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slist, implied: preserve the entire cur_stree in the pool for fake_strees
[smatch.git] / smatch_extra.c
blobed609a4663ba9293c0c968b920f224f3df018465
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 void add_extra_mod_hook(mod_hook *fn)
67 {
68 mod_hook **p = malloc(sizeof(mod_hook *));
69 *p = fn;
70 add_ptr_list(&extra_mod_hooks, p);
71 }
72
73 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
74 {
75 mod_hook **fn;
76
77 FOR_EACH_PTR(extra_mod_hooks, fn) {
78 (*fn)(name, sym, state);
79 } END_FOR_EACH_PTR(fn);
80 }
81
82 struct sm_state *set_extra_mod_helper(const char *name, struct symbol *sym, struct smatch_state *state)
83 {
84 remove_from_equiv(name, sym);
85 call_extra_mod_hooks(name, sym, state);
86 if (__in_fake_assign && estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
87 return NULL;
88 return set_state(SMATCH_EXTRA, name, sym, state);
89 }
90
91 char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
92 {
93 struct expression *assigned;
94 char *orig_name = NULL;
95 char buf[256];
96 char *ret = NULL;
97 int skip;
98
99 *new_sym = NULL;
100
101 if (!sym || !sym->ident)
102 return NULL;
103
104 skip = strlen(sym->ident->name);
105 if (name[skip] != '-' || name[skip + 1] != '>')
106 return NULL;
107 skip += 2;
108
109 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
110 if (!assigned)
111 return NULL;
112 if (assigned->type == EXPR_PREOP || assigned->op == '&') {
113
114 orig_name = expr_to_var_sym(assigned, new_sym);
115 if (!orig_name || !*new_sym)
116 goto free;
117
118 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + skip);
119 ret = alloc_string(buf);
120 free_string(orig_name);
121 return ret;
122 }
123
124 if (assigned->type != EXPR_DEREF)
125 goto free;
126
127 orig_name = expr_to_var_sym(assigned, new_sym);
128 if (!orig_name || !*new_sym)
129 goto free;
130
131 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + skip);
132 ret = alloc_string(buf);
133 free_string(orig_name);
134 return ret;
135
136 free:
137 free_string(orig_name);
138 return NULL;
139 }
140
141 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
142 {
143 char *new_name;
144 struct symbol *new_sym;
145 struct sm_state *sm;
146
147 sm = set_extra_mod_helper(name, sym, state);
148 new_name = get_other_name_sym(name, sym, &new_sym);
149 if (new_name && new_sym)
150 set_extra_mod_helper(new_name, new_sym, state);
151 free_string(new_name);
152 return sm;
153 }
154
155 static void clear_array_states(struct expression *array)
156 {
157 struct sm_state *sm;
158
159 sm = get_sm_state_expr(link_id, array);
160 if (sm)
161 match_link_modify(sm, NULL);
162 }
163
164 static struct sm_state *set_extra_array_mod(struct expression *expr, struct smatch_state *state)
165 {
166 struct expression *array;
167 struct var_sym_list *vsl;
168 struct var_sym *vs;
169 char *name;
170 struct symbol *sym;
171 struct sm_state *ret = NULL;
172
173 array = get_array_base(expr);
174
175 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
176 if (!name || !vsl) {
177 clear_array_states(array);
178 goto free;
179 }
180
181 FOR_EACH_PTR(vsl, vs) {
182 store_link(link_id, vs->var, vs->sym, name, sym);
183 } END_FOR_EACH_PTR(vs);
184
185 call_extra_mod_hooks(name, sym, state);
186 ret = set_state(SMATCH_EXTRA, name, sym, state);
187 free:
188 free_string(name);
189 return ret;
190 }
191
192 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
193 {
194 struct symbol *sym;
195 char *name;
196 struct sm_state *ret = NULL;
197
198 if (is_array(expr))
199 return set_extra_array_mod(expr, state);
200
201 expr = strip_expr(expr);
202 name = expr_to_var_sym(expr, &sym);
203 if (!name || !sym)
204 goto free;
205 ret = set_extra_mod(name, sym, state);
206 free:
207 free_string(name);
208 return ret;
209 }
210
211 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
212 {
213 char *new_name;
214 struct symbol *new_sym;
215 struct relation *rel;
216 struct smatch_state *orig_state;
217
218 orig_state = get_state(SMATCH_EXTRA, name, sym);
219
220 new_name = get_other_name_sym(name, sym, &new_sym);
221 if (new_name && new_sym)
222 set_state(SMATCH_EXTRA, new_name, new_sym, state);
223 free_string(new_name);
224
225 if (!estate_related(orig_state)) {
226 set_state(SMATCH_EXTRA, name, sym, state);
227 return;
228 }
229
230 set_related(state, estate_related(orig_state));
231 FOR_EACH_PTR(estate_related(orig_state), rel) {
232 struct smatch_state *estate;
233
234 if (option_debug_related)
235 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
236 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
237 if (!estate)
238 continue;
239 set_state(SMATCH_EXTRA, rel->name, rel->sym, clone_estate_cast(estate_type(estate), state));
240 } END_FOR_EACH_PTR(rel);
241 }
242
243 void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct smatch_state *state)
244 {
245 struct var_sym *vs;
246
247 FOR_EACH_PTR(vsl, vs) {
248 store_link(link_id, vs->var, vs->sym, name, sym);
249 } END_FOR_EACH_PTR(vs);
250
251 set_extra_nomod(name, sym, state);
252 }
253
254 /*
255 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
256 */
257 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
258 {
259 struct var_sym_list *vsl;
260 struct var_sym *vs;
261 char *name;
262 struct symbol *sym;
263
264 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
265 if (!name || !vsl)
266 goto free;
267 FOR_EACH_PTR(vsl, vs) {
268 store_link(link_id, vs->var, vs->sym, name, sym);
269 } END_FOR_EACH_PTR(vs);
270
271 set_extra_nomod(name, sym, state);
272 free:
273 free_string(name);
274 }
275
276 static void set_extra_true_false(const char *name, struct symbol *sym,
277 struct smatch_state *true_state,
278 struct smatch_state *false_state)
279 {
280 char *new_name;
281 struct symbol *new_sym;
282 struct relation *rel;
283 struct smatch_state *orig_state;
284
285 if (!true_state && !false_state)
286 return;
287
288 if (in_warn_on_macro())
289 return;
290
291 new_name = get_other_name_sym(name, sym, &new_sym);
292 if (new_name && new_sym)
293 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
294 free_string(new_name);
295
296 orig_state = get_state(SMATCH_EXTRA, name, sym);
297
298 if (!estate_related(orig_state)) {
299 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
300 return;
301 }
302
303 if (true_state)
304 set_related(true_state, estate_related(orig_state));
305 if (false_state)
306 set_related(false_state, estate_related(orig_state));
307
308 FOR_EACH_PTR(estate_related(orig_state), rel) {
309 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
310 true_state, false_state);
311 } END_FOR_EACH_PTR(rel);
312 }
313
314 static void set_extra_chunk_true_false(struct expression *expr,
315 struct smatch_state *true_state,
316 struct smatch_state *false_state)
317 {
318 struct var_sym_list *vsl;
319 struct var_sym *vs;
320 struct symbol *type;
321 char *name;
322 struct symbol *sym;
323
324 if (in_warn_on_macro())
325 return;
326
327 type = get_type(expr);
328 if (!type)
329 return;
330
331 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
332 if (!name || !vsl)
333 goto free;
334 FOR_EACH_PTR(vsl, vs) {
335 store_link(link_id, vs->var, vs->sym, name, sym);
336 } END_FOR_EACH_PTR(vs);
337
338 set_true_false_states(SMATCH_EXTRA, name, sym,
339 clone_estate(true_state),
340 clone_estate(false_state));
341 free:
342 free_string(name);
343 }
344
345 static void set_extra_expr_true_false(struct expression *expr,
346 struct smatch_state *true_state,
347 struct smatch_state *false_state)
348 {
