?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
validation: delete obsolete dev_hold() check
[smatch.git] / smatch_extra.c
blobc2e2735cd5f87bc362504c08da2f7e77494bb189
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 int in_warn_on_macro(void)
44 {
45 struct statement *stmt;
46 char *tmp;
47 char *macro;
48
49 stmt = get_current_statement();
50 if (!stmt)
51 return 0;
52 macro = get_macro_name(stmt->pos);
53 if (!macro)
54 return 0;
55
56 FOR_EACH_PTR(__ignored_macros, tmp) {
57 if (!strcmp(tmp, macro))
58 return 1;
59 } END_FOR_EACH_PTR(tmp);
60 return 0;
61 }
62
63 typedef void (mod_hook)(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state);
64 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
65 static struct void_fn_list *extra_mod_hooks;
66 static struct void_fn_list *extra_nomod_hooks;
67
68 void add_extra_mod_hook(mod_hook *fn)
69 {
70 mod_hook **p = malloc(sizeof(mod_hook *));
71 *p = fn;
72 add_ptr_list(&extra_mod_hooks, p);
73 }
74
75 void add_extra_nomod_hook(mod_hook *fn)
76 {
77 mod_hook **p = malloc(sizeof(mod_hook *));
78 *p = fn;
79 add_ptr_list(&extra_nomod_hooks, p);
80 }
81
82 void call_extra_hooks(struct void_fn_list *hooks, const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
83 {
84 mod_hook **fn;
85
86 FOR_EACH_PTR(hooks, fn) {
87 (*fn)(name, sym, expr, state);
88 } END_FOR_EACH_PTR(fn);
89 }
90
91 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
92 {
93 call_extra_hooks(extra_mod_hooks, name, sym, expr, state);
94 }
95
96 void call_extra_nomod_hooks(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
97 {
98 call_extra_hooks(extra_nomod_hooks, name, sym, expr, state);
99 }
100
101 static void set_union_info(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
102 {
103 struct symbol *type, *tmp, *inner_type, *inner, *new_type;
104 struct expression *deref, *member_expr;
105 struct smatch_state *new;
106 int offset, inner_offset;
107 static bool in_recurse;
108 char *member_name;
109
110 if (__in_fake_assign)
111 return;
112
113 if (in_recurse)
114 return;
115 in_recurse = true;
116
117 if (!expr || expr->type != EXPR_DEREF || !expr->member)
118 goto done;
119 offset = get_member_offset_from_deref(expr);
120 if (offset < 0)
121 goto done;
122
123 deref = strip_expr(expr->deref);
124 type = get_type(deref);
125 if (type_is_ptr(type))
126 type = get_real_base_type(type);
127 if (!type || type->type != SYM_STRUCT)
128 goto done;
129
130 FOR_EACH_PTR(type->symbol_list, tmp) {
131 inner_type = get_real_base_type(tmp);
132 if (!inner_type || inner_type->type != SYM_UNION)
133 continue;
134
135 inner = first_ptr_list((struct ptr_list *)inner_type->symbol_list);
136 if (!inner || !inner->ident)
137 continue;
138
139 inner_offset = get_member_offset(type, inner->ident->name);
140 if (inner_offset < offset)
141 continue;
142 if (inner_offset > offset)
143 goto done;
144
145 FOR_EACH_PTR(inner_type->symbol_list, inner) {
146 struct symbol *tmp_type;
147
148 if (!inner->ident || inner->ident == expr->member)
149 continue;
150 tmp_type = get_real_base_type(inner);
151 if (tmp_type && tmp_type->type == SYM_STRUCT)
152 continue;
153 member_expr = deref;
154 if (tmp->ident)
155 member_expr = member_expression(member_expr, '.', tmp->ident);
156 member_expr = member_expression(member_expr, expr->op, inner->ident);
157 member_name = expr_to_var(member_expr);
158 if (!member_name)
159 continue;
160 new_type = get_real_base_type(inner);
161 new = alloc_estate_rl(cast_rl(new_type, estate_rl(state)));
162 set_extra_mod_helper(member_name, sym, member_expr, new);
163 free_string(member_name);
164 } END_FOR_EACH_PTR(inner);
165 } END_FOR_EACH_PTR(tmp);
166
167 done:
168 in_recurse = false;
169 }
170
171 static void mark_sub_members_gone(const char *name, struct symbol *sym, struct smatch_state *state)
172 {
173 struct sm_state *sm;
174
175 if (__in_fake_assign || __in_fake_var_assign)
176 return;
177
178 if (!estate_type(state) || estate_type(state)->type != SYM_PTR)
179 return;
180 if (!is_noderef_ptr_rl(estate_rl(state)))
181 return;
182
183 FOR_EACH_MY_SM(SMATCH_EXTRA, __get_cur_stree(), sm) {
184 if (sm->sym != sym)
185 continue;
186 if (strcmp(name, sm->name) == 0)
187 continue;
188 if (!is_sub_member(name, sym, sm))
189 continue;
190 set_extra_nomod(sm->name, sm->sym, NULL, alloc_estate_empty());
191 } END_FOR_EACH_SM(sm);
192 }
193
194 static void call_update_mtag_data(struct expression *expr,
195 struct smatch_state *state)
196 {
197 struct expression *faked;
198
199 if (__in_fake_var_assign)
200 return;
201
202 faked = get_faked_expression();
203 if (!faked)
204 goto update;
205 if (faked->type == EXPR_ASSIGNMENT && is_fresh_alloc(faked->right))
206 goto update;
207 return;
208
209 update:
210 update_mtag_data(expr, state);
211 }
212
213 static bool in_param_set;
214 void set_extra_mod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
215 {
216 if (!expr)
217 expr = gen_expression_from_name_sym(name, sym);
218 remove_from_equiv(name, sym);
219 set_union_info(name, sym, expr, state);
220 mark_sub_members_gone(name, sym, state);
221 call_extra_mod_hooks(name, sym, expr, state);
222 call_update_mtag_data(expr, state);
223 if ((__in_fake_assign || in_param_set) &&
224 estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
225 return;
226 set_state(SMATCH_EXTRA, name, sym, state);
227 }
228
229 static void set_extra_nomod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
230 {
231 call_extra_nomod_hooks(name, sym, expr, state);
232 set_state(SMATCH_EXTRA, name, sym, state);
233 }
234
235 static char *get_pointed_at(const char *name, struct symbol *sym, struct symbol **new_sym)
236 {
237 struct expression *assigned;
238
239 /*
240 * Imagine we have an assignment: "foo = &addr;" then the other name
241 * of "*foo" is addr.
242 */
243
244 if (name[0] != '*')
245 return NULL;
246 if (strcmp(name + 1, sym->ident->name) != 0)
247 return NULL;
248
249 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
250 if (!assigned)
251 return NULL;
252 assigned = strip_parens(assigned);
253 if (assigned->type != EXPR_PREOP || assigned->op != '&')
254 return NULL;
255
256 return expr_to_var_sym(assigned->unop, new_sym);
257 }
258
259 char *get_other_name_sym_from_chunk(const char *name, const char *chunk, int len, struct symbol *sym, struct symbol **new_sym)
260 {
261 struct expression *assigned;
262 char *orig_name = NULL;
263 char buf[256];
264 char *ret;
265
266 assigned = get_assigned_expr_name_sym(chunk, sym);
267 if (!assigned)
268 return NULL;
269 if (assigned->type == EXPR_CALL)
270 return map_call_to_other_name_sym(name, sym, new_sym);
271 if (assigned->type == EXPR_PREOP && assigned->op == '&') {
272
273 orig_name = expr_to_var_sym(assigned, new_sym);
274 if (!orig_name || !*new_sym)
275 goto free;
276
277 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + len);
278 ret = alloc_string(buf);
279 free_string(orig_name);
280 return ret;
281 }
282
283 orig_name = expr_to_var_sym(assigned, new_sym);
284 if (!orig_name || !*new_sym)
285 goto free;
286
287 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + len);
288 ret = alloc_string(buf);
289 free_string(orig_name);
290 return ret;
291 free:
292 free_string(orig_name);
293 return NULL;
294 }
295
296 static char *get_long_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
297 {
298 struct expression *orig;
299 struct symbol *orig_sym;
300 char *orig_name, *ret;
301
302 if (!sym || !sym->ident)
303 return NULL;
304
305 orig = get_assigned_expr_name_sym(sym->ident->name, sym);
306 if (orig) {
307 orig_name = expr_to_var_sym(orig, &orig_sym);
308 if (!orig_name)
309 return NULL;
310
311 ret = swap_names(name, sym->ident->name, orig_name);
312 free_string(orig_name);
313 if (ret)
314 *new_sym = orig_sym;
315 return ret;
316 }
317
318 return NULL;
319 }
320
321 char *get_other_name_sym_helper(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
322 {
323 char buf[256];
324 char *ret;
325 int len;
326
327 *new_sym = NULL;
328
329 if (!sym || !sym->ident)
330 return NULL;
331
332 ret = get_pointed_at(name, sym, new_sym);
333 if (ret)
334 return ret;
335
336 ret = map_long_to_short_name_sym(name, sym, new_sym, use_stack);
337 if (ret)
338 return ret;
339
340 len = snprintf(buf, sizeof(buf), "%s", name);
341 if (len >= sizeof(buf) - 2)
342 return NULL;
343
344 while (use_stack && len >= 1) {
345 if (buf[len] == '>' && buf[len - 1] == '-') {
346 len--;
347 buf[len] = '\0';
348 ret = get_other_name_sym_from_chunk(name, buf, len + 2, sym, new_sym);
349 if (ret)
350 return ret;
351 }
352 len--;
353 }
354
355 ret = get_long_name_sym(name, sym, new_sym, use_stack);
356 if (ret)
357 return ret;
358
359 return NULL;
360 }
361
362 char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
363 {
364 return get_other_name_sym_helper(name, sym, new_sym, true);
365 }
366
367 char *get_other_name_sym_nostack(const char *name, struct symbol *sym, struct symbol **new_sym)
368 {
369 return get_other_name_sym_helper(name, sym, new_sym, false);
370 }
371
372 void set_extra_mod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
373 {
374 char *new_name;
375 struct symbol *new_sym;
376
377 set_extra_mod_helper(name, sym, expr, state);
378 new_name = get_other_name_sym_nostack(name, sym, &new_sym);
379 if (new_name && new_sym)
380 set_extra_mod_helper(new_name, new_sym, NULL, state);
381 free_string(new_name);
382 }
383
384 static struct expression *chunk_get_array_base(struct expression *expr)
385 {
386 /*
387 * The problem with is_array() is that it only returns true for things
388 * like foo[1] but not for foo[1].bar.
