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extra, db: don't use PARAM_VALUE for return states
[smatch.git] / smatch_comparison.c
blob881038026b43b01ab42e91e807059391c14ed39b
1 /*
2 * Copyright (C) 2012 Oracle.
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 * The point here is to store the relationships between two variables.
20 * Ie: y > x.
21 * To do that we create a state with the two variables in alphabetical order:
22 * ->name = "x vs y" and the state would be "<". On the false path the state
23 * would be ">=".
24 *
25 * Part of the trick of it is that if x or y is modified then we need to reset
26 * the state. We need to keep a list of all the states which depend on x and
27 * all the states which depend on y. The link_id code handles this.
28 *
29 */
30
31 #include "smatch.h"
32 #include "smatch_extra.h"
33 #include "smatch_slist.h"
34
35 static int compare_id;
36 static int link_id;
37 static int inc_dec_id;
38 static int inc_dec_link_id;
39
40 /* for handling for loops */
41 STATE(start);
42 STATE(incremented);
43
44 ALLOCATOR(compare_data, "compare data");
45
46 static struct symbol *vsl_to_sym(struct var_sym_list *vsl)
47 {
48 struct var_sym *vs;
49
50 if (!vsl)
51 return NULL;
52 if (ptr_list_size((struct ptr_list *)vsl) != 1)
53 return NULL;
54 vs = first_ptr_list((struct ptr_list *)vsl);
55 return vs->sym;
56 }
57
58 static struct smatch_state *alloc_compare_state(
59 const char *var1, struct var_sym_list *vsl1,
60 int comparison,
61 const char *var2, struct var_sym_list *vsl2)
62 {
63 struct smatch_state *state;
64 struct compare_data *data;
65
66 state = __alloc_smatch_state(0);
67 state->name = alloc_sname(show_special(comparison));
68 data = __alloc_compare_data(0);
69 data->var1 = alloc_sname(var1);
70 data->vsl1 = clone_var_sym_list(vsl1);
71 data->comparison = comparison;
72 data->var2 = alloc_sname(var2);
73 data->vsl2 = clone_var_sym_list(vsl2);
74 state->data = data;
75 return state;
76 }
77
78 static int state_to_comparison(struct smatch_state *state)
79 {
80 if (!state || !state->data)
81 return 0;
82 return ((struct compare_data *)state->data)->comparison;
83 }
84
85 /*
86 * flip_comparison() reverses the op left and right. So "x >= y" becomes "y <= x".
87 */
88 int flip_comparison(int op)
89 {
90 switch (op) {
91 case 0:
92 return 0;
93 case '<':
94 return '>';
95 case SPECIAL_UNSIGNED_LT:
96 return SPECIAL_UNSIGNED_GT;
97 case SPECIAL_LTE:
98 return SPECIAL_GTE;
99 case SPECIAL_UNSIGNED_LTE:
100 return SPECIAL_UNSIGNED_GTE;
101 case SPECIAL_EQUAL:
102 return SPECIAL_EQUAL;
103 case SPECIAL_NOTEQUAL:
104 return SPECIAL_NOTEQUAL;
105 case SPECIAL_GTE:
106 return SPECIAL_LTE;
107 case SPECIAL_UNSIGNED_GTE:
108 return SPECIAL_UNSIGNED_LTE;
109 case '>':
110 return '<';
111 case SPECIAL_UNSIGNED_GT:
112 return SPECIAL_UNSIGNED_LT;
113 default:
114 sm_msg("internal smatch bug. unhandled comparison %d", op);
115 return op;
116 }
117 }
118
119 int negate_comparison(int op)
120 {
121 switch (op) {
122 case 0:
123 return 0;
124 case '<':
125 return SPECIAL_GTE;
126 case SPECIAL_UNSIGNED_LT:
127 return SPECIAL_UNSIGNED_GTE;
128 case SPECIAL_LTE:
129 return '>';
130 case SPECIAL_UNSIGNED_LTE:
131 return SPECIAL_UNSIGNED_GT;
132 case SPECIAL_EQUAL:
133 return SPECIAL_NOTEQUAL;
134 case SPECIAL_NOTEQUAL:
135 return SPECIAL_EQUAL;
136 case SPECIAL_GTE:
137 return '<';
138 case SPECIAL_UNSIGNED_GTE:
139 return SPECIAL_UNSIGNED_LT;
140 case '>':
141 return SPECIAL_LTE;
142 case SPECIAL_UNSIGNED_GT:
143 return SPECIAL_UNSIGNED_LTE;
144 default:
145 sm_msg("internal smatch bug. unhandled comparison %d", op);
146 return op;
147 }
148 }
149
150 static int rl_comparison(struct range_list *left_rl, struct range_list *right_rl)
151 {
152 sval_t left_min, left_max, right_min, right_max;
153
154 if (!left_rl || !right_rl)
155 return 0;
156
157 left_min = rl_min(left_rl);
158 left_max = rl_max(left_rl);
159 right_min = rl_min(right_rl);
160 right_max = rl_max(right_rl);
161
162 if (left_min.value == left_max.value &&
163 right_min.value == right_max.value &&
164 left_min.value == right_min.value)
165 return SPECIAL_EQUAL;
166
167 if (sval_cmp(left_max, right_min) < 0)
168 return '<';
169 if (sval_cmp(left_max, right_min) == 0)
170 return SPECIAL_LTE;
171 if (sval_cmp(left_min, right_max) > 0)
172 return '>';
173 if (sval_cmp(left_min, right_max) == 0)
174 return SPECIAL_GTE;
175
176 return 0;
177 }
178
179 static struct range_list *get_orig_rl(struct var_sym_list *vsl)
180 {
181 struct symbol *sym;
182 struct smatch_state *state;
183
184 if (!vsl)
185 return NULL;
186 sym = vsl_to_sym(vsl);
187 if (!sym || !sym->ident)
188 return NULL;
189 state = get_orig_estate(sym->ident->name, sym);
190 return estate_rl(state);
191 }
192
193 static struct smatch_state *unmatched_comparison(struct sm_state *sm)
194 {
195 struct compare_data *data = sm->state->data;
196 struct range_list *left_rl, *right_rl;
197 int op;
198
199 if (!data)
200 return &undefined;
201
202 if (strstr(data->var1, " orig"))
203 left_rl = get_orig_rl(data->vsl1);
204 else if (!get_implied_rl_var_sym(data->var1, vsl_to_sym(data->vsl1), &left_rl))
205 return &undefined;
206 if (strstr(data->var2, " orig"))
207 right_rl = get_orig_rl(data->vsl2);
208 else if (!get_implied_rl_var_sym(data->var2, vsl_to_sym(data->vsl2), &right_rl))
209 return &undefined;
210
211
212 op = rl_comparison(left_rl, right_rl);
213 if (op)
214 return alloc_compare_state(data->var1, data->vsl1, op, data->var2, data->vsl2);
215
216 return &undefined;
217 }
218
219 /* remove_unsigned_from_comparison() is obviously a hack. */
220 static int remove_unsigned_from_comparison(int op)
221 {
222 switch (op) {
223 case SPECIAL_UNSIGNED_LT:
224 return '<';
225 case SPECIAL_UNSIGNED_LTE:
226 return SPECIAL_LTE;
227 case SPECIAL_UNSIGNED_GTE:
228 return SPECIAL_GTE;
229 case SPECIAL_UNSIGNED_GT:
230 return '>';
231 default:
232 return op;
233 }
234 }
235
236 /*
237 * This is for when you merge states "a < b" and "a == b", the result is that
238 * we can say for sure, "a <= b" after the merge.
