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states: make debug output more consistent
[smatch.git] / smatch_extra.c
blob5d107e4c8b5b15016658fa04b2b29325ad76e8be
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 var_sym_list *vsl;
165 struct var_sym *vs;
166 char *name;
167 struct symbol *sym;
168 struct sm_state *ret = NULL;
169
170 array = get_array_base(expr);
171
172 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
173 if (!name || !vsl) {
174 clear_array_states(array);
175 goto free;
176 }
177
178 FOR_EACH_PTR(vsl, vs) {
179 store_link(link_id, vs->var, vs->sym, name, sym);
180 } END_FOR_EACH_PTR(vs);
181
182 call_extra_mod_hooks(name, sym, state);
183 ret = set_state(SMATCH_EXTRA, name, sym, state);
184 free:
185 free_string(name);
186 return ret;
187 }
188
189 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
190 {
191 struct symbol *sym;
192 char *name;
193 struct sm_state *ret = NULL;
194
195 if (is_array(expr))
196 return set_extra_array_mod(expr, state);
197
198 expr = strip_expr(expr);
199 name = expr_to_var_sym(expr, &sym);
200 if (!name || !sym)
201 goto free;
202 ret = set_extra_mod(name, sym, state);
203 free:
204 free_string(name);
205 return ret;
206 }
207
208 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
209 {
210 char *new_name;
211 struct symbol *new_sym;
212 struct relation *rel;
213 struct smatch_state *orig_state;
214
215 orig_state = get_state(SMATCH_EXTRA, name, sym);
216
217 new_name = get_other_name_sym(name, sym, &new_sym);
218 if (new_name && new_sym)
219 set_state(SMATCH_EXTRA, new_name, new_sym, state);
220 free_string(new_name);
221
222 if (!estate_related(orig_state)) {
223 set_state(SMATCH_EXTRA, name, sym, state);
224 return;
225 }
226
227 set_related(state, estate_related(orig_state));
228 FOR_EACH_PTR(estate_related(orig_state), rel) {
229 struct smatch_state *estate;
230
231 if (option_debug_related)
232 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
233 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
234 if (!estate)
235 continue;
236 set_state(SMATCH_EXTRA, rel->name, rel->sym, clone_estate_cast(estate_type(estate), 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 (!true_state && !false_state)
267 return;
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 (!true_state && !false_state)
335 return;
336
337 if (get_value(expr, &sval))
338 return;
339
340 expr = strip_expr(expr);
341 name = expr_to_var_sym(expr, &sym);
342 if (!name || !sym) {
343 free_string(name);
344 set_extra_chunk_true_false(expr, true_state, false_state);
345 return;
346 }
347 set_extra_true_false(name, sym, true_state, false_state);
348 free_string(name);
349 }
350
351 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
352 {
353 struct expression *iter_var;
354 struct expression *condition;
355 struct sm_state *sm;
356 struct smatch_state *estate;
357 sval_t start;
358
359 condition = strip_expr(loop->iterator_pre_condition);
360 if (!condition)
361 return NULL;
362 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
363 return NULL;
364 if (condition->op != SPECIAL_DECREMENT)
365 return NULL;
366
367 iter_var = condition->unop;
368 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
369 if (!sm)
370 return NULL;
371 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
372 return NULL;
373 start = estate_max(sm->state);
374 if (sval_cmp_val(start, 0) <= 0)
375 return NULL;
376 if (!sval_is_max(start))
377 start.value--;
378
379 if (condition->type == EXPR_PREOP) {
380 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
381 if (estate_has_hard_max(sm->state))
382 estate_set_hard_max(estate);
383 estate_copy_fuzzy_max(estate, sm->state);
384 set_extra_expr_mod(iter_var, estate);
385 }
386 if (condition->type == EXPR_POSTOP) {
387 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
388 if (estate_has_hard_max(sm->state))
389 estate_set_hard_max(estate);
390 estate_copy_fuzzy_max(estate, sm->state);
391 set_extra_expr_mod(iter_var, estate);
392 }
393 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
394 }
395
396 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
397 struct expression *condition)
398 {
399 struct expression *iter_var;
400 struct sm_state *sm;
401 struct smatch_state *estate;
402 sval_t start, end, max;
403
404 iter_var = iter_expr->unop;
405 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
406 if (!sm)
407 return NULL;
408 if (!estate_get_single_value(sm->state, &start))
409 return NULL;
410 if (get_implied_max(condition->right, &end))
411 end = sval_cast(get_type(iter_var), end);
412 else
413 end = sval_type_max(get_type(iter_var));
414
415 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
416 return NULL;
417
418 switch (condition->op) {
419 case SPECIAL_UNSIGNED_LT:
420 case SPECIAL_NOTEQUAL:
421 case '<':
422 if (!sval_is_min(end))
423 end.value--;
424 break;
425 case SPECIAL_UNSIGNED_LTE:
426 case SPECIAL_LTE:
427 break;
428 default:
429 return NULL;
430 }
431 if (sval_cmp(end, start) < 0)
432 return NULL;
433 estate = alloc_estate_range(start, end);
434 if (get_hard_max(condition->right, &max)) {
435 estate_set_hard_max(estate);
436 if (condition->op == '<' ||
437 condition->op == SPECIAL_UNSIGNED_LT ||
438 condition->op == SPECIAL_NOTEQUAL)
439 max.value--;
440 estate_set_fuzzy_max(estate, max);
441 }
442 set_extra_expr_mod(iter_var, estate);
443 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
444 }
445
446 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
447 struct expression *condition)
448 {
449 struct expression *iter_var;
450 struct sm_state *sm;
451 struct smatch_state *estate;
452 sval_t start, end;
453
454 iter_var = iter_expr->unop;
455 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
456 if (!sm)
457 return NULL;
458 if (!estate_get_single_value(sm->state, &start))
459 return NULL;
460 if (!get_implied_min(condition->right, &end))
461 end = sval_type_min(get_type(iter_var));
462 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
463 return NULL;
464
465 switch (condition->op) {
466 case SPECIAL_NOTEQUAL:
467 case '>':
468 if (!sval_is_min(end) && !sval_is_max(end))
469 end.value++;
470 break;
