710         if (get_implied_range_list(left, &left_orig)) {
 711                 left_orig = cast_rl(type, left_orig);
 712         } else {
 713                 min = sval_type_min(get_type(left));
 714                 max = sval_type_max(get_type(left));
 715                 left_orig = cast_rl(type, alloc_range_list(min, max));
 716         }
 717
 718         if (get_implied_range_list(right, &right_orig)) {
 719                 right_orig = cast_rl(type, right_orig);
 720         } else {
 721                 min = sval_type_min(get_type(right));
 722                 max = sval_type_max(get_type(right));
 723                 right_orig = cast_rl(type, alloc_range_list(min, max));
 724         }
 725         min = sval_type_min(type);
 726         max = sval_type_max(type);
 727
 728         left_true = clone_range_list(left_orig);
 729         left_false = clone_range_list(left_orig);
 730         right_true = clone_range_list(right_orig);
 731         right_false = clone_range_list(right_orig);
 732
 733         switch (expr->op) {
 734         case '<':
 735         case SPECIAL_UNSIGNED_LT:
 736                 left_true = remove_range(left_orig, rl_max(right_orig), max);
 737                 if (!sval_is_min(rl_min(right_orig))) {
 738                         left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 739                 }
 740
 741                 right_true = remove_range(right_orig, min, rl_min(left_orig));
 742                 if (!sval_is_max(rl_max(left_orig)))
 743                         right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 744                 break;
 745         case SPECIAL_UNSIGNED_LTE:
 746         case SPECIAL_LTE:
 747                 if (!sval_is_max(rl_max(right_orig)))
 748                         left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 749                 left_false = remove_range(left_orig, min, rl_min(right_orig));
 750
 751                 if (!sval_is_min(rl_min(left_orig)))
 752                         right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 753                 right_false = remove_range(right_orig, rl_max(left_orig), max);
 754
 755                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 756                         left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
 757                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 758                         right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
 759                 break;
 760         case SPECIAL_EQUAL:
 761                 if (!sval_is_max(rl_max(right_orig))) {
 762                         left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
 763                 }
 764                 if (!sval_is_min(rl_min(right_orig))) {
 765                         left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
 766                 }
 767                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 768                         left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 769
 770                 if (!sval_is_max(rl_max(left_orig)))
 771                         right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
 772                 if (!sval_is_min(rl_min(left_orig)))
 773                         right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
 774                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 775                         right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 776                 break;
 777         case SPECIAL_UNSIGNED_GTE:
 778         case SPECIAL_GTE:
 779                 if (!sval_is_min(rl_min(right_orig)))
 780                         left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
 781                 left_false = remove_range(left_orig, rl_max(right_orig), max);
 782
 783                 if (!sval_is_max(rl_max(left_orig)))
 784                         right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
 785                 right_false = remove_range(right_orig, min, rl_min(left_orig));
 786
 787                 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
 788                         right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
 789                 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
 790                         left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
 791                 break;
 792         case '>':
 793         case SPECIAL_UNSIGNED_GT:
 794                 left_true = remove_range(left_orig, min, rl_min(right_orig));
 795                 if (!sval_is_max(rl_max(right_orig)))
 796                         left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
 797
 798                 right_true = remove_range(right_orig, rl_max(left_orig), max);
 799                 if (!sval_is_min(rl_min(left_orig)))
 800                         right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
 801                 break;
 802         case SPECIAL_NOTEQUAL:
 803                 if (!sval_is_max(rl_max(right_orig)))