349 char *name;
350 struct symbol *sym;
351 sval_t sval;
352
353 if (!true_state && !false_state)
354 return;
355
356 if (get_value(expr, &sval))
357 return;
358
359 expr = strip_expr(expr);
360 name = expr_to_var_sym(expr, &sym);
361 if (!name || !sym) {
362 free_string(name);
363 set_extra_chunk_true_false(expr, true_state, false_state);
364 return;
365 }
366 set_extra_true_false(name, sym, true_state, false_state);
367 free_string(name);
368 }
369
370 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
371 {
372 struct expression *iter_var;
373 struct expression *condition;
374 struct sm_state *sm;
375 struct smatch_state *estate;
376 sval_t start;
377
378 condition = strip_expr(loop->iterator_pre_condition);
379 if (!condition)
380 return NULL;
381 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
382 return NULL;
383 if (condition->op != SPECIAL_DECREMENT)
384 return NULL;
385
386 iter_var = condition->unop;
387 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
388 if (!sm)
389 return NULL;
390 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
391 return NULL;
392 start = estate_max(sm->state);
393 if (sval_cmp_val(start, 0) <= 0)
394 return NULL;
395 if (!sval_is_max(start))
396 start.value--;
397
398 if (condition->type == EXPR_PREOP) {
399 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
400 if (estate_has_hard_max(sm->state))
401 estate_set_hard_max(estate);
402 estate_copy_fuzzy_max(estate, sm->state);
403 set_extra_expr_mod(iter_var, estate);
404 }
405 if (condition->type == EXPR_POSTOP) {
406 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
407 if (estate_has_hard_max(sm->state))
408 estate_set_hard_max(estate);
409 estate_copy_fuzzy_max(estate, sm->state);
410 set_extra_expr_mod(iter_var, estate);
411 }
412 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
413 }
414
415 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
416 struct expression *condition)
417 {
418 struct expression *iter_var;
419 struct sm_state *sm;
420 struct smatch_state *estate;
421 sval_t start, end, max;
422
423 iter_var = iter_expr->unop;
424 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
425 if (!sm)
426 return NULL;
427 if (!estate_get_single_value(sm->state, &start))
428 return NULL;
429 if (get_implied_max(condition->right, &end))
430 end = sval_cast(get_type(iter_var), end);
431 else
432 end = sval_type_max(get_type(iter_var));
433
434 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
435 return NULL;
436
437 switch (condition->op) {
438 case SPECIAL_UNSIGNED_LT:
439 case SPECIAL_NOTEQUAL:
440 case '<':
441 if (!sval_is_min(end))
442 end.value--;
443 break;
444 case SPECIAL_UNSIGNED_LTE:
445 case SPECIAL_LTE:
446 break;
447 default:
448 return NULL;
449 }
450 if (sval_cmp(end, start) < 0)
451 return NULL;
452 estate = alloc_estate_range(start, end);
453 if (get_hard_max(condition->right, &max)) {
454 estate_set_hard_max(estate);
455 if (condition->op == '<' ||
456 condition->op == SPECIAL_UNSIGNED_LT ||
457 condition->op == SPECIAL_NOTEQUAL)
458 max.value--;
459 estate_set_fuzzy_max(estate, max);
460 }
461 set_extra_expr_mod(iter_var, estate);
462 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
463 }
464
465 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
466 struct expression *condition)
467 {
468 struct expression *iter_var;
469 struct sm_state *sm;
470 struct smatch_state *estate;
471 sval_t start, end;
472
473 iter_var = iter_expr->unop;
474 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
475 if (!sm)
476 return NULL;
477 if (!estate_get_single_value(sm->state, &start))
478 return NULL;
479 if (!get_implied_min(condition->right, &end))
480 end = sval_type_min(get_type(iter_var));
481 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
482 return NULL;
483
484 switch (condition->op) {
485 case SPECIAL_NOTEQUAL:
486 case '>':
487 if (!sval_is_min(end) && !sval_is_max(end))
488 end.value++;
489 break;
490 case SPECIAL_GTE:
491 break;
492 default:
493 return NULL;
494 }
495 if (sval_cmp(end, start) > 0)
496 return NULL;
497 estate = alloc_estate_range(end, start);
498 estate_set_hard_max(estate);
499 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
500 set_extra_expr_mod(iter_var, estate);
501 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
502 }
503
504 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
505 {
506 struct expression *iter_expr;
507 struct expression *condition;
508
509 if (!loop->iterator_post_statement)
510 return NULL;
511 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
512 return NULL;
513 iter_expr = loop->iterator_post_statement->expression;
514 if (!loop->iterator_pre_condition)
515 return NULL;
516 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
517 return NULL;
518 condition = loop->iterator_pre_condition;
519
520 if (iter_expr->op == SPECIAL_INCREMENT)
521 return handle_canonical_for_inc(iter_expr, condition);
522 if (iter_expr->op == SPECIAL_DECREMENT)
523 return handle_canonical_for_dec(iter_expr, condition);
524 return NULL;
525 }
526
527 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
528 {
529 struct sm_state *ret;
530
531 __push_fake_cur_stree();
532 if (!loop->iterator_post_statement)
533 ret = handle_canonical_while_count_down(loop);
534 else
535 ret = handle_canonical_for_loops(loop);
536 *stree = __pop_fake_cur_stree();
537 return ret;
538 }
539
540 int __iterator_unchanged(struct sm_state *sm)
541 {
542 if (!sm)
543 return 0;
544 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
545 return 1;
546 return 0;
547 }
548
549 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
550 {
551 sval_t after_value;
552
553 /* paranoid checking. prolly not needed */
554 condition = strip_expr(condition);
555 if (!condition)
556 return;
557 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
558 return;
559 if (condition->op != SPECIAL_DECREMENT)
560 return;
561 after_value = estate_min(sm->state);
562 after_value.value--;
563 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
564 }
565
566 void __extra_pre_loop_hook_after(struct sm_state *sm,
567 struct statement *iterator,
568 struct expression *condition)
569 {
570 struct expression *iter_expr;
571 sval_t limit;
572 struct smatch_state *state;
573
574 if (!iterator) {
575 while_count_down_after(sm, condition);
576 return;
577 }
578
579 iter_expr = iterator->expression;
580
581 if (condition->type != EXPR_COMPARE)
582 return;
583 if (iter_expr->op == SPECIAL_INCREMENT) {
584 limit = sval_binop(estate_max(sm->state), '+',
585 sval_type_val(estate_type(sm->state), 1));
586 } else {
587 limit = sval_binop(estate_min(sm->state), '-',
588 sval_type_val(estate_type(sm->state), 1));
589 }
590 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
591 if (iter_expr->op == SPECIAL_INCREMENT)
592 state = alloc_estate_range(estate_min(sm->state), limit);
593 else
594 state = alloc_estate_range(limit, estate_max(sm->state));
595 } else {
596 state = alloc_estate_sval(limit);
597 }
598 if (!estate_has_hard_max(sm->state)) {
599 estate_clear_hard_max(state);
600 }
601 if (estate_has_fuzzy_max(sm->state)) {
602 sval_t hmax = estate_get_fuzzy_max(sm->state);
603 sval_t max = estate_max(sm->state);
604
605 if (sval_cmp(hmax, max) != 0)
606 estate_clear_fuzzy_max(state);
607 } else if (!estate_has_fuzzy_max(sm->state)) {
608 estate_clear_fuzzy_max(state);
609 }
610
611 set_extra_mod(sm->name, sm->sym, state);
612 }
613
614 static struct stree *unmatched_stree;
615 static struct smatch_state *unmatched_state(struct sm_state *sm)
616 {