239 */
240 static int merge_comparisons(int one, int two)
241 {
242 int LT, EQ, GT;
243
244 one = remove_unsigned_from_comparison(one);
245 two = remove_unsigned_from_comparison(two);
246
247 if (one == two)
248 return one;
249
250 LT = EQ = GT = 0;
251
252 switch (one) {
253 case '<':
254 LT = 1;
255 break;
256 case SPECIAL_LTE:
257 LT = 1;
258 EQ = 1;
259 break;
260 case SPECIAL_EQUAL:
261 EQ = 1;
262 break;
263 case SPECIAL_GTE:
264 GT = 1;
265 EQ = 1;
266 break;
267 case '>':
268 GT = 1;
269 }
270
271 switch (two) {
272 case '<':
273 LT = 1;
274 break;
275 case SPECIAL_LTE:
276 LT = 1;
277 EQ = 1;
278 break;
279 case SPECIAL_EQUAL:
280 EQ = 1;
281 break;
282 case SPECIAL_GTE:
283 GT = 1;
284 EQ = 1;
285 break;
286 case '>':
287 GT = 1;
288 }
289
290 if (LT && EQ && GT)
291 return 0;
292 if (LT && EQ)
293 return SPECIAL_LTE;
294 if (LT && GT)
295 return SPECIAL_NOTEQUAL;
296 if (LT)
297 return '<';
298 if (EQ && GT)
299 return SPECIAL_GTE;
300 if (GT)
301 return '>';
302 return 0;
303 }
304
305 /*
306 * This is for if you have "a < b" and "b <= c". Or in other words,
307 * "a < b <= c". You would call this like get_combined_comparison('<', '<=').
308 * The return comparison would be '<'.
309 *
310 * This function is different from merge_comparisons(), for example:
311 * merge_comparison('<', '==') returns '<='
312 * get_combined_comparison('<', '==') returns '<'
313 */
314 static int combine_comparisons(int left_compare, int right_compare)
315 {
316 int LT, EQ, GT;
317
318 left_compare = remove_unsigned_from_comparison(left_compare);
319 right_compare = remove_unsigned_from_comparison(right_compare);
320
321 LT = EQ = GT = 0;
322
323 switch (left_compare) {
324 case '<':
325 LT++;
326 break;
327 case SPECIAL_LTE:
328 LT++;
329 EQ++;
330 break;
331 case SPECIAL_EQUAL:
332 return right_compare;
333 case SPECIAL_GTE:
334 GT++;
335 EQ++;
336 break;
337 case '>':
338 GT++;
339 }
340
341 switch (right_compare) {
342 case '<':
343 LT++;
344 break;
345 case SPECIAL_LTE:
346 LT++;
347 EQ++;
348 break;
349 case SPECIAL_EQUAL:
350 return left_compare;
351 case SPECIAL_GTE:
352 GT++;
353 EQ++;
354 break;
355 case '>':
356 GT++;
357 }
358
359 if (LT == 2) {
360 if (EQ == 2)
361 return SPECIAL_LTE;
362 return '<';
363 }
364
365 if (GT == 2) {
366 if (EQ == 2)
367 return SPECIAL_GTE;
368 return '>';
369 }
370 return 0;
371 }
372
373 static int filter_comparison(int orig, int op)
374 {
375 if (orig == op)
376 return orig;
377
378 switch (orig) {
379 case 0:
380 return op;
381 case '<':
382 switch (op) {
383 case '<':
384 case SPECIAL_LTE:
385 case SPECIAL_NOTEQUAL:
386 return '<';
387 }
388 return 0;
389 case SPECIAL_LTE:
390 switch (op) {
391 case '<':
392 case SPECIAL_LTE:
393 case SPECIAL_EQUAL:
394 return op;
395 case SPECIAL_NOTEQUAL:
396 return '<';
397 }
398 return 0;
399 case SPECIAL_EQUAL:
400 switch (op) {
401 case SPECIAL_LTE:
402 case SPECIAL_EQUAL:
403 case SPECIAL_GTE:
404 case SPECIAL_UNSIGNED_LTE:
405 case SPECIAL_UNSIGNED_GTE:
406 return SPECIAL_EQUAL;
407 }
408 return 0;
409 case SPECIAL_NOTEQUAL:
410 switch (op) {
411 case '<':
412 case SPECIAL_LTE:
413 return '<';
414 case SPECIAL_UNSIGNED_LT:
415 case SPECIAL_UNSIGNED_LTE:
416 return SPECIAL_UNSIGNED_LT;
417 case SPECIAL_NOTEQUAL:
418 return op;
419 case '>':
420 case SPECIAL_GTE:
421 return '>';
422 case SPECIAL_UNSIGNED_GT:
423 case SPECIAL_UNSIGNED_GTE:
424 return SPECIAL_UNSIGNED_GT;
425 }
426 return 0;
427 case SPECIAL_GTE:
428 switch (op) {
429 case SPECIAL_LTE:
430 return SPECIAL_EQUAL;
431 case '>':
432 case SPECIAL_GTE:
433 case SPECIAL_EQUAL:
434 return op;
435 case SPECIAL_NOTEQUAL:
436 return '>';
437 }
438 return 0;
439 case '>':
440 switch (op) {
441 case '>':
442 case SPECIAL_GTE:
443 case SPECIAL_NOTEQUAL:
444 return '>';
445 }
446 return 0;
447 case SPECIAL_UNSIGNED_LT:
448 switch (op) {
449 case SPECIAL_UNSIGNED_LT:
450 case SPECIAL_UNSIGNED_LTE:
451 case SPECIAL_NOTEQUAL:
452 return SPECIAL_UNSIGNED_LT;
453 }
454 return 0;
455 case SPECIAL_UNSIGNED_LTE:
456 switch (op) {
457 case SPECIAL_UNSIGNED_LT:
458 case SPECIAL_UNSIGNED_LTE:
459 case SPECIAL_EQUAL:
460 return op;
461 case SPECIAL_NOTEQUAL:
462 return SPECIAL_UNSIGNED_LT;
463 case SPECIAL_UNSIGNED_GTE:
464 return SPECIAL_EQUAL;
465 }
466 return 0;
467 case SPECIAL_UNSIGNED_GTE:
468 switch (op) {
469 case SPECIAL_UNSIGNED_LTE:
470 return SPECIAL_EQUAL;
471 case SPECIAL_NOTEQUAL:
472 return SPECIAL_UNSIGNED_GT;
473 case SPECIAL_EQUAL:
474 case SPECIAL_UNSIGNED_GTE:
475 case SPECIAL_UNSIGNED_GT:
476 return op;
477 }
478 return 0;
479 case SPECIAL_UNSIGNED_GT:
480 switch (op) {
481 case SPECIAL_UNSIGNED_GT:
482 case SPECIAL_UNSIGNED_GTE:
483 case SPECIAL_NOTEQUAL:
484 return SPECIAL_UNSIGNED_GT;
485 }
486 return 0;
487 }
488 return 0;
489 }
490
