?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
extra: fix a memory leak
[smatch.git] / smatch_extra.c
blob6af13b5262d6af99ddf77577ce6e12c769b7f015
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 static int link_id;
36
37 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr);
38
39 struct string_list *__ignored_macros = NULL;
40 static int in_warn_on_macro(void)
41 {
42 struct statement *stmt;
43 char *tmp;
44 char *macro;
45
46 stmt = get_current_statement();
47 if (!stmt)
48 return 0;
49 macro = get_macro_name(stmt->pos);
50 if (!macro)
51 return 0;
52
53 FOR_EACH_PTR(__ignored_macros, tmp) {
54 if (!strcmp(tmp, macro))
55 return 1;
56 } END_FOR_EACH_PTR(tmp);
57 return 0;
58 }
59
60 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
61 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
62 static struct void_fn_list *extra_mod_hooks;
63 void add_extra_mod_hook(mod_hook *fn)
64 {
65 mod_hook **p = malloc(sizeof(mod_hook *));
66 *p = fn;
67 add_ptr_list(&extra_mod_hooks, p);
68 }
69
70 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
71 {
72 mod_hook **fn;
73
74 FOR_EACH_PTR(extra_mod_hooks, fn) {
75 (*fn)(name, sym, state);
76 } END_FOR_EACH_PTR(fn);
77 }
78
79 struct sm_state *set_extra_mod_helper(const char *name, struct symbol *sym, struct smatch_state *state)
80 {
81 remove_from_equiv(name, sym);
82 call_extra_mod_hooks(name, sym, state);
83 if (__in_fake_assign && estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
84 return NULL;
85 return set_state(SMATCH_EXTRA, name, sym, state);
86 }
87
88 static char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
89 {
90 struct expression *assigned;
91 char *orig_name = NULL;
92 char buf[256];
93 char *ret = NULL;
94 int skip;
95
96 *new_sym = NULL;
97
98 if (!sym->ident)
99 return NULL;
100
101 skip = strlen(sym->ident->name);
102 if (name[skip] != '-' || name[skip + 1] != '>')
103 return NULL;
104 skip += 2;
105
106 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
107 if (!assigned)
108 return NULL;
109 if (assigned->type == EXPR_PREOP || assigned->op == '&') {
110
111 orig_name = expr_to_var_sym(assigned, new_sym);
112 if (!orig_name || !*new_sym)
113 goto free;
114
115 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + skip);
116 ret = alloc_string(buf);
117 free_string(orig_name);
118 return ret;
119 }
120
121 if (assigned->type != EXPR_DEREF)
122 goto free;
123
124 orig_name = expr_to_var_sym(assigned, new_sym);
125 if (!orig_name || !*new_sym)
126 goto free;
127
128 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + skip);
129 ret = alloc_string(buf);
130 free_string(orig_name);
131 return ret;
132
133 free:
134 free_string(orig_name);
135 return NULL;
136 }
137
138 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
139 {
140 char *new_name;
141 struct symbol *new_sym;
142 struct sm_state *sm;
143
144 if (in_warn_on_macro())
145 return NULL;
146 sm = set_extra_mod_helper(name, sym, state);
147 new_name = get_other_name_sym(name, sym, &new_sym);
148 if (new_name && new_sym)
149 set_extra_mod_helper(new_name, new_sym, state);
150 free_string(new_name);
151 return sm;
152 }
153
154 static void clear_array_states(struct expression *array)
155 {
156 struct sm_state *sm;
157
158 sm = get_sm_state_expr(link_id, array);
159 if (sm)
160 match_link_modify(sm, NULL);
161 }
162
163 static struct sm_state *set_extra_array_mod(struct expression *expr, struct smatch_state *state)
164 {
165 struct expression *array;
166 struct expression *offset;
167 struct var_sym_list *vsl;
168 struct var_sym *vs;
169 char *name;
170 struct symbol *sym;
171 sval_t sval;
172 struct sm_state *ret = NULL;
173
174 array = get_array_base(expr);
175 offset = get_array_offset(expr);
176
177 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
178
179 if (!name || !vsl || !get_value(offset, &sval)) {
180 clear_array_states(array);
181 goto free;
182 }
183
184 FOR_EACH_PTR(vsl, vs) {
185 store_link(link_id, vs->var, vs->sym, name, sym);
186 } END_FOR_EACH_PTR(vs);
187
188 ret = set_state(SMATCH_EXTRA, name, sym, state);
189 free:
190 free_string(name);
191 return ret;
192 }
193
194 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
195 {
196 struct symbol *sym;
197 char *name;
198 struct sm_state *ret = NULL;
199
200 if (is_array(expr))
201 return set_extra_array_mod(expr, state);
202
203 expr = strip_expr(expr);
204 name = expr_to_var_sym(expr, &sym);
205 if (!name || !sym)
206 goto free;
207 ret = set_extra_mod(name, sym, state);
208 free:
209 free_string(name);
210 return ret;
211 }
212
213 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
214 {
215 char *new_name;
216 struct symbol *new_sym;
217 struct relation *rel;
218 struct smatch_state *orig_state;
219
220 orig_state = get_state(SMATCH_EXTRA, name, sym);
221
222 new_name = get_other_name_sym(name, sym, &new_sym);
223 if (new_name && new_sym)
224 set_state(SMATCH_EXTRA, new_name, new_sym, state);
225 free_string(new_name);
226
227 if (!estate_related(orig_state)) {
228 set_state(SMATCH_EXTRA, name, sym, state);
229 return;
230 }
231
232 set_related(state, estate_related(orig_state));
233 FOR_EACH_PTR(estate_related(orig_state), rel) {
234 if (option_debug_related)
235 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
236 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
237 } END_FOR_EACH_PTR(rel);
238 }
239
240 /*
241 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
242 */
243 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
244 {
245 char *name;
246 struct symbol *sym;
247
248 name = expr_to_var_sym(expr, &sym);
249 if (!name || !sym)
250 goto free;
251 set_extra_nomod(name, sym, state);
252 free:
253 free_string(name);
254
255 }
256
257 static void set_extra_true_false(const char *name, struct symbol *sym,
258 struct smatch_state *true_state,
259 struct smatch_state *false_state)
260 {
261 char *new_name;
262 struct symbol *new_sym;
263 struct relation *rel;
264 struct smatch_state *orig_state;
265
266 if (in_warn_on_macro())
267 return;
268
269 new_name = get_other_name_sym(name, sym, &new_sym);
270 if (new_name && new_sym)
271 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
272 free_string(new_name);
273
274 orig_state = get_state(SMATCH_EXTRA, name, sym);
275
276 if (!estate_related(orig_state)) {
277 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
278 return;
279 }
280
281 if (true_state)
282 set_related(true_state, estate_related(orig_state));
