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type: make sval_type_max() default to "long long"
[smatch.git] / smatch_extra.c
blobccb62182fd8ae23990199c0805c3b0a307102aab
1 /*
2 * Copyright (C) 2008 Dan Carpenter.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 */
17
18 /*
19 * smatch_extra.c is supposed to track the value of every variable.
20 *
21 */
22
23 #include <stdlib.h>
24 #include <errno.h>
25 #ifndef __USE_ISOC99
26 #define __USE_ISOC99
27 #endif
28 #include <limits.h>
29 #include "parse.h"
30 #include "smatch.h"
31 #include "smatch_slist.h"
32 #include "smatch_extra.h"
33
34 static int my_id;
35
36 struct string_list *__ignored_macros = NULL;
37 static int in_warn_on_macro(void)
38 {
39 struct statement *stmt;
40 char *tmp;
41 char *macro;
42
43 stmt = get_current_statement();
44 if (!stmt)
45 return 0;
46 macro = get_macro_name(stmt->pos);
47 if (!macro)
48 return 0;
49
50 FOR_EACH_PTR(__ignored_macros, tmp) {
51 if (!strcmp(tmp, macro))
52 return 1;
53 } END_FOR_EACH_PTR(tmp);
54 return 0;
55 }
56
57 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
58 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
59 static struct void_fn_list *extra_mod_hooks;
60 void add_extra_mod_hook(mod_hook *fn)
61 {
62 mod_hook **p = malloc(sizeof(mod_hook *));
63 *p = fn;
64 add_ptr_list(&extra_mod_hooks, p);
65 }
66
67 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
68 {
69 mod_hook **fn;
70
71 FOR_EACH_PTR(extra_mod_hooks, fn) {
72 (*fn)(name, sym, state);
73 } END_FOR_EACH_PTR(fn);
74 }
75
76 struct sm_state *set_extra_mod_helper(const char *name, struct symbol *sym, struct smatch_state *state)
77 {
78 remove_from_equiv(name, sym);
79 call_extra_mod_hooks(name, sym, state);
80 if (__in_fake_assign && estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
81 return NULL;
82 return set_state(SMATCH_EXTRA, name, sym, state);
83 }
84
85 static char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
86 {
87 struct expression *assigned;
88 char *orig_name = NULL;
89 char buf[256];
90 char *ret = NULL;
91 int skip;
92
93 *new_sym = NULL;
94
95 if (!sym->ident)
96 return NULL;
97
98 skip = strlen(sym->ident->name);
99 if (name[skip] != '-' || name[skip + 1] != '>')
100 return NULL;
101 skip += 2;
102
103 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
104 if (!assigned)
105 return NULL;
106 if (assigned->type == EXPR_PREOP || assigned->op == '&') {
107
108 orig_name = expr_to_var_sym(assigned, new_sym);
109 if (!orig_name || !*new_sym)
110 goto free;
111
112 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + skip);
113 ret = alloc_string(buf);
114 free_string(orig_name);
115 return ret;
116 }
117
118 if (assigned->type != EXPR_DEREF)
119 goto free;
120
121 orig_name = expr_to_var_sym(assigned, new_sym);
122 if (!orig_name || !*new_sym)
123 goto free;
124
125 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + skip);
126 ret = alloc_string(buf);
127 free_string(orig_name);
128 return ret;
129
130 free:
131 free_string(orig_name);
132 return NULL;
133 }
134
135 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
136 {
137 char *new_name;
138 struct symbol *new_sym;
139 struct sm_state *sm;
140
141 if (in_warn_on_macro())
142 return NULL;
143 sm = set_extra_mod_helper(name, sym, state);
144 new_name = get_other_name_sym(name, sym, &new_sym);
145 if (new_name && new_sym)
146 set_extra_mod_helper(new_name, new_sym, state);
147 free_string(new_name);
148 return sm;
149 }
150
151 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
152 {
153 struct symbol *sym;
154 char *name;
155 struct sm_state *ret = NULL;
156
157 expr = strip_expr(expr);
158 name = expr_to_var_sym(expr, &sym);
159 if (!name || !sym)
160 goto free;
161 ret = set_extra_mod(name, sym, state);
162 free:
163 free_string(name);
164 return ret;
165 }
166
167 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
168 {
169 char *new_name;
170 struct symbol *new_sym;
171 struct relation *rel;
172 struct smatch_state *orig_state;
173
174 orig_state = get_state(SMATCH_EXTRA, name, sym);
175
176 new_name = get_other_name_sym(name, sym, &new_sym);
177 if (new_name && new_sym)
178 set_state(SMATCH_EXTRA, new_name, new_sym, state);
179 free_string(new_name);
180
181 if (!estate_related(orig_state)) {
182 set_state(SMATCH_EXTRA, name, sym, state);
183 return;
184 }
185
186 set_related(state, estate_related(orig_state));
187 FOR_EACH_PTR(estate_related(orig_state), rel) {
188 if (option_debug_related)
189 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
190 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
191 } END_FOR_EACH_PTR(rel);
192 }
193
194 /*
195 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
196 */
197 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
198 {
199 char *name;
200 struct symbol *sym;
201
202 name = expr_to_var_sym(expr, &sym);
203 if (!name || !sym)
204 goto free;
205 set_extra_nomod(name, sym, state);
206 free:
207 free_string(name);
208
209 }
210
211 static void set_extra_true_false(const char *name, struct symbol *sym,
212 struct smatch_state *true_state,
213 struct smatch_state *false_state)
214 {
215 char *new_name;
216 struct symbol *new_sym;
217 struct relation *rel;
218 struct smatch_state *orig_state;
219
220 if (in_warn_on_macro())
221 return;
222
223 new_name = get_other_name_sym(name, sym, &new_sym);
224 if (new_name && new_sym)
225 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
226 free_string(new_name);
227
228 orig_state = get_state(SMATCH_EXTRA, name, sym);
229
230 if (!estate_related(orig_state)) {
231 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
232 return;
233 }
234
235 if (true_state)
236 set_related(true_state, estate_related(orig_state));
237 if (false_state)
238 set_related(false_state, estate_related(orig_state));
239
240 FOR_EACH_PTR(estate_related(orig_state), rel) {
241 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
242 true_state, false_state);
243 } END_FOR_EACH_PTR(rel);
244 }
245
246 static void set_extra_expr_true_false(struct expression *expr,
247 struct smatch_state *true_state,
248 struct smatch_state *false_state)
249 {
250 char *name;
251 struct symbol *sym;
252
253 expr = strip_expr(expr);
254 name = expr_to_var_sym(expr, &sym);
255 if (!name || !sym)
256 goto free;
257 set_extra_true_false(name, sym, true_state, false_state);
258 free:
259 free_string(name);
260 }
261
262 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
263 {
264 struct expression *iter_var;
265 struct expression *condition;
266 struct sm_state *sm;
267 struct smatch_state *estate;
268 sval_t start;
269
270 condition = strip_expr(loop->iterator_pre_condition);
271 if (!condition)
272 return NULL;
273 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
274 return NULL;