389 *
390 */
391 expr = strip_expr(expr);
392 while (expr && expr->type == EXPR_DEREF)
393 expr = strip_expr(expr->deref);
394 return get_array_base(expr);
395 }
396
397 static int chunk_has_array(struct expression *expr)
398 {
399 return !!chunk_get_array_base(expr);
400 }
401
402 static void clear_array_states(struct expression *array)
403 {
404 struct sm_state *sm;
405
406 sm = get_sm_state_expr(link_id, array);
407 if (sm)
408 match_link_modify(sm, NULL);
409 }
410
411 static void set_extra_array_mod(struct expression *expr, struct smatch_state *state)
412 {
413 struct expression *array;
414 struct var_sym_list *vsl;
415 struct var_sym *vs;
416 char *name;
417 struct symbol *sym;
418
419 array = chunk_get_array_base(expr);
420
421 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
422 if (!name || !vsl) {
423 clear_array_states(array);
424 goto free;
425 }
426
427 FOR_EACH_PTR(vsl, vs) {
428 store_link(link_id, vs->var, vs->sym, name, sym);
429 } END_FOR_EACH_PTR(vs);
430
431 call_extra_mod_hooks(name, sym, expr, state);
432 set_state(SMATCH_EXTRA, name, sym, state);
433 free:
434 free_string(name);
435 }
436
437 void set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
438 {
439 struct symbol *sym;
440 char *name;
441
442 if (chunk_has_array(expr)) {
443 set_extra_array_mod(expr, state);
444 return;
445 }
446
447 expr = strip_expr(expr);
448 name = expr_to_var_sym(expr, &sym);
449 if (!name || !sym)
450 goto free;
451 set_extra_mod(name, sym, expr, state);
452 free:
453 free_string(name);
454 }
455
456 void set_extra_nomod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
457 {
458 char *new_name;
459 struct symbol *new_sym;
460 struct relation *rel;
461 struct smatch_state *orig_state;
462
463 orig_state = get_state(SMATCH_EXTRA, name, sym);
464
465 /* don't save unknown states if leaving it blank is the same */
466 if (!orig_state && estate_is_unknown(state))
467 return;
468
469 new_name = get_other_name_sym(name, sym, &new_sym);
470 if (new_name && new_sym)
471 set_extra_nomod_helper(new_name, new_sym, expr, state);
472 free_string(new_name);
473
474 if (!estate_related(orig_state)) {
475 set_extra_nomod_helper(name, sym, expr, state);
476 return;
477 }
478
479 set_related(state, estate_related(orig_state));
480 FOR_EACH_PTR(estate_related(orig_state), rel) {
481 struct smatch_state *estate;
482
483 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
484 if (!estate)
485 continue;
486 set_extra_nomod_helper(rel->name, rel->sym, expr, clone_estate_cast(estate_type(estate), state));
487 } END_FOR_EACH_PTR(rel);
488 }
489
490 void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct expression *expr, struct smatch_state *state)
491 {
492 struct var_sym *vs;
493
494 FOR_EACH_PTR(vsl, vs) {
495 store_link(link_id, vs->var, vs->sym, name, sym);
496 } END_FOR_EACH_PTR(vs);
497
498 set_extra_nomod(name, sym, expr, state);
499 }
500
501 /*
502 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
503 */
504 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
505 {
506 struct var_sym_list *vsl;
507 struct var_sym *vs;
508 char *name;
509 struct symbol *sym;
510
511 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
512 if (!name || !vsl)
513 goto free;
514 FOR_EACH_PTR(vsl, vs) {
515 store_link(link_id, vs->var, vs->sym, name, sym);
516 } END_FOR_EACH_PTR(vs);
517
518 set_extra_nomod(name, sym, expr, state);
519 free:
520 free_string(name);
521 }
522
523 static void set_extra_true_false(const char *name, struct symbol *sym,
524 struct smatch_state *true_state,
525 struct smatch_state *false_state)
526 {
527 char *new_name;
528 struct symbol *new_sym;
529 struct relation *rel;
530 struct smatch_state *orig_state;
531
532 if (!true_state && !false_state)
533 return;
534
535 if (in_warn_on_macro())
536 return;
537
538 new_name = get_other_name_sym(name, sym, &new_sym);
539 if (new_name && new_sym)
540 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
541 free_string(new_name);
542
543 orig_state = get_state(SMATCH_EXTRA, name, sym);
544
545 if (!estate_related(orig_state)) {
546 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
547 return;
548 }
549
550 if (true_state)
551 set_related(true_state, estate_related(orig_state));
552 if (false_state)
553 set_related(false_state, estate_related(orig_state));
554
555 FOR_EACH_PTR(estate_related(orig_state), rel) {
556 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
557 true_state, false_state);
558 } END_FOR_EACH_PTR(rel);
559 }
560
561 static void set_extra_chunk_true_false(struct expression *expr,
562 struct smatch_state *true_state,
563 struct smatch_state *false_state)
564 {
565 struct var_sym_list *vsl;
566 struct var_sym *vs;
567 struct symbol *type;
568 char *name;
569 struct symbol *sym;
570
571 if (in_warn_on_macro())
572 return;
573
574 type = get_type(expr);
575 if (!type)
576 return;
577
578 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
579 if (!name || !vsl)
580 goto free;
581 FOR_EACH_PTR(vsl, vs) {
582 store_link(link_id, vs->var, vs->sym, name, sym);
583 } END_FOR_EACH_PTR(vs);
584
585 set_true_false_states(SMATCH_EXTRA, name, sym,
586 clone_estate(true_state),
587 clone_estate(false_state));
588 free:
589 free_string(name);
590 }
591
592 static void set_extra_expr_true_false(struct expression *expr,
593 struct smatch_state *true_state,
594 struct smatch_state *false_state)
595 {
596 char *name;
597 struct symbol *sym;
598 sval_t sval;
599
600 if (!true_state && !false_state)
601 return;
602
603 if (get_value(expr, &sval))
604 return;
605
606 expr = strip_expr(expr);
607 name = expr_to_var_sym(expr, &sym);
608 if (!name || !sym) {
609 free_string(name);
610 set_extra_chunk_true_false(expr, true_state, false_state);
611 return;
612 }
613 set_extra_true_false(name, sym, true_state, false_state);
614 free_string(name);
615 }
616
617 static int get_countdown_info(struct expression *condition, struct expression **unop, int *op, sval_t *right)
618 {
619 struct expression *unop_expr;
620 int comparison;
621 sval_t limit;
622
623 right->type = &int_ctype;
624 right->value = 0;
625
626 condition = strip_expr(condition);
627
628 if (condition->type == EXPR_COMPARE) {
629 comparison = remove_unsigned_from_comparison(condition->op);
630
631 if (comparison != SPECIAL_GTE && comparison != '>')
632 return 0;
633 if (!get_value(condition->right, &limit))
634 return 0;
635
636 unop_expr = condition->left;
637 if (unop_expr->type != EXPR_PREOP && unop_expr->type != EXPR_POSTOP)
638 return 0;
639 if (unop_expr->op != SPECIAL_DECREMENT)
640 return 0;
641
642 *unop = unop_expr;
643 *op = comparison;
644 *right = limit;
645
646 return 1;
647 }
648
649 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
650 return 0;
651 if (condition->op != SPECIAL_DECREMENT)
652 return 0;
653
654 *unop = condition;
655 *op = '>';
656
657 return 1;
658 }
659
660 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
661 {
662 struct expression *iter_var;
663 struct expression *condition, *unop;
664 struct symbol *type;
665 struct sm_state *sm;
666 struct smatch_state *estate;
667 int op;
668 sval_t start, right;
669
670 right.type = &int_ctype;
671 right.value = 0;
672
673 condition = strip_expr(loop->iterator_pre_condition);
674 if (!condition)
675 return NULL;
676
677 if (!get_countdown_info(condition, &unop, &op, &right))
678 return NULL;
679
680 iter_var = unop->unop;
681
682 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
683 if (!sm)
684 return NULL;
685 if (sval_cmp(estate_min(sm->state), right) < 0)
686 return NULL;
687 start = estate_max(sm->state);
688
689 type = get_type(iter_var);
690 right = sval_cast(type, right);
691 start = sval_cast(type, start);
692
693 if (sval_cmp(start, right) <= 0)
694 return NULL;
695 if (!sval_is_max(start))
696 start.value--;
697
698 if (op == SPECIAL_GTE)
699 right.value--;
700
701 if (unop->type == EXPR_PREOP) {
702 right.value++;
703 estate = alloc_estate_range(right, start);
704 if (estate_has_hard_max(sm->state))
705 estate_set_hard_max(estate);
706 estate_copy_fuzzy_max(estate, sm->state);
707 set_extra_expr_mod(iter_var, estate);
708 }
709 if (unop->type == EXPR_POSTOP) {
710 estate = alloc_estate_range(right, start);
711 if (estate_has_hard_max(sm->state))
712 estate_set_hard_max(estate);
713 estate_copy_fuzzy_max(estate, sm->state);
714 set_extra_expr_mod(iter_var, estate);
715 }
716 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
717 }
718
719 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
720 struct expression *condition)
721 {
722 struct expression *iter_var;
723 struct sm_state *sm;
724 struct smatch_state *estate;
725 sval_t start, end, max;
726 bool unknown_end = false;
727
728 iter_var = iter_expr->unop;
729 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
730 if (!sm)
731 return NULL;
732 if (!estate_get_single_value(sm->state, &start))
733 return NULL;
734 if (!get_implied_max(condition->right, &end)) {
735 end = sval_type_max(get_type(condition->right));
736 end = sval_cast(start.type, end);
737 if (sval_is_max(end))
738 unknown_end = true;
739 }
740
741 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
742 return NULL;
743
744 switch (condition->op) {
745 case SPECIAL_UNSIGNED_LT:
746 case SPECIAL_NOTEQUAL:
747 case '<':
748 if (!sval_is_min(end) && !unknown_end)
749 end.value--;
750 break;
751 case SPECIAL_UNSIGNED_LTE:
752 case SPECIAL_LTE:
753 break;
754 default:
755 return NULL;
756 }
757 if (sval_cmp(end, start) < 0)
758 return NULL;
759 end = sval_cast(start.type, end);
760 estate = alloc_estate_range(start, end);
761 if (get_hard_max(condition->right, &max)) {
762 if (!get_macro_name(condition->pos))
763 estate_set_hard_max(estate);
764 if (condition->op == '<' ||
765 condition->op == SPECIAL_UNSIGNED_LT ||
766 condition->op == SPECIAL_NOTEQUAL)
767 max.value--;
768 max = sval_cast(start.type, max);
769 estate_set_fuzzy_max(estate, max);
770 }
771 set_extra_expr_mod(iter_var, estate);
772 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
773 }
774
775 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
776 struct expression *condition)
777 {
778 struct expression *iter_var;
779 struct sm_state *sm;
780 struct smatch_state *estate;
781 sval_t start, end;
782
783 iter_var = iter_expr->unop;
784 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
785 if (!sm)
786 return NULL;
787 if (!estate_get_single_value(sm->state, &start))
788 return NULL;
789 if (!get_implied_min(condition->right, &end))
790 end = sval_type_min(get_type(iter_var));
791 end = sval_cast(estate_type(sm->state), end);
792 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
793 return NULL;
794
795 switch (condition->op) {
796 case SPECIAL_NOTEQUAL:
797 case '>':
798 if (!sval_is_max(end))
799 end.value++;
800 break;
801 case SPECIAL_GTE:
802 break;
803 default:
804 return NULL;
805 }
806 if (sval_cmp(end, start) > 0)
807 return NULL;
808 estate = alloc_estate_range(end, start);
809 estate_set_hard_max(estate);
810 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
811 set_extra_expr_mod(iter_var, estate);
812 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
813 }
814
815 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
816 {
817 struct expression *iter_expr;
818 struct expression *condition;
819
820 if (!loop->iterator_post_statement)
821 return NULL;
822 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
823 return NULL;
824 iter_expr = loop->iterator_post_statement->expression;
825 if (!loop->iterator_pre_condition)
826 return NULL;
827 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
828 return NULL;
829 condition = loop->iterator_pre_condition;
830
831 if (iter_expr->op == SPECIAL_INCREMENT)
832 return handle_canonical_for_inc(iter_expr, condition);
833 if (iter_expr->op == SPECIAL_DECREMENT)
834 return handle_canonical_for_dec(iter_expr, condition);
835 return NULL;
836 }
837
838 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
839 {
840 struct sm_state *ret;
841
842 /*
843 * Canonical loops are a hack. The proper way to handle this is to
844 * use two passes, but unfortunately, doing two passes makes parsing
845 * code twice as slow.
