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kernel.no_return_funcs: add kunit_do_failed_assertion()
[smatch/bkmgit.git] / smatch_extra.c
blobcf0e2e7d4604cb533715c6acb32b23d5c969dadc
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(mod_hook_list, mod_hook *);
65 static struct mod_hook_list *extra_mod_hooks;
66 static struct mod_hook_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 mod_hook_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 extern int __no_limits;
172 static void mark_sub_members_gone(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
173 {
174 struct sm_state *sm;
175
176 if (__in_fake_assign)
177 return;
178 if (is_fake_var_assign(expr))
179 return;
180
181 if (!estate_type(state) || estate_type(state)->type != SYM_PTR)
182 return;
183 if (!is_noderef_ptr_rl(estate_rl(state)))
184 return;
185
186 FOR_EACH_MY_SM(SMATCH_EXTRA, __get_cur_stree(), sm) {
187 if (sm->sym != sym)
188 continue;
189 if (strcmp(name, sm->name) == 0)
190 continue;
191 if (!is_sub_member(name, sym, sm))
192 continue;
193 __no_limits++;
194 set_extra_nomod(sm->name, sm->sym, NULL, alloc_estate_empty());
195 __no_limits--;
196 } END_FOR_EACH_SM(sm);
197 }
198
199 static bool is_fake_assign(struct expression *expr)
200 {
201 struct expression *faked;
202
203 if (is_fake_var_assign(expr))
204 return true;
205
206 faked = get_faked_expression();
207 if (!faked || faked->type != EXPR_ASSIGNMENT || faked->op != '=')
208 return false;
209
210 faked = strip_expr(faked->right);
211 if (faked->type == EXPR_PREOP && faked->op == '&')
212 return true;
213
214 return false;
215 }
216
217 static void call_update_mtag_data(struct expression *expr,
218 struct smatch_state *state)
219 {
220 if (is_fake_assign(expr))
221 return;
222
223 update_mtag_data(expr, state);
224 }
225
226 static bool in_param_set;
227 void set_extra_mod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
228 {
229 if (!expr)
230 expr = gen_expression_from_name_sym(name, sym);
231 remove_from_equiv(name, sym);
232 set_union_info(name, sym, expr, state);
233 mark_sub_members_gone(name, sym, expr, state);
234 call_extra_mod_hooks(name, sym, expr, state);
235 call_update_mtag_data(expr, state);
236 if ((__in_fake_assign || in_param_set) &&
237 estate_is_unknown(state) && !get_state(SMATCH_EXTRA, name, sym))
238 return;
239 set_state(SMATCH_EXTRA, name, sym, state);
240 }
241
242 static void set_extra_nomod_helper(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
243 {
244 call_extra_nomod_hooks(name, sym, expr, state);
245 set_state(SMATCH_EXTRA, name, sym, state);
246 }
247
248 static char *get_pointed_at(const char *name, struct symbol *sym, struct symbol **new_sym)
249 {
250 struct expression *assigned;
251
252 /*
253 * Imagine we have an assignment: "foo = &addr;" then the other name
254 * of "*foo" is addr.
255 */
256
257 if (name[0] != '*')
258 return NULL;
259 if (strcmp(name + 1, sym->ident->name) != 0)
260 return NULL;
261
262 assigned = get_assigned_expr_name_sym(sym->ident->name, sym);
263 if (!assigned)
264 return NULL;
265 assigned = strip_parens(assigned);
266 if (assigned->type != EXPR_PREOP || assigned->op != '&')
267 return NULL;
268
269 return expr_to_var_sym(assigned->unop, new_sym);
270 }
271
272 char *get_other_name_sym_from_chunk(const char *name, const char *chunk, int len, struct symbol *sym, struct symbol **new_sym)
273 {
274 struct expression *assigned;
275 char *orig_name = NULL;
276 char buf[256];
277 char *ret;
278
279 assigned = get_assigned_expr_name_sym(chunk, sym);
280 if (!assigned)
281 return NULL;
282 if (assigned->type == EXPR_CALL)
283 return map_call_to_other_name_sym(name, sym, new_sym);
284 if (assigned->type == EXPR_PREOP && assigned->op == '&') {
285
286 orig_name = expr_to_var_sym(assigned, new_sym);
287 if (!orig_name || !*new_sym)
288 goto free;
289
290 snprintf(buf, sizeof(buf), "%s.%s", orig_name + 1, name + len);
291 ret = alloc_string(buf);
292 free_string(orig_name);
293 return ret;
294 }
295
296 orig_name = expr_to_var_sym(assigned, new_sym);
297 if (!orig_name || !*new_sym)
298 goto free;
299
300 snprintf(buf, sizeof(buf), "%s->%s", orig_name, name + len);
301 ret = alloc_string(buf);
302 free_string(orig_name);
303 return ret;
304 free:
305 free_string(orig_name);
306 return NULL;
307 }
308
309 static char *get_long_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
310 {
311 struct expression *orig;
312 struct symbol *orig_sym;
313 char *orig_name, *ret;
314
315 if (!sym || !sym->ident)
316 return NULL;
317
318 orig = get_assigned_expr_name_sym(sym->ident->name, sym);
319 if (orig) {
320 orig_name = expr_to_var_sym(orig, &orig_sym);
321 if (!orig_name)
322 return NULL;
323
324 ret = swap_names(name, sym->ident->name, orig_name);
325 free_string(orig_name);
326 if (ret)
327 *new_sym = orig_sym;
328 return ret;
329 }
330
331 return NULL;
332 }
333
334 char *get_other_name_sym_helper(const char *name, struct symbol *sym, struct symbol **new_sym, bool use_stack)
335 {
336 char buf[256];
337 char *ret;
338 int len;
339
340 *new_sym = NULL;
341
342 if (!sym || !sym->ident)
343 return NULL;
344
345 ret = get_pointed_at(name, sym, new_sym);
346 if (ret)
347 return ret;
348
349 ret = map_long_to_short_name_sym(name, sym, new_sym, use_stack);
350 if (ret)
351 return ret;
352
353 len = snprintf(buf, sizeof(buf), "%s", name);
354 if (len >= sizeof(buf) - 2)
355 return NULL;
356
357 while (use_stack && len >= 1) {
358 if (buf[len] == '>' && buf[len - 1] == '-') {
359 len--;
360 buf[len] = '\0';
361 ret = get_other_name_sym_from_chunk(name, buf, len + 2, sym, new_sym);
362 if (ret)
363 return ret;
364 }
365 len--;
366 }
367
368 ret = get_long_name_sym(name, sym, new_sym, use_stack);
369 if (ret)
370 return ret;
371
372 return NULL;
373 }
374
375 char *get_other_name_sym(const char *name, struct symbol *sym, struct symbol **new_sym)
376 {
377 return get_other_name_sym_helper(name, sym, new_sym, true);
378 }
379
380 char *get_other_name_sym_nostack(const char *name, struct symbol *sym, struct symbol **new_sym)
381 {
382 return get_other_name_sym_helper(name, sym, new_sym, false);
383 }
384
385 void set_extra_mod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
386 {
387 char *new_name;
388 struct symbol *new_sym;
389
390 set_extra_mod_helper(name, sym, expr, state);
391 new_name = get_other_name_sym_nostack(name, sym, &new_sym);
392 if (new_name && new_sym)
393 set_extra_mod_helper(new_name, new_sym, NULL, state);
394 free_string(new_name);
395 }
396
397 static struct expression *chunk_get_array_base(struct expression *expr)
398 {
399 /*
400 * The problem with is_array() is that it only returns true for things
401 * like foo[1] but not for foo[1].bar.
