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extra: do more simple algebra
[smatch.git] / smatch_extra.c
blobbe72d608620b51417efeb08ede9361046b6472a2
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 static bool in_param_set;
83 static void set_extra_mod_helper(const char *name, struct symbol *sym, struct smatch_state *state)
84 {
85 remove_from_equiv(name, sym);
86 call_extra_mod_hooks(name, sym, state);
87 if ((__in_fake_assign || in_param_set) &&
88 estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
89 return;
90 set_state(SMATCH_EXTRA, name, sym, state);
91 }
92
93 static char *get_pointed_at(const char *name, struct symbol *sym, struct symbol **new_sym)
94 {
95 struct expression *assigned;
96
97 if (name[0] != '*')
98 return NULL;
99 if (strcmp(name + 1, sym->ident->name) != 0)
100 return NULL;
101
102 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
103 if (!assigned)
104 return NULL;
105 assigned = strip_parens(assigned);
106 if (assigned->type != EXPR_PREOP || assigned->op != '&')
107 return NULL;
108
109 return expr_to_var_sym(assigned->unop, new_sym);
110 }
111
112 char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
113 {
114 struct expression *assigned;
115 char *orig_name = NULL;
116 char buf[256];
117 char *ret = NULL;
118 int skip;
119
120 *new_sym = NULL;
121
122 if (!sym || !sym->ident)
123 return NULL;
124
125 ret = get_pointed_at(name, sym, new_sym);
126 if (ret)
127 return ret;
128
129 skip = strlen(sym->ident->name);
130 if (name[skip] != '-' || name[skip + 1] != '>')
131 return NULL;
132 skip += 2;
133
134 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
135 if (!assigned)
136 return NULL;
137 if (assigned->type == EXPR_CALL)
138 return map_call_to_other_name_sym(name, sym, new_sym);
139 if (assigned->type == EXPR_PREOP || assigned->op == '&') {
140
141 orig_name = expr_to_var_sym(assigned, new_sym);
142 if (!orig_name || !*new_sym)
143 goto free;
144
145 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + skip);
146 ret = alloc_string(buf);
147 free_string(orig_name);
148 return ret;
149 }
150
151 if (assigned->type != EXPR_DEREF)
152 goto free;
153
154 orig_name = expr_to_var_sym(assigned, new_sym);
155 if (!orig_name || !*new_sym)
156 goto free;
157
158 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + skip);
159 ret = alloc_string(buf);
160 free_string(orig_name);
161 return ret;
162
163 free:
164 free_string(orig_name);
165 return NULL;
166 }
167
168 void set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
169 {
170 char *new_name;
171 struct symbol *new_sym;
172
173 set_extra_mod_helper(name, sym, state);
174 new_name = get_other_name_sym(name, sym, &new_sym);
175 if (new_name && new_sym)
176 set_extra_mod_helper(new_name, new_sym, state);
177 free_string(new_name);
178 }
179
180 static void clear_array_states(struct expression *array)
181 {
182 struct sm_state *sm;
183
184 sm = get_sm_state_expr(link_id, array);
185 if (sm)
186 match_link_modify(sm, NULL);
187 }
188
189 static void set_extra_array_mod(struct expression *expr, struct smatch_state *state)
190 {
191 struct expression *array;
192 struct var_sym_list *vsl;
193 struct var_sym *vs;
194 char *name;
195 struct symbol *sym;
196
197 array = get_array_base(expr);
198
199 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
200 if (!name || !vsl) {
201 clear_array_states(array);
202 goto free;
203 }
204
205 FOR_EACH_PTR(vsl, vs) {
206 store_link(link_id, vs->var, vs->sym, name, sym);
207 } END_FOR_EACH_PTR(vs);
208
209 call_extra_mod_hooks(name, sym, state);
210 set_state(SMATCH_EXTRA, name, sym, state);
211 free:
212 free_string(name);
213 }
214
215 void set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
216 {
217 struct symbol *sym;
218 char *name;
219
220 if (is_array(expr)) {
221 set_extra_array_mod(expr, state);
222 return;
223 }
224
225 expr = strip_expr(expr);
226 name = expr_to_var_sym(expr, &sym);
227 if (!name || !sym)
228 goto free;
229 set_extra_mod(name, sym, state);
230 free:
231 free_string(name);
232 }
233
234 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
235 {
236 char *new_name;
237 struct symbol *new_sym;
238 struct relation *rel;
239 struct smatch_state *orig_state;
240
241 orig_state = get_state(SMATCH_EXTRA, name, sym);
242
243 /* don't save unknown states if leaving it blank is the same */
244 if (!orig_state && estate_is_unknown(state))
245 return;
246
247 new_name = get_other_name_sym(name, sym, &new_sym);
248 if (new_name && new_sym)
249 set_state(SMATCH_EXTRA, new_name, new_sym, state);
250 free_string(new_name);
251
252 if (!estate_related(orig_state)) {
253 set_state(SMATCH_EXTRA, name, sym, state);
254 return;
255 }
256
257 set_related(state, estate_related(orig_state));
258 FOR_EACH_PTR(estate_related(orig_state), rel) {
259 struct smatch_state *estate;
260
261 if (option_debug_related)
262 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
263 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
264 if (!estate)
265 continue;
266 set_state(SMATCH_EXTRA, rel->name, rel->sym, clone_estate_cast(estate_type(estate), state));
267 } END_FOR_EACH_PTR(rel);
268 }
269
270 void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct smatch_state *state)
271 {
272 struct var_sym *vs;
273
274 FOR_EACH_PTR(vsl, vs) {
275 store_link(link_id, vs->var, vs->sym, name, sym);
276 } END_FOR_EACH_PTR(vs);
277
278 set_extra_nomod(name, sym, state);
279 }
280
281 /*
282 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
283 */
284 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
285 {
286 struct var_sym_list *vsl;
287 struct var_sym *vs;
288 char *name;
289 struct symbol *sym;
290
291 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
292 if (!name || !vsl)
293 goto free;
294 FOR_EACH_PTR(vsl, vs) {
295 store_link(link_id, vs->var, vs->sym, name, sym);
296 } END_FOR_EACH_PTR(vs);
297
298 set_extra_nomod(name, sym, state);
299 free:
300 free_string(name);
301 }
302
303 static void set_extra_true_false(const char *name, struct symbol *sym,
304 struct smatch_state *true_state,
305 struct smatch_state *false_state)
306 {
307 char *new_name;
308 struct symbol *new_sym;
309 struct relation *rel;
310 struct smatch_state *orig_state;
311
312 if (!true_state && !false_state)
313 return;
314
315 if (in_warn_on_macro())
316 return;
317
318 new_name = get_other_name_sym(name, sym, &new_sym);
319 if (new_name && new_sym)
320 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
321 free_string(new_name);
322
323 orig_state = get_state(SMATCH_EXTRA, name, sym);
324
325 if (!estate_related(orig_state)) {
326 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
327 return;
328 }
329
330 if (true_state)
331 set_related(true_state, estate_related(orig_state));
332 if (false_state)
333 set_related(false_state, estate_related(orig_state));
334
335 FOR_EACH_PTR(estate_related(orig_state), rel) {
336 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
337 true_state, false_state);
338 } END_FOR_EACH_PTR(rel);
339 }
340
341 static void set_extra_chunk_true_false(struct expression *expr,
342 struct smatch_state *true_state,
343 struct smatch_state *false_state)
344 {
345 struct var_sym_list *vsl;
346 struct var_sym *vs;
347 struct symbol *type;
348 char *name;
349 struct symbol *sym;
350
351 if (in_warn_on_macro())
352 return;
353
354 type = get_type(expr);
355 if (!type)
356 return;
357
358 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
359 if (!name || !vsl)
360 goto free;
361 FOR_EACH_PTR(vsl, vs) {
362 store_link(link_id, vs->var, vs->sym, name, sym);
363 } END_FOR_EACH_PTR(vs);
364
365 set_true_false_states(SMATCH_EXTRA, name, sym,
366 clone_estate(true_state),
367 clone_estate(false_state));
368 free:
369 free_string(name);
370 }
371
372 static void set_extra_expr_true_false(struct expression *expr,
373 struct smatch_state *true_state,
374 struct smatch_state *false_state)
375 {
376 char *name;
377 struct symbol *sym;
378 sval_t sval;
379
380 if (!true_state && !false_state)
381 return;
382
383 if (get_value(expr, &sval))
384 return;
385
386 expr = strip_expr(expr);
387 name = expr_to_var_sym(expr, &sym);
388 if (!name || !sym) {
389 free_string(name);
390 set_extra_chunk_true_false(expr, true_state, false_state);
391 return;
392 }
393 set_extra_true_false(name, sym, true_state, false_state);
394 free_string(name);
395 }
396
397 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
398 {
399 struct expression *iter_var;
400 struct expression *condition;
401 struct sm_state *sm;
402 struct smatch_state *estate;
403 sval_t start;
404
405 condition = strip_expr(loop->iterator_pre_condition);
406 if (!condition)
407 return NULL;
408 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
409 return NULL;
410 if (condition->op != SPECIAL_DECREMENT)
