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db: try to create a link from data to function (through function pointers)
[smatch.git] / smatch_extra.c
blobe6b5f50e7060971182303008313aa129ba03a389
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 #define _GNU_SOURCE
24 #include <string.h>
25
26 #include <stdlib.h>
27 #include <errno.h>
28 #ifndef __USE_ISOC99
29 #define __USE_ISOC99
30 #endif
31 #include <limits.h>
32 #include "parse.h"
33 #include "smatch.h"
34 #include "smatch_slist.h"
35 #include "smatch_extra.h"
36
37 static int my_id;
38 static int link_id;
39
40 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr);
41
42 struct string_list *__ignored_macros = NULL;
43 static int in_warn_on_macro(void)
44 {
45 struct statement *stmt;
46 char *tmp;
47 char *macro;
48
49 stmt = get_current_statement();
50 if (!stmt)
51 return 0;
52 macro = get_macro_name(stmt->pos);
53 if (!macro)
54 return 0;
55
56 FOR_EACH_PTR(__ignored_macros, tmp) {
57 if (!strcmp(tmp, macro))
58 return 1;
59 } END_FOR_EACH_PTR(tmp);
60 return 0;
61 }
62
63 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
64 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
65 static struct void_fn_list *extra_mod_hooks;
66 static struct void_fn_list *extra_nomod_hooks;
67
68 void add_extra_mod_hook(mod_hook *fn)
69 {
70 mod_hook **p = malloc(sizeof(mod_hook *));
71 *p = fn;
72 add_ptr_list(&extra_mod_hooks, p);
73 }
74
75 void add_extra_nomod_hook(mod_hook *fn)
76 {
77 mod_hook **p = malloc(sizeof(mod_hook *));
78 *p = fn;
79 add_ptr_list(&extra_nomod_hooks, p);
80 }
81
82 void call_extra_hooks(struct void_fn_list *hooks, const char *name, struct symbol *sym, struct smatch_state *state)
83 {
84 mod_hook **fn;
85
86 FOR_EACH_PTR(hooks, fn) {
87 (*fn)(name, sym, state);
88 } END_FOR_EACH_PTR(fn);
89 }
90
91 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
92 {
93 call_extra_hooks(extra_mod_hooks, name, sym, state);
94 }
95
96 void call_extra_nomod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
97 {
98 call_extra_hooks(extra_nomod_hooks, name, sym, state);
99 }
100
101 static bool in_param_set;
102 static void set_extra_mod_helper(const char *name, struct symbol *sym, struct smatch_state *state)
103 {
104 remove_from_equiv(name, sym);
105 call_extra_mod_hooks(name, sym, state);
106 if ((__in_fake_assign || in_param_set) &&
107 estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
108 return;
109 set_state(SMATCH_EXTRA, name, sym, state);
110 }
111
112 static void set_extra_nomod_helper(const char *name, struct symbol *sym, struct smatch_state *state)
113 {
114 call_extra_nomod_hooks(name, sym, state);
115 set_state(SMATCH_EXTRA, name, sym, state);
116 }
117
118 static char *get_pointed_at(const char *name, struct symbol *sym, struct symbol **new_sym)
119 {
120 struct expression *assigned;
121
122 if (name[0] != '*')
123 return NULL;
124 if (strcmp(name + 1, sym->ident->name) != 0)
125 return NULL;
126
127 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
128 if (!assigned)
129 return NULL;
130 assigned = strip_parens(assigned);
131 if (assigned->type != EXPR_PREOP || assigned->op != '&')
132 return NULL;
133
134 return expr_to_var_sym(assigned->unop, new_sym);
135 }
136
137 char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
138 {
139 struct expression *assigned;
140 char *orig_name = NULL;
141 char buf[256];
142 char *ret = NULL;
143 int skip;
144
145 *new_sym = NULL;
146
147 if (!sym || !sym->ident)
148 return NULL;
149
150 ret = get_pointed_at(name, sym, new_sym);
151 if (ret)
152 return ret;
153
154 skip = strlen(sym->ident->name);
155 if (name[skip] != '-' || name[skip + 1] != '>')
156 return NULL;
157 skip += 2;
158
159 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
160 if (!assigned)
161 return NULL;
162 if (assigned->type == EXPR_CALL)
163 return map_call_to_other_name_sym(name, sym, new_sym);
164 if (assigned->type == EXPR_PREOP || assigned->op == '&') {
165
166 orig_name = expr_to_var_sym(assigned, new_sym);
167 if (!orig_name || !*new_sym)
168 goto free;
169
170 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + skip);
171 ret = alloc_string(buf);
172 free_string(orig_name);
173 return ret;
174 }
175
176 if (assigned->type != EXPR_DEREF)
177 goto free;
178
179 orig_name = expr_to_var_sym(assigned, new_sym);
180 if (!orig_name || !*new_sym)
181 goto free;
182
183 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + skip);
184 ret = alloc_string(buf);
185 free_string(orig_name);
186 return ret;
187
188 free:
189 free_string(orig_name);
190 return NULL;
191 }
192
193 void set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
194 {
195 char *new_name;
196 struct symbol *new_sym;
197
198 set_extra_mod_helper(name, sym, state);
199 new_name = get_other_name_sym(name, sym, &new_sym);
200 if (new_name && new_sym)
201 set_extra_mod_helper(new_name, new_sym, state);
202 free_string(new_name);
203 }
204
205 static void clear_array_states(struct expression *array)
206 {
207 struct sm_state *sm;
208
209 sm = get_sm_state_expr(link_id, array);
210 if (sm)
211 match_link_modify(sm, NULL);
212 }
213
214 static void set_extra_array_mod(struct expression *expr, struct smatch_state *state)
215 {
216 struct expression *array;
217 struct var_sym_list *vsl;
218 struct var_sym *vs;
219 char *name;
220 struct symbol *sym;
221
222 array = get_array_base(expr);
223
224 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
225 if (!name || !vsl) {
226 clear_array_states(array);
227 goto free;
228 }
229
230 FOR_EACH_PTR(vsl, vs) {
231 store_link(link_id, vs->var, vs->sym, name, sym);
232 } END_FOR_EACH_PTR(vs);
233
234 call_extra_mod_hooks(name, sym, state);
235 set_state(SMATCH_EXTRA, name, sym, state);
236 free:
237 free_string(name);
238 }
239
240 void set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
241 {
242 struct symbol *sym;
243 char *name;
244
245 if (is_array(expr)) {
246 set_extra_array_mod(expr, state);
247 return;
248 }
249
250 expr = strip_expr(expr);
251 name = expr_to_var_sym(expr, &sym);
252 if (!name || !sym)
253 goto free;
254 set_extra_mod(name, sym, state);
255 free:
256 free_string(name);
257 }
258
259 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
260 {
261 char *new_name;
262 struct symbol *new_sym;
263 struct relation *rel;
264 struct smatch_state *orig_state;
265
266 orig_state = get_state(SMATCH_EXTRA, name, sym);
267
268 /* don't save unknown states if leaving it blank is the same */
269 if (!orig_state && estate_is_unknown(state))
270 return;
271
272 new_name = get_other_name_sym(name, sym, &new_sym);
273 if (new_name && new_sym)
274 set_extra_nomod_helper(new_name, new_sym, state);
275 free_string(new_name);
276
277 if (!estate_related(orig_state)) {
278 set_extra_nomod_helper(name, sym, state);
279 return;
280 }
281
282 set_related(state, estate_related(orig_state));
283 FOR_EACH_PTR(estate_related(orig_state), rel) {
284 struct smatch_state *estate;
285
286 if (option_debug_related)
287 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
288 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
289 if (!estate)
290 continue;
291 set_extra_nomod_helper(rel->name, rel->sym, clone_estate_cast(estate_type(estate), state));
292 } END_FOR_EACH_PTR(rel);
293 }
294
295 void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct smatch_state *state)
296 {
297 struct var_sym *vs;
298
299 FOR_EACH_PTR(vsl, vs) {
300 store_link(link_id, vs->var, vs->sym, name, sym);
301 } END_FOR_EACH_PTR(vs);
302
303 set_extra_nomod(name, sym, state);
304 }
305
306 /*
307 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
308 */
309 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
310 {
311 struct var_sym_list *vsl;
312 struct var_sym *vs;
313 char *name;
314 struct symbol *sym;
315
316 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
317 if (!name || !vsl)
318 goto free;
319 FOR_EACH_PTR(vsl, vs) {
320 store_link(link_id, vs->var, vs->sym, name, sym);
321 } END_FOR_EACH_PTR(vs);
322
323 set_extra_nomod(name, sym, state);
324 free:
325 free_string(name);
326 }
327
328 static void set_extra_true_false(const char *name, struct symbol *sym,
329 struct smatch_state *true_state,
330 struct smatch_state *false_state)
331 {
332 char *new_name;
333 struct symbol *new_sym;
334 struct relation *rel;
335 struct smatch_state *orig_state;
336
337 if (!true_state && !false_state)
338 return;
339
340 if (in_warn_on_macro())
341 return;
342
343 new_name = get_other_name_sym(name, sym, &new_sym);
344 if (new_name && new_sym)
345 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
346 free_string(new_name);
347
348 orig_state = get_state(SMATCH_EXTRA, name, sym);
349
350 if (!estate_related(orig_state)) {
351 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
352 return;
353 }
354
355 if (true_state)
356 set_related(true_state, estate_related(orig_state));
357 if (false_state)
358 set_related(false_state, estate_related(orig_state));
359
360 FOR_EACH_PTR(estate_related(orig_state), rel) {
361 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
362 true_state, false_state);
363 } END_FOR_EACH_PTR(rel);
364 }
365
366 static void set_extra_chunk_true_false(struct expression *expr,
367 struct smatch_state *true_state,
368 struct smatch_state *false_state)
369 {
370 struct var_sym_list *vsl;
371 struct var_sym *vs;
372 struct symbol *type;
373 char *name;
374 struct symbol *sym;
375
376 if (in_warn_on_macro())
377 return;
378
379 type = get_type(expr);