275 if (condition->op != SPECIAL_DECREMENT)
276 return NULL;
277
278 iter_var = condition->unop;
279 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
280 if (!sm)
281 return NULL;
282 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
283 return NULL;
284 start = estate_max(sm->state);
285 if (sval_cmp_val(start, 0) <= 0)
286 return NULL;
287 if (!sval_is_max(start))
288 start.value--;
289
290 if (condition->type == EXPR_PREOP) {
291 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
292 if (estate_has_hard_max(sm->state))
293 estate_set_hard_max(estate);
294 estate_copy_fuzzy_max(estate, sm->state);
295 set_extra_expr_mod(iter_var, estate);
296 }
297 if (condition->type == EXPR_POSTOP) {
298 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
299 if (estate_has_hard_max(sm->state))
300 estate_set_hard_max(estate);
301 estate_copy_fuzzy_max(estate, sm->state);
302 set_extra_expr_mod(iter_var, estate);
303 }
304 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
305 }
306
307 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
308 struct expression *condition)
309 {
310 struct expression *iter_var;
311 struct sm_state *sm;
312 struct smatch_state *estate;
313 sval_t start, end, max;
314
315 iter_var = iter_expr->unop;
316 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
317 if (!sm)
318 return NULL;
319 if (!estate_get_single_value(sm->state, &start))
320 return NULL;
321 if (get_implied_max(condition->right, &end))
322 end = sval_cast(get_type(iter_var), end);
323 else
324 end = sval_type_max(get_type(iter_var));
325
326 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
327 return NULL;
328
329 switch (condition->op) {
330 case SPECIAL_UNSIGNED_LT:
331 case SPECIAL_NOTEQUAL:
332 case '<':
333 if (!sval_is_min(end))
334 end.value--;
335 break;
336 case SPECIAL_UNSIGNED_LTE:
337 case SPECIAL_LTE:
338 break;
339 default:
340 return NULL;
341 }
342 if (sval_cmp(end, start) < 0)
343 return NULL;
344 estate = alloc_estate_range(start, end);
345 if (get_hard_max(condition->right, &max)) {
346 estate_set_hard_max(estate);
347 if (condition->op == '<' ||
348 condition->op == SPECIAL_UNSIGNED_LT ||
349 condition->op == SPECIAL_NOTEQUAL)
350 max.value--;
351 estate_set_fuzzy_max(estate, max);
352 }
353 set_extra_expr_mod(iter_var, estate);
354 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
355 }
356
357 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
358 struct expression *condition)
359 {
360 struct expression *iter_var;
361 struct sm_state *sm;
362 struct smatch_state *estate;
363 sval_t start, end;
364
365 iter_var = iter_expr->unop;
366 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
367 if (!sm)
368 return NULL;
369 if (!estate_get_single_value(sm->state, &start))
370 return NULL;
371 if (!get_implied_min(condition->right, &end))
372 end = sval_type_min(get_type(iter_var));
373 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
374 return NULL;
375
376 switch (condition->op) {
377 case SPECIAL_NOTEQUAL:
378 case '>':
379 if (!sval_is_min(end) && !sval_is_max(end))
380 end.value++;
381 break;
382 case SPECIAL_GTE:
383 break;
384 default:
385 return NULL;
386 }
387 if (sval_cmp(end, start) > 0)
388 return NULL;
389 estate = alloc_estate_range(end, start);
390 estate_set_hard_max(estate);
391 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
392 set_extra_expr_mod(iter_var, estate);
393 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
394 }
395
396 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
397 {
398 struct expression *iter_expr;
399 struct expression *condition;
400
401 if (!loop->iterator_post_statement)
402 return NULL;
403 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
404 return NULL;
405 iter_expr = loop->iterator_post_statement->expression;
406 if (!loop->iterator_pre_condition)
407 return NULL;
408 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
409 return NULL;
410 condition = loop->iterator_pre_condition;
411
412 if (iter_expr->op == SPECIAL_INCREMENT)
413 return handle_canonical_for_inc(iter_expr, condition);
414 if (iter_expr->op == SPECIAL_DECREMENT)
415 return handle_canonical_for_dec(iter_expr, condition);
416 return NULL;
417 }
418
419 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
420 {
421 struct sm_state *ret;
422
423 __push_fake_cur_stree();
424 if (!loop->iterator_post_statement)
425 ret = handle_canonical_while_count_down(loop);
426 else
427 ret = handle_canonical_for_loops(loop);
428 *stree = __pop_fake_cur_stree();
429 return ret;
430 }
431
432 int __iterator_unchanged(struct sm_state *sm)
433 {
434 if (!sm)
435 return 0;
436 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
437 return 1;
438 return 0;
439 }
440
441 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
442 {
443 sval_t after_value;
444
445 /* paranoid checking. prolly not needed */
446 condition = strip_expr(condition);
447 if (!condition)
448 return;
449 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
450 return;
451 if (condition->op != SPECIAL_DECREMENT)
452 return;
453 after_value = estate_min(sm->state);
454 after_value.value--;
455 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
456 }
457
458 void __extra_pre_loop_hook_after(struct sm_state *sm,
459 struct statement *iterator,
460 struct expression *condition)
461 {
462 struct expression *iter_expr;
463 sval_t limit;
464 struct smatch_state *state;
465
466 if (!iterator) {
467 while_count_down_after(sm, condition);
468 return;
469 }
470
471 iter_expr = iterator->expression;
472
473 if (condition->type != EXPR_COMPARE)
474 return;
475 if (iter_expr->op == SPECIAL_INCREMENT) {
476 limit = sval_binop(estate_max(sm->state), '+',
477 sval_type_val(estate_type(sm->state), 1));
478 } else {
479 limit = sval_binop(estate_min(sm->state), '-',
480 sval_type_val(estate_type(sm->state), 1));
481 }
482 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
483 if (iter_expr->op == SPECIAL_INCREMENT)
484 state = alloc_estate_range(estate_min(sm->state), limit);
485 else
486 state = alloc_estate_range(limit, estate_max(sm->state));
487 } else {
488 state = alloc_estate_sval(limit);
489 }
490 if (!estate_has_hard_max(sm->state)) {
491 estate_clear_hard_max(state);
492 }
493 if (estate_has_fuzzy_max(sm->state)) {
494 sval_t hmax = estate_get_fuzzy_max(sm->state);
495 sval_t max = estate_max(sm->state);
496
497 if (sval_cmp(hmax, max) != 0)
498 estate_clear_fuzzy_max(state);
499 } else if (!estate_has_fuzzy_max(sm->state)) {
500 estate_clear_fuzzy_max(state);
501 }
502
503 set_extra_mod(sm->name, sm->sym, state);
504 }
505
506 static struct stree *unmatched_stree;
507 static struct smatch_state *unmatched_state(struct sm_state *sm)
508 {
509 struct smatch_state *state;
510
511 if (unmatched_stree) {