402 *
403 */
404 expr = strip_expr(expr);
405 while (expr && expr->type == EXPR_DEREF)
406 expr = strip_expr(expr->deref);
407 return get_array_base(expr);
408 }
409
410 static int chunk_has_array(struct expression *expr)
411 {
412 return !!chunk_get_array_base(expr);
413 }
414
415 static void clear_array_states(struct expression *array)
416 {
417 struct sm_state *sm;
418
419 sm = get_sm_state_expr(link_id, array);
420 if (sm)
421 match_link_modify(sm, NULL);
422 }
423
424 static void set_extra_array_mod(struct expression *expr, struct smatch_state *state)
425 {
426 struct expression *array;
427 struct var_sym_list *vsl;
428 struct var_sym *vs;
429 char *name;
430 struct symbol *sym;
431
432 array = chunk_get_array_base(expr);
433
434 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
435 if (!name || !vsl) {
436 clear_array_states(array);
437 goto free;
438 }
439
440 FOR_EACH_PTR(vsl, vs) {
441 store_link(link_id, vs->var, vs->sym, name, sym);
442 } END_FOR_EACH_PTR(vs);
443
444 call_extra_mod_hooks(name, sym, expr, state);
445 set_state(SMATCH_EXTRA, name, sym, state);
446 free:
447 free_string(name);
448 }
449
450 void set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
451 {
452 struct symbol *sym;
453 char *name;
454
455 if (chunk_has_array(expr)) {
456 set_extra_array_mod(expr, state);
457 return;
458 }
459
460 expr = strip_expr(expr);
461 name = expr_to_var_sym(expr, &sym);
462 if (!name || !sym)
463 goto free;
464 set_extra_mod(name, sym, expr, state);
465 free:
466 free_string(name);
467 }
468
469 void set_extra_nomod(const char *name, struct symbol *sym, struct expression *expr, struct smatch_state *state)
470 {
471 char *new_name;
472 struct symbol *new_sym;
473 struct relation *rel;
474 struct smatch_state *orig_state;
475
476 orig_state = get_state(SMATCH_EXTRA, name, sym);
477
478 /* don't save unknown states if leaving it blank is the same */
479 if (!orig_state && estate_is_unknown(state))
480 return;
481
482 new_name = get_other_name_sym(name, sym, &new_sym);
483 if (new_name && new_sym)
484 set_extra_nomod_helper(new_name, new_sym, expr, state);
485 free_string(new_name);
486
487 if (!estate_related(orig_state)) {
488 set_extra_nomod_helper(name, sym, expr, state);
489 return;
490 }
491
492 set_related(state, estate_related(orig_state));
493 FOR_EACH_PTR(estate_related(orig_state), rel) {
494 struct smatch_state *estate;
495
496 estate = get_state(SMATCH_EXTRA, rel->name, rel->sym);
497 if (!estate)
498 continue;
499 set_extra_nomod_helper(rel->name, rel->sym, expr, clone_estate_cast(estate_type(estate), state));
500 } END_FOR_EACH_PTR(rel);
501 }
502
503 void set_extra_nomod_vsl(const char *name, struct symbol *sym, struct var_sym_list *vsl, struct expression *expr, struct smatch_state *state)
504 {
505 struct var_sym *vs;
506
507 FOR_EACH_PTR(vsl, vs) {
508 store_link(link_id, vs->var, vs->sym, name, sym);
509 } END_FOR_EACH_PTR(vs);
510
511 set_extra_nomod(name, sym, expr, state);
512 }
513
514 /*
515 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
516 */
517 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
518 {
519 struct var_sym_list *vsl;
520 struct var_sym *vs;
521 char *name;
522 struct symbol *sym;
523
524 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
525 if (!name || !vsl)
526 goto free;
527 FOR_EACH_PTR(vsl, vs) {
528 store_link(link_id, vs->var, vs->sym, name, sym);
529 } END_FOR_EACH_PTR(vs);
530
531 set_extra_nomod(name, sym, expr, state);
532 free:
533 free_string(name);
534 }
535
536 static void set_extra_true_false(const char *name, struct symbol *sym,
537 struct smatch_state *true_state,
538 struct smatch_state *false_state)
539 {
540 char *new_name;
541 struct symbol *new_sym;
542 struct relation *rel;
543 struct smatch_state *orig_state;
544
545 if (!true_state && !false_state)
546 return;
547
548 if (in_warn_on_macro())
549 return;
550
551 new_name = get_other_name_sym(name, sym, &new_sym);
552 if (new_name && new_sym)
553 set_true_false_states(SMATCH_EXTRA, new_name, new_sym, true_state, false_state);
554 free_string(new_name);
555
556 orig_state = get_state(SMATCH_EXTRA, name, sym);
557
558 if (!estate_related(orig_state)) {
559 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
560 return;
561 }
562
563 if (true_state)
564 set_related(true_state, estate_related(orig_state));
565 if (false_state)
566 set_related(false_state, estate_related(orig_state));
567
568 FOR_EACH_PTR(estate_related(orig_state), rel) {
569 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
570 true_state, false_state);
571 } END_FOR_EACH_PTR(rel);
572 }
573
574 static void set_extra_chunk_true_false(struct expression *expr,
575 struct smatch_state *true_state,
576 struct smatch_state *false_state)
577 {
578 struct var_sym_list *vsl;
579 struct var_sym *vs;
580 struct symbol *type;
581 char *name;
582 struct symbol *sym;
583
584 if (in_warn_on_macro())
585 return;
586
587 type = get_type(expr);
588 if (!type)
589 return;
590
591 name = expr_to_chunk_sym_vsl(expr, &sym, &vsl);
592 if (!name || !vsl)
593 goto free;
594 FOR_EACH_PTR(vsl, vs) {
595 store_link(link_id, vs->var, vs->sym, name, sym);
596 } END_FOR_EACH_PTR(vs);
597
598 set_true_false_states(SMATCH_EXTRA, name, sym,
599 clone_estate(true_state),
600 clone_estate(false_state));
601 free:
602 free_string(name);
603 }
604
605 static void set_extra_expr_true_false(struct expression *expr,
606 struct smatch_state *true_state,
607 struct smatch_state *false_state)
608 {
609 char *name;
610 struct symbol *sym;
611 sval_t sval;
612
613 if (!true_state && !false_state)
614 return;
615
616 if (get_value(expr, &sval))
617 return;
618
619 expr = strip_expr(expr);
620 name = expr_to_var_sym(expr, &sym);
621 if (!name || !sym) {
622 free_string(name);
623 set_extra_chunk_true_false(expr, true_state, false_state);
624 return;
625 }
626 set_extra_true_false(name, sym, true_state, false_state);
627 free_string(name);
628 }
629
630 static int get_countdown_info(struct expression *condition, struct expression **unop, int *op, sval_t *right)
631 {
632 struct expression *unop_expr;
633 int comparison;
634 sval_t limit;
635
636 right->type = &int_ctype;
637 right->value = 0;
638
639 condition = strip_expr(condition);
640
641 if (condition->type == EXPR_COMPARE) {
642 comparison = remove_unsigned_from_comparison(condition->op);
643
644 if (comparison != SPECIAL_GTE && comparison != '>')
645 return 0;
646 if (!get_value(condition->right, &limit))
647 return 0;
648
649 unop_expr = condition->left;
650 if (unop_expr->type != EXPR_PREOP && unop_expr->type != EXPR_POSTOP)
651 return 0;
652 if (unop_expr->op != SPECIAL_DECREMENT)
653 return 0;
654
655 *unop = unop_expr;
656 *op = comparison;
657 *right = limit;
658
659 return 1;
660 }
661
662 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
663 return 0;
664 if (condition->op != SPECIAL_DECREMENT)
665 return 0;
666
667 *unop = condition;
668 *op = '>';
669
670 return 1;
671 }
672
673 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
674 {
675 struct expression *iter_var;
676 struct expression *condition, *unop;
677 struct symbol *type;
678 struct sm_state *sm;
679 struct smatch_state *estate;
680 int op;
681 sval_t start, right;
682
683 right.type = &int_ctype;
684 right.value = 0;
685
686 condition = strip_expr(loop->iterator_pre_condition);
687 if (!condition)
688 return NULL;
689
690 if (!get_countdown_info(condition, &unop, &op, &right))
691 return NULL;
692
693 iter_var = unop->unop;
694
695 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
696 if (!sm)
697 return NULL;
698 if (sval_cmp(estate_min(sm->state), right) < 0)
699 return NULL;
700 start = estate_max(sm->state);
701
702 type = get_type(iter_var);
703 right = sval_cast(type, right);
704 start = sval_cast(type, start);
705
706 if (sval_cmp(start, right) <= 0)
707 return NULL;
708 if (!sval_is_max(start))
709 start.value--;
710
711 if (op == SPECIAL_GTE)
712 right.value--;
713
714 if (unop->type == EXPR_PREOP) {
715 right.value++;
716 estate = alloc_estate_range(right, start);
717 if (estate_has_hard_max(sm->state))
718 estate_set_hard_max(estate);
719 estate_copy_fuzzy_max(estate, sm->state);
720 set_extra_expr_mod(iter_var, estate);
721 }
722 if (unop->type == EXPR_POSTOP) {
723 estate = alloc_estate_range(right, start);
724 if (estate_has_hard_max(sm->state))
725 estate_set_hard_max(estate);
726 estate_copy_fuzzy_max(estate, sm->state);
727 set_extra_expr_mod(iter_var, estate);
728 }
729 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
730 }
731
732 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
733 struct expression *condition)
734 {
735 struct expression *iter_var;
736 struct sm_state *sm;
737 struct smatch_state *estate;
738 sval_t start, end, max;
739 bool unknown_end = false;
740
741 iter_var = iter_expr->unop;
742 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
743 if (!sm)
744 return NULL;
745 if (!estate_get_single_value(sm->state, &start))
746 return NULL;
747 if (!get_implied_max(condition->right, &end)) {
748 end = sval_type_max(get_type(condition->right));
749 end = sval_cast(start.type, end);
750 if (sval_is_max(end))
751 unknown_end = true;
752 }
753
754 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
755 return NULL;
756
757 switch (condition->op) {
758 case SPECIAL_UNSIGNED_LT:
759 case SPECIAL_NOTEQUAL:
760 case '<':
761 if (!sval_is_min(end) && !unknown_end)
762 end.value--;
763 break;
764 case SPECIAL_UNSIGNED_LTE:
765 case SPECIAL_LTE:
766 break;
767 default:
768 return NULL;
769 }
770 if (sval_cmp(end, start) < 0)
771 return NULL;
772 end = sval_cast(start.type, end);
773 estate = alloc_estate_range(start, end);
774 if (get_hard_max(condition->right, &max)) {
775 if (!get_macro_name(condition->pos))
776 estate_set_hard_max(estate);
777 if (condition->op == '<' ||
778 condition->op == SPECIAL_UNSIGNED_LT ||
779 condition->op == SPECIAL_NOTEQUAL)
780 max.value--;
781 max = sval_cast(start.type, max);
782 estate_set_fuzzy_max(estate, max);
783 }
784 set_extra_expr_mod(iter_var, estate);
785 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
786 }
787
788 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
789 struct expression *condition)
790 {
791 struct expression *iter_var;
792 struct sm_state *sm;
793 struct smatch_state *estate;
794 sval_t start, end;
795
796 iter_var = iter_expr->unop;
797 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
798 if (!sm)
799 return NULL;
800 if (!estate_get_single_value(sm->state, &start))
801 return NULL;
802 if (!get_implied_min(condition->right, &end))
803 end = sval_type_min(get_type(iter_var));
804 end = sval_cast(estate_type(sm->state), end);
805 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
806 return NULL;
807
808 switch (condition->op) {
809 case SPECIAL_NOTEQUAL:
810 case '>':
811 if (!sval_is_max(end))
812 end.value++;
813 break;
814 case SPECIAL_GTE:
815 break;
816 default:
817 return NULL;
818 }
819 if (sval_cmp(end, start) > 0)
820 return NULL;
821 estate = alloc_estate_range(end, start);
822 estate_set_hard_max(estate);
823 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
824 set_extra_expr_mod(iter_var, estate);
825 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
826 }
827
828 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
829 {
830 struct expression *iter_expr;
831 struct expression *condition;
832
833 if (!loop->iterator_post_statement)
834 return NULL;
835 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
836 return NULL;
837 iter_expr = loop->iterator_post_statement->expression;
838 if (!loop->iterator_pre_condition)
839 return NULL;
840 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
841 return NULL;
842 condition = loop->iterator_pre_condition;
843
844 if (iter_expr->op == SPECIAL_INCREMENT)
845 return handle_canonical_for_inc(iter_expr, condition);
846 if (iter_expr->op == SPECIAL_DECREMENT)
847 return handle_canonical_for_dec(iter_expr, condition);
848 return NULL;
849 }
850
851 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
852 {
853 struct sm_state *ret;
854
855 /*
856 * Canonical loops are a hack. The proper way to handle this is to
857 * use two passes, but unfortunately, doing two passes makes parsing
858 * code twice as slow.