491 static struct smatch_state *merge_compare_states(struct smatch_state *s1, struct smatch_state *s2)
492 {
493 struct compare_data *data = s1->data;
494 int op;
495
496 op = merge_comparisons(state_to_comparison(s1), state_to_comparison(s2));
497 if (op)
498 return alloc_compare_state(data->var1, data->vsl1, op, data->var2, data->vsl2);
499 return &undefined;
500 }
501
502 static struct smatch_state *alloc_link_state(struct string_list *links)
503 {
504 struct smatch_state *state;
505 static char buf[256];
506 char *tmp;
507 int i;
508
509 state = __alloc_smatch_state(0);
510
511 i = 0;
512 FOR_EACH_PTR(links, tmp) {
513 if (!i++) {
514 snprintf(buf, sizeof(buf), "%s", tmp);
515 } else {
516 append(buf, ", ", sizeof(buf));
517 append(buf, tmp, sizeof(buf));
518 }
519 } END_FOR_EACH_PTR(tmp);
520
521 state->name = alloc_sname(buf);
522 state->data = links;
523 return state;
524 }
525
526 static void save_start_states(struct statement *stmt)
527 {
528 struct symbol *param;
529 char orig[64];
530 char state_name[128];
531 struct smatch_state *state;
532 struct string_list *links;
533 char *link;
534
535 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, param) {
536 struct var_sym_list *vsl1 = NULL;
537 struct var_sym_list *vsl2 = NULL;
538
539 if (!param->ident || !param->ident->name)
540 continue;
541 snprintf(orig, sizeof(orig), "%s orig", param->ident->name);
542 snprintf(state_name, sizeof(state_name), "%s vs %s", param->ident->name, orig);
543 add_var_sym(&vsl1, param->ident->name, param);
544 add_var_sym(&vsl2, orig, param);
545 state = alloc_compare_state(param->ident->name, vsl1, SPECIAL_EQUAL, alloc_sname(orig), vsl2);
546 set_state(compare_id, state_name, NULL, state);
547
548 link = alloc_sname(state_name);
549 links = NULL;
550 insert_string(&links, link);
551 state = alloc_link_state(links);
552 set_state(link_id, param->ident->name, param, state);
553 } END_FOR_EACH_PTR(param);
554 }
555
556 static struct smatch_state *merge_links(struct smatch_state *s1, struct smatch_state *s2)
557 {
558 struct smatch_state *ret;
559 struct string_list *links;
560
561 links = combine_string_lists(s1->data, s2->data);
562 ret = alloc_link_state(links);
563 return ret;
564 }
565
566 static void save_link_var_sym(const char *var, struct symbol *sym, const char *link)
567 {
568 struct smatch_state *old_state, *new_state;
569 struct string_list *links;
570 char *new;
571
572 old_state = get_state(link_id, var, sym);
573 if (old_state)
574 links = clone_str_list(old_state->data);
575 else
576 links = NULL;
577
578 new = alloc_sname(link);
579 insert_string(&links, new);
580
581 new_state = alloc_link_state(links);
582 set_state(link_id, var, sym, new_state);
583 }
584
585 static void match_inc(struct sm_state *sm)
586 {
587 struct string_list *links;
588 struct smatch_state *state;
589 char *tmp;
590
591 links = sm->state->data;
592
593 FOR_EACH_PTR(links, tmp) {
594 state = get_state(compare_id, tmp, NULL);
595
596 switch (state_to_comparison(state)) {
597 case SPECIAL_EQUAL:
598 case SPECIAL_GTE:
599 case SPECIAL_UNSIGNED_GTE:
600 case '>':
601 case SPECIAL_UNSIGNED_GT: {
602 struct compare_data *data = state->data;
603 struct smatch_state *new;
604
605 new = alloc_compare_state(data->var1, data->vsl1, '>', data->var2, data->vsl2);
606 set_state(compare_id, tmp, NULL, new);
607 break;
608 }
609 default:
610 set_state(compare_id, tmp, NULL, &undefined);
611 }
612 } END_FOR_EACH_PTR(tmp);
613 }
614
615 static void match_dec(struct sm_state *sm)
616 {
617 struct string_list *links;
618 struct smatch_state *state;
619 char *tmp;
620
621 links = sm->state->data;
622
623 FOR_EACH_PTR(links, tmp) {
624 state = get_state(compare_id, tmp, NULL);
625
626 switch (state_to_comparison(state)) {
627 case SPECIAL_EQUAL:
628 case SPECIAL_LTE:
629 case SPECIAL_UNSIGNED_LTE:
630 case '<':
631 case SPECIAL_UNSIGNED_LT: {
632 struct compare_data *data = state->data;
633 struct smatch_state *new;
634
635 new = alloc_compare_state(data->var1, data->vsl1, '<', data->var2, data->vsl2);
636 set_state(compare_id, tmp, NULL, new);
637 break;
638 }
639 default:
640 set_state(compare_id, tmp, NULL, &undefined);
641 }
642 } END_FOR_EACH_PTR(tmp);
643 }
644
645 static int match_inc_dec(struct sm_state *sm, struct expression *mod_expr)
646 {
647 if (!mod_expr)
648 return 0;
649 if (mod_expr->type != EXPR_PREOP && mod_expr->type != EXPR_POSTOP)
650 return 0;
651
652 if (mod_expr->op == SPECIAL_INCREMENT) {
653 match_inc(sm);
654 return 1;
655 }
656 if (mod_expr->op == SPECIAL_DECREMENT) {
657 match_dec(sm);
658 return 1;
659 }
660 return 0;
661 }
662
663 static void match_modify(struct sm_state *sm, struct expression *mod_expr)
664 {
665 struct string_list *links;
666 char *tmp;
667
668 /*
669 * if (foo > bar) then ++foo is also > bar.
