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_list(struct smatch_state *orig,
 131                                  struct range_list_sval *rl)
 132 {
 133         struct range_list_sval *res;
 134         struct data_range_sval *tmp;
 135
 136         if (!orig)
 137                 orig = extra_undefined();
 138         res = estate_ranges_sval(orig);
 139
 140         FOR_EACH_PTR(rl, tmp) {
 141                 res = remove_range_sval(res, tmp->min, tmp->max);
 142         } END_FOR_EACH_PTR(tmp);
 143
 144         return alloc_estate_range_list_sval(res);
 145 }
 146
 147 struct smatch_state *filter_range(struct smatch_state *orig,
 148                                  sval_t filter_min, sval_t filter_max)
 149 {
 150         struct range_list_sval *rl;
 151
 152         if (!orig)
 153                 orig = extra_undefined();
 154
 155         rl = remove_range_sval(estate_ranges_sval(orig), filter_min, filter_max);
 156         return alloc_estate_range_list_sval(rl);
 157 }
 158
 159 struct smatch_state *add_filter(struct smatch_state *orig, sval_t sval)
 160 {
 161         return filter_range(orig, sval, sval);
 162 }
 163
 164 static struct smatch_state *merge_func(struct smatch_state *s1, struct smatch_state *s2)
 165 {
 166         struct smatch_state *tmp;
 167         struct range_list_sval *value_ranges;
 168         struct related_list *rlist;
 169
 170         if (estates_equiv(s1, s2))
 171                 return s1;
 172
 173         value_ranges = range_list_union_sval(estate_ranges_sval(s1), estate_ranges_sval(s2));
 174         tmp = alloc_estate_range_list_sval(value_ranges);
 175         rlist = get_shared_relations(estate_related(s1), estate_related(s2));
 176         set_related(&tmp, rlist);
 177
 178         return tmp;
 179 }
 180
 181 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
 182 {
 183         struct expression *iter_var;
 184         struct expression *condition;
 185         struct sm_state *sm;
 186         sval_t start;
 187
 188         condition = strip_expr(loop->iterator_pre_condition);
 189         if (!condition)
 190                 return NULL;
 191         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 192                 return NULL;
 193         if (condition->op != SPECIAL_DECREMENT)
 194                 return NULL;
 195
 196         iter_var = condition->unop;
 197         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 198         if (!sm)
 199                 return NULL;
 200         if (sval_cmp_val(estate_min_sval(sm->state), 0) < 0)
 201                 return NULL;
 202         start = estate_max_sval(sm->state);
 203         if  (sval_cmp_val(start, 0) <= 0)
 204                 return NULL;
 205         if (!sval_is_max(start))
 206                 start.value--;
 207
 208         if (condition->type == EXPR_PREOP)
 209                 set_extra_expr_mod(iter_var, alloc_estate_range_sval(ll_to_sval(1), start));
 210         if (condition->type == EXPR_POSTOP)
 211                 set_extra_expr_mod(iter_var, alloc_estate_range_sval(ll_to_sval(0), start));
 212         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 213 }
 214
 215 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
 216                                                 struct expression *condition)
 217 {
 218         struct expression *iter_var;
 219         struct sm_state *sm;
 220         sval_t start, end;
 221
 222         iter_var = iter_expr->unop;
 223         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 224         if (!sm)
 225                 return NULL;
 226         if (!estate_get_single_value_sval(sm->state, &start))
 227                 return NULL;
 228         if (!get_implied_value_sval(condition->right, &end))
 229                 end = sval_type_max(get_type(iter_var));
 230
 231         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 232                 return NULL;
 233
 234         switch (condition->op) {
 235         case SPECIAL_NOTEQUAL:
 236         case '<':
 237                 if (!sval_is_max(end))
 238                         end.value--;
 239                 break;
 240         case SPECIAL_LTE:
 241                 break;
 242         default:
 243                 return NULL;
 244         }
 245         if (sval_cmp(end, start) < 0)
 246                 return NULL;
 247         set_extra_expr_mod(iter_var, alloc_estate_range_sval(start, end));
