?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
buf_size: fix recording global sizes
[smatch.git] / smatch_extra.c
blob6cfc6c0cc6a78ecbdf0a957f3b51725e838080fb
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 expression *expr, 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 expression *expr, struct smatch_state *state)
83 {
84 mod_hook **fn;
85
86 FOR_EACH_PTR(hooks, fn) {
87 (*fn)(name, sym, expr, state);
88 } END_FOR_EACH_PTR(fn);
89 }
90
91 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
92 {
93 call_extra_hooks(extra_mod_hooks, name, sym, expr, state);
94 }
95
96 void call_extra_nomod_hooks(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
97 {
98 call_extra_hooks(extra_nomod_hooks, name, sym, expr, state);
99 }
100
101 static bool in_param_set;
102 void set_extra_mod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
103 {
104 remove_from_equiv(name, sym);
105 call_extra_mod_hooks(name, sym, expr, 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 expression *expr, struct smatch_state *state)
113 {
114 call_extra_nomod_hooks(name, sym, expr, 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 expression *expr, struct smatch_state *state)
194 {
195 char *new_name;
196 struct symbol *new_sym;
197
198 set_extra_mod_helper(name, sym, expr, 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, expr, state);
202 free_string(new_name);
203 }
204
205 static struct expression *chunk_get_array_base(struct expression *expr)
206 {
207 /*
208 * The problem with is_array() is that it only returns true for things
209 * like foo[1] but not for foo[1].bar.
210 *
211 */
212 expr = strip_expr(expr);
213 while (expr && expr->type == EXPR_DEREF)
214 expr = strip_expr(expr->deref);
215 return get_array_base(expr);
216 }
217
218 static int chunk_has_array(struct expression *expr)
219 {
220 return !!chunk_get_array_base(expr);
221 }
222
223 static void clear_array_states(struct expression *array)
224 {
225 struct sm_state *sm;
226
227 sm = get_sm_state_expr(link_id, array);
228 if (sm)
229 match_link_modify(sm, NULL);
230 }
231
232 static void set_extra_array_mod(struct expression *expr, struct smatch_state *state)
233 {
234 struct expression *array;
235 struct var_sym_list *vsl;
236 struct var_sym *vs;
237 char *name;
238 struct symbol *sym;
239
240 array = chunk_get_array_base(expr);
241
242 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
243 if (!name || !vsl) {
244 clear_array_states(array);
245 goto free;
246 }
247
248 FOR_EACH_PTR(vsl, vs) {
249 store_link(link_id, vs->var, vs->sym, name, sym);
250 } END_FOR_EACH_PTR(vs);
251
252 call_extra_mod_hooks(name, sym, expr, state);
253 set_state(SMATCH_EXTRA, name, sym, state);
254 free:
255 free_string(name);
256 }
257
258 void set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
259 {
260 struct symbol *sym;
261 char *name;
262
263 if (chunk_has_array(expr)) {
264 set_extra_array_mod(expr, state);
265 return;
266 }
267
268 expr = strip_expr(expr);
269 name = expr_to_var_sym(expr, &sym);
270 if (!name || !sym)
271 goto free;
272 set_extra_mod(name, sym, expr, state);
273 free:
274 free_string(name);
275 }
276
277 void set_extra_nomod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
278 {
279 char *new_name;
280 struct symbol *new_sym;
281 struct relation *rel;
282 struct smatch_state *orig_state;
283
284 orig_state = get_state(SMATCH_EXTRA, name, sym);
285
286 /* don't save unknown states if leaving it blank is the same */
287 if (!orig_state && estate_is_unknown(state))
288 return;
289
290 new_name = get_other_name_sym(name, sym, &new_sym);
291 if (new_name && new_sym)
292 set_extra_nomod_helper(new_name, new_sym, expr, state);
293 free_string(new_name);
294
295 if (!estate_related(orig_state)) {
296 set_extra_nomod_helper(name, sym, expr, state);
297 return;
298 }
299
300 set_related(state, estate_related(orig_state));
301 FOR_EACH_PTR(estate_related(orig_state), rel) {
302 struct smatch_state *estate;
303
304 if (option_debug_related)
305 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
306 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
307 if (!estate)
308 continue;
309 set_extra_nomod_helper(rel->name, rel->sym, expr, clone_estate_cast(estate_type(estate), state));
310 } END_FOR_EACH_PTR(rel);
311 }
312
313 void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct expression *expr, struct smatch_state *state)
314 {
315 struct var_sym *vs;
316
317 FOR_EACH_PTR(vsl, vs) {
318 store_link(link_id, vs->var, vs->sym, name, sym);
319 } END_FOR_EACH_PTR(vs);
320
321 set_extra_nomod(name, sym, expr, state);
322 }
323
324 /*
325 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
326 */
327 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
328 {
329 struct var_sym_list *vsl;
330 struct var_sym *vs;
331 char *name;
332 struct symbol *sym;
333
334 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
335 if (!name || !vsl)
336 goto free;
337 FOR_EACH_PTR(vsl, vs) {
338 store_link(link_id, vs->var, vs->sym, name, sym);
339 } END_FOR_EACH_PTR(vs);
340
341 set_extra_nomod(name, sym, expr, state);
342 free:
343 free_string(name);
344 }
345
346 static void set_extra_true_false(const char *name, struct symbol *sym,
347 struct smatch_state *true_state,
348 struct smatch_state *false_state)
349 {
350 char *new_name;
351 struct symbol *new_sym;
352 struct relation *rel;
353 struct smatch_state *orig_state;
354
355 if (!true_state && !false_state)
356 return;
357
358 if (in_warn_on_macro())
359 return;
360
361 new_name = get_other_name_sym(name, sym, &new_sym);
362 if (new_name && new_sym)
363 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
364 free_string(new_name);
365
366 orig_state = get_state(SMATCH_EXTRA, name, sym);
367
368 if (!estate_related(orig_state)) {
369 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
370 return;
371 }
372
373 if (true_state)
374 set_related(true_state, estate_related(orig_state));
375 if (false_state)
376 set_related(false_state, estate_related(orig_state));
377
378 FOR_EACH_PTR(estate_related(orig_state), rel) {
379 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
380 true_state, false_state);
381 } END_FOR_EACH_PTR(rel);
382 }
383
384 static void set_extra_chunk_true_false(struct expression *expr,
385 struct smatch_state *true_state,
386 struct smatch_state *false_state)
387 {
388 struct var_sym_list *vsl;
389 struct var_sym *vs;
390 struct symbol *type;
391 char *name;
392 struct symbol *sym;
393
394 if (in_warn_on_macro())
395 return;
396
397 type = get_type(expr);
398 if (!type)
399 return;
400
401 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
402 if (!name || !vsl)
403 goto free;
404 FOR_EACH_PTR(vsl, vs) {
405 store_link(link_id, vs->var, vs->sym, name, sym);
406 } END_FOR_EACH_PTR(vs);
407
408 set_true_false_states(SMATCH_EXTRA, name, sym,
409 clone_estate(true_state),
410 clone_estate(false_state));
411 free:
412 free_string(name);
413 }
414
415 static void set_extra_expr_true_false(struct expression *expr,
416 struct smatch_state *true_state,
417 struct smatch_state *false_state)
418 {
419 char *name;
420 struct symbol *sym;
421 sval_t sval;
422
423 if (!true_state && !false_state)
424 return;
425
426 if (get_value(expr, &sval))
427 return;
428
429 expr = strip_expr(expr);
430 name = expr_to_var_sym(expr, &sym);
431 if (!name || !sym) {
432 free_string(name);
433 set_extra_chunk_true_false(expr, true_state, false_state);
434 return;
435 }
436 set_extra_true_false(name, sym, true_state, false_state);
437 free_string(name);
438 }
439
440 static int get_countdown_info(struct expression *condition, struct expression **unop, int *op, sval_t *right)
441 {
442 struct expression *unop_expr;
443 int comparison;
444 sval_t limit;
445
446 right->type = &int_ctype;
447 right->value = 0;
448
449 condition = strip_expr(condition);
450
451 if (condition->type == EXPR_COMPARE) {
452 comparison = remove_unsigned_from_comparison(condition->op);
453
454 if (comparison != SPECIAL_GTE && comparison != '>')
455 return 0;
456 if (!get_value(condition->right, &limit))
457 return 0;
458
459 unop_expr = condition->left;
460 if (unop_expr->type != EXPR_PREOP && unop_expr->type != EXPR_POSTOP)
461 return 0;
462 if (unop_expr->op != SPECIAL_DECREMENT)
463 return 0;
464
465 *unop = unop_expr;
466 *op = comparison;
467 *right = limit;
468
469 return 1;
470 }
471
472 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
473 return 0;
474 if (condition->op != SPECIAL_DECREMENT)
475 return 0;
476
477 *unop = condition;
478 *op = '>';
479
480 return 1;
481 }
482
483 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
484 {
485 struct expression *iter_var;
486 struct expression *condition, *unop;
487 struct sm_state *sm;
488 struct smatch_state *estate;
489 int op;
490 sval_t start, right;
491
492 right.type = &int_ctype;
493 right.value = 0;
494
495 condition = strip_expr(loop->iterator_pre_condition);
496 if (!condition)
497 return NULL;
498
499 if (!get_countdown_info(condition, &unop, &op, &right))
500 return NULL;
501
502 iter_var = unop->unop;
503
