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extra: handle returned struct members
[smatch.git] / smatch_extra.c
blob432a315f4273c915bebbc67b2c91ef4bd0cdd27d
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 sm = set_extra_mod_helper(name, sym, state);
145 new_name = get_other_name_sym(name, sym, &new_sym);
146 if (new_name && new_sym)
147 set_extra_mod_helper(new_name, new_sym, state);
148 free_string(new_name);
149 return sm;
150 }
151
152 static void clear_array_states(struct expression *array)
153 {
154 struct sm_state *sm;
155
156 sm = get_sm_state_expr(link_id, array);
157 if (sm)
158 match_link_modify(sm, NULL);
159 }
160
161 static struct sm_state *set_extra_array_mod(struct expression *expr, struct smatch_state *state)
162 {
163 struct expression *array;
164 struct expression *offset;
165 struct var_sym_list *vsl;
166 struct var_sym *vs;
167 char *name;
168 struct symbol *sym;
169 sval_t sval;
170 struct sm_state *ret = NULL;
171
172 array = get_array_base(expr);
173 offset = get_array_offset(expr);
174
175 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
176
177 if (!name || !vsl || !get_value(offset, &sval)) {
178 clear_array_states(array);
179 goto free;
180 }
181
182 FOR_EACH_PTR(vsl, vs) {
183 store_link(link_id, vs->var, vs->sym, name, sym);
184 } END_FOR_EACH_PTR(vs);
185
186 ret = set_state(SMATCH_EXTRA, name, sym, state);
187 free:
188 free_string(name);
189 return ret;
190 }
191
192 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
193 {
194 struct symbol *sym;
195 char *name;
196 struct sm_state *ret = NULL;
197
198 if (is_array(expr))
199 return set_extra_array_mod(expr, state);
200
201 expr = strip_expr(expr);
202 name = expr_to_var_sym(expr, &sym);
203 if (!name || !sym)
204 goto free;
205 ret = set_extra_mod(name, sym, state);
206 free:
207 free_string(name);
208 return ret;
209 }
210
211 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
212 {
213 char *new_name;
214 struct symbol *new_sym;
215 struct relation *rel;
216 struct smatch_state *orig_state;
217
218 orig_state = get_state(SMATCH_EXTRA, name, sym);
219
220 new_name = get_other_name_sym(name, sym, &new_sym);
221 if (new_name && new_sym)
222 set_state(SMATCH_EXTRA, new_name, new_sym, state);
223 free_string(new_name);
224
225 if (!estate_related(orig_state)) {
226 set_state(SMATCH_EXTRA, name, sym, state);
227 return;
228 }
229
230 set_related(state, estate_related(orig_state));
231 FOR_EACH_PTR(estate_related(orig_state), rel) {
232 struct smatch_state *estate;
233
234 if (option_debug_related)
235 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
236 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
237 if (!estate)
238 continue;
239 set_state(SMATCH_EXTRA, rel->name, rel->sym, clone_estate_cast(estate_type(estate), state));
240 } END_FOR_EACH_PTR(rel);
241 }
242
243 /*
244 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
245 */
246 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
247 {
248 char *name;
249 struct symbol *sym;
250
251 name = expr_to_var_sym(expr, &sym);
252 if (!name || !sym)
253 goto free;
254 set_extra_nomod(name, sym, state);
255 free:
256 free_string(name);
257
258 }
259
260 static void set_extra_true_false(const char *name, struct symbol *sym,
261 struct smatch_state *true_state,
262 struct smatch_state *false_state)
263 {
264 char *new_name;
265 struct symbol *new_sym;
266 struct relation *rel;
267 struct smatch_state *orig_state;
268
269 if (in_warn_on_macro())
270 return;
271
272 new_name = get_other_name_sym(name, sym, &new_sym);
273 if (new_name && new_sym)
274 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
275 free_string(new_name);
276
277 orig_state = get_state(SMATCH_EXTRA, name, sym);
278
279 if (!estate_related(orig_state)) {
280 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
281 return;
282 }
283
284 if (true_state)
285 set_related(true_state, estate_related(orig_state));
286 if (false_state)
287 set_related(false_state, estate_related(orig_state));
288
289 FOR_EACH_PTR(estate_related(orig_state), rel) {
290 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
291 true_state, false_state);
292 } END_FOR_EACH_PTR(rel);
293 }
294
295 static void set_extra_chunk_true_false(struct expression *expr,
296 struct smatch_state *true_state,
297 struct smatch_state *false_state)
298 {
299 struct var_sym_list *vsl;
300 struct var_sym *vs;
301 struct symbol *type;
302 char *name;
303 struct symbol *sym;
304
305 if (in_warn_on_macro())
306 return;
307
308 type = get_type(expr);
309 if (!type)
310 return;
311
312 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
313 if (!name || !vsl)
314 goto free;
315 FOR_EACH_PTR(vsl, vs) {
316 store_link(link_id, vs->var, vs->sym, name, sym);
317 } END_FOR_EACH_PTR(vs);
318
319 set_true_false_states(SMATCH_EXTRA, name, sym,
320 clone_estate(true_state),
321 clone_estate(false_state));
322 free:
323 free_string(name);
324 }
325
326 static void set_extra_expr_true_false(struct expression *expr,
327 struct smatch_state *true_state,
328 struct smatch_state *false_state)
329 {
330 char *name;
331 struct symbol *sym;
332 sval_t sval;
333
334 if (get_value(expr, &sval))
335 return;
336
337 expr = strip_expr(expr);
338 name = expr_to_var_sym(expr, &sym);
339 if (!name || !sym) {
340 free_string(name);
341 set_extra_chunk_true_false(expr, true_state, false_state);
342 return;
343 }
344 set_extra_true_false(name, sym, true_state, false_state);
345 free_string(name);
346 }
347
348 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
349 {
350 struct expression *iter_var;
351 struct expression *condition;
352 struct sm_state *sm;
353 struct smatch_state *estate;
354 sval_t start;
355
356 condition = strip_expr(loop->iterator_pre_condition);
357 if (!condition)
358 return NULL;
359 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
360 return NULL;
361 if (condition->op != SPECIAL_DECREMENT)
362 return NULL;
363
364 iter_var = condition->unop;
365 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
366 if (!sm)
367 return NULL;
368 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
369 return NULL;
370 start = estate_max(sm->state);
371 if (sval_cmp_val(start, 0) <= 0)
372 return NULL;
373 if (!sval_is_max(start))
374 start.value--;
375
376 if (condition->type == EXPR_PREOP) {
377 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
378 if (estate_has_hard_max(sm->state))
379 estate_set_hard_max(estate);
380 estate_copy_fuzzy_max(estate, sm->state);
381 set_extra_expr_mod(iter_var, estate);
382 }
383 if (condition->type == EXPR_POSTOP) {
384 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
385 if (estate_has_hard_max(sm->state))
386 estate_set_hard_max(estate);
387 estate_copy_fuzzy_max(estate, sm->state);