471 case SPECIAL_GTE:
472 break;
473 default:
474 return NULL;
475 }
476 if (sval_cmp(end, start) > 0)
477 return NULL;
478 estate = alloc_estate_range(end, start);
479 estate_set_hard_max(estate);
480 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
481 set_extra_expr_mod(iter_var, estate);
482 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
483 }
484
485 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
486 {
487 struct expression *iter_expr;
488 struct expression *condition;
489
490 if (!loop->iterator_post_statement)
491 return NULL;
492 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
493 return NULL;
494 iter_expr = loop->iterator_post_statement->expression;
495 if (!loop->iterator_pre_condition)
496 return NULL;
497 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
498 return NULL;
499 condition = loop->iterator_pre_condition;
500
501 if (iter_expr->op == SPECIAL_INCREMENT)
502 return handle_canonical_for_inc(iter_expr, condition);
503 if (iter_expr->op == SPECIAL_DECREMENT)
504 return handle_canonical_for_dec(iter_expr, condition);
505 return NULL;
506 }
507
508 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
509 {
510 struct sm_state *ret;
511
512 __push_fake_cur_stree();
513 if (!loop->iterator_post_statement)
514 ret = handle_canonical_while_count_down(loop);
515 else
516 ret = handle_canonical_for_loops(loop);
517 *stree = __pop_fake_cur_stree();
518 return ret;
519 }
520
521 int __iterator_unchanged(struct sm_state *sm)
522 {
523 if (!sm)
524 return 0;
525 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
526 return 1;
527 return 0;
528 }
529
530 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
531 {
532 sval_t after_value;
533
534 /* paranoid checking. prolly not needed */
535 condition = strip_expr(condition);
536 if (!condition)
537 return;
538 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
539 return;
540 if (condition->op != SPECIAL_DECREMENT)
541 return;
542 after_value = estate_min(sm->state);
543 after_value.value--;
544 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
545 }
546
547 void __extra_pre_loop_hook_after(struct sm_state *sm,
548 struct statement *iterator,
549 struct expression *condition)
550 {
551 struct expression *iter_expr;
552 sval_t limit;
553 struct smatch_state *state;
554
555 if (!iterator) {
556 while_count_down_after(sm, condition);
557 return;
558 }
559
560 iter_expr = iterator->expression;
561
562 if (condition->type != EXPR_COMPARE)
563 return;
564 if (iter_expr->op == SPECIAL_INCREMENT) {
565 limit = sval_binop(estate_max(sm->state), '+',
566 sval_type_val(estate_type(sm->state), 1));
567 } else {
568 limit = sval_binop(estate_min(sm->state), '-',
569 sval_type_val(estate_type(sm->state), 1));
570 }
571 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
572 if (iter_expr->op == SPECIAL_INCREMENT)
573 state = alloc_estate_range(estate_min(sm->state), limit);
574 else
575 state = alloc_estate_range(limit, estate_max(sm->state));
576 } else {
577 state = alloc_estate_sval(limit);
578 }
579 if (!estate_has_hard_max(sm->state)) {
580 estate_clear_hard_max(state);
581 }
582 if (estate_has_fuzzy_max(sm->state)) {
583 sval_t hmax = estate_get_fuzzy_max(sm->state);
584 sval_t max = estate_max(sm->state);
585
586 if (sval_cmp(hmax, max) != 0)
587 estate_clear_fuzzy_max(state);
588 } else if (!estate_has_fuzzy_max(sm->state)) {
589 estate_clear_fuzzy_max(state);
590 }
591
592 set_extra_mod(sm->name, sm->sym, state);
593 }
594
595 static struct stree *unmatched_stree;
596 static struct smatch_state *unmatched_state(struct sm_state *sm)
597 {
598 struct smatch_state *state;
599
600 if (unmatched_stree) {
601 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
602 if (state)
603 return state;
604 }
605 if (parent_is_gone_var_sym(sm->name, sm->sym))
606 return alloc_estate_empty();
607 return alloc_estate_whole(estate_type(sm->state));
608 }
609
610 static void clear_the_pointed_at(struct expression *expr)
611 {
612 struct stree *stree;
613 char *name;
614 struct symbol *sym;
615 struct sm_state *tmp;
616
617 name = expr_to_var_sym(expr, &sym);
618 if (!name || !sym)
619 goto free;
620
621 stree = __get_cur_stree();
622 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
623 if (tmp->name[0] != '*')
624 continue;
625 if (tmp->sym != sym)
626 continue;
627 if (strcmp(tmp->name + 1, name) != 0)
628 continue;
629 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
630 } END_FOR_EACH_SM(tmp);
631
632 free:
633 free_string(name);
634 }
635
636 static void match_function_call(struct expression *expr)
637 {
638 struct expression *arg;
639 struct expression *tmp;
640
641 /* if we have the db this is handled in smatch_function_hooks.c */
642 if (!option_no_db)
643 return;
644 if (inlinable(expr->fn))
645 return;
646
647 FOR_EACH_PTR(expr->args, arg) {
648 tmp = strip_expr(arg);
649 if (tmp->type == EXPR_PREOP && tmp->op == '&')
650 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
651 else
652 clear_the_pointed_at(tmp);
653 } END_FOR_EACH_PTR(arg);
654 }
655
656 static int values_fit_type(struct expression *left, struct expression *right)
657 {
658 struct range_list *rl;
659 struct symbol *type;
660
661 type = get_type(left);
662 if (!type)
663 return 0;
664 get_absolute_rl(right, &rl);
665 if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
666 return 0;
667 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
668 return 0;
669 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
670 return 0;
671 return 1;
672 }
673
674 static void save_chunk_info(struct expression *left, struct expression *right)
675 {
676 struct var_sym_list *vsl;
677 struct var_sym *vs;
678 struct expression *add_expr;
679 struct symbol *type;
680 sval_t sval;
681 char *name;
682 struct symbol *sym;
683
684 if (right->type != EXPR_BINOP || right->op != '-')
685 return;
686 if (!get_value(right->left, &sval))
687 return;
688 if (!expr_to_sym(right->right))
689 return;
690
691 add_expr = binop_expression(left, '+', right->right);
692 type = get_type(add_expr);
693 if (!type)
694 return;
695 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
696 if (!name || !vsl)
697 goto free;