411 return NULL;
412
413 iter_var = condition->unop;
414 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
415 if (!sm)
416 return NULL;
417 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
418 return NULL;
419 start = estate_max(sm->state);
420 if (sval_cmp_val(start, 0) <= 0)
421 return NULL;
422 if (!sval_is_max(start))
423 start.value--;
424
425 if (condition->type == EXPR_PREOP) {
426 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
427 if (estate_has_hard_max(sm->state))
428 estate_set_hard_max(estate);
429 estate_copy_fuzzy_max(estate, sm->state);
430 set_extra_expr_mod(iter_var, estate);
431 }
432 if (condition->type == EXPR_POSTOP) {
433 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
434 if (estate_has_hard_max(sm->state))
435 estate_set_hard_max(estate);
436 estate_copy_fuzzy_max(estate, sm->state);
437 set_extra_expr_mod(iter_var, estate);
438 }
439 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
440 }
441
442 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
443 struct expression *condition)
444 {
445 struct expression *iter_var;
446 struct sm_state *sm;
447 struct smatch_state *estate;
448 sval_t start, end, max;
449
450 iter_var = iter_expr->unop;
451 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
452 if (!sm)
453 return NULL;
454 if (!estate_get_single_value(sm->state, &start))
455 return NULL;
456 if (get_implied_max(condition->right, &end))
457 end = sval_cast(get_type(iter_var), end);
458 else
459 end = sval_type_max(get_type(iter_var));
460
461 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
462 return NULL;
463
464 switch (condition->op) {
465 case SPECIAL_UNSIGNED_LT:
466 case SPECIAL_NOTEQUAL:
467 case '<':
468 if (!sval_is_min(end))
469 end.value--;
470 break;
471 case SPECIAL_UNSIGNED_LTE:
472 case SPECIAL_LTE:
473 break;
474 default:
475 return NULL;
476 }
477 if (sval_cmp(end, start) < 0)
478 return NULL;
479 estate = alloc_estate_range(start, end);
480 if (get_hard_max(condition->right, &max)) {
481 estate_set_hard_max(estate);
482 if (condition->op == '<' ||
483 condition->op == SPECIAL_UNSIGNED_LT ||
484 condition->op == SPECIAL_NOTEQUAL)
485 max.value--;
486 estate_set_fuzzy_max(estate, max);
487 }
488 set_extra_expr_mod(iter_var, estate);
489 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
490 }
491
492 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
493 struct expression *condition)
494 {
495 struct expression *iter_var;
496 struct sm_state *sm;
497 struct smatch_state *estate;
498 sval_t start, end;
499
500 iter_var = iter_expr->unop;
501 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
502 if (!sm)
503 return NULL;
504 if (!estate_get_single_value(sm->state, &start))
505 return NULL;
506 if (!get_implied_min(condition->right, &end))
507 end = sval_type_min(get_type(iter_var));
508 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
509 return NULL;
510
511 switch (condition->op) {
512 case SPECIAL_NOTEQUAL:
513 case '>':
514 if (!sval_is_min(end) && !sval_is_max(end))
515 end.value++;
516 break;
517 case SPECIAL_GTE:
518 break;
519 default:
520 return NULL;
521 }
522 if (sval_cmp(end, start) > 0)
523 return NULL;
524 estate = alloc_estate_range(end, start);
525 estate_set_hard_max(estate);
526 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
527 set_extra_expr_mod(iter_var, estate);
528 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
529 }
530
531 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
532 {
533 struct expression *iter_expr;
534 struct expression *condition;
535
536 if (!loop->iterator_post_statement)
537 return NULL;
538 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
539 return NULL;
540 iter_expr = loop->iterator_post_statement->expression;
541 if (!loop->iterator_pre_condition)
542 return NULL;
543 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
544 return NULL;
545 condition = loop->iterator_pre_condition;
546
547 if (iter_expr->op == SPECIAL_INCREMENT)
548 return handle_canonical_for_inc(iter_expr, condition);
549 if (iter_expr->op == SPECIAL_DECREMENT)
550 return handle_canonical_for_dec(iter_expr, condition);
551 return NULL;
552 }
553
554 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
555 {
556 struct sm_state *ret;
557
558 __push_fake_cur_stree();
559 if (!loop->iterator_post_statement)
560 ret = handle_canonical_while_count_down(loop);
561 else
562 ret = handle_canonical_for_loops(loop);
563 *stree = __pop_fake_cur_stree();
564 return ret;
565 }
566
567 int __iterator_unchanged(struct sm_state *sm)
568 {
569 if (!sm)
570 return 0;
571 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
572 return 1;
573 return 0;
574 }
575
576 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
577 {
578 sval_t after_value;
579
580 /* paranoid checking. prolly not needed */
581 condition = strip_expr(condition);
582 if (!condition)
583 return;
584 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
585 return;
586 if (condition->op != SPECIAL_DECREMENT)
587 return;
588 after_value = estate_min(sm->state);
589 after_value.value--;
590 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
591 }
592
593 void __extra_pre_loop_hook_after(struct sm_state *sm,
594 struct statement *iterator,
595 struct expression *condition)
596 {
597 struct expression *iter_expr;
598 sval_t limit;
599 struct smatch_state *state;
600
601 if (!iterator) {
602 while_count_down_after(sm, condition);
603 return;
604 }
605
606 iter_expr = iterator->expression;
607
608 if (condition->type != EXPR_COMPARE)
609 return;
610 if (iter_expr->op == SPECIAL_INCREMENT) {
611 limit = sval_binop(estate_max(sm->state), '+',
612 sval_type_val(estate_type(sm->state), 1));
613 } else {
614 limit = sval_binop(estate_min(sm->state), '-',
615 sval_type_val(estate_type(sm->state), 1));
616 }
617 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
618 if (iter_expr->op == SPECIAL_INCREMENT)
619 state = alloc_estate_range(estate_min(sm->state), limit);
620 else
621 state = alloc_estate_range(limit, estate_max(sm->state));
622 } else {
623 state = alloc_estate_sval(limit);
624 }
625 if (!estate_has_hard_max(sm->state)) {
626 estate_clear_hard_max(state);
627 }
628 if (estate_has_fuzzy_max(sm->state)) {
629 sval_t hmax = estate_get_fuzzy_max(sm->state);
630 sval_t max = estate_max(sm->state);
631
632 if (sval_cmp(hmax, max) != 0)
633 estate_clear_fuzzy_max(state);
634 } else if (!estate_has_fuzzy_max(sm->state)) {
635 estate_clear_fuzzy_max(state);
636 }
637
638 set_extra_mod(sm->name, sm->sym, state);
639 }
640
641 static struct stree *unmatched_stree;
642 static struct smatch_state *unmatched_state(struct sm_state *sm)
643 {
644 struct smatch_state *state;
645
646 if (unmatched_stree) {
647 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
648 if (state)
649 return state;
650 }
651 if (parent_is_gone_var_sym(sm->name, sm->sym))
652 return alloc_estate_empty();
653 return alloc_estate_whole(estate_type(sm->state));
654 }
655
656 static void clear_the_pointed_at(struct expression *expr)
657 {
658 struct stree *stree;
659 char *name;
660 struct symbol *sym;
661 struct sm_state *tmp;
662
663 name = expr_to_var_sym(expr, &sym);
664 if (!name || !sym)
665 goto free;
666
667 stree = __get_cur_stree();
668 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
669 if (tmp->name[0] != '*')
670 continue;
671 if (tmp->sym != sym)
672 continue;
673 if (strcmp(tmp->name + 1, name) != 0)
674 continue;
675 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
676 } END_FOR_EACH_SM(tmp);
677
678 free:
679 free_string(name);
680 }
681
682 static void match_function_call(struct expression *expr)
683 {
684 struct expression *arg;
685 struct expression *tmp;
686
687 /* if we have the db this is handled in smatch_function_hooks.c */
688 if (!option_no_db)
689 return;
690 if (inlinable(expr->fn))
691 return;
692
693 FOR_EACH_PTR(expr->args, arg) {
694 tmp = strip_expr(arg);
695 if (tmp->type == EXPR_PREOP && tmp->op == '&')
696 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
697 else
698 clear_the_pointed_at(tmp);
699 } END_FOR_EACH_PTR(arg);
700 }
701
702 static int values_fit_type(struct expression *left, struct expression *right)
703 {
704 struct range_list *rl;
705 struct symbol *type;
706
707 type = get_type(left);
708 if (!type)
709 return 0;
710 get_absolute_rl(right, &rl);
711 if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
712 return 0;
713 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
714 return 0;
715 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
716 return 0;
717 return 1;
718 }
719
720 static void save_chunk_info(struct expression *left, struct expression *right)
721 {
722 struct var_sym_list *vsl;
723 struct var_sym *vs;
724 struct expression *add_expr;