846 *
847 * What we do is we set the inside state here, which overwrites whatever
848 * __extra_match_condition() does. Then we set the outside state in
849 * __extra_pre_loop_hook_after().
850 *
851 */
852 __push_fake_cur_stree();
853 if (!loop->iterator_post_statement)
854 ret = handle_canonical_while_count_down(loop);
855 else
856 ret = handle_canonical_for_loops(loop);
857 *stree = __pop_fake_cur_stree();
858 return ret;
859 }
860
861 int __iterator_unchanged(struct sm_state *sm)
862 {
863 if (!sm)
864 return 0;
865 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
866 return 1;
867 return 0;
868 }
869
870 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
871 {
872 struct expression *unop;
873 int op;
874 sval_t limit, after_value;
875
876 if (!get_countdown_info(condition, &unop, &op, &limit))
877 return;
878 after_value = estate_min(sm->state);
879 after_value.value--;
880 set_extra_mod(sm->name, sm->sym, condition->unop, alloc_estate_sval(after_value));
881 }
882
883 void __extra_pre_loop_hook_after(struct sm_state *sm,
884 struct statement *iterator,
885 struct expression *condition)
886 {
887 struct expression *iter_expr;
888 sval_t limit;
889 struct smatch_state *state;
890 sval_t end;
891
892 if (!iterator) {
893 while_count_down_after(sm, condition);
894 return;
895 }
896
897 iter_expr = iterator->expression;
898
899 if (condition->type != EXPR_COMPARE)
900 return;
901
902 if (iter_expr->op == SPECIAL_INCREMENT) {
903 if (!get_implied_value(condition->right, &end) &&
904 sval_is_max(estate_max(sm->state)))
905 limit = estate_max(sm->state);
906 else
907 limit = sval_binop(estate_max(sm->state), '+',
908 sval_type_val(estate_type(sm->state), 1));
909 } else {
910 limit = sval_binop(estate_min(sm->state), '-',
911 sval_type_val(estate_type(sm->state), 1));
912 }
913 limit = sval_cast(estate_type(sm->state), limit);
914 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
915 if (iter_expr->op == SPECIAL_INCREMENT)
916 state = alloc_estate_range(estate_min(sm->state), limit);
917 else
918 state = alloc_estate_range(limit, estate_max(sm->state));
919 } else {
920 state = alloc_estate_sval(limit);
921 }
922 if (!estate_has_hard_max(sm->state)) {
923 estate_clear_hard_max(state);
924 }
925 if (estate_has_fuzzy_max(sm->state)) {
926 sval_t hmax = estate_get_fuzzy_max(sm->state);
927 sval_t max = estate_max(sm->state);
928
929 if (sval_cmp(hmax, max) != 0)
930 estate_clear_fuzzy_max(state);
931 } else if (!estate_has_fuzzy_max(sm->state)) {
932 estate_clear_fuzzy_max(state);
933 }
934
935 set_extra_mod(sm->name, sm->sym, iter_expr, state);
936 }
937
938 static bool get_global_rl(const char *name, struct symbol *sym, struct range_list **rl)
939 {
940 struct expression *expr;
941
942 if (!sym || !(sym->ctype.modifiers & MOD_TOPLEVEL) || !sym->ident)
943 return false;
944 if (strcmp(sym->ident->name, name) != 0)
945 return false;
946
947 expr = symbol_expression(sym);
948 return get_implied_rl(expr, rl);
949 }
950
951 static struct stree *unmatched_stree;
952 static struct smatch_state *unmatched_state(struct sm_state *sm)
953 {
954 struct smatch_state *state;
955 struct range_list *rl;
956
957 if (unmatched_stree) {
958 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
959 if (state)
960 return state;
961 }
962 if (parent_is_gone_var_sym(sm->name, sm->sym))
963 return alloc_estate_empty();
964 if (get_global_rl(sm->name, sm->sym, &rl))
965 return alloc_estate_rl(rl);
966 return alloc_estate_whole(estate_type(sm->state));
967 }
968
969 static void clear_the_pointed_at(struct expression *expr)
970 {
971 struct stree *stree;
972 char *name;
973 struct symbol *sym;
974 struct sm_state *tmp;
975
976 name = expr_to_var_sym(expr, &sym);
977 if (!name || !sym)
978 goto free;
979
980 stree = __get_cur_stree();
981 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
982 if (tmp->name[0] != '*')
983 continue;
984 if (tmp->sym != sym)
985 continue;
986 if (strcmp(tmp->name + 1, name) != 0)
987 continue;
988 set_extra_mod(tmp->name, tmp->sym, expr, alloc_estate_whole(estate_type(tmp->state)));
989 } END_FOR_EACH_SM(tmp);
990
991 free:
992 free_string(name);
993 }
994
995 static int is_const_param(struct expression *expr, int param)
996 {
997 struct symbol *type;
998
999 type = get_arg_type(expr, param);
1000 if (!type)
1001 return 0;
1002 if (type->ctype.modifiers & MOD_CONST)
1003 return 1;
1004 return 0;
1005 }
1006
1007 static void match_function_call(struct expression *expr)
1008 {
1009 struct expression *arg;
1010 struct expression *tmp;
1011 int param = -1;
1012
1013 /* if we have the db this is handled in smatch_function_hooks.c */
1014 if (!option_no_db)
1015 return;
1016 if (inlinable(expr->fn))
1017 return;
1018
1019 FOR_EACH_PTR(expr->args, arg) {
1020 param++;
1021 if (is_const_param(expr->fn, param))
1022 continue;
1023 tmp = strip_expr(arg);
1024 if (tmp->type == EXPR_PREOP && tmp->op == '&')
1025 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
1026 else
1027 clear_the_pointed_at(tmp);
1028 } END_FOR_EACH_PTR(arg);
1029 }
1030
1031 int values_fit_type(struct expression *left, struct expression *right)
1032 {
1033 struct range_list *rl;
1034 struct symbol *type;
1035
1036 type = get_type(left);
1037 if (!type)
1038 return 0;
1039 get_absolute_rl(right, &rl);
1040 if (type == rl_type(rl))
1041 return 1;
1042 if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
1043 return 0;
1044 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
1045 return 0;
1046 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
1047 return 0;
1048 return 1;
1049 }
1050
1051 static void save_chunk_info(struct expression *left, struct expression *right)
1052 {
1053 struct var_sym_list *vsl;
1054 struct var_sym *vs;
1055 struct expression *add_expr;
1056 struct symbol *type;
1057 sval_t sval;
1058 char *name;
1059 struct symbol *sym;
1060
1061 if (right->type != EXPR_BINOP || right->op != '-')
1062 return;
1063 if (!get_value(right->left, &sval))
1064 return;
1065 if (!expr_to_sym(right->right))
1066 return;
1067
1068 add_expr = binop_expression(left, '+', right->right);
1069 type = get_type(add_expr);
1070 if (!type)
1071 return;
1072 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
1073 if (!name || !vsl)
1074 goto free;
1075 FOR_EACH_PTR(vsl, vs) {
1076 store_link(link_id, vs->var, vs->sym, name, sym);
1077 } END_FOR_EACH_PTR(vs);
1078
1079 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
1080 free:
1081 free_string(name);
1082 }
1083
1084 static void do_array_assign(struct expression *left, int op, struct expression *right)
1085 {
1086 struct range_list *rl;
1087
1088 if (op == '=') {
1089 get_absolute_rl(right, &rl);
1090 rl = cast_rl(get_type(left), rl);
1091 } else {
1092 rl = alloc_whole_rl(get_type(left));
1093 }
1094
1095 set_extra_array_mod(left, alloc_estate_rl(rl));
1096 }
1097
1098 static void match_vanilla_assign(struct expression *left, struct expression *right)
1099 {
1100 struct range_list *orig_rl = NULL;
1101 struct range_list *rl = NULL;
1102 struct symbol *right_sym;
1103 struct symbol *left_type;
1104 struct symbol *right_type;
1105 char *right_name = NULL;
1106 struct symbol *sym;
1107 char *name;
1108 sval_t sval, max;
1109 struct smatch_state *state;
1110 int comparison;
1111
1112 if (is_struct(left))
1113 return;
1114
1115 save_chunk_info(left, right);
1116
1117 name = expr_to_var_sym(left, &sym);
1118 if (!name) {
1119 if (chunk_has_array(left))
1120 do_array_assign(left, '=', right);
1121 return;
1122 }
1123
1124 left_type = get_type(left);
1125 right_type = get_type(right);
1126
1127 right_name = expr_to_var_sym(right, &right_sym);
1128
1129 if (!__in_fake_assign &&
1130 !(right->type == EXPR_PREOP && right->op == '&') &&
1131 right_name && right_sym &&
1132 values_fit_type(left, strip_expr(right)) &&
1133 !has_symbol(right, sym)) {
1134 set_equiv(left, right);
1135 goto free;
1136 }
1137
1138 if (get_implied_value(right, &sval)) {
1139 state = alloc_estate_sval(sval_cast(left_type, sval));
1140 goto done;
1141 }
1142
1143 if (__in_fake_assign || is_fake_var(left)) {
1144 struct smatch_state *right_state;
1145 struct range_list *rl;
1146
1147 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
1148 if (right_state) {
1149 /* simple assignment */
1150 state = clone_estate(right_state);
1151 goto done;
1152 }
1153
1154 if (get_implied_rl(right, &rl)) {
1155 rl = cast_rl(left_type, rl);
1156 state = alloc_estate_rl(rl);
1157 goto done;
1158 }
1159
1160 rl = alloc_whole_rl(right_type);
1161 rl = cast_rl(left_type, rl);
1162 state = alloc_estate_rl(rl);
1163 goto done;
1164 }
1165
1166 comparison = get_comparison_no_extra(left, right);
1167 if (comparison) {
1168 comparison = flip_comparison(comparison);
1169 get_implied_rl(left, &orig_rl);
1170 }
1171
1172 if (get_implied_rl(right, &rl)) {
1173 rl = cast_rl(left_type, rl);
1174 if (orig_rl)
1175 filter_by_comparison(&rl, comparison, orig_rl);
1176 state = alloc_estate_rl(rl);
1177 if (get_hard_max(right, &max)) {
1178 estate_set_hard_max(state);
1179 estate_set_fuzzy_max(state, max);
1180 }
1181 } else {