504 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
505 if (!sm)
506 return NULL;
507 if (sval_cmp(estate_min(sm->state), right) < 0)
508 return NULL;
509 start = estate_max(sm->state);
510 if (sval_cmp(start, right) <= 0)
511 return NULL;
512 if (!sval_is_max(start))
513 start.value--;
514
515 if (op == SPECIAL_GTE)
516 right.value--;
517
518 if (unop->type == EXPR_PREOP) {
519 right.value++;
520 estate = alloc_estate_range(right, start);
521 if (estate_has_hard_max(sm->state))
522 estate_set_hard_max(estate);
523 estate_copy_fuzzy_max(estate, sm->state);
524 set_extra_expr_mod(iter_var, estate);
525 }
526 if (unop->type == EXPR_POSTOP) {
527 estate = alloc_estate_range(right, start);
528 if (estate_has_hard_max(sm->state))
529 estate_set_hard_max(estate);
530 estate_copy_fuzzy_max(estate, sm->state);
531 set_extra_expr_mod(iter_var, estate);
532 }
533 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
534 }
535
536 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
537 struct expression *condition)
538 {
539 struct expression *iter_var;
540 struct sm_state *sm;
541 struct smatch_state *estate;
542 sval_t start, end, max;
543
544 iter_var = iter_expr->unop;
545 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
546 if (!sm)
547 return NULL;
548 if (!estate_get_single_value(sm->state, &start))
549 return NULL;
550 if (get_implied_max(condition->right, &end))
551 end = sval_cast(get_type(iter_var), end);
552 else
553 end = sval_type_max(get_type(iter_var));
554
555 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
556 return NULL;
557
558 switch (condition->op) {
559 case SPECIAL_UNSIGNED_LT:
560 case SPECIAL_NOTEQUAL:
561 case '<':
562 if (!sval_is_min(end))
563 end.value--;
564 break;
565 case SPECIAL_UNSIGNED_LTE:
566 case SPECIAL_LTE:
567 break;
568 default:
569 return NULL;
570 }
571 if (sval_cmp(end, start) < 0)
572 return NULL;
573 estate = alloc_estate_range(start, end);
574 if (get_hard_max(condition->right, &max)) {
575 estate_set_hard_max(estate);
576 if (condition->op == '<' ||
577 condition->op == SPECIAL_UNSIGNED_LT ||
578 condition->op == SPECIAL_NOTEQUAL)
579 max.value--;
580 estate_set_fuzzy_max(estate, max);
581 }
582 set_extra_expr_mod(iter_var, estate);
583 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
584 }
585
586 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
587 struct expression *condition)
588 {
589 struct expression *iter_var;
590 struct sm_state *sm;
591 struct smatch_state *estate;
592 sval_t start, end;
593
594 iter_var = iter_expr->unop;
595 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
596 if (!sm)
597 return NULL;
598 if (!estate_get_single_value(sm->state, &start))
599 return NULL;
600 if (!get_implied_min(condition->right, &end))
601 end = sval_type_min(get_type(iter_var));
602 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
603 return NULL;
604
605 switch (condition->op) {
606 case SPECIAL_NOTEQUAL:
607 case '>':
608 if (!sval_is_min(end) && !sval_is_max(end))
609 end.value++;
610 break;
611 case SPECIAL_GTE:
612 break;
613 default:
614 return NULL;
615 }
616 if (sval_cmp(end, start) > 0)
617 return NULL;
618 estate = alloc_estate_range(end, start);
619 estate_set_hard_max(estate);
620 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
621 set_extra_expr_mod(iter_var, estate);
622 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
623 }
624
625 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
626 {
627 struct expression *iter_expr;
628 struct expression *condition;
629
630 if (!loop->iterator_post_statement)
631 return NULL;
632 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
633 return NULL;
634 iter_expr = loop->iterator_post_statement->expression;
635 if (!loop->iterator_pre_condition)
636 return NULL;
637 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
638 return NULL;
639 condition = loop->iterator_pre_condition;
640
641 if (iter_expr->op == SPECIAL_INCREMENT)
642 return handle_canonical_for_inc(iter_expr, condition);
643 if (iter_expr->op == SPECIAL_DECREMENT)
644 return handle_canonical_for_dec(iter_expr, condition);
645 return NULL;
646 }
647
648 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
649 {
650 struct sm_state *ret;
651
652 /*
653 * Canonical loops are a hack. The proper way to handle this is to
654 * use two passes, but unfortunately, doing two passes makes parsing
655 * code twice as slow.
656 *
657 * What we do is we set the inside state here, which overwrites whatever
658 * __extra_match_condition() does. Then we set the outside state in
659 * __extra_pre_loop_hook_after().
660 *
661 */
662 __push_fake_cur_stree();
663 if (!loop->iterator_post_statement)
664 ret = handle_canonical_while_count_down(loop);
665 else
666 ret = handle_canonical_for_loops(loop);
667 *stree = __pop_fake_cur_stree();
668 return ret;
669 }
670
671 int __iterator_unchanged(struct sm_state *sm)
672 {
673 if (!sm)
674 return 0;
675 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
676 return 1;
677 return 0;
678 }
679
680 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
681 {
682 struct expression *unop;
683 int op;
684 sval_t limit, after_value;
685
686 if (!get_countdown_info(condition, &unop, &op, &limit))
687 return;
688 after_value = estate_min(sm->state);
689 after_value.value--;
690 set_extra_mod(sm->name, sm->sym, condition->unop, alloc_estate_sval(after_value));
691 }
692
693 void __extra_pre_loop_hook_after(struct sm_state *sm,
694 struct statement *iterator,
695 struct expression *condition)
696 {
697 struct expression *iter_expr;
698 sval_t limit;
699 struct smatch_state *state;
700
701 if (!iterator) {
702 while_count_down_after(sm, condition);
703 return;
704 }
705
706 iter_expr = iterator->expression;
707
708 if (condition->type != EXPR_COMPARE)
709 return;
710 if (iter_expr->op == SPECIAL_INCREMENT) {
711 limit = sval_binop(estate_max(sm->state), '+',
712 sval_type_val(estate_type(sm->state), 1));
713 } else {
714 limit = sval_binop(estate_min(sm->state), '-',
715 sval_type_val(estate_type(sm->state), 1));
716 }
717 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
718 if (iter_expr->op == SPECIAL_INCREMENT)
719 state = alloc_estate_range(estate_min(sm->state), limit);
720 else
721 state = alloc_estate_range(limit, estate_max(sm->state));
722 } else {
723 state = alloc_estate_sval(limit);
724 }
725 if (!estate_has_hard_max(sm->state)) {
726 estate_clear_hard_max(state);
727 }
728 if (estate_has_fuzzy_max(sm->state)) {
729 sval_t hmax = estate_get_fuzzy_max(sm->state);
730 sval_t max = estate_max(sm->state);
731
732 if (sval_cmp(hmax, max) != 0)
733 estate_clear_fuzzy_max(state);
734 } else if (!estate_has_fuzzy_max(sm->state)) {
735 estate_clear_fuzzy_max(state);
736 }
737
738 set_extra_mod(sm->name, sm->sym, iter_expr, state);
739 }
740
741 static struct stree *unmatched_stree;
742 static struct smatch_state *unmatched_state(struct sm_state *sm)
743 {
744 struct smatch_state *state;
745
746 if (unmatched_stree) {
747 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
748 if (state)
749 return state;
750 }
751 if (parent_is_gone_var_sym(sm->name, sm->sym))
752 return alloc_estate_empty();
753 return alloc_estate_whole(estate_type(sm->state));
754 }
755
756 static void clear_the_pointed_at(struct expression *expr)
757 {
758 struct stree *stree;
759 char *name;
760 struct symbol *sym;
761 struct sm_state *tmp;
762
763 name = expr_to_var_sym(expr, &sym);
764 if (!name || !sym)
765 goto free;
766
767 stree = __get_cur_stree();
768 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
769 if (tmp->name[0] != '*')
770 continue;
771 if (tmp->sym != sym)
772 continue;
773 if (strcmp(tmp->name + 1, name) != 0)
774 continue;
775 set_extra_mod(tmp->name, tmp->sym, expr, alloc_estate_whole(estate_type(tmp->state)));
776 } END_FOR_EACH_SM(tmp);
777
778 free:
779 free_string(name);
780 }
781
782 static int is_const_param(struct expression *expr, int param)
783 {
784 struct symbol *type;
785
786 type = get_arg_type(expr, param);
787 if (!type)
788 return 0;
789 if (type->ctype.modifiers & MOD_CONST)
790 return 1;
791 return 0;
792 }
793
794 static void match_function_call(struct expression *expr)
795 {
796 struct expression *arg;
797 struct expression *tmp;
798 int param = -1;
799
800 /* if we have the db this is handled in smatch_function_hooks.c */
801 if (!option_no_db)
802 return;
803 if (inlinable(expr->fn))
804 return;
805
806 FOR_EACH_PTR(expr->args, arg) {
807 param++;
808 if (is_const_param(expr->fn, param))
809 continue;
810 tmp = strip_expr(arg);
811 if (tmp->type == EXPR_PREOP && tmp->op == '&')
812 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
813 else
814 clear_the_pointed_at(tmp);
815 } END_FOR_EACH_PTR(arg);
816 }
817
818 static int values_fit_type(struct expression *left, struct expression *right)
819 {
820 struct range_list *rl;
821 struct symbol *type;
822
823 type = get_type(left);
824 if (!type)
825 return 0;
826 get_absolute_rl(right, &rl);
827 if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
828 return 0;
829 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