725 struct symbol *type;
726 sval_t sval;
727 char *name;
728 struct symbol *sym;
729
730 if (right->type != EXPR_BINOP || right->op != '-')
731 return;
732 if (!get_value(right->left, &sval))
733 return;
734 if (!expr_to_sym(right->right))
735 return;
736
737 add_expr = binop_expression(left, '+', right->right);
738 type = get_type(add_expr);
739 if (!type)
740 return;
741 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
742 if (!name || !vsl)
743 goto free;
744 FOR_EACH_PTR(vsl, vs) {
745 store_link(link_id, vs->var, vs->sym, name, sym);
746 } END_FOR_EACH_PTR(vs);
747
748 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
749 free:
750 free_string(name);
751 }
752
753 static void do_array_assign(struct expression *left, int op, struct expression *right)
754 {
755 struct range_list *rl;
756
757 if (op == '=') {
758 get_absolute_rl(right, &rl);
759 rl = cast_rl(get_type(left), rl);
760 } else {
761 rl = alloc_whole_rl(get_type(left));
762 }
763
764 set_extra_array_mod(left, alloc_estate_rl(rl));
765 }
766
767 static void match_untracked_array(struct expression *call, int param)
768 {
769 struct expression *arg;
770
771 arg = get_argument_from_call_expr(call->args, param);
772 arg = strip_expr(arg);
773
774 clear_array_states(arg);
775 }
776
777 static void match_vanilla_assign(struct expression *left, struct expression *right)
778 {
779 struct range_list *orig_rl = NULL;
780 struct range_list *rl = NULL;
781 struct symbol *right_sym;
782 struct symbol *left_type;
783 struct symbol *right_type;
784 char *right_name = NULL;
785 struct symbol *sym;
786 char *name;
787 sval_t max;
788 struct smatch_state *state;
789 int comparison;
790
791 if (is_struct(left))
792 return;
793
794 save_chunk_info(left, right);
795
796 name = expr_to_var_sym(left, &sym);
797 if (!name) {
798 if (is_array(left))
799 do_array_assign(left, '=', right);
800 return;
801 }
802
803 left_type = get_type(left);
804 right_type = get_type(right);
805
806 right_name = expr_to_var_sym(right, &right_sym);
807
808 if (!__in_fake_assign &&
809 !(right->type == EXPR_PREOP && right->op == '&') &&
810 right_name && right_sym &&
811 values_fit_type(left, right) &&
812 !has_symbol(right, sym)) {
813 set_equiv(left, right);
814 goto free;
815 }
816
817 if (is_pointer(right) && get_address_rl(right, &rl)) {
818 state = alloc_estate_rl(rl);
819 goto done;
820 }
821
822 if (__in_fake_assign) {
823 struct smatch_state *right_state;
824 sval_t sval;
825
826 if (get_value(right, &sval)) {
827 sval = sval_cast(left_type, sval);
828 state = alloc_estate_sval(sval);
829 goto done;
830 }
831
832 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
833 if (right_state) {
834 /* simple assignment */
835 state = clone_estate(right_state);
836 goto done;
837 }
838
839 state = alloc_estate_rl(alloc_whole_rl(left_type));
840 goto done;
841 }
842
843 comparison = get_comparison(left, right);
844 if (comparison) {
845 comparison = flip_comparison(comparison);
846 get_implied_rl(left, &orig_rl);
847 }
848
849 if (get_implied_rl(right, &rl)) {
850 rl = cast_rl(left_type, rl);
851 if (orig_rl)
852 filter_by_comparison(&rl, comparison, orig_rl);
853 state = alloc_estate_rl(rl);
854 if (get_hard_max(right, &max)) {
855 estate_set_hard_max(state);
856 estate_set_fuzzy_max(state, max);
857 }
858 } else {
859 rl = alloc_whole_rl(right_type);
860 rl = cast_rl(left_type, rl);
861 if (orig_rl)
862 filter_by_comparison(&rl, comparison, orig_rl);
863 state = alloc_estate_rl(rl);
864 }
865
866 done:
867 set_extra_mod(name, sym, state);
868 free:
869 free_string(right_name);
870 }
871
872 static int op_remove_assign(int op)
873 {
874 switch (op) {
875 case SPECIAL_ADD_ASSIGN:
876 return '+';
877 case SPECIAL_SUB_ASSIGN:
878 return '-';
879 case SPECIAL_MUL_ASSIGN:
880 return '*';
881 case SPECIAL_DIV_ASSIGN:
882 return '/';
883 case SPECIAL_MOD_ASSIGN:
884 return '%';
885 case SPECIAL_AND_ASSIGN:
886 return '&';
887 case SPECIAL_OR_ASSIGN:
888 return '|';
889 case SPECIAL_XOR_ASSIGN:
890 return '^';
891 case SPECIAL_SHL_ASSIGN:
892 return SPECIAL_LEFTSHIFT;
893 case SPECIAL_SHR_ASSIGN:
894 return SPECIAL_RIGHTSHIFT;
895 default:
896 return op;
897 }
898 }
899
900 static void match_assign(struct expression *expr)
901 {
902 struct range_list *rl = NULL;
903 struct expression *left;
904 struct expression *right;
905 struct expression *binop_expr;
906 struct symbol *left_type;
907 struct symbol *sym;
908 char *name;
909 sval_t left_min, left_max;
910 sval_t right_min, right_max;
911 sval_t res_min, res_max;
912
913 left = strip_expr(expr->left);
914
915 right = strip_parens(expr->right);
916 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
917 right = get_argument_from_call_expr(right->args, 0);
918 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
919 right = strip_parens(right->left);
920
921 if (expr->op == '=' && is_condition(expr->right))
922 return; /* handled in smatch_condition.c */
923 if (expr->op == '=' && right->type == EXPR_CALL)
924 return; /* handled in smatch_function_hooks.c */
925 if (expr->op == '=') {
926 match_vanilla_assign(left, right);
927 return;
928 }
929
930 name = expr_to_var_sym(left, &sym);
931 if (!name)
932 return;
933
934 left_type = get_type(left);
935
936 res_min = sval_type_min(left_type);
937 res_max = sval_type_max(left_type);
938
939 switch (expr->op) {
940 case SPECIAL_ADD_ASSIGN:
941 get_absolute_max(left, &left_max);
942 get_absolute_max(right, &right_max);
943 if (sval_binop_overflows(left_max, '+', sval_cast(left_type, right_max)))
944 break;
945 if (get_implied_min(left, &left_min) &&
946 !sval_is_negative_min(left_min) &&
947 get_implied_min(right, &right_min) &&
948 !sval_is_negative_min(right_min)) {
949 res_min = sval_binop(left_min, '+', right_min);
950 res_min = sval_cast(left_type, res_min);
951 }
952 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
953 break;
954 res_max = sval_binop(left_max, '+', right_max);
955 res_max = sval_cast(left_type, res_max);
956 break;
957 case SPECIAL_SUB_ASSIGN:
958 if (get_implied_max(left, &left_max) &&
959 !sval_is_max(left_max) &&
960 get_implied_min(right, &right_min) &&
961 !sval_is_min(right_min)) {
962 res_max = sval_binop(left_max, '-', right_min);
963 res_max = sval_cast(left_type, res_max);
964 }
965 if (inside_loop())
966 break;
967 if (get_implied_min(left, &left_min) &&
968 !sval_is_min(left_min) &&
969 get_implied_max(right, &right_max) &&
970 !sval_is_max(right_max) &&
971 sval_cmp(left_min, right_max) > 0) {
972 res_min = sval_binop(left_min, '-', right_max);
973 res_min = sval_cast(left_type, res_min);
974 }
975 break;
976 case SPECIAL_AND_ASSIGN:
977 case SPECIAL_MOD_ASSIGN:
978 case SPECIAL_SHL_ASSIGN:
979 case SPECIAL_SHR_ASSIGN:
980 case SPECIAL_OR_ASSIGN:
981 case SPECIAL_XOR_ASSIGN:
982 case SPECIAL_MUL_ASSIGN:
983 case SPECIAL_DIV_ASSIGN:
984 binop_expr = binop_expression(expr->left,
985 op_remove_assign(expr->op),
986 expr->right);
987 if (get_absolute_rl(binop_expr, &rl)) {
988 rl = cast_rl(left_type, rl);
989 set_extra_mod(name, sym, alloc_estate_rl(rl));
990 goto free;
991 }
992 break;
993 }
994 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
995 set_extra_mod(name, sym, alloc_estate_rl(rl));
996 free:
997 free_string(name);
998 }
999
1000 static struct smatch_state *increment_state(struct smatch_state *state)
1001 {
1002 sval_t min = estate_min(state);
1003 sval_t max = estate_max(state);
1004
1005 if (!estate_rl(state))
1006 return NULL;
1007
1008 if (inside_loop())
1009 max = sval_type_max(max.type);
1010
1011 if (!sval_is_min(min) && !sval_is_max(min))
1012 min.value++;
1013 if (!sval_is_min(max) && !sval_is_max(max))
1014 max.value++;
1015 return alloc_estate_range(min, max);
1016 }
1017
1018 static struct smatch_state *decrement_state(struct smatch_state *state)
1019 {
1020 sval_t min = estate_min(state);
1021 sval_t max = estate_max(state);
1022
1023 if (!estate_rl(state))
1024 return NULL;
1025
1026 if (inside_loop())
1027 min = sval_type_min(min.type);
1028
1029 if (!sval_is_min(min) && !sval_is_max(min))
1030 min.value--;
1031 if (!sval_is_min(max) && !sval_is_max(max))
1032 max.value--;
1033 return alloc_estate_range(min, max);
1034 }
1035
1036 static void clear_pointed_at_state(struct expression *expr)
1037 {
1038 struct symbol *type;
1039
1040 /*
1041 * ALERT: This is sort of a mess. If it's is a struct assigment like
1042 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1043 * the same thing for p++ where "p" is a struct. Most modifications
1044 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1045 * use smatch_modification.c because we have to get the ordering right
1046 * or something. So if you have p++ where p is a pointer to a standard
1047 * c type then we handle that here. What a mess.
