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modification_hooks: handle PARAM_SET earlier
[smatch.git] / smatch_extra.c
blobf8b2328fb997196b768370b2719fcb2c2e984aa7
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_vanilla_assign(struct expression *left, struct expression *right)
793 {
794 struct range_list *orig_rl = NULL;
795 struct range_list *rl = NULL;
796 struct symbol *right_sym;
797 struct symbol *left_type;
798 struct symbol *right_type;
799 char *right_name = NULL;
800 struct symbol *sym;
801 char *name;
802 sval_t max;
803 struct smatch_state *state;
804 int comparison;
805
806 if (is_struct(left))
807 return;
808
809 save_chunk_info(left, right);
810
811 name = expr_to_var_sym(left, &sym);
812 if (!name) {
813 if (is_array(left))
814 do_array_assign(left, '=', right);
815 return;
816 }
817
818 left_type = get_type(left);
819 right_type = get_type(right);
820
821 right_name = expr_to_var_sym(right, &right_sym);
822
823 if (!__in_fake_assign &&
824 !(right->type == EXPR_PREOP && right->op == '&') &&
825 right_name && right_sym &&
826 values_fit_type(left, right) &&
827 !has_symbol(right, sym)) {
828 set_equiv(left, right);
829 goto free;
830 }
831
832 if (is_pointer(right) && get_address_rl(right, &rl)) {
833 state = alloc_estate_rl(rl);
834 goto done;
835 }
836
837 if (__in_fake_assign) {
838 struct smatch_state *right_state;
839 sval_t sval;
840
841 if (get_value(right, &sval)) {
842 sval = sval_cast(left_type, sval);
843 state = alloc_estate_sval(sval);
844 goto done;
845 }
846
847 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
848 if (right_state) {
849 /* simple assignment */
850 state = clone_estate(right_state);
851 goto done;
852 }
853
854 state = alloc_estate_rl(alloc_whole_rl(left_type));
855 goto done;
856 }
857
858 comparison = get_comparison(left, right);
859 if (comparison) {
860 comparison = flip_comparison(comparison);
861 get_implied_rl(left, &orig_rl);
862 }
863
864 if (get_implied_rl(right, &rl)) {
865 rl = cast_rl(left_type, rl);
866 if (orig_rl)
867 filter_by_comparison(&rl, comparison, orig_rl);
868 state = alloc_estate_rl(rl);
869 if (get_hard_max(right, &max)) {
870 estate_set_hard_max(state);
871 estate_set_fuzzy_max(state, max);
872 }
873 } else {
874 rl = alloc_whole_rl(right_type);
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 }
880
881 done:
882 set_extra_mod(name, sym, state);
883 free:
884 free_string(right_name);
885 }
886
887 static int op_remove_assign(int op)
888 {
889 switch (op) {
890 case SPECIAL_ADD_ASSIGN:
891 return '+';
892 case SPECIAL_SUB_ASSIGN:
893 return '-';
894 case SPECIAL_MUL_ASSIGN:
895 return '*';
896 case SPECIAL_DIV_ASSIGN:
897 return '/';
898 case SPECIAL_MOD_ASSIGN:
899 return '%';
900 case SPECIAL_AND_ASSIGN:
901 return '&';
902 case SPECIAL_OR_ASSIGN:
903 return '|';
904 case SPECIAL_XOR_ASSIGN:
905 return '^';
906 case SPECIAL_SHL_ASSIGN:
907 return SPECIAL_LEFTSHIFT;
908 case SPECIAL_SHR_ASSIGN:
909 return SPECIAL_RIGHTSHIFT;
910 default:
911 return op;
912 }
913 }
914
915 static void match_assign(struct expression *expr)
916 {
917 struct range_list *rl = NULL;
918 struct expression *left;
919 struct expression *right;
920 struct expression *binop_expr;
921 struct symbol *left_type;
922 struct symbol *sym;
923 char *name;
924 sval_t left_min, left_max;
925 sval_t right_min, right_max;
926 sval_t res_min, res_max;
927
928 left = strip_expr(expr->left);
929
930 right = strip_parens(expr->right);
931 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
932 right = get_argument_from_call_expr(right->args, 0);
933 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
934 right = strip_parens(right->left);
935
936 if (expr->op == '=' && is_condition(expr->right))
937 return; /* handled in smatch_condition.c */
938 if (expr->op == '=' && right->type == EXPR_CALL)
939 return; /* handled in smatch_function_hooks.c */
940 if (expr->op == '=') {
941 match_vanilla_assign(left, right);
942 return;
943 }
944
945 name = expr_to_var_sym(left, &sym);
946 if (!name)
947 return;
948
949 left_type = get_type(left);
950
951 res_min = sval_type_min(left_type);
952 res_max = sval_type_max(left_type);
953
954 switch (expr->op) {
955 case SPECIAL_ADD_ASSIGN:
956 get_absolute_max(left, &left_max);
957 get_absolute_max(right, &right_max);
958 if (sval_binop_overflows(left_max, '+', sval_cast(left_type, right_max)))
959 break;
960 if (get_implied_min(left, &left_min) &&
961 !sval_is_negative_min(left_min) &&
962 get_implied_min(right, &right_min) &&
963 !sval_is_negative_min(right_min)) {
964 res_min = sval_binop(left_min, '+', right_min);
965 res_min = sval_cast(left_type, res_min);
966 }
967 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
968 break;
969 res_max = sval_binop(left_max, '+', right_max);
970 res_max = sval_cast(left_type, res_max);
971 break;
972 case SPECIAL_SUB_ASSIGN:
973 if (get_implied_max(left, &left_max) &&
974 !sval_is_max(left_max) &&
975 get_implied_min(right, &right_min) &&
976 !sval_is_min(right_min)) {
977 res_max = sval_binop(left_max, '-', right_min);
978 res_max = sval_cast(left_type, res_max);
979 }
980 if (inside_loop())
981 break;
982 if (get_implied_min(left, &left_min) &&
983 !sval_is_min(left_min) &&
984 get_implied_max(right, &right_max) &&
985 !sval_is_max(right_max)) {
986 res_min = sval_binop(left_min, '-', right_max);
987 res_min = sval_cast(left_type, res_min);
988 }
989 break;
990 case SPECIAL_AND_ASSIGN:
991 case SPECIAL_MOD_ASSIGN:
992 case SPECIAL_SHL_ASSIGN:
993 case SPECIAL_SHR_ASSIGN:
994 case SPECIAL_OR_ASSIGN:
995 case SPECIAL_XOR_ASSIGN:
996 case SPECIAL_MUL_ASSIGN:
997 case SPECIAL_DIV_ASSIGN:
998 binop_expr = binop_expression(expr->left,
999 op_remove_assign(expr->op),
1000 expr->right);
1001 if (get_absolute_rl(binop_expr, &rl)) {
1002 rl = cast_rl(left_type, rl);
1003 set_extra_mod(name, sym, alloc_estate_rl(rl));
1004 goto free;
1005 }
1006 break;
1007 }
1008 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
1009 set_extra_mod(name, sym, alloc_estate_rl(rl));
1010 free:
1011 free_string(name);
1012 }
1013
1014 static struct smatch_state *increment_state(struct smatch_state *state)
1015 {
1016 sval_t min = estate_min(state);
1017 sval_t max = estate_max(state);
1018
1019 if (!estate_rl(state))
1020 return NULL;
1021
1022 if (inside_loop())
1023 max = sval_type_max(max.type);
1024
1025 if (!sval_is_min(min) && !sval_is_max(min))
1026 min.value++;
1027 if (!sval_is_min(max) && !sval_is_max(max))
1028 max.value++;
1029 return alloc_estate_range(min, max);
1030 }
1031
1032 static struct smatch_state *decrement_state(struct smatch_state *state)
1033 {
1034 sval_t min = estate_min(state);
1035 sval_t max = estate_max(state);
1036
1037 if (!estate_rl(state))
1038 return NULL;
1039
1040 if (inside_loop())
1041 min = sval_type_min(min.type);
1042
1043 if (!sval_is_min(min) && !sval_is_max(min))
1044 min.value--;
1045 if (!sval_is_min(max) && !sval_is_max(max))
1046 max.value--;
1047 return alloc_estate_range(min, max);
1048 }
1049
1050 static void clear_pointed_at_state(struct expression *expr)
1051 {
1052 struct symbol *type;
1053
1054 /*
1055 * ALERT: This is sort of a mess. If it's is a struct assigment like
1056 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1057 * the same thing for p++ where "p" is a struct. Most modifications
1058 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1059 * use smatch_modification.c because we have to get the ordering right
1060 * or something. So if you have p++ where p is a pointer to a standard
1061 * c type then we handle that here. What a mess.