380 if (!type)
381 return;
382
383 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
384 if (!name || !vsl)
385 goto free;
386 FOR_EACH_PTR(vsl, vs) {
387 store_link(link_id, vs->var, vs->sym, name, sym);
388 } END_FOR_EACH_PTR(vs);
389
390 set_true_false_states(SMATCH_EXTRA, name, sym,
391 clone_estate(true_state),
392 clone_estate(false_state));
393 free:
394 free_string(name);
395 }
396
397 static void set_extra_expr_true_false(struct expression *expr,
398 struct smatch_state *true_state,
399 struct smatch_state *false_state)
400 {
401 char *name;
402 struct symbol *sym;
403 sval_t sval;
404
405 if (!true_state && !false_state)
406 return;
407
408 if (get_value(expr, &sval))
409 return;
410
411 expr = strip_expr(expr);
412 name = expr_to_var_sym(expr, &sym);
413 if (!name || !sym) {
414 free_string(name);
415 set_extra_chunk_true_false(expr, true_state, false_state);
416 return;
417 }
418 set_extra_true_false(name, sym, true_state, false_state);
419 free_string(name);
420 }
421
422 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
423 {
424 struct expression *iter_var;
425 struct expression *condition;
426 struct sm_state *sm;
427 struct smatch_state *estate;
428 sval_t start;
429
430 condition = strip_expr(loop->iterator_pre_condition);
431 if (!condition)
432 return NULL;
433 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
434 return NULL;
435 if (condition->op != SPECIAL_DECREMENT)
436 return NULL;
437
438 iter_var = condition->unop;
439 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
440 if (!sm)
441 return NULL;
442 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
443 return NULL;
444 start = estate_max(sm->state);
445 if (sval_cmp_val(start, 0) <= 0)
446 return NULL;
447 if (!sval_is_max(start))
448 start.value--;
449
450 if (condition->type == EXPR_PREOP) {
451 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
452 if (estate_has_hard_max(sm->state))
453 estate_set_hard_max(estate);
454 estate_copy_fuzzy_max(estate, sm->state);
455 set_extra_expr_mod(iter_var, estate);
456 }
457 if (condition->type == EXPR_POSTOP) {
458 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
459 if (estate_has_hard_max(sm->state))
460 estate_set_hard_max(estate);
461 estate_copy_fuzzy_max(estate, sm->state);
462 set_extra_expr_mod(iter_var, estate);
463 }
464 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
465 }
466
467 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
468 struct expression *condition)
469 {
470 struct expression *iter_var;
471 struct sm_state *sm;
472 struct smatch_state *estate;
473 sval_t start, end, max;
474
475 iter_var = iter_expr->unop;
476 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
477 if (!sm)
478 return NULL;
479 if (!estate_get_single_value(sm->state, &start))
480 return NULL;
481 if (get_implied_max(condition->right, &end))
482 end = sval_cast(get_type(iter_var), end);
483 else
484 end = sval_type_max(get_type(iter_var));
485
486 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
487 return NULL;
488
489 switch (condition->op) {
490 case SPECIAL_UNSIGNED_LT:
491 case SPECIAL_NOTEQUAL:
492 case '<':
493 if (!sval_is_min(end))
494 end.value--;
495 break;
496 case SPECIAL_UNSIGNED_LTE:
497 case SPECIAL_LTE:
498 break;
499 default:
500 return NULL;
501 }
502 if (sval_cmp(end, start) < 0)
503 return NULL;
504 estate = alloc_estate_range(start, end);
505 if (get_hard_max(condition->right, &max)) {
506 estate_set_hard_max(estate);
507 if (condition->op == '<' ||
508 condition->op == SPECIAL_UNSIGNED_LT ||
509 condition->op == SPECIAL_NOTEQUAL)
510 max.value--;
511 estate_set_fuzzy_max(estate, max);
512 }
513 set_extra_expr_mod(iter_var, estate);
514 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
515 }
516
517 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
518 struct expression *condition)
519 {
520 struct expression *iter_var;
521 struct sm_state *sm;
522 struct smatch_state *estate;
523 sval_t start, end;
524
525 iter_var = iter_expr->unop;
526 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
527 if (!sm)
528 return NULL;
529 if (!estate_get_single_value(sm->state, &start))
530 return NULL;
531 if (!get_implied_min(condition->right, &end))
532 end = sval_type_min(get_type(iter_var));
533 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
534 return NULL;
535
536 switch (condition->op) {
537 case SPECIAL_NOTEQUAL:
538 case '>':
539 if (!sval_is_min(end) && !sval_is_max(end))
540 end.value++;
541 break;
542 case SPECIAL_GTE:
543 break;
544 default:
545 return NULL;
546 }
547 if (sval_cmp(end, start) > 0)
548 return NULL;
549 estate = alloc_estate_range(end, start);
550 estate_set_hard_max(estate);
551 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
552 set_extra_expr_mod(iter_var, estate);
553 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
554 }
555
556 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
557 {
558 struct expression *iter_expr;
559 struct expression *condition;
560
561 if (!loop->iterator_post_statement)
562 return NULL;
563 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
564 return NULL;
565 iter_expr = loop->iterator_post_statement->expression;
566 if (!loop->iterator_pre_condition)
567 return NULL;
568 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
569 return NULL;
570 condition = loop->iterator_pre_condition;
571
572 if (iter_expr->op == SPECIAL_INCREMENT)
573 return handle_canonical_for_inc(iter_expr, condition);
574 if (iter_expr->op == SPECIAL_DECREMENT)
575 return handle_canonical_for_dec(iter_expr, condition);
576 return NULL;
577 }
578
579 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
580 {
581 struct sm_state *ret;
582
583 __push_fake_cur_stree();
584 if (!loop->iterator_post_statement)
585 ret = handle_canonical_while_count_down(loop);
586 else
587 ret = handle_canonical_for_loops(loop);
588 *stree = __pop_fake_cur_stree();
589 return ret;
590 }
591
592 int __iterator_unchanged(struct sm_state *sm)
593 {
594 if (!sm)
595 return 0;
596 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
597 return 1;
598 return 0;
599 }
600
601 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
602 {
603 sval_t after_value;
604
605 /* paranoid checking. prolly not needed */
606 condition = strip_expr(condition);
607 if (!condition)
608 return;
609 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
610 return;
611 if (condition->op != SPECIAL_DECREMENT)
612 return;
613 after_value = estate_min(sm->state);
614 after_value.value--;
615 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
616 }
617
618 void __extra_pre_loop_hook_after(struct sm_state *sm,
619 struct statement *iterator,
620 struct expression *condition)
621 {
622 struct expression *iter_expr;
623 sval_t limit;
624 struct smatch_state *state;
625
626 if (!iterator) {
627 while_count_down_after(sm, condition);
628 return;
629 }
630
631 iter_expr = iterator->expression;
632
633 if (condition->type != EXPR_COMPARE)
634 return;
635 if (iter_expr->op == SPECIAL_INCREMENT) {
636 limit = sval_binop(estate_max(sm->state), '+',
637 sval_type_val(estate_type(sm->state), 1));
638 } else {
639 limit = sval_binop(estate_min(sm->state), '-',
640 sval_type_val(estate_type(sm->state), 1));
641 }
642 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
643 if (iter_expr->op == SPECIAL_INCREMENT)
644 state = alloc_estate_range(estate_min(sm->state), limit);
645 else
646 state = alloc_estate_range(limit, estate_max(sm->state));
647 } else {
648 state = alloc_estate_sval(limit);
649 }
650 if (!estate_has_hard_max(sm->state)) {
651 estate_clear_hard_max(state);
652 }
653 if (estate_has_fuzzy_max(sm->state)) {
654 sval_t hmax = estate_get_fuzzy_max(sm->state);
655 sval_t max = estate_max(sm->state);
656
657 if (sval_cmp(hmax, max) != 0)
658 estate_clear_fuzzy_max(state);
659 } else if (!estate_has_fuzzy_max(sm->state)) {
660 estate_clear_fuzzy_max(state);
661 }
662
663 set_extra_mod(sm->name, sm->sym, state);
664 }
665
666 static struct stree *unmatched_stree;
667 static struct smatch_state *unmatched_state(struct sm_state *sm)
668 {
669 struct smatch_state *state;
670
671 if (unmatched_stree) {
672 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
673 if (state)
674 return state;
675 }
676 if (parent_is_gone_var_sym(sm->name, sm->sym))
677 return alloc_estate_empty();
678 return alloc_estate_whole(estate_type(sm->state));
679 }
680
681 static void clear_the_pointed_at(struct expression *expr)
682 {
683 struct stree *stree;
684 char *name;
685 struct symbol *sym;
686 struct sm_state *tmp;
687
688 name = expr_to_var_sym(expr, &sym);
689 if (!name || !sym)
690 goto free;
691
692 stree = __get_cur_stree();
693 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
694 if (tmp->name[0] != '*')
695 continue;
696 if (tmp->sym != sym)
697 continue;
698 if (strcmp(tmp->name + 1, name) != 0)
699 continue;
700 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
701 } END_FOR_EACH_SM(tmp);
702
703 free:
704 free_string(name);
705 }
706
707 static void match_function_call(struct expression *expr)
708 {
709 struct expression *arg;
710 struct expression *tmp;
711
712 /* if we have the db this is handled in smatch_function_hooks.c */
713 if (!option_no_db)
714 return;
715 if (inlinable(expr->fn))
716 return;
717
718 FOR_EACH_PTR(expr->args, arg) {
719 tmp = strip_expr(arg);
720 if (tmp->type == EXPR_PREOP && tmp->op == '&')
721 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
722 else