388 set_extra_expr_mod(iter_var, estate);
389 }
390 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
391 }
392
393 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
394 struct expression *condition)
395 {
396 struct expression *iter_var;
397 struct sm_state *sm;
398 struct smatch_state *estate;
399 sval_t start, end, max;
400
401 iter_var = iter_expr->unop;
402 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
403 if (!sm)
404 return NULL;
405 if (!estate_get_single_value(sm->state, &start))
406 return NULL;
407 if (get_implied_max(condition->right, &end))
408 end = sval_cast(get_type(iter_var), end);
409 else
410 end = sval_type_max(get_type(iter_var));
411
412 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
413 return NULL;
414
415 switch (condition->op) {
416 case SPECIAL_UNSIGNED_LT:
417 case SPECIAL_NOTEQUAL:
418 case '<':
419 if (!sval_is_min(end))
420 end.value--;
421 break;
422 case SPECIAL_UNSIGNED_LTE:
423 case SPECIAL_LTE:
424 break;
425 default:
426 return NULL;
427 }
428 if (sval_cmp(end, start) < 0)
429 return NULL;
430 estate = alloc_estate_range(start, end);
431 if (get_hard_max(condition->right, &max)) {
432 estate_set_hard_max(estate);
433 if (condition->op == '<' ||
434 condition->op == SPECIAL_UNSIGNED_LT ||
435 condition->op == SPECIAL_NOTEQUAL)
436 max.value--;
437 estate_set_fuzzy_max(estate, max);
438 }
439 set_extra_expr_mod(iter_var, estate);
440 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
441 }
442
443 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
444 struct expression *condition)
445 {
446 struct expression *iter_var;
447 struct sm_state *sm;
448 struct smatch_state *estate;
449 sval_t start, end;
450
451 iter_var = iter_expr->unop;
452 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
453 if (!sm)
454 return NULL;
455 if (!estate_get_single_value(sm->state, &start))
456 return NULL;
457 if (!get_implied_min(condition->right, &end))
458 end = sval_type_min(get_type(iter_var));
459 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
460 return NULL;
461
462 switch (condition->op) {
463 case SPECIAL_NOTEQUAL:
464 case '>':
465 if (!sval_is_min(end) && !sval_is_max(end))
466 end.value++;
467 break;
468 case SPECIAL_GTE:
469 break;
470 default:
471 return NULL;
472 }
473 if (sval_cmp(end, start) > 0)
474 return NULL;
475 estate = alloc_estate_range(end, start);
476 estate_set_hard_max(estate);
477 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
478 set_extra_expr_mod(iter_var, estate);
479 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
480 }
481
482 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
483 {
484 struct expression *iter_expr;
485 struct expression *condition;
486
487 if (!loop->iterator_post_statement)
488 return NULL;
489 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
490 return NULL;
491 iter_expr = loop->iterator_post_statement->expression;
492 if (!loop->iterator_pre_condition)
493 return NULL;
494 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
495 return NULL;
496 condition = loop->iterator_pre_condition;
497
498 if (iter_expr->op == SPECIAL_INCREMENT)
499 return handle_canonical_for_inc(iter_expr, condition);
500 if (iter_expr->op == SPECIAL_DECREMENT)
501 return handle_canonical_for_dec(iter_expr, condition);
502 return NULL;
503 }
504
505 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
506 {
507 struct sm_state *ret;
508
509 __push_fake_cur_stree();
510 if (!loop->iterator_post_statement)
511 ret = handle_canonical_while_count_down(loop);
512 else
513 ret = handle_canonical_for_loops(loop);
514 *stree = __pop_fake_cur_stree();
515 return ret;
516 }
517
518 int __iterator_unchanged(struct sm_state *sm)
519 {
520 if (!sm)
521 return 0;
522 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
523 return 1;
524 return 0;
525 }
526
527 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
528 {
529 sval_t after_value;
530
531 /* paranoid checking. prolly not needed */
532 condition = strip_expr(condition);
533 if (!condition)
534 return;
535 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
536 return;
537 if (condition->op != SPECIAL_DECREMENT)
538 return;
539 after_value = estate_min(sm->state);
540 after_value.value--;
541 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
542 }
543
544 void __extra_pre_loop_hook_after(struct sm_state *sm,
545 struct statement *iterator,
546 struct expression *condition)
547 {
548 struct expression *iter_expr;
549 sval_t limit;
550 struct smatch_state *state;
551
552 if (!iterator) {
553 while_count_down_after(sm, condition);
554 return;
555 }
556
557 iter_expr = iterator->expression;
558
559 if (condition->type != EXPR_COMPARE)
560 return;
561 if (iter_expr->op == SPECIAL_INCREMENT) {
562 limit = sval_binop(estate_max(sm->state), '+',
563 sval_type_val(estate_type(sm->state), 1));
564 } else {
565 limit = sval_binop(estate_min(sm->state), '-',
566 sval_type_val(estate_type(sm->state), 1));
567 }
568 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
569 if (iter_expr->op == SPECIAL_INCREMENT)
570 state = alloc_estate_range(estate_min(sm->state), limit);
571 else
572 state = alloc_estate_range(limit, estate_max(sm->state));
573 } else {
574 state = alloc_estate_sval(limit);
575 }
576 if (!estate_has_hard_max(sm->state)) {
577 estate_clear_hard_max(state);
578 }
579 if (estate_has_fuzzy_max(sm->state)) {
580 sval_t hmax = estate_get_fuzzy_max(sm->state);
581 sval_t max = estate_max(sm->state);
582
583 if (sval_cmp(hmax, max) != 0)
584 estate_clear_fuzzy_max(state);
585 } else if (!estate_has_fuzzy_max(sm->state)) {
586 estate_clear_fuzzy_max(state);
587 }
588
589 set_extra_mod(sm->name, sm->sym, state);
590 }
591
592 static struct stree *unmatched_stree;
593 static struct smatch_state *unmatched_state(struct sm_state *sm)
594 {
595 struct smatch_state *state;
596
597 if (unmatched_stree) {
598 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
599 if (state)
600 return state;
601 }
602 if (parent_is_gone_var_sym(sm->name, sm->sym))
603 return alloc_estate_empty();
604 return alloc_estate_whole(estate_type(sm->state));
605 }
606
607 static void clear_the_pointed_at(struct expression *expr)
608 {
609 struct stree *stree;
610 char *name;
611 struct symbol *sym;
612 struct sm_state *tmp;
613
614 name = expr_to_var_sym(expr, &sym);
615 if (!name || !sym)
616 goto free;
617
618 stree = __get_cur_stree();
619 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
620 if (tmp->name[0] != '*')
621 continue;
622 if (tmp->sym != sym)
623 continue;
624 if (strcmp(tmp->name + 1, name) != 0)
625 continue;
626 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
627 } END_FOR_EACH_SM(tmp);
628
629 free:
630 free_string(name);
631 }
632