1062 */
1063
1064 type = get_type(expr);
1065 if (!type || type->type != SYM_PTR)
1066 return;
1067 type = get_real_base_type(type);
1068 if (!type || type->type != SYM_BASETYPE)
1069 return;
1070 set_extra_expr_mod(deref_expression(expr), alloc_estate_whole(type));
1071 }
1072
1073 static void unop_expr(struct expression *expr)
1074 {
1075 struct smatch_state *state;
1076
1077 if (expr->smatch_flags & Handled)
1078 return;
1079
1080 switch (expr->op) {
1081 case SPECIAL_INCREMENT:
1082 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1083 state = increment_state(state);
1084 if (!state)
1085 state = alloc_estate_whole(get_type(expr));
1086 set_extra_expr_mod(expr->unop, state);
1087 clear_pointed_at_state(expr->unop);
1088 break;
1089 case SPECIAL_DECREMENT:
1090 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1091 state = decrement_state(state);
1092 if (!state)
1093 state = alloc_estate_whole(get_type(expr));
1094 set_extra_expr_mod(expr->unop, state);
1095 clear_pointed_at_state(expr->unop);
1096 break;
1097 default:
1098 return;
1099 }
1100 }
1101
1102 static void asm_expr(struct statement *stmt)
1103 {
1104
1105 struct expression *expr;
1106 struct symbol *type;
1107 int state = 0;
1108
1109 FOR_EACH_PTR(stmt->asm_outputs, expr) {
1110 switch (state) {
1111 case 0: /* identifier */
1112 case 1: /* constraint */
1113 state++;
1114 continue;
1115 case 2: /* expression */
1116 state = 0;
1117 type = get_type(strip_expr(expr));
1118 set_extra_expr_mod(expr, alloc_estate_whole(type));
1119 continue;
1120 }
1121 } END_FOR_EACH_PTR(expr);
1122 }
1123
1124 static void check_dereference(struct expression *expr)
1125 {
1126 struct smatch_state *state;
1127
1128 if (__in_fake_assign)
1129 return;
1130 if (outside_of_function())
1131 return;
1132 state = get_extra_state(expr);
1133 if (state) {
1134 static struct range_list *valid_rl;
1135 struct range_list *rl;
1136
1137 if (!valid_rl) {
1138 valid_rl = alloc_rl(valid_ptr_min_sval, valid_ptr_max_sval);
1139 valid_rl = clone_rl_permanent(valid_rl);
1140 }
1141
1142 rl = rl_intersection(estate_rl(state), valid_rl);
1143 if (rl_equiv(rl, estate_rl(state)))
1144 return;
1145 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1146 } else {
1147 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1148 }
1149 }
1150
1151 static void match_dereferences(struct expression *expr)
1152 {
1153 if (expr->type != EXPR_PREOP)
1154 return;
1155 /* it's saying that foo[1] = bar dereferences foo[1] */
1156 if (is_array(expr))
1157 return;
1158 check_dereference(expr->unop);
1159 }
1160
1161 static void match_pointer_as_array(struct expression *expr)
1162 {
1163 if (!is_array(expr))
1164 return;
1165 check_dereference(get_array_base(expr));
1166 }
1167
1168 static void find_dereferences(struct expression *expr)
1169 {
1170 while (expr->type == EXPR_PREOP) {
1171 if (expr->op == '*')
1172 check_dereference(expr->unop);
1173 expr = strip_expr(expr->unop);
1174 }
1175 }
1176
1177 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
1178 {
1179 struct symbol *sym;
1180 char *name;
1181
1182 name = get_variable_from_key(arg, key, &sym);
1183 if (name && sym) {
1184 struct smatch_state *orig, *new;
1185 struct range_list *rl;
1186
1187 orig = get_state(SMATCH_EXTRA, name, sym);
1188 if (orig) {
1189 rl = rl_intersection(estate_rl(orig),
1190 alloc_rl(valid_ptr_min_sval,
1191 valid_ptr_max_sval));
1192 new = alloc_estate_rl(rl);
1193 } else {
1194 new = alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval);
1195 }
1196
1197 set_extra_nomod(name, sym, new);
1198 }
1199 free_string(name);
1200
1201 find_dereferences(arg);
1202 }
1203
1204 static sval_t add_one(sval_t sval)
1205 {
1206 sval.value++;
1207 return sval;
1208 }
1209
1210 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1211 {
1212 struct statement *stmt;
1213 struct expression *cond;
1214 struct smatch_state *true_state, *false_state;
1215 sval_t start;
1216 sval_t limit;
1217
1218 /*
1219 * If we're decrementing here then that's a canonical while count down
1220 * so it's handled already. We're only handling loops like:
1221 * i = 0;
1222 * do { ... } while (i++ < 3);
1223 */
1224
1225 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1226 return 0;
1227
1228 stmt = __cur_stmt->parent;
1229 if (!stmt)
1230 return 0;
1231 if (stmt->type == STMT_COMPOUND)
1232 stmt = stmt->parent;
1233 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1234 return 0;
1235
1236 cond = strip_expr(stmt->iterator_post_condition);
1237 if (cond->type != EXPR_COMPARE || cond->op != op)
1238 return 0;
1239 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1240 return 0;
1241
1242 if (!get_implied_value(left->unop, &start))
1243 return 0;
1244 if (!get_implied_value(right, &limit))
1245 return 0;
1246
1247 if (sval_cmp(start, limit) > 0)
1248 return 0;
1249
1250 switch (op) {
1251 case '<':
1252 case SPECIAL_UNSIGNED_LT:
1253 break;
1254 case SPECIAL_LTE:
1255 case SPECIAL_UNSIGNED_LTE:
1256 limit = add_one(limit);
1257 default:
1258 return 0;
1259
1260 }
1261
1262 true_state = alloc_estate_range(add_one(start), limit);
1263 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1264
1265 /* Currently we just discard the false state but when two passes is
1266 * implimented correctly then it will use it.