723 clear_the_pointed_at(tmp);
724 } END_FOR_EACH_PTR(arg);
725 }
726
727 static int values_fit_type(struct expression *left, struct expression *right)
728 {
729 struct range_list *rl;
730 struct symbol *type;
731
732 type = get_type(left);
733 if (!type)
734 return 0;
735 get_absolute_rl(right, &rl);
736 if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
737 return 0;
738 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
739 return 0;
740 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
741 return 0;
742 return 1;
743 }
744
745 static void save_chunk_info(struct expression *left, struct expression *right)
746 {
747 struct var_sym_list *vsl;
748 struct var_sym *vs;
749 struct expression *add_expr;
750 struct symbol *type;
751 sval_t sval;
752 char *name;
753 struct symbol *sym;
754
755 if (right->type != EXPR_BINOP || right->op != '-')
756 return;
757 if (!get_value(right->left, &sval))
758 return;
759 if (!expr_to_sym(right->right))
760 return;
761
762 add_expr = binop_expression(left, '+', right->right);
763 type = get_type(add_expr);
764 if (!type)
765 return;
766 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
767 if (!name || !vsl)
768 goto free;
769 FOR_EACH_PTR(vsl, vs) {
770 store_link(link_id, vs->var, vs->sym, name, sym);
771 } END_FOR_EACH_PTR(vs);
772
773 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
774 free:
775 free_string(name);
776 }
777
778 static void do_array_assign(struct expression *left, int op, struct expression *right)
779 {
780 struct range_list *rl;
781
782 if (op == '=') {
783 get_absolute_rl(right, &rl);
784 rl = cast_rl(get_type(left), rl);
785 } else {
786 rl = alloc_whole_rl(get_type(left));
787 }
788
789 set_extra_array_mod(left, alloc_estate_rl(rl));
790 }
791
792 static void match_untracked_array(struct expression *call, int param)
793 {
794 struct expression *arg;
795
796 arg = get_argument_from_call_expr(call->args, param);
797 arg = strip_expr(arg);
798
799 clear_array_states(arg);
800 }
801
802 static void match_vanilla_assign(struct expression *left, struct expression *right)
803 {
804 struct range_list *orig_rl = NULL;
805 struct range_list *rl = NULL;
806 struct symbol *right_sym;
807 struct symbol *left_type;
808 struct symbol *right_type;
809 char *right_name = NULL;
810 struct symbol *sym;
811 char *name;
812 sval_t max;
813 struct smatch_state *state;
814 int comparison;
815
816 if (is_struct(left))
817 return;
818
819 save_chunk_info(left, right);
820
821 name = expr_to_var_sym(left, &sym);
822 if (!name) {
823 if (is_array(left))
824 do_array_assign(left, '=', right);
825 return;
826 }
827
828 left_type = get_type(left);
829 right_type = get_type(right);
830
831 right_name = expr_to_var_sym(right, &right_sym);
832
833 if (!__in_fake_assign &&
834 !(right->type == EXPR_PREOP && right->op == '&') &&
835 right_name && right_sym &&
836 values_fit_type(left, right) &&
837 !has_symbol(right, sym)) {
838 set_equiv(left, right);
839 goto free;
840 }
841
842 if (is_pointer(right) && get_address_rl(right, &rl)) {
843 state = alloc_estate_rl(rl);
844 goto done;
845 }
846
847 if (__in_fake_assign) {
848 struct smatch_state *right_state;
849 sval_t sval;
850
851 if (get_value(right, &sval)) {
852 sval = sval_cast(left_type, sval);
853 state = alloc_estate_sval(sval);
854 goto done;
855 }
856
857 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
858 if (right_state) {
859 /* simple assignment */
860 state = clone_estate(right_state);
861 goto done;
862 }
863
864 state = alloc_estate_rl(alloc_whole_rl(left_type));
865 goto done;
866 }
867
868 comparison = get_comparison(left, right);
869 if (comparison) {
870 comparison = flip_comparison(comparison);
871 get_implied_rl(left, &orig_rl);
872 }
873
874 if (get_implied_rl(right, &rl)) {
875 rl = cast_rl(left_type, rl);
876 if (orig_rl)
877 filter_by_comparison(&rl, comparison, orig_rl);
878 state = alloc_estate_rl(rl);
879 if (get_hard_max(right, &max)) {
880 estate_set_hard_max(state);
881 estate_set_fuzzy_max(state, max);
882 }
883 } else {
884 rl = alloc_whole_rl(right_type);
885 rl = cast_rl(left_type, rl);
886 if (orig_rl)
887 filter_by_comparison(&rl, comparison, orig_rl);
888 state = alloc_estate_rl(rl);
889 }
890
891 done:
892 set_extra_mod(name, sym, state);
893 free:
894 free_string(right_name);
895 }
896
897 static int op_remove_assign(int op)
898 {
899 switch (op) {
900 case SPECIAL_ADD_ASSIGN:
901 return '+';
902 case SPECIAL_SUB_ASSIGN:
903 return '-';
904 case SPECIAL_MUL_ASSIGN:
905 return '*';
906 case SPECIAL_DIV_ASSIGN:
907 return '/';
908 case SPECIAL_MOD_ASSIGN:
909 return '%';
910 case SPECIAL_AND_ASSIGN:
911 return '&';
912 case SPECIAL_OR_ASSIGN:
913 return '|';
914 case SPECIAL_XOR_ASSIGN:
915 return '^';
916 case SPECIAL_SHL_ASSIGN:
917 return SPECIAL_LEFTSHIFT;
918 case SPECIAL_SHR_ASSIGN:
919 return SPECIAL_RIGHTSHIFT;
920 default:
921 return op;
922 }
923 }
924
925 static void match_assign(struct expression *expr)
926 {
927 struct range_list *rl = NULL;
928 struct expression *left;
929 struct expression *right;
930 struct expression *binop_expr;
931 struct symbol *left_type;
932 struct symbol *sym;
933 char *name;
934 sval_t left_min, left_max;
935 sval_t right_min, right_max;
936 sval_t res_min, res_max;
937
938 left = strip_expr(expr->left);
939
940 right = strip_parens(expr->right);
941 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
942 right = get_argument_from_call_expr(right->args, 0);
943 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
944 right = strip_parens(right->left);
945
946 if (expr->op == '=' && is_condition(expr->right))
947 return; /* handled in smatch_condition.c */
948 if (expr->op == '=' && right->type == EXPR_CALL)
949 return; /* handled in smatch_function_hooks.c */
950 if (expr->op == '=') {
951 match_vanilla_assign(left, right);
952 return;
953 }
954
955 name = expr_to_var_sym(left, &sym);
956 if (!name)
957 return;
958
959 left_type = get_type(left);
960
961 res_min = sval_type_min(left_type);
962 res_max = sval_type_max(left_type);
963
964 switch (expr->op) {
965 case SPECIAL_ADD_ASSIGN:
966 get_absolute_max(left, &left_max);
967 get_absolute_max(right, &right_max);
968 if (sval_binop_overflows(left_max, '+', sval_cast(left_type, right_max)))
969 break;
970 if (get_implied_min(left, &left_min) &&
971 !sval_is_negative_min(left_min) &&
972 get_implied_min(right, &right_min) &&
973 !sval_is_negative_min(right_min)) {
974 res_min = sval_binop(left_min, '+', right_min);
975 res_min = sval_cast(left_type, res_min);
976 }
977 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
978 break;
979 res_max = sval_binop(left_max, '+', right_max);
980 res_max = sval_cast(left_type, res_max);
981 break;
982 case SPECIAL_SUB_ASSIGN:
983 if (get_implied_max(left, &left_max) &&
984 !sval_is_max(left_max) &&
985 get_implied_min(right, &right_min) &&
986 !sval_is_min(right_min)) {
987 res_max = sval_binop(left_max, '-', right_min);
988 res_max = sval_cast(left_type, res_max);
989 }
990 if (inside_loop())
991 break;
992 if (get_implied_min(left, &left_min) &&
993 !sval_is_min(left_min) &&
994 get_implied_max(right, &right_max) &&
995 !sval_is_max(right_max)) {
996 res_min = sval_binop(left_min, '-', right_max);
997 res_min = sval_cast(left_type, res_min);
998 }
999 break;
1000 case SPECIAL_AND_ASSIGN:
1001 case SPECIAL_MOD_ASSIGN:
1002 case SPECIAL_SHL_ASSIGN:
1003 case SPECIAL_SHR_ASSIGN:
1004 case SPECIAL_OR_ASSIGN:
1005 case SPECIAL_XOR_ASSIGN:
1006 case SPECIAL_MUL_ASSIGN:
1007 case SPECIAL_DIV_ASSIGN:
1008 binop_expr = binop_expression(expr->left,
1009 op_remove_assign(expr->op),
1010 expr->right);
1011 if (get_absolute_rl(binop_expr, &rl)) {
1012 rl = cast_rl(left_type, rl);
1013 set_extra_mod(name, sym, alloc_estate_rl(rl));
1014 goto free;
1015 }
1016 break;
1017 }
1018 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
1019 set_extra_mod(name, sym, alloc_estate_rl(rl));
1020 free:
1021 free_string(name);
1022 }
1023
1024 static struct smatch_state *increment_state(struct smatch_state *state)
1025 {
1026 sval_t min = estate_min(state);
1027 sval_t max = estate_max(state);
1028
1029 if (!estate_rl(state))
1030 return NULL;
1031
1032 if (inside_loop())
1033 max = sval_type_max(max.type);
1034
1035 if (!sval_is_min(min) && !sval_is_max(min))
1036 min.value++;
1037 if (!sval_is_min(max) && !sval_is_max(max))
1038 max.value++;
1039 return alloc_estate_range(min, max);
1040 }
1041
1042 static struct smatch_state *decrement_state(struct smatch_state *state)
1043 {
1044 sval_t min = estate_min(state);
1045 sval_t max = estate_max(state);
1046
1047 if (!estate_rl(state))
1048 return NULL;
1049
1050 if (inside_loop())
1051 min = sval_type_min(min.type);
1052
1053 if (!sval_is_min(min) && !sval_is_max(min))
1054 min.value--;
1055 if (!sval_is_min(max) && !sval_is_max(max))
1056 max.value--;
1057 return alloc_estate_range(min, max);
1058 }
1059
1060 static void clear_pointed_at_state(struct expression *expr)
1061 {
1062 struct symbol *type;
1063
1064 /*
1065 * ALERT: This is sort of a mess. If it's is a struct assigment like
1066 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1067 * the same thing for p++ where "p" is a struct. Most modifications
1068 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1069 * use smatch_modification.c because we have to get the ordering right
1070 * or something. So if you have p++ where p is a pointer to a standard
1071 * c type then we handle that here. What a mess.