670 */
671 if (match_inc_dec(sm, mod_expr))
672 return;
673
674 links = sm->state->data;
675
676 FOR_EACH_PTR(links, tmp) {
677 set_state(compare_id, tmp, NULL, &undefined);
678 } END_FOR_EACH_PTR(tmp);
679 set_state(link_id, sm->name, sm->sym, &undefined);
680 }
681
682 static char *chunk_to_var_sym(struct expression *expr, struct symbol **sym)
683 {
684 char *name, *left_name, *right_name;
685 struct symbol *tmp;
686 char buf[128];
687
688 expr = strip_expr(expr);
689 if (!expr)
690 return NULL;
691 if (sym)
692 *sym = NULL;
693
694 if (expr->type == EXPR_PREOP &&
695 (expr->op == SPECIAL_INCREMENT ||
696 expr->op == SPECIAL_DECREMENT))
697 expr = strip_expr(expr->unop);
698
699 name = expr_to_var_sym(expr, &tmp);
700 if (name && tmp) {
701 if (sym)
702 *sym = tmp;
703 return name;
704 }
705 if (name)
706 free_string(name);
707
708 if (expr->type != EXPR_BINOP)
709 return NULL;
710 if (expr->op != '-' && expr->op != '+')
711 return NULL;
712
713 left_name = expr_to_var(expr->left);
714 if (!left_name)
715 return NULL;
716 right_name = expr_to_var(expr->right);
717 if (!right_name) {
718 free_string(left_name);
719 return NULL;
720 }
721 snprintf(buf, sizeof(buf), "%s %s %s", left_name, show_special(expr->op), right_name);
722 free_string(left_name);
723 free_string(right_name);
724 return alloc_string(buf);
725 }
726
727 static char *chunk_to_var(struct expression *expr)
728 {
729 return chunk_to_var_sym(expr, NULL);
730 }
731
732 static void save_link(struct expression *expr, char *link)
733 {
734 char *var;
735 struct symbol *sym;
736
737 expr = strip_expr(expr);
738 if (expr->type == EXPR_BINOP) {
739 char *chunk;
740
741 chunk = chunk_to_var(expr);
742 if (!chunk)
743 return;
744
745 save_link(expr->left, link);
746 save_link(expr->right, link);
747 save_link_var_sym(chunk, NULL, link);
748 return;
749 }
750
751 var = expr_to_var_sym(expr, &sym);
752 if (!var || !sym)
753 goto done;
754
755 save_link_var_sym(var, sym, link);
756 done:
757 free_string(var);
758 }
759
760 static int get_orig_comparison(struct stree *pre_stree, const char *left, const char *right)
761 {
762 struct smatch_state *state;
763 struct compare_data *data;
764 int flip = 0;
765 char state_name[256];
766
767 if (strcmp(left, right) > 0) {
768 const char *tmp = right;
769
770 flip = 1;
771 right = left;
772 left = tmp;
773 }
774
775 snprintf(state_name, sizeof(state_name), "%s vs %s", left, right);
776 state = get_state_stree(pre_stree, compare_id, state_name, NULL);
777 if (!state || !state->data)
778 return 0;
779 data = state->data;
780 if (flip)
781 return flip_comparison(data->comparison);
782 return data->comparison;
783
784 }
785
786 /*
787 * The idea here is that we take a comparison "a < b" and then we look at all
788 * the things which "b" is compared against "b < c" and we say that that implies
789 * a relationship "a < c".
790 *
791 * The names here about because the comparisons are organized like this
792 * "a < b < c".
793 *
794 */
795 static void update_tf_links(struct stree *pre_stree,
796 const char *left_var, struct var_sym_list *left_vsl,
797 int left_comparison, int left_false_comparison,
798 const char *mid_var, struct var_sym_list *mid_vsl,
799 struct string_list *links)
800 {
801 struct smatch_state *state;
802 struct smatch_state *true_state, *false_state;
803 struct compare_data *data;
804 const char *right_var;
805 struct var_sym_list *right_vsl;
806 int orig_comparison;
807 int right_comparison;
808 int true_comparison;
809 int false_comparison;
810 char *tmp;
811 char state_name[256];
812 struct var_sym *vs;
813
814 FOR_EACH_PTR(links, tmp) {
815 state = get_state_stree(pre_stree, compare_id, tmp, NULL);
816 if (!state || !state->data)
817 continue;
818 data = state->data;
819 right_comparison = data->comparison;
820 right_var = data->var2;
821 right_vsl = data->vsl2;
822 if (strcmp(mid_var, right_var) == 0) {
823 right_var = data->var1;
824 right_vsl = data->vsl1;
825 right_comparison = flip_comparison(right_comparison);
826 }
827 if (strcmp(left_var, right_var) == 0)
828 continue;
829
830 orig_comparison = get_orig_comparison(pre_stree, left_var, right_var);
831
832 true_comparison = combine_comparisons(left_comparison, right_comparison);
833 false_comparison = combine_comparisons(left_false_comparison, right_comparison);
834
835 true_comparison = filter_comparison(orig_comparison, true_comparison);
836 false_comparison = filter_comparison(orig_comparison, false_comparison);
837
838 if (strcmp(left_var, right_var) > 0) {
839 const char *tmp_var = left_var;
840 struct var_sym_list *tmp_vsl = left_vsl;
841
842 left_var = right_var;
843 left_vsl = right_vsl;
844 right_var = tmp_var;
845 right_vsl = tmp_vsl;
846 true_comparison = flip_comparison(true_comparison);
847 false_comparison = flip_comparison(false_comparison);
848 }
849
850 if (!true_comparison && !false_comparison)
851 continue;
852
853 if (true_comparison)
854 true_state = alloc_compare_state(left_var, left_vsl, true_comparison, right_var, right_vsl);
855 else
856 true_state = NULL;
857 if (false_comparison)
858 false_state = alloc_compare_state(left_var, left_vsl, false_comparison, right_var, right_vsl);
859 else
860 false_state = NULL;
861
862 snprintf(state_name, sizeof(state_name), "%s vs %s", left_var, right_var);
863 set_true_false_states(compare_id, state_name, NULL, true_state, false_state);
864 FOR_EACH_PTR(left_vsl, vs) {
865 save_link_var_sym(vs->var, vs->sym, state_name);
866 } END_FOR_EACH_PTR(vs);