512 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
513 if (state)
514 return state;
515 }
516 if (parent_is_gone_var_sym(sm->name, sm->sym))
517 return alloc_estate_empty();
518 return alloc_estate_whole(estate_type(sm->state));
519 }
520
521 static void clear_the_pointed_at(struct expression *expr)
522 {
523 struct stree *stree;
524 char *name;
525 struct symbol *sym;
526 struct sm_state *tmp;
527
528 name = expr_to_var_sym(expr, &sym);
529 if (!name || !sym)
530 goto free;
531
532 stree = __get_cur_stree();
533 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
534 if (tmp->name[0] != '*')
535 continue;
536 if (tmp->sym != sym)
537 continue;
538 if (strcmp(tmp->name + 1, name) != 0)
539 continue;
540 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
541 } END_FOR_EACH_SM(tmp);
542
543 free:
544 free_string(name);
545 }
546
547 static void match_function_call(struct expression *expr)
548 {
549 struct expression *arg;
550 struct expression *tmp;
551
552 /* if we have the db this is handled in smatch_function_hooks.c */
553 if (!option_no_db)
554 return;
555 if (inlinable(expr->fn))
556 return;
557
558 FOR_EACH_PTR(expr->args, arg) {
559 tmp = strip_expr(arg);
560 if (tmp->type == EXPR_PREOP && tmp->op == '&')
561 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
562 else
563 clear_the_pointed_at(tmp);
564 } END_FOR_EACH_PTR(arg);
565 }
566
567 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
568 {
569 if (!one || !two)
570 return 0;
571 if (one->type == SYM_PTR && two->type == SYM_PTR)
572 return 1;
573 return types_equiv(one, two);
574 }
575
576 static bool is_non_null_array(struct expression *expr)
577 {
578 struct symbol *type;
579 struct symbol *sym;
580 struct symbol *tmp;
581 char *name;
582 int i;
583
584 type = get_type(expr);
585 if (!type || type->type != SYM_ARRAY)
586 return 0;
587 if (expr->type == EXPR_SYMBOL)
588 return 1;
589 if (implied_not_equal(expr, 0))
590 return 1;
591
592 /* verify that it's not the first member of the struct */
593 if (expr->type != EXPR_DEREF || !expr->member)
594 return 0;
595 name = expr_to_var_sym(expr, &sym);
596 free_string(name);
597 if (!name || !sym)
598 return 0;
599 type = get_real_base_type(sym);
600 if (!type || type->type != SYM_PTR)
601 return 0;
602 type = get_real_base_type(type);
603 if (type->type != SYM_STRUCT)
604 return 0;
605
606 i = 0;
607 FOR_EACH_PTR(type->symbol_list, tmp) {
608 i++;
609 if (!tmp->ident)
610 continue;
611 if (strcmp(expr->member->name, tmp->ident->name) == 0) {
612 if (i == 1)
613 return 0;
614 return 1;
615 }
616 } END_FOR_EACH_PTR(tmp);
617
618 return 0;
619 }
620
621 static void match_vanilla_assign(struct expression *left, struct expression *right)
622 {
623 struct range_list *rl = NULL;
624 struct symbol *right_sym;
625 struct symbol *left_type;
626 struct symbol *right_type;
627 char *right_name = NULL;
628 struct symbol *sym;
629 char *name;
630 sval_t max;
631 struct smatch_state *state;
632
633 if (is_struct(left))
634 return;
635
636 name = expr_to_var_sym(left, &sym);
637 if (!name)
638 return;
639
640 left_type = get_type(left);
641 right_type = get_type(right);
642
643 right_name = expr_to_var_sym(right, &right_sym);
644
645 if (!__in_fake_assign &&
646 !(right->type == EXPR_PREOP && right->op == '&') &&
647 right_name && right_sym &&
648 types_equiv_or_pointer(left_type, right_type) &&
649 !has_symbol(right, sym)) {
650 set_equiv(left, right);
651 goto free;
652 }
653
654 if (is_non_null_array(right)) {
655 state = alloc_estate_range(array_min_sval, array_max_sval);
656 } else if (get_implied_rl(right, &rl)) {
657 rl = cast_rl(left_type, rl);
658 state = alloc_estate_rl(rl);
659 if (get_hard_max(right, &max)) {
660 estate_set_hard_max(state);
661 estate_set_fuzzy_max(state, max);
662 }
663 } else {
664 rl = alloc_whole_rl(right_type);
665 rl = cast_rl(left_type, rl);
666 state = alloc_estate_rl(rl);
667 }
668 set_extra_mod(name, sym, state);
669 free:
670 free_string(right_name);
671 }
672
673 static int op_remove_assign(int op)
674 {
675 switch (op) {
676 case SPECIAL_ADD_ASSIGN:
677 return '+';
678 case SPECIAL_SUB_ASSIGN:
679 return '-';
680 case SPECIAL_MUL_ASSIGN:
681 return '*';
682 case SPECIAL_DIV_ASSIGN:
683 return '/';
684 case SPECIAL_MOD_ASSIGN:
685 return '%';
686 case SPECIAL_AND_ASSIGN:
687 return '&';
688 case SPECIAL_OR_ASSIGN:
689 return '|';
690 case SPECIAL_XOR_ASSIGN:
691 return '^';
692 case SPECIAL_SHL_ASSIGN:
693 return SPECIAL_LEFTSHIFT;
694 case SPECIAL_SHR_ASSIGN:
695 return SPECIAL_RIGHTSHIFT;
696 default:
697 return op;
698 }
699 }
700
701 static void match_assign(struct expression *expr)
702 {
703 struct range_list *rl = NULL;
704 struct expression *left;
705 struct expression *right;
706 struct expression *binop_expr;
707 struct symbol *left_type;
708 struct symbol *right_type;
709 struct symbol *sym;
710 char *name;
711 sval_t left_min, left_max;
712 sval_t right_min, right_max;
713 sval_t res_min, res_max;
714
715 left = strip_expr(expr->left);
716
717 right = strip_expr(expr->right);
718 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
719 right = strip_expr(right->left);
720
721 if (expr->op == '=' && is_condition(expr->right))
722 return; /* handled in smatch_condition.c */
723 if (expr->op == '=' && right->type == EXPR_CALL)
724 return; /* handled in smatch_function_hooks.c */
725 if (expr->op == '=') {
726 match_vanilla_assign(left, right);
727 return;
728 }
729
730 name = expr_to_var_sym(left, &sym);
731 if (!name)
732 return;
733
734 left_type = get_type(left);
735 right_type = get_type(right);
736
737 res_min = sval_type_min(left_type);
738 res_max = sval_type_max(left_type);
739
740 switch (expr->op) {
741 case SPECIAL_ADD_ASSIGN:
742 get_absolute_max(left, &left_max);
743 get_absolute_max(right, &right_max);
744 if (sval_binop_overflows(left_max, '+', right_max))
745 break;
746 if (get_implied_min(left, &left_min) &&
747 !sval_is_negative_min(left_min) &&
748 get_implied_min(right, &right_min) &&
749 !sval_is_negative_min(right_min)) {
750 res_min = sval_binop(left_min, '+', right_min);
751 res_min = sval_cast(right_type, res_min);
752 }
753 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
754 break;
755 res_max = sval_binop(left_max, '+', right_max);
756 res_max = sval_cast(right_type, res_max);
757 break;
758 case SPECIAL_SUB_ASSIGN:
759 if (get_implied_max(left, &left_max) &&
760 !sval_is_max(left_max) &&
761 get_implied_min(right, &right_min) &&
762 !sval_is_min(right_min)) {
763 res_max = sval_binop(left_max, '-', right_min);
764 res_max = sval_cast(right_type, res_max);
765 }
766 if (inside_loop())
767 break;
768 if (get_implied_min(left, &left_min) &&
769 !sval_is_min(left_min) &&
770 get_implied_max(right, &right_max) &&
771 !sval_is_max(right_max)) {