617 struct smatch_state *state;
618
619 if (unmatched_stree) {
620 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
621 if (state)
622 return state;
623 }
624 if (parent_is_gone_var_sym(sm->name, sm->sym))
625 return alloc_estate_empty();
626 return alloc_estate_whole(estate_type(sm->state));
627 }
628
629 static void clear_the_pointed_at(struct expression *expr)
630 {
631 struct stree *stree;
632 char *name;
633 struct symbol *sym;
634 struct sm_state *tmp;
635
636 name = expr_to_var_sym(expr, &sym);
637 if (!name || !sym)
638 goto free;
639
640 stree = __get_cur_stree();
641 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
642 if (tmp->name[0] != '*')
643 continue;
644 if (tmp->sym != sym)
645 continue;
646 if (strcmp(tmp->name + 1, name) != 0)
647 continue;
648 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
649 } END_FOR_EACH_SM(tmp);
650
651 free:
652 free_string(name);
653 }
654
655 static void match_function_call(struct expression *expr)
656 {
657 struct expression *arg;
658 struct expression *tmp;
659
660 /* if we have the db this is handled in smatch_function_hooks.c */
661 if (!option_no_db)
662 return;
663 if (inlinable(expr->fn))
664 return;
665
666 FOR_EACH_PTR(expr->args, arg) {
667 tmp = strip_expr(arg);
668 if (tmp->type == EXPR_PREOP && tmp->op == '&')
669 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
670 else
671 clear_the_pointed_at(tmp);
672 } END_FOR_EACH_PTR(arg);
673 }
674
675 static int values_fit_type(struct expression *left, struct expression *right)
676 {
677 struct range_list *rl;
678 struct symbol *type;
679
680 type = get_type(left);
681 if (!type)
682 return 0;
683 get_absolute_rl(right, &rl);
684 if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
685 return 0;
686 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
687 return 0;
688 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
689 return 0;
690 return 1;
691 }
692
693 static void save_chunk_info(struct expression *left, struct expression *right)
694 {
695 struct var_sym_list *vsl;
696 struct var_sym *vs;
697 struct expression *add_expr;
698 struct symbol *type;
699 sval_t sval;
700 char *name;
701 struct symbol *sym;
702
703 if (right->type != EXPR_BINOP || right->op != '-')
704 return;
705 if (!get_value(right->left, &sval))
706 return;
707 if (!expr_to_sym(right->right))
708 return;
709
710 add_expr = binop_expression(left, '+', right->right);
711 type = get_type(add_expr);
712 if (!type)
713 return;
714 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
715 if (!name || !vsl)
716 goto free;
717 FOR_EACH_PTR(vsl, vs) {
718 store_link(link_id, vs->var, vs->sym, name, sym);
719 } END_FOR_EACH_PTR(vs);
720
721 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
722 free:
723 free_string(name);
724 }
725
726 static void do_array_assign(struct expression *left, int op, struct expression *right)
727 {
728 struct range_list *rl;
729
730 if (op == '=') {
731 get_absolute_rl(right, &rl);
732 rl = cast_rl(get_type(left), rl);
733 } else {
734 rl = alloc_whole_rl(get_type(left));
735 }
736
737 set_extra_array_mod(left, alloc_estate_rl(rl));
738 }
739
740 static void match_untracked_array(struct expression *call, int param)
741 {
742 struct expression *arg;
743
744 arg = get_argument_from_call_expr(call->args, param);
745 arg = strip_expr(arg);
746
747 clear_array_states(arg);
748 }
749
750 static void match_vanilla_assign(struct expression *left, struct expression *right)
751 {
752 struct range_list *orig_rl = NULL;
753 struct range_list *rl = NULL;
754 struct symbol *right_sym;
755 struct symbol *left_type;
756 struct symbol *right_type;
757 char *right_name = NULL;
758 struct symbol *sym;
759 char *name;
760 sval_t max;
761 struct smatch_state *state;
762 int comparison;
763
764 if (is_struct(left))
765 return;
766
767 save_chunk_info(left, right);
768
769 name = expr_to_var_sym(left, &sym);
770 if (!name) {
771 if (is_array(left))
772 do_array_assign(left, '=', right);
773 return;
774 }
775
776 left_type = get_type(left);
777 right_type = get_type(right);
778
779 right_name = expr_to_var_sym(right, &right_sym);
780
781 if (!__in_fake_assign &&
782 !(right->type == EXPR_PREOP && right->op == '&') &&
783 right_name && right_sym &&
784 values_fit_type(left, right) &&
785 !has_symbol(right, sym)) {
786 set_equiv(left, right);
787 goto free;
788 }
789
790 if (is_pointer(right) && get_address_rl(right, &rl)) {
791 state = alloc_estate_rl(rl);
792 goto done;
793 }
794
795 if (__in_fake_assign) {
796 struct smatch_state *right_state;
797 sval_t sval;
798
799 if (get_value(right, &sval)) {
800 sval = sval_cast(left_type, sval);
801 state = alloc_estate_sval(sval);
802 goto done;
803 }
804
805 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
806 if (right_state) {
807 /* simple assignment */
808 state = clone_estate(right_state);
809 goto done;
810 }
811
812 state = alloc_estate_rl(alloc_whole_rl(left_type));
813 goto done;
814 }
815
816 comparison = get_comparison(left, right);
817 if (comparison) {
818 comparison = flip_comparison(comparison);
819 get_implied_rl(left, &orig_rl);
820 }
821
822 if (get_implied_rl(right, &rl)) {
823 rl = cast_rl(left_type, rl);
824 if (orig_rl)
825 filter_by_comparison(&rl, comparison, orig_rl);
826 state = alloc_estate_rl(rl);
827 if (get_hard_max(right, &max)) {
828 estate_set_hard_max(state);
829 estate_set_fuzzy_max(state, max);
830 }
831 } else {
832 rl = alloc_whole_rl(right_type);
833 rl = cast_rl(left_type, rl);
834 if (orig_rl)
835 filter_by_comparison(&rl, comparison, orig_rl);
836 state = alloc_estate_rl(rl);
837 }
838
839 done:
840 set_extra_mod(name, sym, state);
841 free:
842 free_string(right_name);
843 }
844
845 static int op_remove_assign(int op)
846 {
847 switch (op) {
848 case SPECIAL_ADD_ASSIGN:
849 return '+';
850 case SPECIAL_SUB_ASSIGN:
851 return '-';
852 case SPECIAL_MUL_ASSIGN:
853 return '*';
854 case SPECIAL_DIV_ASSIGN:
855 return '/';
856 case SPECIAL_MOD_ASSIGN:
857 return '%';
858 case SPECIAL_AND_ASSIGN:
859 return '&';
860 case SPECIAL_OR_ASSIGN:
861 return '|';
862 case SPECIAL_XOR_ASSIGN:
863 return '^';
864 case SPECIAL_SHL_ASSIGN:
865 return SPECIAL_LEFTSHIFT;
866 case SPECIAL_SHR_ASSIGN:
867 return SPECIAL_RIGHTSHIFT;
868 default:
869 return op;
870 }
871 }
872
873 static void match_assign(struct expression *expr)
874 {
875 struct range_list *rl = NULL;
876 struct expression *left;
877 struct expression *right;
878 struct expression *binop_expr;
879 struct symbol *left_type;
880 struct symbol *right_type;
881 struct symbol *sym;
882 char *name;
883 sval_t left_min, left_max;
884 sval_t right_min, right_max;
885 sval_t res_min, res_max;
886
887 left = strip_expr(expr->left);
888
889 right = strip_parens(expr->right);
890 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
891 right = get_argument_from_call_expr(right->args, 0);
892 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
893 right = strip_parens(right->left);
894
895 if (expr->op == '=' && is_condition(expr->right))
896 return; /* handled in smatch_condition.c */
897 if (expr->op == '=' && right->type == EXPR_CALL)
898 return; /* handled in smatch_function_hooks.c */
899 if (expr->op == '=') {
900 match_vanilla_assign(left, right);
901 return;
902 }
903
904 name = expr_to_var_sym(left, &sym);
905 if (!name)
906 return;
907
908 left_type = get_type(left);
909 right_type = get_type(right);
910
911 res_min = sval_type_min(left_type);
912 res_max = sval_type_max(left_type);
913
914 switch (expr->op) {
915 case SPECIAL_ADD_ASSIGN:
916 get_absolute_max(left, &left_max);