1048 */
1049
1050 type = get_type(expr);
1051 if (!type || type->type != SYM_PTR)
1052 return;
1053 type = get_real_base_type(type);
1054 if (!type || type->type != SYM_BASETYPE)
1055 return;
1056 set_extra_expr_mod(deref_expression(expr), alloc_estate_whole(type));
1057 }
1058
1059 static void unop_expr(struct expression *expr)
1060 {
1061 struct smatch_state *state;
1062
1063 if (expr->smatch_flags & Handled)
1064 return;
1065
1066 switch (expr->op) {
1067 case SPECIAL_INCREMENT:
1068 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1069 state = increment_state(state);
1070 if (!state)
1071 state = alloc_estate_whole(get_type(expr));
1072 set_extra_expr_mod(expr->unop, state);
1073 clear_pointed_at_state(expr->unop);
1074 break;
1075 case SPECIAL_DECREMENT:
1076 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1077 state = decrement_state(state);
1078 if (!state)
1079 state = alloc_estate_whole(get_type(expr));
1080 set_extra_expr_mod(expr->unop, state);
1081 clear_pointed_at_state(expr->unop);
1082 break;
1083 default:
1084 return;
1085 }
1086 }
1087
1088 static void asm_expr(struct statement *stmt)
1089 {
1090
1091 struct expression *expr;
1092 struct symbol *type;
1093 int state = 0;
1094
1095 FOR_EACH_PTR(stmt->asm_outputs, expr) {
1096 switch (state) {
1097 case 0: /* identifier */
1098 case 1: /* constraint */
1099 state++;
1100 continue;
1101 case 2: /* expression */
1102 state = 0;
1103 type = get_type(strip_expr(expr));
1104 set_extra_expr_mod(expr, alloc_estate_whole(type));
1105 continue;
1106 }
1107 } END_FOR_EACH_PTR(expr);
1108 }
1109
1110 static void check_dereference(struct expression *expr)
1111 {
1112 if (__in_fake_assign)
1113 return;
1114 if (outside_of_function())
1115 return;
1116 if (implied_not_equal(expr, 0))
1117 return;
1118 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1119 }
1120
1121 static void match_dereferences(struct expression *expr)
1122 {
1123 if (expr->type != EXPR_PREOP)
1124 return;
1125 /* it's saying that foo[1] = bar dereferences foo[1] */
1126 if (is_array(expr))
1127 return;
1128 check_dereference(expr->unop);
1129 }
1130
1131 static void match_pointer_as_array(struct expression *expr)
1132 {
1133 if (!is_array(expr))
1134 return;
1135 check_dereference(get_array_base(expr));
1136 }
1137
1138 static void find_dereferences(struct expression *expr)
1139 {
1140 while (expr->type == EXPR_PREOP) {
1141 if (expr->op == '*')
1142 check_dereference(expr->unop);
1143 expr = strip_expr(expr->unop);
1144 }
1145 }
1146
1147 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
1148 {
1149 struct symbol *sym;
1150 char *name;
1151
1152 name = get_variable_from_key(arg, key, &sym);
1153 if (name && sym)
1154 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
1155 free_string(name);
1156
1157 find_dereferences(arg);
1158 }
1159
1160 static sval_t add_one(sval_t sval)
1161 {
1162 sval.value++;
1163 return sval;
1164 }
1165
1166 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1167 {
1168 struct statement *stmt;
1169 struct expression *cond;
1170 struct smatch_state *true_state, *false_state;
1171 sval_t start;
1172 sval_t limit;
1173
1174 /*
1175 * If we're decrementing here then that's a canonical while count down
1176 * so it's handled already. We're only handling loops like:
1177 * i = 0;
1178 * do { ... } while (i++ < 3);
1179 */
1180
1181 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1182 return 0;
1183
1184 stmt = __cur_stmt->parent;
1185 if (!stmt)
1186 return 0;
1187 if (stmt->type == STMT_COMPOUND)
1188 stmt = stmt->parent;
1189 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1190 return 0;
1191
1192 cond = strip_expr(stmt->iterator_post_condition);
1193 if (cond->type != EXPR_COMPARE || cond->op != op)
1194 return 0;
1195 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1196 return 0;
1197
1198 if (!get_implied_value(left->unop, &start))
1199 return 0;
1200 if (!get_implied_value(right, &limit))
1201 return 0;
1202
1203 if (sval_cmp(start, limit) > 0)
1204 return 0;
1205
1206 switch (op) {
1207 case '<':
1208 case SPECIAL_UNSIGNED_LT:
1209 break;
1210 case SPECIAL_LTE:
1211 case SPECIAL_UNSIGNED_LTE:
1212 limit = add_one(limit);
1213 default:
1214 return 0;
1215
1216 }
1217
1218 true_state = alloc_estate_range(add_one(start), limit);
1219 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1220
1221 /* Currently we just discard the false state but when two passes is
1222 * implimented correctly then it will use it.
1223 */
1224
1225 set_extra_expr_true_false(left->unop, true_state, false_state);
1226
1227 return 1;
1228 }
1229
1230 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1231 {
1232 struct range_list *left_orig;
1233 struct range_list *left_true;
1234 struct range_list *left_false;
1235 struct range_list *right_orig;
1236 struct range_list *right_true;
1237 struct range_list *right_false;
1238 struct smatch_state *left_true_state;
1239 struct smatch_state *left_false_state;
1240 struct smatch_state *right_true_state;
1241 struct smatch_state *right_false_state;
1242 sval_t dummy, hard_max;
1243 int left_postop = 0;
1244 int right_postop = 0;
1245
1246 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1247 if (left->type == EXPR_POSTOP) {
1248 left->smatch_flags |= Handled;
1249 left_postop = left->op;
1250 if (handle_postop_inc(left, op, right))
1251 return;
1252 }
1253 left = strip_parens(left->unop);
1254 }
1255 while (left->type == EXPR_ASSIGNMENT)
1256 left = strip_parens(left->left);
1257
1258 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1259 if (right->type == EXPR_POSTOP) {
1260 right->smatch_flags |= Handled;
1261 right_postop = right->op;
1262 }
1263 right = strip_parens(right->unop);
1264 }
1265
1266 get_real_absolute_rl(left, &left_orig);
1267 left_orig = cast_rl(type, left_orig);
1268
1269 get_real_absolute_rl(right, &right_orig);
1270 right_orig = cast_rl(type, right_orig);
1271
1272 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1273
1274 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1275 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1276 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1277 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1278
1279 if (!left_true || !left_false) {
1280 struct range_list *tmp_true, *tmp_false;
1281
1282 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1283 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1284 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1285 if (tmp_true && tmp_false)
1286 __save_imaginary_state(left, tmp_true, tmp_false);
1287 }
1288
1289 if (!right_true || !right_false) {
1290 struct range_list *tmp_true, *tmp_false;
1291
1292 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1293 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1294 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1295 if (tmp_true && tmp_false)
1296 __save_imaginary_state(right, tmp_true, tmp_false);
1297 }
1298
1299 left_true_state = alloc_estate_rl(left_true);
1300 left_false_state = alloc_estate_rl(left_false);
1301 right_true_state = alloc_estate_rl(right_true);
1302 right_false_state = alloc_estate_rl(right_false);
1303
1304 switch (op) {
1305 case '<':
1306 case SPECIAL_UNSIGNED_LT:
1307 case SPECIAL_UNSIGNED_LTE:
1308 case SPECIAL_LTE:
1309 if (get_hard_max(right, &dummy))
1310 estate_set_hard_max(left_true_state);