 248         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 249 }
 250
 251 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
 252                                                 struct expression *condition)
 253 {
 254         struct expression *iter_var;
 255         struct sm_state *sm;
 256         sval_t start, end;
 257
 258         iter_var = iter_expr->unop;
 259         sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
 260         if (!sm)
 261                 return NULL;
 262         if (!estate_get_single_value_sval(sm->state, &start))
 263                 return NULL;
 264         if (!get_implied_value_sval(condition->right, &end))
 265                 end = sval_type_min(get_type(iter_var));
 266         if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
 267                 return NULL;
 268
 269         switch (condition->op) {
 270         case SPECIAL_NOTEQUAL:
 271         case '>':
 272                 if (!sval_is_min(end) && !sval_is_max(end))
 273                         end.value++;
 274                 break;
 275         case SPECIAL_GTE:
 276                 break;
 277         default:
 278                 return NULL;
 279         }
 280         if (sval_cmp(end, start) > 0)
 281                 return NULL;
 282         set_extra_expr_mod(iter_var, alloc_estate_range_sval(end, start));
 283         return get_sm_state_expr(SMATCH_EXTRA, iter_var);
 284 }
 285
 286 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
 287 {
 288         struct expression *iter_expr;
 289         struct expression *condition;
 290
 291         if (!loop->iterator_post_statement)
 292                 return NULL;
 293         if (loop->iterator_post_statement->type != STMT_EXPRESSION)
 294                 return NULL;
 295         iter_expr = loop->iterator_post_statement->expression;
 296         if (!loop->iterator_pre_condition)
 297                 return NULL;
 298         if (loop->iterator_pre_condition->type != EXPR_COMPARE)
 299                 return NULL;
 300         condition = loop->iterator_pre_condition;
 301
 302         if (iter_expr->op == SPECIAL_INCREMENT)
 303                 return handle_canonical_for_inc(iter_expr, condition);
 304         if (iter_expr->op == SPECIAL_DECREMENT)
 305                 return handle_canonical_for_dec(iter_expr, condition);
 306         return NULL;
 307 }
 308
 309 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
 310 {
 311         struct sm_state *ret;
 312
 313         __push_fake_cur_slist();
 314         if (!loop->iterator_post_statement)
 315                 ret = handle_canonical_while_count_down(loop);
 316         else
 317                 ret = handle_canonical_for_loops(loop);
 318         *slist = __pop_fake_cur_slist();
 319         return ret;
 320 }
 321
 322 int __iterator_unchanged(struct sm_state *sm)
 323 {
 324         if (!sm)
 325                 return 0;
 326         if (get_sm_state(my_id, sm->name, sm->sym) == sm)
 327                 return 1;
 328         return 0;
 329 }
 330
 331 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
 332 {
 333         sval_t after_value;
 334
 335         /* paranoid checking.  prolly not needed */
 336         condition = strip_expr(condition);
 337         if (!condition)
 338                 return;
 339         if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
 340                 return;
 341         if (condition->op != SPECIAL_DECREMENT)
 342                 return;
 343         after_value = estate_min_sval(sm->state);
 344         after_value.value--;
 345         set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
 346 }
 347
 348 void __extra_pre_loop_hook_after(struct sm_state *sm,
 349                                 struct statement *iterator,
 350                                 struct expression *condition)
 351 {
 352         struct expression *iter_expr;
 353         char *name;
 354         struct symbol *sym;
 355         sval_t value;
 356         int left = 0;
 357         struct smatch_state *state;
 358         sval_t min, max;
 359
 360         if (!iterator) {
 361                 while_count_down_after(sm, condition);
 362                 return;
 363         }
 364
 365         iter_expr = iterator->expression;
 366
 367         if (condition->type != EXPR_COMPARE)
 368                 return;
 369         if (!get_value_sval(condition->left, &value)) {