859 *
860 * What we do is we set the inside state here, which overwrites whatever
861 * __extra_match_condition() does. Then we set the outside state in
862 * __extra_pre_loop_hook_after().
863 *
864 */
865 __push_fake_cur_stree();
866 if (!loop->iterator_post_statement)
867 ret = handle_canonical_while_count_down(loop);
868 else
869 ret = handle_canonical_for_loops(loop);
870 *stree = __pop_fake_cur_stree();
871 return ret;
872 }
873
874 int __iterator_unchanged(struct sm_state *sm)
875 {
876 if (!sm)
877 return 0;
878 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
879 return 1;
880 return 0;
881 }
882
883 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
884 {
885 struct expression *unop;
886 int op;
887 sval_t limit, after_value;
888
889 if (!get_countdown_info(condition, &unop, &op, &limit))
890 return;
891 after_value = estate_min(sm->state);
892 after_value.value--;
893 set_extra_mod(sm->name, sm->sym, condition->unop, alloc_estate_sval(after_value));
894 }
895
896 void __extra_pre_loop_hook_after(struct sm_state *sm,
897 struct statement *iterator,
898 struct expression *condition)
899 {
900 struct expression *iter_expr;
901 sval_t limit;
902 struct smatch_state *state;
903 sval_t end;
904
905 if (!iterator) {
906 while_count_down_after(sm, condition);
907 return;
908 }
909
910 iter_expr = iterator->expression;
911
912 if (condition->type != EXPR_COMPARE)
913 return;
914
915 if (iter_expr->op == SPECIAL_INCREMENT) {
916 if (!get_implied_value(condition->right, &end) &&
917 sval_is_max(estate_max(sm->state)))
918 limit = estate_max(sm->state);
919 else
920 limit = sval_binop(estate_max(sm->state), '+',
921 sval_type_val(estate_type(sm->state), 1));
922 } else {
923 limit = sval_binop(estate_min(sm->state), '-',
924 sval_type_val(estate_type(sm->state), 1));
925 }
926 limit = sval_cast(estate_type(sm->state), limit);
927 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
928 if (iter_expr->op == SPECIAL_INCREMENT)
929 state = alloc_estate_range(estate_min(sm->state), limit);
930 else
931 state = alloc_estate_range(limit, estate_max(sm->state));
932 } else {
933 state = alloc_estate_sval(limit);
934 }
935 if (!estate_has_hard_max(sm->state)) {
936 estate_clear_hard_max(state);
937 }
938 if (estate_has_fuzzy_max(sm->state)) {
939 sval_t hmax = estate_get_fuzzy_max(sm->state);
940 sval_t max = estate_max(sm->state);
941
942 if (sval_cmp(hmax, max) != 0)
943 estate_clear_fuzzy_max(state);
944 } else if (!estate_has_fuzzy_max(sm->state)) {
945 estate_clear_fuzzy_max(state);
946 }
947
948 set_extra_mod(sm->name, sm->sym, iter_expr, state);
949 }
950
951 static bool get_global_rl(const char *name, struct symbol *sym, struct range_list **rl)
952 {
953 struct expression *expr;
954
955 if (!sym || !(sym->ctype.modifiers & MOD_TOPLEVEL) || !sym->ident)
956 return false;
957 if (strcmp(sym->ident->name, name) != 0)
958 return false;
959
960 expr = symbol_expression(sym);
961 return get_implied_rl(expr, rl);
962 }
963
964 static struct stree *unmatched_stree;
965 static struct smatch_state *unmatched_state(struct sm_state *sm)
966 {
967 struct smatch_state *state;
968 struct expression *expr;
969 struct range_list *rl;
970
971 if (unmatched_stree) {
972 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
973 if (state)
974 return state;
975 }
976 if (parent_is_gone_var_sym(sm->name, sm->sym))
977 return alloc_estate_empty();
978 if (get_global_rl(sm->name, sm->sym, &rl))
979 return alloc_estate_rl(rl);
980
981 expr = gen_expression_from_name_sym(sm->name, sm->sym);
982 if (!expr)
983 return alloc_estate_whole(estate_type(sm->state));
984 get_absolute_rl(expr, &rl);
985 return alloc_estate_rl(rl);
986 }
987
988 static void clear_the_pointed_at(struct expression *expr)
989 {
990 struct stree *stree;
991 char *name;
992 struct symbol *sym;
993 struct sm_state *tmp;
994
995 name = expr_to_var_sym(expr, &sym);
996 if (!name || !sym)
997 goto free;
998
999 stree = __get_cur_stree();
1000 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
1001 if (tmp->name[0] != '*')
1002 continue;
1003 if (tmp->sym != sym)
1004 continue;
1005 if (strcmp(tmp->name + 1, name) != 0)
1006 continue;
1007 set_extra_mod(tmp->name, tmp->sym, expr, alloc_estate_whole(estate_type(tmp->state)));
1008 } END_FOR_EACH_SM(tmp);
1009
1010 free:
1011 free_string(name);
1012 }
1013
1014 static int is_const_param(struct expression *expr, int param)
1015 {
1016 struct symbol *type;
1017
1018 type = get_arg_type(expr, param);
1019 if (!type)
1020 return 0;
1021 if (type->ctype.modifiers & MOD_CONST)
1022 return 1;
1023 return 0;
1024 }
1025
1026 static void match_function_call(struct expression *expr)
1027 {
1028 struct expression *arg;
1029 struct expression *tmp;
1030 int param = -1;
1031
1032 /* if we have the db this is handled in smatch_function_hooks.c */
1033 if (!option_no_db)
1034 return;
1035 if (inlinable(expr->fn))
1036 return;
1037
1038 FOR_EACH_PTR(expr->args, arg) {
1039 param++;
1040 if (is_const_param(expr->fn, param))
1041 continue;
1042 tmp = strip_expr(arg);
1043 if (tmp->type == EXPR_PREOP && tmp->op == '&')
1044 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
1045 else
1046 clear_the_pointed_at(tmp);
1047 } END_FOR_EACH_PTR(arg);
1048 }
1049
1050 int values_fit_type(struct expression *left, struct expression *right)
1051 {
1052 struct range_list *rl;
1053 struct symbol *type;
1054
1055 type = get_type(left);
1056 if (!type)
1057 return 0;
1058 get_absolute_rl(right, &rl);
1059 if (type == rl_type(rl))
1060 return 1;
1061 if (sval_is_negative(rl_min(rl))) {
1062 if (type_unsigned(type))
1063 return 0;
1064 if (sval_cmp(sval_type_min(type), rl_min(rl)) > 0)
1065 return 0;
1066 }
1067 if (sval_cmp(sval_type_max(type), rl_max(rl)) < 0)
1068 return 0;
1069 return 1;
1070 }
1071
1072 static void save_chunk_info(struct expression *left, struct expression *right)
1073 {
1074 struct var_sym_list *vsl;
1075 struct var_sym *vs;
1076 struct expression *add_expr;
1077 struct symbol *type;
1078 sval_t sval;
1079 char *name;
1080 struct symbol *sym;
1081
1082 if (right->type != EXPR_BINOP || right->op != '-')
1083 return;
1084 if (!get_value(right->left, &sval))
1085 return;
1086 if (!expr_to_sym(right->right))
1087 return;
1088
1089 add_expr = binop_expression(left, '+', right->right);
1090 type = get_type(add_expr);
1091 if (!type)
1092 return;
1093 name = expr_to_chunk_sym_vsl(add_expr, &sym, &vsl);
1094 if (!name || !vsl)
1095 goto free;
1096 FOR_EACH_PTR(vsl, vs) {
1097 store_link(link_id, vs->var, vs->sym, name, sym);
1098 } END_FOR_EACH_PTR(vs);
1099
1100 set_state(SMATCH_EXTRA, name, sym, alloc_estate_sval(sval_cast(type, sval)));