283 if (false_state)
284 set_related(false_state, estate_related(orig_state));
285
286 FOR_EACH_PTR(estate_related(orig_state), rel) {
287 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
288 true_state, false_state);
289 } END_FOR_EACH_PTR(rel);
290 }
291
292 static void set_extra_chunk_true_false(struct expression *expr,
293 struct smatch_state *true_state,
294 struct smatch_state *false_state)
295 {
296 struct var_sym_list *vsl;
297 struct var_sym *vs;
298 struct symbol *type;
299 char *name;
300 struct symbol *sym;
301
302 if (in_warn_on_macro())
303 return;
304
305 type = get_type(expr);
306 if (!type)
307 return;
308
309 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
310 if (!name || !vsl)
311 goto free;
312 FOR_EACH_PTR(vsl, vs) {
313 store_link(link_id, vs->var, vs->sym, name, sym);
314 } END_FOR_EACH_PTR(vs);
315
316 set_true_false_states(SMATCH_EXTRA, name, sym,
317 clone_estate(true_state),
318 clone_estate(false_state));
319 free:
320 free_string(name);
321 }
322
323 static void set_extra_expr_true_false(struct expression *expr,
324 struct smatch_state *true_state,
325 struct smatch_state *false_state)
326 {
327 char *name;
328 struct symbol *sym;
329 sval_t sval;
330
331 if (get_value(expr, &sval))
332 return;
333
334 expr = strip_expr(expr);
335 name = expr_to_var_sym(expr, &sym);
336 if (!name || !sym) {
337 free_string(name);
338 set_extra_chunk_true_false(expr, true_state, false_state);
339 return;
340 }
341 set_extra_true_false(name, sym, true_state, false_state);
342 free_string(name);
343 }
344
345 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
346 {
347 struct expression *iter_var;
348 struct expression *condition;
349 struct sm_state *sm;
350 struct smatch_state *estate;
351 sval_t start;
352
353 condition = strip_expr(loop->iterator_pre_condition);
354 if (!condition)
355 return NULL;
356 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
357 return NULL;
358 if (condition->op != SPECIAL_DECREMENT)
359 return NULL;
360
361 iter_var = condition->unop;
362 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
363 if (!sm)
364 return NULL;
365 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
366 return NULL;
367 start = estate_max(sm->state);
368 if (sval_cmp_val(start, 0) <= 0)
369 return NULL;
370 if (!sval_is_max(start))
371 start.value--;
372
373 if (condition->type == EXPR_PREOP) {
374 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
375 if (estate_has_hard_max(sm->state))
376 estate_set_hard_max(estate);
377 estate_copy_fuzzy_max(estate, sm->state);
378 set_extra_expr_mod(iter_var, estate);
379 }
380 if (condition->type == EXPR_POSTOP) {
381 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
382 if (estate_has_hard_max(sm->state))
383 estate_set_hard_max(estate);
384 estate_copy_fuzzy_max(estate, sm->state);
385 set_extra_expr_mod(iter_var, estate);
386 }
387 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
388 }
389
390 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
391 struct expression *condition)
392 {
393 struct expression *iter_var;
394 struct sm_state *sm;
395 struct smatch_state *estate;
396 sval_t start, end, max;
397
398 iter_var = iter_expr->unop;
399 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
400 if (!sm)
401 return NULL;
402 if (!estate_get_single_value(sm->state, &start))
403 return NULL;
404 if (get_implied_max(condition->right, &end))
405 end = sval_cast(get_type(iter_var), end);
406 else
407 end = sval_type_max(get_type(iter_var));
408
409 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
410 return NULL;
411
412 switch (condition->op) {
413 case SPECIAL_UNSIGNED_LT:
414 case SPECIAL_NOTEQUAL:
415 case '<':
416 if (!sval_is_min(end))
417 end.value--;
418 break;
419 case SPECIAL_UNSIGNED_LTE:
420 case SPECIAL_LTE:
421 break;
422 default:
423 return NULL;
424 }
425 if (sval_cmp(end, start) < 0)
426 return NULL;
427 estate = alloc_estate_range(start, end);
428 if (get_hard_max(condition->right, &max)) {
429 estate_set_hard_max(estate);
430 if (condition->op == '<' ||
431 condition->op == SPECIAL_UNSIGNED_LT ||
432 condition->op == SPECIAL_NOTEQUAL)
433 max.value--;
434 estate_set_fuzzy_max(estate, max);
435 }
436 set_extra_expr_mod(iter_var, estate);
437 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
438 }
439
440 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
441 struct expression *condition)
442 {
443 struct expression *iter_var;
444 struct sm_state *sm;
445 struct smatch_state *estate;
446 sval_t start, end;
447
448 iter_var = iter_expr->unop;
449 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
450 if (!sm)
451 return NULL;
452 if (!estate_get_single_value(sm->state, &start))
453 return NULL;
454 if (!get_implied_min(condition->right, &end))
455 end = sval_type_min(get_type(iter_var));
456 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
457 return NULL;
458
459 switch (condition->op) {
460 case SPECIAL_NOTEQUAL:
461 case '>':
462 if (!sval_is_min(end) && !sval_is_max(end))
463 end.value++;
464 break;
465 case SPECIAL_GTE:
466 break;
467 default:
468 return NULL;
469 }
470 if (sval_cmp(end, start) > 0)
471 return NULL;
472 estate = alloc_estate_range(end, start);
473 estate_set_hard_max(estate);
474 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
475 set_extra_expr_mod(iter_var, estate);
476 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
477 }
478
479 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
480 {
481 struct expression *iter_expr;
482 struct expression *condition;
483
484 if (!loop->iterator_post_statement)
485 return NULL;
486 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
487 return NULL;
488 iter_expr = loop->iterator_post_statement->expression;
489 if (!loop->iterator_pre_condition)
490 return NULL;
491 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
492 return NULL;
493 condition = loop->iterator_pre_condition;
494
495 if (iter_expr->op == SPECIAL_INCREMENT)
496 return handle_canonical_for_inc(iter_expr, condition);
497 if (iter_expr->op == SPECIAL_DECREMENT)
498 return handle_canonical_for_dec(iter_expr, condition);
499 return NULL;
500 }
501
502 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
503 {
504 struct sm_state *ret;
505
506 __push_fake_cur_stree();
507 if (!loop->iterator_post_statement)
508 ret = handle_canonical_while_count_down(loop);
509 else
510 ret = handle_canonical_for_loops(loop);
511 *stree = __pop_fake_cur_stree();