1072 */
1073
1074 type = get_type(expr);
1075 if (!type || type->type != SYM_PTR)
1076 return;
1077 type = get_real_base_type(type);
1078 if (!type || type->type != SYM_BASETYPE)
1079 return;
1080 set_extra_expr_mod(deref_expression(expr), alloc_estate_whole(type));
1081 }
1082
1083 static void unop_expr(struct expression *expr)
1084 {
1085 struct smatch_state *state;
1086
1087 if (expr->smatch_flags & Handled)
1088 return;
1089
1090 switch (expr->op) {
1091 case SPECIAL_INCREMENT:
1092 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1093 state = increment_state(state);
1094 if (!state)
1095 state = alloc_estate_whole(get_type(expr));
1096 set_extra_expr_mod(expr->unop, state);
1097 clear_pointed_at_state(expr->unop);
1098 break;
1099 case SPECIAL_DECREMENT:
1100 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1101 state = decrement_state(state);
1102 if (!state)
1103 state = alloc_estate_whole(get_type(expr));
1104 set_extra_expr_mod(expr->unop, state);
1105 clear_pointed_at_state(expr->unop);
1106 break;
1107 default:
1108 return;
1109 }
1110 }
1111
1112 static void asm_expr(struct statement *stmt)
1113 {
1114
1115 struct expression *expr;
1116 struct symbol *type;
1117 int state = 0;
1118
1119 FOR_EACH_PTR(stmt->asm_outputs, expr) {
1120 switch (state) {
1121 case 0: /* identifier */
1122 case 1: /* constraint */
1123 state++;
1124 continue;
1125 case 2: /* expression */
1126 state = 0;
1127 type = get_type(strip_expr(expr));
1128 set_extra_expr_mod(expr, alloc_estate_whole(type));
1129 continue;
1130 }
1131 } END_FOR_EACH_PTR(expr);
1132 }
1133
1134 static void check_dereference(struct expression *expr)
1135 {
1136 struct smatch_state *state;
1137
1138 if (__in_fake_assign)
1139 return;
1140 if (outside_of_function())
1141 return;
1142 state = get_extra_state(expr);
1143 if (state) {
1144 static struct range_list *valid_rl;
1145 struct range_list *rl;
1146
1147 if (!valid_rl) {
1148 valid_rl = alloc_rl(valid_ptr_min_sval, valid_ptr_max_sval);
1149 valid_rl = clone_rl_permanent(valid_rl);
1150 }
1151
1152 rl = rl_intersection(estate_rl(state), valid_rl);
1153 if (rl_equiv(rl, estate_rl(state)))
1154 return;
1155 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1156 } else {
1157 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1158 }
1159 }
1160
1161 static void match_dereferences(struct expression *expr)
1162 {
1163 if (expr->type != EXPR_PREOP)
1164 return;
1165 /* it's saying that foo[1] = bar dereferences foo[1] */
1166 if (is_array(expr))
1167 return;
1168 check_dereference(expr->unop);
1169 }
1170
1171 static void match_pointer_as_array(struct expression *expr)
1172 {
1173 if (!is_array(expr))
1174 return;
1175 check_dereference(get_array_base(expr));
1176 }
1177
1178 static void find_dereferences(struct expression *expr)
1179 {
1180 while (expr->type == EXPR_PREOP) {
1181 if (expr->op == '*')
1182 check_dereference(expr->unop);
1183 expr = strip_expr(expr->unop);
1184 }
1185 }
1186
1187 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
1188 {
1189 struct symbol *sym;
1190 char *name;
1191
1192 name = get_variable_from_key(arg, key, &sym);
1193 if (name && sym)
1194 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1195 free_string(name);
1196
1197 find_dereferences(arg);
1198 }
1199
1200 static sval_t add_one(sval_t sval)
1201 {
1202 sval.value++;
1203 return sval;
1204 }
1205
1206 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1207 {
1208 struct statement *stmt;
1209 struct expression *cond;
1210 struct smatch_state *true_state, *false_state;
1211 sval_t start;
1212 sval_t limit;
1213
1214 /*
1215 * If we're decrementing here then that's a canonical while count down
1216 * so it's handled already. We're only handling loops like:
1217 * i = 0;
1218 * do { ... } while (i++ < 3);
1219 */
1220
1221 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1222 return 0;
1223
1224 stmt = __cur_stmt->parent;
1225 if (!stmt)
1226 return 0;
1227 if (stmt->type == STMT_COMPOUND)
1228 stmt = stmt->parent;
1229 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1230 return 0;
1231
1232 cond = strip_expr(stmt->iterator_post_condition);
1233 if (cond->type != EXPR_COMPARE || cond->op != op)
1234 return 0;
1235 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1236 return 0;
1237
1238 if (!get_implied_value(left->unop, &start))
1239 return 0;
1240 if (!get_implied_value(right, &limit))
1241 return 0;
1242
1243 if (sval_cmp(start, limit) > 0)
1244 return 0;
1245
1246 switch (op) {
1247 case '<':
1248 case SPECIAL_UNSIGNED_LT:
1249 break;
1250 case SPECIAL_LTE:
1251 case SPECIAL_UNSIGNED_LTE:
1252 limit = add_one(limit);
1253 default:
1254 return 0;
1255
1256 }
1257
1258 true_state = alloc_estate_range(add_one(start), limit);
1259 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1260
1261 /* Currently we just discard the false state but when two passes is
1262 * implimented correctly then it will use it.