1101 free:
1102 free_string(name);
1103 }
1104
1105 static void do_array_assign(struct expression *left, int op, struct expression *right)
1106 {
1107 struct range_list *rl;
1108
1109 if (op == '=') {
1110 get_absolute_rl(right, &rl);
1111 rl = cast_rl(get_type(left), rl);
1112 } else {
1113 rl = alloc_whole_rl(get_type(left));
1114 }
1115
1116 set_extra_array_mod(left, alloc_estate_rl(rl));
1117 }
1118
1119 static void match_vanilla_assign(struct expression *left, struct expression *right)
1120 {
1121 struct range_list *orig_rl = NULL;
1122 struct range_list *rl = NULL;
1123 struct symbol *right_sym;
1124 struct symbol *left_type;
1125 struct symbol *right_type;
1126 char *right_name = NULL;
1127 struct symbol *sym;
1128 char *name;
1129 sval_t sval, max;
1130 struct smatch_state *state;
1131 int comparison;
1132
1133 if (is_struct(left))
1134 return;
1135
1136 if (expr_equiv(left, right))
1137 return;
1138
1139 save_chunk_info(left, right);
1140
1141 name = expr_to_var_sym(left, &sym);
1142 if (!name) {
1143 if (chunk_has_array(left))
1144 do_array_assign(left, '=', right);
1145 return;
1146 }
1147
1148 left_type = get_type(left);
1149 right_type = get_type(right);
1150
1151 right_name = expr_to_var_sym(right, &right_sym);
1152
1153 if (!__in_fake_assign &&
1154 !(right->type == EXPR_PREOP && right->op == '&') &&
1155 right_name && right_sym &&
1156 values_fit_type(left, strip_expr(right)) &&
1157 !has_symbol(right, sym)) {
1158 set_equiv(left, right);
1159 goto free;
1160 }
1161
1162 if (get_implied_value(right, &sval)) {
1163 state = alloc_estate_sval(sval_cast(left_type, sval));
1164 goto done;
1165 }
1166
1167 if (__in_fake_assign || is_fake_var(left)) {
1168 struct smatch_state *right_state;
1169 struct range_list *rl;
1170
1171 right_state = get_state(SMATCH_EXTRA, right_name, right_sym);
1172 if (right_state) {
1173 state = clone_estate_cast(left_type, right_state);
1174 goto done;
1175 }
1176
1177 if (get_implied_rl(right, &rl)) {
1178 rl = cast_rl(left_type, rl);
1179 state = alloc_estate_rl(rl);
1180 goto done;
1181 }
1182
1183 rl = alloc_whole_rl(right_type);
1184 rl = cast_rl(left_type, rl);
1185 state = alloc_estate_rl(rl);
1186 goto done;
1187 }
1188
1189 comparison = get_comparison_no_extra(left, right);
1190 if (comparison) {
1191 comparison = flip_comparison(comparison);
1192 get_implied_rl(left, &orig_rl);
1193 }
1194
1195 if (get_implied_rl(right, &rl)) {
1196 rl = cast_rl(left_type, rl);
1197 if (orig_rl)
1198 filter_by_comparison(&rl, comparison, orig_rl);
1199 state = alloc_estate_rl(rl);
1200 if (get_hard_max(right, &max)) {
1201 estate_set_hard_max(state);
1202 estate_set_fuzzy_max(state, max);
1203 }
1204 } else {
1205 rl = alloc_whole_rl(right_type);
1206 rl = cast_rl(left_type, rl);
1207 if (orig_rl)
1208 filter_by_comparison(&rl, comparison, orig_rl);
1209 state = alloc_estate_rl(rl);
1210 }
1211
1212 done:
1213 set_extra_mod(name, sym, left, state);
1214 free:
1215 free_string(right_name);
1216 }
1217
1218 static void match_assign(struct expression *expr)
1219 {
1220 struct range_list *rl = NULL;
1221 struct expression *left;
1222 struct expression *right;
1223 struct expression *binop_expr;
1224 struct symbol *left_type;
1225 struct symbol *sym;
1226 char *name;
1227
1228 left = strip_expr(expr->left);
1229
1230 right = strip_parens(expr->right);
1231 if (right->type == EXPR_CALL && sym_name_is("__builtin_expect", right->fn))
1232 right = get_argument_from_call_expr(right->args, 0);
1233 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
1234 right = strip_parens(right->left);
1235
1236 if (expr->op == '=' && is_condition(expr->right))
1237 return; /* handled in smatch_condition.c */
1238 if (expr->op == '=' && right->type == EXPR_CALL &&
1239 !is_fake_call(right))
1240 return; /* handled in smatch_function_hooks.c */
1241 if (expr->op == '=') {
1242 match_vanilla_assign(left, right);
1243 return;
1244 }
1245
1246 name = expr_to_var_sym(left, &sym);
1247 if (!name)
1248 return;
1249
1250 left_type = get_type(left);
1251
1252 switch (expr->op) {
1253 case SPECIAL_ADD_ASSIGN:
1254 case SPECIAL_SUB_ASSIGN:
1255 case SPECIAL_AND_ASSIGN:
1256 case SPECIAL_MOD_ASSIGN:
1257 case SPECIAL_SHL_ASSIGN:
1258 case SPECIAL_SHR_ASSIGN:
1259 case SPECIAL_OR_ASSIGN:
1260 case SPECIAL_XOR_ASSIGN:
1261 case SPECIAL_MUL_ASSIGN:
1262 case SPECIAL_DIV_ASSIGN:
1263 binop_expr = binop_expression(expr->left,
1264 op_remove_assign(expr->op),
1265 expr->right);
1266 get_absolute_rl(binop_expr, &rl);
1267 rl = cast_rl(left_type, rl);
1268 if (inside_loop()) {
1269 if (expr->op == SPECIAL_ADD_ASSIGN)
1270 add_range(&rl, rl_max(rl), sval_type_max(rl_type(rl)));
1271
1272 if (expr->op == SPECIAL_SUB_ASSIGN &&
1273 !sval_is_negative(rl_min(rl))) {
1274 sval_t zero = { .type = rl_type(rl) };
1275
1276 add_range(&rl, rl_min(rl), zero);
1277 }
1278 }
1279 set_extra_mod(name, sym, left, alloc_estate_rl(rl));
1280 goto free;
1281 }
1282 set_extra_mod(name, sym, left, alloc_estate_whole(left_type));
1283 free:
1284 free_string(name);
1285 }
1286
1287 static struct smatch_state *increment_state(struct smatch_state *state)
1288 {
1289 sval_t min = estate_min(state);
1290 sval_t max = estate_max(state);
1291
1292 if (!estate_rl(state))
1293 return NULL;
1294
1295 if (inside_loop())
1296 max = sval_type_max(max.type);
1297
1298 if (!sval_is_min(min) && !sval_is_max(min))
1299 min.value++;
1300 if (!sval_is_min(max) && !sval_is_max(max))
1301 max.value++;
1302 return alloc_estate_range(min, max);
1303 }
1304
1305 static struct smatch_state *decrement_state(struct smatch_state *state)
1306 {
1307 sval_t min = estate_min(state);
1308 sval_t max = estate_max(state);
1309
1310 if (!estate_rl(state))
1311 return NULL;
1312
1313 if (inside_loop())
1314 min = sval_type_min(min.type);
1315
1316 if (!sval_is_min(min) && !sval_is_max(min))
1317 min.value--;
1318 if (!sval_is_min(max) && !sval_is_max(max))
1319 max.value--;
1320 return alloc_estate_range(min, max);
1321 }
1322
1323 static void clear_pointed_at_state(struct expression *expr)
1324 {
1325 struct symbol *type;
1326
1327 /*
1328 * ALERT: This is sort of a mess. If it's is a struct assigment like
1329 * "foo = bar;", then that's handled by smatch_struct_assignment.c.
1330 * the same thing for p++ where "p" is a struct. Most modifications
1331 * are handled by the assignment hook or the db. Smatch_extra.c doesn't
1332 * use smatch_modification.c because we have to get the ordering right
1333 * or something. So if you have p++ where p is a pointer to a standard
1334 * c type then we handle that here. What a mess.