1311 if (get_hard_max(left, &dummy))
1312 estate_set_hard_max(right_false_state);
1313 break;
1314 case '>':
1315 case SPECIAL_UNSIGNED_GT:
1316 case SPECIAL_UNSIGNED_GTE:
1317 case SPECIAL_GTE:
1318 if (get_hard_max(left, &dummy))
1319 estate_set_hard_max(right_true_state);
1320 if (get_hard_max(right, &dummy))
1321 estate_set_hard_max(left_false_state);
1322 break;
1323 }
1324
1325 switch (op) {
1326 case '<':
1327 case SPECIAL_UNSIGNED_LT:
1328 case SPECIAL_UNSIGNED_LTE:
1329 case SPECIAL_LTE:
1330 if (get_hard_max(right, &hard_max)) {
1331 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1332 hard_max.value--;
1333 estate_set_fuzzy_max(left_true_state, hard_max);
1334 }
1335 if (get_implied_value(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_hard_max(left, &hard_max)) {
1342 if (op == SPECIAL_UNSIGNED_LTE ||
1343 op == SPECIAL_LTE)
1344 hard_max.value--;
1345 estate_set_fuzzy_max(right_false_state, hard_max);
1346 }
1347 if (get_implied_value(left, &hard_max)) {
1348 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1349 hard_max.value++;
1350 estate_set_fuzzy_max(right_true_state, hard_max);
1351 }
1352 break;
1353 case '>':
1354 case SPECIAL_UNSIGNED_GT:
1355 case SPECIAL_UNSIGNED_GTE:
1356 case SPECIAL_GTE:
1357 if (get_hard_max(left, &hard_max)) {
1358 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1359 hard_max.value--;
1360 estate_set_fuzzy_max(right_true_state, hard_max);
1361 }
1362 if (get_implied_value(left, &hard_max)) {
1363 if (op == SPECIAL_UNSIGNED_GTE ||
1364 op == SPECIAL_GTE)
1365 hard_max.value++;
1366 estate_set_fuzzy_max(right_false_state, hard_max);
1367 }
1368 if (get_hard_max(right, &hard_max)) {
1369 if (op == SPECIAL_UNSIGNED_LTE ||
1370 op == SPECIAL_LTE)
1371 hard_max.value--;
1372 estate_set_fuzzy_max(left_false_state, hard_max);
1373 }
1374 if (get_implied_value(right, &hard_max)) {
1375 if (op == '>' ||
1376 op == SPECIAL_UNSIGNED_GT)
1377 hard_max.value++;
1378 estate_set_fuzzy_max(left_true_state, hard_max);
1379 }
1380 break;
1381 case SPECIAL_EQUAL:
1382 if (get_hard_max(left, &hard_max))
1383 estate_set_fuzzy_max(right_true_state, hard_max);
1384 if (get_hard_max(right, &hard_max))
1385 estate_set_fuzzy_max(left_true_state, hard_max);
1386 break;
1387 }
1388
1389 if (get_hard_max(left, &hard_max)) {
1390 estate_set_hard_max(left_true_state);
1391 estate_set_hard_max(left_false_state);
1392 }
1393 if (get_hard_max(right, &hard_max)) {
1394 estate_set_hard_max(right_true_state);
1395 estate_set_hard_max(right_false_state);
1396 }
1397
1398 if (left_postop == SPECIAL_INCREMENT) {
1399 left_true_state = increment_state(left_true_state);
1400 left_false_state = increment_state(left_false_state);
1401 }
1402 if (left_postop == SPECIAL_DECREMENT) {
1403 left_true_state = decrement_state(left_true_state);
1404 left_false_state = decrement_state(left_false_state);
1405 }
1406 if (right_postop == SPECIAL_INCREMENT) {
1407 right_true_state = increment_state(right_true_state);
1408 right_false_state = increment_state(right_false_state);
1409 }
1410 if (right_postop == SPECIAL_DECREMENT) {
1411 right_true_state = decrement_state(right_true_state);
1412 right_false_state = decrement_state(right_false_state);
1413 }
1414
1415 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1416 left_true_state = NULL;
1417 left_false_state = NULL;
1418 }
1419
1420 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1421 right_true_state = NULL;
1422 right_false_state = NULL;
1423 }
1424
1425 set_extra_expr_true_false(left, left_true_state, left_false_state);
1426 set_extra_expr_true_false(right, right_true_state, right_false_state);
1427 }
1428
1429 static int is_simple_math(struct expression *expr)
1430 {
1431 if (!expr)
1432 return 0;
1433 if (expr->type != EXPR_BINOP)
1434 return 0;
1435 switch (expr->op) {
1436 case '+':
1437 case '-':
1438 case '*':
1439 return 1;
1440 }
1441 return 0;
1442 }
1443
1444 static void move_known_values(struct expression **left_p, struct expression **right_p)
1445 {
1446 struct expression *left = *left_p;
1447 struct expression *right = *right_p;
1448 sval_t sval, dummy;
1449
1450 if (get_implied_value(left, &sval)) {
1451 if (!is_simple_math(right))
1452 return;
1453 if (get_implied_value(right, &dummy))
1454 return;
1455 if (right->op == '*') {
1456 sval_t divisor;
1457
1458 if (!get_value(right->right, &divisor))
1459 return;
1460 if (divisor.value == 0 && sval.value % divisor.value)
1461 return;
1462 *left_p = binop_expression(left, invert_op(right->op), right->right);
1463 *right_p = right->left;
1464 return;
1465 }
1466 if (right->op == '+' && get_value(right->left, &sval)) {
1467 *left_p = binop_expression(left, invert_op(right->op), right->left);
1468 *right_p = right->right;
1469 return;
1470 }
1471 if (get_value(right->right, &sval)) {
1472 *left_p = binop_expression(left, invert_op(right->op), right->right);
1473 *right_p = right->left;
1474 return;
1475 }
1476 return;
1477 }
1478 if (get_implied_value(right, &sval)) {
1479 if (!is_simple_math(left))
1480 return;
1481 if (get_implied_value(left, &dummy))
1482 return;
1483 if (left->op == '*') {
1484 sval_t divisor;
1485
1486 if (!get_value(left->right, &divisor))
1487 return;
1488 if (divisor.value == 0 && sval.value % divisor.value)
1489 return;
1490 *right_p = binop_expression(right, invert_op(left->op), left->right);
1491 *left_p = left->left;
1492 return;
1493 }
1494 if (left->op == '+' && get_value(left->left, &sval)) {
1495 *right_p = binop_expression(right, invert_op(left->op), left->left);
1496 *left_p = left->right;
1497 return;
1498 }
1499
1500 if (get_value(left->right, &sval)) {
1501 *right_p = binop_expression(right, invert_op(left->op), left->right);
1502 *left_p = left->left;
1503 return;
1504 }
1505 return;
1506 }
1507 }
1508
1509 /*
1510 * The reason for do_simple_algebra() is to solve things like:
1511 * if (foo > 66 || foo + bar > 64) {
1512 * "foo" is not really a known variable so it won't be handled by
1513 * move_known_variables() but it's a super common idiom.
1514 *
1515 */
1516 static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
1517 {
1518 struct expression *left = *left_p;
1519 struct expression *right = *right_p;
1520 struct range_list *rl;
1521 sval_t tmp;
1522
1523 if (left->type != EXPR_BINOP || left->op != '+')
1524 return 0;
1525 if (can_integer_overflow(get_type(left), left))
1526 return 0;
1527 if (!get_implied_value(right, &tmp))
1528 return 0;
1529
1530 if (!get_implied_value(left->left, &tmp) &&
1531 get_implied_rl(left->left, &rl) &&
1532 !is_whole_rl(rl)) {
1533 *right_p = binop_expression(right, '-', left->left);
1534 *left_p = left->right;
1535 return 1;
1536 }
1537 if (!get_implied_value(left->right, &tmp) &&
1538 get_implied_rl(left->right, &rl) &&
1539 !is_whole_rl(rl)) {
1540 *right_p = binop_expression(right, '-', left->right);
1541 *left_p = left->left;
1542 return 1;
1543 }
1544
1545 return 0;
1546 }
1547
1548 static int match_func_comparison(struct expression *expr)
1549 {
1550 struct expression *left = strip_expr(expr->left);
1551 struct expression *right = strip_expr(expr->right);
1552 sval_t sval;
1553
1554 /*
1555 * fixme: think about this harder. We should always be trying to limit
1556 * the non-call side as well. If we can't determine the limitter does
1557 * that mean we aren't querying the database and are missing important
1558 * information?