772 res_min = sval_binop(left_min, '-', right_max);
773 res_min = sval_cast(right_type, res_min);
774 }
775 break;
776 case SPECIAL_AND_ASSIGN:
777 case SPECIAL_MOD_ASSIGN:
778 case SPECIAL_SHL_ASSIGN:
779 case SPECIAL_SHR_ASSIGN:
780 case SPECIAL_OR_ASSIGN:
781 case SPECIAL_XOR_ASSIGN:
782 case SPECIAL_MUL_ASSIGN:
783 case SPECIAL_DIV_ASSIGN:
784 binop_expr = binop_expression(expr->left,
785 op_remove_assign(expr->op),
786 expr->right);
787 if (get_absolute_rl(binop_expr, &rl)) {
788 rl = cast_rl(left_type, rl);
789 set_extra_mod(name, sym, alloc_estate_rl(rl));
790 goto free;
791 }
792 break;
793 }
794 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
795 set_extra_mod(name, sym, alloc_estate_rl(rl));
796 free:
797 free_string(name);
798 }
799
800 static struct smatch_state *increment_state(struct smatch_state *state)
801 {
802 sval_t min = estate_min(state);
803 sval_t max = estate_max(state);
804
805 if (!estate_rl(state))
806 return NULL;
807
808 if (inside_loop())
809 max = sval_type_max(max.type);
810
811 if (!sval_is_min(min) && !sval_is_max(min))
812 min.value++;
813 if (!sval_is_min(max) && !sval_is_max(max))
814 max.value++;
815 return alloc_estate_range(min, max);
816 }
817
818 static struct smatch_state *decrement_state(struct smatch_state *state)
819 {
820 sval_t min = estate_min(state);
821 sval_t max = estate_max(state);
822
823 if (!estate_rl(state))
824 return NULL;
825
826 if (inside_loop())
827 min = sval_type_min(min.type);
828
829 if (!sval_is_min(min) && !sval_is_max(min))
830 min.value--;
831 if (!sval_is_min(max) && !sval_is_max(max))
832 max.value--;
833 return alloc_estate_range(min, max);
834 }
835
836 static void unop_expr(struct expression *expr)
837 {
838 struct smatch_state *state;
839
840 if (expr->smatch_flags & Handled)
841 return;
842
843 switch (expr->op) {
844 case SPECIAL_INCREMENT:
845 state = get_state_expr(SMATCH_EXTRA, expr->unop);
846 state = increment_state(state);
847 if (!state)
848 state = alloc_estate_whole(get_type(expr));
849 set_extra_expr_mod(expr->unop, state);
850 break;
851 case SPECIAL_DECREMENT:
852 state = get_state_expr(SMATCH_EXTRA, expr->unop);
853 state = decrement_state(state);
854 if (!state)
855 state = alloc_estate_whole(get_type(expr));
856 set_extra_expr_mod(expr->unop, state);
857 break;
858 default:
859 return;
860 }
861 }
862
863 static void asm_expr(struct statement *stmt)
864 {
865
866 struct expression *expr;
867 struct symbol *type;
868 int state = 0;
869
870 FOR_EACH_PTR(stmt->asm_outputs, expr) {
871 switch (state) {
872 case 0: /* identifier */
873 case 1: /* constraint */
874 state++;
875 continue;
876 case 2: /* expression */
877 state = 0;
878 type = get_type(strip_expr(expr));
879 set_extra_expr_mod(expr, alloc_estate_whole(type));
880 continue;
881 }
882 } END_FOR_EACH_PTR(expr);
883 }
884
885 static void delete_state_tracker(struct tracker *t)
886 {
887 remove_from_equiv(t->name, t->sym);
888 delete_state(t->owner, t->name, t->sym);
889 }
890
891 static void scoped_state_extra(const char *name, struct symbol *sym)
892 {
893 struct tracker *t;
894
895 t = alloc_tracker(SMATCH_EXTRA, name, sym);
896 add_scope_hook((scope_hook *)&delete_state_tracker, t);
897 }
898
899 static void match_declarations(struct symbol *sym)
900 {
901 const char *name;
902
903 if (sym->ident) {
904 name = sym->ident->name;
905 if (!sym->initializer) {
906 set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
907 scoped_state_extra(name, sym);
908 }
909 }
910 }
911
912 static void check_dereference(struct expression *expr)
913 {
914 if (outside_of_function())
915 return;
916 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
917 }
918
919 static void match_dereferences(struct expression *expr)
920 {
921 if (expr->type != EXPR_PREOP)
922 return;
923 check_dereference(expr->unop);
924 }
925
926 static void match_pointer_as_array(struct expression *expr)
927 {
928 if (!is_array(expr))
929 return;
930 check_dereference(get_array_base(expr));
931 }
932
933 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
934 {
935 struct symbol *sym;
936 char *name;
937
938 name = get_variable_from_key(arg, key, &sym);
939 if (!name || !sym)
940 goto free;
941
942 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
943
944 free:
945 free_string(name);
946 }
947
948 static void match_function_def(struct symbol *sym)
949 {
950 struct symbol *arg;
951
952 FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
953 if (!arg->ident)
954 continue;
955 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
956 } END_FOR_EACH_PTR(arg);
957 }
958
959 static sval_t add_one(sval_t sval)
960 {
961 sval.value++;
962 return sval;
963 }
964
965 static sval_t sub_one(sval_t sval)
966 {
967 sval.value--;
968 return sval;
969 }
970
971 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
972 {
973 struct range_list *left_orig;
974 struct range_list *left_true;
975 struct range_list *left_false;
976 struct range_list *right_orig;
977 struct range_list *right_true;
978 struct range_list *right_false;
979 struct smatch_state *left_true_state;
980 struct smatch_state *left_false_state;
981 struct smatch_state *right_true_state;
982 struct smatch_state *right_false_state;
983 sval_t min, max, dummy, hard_max;
984 int left_postop = 0;
985 int right_postop = 0;
986
987 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
988 if (left->type == EXPR_POSTOP) {
989 left->smatch_flags |= Handled;
990 left_postop = left->op;
991 }
992 left = strip_expr(left->unop);
993 }
994 while (left->type == EXPR_ASSIGNMENT)
995 left = strip_expr(left->left);
996
997 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
998 if (right->type == EXPR_POSTOP) {
999 right->smatch_flags |= Handled;
1000 right_postop = right->op;
1001 }
1002 right = strip_expr(right->unop);
1003 }
1004
1005 if (get_implied_rl(left, &left_orig)) {
1006 left_orig = cast_rl(type, left_orig);
1007 } else {
1008 min = sval_type_min(get_type(left));
1009 max = sval_type_max(get_type(left));
1010 left_orig = cast_rl(type, alloc_rl(min, max));
1011 }
1012
1013 if (get_implied_rl(right, &right_orig)) {
1014 right_orig = cast_rl(type, right_orig);
1015 } else {
1016 min = sval_type_min(get_type(right));
1017 max = sval_type_max(get_type(right));
1018 right_orig = cast_rl(type, alloc_rl(min, max));
1019 }
1020 min = sval_type_min(type);
1021 max = sval_type_max(type);
1022
1023 left_true = clone_rl(left_orig);
1024 left_false = clone_rl(left_orig);
1025 right_true = clone_rl(right_orig);
1026 right_false = clone_rl(right_orig);
1027
1028 switch (op) {
1029 case '<':
1030 case SPECIAL_UNSIGNED_LT:
1031 left_true = remove_range(left_orig, rl_max(right_orig), max);
1032 if (!sval_is_min(rl_min(right_orig))) {
1033 left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1034 }