1267 */
1268
1269 set_extra_expr_true_false(left->unop, true_state, false_state);
1270
1271 return 1;
1272 }
1273
1274 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1275 {
1276 struct range_list *left_orig;
1277 struct range_list *left_true;
1278 struct range_list *left_false;
1279 struct range_list *right_orig;
1280 struct range_list *right_true;
1281 struct range_list *right_false;
1282 struct smatch_state *left_true_state;
1283 struct smatch_state *left_false_state;
1284 struct smatch_state *right_true_state;
1285 struct smatch_state *right_false_state;
1286 sval_t dummy, hard_max;
1287 int left_postop = 0;
1288 int right_postop = 0;
1289
1290 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1291 if (left->type == EXPR_POSTOP) {
1292 left->smatch_flags |= Handled;
1293 left_postop = left->op;
1294 if (handle_postop_inc(left, op, right))
1295 return;
1296 }
1297 left = strip_parens(left->unop);
1298 }
1299 while (left->type == EXPR_ASSIGNMENT)
1300 left = strip_parens(left->left);
1301
1302 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1303 if (right->type == EXPR_POSTOP) {
1304 right->smatch_flags |= Handled;
1305 right_postop = right->op;
1306 }
1307 right = strip_parens(right->unop);
1308 }
1309
1310 get_real_absolute_rl(left, &left_orig);
1311 left_orig = cast_rl(type, left_orig);
1312
1313 get_real_absolute_rl(right, &right_orig);
1314 right_orig = cast_rl(type, right_orig);
1315
1316 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1317
1318 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1319 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1320 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1321 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1322
1323 if (!left_true || !left_false) {
1324 struct range_list *tmp_true, *tmp_false;
1325
1326 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1327 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1328 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1329 if (tmp_true && tmp_false)
1330 __save_imaginary_state(left, tmp_true, tmp_false);
1331 }
1332
1333 if (!right_true || !right_false) {
1334 struct range_list *tmp_true, *tmp_false;
1335
1336 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1337 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1338 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1339 if (tmp_true && tmp_false)
1340 __save_imaginary_state(right, tmp_true, tmp_false);
1341 }
1342
1343 left_true_state = alloc_estate_rl(left_true);
1344 left_false_state = alloc_estate_rl(left_false);
1345 right_true_state = alloc_estate_rl(right_true);
1346 right_false_state = alloc_estate_rl(right_false);
1347
1348 switch (op) {
1349 case '<':
1350 case SPECIAL_UNSIGNED_LT:
1351 case SPECIAL_UNSIGNED_LTE:
1352 case SPECIAL_LTE:
1353 if (get_hard_max(right, &dummy))
1354 estate_set_hard_max(left_true_state);
1355 if (get_hard_max(left, &dummy))
1356 estate_set_hard_max(right_false_state);
1357 break;
1358 case '>':
1359 case SPECIAL_UNSIGNED_GT:
1360 case SPECIAL_UNSIGNED_GTE:
1361 case SPECIAL_GTE:
1362 if (get_hard_max(left, &dummy))
1363 estate_set_hard_max(right_true_state);
1364 if (get_hard_max(right, &dummy))
1365 estate_set_hard_max(left_false_state);
1366 break;
1367 }
1368
1369 switch (op) {
1370 case '<':
1371 case SPECIAL_UNSIGNED_LT:
1372 case SPECIAL_UNSIGNED_LTE:
1373 case SPECIAL_LTE:
1374 if (get_hard_max(right, &hard_max)) {
1375 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1376 hard_max.value--;
1377 estate_set_fuzzy_max(left_true_state, hard_max);
1378 }
1379 if (get_implied_value(right, &hard_max)) {
1380 if (op == SPECIAL_UNSIGNED_LTE ||
1381 op == SPECIAL_LTE)
1382 hard_max.value++;
1383 estate_set_fuzzy_max(left_false_state, hard_max);
1384 }
1385 if (get_hard_max(left, &hard_max)) {
1386 if (op == SPECIAL_UNSIGNED_LTE ||
1387 op == SPECIAL_LTE)
1388 hard_max.value--;
1389 estate_set_fuzzy_max(right_false_state, hard_max);
1390 }
1391 if (get_implied_value(left, &hard_max)) {
1392 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1393 hard_max.value++;
1394 estate_set_fuzzy_max(right_true_state, hard_max);
1395 }
1396 break;
1397 case '>':
1398 case SPECIAL_UNSIGNED_GT:
1399 case SPECIAL_UNSIGNED_GTE:
1400 case SPECIAL_GTE:
1401 if (get_hard_max(left, &hard_max)) {
1402 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1403 hard_max.value--;
1404 estate_set_fuzzy_max(right_true_state, hard_max);
1405 }
1406 if (get_implied_value(left, &hard_max)) {
1407 if (op == SPECIAL_UNSIGNED_GTE ||
1408 op == SPECIAL_GTE)
1409 hard_max.value++;
1410 estate_set_fuzzy_max(right_false_state, hard_max);
1411 }
1412 if (get_hard_max(right, &hard_max)) {
1413 if (op == SPECIAL_UNSIGNED_LTE ||
1414 op == SPECIAL_LTE)
1415 hard_max.value--;
1416 estate_set_fuzzy_max(left_false_state, hard_max);
1417 }
1418 if (get_implied_value(right, &hard_max)) {
1419 if (op == '>' ||
1420 op == SPECIAL_UNSIGNED_GT)
1421 hard_max.value++;
1422 estate_set_fuzzy_max(left_true_state, hard_max);
1423 }
1424 break;
1425 case SPECIAL_EQUAL:
1426 if (get_hard_max(left, &hard_max))
1427 estate_set_fuzzy_max(right_true_state, hard_max);
1428 if (get_hard_max(right, &hard_max))