830 return 0;
831 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
832 return 0;
833 return 1;
834 }
835
836 static void save_chunk_info(struct expression *left, struct expression *right)
837 {
838 struct var_sym_list *vsl;
839 struct var_sym *vs;
840 struct expression *add_expr;
841 struct symbol *type;
842 sval_t sval;
843 char *name;
844 struct symbol *sym;
845
846 if (right->type != EXPR_BINOP || right->op != '-')
847 return;
848 if (!get_value(right->left, &sval))
849 return;
850 if (!expr_to_sym(right->right))
851 return;
852
853 add_expr = binop_expression(left, '+', right->right);
854 type = get_type(add_expr);
855 if (!type)
856 return;
857 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
858 if (!name || !vsl)
859 goto free;
860 FOR_EACH_PTR(vsl, vs) {
861 store_link(link_id, vs->var, vs->sym, name, sym);
862 } END_FOR_EACH_PTR(vs);
863
864 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
865 free:
866 free_string(name);
867 }
868
869 static void do_array_assign(struct expression *left, int op, struct expression *right)
870 {
871 struct range_list *rl;
872
873 if (op == '=') {
874 get_absolute_rl(right, &rl);
875 rl = cast_rl(get_type(left), rl);
876 } else {
877 rl = alloc_whole_rl(get_type(left));
878 }
879
880 set_extra_array_mod(left, alloc_estate_rl(rl));
881 }
882
883 static void match_vanilla_assign(struct expression *left, struct expression *right)
884 {
885 struct range_list *orig_rl = NULL;
886 struct range_list *rl = NULL;
887 struct symbol *right_sym;
888 struct symbol *left_type;
889 struct symbol *right_type;
890 char *right_name = NULL;
891 struct symbol *sym;
892 char *name;
893 sval_t sval, max;
894 struct smatch_state *state;
895 int comparison;
896
897 if (is_struct(left))
898 return;
899
900 save_chunk_info(left, right);
901
902 name = expr_to_var_sym(left, &sym);
903 if (!name) {
904 if (chunk_has_array(left))
905 do_array_assign(left, '=', right);
906 return;
907 }
908
909 left_type = get_type(left);
910 right_type = get_type(right);
911
912 right_name = expr_to_var_sym(right, &right_sym);
913
914 if (!__in_fake_assign &&
915 !(right->type == EXPR_PREOP && right->op == '&') &&
916 right_name && right_sym &&
917 values_fit_type(left, strip_expr(right)) &&
918 !has_symbol(right, sym)) {
919 set_equiv(left, right);
920 goto free;
921 }
922
923 if (is_pointer(right) && get_address_rl(right, &rl)) {
924 state = alloc_estate_rl(rl);
925 goto done;
926 }
927
928 if (get_implied_value(right, &sval)) {
929 state = alloc_estate_sval(sval_cast(left_type, sval));
930 goto done;
931 }
932
933 if (__in_fake_assign) {
934 struct smatch_state *right_state;
935 sval_t sval;
936
937 if (get_value(right, &sval)) {
938 sval = sval_cast(left_type, sval);
939 state = alloc_estate_sval(sval);
940 goto done;
941 }
942
943 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
944 if (right_state) {
945 /* simple assignment */
946 state = clone_estate(right_state);
947 goto done;
948 }
949
950 state = alloc_estate_rl(alloc_whole_rl(left_type));
951 goto done;
952 }
953
954 comparison = get_comparison(left, right);
955 if (comparison) {
956 comparison = flip_comparison(comparison);
957 get_implied_rl(left, &orig_rl);
958 }
959
960 if (get_implied_rl(right, &rl)) {
961 rl = cast_rl(left_type, rl);
962 if (orig_rl)
963 filter_by_comparison(&rl, comparison, orig_rl);
964 state = alloc_estate_rl(rl);
965 if (get_hard_max(right, &max)) {
966 estate_set_hard_max(state);
967 estate_set_fuzzy_max(state, max);
968 }
969 } else {
970 rl = alloc_whole_rl(right_type);
971 rl = cast_rl(left_type, rl);
972 if (orig_rl)
973 filter_by_comparison(&rl, comparison, orig_rl);
974 state = alloc_estate_rl(rl);
975 }
976
977 done:
978 set_extra_mod(name, sym, left, state);
979 free:
980 free_string(right_name);
981 }
982
983 static int op_remove_assign(int op)
984 {
985 switch (op) {
986 case SPECIAL_ADD_ASSIGN:
987 return '+';
988 case SPECIAL_SUB_ASSIGN:
989 return '-';
990 case SPECIAL_MUL_ASSIGN:
991 return '*';
992 case SPECIAL_DIV_ASSIGN:
993 return '/';
994 case SPECIAL_MOD_ASSIGN:
995 return '%';
996 case SPECIAL_AND_ASSIGN:
997 return '&';
998 case SPECIAL_OR_ASSIGN:
999 return '|';
1000 case SPECIAL_XOR_ASSIGN:
1001 return '^';
1002 case SPECIAL_SHL_ASSIGN:
1003 return SPECIAL_LEFTSHIFT;
1004 case SPECIAL_SHR_ASSIGN:
1005 return SPECIAL_RIGHTSHIFT;
1006 default:
1007 return op;
1008 }
1009 }
1010
1011 static void match_assign(struct expression *expr)
1012 {
1013 struct range_list *rl = NULL;
1014 struct expression *left;
1015 struct expression *right;
1016 struct expression *binop_expr;
1017 struct symbol *left_type;
1018 struct symbol *sym;
1019 char *name;
1020 sval_t left_min, left_max;
1021 sval_t right_min, right_max;
1022 sval_t res_min, res_max;
1023
1024 left = strip_expr(expr->left);
1025
1026 right = strip_parens(expr->right);
1027 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
1028 right = get_argument_from_call_expr(right->args, 0);
1029 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
1030 right = strip_parens(right->left);
1031
1032 if (expr->op == '=' && is_condition(expr->right))
1033 return; /* handled in smatch_condition.c */
1034 if (expr->op == '=' && right->type == EXPR_CALL)
1035 return; /* handled in smatch_function_hooks.c */
1036 if (expr->op == '=') {
1037 match_vanilla_assign(left, right);
1038 return;
1039 }
1040
1041 name = expr_to_var_sym(left, &sym);
1042 if (!name)
1043 return;
1044
1045 left_type = get_type(left);
1046
1047 res_min = sval_type_min(left_type);
1048 res_max = sval_type_max(left_type);
1049
1050 switch (expr->op) {
1051 case SPECIAL_ADD_ASSIGN:
1052 get_absolute_max(left, &left_max);
1053 get_absolute_max(right, &right_max);
1054 if (sval_binop_overflows(left_max, '+', sval_cast(left_type, right_max)))
1055 break;
1056 if (get_implied_min(left, &left_min) &&
1057 !sval_is_negative_min(left_min) &&
1058 get_implied_min(right, &right_min) &&
1059 !sval_is_negative_min(right_min)) {
1060 res_min = sval_binop(left_min, '+', right_min);
1061 res_min = sval_cast(left_type, res_min);
1062 }
1063 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
1064 break;
1065 res_max = sval_binop(left_max, '+', right_max);
1066 res_max = sval_cast(left_type, res_max);
1067 break;
1068 case SPECIAL_SUB_ASSIGN:
1069 if (get_implied_max(left, &left_max) &&
1070 !sval_is_max(left_max) &&
1071 get_implied_min(right, &right_min) &&
1072 !sval_is_min(right_min)) {
1073 res_max = sval_binop(left_max, '-', right_min);
1074 res_max = sval_cast(left_type, res_max);
1075 }
1076 if (inside_loop())
1077 break;
1078 if (get_implied_min(left, &left_min) &&
1079 !sval_is_min(left_min) &&
1080 get_implied_max(right, &right_max) &&
1081 !sval_is_max(right_max)) {
1082 res_min = sval_binop(left_min, '-', right_max);
1083 res_min = sval_cast(left_type, res_min);
1084 }
1085 break;
1086 case SPECIAL_AND_ASSIGN:
1087 case SPECIAL_MOD_ASSIGN:
1088 case SPECIAL_SHL_ASSIGN:
1089 case SPECIAL_SHR_ASSIGN:
1090 case SPECIAL_OR_ASSIGN:
1091 case SPECIAL_XOR_ASSIGN:
1092 case SPECIAL_MUL_ASSIGN:
1093 case SPECIAL_DIV_ASSIGN:
1094 binop_expr = binop_expression(expr->left,
1095 op_remove_assign(expr->op),
1096 expr->right);
1097 if (get_absolute_rl(binop_expr, &rl)) {
1098 rl = cast_rl(left_type, rl);
1099 set_extra_mod(name, sym, left, alloc_estate_rl(rl));
1100 goto free;
1101 }
1102 break;
1103 }
1104 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
1105 set_extra_mod(name, sym, left, alloc_estate_rl(rl));
1106 free:
1107 free_string(name);
1108 }
1109
1110 static struct smatch_state *increment_state(struct smatch_state *state)
1111 {
1112 sval_t min = estate_min(state);
1113 sval_t max = estate_max(state);
1114
1115 if (!estate_rl(state))
1116 return NULL;
1117
1118 if (inside_loop())
1119 max = sval_type_max(max.type);
1120
1121 if (!sval_is_min(min) && !sval_is_max(min))
1122 min.value++;
1123 if (!sval_is_min(max) && !sval_is_max(max))
1124 max.value++;
1125 return alloc_estate_range(min, max);
1126 }
1127
1128 static struct smatch_state *decrement_state(struct smatch_state *state)
1129 {
1130 sval_t min = estate_min(state);
1131 sval_t max = estate_max(state);
1132
1133 if (!estate_rl(state))
1134 return NULL;
1135
1136 if (inside_loop())
1137 min = sval_type_min(min.type);
1138
1139 if (!sval_is_min(min) && !sval_is_max(min))
1140 min.value--;
1141 if (!sval_is_min(max) && !sval_is_max(max))
1142 max.value--;
1143 return alloc_estate_range(min, max);
1144 }
1145
1146 static void clear_pointed_at_state(struct expression *expr)
1147 {
1148 struct symbol *type;
1149
1150 /*
1151 * ALERT: This is sort of a mess. If it's is a struct assigment like
1152 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1153 * the same thing for p++ where "p" is a struct. Most modifications
1154 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1155 * use smatch_modification.c because we have to get the ordering right
1156 * or something. So if you have p++ where p is a pointer to a standard
1157 * c type then we handle that here. What a mess.