512 return ret;
513 }
514
515 int __iterator_unchanged(struct sm_state *sm)
516 {
517 if (!sm)
518 return 0;
519 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
520 return 1;
521 return 0;
522 }
523
524 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
525 {
526 sval_t after_value;
527
528 /* paranoid checking. prolly not needed */
529 condition = strip_expr(condition);
530 if (!condition)
531 return;
532 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
533 return;
534 if (condition->op != SPECIAL_DECREMENT)
535 return;
536 after_value = estate_min(sm->state);
537 after_value.value--;
538 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
539 }
540
541 void __extra_pre_loop_hook_after(struct sm_state *sm,
542 struct statement *iterator,
543 struct expression *condition)
544 {
545 struct expression *iter_expr;
546 sval_t limit;
547 struct smatch_state *state;
548
549 if (!iterator) {
550 while_count_down_after(sm, condition);
551 return;
552 }
553
554 iter_expr = iterator->expression;
555
556 if (condition->type != EXPR_COMPARE)
557 return;
558 if (iter_expr->op == SPECIAL_INCREMENT) {
559 limit = sval_binop(estate_max(sm->state), '+',
560 sval_type_val(estate_type(sm->state), 1));
561 } else {
562 limit = sval_binop(estate_min(sm->state), '-',
563 sval_type_val(estate_type(sm->state), 1));
564 }
565 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
566 if (iter_expr->op == SPECIAL_INCREMENT)
567 state = alloc_estate_range(estate_min(sm->state), limit);
568 else
569 state = alloc_estate_range(limit, estate_max(sm->state));
570 } else {
571 state = alloc_estate_sval(limit);
572 }
573 if (!estate_has_hard_max(sm->state)) {
574 estate_clear_hard_max(state);
575 }
576 if (estate_has_fuzzy_max(sm->state)) {
577 sval_t hmax = estate_get_fuzzy_max(sm->state);
578 sval_t max = estate_max(sm->state);
579
580 if (sval_cmp(hmax, max) != 0)
581 estate_clear_fuzzy_max(state);
582 } else if (!estate_has_fuzzy_max(sm->state)) {
583 estate_clear_fuzzy_max(state);
584 }
585
586 set_extra_mod(sm->name, sm->sym, state);
587 }
588
589 static struct stree *unmatched_stree;
590 static struct smatch_state *unmatched_state(struct sm_state *sm)
591 {
592 struct smatch_state *state;
593
594 if (unmatched_stree) {
595 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
596 if (state)
597 return state;
598 }
599 if (parent_is_gone_var_sym(sm->name, sm->sym))
600 return alloc_estate_empty();
601 return alloc_estate_whole(estate_type(sm->state));
602 }
603
604 static void clear_the_pointed_at(struct expression *expr)
605 {
606 struct stree *stree;
607 char *name;
608 struct symbol *sym;
609 struct sm_state *tmp;
610
611 name = expr_to_var_sym(expr, &sym);
612 if (!name || !sym)
613 goto free;
614
615 stree = __get_cur_stree();
616 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
617 if (tmp->name[0] != '*')
618 continue;
619 if (tmp->sym != sym)
620 continue;
621 if (strcmp(tmp->name + 1, name) != 0)
622 continue;
623 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
624 } END_FOR_EACH_SM(tmp);
625
626 free:
627 free_string(name);
628 }
629
630 static void match_function_call(struct expression *expr)
631 {
632 struct expression *arg;
633 struct expression *tmp;
634
635 /* if we have the db this is handled in smatch_function_hooks.c */
636 if (!option_no_db)
637 return;
638 if (inlinable(expr->fn))
639 return;
640
641 FOR_EACH_PTR(expr->args, arg) {
642 tmp = strip_expr(arg);
643 if (tmp->type == EXPR_PREOP && tmp->op == '&')
644 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
645 else
646 clear_the_pointed_at(tmp);
647 } END_FOR_EACH_PTR(arg);
648 }
649
650 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
651 {
652 if (!one || !two)
653 return 0;
654 if (one->type == SYM_PTR && two->type == SYM_PTR)
655 return 1;
656 return types_equiv(one, two);
657 }
658
659 static void save_chunk_info(struct expression *left, struct expression *right)
660 {
661 struct var_sym_list *vsl;
662 struct var_sym *vs;
663 struct expression *add_expr;
664 struct symbol *type;
665 sval_t sval;
666 char *name;
667 struct symbol *sym;
668
669 if (right->type != EXPR_BINOP || right->op != '-')
670 return;
671 if (!get_value(right->left, &sval))
672 return;
673 if (!expr_to_sym(right->right))
674 return;
675
676 add_expr = binop_expression(left, '+', right->right);
677 type = get_type(add_expr);
678 if (!type)
679 return;
680 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
681 if (!name || !vsl)
682 goto free;
683 FOR_EACH_PTR(vsl, vs) {
684 store_link(link_id, vs->var, vs->sym, name, sym);
685 } END_FOR_EACH_PTR(vs);
686
687 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
688 free:
689 free_string(name);
690 }
691
692 static void do_array_assign(struct expression *left, int op, struct expression *right)
693 {
694 struct range_list *rl;
695
696 if (op == '=') {
697 get_absolute_rl(right, &rl);
698 rl = cast_rl(get_type(left), rl);
699 } else {
700 rl = alloc_whole_rl(get_type(left));
701 }
702
703 set_extra_array_mod(left, alloc_estate_rl(rl));
704 }
705
706 static void match_untracked_array(struct expression *call, int param)
707 {
708 struct expression *arg;
709
710 arg = get_argument_from_call_expr(call->args, param);
711 arg = strip_expr(arg);
712
713 clear_array_states(arg);
714 }
715
716 static void match_vanilla_assign(struct expression *left, struct expression *right)
717 {
718 struct range_list *rl = NULL;
719 struct symbol *right_sym;
720 struct symbol *left_type;
721 struct symbol *right_type;
722 char *right_name = NULL;
723 struct symbol *sym;
724 char *name;
725 sval_t max;
726 struct smatch_state *state;
727
728 if (is_struct(left))
729 return;
730
731 save_chunk_info(left, right);
732
733 name = expr_to_var_sym(left, &sym);
734 if (!name) {
735 if (is_array(left))
736 do_array_assign(left, '=', right);
737 return;
738 }
739
740 left_type = get_type(left);
741 right_type = get_type(right);
742
743 right_name = expr_to_var_sym(right, &right_sym);
744
745 if (!__in_fake_assign &&
746 !(right->type == EXPR_PREOP && right->op == '&') &&
747 right_name && right_sym &&
748 types_equiv_or_pointer(left_type, right_type) &&
749 !has_symbol(right, sym)) {
750 set_equiv(left, right);
751 goto free;
752 }
753
754 if (is_pointer(right) && get_address_rl(right, &rl)) {
755 state = alloc_estate_rl(rl);
756 } else if (get_implied_rl(right, &rl)) {
757 rl = cast_rl(left_type, rl);
758 state = alloc_estate_rl(rl);