698 FOR_EACH_PTR(vsl, vs) {
699 store_link(link_id, vs->var, vs->sym, name, sym);
700 } END_FOR_EACH_PTR(vs);
701
702 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
703 free:
704 free_string(name);
705 }
706
707 static void do_array_assign(struct expression *left, int op, struct expression *right)
708 {
709 struct range_list *rl;
710
711 if (op == '=') {
712 get_absolute_rl(right, &rl);
713 rl = cast_rl(get_type(left), rl);
714 } else {
715 rl = alloc_whole_rl(get_type(left));
716 }
717
718 set_extra_array_mod(left, alloc_estate_rl(rl));
719 }
720
721 static void match_untracked_array(struct expression *call, int param)
722 {
723 struct expression *arg;
724
725 arg = get_argument_from_call_expr(call->args, param);
726 arg = strip_expr(arg);
727
728 clear_array_states(arg);
729 }
730
731 static void match_vanilla_assign(struct expression *left, struct expression *right)
732 {
733 struct range_list *orig_rl = NULL;
734 struct range_list *rl = NULL;
735 struct symbol *right_sym;
736 struct symbol *left_type;
737 struct symbol *right_type;
738 char *right_name = NULL;
739 struct symbol *sym;
740 char *name;
741 sval_t max;
742 struct smatch_state *state;
743 int comparison;
744
745 if (is_struct(left))
746 return;
747
748 save_chunk_info(left, right);
749
750 name = expr_to_var_sym(left, &sym);
751 if (!name) {
752 if (is_array(left))
753 do_array_assign(left, '=', right);
754 return;
755 }
756
757 left_type = get_type(left);
758 right_type = get_type(right);
759
760 right_name = expr_to_var_sym(right, &right_sym);
761
762 if (!__in_fake_assign &&
763 !(right->type == EXPR_PREOP && right->op == '&') &&
764 right_name && right_sym &&
765 values_fit_type(left, right) &&
766 !has_symbol(right, sym)) {
767 set_equiv(left, right);
768 goto free;
769 }
770
771 if (is_pointer(right) && get_address_rl(right, &rl)) {
772 state = alloc_estate_rl(rl);
773 goto done;
774 }
775
776 comparison = get_comparison(left, right);
777 if (comparison) {
778 comparison = flip_comparison(comparison);
779 get_implied_rl(left, &orig_rl);
780 }
781
782 if (get_implied_rl(right, &rl)) {
783 rl = cast_rl(left_type, rl);
784 if (orig_rl)
785 filter_by_comparison(&rl, comparison, orig_rl);
786 state = alloc_estate_rl(rl);
787 if (get_hard_max(right, &max)) {
788 estate_set_hard_max(state);
789 estate_set_fuzzy_max(state, max);
790 }
791 } else {
792 rl = alloc_whole_rl(right_type);
793 rl = cast_rl(left_type, rl);
794 if (orig_rl)
795 filter_by_comparison(&rl, comparison, orig_rl);
796 state = alloc_estate_rl(rl);
797 }
798
799 done:
800 set_extra_mod(name, sym, state);
801 free:
802 free_string(right_name);
803 }
804
805 static int op_remove_assign(int op)
806 {
807 switch (op) {
808 case SPECIAL_ADD_ASSIGN:
809 return '+';
810 case SPECIAL_SUB_ASSIGN:
811 return '-';
812 case SPECIAL_MUL_ASSIGN:
813 return '*';
814 case SPECIAL_DIV_ASSIGN:
815 return '/';
816 case SPECIAL_MOD_ASSIGN:
817 return '%';
818 case SPECIAL_AND_ASSIGN:
819 return '&';
820 case SPECIAL_OR_ASSIGN:
821 return '|';
822 case SPECIAL_XOR_ASSIGN:
823 return '^';
824 case SPECIAL_SHL_ASSIGN:
825 return SPECIAL_LEFTSHIFT;
826 case SPECIAL_SHR_ASSIGN:
827 return SPECIAL_RIGHTSHIFT;
828 default:
829 return op;
830 }
831 }
832
833 static void match_assign(struct expression *expr)
834 {
835 struct range_list *rl = NULL;
836 struct expression *left;
837 struct expression *right;
838 struct expression *binop_expr;
839 struct symbol *left_type;
840 struct symbol *right_type;
841 struct symbol *sym;
842 char *name;
843 sval_t left_min, left_max;
844 sval_t right_min, right_max;
845 sval_t res_min, res_max;
846
847 left = strip_expr(expr->left);
848
849 right = strip_parens(expr->right);
850 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
851 right = get_argument_from_call_expr(right->args, 0);
852 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
853 right = strip_parens(right->left);
854
855 if (expr->op == '=' && is_condition(expr->right))
856 return; /* handled in smatch_condition.c */
857 if (expr->op == '=' && right->type == EXPR_CALL)
858 return; /* handled in smatch_function_hooks.c */
859 if (expr->op == '=') {
860 match_vanilla_assign(left, right);
861 return;
862 }
863
864 name = expr_to_var_sym(left, &sym);
865 if (!name)
866 return;
867
868 left_type = get_type(left);
869 right_type = get_type(right);
870
871 res_min = sval_type_min(left_type);
872 res_max = sval_type_max(left_type);
873
874 switch (expr->op) {
875 case SPECIAL_ADD_ASSIGN:
876 get_absolute_max(left, &left_max);
877 get_absolute_max(right, &right_max);
878 if (sval_binop_overflows(left_max, '+', right_max))
879 break;
880 if (get_implied_min(left, &left_min) &&
881 !sval_is_negative_min(left_min) &&
882 get_implied_min(right, &right_min) &&
883 !sval_is_negative_min(right_min)) {
884 res_min = sval_binop(left_min, '+', right_min);
885 res_min = sval_cast(right_type, res_min);
886 }
887 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
888 break;
889 res_max = sval_binop(left_max, '+', right_max);
890 res_max = sval_cast(right_type, res_max);
891 break;
892 case SPECIAL_SUB_ASSIGN:
893 if (get_implied_max(left, &left_max) &&
894 !sval_is_max(left_max) &&
895 get_implied_min(right, &right_min) &&
896 !sval_is_min(right_min)) {
897 res_max = sval_binop(left_max, '-', right_min);
898 res_max = sval_cast(right_type, res_max);
899 }
900 if (inside_loop())
901 break;
902 if (get_implied_min(left, &left_min) &&
903 !sval_is_min(left_min) &&
904 get_implied_max(right, &right_max) &&
905 !sval_is_max(right_max)) {
906 res_min = sval_binop(left_min, '-', right_max);
907 res_min = sval_cast(right_type, res_min);
908 }
909 break;
910 case SPECIAL_AND_ASSIGN:
911 case SPECIAL_MOD_ASSIGN:
912 case SPECIAL_SHL_ASSIGN:
913 case SPECIAL_SHR_ASSIGN:
914 case SPECIAL_OR_ASSIGN:
915 case SPECIAL_XOR_ASSIGN:
916 case SPECIAL_MUL_ASSIGN:
917 case SPECIAL_DIV_ASSIGN:
918 binop_expr = binop_expression(expr->left,
919 op_remove_assign(expr->op),
920 expr->right);
921 if (get_absolute_rl(binop_expr, &rl)) {
922 rl = cast_rl(left_type, rl);
923 set_extra_mod(name, sym, alloc_estate_rl(rl));
924 goto free;
925 }
926 break;
927 }