1263 */
1264
1265 set_extra_expr_true_false(left->unop, true_state, false_state);
1266
1267 return 1;
1268 }
1269
1270 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1271 {
1272 struct range_list *left_orig;
1273 struct range_list *left_true;
1274 struct range_list *left_false;
1275 struct range_list *right_orig;
1276 struct range_list *right_true;
1277 struct range_list *right_false;
1278 struct smatch_state *left_true_state;
1279 struct smatch_state *left_false_state;
1280 struct smatch_state *right_true_state;
1281 struct smatch_state *right_false_state;
1282 sval_t dummy, hard_max;
1283 int left_postop = 0;
1284 int right_postop = 0;
1285
1286 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1287 if (left->type == EXPR_POSTOP) {
1288 left->smatch_flags |= Handled;
1289 left_postop = left->op;
1290 if (handle_postop_inc(left, op, right))
1291 return;
1292 }
1293 left = strip_parens(left->unop);
1294 }
1295 while (left->type == EXPR_ASSIGNMENT)
1296 left = strip_parens(left->left);
1297
1298 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1299 if (right->type == EXPR_POSTOP) {
1300 right->smatch_flags |= Handled;
1301 right_postop = right->op;
1302 }
1303 right = strip_parens(right->unop);
1304 }
1305
1306 get_real_absolute_rl(left, &left_orig);
1307 left_orig = cast_rl(type, left_orig);
1308
1309 get_real_absolute_rl(right, &right_orig);
1310 right_orig = cast_rl(type, right_orig);
1311
1312 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1313
1314 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1315 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1316 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1317 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1318
1319 if (!left_true || !left_false) {
1320 struct range_list *tmp_true, *tmp_false;
1321
1322 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1323 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1324 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1325 if (tmp_true && tmp_false)
1326 __save_imaginary_state(left, tmp_true, tmp_false);
1327 }
1328
1329 if (!right_true || !right_false) {
1330 struct range_list *tmp_true, *tmp_false;
1331
1332 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1333 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1334 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1335 if (tmp_true && tmp_false)
1336 __save_imaginary_state(right, tmp_true, tmp_false);
1337 }
1338
1339 left_true_state = alloc_estate_rl(left_true);
1340 left_false_state = alloc_estate_rl(left_false);
1341 right_true_state = alloc_estate_rl(right_true);
1342 right_false_state = alloc_estate_rl(right_false);
1343
1344 switch (op) {
1345 case '<':
1346 case SPECIAL_UNSIGNED_LT:
1347 case SPECIAL_UNSIGNED_LTE:
1348 case SPECIAL_LTE:
1349 if (get_hard_max(right, &dummy))
1350 estate_set_hard_max(left_true_state);
1351 if (get_hard_max(left, &dummy))
1352 estate_set_hard_max(right_false_state);
1353 break;
1354 case '>':
1355 case SPECIAL_UNSIGNED_GT:
1356 case SPECIAL_UNSIGNED_GTE:
1357 case SPECIAL_GTE:
1358 if (get_hard_max(left, &dummy))
1359 estate_set_hard_max(right_true_state);
1360 if (get_hard_max(right, &dummy))
1361 estate_set_hard_max(left_false_state);
1362 break;
1363 }
1364
1365 switch (op) {
1366 case '<':
1367 case SPECIAL_UNSIGNED_LT:
1368 case SPECIAL_UNSIGNED_LTE:
1369 case SPECIAL_LTE:
1370 if (get_hard_max(right, &hard_max)) {
1371 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1372 hard_max.value--;
1373 estate_set_fuzzy_max(left_true_state, hard_max);
1374 }
1375 if (get_implied_value(right, &hard_max)) {
1376 if (op == SPECIAL_UNSIGNED_LTE ||
1377 op == SPECIAL_LTE)
1378 hard_max.value++;
1379 estate_set_fuzzy_max(left_false_state, hard_max);
1380 }
1381 if (get_hard_max(left, &hard_max)) {
1382 if (op == SPECIAL_UNSIGNED_LTE ||
1383 op == SPECIAL_LTE)
1384 hard_max.value--;
1385 estate_set_fuzzy_max(right_false_state, hard_max);
1386 }
1387 if (get_implied_value(left, &hard_max)) {
1388 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1389 hard_max.value++;
1390 estate_set_fuzzy_max(right_true_state, hard_max);
1391 }
1392 break;
1393 case '>':
1394 case SPECIAL_UNSIGNED_GT:
1395 case SPECIAL_UNSIGNED_GTE:
1396 case SPECIAL_GTE:
1397 if (get_hard_max(left, &hard_max)) {
1398 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1399 hard_max.value--;
1400 estate_set_fuzzy_max(right_true_state, hard_max);
1401 }
1402 if (get_implied_value(left, &hard_max)) {
1403 if (op == SPECIAL_UNSIGNED_GTE ||
1404 op == SPECIAL_GTE)
1405 hard_max.value++;
1406 estate_set_fuzzy_max(right_false_state, hard_max);
1407 }
1408 if (get_hard_max(right, &hard_max)) {
1409 if (op == SPECIAL_UNSIGNED_LTE ||
1410 op == SPECIAL_LTE)
1411 hard_max.value--;
1412 estate_set_fuzzy_max(left_false_state, hard_max);
1413 }
1414 if (get_implied_value(right, &hard_max)) {
1415 if (op == '>' ||
1416 op == SPECIAL_UNSIGNED_GT)
1417 hard_max.value++;
1418 estate_set_fuzzy_max(left_true_state, hard_max);
1419 }
1420 break;
1421 case SPECIAL_EQUAL:
1422 if (get_hard_max(left, &hard_max))
1423 estate_set_fuzzy_max(right_true_state, hard_max);
1424 if (get_hard_max(right, &hard_max))
1425 estate_set_fuzzy_max(left_true_state, hard_max);
1426 break;
1427 }
1428
1429 if (get_hard_max(left, &hard_max)) {
1430 estate_set_hard_max(left_true_state);
1431 estate_set_hard_max(left_false_state);
1432 }
1433 if (get_hard_max(right, &hard_max)) {
1434 estate_set_hard_max(right_true_state);
1435 estate_set_hard_max(right_false_state);
1436 }
1437
1438 if (left_postop == SPECIAL_INCREMENT) {
1439 left_true_state = increment_state(left_true_state);
1440 left_false_state = increment_state(left_false_state);
1441 }
1442 if (left_postop == SPECIAL_DECREMENT) {
1443 left_true_state = decrement_state(left_true_state);
1444 left_false_state = decrement_state(left_false_state);
1445 }
1446 if (right_postop == SPECIAL_INCREMENT) {
1447 right_true_state = increment_state(right_true_state);
1448 right_false_state = increment_state(right_false_state);
1449 }
1450 if (right_postop == SPECIAL_DECREMENT) {
1451 right_true_state = decrement_state(right_true_state);
1452 right_false_state = decrement_state(right_false_state);
1453 }
1454
1455 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1456 left_true_state = NULL;
1457 left_false_state = NULL;
1458 }
1459
1460 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1461 right_true_state = NULL;
1462 right_false_state = NULL;
1463 }
1464
1465 set_extra_expr_true_false(left, left_true_state, left_false_state);
1466 set_extra_expr_true_false(right, right_true_state, right_false_state);
1467 }
1468
1469 static int is_simple_math(struct expression *expr)
1470 {
1471 if (!expr)
1472 return 0;
1473 if (expr->type != EXPR_BINOP)
1474 return 0;
1475 switch (expr->op) {
1476 case '+':
1477 case '-':
1478 case '*':
1479 return 1;
1480 }
1481 return 0;
1482 }
1483
1484 static void move_known_values(struct expression **left_p, struct expression **right_p)
1485 {
1486 struct expression *left = *left_p;
1487 struct expression *right = *right_p;
1488 sval_t sval, dummy;
1489
1490 if (get_implied_value(left, &sval)) {
1491 if (!is_simple_math(right))
1492 return;
1493 if (get_implied_value(right, &dummy))
1494 return;
1495 if (right->op == '*') {
1496 sval_t divisor;
1497
1498 if (!get_value(right->right, &divisor))
1499 return;
1500 if (divisor.value == 0 && sval.value % divisor.value)
1501 return;
1502 *left_p = binop_expression(left, invert_op(right->op), right->right);
1503 *right_p = right->left;
1504 return;
1505 }
1506 if (right->op == '+' && get_value(right->left, &sval)) {
1507 *left_p = binop_expression(left, invert_op(right->op), right->left);
1508 *right_p = right->right;
1509 return;
1510 }
1511 if (get_value(right->right, &sval)) {
1512 *left_p = binop_expression(left, invert_op(right->op), right->right);
1513 *right_p = right->left;
1514 return;
1515 }
1516 return;
1517 }
1518 if (get_implied_value(right, &sval)) {
1519 if (!is_simple_math(left))
1520 return;
1521 if (get_implied_value(left, &dummy))
1522 return;
1523 if (left->op == '*') {
1524 sval_t divisor;
1525
1526 if (!get_value(left->right, &divisor))
1527 return;
1528 if (divisor.value == 0 && sval.value % divisor.value)
1529 return;
1530 *right_p = binop_expression(right, invert_op(left->op), left->right);
1531 *left_p = left->left;
1532 return;
1533 }
1534 if (left->op == '+' && get_value(left->left, &sval)) {
1535 *right_p = binop_expression(right, invert_op(left->op), left->left);
1536 *left_p = left->right;
1537 return;
1538 }
1539
1540 if (get_value(left->right, &sval)) {
1541 *right_p = binop_expression(right, invert_op(left->op), left->right);
1542 *left_p = left->left;
1543 return;
1544 }
1545 return;
1546 }
1547 }
1548
1549 /*
1550 * The reason for do_simple_algebra() is to solve things like:
1551 * if (foo > 66 || foo + bar > 64) {
1552 * "foo" is not really a known variable so it won't be handled by
1553 * move_known_variables() but it's a super common idiom.
1554 *
1555 */
1556 static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
1557 {
1558 struct expression *left = *left_p;
1559 struct expression *right = *right_p;
1560 struct range_list *rl;
1561 sval_t tmp;
1562
1563 if (left->type != EXPR_BINOP || left->op != '+')
1564 return 0;
1565 if (can_integer_overflow(get_type(left), left))
1566 return 0;
1567 if (!get_implied_value(right, &tmp))
1568 return 0;
1569
1570 if (!get_implied_value(left->left, &tmp) &&
1571 get_implied_rl(left->left, &rl) &&
1572 !is_whole_rl(rl)) {
1573 *right_p = binop_expression(right, '-', left->left);
1574 *left_p = left->right;
1575 return 1;
1576 }
1577 if (!get_implied_value(left->right, &tmp) &&
1578 get_implied_rl(left->right, &rl) &&
1579 !is_whole_rl(rl)) {
1580 *right_p = binop_expression(right, '-', left->right);
1581 *left_p = left->left;
1582 return 1;
1583 }
1584
1585 return 0;
1586 }
1587
1588 static int match_func_comparison(struct expression *expr)
1589 {
1590 struct expression *left = strip_expr(expr->left);
1591 struct expression *right = strip_expr(expr->right);
1592 sval_t sval;
1593
1594 /*
1595 * fixme: think about this harder. We should always be trying to limit
1596 * the non-call side as well. If we can't determine the limitter does
1597 * that mean we aren't querying the database and are missing important
1598 * information?