759 if (get_hard_max(right, &max)) {
760 estate_set_hard_max(state);
761 estate_set_fuzzy_max(state, max);
762 }
763 } else {
764 rl = alloc_whole_rl(right_type);
765 rl = cast_rl(left_type, rl);
766 state = alloc_estate_rl(rl);
767 }
768 set_extra_mod(name, sym, state);
769 free:
770 free_string(right_name);
771 }
772
773 static int op_remove_assign(int op)
774 {
775 switch (op) {
776 case SPECIAL_ADD_ASSIGN:
777 return '+';
778 case SPECIAL_SUB_ASSIGN:
779 return '-';
780 case SPECIAL_MUL_ASSIGN:
781 return '*';
782 case SPECIAL_DIV_ASSIGN:
783 return '/';
784 case SPECIAL_MOD_ASSIGN:
785 return '%';
786 case SPECIAL_AND_ASSIGN:
787 return '&';
788 case SPECIAL_OR_ASSIGN:
789 return '|';
790 case SPECIAL_XOR_ASSIGN:
791 return '^';
792 case SPECIAL_SHL_ASSIGN:
793 return SPECIAL_LEFTSHIFT;
794 case SPECIAL_SHR_ASSIGN:
795 return SPECIAL_RIGHTSHIFT;
796 default:
797 return op;
798 }
799 }
800
801 static void match_assign(struct expression *expr)
802 {
803 struct range_list *rl = NULL;
804 struct expression *left;
805 struct expression *right;
806 struct expression *binop_expr;
807 struct symbol *left_type;
808 struct symbol *right_type;
809 struct symbol *sym;
810 char *name;
811 sval_t left_min, left_max;
812 sval_t right_min, right_max;
813 sval_t res_min, res_max;
814
815 left = strip_expr(expr->left);
816
817 right = strip_parens(expr->right);
818 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
819 right = strip_parens(right->left);
820
821 if (expr->op == '=' && is_condition(expr->right))
822 return; /* handled in smatch_condition.c */
823 if (expr->op == '=' && right->type == EXPR_CALL)
824 return; /* handled in smatch_function_hooks.c */
825 if (expr->op == '=') {
826 match_vanilla_assign(left, right);
827 return;
828 }
829
830 name = expr_to_var_sym(left, &sym);
831 if (!name)
832 return;
833
834 left_type = get_type(left);
835 right_type = get_type(right);
836
837 res_min = sval_type_min(left_type);
838 res_max = sval_type_max(left_type);
839
840 switch (expr->op) {
841 case SPECIAL_ADD_ASSIGN:
842 get_absolute_max(left, &left_max);
843 get_absolute_max(right, &right_max);
844 if (sval_binop_overflows(left_max, '+', right_max))
845 break;
846 if (get_implied_min(left, &left_min) &&
847 !sval_is_negative_min(left_min) &&
848 get_implied_min(right, &right_min) &&
849 !sval_is_negative_min(right_min)) {
850 res_min = sval_binop(left_min, '+', right_min);
851 res_min = sval_cast(right_type, res_min);
852 }
853 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
854 break;
855 res_max = sval_binop(left_max, '+', right_max);
856 res_max = sval_cast(right_type, res_max);
857 break;
858 case SPECIAL_SUB_ASSIGN:
859 if (get_implied_max(left, &left_max) &&
860 !sval_is_max(left_max) &&
861 get_implied_min(right, &right_min) &&
862 !sval_is_min(right_min)) {
863 res_max = sval_binop(left_max, '-', right_min);
864 res_max = sval_cast(right_type, res_max);
865 }
866 if (inside_loop())
867 break;
868 if (get_implied_min(left, &left_min) &&
869 !sval_is_min(left_min) &&
870 get_implied_max(right, &right_max) &&
871 !sval_is_max(right_max)) {
872 res_min = sval_binop(left_min, '-', right_max);
873 res_min = sval_cast(right_type, res_min);
874 }
875 break;
876 case SPECIAL_AND_ASSIGN:
877 case SPECIAL_MOD_ASSIGN:
878 case SPECIAL_SHL_ASSIGN:
879 case SPECIAL_SHR_ASSIGN:
880 case SPECIAL_OR_ASSIGN:
881 case SPECIAL_XOR_ASSIGN:
882 case SPECIAL_MUL_ASSIGN:
883 case SPECIAL_DIV_ASSIGN:
884 binop_expr = binop_expression(expr->left,
885 op_remove_assign(expr->op),
886 expr->right);
887 if (get_absolute_rl(binop_expr, &rl)) {
888 rl = cast_rl(left_type, rl);
889 set_extra_mod(name, sym, alloc_estate_rl(rl));
890 goto free;
891 }
892 break;
893 }
894 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
895 set_extra_mod(name, sym, alloc_estate_rl(rl));
896 free:
897 free_string(name);
898 }
899
900 static struct smatch_state *increment_state(struct smatch_state *state)
901 {
902 sval_t min = estate_min(state);
903 sval_t max = estate_max(state);
904
905 if (!estate_rl(state))
906 return NULL;
907
908 if (inside_loop())
909 max = sval_type_max(max.type);
910
911 if (!sval_is_min(min) && !sval_is_max(min))
912 min.value++;
913 if (!sval_is_min(max) && !sval_is_max(max))
914 max.value++;
915 return alloc_estate_range(min, max);
916 }
917
918 static struct smatch_state *decrement_state(struct smatch_state *state)
919 {
920 sval_t min = estate_min(state);
921 sval_t max = estate_max(state);
922
923 if (!estate_rl(state))
924 return NULL;
925
926 if (inside_loop())
927 min = sval_type_min(min.type);
928
929 if (!sval_is_min(min) && !sval_is_max(min))
930 min.value--;
931 if (!sval_is_min(max) && !sval_is_max(max))
932 max.value--;
933 return alloc_estate_range(min, max);
934 }
935
936 static void unop_expr(struct expression *expr)
937 {
938 struct smatch_state *state;
939
940 if (expr->smatch_flags & Handled)
941 return;
942
943 switch (expr->op) {
944 case SPECIAL_INCREMENT:
945 state = get_state_expr(SMATCH_EXTRA, expr->unop);
946 state = increment_state(state);
947 if (!state)
948 state = alloc_estate_whole(get_type(expr));
949 set_extra_expr_mod(expr->unop, state);
950 break;
951 case SPECIAL_DECREMENT:
952 state = get_state_expr(SMATCH_EXTRA, expr->unop);
953 state = decrement_state(state);
954 if (!state)
955 state = alloc_estate_whole(get_type(expr));
956 set_extra_expr_mod(expr->unop, state);
957 break;
958 default:
959 return;
960 }
961 }
962
963 static void asm_expr(struct statement *stmt)
964 {
965
966 struct expression *expr;
967 struct symbol *type;
968 int state = 0;
969
970 FOR_EACH_PTR(stmt->asm_outputs, expr) {
971 switch (state) {
972 case 0: /* identifier */
973 case 1: /* constraint */
974 state++;
975 continue;
976 case 2: /* expression */
977 state = 0;
978 type = get_type(strip_expr(expr));
979 set_extra_expr_mod(expr, alloc_estate_whole(type));
980 continue;
981 }
982 } END_FOR_EACH_PTR(expr);
983 }
984
985 static void check_dereference(struct expression *expr)
986 {
987 if (outside_of_function())
988 return;
989 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
990 }
991
992 static void match_dereferences(struct expression *expr)
993 {
994 if (expr->type != EXPR_PREOP)
995 return;
996 check_dereference(expr->unop);
997 }
998
999 static void match_pointer_as_array(struct expression *expr)
1000 {
1001 if (!is_array(expr))
1002 return;
1003 check_dereference(get_array_base(expr));
1004 }
1005