867 FOR_EACH_PTR(right_vsl, vs) {
868 save_link_var_sym(vs->var, vs->sym, state_name);
869 } END_FOR_EACH_PTR(vs);
870 if (!vsl_to_sym(left_vsl))
871 save_link_var_sym(left_var, NULL, state_name);
872 if (!vsl_to_sym(right_vsl))
873 save_link_var_sym(right_var, NULL, state_name);
874 } END_FOR_EACH_PTR(tmp);
875 }
876
877 static void update_tf_data(struct stree *pre_stree,
878 const char *left_name, struct var_sym_list *left_vsl,
879 const char *right_name, struct var_sym_list *right_vsl,
880 int true_comparison, int false_comparison)
881 {
882 struct smatch_state *state;
883
884 state = get_state_stree(pre_stree, link_id, right_name, vsl_to_sym(right_vsl));
885 if (state)
886 update_tf_links(pre_stree, left_name, left_vsl, true_comparison, false_comparison, right_name, right_vsl, state->data);
887
888 state = get_state_stree(pre_stree, link_id, left_name, vsl_to_sym(left_vsl));
889 if (state)
890 update_tf_links(pre_stree, right_name, right_vsl, flip_comparison(true_comparison), flip_comparison(false_comparison), left_name, left_vsl, state->data);
891 }
892
893 static void iter_modify(struct sm_state *sm, struct expression *mod_expr)
894 {
895 if (sm->state != &start ||
896 !mod_expr ||
897 (mod_expr->type != EXPR_PREOP && mod_expr->type != EXPR_POSTOP) ||
898 mod_expr->op != SPECIAL_INCREMENT)
899 set_state(inc_dec_id, sm->name, sm->sym, &undefined);
900 else
901 set_state(inc_dec_id, sm->name, sm->sym, &incremented);
902 }
903
904 static void handle_for_loops(struct expression *expr, char *state_name, struct smatch_state *false_state)
905 {
906 sval_t sval;
907 char *iter_name, *cap_name;
908 struct symbol *iter_sym, *cap_sym;
909 struct compare_data *data;
910
911 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
912 return;
913
914 if (!__cur_stmt || !__prev_stmt)
915 return;
916 if (__cur_stmt->type != STMT_ITERATOR)
917 return;
918 if (__cur_stmt->iterator_pre_condition != expr)
919 return;
920
921 /* literals are handled in smatch_extra.c */
922 if (get_value(expr->right, &sval))
923 return;
924
925 /* First time checking the condition */
926 if (__prev_stmt == __cur_stmt->iterator_pre_statement) {
927 if (!get_implied_value(expr->left, &sval) ||
928 sval.value != 0)
929 return;
930
931 iter_name = expr_to_var_sym(expr->left, &iter_sym);
932 cap_name = expr_to_var_sym(expr->right, &cap_sym);
933 if (!iter_name || !cap_name || !iter_sym || !cap_sym) {
934 free_string(iter_name);
935 free_string(cap_name);
936 return;
937 }
938
939 set_state(inc_dec_id, iter_name, iter_sym, &start);
940 store_link(inc_dec_link_id, cap_name, cap_sym, iter_name, iter_sym);
941
942 free_string(iter_name);
943 free_string(cap_name);
944 return;
945 }
946
947 /* Second time checking the condtion */
948 if (__prev_stmt != __cur_stmt->iterator_post_statement)
949 return;
950
951 if (get_state_expr(inc_dec_id, expr->left) != &incremented)
952 return;
953
954 data = false_state->data;
955 false_state = alloc_compare_state(data->var1, data->vsl1, SPECIAL_EQUAL, data->var2, data->vsl2);
956
957 set_true_false_states(compare_id, state_name, NULL, NULL, false_state);
958 }
959
960 void __comparison_match_condition(struct expression *expr)
961 {
962 char *left = NULL;
963 char *right = NULL;
964 struct symbol *left_sym, *right_sym;
965 struct var_sym_list *left_vsl, *right_vsl;
966 int op, false_op;
967 int orig_comparison;
968 struct smatch_state *true_state, *false_state;
969 char state_name[256];
970 struct stree *pre_stree;
971 sval_t sval;
972
973 if (expr->type != EXPR_COMPARE)
974 return;
975
976 op = expr->op;
977 false_op = negate_comparison(op);
978
979 if (op == SPECIAL_UNSIGNED_LT &&
980 get_implied_value(expr->left, &sval) &&
981 sval.value == 0)
982 false_op = SPECIAL_EQUAL;
983
984 if (op == SPECIAL_UNSIGNED_GT &&
985 get_implied_value(expr->right, &sval) &&
986 sval.value == 0)
987 false_op = SPECIAL_EQUAL;
988
989 left = chunk_to_var_sym(expr->left, &left_sym);
990 if (!left)
991 goto free;
992 left_vsl = expr_to_vsl(expr->left);
993 right = chunk_to_var_sym(expr->right, &right_sym);
994 if (!right)
995 goto free;
996 right_vsl = expr_to_vsl(expr->right);
997
998 if (strcmp(left, right) > 0) {
999 struct symbol *tmp_sym = left_sym;
1000 char *tmp_name = left;
1001 struct var_sym_list *tmp_vsl = left_vsl;
1002
1003 left = right;
1004 left_sym = right_sym;
1005 left_vsl = right_vsl;
1006 right = tmp_name;
1007 right_sym = tmp_sym;
1008 right_vsl = tmp_vsl;
1009 op = flip_comparison(op);
1010 false_op = flip_comparison(false_op);
1011 }
1012
1013 orig_comparison = get_comparison_strings(left, right);
1014 op = filter_comparison(orig_comparison, op);
1015 false_op = filter_comparison(orig_comparison, false_op);
1016
1017 snprintf(state_name, sizeof(state_name), "%s vs %s", left, right);
1018 true_state = alloc_compare_state(left, left_vsl, op, right, right_vsl);
1019 false_state = alloc_compare_state(left, left_vsl, false_op, right, right_vsl);
1020
1021 pre_stree = clone_stree(__get_cur_stree());
1022 update_tf_data(pre_stree, left, left_vsl, right, right_vsl, op, false_op);
1023 free_stree(&pre_stree);
1024
1025 set_true_false_states(compare_id, state_name, NULL, true_state, false_state);
1026 save_link(expr->left, state_name);
1027 save_link(expr->right, state_name);
1028
1029 handle_for_loops(expr, state_name, false_state);
1030 free:
1031 free_string(left);
1032 free_string(right);
1033 }
1034
1035 static void add_comparison_var_sym(const char *left_name,
1036 struct var_sym_list *left_vsl,