1035
1036 right_true = remove_range(right_orig, min, rl_min(left_orig));
1037 if (!sval_is_max(rl_max(left_orig)))
1038 right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1039 break;
1040 case SPECIAL_UNSIGNED_LTE:
1041 case SPECIAL_LTE:
1042 if (!sval_is_max(rl_max(right_orig)))
1043 left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1044 left_false = remove_range(left_orig, min, rl_min(right_orig));
1045
1046 if (!sval_is_min(rl_min(left_orig)))
1047 right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1048 right_false = remove_range(right_orig, rl_max(left_orig), max);
1049
1050 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1051 left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
1052 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1053 right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
1054 break;
1055 case SPECIAL_EQUAL:
1056 if (!sval_is_max(rl_max(right_orig))) {
1057 left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
1058 }
1059 if (!sval_is_min(rl_min(right_orig))) {
1060 left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
1061 }
1062 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1063 left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1064
1065 if (!sval_is_max(rl_max(left_orig)))
1066 right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
1067 if (!sval_is_min(rl_min(left_orig)))
1068 right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
1069 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1070 right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1071 break;
1072 case SPECIAL_UNSIGNED_GTE:
1073 case SPECIAL_GTE:
1074 if (!sval_is_min(rl_min(right_orig)))
1075 left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1076 left_false = remove_range(left_orig, rl_max(right_orig), max);
1077
1078 if (!sval_is_max(rl_max(left_orig)))
1079 right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1080 right_false = remove_range(right_orig, min, rl_min(left_orig));
1081
1082 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1083 right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
1084 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1085 left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
1086 break;
1087 case '>':
1088 case SPECIAL_UNSIGNED_GT:
1089 left_true = remove_range(left_orig, min, rl_min(right_orig));
1090 if (!sval_is_max(rl_max(right_orig)))
1091 left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1092
1093 right_true = remove_range(right_orig, rl_max(left_orig), max);
1094 if (!sval_is_min(rl_min(left_orig)))
1095 right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1096 break;
1097 case SPECIAL_NOTEQUAL:
1098 if (!sval_is_max(rl_max(right_orig)))
1099 left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
1100 if (!sval_is_min(rl_min(right_orig)))
1101 left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
1102 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1103 left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1104
1105 if (!sval_is_max(rl_max(left_orig)))
1106 right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
1107 if (!sval_is_min(rl_min(left_orig)))
1108 right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
1109 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1110 right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1111 break;
1112 default:
1113 return;
1114 }
1115
1116 left_true = rl_truncate_cast(get_type(left), left_true);
1117 left_false = rl_truncate_cast(get_type(left), left_false);
1118 right_true = rl_truncate_cast(get_type(right), right_true);
1119 right_false = rl_truncate_cast(get_type(right), right_false);
1120
1121 left_true_state = alloc_estate_rl(left_true);
1122 left_false_state = alloc_estate_rl(left_false);
1123 right_true_state = alloc_estate_rl(right_true);
1124 right_false_state = alloc_estate_rl(right_false);
1125
1126 switch (op) {
1127 case '<':
1128 case SPECIAL_UNSIGNED_LT:
1129 case SPECIAL_UNSIGNED_LTE:
1130 case SPECIAL_LTE:
1131 if (get_hard_max(right, &dummy))
1132 estate_set_hard_max(left_true_state);
1133 if (get_hard_max(left, &dummy))
1134 estate_set_hard_max(right_false_state);
1135 break;
1136 case '>':
1137 case SPECIAL_UNSIGNED_GT:
1138 case SPECIAL_UNSIGNED_GTE:
1139 case SPECIAL_GTE:
1140 if (get_hard_max(left, &dummy))
1141 estate_set_hard_max(right_true_state);
1142 if (get_hard_max(right, &dummy))
1143 estate_set_hard_max(left_false_state);
1144 break;
1145 }
1146
1147 switch (op) {
1148 case '<':
1149 case SPECIAL_UNSIGNED_LT:
1150 case SPECIAL_UNSIGNED_LTE:
1151 case SPECIAL_LTE:
1152 if (get_hard_max(right, &hard_max)) {
1153 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1154 hard_max.value--;
1155 estate_set_fuzzy_max(left_true_state, hard_max);
1156 }
1157 if (get_implied_value(right, &hard_max)) {
1158 if (op == SPECIAL_UNSIGNED_LTE ||
1159 op == SPECIAL_LTE)
1160 hard_max.value++;
1161 estate_set_fuzzy_max(left_false_state, hard_max);
1162 }
1163 if (get_hard_max(left, &hard_max)) {
1164 if (op == SPECIAL_UNSIGNED_LTE ||
1165 op == SPECIAL_LTE)
1166 hard_max.value--;
1167 estate_set_fuzzy_max(right_false_state, hard_max);
1168 }
1169 if (get_implied_value(left, &hard_max)) {
1170 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1171 hard_max.value++;
1172 estate_set_fuzzy_max(right_true_state, hard_max);
1173 }
1174 break;
1175 case '>':
1176 case SPECIAL_UNSIGNED_GT:
1177 case SPECIAL_UNSIGNED_GTE:
1178 case SPECIAL_GTE:
1179 if (get_hard_max(left, &hard_max)) {
1180 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1181 hard_max.value--;
1182 estate_set_fuzzy_max(right_true_state, hard_max);
1183 }
1184 if (get_implied_value(left, &hard_max)) {
1185 if (op == SPECIAL_UNSIGNED_GTE ||
1186 op == SPECIAL_GTE)
1187 hard_max.value++;
1188 estate_set_fuzzy_max(right_false_state, hard_max);
1189 }
1190 if (get_hard_max(right, &hard_max)) {
1191 if (op == SPECIAL_UNSIGNED_LTE ||
1192 op == SPECIAL_LTE)
1193 hard_max.value--;
1194 estate_set_fuzzy_max(left_false_state, hard_max);
1195 }
1196 if (get_implied_value(right, &hard_max)) {
1197 if (op == '>' ||
1198 op == SPECIAL_UNSIGNED_GT)
1199 hard_max.value++;
1200 estate_set_fuzzy_max(left_true_state, hard_max);
1201 }
1202 break;
1203 case SPECIAL_EQUAL:
1204 if (get_hard_max(left, &hard_max))
1205 estate_set_fuzzy_max(right_true_state, hard_max);
1206 if (get_hard_max(right, &hard_max))
1207 estate_set_fuzzy_max(left_true_state, hard_max);
1208 break;
1209 }
1210
1211 if (get_hard_max(left, &hard_max)) {
1212 estate_set_hard_max(left_true_state);
1213 estate_set_hard_max(left_false_state);
1214 }
1215 if (get_hard_max(right, &hard_max)) {
1216 estate_set_hard_max(right_true_state);
1217 estate_set_hard_max(right_false_state);
1218 }