1429 estate_set_fuzzy_max(left_true_state, hard_max);
1430 break;
1431 }
1432
1433 if (get_hard_max(left, &hard_max)) {
1434 estate_set_hard_max(left_true_state);
1435 estate_set_hard_max(left_false_state);
1436 }
1437 if (get_hard_max(right, &hard_max)) {
1438 estate_set_hard_max(right_true_state);
1439 estate_set_hard_max(right_false_state);
1440 }
1441
1442 if (left_postop == SPECIAL_INCREMENT) {
1443 left_true_state = increment_state(left_true_state);
1444 left_false_state = increment_state(left_false_state);
1445 }
1446 if (left_postop == SPECIAL_DECREMENT) {
1447 left_true_state = decrement_state(left_true_state);
1448 left_false_state = decrement_state(left_false_state);
1449 }
1450 if (right_postop == SPECIAL_INCREMENT) {
1451 right_true_state = increment_state(right_true_state);
1452 right_false_state = increment_state(right_false_state);
1453 }
1454 if (right_postop == SPECIAL_DECREMENT) {
1455 right_true_state = decrement_state(right_true_state);
1456 right_false_state = decrement_state(right_false_state);
1457 }
1458
1459 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1460 left_true_state = NULL;
1461 left_false_state = NULL;
1462 }
1463
1464 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1465 right_true_state = NULL;
1466 right_false_state = NULL;
1467 }
1468
1469 set_extra_expr_true_false(left, left_true_state, left_false_state);
1470 set_extra_expr_true_false(right, right_true_state, right_false_state);
1471 }
1472
1473 static int is_simple_math(struct expression *expr)
1474 {
1475 if (!expr)
1476 return 0;
1477 if (expr->type != EXPR_BINOP)
1478 return 0;
1479 switch (expr->op) {
1480 case '+':
1481 case '-':
1482 case '*':
1483 return 1;
1484 }
1485 return 0;
1486 }
1487
1488 static void move_known_values(struct expression **left_p, struct expression **right_p)
1489 {
1490 struct expression *left = *left_p;
1491 struct expression *right = *right_p;
1492 sval_t sval, dummy;
1493
1494 if (get_implied_value(left, &sval)) {
1495 if (!is_simple_math(right))
1496 return;
1497 if (get_implied_value(right, &dummy))
1498 return;
1499 if (right->op == '*') {
1500 sval_t divisor;
1501
1502 if (!get_value(right->right, &divisor))
1503 return;
1504 if (divisor.value == 0 && sval.value % divisor.value)
1505 return;
1506 *left_p = binop_expression(left, invert_op(right->op), right->right);
1507 *right_p = right->left;
1508 return;
1509 }
1510 if (right->op == '+' && get_value(right->left, &sval)) {
1511 *left_p = binop_expression(left, invert_op(right->op), right->left);
1512 *right_p = right->right;
1513 return;
1514 }
1515 if (get_value(right->right, &sval)) {
1516 *left_p = binop_expression(left, invert_op(right->op), right->right);
1517 *right_p = right->left;
1518 return;
1519 }
1520 return;
1521 }
1522 if (get_implied_value(right, &sval)) {
1523 if (!is_simple_math(left))
1524 return;
1525 if (get_implied_value(left, &dummy))
1526 return;
1527 if (left->op == '*') {
1528 sval_t divisor;
1529
1530 if (!get_value(left->right, &divisor))
1531 return;
1532 if (divisor.value == 0 && sval.value % divisor.value)
1533 return;
1534 *right_p = binop_expression(right, invert_op(left->op), left->right);
1535 *left_p = left->left;
1536 return;
1537 }
1538 if (left->op == '+' && get_value(left->left, &sval)) {
1539 *right_p = binop_expression(right, invert_op(left->op), left->left);
1540 *left_p = left->right;
1541 return;
1542 }
1543
1544 if (get_value(left->right, &sval)) {
1545 *right_p = binop_expression(right, invert_op(left->op), left->right);
1546 *left_p = left->left;
1547 return;
1548 }
1549 return;
1550 }
1551 }
1552
1553 /*
1554 * The reason for do_simple_algebra() is to solve things like:
1555 * if (foo > 66 || foo + bar > 64) {
1556 * "foo" is not really a known variable so it won't be handled by
1557 * move_known_variables() but it's a super common idiom.
1558 *
1559 */
1560 static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
1561 {
1562 struct expression *left = *left_p;
1563 struct expression *right = *right_p;
1564 struct range_list *rl;
1565 sval_t tmp;
1566
1567 if (left->type != EXPR_BINOP || left->op != '+')
1568 return 0;
1569 if (can_integer_overflow(get_type(left), left))
1570 return 0;
1571 if (!get_implied_value(right, &tmp))
1572 return 0;
1573
1574 if (!get_implied_value(left->left, &tmp) &&
1575 get_implied_rl(left->left, &rl) &&
1576 !is_whole_rl(rl)) {
1577 *right_p = binop_expression(right, '-', left->left);
1578 *left_p = left->right;
1579 return 1;
1580 }
1581 if (!get_implied_value(left->right, &tmp) &&
1582 get_implied_rl(left->right, &rl) &&
1583 !is_whole_rl(rl)) {
1584 *right_p = binop_expression(right, '-', left->right);
1585 *left_p = left->left;
1586 return 1;
1587 }
1588
1589 return 0;
1590 }
1591
1592 static int match_func_comparison(struct expression *expr)
1593 {
1594 struct expression *left = strip_expr(expr->left);
1595 struct expression *right = strip_expr(expr->right);
1596 sval_t sval;
1597
1598 /*
1599 * fixme: think about this harder. We should always be trying to limit
1600 * the non-call side as well. If we can't determine the limitter does
1601 * that mean we aren't querying the database and are missing important
1602 * information?