928 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
929 set_extra_mod(name, sym, alloc_estate_rl(rl));
930 free:
931 free_string(name);
932 }
933
934 static struct smatch_state *increment_state(struct smatch_state *state)
935 {
936 sval_t min = estate_min(state);
937 sval_t max = estate_max(state);
938
939 if (!estate_rl(state))
940 return NULL;
941
942 if (inside_loop())
943 max = sval_type_max(max.type);
944
945 if (!sval_is_min(min) && !sval_is_max(min))
946 min.value++;
947 if (!sval_is_min(max) && !sval_is_max(max))
948 max.value++;
949 return alloc_estate_range(min, max);
950 }
951
952 static struct smatch_state *decrement_state(struct smatch_state *state)
953 {
954 sval_t min = estate_min(state);
955 sval_t max = estate_max(state);
956
957 if (!estate_rl(state))
958 return NULL;
959
960 if (inside_loop())
961 min = sval_type_min(min.type);
962
963 if (!sval_is_min(min) && !sval_is_max(min))
964 min.value--;
965 if (!sval_is_min(max) && !sval_is_max(max))
966 max.value--;
967 return alloc_estate_range(min, max);
968 }
969
970 static void unop_expr(struct expression *expr)
971 {
972 struct smatch_state *state;
973
974 if (expr->smatch_flags & Handled)
975 return;
976
977 switch (expr->op) {
978 case SPECIAL_INCREMENT:
979 state = get_state_expr(SMATCH_EXTRA, expr->unop);
980 state = increment_state(state);
981 if (!state)
982 state = alloc_estate_whole(get_type(expr));
983 set_extra_expr_mod(expr->unop, state);
984 break;
985 case SPECIAL_DECREMENT:
986 state = get_state_expr(SMATCH_EXTRA, expr->unop);
987 state = decrement_state(state);
988 if (!state)
989 state = alloc_estate_whole(get_type(expr));
990 set_extra_expr_mod(expr->unop, state);
991 break;
992 default:
993 return;
994 }
995 }
996
997 static void asm_expr(struct statement *stmt)
998 {
999
1000 struct expression *expr;
1001 struct symbol *type;
1002 int state = 0;
1003
1004 FOR_EACH_PTR(stmt->asm_outputs, expr) {
1005 switch (state) {
1006 case 0: /* identifier */
1007 case 1: /* constraint */
1008 state++;
1009 continue;
1010 case 2: /* expression */
1011 state = 0;
1012 type = get_type(strip_expr(expr));
1013 set_extra_expr_mod(expr, alloc_estate_whole(type));
1014 continue;
1015 }
1016 } END_FOR_EACH_PTR(expr);
1017 }
1018
1019 static void check_dereference(struct expression *expr)
1020 {
1021 if (outside_of_function())
1022 return;
1023 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1024 }
1025
1026 static void match_dereferences(struct expression *expr)
1027 {
1028 if (expr->type != EXPR_PREOP)
1029 return;
1030 check_dereference(expr->unop);
1031 }
1032
1033 static void match_pointer_as_array(struct expression *expr)
1034 {
1035 if (!is_array(expr))
1036 return;
1037 check_dereference(get_array_base(expr));
1038 }
1039
1040 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
1041 {
1042 struct symbol *sym;
1043 char *name;
1044
1045 name = get_variable_from_key(arg, key, &sym);
1046 if (!name || !sym)
1047 goto free;
1048
1049 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1050
1051 free:
1052 free_string(name);
1053 }
1054
1055 static sval_t add_one(sval_t sval)
1056 {
1057 sval.value++;
1058 return sval;
1059 }
1060
1061 static sval_t sub_one(sval_t sval)
1062 {
1063 sval.value--;
1064 return sval;
1065 }
1066
1067 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1068 {
1069 struct statement *stmt;
1070 struct expression *cond;
1071 struct smatch_state *true_state, *false_state;
1072 sval_t start;
1073 sval_t limit;
1074
1075 /*
1076 * If we're decrementing here then that's a canonical while count down
1077 * so it's handled already. We're only handling loops like:
1078 * i = 0;
1079 * do { ... } while (i++ < 3);
1080 */
1081
1082 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1083 return 0;
1084
1085 stmt = __cur_stmt->parent;
1086 if (!stmt)
1087 return 0;
1088 if (stmt->type == STMT_COMPOUND)
1089 stmt = stmt->parent;
1090 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1091 return 0;
1092
1093 cond = strip_expr(stmt->iterator_post_condition);
1094 if (cond->type != EXPR_COMPARE || cond->op != op)
1095 return 0;
1096 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1097 return 0;
1098
1099 if (!get_implied_value(left->unop, &start))
1100 return 0;
1101 if (!get_implied_value(right, &limit))
1102 return 0;
1103
1104 if (sval_cmp(start, limit) > 0)
1105 return 0;
1106
1107 switch (op) {
1108 case '<':
1109 case SPECIAL_UNSIGNED_LT:
1110 break;
1111 case SPECIAL_LTE:
1112 case SPECIAL_UNSIGNED_LTE:
1113 limit = add_one(limit);
1114 default:
1115 return 0;
1116
1117 }
1118
1119 true_state = alloc_estate_range(add_one(start), limit);
1120 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1121
1122 /* Currently we just discard the false state but when two passes is
1123 * implimented correctly then it will use it.
1124 */
1125
1126 set_extra_expr_true_false(left->unop, true_state, false_state);
1127
1128 return 1;
1129 }
1130
1131 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1132 {
1133 struct range_list *left_orig;
1134 struct range_list *left_true;
1135 struct range_list *left_false;
1136 struct range_list *right_orig;
1137 struct range_list *right_true;
1138 struct range_list *right_false;
1139 struct smatch_state *left_true_state;
1140 struct smatch_state *left_false_state;
1141 struct smatch_state *right_true_state;
1142 struct smatch_state *right_false_state;
1143 sval_t min, max, dummy, hard_max;
1144 int left_postop = 0;
1145 int right_postop = 0;
1146
1147 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1148 if (left->type == EXPR_POSTOP) {
1149 left->smatch_flags |= Handled;
1150 left_postop = left->op;
1151 if (handle_postop_inc(left, op, right))
1152 return;
1153 }
1154 left = strip_parens(left->unop);
1155 }
1156 while (left->type == EXPR_ASSIGNMENT)
1157 left = strip_parens(left->left);
1158
1159 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1160 if (right->type == EXPR_POSTOP) {
1161 right->smatch_flags |= Handled;
1162 right_postop = right->op;
1163 }
1164 right = strip_parens(right->unop);
1165 }
1166
1167 /* FIXME: we should be able to use get_real_absolute_rl() here but
1168 * apparently that is buggy.