1182 rl = alloc_whole_rl(right_type);
1183 rl = cast_rl(left_type, rl);
1184 if (orig_rl)
1185 filter_by_comparison(&rl, comparison, orig_rl);
1186 state = alloc_estate_rl(rl);
1187 }
1188
1189 done:
1190 set_extra_mod(name, sym, left, state);
1191 free:
1192 free_string(right_name);
1193 }
1194
1195 static void match_assign(struct expression *expr)
1196 {
1197 struct range_list *rl = NULL;
1198 struct expression *left;
1199 struct expression *right;
1200 struct expression *binop_expr;
1201 struct symbol *left_type;
1202 struct symbol *sym;
1203 char *name;
1204
1205 left = strip_expr(expr->left);
1206
1207 right = strip_parens(expr->right);
1208 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
1209 right = get_argument_from_call_expr(right->args, 0);
1210 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
1211 right = strip_parens(right->left);
1212
1213 if (expr->op == '=' && is_condition(expr->right))
1214 return; /* handled in smatch_condition.c */
1215 if (expr->op == '=' && right->type == EXPR_CALL &&
1216 !is_fake_call(right))
1217 return; /* handled in smatch_function_hooks.c */
1218 if (expr->op == '=') {
1219 match_vanilla_assign(left, right);
1220 return;
1221 }
1222
1223 name = expr_to_var_sym(left, &sym);
1224 if (!name)
1225 return;
1226
1227 left_type = get_type(left);
1228
1229 switch (expr->op) {
1230 case SPECIAL_ADD_ASSIGN:
1231 case SPECIAL_SUB_ASSIGN:
1232 case SPECIAL_AND_ASSIGN:
1233 case SPECIAL_MOD_ASSIGN:
1234 case SPECIAL_SHL_ASSIGN:
1235 case SPECIAL_SHR_ASSIGN:
1236 case SPECIAL_OR_ASSIGN:
1237 case SPECIAL_XOR_ASSIGN:
1238 case SPECIAL_MUL_ASSIGN:
1239 case SPECIAL_DIV_ASSIGN:
1240 binop_expr = binop_expression(expr->left,
1241 op_remove_assign(expr->op),
1242 expr->right);
1243 get_absolute_rl(binop_expr, &rl);
1244 rl = cast_rl(left_type, rl);
1245 if (inside_loop()) {
1246 if (expr->op == SPECIAL_ADD_ASSIGN)
1247 add_range(&rl, rl_max(rl), sval_type_max(rl_type(rl)));
1248
1249 if (expr->op == SPECIAL_SUB_ASSIGN &&
1250 !sval_is_negative(rl_min(rl))) {
1251 sval_t zero = { .type = rl_type(rl) };
1252
1253 add_range(&rl, rl_min(rl), zero);
1254 }
1255 }
1256 set_extra_mod(name, sym, left, alloc_estate_rl(rl));
1257 goto free;
1258 }
1259 set_extra_mod(name, sym, left, alloc_estate_whole(left_type));
1260 free:
1261 free_string(name);
1262 }
1263
1264 static struct smatch_state *increment_state(struct smatch_state *state)
1265 {
1266 sval_t min = estate_min(state);
1267 sval_t max = estate_max(state);
1268
1269 if (!estate_rl(state))
1270 return NULL;
1271
1272 if (inside_loop())
1273 max = sval_type_max(max.type);
1274
1275 if (!sval_is_min(min) && !sval_is_max(min))
1276 min.value++;
1277 if (!sval_is_min(max) && !sval_is_max(max))
1278 max.value++;
1279 return alloc_estate_range(min, max);
1280 }
1281
1282 static struct smatch_state *decrement_state(struct smatch_state *state)
1283 {
1284 sval_t min = estate_min(state);
1285 sval_t max = estate_max(state);
1286
1287 if (!estate_rl(state))
1288 return NULL;
1289
1290 if (inside_loop())
1291 min = sval_type_min(min.type);
1292
1293 if (!sval_is_min(min) && !sval_is_max(min))
1294 min.value--;
1295 if (!sval_is_min(max) && !sval_is_max(max))
1296 max.value--;
1297 return alloc_estate_range(min, max);
1298 }
1299
1300 static void clear_pointed_at_state(struct expression *expr)
1301 {
1302 struct symbol *type;
1303
1304 /*
1305 * ALERT: This is sort of a mess. If it's is a struct assigment like
1306 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1307 * the same thing for p++ where "p" is a struct. Most modifications
1308 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1309 * use smatch_modification.c because we have to get the ordering right
1310 * or something. So if you have p++ where p is a pointer to a standard
1311 * c type then we handle that here. What a mess.
1312 */
1313 expr = strip_expr(expr);
1314 type = get_type(expr);
1315 if (!type || type->type != SYM_PTR)
1316 return;
1317 type = get_real_base_type(type);
1318 if (!type || type->type != SYM_BASETYPE)
1319 return;
1320 set_extra_expr_nomod(deref_expression(expr), alloc_estate_whole(type));
1321 }
1322
1323 static void unop_expr(struct expression *expr)
1324 {
1325 struct smatch_state *state;
1326
1327 if (expr->smatch_flags & Handled)
1328 return;
1329
1330 switch (expr->op) {
1331 case SPECIAL_INCREMENT:
1332 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1333 state = increment_state(state);
1334 if (!state)
1335 state = alloc_estate_whole(get_type(expr));
1336 set_extra_expr_mod(expr->unop, state);
1337 clear_pointed_at_state(expr->unop);
1338 break;
1339 case SPECIAL_DECREMENT:
1340 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1341 state = decrement_state(state);
1342 if (!state)
1343 state = alloc_estate_whole(get_type(expr));
1344 set_extra_expr_mod(expr->unop, state);
1345 clear_pointed_at_state(expr->unop);
1346 break;
1347 default:
1348 return;
1349 }
1350 }
1351
1352 static void asm_expr(struct statement *stmt)
1353 {
1354 struct asm_operand *op;
1355 struct symbol *type;
1356
1357 FOR_EACH_PTR(stmt->asm_outputs, op) {
1358 type = get_type(strip_expr(op->expr));
1359 set_extra_expr_mod(op->expr, alloc_estate_whole(type));
1360 } END_FOR_EACH_PTR(op);
1361 }
1362
1363 static void check_dereference(struct expression *expr)
1364 {
1365 struct smatch_state *state;
1366
1367 if (__in_fake_assign)
1368 return;
1369 if (outside_of_function())
1370 return;
1371 state = get_extra_state(expr);
1372 if (state) {
1373 struct range_list *rl;
1374
1375 rl = rl_intersection(estate_rl(state), valid_ptr_rl);
1376 if (rl_equiv(rl, estate_rl(state)))
1377 return;
1378 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1379 } else {
1380 struct range_list *rl;
1381
1382 if (get_mtag_rl(expr, &rl))
1383 rl = rl_intersection(rl, valid_ptr_rl);
1384 else
1385 rl = clone_rl(valid_ptr_rl);
1386
1387 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1388 }
1389 }
1390
1391 static void match_dereferences(struct expression *expr)
1392 {
1393 if (expr->type != EXPR_PREOP)
1394 return;
1395 if (getting_address(expr))
1396 return;
1397 /* it's saying that foo[1] = bar dereferences foo[1] */
1398 if (is_array(expr))
1399 return;
1400 check_dereference(expr->unop);
1401 }
1402
1403 static void match_pointer_as_array(struct expression *expr)
1404 {
1405 if (!is_array(expr))
1406 return;
1407 check_dereference(get_array_base(expr));
1408 }
1409
1410 static void find_dereferences(struct expression *expr)
1411 {
1412 while (expr->type == EXPR_PREOP) {
1413 if (expr->op == '*')
1414 check_dereference(expr->unop);
1415 expr = strip_expr(expr->unop);
1416 }
1417 }
1418
1419 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
1420 {
1421 struct symbol *sym;
1422 char *name;
1423
1424 name = get_variable_from_key(arg, key, &sym);
1425 if (name && sym) {
1426 struct smatch_state *orig, *new;
1427 struct range_list *rl;
1428
1429 orig = get_state(SMATCH_EXTRA, name, sym);
1430 if (orig) {
1431 rl = rl_intersection(estate_rl(orig),
1432 alloc_rl(valid_ptr_min_sval,
1433 valid_ptr_max_sval));
1434 new = alloc_estate_rl(rl);
1435 } else {
1436 new = alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval);
1437 }
1438
1439 set_extra_nomod(name, sym, NULL, new);
1440 }
1441 free_string(name);
1442
1443 find_dereferences(arg);
1444 }
1445
1446 static sval_t add_one(sval_t sval)
1447 {
1448 sval.value++;
1449 return sval;
1450 }
1451
1452 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1453 {
1454 struct statement *stmt;
1455 struct expression *cond;
1456 struct smatch_state *true_state, *false_state;
1457 struct symbol *type;
1458 sval_t start;
1459 sval_t limit;
1460
1461 /*
1462 * If we're decrementing here then that's a canonical while count down
1463 * so it's handled already. We're only handling loops like:
1464 * i = 0;
1465 * do { ... } while (i++ < 3);
1466 */
1467
1468 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1469 return 0;
1470
1471 stmt = __cur_stmt->parent;
1472 if (!stmt)
1473 return 0;
1474 if (stmt->type == STMT_COMPOUND)
1475 stmt = stmt->parent;
1476 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1477 return 0;
1478
1479 cond = strip_expr(stmt->iterator_post_condition);
1480 if (cond->type != EXPR_COMPARE || cond->op != op)
1481 return 0;
1482 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1483 return 0;
1484
1485 if (!get_implied_value(left->unop, &start))
1486 return 0;
1487 if (!get_implied_value(right, &limit))
1488 return 0;
1489 type = get_type(left->unop);
1490 limit = sval_cast(type, limit);
1491 if (sval_cmp(start, limit) > 0)
1492 return 0;
1493
1494 switch (op) {
1495 case '<':
1496 case SPECIAL_UNSIGNED_LT:
1497 break;
1498 case SPECIAL_LTE:
1499 case SPECIAL_UNSIGNED_LTE:
1500 limit = add_one(limit);
1501 default:
1502 return 0;
1503
1504 }
1505
1506 true_state = alloc_estate_range(add_one(start), limit);
1507 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1508
1509 /* Currently we just discard the false state but when two passes is
1510 * implimented correctly then it will use it.