1559 */
1560
1561 if (left->type == EXPR_CALL) {
1562 if (get_implied_value(left, &sval)) {
1563 handle_comparison(get_type(expr), left, expr->op, right);
1564 return 1;
1565 }
1566 function_comparison(left, expr->op, right);
1567 return 1;
1568 }
1569
1570 if (right->type == EXPR_CALL) {
1571 if (get_implied_value(right, &sval)) {
1572 handle_comparison(get_type(expr), left, expr->op, right);
1573 return 1;
1574 }
1575 function_comparison(left, expr->op, right);
1576 return 1;
1577 }
1578
1579 return 0;
1580 }
1581
1582 /* Handle conditions like "if (foo + bar < foo) {" */
1583 static int handle_integer_overflow_test(struct expression *expr)
1584 {
1585 struct expression *left, *right;
1586 struct symbol *type;
1587 sval_t left_min, right_min, min, max;
1588
1589 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
1590 return 0;
1591
1592 left = strip_parens(expr->left);
1593 right = strip_parens(expr->right);
1594
1595 if (left->op != '+')
1596 return 0;
1597
1598 type = get_type(expr);
1599 if (!type)
1600 return 0;
1601 if (type_positive_bits(type) == 32) {
1602 max.type = &uint_ctype;
1603 max.uvalue = (unsigned int)-1;
1604 } else if (type_positive_bits(type) == 64) {
1605 max.type = &ulong_ctype;
1606 max.value = (unsigned long long)-1;
1607 } else {
1608 return 0;
1609 }
1610
1611 if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
1612 return 0;
1613
1614 get_absolute_min(left->left, &left_min);
1615 get_absolute_min(left->right, &right_min);
1616 min = sval_binop(left_min, '+', right_min);
1617
1618 set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
1619 return 1;
1620 }
1621
1622 static void match_comparison(struct expression *expr)
1623 {
1624 struct expression *left_orig = strip_parens(expr->left);
1625 struct expression *right_orig = strip_parens(expr->right);
1626 struct expression *left, *right;
1627 struct expression *prev;
1628 struct symbol *type;
1629
1630 if (match_func_comparison(expr))
1631 return;
1632
1633 type = get_type(expr);
1634 if (!type)
1635 type = &llong_ctype;
1636
1637 if (handle_integer_overflow_test(expr))
1638 return;
1639
1640 left = left_orig;
1641 right = right_orig;
1642 move_known_values(&left, &right);
1643 handle_comparison(type, left, expr->op, right);
1644
1645 left = left_orig;
1646 right = right_orig;
1647 if (do_simple_algebra(&left, &right))
1648 handle_comparison(type, left, expr->op, right);
1649
1650 prev = get_assigned_expr(left_orig);
1651 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1652 left = prev;
1653 right = right_orig;
1654 move_known_values(&left, &right);
1655 handle_comparison(type, left, expr->op, right);
1656 }
1657
1658 prev = get_assigned_expr(right_orig);
1659 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1660 left = left_orig;
1661 right = prev;
1662 move_known_values(&left, &right);
1663 handle_comparison(type, left, expr->op, right);
1664 }
1665 }
1666
1667 static sval_t get_high_mask(sval_t known)
1668 {
1669 sval_t ret;
1670 int i;
1671
1672 ret = known;
1673 ret.value = 0;
1674
1675 for (i = type_bits(known.type) - 1; i >= 0; i--) {
1676 if (known.uvalue & (1ULL << i))
1677 ret.uvalue |= (1ULL << i);
1678 else
1679 return ret;
1680
1681 }
1682 return ret;
1683 }
1684
1685 static void handle_AND_condition(struct expression *expr)
1686 {
1687 struct range_list *orig_rl;
1688 struct range_list *true_rl = NULL;
1689 struct range_list *false_rl = NULL;
1690 sval_t known;
1691 int bit;
1692
1693 if (get_implied_value(expr->left, &known)) {
1694 sval_t low_mask = known;
1695 sval_t high_mask;
1696
1697 if (known.value > 0) {
1698 bit = ffsll(known.value) - 1;
1699 low_mask.uvalue = (1ULL << bit) - 1;
1700 get_absolute_rl(expr->right, &orig_rl);
1701 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
1702 }
1703 high_mask = get_high_mask(known);
1704 if (high_mask.value) {
1705 bit = ffsll(high_mask.value) - 1;
1706 low_mask.uvalue = (1ULL << bit) - 1;
1707
1708 get_absolute_rl(expr->left, &orig_rl);
1709 if (sval_is_negative(rl_min(orig_rl)))
1710 orig_rl = remove_range(orig_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
1711 false_rl = remove_range(orig_rl, low_mask, sval_type_max(known.type));
1712 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
1713 false_rl = remove_range(false_rl,
1714 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
1715 sval_type_val(rl_type(false_rl), -1));
1716 }
1717 }
1718 set_extra_expr_true_false(expr->right,
1719 true_rl ? alloc_estate_rl(true_rl) : NULL,
1720 false_rl ? alloc_estate_rl(false_rl) : NULL);
1721
1722 return;
1723 }
1724
1725 if (get_implied_value(expr->right, &known)) {
1726 sval_t low_mask = known;
1727 sval_t high_mask;
1728
1729 if (known.value > 0) {
1730 bit = ffsll(known.value) - 1;
1731 low_mask.uvalue = (1ULL << bit) - 1;
1732 get_absolute_rl(expr->left, &orig_rl);
1733 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
1734 }
1735 high_mask = get_high_mask(known);
1736 if (high_mask.value) {
1737 bit = ffsll(high_mask.value) - 1;
1738 low_mask.uvalue = (1ULL << bit) - 1;
1739
1740 get_absolute_rl(expr->left, &orig_rl);
1741 if (sval_is_negative(rl_min(orig_rl)))
1742 orig_rl = remove_range(orig_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
1743 false_rl = remove_range(orig_rl, low_mask, sval_type_max(known.type));
1744 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
1745 false_rl = remove_range(false_rl,
1746 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
1747 sval_type_val(rl_type(false_rl), -1));
1748 }
1749 }
1750 set_extra_expr_true_false(expr->left,
1751 true_rl ? alloc_estate_rl(true_rl) : NULL,
1752 false_rl ? alloc_estate_rl(false_rl) : NULL);
1753 return;
1754 }
1755 }
1756
1757 static void handle_MOD_condition(struct expression *expr)
1758 {
1759 struct range_list *orig_rl;
1760 struct range_list *true_rl;
1761 struct range_list *false_rl = NULL;
1762 sval_t right;
1763 sval_t zero = {
1764 .value = 0,
1765 };
1766
1767 if (!get_implied_value(expr->right, &right) || right.value == 0)
1768 return;
1769 get_absolute_rl(expr->left, &orig_rl);
1770
1771 zero.type = rl_type(orig_rl);
1772
1773 /* We're basically dorking around the min and max here */
1774 true_rl = remove_range(orig_rl, zero, zero);
1775 if (!sval_is_max(rl_max(true_rl)) &&
1776 !(rl_max(true_rl).value % right.value))
1777 true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));
1778
1779 if (rl_equiv(true_rl, orig_rl))
1780 true_rl = NULL;
1781
1782 if (sval_is_positive(rl_min(orig_rl)) &&
1783 (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
1784 sval_t add;
1785 int i;
1786
1787 add = rl_min(orig_rl);
1788 add.value += right.value - (add.value % right.value);
1789 add.value -= right.value;
1790
1791 for (i = 0; i < 5; i++) {
1792 add.value += right.value;
1793 if (add.value > rl_max(orig_rl).value)
1794 break;
1795 add_range(&false_rl, add, add);
1796 }
1797 } else {
1798 if (rl_min(orig_rl).uvalue != 0 &&
1799 rl_min(orig_rl).uvalue < right.uvalue) {
1800 sval_t chop = right;
1801 chop.value--;
1802 false_rl = remove_range(orig_rl, zero, chop);
1803 }
1804
1805 if (!sval_is_max(rl_max(orig_rl)) &&
1806 (rl_max(orig_rl).value % right.value)) {
1807 sval_t chop = rl_max(orig_rl);
1808 chop.value -= chop.value % right.value;
1809 chop.value++;
1810 if (!false_rl)
1811 false_rl = clone_rl(orig_rl);
1812 false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
1813 }
1814 }
1815
1816 set_extra_expr_true_false(expr->left,
1817 true_rl ? alloc_estate_rl(true_rl) : NULL,
1818 false_rl ? alloc_estate_rl(false_rl) : NULL);
1819 }
1820
1821 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1822 void __extra_match_condition(struct expression *expr)
1823 {
1824 struct smatch_state *pre_state;
1825 struct smatch_state *true_state;
1826 struct smatch_state *false_state;
1827
1828 expr = strip_expr(expr);
1829 switch (expr->type) {
1830 case EXPR_CALL:
1831 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
1832 return;
1833 case EXPR_PREOP:
1834 case EXPR_SYMBOL:
1835 case EXPR_DEREF: {
1836 sval_t zero;
1837
1838 zero = sval_blank(expr);
1839 zero.value = 0;
1840
1841 pre_state = get_extra_state(expr);
1842 true_state = estate_filter_sval(pre_state, zero);
1843 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1844 false_state = alloc_estate_sval(zero);
1845 else
1846 false_state = alloc_estate_empty();
1847 set_extra_expr_true_false(expr, true_state, false_state);
1848 return;
1849 }
1850 case EXPR_COMPARE:
1851 match_comparison(expr);
1852 return;
1853 case EXPR_ASSIGNMENT:
1854 __extra_match_condition(expr->left);
1855 return;
1856 case EXPR_BINOP:
1857 if (expr->op == '&')
1858 handle_AND_condition(expr);
1859 if (expr->op == '%')
1860 handle_MOD_condition(expr);
1861 return;
1862 }
1863 }
1864
1865 static void assume_indexes_are_valid(struct expression *expr)
1866 {
1867 struct expression *array_expr;
1868 int array_size;
1869 struct expression *offset;
1870 struct symbol *offset_type;
1871 struct range_list *rl_before;
1872 struct range_list *rl_after;
1873 struct range_list *filter = NULL;
1874 sval_t size;
1875
1876 expr = strip_expr(expr);
1877 if (!is_array(expr))
1878 return;
1879
1880 offset = get_array_offset(expr);
1881 offset_type = get_type(offset);
1882 if (offset_type && type_signed(offset_type)) {
1883 filter = alloc_rl(sval_type_min(offset_type),
1884 sval_type_val(offset_type, -1));
1885 }
1886
1887 array_expr = get_array_base(expr);
1888 array_size = get_real_array_size(array_expr);
1889 if (array_size > 1) {
1890 size = sval_type_val(offset_type, array_size);
1891 add_range(&filter, size, sval_type_max(offset_type));
1892 }
1893
1894 if (!filter)
1895 return;
1896 get_absolute_rl(offset, &rl_before);
1897 rl_after = rl_filter(rl_before, filter);
1898 if (rl_equiv(rl_before, rl_after))
1899 return;
1900 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1901 }
1902
1903 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1904 int implied_not_equal(struct expression *expr, long long val)
1905 {
1906 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1907 }
1908
1909 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1910 {
1911 struct smatch_state *estate;
1912
1913 estate = get_state(SMATCH_EXTRA, name, sym);
1914 if (!estate)
1915 return 0;
1916 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1917 return 1;
1918 return 0;
1919 }
1920
1921 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1922 {
1923 char buf[256];
1924 char *start;
1925 char *end;
1926 struct smatch_state *state;
1927
1928 strncpy(buf, name, sizeof(buf) - 1);
1929 buf[sizeof(buf) - 1] = '\0';
1930
1931 start = &buf[0];
1932 while (*start == '*') {
1933 start++;
1934 state = get_state(SMATCH_EXTRA, start, sym);
1935 if (!state)
1936 continue;
1937 if (!estate_rl(state))
1938 return 1;
1939 if (estate_min(state).value == 0 &&
1940 estate_max(state).value == 0)
1941 return 1;
1942 }
1943
1944 start = &buf[0];
1945 while (*start == '&')
1946 start++;
1947
1948 while ((end = strrchr(start, '-'))) {
1949 *end = '\0';
1950 state = get_state(SMATCH_EXTRA, start, sym);
1951 if (!state)
1952 continue;
1953 if (estate_min(state).value == 0 &&
1954 estate_max(state).value == 0)
1955 return 1;
1956 }
1957 return 0;
1958 }
1959
1960 int parent_is_null(struct expression *expr)
1961 {
1962 struct symbol *sym;
1963 char *var;
1964 int ret = 0;
1965
1966 expr = strip_expr(expr);
1967 var = expr_to_var_sym(expr, &sym);
1968 if (!var || !sym)
1969 goto free;
1970 ret = parent_is_null_var_sym(var, sym);
1971 free:
1972 free_string(var);
1973 return ret;
1974 }
1975
1976 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
1977 {
1978 *(int *)found = 1;
1979 return 0;
1980 }
1981
1982 static int filter_unused_kzalloc_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
1983 {
1984 sval_t sval;
1985 int found = 0;
1986
1987 /* for function pointers assume everything is used */
1988 if (call->fn->type != EXPR_SYMBOL)
1989 return 0;
1990
1991 /*
1992 * kzalloc() information is treated as special because so there is just
1993 * a lot of stuff initialized to zero and it makes building the database
1994 * take hours and hours.