1006 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
1007 {
1008 struct symbol *sym;
1009 char *name;
1010
1011 name = get_variable_from_key(arg, key, &sym);
1012 if (!name || !sym)
1013 goto free;
1014
1015 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1016
1017 free:
1018 free_string(name);
1019 }
1020
1021 static sval_t add_one(sval_t sval)
1022 {
1023 sval.value++;
1024 return sval;
1025 }
1026
1027 static sval_t sub_one(sval_t sval)
1028 {
1029 sval.value--;
1030 return sval;
1031 }
1032
1033 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1034 {
1035 struct range_list *left_orig;
1036 struct range_list *left_true;
1037 struct range_list *left_false;
1038 struct range_list *right_orig;
1039 struct range_list *right_true;
1040 struct range_list *right_false;
1041 struct smatch_state *left_true_state;
1042 struct smatch_state *left_false_state;
1043 struct smatch_state *right_true_state;
1044 struct smatch_state *right_false_state;
1045 sval_t min, max, dummy, hard_max;
1046 int left_postop = 0;
1047 int right_postop = 0;
1048
1049 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1050 if (left->type == EXPR_POSTOP) {
1051 left->smatch_flags |= Handled;
1052 left_postop = left->op;
1053 }
1054 left = strip_expr(left->unop);
1055 }
1056 while (left->type == EXPR_ASSIGNMENT)
1057 left = strip_expr(left->left);
1058
1059 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1060 if (right->type == EXPR_POSTOP) {
1061 right->smatch_flags |= Handled;
1062 right_postop = right->op;
1063 }
1064 right = strip_expr(right->unop);
1065 }
1066
1067 if (get_implied_rl(left, &left_orig)) {
1068 left_orig = cast_rl(type, left_orig);
1069 } else {
1070 min = sval_type_min(get_type(left));
1071 max = sval_type_max(get_type(left));
1072 left_orig = cast_rl(type, alloc_rl(min, max));
1073 }
1074
1075 if (get_implied_rl(right, &right_orig)) {
1076 right_orig = cast_rl(type, right_orig);
1077 } else {
1078 min = sval_type_min(get_type(right));
1079 max = sval_type_max(get_type(right));
1080 right_orig = cast_rl(type, alloc_rl(min, max));
1081 }
1082 min = sval_type_min(type);
1083 max = sval_type_max(type);
1084
1085 left_true = clone_rl(left_orig);
1086 left_false = clone_rl(left_orig);
1087 right_true = clone_rl(right_orig);
1088 right_false = clone_rl(right_orig);
1089
1090 switch (op) {
1091 case '<':
1092 case SPECIAL_UNSIGNED_LT:
1093 left_true = remove_range(left_orig, rl_max(right_orig), max);
1094 if (!sval_is_min(rl_min(right_orig))) {
1095 left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1096 }
1097
1098 right_true = remove_range(right_orig, min, rl_min(left_orig));
1099 if (!sval_is_max(rl_max(left_orig)))
1100 right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1101 break;
1102 case SPECIAL_UNSIGNED_LTE:
1103 case SPECIAL_LTE:
1104 if (!sval_is_max(rl_max(right_orig)))
1105 left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1106 left_false = remove_range(left_orig, min, rl_min(right_orig));
1107
1108 if (!sval_is_min(rl_min(left_orig)))
1109 right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1110 right_false = remove_range(right_orig, rl_max(left_orig), max);
1111
1112 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1113 left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
1114 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1115 right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
1116 break;
1117 case SPECIAL_EQUAL:
1118 if (!sval_is_max(rl_max(right_orig))) {
1119 left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
1120 }
1121 if (!sval_is_min(rl_min(right_orig))) {
1122 left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
1123 }
1124 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1125 left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1126
1127 if (!sval_is_max(rl_max(left_orig)))
1128 right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
1129 if (!sval_is_min(rl_min(left_orig)))
1130 right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
1131 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1132 right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1133 break;
1134 case SPECIAL_UNSIGNED_GTE:
1135 case SPECIAL_GTE:
1136 if (!sval_is_min(rl_min(right_orig)))
1137 left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1138 left_false = remove_range(left_orig, rl_max(right_orig), max);
1139
1140 if (!sval_is_max(rl_max(left_orig)))
1141 right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1142 right_false = remove_range(right_orig, min, rl_min(left_orig));
1143
1144 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1145 right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
1146 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1147 left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
1148 break;
1149 case '>':
1150 case SPECIAL_UNSIGNED_GT:
1151 left_true = remove_range(left_orig, min, rl_min(right_orig));
1152 if (!sval_is_max(rl_max(right_orig)))
1153 left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1154
1155 right_true = remove_range(right_orig, rl_max(left_orig), max);
1156 if (!sval_is_min(rl_min(left_orig)))
1157 right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1158 break;
1159 case SPECIAL_NOTEQUAL:
1160 if (!sval_is_max(rl_max(right_orig)))
1161 left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
1162 if (!sval_is_min(rl_min(right_orig)))
1163 left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
1164 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1165 left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1166
1167 if (!sval_is_max(rl_max(left_orig)))
1168 right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
1169 if (!sval_is_min(rl_min(left_orig)))
1170 right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
1171 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1172 right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1173 break;
1174 default:
1175 return;
1176 }
1177
1178 left_true = rl_truncate_cast(get_type(left), left_true);
1179 left_false = rl_truncate_cast(get_type(left), left_false);
1180 right_true = rl_truncate_cast(get_type(right), right_true);
1181 right_false = rl_truncate_cast(get_type(right), right_false);
1182
1183 left_true_state = alloc_estate_rl(left_true);
1184 left_false_state = alloc_estate_rl(left_false);
1185 right_true_state = alloc_estate_rl(right_true);
1186 right_false_state = alloc_estate_rl(right_false);
1187
1188 switch (op) {
