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atomic_inc_dec: add this to check_list.h
[smatch.git] / smatch_extra.c
blobce4ec4c8b89ef5710db5b4330b5a41c015bebc97
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 bool in_param_set;
195 void set_extra_mod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
196 {
197 struct expression *faked;
198
199 if (!expr)
200 expr = gen_expression_from_name_sym(name, sym);
201 remove_from_equiv(name, sym);
202 set_union_info(name, sym, expr, state);
203 mark_sub_members_gone(name, sym, state);
204 call_extra_mod_hooks(name, sym, expr, state);
205 faked = get_faked_expression();
206 if (!faked ||
207 (faked->type == EXPR_ASSIGNMENT && is_fresh_alloc(faked->right)))
208 update_mtag_data(expr, state);
209 if ((__in_fake_assign || in_param_set) &&
210 estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
211 return;
212 set_state(SMATCH_EXTRA, name, sym, state);
213 }
214
215 static void set_extra_nomod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
216 {
217 call_extra_nomod_hooks(name, sym, expr, state);
218 set_state(SMATCH_EXTRA, name, sym, state);
219 }
220
221 static char *get_pointed_at(const char *name, struct symbol *sym, struct symbol **new_sym)
222 {
223 struct expression *assigned;
224
225 /*
226 * Imagine we have an assignment: "foo = &addr;" then the other name
227 * of "*foo" is addr.
228 */
229
230 if (name[0] != '*')
231 return NULL;
232 if (strcmp(name + 1, sym->ident->name) != 0)
233 return NULL;
234
235 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
236 if (!assigned)
237 return NULL;
238 assigned = strip_parens(assigned);
239 if (assigned->type != EXPR_PREOP || assigned->op != '&')
240 return NULL;
241
242 return expr_to_var_sym(assigned->unop, new_sym);
243 }
244
245 char *get_other_name_sym_from_chunk(const char *name, const char *chunk, int len, struct symbol *sym, struct symbol **new_sym)
246 {
247 struct expression *assigned;
248 char *orig_name = NULL;
249 char buf[256];
250 char *ret;
251
252 assigned = get_assigned_expr_name_sym(chunk, sym);
253 if (!assigned)
254 return NULL;
255 if (assigned->type == EXPR_CALL)
256 return map_call_to_other_name_sym(name, sym, new_sym);
257 if (assigned->type == EXPR_PREOP && assigned->op == '&') {
258
259 orig_name = expr_to_var_sym(assigned, new_sym);
260 if (!orig_name || !*new_sym)
261 goto free;
262
263 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + len);
264 ret = alloc_string(buf);
265 free_string(orig_name);
266 return ret;
267 }
268
269 orig_name = expr_to_var_sym(assigned, new_sym);
270 if (!orig_name || !*new_sym)
271 goto free;
272
273 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + len);
274 ret = alloc_string(buf);
275 free_string(orig_name);
276 return ret;
277 free:
278 free_string(orig_name);
279 return NULL;
280 }
281
282 static char *get_long_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
283 {
284 struct expression *tmp;
285 struct sm_state *sm;
286 char buf[256];
287
288 /*
289 * Just prepend the name with a different name/sym and return that.
290 * For example, if we set "foo->bar = bar;" then the other name
291 * for "bar->baz" is "foo->bar->baz". Or if we have "foo = bar;" then
292 * the other name for "bar" is "foo". A third option is if we have
293 * "foo = bar;" then another name for "*bar" is "*foo".
294 */
295
296 FOR_EACH_MY_SM(check_assigned_expr_id, __get_cur_stree(), sm) {
297 tmp = sm->state->data;
298 if (!tmp || tmp->type != EXPR_SYMBOL)
299 continue;
300 if (tmp->symbol == sym)
301 goto found;
302 } END_FOR_EACH_SM(sm);
303
304 return NULL;
305
306 found:
307 if (!use_stack && name[tmp->symbol->ident->len] != '-')
308 return NULL;
309
310 if (name[0] == '*' && strcmp(name + 1, tmp->symbol_name->name) == 0)
311 snprintf(buf, sizeof(buf), "*%s", sm->name);
312 else if (name[tmp->symbol->ident->len] == '-' ||
313 name[tmp->symbol->ident->len] == '.')
314 snprintf(buf, sizeof(buf), "%s%s", sm->name, name + tmp->symbol->ident->len);
315 else if (strcmp(name, tmp->symbol_name->name) == 0)
316 snprintf(buf, sizeof(buf), "%s", sm->name);
317 else
318 return NULL;
319
320 *new_sym = sm->sym;
321 return alloc_string(buf);
322 }
323
324 char *get_other_name_sym_helper(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
325 {
326 char buf[256];
327 char *ret;
328 int len;
329
330 *new_sym = NULL;
331
332 if (!sym || !sym->ident)
333 return NULL;
334
335 ret = get_pointed_at(name, sym, new_sym);
336 if (ret)
337 return ret;
338
339 ret = map_long_to_short_name_sym(name, sym, new_sym, use_stack);
340 if (ret)
341 return ret;
342
343 len = snprintf(buf, sizeof(buf), "%s", name);
344 if (len >= sizeof(buf) - 2)
345 return NULL;
346
347 while (use_stack && len >= 1) {
348 if (buf[len] == '>' && buf[len - 1] == '-') {
349 len--;
350 buf[len] = '\0';
351 ret = get_other_name_sym_from_chunk(name, buf, len + 2, sym, new_sym);
352 if (ret)
353 return ret;
354 }
355 len--;
356 }
357
358 ret = get_long_name_sym(name, sym, new_sym, use_stack);
359 if (ret)
360 return ret;
361
362 return NULL;
363 }
364
365 char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
366 {
367 return get_other_name_sym_helper(name, sym, new_sym, true);
368 }
369
370 char *get_other_name_sym_nostack(const char *name, struct symbol *sym, struct symbol **new_sym)
371 {
372 return get_other_name_sym_helper(name, sym, new_sym, false);
373 }
374
375 void set_extra_mod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
376 {
377 char *new_name;
378 struct symbol *new_sym;
379
380 set_extra_mod_helper(name, sym, expr, state);
381 new_name = get_other_name_sym_nostack(name, sym, &new_sym);
382 if (new_name && new_sym)
383 set_extra_mod_helper(new_name, new_sym, NULL, state);
384 free_string(new_name);
385 }
386
387 static struct expression *chunk_get_array_base(struct expression *expr)
388 {
389 /*
390 * The problem with is_array() is that it only returns true for things
391 * like foo[1] but not for foo[1].bar.
392 *
393 */
394 expr = strip_expr(expr);
395 while (expr && expr->type == EXPR_DEREF)
396 expr = strip_expr(expr->deref);
397 return get_array_base(expr);
398 }
399
400 static int chunk_has_array(struct expression *expr)
401 {
402 return !!chunk_get_array_base(expr);
403 }
404
405 static void clear_array_states(struct expression *array)
406 {
407 struct sm_state *sm;
408
409 sm = get_sm_state_expr(link_id, array);
410 if (sm)
411 match_link_modify(sm, NULL);
412 }
413
414 static void set_extra_array_mod(struct expression *expr, struct smatch_state *state)
415 {
416 struct expression *array;
417 struct var_sym_list *vsl;
418 struct var_sym *vs;
419 char *name;
420 struct symbol *sym;
421
422 array = chunk_get_array_base(expr);
423
424 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
425 if (!name || !vsl) {
426 clear_array_states(array);
427 goto free;
428 }
429
430 FOR_EACH_PTR(vsl, vs) {
431 store_link(link_id, vs->var, vs->sym, name, sym);
432 } END_FOR_EACH_PTR(vs);
433
434 call_extra_mod_hooks(name, sym, expr, state);
435 set_state(SMATCH_EXTRA, name, sym, state);
436 free:
437 free_string(name);
438 }
439
440 void set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
441 {
442 struct symbol *sym;
443 char *name;
444
445 if (chunk_has_array(expr)) {
446 set_extra_array_mod(expr, state);
447 return;
448 }
449
450 expr = strip_expr(expr);
451 name = expr_to_var_sym(expr, &sym);
452 if (!name || !sym)
453 goto free;
454 set_extra_mod(name, sym, expr, state);
455 free:
456 free_string(name);
457 }
458
459 void set_extra_nomod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
460 {
461 char *new_name;
462 struct symbol *new_sym;
463 struct relation *rel;
464 struct smatch_state *orig_state;
465
466 orig_state = get_state(SMATCH_EXTRA, name, sym);
467
468 /* don't save unknown states if leaving it blank is the same */
469 if (!orig_state && estate_is_unknown(state))
470 return;
471
472 new_name = get_other_name_sym(name, sym, &new_sym);
473 if (new_name && new_sym)
474 set_extra_nomod_helper(new_name, new_sym, expr, state);
475 free_string(new_name);
476
477 if (!estate_related(orig_state)) {
478 set_extra_nomod_helper(name, sym, expr, state);
479 return;
480 }
481
482 set_related(state, estate_related(orig_state));
483 FOR_EACH_PTR(estate_related(orig_state), rel) {
484 struct smatch_state *estate;
485
486 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
487 if (!estate)
488 continue;
489 set_extra_nomod_helper(rel->name, rel->sym, expr, clone_estate_cast(estate_type(estate), state));
490 } END_FOR_EACH_PTR(rel);
491 }
492
493 void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct expression *expr, struct smatch_state *state)
494 {
495 struct var_sym *vs;
496
497 FOR_EACH_PTR(vsl, vs) {
498 store_link(link_id, vs->var, vs->sym, name, sym);
499 } END_FOR_EACH_PTR(vs);
500
501 set_extra_nomod(name, sym, expr, state);
502 }
503
504 /*
505 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
506 */
507 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
508 {
509 struct var_sym_list *vsl;
510 struct var_sym *vs;
511 char *name;
512 struct symbol *sym;
513
514 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