917 get_absolute_max(right, &right_max);
918 if (sval_binop_overflows(left_max, '+', right_max))
919 break;
920 if (get_implied_min(left, &left_min) &&
921 !sval_is_negative_min(left_min) &&
922 get_implied_min(right, &right_min) &&
923 !sval_is_negative_min(right_min)) {
924 res_min = sval_binop(left_min, '+', right_min);
925 res_min = sval_cast(right_type, res_min);
926 }
927 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
928 break;
929 res_max = sval_binop(left_max, '+', right_max);
930 res_max = sval_cast(right_type, res_max);
931 break;
932 case SPECIAL_SUB_ASSIGN:
933 if (get_implied_max(left, &left_max) &&
934 !sval_is_max(left_max) &&
935 get_implied_min(right, &right_min) &&
936 !sval_is_min(right_min)) {
937 res_max = sval_binop(left_max, '-', right_min);
938 res_max = sval_cast(right_type, res_max);
939 }
940 if (inside_loop())
941 break;
942 if (get_implied_min(left, &left_min) &&
943 !sval_is_min(left_min) &&
944 get_implied_max(right, &right_max) &&
945 !sval_is_max(right_max)) {
946 res_min = sval_binop(left_min, '-', right_max);
947 res_min = sval_cast(right_type, res_min);
948 }
949 break;
950 case SPECIAL_AND_ASSIGN:
951 case SPECIAL_MOD_ASSIGN:
952 case SPECIAL_SHL_ASSIGN:
953 case SPECIAL_SHR_ASSIGN:
954 case SPECIAL_OR_ASSIGN:
955 case SPECIAL_XOR_ASSIGN:
956 case SPECIAL_MUL_ASSIGN:
957 case SPECIAL_DIV_ASSIGN:
958 binop_expr = binop_expression(expr->left,
959 op_remove_assign(expr->op),
960 expr->right);
961 if (get_absolute_rl(binop_expr, &rl)) {
962 rl = cast_rl(left_type, rl);
963 set_extra_mod(name, sym, alloc_estate_rl(rl));
964 goto free;
965 }
966 break;
967 }
968 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
969 set_extra_mod(name, sym, alloc_estate_rl(rl));
970 free:
971 free_string(name);
972 }
973
974 static struct smatch_state *increment_state(struct smatch_state *state)
975 {
976 sval_t min = estate_min(state);
977 sval_t max = estate_max(state);
978
979 if (!estate_rl(state))
980 return NULL;
981
982 if (inside_loop())
983 max = sval_type_max(max.type);
984
985 if (!sval_is_min(min) && !sval_is_max(min))
986 min.value++;
987 if (!sval_is_min(max) && !sval_is_max(max))
988 max.value++;
989 return alloc_estate_range(min, max);
990 }
991
992 static struct smatch_state *decrement_state(struct smatch_state *state)
993 {
994 sval_t min = estate_min(state);
995 sval_t max = estate_max(state);
996
997 if (!estate_rl(state))
998 return NULL;
999
1000 if (inside_loop())
1001 min = sval_type_min(min.type);
1002
1003 if (!sval_is_min(min) && !sval_is_max(min))
1004 min.value--;
1005 if (!sval_is_min(max) && !sval_is_max(max))
1006 max.value--;
1007 return alloc_estate_range(min, max);
1008 }
1009
1010 static void clear_pointed_at_state(struct expression *expr)
1011 {
1012 struct symbol *type;
1013
1014 /*
1015 * ALERT: This is sort of a mess. If it's is a struct assigment like
1016 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1017 * the same thing for p++ where "p" is a struct. Most modifications
1018 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1019 * use smatch_modification.c because we have to get the ordering right
1020 * or something. So if you have p++ where p is a pointer to a standard
1021 * c type then we handle that here. What a mess.
1022 */
1023
1024 type = get_type(expr);
1025 if (!type || type->type != SYM_PTR)
1026 return;
1027 type = get_real_base_type(type);
1028 if (!type || type->type != SYM_BASETYPE)
1029 return;
1030 set_extra_expr_mod(deref_expression(expr), alloc_estate_whole(type));
1031 }
1032
1033 static void unop_expr(struct expression *expr)
1034 {
1035 struct smatch_state *state;
1036
1037 if (expr->smatch_flags & Handled)
1038 return;
1039
1040 switch (expr->op) {
1041 case SPECIAL_INCREMENT:
1042 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1043 state = increment_state(state);
1044 if (!state)
1045 state = alloc_estate_whole(get_type(expr));
1046 set_extra_expr_mod(expr->unop, state);
1047 clear_pointed_at_state(expr->unop);
1048 break;
1049 case SPECIAL_DECREMENT:
1050 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1051 state = decrement_state(state);
1052 if (!state)
1053 state = alloc_estate_whole(get_type(expr));
1054 set_extra_expr_mod(expr->unop, state);
1055 clear_pointed_at_state(expr->unop);
1056 break;
1057 default:
1058 return;
1059 }
1060 }
1061
1062 static void asm_expr(struct statement *stmt)
1063 {
1064
1065 struct expression *expr;
1066 struct symbol *type;
1067 int state = 0;
1068
1069 FOR_EACH_PTR(stmt->asm_outputs, expr) {
1070 switch (state) {
1071 case 0: /* identifier */
1072 case 1: /* constraint */
1073 state++;
1074 continue;
1075 case 2: /* expression */
1076 state = 0;
1077 type = get_type(strip_expr(expr));
1078 set_extra_expr_mod(expr, alloc_estate_whole(type));
1079 continue;
1080 }
1081 } END_FOR_EACH_PTR(expr);
1082 }
1083
1084 static void check_dereference(struct expression *expr)
1085 {
1086 if (__in_fake_assign)
1087 return;
1088 if (outside_of_function())
1089 return;
1090 if (implied_not_equal(expr, 0))
1091 return;
1092 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1093 }
1094
1095 static void match_dereferences(struct expression *expr)
1096 {
1097 if (expr->type != EXPR_PREOP)
1098 return;
1099 /* it's saying that foo[1] = bar dereferences foo[1] */
1100 if (is_array(expr))
1101 return;
1102 check_dereference(expr->unop);
1103 }
1104
1105 static void match_pointer_as_array(struct expression *expr)
1106 {
1107 if (!is_array(expr))
1108 return;
1109 check_dereference(get_array_base(expr));
1110 }
1111
1112 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
1113 {
1114 struct symbol *sym;
1115 char *name;
1116
1117 name = get_variable_from_key(arg, key, &sym);
1118 if (!name || !sym)
1119 goto free;
1120
1121 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1122
1123 free:
1124 free_string(name);
1125 }
1126
1127 static sval_t add_one(sval_t sval)
1128 {
1129 sval.value++;
1130 return sval;
1131 }
1132
1133 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1134 {
1135 struct statement *stmt;
1136 struct expression *cond;
1137 struct smatch_state *true_state, *false_state;
1138 sval_t start;
1139 sval_t limit;
1140
1141 /*
1142 * If we're decrementing here then that's a canonical while count down
1143 * so it's handled already. We're only handling loops like:
1144 * i = 0;
1145 * do { ... } while (i++ < 3);
1146 */
1147
1148 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1149 return 0;
1150
1151 stmt = __cur_stmt->parent;
1152 if (!stmt)
1153 return 0;
1154 if (stmt->type == STMT_COMPOUND)
1155 stmt = stmt->parent;
1156 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1157 return 0;
1158
1159 cond = strip_expr(stmt->iterator_post_condition);
1160 if (cond->type != EXPR_COMPARE || cond->op != op)
1161 return 0;
1162 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1163 return 0;
1164
1165 if (!get_implied_value(left->unop, &start))
1166 return 0;
1167 if (!get_implied_value(right, &limit))
1168 return 0;
1169
1170 if (sval_cmp(start, limit) > 0)
1171 return 0;
1172
1173 switch (op) {
1174 case '<':
1175 case SPECIAL_UNSIGNED_LT:
1176 break;
1177 case SPECIAL_LTE:
1178 case SPECIAL_UNSIGNED_LTE:
1179 limit = add_one(limit);
1180 default:
1181 return 0;
1182
1183 }
1184
1185 true_state = alloc_estate_range(add_one(start), limit);
1186 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1187
1188 /* Currently we just discard the false state but when two passes is
1189 * implimented correctly then it will use it.