 370                 if (!get_value_sval(condition->right, &value))
 371                         return;
 372                 left = 1;
 373         }
 374         if (left)
 375                 name = get_variable_from_expr(condition->left, &sym);
 376         else
 377                 name = get_variable_from_expr(condition->right, &sym);
 378         if (!name || !sym)
 379                 goto free;
 380         if (sym != sm->sym || strcmp(name, sm->name))
 381                 goto free;
 382         state = get_state(my_id, name, sym);
 383         min = estate_min_sval(state);
 384         max = estate_max_sval(state);
 385         if (iter_expr->op == SPECIAL_INCREMENT &&
 386             !sval_is_min(min) && sval_is_max(max))
 387                 set_extra_mod(name, sym, alloc_estate_sval(min));
 388         else if (sval_is_min(min) && !sval_is_max(max))
 389                 set_extra_mod(name, sym, alloc_estate_sval(max));
 390
 391 free:
 392         free_string(name);
 393         return;
 394 }
 395
 396 static struct smatch_state *unmatched_state(struct sm_state *sm)
 397 {
 398         return extra_undefined();
 399 }
 400
 401 static void match_function_call(struct expression *expr)
 402 {
 403         struct expression *arg;
 404         struct expression *tmp;
 405
 406         FOR_EACH_PTR(expr->args, arg) {
 407                 tmp = strip_expr(arg);
 408                 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
 409                         remove_from_equiv_expr(tmp->unop);
 410                         set_state_expr(SMATCH_EXTRA, tmp->unop, extra_undefined());
 411                 }
 412         } END_FOR_EACH_PTR(arg);
 413 }
 414
 415 static void match_assign(struct expression *expr)
 416 {
 417         struct range_list_sval *rl = NULL;
 418         struct expression *left;
 419         struct expression *right;
 420         struct symbol *right_sym;
 421         char *right_name;
 422         struct symbol *sym;
 423         char *name;
 424         sval_t value;
 425         int known;
 426         sval_t right_min, right_max;
 427         sval_t tmp;
 428
 429         if (__is_condition_assign(expr))
 430                 return;
 431         left = strip_expr(expr->left);
 432         name = get_variable_from_expr(left, &sym);
 433         if (!name)
 434                 return;
 435         right = strip_parens(expr->right);
 436         while (right->type == EXPR_ASSIGNMENT && right->op == '=')
 437                 right = strip_parens(right->left);
 438
 439         if (expr->op == '=' && right->type == EXPR_CALL)
 440                 return;  /* these are handled in match_call_assign() */
 441
 442         right_name = get_variable_from_expr(right, &right_sym);
 443         if (expr->op == '=' && right_name && right_sym &&
 444             types_equiv(get_type(expr->left), get_type(expr->right))) {
 445                 set_equiv(left, right);
 446                 goto free;
 447         }
 448
 449         right_min = sval_type_min(get_type(expr->right));
 450         right_max = sval_type_max(get_type(expr->right));
 451
 452         known = get_implied_value_sval(right, &value);
 453         switch (expr->op) {
 454         case '=': {
 455                 if (get_implied_range_list_sval(right, &rl)) {
 456                         rl = cast_rl(rl, get_type(expr->left));
 457                         set_extra_mod(name, sym, alloc_estate_range_list_sval(rl));
 458                         goto free;
 459                 }
 460
 461                 break;
 462         }
 463         case SPECIAL_ADD_ASSIGN:
 464                 if (get_implied_min_sval(left, &tmp)) {
 465                         if (known)
 466                                 right_min = sval_binop(tmp, '+', value);
 467                         else
 468                                 right_min = tmp;
 469                 }
 470                 if (!inside_loop() && known && get_implied_max_sval(left, &tmp))
 471                         right_max = sval_binop(tmp, '+', value);
 472                 break;
 473         case SPECIAL_SUB_ASSIGN:
 474                 if (get_implied_max_sval(left, &tmp)) {
 475                         if (known)
 476                                 right_max = sval_binop(tmp, '-', value);
 477                         else
 478                                 right_max = tmp;
 479                 }
 480                 if (!inside_loop() && known && get_implied_min_sval(left, &tmp))