1169 */
1170 get_real_absolute_rl(left, &left_orig);
1171 left_orig = cast_rl(type, left_orig);
1172
1173 get_real_absolute_rl(right, &right_orig);
1174 right_orig = cast_rl(type, right_orig);
1175
1176 min = sval_type_min(type);
1177 max = sval_type_max(type);
1178
1179 left_true = clone_rl(left_orig);
1180 left_false = clone_rl(left_orig);
1181 right_true = clone_rl(right_orig);
1182 right_false = clone_rl(right_orig);
1183
1184 switch (op) {
1185 case '<':
1186 case SPECIAL_UNSIGNED_LT:
1187 left_true = remove_range(left_orig, rl_max(right_orig), max);
1188 if (!sval_is_min(rl_min(right_orig))) {
1189 left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1190 }
1191
1192 right_true = remove_range(right_orig, min, rl_min(left_orig));
1193 if (!sval_is_max(rl_max(left_orig)))
1194 right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1195 break;
1196 case SPECIAL_UNSIGNED_LTE:
1197 case SPECIAL_LTE:
1198 if (!sval_is_max(rl_max(right_orig)))
1199 left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1200 left_false = remove_range(left_orig, min, rl_min(right_orig));
1201
1202 if (!sval_is_min(rl_min(left_orig)))
1203 right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1204 right_false = remove_range(right_orig, rl_max(left_orig), max);
1205
1206 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1207 left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
1208 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1209 right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
1210 break;
1211 case SPECIAL_EQUAL:
1212 if (!sval_is_max(rl_max(right_orig))) {
1213 left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
1214 }
1215 if (!sval_is_min(rl_min(right_orig))) {
1216 left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
1217 }
1218 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1219 left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1220
1221 if (!sval_is_max(rl_max(left_orig)))
1222 right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
1223 if (!sval_is_min(rl_min(left_orig)))
1224 right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
1225 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1226 right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1227 break;
1228 case SPECIAL_UNSIGNED_GTE:
1229 case SPECIAL_GTE:
1230 if (!sval_is_min(rl_min(right_orig)))
1231 left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
1232 left_false = remove_range(left_orig, rl_max(right_orig), max);
1233
1234 if (!sval_is_max(rl_max(left_orig)))
1235 right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
1236 right_false = remove_range(right_orig, min, rl_min(left_orig));
1237
1238 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1239 right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
1240 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1241 left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
1242 break;
1243 case '>':
1244 case SPECIAL_UNSIGNED_GT:
1245 left_true = remove_range(left_orig, min, rl_min(right_orig));
1246 if (!sval_is_max(rl_max(right_orig)))
1247 left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1248
1249 right_true = remove_range(right_orig, rl_max(left_orig), max);
1250 if (!sval_is_min(rl_min(left_orig)))
1251 right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1252 break;
1253 case SPECIAL_NOTEQUAL:
1254 if (!sval_is_max(rl_max(right_orig)))
1255 left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
1256 if (!sval_is_min(rl_min(right_orig)))
1257 left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
1258 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1259 left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1260
1261 if (!sval_is_max(rl_max(left_orig)))
1262 right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
1263 if (!sval_is_min(rl_min(left_orig)))
1264 right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
1265 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1266 right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1267 break;
1268 default:
1269 return;
1270 }
1271
1272 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1273 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1274 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1275 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1276
1277 left_true_state = alloc_estate_rl(left_true);
1278 left_false_state = alloc_estate_rl(left_false);
1279 right_true_state = alloc_estate_rl(right_true);
1280 right_false_state = alloc_estate_rl(right_false);
1281
1282 switch (op) {
1283 case '<':
1284 case SPECIAL_UNSIGNED_LT:
1285 case SPECIAL_UNSIGNED_LTE:
1286 case SPECIAL_LTE:
1287 if (get_hard_max(right, &dummy))
1288 estate_set_hard_max(left_true_state);
1289 if (get_hard_max(left, &dummy))
1290 estate_set_hard_max(right_false_state);
1291 break;
1292 case '>':
1293 case SPECIAL_UNSIGNED_GT:
1294 case SPECIAL_UNSIGNED_GTE:
1295 case SPECIAL_GTE:
1296 if (get_hard_max(left, &dummy))
1297 estate_set_hard_max(right_true_state);
1298 if (get_hard_max(right, &dummy))
1299 estate_set_hard_max(left_false_state);
1300 break;
1301 }
1302
1303 switch (op) {
1304 case '<':
1305 case SPECIAL_UNSIGNED_LT:
1306 case SPECIAL_UNSIGNED_LTE:
1307 case SPECIAL_LTE:
1308 if (get_hard_max(right, &hard_max)) {
1309 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1310 hard_max.value--;
1311 estate_set_fuzzy_max(left_true_state, hard_max);
1312 }
1313 if (get_implied_value(right, &hard_max)) {
1314 if (op == SPECIAL_UNSIGNED_LTE ||
1315 op == SPECIAL_LTE)
1316 hard_max.value++;
1317 estate_set_fuzzy_max(left_false_state, hard_max);
1318 }
1319 if (get_hard_max(left, &hard_max)) {
1320 if (op == SPECIAL_UNSIGNED_LTE ||
1321 op == SPECIAL_LTE)
1322 hard_max.value--;
1323 estate_set_fuzzy_max(right_false_state, hard_max);
1324 }
1325 if (get_implied_value(left, &hard_max)) {
1326 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1327 hard_max.value++;
1328 estate_set_fuzzy_max(right_true_state, hard_max);
1329 }
1330 break;
1331 case '>':
1332 case SPECIAL_UNSIGNED_GT:
1333 case SPECIAL_UNSIGNED_GTE:
1334 case SPECIAL_GTE:
1335 if (get_hard_max(left, &hard_max)) {
1336 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1337 hard_max.value--;
1338 estate_set_fuzzy_max(right_true_state, hard_max);
1339 }
1340 if (get_implied_value(left, &hard_max)) {
1341 if (op == SPECIAL_UNSIGNED_GTE ||
1342 op == SPECIAL_GTE)
1343 hard_max.value++;
1344 estate_set_fuzzy_max(right_false_state, hard_max);
1345 }
1346 if (get_hard_max(right, &hard_max)) {
1347 if (op == SPECIAL_UNSIGNED_LTE ||
1348 op == SPECIAL_LTE)
1349 hard_max.value--;
1350 estate_set_fuzzy_max(left_false_state, hard_max);
1351 }
1352 if (get_implied_value(right, &hard_max)) {
1353 if (op == '>' ||
1354 op == SPECIAL_UNSIGNED_GT)
1355 hard_max.value++;
1356 estate_set_fuzzy_max(left_true_state, hard_max);
1357 }
1358 break;
1359 case SPECIAL_EQUAL:
1360 if (get_hard_max(left, &hard_max))
1361 estate_set_fuzzy_max(right_true_state, hard_max);
1362 if (get_hard_max(right, &hard_max))
1363 estate_set_fuzzy_max(left_true_state, hard_max);
1364 break;
1365 }