1995 *
1996 * In theory, we should just remove this line and not pass any unused
1997 * information, but I'm not sure enough that this code works so I want
1998 * to hold off on that for now.
1999 */
2000 if (!estate_get_single_value(sm->state, &sval) || sval.value != 0)
2001 return 0;
2002
2003 run_sql(&param_used_callback, &found,
2004 "select * from call_implies where %s and type = %d and parameter = %d and key = '%s';",
2005 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
2006 if (found)
2007 return 0;
2008
2009 /* If the database is not built yet, then assume everything is used */
2010 run_sql(&param_used_callback, &found,
2011 "select * from call_implies where %s and type = %d;",
2012 get_static_filter(call->fn->symbol), PARAM_USED);
2013 if (!found)
2014 return 0;
2015
2016 return 1;
2017 }
2018
2019 struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
2020 {
2021 struct smatch_state *state;
2022
2023 /*
2024 * Here is the difference between implied value and real absolute, say
2025 * you have:
2026 *
2027 * int a = (u8)x;
2028 *
2029 * Then you know that a is 0-255. That's real absolute. But you don't
2030 * know for sure that it actually goes up to 255. So it's not implied.
2031 * Implied indicates a degree of certainty.
2032 *
2033 * But then say you cap "a" at 8. That means you know it goes up to
2034 * 8. So now the implied value is s32min-8. But you can combine it
2035 * with the real absolute to say that actually it's 0-8.
2036 *
2037 * We are combining it here. But now that I think about it, this is
2038 * probably not the ideal place to combine it because it should proably
2039 * be done earlier. Oh well, this is an improvement on what was there
2040 * before so I'm going to commit this code.
2041 *
2042 */
2043
2044 state = get_real_absolute_state_var_sym(name, sym);
2045 if (!state || !estate_rl(state))
2046 return start;
2047
2048 return rl_intersection(estate_rl(state), start);
2049 }
2050
2051 struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
2052 {
2053 struct smatch_state *state;
2054
2055 state = get_real_absolute_state(expr);
2056 if (!state || !estate_rl(state))
2057 return start;
2058
2059 return rl_intersection(estate_rl(state), start);
2060 }
2061
2062 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2063 {
2064 struct range_list *rl;
2065
2066 if (estate_is_whole(sm->state))
2067 return;
2068 if (filter_unused_kzalloc_info(call, param, printed_name, sm))
2069 return;
2070 rl = estate_rl(sm->state);
2071 rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
2072 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
2073 if (estate_has_fuzzy_max(sm->state))
2074 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
2075 sval_to_str(estate_get_fuzzy_max(sm->state)));
2076 }
2077
2078 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
2079 {
2080 struct symbol *returned_sym;
2081 struct sm_state *sm;
2082 const char *param_name;
2083 char *compare_str;
2084 char buf[256];
2085
2086 returned_sym = expr_to_sym(expr);
2087 if (!returned_sym)
2088 return;
2089
2090 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
2091 if (!estate_rl(sm->state))
2092 continue;
2093 if (returned_sym != sm->sym)
2094 continue;
2095
2096 param_name = get_param_name(sm);
2097 if (!param_name)
2098 continue;
2099 if (strcmp(param_name, "$") == 0)
2100 continue;
2101 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
2102 if (!compare_str && estate_is_whole(sm->state))
2103 continue;
2104 snprintf(buf, sizeof(buf), "%s%s", sm->state->name, compare_str ?: "");
2105
2106 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
2107 -1, param_name, buf);
2108 } END_FOR_EACH_SM(sm);
2109 }
2110
2111 static void db_limited_before(void)
2112 {
2113 unmatched_stree = clone_stree(__get_cur_stree());
2114 }
2115
2116 static void db_limited_after(void)
2117 {
2118 free_stree(&unmatched_stree);
2119 }
2120
2121 static int rl_fits_in_type(struct range_list *rl, struct symbol *type)
2122 {
2123 if (type_bits(rl_type(rl)) <= type_bits(type))
2124 return 1;
2125 if (sval_cmp(rl_max(rl), sval_type_max(type)) > 0)
2126 return 0;
2127 if (sval_is_negative(rl_min(rl)) &&
2128 sval_cmp(rl_min(rl), sval_type_min(type)) < 0)
2129 return 0;
2130 return 1;
2131 }
2132
2133 static int basically_the_same(struct range_list *orig, struct range_list *new)
2134 {
2135 if (rl_equiv(orig, new))
2136 return 1;
2137
2138 /*
2139 * The whole range is essentially the same as 0,4096-27777777777 so
2140 * don't overwrite the implications just to store that.