633 static void match_function_call(struct expression *expr)
634 {
635 struct expression *arg;
636 struct expression *tmp;
637
638 /* if we have the db this is handled in smatch_function_hooks.c */
639 if (!option_no_db)
640 return;
641 if (inlinable(expr->fn))
642 return;
643
644 FOR_EACH_PTR(expr->args, arg) {
645 tmp = strip_expr(arg);
646 if (tmp->type == EXPR_PREOP && tmp->op == '&')
647 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
648 else
649 clear_the_pointed_at(tmp);
650 } END_FOR_EACH_PTR(arg);
651 }
652
653 static int values_fit_type(struct expression *left, struct expression *right)
654 {
655 struct range_list *rl;
656 struct symbol *type;
657
658 type = get_type(left);
659 if (!type)
660 return 0;
661 get_absolute_rl(right, &rl);
662 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
663 return 0;
664 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
665 return 0;
666 return 1;
667 }
668
669 static void save_chunk_info(struct expression *left, struct expression *right)
670 {
671 struct var_sym_list *vsl;
672 struct var_sym *vs;
673 struct expression *add_expr;
674 struct symbol *type;
675 sval_t sval;
676 char *name;
677 struct symbol *sym;
678
679 if (right->type != EXPR_BINOP || right->op != '-')
680 return;
681 if (!get_value(right->left, &sval))
682 return;
683 if (!expr_to_sym(right->right))
684 return;
685
686 add_expr = binop_expression(left, '+', right->right);
687 type = get_type(add_expr);
688 if (!type)
689 return;
690 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
691 if (!name || !vsl)
692 goto free;
693 FOR_EACH_PTR(vsl, vs) {
694 store_link(link_id, vs->var, vs->sym, name, sym);
695 } END_FOR_EACH_PTR(vs);
696
697 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
698 free:
699 free_string(name);
700 }
701
702 static void do_array_assign(struct expression *left, int op, struct expression *right)
703 {
704 struct range_list *rl;
705
706 if (op == '=') {
707 get_absolute_rl(right, &rl);
708 rl = cast_rl(get_type(left), rl);
709 } else {
710 rl = alloc_whole_rl(get_type(left));
711 }
712
713 set_extra_array_mod(left, alloc_estate_rl(rl));
714 }
715
716 static void match_untracked_array(struct expression *call, int param)
717 {
718 struct expression *arg;
719
720 arg = get_argument_from_call_expr(call->args, param);
721 arg = strip_expr(arg);
722
723 clear_array_states(arg);
724 }
725
726 static void match_vanilla_assign(struct expression *left, struct expression *right)
727 {
728 struct range_list *rl = NULL;
729 struct symbol *right_sym;
730 struct symbol *left_type;
731 struct symbol *right_type;
732 char *right_name = NULL;
733 struct symbol *sym;
734 char *name;
735 sval_t max;
736 struct smatch_state *state;
737
738 if (is_struct(left))
739 return;
740
741 save_chunk_info(left, right);
742
743 name = expr_to_var_sym(left, &sym);
744 if (!name) {
745 if (is_array(left))
746 do_array_assign(left, '=', right);
747 return;
748 }
749
750 left_type = get_type(left);
751 right_type = get_type(right);
752
753 right_name = expr_to_var_sym(right, &right_sym);
754
755 if (!__in_fake_assign &&
756 !(right->type == EXPR_PREOP && right->op == '&') &&
757 right_name && right_sym &&
758 values_fit_type(left, right) &&
759 !has_symbol(right, sym)) {
760 set_equiv(left, right);
761 goto free;
762 }
763
764 if (is_pointer(right) && get_address_rl(right, &rl)) {
765 state = alloc_estate_rl(rl);
766 } else if (get_implied_rl(right, &rl)) {
767 rl = cast_rl(left_type, rl);
768 state = alloc_estate_rl(rl);
769 if (get_hard_max(right, &max)) {
770 estate_set_hard_max(state);
771 estate_set_fuzzy_max(state, max);
772 }
773 } else {
774 rl = alloc_whole_rl(right_type);
775 rl = cast_rl(left_type, rl);
776 state = alloc_estate_rl(rl);
777 }
778 set_extra_mod(name, sym, state);
779 free:
780 free_string(right_name);
781 }
782
783 static int op_remove_assign(int op)
784 {
785 switch (op) {
786 case SPECIAL_ADD_ASSIGN:
787 return '+';
788 case SPECIAL_SUB_ASSIGN:
789 return '-';
790 case SPECIAL_MUL_ASSIGN:
791 return '*';
792 case SPECIAL_DIV_ASSIGN:
793 return '/';
794 case SPECIAL_MOD_ASSIGN:
795 return '%';
796 case SPECIAL_AND_ASSIGN:
797 return '&';
798 case SPECIAL_OR_ASSIGN:
799 return '|';
800 case SPECIAL_XOR_ASSIGN:
801 return '^';
802 case SPECIAL_SHL_ASSIGN:
803 return SPECIAL_LEFTSHIFT;
804 case SPECIAL_SHR_ASSIGN:
805 return SPECIAL_RIGHTSHIFT;
806 default:
807 return op;
808 }
809 }
810
811 static void match_assign(struct expression *expr)
812 {
813 struct range_list *rl = NULL;
814 struct expression *left;
815 struct expression *right;
816 struct expression *binop_expr;
817 struct symbol *left_type;
818 struct symbol *right_type;
819 struct symbol *sym;
820 char *name;
821 sval_t left_min, left_max;
822 sval_t right_min, right_max;
823 sval_t res_min, res_max;
824
825 left = strip_expr(expr->left);
826
827 right = strip_parens(expr->right);
828 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
829 right = get_argument_from_call_expr(right->args, 0);
830 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
831 right = strip_parens(right->left);
832
833 if (expr->op == '=' && is_condition(expr->right))
834 return; /* handled in smatch_condition.c */
835 if (expr->op == '=' && right->type == EXPR_CALL)
836 return; /* handled in smatch_function_hooks.c */
837 if (expr->op == '=') {
838 match_vanilla_assign(left, right);
839 return;
840 }
841
842 name = expr_to_var_sym(left, &sym);
843 if (!name)
844 return;
845
846 left_type = get_type(left);
847 right_type = get_type(right);
848
849 res_min = sval_type_min(left_type);
850 res_max = sval_type_max(left_type);
851
852 switch (expr->op) {
853 case SPECIAL_ADD_ASSIGN:
854 get_absolute_max(left, &left_max);
855 get_absolute_max(right, &right_max);
856 if (sval_binop_overflows(left_max, '+', right_max))
857 break;
858 if (get_implied_min(left, &left_min) &&
859 !sval_is_negative_min(left_min) &&
860 get_implied_min(right, &right_min) &&
861 !sval_is_negative_min(right_min)) {
862 res_min = sval_binop(left_min, '+', right_min);
863 res_min = sval_cast(right_type, res_min);
864 }
865 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
866 break;
867 res_max = sval_binop(left_max, '+', right_max);
868 res_max = sval_cast(right_type, res_max);
869 break;
870 case SPECIAL_SUB_ASSIGN:
871 if (get_implied_max(left, &left_max) &&
872 !sval_is_max(left_max) &&
873 get_implied_min(right, &right_min) &&
874 !sval_is_min(right_min)) {
875 res_max = sval_binop(left_max, '-', right_min);
876 res_max = sval_cast(right_type, res_max);
877 }
878 if (inside_loop())
879 break;
880 if (get_implied_min(left, &left_min) &&
881 !sval_is_min(left_min) &&
882 get_implied_max(right, &right_max) &&
883 !sval_is_max(right_max)) {
884 res_min = sval_binop(left_min, '-', right_max);