1158 */
1159
1160 type = get_type(expr);
1161 if (!type || type->type != SYM_PTR)
1162 return;
1163 type = get_real_base_type(type);
1164 if (!type || type->type != SYM_BASETYPE)
1165 return;
1166 set_extra_expr_mod(deref_expression(expr), alloc_estate_whole(type));
1167 }
1168
1169 static void unop_expr(struct expression *expr)
1170 {
1171 struct smatch_state *state;
1172
1173 if (expr->smatch_flags & Handled)
1174 return;
1175
1176 switch (expr->op) {
1177 case SPECIAL_INCREMENT:
1178 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1179 state = increment_state(state);
1180 if (!state)
1181 state = alloc_estate_whole(get_type(expr));
1182 set_extra_expr_mod(expr->unop, state);
1183 clear_pointed_at_state(expr->unop);
1184 break;
1185 case SPECIAL_DECREMENT:
1186 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1187 state = decrement_state(state);
1188 if (!state)
1189 state = alloc_estate_whole(get_type(expr));
1190 set_extra_expr_mod(expr->unop, state);
1191 clear_pointed_at_state(expr->unop);
1192 break;
1193 default:
1194 return;
1195 }
1196 }
1197
1198 static void asm_expr(struct statement *stmt)
1199 {
1200
1201 struct expression *expr;
1202 struct symbol *type;
1203 int state = 0;
1204
1205 FOR_EACH_PTR(stmt->asm_outputs, expr) {
1206 switch (state) {
1207 case 0: /* identifier */
1208 case 1: /* constraint */
1209 state++;
1210 continue;
1211 case 2: /* expression */
1212 state = 0;
1213 type = get_type(strip_expr(expr));
1214 set_extra_expr_mod(expr, alloc_estate_whole(type));
1215 continue;
1216 }
1217 } END_FOR_EACH_PTR(expr);
1218 }
1219
1220 static void check_dereference(struct expression *expr)
1221 {
1222 struct smatch_state *state;
1223
1224 if (__in_fake_assign)
1225 return;
1226 if (outside_of_function())
1227 return;
1228 state = get_extra_state(expr);
1229 if (state) {
1230 static struct range_list *valid_rl;
1231 struct range_list *rl;
1232
1233 if (!valid_rl) {
1234 valid_rl = alloc_rl(valid_ptr_min_sval, valid_ptr_max_sval);
1235 valid_rl = clone_rl_permanent(valid_rl);
1236 }
1237
1238 rl = rl_intersection(estate_rl(state), valid_rl);
1239 if (rl_equiv(rl, estate_rl(state)))
1240 return;
1241 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1242 } else {
1243 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1244 }
1245 }
1246
1247 static void match_dereferences(struct expression *expr)
1248 {
1249 if (expr->type != EXPR_PREOP)
1250 return;
1251 /* it's saying that foo[1] = bar dereferences foo[1] */
1252 if (is_array(expr))
1253 return;
1254 check_dereference(expr->unop);
1255 }
1256
1257 static void match_pointer_as_array(struct expression *expr)
1258 {
1259 if (!is_array(expr))
1260 return;
1261 check_dereference(get_array_base(expr));
1262 }
1263
1264 static void find_dereferences(struct expression *expr)
1265 {
1266 while (expr->type == EXPR_PREOP) {
1267 if (expr->op == '*')
1268 check_dereference(expr->unop);
1269 expr = strip_expr(expr->unop);
1270 }
1271 }
1272
1273 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
1274 {
1275 struct symbol *sym;
1276 char *name;
1277
1278 name = get_variable_from_key(arg, key, &sym);
1279 if (name && sym) {
1280 struct smatch_state *orig, *new;
1281 struct range_list *rl;
1282
1283 orig = get_state(SMATCH_EXTRA, name, sym);
1284 if (orig) {
1285 rl = rl_intersection(estate_rl(orig),
1286 alloc_rl(valid_ptr_min_sval,
1287 valid_ptr_max_sval));
1288 new = alloc_estate_rl(rl);
1289 } else {
1290 new = alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval);
1291 }
1292
1293 set_extra_nomod(name, sym, NULL, new);
1294 }
1295 free_string(name);
1296
1297 find_dereferences(arg);
1298 }
1299
1300 static sval_t add_one(sval_t sval)
1301 {
1302 sval.value++;
1303 return sval;
1304 }
1305
1306 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1307 {
1308 struct statement *stmt;
1309 struct expression *cond;
1310 struct smatch_state *true_state, *false_state;
1311 sval_t start;
1312 sval_t limit;
1313
1314 /*
1315 * If we're decrementing here then that's a canonical while count down
1316 * so it's handled already. We're only handling loops like:
1317 * i = 0;
1318 * do { ... } while (i++ < 3);
1319 */
1320
1321 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1322 return 0;
1323
1324 stmt = __cur_stmt->parent;
1325 if (!stmt)
1326 return 0;
1327 if (stmt->type == STMT_COMPOUND)
1328 stmt = stmt->parent;
1329 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1330 return 0;
1331
1332 cond = strip_expr(stmt->iterator_post_condition);
1333 if (cond->type != EXPR_COMPARE || cond->op != op)
1334 return 0;
1335 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1336 return 0;
1337
1338 if (!get_implied_value(left->unop, &start))
1339 return 0;
1340 if (!get_implied_value(right, &limit))
1341 return 0;
1342
1343 if (sval_cmp(start, limit) > 0)
1344 return 0;
1345
1346 switch (op) {
1347 case '<':
1348 case SPECIAL_UNSIGNED_LT:
1349 break;
1350 case SPECIAL_LTE:
1351 case SPECIAL_UNSIGNED_LTE:
1352 limit = add_one(limit);
1353 default:
1354 return 0;
1355
1356 }
1357
1358 true_state = alloc_estate_range(add_one(start), limit);
1359 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1360
1361 /* Currently we just discard the false state but when two passes is
1362 * implimented correctly then it will use it.
1363 */
1364
1365 set_extra_expr_true_false(left->unop, true_state, false_state);
1366
1367 return 1;
1368 }
1369
1370 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1371 {
1372 struct range_list *left_orig;
1373 struct range_list *left_true;
1374 struct range_list *left_false;
1375 struct range_list *right_orig;
1376 struct range_list *right_true;
1377 struct range_list *right_false;
1378 struct smatch_state *left_true_state;
1379 struct smatch_state *left_false_state;
1380 struct smatch_state *right_true_state;
1381 struct smatch_state *right_false_state;
1382 sval_t dummy, hard_max;
1383 int left_postop = 0;
1384 int right_postop = 0;
1385
1386 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1387 if (left->type == EXPR_POSTOP) {
1388 left->smatch_flags |= Handled;
1389 left_postop = left->op;
1390 if (handle_postop_inc(left, op, right))
1391 return;
1392 }
1393 left = strip_parens(left->unop);
1394 }
1395 while (left->type == EXPR_ASSIGNMENT)
1396 left = strip_parens(left->left);
1397
1398 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1399 if (right->type == EXPR_POSTOP) {
1400 right->smatch_flags |= Handled;
1401 right_postop = right->op;
1402 }
1403 right = strip_parens(right->unop);
1404 }
1405
1406 get_real_absolute_rl(left, &left_orig);
1407 left_orig = cast_rl(type, left_orig);
1408
1409 get_real_absolute_rl(right, &right_orig);
1410 right_orig = cast_rl(type, right_orig);
1411
1412 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1413
1414 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1415 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1416 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1417 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1418
1419 if (!left_true || !left_false) {
1420 struct range_list *tmp_true, *tmp_false;
1421
1422 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1423 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1424 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1425 if (tmp_true && tmp_false)
1426 __save_imaginary_state(left, tmp_true, tmp_false);
1427 }
1428
1429 if (!right_true || !right_false) {
1430 struct range_list *tmp_true, *tmp_false;
1431
1432 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1433 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1434 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1435 if (tmp_true && tmp_false)
1436 __save_imaginary_state(right, tmp_true, tmp_false);
1437 }
1438
1439 left_true_state = alloc_estate_rl(left_true);
1440 left_false_state = alloc_estate_rl(left_false);
1441 right_true_state = alloc_estate_rl(right_true);
1442 right_false_state = alloc_estate_rl(right_false);
1443
1444 switch (op) {
1445 case '<':
1446 case SPECIAL_UNSIGNED_LT:
1447 case SPECIAL_UNSIGNED_LTE:
1448 case SPECIAL_LTE:
1449 if (get_hard_max(right, &dummy))
1450 estate_set_hard_max(left_true_state);
1451 if (get_hard_max(left, &dummy))
1452 estate_set_hard_max(right_false_state);
1453 break;
1454 case '>':
1455 case SPECIAL_UNSIGNED_GT:
1456 case SPECIAL_UNSIGNED_GTE:
1457 case SPECIAL_GTE:
1458 if (get_hard_max(left, &dummy))
1459 estate_set_hard_max(right_true_state);
1460 if (get_hard_max(right, &dummy))
1461 estate_set_hard_max(left_false_state);
1462 break;
1463 }
1464
1465 switch (op) {
1466 case '<':
1467 case SPECIAL_UNSIGNED_LT:
1468 case SPECIAL_UNSIGNED_LTE:
1469 case SPECIAL_LTE:
1470 if (get_hard_max(right, &hard_max)) {
1471 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1472 hard_max.value--;
1473 estate_set_fuzzy_max(left_true_state, hard_max);
1474 }
1475 if (get_implied_value(right, &hard_max)) {
1476 if (op == SPECIAL_UNSIGNED_LTE ||
1477 op == SPECIAL_LTE)
1478 hard_max.value++;
1479 estate_set_fuzzy_max(left_false_state, hard_max);
1480 }
1481 if (get_hard_max(left, &hard_max)) {
1482 if (op == SPECIAL_UNSIGNED_LTE ||
1483 op == SPECIAL_LTE)
1484 hard_max.value--;
1485 estate_set_fuzzy_max(right_false_state, hard_max);
1486 }
1487 if (get_implied_value(left, &hard_max)) {
1488 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1489 hard_max.value++;
1490 estate_set_fuzzy_max(right_true_state, hard_max);
1491 }
1492 break;
1493 case '>':
1494 case SPECIAL_UNSIGNED_GT:
1495 case SPECIAL_UNSIGNED_GTE:
1496 case SPECIAL_GTE:
1497 if (get_hard_max(left, &hard_max)) {
1498 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1499 hard_max.value--;
1500 estate_set_fuzzy_max(right_true_state, hard_max);
1501 }
1502 if (get_implied_value(left, &hard_max)) {
1503 if (op == SPECIAL_UNSIGNED_GTE ||
1504 op == SPECIAL_GTE)
1505 hard_max.value++;
1506 estate_set_fuzzy_max(right_false_state, hard_max);
1507 }
1508 if (get_hard_max(right, &hard_max)) {
1509 if (op == SPECIAL_UNSIGNED_LTE ||
1510 op == SPECIAL_LTE)
1511 hard_max.value--;
1512 estate_set_fuzzy_max(left_false_state, hard_max);
1513 }
1514 if (get_implied_value(right, &hard_max)) {
1515 if (op == '>' ||
1516 op == SPECIAL_UNSIGNED_GT)
1517 hard_max.value++;
1518 estate_set_fuzzy_max(left_true_state, hard_max);
1519 }
1520 break;
1521 case SPECIAL_EQUAL:
1522 if (get_hard_max(left, &hard_max))
1523 estate_set_fuzzy_max(right_true_state, hard_max);
1524 if (get_hard_max(right, &hard_max))
1525 estate_set_fuzzy_max(left_true_state, hard_max);
1526 break;
1527 }
1528
1529 if (get_hard_max(left, &hard_max)) {
1530 estate_set_hard_max(left_true_state);
1531 estate_set_hard_max(left_false_state);
1532 }
1533 if (get_hard_max(right, &hard_max)) {
1534 estate_set_hard_max(right_true_state);
1535 estate_set_hard_max(right_false_state);
1536 }
1537
1538 if (left_postop == SPECIAL_INCREMENT) {
1539 left_true_state = increment_state(left_true_state);
1540 left_false_state = increment_state(left_false_state);
1541 }
1542 if (left_postop == SPECIAL_DECREMENT) {
1543 left_true_state = decrement_state(left_true_state);
1544 left_false_state = decrement_state(left_false_state);
1545 }
1546 if (right_postop == SPECIAL_INCREMENT) {
1547 right_true_state = increment_state(right_true_state);
1548 right_false_state = increment_state(right_false_state);
1549 }
1550 if (right_postop == SPECIAL_DECREMENT) {
1551 right_true_state = decrement_state(right_true_state);
1552 right_false_state = decrement_state(right_false_state);
1553 }
1554
1555 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1556 left_true_state = NULL;
1557 left_false_state = NULL;
1558 }
1559
1560 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1561 right_true_state = NULL;
1562 right_false_state = NULL;
1563 }
1564
1565 /* Don't introduce new states for known true/false conditions */
1566 if (rl_equiv(left_orig, estate_rl(left_true_state)))
1567 left_true_state = NULL;
1568 if (rl_equiv(left_orig, estate_rl(left_false_state)))
1569 left_false_state = NULL;
1570 if (rl_equiv(right_orig, estate_rl(right_true_state)))
1571 right_true_state = NULL;
1572 if (rl_equiv(right_orig, estate_rl(right_false_state)))
1573 right_false_state = NULL;
1574
1575 set_extra_expr_true_false(left, left_true_state, left_false_state);
1576 set_extra_expr_true_false(right, right_true_state, right_false_state);
1577 }
1578
1579 static int is_simple_math(struct expression *expr)
1580 {
1581 if (!expr)
1582 return 0;
1583 if (expr->type != EXPR_BINOP)
1584 return 0;
1585 switch (expr->op) {
1586 case '+':
1587 case '-':
1588 case '*':
1589 return 1;
1590 }
1591 return 0;
1592 }
1593
1594 static void move_known_values(struct expression **left_p, struct expression **right_p)
1595 {
1596 struct expression *left = *left_p;
1597 struct expression *right = *right_p;
1598 sval_t sval, dummy;
1599
1600 if (get_implied_value(left, &sval)) {
1601 if (!is_simple_math(right))
1602 return;
1603 if (get_implied_value(right, &dummy))
1604 return;
1605 if (right->op == '*') {
1606 sval_t divisor;
1607
1608 if (!get_value(right->right, &divisor))
1609 return;
1610 if (divisor.value == 0 && sval.value % divisor.value)
1611 return;
1612 *left_p = binop_expression(left, invert_op(right->op), right->right);
1613 *right_p = right->left;
1614 return;
1615 }
1616 if (right->op == '+' && get_value(right->left, &sval)) {
1617 *left_p = binop_expression(left, invert_op(right->op), right->left);
1618 *right_p = right->right;
1619 return;
1620 }
1621 if (get_value(right->right, &sval)) {
1622 *left_p = binop_expression(left, invert_op(right->op), right->right);
1623 *right_p = right->left;
1624 return;
1625 }
1626 return;
1627 }
1628 if (get_implied_value(right, &sval)) {
1629 if (!is_simple_math(left))
1630 return;
1631 if (get_implied_value(left, &dummy))
1632 return;
1633 if (left->op == '*') {
1634 sval_t divisor;
1635
1636 if (!get_value(left->right, &divisor))
1637 return;
1638 if (divisor.value == 0 && sval.value % divisor.value)
1639 return;
1640 *right_p = binop_expression(right, invert_op(left->op), left->right);
1641 *left_p = left->left;
1642 return;
1643 }
1644 if (left->op == '+' && get_value(left->left, &sval)) {
1645 *right_p = binop_expression(right, invert_op(left->op), left->left);
1646 *left_p = left->right;
1647 return;
1648 }
1649
1650 if (get_value(left->right, &sval)) {
1651 *right_p = binop_expression(right, invert_op(left->op), left->right);
1652 *left_p = left->left;
1653 return;
1654 }
1655 return;
1656 }
1657 }
1658
1659 /*
1660 * The reason for do_simple_algebra() is to solve things like:
1661 * if (foo > 66 || foo + bar > 64) {
1662 * "foo" is not really a known variable so it won't be handled by
1663 * move_known_variables() but it's a super common idiom.
1664 *
1665 */
1666 static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
1667 {
1668 struct expression *left = *left_p;
1669 struct expression *right = *right_p;
1670 struct range_list *rl;
1671 sval_t tmp;
1672
1673 if (left->type != EXPR_BINOP || left->op != '+')
1674 return 0;
1675 if (can_integer_overflow(get_type(left), left))
1676 return 0;
1677 if (!get_implied_value(right, &tmp))
1678 return 0;
1679
1680 if (!get_implied_value(left->left, &tmp) &&
1681 get_implied_rl(left->left, &rl) &&
1682 !is_whole_rl(rl)) {
1683 *right_p = binop_expression(right, '-', left->left);
1684 *left_p = left->right;
1685 return 1;
1686 }
1687 if (!get_implied_value(left->right, &tmp) &&
1688 get_implied_rl(left->right, &rl) &&
1689 !is_whole_rl(rl)) {
1690 *right_p = binop_expression(right, '-', left->right);
1691 *left_p = left->left;
1692 return 1;
1693 }
1694
1695 return 0;
1696 }
1697
1698 static int match_func_comparison(struct expression *expr)
1699 {
1700 struct expression *left = strip_expr(expr->left);
1701 struct expression *right = strip_expr(expr->right);
1702 sval_t sval;
1703
1704 /*
1705 * fixme: think about this harder. We should always be trying to limit
1706 * the non-call side as well. If we can't determine the limitter does
1707 * that mean we aren't querying the database and are missing important
1708 * information?