1037 int comparison,
1038 const char *right_name, struct var_sym_list *right_vsl)
1039 {
1040 struct smatch_state *state;
1041 struct var_sym *vs;
1042 char state_name[256];
1043
1044 if (strcmp(left_name, right_name) > 0) {
1045 const char *tmp_name = left_name;
1046 struct var_sym_list *tmp_vsl = left_vsl;
1047
1048 left_name = right_name;
1049 left_vsl = right_vsl;
1050 right_name = tmp_name;
1051 right_vsl = tmp_vsl;
1052 comparison = flip_comparison(comparison);
1053 }
1054 snprintf(state_name, sizeof(state_name), "%s vs %s", left_name, right_name);
1055 state = alloc_compare_state(left_name, left_vsl, comparison, right_name, right_vsl);
1056
1057 set_state(compare_id, state_name, NULL, state);
1058
1059 FOR_EACH_PTR(left_vsl, vs) {
1060 save_link_var_sym(vs->var, vs->sym, state_name);
1061 } END_FOR_EACH_PTR(vs);
1062 FOR_EACH_PTR(right_vsl, vs) {
1063 save_link_var_sym(vs->var, vs->sym, state_name);
1064 } END_FOR_EACH_PTR(vs);
1065 }
1066
1067 static void add_comparison(struct expression *left, int comparison, struct expression *right)
1068 {
1069 char *left_name = NULL;
1070 char *right_name = NULL;
1071 struct symbol *left_sym, *right_sym;
1072 struct var_sym_list *left_vsl, *right_vsl;
1073 struct smatch_state *state;
1074 char state_name[256];
1075
1076 left_name = chunk_to_var_sym(left, &left_sym);
1077 if (!left_name)
1078 goto free;
1079 left_vsl = expr_to_vsl(left);
1080 right_name = chunk_to_var_sym(right, &right_sym);
1081 if (!right_name)
1082 goto free;
1083 right_vsl = expr_to_vsl(right);
1084
1085 if (strcmp(left_name, right_name) > 0) {
1086 struct symbol *tmp_sym = left_sym;
1087 char *tmp_name = left_name;
1088 struct var_sym_list *tmp_vsl = left_vsl;
1089
1090 left_name = right_name;
1091 left_sym = right_sym;
1092 left_vsl = right_vsl;
1093 right_name = tmp_name;
1094 right_sym = tmp_sym;
1095 right_vsl = tmp_vsl;
1096 comparison = flip_comparison(comparison);
1097 }
1098 snprintf(state_name, sizeof(state_name), "%s vs %s", left_name, right_name);
1099 state = alloc_compare_state(left_name, left_vsl, comparison, right_name, right_vsl);
1100
1101 set_state(compare_id, state_name, NULL, state);
1102 save_link(left, state_name);
1103 save_link(right, state_name);
1104
1105 free:
1106 free_string(left_name);
1107 free_string(right_name);
1108 }
1109
1110 static void match_assign_add(struct expression *expr)
1111 {
1112 struct expression *right;
1113 struct expression *r_left, *r_right;
1114 sval_t left_tmp, right_tmp;
1115
1116 right = strip_expr(expr->right);
1117 r_left = strip_expr(right->left);
1118 r_right = strip_expr(right->right);
1119
1120 get_absolute_min(r_left, &left_tmp);
1121 get_absolute_min(r_right, &right_tmp);
1122
1123 if (left_tmp.value > 0)
1124 add_comparison(expr->left, '>', r_right);
1125 else if (left_tmp.value == 0)
1126 add_comparison(expr->left, SPECIAL_GTE, r_right);
1127
1128 if (right_tmp.value > 0)
1129 add_comparison(expr->left, '>', r_left);
1130 else if (right_tmp.value == 0)
1131 add_comparison(expr->left, SPECIAL_GTE, r_left);
1132 }
1133
1134 static void match_assign_sub(struct expression *expr)
1135 {
1136 struct expression *right;
1137 struct expression *r_left, *r_right;
1138 int comparison;
1139 sval_t min;
1140
1141 right = strip_expr(expr->right);
1142 r_left = strip_expr(right->left);
1143 r_right = strip_expr(right->right);
1144
1145 if (get_absolute_min(r_right, &min) && sval_is_negative(min))
1146 return;
1147
1148 comparison = get_comparison(r_left, r_right);
1149
1150 switch (comparison) {
1151 case '>':
1152 case SPECIAL_GTE:
1153 if (implied_not_equal(r_right, 0))
1154 add_comparison(expr->left, '>', r_left);
1155 else
1156 add_comparison(expr->left, SPECIAL_GTE, r_left);
1157 return;
1158 }
1159 }
1160
1161 static void match_assign_divide(struct expression *expr)
1162 {
1163 struct expression *right;
1164 struct expression *r_left, *r_right;
1165 sval_t min;
1166
1167 right = strip_expr(expr->right);
1168 r_left = strip_expr(right->left);
1169 r_right = strip_expr(right->right);
1170 if (!get_implied_min(r_right, &min) || min.value <= 1)
1171 return;
1172
1173 add_comparison(expr->left, '<', r_left);
1174 }
1175
1176 static void match_binop_assign(struct expression *expr)
1177 {
1178 struct expression *right;
1179
1180 right = strip_expr(expr->right);
1181 if (right->op == '+')
1182 match_assign_add(expr);
1183 if (right->op == '-')
1184 match_assign_sub(expr);
1185 if (right->op == '/')
1186 match_assign_divide(expr);
1187 }
1188
1189 static void copy_comparisons(struct expression *left, struct expression *right)
1190 {
1191 struct string_list *links;
1192 struct smatch_state *state;
1193 struct compare_data *data;
1194 struct symbol *left_sym, *right_sym;
1195 char *left_var = NULL;
1196 char *right_var = NULL;
1197 struct var_sym_list *left_vsl;
1198 const char *var;
1199 struct var_sym_list *vsl;
1200 int comparison;
1201 char *tmp;
1202
1203 left_var = chunk_to_var_sym(left, &left_sym);
1204 if (!left_var)
1205 goto done;
1206 left_vsl = expr_to_vsl(left);
1207 right_var = chunk_to_var_sym(right, &right_sym);
1208 if (!right_var)
1209 goto done;
1210
1211 state = get_state(link_id, right_var, right_sym);
1212 if (!state)
1213 return;
1214 links = state->data;
1215
1216 FOR_EACH_PTR(links, tmp) {
1217 state = get_state(compare_id, tmp, NULL);
1218 if (!state || !state->data)
1219 continue;
1220 data = state->data;
1221 comparison = data->comparison;
1222 var = data->var2;
1223 vsl = data->vsl2;