1335 */
1336 expr = strip_expr(expr);
1337 type = get_type(expr);
1338 if (!type || type->type != SYM_PTR)
1339 return;
1340 type = get_real_base_type(type);
1341 if (!type || type->type != SYM_BASETYPE)
1342 return;
1343 set_extra_expr_nomod(deref_expression(expr), alloc_estate_whole(type));
1344 }
1345
1346 static void unop_expr(struct expression *expr)
1347 {
1348 struct smatch_state *state;
1349
1350 if (expr->smatch_flags & Handled)
1351 return;
1352
1353 switch (expr->op) {
1354 case SPECIAL_INCREMENT:
1355 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1356 state = increment_state(state);
1357 if (!state)
1358 state = alloc_estate_whole(get_type(expr));
1359 set_extra_expr_mod(expr->unop, state);
1360 clear_pointed_at_state(expr->unop);
1361 break;
1362 case SPECIAL_DECREMENT:
1363 state = get_state_expr(SMATCH_EXTRA, expr->unop);
1364 state = decrement_state(state);
1365 if (!state)
1366 state = alloc_estate_whole(get_type(expr));
1367 set_extra_expr_mod(expr->unop, state);
1368 clear_pointed_at_state(expr->unop);
1369 break;
1370 default:
1371 return;
1372 }
1373 }
1374
1375 static void asm_expr(struct statement *stmt)
1376 {
1377 struct asm_operand *op;
1378 struct symbol *type;
1379
1380 FOR_EACH_PTR(stmt->asm_outputs, op) {
1381 type = get_type(strip_expr(op->expr));
1382 set_extra_expr_mod(op->expr, alloc_estate_whole(type));
1383 } END_FOR_EACH_PTR(op);
1384 }
1385
1386 static void check_dereference(struct expression *expr)
1387 {
1388 struct smatch_state *state;
1389
1390 if (__in_fake_assign)
1391 return;
1392 if (outside_of_function())
1393 return;
1394 state = get_extra_state(expr);
1395 if (state) {
1396 struct range_list *rl;
1397
1398 rl = rl_intersection(estate_rl(state), valid_ptr_rl);
1399 if (rl_equiv(rl, estate_rl(state)))
1400 return;
1401 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1402 } else {
1403 struct range_list *rl;
1404
1405 if (get_mtag_rl(expr, &rl))
1406 rl = rl_intersection(rl, valid_ptr_rl);
1407 else
1408 rl = clone_rl(valid_ptr_rl);
1409
1410 __no_limits++;
1411 set_extra_expr_nomod(expr, alloc_estate_rl(rl));
1412 __no_limits--;
1413 }
1414 }
1415
1416 static void match_dereferences(struct expression *expr)
1417 {
1418 if (expr->type != EXPR_PREOP)
1419 return;
1420 if (getting_address(expr))
1421 return;
1422 /* it's saying that foo[1] = bar dereferences foo[1] */
1423 if (is_array(expr))
1424 return;
1425 check_dereference(expr->unop);
1426 }
1427
1428 static void match_pointer_as_array(struct expression *expr)
1429 {
1430 if (!is_array(expr))
1431 return;
1432 check_dereference(get_array_base(expr));
1433 }
1434
1435 static void find_dereferences(struct expression *expr)
1436 {
1437 while (expr->type == EXPR_PREOP) {
1438 if (expr->op == '*')
1439 check_dereference(expr->unop);
1440 expr = strip_expr(expr->unop);
1441 }
1442 }
1443
1444 static void set_param_dereferenced(struct expression *call, struct expression *arg, char *key, char *unused)
1445 {
1446 struct symbol *sym;
1447 char *name;
1448
1449 if (strcmp(key, "$") == 0 && arg->type == EXPR_PREOP && arg->op == '&') {
1450 struct expression *tmp;
1451
1452 tmp = strip_expr(arg->unop);
1453 if (tmp->type == EXPR_DEREF) {
1454 tmp = strip_expr(tmp->deref);
1455 if (tmp->type == EXPR_PREOP && tmp->op == '*')
1456 arg = strip_expr(tmp->unop);
1457 }
1458 }
1459
1460 name = get_variable_from_key(arg, key, &sym);
1461 if (name && sym) {
1462 struct smatch_state *orig, *new;
1463 struct range_list *rl;
1464
1465 orig = get_state(SMATCH_EXTRA, name, sym);
1466 if (orig) {
1467 rl = rl_intersection(estate_rl(orig),
1468 alloc_rl(valid_ptr_min_sval,
1469 valid_ptr_max_sval));
1470 new = alloc_estate_rl(rl);
1471 } else {
1472 new = alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval);
1473 }
1474
1475 if (!orig)
1476 __no_limits++;
1477 set_extra_nomod(name, sym, NULL, new);
1478 if (!orig)
1479 __no_limits--;
1480 }
1481 free_string(name);
1482
1483 find_dereferences(arg);
1484 }
1485
1486 static sval_t add_one(sval_t sval)
1487 {
1488 sval.value++;
1489 return sval;
1490 }
1491
1492 static int handle_postop_inc(struct expression *left, int op, struct expression *right)
1493 {
1494 struct statement *stmt;
1495 struct expression *cond;
1496 struct smatch_state *true_state, *false_state;
1497 struct symbol *type;
1498 sval_t start;
1499 sval_t limit;
1500
1501 /*
1502 * If we're decrementing here then that's a canonical while count down
1503 * so it's handled already. We're only handling loops like:
1504 * i = 0;
1505 * do { ... } while (i++ < 3);
1506 */
1507
1508 if (left->type != EXPR_POSTOP || left->op != SPECIAL_INCREMENT)
1509 return 0;
1510
1511 stmt = __cur_stmt->parent;
1512 if (!stmt)
1513 return 0;
1514 if (stmt->type == STMT_COMPOUND)
1515 stmt = stmt->parent;
1516 if (!stmt || stmt->type != STMT_ITERATOR || !stmt->iterator_post_condition)
1517 return 0;
1518
1519 cond = strip_expr(stmt->iterator_post_condition);
1520 if (cond->type != EXPR_COMPARE || cond->op != op)
1521 return 0;
1522 if (left != strip_expr(cond->left) || right != strip_expr(cond->right))
1523 return 0;
1524
1525 if (!get_implied_value(left->unop, &start))
1526 return 0;
1527 if (!get_implied_value(right, &limit))
1528 return 0;
1529 type = get_type(left->unop);
1530 limit = sval_cast(type, limit);
1531 if (sval_cmp(start, limit) > 0)
1532 return 0;
1533
1534 switch (op) {
1535 case '<':
1536 case SPECIAL_UNSIGNED_LT:
1537 break;
1538 case SPECIAL_LTE:
1539 case SPECIAL_UNSIGNED_LTE:
1540 limit = add_one(limit);
1541 default:
1542 return 0;
1543
1544 }
1545
1546 true_state = alloc_estate_range(add_one(start), limit);
1547 false_state = alloc_estate_range(add_one(limit), add_one(limit));
1548
1549 /* Currently we just discard the false state but when two passes is
1550 * implimented correctly then it will use it.
1551 */
1552
1553 set_extra_expr_true_false(left->unop, true_state, false_state);
1554
1555 return 1;
1556 }
1557
1558 bool is_impossible_variable(struct expression *expr)
1559 {
1560 struct smatch_state *state;
1561
1562 state = get_extra_state(expr);
1563 if (state && !estate_rl(state))
1564 return true;
1565 return false;
1566 }
1567
1568 static bool in_macro(struct expression *left, struct expression *right)
1569 {
1570 if (!left || !right)
1571 return 0;
1572 if (left->pos.line != right->pos.line || left->pos.pos != right->pos.pos)
1573 return 0;
1574 if (get_macro_name(left->pos))
1575 return 1;
1576 return 0;
1577 }
1578
1579 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
1580 {
1581 struct smatch_state *left_state_orig, *right_state_orig;
1582 struct range_list *left_orig;
1583 struct range_list *left_true;
1584 struct range_list *left_false;
1585 struct range_list *right_orig;
1586 struct range_list *right_true;
1587 struct range_list *right_false;
1588 struct smatch_state *left_true_state;
1589 struct smatch_state *left_false_state;
1590 struct smatch_state *right_true_state;
1591 struct smatch_state *right_false_state;
1592 sval_t dummy, hard_max;
1593 int left_postop = 0;
1594 int right_postop = 0;
1595
1596 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
1597 if (left->type == EXPR_POSTOP) {
1598 left->smatch_flags |= Handled;
1599 left_postop = left->op;
1600 if (handle_postop_inc(left, op, right))
1601 return;
1602 }
1603 left = strip_parens(left->unop);
1604 }
1605 while (left->type == EXPR_ASSIGNMENT)
1606 left = strip_parens(left->left);
1607
1608 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
1609 if (right->type == EXPR_POSTOP) {
1610 right->smatch_flags |= Handled;
1611 right_postop = right->op;
1612 }
1613 right = strip_parens(right->unop);
1614 }
1615
1616 if (is_impossible_variable(left) || is_impossible_variable(right))
1617 return;
1618
1619 left_state_orig = get_extra_state(left);
1620 get_real_absolute_rl(left, &left_orig);
1621 left_orig = cast_rl(type, left_orig);
1622
1623 right_state_orig = get_extra_state(right);
1624 get_real_absolute_rl(right, &right_orig);
1625 right_orig = cast_rl(type, right_orig);
1626
1627 split_comparison_rl(left_orig, op, right_orig, &left_true, &left_false, &right_true, &right_false);
1628
1629 left_true = rl_truncate_cast(get_type(strip_expr(left)), left_true);
1630 left_false = rl_truncate_cast(get_type(strip_expr(left)), left_false);
1631 right_true = rl_truncate_cast(get_type(strip_expr(right)), right_true);
1632 right_false = rl_truncate_cast(get_type(strip_expr(right)), right_false);
1633
1634 if (!left_true || !left_false) {
1635 struct range_list *tmp_true, *tmp_false;
1636
1637 split_comparison_rl(alloc_whole_rl(type), op, right_orig, &tmp_true, &tmp_false, NULL, NULL);
1638 tmp_true = rl_truncate_cast(get_type(strip_expr(left)), tmp_true);