2141 *
2142 */
2143 if (rl_type(orig)->type == SYM_PTR &&
2144 is_whole_rl(orig) &&
2145 rl_min(new).value == 0 &&
2146 rl_max(new).value == valid_ptr_max)
2147 return 1;
2148 return 0;
2149 }
2150
2151 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
2152 {
2153 struct expression *arg;
2154 char *name;
2155 struct symbol *sym;
2156 struct var_sym_list *vsl = NULL;
2157 struct sm_state *sm;
2158 struct symbol *compare_type, *var_type;
2159 struct range_list *rl;
2160 struct range_list *limit;
2161 struct range_list *new;
2162
2163 while (expr->type == EXPR_ASSIGNMENT)
2164 expr = strip_expr(expr->right);
2165 if (expr->type != EXPR_CALL)
2166 return;
2167
2168 arg = get_argument_from_call_expr(expr->args, param);
2169 if (!arg)
2170 return;
2171
2172 name = get_chunk_from_key(arg, key, &sym, &vsl);
2173 if (!name)
2174 return;
2175 if (op != PARAM_LIMIT && !sym)
2176 goto free;
2177
2178 if (strcmp(key, "$") == 0)
2179 compare_type = get_arg_type(expr->fn, param);
2180 else
2181 compare_type = get_member_type_from_key(arg, key);
2182
2183 sm = get_sm_state(SMATCH_EXTRA, name, sym);
2184 if (sm)
2185 rl = estate_rl(sm->state);
2186 else
2187 rl = alloc_whole_rl(compare_type);
2188
2189 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
2190 goto free;
2191
2192 call_results_to_rl(expr, compare_type, value, &limit);
2193 new = rl_intersection(rl, limit);
2194
2195 var_type = get_member_type_from_key(arg, key);
2196 new = cast_rl(var_type, new);
2197
2198 /* We want to preserve the implications here */
2199 if (sm && basically_the_same(estate_rl(sm->state), new))
2200 __set_sm(sm); /* FIXME: Is this really necessary? */
2201 else {
2202 char *tmp_name;
2203 struct symbol *tmp_sym;
2204
2205 tmp_name = map_long_to_short_name_sym(name, sym, &tmp_sym);
2206 if (tmp_name && tmp_sym) {
2207 free_string(name);
2208 name = tmp_name;
2209 sym = tmp_sym;
2210 }
2211
2212 if (op == PARAM_LIMIT)
2213 set_extra_nomod_vsl(name, sym, vsl, alloc_estate_rl(new));
2214 else
2215 set_extra_mod(name, sym, alloc_estate_rl(new));
2216 }
2217
2218 free:
2219 free_string(name);
2220 }
2221
2222 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
2223 {
2224 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
2225 }
2226
2227 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
2228 {
2229 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
2230 }
2231
2232 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
2233 {
2234 struct expression *arg;
2235 char *name, *tmp_name;
2236 struct symbol *sym, *tmp_sym;
2237 struct symbol *type;
2238 struct smatch_state *state;
2239 struct range_list *new = NULL;
2240 struct range_list *added = NULL;
2241
2242 while (expr->type == EXPR_ASSIGNMENT)
2243 expr = strip_expr(expr->right);
2244 if (expr->type != EXPR_CALL)
2245 return;
2246
2247 arg = get_argument_from_call_expr(expr->args, param);
2248 if (!arg)
2249 return;
2250 type = get_member_type_from_key(arg, key);
2251 name = get_variable_from_key(arg, key, &sym);
2252 if (!name || !sym)
2253 goto free;
2254
2255 state = get_state(SMATCH_EXTRA, name, sym);
2256 if (state)
2257 new = estate_rl(state);
2258
2259 call_results_to_rl(expr, type, value, &added);
2260
2261 if (op == PARAM_SET)
2262 new = added;
2263 else
2264 new = rl_union(new, added);
2265
2266 tmp_name = map_long_to_short_name_sym_nostack(name, sym, &tmp_sym);
2267 if (tmp_name && tmp_sym) {
2268 free_string(name);
2269 name = tmp_name;
2270 sym = tmp_sym;
2271 }
2272 set_extra_mod(name, sym, alloc_estate_rl(new));
2273 free:
2274 free_string(name);
2275 }
2276
2277 static void db_param_add(struct expression *expr, int param, char *key, char *value)
2278 {
2279 in_param_set = true;
2280 db_param_add_set(expr, param, key, value, PARAM_ADD);
2281 in_param_set = false;
2282 }
2283
2284 static void db_param_set(struct expression *expr, int param, char *key, char *value)
2285 {
2286 in_param_set = true;
2287 db_param_add_set(expr, param, key, value, PARAM_SET);
2288 in_param_set = false;
2289 }
2290
2291 static void db_param_value(struct expression *expr, int param, char *key, char *value)
2292 {
2293 struct expression *call;
2294 char *name;
2295 struct symbol *sym;
2296 struct symbol *type;
2297 struct range_list *rl = NULL;
2298
2299 if (param != -1)
2300 return;
2301
2302 call = expr;
2303 while (call->type == EXPR_ASSIGNMENT)
2304 call = strip_expr(call->right);
2305 if (call->type != EXPR_CALL)
2306 return;
2307
2308 type = get_member_type_from_key(expr->left, key);
2309 name = get_variable_from_key(expr->left, key, &sym);
2310 if (!name || !sym)
2311 goto free;
2312
2313 call_results_to_rl(call, type, value, &rl);
2314
2315 set_extra_mod(name, sym, alloc_estate_rl(rl));
2316 free:
2317 free_string(name);
2318 }
2319
2320 static void match_call_info(struct expression *expr)
2321 {
2322 struct smatch_state *state;
2323 struct range_list *rl = NULL;
2324 struct expression *arg;
2325 struct symbol *type;
2326 int i = 0;
2327
2328 FOR_EACH_PTR(expr->args, arg) {
2329 type = get_arg_type(expr->fn, i);
2330
2331 if (get_implied_rl(arg, &rl))
2332 rl = cast_rl(type, rl);
2333 else
2334 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
2335
2336 if (!is_whole_rl(rl)) {
2337 rl = intersect_with_real_abs_expr(arg, rl);
2338 sql_insert_caller_info(expr, PARAM_VALUE, i, "$", show_rl(rl));
2339 }
2340 state = get_state_expr(SMATCH_EXTRA, arg);
2341 if (estate_has_fuzzy_max(state)) {
2342 sql_insert_caller_info(expr, FUZZY_MAX, i, "$",
2343 sval_to_str(estate_get_fuzzy_max(state)));
2344 }
2345 i++;
2346 } END_FOR_EACH_PTR(arg);
2347 }
2348
2349 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2350 {
2351 struct range_list *rl = NULL;
2352 struct smatch_state *state;
2353 struct symbol *type;
2354 char fullname[256];
2355 sval_t dummy;
2356
2357 if (strcmp(key, "*$") == 0)
2358 snprintf(fullname, sizeof(fullname), "*%s", name);
2359 else if (strncmp(key, "$", 1) == 0)
2360 snprintf(fullname, 256, "%s%s", name, key + 1);
2361 else
2362 return;
2363
2364 type = get_member_type_from_key(symbol_expression(sym), key);
2365 str_to_rl(type, value, &rl);
2366 state = alloc_estate_rl(rl);
2367 if (estate_get_single_value(state, &dummy))
2368 estate_set_hard_max(state);
2369 set_state(SMATCH_EXTRA, fullname, sym, state);
2370 }
2371
2372 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2373 {
2374 struct range_list *rl = NULL;
2375 struct smatch_state *state;
2376 struct symbol *type;
2377 char fullname[256];
2378 sval_t max;
2379
2380 if (strcmp(key, "*$") == 0)
2381 snprintf(fullname, sizeof(fullname), "*%s", name);
2382 else if (strncmp(key, "$", 1) == 0)
2383 snprintf(fullname, 256, "%s%s", name, key + 1);
2384 else
2385 return;
2386
2387 state = get_state(SMATCH_EXTRA, fullname, sym);
2388 if (!state)
2389 return;
2390 type = get_member_type_from_key(symbol_expression(sym), key);
2391 str_to_rl(type, value, &rl);
2392 if (!rl_to_sval(rl, &max))
2393 return;
2394 estate_set_fuzzy_max(state, max);
2395 }
2396
2397 struct smatch_state *get_extra_state(struct expression *expr)
2398 {
2399 char *name;
2400 struct symbol *sym;
2401 struct smatch_state *ret = NULL;
2402 struct range_list *rl;
2403
2404 if (is_pointer(expr) && get_address_rl(expr, &rl))
2405 return alloc_estate_rl(rl);
2406
2407 name = expr_to_known_chunk_sym(expr, &sym);
2408 if (!name)
2409 goto free;
2410
2411 ret = get_state(SMATCH_EXTRA, name, sym);
2412 free:
2413 free_string(name);
2414 return ret;
2415 }
2416
2417 void register_smatch_extra(int id)
2418 {
2419 my_id = id;
2420
2421 add_merge_hook(my_id, &merge_estates);
2422 add_unmatched_state_hook(my_id, &unmatched_state);
2423 select_caller_info_hook(set_param_value, PARAM_VALUE);
2424 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
2425 select_return_states_before(&db_limited_before);
2426 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2427 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2428 select_return_states_hook(PARAM_ADD, &db_param_add);
2429 select_return_states_hook(PARAM_SET, &db_param_set);
2430 select_return_states_hook(PARAM_VALUE, &db_param_value);
2431 select_return_states_after(&db_limited_after);
2432 }
2433
2434 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2435 {
2436 struct var_sym_list *links;
2437 struct var_sym *tmp;
2438 struct smatch_state *state;
2439
2440 links = sm->state->data;
2441
2442 FOR_EACH_PTR(links, tmp) {
2443 if (sm->sym == tmp->sym &&
2444 strcmp(sm->name, tmp->var) == 0)
2445 continue;
2446 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2447 if (!state)
2448 continue;
2449 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2450 } END_FOR_EACH_PTR(tmp);
2451 set_state(link_id, sm->name, sm->sym, &undefined);
2452 }
2453
2454 void register_smatch_extra_links(int id)
2455 {
2456 link_id = id;
2457 }
2458
2459 void register_smatch_extra_late(int id)
2460 {
2461 add_merge_hook(link_id, &merge_link_states);
2462 add_modification_hook(link_id, &match_link_modify);
2463 add_hook(&match_dereferences, DEREF_HOOK);
2464 add_hook(&match_pointer_as_array, OP_HOOK);
2465 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
2466 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2467 add_hook(&match_assign, ASSIGNMENT_HOOK);
2468 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2469 add_hook(&unop_expr, OP_HOOK);
2470 add_hook(&asm_expr, ASM_HOOK);
2471 add_untracked_param_hook(&match_untracked_array);
2472
2473 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
2474 add_member_info_callback(my_id, struct_member_callback);
2475 add_split_return_callback(&returned_struct_members);
2476
2477 add_hook(&assume_indexes_are_valid, OP_HOOK);
2478 }
Static analysis for C