1189 case '<':
1190 case SPECIAL_UNSIGNED_LT:
1191 case SPECIAL_UNSIGNED_LTE:
1192 case SPECIAL_LTE:
1193 if (get_hard_max(right, &dummy))
1194 estate_set_hard_max(left_true_state);
1195 if (get_hard_max(left, &dummy))
1196 estate_set_hard_max(right_false_state);
1197 break;
1198 case '>':
1199 case SPECIAL_UNSIGNED_GT:
1200 case SPECIAL_UNSIGNED_GTE:
1201 case SPECIAL_GTE:
1202 if (get_hard_max(left, &dummy))
1203 estate_set_hard_max(right_true_state);
1204 if (get_hard_max(right, &dummy))
1205 estate_set_hard_max(left_false_state);
1206 break;
1207 }
1208
1209 switch (op) {
1210 case '<':
1211 case SPECIAL_UNSIGNED_LT:
1212 case SPECIAL_UNSIGNED_LTE:
1213 case SPECIAL_LTE:
1214 if (get_hard_max(right, &hard_max)) {
1215 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1216 hard_max.value--;
1217 estate_set_fuzzy_max(left_true_state, hard_max);
1218 }
1219 if (get_implied_value(right, &hard_max)) {
1220 if (op == SPECIAL_UNSIGNED_LTE ||
1221 op == SPECIAL_LTE)
1222 hard_max.value++;
1223 estate_set_fuzzy_max(left_false_state, hard_max);
1224 }
1225 if (get_hard_max(left, &hard_max)) {
1226 if (op == SPECIAL_UNSIGNED_LTE ||
1227 op == SPECIAL_LTE)
1228 hard_max.value--;
1229 estate_set_fuzzy_max(right_false_state, hard_max);
1230 }
1231 if (get_implied_value(left, &hard_max)) {
1232 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1233 hard_max.value++;
1234 estate_set_fuzzy_max(right_true_state, hard_max);
1235 }
1236 break;
1237 case '>':
1238 case SPECIAL_UNSIGNED_GT:
1239 case SPECIAL_UNSIGNED_GTE:
1240 case SPECIAL_GTE:
1241 if (get_hard_max(left, &hard_max)) {
1242 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1243 hard_max.value--;
1244 estate_set_fuzzy_max(right_true_state, hard_max);
1245 }
1246 if (get_implied_value(left, &hard_max)) {
1247 if (op == SPECIAL_UNSIGNED_GTE ||
1248 op == SPECIAL_GTE)
1249 hard_max.value++;
1250 estate_set_fuzzy_max(right_false_state, hard_max);
1251 }
1252 if (get_hard_max(right, &hard_max)) {
1253 if (op == SPECIAL_UNSIGNED_LTE ||
1254 op == SPECIAL_LTE)
1255 hard_max.value--;
1256 estate_set_fuzzy_max(left_false_state, hard_max);
1257 }
1258 if (get_implied_value(right, &hard_max)) {
1259 if (op == '>' ||
1260 op == SPECIAL_UNSIGNED_GT)
1261 hard_max.value++;
1262 estate_set_fuzzy_max(left_true_state, hard_max);
1263 }
1264 break;
1265 case SPECIAL_EQUAL:
1266 if (get_hard_max(left, &hard_max))
1267 estate_set_fuzzy_max(right_true_state, hard_max);
1268 if (get_hard_max(right, &hard_max))
1269 estate_set_fuzzy_max(left_true_state, hard_max);
1270 break;
1271 }
1272
1273 if (get_hard_max(left, &hard_max)) {
1274 estate_set_hard_max(left_true_state);
1275 estate_set_hard_max(left_false_state);
1276 }
1277 if (get_hard_max(right, &hard_max)) {
1278 estate_set_hard_max(right_true_state);
1279 estate_set_hard_max(right_false_state);
1280 }
1281
1282 if (left_postop == SPECIAL_INCREMENT) {
1283 left_true_state = increment_state(left_true_state);
1284 left_false_state = increment_state(left_false_state);
1285 }
1286 if (left_postop == SPECIAL_DECREMENT) {
1287 left_true_state = decrement_state(left_true_state);
1288 left_false_state = decrement_state(left_false_state);
1289 }
1290 if (right_postop == SPECIAL_INCREMENT) {
1291 right_true_state = increment_state(right_true_state);
1292 right_false_state = increment_state(right_false_state);
1293 }
1294 if (right_postop == SPECIAL_DECREMENT) {
1295 right_true_state = decrement_state(right_true_state);
1296 right_false_state = decrement_state(right_false_state);
1297 }
1298
1299 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1300 left_true_state = NULL;
1301 left_false_state = NULL;
1302 }
1303
1304 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1305 right_true_state = NULL;
1306 right_false_state = NULL;
1307 }
1308
1309 set_extra_expr_true_false(left, left_true_state, left_false_state);
1310 set_extra_expr_true_false(right, right_true_state, right_false_state);
1311 }
1312
1313 static int is_simple_math(struct expression *expr)
1314 {
1315 if (!expr)
1316 return 0;
1317 if (expr->type != EXPR_BINOP)
1318 return 0;
1319 switch (expr->op) {
1320 case '+':
1321 case '-':
1322 case '*':
1323 return 1;
1324 }
1325 return 0;
1326 }
1327
1328 static void move_known_values(struct expression **left_p, struct expression **right_p)
1329 {
1330 struct expression *left = *left_p;
1331 struct expression *right = *right_p;
1332 sval_t sval;
1333
1334 if (get_implied_value(left, &sval)) {
1335 if (!is_simple_math(right))
1336 return;
1337 if (right->op == '*') {
1338 sval_t divisor;
1339
1340 if (!get_value(right->right, &divisor))
1341 return;
1342 if (divisor.value == 0 && sval.value % divisor.value)
1343 return;
1344 *left_p = binop_expression(left, invert_op(right->op), right->right);
1345 *right_p = right->left;
1346 return;
1347 }
1348 if (right->op == '+' && get_value(right->left, &sval)) {
1349 *left_p = binop_expression(left, invert_op(right->op), right->left);
1350 *right_p = right->right;
1351 return;
1352 }
1353 if (get_value(right->right, &sval)) {
1354 *left_p = binop_expression(left, invert_op(right->op), right->right);
1355 *right_p = right->left;
1356 return;
1357 }
1358 return;
1359 }
1360 if (get_implied_value(right, &sval)) {
1361 if (!is_simple_math(left))
1362 return;
1363 if (left->op == '*') {
1364 sval_t divisor;
1365
1366 if (!get_value(left->right, &divisor))
1367 return;
1368 if (divisor.value == 0 && sval.value % divisor.value)
1369 return;
1370 *right_p = binop_expression(right, invert_op(left->op), left->right);
1371 *left_p = left->left;
1372 return;
1373 }
1374 if (left->op == '+' && get_value(left->left, &sval)) {
1375 *right_p = binop_expression(right, invert_op(left->op), left->left);
1376 *left_p = left->right;
1377 return;
1378 }
1379
1380 if (get_value(left->right, &sval)) {
1381 *right_p = binop_expression(right, invert_op(left->op), left->right);
1382 *left_p = left->left;
1383 return;
1384 }
1385 return;
1386 }
1387 }
1388
1389 static int match_func_comparison(struct expression *expr)
1390 {
1391 struct expression *left = strip_expr(expr->left);
1392 struct expression *right = strip_expr(expr->right);
1393 sval_t sval;
1394
1395 /*
1396 * fixme: think about this harder. We should always be trying to limit
1397 * the non-call side as well. If we can't determine the limitter does
1398 * that mean we aren't querying the database and are missing important
1399 * information?