1639 tmp_false = rl_truncate_cast(get_type(strip_expr(left)), tmp_false);
1640 if (tmp_true && tmp_false)
1641 __save_imaginary_state(left, tmp_true, tmp_false);
1642 }
1643
1644 if (!right_true || !right_false) {
1645 struct range_list *tmp_true, *tmp_false;
1646
1647 split_comparison_rl(alloc_whole_rl(type), op, right_orig, NULL, NULL, &tmp_true, &tmp_false);
1648 tmp_true = rl_truncate_cast(get_type(strip_expr(right)), tmp_true);
1649 tmp_false = rl_truncate_cast(get_type(strip_expr(right)), tmp_false);
1650 if (tmp_true && tmp_false)
1651 __save_imaginary_state(right, tmp_true, tmp_false);
1652 }
1653
1654 left_true_state = alloc_estate_rl(left_true);
1655 left_false_state = alloc_estate_rl(left_false);
1656 right_true_state = alloc_estate_rl(right_true);
1657 right_false_state = alloc_estate_rl(right_false);
1658
1659 switch (op) {
1660 case '<':
1661 case SPECIAL_UNSIGNED_LT:
1662 case SPECIAL_UNSIGNED_LTE:
1663 case SPECIAL_LTE:
1664 if (get_hard_max(right, &dummy) && !in_macro(left, right))
1665 estate_set_hard_max(left_true_state);
1666 if (get_hard_max(left, &dummy) && !in_macro(left, right))
1667 estate_set_hard_max(right_false_state);
1668 break;
1669 case '>':
1670 case SPECIAL_UNSIGNED_GT:
1671 case SPECIAL_UNSIGNED_GTE:
1672 case SPECIAL_GTE:
1673 if (get_hard_max(left, &dummy) && !in_macro(left, right))
1674 estate_set_hard_max(right_true_state);
1675 if (get_hard_max(right, &dummy) && !in_macro(left, right))
1676 estate_set_hard_max(left_false_state);
1677 break;
1678 }
1679
1680 switch (op) {
1681 case '<':
1682 case SPECIAL_UNSIGNED_LT:
1683 case SPECIAL_UNSIGNED_LTE:
1684 case SPECIAL_LTE:
1685 if (get_hard_max(right, &hard_max)) {
1686 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1687 hard_max.value--;
1688 estate_set_fuzzy_max(left_true_state, hard_max);
1689 }
1690 if (get_implied_value(right, &hard_max)) {
1691 if (op == SPECIAL_UNSIGNED_LTE ||
1692 op == SPECIAL_LTE)
1693 hard_max.value++;
1694 estate_set_fuzzy_max(left_false_state, hard_max);
1695 }
1696 if (get_hard_max(left, &hard_max)) {
1697 if (op == SPECIAL_UNSIGNED_LTE ||
1698 op == SPECIAL_LTE)
1699 hard_max.value--;
1700 estate_set_fuzzy_max(right_false_state, hard_max);
1701 }
1702 if (get_implied_value(left, &hard_max)) {
1703 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1704 hard_max.value++;
1705 estate_set_fuzzy_max(right_true_state, hard_max);
1706 }
1707 break;
1708 case '>':
1709 case SPECIAL_UNSIGNED_GT:
1710 case SPECIAL_UNSIGNED_GTE:
1711 case SPECIAL_GTE:
1712 if (get_hard_max(left, &hard_max)) {
1713 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1714 hard_max.value--;
1715 estate_set_fuzzy_max(right_true_state, hard_max);
1716 }
1717 if (get_implied_value(left, &hard_max)) {
1718 if (op == SPECIAL_UNSIGNED_GTE ||
1719 op == SPECIAL_GTE)
1720 hard_max.value++;
1721 estate_set_fuzzy_max(right_false_state, hard_max);
1722 }
1723 if (get_hard_max(right, &hard_max)) {
1724 if (op == SPECIAL_UNSIGNED_LTE ||
1725 op == SPECIAL_LTE)
1726 hard_max.value--;
1727 estate_set_fuzzy_max(left_false_state, hard_max);
1728 }
1729 if (get_implied_value(right, &hard_max)) {
1730 if (op == '>' ||
1731 op == SPECIAL_UNSIGNED_GT)
1732 hard_max.value++;
1733 estate_set_fuzzy_max(left_true_state, hard_max);
1734 }
1735 break;
1736 case SPECIAL_EQUAL:
1737 if (get_hard_max(left, &hard_max))
1738 estate_set_fuzzy_max(right_true_state, hard_max);
1739 if (get_hard_max(right, &hard_max))
1740 estate_set_fuzzy_max(left_true_state, hard_max);
1741 break;
1742 }
1743
1744 if (get_hard_max(left, &hard_max)) {
1745 estate_set_hard_max(left_true_state);
1746 estate_set_hard_max(left_false_state);
1747 }
1748 if (get_hard_max(right, &hard_max)) {
1749 estate_set_hard_max(right_true_state);
1750 estate_set_hard_max(right_false_state);
1751 }
1752
1753 if (left_postop == SPECIAL_INCREMENT) {
1754 left_true_state = increment_state(left_true_state);
1755 left_false_state = increment_state(left_false_state);
1756 }
1757 if (left_postop == SPECIAL_DECREMENT) {
1758 left_true_state = decrement_state(left_true_state);
1759 left_false_state = decrement_state(left_false_state);
1760 }
1761 if (right_postop == SPECIAL_INCREMENT) {
1762 right_true_state = increment_state(right_true_state);
1763 right_false_state = increment_state(right_false_state);
1764 }
1765 if (right_postop == SPECIAL_DECREMENT) {
1766 right_true_state = decrement_state(right_true_state);
1767 right_false_state = decrement_state(right_false_state);
1768 }
1769
1770 if (estate_rl(left_true_state) && estates_equiv(left_true_state, left_false_state)) {
1771 left_true_state = NULL;
1772 left_false_state = NULL;
1773 }
1774
1775 if (estate_rl(right_true_state) && estates_equiv(right_true_state, right_false_state)) {
1776 right_true_state = NULL;
1777 right_false_state = NULL;
1778 }
1779
1780 /* Don't introduce new states for known true/false conditions */
1781 if (rl_equiv(estate_rl(left_state_orig), estate_rl(left_true_state)))
1782 left_true_state = NULL;
1783 if (rl_equiv(estate_rl(left_state_orig), estate_rl(left_false_state)))
1784 left_false_state = NULL;
1785 if (rl_equiv(estate_rl(right_state_orig), estate_rl(right_true_state)))
1786 right_true_state = NULL;
1787 if (rl_equiv(estate_rl(right_state_orig), estate_rl(right_false_state)))
1788 right_false_state = NULL;
1789
1790 set_extra_expr_true_false(left, left_true_state, left_false_state);
1791 set_extra_expr_true_false(right, right_true_state, right_false_state);
1792 }
1793
1794 static int is_simple_math(struct expression *expr)
1795 {
1796 if (!expr)
1797 return 0;
1798 if (expr->type != EXPR_BINOP)
1799 return 0;
1800 switch (expr->op) {
1801 case '+':
1802 case '-':
1803 case '*':
1804 return 1;
1805 }
1806 return 0;
1807 }
1808
1809 static int flip_op(int op)
1810 {
1811 /* We only care about simple math */
1812 switch (op) {
1813 case '+':
1814 return '-';
1815 case '-':
1816 return '+';
1817 case '*':
1818 return '/';
1819 }
1820 return 0;
1821 }
1822
1823 static void move_known_to_rl(struct expression **expr_p, struct range_list **rl_p)
1824 {
1825 struct expression *expr = *expr_p;
1826 struct range_list *rl = *rl_p;
1827 sval_t sval;
1828
1829 if (!is_simple_math(expr))
1830 return;
1831
1832 if (get_implied_value(expr->right, &sval)) {
1833 *expr_p = expr->left;
1834 *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
1835 move_known_to_rl(expr_p, rl_p);
1836 return;
1837 }
1838 if (expr->op == '-')
1839 return;
1840 if (get_implied_value(expr->left, &sval)) {
1841 *expr_p = expr->right;
1842 *rl_p = rl_binop(rl, flip_op(expr->op), alloc_rl(sval, sval));
1843 move_known_to_rl(expr_p, rl_p);
1844 return;
1845 }
1846 }
1847
1848 static void move_known_values(struct expression **left_p, struct expression **right_p)
1849 {
1850 struct expression *left = *left_p;
1851 struct expression *right = *right_p;
1852 sval_t sval, dummy;
1853
1854 if (get_implied_value(left, &sval)) {
1855 if (!is_simple_math(right))
1856 return;
1857 if (get_implied_value(right, &dummy))
1858 return;
1859 if (right->op == '*') {
1860 sval_t divisor;
1861
1862 if (!get_value(right->right, &divisor))
1863 return;
1864 if (divisor.value == 0)
1865 return;
1866 *left_p = binop_expression(left, invert_op(right->op), right->right);
1867 *right_p = right->left;
1868 return;
1869 }
1870 if (right->op == '+' && get_value(right->left, &sval)) {
1871 *left_p = binop_expression(left, invert_op(right->op), right->left);
1872 *right_p = right->right;
1873 return;
1874 }
1875 if (get_value(right->right, &sval)) {
1876 *left_p = binop_expression(left, invert_op(right->op), right->right);
1877 *right_p = right->left;
1878 return;
1879 }
1880 return;
1881 }
1882 if (get_implied_value(right, &sval)) {
1883 if (!is_simple_math(left))
1884 return;
1885 if (get_implied_value(left, &dummy))
1886 return;
1887 if (left->op == '*') {
1888 sval_t divisor;
1889
1890 if (!get_value(left->right, &divisor))
1891 return;
1892 if (divisor.value == 0)
1893 return;
1894 *right_p = binop_expression(right, invert_op(left->op), left->right);
1895 *left_p = left->left;
1896 return;
1897 }
1898 if (left->op == '+' && get_value(left->left, &sval)) {
1899 *right_p = binop_expression(right, invert_op(left->op), left->left);
1900 *left_p = left->right;
1901 return;
1902 }
1903
1904 if (get_value(left->right, &sval)) {
1905 *right_p = binop_expression(right, invert_op(left->op), left->right);
1906 *left_p = left->left;
1907 return;
1908 }
1909 return;
1910 }
1911 }
1912
1913 /*
1914 * The reason for do_simple_algebra() is to solve things like:
1915 * if (foo > 66 || foo + bar > 64) {
1916 * "foo" is not really a known variable so it won't be handled by
1917 * move_known_variables() but it's a super common idiom.