1366
1367 if (get_hard_max(left, &hard_max)) {
1368 estate_set_hard_max(left_true_state);
1369 estate_set_hard_max(left_false_state);
1370 }
1371 if (get_hard_max(right, &hard_max)) {
1372 estate_set_hard_max(right_true_state);
1373 estate_set_hard_max(right_false_state);
1374 }
1375
1376 if (left_postop == SPECIAL_INCREMENT) {
1377 left_true_state = increment_state(left_true_state);
1378 left_false_state = increment_state(left_false_state);
1379 }
1380 if (left_postop == SPECIAL_DECREMENT) {
1381 left_true_state = decrement_state(left_true_state);
1382 left_false_state = decrement_state(left_false_state);
1383 }
1384 if (right_postop == SPECIAL_INCREMENT) {
1385 right_true_state = increment_state(right_true_state);
1386 right_false_state = increment_state(right_false_state);
1387 }
1388 if (right_postop == SPECIAL_DECREMENT) {
1389 right_true_state = decrement_state(right_true_state);
1390 right_false_state = decrement_state(right_false_state);
1391 }
1392
1393 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1394 left_true_state = NULL;
1395 left_false_state = NULL;
1396 }
1397
1398 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1399 right_true_state = NULL;
1400 right_false_state = NULL;
1401 }
1402
1403 set_extra_expr_true_false(left, left_true_state, left_false_state);
1404 set_extra_expr_true_false(right, right_true_state, right_false_state);
1405 }
1406
1407 static int is_simple_math(struct expression *expr)
1408 {
1409 if (!expr)
1410 return 0;
1411 if (expr->type != EXPR_BINOP)
1412 return 0;
1413 switch (expr->op) {
1414 case '+':
1415 case '-':
1416 case '*':
1417 return 1;
1418 }
1419 return 0;
1420 }
1421
1422 static void move_known_values(struct expression **left_p, struct expression **right_p)
1423 {
1424 struct expression *left = *left_p;
1425 struct expression *right = *right_p;
1426 sval_t sval;
1427
1428 if (get_implied_value(left, &sval)) {
1429 if (!is_simple_math(right))
1430 return;
1431 if (right->op == '*') {
1432 sval_t divisor;
1433
1434 if (!get_value(right->right, &divisor))
1435 return;
1436 if (divisor.value == 0 && sval.value % divisor.value)
1437 return;
1438 *left_p = binop_expression(left, invert_op(right->op), right->right);
1439 *right_p = right->left;
1440 return;
1441 }
1442 if (right->op == '+' && get_value(right->left, &sval)) {
1443 *left_p = binop_expression(left, invert_op(right->op), right->left);
1444 *right_p = right->right;
1445 return;
1446 }
1447 if (get_value(right->right, &sval)) {
1448 *left_p = binop_expression(left, invert_op(right->op), right->right);
1449 *right_p = right->left;
1450 return;
1451 }
1452 return;
1453 }
1454 if (get_implied_value(right, &sval)) {
1455 if (!is_simple_math(left))
1456 return;
1457 if (left->op == '*') {
1458 sval_t divisor;
1459
1460 if (!get_value(left->right, &divisor))
1461 return;
1462 if (divisor.value == 0 && sval.value % divisor.value)
1463 return;
1464 *right_p = binop_expression(right, invert_op(left->op), left->right);
1465 *left_p = left->left;
1466 return;
1467 }
1468 if (left->op == '+' && get_value(left->left, &sval)) {
1469 *right_p = binop_expression(right, invert_op(left->op), left->left);
1470 *left_p = left->right;
1471 return;
1472 }
1473
1474 if (get_value(left->right, &sval)) {
1475 *right_p = binop_expression(right, invert_op(left->op), left->right);
1476 *left_p = left->left;
1477 return;
1478 }
1479 return;
1480 }
1481 }
1482
1483 static int match_func_comparison(struct expression *expr)
1484 {
1485 struct expression *left = strip_expr(expr->left);
1486 struct expression *right = strip_expr(expr->right);
1487 sval_t sval;
1488
1489 /*
1490 * fixme: think about this harder. We should always be trying to limit
1491 * the non-call side as well. If we can't determine the limitter does
1492 * that mean we aren't querying the database and are missing important
1493 * information?
1494 */
1495
1496 if (left->type == EXPR_CALL) {
1497 if (get_implied_value(left, &sval)) {
1498 handle_comparison(get_type(expr), left, expr->op, right);
1499 return 1;
1500 }
1501 function_comparison(left, expr->op, right);
1502 return 1;
1503 }
1504
1505 if (right->type == EXPR_CALL) {
1506 if (get_implied_value(right, &sval)) {
1507 handle_comparison(get_type(expr), left, expr->op, right);
1508 return 1;
1509 }
1510 function_comparison(left, expr->op, right);
1511 return 1;
1512 }
1513
1514 return 0;
1515 }
1516
1517 static void match_comparison(struct expression *expr)
1518 {
1519 struct expression *left_orig = strip_parens(expr->left);
1520 struct expression *right_orig = strip_parens(expr->right);
1521 struct expression *left, *right;
1522 struct expression *prev;
1523 struct symbol *type;
1524
1525 if (match_func_comparison(expr))
1526 return;
1527
1528 type = get_type(expr);
1529 if (!type)
1530 type = &llong_ctype;
1531
1532 left = left_orig;
1533 right = right_orig;
1534 move_known_values(&left, &right);
1535 handle_comparison(type, left, expr->op, right);
1536
1537 prev = get_assigned_expr(left_orig);
1538 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1539 left = prev;
1540 right = right_orig;
1541 move_known_values(&left, &right);
1542 handle_comparison(type, left, expr->op, right);
1543 }
1544
1545 prev = get_assigned_expr(right_orig);
1546 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1547 left = left_orig;
1548 right = prev;
1549 move_known_values(&left, &right);
1550 handle_comparison(type, left, expr->op, right);
1551 }
1552 }
1553
1554 static void handle_AND_condition(struct expression *expr)
1555 {
1556 struct range_list *rl = NULL;
1557 sval_t known;
1558
1559 if (get_implied_value(expr->left, &known) && known.value > 0) {
1560 known.value--;
1561 get_absolute_rl(expr->right, &rl);
1562 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1563 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1564 return;
1565 }
1566
1567 if (get_implied_value(expr->right, &known) && known.value > 0) {
1568 known.value--;
1569 get_absolute_rl(expr->left, &rl);
1570 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1571 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1572 return;
1573 }
1574 }
1575
1576 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1577 void __extra_match_condition(struct expression *expr)
1578 {
1579 struct smatch_state *pre_state;
1580 struct smatch_state *true_state;
1581 struct smatch_state *false_state;
1582
1583 expr = strip_expr(expr);
1584 switch (expr->type) {
1585 case EXPR_CALL:
1586 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1587 return;
1588 case EXPR_PREOP:
1589 case EXPR_SYMBOL:
1590 case EXPR_DEREF: {
1591 sval_t zero;
1592
1593 zero = sval_blank(expr);
1594 zero.value = 0;
1595
1596 pre_state = get_extra_state(expr);
1597 true_state = estate_filter_sval(pre_state, zero);
1598 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1599 false_state = alloc_estate_sval(zero);
1600 else
1601 false_state = alloc_estate_empty();
1602 set_extra_expr_true_false(expr, true_state, false_state);
1603 return;
1604 }
1605 case EXPR_COMPARE:
1606 match_comparison(expr);
1607 return;
1608 case EXPR_ASSIGNMENT:
1609 __extra_match_condition(expr->left);