1511 */
1512
1513 set_extra_expr_true_false(left->unop, true_state, false_state);
1514
1515 return 1;
1516 }
1517
1518 bool is_impossible_variable(struct expression *expr)
1519 {
1520 struct smatch_state *state;
1521
1522 state = get_extra_state(expr);
1523 if (state && !estate_rl(state))
1524 return true;
1525 return false;
1526 }
1527
1528 static bool in_macro(struct expression *left, struct expression *right)
1529 {
1530 if (!left || !right)
1531 return 0;
1532 if (left->pos.line != right->pos.line || left->pos.pos != right->pos.pos)
1533 return 0;
1534 if (get_macro_name(left->pos))
1535 return 1;
1536 return 0;
1537 }
1538
1539 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1540 {
1541 struct range_list *left_orig;
1542 struct range_list *left_true;
1543 struct range_list *left_false;
1544 struct range_list *right_orig;
1545 struct range_list *right_true;
1546 struct range_list *right_false;
1547 struct smatch_state *left_true_state;
1548 struct smatch_state *left_false_state;
1549 struct smatch_state *right_true_state;
1550 struct smatch_state *right_false_state;
1551 sval_t dummy, hard_max;
1552 int left_postop = 0;
1553 int right_postop = 0;
1554
1555 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1556 if (left->type == EXPR_POSTOP) {
1557 left->smatch_flags |= Handled;
1558 left_postop = left->op;
1559 if (handle_postop_inc(left, op, right))
1560 return;
1561 }
1562 left = strip_parens(left->unop);
1563 }
1564 while (left->type == EXPR_ASSIGNMENT)
1565 left = strip_parens(left->left);
1566
1567 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1568 if (right->type == EXPR_POSTOP) {
1569 right->smatch_flags |= Handled;
1570 right_postop = right->op;
1571 }
1572 right = strip_parens(right->unop);
1573 }
1574
1575 if (is_impossible_variable(left) || is_impossible_variable(right))
1576 return;
1577
1578 get_real_absolute_rl(left, &left_orig);
1579 left_orig = cast_rl(type, left_orig);
1580
1581 get_real_absolute_rl(right, &right_orig);
1582 right_orig = cast_rl(type, right_orig);
1583
1584 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1585
1586 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1587 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1588 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1589 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1590
1591 if (!left_true || !left_false) {
1592 struct range_list *tmp_true, *tmp_false;
1593
1594 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1595 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1596 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1597 if (tmp_true && tmp_false)
1598 __save_imaginary_state(left, tmp_true, tmp_false);
1599 }
1600
1601 if (!right_true || !right_false) {
1602 struct range_list *tmp_true, *tmp_false;
1603
1604 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1605 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1606 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1607 if (tmp_true && tmp_false)
1608 __save_imaginary_state(right, tmp_true, tmp_false);
1609 }
1610
1611 left_true_state = alloc_estate_rl(left_true);
1612 left_false_state = alloc_estate_rl(left_false);
1613 right_true_state = alloc_estate_rl(right_true);
1614 right_false_state = alloc_estate_rl(right_false);
1615
1616 switch (op) {
1617 case '<':
1618 case SPECIAL_UNSIGNED_LT:
1619 case SPECIAL_UNSIGNED_LTE:
1620 case SPECIAL_LTE:
1621 if (get_hard_max(right, &dummy) && !in_macro(left, right))
1622 estate_set_hard_max(left_true_state);
1623 if (get_hard_max(left, &dummy) && !in_macro(left, right))
1624 estate_set_hard_max(right_false_state);
1625 break;
1626 case '>':
1627 case SPECIAL_UNSIGNED_GT:
1628 case SPECIAL_UNSIGNED_GTE:
1629 case SPECIAL_GTE:
1630 if (get_hard_max(left, &dummy) && !in_macro(left, right))
1631 estate_set_hard_max(right_true_state);
1632 if (get_hard_max(right, &dummy) && !in_macro(left, right))
1633 estate_set_hard_max(left_false_state);
1634 break;
1635 }
1636
1637 switch (op) {
1638 case '<':
1639 case SPECIAL_UNSIGNED_LT:
1640 case SPECIAL_UNSIGNED_LTE:
1641 case SPECIAL_LTE:
1642 if (get_hard_max(right, &hard_max)) {
1643 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1644 hard_max.value--;
1645 estate_set_fuzzy_max(left_true_state, hard_max);
1646 }
1647 if (get_implied_value(right, &hard_max)) {
1648 if (op == SPECIAL_UNSIGNED_LTE ||
1649 op == SPECIAL_LTE)
1650 hard_max.value++;
1651 estate_set_fuzzy_max(left_false_state, hard_max);
1652 }
1653 if (get_hard_max(left, &hard_max)) {
1654 if (op == SPECIAL_UNSIGNED_LTE ||
1655 op == SPECIAL_LTE)
1656 hard_max.value--;
1657 estate_set_fuzzy_max(right_false_state, hard_max);
1658 }
1659 if (get_implied_value(left, &hard_max)) {
1660 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1661 hard_max.value++;
1662 estate_set_fuzzy_max(right_true_state, hard_max);
1663 }
1664 break;
1665 case '>':
1666 case SPECIAL_UNSIGNED_GT:
1667 case SPECIAL_UNSIGNED_GTE:
1668 case SPECIAL_GTE:
1669 if (get_hard_max(left, &hard_max)) {
1670 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1671 hard_max.value--;
1672 estate_set_fuzzy_max(right_true_state, hard_max);
1673 }
1674 if (get_implied_value(left, &hard_max)) {
1675 if (op == SPECIAL_UNSIGNED_GTE ||
1676 op == SPECIAL_GTE)
1677 hard_max.value++;
1678 estate_set_fuzzy_max(right_false_state, hard_max);
1679 }
1680 if (get_hard_max(right, &hard_max)) {
1681 if (op == SPECIAL_UNSIGNED_LTE ||
1682 op == SPECIAL_LTE)
1683 hard_max.value--;
1684 estate_set_fuzzy_max(left_false_state, hard_max);
1685 }
1686 if (get_implied_value(right, &hard_max)) {
1687 if (op == '>' ||
1688 op == SPECIAL_UNSIGNED_GT)
1689 hard_max.value++;
1690 estate_set_fuzzy_max(left_true_state, hard_max);
1691 }
1692 break;
1693 case SPECIAL_EQUAL:
1694 if (get_hard_max(left, &hard_max))
1695 estate_set_fuzzy_max(right_true_state, hard_max);
1696 if (get_hard_max(right, &hard_max))
1697 estate_set_fuzzy_max(left_true_state, hard_max);
1698 break;
1699 }
1700
1701 if (get_hard_max(left, &hard_max)) {
1702 estate_set_hard_max(left_true_state);
1703 estate_set_hard_max(left_false_state);
1704 }
1705 if (get_hard_max(right, &hard_max)) {
1706 estate_set_hard_max(right_true_state);
1707 estate_set_hard_max(right_false_state);
1708 }
1709
1710 if (left_postop == SPECIAL_INCREMENT) {
1711 left_true_state = increment_state(left_true_state);
1712 left_false_state = increment_state(left_false_state);
1713 }
1714 if (left_postop == SPECIAL_DECREMENT) {
1715 left_true_state = decrement_state(left_true_state);
1716 left_false_state = decrement_state(left_false_state);
1717 }
1718 if (right_postop == SPECIAL_INCREMENT) {
1719 right_true_state = increment_state(right_true_state);
1720 right_false_state = increment_state(right_false_state);
1721 }
1722 if (right_postop == SPECIAL_DECREMENT) {
1723 right_true_state = decrement_state(right_true_state);
1724 right_false_state = decrement_state(right_false_state);
1725 }
1726
1727 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1728 left_true_state = NULL;
1729 left_false_state = NULL;
1730 }
1731
1732 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1733 right_true_state = NULL;
1734 right_false_state = NULL;
1735 }
1736
1737 /* Don't introduce new states for known true/false conditions */
1738 if (rl_equiv(left_orig, estate_rl(left_true_state)))
1739 left_true_state = NULL;
1740 if (rl_equiv(left_orig, estate_rl(left_false_state)))
1741 left_false_state = NULL;
1742 if (rl_equiv(right_orig, estate_rl(right_true_state)))
1743 right_true_state = NULL;
1744 if (rl_equiv(right_orig, estate_rl(right_false_state)))
1745 right_false_state = NULL;
1746
1747 set_extra_expr_true_false(left, left_true_state, left_false_state);
1748 set_extra_expr_true_false(right, right_true_state, right_false_state);
1749 }
1750
1751 static int is_simple_math(struct expression *expr)
1752 {
1753 if (!expr)
1754 return 0;
1755 if (expr->type != EXPR_BINOP)
1756 return 0;
1757 switch (expr->op) {
1758 case '+':
1759 case '-':
1760 case '*':
1761 return 1;
1762 }
1763 return 0;
1764 }
1765
1766 static int flip_op(int op)
1767 {
1768 /* We only care about simple math */
1769 switch (op) {
1770 case '+':
1771 return '-';
1772 case '-':
1773 return '+';
1774 case '*':
1775 return '/';
1776 }
1777 return 0;
1778 }
1779
1780 static void move_known_to_rl(struct expression **expr_p, struct range_list **rl_p)
1781 {
1782 struct expression *expr = *expr_p;
1783 struct range_list *rl = *rl_p;
1784 sval_t sval;
1785
1786 if (!is_simple_math(expr))
1787 return;
1788
1789 if (get_implied_value(expr->right, &sval)) {
1790 *expr_p = expr->left;
1791 *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
1792 move_known_to_rl(expr_p, rl_p);
1793 return;
1794 }
1795 if (expr->op == '-')
1796 return;
1797 if (get_implied_value(expr->left, &sval)) {
1798 *expr_p = expr->right;
1799 *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
1800 move_known_to_rl(expr_p, rl_p);
1801 return;
1802 }
1803 }
1804
1805 static void move_known_values(struct expression **left_p, struct expression **right_p)
1806 {
1807 struct expression *left = *left_p;
1808 struct expression *right = *right_p;
1809 sval_t sval, dummy;
1810
1811 if (get_implied_value(left, &sval)) {
1812 if (!is_simple_math(right))
1813 return;
1814 if (get_implied_value(right, &dummy))
1815 return;
1816 if (right->op == '*') {
1817 sval_t divisor;
1818
1819 if (!get_value(right->right, &divisor))
1820 return;
1821 if (divisor.value == 0)
1822 return;
1823 *left_p = binop_expression(left, invert_op(right->op), right->right);
1824 *right_p = right->left;
1825 return;
1826 }
1827 if (right->op == '+' && get_value(right->left, &sval)) {
1828 *left_p = binop_expression(left, invert_op(right->op), right->left);
1829 *right_p = right->right;
1830 return;
1831 }
1832 if (get_value(right->right, &sval)) {
1833 *left_p = binop_expression(left, invert_op(right->op), right->right);
1834 *right_p = right->left;
1835 return;
1836 }
1837 return;
1838 }
1839 if (get_implied_value(right, &sval)) {
1840 if (!is_simple_math(left))
1841 return;
1842 if (get_implied_value(left, &dummy))
1843 return;
1844 if (left->op == '*') {
1845 sval_t divisor;
1846
1847 if (!get_value(left->right, &divisor))
1848 return;
1849 if (divisor.value == 0)
1850 return;
1851 *right_p = binop_expression(right, invert_op(left->op), left->right);
1852 *left_p = left->left;
1853 return;
1854 }
1855 if (left->op == '+' && get_value(left->left, &sval)) {
1856 *right_p = binop_expression(right, invert_op(left->op), left->left);
1857 *left_p = left->right;
1858 return;
1859 }
1860
1861 if (get_value(left->right, &sval)) {
1862 *right_p = binop_expression(right, invert_op(left->op), left->right);
1863 *left_p = left->left;
1864 return;
1865 }
1866 return;
1867 }
1868 }
1869
1870 /*
1871 * The reason for do_simple_algebra() is to solve things like:
1872 * if (foo > 66 || foo + bar > 64) {
1873 * "foo" is not really a known variable so it won't be handled by
1874 * move_known_variables() but it's a super common idiom.