1918 *
1919 */
1920 static int do_simple_algebra(struct expression **left_p, struct expression **right_p)
1921 {
1922 struct expression *left = *left_p;
1923 struct expression *right = *right_p;
1924 struct range_list *rl;
1925 sval_t tmp;
1926
1927 if (left->type != EXPR_BINOP || left->op != '+')
1928 return 0;
1929 if (can_integer_overflow(get_type(left), left))
1930 return 0;
1931 if (!get_implied_value(right, &tmp))
1932 return 0;
1933
1934 if (!get_implied_value(left->left, &tmp) &&
1935 get_implied_rl(left->left, &rl) &&
1936 !is_whole_rl(rl)) {
1937 *right_p = binop_expression(right, '-', left->left);
1938 *left_p = left->right;
1939 return 1;
1940 }
1941 if (!get_implied_value(left->right, &tmp) &&
1942 get_implied_rl(left->right, &rl) &&
1943 !is_whole_rl(rl)) {
1944 *right_p = binop_expression(right, '-', left->right);
1945 *left_p = left->left;
1946 return 1;
1947 }
1948
1949 return 0;
1950 }
1951
1952 static int match_func_comparison(struct expression *expr)
1953 {
1954 struct expression *left = strip_expr(expr->left);
1955 struct expression *right = strip_expr(expr->right);
1956
1957 if (left->type == EXPR_CALL || right->type == EXPR_CALL) {
1958 // TODO: faked_assign this should be handled as a fake assignment instead
1959 function_comparison(left, expr->op, right);
1960 return 1;
1961 }
1962
1963 return 0;
1964 }
1965
1966 /* Handle conditions like "if (foo + bar < foo) {" */
1967 static int handle_integer_overflow_test(struct expression *expr)
1968 {
1969 struct expression *left, *right;
1970 struct symbol *type;
1971 sval_t left_min, right_min, min, max;
1972
1973 if (expr->op != '<' && expr->op != SPECIAL_UNSIGNED_LT)
1974 return 0;
1975
1976 left = strip_parens(expr->left);
1977 right = strip_parens(expr->right);
1978
1979 if (left->op != '+')
1980 return 0;
1981
1982 type = get_type(expr);
1983 if (!type)
1984 return 0;
1985 if (type_positive_bits(type) == 32) {
1986 max.type = &uint_ctype;
1987 max.uvalue = (unsigned int)-1;
1988 } else if (type_positive_bits(type) == 64) {
1989 max.type = &ulong_ctype;
1990 max.value = (unsigned long long)-1;
1991 } else {
1992 return 0;
1993 }
1994
1995 if (!expr_equiv(left->left, right) && !expr_equiv(left->right, right))
1996 return 0;
1997
1998 get_absolute_min(left->left, &left_min);
1999 get_absolute_min(left->right, &right_min);
2000 min = sval_binop(left_min, '+', right_min);
2001
2002 type = get_type(left);
2003 min = sval_cast(type, min);
2004 max = sval_cast(type, max);
2005
2006 set_extra_chunk_true_false(left, NULL, alloc_estate_range(min, max));
2007 return 1;
2008 }
2009
2010 static void match_comparison(struct expression *expr)
2011 {
2012 struct expression *left_orig = strip_parens(expr->left);
2013 struct expression *right_orig = strip_parens(expr->right);
2014 struct expression *left, *right, *tmp;
2015 struct expression *prev;
2016 struct symbol *type;
2017 int redo, count;
2018
2019 if (match_func_comparison(expr))
2020 return;
2021
2022 type = get_type(expr);
2023 if (!type)
2024 type = &llong_ctype;
2025
2026 if (handle_integer_overflow_test(expr))
2027 return;
2028
2029 left = left_orig;
2030 right = right_orig;
2031 move_known_values(&left, &right);
2032 handle_comparison(type, left, expr->op, right);
2033
2034 left = left_orig;
2035 right = right_orig;
2036 if (do_simple_algebra(&left, &right))
2037 handle_comparison(type, left, expr->op, right);
2038
2039 prev = get_assigned_expr(left_orig);
2040 if (is_simple_math(prev) && !has_variable(prev, left_orig)) {
2041 left = prev;
2042 right = right_orig;
2043 move_known_values(&left, &right);
2044 handle_comparison(type, left, expr->op, right);
2045 }
2046
2047 prev = get_assigned_expr(right_orig);
2048 if (is_simple_math(prev) && !has_variable(prev, right_orig)) {
2049 left = left_orig;
2050 right = prev;
2051 move_known_values(&left, &right);
2052 handle_comparison(type, left, expr->op, right);
2053 }
2054
2055 redo = 0;
2056 left = left_orig;
2057 right = right_orig;
2058 if (get_last_expr_from_expression_stmt(left_orig)) {
2059 left = get_last_expr_from_expression_stmt(left_orig);
2060 redo = 1;
2061 }
2062 if (get_last_expr_from_expression_stmt(right_orig)) {
2063 right = get_last_expr_from_expression_stmt(right_orig);
2064 redo = 1;
2065 }
2066
2067 if (!redo)
2068 return;
2069
2070 count = 0;
2071 while ((tmp = get_assigned_expr(left))) {
2072 if (count++ > 3)
2073 break;
2074 left = strip_expr(tmp);
2075 }
2076 count = 0;
2077 while ((tmp = get_assigned_expr(right))) {
2078 if (count++ > 3)
2079 break;
2080 right = strip_expr(tmp);
2081 }
2082
2083 handle_comparison(type, left, expr->op, right);
2084 }
2085
2086 static sval_t get_high_mask(sval_t known)
2087 {
2088 sval_t ret;
2089 int i;
2090
2091 ret = known;
2092 ret.value = 0;
2093
2094 for (i = type_bits(known.type) - 1; i >= 0; i--) {
2095 if (known.uvalue & (1ULL << i))
2096 ret.uvalue |= (1ULL << i);
2097 else
2098 return ret;
2099
2100 }
2101 return ret;
2102 }
2103
2104 static bool handle_bit_test(struct expression *expr)
2105 {
2106 struct range_list *orig_rl, *rlt, *rlf, *true_rl, *false_rl;
2107 struct expression *shift, *mask, *var;
2108 struct bit_info *bit_info;
2109 sval_t sval;
2110 sval_t high = { .type = &int_ctype };
2111 sval_t low = { .type = &int_ctype };
2112
2113 shift = strip_expr(expr->right);
2114 mask = strip_expr(expr->left);
2115 if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT) {
2116 shift = strip_expr(expr->left);
2117 mask = strip_expr(expr->right);
2118 if (shift->type != EXPR_BINOP || shift->op != SPECIAL_LEFTSHIFT)
2119 return false;
2120 }
2121 if (!get_implied_value(shift->left, &sval) || sval.value != 1)
2122 return false;
2123 var = strip_expr(shift->right);
2124
2125 bit_info = get_bit_info(mask);
2126 if (!bit_info)
2127 return false;
2128 if (!bit_info->possible){
2129 set_true_false_states_expr(my_id, var, alloc_estate_empty(), NULL);
2130 return false;
2131 }
2132
2133 get_absolute_rl(var, &orig_rl);
2134 if (sval_is_negative(rl_min(orig_rl)) ||
2135 rl_max(orig_rl).uvalue > type_bits(get_type(shift->left)))
2136 return false;
2137
2138 low.value = ffsll(bit_info->possible) - 1;
2139 high.value = sm_fls64(bit_info->possible) - 1;
2140 rlt = alloc_rl(low, high);
2141 rlt = cast_rl(get_type(var), rlt);
2142 true_rl = rl_intersection(orig_rl, rlt);
2143
2144 low.value = ffsll(bit_info->set) - 1;
2145 high.value = sm_fls64(bit_info->set) - 1;
2146 rlf = alloc_rl(low, high);
2147 rlf = cast_rl(get_type(var), rlf);
2148 false_rl = rl_filter(orig_rl, rlf);
2149
2150 set_extra_expr_true_false(var, alloc_estate_rl(true_rl), alloc_estate_rl(false_rl));
2151
2152 return true;
2153 }
2154
2155 static void handle_AND_op(struct expression *var, sval_t known)
2156 {
2157 struct range_list *orig_rl;
2158 struct range_list *true_rl = NULL;
2159 struct range_list *false_rl = NULL;
2160 int bit;
2161 sval_t low_mask = known;
2162 sval_t high_mask;
2163 sval_t max;
2164
2165 get_absolute_rl(var, &orig_rl);
2166
2167 if (known.value > 0) {
2168 bit = ffsll(known.value) - 1;
2169 low_mask.uvalue = (1ULL << bit) - 1;
2170 true_rl = remove_range(orig_rl, sval_type_val(known.type, 0), low_mask);
2171 }
2172 high_mask = get_high_mask(known);
2173 if (high_mask.value) {
2174 bit = ffsll(high_mask.value) - 1;
2175 low_mask.uvalue = (1ULL << bit) - 1;
2176
2177 false_rl = orig_rl;
2178 if (sval_is_negative(rl_min(orig_rl)))
2179 false_rl = remove_range(false_rl, sval_type_min(known.type), sval_type_val(known.type, -1));
2180 false_rl = remove_range(false_rl, low_mask, sval_type_max(known.type));
2181 if (type_signed(high_mask.type) && type_unsigned(rl_type(false_rl))) {
2182 false_rl = remove_range(false_rl,
2183 sval_type_val(rl_type(false_rl), sval_type_max(known.type).uvalue),
2184 sval_type_val(rl_type(false_rl), -1));
2185 }
2186 } else if (known.value == 1 &&
2187 get_hard_max(var, &max) &&
2188 sval_cmp(max, rl_max(orig_rl)) == 0 &&
2189 max.value & 1) {
2190 false_rl = remove_range(orig_rl, max, max);
2191 }
2192 set_extra_expr_true_false(var,
2193 true_rl ? alloc_estate_rl(true_rl) : NULL,
2194 false_rl ? alloc_estate_rl(false_rl) : NULL);
2195 }
2196
2197 static void handle_AND_condition(struct expression *expr)
2198 {
2199 sval_t known;
2200
2201 if (handle_bit_test(expr))
2202 return;
2203
2204 if (get_implied_value(expr->left, &known))
2205 handle_AND_op(expr->right, known);
2206 else if (get_implied_value(expr->right, &known))
2207 handle_AND_op(expr->left, known);
2208 }