 804                         left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
 805                 if (!sval_is_min(rl_min(right_orig)))
 806                         left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
 807                 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
 808                         left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
 809
 810                 if (!sval_is_max(rl_max(left_orig)))
 811                         right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
 812                 if (!sval_is_min(rl_min(left_orig)))
 813                         right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
 814                 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
 815                         right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
 816                 break;
 817         default:
 818                 return;
 819         }
 820
 821         left_true_state = alloc_estate_range_list(cast_rl(get_type(left), left_true));
 822         left_false_state = alloc_estate_range_list(cast_rl(get_type(left), left_false));
 823         right_true_state = alloc_estate_range_list(cast_rl(get_type(right), right_true));
 824         right_false_state = alloc_estate_range_list(cast_rl(get_type(right), right_false));
 825
 826         switch (expr->op) {
 827         case '<':
 828         case SPECIAL_UNSIGNED_LT:
 829         case SPECIAL_UNSIGNED_LTE:
 830         case SPECIAL_LTE:
 831                 if (get_hard_max(right, &dummy))
 832                         estate_set_hard_max(left_true_state);
 833                 if (get_hard_max(left, &dummy))
 834                         estate_set_hard_max(right_false_state);
 835                 break;
 836         case '>':
 837         case SPECIAL_UNSIGNED_GT:
 838         case SPECIAL_UNSIGNED_GTE:
 839         case SPECIAL_GTE:
 840                 if (get_hard_max(left, &dummy))
 841                         estate_set_hard_max(right_true_state);
 842                 if (get_hard_max(right, &dummy))
 843                         estate_set_hard_max(left_false_state);
 844                 break;
 845         }
 846
 847         if (get_hard_max(left, &dummy)) {
 848                 estate_set_hard_max(left_true_state);
 849                 estate_set_hard_max(left_false_state);
 850         }
 851         if (get_hard_max(right, &dummy)) {
 852                 estate_set_hard_max(right_true_state);
 853                 estate_set_hard_max(right_false_state);
 854         }
 855
 856         if (left_postop == SPECIAL_INCREMENT) {
 857                 left_true_state = increment_state(left_true_state);
 858                 left_false_state = increment_state(left_false_state);
 859         }
 860         if (left_postop == SPECIAL_DECREMENT) {
 861                 left_true_state = decrement_state(left_true_state);
 862                 left_false_state = decrement_state(left_false_state);
 863         }
 864         if (right_postop == SPECIAL_INCREMENT) {
 865                 right_true_state = increment_state(right_true_state);
 866                 right_false_state = increment_state(right_false_state);
 867         }
 868         if (right_postop == SPECIAL_DECREMENT) {
 869                 right_true_state = decrement_state(right_true_state);
 870                 right_false_state = decrement_state(right_false_state);
 871         }
 872
 873         set_extra_expr_true_false(left, left_true_state, left_false_state);
 874         set_extra_expr_true_false(right, right_true_state, right_false_state);
 875 }
 876
 877 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 878 void __extra_match_condition(struct expression *expr)
 879 {
 880         struct symbol *sym;
 881         char *name;
 882         struct smatch_state *pre_state;
 883         struct smatch_state *true_state;
 884         struct smatch_state *false_state;
 885
 886         expr = strip_expr(expr);
 887         switch (expr->type) {
 888         case EXPR_CALL:
 889                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 890                 return;
 891         case EXPR_PREOP:
 892         case EXPR_SYMBOL:
 893         case EXPR_DEREF: {
 894                 sval_t zero;
 895
 896                 zero = sval_blank(expr);
 897                 zero.value = 0;
 898
 899                 name = get_variable_from_expr(expr, &sym);
 900                 if (!name)
 901                         return;
 902                 pre_state = get_state(my_id, name, sym);
 903                 true_state = add_filter(pre_state, zero);
 904                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 905                         false_state = alloc_estate(zero);
 906                 else
 907                         false_state = alloc_estate_empty();
 908                 set_extra_true_false(name, sym, true_state, false_state);
 909                 free_string(name);
 910                 return;
 911         }
 912         case EXPR_COMPARE:
 913                 match_comparison(expr);
 914                 return;
 915         case EXPR_ASSIGNMENT:
 916                 __extra_match_condition(expr->left);
 917                 return;
 918         }
 919 }
 920
 921 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 922 int implied_not_equal(struct expression *expr, long long val)
 923 {
 924         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 925 }
 926
 927 int is_whole_range(struct smatch_state *state)
 928 {
 929         return is_whole_range_rl(estate_ranges(state));
 930 }
 931
 932 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 933 {
 934         if (is_whole_range(state))
 935                 return;
 936         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 937 }
 938
 939 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
 940 {
 941         struct expression *arg;
 942         struct symbol *type;
 943         struct range_list *rl;
 944         char member_name[256];
 945         char *name;
 946         struct symbol *sym;
 947
 948         while (expr->type == EXPR_ASSIGNMENT)
 949                 expr = strip_expr(expr->right);
 950         if (expr->type != EXPR_CALL)
 951                 return;
 952         arg = get_argument_from_call_expr(expr->args, param);
 953         arg = strip_expr(arg);
 954         if (!arg)
 955                 return;
 956
 957         if (strcmp(key, "*$$") == 0) {
 958                 struct symbol *sym;
 959                 char buf[256];
 960                 char *name;
 961
 962                 if (arg->type == EXPR_PREOP && arg->op == '&') {
 963                         arg = strip_expr(arg->unop);
 964                         name = get_variable_from_expr(arg, &sym);
 965                 } else {
 966                         char *tmp = get_variable_from_expr(arg, &sym);
 967
 968                         if (!tmp)
 969                                 return;
 970                         snprintf(buf, sizeof(buf), "*%s", tmp);
 971                         name = alloc_string(buf);
 972                         free_string(tmp);
 973                 }
 974                 if (!name || !sym) {
 975                         free_string(name);
 976                         return;
 977                 }
 978                 type = get_type(arg);
 979                 parse_value_ranges_type(type, value, &rl);
 980                 set_extra_mod(name, sym, alloc_estate_range_list(rl));
 981                 free_string(name);
 982                 return;
 983         }
 984
 985         if (arg->type == EXPR_PREOP && arg->op == '&') {
 986                 arg = strip_expr(arg->unop);
 987                 name = get_variable_from_expr(arg, &sym);
 988                 if (!name || !sym)
 989                         goto free;
 990                 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
 991         } else {
 992                 name = get_variable_from_expr(arg, &sym);
 993                 if (!name || !sym)
 994                         goto free;
 995                 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
 996         }
 997         type = get_member_type_from_key(sym, key);
 998         if (!type)
 999                 goto free;
1000         parse_value_ranges_type(type, value, &rl);
1001         set_extra_mod(member_name, sym, alloc_estate_range_list(rl));
1002 free:
1003         free_string(name);
1004 }
1005
1006 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1007 {
1008         struct symbol *type;
1009         struct symbol *sym;
1010         char *name;
1011         char member_name[256];
1012         struct range_list *rl;
1013
1014         if (expr->type != EXPR_ASSIGNMENT)
1015                 return;
1016
1017         name = get_variable_from_expr(expr->left, &sym);
1018         if (!name || !sym)
1019                 goto free;
1020         snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1021         type = get_member_type_from_key(sym, key);
1022         if (!type)
1023                 return;
1024         parse_value_ranges_type(type, value, &rl);
1025         set_extra_mod(member_name, sym, alloc_estate_range_list(rl));
1026
1027 free:
1028         free_string(name);
1029 }
1030
1031 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1032 {
1033         if (is_whole_range(state))
1034                 return;
1035         sm_msg("info: return_value %d '%s' '%s' '%s' %s", return_id,
1036                return_ranges, printed_name, state->name, global_static());
1037 }
1038
1039 static struct state_list *start_states;
1040 static void save_start_states(struct statement *stmt)
1041 {
1042         if (!start_states)
1043                 start_states = get_all_states(SMATCH_EXTRA);
1044 }
1045
1046 static struct state_list *get_param_changed_list(struct state_list *source)
1047 {
1048         struct state_list *slist = NULL;
1049         struct state_list *cur;
1050         struct sm_state *old, *new;
1051
1052         cur = get_all_states_slist(SMATCH_EXTRA, source);
1053         FOR_EACH_PTR(cur, new) {
1054                 old = get_sm_state_slist(start_states, new->owner, new->name, new->sym);
1055                 if (old && estates_equiv(old->state, new->state))