1599 */
1600
1601 if (left->type == EXPR_CALL) {
1602 if (get_implied_value(left, &sval)) {
1603 handle_comparison(get_type(expr), left, expr->op, right);
1604 return 1;
1605 }
1606 function_comparison(left, expr->op, right);
1607 return 1;
1608 }
1609
1610 if (right->type == EXPR_CALL) {
1611 if (get_implied_value(right, &sval)) {
1612 handle_comparison(get_type(expr), left, expr->op, right);
1613 return 1;
1614 }
1615 function_comparison(left, expr->op, right);
1616 return 1;
1617 }
1618
1619 return 0;
1620 }
1621
1622 /* Handle conditions like "if (foo + bar < foo) {" */
1623 static int handle_integer_overflow_test(struct expression *expr)
1624 {
1625 struct expression *left, *right;
1626 struct symbol *type;
1627 sval_t left_min, right_min, min, max;
1628
1629 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
1630 return 0;
1631
1632 left = strip_parens(expr->left);
1633 right = strip_parens(expr->right);
1634
1635 if (left->op != '+')
1636 return 0;
1637
1638 type = get_type(expr);
1639 if (!type)
1640 return 0;
1641 if (type_positive_bits(type) == 32) {
1642 max.type = &uint_ctype;
1643 max.uvalue = (unsigned int)-1;
1644 } else if (type_positive_bits(type) == 64) {
1645 max.type = &ulong_ctype;
1646 max.value = (unsigned long long)-1;
1647 } else {
1648 return 0;
1649 }
1650
1651 if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
1652 return 0;
1653
1654 get_absolute_min(left->left, &left_min);
1655 get_absolute_min(left->right, &right_min);
1656 min = sval_binop(left_min, '+', right_min);
1657
1658 set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
1659 return 1;
1660 }
1661
1662 static void match_comparison(struct expression *expr)
1663 {
1664 struct expression *left_orig = strip_parens(expr->left);
1665 struct expression *right_orig = strip_parens(expr->right);
1666 struct expression *left, *right;
1667 struct expression *prev;
1668 struct symbol *type;
1669
1670 if (match_func_comparison(expr))
1671 return;
1672
1673 type = get_type(expr);
1674 if (!type)
1675 type = &llong_ctype;
1676
1677 if (handle_integer_overflow_test(expr))
1678 return;
1679
1680 left = left_orig;
1681 right = right_orig;
1682 move_known_values(&left, &right);
1683 handle_comparison(type, left, expr->op, right);
1684
1685 left = left_orig;
1686 right = right_orig;
1687 if (do_simple_algebra(&left, &right))
1688 handle_comparison(type, left, expr->op, right);
1689
1690 prev = get_assigned_expr(left_orig);
1691 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1692 left = prev;
1693 right = right_orig;
1694 move_known_values(&left, &right);
1695 handle_comparison(type, left, expr->op, right);
1696 }
1697
1698 prev = get_assigned_expr(right_orig);
1699 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1700 left = left_orig;
1701 right = prev;
1702 move_known_values(&left, &right);
1703 handle_comparison(type, left, expr->op, right);
1704 }
1705 }
1706
1707 static sval_t get_high_mask(sval_t known)
1708 {
1709 sval_t ret;
1710 int i;
1711
1712 ret = known;
1713 ret.value = 0;
1714
1715 for (i = type_bits(known.type) - 1; i >= 0; i--) {
1716 if (known.uvalue & (1ULL << i))
1717 ret.uvalue |= (1ULL << i);
1718 else
1719 return ret;
1720
1721 }
1722 return ret;
1723 }
1724
1725 static void handle_AND_condition(struct expression *expr)
1726 {
1727 struct range_list *orig_rl;
1728 struct range_list *true_rl = NULL;
1729 struct range_list *false_rl = NULL;
1730 sval_t known;
1731 int bit;
1732
1733 if (get_implied_value(expr->left, &known)) {
1734 sval_t low_mask = known;
1735 sval_t high_mask;
1736
1737 if (known.value > 0) {
1738 bit = ffsll(known.value) - 1;
1739 low_mask.uvalue = (1ULL << bit) - 1;
1740 get_absolute_rl(expr->right, &orig_rl);
1741 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
1742 }
1743 high_mask = get_high_mask(known);
1744 if (high_mask.value) {
1745 bit = ffsll(high_mask.value) - 1;
1746 low_mask.uvalue = (1ULL << bit) - 1;
1747
1748 get_absolute_rl(expr->left, &orig_rl);
1749 if (sval_is_negative(rl_min(orig_rl)))
1750 orig_rl = remove_range(orig_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
1751 false_rl = remove_range(orig_rl, low_mask, sval_type_max(known.type));
1752 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
1753 false_rl = remove_range(false_rl,
1754 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
1755 sval_type_val(rl_type(false_rl), -1));
1756 }
1757 }
1758 set_extra_expr_true_false(expr->right,
1759 true_rl ? alloc_estate_rl(true_rl) : NULL,
1760 false_rl ? alloc_estate_rl(false_rl) : NULL);
1761
1762 return;
1763 }
1764
1765 if (get_implied_value(expr->right, &known)) {
1766 sval_t low_mask = known;
1767 sval_t high_mask;
1768
1769 if (known.value > 0) {
1770 bit = ffsll(known.value) - 1;
1771 low_mask.uvalue = (1ULL << bit) - 1;
1772 get_absolute_rl(expr->left, &orig_rl);
1773 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
1774 }
1775 high_mask = get_high_mask(known);
1776 if (high_mask.value) {
1777 bit = ffsll(high_mask.value) - 1;
1778 low_mask.uvalue = (1ULL << bit) - 1;
1779
1780 get_absolute_rl(expr->left, &orig_rl);
1781 if (sval_is_negative(rl_min(orig_rl)))
1782 orig_rl = remove_range(orig_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
1783 false_rl = remove_range(orig_rl, low_mask, sval_type_max(known.type));
1784 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
1785 false_rl = remove_range(false_rl,
1786 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
1787 sval_type_val(rl_type(false_rl), -1));
1788 }
1789 }
1790 set_extra_expr_true_false(expr->left,
1791 true_rl ? alloc_estate_rl(true_rl) : NULL,
1792 false_rl ? alloc_estate_rl(false_rl) : NULL);
1793 return;
1794 }
1795 }
1796
1797 static void handle_MOD_condition(struct expression *expr)
1798 {
1799 struct range_list *orig_rl;
1800 struct range_list *true_rl;
1801 struct range_list *false_rl = NULL;
1802 sval_t right;
1803 sval_t zero = {
1804 .value = 0,
1805 };
1806
1807 if (!get_implied_value(expr->right, &right) || right.value == 0)
1808 return;
1809 get_absolute_rl(expr->left, &orig_rl);
1810
1811 zero.type = rl_type(orig_rl);
1812
1813 /* We're basically dorking around the min and max here */
1814 true_rl = remove_range(orig_rl, zero, zero);
1815 if (!sval_is_max(rl_max(true_rl)) &&
1816 !(rl_max(true_rl).value % right.value))
1817 true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));
1818
1819 if (rl_equiv(true_rl, orig_rl))
1820 true_rl = NULL;
1821
1822 if (sval_is_positive(rl_min(orig_rl)) &&
1823 (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
1824 sval_t add;
1825 int i;
1826
1827 add = rl_min(orig_rl);
1828 add.value += right.value - (add.value % right.value);
1829 add.value -= right.value;
1830
1831 for (i = 0; i < 5; i++) {
1832 add.value += right.value;
1833 if (add.value > rl_max(orig_rl).value)
1834 break;
1835 add_range(&false_rl, add, add);
1836 }
1837 } else {
1838 if (rl_min(orig_rl).uvalue != 0 &&
1839 rl_min(orig_rl).uvalue < right.uvalue) {
1840 sval_t chop = right;
1841 chop.value--;
1842 false_rl = remove_range(orig_rl, zero, chop);
1843 }
1844
1845 if (!sval_is_max(rl_max(orig_rl)) &&
1846 (rl_max(orig_rl).value % right.value)) {
1847 sval_t chop = rl_max(orig_rl);
1848 chop.value -= chop.value % right.value;
1849 chop.value++;
1850 if (!false_rl)
1851 false_rl = clone_rl(orig_rl);
1852 false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
1853 }
1854 }
1855
1856 set_extra_expr_true_false(expr->left,
1857 true_rl ? alloc_estate_rl(true_rl) : NULL,
1858 false_rl ? alloc_estate_rl(false_rl) : NULL);
1859 }
1860
1861 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1862 void __extra_match_condition(struct expression *expr)
1863 {
1864 struct smatch_state *pre_state;
1865 struct smatch_state *true_state;
1866 struct smatch_state *false_state;
1867 struct range_list *pre_rl;
1868
1869 expr = strip_expr(expr);
1870 switch (expr->type) {
1871 case EXPR_CALL:
1872 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1873 return;
1874 case EXPR_PREOP:
1875 case EXPR_SYMBOL:
1876 case EXPR_DEREF: {
1877 sval_t zero;
1878
1879 zero = sval_blank(expr);
1880 zero.value = 0;
1881
1882 pre_state = get_extra_state(expr);
1883 if (estate_is_empty(pre_state))
1884 return;
1885 if (pre_state)
1886 pre_rl = estate_rl(pre_state);
1887 else
1888 get_absolute_rl(expr, &pre_rl);
1889 if (possibly_true_rl(pre_rl, SPECIAL_EQUAL, rl_zero()))