515 if (!name || !vsl)
516 goto free;
517 FOR_EACH_PTR(vsl, vs) {
518 store_link(link_id, vs->var, vs->sym, name, sym);
519 } END_FOR_EACH_PTR(vs);
520
521 set_extra_nomod(name, sym, expr, state);
522 free:
523 free_string(name);
524 }
525
526 static void set_extra_true_false(const char *name, struct symbol *sym,
527 struct smatch_state *true_state,
528 struct smatch_state *false_state)
529 {
530 char *new_name;
531 struct symbol *new_sym;
532 struct relation *rel;
533 struct smatch_state *orig_state;
534
535 if (!true_state && !false_state)
536 return;
537
538 if (in_warn_on_macro())
539 return;
540
541 new_name = get_other_name_sym(name, sym, &new_sym);
542 if (new_name && new_sym)
543 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
544 free_string(new_name);
545
546 orig_state = get_state(SMATCH_EXTRA, name, sym);
547
548 if (!estate_related(orig_state)) {
549 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
550 return;
551 }
552
553 if (true_state)
554 set_related(true_state, estate_related(orig_state));
555 if (false_state)
556 set_related(false_state, estate_related(orig_state));
557
558 FOR_EACH_PTR(estate_related(orig_state), rel) {
559 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
560 true_state, false_state);
561 } END_FOR_EACH_PTR(rel);
562 }
563
564 static void set_extra_chunk_true_false(struct expression *expr,
565 struct smatch_state *true_state,
566 struct smatch_state *false_state)
567 {
568 struct var_sym_list *vsl;
569 struct var_sym *vs;
570 struct symbol *type;
571 char *name;
572 struct symbol *sym;
573
574 if (in_warn_on_macro())
575 return;
576
577 type = get_type(expr);
578 if (!type)
579 return;
580
581 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
582 if (!name || !vsl)
583 goto free;
584 FOR_EACH_PTR(vsl, vs) {
585 store_link(link_id, vs->var, vs->sym, name, sym);
586 } END_FOR_EACH_PTR(vs);
587
588 set_true_false_states(SMATCH_EXTRA, name, sym,
589 clone_estate(true_state),
590 clone_estate(false_state));
591 free:
592 free_string(name);
593 }
594
595 static void set_extra_expr_true_false(struct expression *expr,
596 struct smatch_state *true_state,
597 struct smatch_state *false_state)
598 {
599 char *name;
600 struct symbol *sym;
601 sval_t sval;
602
603 if (!true_state && !false_state)
604 return;
605
606 if (get_value(expr, &sval))
607 return;
608
609 expr = strip_expr(expr);
610 name = expr_to_var_sym(expr, &sym);
611 if (!name || !sym) {
612 free_string(name);
613 set_extra_chunk_true_false(expr, true_state, false_state);
614 return;
615 }
616 set_extra_true_false(name, sym, true_state, false_state);
617 free_string(name);
618 }
619
620 static int get_countdown_info(struct expression *condition, struct expression **unop, int *op, sval_t *right)
621 {
622 struct expression *unop_expr;
623 int comparison;
624 sval_t limit;
625
626 right->type = &int_ctype;
627 right->value = 0;
628
629 condition = strip_expr(condition);
630
631 if (condition->type == EXPR_COMPARE) {
632 comparison = remove_unsigned_from_comparison(condition->op);
633
634 if (comparison != SPECIAL_GTE && comparison != '>')
635 return 0;
636 if (!get_value(condition->right, &limit))
637 return 0;
638
639 unop_expr = condition->left;
640 if (unop_expr->type != EXPR_PREOP && unop_expr->type != EXPR_POSTOP)
641 return 0;
642 if (unop_expr->op != SPECIAL_DECREMENT)
643 return 0;
644
645 *unop = unop_expr;
646 *op = comparison;
647 *right = limit;
648
649 return 1;
650 }
651
652 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
653 return 0;
654 if (condition->op != SPECIAL_DECREMENT)
655 return 0;
656
657 *unop = condition;
658 *op = '>';
659
660 return 1;
661 }
662
663 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
664 {
665 struct expression *iter_var;
666 struct expression *condition, *unop;
667 struct symbol *type;
668 struct sm_state *sm;
669 struct smatch_state *estate;
670 int op;
671 sval_t start, right;
672
673 right.type = &int_ctype;
674 right.value = 0;
675
676 condition = strip_expr(loop->iterator_pre_condition);
677 if (!condition)
678 return NULL;
679
680 if (!get_countdown_info(condition, &unop, &op, &right))
681 return NULL;
682
683 iter_var = unop->unop;
684
685 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
686 if (!sm)
687 return NULL;
688 if (sval_cmp(estate_min(sm->state), right) < 0)
689 return NULL;
690 start = estate_max(sm->state);
691
692 type = get_type(iter_var);
693 right = sval_cast(type, right);
694 start = sval_cast(type, start);
695
696 if (sval_cmp(start, right) <= 0)
697 return NULL;
698 if (!sval_is_max(start))
699 start.value--;
700
701 if (op == SPECIAL_GTE)
702 right.value--;
703
704 if (unop->type == EXPR_PREOP) {
705 right.value++;
706 estate = alloc_estate_range(right, start);
707 if (estate_has_hard_max(sm->state))
708 estate_set_hard_max(estate);
709 estate_copy_fuzzy_max(estate, sm->state);
710 set_extra_expr_mod(iter_var, estate);
711 }
712 if (unop->type == EXPR_POSTOP) {
713 estate = alloc_estate_range(right, start);
714 if (estate_has_hard_max(sm->state))
715 estate_set_hard_max(estate);
716 estate_copy_fuzzy_max(estate, sm->state);
717 set_extra_expr_mod(iter_var, estate);
718 }
719 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
720 }
721
722 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
723 struct expression *condition)
724 {
725 struct expression *iter_var;
726 struct sm_state *sm;
727 struct smatch_state *estate;
728 sval_t start, end, max;
729 struct symbol *type;
730 bool unknown_end = false;
731
732 iter_var = iter_expr->unop;
733 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
734 if (!sm)
735 return NULL;
736 if (!estate_get_single_value(sm->state, &start))
737 return NULL;
738 if (!get_implied_max(condition->right, &end)) {
739 end = sval_type_max(start.type);
740 unknown_end = true;
741 }
742
743 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
744 return NULL;
745
746 switch (condition->op) {
747 case SPECIAL_UNSIGNED_LT:
748 case SPECIAL_NOTEQUAL:
749 case '<':
750 if (!sval_is_min(end) && !unknown_end)
751 end.value--;
752 break;
753 case SPECIAL_UNSIGNED_LTE:
754 case SPECIAL_LTE:
755 break;
756 default:
757 return NULL;
758 }
759 if (sval_cmp(end, start) < 0)
760 return NULL;
761 type = get_type(iter_var);
762 start = sval_cast(type, start);
763 end = sval_cast(type, end);
764 estate = alloc_estate_range(start, end);
765 if (get_hard_max(condition->right, &max)) {
766 if (!get_macro_name(condition->pos))
767 estate_set_hard_max(estate);
768 if (condition->op == '<' ||
769 condition->op == SPECIAL_UNSIGNED_LT ||
770 condition->op == SPECIAL_NOTEQUAL)
771 max.value--;
772 max = sval_cast(type, max);
773 estate_set_fuzzy_max(estate, max);
774 }
775 set_extra_expr_mod(iter_var, estate);
776 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
777 }
778
779 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
780 struct expression *condition)
781 {
782 struct expression *iter_var;
783 struct sm_state *sm;
784 struct smatch_state *estate;
785 sval_t start, end;
786
787 iter_var = iter_expr->unop;
788 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
789 if (!sm)
790 return NULL;
791 if (!estate_get_single_value(sm->state, &start))
792 return NULL;
793 if (!get_implied_min(condition->right, &end))
794 end = sval_type_min(get_type(iter_var));
795 end = sval_cast(estate_type(sm->state), end);
796 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
797 return NULL;
798
799 switch (condition->op) {
800 case SPECIAL_NOTEQUAL:
801 case '>':
802 if (!sval_is_max(end))
803 end.value++;
804 break;
805 case SPECIAL_GTE:
806 break;
807 default:
808 return NULL;
809 }
810 if (sval_cmp(end, start) > 0)
811 return NULL;
812 estate = alloc_estate_range(end, start);
813 estate_set_hard_max(estate);
814 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
815 set_extra_expr_mod(iter_var, estate);
816 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
817 }
818
819 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
820 {
821 struct expression *iter_expr;
822 struct expression *condition;
823
824 if (!loop->iterator_post_statement)
825 return NULL;
826 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
827 return NULL;
828 iter_expr = loop->iterator_post_statement->expression;
829 if (!loop->iterator_pre_condition)
830 return NULL;
831 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
832 return NULL;
833 condition = loop->iterator_pre_condition;
834
835 if (iter_expr->op == SPECIAL_INCREMENT)
836 return handle_canonical_for_inc(iter_expr, condition);
837 if (iter_expr->op == SPECIAL_DECREMENT)
838 return handle_canonical_for_dec(iter_expr, condition);
839 return NULL;
840 }
841
842 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
843 {
844 struct sm_state *ret;
845
846 /*
847 * Canonical loops are a hack. The proper way to handle this is to
848 * use two passes, but unfortunately, doing two passes makes parsing
849 * code twice as slow.
850 *
851 * What we do is we set the inside state here, which overwrites whatever
852 * __extra_match_condition() does. Then we set the outside state in
853 * __extra_pre_loop_hook_after().