1224 if (strcmp(var, right_var) == 0) {
1225 var = data->var1;
1226 vsl = data->vsl1;
1227 comparison = flip_comparison(comparison);
1228 }
1229 add_comparison_var_sym(left_var, left_vsl, comparison, var, vsl);
1230 } END_FOR_EACH_PTR(tmp);
1231
1232 done:
1233 free_string(right_var);
1234 }
1235
1236 static void match_assign(struct expression *expr)
1237 {
1238 struct expression *right;
1239
1240 if (expr->op != '=')
1241 return;
1242 if (__in_fake_assign || outside_of_function())
1243 return;
1244
1245 if (is_struct(expr->left))
1246 return;
1247
1248 copy_comparisons(expr->left, expr->right);
1249 add_comparison(expr->left, SPECIAL_EQUAL, expr->right);
1250
1251 right = strip_expr(expr->right);
1252 if (right->type == EXPR_BINOP)
1253 match_binop_assign(expr);
1254 }
1255
1256 int get_comparison_strings(const char *one, const char *two)
1257 {
1258 char buf[256];
1259 struct smatch_state *state;
1260 int invert = 0;
1261 int ret = 0;
1262
1263 if (strcmp(one, two) == 0)
1264 return SPECIAL_EQUAL;
1265
1266 if (strcmp(one, two) > 0) {
1267 const char *tmp = one;
1268
1269 one = two;
1270 two = tmp;
1271 invert = 1;
1272 }
1273
1274 snprintf(buf, sizeof(buf), "%s vs %s", one, two);
1275 state = get_state(compare_id, buf, NULL);
1276 if (state)
1277 ret = state_to_comparison(state);
1278
1279 if (invert)
1280 ret = flip_comparison(ret);
1281
1282 return ret;
1283 }
1284
1285 int get_comparison(struct expression *a, struct expression *b)
1286 {
1287 char *one = NULL;
1288 char *two = NULL;
1289 int ret = 0;
1290
1291 one = chunk_to_var(a);
1292 if (!one)
1293 goto free;
1294 two = chunk_to_var(b);
1295 if (!two)
1296 goto free;
1297
1298 ret = get_comparison_strings(one, two);
1299 free:
1300 free_string(one);
1301 free_string(two);
1302 return ret;
1303 }
1304
1305 int possible_comparison(struct expression *a, int comparison, struct expression *b)
1306 {
1307 char *one = NULL;
1308 char *two = NULL;
1309 int ret = 0;
1310 char buf[256];
1311 struct sm_state *sm;
1312 int saved;
1313
1314 one = chunk_to_var(a);
1315 if (!one)
1316 goto free;
1317 two = chunk_to_var(b);
1318 if (!two)
1319 goto free;
1320
1321
1322 if (strcmp(one, two) == 0 && comparison == SPECIAL_EQUAL) {
1323 ret = 1;
1324 goto free;
1325 }
1326
1327 if (strcmp(one, two) > 0) {
1328 char *tmp = one;
1329
1330 one = two;
1331 two = tmp;
1332 comparison = flip_comparison(comparison);
1333 }
1334
1335 snprintf(buf, sizeof(buf), "%s vs %s", one, two);
1336 sm = get_sm_state(compare_id, buf, NULL);
1337 if (!sm)
1338 goto free;
1339
1340 FOR_EACH_PTR(sm->possible, sm) {
1341 if (!sm->state->data)
1342 continue;
1343 saved = ((struct compare_data *)sm->state->data)->comparison;
1344 if (saved == comparison)
1345 ret = 1;
1346 if (comparison == SPECIAL_EQUAL &&
1347 (saved == SPECIAL_LTE ||
1348 saved == SPECIAL_GTE ||
1349 saved == SPECIAL_UNSIGNED_LTE ||
1350 saved == SPECIAL_UNSIGNED_GTE))
1351 ret = 1;
1352 if (ret == 1)
1353 goto free;
1354 } END_FOR_EACH_PTR(sm);
1355
1356 return ret;
1357 free:
1358 free_string(one);
1359 free_string(two);
1360 return ret;
1361 }
1362
1363 struct state_list *get_all_comparisons(struct expression *expr)
1364 {
1365 struct smatch_state *state;
1366 struct string_list *links;
1367 struct state_list *ret = NULL;
1368 struct sm_state *sm;
1369 char *tmp;
1370
1371 state = get_state_expr(link_id, expr);
1372 if (!state)
1373 return NULL;
1374 links = state->data;
1375
1376 FOR_EACH_PTR(links, tmp) {
1377 sm = get_sm_state(compare_id, tmp, NULL);
1378 if (!sm)
1379 continue;
1380 // FIXME have to compare name with vsl
1381 add_ptr_list(&ret, sm);
1382 } END_FOR_EACH_PTR(tmp);
1383
1384 return ret;
1385 }
1386
1387 struct state_list *get_all_possible_equal_comparisons(struct expression *expr)
1388 {
1389 struct smatch_state *state;
1390 struct string_list *links;
1391 struct state_list *ret = NULL;
1392 struct sm_state *sm;
1393 char *tmp;
1394
1395 state = get_state_expr(link_id, expr);
1396 if (!state)
1397 return NULL;
1398 links = state->data;
1399
1400 FOR_EACH_PTR(links, tmp) {
1401 sm = get_sm_state(compare_id, tmp, NULL);
1402 if (!sm)
1403 continue;
1404 if (!strchr(sm->state->name, '='))
1405 continue;
1406 if (strcmp(sm->state->name, "!=") == 0)
1407 continue;
1408 add_ptr_list(&ret, sm);
1409 } END_FOR_EACH_PTR(tmp);
1410
1411 return ret;
1412 }
1413
1414 static void update_links_from_call(struct expression *left,
1415 int left_compare,
1416 struct expression *right)
1417 {
1418 struct string_list *links;
1419 struct smatch_state *state;
1420 struct compare_data *data;
1421 struct symbol *left_sym, *right_sym;
1422 char *left_var = NULL;
1423 char *right_var = NULL;
1424 struct var_sym_list *left_vsl;
1425 const char *var;
1426 struct var_sym_list *vsl;
1427 int comparison;
1428 char *tmp;
1429
1430 left_var = chunk_to_var_sym(left, &left_sym);
1431 if (!left_var)
1432 goto done;
1433 left_vsl = expr_to_vsl(left);
1434 right_var = chunk_to_var_sym(right, &right_sym);
1435 if (!right_var)
1436 goto done;
1437
1438 state = get_state(link_id, right_var, right_sym);
1439 if (!state)
1440 return;
1441 links = state->data;
1442
1443 FOR_EACH_PTR(links, tmp) {
1444 state = get_state(compare_id, tmp, NULL);
1445 if (!state || !state->data)
1446 continue;
1447 data = state->data;
1448 comparison = data->comparison;
1449 var = data->var2;
1450 vsl = data->vsl2;
1451 if (strcmp(var, right_var) == 0) {
1452 var = data->var1;
1453 vsl = data->vsl1;
1454 comparison = flip_comparison(comparison);