1603 */
1604
1605 if (left->type == EXPR_CALL) {
1606 if (get_implied_value(left, &sval)) {
1607 handle_comparison(get_type(expr), left, expr->op, right);
1608 return 1;
1609 }
1610 function_comparison(left, expr->op, right);
1611 return 1;
1612 }
1613
1614 if (right->type == EXPR_CALL) {
1615 if (get_implied_value(right, &sval)) {
1616 handle_comparison(get_type(expr), left, expr->op, right);
1617 return 1;
1618 }
1619 function_comparison(left, expr->op, right);
1620 return 1;
1621 }
1622
1623 return 0;
1624 }
1625
1626 /* Handle conditions like "if (foo + bar < foo) {" */
1627 static int handle_integer_overflow_test(struct expression *expr)
1628 {
1629 struct expression *left, *right;
1630 struct symbol *type;
1631 sval_t left_min, right_min, min, max;
1632
1633 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
1634 return 0;
1635
1636 left = strip_parens(expr->left);
1637 right = strip_parens(expr->right);
1638
1639 if (left->op != '+')
1640 return 0;
1641
1642 type = get_type(expr);
1643 if (!type)
1644 return 0;
1645 if (type_positive_bits(type) == 32) {
1646 max.type = &uint_ctype;
1647 max.uvalue = (unsigned int)-1;
1648 } else if (type_positive_bits(type) == 64) {
1649 max.type = &ulong_ctype;
1650 max.value = (unsigned long long)-1;
1651 } else {
1652 return 0;
1653 }
1654
1655 if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
1656 return 0;
1657
1658 get_absolute_min(left->left, &left_min);
1659 get_absolute_min(left->right, &right_min);
1660 min = sval_binop(left_min, '+', right_min);
1661
1662 set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
1663 return 1;
1664 }
1665
1666 static void match_comparison(struct expression *expr)
1667 {
1668 struct expression *left_orig = strip_parens(expr->left);
1669 struct expression *right_orig = strip_parens(expr->right);
1670 struct expression *left, *right;
1671 struct expression *prev;
1672 struct symbol *type;
1673
1674 if (match_func_comparison(expr))
1675 return;
1676
1677 type = get_type(expr);
1678 if (!type)
1679 type = &llong_ctype;
1680
1681 if (handle_integer_overflow_test(expr))
1682 return;
1683
1684 left = left_orig;
1685 right = right_orig;
1686 move_known_values(&left, &right);
1687 handle_comparison(type, left, expr->op, right);
1688
1689 left = left_orig;
1690 right = right_orig;
1691 if (do_simple_algebra(&left, &right))
1692 handle_comparison(type, left, expr->op, right);
1693
1694 prev = get_assigned_expr(left_orig);
1695 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1696 left = prev;
1697 right = right_orig;
1698 move_known_values(&left, &right);
1699 handle_comparison(type, left, expr->op, right);
1700 }
1701
1702 prev = get_assigned_expr(right_orig);
1703 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1704 left = left_orig;
1705 right = prev;
1706 move_known_values(&left, &right);
1707 handle_comparison(type, left, expr->op, right);
1708 }
1709 }
1710
1711 static sval_t get_high_mask(sval_t known)
1712 {
1713 sval_t ret;
1714 int i;
1715
1716 ret = known;
1717 ret.value = 0;
1718
1719 for (i = type_bits(known.type) - 1; i >= 0; i--) {
1720 if (known.uvalue & (1ULL << i))
1721 ret.uvalue |= (1ULL << i);
1722 else
1723 return ret;
1724
1725 }
1726 return ret;
1727 }
1728
1729 static void handle_AND_condition(struct expression *expr)
1730 {
1731 struct range_list *orig_rl;
1732 struct range_list *true_rl = NULL;
1733 struct range_list *false_rl = NULL;
1734 sval_t known;
1735 int bit;
1736
1737 if (get_implied_value(expr->left, &known)) {
1738 sval_t low_mask = known;
1739 sval_t high_mask;
1740
1741 if (known.value > 0) {
1742 bit = ffsll(known.value) - 1;
1743 low_mask.uvalue = (1ULL << bit) - 1;
1744 get_absolute_rl(expr->right, &orig_rl);
1745 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
1746 }
1747 high_mask = get_high_mask(known);
1748 if (high_mask.value) {
1749 bit = ffsll(high_mask.value) - 1;
1750 low_mask.uvalue = (1ULL << bit) - 1;
1751
1752 get_absolute_rl(expr->left, &orig_rl);
1753 if (sval_is_negative(rl_min(orig_rl)))
1754 orig_rl = remove_range(orig_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
1755 false_rl = remove_range(orig_rl, low_mask, sval_type_max(known.type));
1756 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
1757 false_rl = remove_range(false_rl,
1758 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
1759 sval_type_val(rl_type(false_rl), -1));
1760 }
1761 }
1762 set_extra_expr_true_false(expr->right,
1763 true_rl ? alloc_estate_rl(true_rl) : NULL,
1764 false_rl ? alloc_estate_rl(false_rl) : NULL);
1765
1766 return;
1767 }
1768
1769 if (get_implied_value(expr->right, &known)) {
1770 sval_t low_mask = known;
1771 sval_t high_mask;
1772
1773 if (known.value > 0) {
1774 bit = ffsll(known.value) - 1;
1775 low_mask.uvalue = (1ULL << bit) - 1;
1776 get_absolute_rl(expr->left, &orig_rl);
1777 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
1778 }
1779 high_mask = get_high_mask(known);
1780 if (high_mask.value) {
1781 bit = ffsll(high_mask.value) - 1;
1782 low_mask.uvalue = (1ULL << bit) - 1;
1783
1784 get_absolute_rl(expr->left, &orig_rl);
1785 if (sval_is_negative(rl_min(orig_rl)))
1786 orig_rl = remove_range(orig_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
1787 false_rl = remove_range(orig_rl, low_mask, sval_type_max(known.type));
1788 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
1789 false_rl = remove_range(false_rl,
1790 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
1791 sval_type_val(rl_type(false_rl), -1));
1792 }
1793 }
1794 set_extra_expr_true_false(expr->left,
1795 true_rl ? alloc_estate_rl(true_rl) : NULL,
1796 false_rl ? alloc_estate_rl(false_rl) : NULL);
1797 return;
1798 }
1799 }
1800
1801 static void handle_MOD_condition(struct expression *expr)
1802 {
1803 struct range_list *orig_rl;
1804 struct range_list *true_rl;
1805 struct range_list *false_rl = NULL;
1806 sval_t right;
1807 sval_t zero = {
1808 .value = 0,
1809 };
1810
1811 if (!get_implied_value(expr->right, &right) || right.value == 0)
1812 return;
1813 get_absolute_rl(expr->left, &orig_rl);
1814
1815 zero.type = rl_type(orig_rl);
1816
1817 /* We're basically dorking around the min and max here */
1818 true_rl = remove_range(orig_rl, zero, zero);
1819 if (!sval_is_max(rl_max(true_rl)) &&
1820 !(rl_max(true_rl).value % right.value))
1821 true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));
1822
1823 if (rl_equiv(true_rl, orig_rl))
1824 true_rl = NULL;
1825
1826 if (sval_is_positive(rl_min(orig_rl)) &&
1827 (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
1828 sval_t add;
1829 int i;
1830
1831 add = rl_min(orig_rl);
1832 add.value += right.value - (add.value % right.value);
1833 add.value -= right.value;
1834
1835 for (i = 0; i < 5; i++) {
1836 add.value += right.value;
1837 if (add.value > rl_max(orig_rl).value)
1838 break;
1839 add_range(&false_rl, add, add);
1840 }
1841 } else {
1842 if (rl_min(orig_rl).uvalue != 0 &&
1843 rl_min(orig_rl).uvalue < right.uvalue) {
1844 sval_t chop = right;