854 *
855 */
856 __push_fake_cur_stree();
857 if (!loop->iterator_post_statement)
858 ret = handle_canonical_while_count_down(loop);
859 else
860 ret = handle_canonical_for_loops(loop);
861 *stree = __pop_fake_cur_stree();
862 return ret;
863 }
864
865 int __iterator_unchanged(struct sm_state *sm)
866 {
867 if (!sm)
868 return 0;
869 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
870 return 1;
871 return 0;
872 }
873
874 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
875 {
876 struct expression *unop;
877 int op;
878 sval_t limit, after_value;
879
880 if (!get_countdown_info(condition, &unop, &op, &limit))
881 return;
882 after_value = estate_min(sm->state);
883 after_value.value--;
884 set_extra_mod(sm->name, sm->sym, condition->unop, alloc_estate_sval(after_value));
885 }
886
887 void __extra_pre_loop_hook_after(struct sm_state *sm,
888 struct statement *iterator,
889 struct expression *condition)
890 {
891 struct expression *iter_expr;
892 sval_t limit;
893 struct smatch_state *state;
894 sval_t end;
895
896 if (!iterator) {
897 while_count_down_after(sm, condition);
898 return;
899 }
900
901 iter_expr = iterator->expression;
902
903 if (condition->type != EXPR_COMPARE)
904 return;
905
906 if (iter_expr->op == SPECIAL_INCREMENT) {
907 if (!get_implied_value(condition->right, &end) &&
908 sval_is_max(estate_max(sm->state)))
909 limit = estate_max(sm->state);
910 else
911 limit = sval_binop(estate_max(sm->state), '+',
912 sval_type_val(estate_type(sm->state), 1));
913 } else {
914 limit = sval_binop(estate_min(sm->state), '-',
915 sval_type_val(estate_type(sm->state), 1));
916 }
917 limit = sval_cast(estate_type(sm->state), limit);
918 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
919 if (iter_expr->op == SPECIAL_INCREMENT)
920 state = alloc_estate_range(estate_min(sm->state), limit);
921 else
922 state = alloc_estate_range(limit, estate_max(sm->state));
923 } else {
924 state = alloc_estate_sval(limit);
925 }
926 if (!estate_has_hard_max(sm->state)) {
927 estate_clear_hard_max(state);
928 }
929 if (estate_has_fuzzy_max(sm->state)) {
930 sval_t hmax = estate_get_fuzzy_max(sm->state);
931 sval_t max = estate_max(sm->state);
932
933 if (sval_cmp(hmax, max) != 0)
934 estate_clear_fuzzy_max(state);
935 } else if (!estate_has_fuzzy_max(sm->state)) {
936 estate_clear_fuzzy_max(state);
937 }
938
939 set_extra_mod(sm->name, sm->sym, iter_expr, state);
940 }
941
942 static bool get_global_rl(const char *name, struct symbol *sym, struct range_list **rl)
943 {
944 struct expression *expr;
945
946 if (!sym || !(sym->ctype.modifiers & MOD_TOPLEVEL) || !sym->ident)
947 return false;
948 if (strcmp(sym->ident->name, name) != 0)
949 return false;
950
951 expr = symbol_expression(sym);
952 return get_implied_rl(expr, rl);
953 }
954
955 static struct stree *unmatched_stree;
956 static struct smatch_state *unmatched_state(struct sm_state *sm)
957 {
958 struct smatch_state *state;
959 struct range_list *rl;
960
961 if (unmatched_stree) {
962 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
963 if (state)
964 return state;
965 }
966 if (parent_is_gone_var_sym(sm->name, sm->sym))
967 return alloc_estate_empty();
968 if (get_global_rl(sm->name, sm->sym, &rl))
969 return alloc_estate_rl(rl);
970 return alloc_estate_whole(estate_type(sm->state));
971 }
972
973 static void clear_the_pointed_at(struct expression *expr)
974 {
975 struct stree *stree;
976 char *name;
977 struct symbol *sym;
978 struct sm_state *tmp;
979
980 name = expr_to_var_sym(expr, &sym);
981 if (!name || !sym)
982 goto free;
983
984 stree = __get_cur_stree();
985 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
986 if (tmp->name[0] != '*')
987 continue;
988 if (tmp->sym != sym)
989 continue;
990 if (strcmp(tmp->name + 1, name) != 0)
991 continue;
992 set_extra_mod(tmp->name, tmp->sym, expr, alloc_estate_whole(estate_type(tmp->state)));
993 } END_FOR_EACH_SM(tmp);
994
995 free:
996 free_string(name);
997 }
998
999 static int is_const_param(struct expression *expr, int param)
1000 {
1001 struct symbol *type;
1002
1003 type = get_arg_type(expr, param);
1004 if (!type)
1005 return 0;
1006 if (type->ctype.modifiers & MOD_CONST)
1007 return 1;
1008 return 0;
1009 }
1010
1011 static void match_function_call(struct expression *expr)
1012 {
1013 struct expression *arg;
1014 struct expression *tmp;
1015 int param = -1;
1016
1017 /* if we have the db this is handled in smatch_function_hooks.c */
1018 if (!option_no_db)
1019 return;
1020 if (inlinable(expr->fn))
1021 return;
1022
1023 FOR_EACH_PTR(expr->args, arg) {
1024 param++;
1025 if (is_const_param(expr->fn, param))
1026 continue;
1027 tmp = strip_expr(arg);
1028 if (tmp->type == EXPR_PREOP && tmp->op == '&')
1029 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
1030 else
1031 clear_the_pointed_at(tmp);
1032 } END_FOR_EACH_PTR(arg);
1033 }
1034
1035 int values_fit_type(struct expression *left, struct expression *right)
1036 {
1037 struct range_list *rl;
1038 struct symbol *type;
1039
1040 type = get_type(left);
1041 if (!type)
1042 return 0;
1043 get_absolute_rl(right, &rl);
1044 if (type == rl_type(rl))
1045 return 1;
1046 if (type_unsigned(type) && sval_is_negative(rl_min(rl)))
1047 return 0;
1048 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
1049 return 0;
1050 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
1051 return 0;
1052 return 1;
1053 }
1054
1055 static void save_chunk_info(struct expression *left, struct expression *right)
1056 {
1057 struct var_sym_list *vsl;
1058 struct var_sym *vs;
1059 struct expression *add_expr;
1060 struct symbol *type;
1061 sval_t sval;
1062 char *name;
1063 struct symbol *sym;
1064
1065 if (right->type != EXPR_BINOP || right->op != '-')
1066 return;
1067 if (!get_value(right->left, &sval))
1068 return;
1069 if (!expr_to_sym(right->right))
1070 return;
1071
1072 add_expr = binop_expression(left, '+', right->right);
1073 type = get_type(add_expr);
1074 if (!type)
1075 return;
1076 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
1077 if (!name || !vsl)
1078 goto free;
1079 FOR_EACH_PTR(vsl, vs) {
1080 store_link(link_id, vs->var, vs->sym, name, sym);
1081 } END_FOR_EACH_PTR(vs);
1082
1083 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
1084 free:
1085 free_string(name);
1086 }
1087
1088 static void do_array_assign(struct expression *left, int op, struct expression *right)
1089 {
1090 struct range_list *rl;
1091
1092 if (op == '=') {
1093 get_absolute_rl(right, &rl);
1094 rl = cast_rl(get_type(left), rl);
1095 } else {
1096 rl = alloc_whole_rl(get_type(left));
1097 }
1098
1099 set_extra_array_mod(left, alloc_estate_rl(rl));
1100 }
1101
1102 static void match_vanilla_assign(struct expression *left, struct expression *right)
1103 {
1104 struct range_list *orig_rl = NULL;
1105 struct range_list *rl = NULL;
1106 struct symbol *right_sym;
1107 struct symbol *left_type;
1108 struct symbol *right_type;
1109 char *right_name = NULL;
1110 struct symbol *sym;
1111 char *name;
1112 sval_t sval, max;
1113 struct smatch_state *state;
1114 int comparison;
1115
1116 if (is_struct(left))
1117 return;
1118
1119 save_chunk_info(left, right);
1120
1121 name = expr_to_var_sym(left, &sym);
1122 if (!name) {
1123 if (chunk_has_array(left))
1124 do_array_assign(left, '=', right);
1125 return;
1126 }
1127
1128 left_type = get_type(left);
1129 right_type = get_type(right);
1130
1131 right_name = expr_to_var_sym(right, &right_sym);
1132
1133 if (!__in_fake_assign &&
1134 !(right->type == EXPR_PREOP && right->op == '&') &&
1135 right_name && right_sym &&
1136 values_fit_type(left, strip_expr(right)) &&
1137 !has_symbol(right, sym)) {
1138 set_equiv(left, right);
1139 goto free;
1140 }
1141
1142 if (get_implied_value(right, &sval)) {
1143 state = alloc_estate_sval(sval_cast(left_type, sval));
1144 goto done;
1145 }
1146
1147 if (__in_fake_assign || is_fake_var(left)) {
1148 struct smatch_state *right_state;
1149 struct range_list *rl;
1150
1151 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
1152 if (right_state) {
1153 /* simple assignment */
1154 state = clone_estate(right_state);
1155 goto done;
1156 }
1157
1158 if (get_implied_rl(right, &rl)) {
1159 rl = cast_rl(left_type, rl);
1160 state = alloc_estate_rl(rl);
1161 goto done;
1162 }
1163
1164 state = alloc_estate_rl(alloc_whole_rl(left_type));
1165 goto done;
1166 }
1167
1168 comparison = get_comparison_no_extra(left, right);
1169 if (comparison) {
1170 comparison = flip_comparison(comparison);
1171 get_implied_rl(left, &orig_rl);
1172 }
1173
1174 if (get_implied_rl(right, &rl)) {
1175 rl = cast_rl(left_type, rl);
1176 if (orig_rl)
1177 filter_by_comparison(&rl, comparison, orig_rl);
1178 state = alloc_estate_rl(rl);
1179 if (get_hard_max(right, &max)) {
1180 estate_set_hard_max(state);
1181 estate_set_fuzzy_max(state, max);
1182 }
1183 } else {
1184 rl = alloc_whole_rl(right_type);
1185 rl = cast_rl(left_type, rl);
1186 if (orig_rl)
1187 filter_by_comparison(&rl, comparison, orig_rl);
1188 state = alloc_estate_rl(rl);
1189 }
1190
1191 done:
1192 set_extra_mod(name, sym, left, state);
1193 free:
1194 free_string(right_name);
1195 }
1196
1197 static void match_assign(struct expression *expr)
1198 {
1199 struct range_list *rl = NULL;
1200 struct expression *left;
1201 struct expression *right;
1202 struct expression *binop_expr;
1203 struct symbol *left_type;
1204 struct symbol *sym;
1205 char *name;
1206
1207 left = strip_expr(expr->left);
1208
1209 right = strip_parens(expr->right);
1210 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
1211 right = get_argument_from_call_expr(right->args, 0);
1212 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
1213 right = strip_parens(right->left);
1214
1215 if (expr->op == '=' && is_condition(expr->right))
1216 return; /* handled in smatch_condition.c */
1217 if (expr->op == '=' && right->type == EXPR_CALL &&
1218 !is_fake_call(right))
1219 return; /* handled in smatch_function_hooks.c */
1220 if (expr->op == '=') {
1221 match_vanilla_assign(left, right);
1222 return;
1223 }
1224
1225 name = expr_to_var_sym(left, &sym);
1226 if (!name)
1227 return;
1228
1229 left_type = get_type(left);
1230
1231 switch (expr->op) {
1232 case SPECIAL_ADD_ASSIGN:
1233 case SPECIAL_SUB_ASSIGN:
1234 case SPECIAL_AND_ASSIGN:
1235 case SPECIAL_MOD_ASSIGN:
1236 case SPECIAL_SHL_ASSIGN:
1237 case SPECIAL_SHR_ASSIGN:
1238 case SPECIAL_OR_ASSIGN:
1239 case SPECIAL_XOR_ASSIGN:
1240 case SPECIAL_MUL_ASSIGN:
1241 case SPECIAL_DIV_ASSIGN:
1242 binop_expr = binop_expression(expr->left,
1243 op_remove_assign(expr->op),
1244 expr->right);
1245 get_absolute_rl(binop_expr, &rl);
1246 rl = cast_rl(left_type, rl);
1247 if (inside_loop()) {
1248 if (expr->op == SPECIAL_ADD_ASSIGN)
1249 add_range(&rl, rl_max(rl), sval_type_max(rl_type(rl)));
1250
1251 if (expr->op == SPECIAL_SUB_ASSIGN &&
1252 !sval_is_negative(rl_min(rl))) {
1253 sval_t zero = { .type = rl_type(rl) };
1254
1255 add_range(&rl, rl_min(rl), zero);
1256 }
1257 }
1258 set_extra_mod(name, sym, left, alloc_estate_rl(rl));
1259 goto free;
1260 }
1261 set_extra_mod(name, sym, left, alloc_estate_whole(left_type));
1262 free:
1263 free_string(name);
1264 }
1265
1266 static struct smatch_state *increment_state(struct smatch_state *state)
1267 {
1268 sval_t min = estate_min(state);
1269 sval_t max = estate_max(state);
1270
1271 if (!estate_rl(state))
1272 return NULL;
1273
1274 if (inside_loop())
1275 max = sval_type_max(max.type);
1276
1277 if (!sval_is_min(min) && !sval_is_max(min))
1278 min.value++;
1279 if (!sval_is_min(max) && !sval_is_max(max))
1280 max.value++;
1281 return alloc_estate_range(min, max);
1282 }
1283
1284 static struct smatch_state *decrement_state(struct smatch_state *state)
1285 {
1286 sval_t min = estate_min(state);
1287 sval_t max = estate_max(state);
1288
1289 if (!estate_rl(state))
1290 return NULL;
1291
1292 if (inside_loop())
1293 min = sval_type_min(min.type);
1294
1295 if (!sval_is_min(min) && !sval_is_max(min))
1296 min.value--;
1297 if (!sval_is_min(max) && !sval_is_max(max))
1298 max.value--;
1299 return alloc_estate_range(min, max);
1300 }
1301
1302 static void clear_pointed_at_state(struct expression *expr)
1303 {
1304 struct symbol *type;
1305
1306 /*
1307 * ALERT: This is sort of a mess. If it's is a struct assigment like
1308 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1309 * the same thing for p++ where "p" is a struct. Most modifications
1310 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1311 * use smatch_modification.c because we have to get the ordering right
1312 * or something. So if you have p++ where p is a pointer to a standard
1313 * c type then we handle that here. What a mess.