1400 */
1401
1402 if (left->type == EXPR_CALL) {
1403 if (get_implied_value(left, &sval)) {
1404 handle_comparison(get_type(expr), left, expr->op, right);
1405 return 1;
1406 }
1407 function_comparison(left, expr->op, right);
1408 return 1;
1409 }
1410
1411 if (right->type == EXPR_CALL) {
1412 if (get_implied_value(right, &sval)) {
1413 handle_comparison(get_type(expr), left, expr->op, right);
1414 return 1;
1415 }
1416 function_comparison(left, expr->op, right);
1417 return 1;
1418 }
1419
1420 return 0;
1421 }
1422
1423 static void match_comparison(struct expression *expr)
1424 {
1425 struct expression *left_orig = strip_expr(expr->left);
1426 struct expression *right_orig = strip_expr(expr->right);
1427 struct expression *left, *right;
1428 struct expression *prev;
1429 struct symbol *type;
1430
1431 if (match_func_comparison(expr))
1432 return;
1433
1434 type = get_type(expr);
1435 if (!type)
1436 type = &llong_ctype;
1437
1438 left = left_orig;
1439 right = right_orig;
1440 move_known_values(&left, &right);
1441 handle_comparison(type, left, expr->op, right);
1442
1443 prev = get_assigned_expr(left_orig);
1444 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1445 left = prev;
1446 right = right_orig;
1447 move_known_values(&left, &right);
1448 handle_comparison(type, left, expr->op, right);
1449 }
1450
1451 prev = get_assigned_expr(right_orig);
1452 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1453 left = left_orig;
1454 right = prev;
1455 move_known_values(&left, &right);
1456 handle_comparison(type, left, expr->op, right);
1457 }
1458 }
1459
1460 static void handle_AND_condition(struct expression *expr)
1461 {
1462 struct range_list *rl = NULL;
1463 sval_t known;
1464
1465 if (get_implied_value(expr->left, &known) && known.value > 0) {
1466 known.value--;
1467 get_absolute_rl(expr->right, &rl);
1468 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1469 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1470 return;
1471 }
1472
1473 if (get_implied_value(expr->right, &known) && known.value > 0) {
1474 known.value--;
1475 get_absolute_rl(expr->left, &rl);
1476 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1477 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1478 return;
1479 }
1480 }
1481
1482 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1483 void __extra_match_condition(struct expression *expr)
1484 {
1485 struct smatch_state *pre_state;
1486 struct smatch_state *true_state;
1487 struct smatch_state *false_state;
1488
1489 expr = strip_expr(expr);
1490 switch (expr->type) {
1491 case EXPR_CALL:
1492 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1493 return;
1494 case EXPR_PREOP:
1495 case EXPR_SYMBOL:
1496 case EXPR_DEREF: {
1497 sval_t zero;
1498
1499 zero = sval_blank(expr);
1500 zero.value = 0;
1501
1502 pre_state = get_extra_state(expr);
1503 true_state = estate_filter_sval(pre_state, zero);
1504 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1505 false_state = alloc_estate_sval(zero);
1506 else
1507 false_state = alloc_estate_empty();
1508 set_extra_expr_true_false(expr, true_state, false_state);
1509 return;
1510 }
1511 case EXPR_COMPARE:
1512 match_comparison(expr);
1513 return;
1514 case EXPR_ASSIGNMENT:
1515 __extra_match_condition(expr->left);
1516 return;
1517 case EXPR_BINOP:
1518 if (expr->op == '&')
1519 handle_AND_condition(expr);
1520 return;
1521 }
1522 }
1523
1524 static void assume_indexes_are_valid(struct expression *expr)
1525 {
1526 struct expression *array_expr;
1527 int array_size;
1528 struct expression *offset;
1529 struct symbol *offset_type;
1530 struct range_list *rl_before;
1531 struct range_list *rl_after;
1532 struct range_list *filter = NULL;
1533 sval_t size;
1534
1535 expr = strip_expr(expr);
1536 if (!is_array(expr))
1537 return;
1538
1539 offset = get_array_offset(expr);
1540 offset_type = get_type(offset);
1541 if (offset_type && type_signed(offset_type)) {
1542 filter = alloc_rl(sval_type_min(offset_type),
1543 sval_type_val(offset_type, -1));
1544 }
1545
1546 array_expr = get_array_base(expr);
1547 array_size = get_real_array_size(array_expr);
1548 if (array_size > 1) {
1549 size = sval_type_val(offset_type, array_size);
1550 add_range(&filter, size, sval_type_max(offset_type));
1551 }
1552
1553 if (!filter)
1554 return;
1555 get_absolute_rl(offset, &rl_before);
1556 rl_after = rl_filter(rl_before, filter);
1557 if (rl_equiv(rl_before, rl_after))
1558 return;
1559 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1560 }
1561
1562 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1563 int implied_not_equal(struct expression *expr, long long val)
1564 {
1565 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1566 }
1567
1568 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1569 {
1570 struct smatch_state *estate;
1571
1572 estate = get_state(SMATCH_EXTRA, name, sym);
1573 if (!estate)
1574 return 0;
1575 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1576 return 1;
1577 return 0;
1578 }
1579
1580 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1581 {
1582 char buf[256];
1583 char *start;
1584 char *end;
1585 struct smatch_state *state;
1586
1587 strncpy(buf, name, sizeof(buf) - 1);
1588 buf[sizeof(buf) - 1] = '\0';
1589
1590 start = &buf[0];
1591 while (*start == '*') {
1592 start++;
1593 state = get_state(SMATCH_EXTRA, start, sym);
1594 if (!state)
1595 continue;
1596 if (!estate_rl(state))
1597 return 1;
1598 if (estate_min(state).value == 0 &&
1599 estate_max(state).value == 0)
1600 return 1;
1601 }
1602
1603 start = &buf[0];
1604 while (*start == '&')
1605 start++;
1606
1607 while ((end = strrchr(start, '-'))) {
1608 *end = '\0';
1609 state = get_state(SMATCH_EXTRA, start, sym);
1610 if (!state)
1611 continue;
1612 if (estate_min(state).value == 0 &&
1613 estate_max(state).value == 0)
1614 return 1;
1615 }
1616 return 0;
1617 }
1618
1619 int parent_is_null(struct expression *expr)
1620 {
1621 struct symbol *sym;
1622 char *var;
1623 int ret = 0;
1624
1625 expr = strip_expr(expr);
1626 var = expr_to_var_sym(expr, &sym);
1627 if (!var || !sym)
1628 goto free;
1629 ret = parent_is_null_var_sym(var, sym);
1630 free:
1631 free_string(var);
1632 return ret;
1633 }
1634
1635 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
1636 {
1637 *(int *)found = 1;
1638 return 0;
1639 }
1640
1641 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1642 {
1643 sval_t sval;
1644 int found = 0;
1645
1646 /* for function pointers assume everything is used */
1647 if (call->fn->type != EXPR_SYMBOL)
1648 return 0;
1649
1650 /*
1651 * kzalloc() information is treated as special because so there is just
1652 * a lot of stuff initialized to zero and it makes building the database
1653 * take hours and hours.
1654 *
1655 * In theory, we should just remove this line and not pass any unused
1656 * information, but I'm not sure enough that this code works so I want
1657 * to hold off on that for now.