885 res_min = sval_cast(right_type, res_min);
886 }
887 break;
888 case SPECIAL_AND_ASSIGN:
889 case SPECIAL_MOD_ASSIGN:
890 case SPECIAL_SHL_ASSIGN:
891 case SPECIAL_SHR_ASSIGN:
892 case SPECIAL_OR_ASSIGN:
893 case SPECIAL_XOR_ASSIGN:
894 case SPECIAL_MUL_ASSIGN:
895 case SPECIAL_DIV_ASSIGN:
896 binop_expr = binop_expression(expr->left,
897 op_remove_assign(expr->op),
898 expr->right);
899 if (get_absolute_rl(binop_expr, &rl)) {
900 rl = cast_rl(left_type, rl);
901 set_extra_mod(name, sym, alloc_estate_rl(rl));
902 goto free;
903 }
904 break;
905 }
906 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
907 set_extra_mod(name, sym, alloc_estate_rl(rl));
908 free:
909 free_string(name);
910 }
911
912 static struct smatch_state *increment_state(struct smatch_state *state)
913 {
914 sval_t min = estate_min(state);
915 sval_t max = estate_max(state);
916
917 if (!estate_rl(state))
918 return NULL;
919
920 if (inside_loop())
921 max = sval_type_max(max.type);
922
923 if (!sval_is_min(min) && !sval_is_max(min))
924 min.value++;
925 if (!sval_is_min(max) && !sval_is_max(max))
926 max.value++;
927 return alloc_estate_range(min, max);
928 }
929
930 static struct smatch_state *decrement_state(struct smatch_state *state)
931 {
932 sval_t min = estate_min(state);
933 sval_t max = estate_max(state);
934
935 if (!estate_rl(state))
936 return NULL;
937
938 if (inside_loop())
939 min = sval_type_min(min.type);
940
941 if (!sval_is_min(min) && !sval_is_max(min))
942 min.value--;
943 if (!sval_is_min(max) && !sval_is_max(max))
944 max.value--;
945 return alloc_estate_range(min, max);
946 }
947
948 static void unop_expr(struct expression *expr)
949 {
950 struct smatch_state *state;
951
952 if (expr->smatch_flags & Handled)
953 return;
954
955 switch (expr->op) {
956 case SPECIAL_INCREMENT:
957 state = get_state_expr(SMATCH_EXTRA, expr->unop);
958 state = increment_state(state);
959 if (!state)
960 state = alloc_estate_whole(get_type(expr));
961 set_extra_expr_mod(expr->unop, state);
962 break;
963 case SPECIAL_DECREMENT:
964 state = get_state_expr(SMATCH_EXTRA, expr->unop);
965 state = decrement_state(state);
966 if (!state)
967 state = alloc_estate_whole(get_type(expr));
968 set_extra_expr_mod(expr->unop, state);
969 break;
970 default:
971 return;
972 }
973 }
974
975 static void asm_expr(struct statement *stmt)
976 {
977
978 struct expression *expr;
979 struct symbol *type;
980 int state = 0;
981
982 FOR_EACH_PTR(stmt->asm_outputs, expr) {
983 switch (state) {
984 case 0: /* identifier */
985 case 1: /* constraint */
986 state++;
987 continue;
988 case 2: /* expression */
989 state = 0;
990 type = get_type(strip_expr(expr));
991 set_extra_expr_mod(expr, alloc_estate_whole(type));
992 continue;
993 }
994 } END_FOR_EACH_PTR(expr);
995 }
996
997 static void check_dereference(struct expression *expr)
998 {
999 if (outside_of_function())
1000 return;
1001 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1002 }
1003
1004 static void match_dereferences(struct expression *expr)
1005 {
1006 if (expr->type != EXPR_PREOP)
1007 return;
1008 check_dereference(expr->unop);
1009 }
1010
1011 static void match_pointer_as_array(struct expression *expr)
1012 {
1013 if (!is_array(expr))
1014 return;
1015 check_dereference(get_array_base(expr));
1016 }
1017
1018 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
1019 {
1020 struct symbol *sym;
1021 char *name;
1022
1023 name = get_variable_from_key(arg, key, &sym);
1024 if (!name || !sym)
1025 goto free;
1026
1027 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1028
1029 free:
1030 free_string(name);
1031 }
1032
1033 static sval_t add_one(sval_t sval)
1034 {
1035 sval.value++;
1036 return sval;
1037 }
1038
1039 static sval_t sub_one(sval_t sval)
1040 {
1041 sval.value--;
1042 return sval;
1043 }
1044
1045 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1046 {
1047 struct range_list *left_orig;
1048 struct range_list *left_true;
1049 struct range_list *left_false;
1050 struct range_list *right_orig;
1051 struct range_list *right_true;
1052 struct range_list *right_false;
1053 struct smatch_state *left_true_state;
1054 struct smatch_state *left_false_state;
1055 struct smatch_state *right_true_state;
1056 struct smatch_state *right_false_state;
1057 sval_t min, max, dummy, hard_max;
1058 int left_postop = 0;
1059 int right_postop = 0;
1060
1061 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1062 if (left->type == EXPR_POSTOP) {
1063 left->smatch_flags |= Handled;
1064 left_postop = left->op;
1065 }
1066 left = strip_parens(left->unop);
1067 }
1068 while (left->type == EXPR_ASSIGNMENT)
1069 left = strip_parens(left->left);
1070
1071 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1072 if (right->type == EXPR_POSTOP) {
1073 right->smatch_flags |= Handled;
1074 right_postop = right->op;
1075 }
1076 right = strip_parens(right->unop);
1077 }
1078
1079 if (get_implied_rl(left, &left_orig)) {
1080 left_orig = cast_rl(type, left_orig);
1081 } else {
1082 min = sval_type_min(get_type(left));
1083 max = sval_type_max(get_type(left));
1084 left_orig = cast_rl(type, alloc_rl(min, max));
1085 }
1086
1087 if (get_implied_rl(right, &right_orig)) {
1088 right_orig = cast_rl(type, right_orig);
1089 } else {
1090 min = sval_type_min(get_type(right));
1091 max = sval_type_max(get_type(right));
1092 right_orig = cast_rl(type, alloc_rl(min, max));
1093 }
1094 min = sval_type_min(type);
1095 max = sval_type_max(type);
1096
1097 left_true = clone_rl(left_orig);
1098 left_false = clone_rl(left_orig);
1099 right_true = clone_rl(right_orig);
1100 right_false = clone_rl(right_orig);
1101
1102 switch (op) {
1103 case '<':
1104 case SPECIAL_UNSIGNED_LT:
1105 left_true = remove_range(left_orig, rl_max(right_orig), max);
1106 if (!sval_is_min(rl_min(right_orig))) {
1107 left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1108 }
1109
1110 right_true = remove_range(right_orig, min, rl_min(left_orig));
1111 if (!sval_is_max(rl_max(left_orig)))
1112 right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1113 break;
1114 case SPECIAL_UNSIGNED_LTE:
1115 case SPECIAL_LTE:
1116 if (!sval_is_max(rl_max(right_orig)))
1117 left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1118 left_false = remove_range(left_orig, min, rl_min(right_orig));
1119
1120 if (!sval_is_min(rl_min(left_orig)))
1121 right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1122 right_false = remove_range(right_orig, rl_max(left_orig), max);
1123
1124 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1125 left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
1126 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1127 right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
1128 break;
1129 case SPECIAL_EQUAL:
1130 if (!sval_is_max(rl_max(right_orig))) {
1131 left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
1132 }
1133 if (!sval_is_min(rl_min(right_orig))) {
1134 left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
1135 }
1136 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1137 left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1138
1139 if (!sval_is_max(rl_max(left_orig)))
1140 right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
1141 if (!sval_is_min(rl_min(left_orig)))
1142 right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
1143 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1144 right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1145 break;
1146 case SPECIAL_UNSIGNED_GTE:
1147 case SPECIAL_GTE:
1148 if (!sval_is_min(rl_min(right_orig)))
1149 left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1150 left_false = remove_range(left_orig, rl_max(right_orig), max);
1151
1152 if (!sval_is_max(rl_max(left_orig)))
1153 right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1154 right_false = remove_range(right_orig, min, rl_min(left_orig));
1155
1156 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1157 right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
1158 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1159 left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
1160 break;
1161 case '>':
1162 case SPECIAL_UNSIGNED_GT:
1163 left_true = remove_range(left_orig, min, rl_min(right_orig));
1164 if (!sval_is_max(rl_max(right_orig)))
1165 left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1166
1167 right_true = remove_range(right_orig, rl_max(left_orig), max);
1168 if (!sval_is_min(rl_min(left_orig)))
1169 right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1170 break;
1171 case SPECIAL_NOTEQUAL:
1172 if (!sval_is_max(rl_max(right_orig)))
1173 left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
1174 if (!sval_is_min(rl_min(right_orig)))
1175 left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
1176 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1177 left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1178
1179 if (!sval_is_max(rl_max(left_orig)))
1180 right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
1181 if (!sval_is_min(rl_min(left_orig)))
1182 right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
1183 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1184 right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1185 break;
1186 default:
1187 return;
1188 }
1189
1190 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1191 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1192 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1193 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1194
1195 left_true_state = alloc_estate_rl(left_true);
1196 left_false_state = alloc_estate_rl(left_false);
1197 right_true_state = alloc_estate_rl(right_true);
1198 right_false_state = alloc_estate_rl(right_false);
1199
1200 switch (op) {
1201 case '<':
1202 case SPECIAL_UNSIGNED_LT:
1203 case SPECIAL_UNSIGNED_LTE:
1204 case SPECIAL_LTE:
1205 if (get_hard_max(right, &dummy))
1206 estate_set_hard_max(left_true_state);
1207 if (get_hard_max(left, &dummy))
1208 estate_set_hard_max(right_false_state);
1209 break;
1210 case '>':
1211 case SPECIAL_UNSIGNED_GT:
1212 case SPECIAL_UNSIGNED_GTE:
1213 case SPECIAL_GTE:
1214 if (get_hard_max(left, &dummy))
1215 estate_set_hard_max(right_true_state);
1216 if (get_hard_max(right, &dummy))
1217 estate_set_hard_max(left_false_state);
1218 break;
1219 }
1220
1221 switch (op) {
1222 case '<':
1223 case SPECIAL_UNSIGNED_LT:
1224 case SPECIAL_UNSIGNED_LTE:
1225 case SPECIAL_LTE:
1226 if (get_hard_max(right, &hard_max)) {
1227 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1228 hard_max.value--;
1229 estate_set_fuzzy_max(left_true_state, hard_max);
1230 }
1231 if (get_implied_value(right, &hard_max)) {
1232 if (op == SPECIAL_UNSIGNED_LTE ||
1233 op == SPECIAL_LTE)
1234 hard_max.value++;
1235 estate_set_fuzzy_max(left_false_state, hard_max);
1236 }
1237 if (get_hard_max(left, &hard_max)) {
1238 if (op == SPECIAL_UNSIGNED_LTE ||
1239 op == SPECIAL_LTE)
1240 hard_max.value--;
1241 estate_set_fuzzy_max(right_false_state, hard_max);
1242 }
1243 if (get_implied_value(left, &hard_max)) {
1244 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1245 hard_max.value++;
1246 estate_set_fuzzy_max(right_true_state, hard_max);
1247 }
1248 break;
1249 case '>':
1250 case SPECIAL_UNSIGNED_GT:
1251 case SPECIAL_UNSIGNED_GTE:
1252 case SPECIAL_GTE:
1253 if (get_hard_max(left, &hard_max)) {
1254 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1255 hard_max.value--;
1256 estate_set_fuzzy_max(right_true_state, hard_max);
1257 }
1258 if (get_implied_value(left, &hard_max)) {
1259 if (op == SPECIAL_UNSIGNED_GTE ||
1260 op == SPECIAL_GTE)
1261 hard_max.value++;
1262 estate_set_fuzzy_max(right_false_state, hard_max);
1263 }
1264 if (get_hard_max(right, &hard_max)) {
1265 if (op == SPECIAL_UNSIGNED_LTE ||
1266 op == SPECIAL_LTE)
1267 hard_max.value--;
1268 estate_set_fuzzy_max(left_false_state, hard_max);
1269 }
1270 if (get_implied_value(right, &hard_max)) {
1271 if (op == '>' ||
1272 op == SPECIAL_UNSIGNED_GT)
1273 hard_max.value++;
1274 estate_set_fuzzy_max(left_true_state, hard_max);
1275 }
1276 break;
1277 case SPECIAL_EQUAL:
1278 if (get_hard_max(left, &hard_max))
1279 estate_set_fuzzy_max(right_true_state, hard_max);
1280 if (get_hard_max(right, &hard_max))
1281 estate_set_fuzzy_max(left_true_state, hard_max);
1282 break;
1283 }
1284
1285 if (get_hard_max(left, &hard_max)) {
1286 estate_set_hard_max(left_true_state);
1287 estate_set_hard_max(left_false_state);
1288 }
1289 if (get_hard_max(right, &hard_max)) {
1290 estate_set_hard_max(right_true_state);
1291 estate_set_hard_max(right_false_state);
1292 }
1293
1294 if (left_postop == SPECIAL_INCREMENT) {
1295 left_true_state = increment_state(left_true_state);
1296 left_false_state = increment_state(left_false_state);
1297 }
1298 if (left_postop == SPECIAL_DECREMENT) {
1299 left_true_state = decrement_state(left_true_state);
1300 left_false_state = decrement_state(left_false_state);
1301 }
1302 if (right_postop == SPECIAL_INCREMENT) {
1303 right_true_state = increment_state(right_true_state);
1304 right_false_state = increment_state(right_false_state);
1305 }
1306 if (right_postop == SPECIAL_DECREMENT) {
1307 right_true_state = decrement_state(right_true_state);
1308 right_false_state = decrement_state(right_false_state);
1309 }
1310
1311 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1312 left_true_state = NULL;
1313 left_false_state = NULL;
1314 }
1315
1316 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1317 right_true_state = NULL;