 481                         right_min = sval_binop(tmp, '-', value);
 482                 break;
 483         }
 484         rl = cast_rl(alloc_range_list_sval(right_min, right_max), get_type(expr->left));
 485         set_extra_mod(name, sym, alloc_estate_range_list_sval(rl));
 486 free:
 487         free_string(right_name);
 488         free_string(name);
 489 }
 490
 491 static void reset_struct_members(struct sm_state *sm)
 492 {
 493         set_extra_mod(sm->name, sm->sym, extra_undefined());
 494 }
 495
 496 static struct smatch_state *increment_state(struct smatch_state *state)
 497 {
 498         sval_t min = estate_min_sval(state);
 499         sval_t max = estate_max_sval(state);
 500
 501         if (inside_loop())
 502                 max = sval_type_max(max.type);
 503
 504         if (!sval_is_min(min))
 505                 min.value++;
 506         if (!sval_is_max(max))
 507                 max.value++;
 508         return alloc_estate_range_sval(min, max);
 509 }
 510
 511 static struct smatch_state *decrement_state(struct smatch_state *state)
 512 {
 513         sval_t min = estate_min_sval(state);
 514         sval_t max = estate_max_sval(state);
 515
 516         if (inside_loop())
 517                 min = sval_type_min(min.type);
 518
 519         if (!sval_is_min(min))
 520                 min.value--;
 521         if (!sval_is_max(max))
 522                 max.value--;
 523         return alloc_estate_range_sval(min, max);
 524 }
 525
 526 static void unop_expr(struct expression *expr)
 527 {
 528         struct smatch_state *state;
 529
 530         if (expr->smatch_flags & Handled)
 531                 return;
 532
 533         switch (expr->op) {
 534         case SPECIAL_INCREMENT:
 535                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 536                 state = increment_state(state);
 537                 set_extra_expr_mod(expr->unop, state);
 538                 break;
 539         case SPECIAL_DECREMENT:
 540                 state = get_state_expr(SMATCH_EXTRA, expr->unop);
 541                 state = decrement_state(state);
 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());
 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());
 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_sval(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());
 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_sval(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_sval(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_sval *left_orig;
 672         struct range_list_sval *left_true;
 673         struct range_list_sval *left_false;
 674         struct range_list_sval *right_orig;
 675         struct range_list_sval *right_true;
 676         struct range_list_sval *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;
 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
 696         if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
 697                 if (right->type == EXPR_POSTOP) {
 698                         right->smatch_flags |= Handled;
 699                         right_postop = right->op;
 700                 }
 701                 right = strip_expr(right->unop);
 702         }
 703
 704         type = get_type(expr);
 705         if (!type) {
 706                 sm_msg("debug: failed to get type for '%s'", get_variable_from_expr_complex(expr, NULL));
 707                 type = &int_ctype;
 708         }
 709         min = sval_type_min(type);
 710         max = sval_type_max(type);
 711         if (get_implied_range_list_sval(left, &left_orig))
 712                 left_orig = cast_rl(left_orig, type);
 713         else
 714                 left_orig = alloc_range_list_sval(min, max);
 715
 716         if (get_implied_range_list_sval(right, &right_orig))
 717                 right_orig = cast_rl(right_orig, type);
 718         else
 719                 right_orig = alloc_range_list_sval(min, max);
 720
 721         left_true = clone_range_list_sval(left_orig);
 722         left_false = clone_range_list_sval(left_orig);
 723         right_true = clone_range_list_sval(right_orig);
 724         right_false = clone_range_list_sval(right_orig);
 725
 726         switch (expr->op) {
 727         case '<':
 728         case SPECIAL_UNSIGNED_LT:
 729                 if (!sval_is_max(rl_max_sval(right_orig))) {