1890 false_state = alloc_estate_sval(zero);
1891 else
1892 false_state = alloc_estate_empty();
1893 true_state = alloc_estate_rl(remove_range(pre_rl, zero, zero));
1894 set_extra_expr_true_false(expr, true_state, false_state);
1895 return;
1896 }
1897 case EXPR_COMPARE:
1898 match_comparison(expr);
1899 return;
1900 case EXPR_ASSIGNMENT:
1901 __extra_match_condition(expr->left);
1902 return;
1903 case EXPR_BINOP:
1904 if (expr->op == '&')
1905 handle_AND_condition(expr);
1906 if (expr->op == '%')
1907 handle_MOD_condition(expr);
1908 return;
1909 }
1910 }
1911
1912 static void assume_indexes_are_valid(struct expression *expr)
1913 {
1914 struct expression *array_expr;
1915 int array_size;
1916 struct expression *offset;
1917 struct symbol *offset_type;
1918 struct range_list *rl_before;
1919 struct range_list *rl_after;
1920 struct range_list *filter = NULL;
1921 sval_t size;
1922
1923 expr = strip_expr(expr);
1924 if (!is_array(expr))
1925 return;
1926
1927 offset = get_array_offset(expr);
1928 offset_type = get_type(offset);
1929 if (offset_type && type_signed(offset_type)) {
1930 filter = alloc_rl(sval_type_min(offset_type),
1931 sval_type_val(offset_type, -1));
1932 }
1933
1934 array_expr = get_array_base(expr);
1935 array_size = get_real_array_size(array_expr);
1936 if (array_size > 1) {
1937 size = sval_type_val(offset_type, array_size);
1938 add_range(&filter, size, sval_type_max(offset_type));
1939 }
1940
1941 if (!filter)
1942 return;
1943 get_absolute_rl(offset, &rl_before);
1944 rl_after = rl_filter(rl_before, filter);
1945 if (rl_equiv(rl_before, rl_after))
1946 return;
1947 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1948 }
1949
1950 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1951 int implied_not_equal(struct expression *expr, long long val)
1952 {
1953 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1954 }
1955
1956 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1957 {
1958 struct smatch_state *estate;
1959
1960 estate = get_state(SMATCH_EXTRA, name, sym);
1961 if (!estate)
1962 return 0;
1963 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1964 return 1;
1965 return 0;
1966 }
1967
1968 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1969 {
1970 char buf[256];
1971 char *start;
1972 char *end;
1973 struct smatch_state *state;
1974
1975 strncpy(buf, name, sizeof(buf) - 1);
1976 buf[sizeof(buf) - 1] = '\0';
1977
1978 start = &buf[0];
1979 while (*start == '*') {
1980 start++;
1981 state = get_state(SMATCH_EXTRA, start, sym);
1982 if (!state)
1983 continue;
1984 if (!estate_rl(state))
1985 return 1;
1986 if (estate_min(state).value == 0 &&
1987 estate_max(state).value == 0)
1988 return 1;
1989 }
1990
1991 start = &buf[0];
1992 while (*start == '&')
1993 start++;
1994
1995 while ((end = strrchr(start, '-'))) {
1996 *end = '\0';
1997 state = get_state(SMATCH_EXTRA, start, sym);
1998 if (!state)
1999 continue;
2000 if (estate_min(state).value == 0 &&
2001 estate_max(state).value == 0)
2002 return 1;
2003 }
2004 return 0;
2005 }
2006
2007 int parent_is_null(struct expression *expr)
2008 {
2009 struct symbol *sym;
2010 char *var;
2011 int ret = 0;
2012
2013 expr = strip_expr(expr);
2014 var = expr_to_var_sym(expr, &sym);
2015 if (!var || !sym)
2016 goto free;
2017 ret = parent_is_null_var_sym(var, sym);
2018 free:
2019 free_string(var);
2020 return ret;
2021 }
2022
2023 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
2024 {
2025 *(int *)found = 1;
2026 return 0;
2027 }
2028
2029 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2030 {
2031 sval_t sval;
2032 int found = 0;
2033
2034 /* for function pointers assume everything is used */
2035 if (call->fn->type != EXPR_SYMBOL)
2036 return 0;
2037
2038 /*
2039 * kzalloc() information is treated as special because so there is just
2040 * a lot of stuff initialized to zero and it makes building the database
2041 * take hours and hours.
2042 *
2043 * In theory, we should just remove this line and not pass any unused
2044 * information, but I'm not sure enough that this code works so I want
2045 * to hold off on that for now.
2046 */
2047 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
2048 return 0;
2049
2050 run_sql(&param_used_callback, &found,
2051 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
2052 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
2053 if (found)
2054 return 0;
2055
2056 /* If the database is not built yet, then assume everything is used */
2057 run_sql(&param_used_callback, &found,
2058 "select * from call_implies where %s and type = %d;",
2059 get_static_filter(call->fn->symbol), PARAM_USED);
2060 if (!found)
2061 return 0;
2062
2063 return 1;
2064 }
2065
2066 struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
2067 {
2068 struct smatch_state *state;
2069
2070 /*
2071 * Here is the difference between implied value and real absolute, say
2072 * you have:
2073 *
2074 * int a = (u8)x;
2075 *
2076 * Then you know that a is 0-255. That's real absolute. But you don't
2077 * know for sure that it actually goes up to 255. So it's not implied.
2078 * Implied indicates a degree of certainty.
2079 *
2080 * But then say you cap "a" at 8. That means you know it goes up to
2081 * 8. So now the implied value is s32min-8. But you can combine it
2082 * with the real absolute to say that actually it's 0-8.
2083 *
2084 * We are combining it here. But now that I think about it, this is
2085 * probably not the ideal place to combine it because it should proably
2086 * be done earlier. Oh well, this is an improvement on what was there
2087 * before so I'm going to commit this code.
2088 *
2089 */
2090
2091 state = get_real_absolute_state_var_sym(name, sym);
2092 if (!state || !estate_rl(state))
2093 return start;
2094
2095 return rl_intersection(estate_rl(state), start);
2096 }
2097
2098 struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
2099 {
2100 struct smatch_state *state;
2101
2102 state = get_real_absolute_state(expr);
2103 if (!state || !estate_rl(state))
2104 return start;
2105
2106 return rl_intersection(estate_rl(state), start);
2107 }
2108
2109 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2110 {
2111 struct range_list *rl;
2112
2113 if (estate_is_whole(sm->state))
2114 return;
2115 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
2116 return;
2117 rl = estate_rl(sm->state);
2118 rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
2119 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
2120 if (estate_has_fuzzy_max(sm->state))
2121 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
2122 sval_to_str(estate_get_fuzzy_max(sm->state)));
2123 }
2124
2125 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
2126 {
2127 struct symbol *returned_sym;
2128 struct sm_state *sm;
2129 const char *param_name;
2130 char *compare_str;
2131 char buf[256];
2132
2133 returned_sym = expr_to_sym(expr);
2134 if (!returned_sym)
2135 return;
2136
2137 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
2138 if (!estate_rl(sm->state))
2139 continue;
2140 if (returned_sym != sm->sym)
2141 continue;
2142
2143 param_name = get_param_name(sm);
2144 if (!param_name)
2145 continue;
2146 if (strcmp(param_name, "$") == 0)
2147 continue;
2148 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
2149 if (!compare_str && estate_is_whole(sm->state))
2150 continue;
2151 snprintf(buf, sizeof(buf), "%s%s", sm->state->name, compare_str ?: "");
2152
2153 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
2154 -1, param_name, buf);
2155 } END_FOR_EACH_SM(sm);
2156 }
2157
2158 static void db_limited_before(void)
2159 {
2160 unmatched_stree = clone_stree(__get_cur_stree());
2161 }
2162
2163 static void db_limited_after(void)
2164 {
2165 free_stree(&unmatched_stree);
2166 }
2167
2168 static int rl_fits_in_type(struct range_list *rl, struct symbol *type)
2169 {
2170 if (type_bits(rl_type(rl)) <= type_bits(type))
2171 return 1;
2172 if (sval_cmp(rl_max(rl), sval_type_max(type)) > 0)
2173 return 0;
2174 if (sval_is_negative(rl_min(rl)) &&
2175 sval_cmp(rl_min(rl), sval_type_min(type)) < 0)
2176 return 0;
2177 return 1;
2178 }
2179
2180 static int basically_the_same(struct range_list *orig, struct range_list *new)
2181 {
2182 if (rl_equiv(orig, new))
2183 return 1;
2184
2185 /*
2186 * The whole range is essentially the same as 0,4096-27777777777 so
2187 * don't overwrite the implications just to store that.