1658 */
1659 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
1660 return 0;
1661
1662 run_sql(&param_used_callback, &found,
1663 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
1664 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
1665 if (found)
1666 return 0;
1667
1668 /* If the database is not built yet, then assume everything is used */
1669 run_sql(&param_used_callback, &found,
1670 "select * from call_implies where %s and type = %d;",
1671 get_static_filter(call->fn->symbol), PARAM_USED);
1672 if (!found)
1673 return 0;
1674
1675 return 1;
1676 }
1677
1678 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1679 {
1680 if (estate_is_whole(sm->state))
1681 return;
1682 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
1683 return;
1684 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, sm->state->name);
1685 if (estate_has_fuzzy_max(sm->state))
1686 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1687 sval_to_str(estate_get_fuzzy_max(sm->state)));
1688 }
1689
1690 static void db_limited_before(void)
1691 {
1692 unmatched_stree = clone_stree(__get_cur_stree());
1693 }
1694
1695 static void db_limited_after(void)
1696 {
1697 free_stree(&unmatched_stree);
1698 }
1699
1700 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
1701 {
1702 struct expression *arg;
1703 char *name;
1704 struct symbol *sym;
1705 struct sm_state *sm;
1706 struct symbol *compare_type, *var_type;
1707 struct range_list *rl;
1708 struct range_list *limit;
1709 struct range_list *new;
1710
1711 while (expr->type == EXPR_ASSIGNMENT)
1712 expr = strip_expr(expr->right);
1713 if (expr->type != EXPR_CALL)
1714 return;
1715
1716 arg = get_argument_from_call_expr(expr->args, param);
1717 if (!arg)
1718 return;
1719
1720 name = get_variable_from_key(arg, key, &sym);
1721 if (!name || !sym)
1722 goto free;
1723
1724 if (strcmp(key, "$") == 0)
1725 compare_type = get_arg_type(expr->fn, param);
1726 else
1727 compare_type = get_member_type_from_key(arg, key);
1728
1729 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1730 if (sm)
1731 rl = estate_rl(sm->state);
1732 else
1733 rl = alloc_whole_rl(compare_type);
1734
1735 call_results_to_rl(expr, compare_type, value, &limit);
1736 new = rl_intersection(rl, limit);
1737
1738 var_type = get_member_type_from_key(arg, key);
1739 new = cast_rl(var_type, new);
1740
1741 /* We want to preserve the implications here */
1742 if (sm && rl_equiv(estate_rl(sm->state), new))
1743 __set_sm(sm);
1744 else {
1745 if (op == PARAM_LIMIT)
1746 set_extra_nomod(name, sym, alloc_estate_rl(new));
1747 else
1748 set_extra_mod(name, sym, alloc_estate_rl(new));
1749 }
1750
1751 free:
1752 free_string(name);
1753 }
1754
1755 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1756 {
1757 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
1758 }
1759
1760 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1761 {
1762 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
1763 }
1764
1765 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
1766 {
1767 struct expression *arg;
1768 char *name;
1769 struct symbol *sym;
1770 struct symbol *type;
1771 struct smatch_state *state;
1772 struct range_list *new = NULL;
1773 struct range_list *added = NULL;
1774
1775 while (expr->type == EXPR_ASSIGNMENT)
1776 expr = strip_expr(expr->right);
1777 if (expr->type != EXPR_CALL)
1778 return;
1779
1780 arg = get_argument_from_call_expr(expr->args, param);
1781 if (!arg)
1782 return;
1783 type = get_member_type_from_key(arg, key);
1784 name = get_variable_from_key(arg, key, &sym);
1785 if (!name || !sym)
1786 goto free;
1787
1788 state = get_state(SMATCH_EXTRA, name, sym);
1789 if (state)
1790 new = estate_rl(state);
1791
1792 call_results_to_rl(expr, type, value, &added);
1793
1794 if (op == PARAM_SET)
1795 new = added;
1796 else
1797 new = rl_union(new, added);
1798
1799 set_extra_mod(name, sym, alloc_estate_rl(new));
1800 free:
1801 free_string(name);
1802 }
1803
1804 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1805 {
1806 db_param_add_set(expr, param, key, value, PARAM_ADD);
1807 }
1808
1809 static void db_param_set(struct expression *expr, int param, char *key, char *value)
1810 {
1811 db_param_add_set(expr, param, key, value, PARAM_SET);
1812 }
1813
1814 static void match_call_info(struct expression *expr)
1815 {
1816 struct smatch_state *state;
1817 struct range_list *rl = NULL;
1818 struct expression *arg;
1819 struct symbol *type;
1820 int i = 0;
1821
1822 FOR_EACH_PTR(expr->args, arg) {
1823 type = get_arg_type(expr->fn, i);
1824
1825 if (get_implied_rl(arg, &rl))
1826 rl = cast_rl(type, rl);
1827 else
1828 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1829
1830 if (!is_whole_rl(rl))
1831 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
1832 state = get_state_expr(SMATCH_EXTRA, arg);
1833 if (estate_has_fuzzy_max(state)) {
1834 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
1835 sval_to_str(estate_get_fuzzy_max(state)));
1836 }
1837 i++;
1838 } END_FOR_EACH_PTR(arg);
1839 }
1840
1841 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1842 {
1843 struct range_list *rl = NULL;
1844 struct smatch_state *state;
1845 struct symbol *type;
1846 char fullname[256];
1847
1848 if (strcmp(key, "*$") == 0)
1849 snprintf(fullname, sizeof(fullname), "*%s", name);
1850 else if (strncmp(key, "$", 1) == 0)
1851 snprintf(fullname, 256, "%s%s", name, key + 1);
1852 else
1853 return;
1854
1855 type = get_member_type_from_key(symbol_expression(sym), key);
1856 str_to_rl(type, value, &rl);
1857 state = alloc_estate_rl(rl);
1858 set_state(SMATCH_EXTRA, fullname, sym, state);
1859 }
1860
1861 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
1862 {
1863 struct range_list *rl = NULL;
1864 struct smatch_state *state;
1865 struct symbol *type;
1866 char fullname[256];
1867 sval_t max;
1868
1869 if (strcmp(key, "*$") == 0)
1870 snprintf(fullname, sizeof(fullname), "*%s", name);
1871 else if (strncmp(key, "$", 1) == 0)
1872 snprintf(fullname, 256, "%s%s", name, key + 1);
1873 else
1874 return;
1875
1876 state = get_state(SMATCH_EXTRA, fullname, sym);
1877 if (!state)
1878 return;
1879 type = get_member_type_from_key(symbol_expression(sym), key);
1880 str_to_rl(type, value, &rl);
1881 if (!rl_to_sval(rl, &max))
1882 return;
1883 estate_set_fuzzy_max(state, max);
1884 }
1885
1886 struct smatch_state *get_extra_state(struct expression *expr)
1887 {
1888 char *name;
1889 struct symbol *sym;
1890 struct smatch_state *ret = NULL;
1891 struct range_list *rl;
1892
1893 if (is_pointer(expr) && get_address_rl(expr, &rl))
1894 return alloc_estate_rl(rl);
1895
1896 name = expr_to_known_chunk_sym(expr, &sym);
1897 if (!name)
1898 goto free;
1899
1900 ret = get_state(SMATCH_EXTRA, name, sym);
1901 free:
1902 free_string(name);
1903 return ret;
1904 }
1905
1906 void register_smatch_extra(int id)
1907 {
1908 my_id = id;
1909
1910 add_merge_hook(my_id, &merge_estates);
1911 add_unmatched_state_hook(my_id, &unmatched_state);
1912 select_caller_info_hook(set_param_value, PARAM_VALUE);
1913 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
1914 select_return_states_before(&db_limited_before);
1915 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
1916 select_return_states_hook(PARAM_FILTER, &db_param_filter);
1917 select_return_states_hook(PARAM_ADD, &db_param_add);
1918 select_return_states_hook(PARAM_SET, &db_param_set);
1919 select_return_states_after(&db_limited_after);
1920 }
1921
1922 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
1923 {
1924 struct var_sym_list *links;
1925 struct var_sym *tmp;
1926 struct smatch_state *state;
1927
1928 links = sm->state->data;
1929
1930 FOR_EACH_PTR(links, tmp) {
1931 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
1932 if (!state)
1933 continue;
1934 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
1935 } END_FOR_EACH_PTR(tmp);
1936 set_state(link_id, sm->name, sm->sym, &undefined);
1937 }
1938
1939 void register_smatch_extra_links(int id)
1940 {
1941 link_id = id;
1942 }
1943
1944 void register_smatch_extra_late(int id)
1945 {
1946 add_merge_hook(link_id, &merge_link_states);
1947 add_modification_hook(link_id, &match_link_modify);
1948 add_hook(&match_dereferences, DEREF_HOOK);
1949 add_hook(&match_pointer_as_array, OP_HOOK);
1950 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
1951 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1952 add_hook(&match_assign, ASSIGNMENT_HOOK);
1953 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
1954 add_hook(&unop_expr, OP_HOOK);
1955 add_hook(&asm_expr, ASM_HOOK);
1956 add_untracked_param_hook(&match_untracked_array);
1957
1958 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1959 add_member_info_callback(my_id, struct_member_callback);
1960
1961 add_hook(&assume_indexes_are_valid, OP_HOOK);
1962 }
Static analysis for C