1314 */
1315 expr = strip_expr(expr);
1316 type = get_type(expr);
1317 if (!type || type->type != SYM_PTR)
1318 return;
1319 type = get_real_base_type(type);
1320 if (!type || type->type != SYM_BASETYPE)
1321 return;
1322 set_extra_expr_nomod(deref_expression(expr), alloc_estate_whole(type));
1323 }
1324
1325 static void unop_expr(struct expression *expr)
1326 {
1327 struct smatch_state *state;
1328
1329 if (expr->smatch_flags & Handled)
1330 return;
1331
1332 switch (expr->op) {
1333 case SPECIAL_INCREMENT:
1334 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1335 state = increment_state(state);
1336 if (!state)
1337 state = alloc_estate_whole(get_type(expr));
1338 set_extra_expr_mod(expr->unop, state);
1339 clear_pointed_at_state(expr->unop);
1340 break;
1341 case SPECIAL_DECREMENT:
1342 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1343 state = decrement_state(state);
1344 if (!state)
1345 state = alloc_estate_whole(get_type(expr));
1346 set_extra_expr_mod(expr->unop, state);
1347 clear_pointed_at_state(expr->unop);
1348 break;
1349 default:
1350 return;
1351 }
1352 }
1353
1354 static void asm_expr(struct statement *stmt)
1355 {
1356 struct asm_operand *op;
1357 struct symbol *type;
1358
1359 FOR_EACH_PTR(stmt->asm_outputs, op) {
1360 type = get_type(strip_expr(op->expr));
1361 set_extra_expr_mod(op->expr, alloc_estate_whole(type));
1362 } END_FOR_EACH_PTR(op);
1363 }
1364
1365 static void check_dereference(struct expression *expr)
1366 {
1367 struct smatch_state *state;
1368
1369 if (__in_fake_assign)
1370 return;
1371 if (outside_of_function())
1372 return;
1373 state = get_extra_state(expr);
1374 if (state) {
1375 struct range_list *rl;
1376
1377 rl = rl_intersection(estate_rl(state), valid_ptr_rl);
1378 if (rl_equiv(rl, estate_rl(state)))
1379 return;
1380 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1381 } else {
1382 struct range_list *rl;
1383
1384 if (get_mtag_rl(expr, &rl))
1385 rl = rl_intersection(rl, valid_ptr_rl);
1386 else
1387 rl = clone_rl(valid_ptr_rl);
1388
1389 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1390 }
1391 }
1392
1393 static void match_dereferences(struct expression *expr)
1394 {
1395 if (expr->type != EXPR_PREOP)
1396 return;
1397 if (getting_address(expr))
1398 return;
1399 /* it's saying that foo[1] = bar dereferences foo[1] */
1400 if (is_array(expr))
1401 return;
1402 check_dereference(expr->unop);
1403 }
1404
1405 static void match_pointer_as_array(struct expression *expr)
1406 {
1407 if (!is_array(expr))
1408 return;
1409 check_dereference(get_array_base(expr));
1410 }
1411
1412 static void find_dereferences(struct expression *expr)
1413 {
1414 while (expr->type == EXPR_PREOP) {
1415 if (expr->op == '*')
1416 check_dereference(expr->unop);
1417 expr = strip_expr(expr->unop);
1418 }
1419 }
1420
1421 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
1422 {
1423 struct symbol *sym;
1424 char *name;
1425
1426 name = get_variable_from_key(arg, key, &sym);
1427 if (name && sym) {
1428 struct smatch_state *orig, *new;
1429 struct range_list *rl;
1430
1431 orig = get_state(SMATCH_EXTRA, name, sym);
1432 if (orig) {
1433 rl = rl_intersection(estate_rl(orig),
1434 alloc_rl(valid_ptr_min_sval,
1435 valid_ptr_max_sval));
1436 new = alloc_estate_rl(rl);
1437 } else {
1438 new = alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval);
1439 }
1440
1441 set_extra_nomod(name, sym, NULL, new);
1442 }
1443 free_string(name);
1444
1445 find_dereferences(arg);
1446 }
1447
1448 static sval_t add_one(sval_t sval)
1449 {
1450 sval.value++;
1451 return sval;
1452 }
1453
1454 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1455 {
1456 struct statement *stmt;
1457 struct expression *cond;
1458 struct smatch_state *true_state, *false_state;
1459 struct symbol *type;
1460 sval_t start;
1461 sval_t limit;
1462
1463 /*
1464 * If we're decrementing here then that's a canonical while count down
1465 * so it's handled already. We're only handling loops like:
1466 * i = 0;
1467 * do { ... } while (i++ < 3);
1468 */
1469
1470 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1471 return 0;
1472
1473 stmt = __cur_stmt->parent;
1474 if (!stmt)
1475 return 0;
1476 if (stmt->type == STMT_COMPOUND)
1477 stmt = stmt->parent;
1478 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1479 return 0;
1480
1481 cond = strip_expr(stmt->iterator_post_condition);
1482 if (cond->type != EXPR_COMPARE || cond->op != op)
1483 return 0;
1484 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1485 return 0;
1486
1487 if (!get_implied_value(left->unop, &start))
1488 return 0;
1489 if (!get_implied_value(right, &limit))
1490 return 0;
1491 type = get_type(left->unop);
1492 limit = sval_cast(type, limit);
1493 if (sval_cmp(start, limit) > 0)
1494 return 0;
1495
1496 switch (op) {
1497 case '<':
1498 case SPECIAL_UNSIGNED_LT:
1499 break;
1500 case SPECIAL_LTE:
1501 case SPECIAL_UNSIGNED_LTE:
1502 limit = add_one(limit);
1503 default:
1504 return 0;
1505
1506 }
1507
1508 true_state = alloc_estate_range(add_one(start), limit);
1509 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1510
1511 /* Currently we just discard the false state but when two passes is
1512 * implimented correctly then it will use it.
1513 */
1514
1515 set_extra_expr_true_false(left->unop, true_state, false_state);
1516
1517 return 1;
1518 }
1519
1520 bool is_impossible_variable(struct expression *expr)
1521 {
1522 struct smatch_state *state;
1523
1524 state = get_extra_state(expr);
1525 if (state && !estate_rl(state))
1526 return true;
1527 return false;
1528 }
1529
1530 static bool in_macro(struct expression *left, struct expression *right)
1531 {
1532 if (!left || !right)
1533 return 0;
1534 if (left->pos.line != right->pos.line || left->pos.pos != right->pos.pos)
1535 return 0;
1536 if (get_macro_name(left->pos))
1537 return 1;
1538 return 0;
1539 }
1540
1541 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1542 {
1543 struct range_list *left_orig;
1544 struct range_list *left_true;
1545 struct range_list *left_false;
1546 struct range_list *right_orig;
1547 struct range_list *right_true;
1548 struct range_list *right_false;
1549 struct smatch_state *left_true_state;
1550 struct smatch_state *left_false_state;
1551 struct smatch_state *right_true_state;
1552 struct smatch_state *right_false_state;
1553 sval_t dummy, hard_max;
1554 int left_postop = 0;
1555 int right_postop = 0;
1556
1557 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1558 if (left->type == EXPR_POSTOP) {
1559 left->smatch_flags |= Handled;
1560 left_postop = left->op;
1561 if (handle_postop_inc(left, op, right))
1562 return;
1563 }
1564 left = strip_parens(left->unop);
1565 }
1566 while (left->type == EXPR_ASSIGNMENT)
1567 left = strip_parens(left->left);
1568
1569 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1570 if (right->type == EXPR_POSTOP) {
1571 right->smatch_flags |= Handled;
1572 right_postop = right->op;
1573 }
1574 right = strip_parens(right->unop);
1575 }
1576
1577 if (is_impossible_variable(left) || is_impossible_variable(right))
1578 return;
1579
1580 get_real_absolute_rl(left, &left_orig);
1581 left_orig = cast_rl(type, left_orig);
1582
1583 get_real_absolute_rl(right, &right_orig);
1584 right_orig = cast_rl(type, right_orig);
1585
1586 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1587
1588 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1589 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1590 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1591 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1592
1593 if (!left_true || !left_false) {
1594 struct range_list *tmp_true, *tmp_false;
1595
1596 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1597 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1598 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1599 if (tmp_true && tmp_false)
1600 __save_imaginary_state(left, tmp_true, tmp_false);
1601 }
1602
1603 if (!right_true || !right_false) {
1604 struct range_list *tmp_true, *tmp_false;
1605
1606 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1607 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1608 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1609 if (tmp_true && tmp_false)