 730                         left_true = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 731                 }
 732                 if (!sval_is_min(rl_min_sval(right_orig))) {
 733                         left_false = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 734                 }
 735
 736                 if (!sval_is_min(rl_min_sval(left_orig)))
 737                         right_true = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 738                 if (!sval_is_max(rl_max_sval(left_orig)))
 739                         right_false = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 740                 break;
 741         case SPECIAL_UNSIGNED_LTE:
 742         case SPECIAL_LTE:
 743                 if (!sval_is_max(rl_max_sval(right_orig)))
 744                         left_true = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 745                 if (!sval_is_min(rl_min_sval(right_orig)))
 746                         left_false = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 747
 748                 if (!sval_is_min(rl_min_sval(left_orig)))
 749                         right_true = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 750                 if (!sval_is_max(rl_max_sval(left_orig)))
 751                         right_false = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 752                 break;
 753         case SPECIAL_EQUAL:
 754                 if (!sval_is_max(rl_max_sval(right_orig))) {
 755                         left_true = remove_range_sval(left_true, add_one(rl_max_sval(right_orig)), max);
 756                 }
 757                 if (!sval_is_min(rl_min_sval(right_orig))) {
 758                         left_true = remove_range_sval(left_true, min, sub_one(rl_min_sval(right_orig)));
 759                 }
 760                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 761                         left_false = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 762
 763                 if (!sval_is_max(rl_max_sval(left_orig)))
 764                         right_true = remove_range_sval(right_true, add_one(rl_max_sval(left_orig)), max);
 765                 if (!sval_is_min(rl_min_sval(left_orig)))
 766                         right_true = remove_range_sval(right_true, min, sub_one(rl_min_sval(left_orig)));
 767                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 768                         right_false = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 769                 break;
 770         case SPECIAL_UNSIGNED_GTE:
 771         case SPECIAL_GTE:
 772                 if (!sval_is_min(rl_min_sval(right_orig)))
 773                         left_true = remove_range_sval(left_orig, min, sub_one(rl_min_sval(right_orig)));
 774                 if (!sval_is_max(rl_max_sval(right_orig)))
 775                         left_false = remove_range_sval(left_orig, rl_max_sval(right_orig), max);
 776
 777                 if (!sval_is_max(rl_max_sval(left_orig)))
 778                         right_true = remove_range_sval(right_orig, add_one(rl_max_sval(left_orig)), max);
 779                 if (!sval_is_min(rl_min_sval(left_orig)))
 780                         right_false = remove_range_sval(right_orig, min, rl_min_sval(left_orig));
 781                 break;
 782         case '>':
 783         case SPECIAL_UNSIGNED_GT:
 784                 if (!sval_is_min(rl_min_sval(right_orig)))
 785                         left_true = remove_range_sval(left_orig, min, rl_min_sval(right_orig));
 786                 if (!sval_is_max(rl_max_sval(right_orig)))
 787                         left_false = remove_range_sval(left_orig, add_one(rl_max_sval(right_orig)), max);
 788
 789                 if (!sval_is_max(rl_max_sval(left_orig)))
 790                         right_true = remove_range_sval(right_orig, rl_max_sval(left_orig), max);
 791                 if (!sval_is_min(rl_min_sval(left_orig)))
 792                         right_false = remove_range_sval(right_orig, min, sub_one(rl_min_sval(left_orig)));
 793                 break;
 794         case SPECIAL_NOTEQUAL:
 795                 if (!sval_is_max(rl_max_sval(right_orig)))
 796                         left_false = remove_range_sval(left_false, add_one(rl_max_sval(right_orig)), max);
 797                 if (!sval_is_min(rl_min_sval(right_orig)))
 798                         left_false = remove_range_sval(left_false, min, sub_one(rl_min_sval(right_orig)));