1709 */
1710
1711 if (left->type == EXPR_CALL) {
1712 if (get_implied_value(left, &sval)) {
1713 handle_comparison(get_type(expr), left, expr->op, right);
1714 return 1;
1715 }
1716 function_comparison(left, expr->op, right);
1717 return 1;
1718 }
1719
1720 if (right->type == EXPR_CALL) {
1721 if (get_implied_value(right, &sval)) {
1722 handle_comparison(get_type(expr), left, expr->op, right);
1723 return 1;
1724 }
1725 function_comparison(left, expr->op, right);
1726 return 1;
1727 }
1728
1729 return 0;
1730 }
1731
1732 /* Handle conditions like "if (foo + bar < foo) {" */
1733 static int handle_integer_overflow_test(struct expression *expr)
1734 {
1735 struct expression *left, *right;
1736 struct symbol *type;
1737 sval_t left_min, right_min, min, max;
1738
1739 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
1740 return 0;
1741
1742 left = strip_parens(expr->left);
1743 right = strip_parens(expr->right);
1744
1745 if (left->op != '+')
1746 return 0;
1747
1748 type = get_type(expr);
1749 if (!type)
1750 return 0;
1751 if (type_positive_bits(type) == 32) {
1752 max.type = &uint_ctype;
1753 max.uvalue = (unsigned int)-1;
1754 } else if (type_positive_bits(type) == 64) {
1755 max.type = &ulong_ctype;
1756 max.value = (unsigned long long)-1;
1757 } else {
1758 return 0;
1759 }
1760
1761 if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
1762 return 0;
1763
1764 get_absolute_min(left->left, &left_min);
1765 get_absolute_min(left->right, &right_min);
1766 min = sval_binop(left_min, '+', right_min);
1767
1768 set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
1769 return 1;
1770 }
1771
1772 static void match_comparison(struct expression *expr)
1773 {
1774 struct expression *left_orig = strip_parens(expr->left);
1775 struct expression *right_orig = strip_parens(expr->right);
1776 struct expression *left, *right, *tmp;
1777 struct expression *prev;
1778 struct symbol *type;
1779 int redo, count;
1780
1781 if (match_func_comparison(expr))
1782 return;
1783
1784 type = get_type(expr);
1785 if (!type)
1786 type = &llong_ctype;
1787
1788 if (handle_integer_overflow_test(expr))
1789 return;
1790
1791 left = left_orig;
1792 right = right_orig;
1793 move_known_values(&left, &right);
1794 handle_comparison(type, left, expr->op, right);
1795
1796 left = left_orig;
1797 right = right_orig;
1798 if (do_simple_algebra(&left, &right))
1799 handle_comparison(type, left, expr->op, right);
1800
1801 prev = get_assigned_expr(left_orig);
1802 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1803 left = prev;
1804 right = right_orig;
1805 move_known_values(&left, &right);
1806 handle_comparison(type, left, expr->op, right);
1807 }
1808
1809 prev = get_assigned_expr(right_orig);
1810 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1811 left = left_orig;
1812 right = prev;
1813 move_known_values(&left, &right);
1814 handle_comparison(type, left, expr->op, right);
1815 }
1816
1817 redo = 0;
1818 left = left_orig;
1819 right = right_orig;
1820 if (get_last_expr_from_expression_stmt(left_orig)) {
1821 left = get_last_expr_from_expression_stmt(left_orig);
1822 redo = 1;
1823 }
1824 if (get_last_expr_from_expression_stmt(right_orig)) {
1825 right = get_last_expr_from_expression_stmt(right_orig);
1826 redo = 1;
1827 }
1828
1829 if (!redo)
1830 return;
1831
1832 count = 0;
1833 while ((tmp = get_assigned_expr(left))) {
1834 if (count++ > 3)
1835 break;
1836 left = strip_expr(tmp);
1837 }
1838 count = 0;
1839 while ((tmp = get_assigned_expr(right))) {
1840 if (count++ > 3)
1841 break;
1842 right = strip_expr(tmp);
1843 }
1844
1845 handle_comparison(type, left, expr->op, right);
1846 }
1847
1848 static sval_t get_high_mask(sval_t known)
1849 {
1850 sval_t ret;
1851 int i;
1852
1853 ret = known;
1854 ret.value = 0;
1855
1856 for (i = type_bits(known.type) - 1; i >= 0; i--) {
1857 if (known.uvalue & (1ULL << i))
1858 ret.uvalue |= (1ULL << i);
1859 else
1860 return ret;
1861
1862 }
1863 return ret;
1864 }
1865
1866 static void handle_AND_op(struct expression *var, sval_t known)
1867 {
1868 struct range_list *orig_rl;
1869 struct range_list *true_rl = NULL;
1870 struct range_list *false_rl = NULL;
1871 int bit;
1872 sval_t low_mask = known;
1873 sval_t high_mask;
1874 sval_t max;
1875
1876 get_absolute_rl(var, &orig_rl);
1877
1878 if (known.value > 0) {
1879 bit = ffsll(known.value) - 1;
1880 low_mask.uvalue = (1ULL << bit) - 1;
1881 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
1882 }
1883 high_mask = get_high_mask(known);
1884 if (high_mask.value) {
1885 bit = ffsll(high_mask.value) - 1;
1886 low_mask.uvalue = (1ULL << bit) - 1;
1887
1888 false_rl = orig_rl;
1889 if (sval_is_negative(rl_min(orig_rl)))
1890 false_rl = remove_range(false_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
1891 false_rl = remove_range(false_rl, low_mask, sval_type_max(known.type));
1892 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
1893 false_rl = remove_range(false_rl,
1894 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
1895 sval_type_val(rl_type(false_rl), -1));
1896 }
1897 } else if (known.value == 1 &&
1898 get_hard_max(var, &max) &&
1899 sval_cmp(max, rl_max(orig_rl)) == 0 &&
1900 max.value & 1) {
1901 false_rl = remove_range(orig_rl, max, max);
1902 }
1903 set_extra_expr_true_false(var,
1904 true_rl ? alloc_estate_rl(true_rl) : NULL,
1905 false_rl ? alloc_estate_rl(false_rl) : NULL);
1906 }
1907
1908 static void handle_AND_condition(struct expression *expr)
1909 {
1910 sval_t known;
1911
1912 if (get_implied_value(expr->left, &known))
1913 handle_AND_op(expr->right, known);
1914 else if (get_implied_value(expr->right, &known))
1915 handle_AND_op(expr->left, known);
1916 }
1917
1918 static void handle_MOD_condition(struct expression *expr)
1919 {
1920 struct range_list *orig_rl;
1921 struct range_list *true_rl;
1922 struct range_list *false_rl = NULL;
1923 sval_t right;
1924 sval_t zero = {
1925 .value = 0,
1926 };
1927
1928 if (!get_implied_value(expr->right, &right) || right.value == 0)
1929 return;
1930 get_absolute_rl(expr->left, &orig_rl);
1931
1932 zero.type = rl_type(orig_rl);
1933
1934 /* We're basically dorking around the min and max here */
1935 true_rl = remove_range(orig_rl, zero, zero);
1936 if (!sval_is_max(rl_max(true_rl)) &&
1937 !(rl_max(true_rl).value % right.value))
1938 true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));
1939
1940 if (rl_equiv(true_rl, orig_rl))
1941 true_rl = NULL;
1942
1943 if (sval_is_positive(rl_min(orig_rl)) &&
1944 (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
1945 sval_t add;
1946 int i;
1947
1948 add = rl_min(orig_rl);
1949 add.value += right.value - (add.value % right.value);
1950 add.value -= right.value;
1951
1952 for (i = 0; i < 5; i++) {
1953 add.value += right.value;
1954 if (add.value > rl_max(orig_rl).value)
1955 break;
1956 add_range(&false_rl, add, add);
1957 }
1958 } else {
1959 if (rl_min(orig_rl).uvalue != 0 &&
1960 rl_min(orig_rl).uvalue < right.uvalue) {
1961 sval_t chop = right;
1962 chop.value--;
1963 false_rl = remove_range(orig_rl, zero, chop);
1964 }
1965
1966 if (!sval_is_max(rl_max(orig_rl)) &&
1967 (rl_max(orig_rl).value % right.value)) {
1968 sval_t chop = rl_max(orig_rl);
1969 chop.value -= chop.value % right.value;
1970 chop.value++;
1971 if (!false_rl)
1972 false_rl = clone_rl(orig_rl);
1973 false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
1974 }
1975 }
1976
1977 set_extra_expr_true_false(expr->left,
1978 true_rl ? alloc_estate_rl(true_rl) : NULL,
1979 false_rl ? alloc_estate_rl(false_rl) : NULL);
1980 }
1981
1982 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1983 void __extra_match_condition(struct expression *expr)
1984 {
1985 struct smatch_state *pre_state;
1986 struct smatch_state *true_state;
1987 struct smatch_state *false_state;
1988 struct range_list *pre_rl;
1989
1990 expr = strip_expr(expr);
1991 switch (expr->type) {
1992 case EXPR_CALL:
1993 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1994 return;
1995 case EXPR_PREOP:
1996 case EXPR_SYMBOL:
1997 case EXPR_DEREF: {
1998 sval_t zero;
1999
2000 zero = sval_blank(expr);
2001 zero.value = 0;
2002
2003 pre_state = get_extra_state(expr);
2004 if (estate_is_empty(pre_state))
2005 return;
2006 if (pre_state)
2007 pre_rl = estate_rl(pre_state);
2008 else
2009 get_absolute_rl(expr, &pre_rl);
2010 if (possibly_true_rl(pre_rl, SPECIAL_EQUAL, rl_zero()))