1190 */
1191
1192 set_extra_expr_true_false(left->unop, true_state, false_state);
1193
1194 return 1;
1195 }
1196
1197 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1198 {
1199 struct range_list *left_orig;
1200 struct range_list *left_true;
1201 struct range_list *left_false;
1202 struct range_list *right_orig;
1203 struct range_list *right_true;
1204 struct range_list *right_false;
1205 struct smatch_state *left_true_state;
1206 struct smatch_state *left_false_state;
1207 struct smatch_state *right_true_state;
1208 struct smatch_state *right_false_state;
1209 sval_t dummy, hard_max;
1210 int left_postop = 0;
1211 int right_postop = 0;
1212
1213 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1214 if (left->type == EXPR_POSTOP) {
1215 left->smatch_flags |= Handled;
1216 left_postop = left->op;
1217 if (handle_postop_inc(left, op, right))
1218 return;
1219 }
1220 left = strip_parens(left->unop);
1221 }
1222 while (left->type == EXPR_ASSIGNMENT)
1223 left = strip_parens(left->left);
1224
1225 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1226 if (right->type == EXPR_POSTOP) {
1227 right->smatch_flags |= Handled;
1228 right_postop = right->op;
1229 }
1230 right = strip_parens(right->unop);
1231 }
1232
1233 get_real_absolute_rl(left, &left_orig);
1234 left_orig = cast_rl(type, left_orig);
1235
1236 get_real_absolute_rl(right, &right_orig);
1237 right_orig = cast_rl(type, right_orig);
1238
1239 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1240
1241 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1242 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1243 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1244 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1245
1246 if (!left_true || !left_false) {
1247 struct range_list *tmp_true, *tmp_false;
1248
1249 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1250 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1251 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1252 if (tmp_true && tmp_false)
1253 __save_imaginary_state(left, tmp_true, tmp_false);
1254 }
1255
1256 if (!right_true || !right_false) {
1257 struct range_list *tmp_true, *tmp_false;
1258
1259 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1260 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1261 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1262 if (tmp_true && tmp_false)
1263 __save_imaginary_state(right, tmp_true, tmp_false);
1264 }
1265
1266 left_true_state = alloc_estate_rl(left_true);
1267 left_false_state = alloc_estate_rl(left_false);
1268 right_true_state = alloc_estate_rl(right_true);
1269 right_false_state = alloc_estate_rl(right_false);
1270
1271 switch (op) {
1272 case '<':
1273 case SPECIAL_UNSIGNED_LT:
1274 case SPECIAL_UNSIGNED_LTE:
1275 case SPECIAL_LTE:
1276 if (get_hard_max(right, &dummy))
1277 estate_set_hard_max(left_true_state);
1278 if (get_hard_max(left, &dummy))
1279 estate_set_hard_max(right_false_state);
1280 break;
1281 case '>':
1282 case SPECIAL_UNSIGNED_GT:
1283 case SPECIAL_UNSIGNED_GTE:
1284 case SPECIAL_GTE:
1285 if (get_hard_max(left, &dummy))
1286 estate_set_hard_max(right_true_state);
1287 if (get_hard_max(right, &dummy))
1288 estate_set_hard_max(left_false_state);
1289 break;
1290 }
1291
1292 switch (op) {
1293 case '<':
1294 case SPECIAL_UNSIGNED_LT:
1295 case SPECIAL_UNSIGNED_LTE:
1296 case SPECIAL_LTE:
1297 if (get_hard_max(right, &hard_max)) {
1298 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1299 hard_max.value--;
1300 estate_set_fuzzy_max(left_true_state, hard_max);
1301 }
1302 if (get_implied_value(right, &hard_max)) {
1303 if (op == SPECIAL_UNSIGNED_LTE ||
1304 op == SPECIAL_LTE)
1305 hard_max.value++;
1306 estate_set_fuzzy_max(left_false_state, hard_max);
1307 }
1308 if (get_hard_max(left, &hard_max)) {
1309 if (op == SPECIAL_UNSIGNED_LTE ||
1310 op == SPECIAL_LTE)
1311 hard_max.value--;
1312 estate_set_fuzzy_max(right_false_state, hard_max);
1313 }
1314 if (get_implied_value(left, &hard_max)) {
1315 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1316 hard_max.value++;
1317 estate_set_fuzzy_max(right_true_state, hard_max);
1318 }
1319 break;
1320 case '>':
1321 case SPECIAL_UNSIGNED_GT:
1322 case SPECIAL_UNSIGNED_GTE:
1323 case SPECIAL_GTE:
1324 if (get_hard_max(left, &hard_max)) {
1325 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1326 hard_max.value--;
1327 estate_set_fuzzy_max(right_true_state, hard_max);
1328 }
1329 if (get_implied_value(left, &hard_max)) {
1330 if (op == SPECIAL_UNSIGNED_GTE ||
1331 op == SPECIAL_GTE)
1332 hard_max.value++;
1333 estate_set_fuzzy_max(right_false_state, hard_max);
1334 }
1335 if (get_hard_max(right, &hard_max)) {
1336 if (op == SPECIAL_UNSIGNED_LTE ||
1337 op == SPECIAL_LTE)
1338 hard_max.value--;
1339 estate_set_fuzzy_max(left_false_state, hard_max);
1340 }
1341 if (get_implied_value(right, &hard_max)) {
1342 if (op == '>' ||
1343 op == SPECIAL_UNSIGNED_GT)
1344 hard_max.value++;
1345 estate_set_fuzzy_max(left_true_state, hard_max);
1346 }
1347 break;
1348 case SPECIAL_EQUAL:
1349 if (get_hard_max(left, &hard_max))
1350 estate_set_fuzzy_max(right_true_state, hard_max);
1351 if (get_hard_max(right, &hard_max))
1352 estate_set_fuzzy_max(left_true_state, hard_max);
1353 break;
1354 }
1355
1356 if (get_hard_max(left, &hard_max)) {
1357 estate_set_hard_max(left_true_state);
1358 estate_set_hard_max(left_false_state);
1359 }
1360 if (get_hard_max(right, &hard_max)) {
1361 estate_set_hard_max(right_true_state);
1362 estate_set_hard_max(right_false_state);
1363 }
1364
1365 if (left_postop == SPECIAL_INCREMENT) {
1366 left_true_state = increment_state(left_true_state);
1367 left_false_state = increment_state(left_false_state);
1368 }
1369 if (left_postop == SPECIAL_DECREMENT) {
1370 left_true_state = decrement_state(left_true_state);
1371 left_false_state = decrement_state(left_false_state);
1372 }
1373 if (right_postop == SPECIAL_INCREMENT) {
1374 right_true_state = increment_state(right_true_state);
1375 right_false_state = increment_state(right_false_state);
1376 }
1377 if (right_postop == SPECIAL_DECREMENT) {
1378 right_true_state = decrement_state(right_true_state);
1379 right_false_state = decrement_state(right_false_state);
1380 }
1381
1382 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1383 left_true_state = NULL;
1384 left_false_state = NULL;
1385 }
1386
1387 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1388 right_true_state = NULL;
1389 right_false_state = NULL;
1390 }
1391
1392 set_extra_expr_true_false(left, left_true_state, left_false_state);
1393 set_extra_expr_true_false(right, right_true_state, right_false_state);
1394 }
1395
1396 static int is_simple_math(struct expression *expr)
1397 {
1398 if (!expr)
1399 return 0;
1400 if (expr->type != EXPR_BINOP)
1401 return 0;
1402 switch (expr->op) {
1403 case '+':
1404 case '-':