1610 __save_imaginary_state(right, tmp_true, tmp_false);
1611 }
1612
1613 left_true_state = alloc_estate_rl(left_true);
1614 left_false_state = alloc_estate_rl(left_false);
1615 right_true_state = alloc_estate_rl(right_true);
1616 right_false_state = alloc_estate_rl(right_false);
1617
1618 switch (op) {
1619 case '<':
1620 case SPECIAL_UNSIGNED_LT:
1621 case SPECIAL_UNSIGNED_LTE:
1622 case SPECIAL_LTE:
1623 if (get_hard_max(right, &dummy) && !in_macro(left, right))
1624 estate_set_hard_max(left_true_state);
1625 if (get_hard_max(left, &dummy) && !in_macro(left, right))
1626 estate_set_hard_max(right_false_state);
1627 break;
1628 case '>':
1629 case SPECIAL_UNSIGNED_GT:
1630 case SPECIAL_UNSIGNED_GTE:
1631 case SPECIAL_GTE:
1632 if (get_hard_max(left, &dummy) && !in_macro(left, right))
1633 estate_set_hard_max(right_true_state);
1634 if (get_hard_max(right, &dummy) && !in_macro(left, right))
1635 estate_set_hard_max(left_false_state);
1636 break;
1637 }
1638
1639 switch (op) {
1640 case '<':
1641 case SPECIAL_UNSIGNED_LT:
1642 case SPECIAL_UNSIGNED_LTE:
1643 case SPECIAL_LTE:
1644 if (get_hard_max(right, &hard_max)) {
1645 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1646 hard_max.value--;
1647 estate_set_fuzzy_max(left_true_state, hard_max);
1648 }
1649 if (get_implied_value(right, &hard_max)) {
1650 if (op == SPECIAL_UNSIGNED_LTE ||
1651 op == SPECIAL_LTE)
1652 hard_max.value++;
1653 estate_set_fuzzy_max(left_false_state, hard_max);
1654 }
1655 if (get_hard_max(left, &hard_max)) {
1656 if (op == SPECIAL_UNSIGNED_LTE ||
1657 op == SPECIAL_LTE)
1658 hard_max.value--;
1659 estate_set_fuzzy_max(right_false_state, hard_max);
1660 }
1661 if (get_implied_value(left, &hard_max)) {
1662 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1663 hard_max.value++;
1664 estate_set_fuzzy_max(right_true_state, hard_max);
1665 }
1666 break;
1667 case '>':
1668 case SPECIAL_UNSIGNED_GT:
1669 case SPECIAL_UNSIGNED_GTE:
1670 case SPECIAL_GTE:
1671 if (get_hard_max(left, &hard_max)) {
1672 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1673 hard_max.value--;
1674 estate_set_fuzzy_max(right_true_state, hard_max);
1675 }
1676 if (get_implied_value(left, &hard_max)) {
1677 if (op == SPECIAL_UNSIGNED_GTE ||
1678 op == SPECIAL_GTE)
1679 hard_max.value++;
1680 estate_set_fuzzy_max(right_false_state, hard_max);
1681 }
1682 if (get_hard_max(right, &hard_max)) {
1683 if (op == SPECIAL_UNSIGNED_LTE ||
1684 op == SPECIAL_LTE)
1685 hard_max.value--;
1686 estate_set_fuzzy_max(left_false_state, hard_max);
1687 }
1688 if (get_implied_value(right, &hard_max)) {
1689 if (op == '>' ||
1690 op == SPECIAL_UNSIGNED_GT)
1691 hard_max.value++;
1692 estate_set_fuzzy_max(left_true_state, hard_max);
1693 }
1694 break;
1695 case SPECIAL_EQUAL:
1696 if (get_hard_max(left, &hard_max))
1697 estate_set_fuzzy_max(right_true_state, hard_max);
1698 if (get_hard_max(right, &hard_max))
1699 estate_set_fuzzy_max(left_true_state, hard_max);
1700 break;
1701 }
1702
1703 if (get_hard_max(left, &hard_max)) {
1704 estate_set_hard_max(left_true_state);
1705 estate_set_hard_max(left_false_state);
1706 }
1707 if (get_hard_max(right, &hard_max)) {
1708 estate_set_hard_max(right_true_state);
1709 estate_set_hard_max(right_false_state);
1710 }
1711
1712 if (left_postop == SPECIAL_INCREMENT) {
1713 left_true_state = increment_state(left_true_state);
1714 left_false_state = increment_state(left_false_state);
1715 }
1716 if (left_postop == SPECIAL_DECREMENT) {
1717 left_true_state = decrement_state(left_true_state);
1718 left_false_state = decrement_state(left_false_state);
1719 }
1720 if (right_postop == SPECIAL_INCREMENT) {
1721 right_true_state = increment_state(right_true_state);
1722 right_false_state = increment_state(right_false_state);
1723 }
1724 if (right_postop == SPECIAL_DECREMENT) {
1725 right_true_state = decrement_state(right_true_state);
1726 right_false_state = decrement_state(right_false_state);
1727 }
1728
1729 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1730 left_true_state = NULL;
1731 left_false_state = NULL;
1732 }
1733
1734 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1735 right_true_state = NULL;
1736 right_false_state = NULL;
1737 }
1738
1739 /* Don't introduce new states for known true/false conditions */
1740 if (rl_equiv(left_orig, estate_rl(left_true_state)))
1741 left_true_state = NULL;
1742 if (rl_equiv(left_orig, estate_rl(left_false_state)))
1743 left_false_state = NULL;
1744 if (rl_equiv(right_orig, estate_rl(right_true_state)))
1745 right_true_state = NULL;
1746 if (rl_equiv(right_orig, estate_rl(right_false_state)))
1747 right_false_state = NULL;
1748
1749 set_extra_expr_true_false(left, left_true_state, left_false_state);
1750 set_extra_expr_true_false(right, right_true_state, right_false_state);
1751 }
1752
1753 static int is_simple_math(struct expression *expr)
1754 {
1755 if (!expr)
1756 return 0;
1757 if (expr->type != EXPR_BINOP)
1758 return 0;
1759 switch (expr->op) {
1760 case '+':
1761 case '-':
1762 case '*':
1763 return 1;
1764 }
1765 return 0;
1766 }
1767
1768 static int flip_op(int op)
1769 {
1770 /* We only care about simple math */
1771 switch (op) {
1772 case '+':
1773 return '-';
1774 case '-':
1775 return '+';
1776 case '*':
1777 return '/';
1778 }
1779 return 0;
1780 }
1781
1782 static void move_known_to_rl(struct expression **expr_p, struct range_list **rl_p)
1783 {
1784 struct expression *expr = *expr_p;
1785 struct range_list *rl = *rl_p;
1786 sval_t sval;
1787
1788 if (!is_simple_math(expr))
1789 return;
1790
1791 if (get_implied_value(expr->right, &sval)) {
1792 *expr_p = expr->left;
1793 *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
1794 move_known_to_rl(expr_p, rl_p);
1795 return;
1796 }
1797 if (expr->op == '-')
1798 return;
1799 if (get_implied_value(expr->left, &sval)) {
1800 *expr_p = expr->right;
1801 *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
1802 move_known_to_rl(expr_p, rl_p);
1803 return;
1804 }
1805 }
1806
1807 static void move_known_values(struct expression **left_p, struct expression **right_p)
1808 {
1809 struct expression *left = *left_p;
1810 struct expression *right = *right_p;
1811 sval_t sval, dummy;
1812
1813 if (get_implied_value(left, &sval)) {
1814 if (!is_simple_math(right))
1815 return;
1816 if (get_implied_value(right, &dummy))
1817 return;
1818 if (right->op == '*') {
1819 sval_t divisor;
1820
1821 if (!get_value(right->right, &divisor))
1822 return;
1823 if (divisor.value == 0)
1824 return;
1825 *left_p = binop_expression(left, invert_op(right->op), right->right);
1826 *right_p = right->left;
1827 return;
1828 }
1829 if (right->op == '+' && get_value(right->left, &sval)) {
1830 *left_p = binop_expression(left, invert_op(right->op), right->left);
1831 *right_p = right->right;
1832 return;
1833 }
1834 if (get_value(right->right, &sval)) {
1835 *left_p = binop_expression(left, invert_op(right->op), right->right);
1836 *right_p = right->left;
1837 return;
1838 }
1839 return;
1840 }
1841 if (get_implied_value(right, &sval)) {
1842 if (!is_simple_math(left))
1843 return;
1844 if (get_implied_value(left, &dummy))
1845 return;
1846 if (left->op == '*') {
1847 sval_t divisor;
1848
1849 if (!get_value(left->right, &divisor))
1850 return;
1851 if (divisor.value == 0)
1852 return;
1853 *right_p = binop_expression(right, invert_op(left->op), left->right);
1854 *left_p = left->left;
1855 return;
1856 }
1857 if (left->op == '+' && get_value(left->left, &sval)) {
1858 *right_p = binop_expression(right, invert_op(left->op), left->left);
1859 *left_p = left->right;
1860 return;
1861 }
1862
1863 if (get_value(left->right, &sval)) {
1864 *right_p = binop_expression(right, invert_op(left->op), left->right);
1865 *left_p = left->left;
1866 return;
1867 }
1868 return;
1869 }
1870 }
1871
1872 /*
1873 * The reason for do_simple_algebra() is to solve things like:
1874 * if (foo > 66 || foo + bar > 64) {
1875 * "foo" is not really a known variable so it won't be handled by
1876 * move_known_variables() but it's a super common idiom.