2011 false_state = alloc_estate_sval(zero);
2012 else
2013 false_state = alloc_estate_empty();
2014 true_state = alloc_estate_rl(remove_range(pre_rl, zero, zero));
2015 set_extra_expr_true_false(expr, true_state, false_state);
2016 return;
2017 }
2018 case EXPR_COMPARE:
2019 match_comparison(expr);
2020 return;
2021 case EXPR_ASSIGNMENT:
2022 __extra_match_condition(expr->left);
2023 return;
2024 case EXPR_BINOP:
2025 if (expr->op == '&')
2026 handle_AND_condition(expr);
2027 if (expr->op == '%')
2028 handle_MOD_condition(expr);
2029 return;
2030 }
2031 }
2032
2033 static void assume_indexes_are_valid(struct expression *expr)
2034 {
2035 struct expression *array_expr;
2036 int array_size;
2037 struct expression *offset;
2038 struct symbol *offset_type;
2039 struct range_list *rl_before;
2040 struct range_list *rl_after;
2041 struct range_list *filter = NULL;
2042 sval_t size;
2043
2044 expr = strip_expr(expr);
2045 if (!is_array(expr))
2046 return;
2047
2048 offset = get_array_offset(expr);
2049 offset_type = get_type(offset);
2050 if (offset_type && type_signed(offset_type)) {
2051 filter = alloc_rl(sval_type_min(offset_type),
2052 sval_type_val(offset_type, -1));
2053 }
2054
2055 array_expr = get_array_base(expr);
2056 array_size = get_real_array_size(array_expr);
2057 if (array_size > 1) {
2058 size = sval_type_val(offset_type, array_size);
2059 add_range(&filter, size, sval_type_max(offset_type));
2060 }
2061
2062 if (!filter)
2063 return;
2064 get_absolute_rl(offset, &rl_before);
2065 rl_after = rl_filter(rl_before, filter);
2066 if (rl_equiv(rl_before, rl_after))
2067 return;
2068 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
2069 }
2070
2071 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
2072 int implied_not_equal(struct expression *expr, long long val)
2073 {
2074 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
2075 }
2076
2077 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
2078 {
2079 struct smatch_state *estate;
2080
2081 estate = get_state(SMATCH_EXTRA, name, sym);
2082 if (!estate)
2083 return 0;
2084 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
2085 return 1;
2086 return 0;
2087 }
2088
2089 int parent_is_null_var_sym(const char *name, struct symbol *sym)
2090 {
2091 char buf[256];
2092 char *start;
2093 char *end;
2094 struct smatch_state *state;
2095
2096 strncpy(buf, name, sizeof(buf) - 1);
2097 buf[sizeof(buf) - 1] = '\0';
2098
2099 start = &buf[0];
2100 while (*start == '*') {
2101 start++;
2102 state = get_state(SMATCH_EXTRA, start, sym);
2103 if (!state)
2104 continue;
2105 if (!estate_rl(state))
2106 return 1;
2107 if (estate_min(state).value == 0 &&
2108 estate_max(state).value == 0)
2109 return 1;
2110 }
2111
2112 start = &buf[0];
2113 while (*start == '&')
2114 start++;
2115
2116 while ((end = strrchr(start, '-'))) {
2117 *end = '\0';
2118 state = __get_state(SMATCH_EXTRA, start, sym);
2119 if (!state)
2120 continue;
2121 if (estate_min(state).value == 0 &&
2122 estate_max(state).value == 0)
2123 return 1;
2124 }
2125 return 0;
2126 }
2127
2128 int parent_is_null(struct expression *expr)
2129 {
2130 struct symbol *sym;
2131 char *var;
2132 int ret = 0;
2133
2134 expr = strip_expr(expr);
2135 var = expr_to_var_sym(expr, &sym);
2136 if (!var || !sym)
2137 goto free;
2138 ret = parent_is_null_var_sym(var, sym);
2139 free:
2140 free_string(var);
2141 return ret;
2142 }
2143
2144 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
2145 {
2146 *(int *)found = 1;
2147 return 0;
2148 }
2149
2150 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2151 {
2152 sval_t sval;
2153 int found = 0;
2154
2155 /* for function pointers assume everything is used */
2156 if (call->fn->type != EXPR_SYMBOL)
2157 return 0;
2158
2159 /*
2160 * kzalloc() information is treated as special because so there is just
2161 * a lot of stuff initialized to zero and it makes building the database
2162 * take hours and hours.
2163 *
2164 * In theory, we should just remove this line and not pass any unused
2165 * information, but I'm not sure enough that this code works so I want
2166 * to hold off on that for now.
2167 */
2168 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
2169 return 0;
2170
2171 run_sql(&param_used_callback, &found,
2172 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
2173 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
2174 if (found)
2175 return 0;
2176
2177 /* If the database is not built yet, then assume everything is used */
2178 run_sql(&param_used_callback, &found,
2179 "select * from call_implies where %s and type = %d;",
2180 get_static_filter(call->fn->symbol), PARAM_USED);
2181 if (!found)
2182 return 0;
2183
2184 return 1;
2185 }
2186
2187 struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
2188 {
2189 struct smatch_state *state;
2190
2191 /*
2192 * Here is the difference between implied value and real absolute, say
2193 * you have:
2194 *
2195 * int a = (u8)x;
2196 *
2197 * Then you know that a is 0-255. That's real absolute. But you don't
2198 * know for sure that it actually goes up to 255. So it's not implied.
2199 * Implied indicates a degree of certainty.
2200 *
2201 * But then say you cap "a" at 8. That means you know it goes up to
2202 * 8. So now the implied value is s32min-8. But you can combine it
2203 * with the real absolute to say that actually it's 0-8.
2204 *
2205 * We are combining it here. But now that I think about it, this is
2206 * probably not the ideal place to combine it because it should proably
2207 * be done earlier. Oh well, this is an improvement on what was there
2208 * before so I'm going to commit this code.
2209 *
2210 */
2211
2212 state = get_real_absolute_state_var_sym(name, sym);
2213 if (!state || !estate_rl(state))
2214 return start;
2215
2216 return rl_intersection(estate_rl(state), start);
2217 }
2218
2219 struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
2220 {
2221 struct smatch_state *state;
2222
2223 state = get_real_absolute_state(expr);
2224 if (!state || !estate_rl(state))
2225 return start;
2226
2227 return rl_intersection(estate_rl(state), start);
2228 }
2229
2230 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2231 {
2232 struct range_list *rl;
2233
2234 if (estate_is_whole(sm->state))
2235 return;
2236 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
2237 return;
2238 rl = estate_rl(sm->state);
2239 rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
2240 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
2241 if (estate_has_fuzzy_max(sm->state))
2242 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
2243 sval_to_str(estate_get_fuzzy_max(sm->state)));
2244 }
2245
2246 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
2247 {
2248 struct symbol *returned_sym;
2249 struct sm_state *sm;
2250 const char *param_name;
2251 char *compare_str;
2252 char buf[256];
2253
2254 returned_sym = expr_to_sym(expr);
2255 if (!returned_sym)
2256 return;
2257
2258 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
2259 if (!estate_rl(sm->state))
2260 continue;
2261 if (returned_sym != sm->sym)
2262 continue;
2263
2264 param_name = get_param_name(sm);
2265 if (!param_name)
2266 continue;
2267 if (strcmp(param_name, "$") == 0)
2268 continue;
2269 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
2270 if (!compare_str && estate_is_whole(sm->state))
2271 continue;
2272 snprintf(buf, sizeof(buf), "%s%s", sm->state->name, compare_str ?: "");
2273
2274 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
2275 -1, param_name, buf);
2276 } END_FOR_EACH_SM(sm);
2277 }
2278
2279 static void db_limited_before(void)
2280 {
2281 unmatched_stree = clone_stree(__get_cur_stree());
2282 }
2283
2284 static void db_limited_after(void)
2285 {
2286 free_stree(&unmatched_stree);
2287 }
2288
2289 static int rl_fits_in_type(struct range_list *rl, struct symbol *type)
2290 {
2291 if (type_bits(rl_type(rl)) <= type_bits(type))
2292 return 1;
2293 if (sval_cmp(rl_max(rl), sval_type_max(type)) > 0)
2294 return 0;
2295 if (sval_is_negative(rl_min(rl)) &&
2296 sval_cmp(rl_min(rl), sval_type_min(type)) < 0)
2297 return 0;
2298 return 1;
2299 }
2300
2301 static int basically_the_same(struct range_list *orig, struct range_list *new)
2302 {
2303 if (rl_equiv(orig, new))
2304 return 1;
2305
2306 /*
2307 * The whole range is essentially the same as 0,4096-27777777777 so
2308 * don't overwrite the implications just to store that.