1219
1220 if (left_postop == SPECIAL_INCREMENT) {
1221 left_true_state = increment_state(left_true_state);
1222 left_false_state = increment_state(left_false_state);
1223 }
1224 if (left_postop == SPECIAL_DECREMENT) {
1225 left_true_state = decrement_state(left_true_state);
1226 left_false_state = decrement_state(left_false_state);
1227 }
1228 if (right_postop == SPECIAL_INCREMENT) {
1229 right_true_state = increment_state(right_true_state);
1230 right_false_state = increment_state(right_false_state);
1231 }
1232 if (right_postop == SPECIAL_DECREMENT) {
1233 right_true_state = decrement_state(right_true_state);
1234 right_false_state = decrement_state(right_false_state);
1235 }
1236
1237 set_extra_expr_true_false(left, left_true_state, left_false_state);
1238 set_extra_expr_true_false(right, right_true_state, right_false_state);
1239 }
1240
1241 static int is_simple_math(struct expression *expr)
1242 {
1243 if (!expr)
1244 return 0;
1245 if (expr->type != EXPR_BINOP)
1246 return 0;
1247 switch (expr->op) {
1248 case '+':
1249 case '-':
1250 case '*':
1251 return 1;
1252 }
1253 return 0;
1254 }
1255
1256 static void move_known_values(struct expression **left_p, struct expression **right_p)
1257 {
1258 struct expression *left = *left_p;
1259 struct expression *right = *right_p;
1260 sval_t sval;
1261
1262 if (get_implied_value(left, &sval)) {
1263 if (!is_simple_math(right))
1264 return;
1265 if (right->op == '*') {
1266 sval_t divisor;
1267
1268 if (!get_value(right->right, &divisor))
1269 return;
1270 if (divisor.value == 0 && sval.value % divisor.value)
1271 return;
1272 *left_p = binop_expression(left, invert_op(right->op), right->right);
1273 *right_p = right->left;
1274 return;
1275 }
1276 if (right->op == '+' && get_value(right->left, &sval)) {
1277 *left_p = binop_expression(left, invert_op(right->op), right->left);
1278 *right_p = right->right;
1279 return;
1280 }
1281 if (get_value(right->right, &sval)) {
1282 *left_p = binop_expression(left, invert_op(right->op), right->right);
1283 *right_p = right->left;
1284 return;
1285 }
1286 return;
1287 }
1288 if (get_implied_value(right, &sval)) {
1289 if (!is_simple_math(left))
1290 return;
1291 if (left->op == '*') {
1292 sval_t divisor;
1293
1294 if (!get_value(left->right, &divisor))
1295 return;
1296 if (divisor.value == 0 && sval.value % divisor.value)
1297 return;
1298 *right_p = binop_expression(right, invert_op(left->op), left->right);
1299 *left_p = left->left;
1300 return;
1301 }
1302 if (left->op == '+' && get_value(left->left, &sval)) {
1303 *right_p = binop_expression(right, invert_op(left->op), left->left);
1304 *left_p = left->right;
1305 return;
1306 }
1307
1308 if (get_value(left->right, &sval)) {
1309 *right_p = binop_expression(right, invert_op(left->op), left->right);
1310 *left_p = left->left;
1311 return;
1312 }
1313 return;
1314 }
1315 }
1316
1317 static int match_func_comparison(struct expression *expr)
1318 {
1319 struct expression *left = strip_expr(expr->left);
1320 struct expression *right = strip_expr(expr->right);
1321 sval_t sval;
1322
1323 /*
1324 * fixme: think about this harder. We should always be trying to limit
1325 * the non-call side as well. If we can't determine the limitter does
1326 * that mean we aren't querying the database and are missing important
1327 * information?
1328 */
1329
1330 if (left->type == EXPR_CALL) {
1331 if (get_implied_value(left, &sval)) {
1332 handle_comparison(get_type(expr), left, expr->op, right);
1333 return 1;
1334 }
1335 function_comparison(left, expr->op, right);
1336 return 1;
1337 }
1338
1339 if (right->type == EXPR_CALL) {
1340 if (get_implied_value(right, &sval)) {
1341 handle_comparison(get_type(expr), left, expr->op, right);
1342 return 1;
1343 }
1344 function_comparison(left, expr->op, right);
1345 return 1;
1346 }
1347
1348 return 0;
1349 }
1350
1351 static void match_comparison(struct expression *expr)
1352 {
1353 struct expression *left_orig = strip_expr(expr->left);
1354 struct expression *right_orig = strip_expr(expr->right);
1355 struct expression *left, *right;
1356 struct expression *prev;
1357 struct symbol *type;
1358
1359 if (match_func_comparison(expr))
1360 return;
1361
1362 type = get_type(expr);
1363 if (!type)
1364 type = &llong_ctype;
1365
1366 left = left_orig;
1367 right = right_orig;
1368 move_known_values(&left, &right);
1369 handle_comparison(type, left, expr->op, right);
1370
1371 prev = get_assigned_expr(left_orig);
1372 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1373 left = prev;
1374 right = right_orig;
1375 move_known_values(&left, &right);
1376 handle_comparison(type, left, expr->op, right);
1377 }
1378
1379 prev = get_assigned_expr(right_orig);
1380 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1381 left = left_orig;
1382 right = prev;
1383 move_known_values(&left, &right);
1384 handle_comparison(type, left, expr->op, right);
1385 }
1386 }
1387
1388 static void handle_AND_condition(struct expression *expr)
1389 {
1390 struct range_list *rl = NULL;
1391 sval_t known;
1392
1393 if (get_implied_value(expr->left, &known) && known.value > 0) {
1394 known.value--;
1395 get_absolute_rl(expr->right, &rl);
1396 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1397 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1398 return;
1399 }
1400
1401 if (get_implied_value(expr->right, &known) && known.value > 0) {
1402 known.value--;
1403 get_absolute_rl(expr->left, &rl);
1404 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1405 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1406 return;
1407 }
1408 }
1409
1410 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1411 void __extra_match_condition(struct expression *expr)
1412 {
1413 struct symbol *sym;
1414 char *name;
1415 struct smatch_state *pre_state;
1416 struct smatch_state *true_state;
1417 struct smatch_state *false_state;
1418
1419 expr = strip_expr(expr);
1420 switch (expr->type) {
1421 case EXPR_CALL:
1422 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1423 return;
1424 case EXPR_PREOP:
1425 case EXPR_SYMBOL:
1426 case EXPR_DEREF: {
1427 sval_t zero;
1428
1429 zero = sval_blank(expr);
1430 zero.value = 0;
1431
1432 name = expr_to_var_sym(expr, &sym);
1433 if (!name)
1434 return;
1435 pre_state = get_state(my_id, name, sym);
1436 true_state = estate_filter_sval(pre_state, zero);
1437 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1438 false_state = alloc_estate_sval(zero);
1439 else
1440 false_state = alloc_estate_empty();
1441 set_extra_true_false(name, sym, true_state, false_state);
1442 free_string(name);
1443 return;
1444 }
1445 case EXPR_COMPARE:
1446 match_comparison(expr);
1447 return;
1448 case EXPR_ASSIGNMENT:
1449 __extra_match_condition(expr->left);
1450 return;