1056                         continue;
1057                 add_ptr_list(&slist, new);
1058         } END_FOR_EACH_PTR(new);
1059
1060         return slist;
1061 }
1062
1063 static void print_return_value_param(int return_id, char *return_ranges, struct expression *expr, struct state_list *slist)
1064 {
1065         struct state_list *my_slist;
1066         struct sm_state *sm;
1067         char *param_name;
1068         int name_len;
1069         int param;
1070
1071         my_slist = get_param_changed_list(slist);
1072
1073         FOR_EACH_PTR(my_slist, sm) {
1074                 if (!estate_ranges(sm->state))
1075                         continue;
1076
1077                 param = get_param_num_from_sym(sm->sym);
1078                 if (param < 0)
1079                         continue;
1080
1081                 if (!sm->sym->ident)
1082                         continue;
1083                 param_name = sm->sym->ident->name;
1084                 name_len = strlen(param_name);
1085
1086                 if (strcmp(sm->name, param_name) == 0)
1087                         continue;
1088                 if (sm->name[name_len] == '-' &&
1089                     strncmp(sm->name, param_name, name_len) == 0) {
1090                         sm_msg("info: return_value_param %d %d '%s' '$$%s' '%s' %s",
1091                                return_id, param, return_ranges,
1092                                sm->name + name_len, sm->state->name, global_static());
1093                 } else if (sm->name[0] == '*' &&
1094                            strcmp(sm->name + 1, param_name) == 0) {
1095                         sm_msg("info: return_value_param %d %d '%s' '*$$' '%s' %s",
1096                                return_id, param, return_ranges,
1097                                sm->state->name, global_static());
1098                 }
1099         } END_FOR_EACH_PTR(sm);
1100 }
1101
1102 static void match_end_func(void)
1103 {
1104         free_slist(&start_states);
1105 }
1106
1107 static void match_call_info(struct expression *expr)
1108 {
1109         struct range_list *rl = NULL;
1110         struct expression *arg;
1111         struct symbol *type;
1112         char *name;
1113         int i = 0;
1114
1115         name = get_fnptr_name(expr->fn);
1116         if (!name)
1117                 return;
1118
1119         FOR_EACH_PTR(expr->args, arg) {
1120                 type = get_arg_type(expr->fn, i);
1121
1122                 if (get_implied_range_list(arg, &rl))
1123                         rl = cast_rl(type, rl);
1124                 else
1125                         rl = whole_range_list(type);
1126
1127                 sm_msg("info: passes param_value '%s' %d '$$' %s %s",
1128                        name, i, show_ranges(rl),
1129                        is_static(expr->fn) ? "static" : "global");
1130                 i++;
1131         } END_FOR_EACH_PTR(arg);
1132
1133         free_string(name);
1134 }
1135
1136 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1137 {
1138         struct range_list *rl = NULL;
1139         struct smatch_state *state;
1140         struct symbol *type;
1141         char fullname[256];
1142
1143         if (strncmp(key, "$$", 2))
1144                 return;
1145
1146         snprintf(fullname, 256, "%s%s", name, key + 2);
1147         type = get_member_type_from_key(sym, key);
1148         parse_value_ranges_type(type, value, &rl);
1149         state = alloc_estate_range_list(rl);
1150         set_state(SMATCH_EXTRA, fullname, sym, state);
1151 }
1152
1153 void register_smatch_extra(int id)
1154 {
1155         my_id = id;
1156
1157         add_merge_hook(my_id, &merge_estates);
1158         add_unmatched_state_hook(my_id, &unmatched_state);
1159         add_hook(&match_function_def, FUNC_DEF_HOOK);
1160         add_hook(&match_declarations, DECLARATION_HOOK);
1161         add_definition_db_callback(set_param_value, PARAM_VALUE);
1162         add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1163         add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1164 }
1165
1166 void register_smatch_extra_late(int id)
1167 {
1168         add_hook(&match_dereferences, DEREF_HOOK);
1169         add_hook(&match_pointer_as_array, OP_HOOK);
1170         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1171         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1172         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1173         add_hook(&match_assign, ASSIGNMENT_HOOK);
1174         add_hook(&unop_expr, OP_HOOK);
1175         add_hook(&asm_expr, ASM_HOOK);
1176
1177         if (option_info) {
1178                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1179                 add_member_info_callback(my_id, struct_member_callback);
1180                 add_returned_member_callback(my_id, returned_member_callback);
1181
1182                 add_hook(&save_start_states, STMT_HOOK);
1183                 add_returned_state_callback(&print_return_value_param);
1184                 add_hook(&match_end_func, END_FUNC_HOOK);
1185         }
1186 }