1455 }
1456 comparison = combine_comparisons(left_compare, comparison);
1457 if (!comparison)
1458 continue;
1459 add_comparison_var_sym(left_var, left_vsl, comparison, var, vsl);
1460 } END_FOR_EACH_PTR(tmp);
1461
1462 done:
1463 free_string(right_var);
1464 }
1465
1466 void __add_comparison_info(struct expression *expr, struct expression *call, const char *range)
1467 {
1468 struct expression *arg;
1469 int comparison;
1470 const char *c = range;
1471
1472 if (!str_to_comparison_arg(c, call, &comparison, &arg))
1473 return;
1474 update_links_from_call(expr, comparison, arg);
1475 add_comparison(expr, comparison, arg);
1476 }
1477
1478 static char *range_comparison_to_param_helper(struct expression *expr, char starts_with, int ignore)
1479 {
1480 struct symbol *param;
1481 char *var = NULL;
1482 char buf[256];
1483 char *ret_str = NULL;
1484 int compare;
1485 int i;
1486
1487 var = chunk_to_var(expr);
1488 if (!var)
1489 goto free;
1490
1491 i = -1;
1492 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, param) {
1493 i++;
1494 if (i == ignore)
1495 continue;
1496 if (!param->ident)
1497 continue;
1498 snprintf(buf, sizeof(buf), "%s orig", param->ident->name);
1499 compare = get_comparison_strings(var, buf);
1500 if (!compare)
1501 continue;
1502 if (show_special(compare)[0] != starts_with)
1503 continue;
1504 snprintf(buf, sizeof(buf), "[%s$%d]", show_special(compare), i);
1505 ret_str = alloc_sname(buf);
1506 break;
1507 } END_FOR_EACH_PTR(param);
1508
1509 free:
1510 free_string(var);
1511 return ret_str;
1512 }
1513
1514 char *expr_equal_to_param(struct expression *expr, int ignore)
1515 {
1516 return range_comparison_to_param_helper(expr, '=', ignore);
1517 }
1518
1519 char *expr_lte_to_param(struct expression *expr, int ignore)
1520 {
1521 return range_comparison_to_param_helper(expr, '<', ignore);
1522 }
1523
1524 char *expr_param_comparison(struct expression *expr, int ignore)
1525 {
1526 struct symbol *param;
1527 char *var = NULL;
1528 char buf[256];
1529 char *ret_str = NULL;
1530 int compare;
1531 int i;
1532
1533 var = chunk_to_var(expr);
1534 if (!var)
1535 goto free;
1536
1537 i = -1;
1538 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, param) {
1539 i++;
1540 if (i == ignore)
1541 continue;
1542 if (!param->ident)
1543 continue;
1544 snprintf(buf, sizeof(buf), "%s orig", param->ident->name);
1545 compare = get_comparison_strings(var, buf);
1546 if (!compare)
1547 continue;
1548 snprintf(buf, sizeof(buf), "[%s$%d]", show_special(compare), i);
1549 ret_str = alloc_sname(buf);
1550 break;
1551 } END_FOR_EACH_PTR(param);
1552
1553 free:
1554 free_string(var);
1555 return ret_str;
1556 }
1557
1558 static void free_data(struct symbol *sym)
1559 {
1560 if (__inline_fn)
1561 return;
1562 clear_compare_data_alloc();
1563 }
1564
1565 void register_comparison(int id)
1566 {
1567 compare_id = id;
1568 add_hook(&match_assign, ASSIGNMENT_HOOK);
1569 add_hook(&save_start_states, AFTER_DEF_HOOK);
1570 add_unmatched_state_hook(compare_id, unmatched_comparison);
1571 add_merge_hook(compare_id, &merge_compare_states);
1572 add_hook(&free_data, AFTER_FUNC_HOOK);
1573 }
1574
1575 void register_comparison_links(int id)
1576 {
1577 link_id = id;
1578 add_merge_hook(link_id, &merge_links);
1579 add_modification_hook(link_id, &match_modify);
1580 }
1581
1582 void register_comparison_inc_dec(int id)
1583 {
1584 inc_dec_id = id;
1585 add_modification_hook(inc_dec_id, &iter_modify);
1586 }
1587
1588 void register_comparison_inc_dec_links(int id)
1589 {
1590 inc_dec_link_id = id;
1591 set_up_link_functions(inc_dec_id, inc_dec_link_id);
1592 }
1593
1594 static void filter_by_sm(struct sm_state *sm, int op,
1595 struct stree_stack **true_stack,
1596 struct stree_stack **false_stack)
1597 {
1598 struct compare_data *data;
1599 int istrue = 0;
1600 int isfalse = 0;
1601
1602 if (!sm)
1603 return;
1604 data = sm->state->data;
1605 if (!data)
1606 return;
1607
1608 if (data->comparison &&
1609 data->comparison == filter_comparison(data->comparison, op))
1610 istrue = 1;
1611
1612 if (data->comparison &&
1613 data->comparison == filter_comparison(data->comparison, negate_comparison(op)))
1614 isfalse = 1;
1615
1616 if (istrue)
1617 add_pool(true_stack, sm->pool);
1618 if (isfalse)
1619 add_pool(false_stack, sm->pool);
1620
1621 if (sm->merged) {
1622 filter_by_sm(sm->left, op, true_stack, false_stack);
1623 filter_by_sm(sm->right, op, true_stack, false_stack);
1624 }
1625 }
1626
1627 struct sm_state *comparison_implication_hook(struct expression *expr,
1628 struct stree_stack **true_stack,
1629 struct stree_stack **false_stack)
1630 {
1631 struct sm_state *sm;
1632 char *left, *right;
1633 int op;
1634 static char buf[256];
1635
1636 if (expr->type != EXPR_COMPARE)
1637 return NULL;
1638
1639 op = expr->op;
1640
1641 left = expr_to_var(expr->left);
1642 right = expr_to_var(expr->right);
1643 if (!left || !right) {
1644 free_string(left);
1645 free_string(right);
1646 return NULL;
1647 }
1648
1649 if (strcmp(left, right) > 0) {
1650 char *tmp = left;
1651
1652 left = right;
1653 right = tmp;
1654 op = flip_comparison(op);
1655 }
1656
1657 snprintf(buf, sizeof(buf), "%s vs %s", left, right);
1658 sm = get_sm_state(compare_id, buf, NULL);
1659 if (!sm)
1660 return NULL;
1661 if (!sm->merged)
1662 return NULL;
1663
1664 filter_by_sm(sm, op, true_stack, false_stack);
1665 if (!*true_stack && !*false_stack)
1666 return NULL;
1667
1668 return sm;
1669 }
Static analysis for C