1405 case '*':
1406 return 1;
1407 }
1408 return 0;
1409 }
1410
1411 static void move_known_values(struct expression **left_p, struct expression **right_p)
1412 {
1413 struct expression *left = *left_p;
1414 struct expression *right = *right_p;
1415 sval_t sval;
1416
1417 if (get_implied_value(left, &sval)) {
1418 if (!is_simple_math(right))
1419 return;
1420 if (right->op == '*') {
1421 sval_t divisor;
1422
1423 if (!get_value(right->right, &divisor))
1424 return;
1425 if (divisor.value == 0 && sval.value % divisor.value)
1426 return;
1427 *left_p = binop_expression(left, invert_op(right->op), right->right);
1428 *right_p = right->left;
1429 return;
1430 }
1431 if (right->op == '+' && get_value(right->left, &sval)) {
1432 *left_p = binop_expression(left, invert_op(right->op), right->left);
1433 *right_p = right->right;
1434 return;
1435 }
1436 if (get_value(right->right, &sval)) {
1437 *left_p = binop_expression(left, invert_op(right->op), right->right);
1438 *right_p = right->left;
1439 return;
1440 }
1441 return;
1442 }
1443 if (get_implied_value(right, &sval)) {
1444 if (!is_simple_math(left))
1445 return;
1446 if (left->op == '*') {
1447 sval_t divisor;
1448
1449 if (!get_value(left->right, &divisor))
1450 return;
1451 if (divisor.value == 0 && sval.value % divisor.value)
1452 return;
1453 *right_p = binop_expression(right, invert_op(left->op), left->right);
1454 *left_p = left->left;
1455 return;
1456 }
1457 if (left->op == '+' && get_value(left->left, &sval)) {
1458 *right_p = binop_expression(right, invert_op(left->op), left->left);
1459 *left_p = left->right;
1460 return;
1461 }
1462
1463 if (get_value(left->right, &sval)) {
1464 *right_p = binop_expression(right, invert_op(left->op), left->right);
1465 *left_p = left->left;
1466 return;
1467 }
1468 return;
1469 }
1470 }
1471
1472 static int match_func_comparison(struct expression *expr)
1473 {
1474 struct expression *left = strip_expr(expr->left);
1475 struct expression *right = strip_expr(expr->right);
1476 sval_t sval;
1477
1478 /*
1479 * fixme: think about this harder. We should always be trying to limit
1480 * the non-call side as well. If we can't determine the limitter does
1481 * that mean we aren't querying the database and are missing important
1482 * information?
1483 */
1484
1485 if (left->type == EXPR_CALL) {
1486 if (get_implied_value(left, &sval)) {
1487 handle_comparison(get_type(expr), left, expr->op, right);
1488 return 1;
1489 }
1490 function_comparison(left, expr->op, right);
1491 return 1;
1492 }
1493
1494 if (right->type == EXPR_CALL) {
1495 if (get_implied_value(right, &sval)) {
1496 handle_comparison(get_type(expr), left, expr->op, right);
1497 return 1;
1498 }
1499 function_comparison(left, expr->op, right);
1500 return 1;
1501 }
1502
1503 return 0;
1504 }
1505
1506 static void match_comparison(struct expression *expr)
1507 {
1508 struct expression *left_orig = strip_parens(expr->left);
1509 struct expression *right_orig = strip_parens(expr->right);
1510 struct expression *left, *right;
1511 struct expression *prev;
1512 struct symbol *type;
1513
1514 if (match_func_comparison(expr))
1515 return;
1516
1517 type = get_type(expr);
1518 if (!type)
1519 type = &llong_ctype;
1520
1521 left = left_orig;
1522 right = right_orig;
1523 move_known_values(&left, &right);
1524 handle_comparison(type, left, expr->op, right);
1525
1526 prev = get_assigned_expr(left_orig);
1527 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1528 left = prev;
1529 right = right_orig;
1530 move_known_values(&left, &right);
1531 handle_comparison(type, left, expr->op, right);
1532 }
1533
1534 prev = get_assigned_expr(right_orig);
1535 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1536 left = left_orig;
1537 right = prev;
1538 move_known_values(&left, &right);
1539 handle_comparison(type, left, expr->op, right);
1540 }
1541 }
1542
1543 static void handle_AND_condition(struct expression *expr)
1544 {
1545 struct range_list *rl = NULL;
1546 sval_t known;
1547 int bit;
1548
1549 if (get_implied_value(expr->left, &known) && known.value > 0) {
1550 bit = ffsll(known.value) - 1;
1551 known.uvalue = 1ULL << bit;
1552 known.value--;
1553 get_absolute_rl(expr->right, &rl);
1554 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1555 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1556 return;
1557 }
1558
1559 if (get_implied_value(expr->right, &known) && known.value > 0) {
1560 bit = ffsll(known.value) - 1;
1561 known.uvalue = 1ULL << bit;
1562 known.value--;
1563 get_absolute_rl(expr->left, &rl);
1564 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1565 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1566 return;
1567 }
1568 }
1569
1570 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1571 void __extra_match_condition(struct expression *expr)
1572 {
1573 struct smatch_state *pre_state;
1574 struct smatch_state *true_state;
1575 struct smatch_state *false_state;
1576
1577 expr = strip_expr(expr);
1578 switch (expr->type) {
1579 case EXPR_CALL:
1580 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1581 return;
1582 case EXPR_PREOP:
1583 case EXPR_SYMBOL:
1584 case EXPR_DEREF: {
1585 sval_t zero;
1586
1587 zero = sval_blank(expr);
1588 zero.value = 0;
1589
1590 pre_state = get_extra_state(expr);
1591 true_state = estate_filter_sval(pre_state, zero);
1592 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1593 false_state = alloc_estate_sval(zero);
1594 else
1595 false_state = alloc_estate_empty();
1596 set_extra_expr_true_false(expr, true_state, false_state);
1597 return;
1598 }
1599 case EXPR_COMPARE:
1600 match_comparison(expr);
1601 return;
1602 case EXPR_ASSIGNMENT:
1603 __extra_match_condition(expr->left);
1604 return;
1605 case EXPR_BINOP:
1606 if (expr->op == '&')
1607 handle_AND_condition(expr);
1608 return;
1609 }
1610 }
1611
1612 static void assume_indexes_are_valid(struct expression *expr)
1613 {
1614 struct expression *array_expr;
1615 int array_size;
1616 struct expression *offset;
1617 struct symbol *offset_type;
1618 struct range_list *rl_before;
1619 struct range_list *rl_after;
1620 struct range_list *filter = NULL;
1621 sval_t size;
1622
1623 expr = strip_expr(expr);
1624 if (!is_array(expr))
1625 return;
1626
1627 offset = get_array_offset(expr);
1628 offset_type = get_type(offset);
1629 if (offset_type && type_signed(offset_type)) {
1630 filter = alloc_rl(sval_type_min(offset_type),
1631 sval_type_val(offset_type, -1));
1632 }
1633
1634 array_expr = get_array_base(expr);
1635 array_size = get_real_array_size(array_expr);
1636 if (array_size > 1) {
1637 size = sval_type_val(offset_type, array_size);
1638 add_range(&filter, size, sval_type_max(offset_type));
1639 }
1640
1641 if (!filter)
1642 return;
1643 get_absolute_rl(offset, &rl_before);
1644 rl_after = rl_filter(rl_before, filter);
1645 if (rl_equiv(rl_before, rl_after))