2188 *
2189 */
2190 if (rl_type(orig)->type == SYM_PTR &&
2191 is_whole_rl(orig) &&
2192 rl_min(new).value == 0 &&
2193 rl_max(new).value == valid_ptr_max)
2194 return 1;
2195 return 0;
2196 }
2197
2198 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
2199 {
2200 struct expression *arg;
2201 char *name;
2202 struct symbol *sym;
2203 struct var_sym_list *vsl = NULL;
2204 struct sm_state *sm;
2205 struct symbol *compare_type, *var_type;
2206 struct range_list *rl;
2207 struct range_list *limit;
2208 struct range_list *new;
2209
2210 while (expr->type == EXPR_ASSIGNMENT)
2211 expr = strip_expr(expr->right);
2212 if (expr->type != EXPR_CALL)
2213 return;
2214
2215 arg = get_argument_from_call_expr(expr->args, param);
2216 if (!arg)
2217 return;
2218
2219 name = get_chunk_from_key(arg, key, &sym, &vsl);
2220 if (!name)
2221 return;
2222 if (op != PARAM_LIMIT && !sym)
2223 goto free;
2224
2225 if (strcmp(key, "$") == 0)
2226 compare_type = get_arg_type(expr->fn, param);
2227 else
2228 compare_type = get_member_type_from_key(arg, key);
2229
2230 sm = get_sm_state(SMATCH_EXTRA, name, sym);
2231 if (sm)
2232 rl = estate_rl(sm->state);
2233 else
2234 rl = alloc_whole_rl(compare_type);
2235
2236 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
2237 goto free;
2238
2239 call_results_to_rl(expr, compare_type, value, &limit);
2240 new = rl_intersection(rl, limit);
2241
2242 var_type = get_member_type_from_key(arg, key);
2243 new = cast_rl(var_type, new);
2244
2245 /* We want to preserve the implications here */
2246 if (sm && basically_the_same(estate_rl(sm->state), new))
2247 __set_sm(sm); /* FIXME: Is this really necessary? */
2248 else {
2249 char *tmp_name;
2250 struct symbol *tmp_sym;
2251
2252 tmp_name = map_long_to_short_name_sym(name, sym, &tmp_sym);
2253 if (tmp_name && tmp_sym) {
2254 free_string(name);
2255 name = tmp_name;
2256 sym = tmp_sym;
2257 }
2258
2259 if (op == PARAM_LIMIT)
2260 set_extra_nomod_vsl(name, sym, vsl, alloc_estate_rl(new));
2261 else
2262 set_extra_mod(name, sym, alloc_estate_rl(new));
2263 }
2264
2265 free:
2266 free_string(name);
2267 }
2268
2269 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
2270 {
2271 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
2272 }
2273
2274 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
2275 {
2276 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
2277 }
2278
2279 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
2280 {
2281 struct expression *arg;
2282 char *name, *tmp_name;
2283 struct symbol *sym, *tmp_sym;
2284 struct symbol *type;
2285 struct smatch_state *state;
2286 struct range_list *new = NULL;
2287 struct range_list *added = NULL;
2288
2289 while (expr->type == EXPR_ASSIGNMENT)
2290 expr = strip_expr(expr->right);
2291 if (expr->type != EXPR_CALL)
2292 return;
2293
2294 arg = get_argument_from_call_expr(expr->args, param);
2295 if (!arg)
2296 return;
2297 type = get_member_type_from_key(arg, key);
2298 name = get_variable_from_key(arg, key, &sym);
2299 if (!name || !sym)
2300 goto free;
2301
2302 state = get_state(SMATCH_EXTRA, name, sym);
2303 if (state)
2304 new = estate_rl(state);
2305
2306 call_results_to_rl(expr, type, value, &added);
2307
2308 if (op == PARAM_SET)
2309 new = added;
2310 else
2311 new = rl_union(new, added);
2312
2313 tmp_name = map_long_to_short_name_sym_nostack(name, sym, &tmp_sym);
2314 if (tmp_name && tmp_sym) {
2315 free_string(name);
2316 name = tmp_name;
2317 sym = tmp_sym;
2318 }
2319 set_extra_mod(name, sym, alloc_estate_rl(new));
2320 free:
2321 free_string(name);
2322 }
2323
2324 static void db_param_add(struct expression *expr, int param, char *key, char *value)
2325 {
2326 in_param_set = true;
2327 db_param_add_set(expr, param, key, value, PARAM_ADD);
2328 in_param_set = false;
2329 }
2330
2331 static void db_param_set(struct expression *expr, int param, char *key, char *value)
2332 {
2333 in_param_set = true;
2334 db_param_add_set(expr, param, key, value, PARAM_SET);
2335 in_param_set = false;
2336 }
2337
2338 static void db_param_value(struct expression *expr, int param, char *key, char *value)
2339 {
2340 struct expression *call;
2341 char *name;
2342 struct symbol *sym;
2343 struct symbol *type;
2344 struct range_list *rl = NULL;
2345
2346 if (param != -1)
2347 return;
2348
2349 call = expr;
2350 while (call->type == EXPR_ASSIGNMENT)
2351 call = strip_expr(call->right);
2352 if (call->type != EXPR_CALL)
2353 return;
2354
2355 type = get_member_type_from_key(expr->left, key);
2356 name = get_variable_from_key(expr->left, key, &sym);
2357 if (!name || !sym)
2358 goto free;
2359
2360 call_results_to_rl(call, type, value, &rl);
2361
2362 set_extra_mod(name, sym, alloc_estate_rl(rl));
2363 free:
2364 free_string(name);
2365 }
2366
2367 static void match_call_info(struct expression *expr)
2368 {
2369 struct smatch_state *state;
2370 struct range_list *rl = NULL;
2371 struct expression *arg;
2372 struct symbol *type;
2373 int i = 0;
2374
2375 FOR_EACH_PTR(expr->args, arg) {
2376 type = get_arg_type(expr->fn, i);
2377
2378 if (get_implied_rl(arg, &rl))
2379 rl = cast_rl(type, rl);
2380 else
2381 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
2382
2383 if (!is_whole_rl(rl)) {
2384 rl = intersect_with_real_abs_expr(arg, rl);
2385 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
2386 }
2387 state = get_state_expr(SMATCH_EXTRA, arg);
2388 if (estate_has_fuzzy_max(state)) {
2389 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
2390 sval_to_str(estate_get_fuzzy_max(state)));
2391 }
2392 i++;
2393 } END_FOR_EACH_PTR(arg);
2394 }
2395
2396 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2397 {
2398 struct range_list *rl = NULL;
2399 struct smatch_state *state;
2400 struct symbol *type;
2401 char fullname[256];
2402 sval_t dummy;
2403
2404 if (strcmp(key, "*$") == 0)
2405 snprintf(fullname, sizeof(fullname), "*%s", name);
2406 else if (strncmp(key, "$", 1) == 0)
2407 snprintf(fullname, 256, "%s%s", name, key + 1);
2408 else
2409 return;
2410
2411 type = get_member_type_from_key(symbol_expression(sym), key);
2412 str_to_rl(type, value, &rl);
2413 state = alloc_estate_rl(rl);
2414 if (estate_get_single_value(state, &dummy))
2415 estate_set_hard_max(state);
2416 set_state(SMATCH_EXTRA, fullname, sym, state);
2417 }
2418
2419 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2420 {
2421 struct range_list *rl = NULL;
2422 struct smatch_state *state;
2423 struct symbol *type;
2424 char fullname[256];
2425 sval_t max;
2426
2427 if (strcmp(key, "*$") == 0)
2428 snprintf(fullname, sizeof(fullname), "*%s", name);
2429 else if (strncmp(key, "$", 1) == 0)
2430 snprintf(fullname, 256, "%s%s", name, key + 1);
2431 else
2432 return;
2433
2434 state = get_state(SMATCH_EXTRA, fullname, sym);
2435 if (!state)
2436 return;
2437 type = get_member_type_from_key(symbol_expression(sym), key);
2438 str_to_rl(type, value, &rl);
2439 if (!rl_to_sval(rl, &max))
2440 return;
2441 estate_set_fuzzy_max(state, max);
2442 }
2443
2444 struct smatch_state *get_extra_state(struct expression *expr)
2445 {
2446 char *name;
2447 struct symbol *sym;
2448 struct smatch_state *ret = NULL;
2449 struct range_list *rl;
2450
2451 if (is_pointer(expr) && get_address_rl(expr, &rl))
2452 return alloc_estate_rl(rl);
2453
2454 name = expr_to_known_chunk_sym(expr, &sym);
2455 if (!name)
2456 goto free;
2457
2458 ret = get_state(SMATCH_EXTRA, name, sym);
2459 free:
2460 free_string(name);
2461 return ret;
2462 }
2463
2464 void register_smatch_extra(int id)
2465 {
2466 my_id = id;
2467
2468 add_merge_hook(my_id, &merge_estates);
2469 add_unmatched_state_hook(my_id, &unmatched_state);
2470 select_caller_info_hook(set_param_value, PARAM_VALUE);
2471 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
2472 select_return_states_before(&db_limited_before);
2473 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2474 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2475 select_return_states_hook(PARAM_ADD, &db_param_add);
2476 select_return_states_hook(PARAM_SET, &db_param_set);
2477 select_return_states_hook(PARAM_VALUE, &db_param_value);
2478 select_return_states_after(&db_limited_after);
2479 }
2480
2481 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2482 {
2483 struct var_sym_list *links;
2484 struct var_sym *tmp;
2485 struct smatch_state *state;
2486
2487 links = sm->state->data;
2488
2489 FOR_EACH_PTR(links, tmp) {
2490 if (sm->sym == tmp->sym &&
2491 strcmp(sm->name, tmp->var) == 0)
2492 continue;
2493 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2494 if (!state)
2495 continue;
2496 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2497 } END_FOR_EACH_PTR(tmp);
2498 set_state(link_id, sm->name, sm->sym, &undefined);
2499 }
2500
2501 void register_smatch_extra_links(int id)
2502 {
2503 link_id = id;
2504 }
2505
2506 void register_smatch_extra_late(int id)
2507 {
2508 add_merge_hook(link_id, &merge_link_states);
2509 add_modification_hook(link_id, &match_link_modify);
2510 add_hook(&match_dereferences, DEREF_HOOK);
2511 add_hook(&match_pointer_as_array, OP_HOOK);
2512 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
2513 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2514 add_hook(&match_assign, ASSIGNMENT_HOOK);
2515 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2516 add_hook(&unop_expr, OP_HOOK);
2517 add_hook(&asm_expr, ASM_HOOK);
2518 add_untracked_param_hook(&match_untracked_array);
2519
2520 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
2521 add_member_info_callback(my_id, struct_member_callback);
2522 add_split_return_callback(&returned_struct_members);
2523
2524 add_hook(&assume_indexes_are_valid, OP_HOOK);
2525 }
Static analysis for C