 799                 if (sval_cmp(rl_min_sval(right_orig), rl_max_sval(right_orig)) == 0)
 800                         left_true = remove_range_sval(left_orig, rl_min_sval(right_orig), rl_min_sval(right_orig));
 801
 802                 if (!sval_is_max(rl_max_sval(left_orig)))
 803                         right_false = remove_range_sval(right_false, add_one(rl_max_sval(left_orig)), max);
 804                 if (!sval_is_min(rl_min_sval(left_orig)))
 805                         right_false = remove_range_sval(right_false, min, sub_one(rl_min_sval(left_orig)));
 806                 if (sval_cmp(rl_min_sval(left_orig), rl_max_sval(left_orig)) == 0)
 807                         right_true = remove_range_sval(right_orig, rl_min_sval(left_orig), rl_min_sval(left_orig));
 808                 break;
 809         default:
 810                 return;
 811         }
 812
 813         left_true_state = alloc_estate_range_list_sval(cast_rl(left_true, get_type(left)));
 814         left_false_state = alloc_estate_range_list_sval(cast_rl(left_false, get_type(left)));
 815         right_true_state = alloc_estate_range_list_sval(cast_rl(right_true, get_type(right)));
 816         right_false_state = alloc_estate_range_list_sval(cast_rl(right_false, get_type(right)));
 817
 818         if (left_postop == SPECIAL_INCREMENT) {
 819                 left_true_state = increment_state(left_true_state);
 820                 left_false_state = increment_state(left_false_state);
 821         }
 822         if (left_postop == SPECIAL_DECREMENT) {
 823                 left_true_state = decrement_state(left_true_state);
 824                 left_false_state = decrement_state(left_false_state);
 825         }
 826         if (right_postop == SPECIAL_INCREMENT) {
 827                 right_true_state = increment_state(right_true_state);
 828                 right_false_state = increment_state(right_false_state);
 829         }
 830         if (right_postop == SPECIAL_DECREMENT) {
 831                 right_true_state = decrement_state(right_true_state);
 832                 right_false_state = decrement_state(right_false_state);
 833         }
 834
 835         set_extra_expr_true_false(left, left_true_state, left_false_state);
 836         set_extra_expr_true_false(right, right_true_state, right_false_state);
 837 }
 838
 839 /* this is actually hooked from smatch_implied.c...  it's hacky, yes */
 840 void __extra_match_condition(struct expression *expr)
 841 {
 842         struct symbol *sym;
 843         char *name;
 844         struct smatch_state *pre_state;
 845         struct smatch_state *true_state;
 846         struct smatch_state *false_state;
 847
 848         expr = strip_expr(expr);
 849         switch (expr->type) {
 850         case EXPR_CALL:
 851                 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
 852                 return;
 853         case EXPR_PREOP:
 854         case EXPR_SYMBOL:
 855         case EXPR_DEREF:
 856                 name = get_variable_from_expr(expr, &sym);
 857                 if (!name)
 858                         return;
 859                 pre_state = get_state(my_id, name, sym);
 860                 true_state = add_filter(pre_state, ll_to_sval(0));
 861                 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
 862                         false_state = alloc_estate_sval(ll_to_sval(0));
 863                 else
 864                         false_state = alloc_estate_empty();
 865                 set_extra_true_false(name, sym, true_state, false_state);
 866                 free_string(name);
 867                 return;
 868         case EXPR_COMPARE:
 869                 match_comparison(expr);
 870                 return;
 871         case EXPR_ASSIGNMENT:
 872                 __extra_match_condition(expr->left);
 873                 return;
 874         }
 875 }
 876
 877 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
 878 int implied_not_equal(struct expression *expr, long long val)
 879 {
 880         return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
 881 }
 882
 883 int get_implied_range_list_sval(struct expression *expr, struct range_list_sval **rl)
 884 {
 885         sval_t sval;
 886         struct smatch_state *state;
 887         sval_t min, max;
 888
 889         *rl = NULL;
 890
 891         expr = strip_parens(expr);
 892         if (!expr)
 893                 return 0;
 894
 895         state = get_state_expr(my_id, expr);