1877 *
1878 */
1879 static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
1880 {
1881 struct expression *left = *left_p;
1882 struct expression *right = *right_p;
1883 struct range_list *rl;
1884 sval_t tmp;
1885
1886 if (left->type != EXPR_BINOP || left->op != '+')
1887 return 0;
1888 if (can_integer_overflow(get_type(left), left))
1889 return 0;
1890 if (!get_implied_value(right, &tmp))
1891 return 0;
1892
1893 if (!get_implied_value(left->left, &tmp) &&
1894 get_implied_rl(left->left, &rl) &&
1895 !is_whole_rl(rl)) {
1896 *right_p = binop_expression(right, '-', left->left);
1897 *left_p = left->right;
1898 return 1;
1899 }
1900 if (!get_implied_value(left->right, &tmp) &&
1901 get_implied_rl(left->right, &rl) &&
1902 !is_whole_rl(rl)) {
1903 *right_p = binop_expression(right, '-', left->right);
1904 *left_p = left->left;
1905 return 1;
1906 }
1907
1908 return 0;
1909 }
1910
1911 static int match_func_comparison(struct expression *expr)
1912 {
1913 struct expression *left = strip_expr(expr->left);
1914 struct expression *right = strip_expr(expr->right);
1915
1916 if (left->type == EXPR_CALL || right->type == EXPR_CALL) {
1917 function_comparison(left, expr->op, right);
1918 return 1;
1919 }
1920
1921 return 0;
1922 }
1923
1924 /* Handle conditions like "if (foo + bar < foo) {" */
1925 static int handle_integer_overflow_test(struct expression *expr)
1926 {
1927 struct expression *left, *right;
1928 struct symbol *type;
1929 sval_t left_min, right_min, min, max;
1930
1931 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
1932 return 0;
1933
1934 left = strip_parens(expr->left);
1935 right = strip_parens(expr->right);
1936
1937 if (left->op != '+')
1938 return 0;
1939
1940 type = get_type(expr);
1941 if (!type)
1942 return 0;
1943 if (type_positive_bits(type) == 32) {
1944 max.type = &uint_ctype;
1945 max.uvalue = (unsigned int)-1;
1946 } else if (type_positive_bits(type) == 64) {
1947 max.type = &ulong_ctype;
1948 max.value = (unsigned long long)-1;
1949 } else {
1950 return 0;
1951 }
1952
1953 if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
1954 return 0;
1955
1956 get_absolute_min(left->left, &left_min);
1957 get_absolute_min(left->right, &right_min);
1958 min = sval_binop(left_min, '+', right_min);
1959
1960 type = get_type(left);
1961 min = sval_cast(type, min);
1962 max = sval_cast(type, max);
1963
1964 set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
1965 return 1;
1966 }
1967
1968 static void match_comparison(struct expression *expr)
1969 {
1970 struct expression *left_orig = strip_parens(expr->left);
1971 struct expression *right_orig = strip_parens(expr->right);
1972 struct expression *left, *right, *tmp;
1973 struct expression *prev;
1974 struct symbol *type;
1975 int redo, count;
1976
1977 if (match_func_comparison(expr))
1978 return;
1979
1980 type = get_type(expr);
1981 if (!type)
1982 type = &llong_ctype;
1983
1984 if (handle_integer_overflow_test(expr))
1985 return;
1986
1987 left = left_orig;
1988 right = right_orig;
1989 move_known_values(&left, &right);
1990 handle_comparison(type, left, expr->op, right);
1991
1992 left = left_orig;
1993 right = right_orig;
1994 if (do_simple_algebra(&left, &right))
1995 handle_comparison(type, left, expr->op, right);
1996
1997 prev = get_assigned_expr(left_orig);
1998 if (is_simple_math(prev) && !has_variable(prev, left_orig)) {
1999 left = prev;
2000 right = right_orig;
2001 move_known_values(&left, &right);
2002 handle_comparison(type, left, expr->op, right);
2003 }
2004
2005 prev = get_assigned_expr(right_orig);
2006 if (is_simple_math(prev) && !has_variable(prev, right_orig)) {
2007 left = left_orig;
2008 right = prev;
2009 move_known_values(&left, &right);
2010 handle_comparison(type, left, expr->op, right);
2011 }
2012
2013 redo = 0;
2014 left = left_orig;
2015 right = right_orig;
2016 if (get_last_expr_from_expression_stmt(left_orig)) {
2017 left = get_last_expr_from_expression_stmt(left_orig);
2018 redo = 1;
2019 }
2020 if (get_last_expr_from_expression_stmt(right_orig)) {
2021 right = get_last_expr_from_expression_stmt(right_orig);
2022 redo = 1;
2023 }
2024
2025 if (!redo)
2026 return;
2027
2028 count = 0;
2029 while ((tmp = get_assigned_expr(left))) {
2030 if (count++ > 3)
2031 break;
2032 left = strip_expr(tmp);
2033 }
2034 count = 0;
2035 while ((tmp = get_assigned_expr(right))) {
2036 if (count++ > 3)
2037 break;
2038 right = strip_expr(tmp);
2039 }
2040
2041 handle_comparison(type, left, expr->op, right);
2042 }
2043
2044 static sval_t get_high_mask(sval_t known)
2045 {
2046 sval_t ret;
2047 int i;
2048
2049 ret = known;
2050 ret.value = 0;
2051
2052 for (i = type_bits(known.type) - 1; i >= 0; i--) {
2053 if (known.uvalue & (1ULL << i))
2054 ret.uvalue |= (1ULL << i);
2055 else
2056 return ret;
2057
2058 }
2059 return ret;
2060 }
2061
2062 static bool handle_bit_test(struct expression *expr)
2063 {
2064 struct range_list *orig_rl, *rl;
2065 struct expression *shift, *mask, *var;
2066 struct bit_info *bit_info;
2067 sval_t sval;
2068 sval_t high = { .type = &int_ctype };
2069 sval_t low = { .type = &int_ctype };
2070
2071 shift = strip_expr(expr->right);
2072 mask = strip_expr(expr->left);
2073 if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT) {
2074 shift = strip_expr(expr->left);
2075 mask = strip_expr(expr->right);
2076 if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT)
2077 return false;
2078 }
2079 if (!get_implied_value(shift->left, &sval) || sval.value != 1)
2080 return false;
2081 var = strip_expr(shift->right);
2082
2083 bit_info = get_bit_info(mask);
2084 if (!bit_info)
2085 return false;
2086 if (!bit_info->possible)
2087 return false;
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);
2095 high.value = sm_fls64(bit_info->possible);
2096 rl = alloc_rl(low, high);
2097 rl = cast_rl(get_type(var), rl);
2098 rl = rl_intersection(orig_rl, rl);
2099 if (!rl)
2100 return false;
2101
2102 set_extra_expr_true_false(shift->right, alloc_estate_rl(rl), NULL);
2103
2104 return true;
2105 }
2106
2107 static void handle_AND_op(struct expression *var, sval_t known)
2108 {
2109 struct range_list *orig_rl;
2110 struct range_list *true_rl = NULL;
2111 struct range_list *false_rl = NULL;
2112 int bit;
2113 sval_t low_mask = known;
2114 sval_t high_mask;
2115 sval_t max;
2116
2117 get_absolute_rl(var, &orig_rl);
2118
2119 if (known.value > 0) {
2120 bit = ffsll(known.value) - 1;
2121 low_mask.uvalue = (1ULL << bit) - 1;
2122 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
2123 }
2124 high_mask = get_high_mask(known);
2125 if (high_mask.value) {
2126 bit = ffsll(high_mask.value) - 1;
2127 low_mask.uvalue = (1ULL << bit) - 1;
2128
2129 false_rl = orig_rl;
2130 if (sval_is_negative(rl_min(orig_rl)))
2131 false_rl = remove_range(false_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
2132 false_rl = remove_range(false_rl, low_mask, sval_type_max(known.type));
2133 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
2134 false_rl = remove_range(false_rl,
2135 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
2136 sval_type_val(rl_type(false_rl), -1));
2137 }
2138 } else if (known.value == 1 &&
2139 get_hard_max(var, &max) &&
2140 sval_cmp(max, rl_max(orig_rl)) == 0 &&
2141 max.value & 1) {
2142 false_rl = remove_range(orig_rl, max, max);
2143 }
2144 set_extra_expr_true_false(var,
2145 true_rl ? alloc_estate_rl(true_rl) : NULL,
2146 false_rl ? alloc_estate_rl(false_rl) : NULL);
2147 }
2148
2149 static void handle_AND_condition(struct expression *expr)
2150 {
2151 sval_t known;
2152
2153 if (handle_bit_test(expr))
2154 return;
2155
2156 if (get_implied_value(expr->left, &known))
2157 handle_AND_op(expr->right, known);
2158 else if (get_implied_value(expr->right, &known))
2159 handle_AND_op(expr->left, known);
2160 }
2161
2162 static void handle_MOD_condition(struct expression *expr)
2163 {
2164 struct range_list *orig_rl;
2165 struct range_list *true_rl;
2166 struct range_list *false_rl = NULL;
2167 sval_t right;
2168 sval_t zero = {
2169 .value = 0,
2170 };
2171
2172 if (!get_implied_value(expr->right, &right) || right.value == 0)
2173 return;
2174 get_absolute_rl(expr->left, &orig_rl);
2175
2176 zero.type = rl_type(orig_rl);
2177
2178 /* We're basically dorking around the min and max here */
2179 true_rl = remove_range(orig_rl, zero, zero);
2180 if (!sval_is_max(rl_max(true_rl)) &&
2181 !(rl_max(true_rl).value % right.value))
2182 true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));
2183
2184 if (rl_equiv(true_rl, orig_rl))
2185 true_rl = NULL;
2186
2187 if (sval_is_positive(rl_min(orig_rl)) &&
2188 (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
2189 sval_t add;
2190 int i;
2191
2192 add = rl_min(orig_rl);
2193 add.value += right.value - (add.value % right.value);
2194 add.value -= right.value;
2195
2196 for (i = 0; i < 5; i++) {
2197 add.value += right.value;
2198 if (add.value > rl_max(orig_rl).value)
2199 break;
2200 add_range(&false_rl, add, add);
2201 }
2202 } else {
2203 if (rl_min(orig_rl).uvalue != 0 &&
2204 rl_min(orig_rl).uvalue < right.uvalue) {
2205 sval_t chop = right;
2206 chop.value--;
2207 false_rl = remove_range(orig_rl, zero, chop);
2208 }
2209
2210 if (!sval_is_max(rl_max(orig_rl)) &&
2211 (rl_max(orig_rl).value % right.value)) {
2212 sval_t chop = rl_max(orig_rl);
2213 chop.value -= chop.value % right.value;
2214 chop.value++;
2215 if (!false_rl)
2216 false_rl = clone_rl(orig_rl);
2217 false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
2218 }
2219 }
2220
2221 set_extra_expr_true_false(expr->left,
2222 true_rl ? alloc_estate_rl(true_rl) : NULL,
2223 false_rl ? alloc_estate_rl(false_rl) : NULL);
2224 }
2225
2226 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
2227 void __extra_match_condition(struct expression *expr)
2228 {
2229 expr = strip_expr(expr);
2230 switch (expr->type) {
2231 case EXPR_CALL:
2232 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
2233 return;
2234 case EXPR_PREOP:
2235 case EXPR_SYMBOL:
2236 case EXPR_DEREF:
2237 handle_comparison(get_type(expr), expr, SPECIAL_NOTEQUAL, zero_expr());
2238 return;
2239 case EXPR_COMPARE:
2240 match_comparison(expr);
2241 return;
2242 case EXPR_ASSIGNMENT:
2243 __extra_match_condition(expr->left);
2244 return;
2245 case EXPR_BINOP:
2246 if (expr->op == '&')
2247 handle_AND_condition(expr);
2248 if (expr->op == '%')
2249 handle_MOD_condition(expr);
2250 return;
2251 }
2252 }
2253
2254 static void assume_indexes_are_valid(struct expression *expr)
2255 {
2256 struct expression *array_expr;
2257 int array_size;
2258 struct expression *offset;
2259 struct symbol *offset_type;
2260 struct range_list *rl_before;
2261 struct range_list *rl_after;
2262 struct range_list *filter = NULL;
2263 sval_t size;
2264
2265 expr = strip_expr(expr);
2266 if (!is_array(expr))
2267 return;
2268
2269 offset = get_array_offset(expr);
2270 offset_type = get_type(offset);
2271 if (offset_type && type_signed(offset_type)) {
2272 filter = alloc_rl(sval_type_min(offset_type),
2273 sval_type_val(offset_type, -1));
2274 }
2275
2276 array_expr = get_array_base(expr);
2277 array_size = get_real_array_size(array_expr);
2278 if (array_size > 1) {
2279 size = sval_type_val(offset_type, array_size);
2280 add_range(&filter, size, sval_type_max(offset_type));
2281 }
2282
2283 if (!filter)
2284 return;
2285 get_absolute_rl(offset, &rl_before);
2286 rl_after = rl_filter(rl_before, filter);
2287 if (rl_equiv(rl_before, rl_after))
2288 return;
2289 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
2290 }
2291
2292 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
2293 int implied_not_equal(struct expression *expr, long long val)
2294 {
2295 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
2296 }
2297
2298 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
2299 {
2300 struct smatch_state *estate;
2301
2302 estate = get_state(SMATCH_EXTRA, name, sym);
2303 if (!estate)
2304 return 0;
2305 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
2306 return 1;
2307 return 0;
2308 }
2309
2310 bool is_noderef_ptr(struct expression *expr)
2311 {
2312 struct range_list *rl;
2313
2314 if (!get_implied_rl(expr, &rl))
2315 return false;
2316 return is_noderef_ptr_rl(rl);
2317 }
2318
2319 static int parent_is_err_or_null_var_sym_helper(const char *name, struct symbol *sym, bool check_err_ptr)
2320 {
2321 struct smatch_state *state;
2322 char buf[256];
2323 char *start;
2324 int len;
2325
2326 strncpy(buf, name, sizeof(buf) - 1);
2327 buf[sizeof(buf) - 1] = '\0';
2328
2329 start = &buf[0];
2330 while (*start == '*') {
2331 start++;
2332 state = __get_state(SMATCH_EXTRA, start, sym);
2333 if (!state)
2334 continue;
2335 if (!estate_rl(state))
2336 return 1;
2337 if (is_noderef_ptr_rl(estate_rl(state)))
2338 return 1;
2339 }
2340
2341 start = &buf[0];
2342 while (*start == '&')
2343 start++;
2344
2345 len = strlen(start);
2346 while (true) {
2347 while (len > 0) {
2348 len--;
2349 if (start[len] == '-' ||
2350 start[len] == '.') {
2351 start[len] = '\0';
2352 break;
2353 }
2354 }
2355 if (len == 0)
2356 return 0;
2357 state = __get_state(SMATCH_EXTRA, start, sym);
2358 if (!state)
2359 continue;
2360 if (is_noderef_ptr_rl(estate_rl(state)))
2361 return 1;
2362 }
2363 }
2364
2365 int parent_is_null_var_sym(const char *name, struct symbol *sym)
2366 {
2367 return parent_is_err_or_null_var_sym_helper(name, sym, false);
2368 }
2369
2370 int parent_is_err_or_null_var_sym(const char *name, struct symbol *sym)
2371 {
2372 return parent_is_err_or_null_var_sym_helper(name, sym, (option_project == PROJ_KERNEL));
2373 }
2374
2375 int parent_is_null(struct expression *expr)
2376 {
2377 struct symbol *sym;
2378 char *var;
2379 int ret = 0;
2380
2381 expr = strip_expr(expr);
2382 var = expr_to_var_sym(expr, &sym);
2383 if (!var || !sym)
2384 goto free;
2385 ret = parent_is_null_var_sym(var, sym);
2386 free:
2387 free_string(var);
2388 return ret;
2389 }
2390
2391 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
2392 {
2393 *(int *)found = 1;
2394 return 0;
2395 }
2396
2397 static int is_kzalloc_info(struct sm_state *sm)
2398 {
2399 sval_t sval;
2400
2401 /*
2402 * kzalloc() information is treated as special because so there is just
2403 * a lot of stuff initialized to zero and it makes building the database
2404 * take hours and hours.