1845 chop.value--;
1846 false_rl = remove_range(orig_rl, zero, chop);
1847 }
1848
1849 if (!sval_is_max(rl_max(orig_rl)) &&
1850 (rl_max(orig_rl).value % right.value)) {
1851 sval_t chop = rl_max(orig_rl);
1852 chop.value -= chop.value % right.value;
1853 chop.value++;
1854 if (!false_rl)
1855 false_rl = clone_rl(orig_rl);
1856 false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
1857 }
1858 }
1859
1860 set_extra_expr_true_false(expr->left,
1861 true_rl ? alloc_estate_rl(true_rl) : NULL,
1862 false_rl ? alloc_estate_rl(false_rl) : NULL);
1863 }
1864
1865 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1866 void __extra_match_condition(struct expression *expr)
1867 {
1868 struct smatch_state *pre_state;
1869 struct smatch_state *true_state;
1870 struct smatch_state *false_state;
1871 struct range_list *pre_rl;
1872
1873 expr = strip_expr(expr);
1874 switch (expr->type) {
1875 case EXPR_CALL:
1876 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1877 return;
1878 case EXPR_PREOP:
1879 case EXPR_SYMBOL:
1880 case EXPR_DEREF: {
1881 sval_t zero;
1882
1883 zero = sval_blank(expr);
1884 zero.value = 0;
1885
1886 pre_state = get_extra_state(expr);
1887 if (estate_is_empty(pre_state))
1888 return;
1889 if (pre_state)
1890 pre_rl = estate_rl(pre_state);
1891 else
1892 get_absolute_rl(expr, &pre_rl);
1893 if (possibly_true_rl(pre_rl, SPECIAL_EQUAL, rl_zero()))
1894 false_state = alloc_estate_sval(zero);
1895 else
1896 false_state = alloc_estate_empty();
1897 true_state = alloc_estate_rl(remove_range(pre_rl, zero, zero));
1898 set_extra_expr_true_false(expr, true_state, false_state);
1899 return;
1900 }
1901 case EXPR_COMPARE:
1902 match_comparison(expr);
1903 return;
1904 case EXPR_ASSIGNMENT:
1905 __extra_match_condition(expr->left);
1906 return;
1907 case EXPR_BINOP:
1908 if (expr->op == '&')
1909 handle_AND_condition(expr);
1910 if (expr->op == '%')
1911 handle_MOD_condition(expr);
1912 return;
1913 }
1914 }
1915
1916 static void assume_indexes_are_valid(struct expression *expr)
1917 {
1918 struct expression *array_expr;
1919 int array_size;
1920 struct expression *offset;
1921 struct symbol *offset_type;
1922 struct range_list *rl_before;
1923 struct range_list *rl_after;
1924 struct range_list *filter = NULL;
1925 sval_t size;
1926
1927 expr = strip_expr(expr);
1928 if (!is_array(expr))
1929 return;
1930
1931 offset = get_array_offset(expr);
1932 offset_type = get_type(offset);
1933 if (offset_type && type_signed(offset_type)) {
1934 filter = alloc_rl(sval_type_min(offset_type),
1935 sval_type_val(offset_type, -1));
1936 }
1937
1938 array_expr = get_array_base(expr);
1939 array_size = get_real_array_size(array_expr);
1940 if (array_size > 1) {
1941 size = sval_type_val(offset_type, array_size);
1942 add_range(&filter, size, sval_type_max(offset_type));
1943 }
1944
1945 if (!filter)
1946 return;
1947 get_absolute_rl(offset, &rl_before);
1948 rl_after = rl_filter(rl_before, filter);
1949 if (rl_equiv(rl_before, rl_after))
1950 return;
1951 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1952 }
1953
1954 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1955 int implied_not_equal(struct expression *expr, long long val)
1956 {
1957 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1958 }
1959
1960 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1961 {
1962 struct smatch_state *estate;
1963
1964 estate = get_state(SMATCH_EXTRA, name, sym);
1965 if (!estate)
1966 return 0;
1967 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1968 return 1;
1969 return 0;
1970 }
1971
1972 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1973 {
1974 char buf[256];
1975 char *start;
1976 char *end;
1977 struct smatch_state *state;
1978
1979 strncpy(buf, name, sizeof(buf) - 1);
1980 buf[sizeof(buf) - 1] = '\0';
1981
1982 start = &buf[0];
1983 while (*start == '*') {
1984 start++;
1985 state = get_state(SMATCH_EXTRA, start, sym);
1986 if (!state)
1987 continue;
1988 if (!estate_rl(state))
1989 return 1;
1990 if (estate_min(state).value == 0 &&
1991 estate_max(state).value == 0)
1992 return 1;
1993 }
1994
1995 start = &buf[0];
1996 while (*start == '&')
1997 start++;
1998
1999 while ((end = strrchr(start, '-'))) {
2000 *end = '\0';
2001 state = __get_state(SMATCH_EXTRA, start, sym);
2002 if (!state)
2003 continue;
2004 if (estate_min(state).value == 0 &&
2005 estate_max(state).value == 0)
2006 return 1;
2007 }
2008 return 0;
2009 }
2010
2011 int parent_is_null(struct expression *expr)
2012 {
2013 struct symbol *sym;
2014 char *var;
2015 int ret = 0;
2016
2017 expr = strip_expr(expr);
2018 var = expr_to_var_sym(expr, &sym);
2019 if (!var || !sym)
2020 goto free;
2021 ret = parent_is_null_var_sym(var, sym);
2022 free:
2023 free_string(var);
2024 return ret;
2025 }
2026
2027 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
2028 {
2029 *(int *)found = 1;
2030 return 0;
2031 }
2032
2033 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2034 {
2035 sval_t sval;
2036 int found = 0;
2037
2038 /* for function pointers assume everything is used */
2039 if (call->fn->type != EXPR_SYMBOL)
2040 return 0;
2041
2042 /*
2043 * kzalloc() information is treated as special because so there is just
2044 * a lot of stuff initialized to zero and it makes building the database
2045 * take hours and hours.
2046 *
2047 * In theory, we should just remove this line and not pass any unused
2048 * information, but I'm not sure enough that this code works so I want
2049 * to hold off on that for now.
2050 */
2051 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
2052 return 0;
2053
2054 run_sql(&param_used_callback, &found,
2055 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
2056 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
2057 if (found)
2058 return 0;
2059
2060 /* If the database is not built yet, then assume everything is used */
2061 run_sql(&param_used_callback, &found,
2062 "select * from call_implies where %s and type = %d;",
2063 get_static_filter(call->fn->symbol), PARAM_USED);
2064 if (!found)
2065 return 0;
2066
2067 return 1;
2068 }
2069
2070 struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
2071 {
2072 struct smatch_state *state;
2073
2074 /*
2075 * Here is the difference between implied value and real absolute, say
2076 * you have:
2077 *
2078 * int a = (u8)x;
2079 *
2080 * Then you know that a is 0-255. That's real absolute. But you don't
2081 * know for sure that it actually goes up to 255. So it's not implied.
2082 * Implied indicates a degree of certainty.
2083 *
2084 * But then say you cap "a" at 8. That means you know it goes up to
2085 * 8. So now the implied value is s32min-8. But you can combine it
2086 * with the real absolute to say that actually it's 0-8.
2087 *
2088 * We are combining it here. But now that I think about it, this is
2089 * probably not the ideal place to combine it because it should proably
2090 * be done earlier. Oh well, this is an improvement on what was there
2091 * before so I'm going to commit this code.