1318 right_false_state = NULL;
1319 }
1320
1321 set_extra_expr_true_false(left, left_true_state, left_false_state);
1322 set_extra_expr_true_false(right, right_true_state, right_false_state);
1323 }
1324
1325 static int is_simple_math(struct expression *expr)
1326 {
1327 if (!expr)
1328 return 0;
1329 if (expr->type != EXPR_BINOP)
1330 return 0;
1331 switch (expr->op) {
1332 case '+':
1333 case '-':
1334 case '*':
1335 return 1;
1336 }
1337 return 0;
1338 }
1339
1340 static void move_known_values(struct expression **left_p, struct expression **right_p)
1341 {
1342 struct expression *left = *left_p;
1343 struct expression *right = *right_p;
1344 sval_t sval;
1345
1346 if (get_implied_value(left, &sval)) {
1347 if (!is_simple_math(right))
1348 return;
1349 if (right->op == '*') {
1350 sval_t divisor;
1351
1352 if (!get_value(right->right, &divisor))
1353 return;
1354 if (divisor.value == 0 && sval.value % divisor.value)
1355 return;
1356 *left_p = binop_expression(left, invert_op(right->op), right->right);
1357 *right_p = right->left;
1358 return;
1359 }
1360 if (right->op == '+' && get_value(right->left, &sval)) {
1361 *left_p = binop_expression(left, invert_op(right->op), right->left);
1362 *right_p = right->right;
1363 return;
1364 }
1365 if (get_value(right->right, &sval)) {
1366 *left_p = binop_expression(left, invert_op(right->op), right->right);
1367 *right_p = right->left;
1368 return;
1369 }
1370 return;
1371 }
1372 if (get_implied_value(right, &sval)) {
1373 if (!is_simple_math(left))
1374 return;
1375 if (left->op == '*') {
1376 sval_t divisor;
1377
1378 if (!get_value(left->right, &divisor))
1379 return;
1380 if (divisor.value == 0 && sval.value % divisor.value)
1381 return;
1382 *right_p = binop_expression(right, invert_op(left->op), left->right);
1383 *left_p = left->left;
1384 return;
1385 }
1386 if (left->op == '+' && get_value(left->left, &sval)) {
1387 *right_p = binop_expression(right, invert_op(left->op), left->left);
1388 *left_p = left->right;
1389 return;
1390 }
1391
1392 if (get_value(left->right, &sval)) {
1393 *right_p = binop_expression(right, invert_op(left->op), left->right);
1394 *left_p = left->left;
1395 return;
1396 }
1397 return;
1398 }
1399 }
1400
1401 static int match_func_comparison(struct expression *expr)
1402 {
1403 struct expression *left = strip_expr(expr->left);
1404 struct expression *right = strip_expr(expr->right);
1405 sval_t sval;
1406
1407 /*
1408 * fixme: think about this harder. We should always be trying to limit
1409 * the non-call side as well. If we can't determine the limitter does
1410 * that mean we aren't querying the database and are missing important
1411 * information?
1412 */
1413
1414 if (left->type == EXPR_CALL) {
1415 if (get_implied_value(left, &sval)) {
1416 handle_comparison(get_type(expr), left, expr->op, right);
1417 return 1;
1418 }
1419 function_comparison(left, expr->op, right);
1420 return 1;
1421 }
1422
1423 if (right->type == EXPR_CALL) {
1424 if (get_implied_value(right, &sval)) {
1425 handle_comparison(get_type(expr), left, expr->op, right);
1426 return 1;
1427 }
1428 function_comparison(left, expr->op, right);
1429 return 1;
1430 }
1431
1432 return 0;
1433 }
1434
1435 static void match_comparison(struct expression *expr)
1436 {
1437 struct expression *left_orig = strip_parens(expr->left);
1438 struct expression *right_orig = strip_parens(expr->right);
1439 struct expression *left, *right;
1440 struct expression *prev;
1441 struct symbol *type;
1442
1443 if (match_func_comparison(expr))
1444 return;
1445
1446 type = get_type(expr);
1447 if (!type)
1448 type = &llong_ctype;
1449
1450 left = left_orig;
1451 right = right_orig;
1452 move_known_values(&left, &right);
1453 handle_comparison(type, left, expr->op, right);
1454
1455 prev = get_assigned_expr(left_orig);
1456 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1457 left = prev;
1458 right = right_orig;
1459 move_known_values(&left, &right);
1460 handle_comparison(type, left, expr->op, right);
1461 }
1462
1463 prev = get_assigned_expr(right_orig);
1464 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1465 left = left_orig;
1466 right = prev;
1467 move_known_values(&left, &right);
1468 handle_comparison(type, left, expr->op, right);
1469 }
1470 }
1471
1472 static void handle_AND_condition(struct expression *expr)
1473 {
1474 struct range_list *rl = NULL;
1475 sval_t known;
1476
1477 if (get_implied_value(expr->left, &known) && known.value > 0) {
1478 known.value--;
1479 get_absolute_rl(expr->right, &rl);
1480 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1481 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1482 return;
1483 }
1484
1485 if (get_implied_value(expr->right, &known) && known.value > 0) {
1486 known.value--;
1487 get_absolute_rl(expr->left, &rl);
1488 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1489 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1490 return;
1491 }
1492 }
1493
1494 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1495 void __extra_match_condition(struct expression *expr)
1496 {
1497 struct smatch_state *pre_state;
1498 struct smatch_state *true_state;
1499 struct smatch_state *false_state;
1500
1501 expr = strip_expr(expr);
1502 switch (expr->type) {
1503 case EXPR_CALL:
1504 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1505 return;
1506 case EXPR_PREOP:
1507 case EXPR_SYMBOL:
1508 case EXPR_DEREF: {
1509 sval_t zero;
1510
1511 zero = sval_blank(expr);
1512 zero.value = 0;
1513
1514 pre_state = get_extra_state(expr);
1515 true_state = estate_filter_sval(pre_state, zero);
1516 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1517 false_state = alloc_estate_sval(zero);
1518 else
1519 false_state = alloc_estate_empty();
1520 set_extra_expr_true_false(expr, true_state, false_state);
1521 return;
1522 }
1523 case EXPR_COMPARE:
1524 match_comparison(expr);
1525 return;
1526 case EXPR_ASSIGNMENT:
1527 __extra_match_condition(expr->left);
1528 return;
1529 case EXPR_BINOP:
1530 if (expr->op == '&')
1531 handle_AND_condition(expr);
1532 return;
1533 }
1534 }
1535
1536 static void assume_indexes_are_valid(struct expression *expr)
1537 {
1538 struct expression *array_expr;
1539 int array_size;
1540 struct expression *offset;
1541 struct symbol *offset_type;
1542 struct range_list *rl_before;
1543 struct range_list *rl_after;
1544 struct range_list *filter = NULL;
1545 sval_t size;
1546
1547 expr = strip_expr(expr);
1548 if (!is_array(expr))
1549 return;
1550
1551 offset = get_array_offset(expr);
1552 offset_type = get_type(offset);
1553 if (offset_type && type_signed(offset_type)) {
1554 filter = alloc_rl(sval_type_min(offset_type),
1555 sval_type_val(offset_type, -1));
1556 }
1557