 896         if (state) {
 897                 *rl = clone_range_list_sval(estate_ranges_sval(state));
 898                 goto out;
 899         }
 900
 901         if (expr->type == EXPR_CALL) {
 902                 if (get_implied_return_sval(expr, rl))
 903                         goto out;
 904                 *rl = db_return_vals(expr);
 905                 goto out;
 906         }
 907
 908         if (get_implied_value_sval(expr, &sval)) {
 909                 add_range_sval(rl, sval, sval);
 910                 goto out;
 911         }
 912
 913         if (expr->type == EXPR_BINOP && expr->op == '%') {
 914                 if (!get_implied_value_sval(expr->right, &sval))
 915                         return 0;
 916                 add_range_sval(rl, ll_to_sval(0), ll_to_sval(sval.value - 1));
 917                 goto out;
 918         }
 919
 920         if (!get_implied_min_sval(expr, &min))
 921                 return 0;
 922         if (!get_implied_max_sval(expr, &max))
 923                 return 0;
 924
 925         *rl = alloc_range_list_sval(min, max);
 926
 927 out:
 928         if (is_whole_range_rl_sval(*rl))
 929                 return 0;
 930         return 1;
 931 }
 932
 933 int is_whole_range(struct smatch_state *state)
 934 {
 935         return is_whole_range_rl_sval(estate_ranges_sval(state));
 936 }
 937
 938 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
 939 {
 940         if (is_whole_range(state))
 941                 return;
 942         sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
 943 }
 944
 945 static void match_call_info(struct expression *expr)
 946 {
 947         struct range_list_sval *rl = NULL;
 948         struct expression *arg;
 949         char *name;
 950         int i = 0;
 951
 952         name = get_fnptr_name(expr->fn);
 953         if (!name)
 954                 return;
 955
 956         FOR_EACH_PTR(expr->args, arg) {
 957                 if (get_implied_range_list_sval(arg, &rl) && !is_whole_range_rl_sval(rl)) {
 958                         sm_msg("info: passes param_value '%s' %d '$$' %s %s",
 959                                name, i, show_ranges_sval(rl),
 960                                is_static(expr->fn) ? "static" : "global");
 961                 }
 962                 i++;
 963         } END_FOR_EACH_PTR(arg);
 964
 965         free_string(name);
 966 }
 967
 968 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
 969 {
 970         struct range_list_sval *rl = NULL;
 971         struct smatch_state *state;
 972         char fullname[256];
 973
 974         if (strncmp(key, "$$", 2))
 975                 return;
 976
 977         snprintf(fullname, 256, "%s%s", name, key + 2);
 978         get_value_ranges_sval(value, &rl);
 979         state = alloc_estate_range_list_sval(rl);
 980         set_state(SMATCH_EXTRA, fullname, sym, state);
 981 }
 982
 983 static void match_call_assign(struct expression *expr)
 984 {
 985         if (expr->op != '=')
 986                 return;
 987
 988         /* if we have a db set up this gets set in smatch_function_hooks.c */
 989         if (option_no_db)
 990                 set_extra_expr_mod(expr->left, extra_undefined());
 991 }
 992
 993 void register_smatch_extra(int id)
 994 {
 995         my_id = id;
 996
 997         alloc_estate_undefined();
 998         add_merge_hook(my_id, &merge_func);
 999         add_unmatched_state_hook(my_id, &unmatched_state);
1000         add_hook(&unop_expr, OP_HOOK);
1001         add_hook(&asm_expr, ASM_HOOK);
1002         add_hook(&match_function_def, FUNC_DEF_HOOK);
1003         add_hook(&match_declarations, DECLARATION_HOOK);
1004         if (option_info) {
1005                 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1006                 add_member_info_callback(my_id, struct_member_callback);
1007         }
1008         add_definition_db_callback(set_param_value, PARAM_VALUE);
1009 }
1010
1011 void register_smatch_extra_late(int id)
1012 {
1013         add_hook(&match_dereferences, DEREF_HOOK);
1014         add_hook(&match_pointer_as_array, OP_HOOK);
1015         add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1016         add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1017         add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1018         add_hook(&match_assign, ASSIGNMENT_HOOK);
1019         add_hook(&match_call_assign, CALL_ASSIGNMENT_HOOK);
1020 }