1646 return;
1647 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1648 }
1649
1650 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1651 int implied_not_equal(struct expression *expr, long long val)
1652 {
1653 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1654 }
1655
1656 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1657 {
1658 struct smatch_state *estate;
1659
1660 estate = get_state(SMATCH_EXTRA, name, sym);
1661 if (!estate)
1662 return 0;
1663 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1664 return 1;
1665 return 0;
1666 }
1667
1668 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1669 {
1670 char buf[256];
1671 char *start;
1672 char *end;
1673 struct smatch_state *state;
1674
1675 strncpy(buf, name, sizeof(buf) - 1);
1676 buf[sizeof(buf) - 1] = '\0';
1677
1678 start = &buf[0];
1679 while (*start == '*') {
1680 start++;
1681 state = get_state(SMATCH_EXTRA, start, sym);
1682 if (!state)
1683 continue;
1684 if (!estate_rl(state))
1685 return 1;
1686 if (estate_min(state).value == 0 &&
1687 estate_max(state).value == 0)
1688 return 1;
1689 }
1690
1691 start = &buf[0];
1692 while (*start == '&')
1693 start++;
1694
1695 while ((end = strrchr(start, '-'))) {
1696 *end = '\0';
1697 state = get_state(SMATCH_EXTRA, start, sym);
1698 if (!state)
1699 continue;
1700 if (estate_min(state).value == 0 &&
1701 estate_max(state).value == 0)
1702 return 1;
1703 }
1704 return 0;
1705 }
1706
1707 int parent_is_null(struct expression *expr)
1708 {
1709 struct symbol *sym;
1710 char *var;
1711 int ret = 0;
1712
1713 expr = strip_expr(expr);
1714 var = expr_to_var_sym(expr, &sym);
1715 if (!var || !sym)
1716 goto free;
1717 ret = parent_is_null_var_sym(var, sym);
1718 free:
1719 free_string(var);
1720 return ret;
1721 }
1722
1723 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
1724 {
1725 *(int *)found = 1;
1726 return 0;
1727 }
1728
1729 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1730 {
1731 sval_t sval;
1732 int found = 0;
1733
1734 /* for function pointers assume everything is used */
1735 if (call->fn->type != EXPR_SYMBOL)
1736 return 0;
1737
1738 /*
1739 * kzalloc() information is treated as special because so there is just
1740 * a lot of stuff initialized to zero and it makes building the database
1741 * take hours and hours.
1742 *
1743 * In theory, we should just remove this line and not pass any unused
1744 * information, but I'm not sure enough that this code works so I want
1745 * to hold off on that for now.
1746 */
1747 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
1748 return 0;
1749
1750 run_sql(&param_used_callback, &found,
1751 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
1752 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
1753 if (found)
1754 return 0;
1755
1756 /* If the database is not built yet, then assume everything is used */
1757 run_sql(&param_used_callback, &found,
1758 "select * from call_implies where %s and type = %d;",
1759 get_static_filter(call->fn->symbol), PARAM_USED);
1760 if (!found)
1761 return 0;
1762
1763 return 1;
1764 }
1765
1766 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1767 {
1768 if (estate_is_whole(sm->state))
1769 return;
1770 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
1771 return;
1772 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, sm->state->name);
1773 if (estate_has_fuzzy_max(sm->state))
1774 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1775 sval_to_str(estate_get_fuzzy_max(sm->state)));
1776 }
1777
1778 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
1779 {
1780 struct symbol *returned_sym;
1781 struct sm_state *sm;
1782 const char *param_name;
1783 char *compare_str;
1784 char buf[256];
1785
1786 returned_sym = expr_to_sym(expr);
1787 if (!returned_sym)
1788 return;
1789
1790 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
1791 if (!estate_rl(sm->state))
1792 continue;
1793 if (returned_sym != sm->sym)
1794 continue;
1795
1796 param_name = get_param_name(sm);
1797 if (!param_name)
1798 continue;
1799 if (strcmp(param_name, "$") == 0)
1800 continue;
1801 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
1802 if (!compare_str && estate_is_whole(sm->state))
1803 continue;
1804 snprintf(buf, sizeof(buf), "%s%s", sm->state->name, compare_str ?: "");
1805
1806 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
1807 -1, param_name, buf);
1808 } END_FOR_EACH_SM(sm);
1809 }
1810
1811 static void db_limited_before(void)
1812 {
1813 unmatched_stree = clone_stree(__get_cur_stree());
1814 }
1815
1816 static void db_limited_after(void)
1817 {
1818 free_stree(&unmatched_stree);
1819 }
1820
1821 static int rl_fits_in_type(struct range_list *rl, struct symbol *type)
1822 {
1823 if (type_bits(rl_type(rl)) <= type_bits(type))
1824 return 1;
1825 if (sval_cmp(rl_max(rl), sval_type_max(type)) > 0)
1826 return 0;
1827 if (sval_is_negative(rl_min(rl)) &&
1828 sval_cmp(rl_min(rl), sval_type_min(type)) < 0)
1829 return 0;
1830 return 1;
1831 }
1832
1833 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
1834 {
1835 struct expression *arg;
1836 char *name;
1837 struct symbol *sym;
1838 struct var_sym_list *vsl = NULL;
1839 struct sm_state *sm;
1840 struct symbol *compare_type, *var_type;
1841 struct range_list *rl;
1842 struct range_list *limit;
1843 struct range_list *new;
1844
1845 while (expr->type == EXPR_ASSIGNMENT)
1846 expr = strip_expr(expr->right);
1847 if (expr->type != EXPR_CALL)
1848 return;
1849
1850 arg = get_argument_from_call_expr(expr->args, param);
1851 if (!arg)
1852 return;
1853
1854 name = get_chunk_from_key(arg, key, &sym, &vsl);
1855 if (!name)
1856 return;
1857 if (op != PARAM_LIMIT && !sym)
1858 goto free;
1859
1860 if (strcmp(key, "$") == 0)
1861 compare_type = get_arg_type(expr->fn, param);
1862 else
1863 compare_type = get_member_type_from_key(arg, key);
1864
1865 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1866 if (sm)
1867 rl = estate_rl(sm->state);
1868 else
1869 rl = alloc_whole_rl(compare_type);
1870
1871 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
1872 goto free;
1873
1874 call_results_to_rl(expr, compare_type, value, &limit);
1875 new = rl_intersection(rl, limit);
1876
1877 var_type = get_member_type_from_key(arg, key);
1878 new = cast_rl(var_type, new);
1879
1880 /* We want to preserve the implications here */
1881 if (sm && rl_equiv(estate_rl(sm->state), new))
1882 __set_sm(sm);
1883 else {
1884 if (op == PARAM_LIMIT)
1885 set_extra_nomod_vsl(name, sym, vsl, alloc_estate_rl(new));
1886 else
1887 set_extra_mod(name, sym, alloc_estate_rl(new));
1888 }
1889
1890 free:
1891 free_string(name);
1892 }
1893
1894 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1895 {
1896 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
1897 }
1898
1899 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1900 {