1451 case EXPR_BINOP:
1452 if (expr->op == '&')
1453 handle_AND_condition(expr);
1454 return;
1455 }
1456 }
1457
1458 static void assume_indexes_are_valid(struct expression *expr)
1459 {
1460 struct expression *array_expr;
1461 int array_size;
1462 struct expression *offset;
1463 struct symbol *offset_type;
1464 struct range_list *rl_before;
1465 struct range_list *rl_after;
1466 struct range_list *filter = NULL;
1467 sval_t size;
1468
1469 expr = strip_expr(expr);
1470 if (!is_array(expr))
1471 return;
1472
1473 offset = get_array_offset(expr);
1474 offset_type = get_type(offset);
1475 if (offset_type && type_signed(offset_type)) {
1476 filter = alloc_rl(sval_type_min(offset_type),
1477 sval_type_val(offset_type, -1));
1478 }
1479
1480 array_expr = get_array_base(expr);
1481 array_size = get_real_array_size(array_expr);
1482 if (array_size > 1) {
1483 size = sval_type_val(offset_type, array_size);
1484 add_range(&filter, size, sval_type_max(offset_type));
1485 }
1486
1487 if (!filter)
1488 return;
1489 get_absolute_rl(offset, &rl_before);
1490 rl_after = rl_filter(rl_before, filter);
1491 if (rl_equiv(rl_before, rl_after))
1492 return;
1493 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1494 }
1495
1496 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1497 int implied_not_equal(struct expression *expr, long long val)
1498 {
1499 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1500 }
1501
1502 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1503 {
1504 struct smatch_state *estate;
1505
1506 estate = get_state(SMATCH_EXTRA, name, sym);
1507 if (!estate)
1508 return 0;
1509 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1510 return 1;
1511 return 0;
1512 }
1513
1514 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1515 {
1516 char buf[256];
1517 char *start;
1518 char *end;
1519 struct smatch_state *state;
1520
1521 strncpy(buf, name, sizeof(buf) - 1);
1522 buf[sizeof(buf) - 1] = '\0';
1523
1524 start = &buf[0];
1525 while (*start == '*') {
1526 start++;
1527 state = get_state(SMATCH_EXTRA, start, sym);
1528 if (!state)
1529 continue;
1530 if (!estate_rl(state))
1531 return 1;
1532 if (estate_min(state).value == 0 &&
1533 estate_max(state).value == 0)
1534 return 1;
1535 }
1536
1537 start = &buf[0];
1538 while (*start == '&')
1539 start++;
1540
1541 while ((end = strrchr(start, '-'))) {
1542 *end = '\0';
1543 state = get_state(SMATCH_EXTRA, start, sym);
1544 if (!state)
1545 continue;
1546 if (estate_min(state).value == 0 &&
1547 estate_max(state).value == 0)
1548 return 1;
1549 }
1550 return 0;
1551 }
1552
1553 int parent_is_null(struct expression *expr)
1554 {
1555 struct symbol *sym;
1556 char *var;
1557 int ret = 0;
1558
1559 expr = strip_expr(expr);
1560 var = expr_to_var_sym(expr, &sym);
1561 if (!var || !sym)
1562 goto free;
1563 ret = parent_is_null_var_sym(var, sym);
1564 free:
1565 free_string(var);
1566 return ret;
1567 }
1568
1569 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
1570 {
1571 *(int *)found = 1;
1572 return 0;
1573 }
1574
1575 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1576 {
1577 sval_t sval;
1578 int found = 0;
1579
1580 /* for function pointers assume everything is used */
1581 if (call->fn->type != EXPR_SYMBOL)
1582 return 0;
1583
1584 /*
1585 * kzalloc() information is treated as special because so there is just
1586 * a lot of stuff initialized to zero and it makes building the database
1587 * take hours and hours.
1588 *
1589 * In theory, we should just remove this line and not pass any unused
1590 * information, but I'm not sure enough that this code works so I want
1591 * to hold off on that for now.
1592 */
1593 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
1594 return 0;
1595
1596 run_sql(&param_used_callback, &found,
1597 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
1598 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
1599 if (found)
1600 return 0;
1601
1602 /* If the database is not built yet, then assume everything is used */
1603 run_sql(&param_used_callback, &found,
1604 "select * from call_implies where %s and type = %d;",
1605 get_static_filter(call->fn->symbol), PARAM_USED);
1606 if (!found)
1607 return 0;
1608
1609 return 1;
1610 }
1611
1612 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1613 {
1614 if (estate_is_whole(sm->state))
1615 return;
1616 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
1617 return;
1618 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, sm->state->name);
1619 if (estate_has_fuzzy_max(sm->state))
1620 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1621 sval_to_str(estate_get_fuzzy_max(sm->state)));
1622 }
1623
1624 static void db_limited_before(void)
1625 {
1626 unmatched_stree = clone_stree(__get_cur_stree());
1627 }
1628
1629 static void db_limited_after(void)
1630 {
1631 free_stree(&unmatched_stree);
1632 }
1633
1634 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
1635 {
1636 struct expression *arg;
1637 char *name;
1638 struct symbol *sym;
1639 struct sm_state *sm;
1640 struct symbol *compare_type, *var_type;
1641 struct range_list *rl;
1642 struct range_list *limit;
1643 struct range_list *new;
1644
1645 while (expr->type == EXPR_ASSIGNMENT)
1646 expr = strip_expr(expr->right);
1647 if (expr->type != EXPR_CALL)
1648 return;
1649
1650 arg = get_argument_from_call_expr(expr->args, param);
1651 if (!arg)
1652 return;
1653
1654 name = get_variable_from_key(arg, key, &sym);
1655 if (!name || !sym)
1656 goto free;
1657
1658 if (strcmp(key, "$") == 0)
1659 compare_type = get_arg_type(expr->fn, param);
1660 else
1661 compare_type = get_member_type_from_key(arg, key);
1662
1663 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1664 if (sm)
1665 rl = estate_rl(sm->state);
1666 else
1667 rl = alloc_whole_rl(compare_type);
1668
1669 call_results_to_rl(expr, compare_type, value, &limit);
1670 new = rl_intersection(rl, limit);
1671
1672 var_type = get_member_type_from_key(arg, key);
1673 new = cast_rl(var_type, new);
1674
1675 /* We want to preserve the implications here */
1676 if (sm && rl_equiv(estate_rl(sm->state), new))
1677 __set_sm(sm);
1678 else {
1679 if (op == PARAM_LIMIT)
1680 set_extra_nomod(name, sym, alloc_estate_rl(new));
1681 else
1682 set_extra_mod(name, sym, alloc_estate_rl(new));
1683 }
1684
1685 free:
1686 free_string(name);
1687 }
1688
1689 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1690 {
1691 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
1692 }
1693
1694 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1695 {
1696 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
1697 }
1698
1699 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
1700 {
1701 struct expression *arg;
1702 char *name;
1703 struct symbol *sym;
1704 struct symbol *type;