1558 array_expr = get_array_base(expr);
1559 array_size = get_real_array_size(array_expr);
1560 if (array_size > 1) {
1561 size = sval_type_val(offset_type, array_size);
1562 add_range(&filter, size, sval_type_max(offset_type));
1563 }
1564
1565 if (!filter)
1566 return;
1567 get_absolute_rl(offset, &rl_before);
1568 rl_after = rl_filter(rl_before, filter);
1569 if (rl_equiv(rl_before, rl_after))
1570 return;
1571 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1572 }
1573
1574 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1575 int implied_not_equal(struct expression *expr, long long val)
1576 {
1577 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1578 }
1579
1580 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1581 {
1582 struct smatch_state *estate;
1583
1584 estate = get_state(SMATCH_EXTRA, name, sym);
1585 if (!estate)
1586 return 0;
1587 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1588 return 1;
1589 return 0;
1590 }
1591
1592 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1593 {
1594 char buf[256];
1595 char *start;
1596 char *end;
1597 struct smatch_state *state;
1598
1599 strncpy(buf, name, sizeof(buf) - 1);
1600 buf[sizeof(buf) - 1] = '\0';
1601
1602 start = &buf[0];
1603 while (*start == '*') {
1604 start++;
1605 state = get_state(SMATCH_EXTRA, start, sym);
1606 if (!state)
1607 continue;
1608 if (!estate_rl(state))
1609 return 1;
1610 if (estate_min(state).value == 0 &&
1611 estate_max(state).value == 0)
1612 return 1;
1613 }
1614
1615 start = &buf[0];
1616 while (*start == '&')
1617 start++;
1618
1619 while ((end = strrchr(start, '-'))) {
1620 *end = '\0';
1621 state = get_state(SMATCH_EXTRA, start, sym);
1622 if (!state)
1623 continue;
1624 if (estate_min(state).value == 0 &&
1625 estate_max(state).value == 0)
1626 return 1;
1627 }
1628 return 0;
1629 }
1630
1631 int parent_is_null(struct expression *expr)
1632 {
1633 struct symbol *sym;
1634 char *var;
1635 int ret = 0;
1636
1637 expr = strip_expr(expr);
1638 var = expr_to_var_sym(expr, &sym);
1639 if (!var || !sym)
1640 goto free;
1641 ret = parent_is_null_var_sym(var, sym);
1642 free:
1643 free_string(var);
1644 return ret;
1645 }
1646
1647 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
1648 {
1649 *(int *)found = 1;
1650 return 0;
1651 }
1652
1653 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1654 {
1655 sval_t sval;
1656 int found = 0;
1657
1658 /* for function pointers assume everything is used */
1659 if (call->fn->type != EXPR_SYMBOL)
1660 return 0;
1661
1662 /*
1663 * kzalloc() information is treated as special because so there is just
1664 * a lot of stuff initialized to zero and it makes building the database
1665 * take hours and hours.
1666 *
1667 * In theory, we should just remove this line and not pass any unused
1668 * information, but I'm not sure enough that this code works so I want
1669 * to hold off on that for now.
1670 */
1671 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
1672 return 0;
1673
1674 run_sql(&param_used_callback, &found,
1675 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
1676 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
1677 if (found)
1678 return 0;
1679
1680 /* If the database is not built yet, then assume everything is used */
1681 run_sql(&param_used_callback, &found,
1682 "select * from call_implies where %s and type = %d;",
1683 get_static_filter(call->fn->symbol), PARAM_USED);
1684 if (!found)
1685 return 0;
1686
1687 return 1;
1688 }
1689
1690 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1691 {
1692 if (estate_is_whole(sm->state))
1693 return;
1694 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
1695 return;
1696 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, sm->state->name);
1697 if (estate_has_fuzzy_max(sm->state))
1698 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1699 sval_to_str(estate_get_fuzzy_max(sm->state)));
1700 }
1701
1702 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
1703 {
1704 struct symbol *returned_sym;
1705 struct sm_state *sm;
1706 const char *param_name;
1707 char *compare_str;
1708 char buf[256];
1709
1710 returned_sym = expr_to_sym(expr);
1711 if (!returned_sym)
1712 return;
1713
1714 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1715 if (!estate_rl(sm->state))
1716 continue;
1717 if (returned_sym != sm->sym)
1718 continue;
1719
1720 param_name = get_param_name(sm);
1721 if (!param_name)
1722 continue;
1723 if (strcmp(param_name, "$") == 0)
1724 continue;
1725 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
1726 if (!compare_str && estate_is_whole(sm->state))
1727 continue;
1728 snprintf(buf, sizeof(buf), "%s%s", sm->state->name, compare_str ?: "");
1729
1730 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
1731 -1, param_name, buf);
1732 } END_FOR_EACH_SM(sm);
1733 }
1734
1735 static void db_limited_before(void)
1736 {
1737 unmatched_stree = clone_stree(__get_cur_stree());
1738 }
1739
1740 static void db_limited_after(void)
1741 {
1742 free_stree(&unmatched_stree);
1743 }
1744
1745 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
1746 {
1747 struct expression *arg;
1748 char *name;
1749 struct symbol *sym;
1750 struct sm_state *sm;
1751 struct symbol *compare_type, *var_type;
1752 struct range_list *rl;
1753 struct range_list *limit;
1754 struct range_list *new;
1755
1756 while (expr->type == EXPR_ASSIGNMENT)
1757 expr = strip_expr(expr->right);
1758 if (expr->type != EXPR_CALL)
1759 return;
1760
1761 arg = get_argument_from_call_expr(expr->args, param);
1762 if (!arg)
1763 return;
1764
1765 name = get_variable_from_key(arg, key, &sym);
1766 if (!name || !sym)
1767 goto free;
1768
1769 if (strcmp(key, "$") == 0)
1770 compare_type = get_arg_type(expr->fn, param);
1771 else
1772 compare_type = get_member_type_from_key(arg, key);
1773
1774 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1775 if (sm)
1776 rl = estate_rl(sm->state);
1777 else
1778 rl = alloc_whole_rl(compare_type);
1779
1780 call_results_to_rl(expr, compare_type, value, &limit);
1781 new = rl_intersection(rl, limit);
1782
1783 var_type = get_member_type_from_key(arg, key);
1784 new = cast_rl(var_type, new);
1785
1786 /* We want to preserve the implications here */
1787 if (sm && rl_equiv(estate_rl(sm->state), new))
1788 __set_sm(sm);
1789 else {
1790 if (op == PARAM_LIMIT)
1791 set_extra_nomod(name, sym, alloc_estate_rl(new));
1792 else
1793 set_extra_mod(name, sym, alloc_estate_rl(new));
1794 }
1795
1796 free:
1797 free_string(name);
1798 }
1799
1800 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1801 {
1802 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
1803 }
1804
1805 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1806 {
1807 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