1901 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
1902 }
1903
1904 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
1905 {
1906 struct expression *arg;
1907 char *name;
1908 struct symbol *sym;
1909 struct symbol *type;
1910 struct smatch_state *state;
1911 struct range_list *new = NULL;
1912 struct range_list *added = NULL;
1913
1914 while (expr->type == EXPR_ASSIGNMENT)
1915 expr = strip_expr(expr->right);
1916 if (expr->type != EXPR_CALL)
1917 return;
1918
1919 arg = get_argument_from_call_expr(expr->args, param);
1920 if (!arg)
1921 return;
1922 type = get_member_type_from_key(arg, key);
1923 name = get_variable_from_key(arg, key, &sym);
1924 if (!name || !sym)
1925 goto free;
1926
1927 state = get_state(SMATCH_EXTRA, name, sym);
1928 if (state)
1929 new = estate_rl(state);
1930
1931 call_results_to_rl(expr, type, value, &added);
1932
1933 if (op == PARAM_SET)
1934 new = added;
1935 else
1936 new = rl_union(new, added);
1937
1938 set_extra_mod(name, sym, alloc_estate_rl(new));
1939 free:
1940 free_string(name);
1941 }
1942
1943 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1944 {
1945 db_param_add_set(expr, param, key, value, PARAM_ADD);
1946 }
1947
1948 static void db_param_set(struct expression *expr, int param, char *key, char *value)
1949 {
1950 db_param_add_set(expr, param, key, value, PARAM_SET);
1951 }
1952
1953 static void db_param_value(struct expression *expr, int param, char *key, char *value)
1954 {
1955 struct expression *call;
1956 char *name;
1957 struct symbol *sym;
1958 struct symbol *type;
1959 struct range_list *rl = NULL;
1960
1961 if (param != -1)
1962 return;
1963
1964 call = expr;
1965 while (call->type == EXPR_ASSIGNMENT)
1966 call = strip_expr(call->right);
1967 if (call->type != EXPR_CALL)
1968 return;
1969
1970 type = get_member_type_from_key(expr->left, key);
1971 name = get_variable_from_key(expr->left, key, &sym);
1972 if (!name || !sym)
1973 goto free;
1974
1975 call_results_to_rl(call, type, value, &rl);
1976
1977 set_extra_mod(name, sym, alloc_estate_rl(rl));
1978 free:
1979 free_string(name);
1980 }
1981
1982 static void match_call_info(struct expression *expr)
1983 {
1984 struct smatch_state *state;
1985 struct range_list *rl = NULL;
1986 struct expression *arg;
1987 struct symbol *type;
1988 int i = 0;
1989
1990 FOR_EACH_PTR(expr->args, arg) {
1991 type = get_arg_type(expr->fn, i);
1992
1993 if (get_implied_rl(arg, &rl))
1994 rl = cast_rl(type, rl);
1995 else
1996 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1997
1998 if (!is_whole_rl(rl))
1999 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
2000 state = get_state_expr(SMATCH_EXTRA, arg);
2001 if (estate_has_fuzzy_max(state)) {
2002 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
2003 sval_to_str(estate_get_fuzzy_max(state)));
2004 }
2005 i++;
2006 } END_FOR_EACH_PTR(arg);
2007 }
2008
2009 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2010 {
2011 struct range_list *rl = NULL;
2012 struct smatch_state *state;
2013 struct symbol *type;
2014 char fullname[256];
2015
2016 if (strcmp(key, "*$") == 0)
2017 snprintf(fullname, sizeof(fullname), "*%s", name);
2018 else if (strncmp(key, "$", 1) == 0)
2019 snprintf(fullname, 256, "%s%s", name, key + 1);
2020 else
2021 return;
2022
2023 type = get_member_type_from_key(symbol_expression(sym), key);
2024 str_to_rl(type, value, &rl);
2025 state = alloc_estate_rl(rl);
2026 set_state(SMATCH_EXTRA, fullname, sym, state);
2027 }
2028
2029 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2030 {
2031 struct range_list *rl = NULL;
2032 struct smatch_state *state;
2033 struct symbol *type;
2034 char fullname[256];
2035 sval_t max;
2036
2037 if (strcmp(key, "*$") == 0)
2038 snprintf(fullname, sizeof(fullname), "*%s", name);
2039 else if (strncmp(key, "$", 1) == 0)
2040 snprintf(fullname, 256, "%s%s", name, key + 1);
2041 else
2042 return;
2043
2044 state = get_state(SMATCH_EXTRA, fullname, sym);
2045 if (!state)
2046 return;
2047 type = get_member_type_from_key(symbol_expression(sym), key);
2048 str_to_rl(type, value, &rl);
2049 if (!rl_to_sval(rl, &max))
2050 return;
2051 estate_set_fuzzy_max(state, max);
2052 }
2053
2054 struct smatch_state *get_extra_state(struct expression *expr)
2055 {
2056 char *name;
2057 struct symbol *sym;
2058 struct smatch_state *ret = NULL;
2059 struct range_list *rl;
2060
2061 if (is_pointer(expr) && get_address_rl(expr, &rl))
2062 return alloc_estate_rl(rl);
2063
2064 name = expr_to_known_chunk_sym(expr, &sym);
2065 if (!name)
2066 goto free;
2067
2068 ret = get_state(SMATCH_EXTRA, name, sym);
2069 free:
2070 free_string(name);
2071 return ret;
2072 }
2073
2074 void register_smatch_extra(int id)
2075 {
2076 my_id = id;
2077
2078 add_merge_hook(my_id, &merge_estates);
2079 add_unmatched_state_hook(my_id, &unmatched_state);
2080 select_caller_info_hook(set_param_value, PARAM_VALUE);
2081 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
2082 select_return_states_before(&db_limited_before);
2083 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2084 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2085 select_return_states_hook(PARAM_ADD, &db_param_add);
2086 select_return_states_hook(PARAM_SET, &db_param_set);
2087 select_return_states_hook(PARAM_VALUE, &db_param_value);
2088 select_return_states_after(&db_limited_after);
2089 }
2090
2091 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2092 {
2093 struct var_sym_list *links;
2094 struct var_sym *tmp;
2095 struct smatch_state *state;
2096
2097 links = sm->state->data;
2098
2099 FOR_EACH_PTR(links, tmp) {
2100 if (sm->sym == tmp->sym &&
2101 strcmp(sm->name, tmp->var) == 0)
2102 continue;
2103 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2104 if (!state)
2105 continue;
2106 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2107 } END_FOR_EACH_PTR(tmp);
2108 set_state(link_id, sm->name, sm->sym, &undefined);
2109 }
2110
2111 void register_smatch_extra_links(int id)
2112 {
2113 link_id = id;
2114 }
2115
2116 void register_smatch_extra_late(int id)
2117 {
2118 add_merge_hook(link_id, &merge_link_states);
2119 add_modification_hook(link_id, &match_link_modify);
2120 add_hook(&match_dereferences, DEREF_HOOK);
2121 add_hook(&match_pointer_as_array, OP_HOOK);
2122 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
2123 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2124 add_hook(&match_assign, ASSIGNMENT_HOOK);
2125 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2126 add_hook(&unop_expr, OP_HOOK);
2127 add_hook(&asm_expr, ASM_HOOK);
2128 add_untracked_param_hook(&match_untracked_array);
2129
2130 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
2131 add_member_info_callback(my_id, struct_member_callback);
2132 add_split_return_callback(&returned_struct_members);
2133
2134 add_hook(&assume_indexes_are_valid, OP_HOOK);
2135 }
Static analysis for C