1610 return;
1611 case EXPR_BINOP:
1612 if (expr->op == '&')
1613 handle_AND_condition(expr);
1614 return;
1615 }
1616 }
1617
1618 static void assume_indexes_are_valid(struct expression *expr)
1619 {
1620 struct expression *array_expr;
1621 int array_size;
1622 struct expression *offset;
1623 struct symbol *offset_type;
1624 struct range_list *rl_before;
1625 struct range_list *rl_after;
1626 struct range_list *filter = NULL;
1627 sval_t size;
1628
1629 expr = strip_expr(expr);
1630 if (!is_array(expr))
1631 return;
1632
1633 offset = get_array_offset(expr);
1634 offset_type = get_type(offset);
1635 if (offset_type && type_signed(offset_type)) {
1636 filter = alloc_rl(sval_type_min(offset_type),
1637 sval_type_val(offset_type, -1));
1638 }
1639
1640 array_expr = get_array_base(expr);
1641 array_size = get_real_array_size(array_expr);
1642 if (array_size > 1) {
1643 size = sval_type_val(offset_type, array_size);
1644 add_range(&filter, size, sval_type_max(offset_type));
1645 }
1646
1647 if (!filter)
1648 return;
1649 get_absolute_rl(offset, &rl_before);
1650 rl_after = rl_filter(rl_before, filter);
1651 if (rl_equiv(rl_before, rl_after))
1652 return;
1653 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1654 }
1655
1656 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1657 int implied_not_equal(struct expression *expr, long long val)
1658 {
1659 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1660 }
1661
1662 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1663 {
1664 struct smatch_state *estate;
1665
1666 estate = get_state(SMATCH_EXTRA, name, sym);
1667 if (!estate)
1668 return 0;
1669 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1670 return 1;
1671 return 0;
1672 }
1673
1674 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1675 {
1676 char buf[256];
1677 char *start;
1678 char *end;
1679 struct smatch_state *state;
1680
1681 strncpy(buf, name, sizeof(buf) - 1);
1682 buf[sizeof(buf) - 1] = '\0';
1683
1684 start = &buf[0];
1685 while (*start == '*') {
1686 start++;
1687 state = get_state(SMATCH_EXTRA, start, sym);
1688 if (!state)
1689 continue;
1690 if (!estate_rl(state))
1691 return 1;
1692 if (estate_min(state).value == 0 &&
1693 estate_max(state).value == 0)
1694 return 1;
1695 }
1696
1697 start = &buf[0];
1698 while (*start == '&')
1699 start++;
1700
1701 while ((end = strrchr(start, '-'))) {
1702 *end = '\0';
1703 state = get_state(SMATCH_EXTRA, start, sym);
1704 if (!state)
1705 continue;
1706 if (estate_min(state).value == 0 &&
1707 estate_max(state).value == 0)
1708 return 1;
1709 }
1710 return 0;
1711 }
1712
1713 int parent_is_null(struct expression *expr)
1714 {
1715 struct symbol *sym;
1716 char *var;
1717 int ret = 0;
1718
1719 expr = strip_expr(expr);
1720 var = expr_to_var_sym(expr, &sym);
1721 if (!var || !sym)
1722 goto free;
1723 ret = parent_is_null_var_sym(var, sym);
1724 free:
1725 free_string(var);
1726 return ret;
1727 }
1728
1729 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
1730 {
1731 *(int *)found = 1;
1732 return 0;
1733 }
1734
1735 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1736 {
1737 sval_t sval;
1738 int found = 0;
1739
1740 /* for function pointers assume everything is used */
1741 if (call->fn->type != EXPR_SYMBOL)
1742 return 0;
1743
1744 /*
1745 * kzalloc() information is treated as special because so there is just
1746 * a lot of stuff initialized to zero and it makes building the database
1747 * take hours and hours.
1748 *
1749 * In theory, we should just remove this line and not pass any unused
1750 * information, but I'm not sure enough that this code works so I want
1751 * to hold off on that for now.
1752 */
1753 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
1754 return 0;
1755
1756 run_sql(&param_used_callback, &found,
1757 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
1758 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
1759 if (found)
1760 return 0;
1761
1762 /* If the database is not built yet, then assume everything is used */
1763 run_sql(&param_used_callback, &found,
1764 "select * from call_implies where %s and type = %d;",
1765 get_static_filter(call->fn->symbol), PARAM_USED);
1766 if (!found)
1767 return 0;
1768
1769 return 1;
1770 }
1771
1772 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1773 {
1774 if (estate_is_whole(sm->state))
1775 return;
1776 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
1777 return;
1778 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, sm->state->name);
1779 if (estate_has_fuzzy_max(sm->state))
1780 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1781 sval_to_str(estate_get_fuzzy_max(sm->state)));
1782 }
1783
1784 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
1785 {
1786 struct symbol *returned_sym;
1787 struct sm_state *sm;
1788 const char *param_name;
1789 char *compare_str;
1790 char buf[256];
1791
1792 returned_sym = expr_to_sym(expr);
1793 if (!returned_sym)
1794 return;
1795
1796 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1797 if (!estate_rl(sm->state))
1798 continue;
1799 if (returned_sym != sm->sym)
1800 continue;
1801
1802 param_name = get_param_name(sm);
1803 if (!param_name)
1804 continue;
1805 if (strcmp(param_name, "$") == 0)
1806 continue;
1807 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
1808 if (!compare_str && estate_is_whole(sm->state))
1809 continue;
1810 snprintf(buf, sizeof(buf), "%s%s", sm->state->name, compare_str ?: "");
1811
1812 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
1813 -1, param_name, buf);
1814 } END_FOR_EACH_SM(sm);
1815 }
1816
1817 static void db_limited_before(void)
1818 {
1819 unmatched_stree = clone_stree(__get_cur_stree());
1820 }
1821
1822 static void db_limited_after(void)
1823 {
1824 free_stree(&unmatched_stree);
1825 }
1826
1827 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
1828 {
1829 struct expression *arg;
1830 char *name;
1831 struct symbol *sym;
1832 struct sm_state *sm;
1833 struct symbol *compare_type, *var_type;
1834 struct range_list *rl;
1835 struct range_list *limit;
1836 struct range_list *new;
1837
1838 while (expr->type == EXPR_ASSIGNMENT)
1839 expr = strip_expr(expr->right);
1840 if (expr->type != EXPR_CALL)
1841 return;
1842
1843 arg = get_argument_from_call_expr(expr->args, param);
1844 if (!arg)
1845 return;
1846
1847 name = get_variable_from_key(arg, key, &sym);
1848 if (!name || !sym)
1849 goto free;
1850
1851 if (strcmp(key, "$") == 0)
1852 compare_type = get_arg_type(expr->fn, param);
1853 else
1854 compare_type = get_member_type_from_key(arg, key);
1855
1856 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1857 if (sm)
1858 rl = estate_rl(sm->state);
1859 else
1860 rl = alloc_whole_rl(compare_type);
1861
1862 call_results_to_rl(expr, compare_type, value, &limit);
1863 new = rl_intersection(rl, limit);
1864
1865 var_type = get_member_type_from_key(arg, key);
1866 new = cast_rl(var_type, new);
1867
1868 /* We want to preserve the implications here */
1869 if (sm && rl_equiv(estate_rl(sm->state), new))
1870 __set_sm(sm);
1871 else {
1872 if (op == PARAM_LIMIT)
1873 set_extra_nomod(name, sym, alloc_estate_rl(new));