2405 *
2406 * In theory, we should just remove this line and not pass any unused
2407 * information, but I'm not sure enough that this code works so I want
2408 * to hold off on that for now.
2409 */
2410 if (!estate_get_single_value(sm->state, &sval))
2411 return 0;
2412 if (sval.value != 0)
2413 return 0;
2414 return 1;
2415 }
2416
2417 static int is_really_long(struct sm_state *sm)
2418 {
2419 const char *p;
2420 int cnt = 0;
2421
2422 p = sm->name;
2423 while ((p = strstr(p, "->"))) {
2424 p += 2;
2425 cnt++;
2426 }
2427
2428 if (cnt < 3 ||
2429 strlen(sm->name) < 40)
2430 return 0;
2431 return 1;
2432 }
2433
2434 static int filter_unused_param_value_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2435 {
2436 int found = 0;
2437
2438 /* for function pointers assume everything is used */
2439 if (call->fn->type != EXPR_SYMBOL)
2440 return 0;
2441
2442 if (strcmp(printed_name, "$") == 0 ||
2443 strcmp(printed_name, "*$") == 0)
2444 return 0;
2445
2446 /*
2447 * This is to handle __builtin_mul_overflow(). In an ideal world we
2448 * would only need this for invalid code.
2449 *
2450 */
2451 if (!call->fn->symbol)
2452 return 0;
2453
2454 if (!is_kzalloc_info(sm) && !is_really_long(sm))
2455 return 0;
2456
2457 run_sql(&param_used_callback, &found,
2458 "select * from return_implies where %s and type = %d and parameter = %d and key = '%s';",
2459 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
2460 if (found)
2461 return 0;
2462
2463 /* If the database is not built yet, then assume everything is used */
2464 run_sql(&param_used_callback, &found,
2465 "select * from return_implies where %s and type = %d;",
2466 get_static_filter(call->fn->symbol), PARAM_USED);
2467 if (!found)
2468 return 0;
2469
2470 return 1;
2471 }
2472
2473 struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
2474 {
2475 struct smatch_state *state;
2476
2477 /*
2478 * Here is the difference between implied value and real absolute, say
2479 * you have:
2480 *
2481 * int a = (u8)x;
2482 *
2483 * Then you know that a is 0-255. That's real absolute. But you don't
2484 * know for sure that it actually goes up to 255. So it's not implied.
2485 * Implied indicates a degree of certainty.
2486 *
2487 * But then say you cap "a" at 8. That means you know it goes up to
2488 * 8. So now the implied value is s32min-8. But you can combine it
2489 * with the real absolute to say that actually it's 0-8.
2490 *
2491 * We are combining it here. But now that I think about it, this is
2492 * probably not the ideal place to combine it because it should proably
2493 * be done earlier. Oh well, this is an improvement on what was there
2494 * before so I'm going to commit this code.
2495 *
2496 */
2497
2498 state = get_real_absolute_state_var_sym(name, sym);
2499 if (!state || !estate_rl(state))
2500 return start;
2501
2502 return rl_intersection(estate_rl(state), start);
2503 }
2504
2505 struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
2506 {
2507 struct smatch_state *state;
2508 struct range_list *abs_rl;
2509
2510 state = get_real_absolute_state(expr);
2511 if (!state || !estate_rl(state))
2512 return start;
2513
2514 abs_rl = cast_rl(rl_type(start), estate_rl(state));
2515 return rl_intersection(abs_rl, start);
2516 }
2517
2518 static void caller_info_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2519 {
2520 struct range_list *rl;
2521 sval_t dummy;
2522
2523 if (estate_is_whole(sm->state) || !estate_rl(sm->state))
2524 return;
2525 if (filter_unused_param_value_info(call, param, printed_name, sm))
2526 return;
2527 rl = estate_rl(sm->state);
2528 rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
2529 if (!rl)
2530 return;
2531 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
2532 if (!estate_get_single_value(sm->state, &dummy)) {
2533 if (estate_has_hard_max(sm->state))
2534 sql_insert_caller_info(call, HARD_MAX, param, printed_name,
2535 sval_to_str(estate_max(sm->state)));
2536 if (estate_has_fuzzy_max(sm->state))
2537 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
2538 sval_to_str(estate_get_fuzzy_max(sm->state)));
2539 }
2540 }
2541
2542 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
2543 {
2544 struct symbol *returned_sym;
2545 char *returned_name;
2546 struct sm_state *sm;
2547 char *compare_str;
2548 char name_buf[256];
2549 char val_buf[256];
2550 int len;
2551
2552 // FIXME handle *$
2553
2554 if (!is_pointer(expr))
2555 return;
2556 if (return_ranges && strstr(return_ranges, "[==$"))
2557 return;
2558
2559 returned_name = expr_to_var_sym(expr, &returned_sym);
2560 if (!returned_name || !returned_sym)
2561 goto free;
2562 len = strlen(returned_name);
2563
2564 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
2565 if (!estate_rl(sm->state))
2566 continue;
2567 if (returned_sym != sm->sym)
2568 continue;
2569 if (strncmp(returned_name, sm->name, len) != 0)
2570 continue;
2571 if (sm->name[len] != '-')
2572 continue;
2573
2574 snprintf(name_buf, sizeof(name_buf), "$%s", sm->name + len);
2575
2576 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
2577 if (!compare_str && estate_is_whole(sm->state))
2578 continue;
2579 snprintf(val_buf, sizeof(val_buf), "%s%s", sm->state->name, compare_str ?: "");
2580
2581 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
2582 -1, name_buf, val_buf);
2583 } END_FOR_EACH_SM(sm);
2584
2585 free:
2586 free_string(returned_name);
2587 }
2588
2589 static void db_limited_before(void)
2590 {
2591 unmatched_stree = clone_stree(__get_cur_stree());
2592 }
2593
2594 static void db_limited_after(void)
2595 {
2596 free_stree(&unmatched_stree);
2597 }
2598
2599 static int basically_the_same(struct range_list *orig, struct range_list *new)
2600 {
2601 return rl_equiv(orig, new);
2602 }
2603
2604 static void db_param_limit_binops(struct expression *arg, char *key, struct range_list *rl)
2605 {
2606 struct range_list *left_rl;
2607 sval_t zero = { .type = rl_type(rl), };
2608 sval_t sval;
2609
2610 if (strcmp(key, "$") != 0)
2611 return;
2612 if (arg->op != '*')
2613 return;
2614 if (!get_implied_value(arg->right, &sval))
2615 return;
2616 if (can_integer_overflow(get_type(arg), arg))
2617 return;
2618
2619 left_rl = rl_binop(rl, '/', alloc_rl(sval, sval));
2620 if (!rl_has_sval(rl, zero))
2621 left_rl = remove_range(left_rl, zero, zero);
2622
2623 set_extra_expr_nomod(arg->left, alloc_estate_rl(left_rl));
2624 }
2625
2626 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
2627 {
2628 struct expression *arg;
2629 char *name;
2630 struct symbol *sym;
2631 struct var_sym_list *vsl = NULL;
2632 struct sm_state *sm;
2633 struct symbol *compare_type, *var_type;
2634 struct range_list *rl;
2635 struct range_list *limit;
2636 struct range_list *new;
2637 char *other_name;
2638 struct symbol *other_sym;
2639
2640 while (expr->type == EXPR_ASSIGNMENT)
2641 expr = strip_expr(expr->right);
2642 if (expr->type != EXPR_CALL)
2643 return;
2644
2645 arg = get_argument_from_call_expr(expr->args, param);
2646 if (!arg)
2647 return;
2648
2649 if (strcmp(key, "$") == 0)
2650 compare_type = get_arg_type(expr->fn, param);
2651 else
2652 compare_type = get_member_type_from_key(arg, key);
2653
2654 call_results_to_rl(expr, compare_type, value, &limit);
2655 if (strcmp(key, "$") == 0)
2656 move_known_to_rl(&arg, &limit);
2657 name = get_chunk_from_key(arg, key, &sym, &vsl);
2658 if (!name)
2659 return;
2660 if (op != PARAM_LIMIT && !sym)
2661 goto free;
2662
2663 sm = get_sm_state(SMATCH_EXTRA, name, sym);
2664 if (sm)
2665 rl = estate_rl(sm->state);
2666 else
2667 rl = alloc_whole_rl(compare_type);
2668
2669 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
2670 goto free;
2671
2672 new = rl_intersection(rl, limit);
2673
2674 var_type = get_member_type_from_key(arg, key);
2675 new = cast_rl(var_type, new);
2676
2677 /* We want to preserve the implications here */
2678 if (sm && basically_the_same(rl, new))
2679 goto free;
2680 other_name = get_other_name_sym(name, sym, &other_sym);
2681
2682 if (op == PARAM_LIMIT)
2683 set_extra_nomod_vsl(name, sym, vsl, NULL, alloc_estate_rl(new));
2684 else
2685 set_extra_mod(name, sym, NULL, alloc_estate_rl(new));
2686
2687 if (other_name && other_sym) {
2688 if (op == PARAM_LIMIT)
2689 set_extra_nomod_vsl(other_name, other_sym, vsl, NULL, alloc_estate_rl(new));
2690 else
2691 set_extra_mod(other_name, other_sym, NULL, alloc_estate_rl(new));
2692 }
2693
2694 if (op == PARAM_LIMIT && arg->type == EXPR_BINOP)
2695 db_param_limit_binops(arg, key, new);
2696 free:
2697 free_string(name);
2698 }
2699
2700 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
2701 {
2702 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
2703 }
2704
2705 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
2706 {
2707 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
2708 }
2709
2710 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
2711 {
2712 struct expression *arg, *gen_expr;
2713 char *name;
2714 char *other_name = NULL;
2715 struct symbol *sym, *other_sym;
2716 struct symbol *param_type, *arg_type;
2717 struct smatch_state *state;
2718 struct range_list *new = NULL;
2719 struct range_list *added = NULL;
2720
2721 while (expr->type == EXPR_ASSIGNMENT)
2722 expr = strip_expr(expr->right);
2723 if (expr->type != EXPR_CALL)
2724 return;
2725
2726 arg = get_argument_from_call_expr(expr->args, param);
2727 if (!arg)
2728 return;
2729
2730 arg_type = get_arg_type_from_key(expr->fn, param, arg, key);
2731 param_type = get_member_type_from_key(arg, key);
2732 if (param_type && param_type->type == SYM_STRUCT)
2733 return;
2734 name = get_variable_from_key(arg, key, &sym);
2735 if (!name || !sym)
2736 goto free;
2737 gen_expr = gen_expression_from_key(arg, key);
2738
2739 state = get_state(SMATCH_EXTRA, name, sym);
2740 if (state)
2741 new = estate_rl(state);
2742
2743 call_results_to_rl(expr, arg_type, value, &added);
2744 added = cast_rl(param_type, added);
2745 if (op == PARAM_SET)
2746 new = added;
2747 else
2748 new = rl_union(new, added);
2749
2750 other_name = get_other_name_sym_nostack(name, sym, &other_sym);
2751 set_extra_mod(name, sym, gen_expr, alloc_estate_rl(new));
2752 if (other_name && other_sym)
2753 set_extra_mod(other_name, other_sym, gen_expr, alloc_estate_rl(new));
2754 free:
2755 free_string(other_name);
2756 free_string(name);
2757 }
2758
2759 static void db_param_add(struct expression *expr, int param, char *key, char *value)
2760 {
2761 in_param_set = true;
2762 db_param_add_set(expr, param, key, value, PARAM_ADD);
2763 in_param_set = false;
2764 }
2765
2766 static void db_param_set(struct expression *expr, int param, char *key, char *value)
2767 {
2768 in_param_set = true;
2769 db_param_add_set(expr, param, key, value, PARAM_SET);
2770 in_param_set = false;
2771 }
2772
2773 static void match_lost_param(struct expression *call, int param)
2774 {
2775 struct expression *arg;
2776
2777 if (is_const_param(call->fn, param))
2778 return;
2779
2780 arg = get_argument_from_call_expr(call->args, param);
2781 if (!arg)
2782 return;
2783
2784 arg = strip_expr(arg);
2785 if (arg->type == EXPR_PREOP && arg->op == '&')
2786 set_extra_expr_mod(arg->unop, alloc_estate_whole(get_type(arg->unop)));
2787 else
2788 ; /* if pointer then set struct members, maybe?*/
2789 }
2790
2791 static void db_param_value(struct expression *expr, int param, char *key, char *value)
2792 {
2793 struct expression *call;
2794 char *name;
2795 struct symbol *sym;
2796 struct symbol *type;
2797 struct range_list *rl = NULL;
2798
2799 if (param != -1)
2800 return;
2801
2802 call = expr;
2803 while (call->type == EXPR_ASSIGNMENT)
2804 call = strip_expr(call->right);
2805 if (call->type != EXPR_CALL)
2806 return;
2807
2808 type = get_member_type_from_key(expr->left, key);
2809 name = get_variable_from_key(expr->left, key, &sym);
2810 if (!name || !sym)
2811 goto free;
2812
2813 call_results_to_rl(call, type, value, &rl);
2814
2815 set_extra_mod(name, sym, NULL, alloc_estate_rl(rl));
2816 free:
2817 free_string(name);
2818 }
2819
2820 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2821 {
2822 struct expression *expr;
2823 struct range_list *rl = NULL;
2824 struct smatch_state *state;
2825 struct symbol *type;
2826 char *key_orig = key;
2827 char *fullname;
2828 sval_t dummy;
2829
2830 expr = symbol_expression(sym);
2831 fullname = get_variable_from_key(expr, key, NULL);
2832 if (!fullname)
2833 return;
2834
2835 type = get_member_type_from_key(expr, key_orig);
2836 str_to_rl(type, value, &rl);
2837 state = alloc_estate_rl(rl);
2838 if (estate_get_single_value(state, &dummy))
2839 estate_set_hard_max(state);
2840 set_state(SMATCH_EXTRA, fullname, sym, state);
2841 }
2842
2843 static void set_param_fuzzy_max(const char *name, struct symbol *sym, char *key, char *value)
2844 {
2845 struct expression *expr;
2846 struct range_list *rl = NULL;
2847 struct smatch_state *state;
2848 struct symbol *type;
2849 char *fullname;
2850 sval_t max;
2851
2852 expr = symbol_expression(sym);
2853 fullname = get_variable_from_key(expr, key, NULL);
2854 if (!fullname)
2855 return;
2856
2857 state = get_state(SMATCH_EXTRA, fullname, sym);
2858 if (!state)
2859 return;
2860 type = estate_type(state);
2861 str_to_rl(type, value, &rl);
2862 if (!rl_to_sval(rl, &max))
2863 return;
2864 estate_set_fuzzy_max(state, max);
2865 }
2866
2867 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2868 {
2869 struct smatch_state *state;
2870 struct expression *expr;
2871 char *fullname;
2872
2873 expr = symbol_expression(sym);
2874 fullname = get_variable_from_key(expr, key, NULL);
2875 if (!fullname)
2876 return;
2877
2878 state = get_state(SMATCH_EXTRA, fullname, sym);
2879 if (!state)
2880 return;
2881 estate_set_hard_max(state);
2882 }
2883
2884 static struct sm_state *get_sm_from_call(struct expression *expr)
2885 {
2886 char buf[32];
2887
2888 if (is_fake_call(expr))
2889 return NULL;
2890
2891 snprintf(buf, sizeof(buf), "return %p", expr);
2892 return get_sm_state(SMATCH_EXTRA, buf, NULL);
2893 }
2894
2895 struct sm_state *get_extra_sm_state(struct expression *expr)
2896 {
2897 char *name;
2898 struct symbol *sym;
2899 struct sm_state *ret = NULL;
2900
2901 expr = strip_expr(expr);
2902 if (!expr)
2903 return NULL;
2904
2905 if (expr->type == EXPR_CALL)
2906 return get_sm_from_call(expr);
2907
2908 name = expr_to_known_chunk_sym(expr, &sym);
2909 if (!name)
2910 goto free;
2911
2912 ret = get_sm_state(SMATCH_EXTRA, name, sym);
2913 free:
2914 free_string(name);
2915 return ret;
2916 }
2917
2918 struct smatch_state *get_extra_state(struct expression *expr)
2919 {
2920 struct sm_state *sm;
2921
2922 sm = get_extra_sm_state(expr);
2923 if (!sm)
2924 return NULL;
2925 return sm->state;
2926 }
2927
2928 void register_smatch_extra(int id)
2929 {
2930 my_id = id;
2931
2932 set_dynamic_states(my_id);
2933 add_merge_hook(my_id, &merge_estates);
2934 add_unmatched_state_hook(my_id, &unmatched_state);
2935 select_caller_info_hook(set_param_value, PARAM_VALUE);
2936 select_caller_info_hook(set_param_fuzzy_max, FUZZY_MAX);
2937 select_caller_info_hook(set_param_hard_max, HARD_MAX);
2938 select_return_states_before(&db_limited_before);
2939 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
2940 select_return_states_hook(PARAM_FILTER, &db_param_filter);
2941 select_return_states_hook(PARAM_ADD, &db_param_add);
2942 select_return_states_hook(PARAM_SET, &db_param_set);
2943 add_lost_param_hook(&match_lost_param);
2944 select_return_states_hook(PARAM_VALUE, &db_param_value);
2945 select_return_states_after(&db_limited_after);
2946 }
2947
2948 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
2949 {
2950 struct var_sym_list *links;
2951 struct var_sym *tmp;
2952 struct smatch_state *state;
2953
2954 links = sm->state->data;
2955
2956 FOR_EACH_PTR(links, tmp) {
2957 if (sm->sym == tmp->sym &&
2958 strcmp(sm->name, tmp->var) == 0)
2959 continue;
2960 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
2961 if (!state)
2962 continue;
2963 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
2964 } END_FOR_EACH_PTR(tmp);
2965 set_state(link_id, sm->name, sm->sym, &undefined);
2966 }
2967
2968 void register_smatch_extra_links(int id)
2969 {
2970 link_id = id;
2971 set_dynamic_states(link_id);
2972 }
2973
2974 void register_smatch_extra_late(int id)
2975 {
2976 add_merge_hook(link_id, &merge_link_states);
2977 add_modification_hook(link_id, &match_link_modify);
2978 add_hook(&match_dereferences, DEREF_HOOK);
2979 add_hook(&match_pointer_as_array, OP_HOOK);
2980 select_return_implies_hook(DEREFERENCE, &set_param_dereferenced);
2981 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
2982 add_hook(&match_assign, ASSIGNMENT_HOOK);
2983 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
2984 add_hook(&unop_expr, OP_HOOK);
2985 add_hook(&asm_expr, ASM_HOOK);
2986
2987 add_caller_info_callback(my_id, caller_info_callback);
2988 add_split_return_callback(&returned_struct_members);
2989
2990 // add_hook(&assume_indexes_are_valid, OP_HOOK);
2991 }
Static analysis for C