1875 *
1876 */
1877 static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
1878 {
1879 struct expression *left = *left_p;
1880 struct expression *right = *right_p;
1881 struct range_list *rl;
1882 sval_t tmp;
1883
1884 if (left->type != EXPR_BINOP || left->op != '+')
1885 return 0;
1886 if (can_integer_overflow(get_type(left), left))
1887 return 0;
1888 if (!get_implied_value(right, &tmp))
1889 return 0;
1890
1891 if (!get_implied_value(left->left, &tmp) &&
1892 get_implied_rl(left->left, &rl) &&
1893 !is_whole_rl(rl)) {
1894 *right_p = binop_expression(right, '-', left->left);
1895 *left_p = left->right;
1896 return 1;
1897 }
1898 if (!get_implied_value(left->right, &tmp) &&
1899 get_implied_rl(left->right, &rl) &&
1900 !is_whole_rl(rl)) {
1901 *right_p = binop_expression(right, '-', left->right);
1902 *left_p = left->left;
1903 return 1;
1904 }
1905
1906 return 0;
1907 }
1908
1909 static int match_func_comparison(struct expression *expr)
1910 {
1911 struct expression *left = strip_expr(expr->left);
1912 struct expression *right = strip_expr(expr->right);
1913
1914 if (left->type == EXPR_CALL || right->type == EXPR_CALL) {
1915 function_comparison(left, expr->op, right);
1916 return 1;
1917 }
1918
1919 return 0;
1920 }
1921
1922 /* Handle conditions like "if (foo + bar < foo) {" */
1923 static int handle_integer_overflow_test(struct expression *expr)
1924 {
1925 struct expression *left, *right;
1926 struct symbol *type;
1927 sval_t left_min, right_min, min, max;
1928
1929 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
1930 return 0;
1931
1932 left = strip_parens(expr->left);
1933 right = strip_parens(expr->right);
1934
1935 if (left->op != '+')
1936 return 0;
1937
1938 type = get_type(expr);
1939 if (!type)
1940 return 0;
1941 if (type_positive_bits(type) == 32) {
1942 max.type = &uint_ctype;
1943 max.uvalue = (unsigned int)-1;
1944 } else if (type_positive_bits(type) == 64) {
1945 max.type = &ulong_ctype;
1946 max.value = (unsigned long long)-1;
1947 } else {
1948 return 0;
1949 }
1950
1951 if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
1952 return 0;
1953
1954 get_absolute_min(left->left, &left_min);
1955 get_absolute_min(left->right, &right_min);
1956 min = sval_binop(left_min, '+', right_min);
1957
1958 type = get_type(left);
1959 min = sval_cast(type, min);
1960 max = sval_cast(type, max);
1961
1962 set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
1963 return 1;
1964 }
1965
1966 static void match_comparison(struct expression *expr)
1967 {
1968 struct expression *left_orig = strip_parens(expr->left);
1969 struct expression *right_orig = strip_parens(expr->right);
1970 struct expression *left, *right, *tmp;
1971 struct expression *prev;
1972 struct symbol *type;
1973 int redo, count;
1974
1975 if (match_func_comparison(expr))
1976 return;
1977
1978 type = get_type(expr);
1979 if (!type)
1980 type = &llong_ctype;
1981
1982 if (handle_integer_overflow_test(expr))
1983 return;
1984
1985 left = left_orig;
1986 right = right_orig;
1987 move_known_values(&left, &right);
1988 handle_comparison(type, left, expr->op, right);
1989
1990 left = left_orig;
1991 right = right_orig;
1992 if (do_simple_algebra(&left, &right))
1993 handle_comparison(type, left, expr->op, right);
1994
1995 prev = get_assigned_expr(left_orig);
1996 if (is_simple_math(prev) && !has_variable(prev, left_orig)) {
1997 left = prev;
1998 right = right_orig;
1999 move_known_values(&left, &right);
2000 handle_comparison(type, left, expr->op, right);
2001 }
2002
2003 prev = get_assigned_expr(right_orig);
2004 if (is_simple_math(prev) && !has_variable(prev, right_orig)) {
2005 left = left_orig;
2006 right = prev;
2007 move_known_values(&left, &right);
2008 handle_comparison(type, left, expr->op, right);
2009 }
2010
2011 redo = 0;
2012 left = left_orig;
2013 right = right_orig;
2014 if (get_last_expr_from_expression_stmt(left_orig)) {
2015 left = get_last_expr_from_expression_stmt(left_orig);
2016 redo = 1;
2017 }
2018 if (get_last_expr_from_expression_stmt(right_orig)) {
2019 right = get_last_expr_from_expression_stmt(right_orig);
2020 redo = 1;
2021 }
2022
2023 if (!redo)
2024 return;
2025
2026 count = 0;
2027 while ((tmp = get_assigned_expr(left))) {
2028 if (count++ > 3)
2029 break;
2030 left = strip_expr(tmp);
2031 }
2032 count = 0;
2033 while ((tmp = get_assigned_expr(right))) {
2034 if (count++ > 3)
2035 break;
2036 right = strip_expr(tmp);
2037 }
2038
2039 handle_comparison(type, left, expr->op, right);
2040 }
2041
2042 static sval_t get_high_mask(sval_t known)
2043 {
2044 sval_t ret;
2045 int i;
2046
2047 ret = known;
2048 ret.value = 0;
2049
2050 for (i = type_bits(known.type) - 1; i >= 0; i--) {
2051 if (known.uvalue & (1ULL << i))
2052 ret.uvalue |= (1ULL << i);
2053 else
2054 return ret;
2055
2056 }
2057 return ret;
2058 }
2059
2060 static bool handle_bit_test(struct expression *expr)
2061 {
2062 struct range_list *orig_rl, *rlt, *rlf, *true_rl, *false_rl;
2063 struct expression *shift, *mask, *var;
2064 struct bit_info *bit_info;
2065 sval_t sval;
2066 sval_t high = { .type = &int_ctype };
2067 sval_t low = { .type = &int_ctype };
2068
2069 shift = strip_expr(expr->right);
2070 mask = strip_expr(expr->left);
2071 if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT) {
2072 shift = strip_expr(expr->left);
2073 mask = strip_expr(expr->right);
2074 if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT)
2075 return false;
2076 }
2077 if (!get_implied_value(shift->left, &sval) || sval.value != 1)
2078 return false;
2079 var = strip_expr(shift->right);
2080
2081 bit_info = get_bit_info(mask);
2082 if (!bit_info)
2083 return false;
2084 if (!bit_info->possible){
2085 set_true_false_states_expr(my_id, var, alloc_estate_empty(), NULL);
2086 return false;
2087 }
2088
2089 get_absolute_rl(var, &orig_rl);
2090 if (sval_is_negative(rl_min(orig_rl)) ||
2091 rl_max(orig_rl).uvalue > type_bits(get_type(shift->left)))
2092 return false;
2093
2094 low.value = ffsll(bit_info->possible) - 1;
2095 high.value = sm_fls64(bit_info->possible) - 1;
2096 rlt = alloc_rl(low, high);
2097 rlt = cast_rl(get_type(var), rlt);
2098 true_rl = rl_intersection(orig_rl, rlt);
2099
2100 low.value = ffsll(bit_info->set) - 1;
2101 high.value = sm_fls64(bit_info->set) - 1;
2102 rlf = alloc_rl(low, high);
2103 rlf = cast_rl(get_type(var), rlf);
2104 false_rl = rl_filter(orig_rl, rlf);
2105
2106 set_extra_expr_true_false(shift->right, alloc_estate_rl(true_rl), alloc_estate_rl(false_rl));
2107
2108 return true;
2109 }
2110
2111 static void handle_AND_op(struct expression *var, sval_t known)
2112 {
2113 struct range_list *orig_rl;
2114 struct range_list *true_rl = NULL;
2115 struct range_list *false_rl = NULL;
2116 int bit;
2117 sval_t low_mask = known;
2118 sval_t high_mask;
2119 sval_t max;
2120
2121 get_absolute_rl(var, &orig_rl);
2122
2123 if (known.value > 0) {
2124 bit = ffsll(known.value) - 1;
2125 low_mask.uvalue = (1ULL << bit) - 1;
2126 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
2127 }
2128 high_mask = get_high_mask(known);
2129 if (high_mask.value) {
2130 bit = ffsll(high_mask.value) - 1;
2131 low_mask.uvalue = (1ULL << bit) - 1;
2132
2133 false_rl = orig_rl;
2134 if (sval_is_negative(rl_min(orig_rl)))
2135 false_rl = remove_range(false_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
2136 false_rl = remove_range(false_rl, low_mask, sval_type_max(known.type));
2137 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
2138 false_rl = remove_range(false_rl,
2139 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
2140 sval_type_val(rl_type(false_rl), -1));
2141 }
2142 } else if (known.value == 1 &&
2143 get_hard_max(var, &max) &&
2144 sval_cmp(max, rl_max(orig_rl)) == 0 &&
2145 max.value & 1) {
2146 false_rl = remove_range(orig_rl, max, max);
2147 }
2148 set_extra_expr_true_false(var,
2149 true_rl ? alloc_estate_rl(true_rl) : NULL,
2150 false_rl ? alloc_estate_rl(false_rl) : NULL);
2151 }
2152
2153 static void handle_AND_condition(struct expression *expr)
2154 {
2155 sval_t known;
2156
2157 if (handle_bit_test(expr))
2158 return;
2159
2160 if (get_implied_value(expr->left, &known))
2161 handle_AND_op(expr->right, known);
2162 else if (get_implied_value(expr->right, &known))
2163 handle_AND_op(expr->left, known);
2164 }
2165
2166 static void handle_MOD_condition(struct expression *expr)
2167 {
2168 struct range_list *orig_rl;
2169 struct range_list *true_rl;
2170 struct range_list *false_rl = NULL;
2171 sval_t right;
2172 sval_t zero = {
2173 .value = 0,
2174 };
2175
2176 if (!get_implied_value(expr->right, &right) || right.value == 0)
2177 return;
2178 get_absolute_rl(expr->left, &orig_rl);
2179
2180 zero.type = rl_type(orig_rl);
2181
2182 /* We're basically dorking around the min and max here */
2183 true_rl = remove_range(orig_rl, zero, zero);
2184 if (!sval_is_max(rl_max(true_rl)) &&
2185 !(rl_max(true_rl).value % right.value))
2186 true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));
2187
2188 if (rl_equiv(true_rl, orig_rl))
2189 true_rl = NULL;
2190
2191 if (sval_is_positive(rl_min(orig_rl)) &&
2192 (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
2193 sval_t add;
2194 int i;
2195
2196 add = rl_min(orig_rl);
2197 add.value += right.value - (add.value % right.value);
2198 add.value -= right.value;
2199
2200 for (i = 0; i < 5; i++) {
2201 add.value += right.value;
2202 if (add.value > rl_max(orig_rl).value)
2203 break;
2204 add_range(&false_rl, add, add);
2205 }
2206 } else {
2207 if (rl_min(orig_rl).uvalue != 0 &&
2208 rl_min(orig_rl).uvalue < right.uvalue) {
2209 sval_t chop = right;
2210 chop.value--;
2211 false_rl = remove_range(orig_rl, zero, chop);
2212 }
2213
2214 if (!sval_is_max(rl_max(orig_rl)) &&
2215 (rl_max(orig_rl).value % right.value)) {
2216 sval_t chop = rl_max(orig_rl);
2217 chop.value -= chop.value % right.value;
2218 chop.value++;
2219 if (!false_rl)
2220 false_rl = clone_rl(orig_rl);
2221 false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
2222 }
2223 }
2224
2225 set_extra_expr_true_false(expr->left,
2226 true_rl ? alloc_estate_rl(true_rl) : NULL,
2227 false_rl ? alloc_estate_rl(false_rl) : NULL);
2228 }
2229
2230 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
2231 void __extra_match_condition(struct expression *expr)
2232 {
2233 expr = strip_expr(expr);
2234 switch (expr->type) {
2235 case EXPR_CALL:
2236 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
2237 return;
2238 case EXPR_PREOP:
2239 case EXPR_SYMBOL:
2240 case EXPR_DEREF:
2241 handle_comparison(get_type(expr), expr, SPECIAL_NOTEQUAL, zero_expr());
2242 return;
2243 case EXPR_COMPARE:
2244 match_comparison(expr);
2245 return;
2246 case EXPR_ASSIGNMENT:
2247 __extra_match_condition(expr->left);
2248 return;
2249 case EXPR_BINOP:
2250 if (expr->op == '&')
2251 handle_AND_condition(expr);
2252 if (expr->op == '%')
2253 handle_MOD_condition(expr);
2254 return;
2255 }
2256 }
2257
2258 static void assume_indexes_are_valid(struct expression *expr)
2259 {
2260 struct expression *array_expr;
2261 int array_size;
2262 struct expression *offset;
2263 struct symbol *offset_type;
2264 struct range_list *rl_before;
2265 struct range_list *rl_after;
2266 struct range_list *filter = NULL;
2267 sval_t size;
2268
2269 expr = strip_expr(expr);
2270 if (!is_array(expr))
2271 return;
2272
2273 offset = get_array_offset(expr);
2274 offset_type = get_type(offset);
2275 if (offset_type && type_signed(offset_type)) {
2276 filter = alloc_rl(sval_type_min(offset_type),
2277 sval_type_val(offset_type, -1));
2278 }
2279
2280 array_expr = get_array_base(expr);
2281 array_size = get_real_array_size(array_expr);
2282 if (array_size > 1) {
2283 size = sval_type_val(offset_type, array_size);
2284 add_range(&filter, size, sval_type_max(offset_type));
2285 }
2286
2287 if (!filter)
2288 return;
2289 get_absolute_rl(offset, &rl_before);
2290 rl_after = rl_filter(rl_before, filter);
2291 if (rl_equiv(rl_before, rl_after))
2292 return;
2293 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
2294 }
2295
2296 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
2297 int implied_not_equal(struct expression *expr, long long val)
2298 {
2299 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
2300 }
2301
2302 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
2303 {
2304 struct smatch_state *estate;
2305
2306 estate = get_state(SMATCH_EXTRA, name, sym);
2307 if (!estate)
2308 return 0;
2309 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
2310 return 1;
2311 return 0;
2312 }
2313
2314 bool is_noderef_ptr(struct expression *expr)
2315 {
2316 struct range_list *rl;
2317
2318 if (!get_implied_rl(expr, &rl))
2319 return false;
2320 return is_noderef_ptr_rl(rl);
2321 }
2322
2323 static int parent_is_err_or_null_var_sym_helper(const char *name, struct symbol *sym, bool check_err_ptr)
2324 {
2325 struct smatch_state *state;
2326 char buf[256];
2327 char *start;
2328 int len;
2329
2330 strncpy(buf, name, sizeof(buf) - 1);
2331 buf[sizeof(buf) - 1] = '\0';
2332
2333 start = &buf[0];
2334 while (*start == '*') {
2335 start++;
2336 state = __get_state(SMATCH_EXTRA, start, sym);
2337 if (!state)
2338 continue;
2339 if (!estate_rl(state))
2340 return 1;
2341 if (is_noderef_ptr_rl(estate_rl(state)))
2342 return 1;
2343 }
2344
2345 start = &buf[0];
2346 while (*start == '&')
2347 start++;
2348
2349 len = strlen(start);
2350 while (true) {
2351 while (len > 0) {
2352 len--;
2353 if (start[len] == '-' ||
2354 start[len] == '.') {
2355 start[len] = '\0';
2356 break;
2357 }
2358 }
2359 if (len == 0)
2360 return 0;
2361 state = __get_state(SMATCH_EXTRA, start, sym);
2362 if (!state)
2363 continue;
2364 if (is_noderef_ptr_rl(estate_rl(state)))
2365 return 1;
2366 }
2367 }
2368
2369 int parent_is_null_var_sym(const char *name, struct symbol *sym)
2370 {
2371 return parent_is_err_or_null_var_sym_helper(name, sym, false);
2372 }
2373
2374 int parent_is_err_or_null_var_sym(const char *name, struct symbol *sym)
2375 {
2376 return parent_is_err_or_null_var_sym_helper(name, sym, (option_project == PROJ_KERNEL));
2377 }
2378
2379 int parent_is_null(struct expression *expr)
2380 {
2381 struct symbol *sym;
2382 char *var;
2383 int ret = 0;
2384
2385 expr = strip_expr(expr);
2386 var = expr_to_var_sym(expr, &sym);
2387 if (!var || !sym)
2388 goto free;
2389 ret = parent_is_null_var_sym(var, sym);
2390 free:
2391 free_string(var);
2392 return ret;
2393 }
2394
2395 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
2396 {
2397 *(int *)found = 1;
2398 return 0;
2399 }
2400
2401 static int is_kzalloc_info(struct sm_state *sm)
2402 {
2403 sval_t sval;
2404
2405 /*
2406 * kzalloc() information is treated as special because so there is just
2407 * a lot of stuff initialized to zero and it makes building the database
2408 * take hours and hours.
2409 *
2410 * In theory, we should just remove this line and not pass any unused
2411 * information, but I'm not sure enough that this code works so I want
2412 * to hold off on that for now.
2413 */
2414 if (!estate_get_single_value(sm->state, &sval))
2415 return 0;
2416 if (sval.value != 0)
2417 return 0;
2418 return 1;
2419 }
2420
2421 static int is_really_long(struct sm_state *sm)
2422 {
2423 const char *p;
2424 int cnt = 0;
2425
2426 p = sm->name;
2427 while ((p = strstr(p, "->"))) {
2428 p += 2;
2429 cnt++;
2430 }
2431
2432 if (cnt < 3 ||
2433 strlen(sm->name) < 40)
2434 return 0;
2435 return 1;
2436 }
2437
2438 static int filter_unused_param_value_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2439 {
2440 int found = 0;
2441
2442 /* for function pointers assume everything is used */
2443 if (call->fn->type != EXPR_SYMBOL)
2444 return 0;
2445
2446 if (strcmp(printed_name, "$") == 0 ||
2447 strcmp(printed_name, "*$") == 0)
2448 return 0;
2449
2450 /*
2451 * This is to handle __builtin_mul_overflow(). In an ideal world we
2452 * would only need this for invalid code.
2453 *
2454 */
2455 if (!call->fn->symbol)
2456 return 0;
2457
2458 if (!is_kzalloc_info(sm) && !is_really_long(sm))
2459 return 0;
2460
2461 run_sql(&param_used_callback, &found,
2462 "select * from return_implies where %s and type = %d and parameter = %d and key = '%s';",
2463 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
2464 if (found)
2465 return 0;
2466
2467 /* If the database is not built yet, then assume everything is used */
2468 run_sql(&param_used_callback, &found,
2469 "select * from return_implies where %s and type = %d;",
2470 get_static_filter(call->fn->symbol), PARAM_USED);
2471 if (!found)
2472 return 0;
2473
2474 return 1;
2475 }
2476
2477 struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
2478 {
2479 struct smatch_state *state;
2480
2481 /*
2482 * Here is the difference between implied value and real absolute, say
2483 * you have:
2484 *
2485 * int a = (u8)x;
2486 *
2487 * Then you know that a is 0-255. That's real absolute. But you don't
2488 * know for sure that it actually goes up to 255. So it's not implied.
2489 * Implied indicates a degree of certainty.
2490 *
2491 * But then say you cap "a" at 8. That means you know it goes up to
2492 * 8. So now the implied value is s32min-8. But you can combine it
2493 * with the real absolute to say that actually it's 0-8.
2494 *
2495 * We are combining it here. But now that I think about it, this is
2496 * probably not the ideal place to combine it because it should proably
2497 * be done earlier. Oh well, this is an improvement on what was there
2498 * before so I'm going to commit this code.
2499 *
2500 */
2501
2502 state = get_real_absolute_state_var_sym(name, sym);
2503 if (!state || !estate_rl(state))
2504 return start;
2505
2506 return rl_intersection(estate_rl(state), start);
2507 }
2508
2509 struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
2510 {
2511 struct smatch_state *state;
2512 struct range_list *abs_rl;
2513
2514 state = get_real_absolute_state(expr);
2515 if (!state || !estate_rl(state))
2516 return start;
2517
2518 abs_rl = cast_rl(rl_type(start), estate_rl(state));
2519 return rl_intersection(abs_rl, start);
2520 }
2521
2522 static void caller_info_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2523 {
2524 struct range_list *rl;
2525 sval_t dummy;
2526
2527 if (estate_is_whole(sm->state) || !estate_rl(sm->state))
2528 return;
2529 if (filter_unused_param_value_info(call, param, printed_name, sm))
2530 return;
2531 rl = estate_rl(sm->state);
2532 rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
2533 if (!rl)
2534 return;
2535 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
2536 if (!estate_get_single_value(sm->state, &dummy)) {
2537 if (estate_has_hard_max(sm->state))
2538 sql_insert_caller_info(call, HARD_MAX, param, printed_name,
2539 sval_to_str(estate_max(sm->state)));
2540 if (estate_has_fuzzy_max(sm->state))
2541 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
2542 sval_to_str(estate_get_fuzzy_max(sm->state)));
2543 }
2544 }
2545
2546 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
2547 {
2548 struct symbol *returned_sym;
2549 char *returned_name;
2550 struct sm_state *sm;
2551 char *compare_str;
2552 char name_buf[256];
2553 char val_buf[256];
2554 int len;
2555
2556 // FIXME handle *$
2557
2558 if (!is_pointer(expr))
2559 return;
2560 if (return_ranges && strstr(return_ranges, "[==$"))
2561 return;
2562
2563 returned_name = expr_to_var_sym(expr, &returned_sym);
2564 if (!returned_name || !returned_sym)
2565 goto free;
2566 len = strlen(returned_name);
2567
2568 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
2569 if (!estate_rl(sm->state))
2570 continue;
2571 if (returned_sym != sm->sym)
2572 continue;
2573 if (strncmp(returned_name, sm->name, len) != 0)
2574 continue;
2575 if (sm->name[len] != '-')
2576 continue;
2577
2578 snprintf(name_buf, sizeof(name_buf), "$%s", sm->name + len);
2579
2580 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
2581 if (!compare_str && estate_is_whole(sm->state))
2582 continue;
2583 snprintf(val_buf, sizeof(val_buf), "%s%s", sm->state->name, compare_str ?: "");
2584
2585 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
2586 -1, name_buf, val_buf);
2587 } END_FOR_EACH_SM(sm);
2588
2589 free:
2590 free_string(returned_name);
2591 }
2592
2593 static void db_limited_before(void)
2594 {
2595 unmatched_stree = clone_stree(__get_cur_stree());
2596 }
2597
2598 static void db_limited_after(void)
2599 {
2600 free_stree(&unmatched_stree);
2601 }
2602
2603 static int basically_the_same(struct range_list *orig, struct range_list *new)
2604 {
2605 if (type_is_ptr(rl_type(orig)) &&
2606 is_whole_ptr_rl(orig) &&
2607 is_whole_ptr_rl(new))
2608 return true;
2609
2610 return rl_equiv(orig, new);
2611 }
2612
2613 static void db_param_limit_binops(struct expression *arg, char *key, struct range_list *rl)
2614 {
2615 struct range_list *left_rl;
2616 sval_t zero = { .type = rl_type(rl), };
2617 sval_t sval;
2618
2619 if (strcmp(key, "$") != 0)
2620 return;
2621 if (arg->op != '*')
2622 return;
2623 if (!get_implied_value(arg->right, &sval))
2624 return;
2625 if (can_integer_overflow(get_type(arg), arg))
2626 return;
2627
2628 left_rl = rl_binop(rl, '/', alloc_rl(sval, sval));
2629 if (!rl_has_sval(rl, zero))
2630 left_rl = remove_range(left_rl, zero, zero);
2631
2632 set_extra_expr_nomod(arg->left, alloc_estate_rl(left_rl));
2633 }
2634
2635 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