1705 struct smatch_state *state;
1706 struct range_list *new = NULL;
1707 struct range_list *added = NULL;
1708
1709 while (expr->type == EXPR_ASSIGNMENT)
1710 expr = strip_expr(expr->right);
1711 if (expr->type != EXPR_CALL)
1712 return;
1713
1714 arg = get_argument_from_call_expr(expr->args, param);
1715 if (!arg)
1716 return;
1717 type = get_member_type_from_key(arg, key);
1718 name = get_variable_from_key(arg, key, &sym);
1719 if (!name || !sym)
1720 goto free;
1721
1722 state = get_state(SMATCH_EXTRA, name, sym);
1723 if (state)
1724 new = estate_rl(state);
1725
1726 call_results_to_rl(expr, type, value, &added);
1727
1728 if (op == PARAM_SET)
1729 new = added;
1730 else
1731 new = rl_union(new, added);
1732
1733 set_extra_mod(name, sym, alloc_estate_rl(new));
1734 free:
1735 free_string(name);
1736 }
1737
1738 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1739 {
1740 db_param_add_set(expr, param, key, value, PARAM_ADD);
1741 }
1742
1743 static void db_param_set(struct expression *expr, int param, char *key, char *value)
1744 {
1745 db_param_add_set(expr, param, key, value, PARAM_SET);
1746 }
1747
1748 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1749 {
1750 struct symbol *type;
1751 struct symbol *sym;
1752 char *name;
1753 struct range_list *rl;
1754
1755 if (expr->type != EXPR_ASSIGNMENT)
1756 return;
1757
1758 name = return_state_to_var_sym(expr, param, key, &sym);
1759 if (!name || !sym)
1760 goto free;
1761 type = get_member_type_from_key(expr->left, key);
1762 if (!type)
1763 return;
1764 call_results_to_rl(expr->right, type, value, &rl);
1765 set_extra_mod(name, sym, alloc_estate_rl(rl));
1766
1767 free:
1768 free_string(name);
1769 }
1770
1771 static char *in_terms_of_param_math(struct expression *expr, char *printed_name)
1772 {
1773 struct symbol *sym;
1774 char *var;
1775 char buf[256];
1776 char *ret = NULL;
1777
1778 var = expr_to_var_sym(expr, &sym);
1779 if (!var || !sym)
1780 goto free;
1781 snprintf(buf, sizeof(buf), "%s%s", var, printed_name + 2);
1782
1783 ret = get_value_in_terms_of_parameter_math_var_sym(buf, sym);
1784
1785 free:
1786 free_string(var);
1787 return ret;
1788 }
1789
1790 static void returned_member_callback(int return_id, char *return_ranges, struct expression *expr, char *printed_name, struct smatch_state *state)
1791 {
1792 char buf[256];
1793 char *math_str;
1794 sval_t sval;
1795
1796 /* these are handled in smatch_param_filter/set/limit.c */
1797 if (printed_name[0] != '*' &&
1798 !strchr(printed_name, '.') && !strchr(printed_name, '-'))
1799 return;
1800
1801 if (estate_get_single_value(state, &sval)) {
1802 sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1803 printed_name, sval_to_str(sval));
1804 return;
1805 }
1806
1807 math_str = in_terms_of_param_math(expr, printed_name);
1808 if (math_str) {
1809 snprintf(buf, sizeof(buf), "%s[%s]", state->name, math_str);
1810 sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1811 printed_name, buf);
1812 return;
1813 }
1814
1815 if (estate_is_whole(state))
1816 return;
1817
1818 sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1819 printed_name, state->name);
1820 }
1821
1822 static void match_call_info(struct expression *expr)
1823 {
1824 struct smatch_state *state;
1825 struct range_list *rl = NULL;
1826 struct expression *arg;
1827 struct symbol *type;
1828 int i = 0;
1829
1830 FOR_EACH_PTR(expr->args, arg) {
1831 type = get_arg_type(expr->fn, i);
1832
1833 if (get_implied_rl(arg, &rl))
1834 rl = cast_rl(type, rl);
1835 else
1836 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1837
1838 if (!is_whole_rl(rl))
1839 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
1840 state = get_state_expr(SMATCH_EXTRA, arg);
1841 if (estate_has_fuzzy_max(state)) {
1842 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
1843 sval_to_str(estate_get_fuzzy_max(state)));
1844 }
1845 i++;
1846 } END_FOR_EACH_PTR(arg);
1847 }
1848
1849 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1850 {
1851 struct range_list *rl = NULL;
1852 struct smatch_state *state;
1853 struct symbol *type;
1854 char fullname[256];
1855
1856 if (strcmp(key, "*$") == 0)
1857 snprintf(fullname, sizeof(fullname), "*%s", name);
1858 else if (strncmp(key, "$", 1) == 0)
1859 snprintf(fullname, 256, "%s%s", name, key + 1);
1860 else
1861 return;
1862
1863 type = get_member_type_from_key(symbol_expression(sym), key);
1864 str_to_rl(type, value, &rl);
1865 state = alloc_estate_rl(rl);
1866 set_state(SMATCH_EXTRA, fullname, sym, state);
1867 }
1868
1869 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
1870 {
1871 struct range_list *rl = NULL;
1872 struct smatch_state *state;
1873 struct symbol *type;
1874 char fullname[256];
1875 sval_t max;
1876
1877 if (strcmp(key, "*$") == 0)
1878 snprintf(fullname, sizeof(fullname), "*%s", name);
1879 else if (strncmp(key, "$", 1) == 0)
1880 snprintf(fullname, 256, "%s%s", name, key + 1);
1881 else
1882 return;
1883
1884 state = get_state(SMATCH_EXTRA, fullname, sym);
1885 if (!state)
1886 return;
1887 type = get_member_type_from_key(symbol_expression(sym), key);
1888 str_to_rl(type, value, &rl);
1889 if (!rl_to_sval(rl, &max))
1890 return;
1891 estate_set_fuzzy_max(state, max);
1892 }
1893
1894 void register_smatch_extra(int id)
1895 {
1896 my_id = id;
1897
1898 add_merge_hook(my_id, &merge_estates);
1899 add_unmatched_state_hook(my_id, &unmatched_state);
1900 add_hook(&match_function_def, FUNC_DEF_HOOK);
1901 add_hook(&match_declarations, DECLARATION_HOOK);
1902 select_caller_info_hook(set_param_value, PARAM_VALUE);
1903 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
1904 select_return_states_hook(RETURN_VALUE, &db_returned_member_info);
1905 select_return_states_before(&db_limited_before);
1906 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
1907 select_return_states_hook(PARAM_FILTER, &db_param_filter);
1908 select_return_states_hook(PARAM_ADD, &db_param_add);
1909 select_return_states_hook(PARAM_SET, &db_param_set);
1910 select_return_states_after(&db_limited_after);
1911 }
1912
1913 void register_smatch_extra_late(int id)
1914 {
1915 add_hook(&match_dereferences, DEREF_HOOK);
1916 add_hook(&match_pointer_as_array, OP_HOOK);
1917 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
1918 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1919 add_hook(&match_assign, ASSIGNMENT_HOOK);
1920 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
1921 add_hook(&unop_expr, OP_HOOK);
1922 add_hook(&asm_expr, ASM_HOOK);
1923
1924 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1925 add_member_info_callback(my_id, struct_member_callback);
1926 add_returned_member_callback(my_id, returned_member_callback);
1927
1928 add_hook(&assume_indexes_are_valid, OP_HOOK);
1929 }
Static analysis for C