1874 else
1875 set_extra_mod(name, sym, alloc_estate_rl(new));
1876 }
1877
1878 free:
1879 free_string(name);
1880 }
1881
1882 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1883 {
1884 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
1885 }
1886
1887 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1888 {
1889 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
1890 }
1891
1892 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
1893 {
1894 struct expression *arg;
1895 char *name;
1896 struct symbol *sym;
1897 struct symbol *type;
1898 struct smatch_state *state;
1899 struct range_list *new = NULL;
1900 struct range_list *added = NULL;
1901
1902 while (expr->type == EXPR_ASSIGNMENT)
1903 expr = strip_expr(expr->right);
1904 if (expr->type != EXPR_CALL)
1905 return;
1906
1907 arg = get_argument_from_call_expr(expr->args, param);
1908 if (!arg)
1909 return;
1910 type = get_member_type_from_key(arg, key);
1911 name = get_variable_from_key(arg, key, &sym);
1912 if (!name || !sym)
1913 goto free;
1914
1915 state = get_state(SMATCH_EXTRA, name, sym);
1916 if (state)
1917 new = estate_rl(state);
1918
1919 call_results_to_rl(expr, type, value, &added);
1920
1921 if (op == PARAM_SET)
1922 new = added;
1923 else
1924 new = rl_union(new, added);
1925
1926 set_extra_mod(name, sym, alloc_estate_rl(new));
1927 free:
1928 free_string(name);
1929 }
1930
1931 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1932 {
1933 db_param_add_set(expr, param, key, value, PARAM_ADD);
1934 }
1935
1936 static void db_param_set(struct expression *expr, int param, char *key, char *value)
1937 {
1938 db_param_add_set(expr, param, key, value, PARAM_SET);
1939 }
1940
1941 static void db_param_value(struct expression *expr, int param, char *key, char *value)
1942 {
1943 struct expression *call;
1944 char *name;
1945 struct symbol *sym;
1946 struct symbol *type;
1947 struct range_list *rl = NULL;
1948
1949 if (param != -1)
1950 return;
1951
1952 call = expr;
1953 while (call->type == EXPR_ASSIGNMENT)
1954 call = strip_expr(call->right);
1955 if (call->type != EXPR_CALL)
1956 return;
1957
1958 type = get_member_type_from_key(expr->left, key);
1959 name = get_variable_from_key(expr->left, key, &sym);
1960 if (!name || !sym)
1961 goto free;
1962
1963 call_results_to_rl(call, type, value, &rl);
1964
1965 set_extra_mod(name, sym, alloc_estate_rl(rl));
1966 free:
1967 free_string(name);
1968 }
1969
1970 static void match_call_info(struct expression *expr)
1971 {
1972 struct smatch_state *state;
1973 struct range_list *rl = NULL;
1974 struct expression *arg;
1975 struct symbol *type;
1976 int i = 0;
1977
1978 FOR_EACH_PTR(expr->args, arg) {
1979 type = get_arg_type(expr->fn, i);
1980
1981 if (get_implied_rl(arg, &rl))
1982 rl = cast_rl(type, rl);
1983 else
1984 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1985
1986 if (!is_whole_rl(rl))
1987 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
1988 state = get_state_expr(SMATCH_EXTRA, arg);
1989 if (estate_has_fuzzy_max(state)) {
1990 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
1991 sval_to_str(estate_get_fuzzy_max(state)));
1992 }
1993 i++;
1994 } END_FOR_EACH_PTR(arg);
1995 }
1996
1997 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1998 {
1999 struct range_list *rl = NULL;
2000 struct smatch_state *state;
2001 struct symbol *type;
2002 char fullname[256];
2003
2004 if (strcmp(key, "*$") == 0)
2005 snprintf(fullname, sizeof(fullname), "*%s", name);
2006 else if (strncmp(key, "$", 1) == 0)
2007 snprintf(fullname, 256, "%s%s", name, key + 1);
2008 else
2009 return;
2010
2011 type = get_member_type_from_key(symbol_expression(sym), key);
2012 str_to_rl(type, value, &rl);
2013 state = alloc_estate_rl(rl);
2014 set_state(SMATCH_EXTRA, fullname, sym, state);
2015 }
2016
2017 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2018 {
2019 struct range_list *rl = NULL;
2020 struct smatch_state *state;
2021 struct symbol *type;
2022 char fullname[256];
2023 sval_t max;
2024
2025 if (strcmp(key, "*$") == 0)
2026 snprintf(fullname, sizeof(fullname), "*%s", name);
2027 else if (strncmp(key, "$", 1) == 0)
2028 snprintf(fullname, 256, "%s%s", name, key + 1);
2029 else
2030 return;
2031
2032 state = get_state(SMATCH_EXTRA, fullname, sym);
2033 if (!state)
2034 return;
2035 type = get_member_type_from_key(symbol_expression(sym), key);
2036 str_to_rl(type, value, &rl);
2037 if (!rl_to_sval(rl, &max))
2038 return;
2039 estate_set_fuzzy_max(state, max);
2040 }
2041
2042 struct smatch_state *get_extra_state(struct expression *expr)
2043 {
2044 char *name;
2045 struct symbol *sym;
2046 struct smatch_state *ret = NULL;
2047 struct range_list *rl;
2048
2049 if (is_pointer(expr) && get_address_rl(expr, &rl))
2050 return alloc_estate_rl(rl);
2051
2052 name = expr_to_known_chunk_sym(expr, &sym);
2053 if (!name)
2054 goto free;
2055
2056 ret = get_state(SMATCH_EXTRA, name, sym);
2057 free:
2058 free_string(name);
2059 return ret;
2060 }
2061
2062 void register_smatch_extra(int id)
2063 {
2064 my_id = id;
2065
2066 add_merge_hook(my_id, &merge_estates);
2067 add_unmatched_state_hook(my_id, &unmatched_state);
2068 select_caller_info_hook(set_param_value, PARAM_VALUE);
2069 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
2070 select_return_states_before(&db_limited_before);
2071 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2072 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2073 select_return_states_hook(PARAM_ADD, &db_param_add);
2074 select_return_states_hook(PARAM_SET, &db_param_set);
2075 select_return_states_hook(PARAM_VALUE, &db_param_value);
2076 select_return_states_after(&db_limited_after);
2077 }
2078
2079 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2080 {
2081 struct var_sym_list *links;
2082 struct var_sym *tmp;
2083 struct smatch_state *state;
2084
2085 links = sm->state->data;
2086
2087 FOR_EACH_PTR(links, tmp) {
2088 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2089 if (!state)
2090 continue;
2091 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2092 } END_FOR_EACH_PTR(tmp);
2093 set_state(link_id, sm->name, sm->sym, &undefined);
2094 }
2095
2096 void register_smatch_extra_links(int id)
2097 {
2098 link_id = id;
2099 }
2100
2101 void register_smatch_extra_late(int id)
2102 {
2103 add_merge_hook(link_id, &merge_link_states);
2104 add_modification_hook(link_id, &match_link_modify);
2105 add_hook(&match_dereferences, DEREF_HOOK);
2106 add_hook(&match_pointer_as_array, OP_HOOK);
2107 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
2108 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2109 add_hook(&match_assign, ASSIGNMENT_HOOK);
2110 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2111 add_hook(&unop_expr, OP_HOOK);
2112 add_hook(&asm_expr, ASM_HOOK);
2113 add_untracked_param_hook(&match_untracked_array);
2114
2115 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
2116 add_member_info_callback(my_id, struct_member_callback);
2117 add_split_return_callback(&returned_struct_members);
2118
2119 add_hook(&assume_indexes_are_valid, OP_HOOK);
2120 }
Static analysis for C