2092 *
2093 */
2094
2095 state = get_real_absolute_state_var_sym(name, sym);
2096 if (!state || !estate_rl(state))
2097 return start;
2098
2099 return rl_intersection(estate_rl(state), start);
2100 }
2101
2102 struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
2103 {
2104 struct smatch_state *state;
2105
2106 state = get_real_absolute_state(expr);
2107 if (!state || !estate_rl(state))
2108 return start;
2109
2110 return rl_intersection(estate_rl(state), start);
2111 }
2112
2113 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2114 {
2115 struct range_list *rl;
2116
2117 if (estate_is_whole(sm->state))
2118 return;
2119 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
2120 return;
2121 rl = estate_rl(sm->state);
2122 rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
2123 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
2124 if (estate_has_fuzzy_max(sm->state))
2125 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
2126 sval_to_str(estate_get_fuzzy_max(sm->state)));
2127 }
2128
2129 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
2130 {
2131 struct symbol *returned_sym;
2132 struct sm_state *sm;
2133 const char *param_name;
2134 char *compare_str;
2135 char buf[256];
2136
2137 returned_sym = expr_to_sym(expr);
2138 if (!returned_sym)
2139 return;
2140
2141 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
2142 if (!estate_rl(sm->state))
2143 continue;
2144 if (returned_sym != sm->sym)
2145 continue;
2146
2147 param_name = get_param_name(sm);
2148 if (!param_name)
2149 continue;
2150 if (strcmp(param_name, "$") == 0)
2151 continue;
2152 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
2153 if (!compare_str && estate_is_whole(sm->state))
2154 continue;
2155 snprintf(buf, sizeof(buf), "%s%s", sm->state->name, compare_str ?: "");
2156
2157 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
2158 -1, param_name, buf);
2159 } END_FOR_EACH_SM(sm);
2160 }
2161
2162 static void db_limited_before(void)
2163 {
2164 unmatched_stree = clone_stree(__get_cur_stree());
2165 }
2166
2167 static void db_limited_after(void)
2168 {
2169 free_stree(&unmatched_stree);
2170 }
2171
2172 static int rl_fits_in_type(struct range_list *rl, struct symbol *type)
2173 {
2174 if (type_bits(rl_type(rl)) <= type_bits(type))
2175 return 1;
2176 if (sval_cmp(rl_max(rl), sval_type_max(type)) > 0)
2177 return 0;
2178 if (sval_is_negative(rl_min(rl)) &&
2179 sval_cmp(rl_min(rl), sval_type_min(type)) < 0)
2180 return 0;
2181 return 1;
2182 }
2183
2184 static int basically_the_same(struct range_list *orig, struct range_list *new)
2185 {
2186 if (rl_equiv(orig, new))
2187 return 1;
2188
2189 /*
2190 * The whole range is essentially the same as 0,4096-27777777777 so
2191 * don't overwrite the implications just to store that.
2192 *
2193 */
2194 if (rl_type(orig)->type == SYM_PTR &&
2195 is_whole_rl(orig) &&
2196 rl_min(new).value == 0 &&
2197 rl_max(new).value == valid_ptr_max)
2198 return 1;
2199 return 0;
2200 }
2201
2202 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
2203 {
2204 struct expression *arg;
2205 char *name;
2206 struct symbol *sym;
2207 struct var_sym_list *vsl = NULL;
2208 struct sm_state *sm;
2209 struct symbol *compare_type, *var_type;
2210 struct range_list *rl;
2211 struct range_list *limit;
2212 struct range_list *new;
2213
2214 while (expr->type == EXPR_ASSIGNMENT)
2215 expr = strip_expr(expr->right);
2216 if (expr->type != EXPR_CALL)
2217 return;
2218
2219 arg = get_argument_from_call_expr(expr->args, param);
2220 if (!arg)
2221 return;
2222
2223 name = get_chunk_from_key(arg, key, &sym, &vsl);
2224 if (!name)
2225 return;
2226 if (op != PARAM_LIMIT && !sym)
2227 goto free;
2228
2229 if (strcmp(key, "$") == 0)
2230 compare_type = get_arg_type(expr->fn, param);
2231 else
2232 compare_type = get_member_type_from_key(arg, key);
2233
2234 sm = get_sm_state(SMATCH_EXTRA, name, sym);
2235 if (sm)
2236 rl = estate_rl(sm->state);
2237 else
2238 rl = alloc_whole_rl(compare_type);
2239
2240 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
2241 goto free;
2242
2243 call_results_to_rl(expr, compare_type, value, &limit);
2244 new = rl_intersection(rl, limit);
2245
2246 var_type = get_member_type_from_key(arg, key);
2247 new = cast_rl(var_type, new);
2248
2249 /* We want to preserve the implications here */
2250 if (sm && basically_the_same(estate_rl(sm->state), new))
2251 __set_sm(sm); /* FIXME: Is this really necessary? */
2252 else {
2253 char *tmp_name;
2254 struct symbol *tmp_sym;
2255
2256 tmp_name = map_long_to_short_name_sym(name, sym, &tmp_sym);
2257 if (tmp_name && tmp_sym) {
2258 free_string(name);
2259 name = tmp_name;
2260 sym = tmp_sym;
2261 }
2262
2263 if (op == PARAM_LIMIT)
2264 set_extra_nomod_vsl(name, sym, vsl, alloc_estate_rl(new));
2265 else
2266 set_extra_mod(name, sym, alloc_estate_rl(new));
2267 }
2268
2269 free:
2270 free_string(name);
2271 }
2272
2273 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
2274 {
2275 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
2276 }
2277
2278 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
2279 {
2280 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
2281 }
2282
2283 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
2284 {
2285 struct expression *arg;
2286 char *name, *tmp_name;
2287 struct symbol *sym, *tmp_sym;
2288 struct symbol *type;
2289 struct smatch_state *state;
2290 struct range_list *new = NULL;
2291 struct range_list *added = NULL;
2292
2293 while (expr->type == EXPR_ASSIGNMENT)
2294 expr = strip_expr(expr->right);
2295 if (expr->type != EXPR_CALL)
2296 return;
2297
2298 arg = get_argument_from_call_expr(expr->args, param);
2299 if (!arg)
2300 return;
2301 type = get_member_type_from_key(arg, key);
2302 name = get_variable_from_key(arg, key, &sym);
2303 if (!name || !sym)
2304 goto free;
2305
2306 state = get_state(SMATCH_EXTRA, name, sym);
2307 if (state)
2308 new = estate_rl(state);
2309
2310 call_results_to_rl(expr, type, value, &added);
2311
2312 if (op == PARAM_SET)
2313 new = added;
2314 else
2315 new = rl_union(new, added);
2316
2317 tmp_name = map_long_to_short_name_sym_nostack(name, sym, &tmp_sym);
2318 if (tmp_name && tmp_sym) {
2319 free_string(name);