2636 {
2637 struct smatch_state *state;
2638 struct expression *arg;
2639 char *name;
2640 struct symbol *sym;
2641 struct var_sym_list *vsl = NULL;
2642 struct sm_state *sm;
2643 struct symbol *compare_type, *var_type;
2644 struct range_list *rl;
2645 struct range_list *limit;
2646 struct range_list *new;
2647 char *other_name;
2648 struct symbol *other_sym;
2649
2650 while (expr->type == EXPR_ASSIGNMENT)
2651 expr = strip_expr(expr->right);
2652 if (expr->type != EXPR_CALL)
2653 return;
2654
2655 arg = get_argument_from_call_expr(expr->args, param);
2656 if (!arg)
2657 return;
2658
2659 if (strcmp(key, "$") == 0)
2660 compare_type = get_arg_type(expr->fn, param);
2661 else
2662 compare_type = get_member_type_from_key(arg, key);
2663
2664 call_results_to_rl(expr, compare_type, value, &limit);
2665 if (strcmp(key, "$") == 0)
2666 move_known_to_rl(&arg, &limit);
2667 name = get_chunk_from_key(arg, key, &sym, &vsl);
2668 if (!name)
2669 return;
2670 if (op != PARAM_LIMIT && !sym)
2671 goto free;
2672
2673 sm = get_sm_state(SMATCH_EXTRA, name, sym);
2674 if (sm)
2675 rl = estate_rl(sm->state);
2676 else
2677 rl = alloc_whole_rl(compare_type);
2678
2679 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
2680 goto free;
2681
2682 new = rl_intersection(rl, limit);
2683
2684 var_type = get_member_type_from_key(arg, key);
2685 new = cast_rl(var_type, new);
2686
2687 /* We want to preserve the implications here */
2688 if (sm && basically_the_same(rl, new))
2689 goto free;
2690 other_name = get_other_name_sym(name, sym, &other_sym);
2691
2692 state = alloc_estate_rl(new);
2693 if (sm && estate_has_hard_max(sm->state))
2694 estate_set_hard_max(state);
2695
2696 if (op == PARAM_LIMIT) {
2697 set_extra_nomod_vsl(name, sym, vsl, NULL, state);
2698 } else
2699 set_extra_mod(name, sym, NULL, state);
2700
2701 if (other_name && other_sym) {
2702 state = clone_estate(state);
2703 if (op == PARAM_LIMIT)
2704 set_extra_nomod_vsl(other_name, other_sym, vsl, NULL, state);
2705 else
2706 set_extra_mod(other_name, other_sym, NULL, state);
2707 }
2708
2709 if (op == PARAM_LIMIT && arg->type == EXPR_BINOP)
2710 db_param_limit_binops(arg, key, new);
2711 free:
2712 free_string(name);
2713 }
2714
2715 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
2716 {
2717 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
2718 }
2719
2720 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
2721 {
2722 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
2723 }
2724
2725 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
2726 {
2727 struct expression *arg, *gen_expr;
2728 char *name;
2729 char *other_name = NULL;
2730 struct symbol *sym, *other_sym;
2731 struct symbol *param_type, *arg_type;
2732 struct smatch_state *state;
2733 struct range_list *new = NULL;
2734 struct range_list *added = NULL;
2735
2736 while (expr->type == EXPR_ASSIGNMENT)
2737 expr = strip_expr(expr->right);
2738 if (expr->type != EXPR_CALL)
2739 return;
2740
2741 arg = get_argument_from_call_expr(expr->args, param);
2742 if (!arg)
2743 return;
2744
2745 arg_type = get_arg_type_from_key(expr->fn, param, arg, key);
2746 param_type = get_member_type_from_key(arg, key);
2747 if (param_type && param_type->type == SYM_STRUCT)
2748 return;
2749 name = get_variable_from_key(arg, key, &sym);
2750 if (!name || !sym)
2751 goto free;
2752 gen_expr = gen_expression_from_key(arg, key);
2753
2754 state = get_state(SMATCH_EXTRA, name, sym);
2755 if (state)
2756 new = estate_rl(state);
2757
2758 call_results_to_rl(expr, arg_type, value, &added);
2759 added = cast_rl(param_type, added);
2760 if (op == PARAM_SET)
2761 new = added;
2762 else
2763 new = rl_union(new, added);
2764
2765 other_name = get_other_name_sym_nostack(name, sym, &other_sym);
2766 set_extra_mod(name, sym, gen_expr, alloc_estate_rl(new));
2767 if (other_name && other_sym)
2768 set_extra_mod(other_name, other_sym, gen_expr, alloc_estate_rl(new));
2769 free:
2770 free_string(other_name);
2771 free_string(name);
2772 }
2773
2774 static void db_param_add(struct expression *expr, int param, char *key, char *value)
2775 {
2776 in_param_set = true;
2777 db_param_add_set(expr, param, key, value, PARAM_ADD);
2778 in_param_set = false;
2779 }
2780
2781 static void db_param_set(struct expression *expr, int param, char *key, char *value)
2782 {
2783 in_param_set = true;
2784 db_param_add_set(expr, param, key, value, PARAM_SET);
2785 in_param_set = false;
2786 }
2787
2788 static void match_lost_param(struct expression *call, int param)
2789 {
2790 struct expression *arg;
2791
2792 if (is_const_param(call->fn, param))
2793 return;
2794
2795 arg = get_argument_from_call_expr(call->args, param);
2796 if (!arg)
2797 return;
2798
2799 arg = strip_expr(arg);
2800 if (arg->type == EXPR_PREOP && arg->op == '&')
2801 set_extra_expr_mod(arg->unop, alloc_estate_whole(get_type(arg->unop)));
2802 else
2803 ; /* if pointer then set struct members, maybe?*/
2804 }
2805
2806 static void db_param_value(struct expression *expr, int param, char *key, char *value)
2807 {
2808 struct expression *call;
2809 char *name;
2810 struct symbol *sym;
2811 struct symbol *type;
2812 struct range_list *rl = NULL;
2813
2814 if (param != -1)
2815 return;
2816
2817 call = expr;
2818 while (call->type == EXPR_ASSIGNMENT)
2819 call = strip_expr(call->right);
2820 if (call->type != EXPR_CALL)
2821 return;
2822
2823 type = get_member_type_from_key(expr->left, key);
2824 name = get_variable_from_key(expr->left, key, &sym);
2825 if (!name || !sym)
2826 goto free;
2827
2828 call_results_to_rl(call, type, value, &rl);
2829
2830 set_extra_mod(name, sym, NULL, alloc_estate_rl(rl));
2831 free:
2832 free_string(name);
2833 }
2834
2835 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2836 {
2837 struct expression *expr;
2838 struct range_list *rl = NULL;
2839 struct smatch_state *state;
2840 struct symbol *type;
2841 char *key_orig = key;
2842 char *fullname;
2843 sval_t dummy;
2844
2845 expr = symbol_expression(sym);
2846 fullname = get_variable_from_key(expr, key, NULL);
2847 if (!fullname)
2848 return;
2849
2850 type = get_member_type_from_key(expr, key_orig);
2851 str_to_rl(type, value, &rl);
2852 state = alloc_estate_rl(rl);
2853 if (estate_get_single_value(state, &dummy))
2854 estate_set_hard_max(state);
2855 set_state(SMATCH_EXTRA, fullname, sym, state);
2856 }
2857
2858 static void set_param_fuzzy_max(const char *name, struct symbol *sym, char *key, char *value)
2859 {
2860 struct expression *expr;
2861 struct range_list *rl = NULL;
2862 struct smatch_state *state;
2863 struct symbol *type;
2864 char *fullname;
2865 sval_t max;
2866
2867 expr = symbol_expression(sym);
2868 fullname = get_variable_from_key(expr, key, NULL);
2869 if (!fullname)
2870 return;
2871
2872 state = get_state(SMATCH_EXTRA, fullname, sym);
2873 if (!state)
2874 return;
2875 type = estate_type(state);
2876 str_to_rl(type, value, &rl);
2877 if (!rl_to_sval(rl, &max))
2878 return;
2879 estate_set_fuzzy_max(state, max);
2880 }
2881
2882 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2883 {
2884 struct smatch_state *state;
2885 struct expression *expr;
2886 char *fullname;
2887
2888 expr = symbol_expression(sym);
2889 fullname = get_variable_from_key(expr, key, NULL);
2890 if (!fullname)
2891 return;
2892
2893 state = get_state(SMATCH_EXTRA, fullname, sym);
2894 if (!state)
2895 return;
2896 estate_set_hard_max(state);
2897 }
2898
2899 static struct sm_state *get_sm_from_call(struct expression *expr)
2900 {
2901 char buf[32];
2902
2903 if (is_fake_call(expr))
2904 return NULL;
2905
2906 snprintf(buf, sizeof(buf), "return %p", expr);
2907 return get_sm_state(SMATCH_EXTRA, buf, NULL);
2908 }
2909
2910 struct sm_state *get_extra_sm_state(struct expression *expr)
2911 {
2912 char *name;
2913 struct symbol *sym;
2914 struct sm_state *ret = NULL;
2915
2916 expr = strip_expr(expr);
2917 if (!expr)
2918 return NULL;
2919
2920 if (expr->type == EXPR_CALL)
2921 return get_sm_from_call(expr);
2922
2923 name = expr_to_known_chunk_sym(expr, &sym);
2924 if (!name)
2925 goto free;
2926
2927 ret = get_sm_state(SMATCH_EXTRA, name, sym);
2928 free:
2929 free_string(name);
2930 return ret;
2931 }
2932
2933 struct smatch_state *get_extra_state(struct expression *expr)
2934 {
2935 struct sm_state *sm;
2936
2937 sm = get_extra_sm_state(expr);
2938 if (!sm)
2939 return NULL;
2940 return sm->state;
2941 }
2942
2943 void register_smatch_extra(int id)
2944 {
2945 my_id = id;
2946
2947 set_dynamic_states(my_id);
2948 add_merge_hook(my_id, &merge_estates);
2949 add_unmatched_state_hook(my_id, &unmatched_state);
2950 select_caller_info_hook(set_param_value, PARAM_VALUE);
2951 select_caller_info_hook(set_param_fuzzy_max, FUZZY_MAX);
2952 select_caller_info_hook(set_param_hard_max, HARD_MAX);
2953 select_return_states_before(&db_limited_before);
2954 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2955 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2956 select_return_states_hook(PARAM_ADD, &db_param_add);
2957 select_return_states_hook(PARAM_SET, &db_param_set);
2958 add_lost_param_hook(&match_lost_param);
2959 select_return_states_hook(PARAM_VALUE, &db_param_value);
2960 select_return_states_after(&db_limited_after);
2961 }
2962
2963 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2964 {
2965 struct var_sym_list *links;
2966 struct var_sym *tmp;
2967 struct smatch_state *state;
2968
2969 links = sm->state->data;
2970
2971 FOR_EACH_PTR(links, tmp) {
2972 if (sm->sym == tmp->sym &&
2973 strcmp(sm->name, tmp->var) == 0)
2974 continue;
2975 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2976 if (!state)
2977 continue;
2978 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2979 } END_FOR_EACH_PTR(tmp);
2980 set_state(link_id, sm->name, sm->sym, &undefined);
2981 }
2982
2983 void register_smatch_extra_links(int id)
2984 {
2985 link_id = id;
2986 set_dynamic_states(link_id);
2987 }
2988
2989 void register_smatch_extra_late(int id)
2990 {
2991 add_merge_hook(link_id, &merge_link_states);
2992 add_modification_hook(link_id, &match_link_modify);
2993 add_hook(&match_dereferences, DEREF_HOOK);
2994 add_hook(&match_pointer_as_array, OP_HOOK);
2995 select_return_implies_hook(DEREFERENCE, &set_param_dereferenced);
2996 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2997 add_hook(&match_assign, ASSIGNMENT_HOOK);
2998 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2999 add_hook(&unop_expr, OP_HOOK);
3000 add_hook(&asm_expr, ASM_HOOK);
3001
3002 add_caller_info_callback(my_id, caller_info_callback);
3003 add_split_return_callback(&returned_struct_members);
3004
3005 // add_hook(&assume_indexes_are_valid, OP_HOOK);
3006 }
Static analysis for C