1808 }
1809
1810 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
1811 {
1812 struct expression *arg;
1813 char *name;
1814 struct symbol *sym;
1815 struct symbol *type;
1816 struct smatch_state *state;
1817 struct range_list *new = NULL;
1818 struct range_list *added = NULL;
1819
1820 while (expr->type == EXPR_ASSIGNMENT)
1821 expr = strip_expr(expr->right);
1822 if (expr->type != EXPR_CALL)
1823 return;
1824
1825 arg = get_argument_from_call_expr(expr->args, param);
1826 if (!arg)
1827 return;
1828 type = get_member_type_from_key(arg, key);
1829 name = get_variable_from_key(arg, key, &sym);
1830 if (!name || !sym)
1831 goto free;
1832
1833 state = get_state(SMATCH_EXTRA, name, sym);
1834 if (state)
1835 new = estate_rl(state);
1836
1837 call_results_to_rl(expr, type, value, &added);
1838
1839 if (op == PARAM_SET)
1840 new = added;
1841 else
1842 new = rl_union(new, added);
1843
1844 set_extra_mod(name, sym, alloc_estate_rl(new));
1845 free:
1846 free_string(name);
1847 }
1848
1849 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1850 {
1851 db_param_add_set(expr, param, key, value, PARAM_ADD);
1852 }
1853
1854 static void db_param_set(struct expression *expr, int param, char *key, char *value)
1855 {
1856 db_param_add_set(expr, param, key, value, PARAM_SET);
1857 }
1858
1859 static void db_param_value(struct expression *expr, int param, char *key, char *value)
1860 {
1861 struct expression *call;
1862 char *name;
1863 struct symbol *sym;
1864 struct symbol *type;
1865 struct range_list *rl = NULL;
1866
1867 if (param != -1)
1868 return;
1869
1870 call = expr;
1871 while (call->type == EXPR_ASSIGNMENT)
1872 call = strip_expr(call->right);
1873 if (call->type != EXPR_CALL)
1874 return;
1875
1876 type = get_member_type_from_key(expr->left, key);
1877 name = get_variable_from_key(expr->left, key, &sym);
1878 if (!name || !sym)
1879 goto free;
1880
1881 call_results_to_rl(call, type, value, &rl);
1882
1883 set_extra_mod(name, sym, alloc_estate_rl(rl));
1884 free:
1885 free_string(name);
1886 }
1887
1888 static void match_call_info(struct expression *expr)
1889 {
1890 struct smatch_state *state;
1891 struct range_list *rl = NULL;
1892 struct expression *arg;
1893 struct symbol *type;
1894 int i = 0;
1895
1896 FOR_EACH_PTR(expr->args, arg) {
1897 type = get_arg_type(expr->fn, i);
1898
1899 if (get_implied_rl(arg, &rl))
1900 rl = cast_rl(type, rl);
1901 else
1902 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1903
1904 if (!is_whole_rl(rl))
1905 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
1906 state = get_state_expr(SMATCH_EXTRA, arg);
1907 if (estate_has_fuzzy_max(state)) {
1908 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
1909 sval_to_str(estate_get_fuzzy_max(state)));
1910 }
1911 i++;
1912 } END_FOR_EACH_PTR(arg);
1913 }
1914
1915 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1916 {
1917 struct range_list *rl = NULL;
1918 struct smatch_state *state;
1919 struct symbol *type;
1920 char fullname[256];
1921
1922 if (strcmp(key, "*$") == 0)
1923 snprintf(fullname, sizeof(fullname), "*%s", name);
1924 else if (strncmp(key, "$", 1) == 0)
1925 snprintf(fullname, 256, "%s%s", name, key + 1);
1926 else
1927 return;
1928
1929 type = get_member_type_from_key(symbol_expression(sym), key);
1930 str_to_rl(type, value, &rl);
1931 state = alloc_estate_rl(rl);
1932 set_state(SMATCH_EXTRA, fullname, sym, state);
1933 }
1934
1935 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
1936 {
1937 struct range_list *rl = NULL;
1938 struct smatch_state *state;
1939 struct symbol *type;
1940 char fullname[256];
1941 sval_t max;
1942
1943 if (strcmp(key, "*$") == 0)
1944 snprintf(fullname, sizeof(fullname), "*%s", name);
1945 else if (strncmp(key, "$", 1) == 0)
1946 snprintf(fullname, 256, "%s%s", name, key + 1);
1947 else
1948 return;
1949
1950 state = get_state(SMATCH_EXTRA, fullname, sym);
1951 if (!state)
1952 return;
1953 type = get_member_type_from_key(symbol_expression(sym), key);
1954 str_to_rl(type, value, &rl);
1955 if (!rl_to_sval(rl, &max))
1956 return;
1957 estate_set_fuzzy_max(state, max);
1958 }
1959
1960 struct smatch_state *get_extra_state(struct expression *expr)
1961 {
1962 char *name;
1963 struct symbol *sym;
1964 struct smatch_state *ret = NULL;
1965 struct range_list *rl;
1966
1967 if (is_pointer(expr) && get_address_rl(expr, &rl))
1968 return alloc_estate_rl(rl);
1969
1970 name = expr_to_known_chunk_sym(expr, &sym);
1971 if (!name)
1972 goto free;
1973
1974 ret = get_state(SMATCH_EXTRA, name, sym);
1975 free:
1976 free_string(name);
1977 return ret;
1978 }
1979
1980 void register_smatch_extra(int id)
1981 {
1982 my_id = id;
1983
1984 add_merge_hook(my_id, &merge_estates);
1985 add_unmatched_state_hook(my_id, &unmatched_state);
1986 select_caller_info_hook(set_param_value, PARAM_VALUE);
1987 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
1988 select_return_states_before(&db_limited_before);
1989 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
1990 select_return_states_hook(PARAM_FILTER, &db_param_filter);
1991 select_return_states_hook(PARAM_ADD, &db_param_add);
1992 select_return_states_hook(PARAM_SET, &db_param_set);
1993 select_return_states_hook(PARAM_VALUE, &db_param_value);
1994 select_return_states_after(&db_limited_after);
1995 }
1996
1997 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
1998 {
1999 struct var_sym_list *links;
2000 struct var_sym *tmp;
2001 struct smatch_state *state;
2002
2003 links = sm->state->data;
2004
2005 FOR_EACH_PTR(links, tmp) {
2006 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2007 if (!state)
2008 continue;
2009 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2010 } END_FOR_EACH_PTR(tmp);
2011 set_state(link_id, sm->name, sm->sym, &undefined);
2012 }
2013
2014 void register_smatch_extra_links(int id)
2015 {
2016 link_id = id;
2017 }
2018
2019 void register_smatch_extra_late(int id)
2020 {
2021 add_merge_hook(link_id, &merge_link_states);
2022 add_modification_hook(link_id, &match_link_modify);
2023 add_hook(&match_dereferences, DEREF_HOOK);
2024 add_hook(&match_pointer_as_array, OP_HOOK);
2025 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
2026 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2027 add_hook(&match_assign, ASSIGNMENT_HOOK);
2028 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2029 add_hook(&unop_expr, OP_HOOK);
2030 add_hook(&asm_expr, ASM_HOOK);
2031 add_untracked_param_hook(&match_untracked_array);
2032
2033 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
2034 add_member_info_callback(my_id, struct_member_callback);
2035 add_split_return_callback(&returned_struct_members);
2036
2037 add_hook(&assume_indexes_are_valid, OP_HOOK);
2038 }
Static analysis for C