2309 *
2310 */
2311 if (rl_type(orig)->type == SYM_PTR &&
2312 is_whole_rl(orig) &&
2313 rl_min(new).value == 0 &&
2314 rl_max(new).value == valid_ptr_max)
2315 return 1;
2316 return 0;
2317 }
2318
2319 static void db_param_limit_binops(struct expression *arg, char *key, struct range_list *rl)
2320 {
2321 struct range_list *left_rl;
2322 sval_t zero = { .type = rl_type(rl), };
2323 sval_t sval;
2324
2325 if (arg->op != '*')
2326 return;
2327 if (!get_implied_value(arg->right, &sval))
2328 return;
2329 if (can_integer_overflow(get_type(arg), arg))
2330 return;
2331
2332 left_rl = rl_binop(rl, '/', alloc_rl(sval, sval));
2333 if (!rl_has_sval(rl, zero))
2334 left_rl = remove_range(left_rl, zero, zero);
2335
2336 set_extra_expr_nomod(arg->left, alloc_estate_rl(left_rl));
2337 }
2338
2339 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
2340 {
2341 struct expression *arg;
2342 char *name;
2343 struct symbol *sym;
2344 struct var_sym_list *vsl = NULL;
2345 struct sm_state *sm;
2346 struct symbol *compare_type, *var_type;
2347 struct range_list *rl;
2348 struct range_list *limit;
2349 struct range_list *new;
2350 char *tmp_name;
2351 struct symbol *tmp_sym;
2352
2353 while (expr->type == EXPR_ASSIGNMENT)
2354 expr = strip_expr(expr->right);
2355 if (expr->type != EXPR_CALL)
2356 return;
2357
2358 arg = get_argument_from_call_expr(expr->args, param);
2359 if (!arg)
2360 return;
2361
2362 name = get_chunk_from_key(arg, key, &sym, &vsl);
2363 if (!name)
2364 return;
2365 if (op != PARAM_LIMIT && !sym)
2366 goto free;
2367
2368 if (strcmp(key, "$") == 0)
2369 compare_type = get_arg_type(expr->fn, param);
2370 else
2371 compare_type = get_member_type_from_key(arg, key);
2372
2373 sm = get_sm_state(SMATCH_EXTRA, name, sym);
2374 if (sm)
2375 rl = estate_rl(sm->state);
2376 else
2377 rl = alloc_whole_rl(compare_type);
2378
2379 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
2380 goto free;
2381
2382 call_results_to_rl(expr, compare_type, value, &limit);
2383 new = rl_intersection(rl, limit);
2384
2385 var_type = get_member_type_from_key(arg, key);
2386 new = cast_rl(var_type, new);
2387
2388 /* We want to preserve the implications here */
2389 if (sm && basically_the_same(estate_rl(sm->state), new))
2390 goto free;
2391 tmp_name = map_long_to_short_name_sym(name, sym, &tmp_sym);
2392 if (tmp_name && tmp_sym) {
2393 free_string(name);
2394 name = tmp_name;
2395 sym = tmp_sym;
2396 }
2397
2398 if (op == PARAM_LIMIT)
2399 set_extra_nomod_vsl(name, sym, vsl, NULL, alloc_estate_rl(new));
2400 else
2401 set_extra_mod(name, sym, NULL, alloc_estate_rl(new));
2402
2403 if (op == PARAM_LIMIT && arg->type == EXPR_BINOP)
2404 db_param_limit_binops(arg, key, new);
2405 free:
2406 free_string(name);
2407 }
2408
2409 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
2410 {
2411 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
2412 }
2413
2414 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
2415 {
2416 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
2417 }
2418
2419 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
2420 {
2421 struct expression *arg;
2422 char *name, *tmp_name;
2423 struct symbol *sym, *tmp_sym;
2424 struct symbol *type;
2425 struct smatch_state *state;
2426 struct range_list *new = NULL;
2427 struct range_list *added = NULL;
2428
2429 while (expr->type == EXPR_ASSIGNMENT)
2430 expr = strip_expr(expr->right);
2431 if (expr->type != EXPR_CALL)
2432 return;
2433
2434 arg = get_argument_from_call_expr(expr->args, param);
2435 if (!arg)
2436 return;
2437 type = get_member_type_from_key(arg, key);
2438 name = get_variable_from_key(arg, key, &sym);
2439 if (!name || !sym)
2440 goto free;
2441
2442 state = get_state(SMATCH_EXTRA, name, sym);
2443 if (state)
2444 new = estate_rl(state);
2445
2446 call_results_to_rl(expr, type, value, &added);
2447
2448 if (op == PARAM_SET)
2449 new = added;
2450 else
2451 new = rl_union(new, added);
2452
2453 tmp_name = map_long_to_short_name_sym_nostack(name, sym, &tmp_sym);
2454 if (tmp_name && tmp_sym) {
2455 free_string(name);
2456 name = tmp_name;
2457 sym = tmp_sym;
2458 }
2459 set_extra_mod(name, sym, NULL, alloc_estate_rl(new));
2460 free:
2461 free_string(name);
2462 }
2463
2464 static void db_param_add(struct expression *expr, int param, char *key, char *value)
2465 {
2466 in_param_set = true;
2467 db_param_add_set(expr, param, key, value, PARAM_ADD);
2468 in_param_set = false;
2469 }
2470
2471 static void db_param_set(struct expression *expr, int param, char *key, char *value)
2472 {
2473 in_param_set = true;
2474 db_param_add_set(expr, param, key, value, PARAM_SET);
2475 in_param_set = false;
2476 }
2477
2478 static void db_param_value(struct expression *expr, int param, char *key, char *value)
2479 {
2480 struct expression *call;
2481 char *name;
2482 struct symbol *sym;
2483 struct symbol *type;
2484 struct range_list *rl = NULL;
2485
2486 if (param != -1)
2487 return;
2488
2489 call = expr;
2490 while (call->type == EXPR_ASSIGNMENT)
2491 call = strip_expr(call->right);
2492 if (call->type != EXPR_CALL)
2493 return;
2494
2495 type = get_member_type_from_key(expr->left, key);
2496 name = get_variable_from_key(expr->left, key, &sym);
2497 if (!name || !sym)
2498 goto free;
2499
2500 call_results_to_rl(call, type, value, &rl);
2501
2502 set_extra_mod(name, sym, NULL, alloc_estate_rl(rl));
2503 free:
2504 free_string(name);
2505 }
2506
2507 static void match_call_info(struct expression *expr)
2508 {
2509 struct smatch_state *state;
2510 struct range_list *rl = NULL;
2511 struct expression *arg;
2512 struct symbol *type;
2513 int i = 0;
2514
2515 FOR_EACH_PTR(expr->args, arg) {
2516 type = get_arg_type(expr->fn, i);
2517
2518 get_absolute_rl(arg, &rl);
2519 rl = cast_rl(type, rl);
2520
2521 if (!is_whole_rl(rl)) {
2522 rl = intersect_with_real_abs_expr(arg, rl);
2523 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
2524 }
2525 state = get_state_expr(SMATCH_EXTRA, arg);
2526 if (estate_has_fuzzy_max(state)) {
2527 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
2528 sval_to_str(estate_get_fuzzy_max(state)));
2529 }
2530 i++;
2531 } END_FOR_EACH_PTR(arg);
2532 }
2533
2534 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2535 {
2536 struct range_list *rl = NULL;
2537 struct smatch_state *state;
2538 struct symbol *type;
2539 char fullname[256];
2540 sval_t dummy;
2541
2542 if (strcmp(key, "*$") == 0)
2543 snprintf(fullname, sizeof(fullname), "*%s", name);
2544 else if (strncmp(key, "$", 1) == 0)
2545 snprintf(fullname, 256, "%s%s", name, key + 1);
2546 else
2547 return;
2548
2549 type = get_member_type_from_key(symbol_expression(sym), key);
2550 str_to_rl(type, value, &rl);
2551 state = alloc_estate_rl(rl);
2552 if (estate_get_single_value(state, &dummy))
2553 estate_set_hard_max(state);
2554 set_state(SMATCH_EXTRA, fullname, sym, state);
2555 }
2556
2557 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2558 {
2559 struct range_list *rl = NULL;
2560 struct smatch_state *state;
2561 struct symbol *type;
2562 char fullname[256];
2563 sval_t max;
2564
2565 if (strcmp(key, "*$") == 0)
2566 snprintf(fullname, sizeof(fullname), "*%s", name);
2567 else if (strncmp(key, "$", 1) == 0)
2568 snprintf(fullname, 256, "%s%s", name, key + 1);
2569 else
2570 return;
2571
2572 state = get_state(SMATCH_EXTRA, fullname, sym);
2573 if (!state)
2574 return;
2575 type = get_member_type_from_key(symbol_expression(sym), key);
2576 str_to_rl(type, value, &rl);
2577 if (!rl_to_sval(rl, &max))
2578 return;
2579 estate_set_fuzzy_max(state, max);
2580 }
2581
2582 struct smatch_state *get_extra_state(struct expression *expr)
2583 {
2584 char *name;
2585 struct symbol *sym;
2586 struct smatch_state *ret = NULL;
2587 struct range_list *rl;
2588
2589 if (is_pointer(expr) && get_address_rl(expr, &rl))
2590 return alloc_estate_rl(rl);
2591
2592 name = expr_to_known_chunk_sym(expr, &sym);
2593 if (!name)
2594 goto free;
2595
2596 ret = get_state(SMATCH_EXTRA, name, sym);
2597 free:
2598 free_string(name);
2599 return ret;
2600 }
2601
2602 void register_smatch_extra(int id)
2603 {
2604 my_id = id;
2605
2606 add_merge_hook(my_id, &merge_estates);
2607 add_unmatched_state_hook(my_id, &unmatched_state);
2608 select_caller_info_hook(set_param_value, PARAM_VALUE);
2609 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
2610 select_return_states_before(&db_limited_before);
2611 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2612 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2613 select_return_states_hook(PARAM_ADD, &db_param_add);
2614 select_return_states_hook(PARAM_SET, &db_param_set);
2615 select_return_states_hook(PARAM_VALUE, &db_param_value);
2616 select_return_states_after(&db_limited_after);
2617 }
2618
2619 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2620 {
2621 struct var_sym_list *links;
2622 struct var_sym *tmp;
2623 struct smatch_state *state;
2624
2625 links = sm->state->data;
2626
2627 FOR_EACH_PTR(links, tmp) {
2628 if (sm->sym == tmp->sym &&
2629 strcmp(sm->name, tmp->var) == 0)
2630 continue;
2631 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2632 if (!state)
2633 continue;
2634 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2635 } END_FOR_EACH_PTR(tmp);
2636 set_state(link_id, sm->name, sm->sym, &undefined);
2637 }
2638
2639 void register_smatch_extra_links(int id)
2640 {
2641 link_id = id;
2642 }
2643
2644 void register_smatch_extra_late(int id)
2645 {
2646 add_merge_hook(link_id, &merge_link_states);
2647 add_modification_hook(link_id, &match_link_modify);
2648 add_hook(&match_dereferences, DEREF_HOOK);
2649 add_hook(&match_pointer_as_array, OP_HOOK);
2650 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
2651 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2652 add_hook(&match_assign, ASSIGNMENT_HOOK);
2653 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2654 add_hook(&unop_expr, OP_HOOK);
2655 add_hook(&asm_expr, ASM_HOOK);
2656
2657 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
2658 add_member_info_callback(my_id, struct_member_callback);
2659 add_split_return_callback(&returned_struct_members);
2660
2661 add_hook(&assume_indexes_are_valid, OP_HOOK);
2662 }
Static analysis for C