2320 name = tmp_name;
2321 sym = tmp_sym;
2322 }
2323 set_extra_mod(name, sym, alloc_estate_rl(new));
2324 free:
2325 free_string(name);
2326 }
2327
2328 static void db_param_add(struct expression *expr, int param, char *key, char *value)
2329 {
2330 in_param_set = true;
2331 db_param_add_set(expr, param, key, value, PARAM_ADD);
2332 in_param_set = false;
2333 }
2334
2335 static void db_param_set(struct expression *expr, int param, char *key, char *value)
2336 {
2337 in_param_set = true;
2338 db_param_add_set(expr, param, key, value, PARAM_SET);
2339 in_param_set = false;
2340 }
2341
2342 static void db_param_value(struct expression *expr, int param, char *key, char *value)
2343 {
2344 struct expression *call;
2345 char *name;
2346 struct symbol *sym;
2347 struct symbol *type;
2348 struct range_list *rl = NULL;
2349
2350 if (param != -1)
2351 return;
2352
2353 call = expr;
2354 while (call->type == EXPR_ASSIGNMENT)
2355 call = strip_expr(call->right);
2356 if (call->type != EXPR_CALL)
2357 return;
2358
2359 type = get_member_type_from_key(expr->left, key);
2360 name = get_variable_from_key(expr->left, key, &sym);
2361 if (!name || !sym)
2362 goto free;
2363
2364 call_results_to_rl(call, type, value, &rl);
2365
2366 set_extra_mod(name, sym, alloc_estate_rl(rl));
2367 free:
2368 free_string(name);
2369 }
2370
2371 static void match_call_info(struct expression *expr)
2372 {
2373 struct smatch_state *state;
2374 struct range_list *rl = NULL;
2375 struct expression *arg;
2376 struct symbol *type;
2377 int i = 0;
2378
2379 FOR_EACH_PTR(expr->args, arg) {
2380 type = get_arg_type(expr->fn, i);
2381
2382 if (get_implied_rl(arg, &rl))
2383 rl = cast_rl(type, rl);
2384 else
2385 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
2386
2387 if (!is_whole_rl(rl)) {
2388 rl = intersect_with_real_abs_expr(arg, rl);
2389 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
2390 }
2391 state = get_state_expr(SMATCH_EXTRA, arg);
2392 if (estate_has_fuzzy_max(state)) {
2393 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
2394 sval_to_str(estate_get_fuzzy_max(state)));
2395 }
2396 i++;
2397 } END_FOR_EACH_PTR(arg);
2398 }
2399
2400 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2401 {
2402 struct range_list *rl = NULL;
2403 struct smatch_state *state;
2404 struct symbol *type;
2405 char fullname[256];
2406 sval_t dummy;
2407
2408 if (strcmp(key, "*$") == 0)
2409 snprintf(fullname, sizeof(fullname), "*%s", name);
2410 else if (strncmp(key, "$", 1) == 0)
2411 snprintf(fullname, 256, "%s%s", name, key + 1);
2412 else
2413 return;
2414
2415 type = get_member_type_from_key(symbol_expression(sym), key);
2416 str_to_rl(type, value, &rl);
2417 state = alloc_estate_rl(rl);
2418 if (estate_get_single_value(state, &dummy))
2419 estate_set_hard_max(state);
2420 set_state(SMATCH_EXTRA, fullname, sym, state);
2421 }
2422
2423 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2424 {
2425 struct range_list *rl = NULL;
2426 struct smatch_state *state;
2427 struct symbol *type;
2428 char fullname[256];
2429 sval_t max;
2430
2431 if (strcmp(key, "*$") == 0)
2432 snprintf(fullname, sizeof(fullname), "*%s", name);
2433 else if (strncmp(key, "$", 1) == 0)
2434 snprintf(fullname, 256, "%s%s", name, key + 1);
2435 else
2436 return;
2437
2438 state = get_state(SMATCH_EXTRA, fullname, sym);
2439 if (!state)
2440 return;
2441 type = get_member_type_from_key(symbol_expression(sym), key);
2442 str_to_rl(type, value, &rl);
2443 if (!rl_to_sval(rl, &max))
2444 return;
2445 estate_set_fuzzy_max(state, max);
2446 }
2447
2448 struct smatch_state *get_extra_state(struct expression *expr)
2449 {
2450 char *name;
2451 struct symbol *sym;
2452 struct smatch_state *ret = NULL;
2453 struct range_list *rl;
2454
2455 if (is_pointer(expr) && get_address_rl(expr, &rl))
2456 return alloc_estate_rl(rl);
2457
2458 name = expr_to_known_chunk_sym(expr, &sym);
2459 if (!name)
2460 goto free;
2461
2462 ret = get_state(SMATCH_EXTRA, name, sym);
2463 free:
2464 free_string(name);
2465 return ret;
2466 }
2467
2468 void register_smatch_extra(int id)
2469 {
2470 my_id = id;
2471
2472 add_merge_hook(my_id, &merge_estates);
2473 add_unmatched_state_hook(my_id, &unmatched_state);
2474 select_caller_info_hook(set_param_value, PARAM_VALUE);
2475 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
2476 select_return_states_before(&db_limited_before);
2477 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2478 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2479 select_return_states_hook(PARAM_ADD, &db_param_add);
2480 select_return_states_hook(PARAM_SET, &db_param_set);
2481 select_return_states_hook(PARAM_VALUE, &db_param_value);
2482 select_return_states_after(&db_limited_after);
2483 }
2484
2485 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2486 {
2487 struct var_sym_list *links;
2488 struct var_sym *tmp;
2489 struct smatch_state *state;
2490
2491 links = sm->state->data;
2492
2493 FOR_EACH_PTR(links, tmp) {
2494 if (sm->sym == tmp->sym &&
2495 strcmp(sm->name, tmp->var) == 0)
2496 continue;
2497 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2498 if (!state)
2499 continue;
2500 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2501 } END_FOR_EACH_PTR(tmp);
2502 set_state(link_id, sm->name, sm->sym, &undefined);
2503 }
2504
2505 void register_smatch_extra_links(int id)
2506 {
2507 link_id = id;
2508 }
2509
2510 void register_smatch_extra_late(int id)
2511 {
2512 add_merge_hook(link_id, &merge_link_states);
2513 add_modification_hook(link_id, &match_link_modify);
2514 add_hook(&match_dereferences, DEREF_HOOK);
2515 add_hook(&match_pointer_as_array, OP_HOOK);
2516 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
2517 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2518 add_hook(&match_assign, ASSIGNMENT_HOOK);
2519 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2520 add_hook(&unop_expr, OP_HOOK);
2521 add_hook(&asm_expr, ASM_HOOK);
2522
2523 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
2524 add_member_info_callback(my_id, struct_member_callback);
2525 add_split_return_callback(&returned_struct_members);
2526
2527 add_hook(&assume_indexes_are_valid, OP_HOOK);
2528 }
Static analysis for C