2209
2210 static void handle_MOD_condition(struct expression *expr)
2211 {
2212 struct range_list *orig_rl;
2213 struct range_list *true_rl;
2214 struct range_list *false_rl = NULL;
2215 sval_t right;
2216 sval_t zero = {
2217 .value = 0,
2218 };
2219
2220 if (!get_implied_value(expr->right, &right) || right.value == 0)
2221 return;
2222 get_absolute_rl(expr->left, &orig_rl);
2223
2224 zero.type = rl_type(orig_rl);
2225
2226 /* We're basically dorking around the min and max here */
2227 true_rl = remove_range(orig_rl, zero, zero);
2228 if (!sval_is_max(rl_max(true_rl)) &&
2229 !(rl_max(true_rl).value % right.value))
2230 true_rl = remove_range(true_rl, rl_max(true_rl), rl_max(true_rl));
2231
2232 if (rl_equiv(true_rl, orig_rl))
2233 true_rl = NULL;
2234
2235 if (sval_is_positive(rl_min(orig_rl)) &&
2236 (rl_max(orig_rl).value - rl_min(orig_rl).value) / right.value < 5) {
2237 sval_t add;
2238 int i;
2239
2240 add = rl_min(orig_rl);
2241 add.value += right.value - (add.value % right.value);
2242 add.value -= right.value;
2243
2244 for (i = 0; i < 5; i++) {
2245 add.value += right.value;
2246 if (add.value > rl_max(orig_rl).value)
2247 break;
2248 add_range(&false_rl, add, add);
2249 }
2250 } else {
2251 if (rl_min(orig_rl).uvalue != 0 &&
2252 rl_min(orig_rl).uvalue < right.uvalue) {
2253 sval_t chop = right;
2254 chop.value--;
2255 false_rl = remove_range(orig_rl, zero, chop);
2256 }
2257
2258 if (!sval_is_max(rl_max(orig_rl)) &&
2259 (rl_max(orig_rl).value % right.value)) {
2260 sval_t chop = rl_max(orig_rl);
2261 chop.value -= chop.value % right.value;
2262 chop.value++;
2263 if (!false_rl)
2264 false_rl = clone_rl(orig_rl);
2265 false_rl = remove_range(false_rl, chop, rl_max(orig_rl));
2266 }
2267 }
2268
2269 set_extra_expr_true_false(expr->left,
2270 true_rl ? alloc_estate_rl(true_rl) : NULL,
2271 false_rl ? alloc_estate_rl(false_rl) : NULL);
2272 }
2273
2274 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
2275 void __extra_match_condition(struct expression *expr)
2276 {
2277 expr = strip_expr(expr);
2278 switch (expr->type) {
2279 case EXPR_CALL:
2280 function_comparison(expr, SPECIAL_NOTEQUAL, zero_expr());
2281 return;
2282 case EXPR_PREOP:
2283 case EXPR_SYMBOL:
2284 case EXPR_DEREF:
2285 handle_comparison(get_type(expr), expr, SPECIAL_NOTEQUAL, zero_expr());
2286 return;
2287 case EXPR_COMPARE:
2288 match_comparison(expr);
2289 return;
2290 case EXPR_ASSIGNMENT:
2291 __extra_match_condition(expr->left);
2292 return;
2293 case EXPR_BINOP:
2294 if (expr->op == '&')
2295 handle_AND_condition(expr);
2296 if (expr->op == '%')
2297 handle_MOD_condition(expr);
2298 return;
2299 }
2300 }
2301
2302 static void assume_indexes_are_valid(struct expression *expr)
2303 {
2304 struct expression *array_expr;
2305 int array_size;
2306 struct expression *offset;
2307 struct symbol *offset_type;
2308 struct range_list *rl_before;
2309 struct range_list *rl_after;
2310 struct range_list *filter = NULL;
2311 sval_t size;
2312
2313 expr = strip_expr(expr);
2314 if (!is_array(expr))
2315 return;
2316
2317 offset = get_array_offset(expr);
2318 offset_type = get_type(offset);
2319 if (offset_type && type_signed(offset_type)) {
2320 filter = alloc_rl(sval_type_min(offset_type),
2321 sval_type_val(offset_type, -1));
2322 }
2323
2324 array_expr = get_array_base(expr);
2325 array_size = get_real_array_size(array_expr);
2326 if (array_size > 1) {
2327 size = sval_type_val(offset_type, array_size);
2328 add_range(&filter, size, sval_type_max(offset_type));
2329 }
2330
2331 if (!filter)
2332 return;
2333 get_absolute_rl(offset, &rl_before);
2334 rl_after = rl_filter(rl_before, filter);
2335 if (rl_equiv(rl_before, rl_after))
2336 return;
2337 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
2338 }
2339
2340 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
2341 int implied_not_equal(struct expression *expr, long long val)
2342 {
2343 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
2344 }
2345
2346 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
2347 {
2348 struct smatch_state *estate;
2349
2350 estate = get_state(SMATCH_EXTRA, name, sym);
2351 if (!estate)
2352 return 0;
2353 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
2354 return 1;
2355 return 0;
2356 }
2357
2358 bool is_noderef_ptr(struct expression *expr)
2359 {
2360 struct range_list *rl;
2361
2362 if (!get_implied_rl(expr, &rl))
2363 return false;
2364 return is_noderef_ptr_rl(rl);
2365 }
2366
2367 static int parent_is_err_or_null_var_sym_helper(const char *name, struct symbol *sym, bool check_err_ptr)
2368 {
2369 struct smatch_state *state;
2370 char buf[256];
2371 char *start;
2372 int len;
2373
2374 strncpy(buf, name, sizeof(buf) - 1);
2375 buf[sizeof(buf) - 1] = '\0';
2376
2377 start = &buf[0];
2378 while (*start == '*') {
2379 start++;
2380 state = __get_state(SMATCH_EXTRA, start, sym);
2381 if (!state)
2382 continue;
2383 if (!estate_rl(state))
2384 return 1;
2385 if (is_noderef_ptr_rl(estate_rl(state)))
2386 return 1;
2387 }
2388
2389 start = &buf[0];
2390 while (*start == '&')
2391 start++;
2392
2393 len = strlen(start);
2394 while (true) {
2395 while (len > 0) {
2396 len--;
2397 if (start[len] == '-' ||
2398 start[len] == '.') {
2399 start[len] = '\0';
2400 break;
2401 }
2402 }
2403 if (len == 0)
2404 return 0;
2405 state = __get_state(SMATCH_EXTRA, start, sym);
2406 if (!state)
2407 continue;
2408 if (is_noderef_ptr_rl(estate_rl(state)))
2409 return 1;
2410 }
2411 }
2412
2413 int parent_is_null_var_sym(const char *name, struct symbol *sym)
2414 {
2415 return parent_is_err_or_null_var_sym_helper(name, sym, false);
2416 }
2417
2418 int parent_is_err_or_null_var_sym(const char *name, struct symbol *sym)
2419 {
2420 return parent_is_err_or_null_var_sym_helper(name, sym, (option_project == PROJ_KERNEL));
2421 }
2422
2423 int parent_is_null(struct expression *expr)
2424 {
2425 struct symbol *sym;
2426 char *var;
2427 int ret = 0;
2428
2429 expr = strip_expr(expr);
2430 var = expr_to_var_sym(expr, &sym);
2431 if (!var || !sym)
2432 goto free;
2433 ret = parent_is_null_var_sym(var, sym);
2434 free:
2435 free_string(var);
2436 return ret;
2437 }
2438
2439 static int param_used_callback(void *found, int argc, char **argv, char **azColName)
2440 {
2441 *(int *)found = 1;
2442 return 0;
2443 }
2444
2445 static int is_kzalloc_info(struct sm_state *sm)
2446 {
2447 sval_t sval;
2448
2449 /*
2450 * kzalloc() information is treated as special because so there is just
2451 * a lot of stuff initialized to zero and it makes building the database
2452 * take hours and hours.
2453 *
2454 * In theory, we should just remove this line and not pass any unused
2455 * information, but I'm not sure enough that this code works so I want
2456 * to hold off on that for now.
2457 */
2458 if (!estate_get_single_value(sm->state, &sval))
2459 return 0;
2460 if (sval.value != 0)
2461 return 0;
2462 return 1;
2463 }
2464
2465 static int is_really_long(struct sm_state *sm)
2466 {
2467 const char *p;
2468 int cnt = 0;
2469
2470 p = sm->name;
2471 while ((p = strstr(p, "->"))) {
2472 p += 2;
2473 cnt++;
2474 }
2475
2476 if (cnt < 3 ||
2477 strlen(sm->name) < 40)
2478 return 0;
2479 return 1;
2480 }
2481
2482 static int filter_unused_param_value_info(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2483 {
2484 int found = 0;
2485
2486 /* for function pointers assume everything is used */
2487 if (call->fn->type != EXPR_SYMBOL)
2488 return 0;
2489
2490 if (strcmp(printed_name, "$") == 0 ||
2491 strcmp(printed_name, "*$") == 0)
2492 return 0;
2493
2494 /*
2495 * This is to handle __builtin_mul_overflow(). In an ideal world we
2496 * would only need this for invalid code.
2497 *
2498 */
2499 if (!call->fn->symbol)
2500 return 0;
2501
2502 if (!is_kzalloc_info(sm) && !is_really_long(sm))
2503 return 0;
2504
2505 run_sql(&param_used_callback, &found,
2506 "select * from return_implies where %s and type = %d and parameter = %d and key = '%s';",
2507 get_static_filter(call->fn->symbol), PARAM_USED, param, printed_name);
2508 if (found)
2509 return 0;
2510
2511 /* If the database is not built yet, then assume everything is used */
2512 run_sql(&param_used_callback, &found,
2513 "select * from return_implies where %s and type = %d;",
2514 get_static_filter(call->fn->symbol), PARAM_USED);
2515 if (!found)
2516 return 0;
2517
2518 return 1;
2519 }
2520
2521 struct range_list *intersect_with_real_abs_var_sym(const char *name, struct symbol *sym, struct range_list *start)
2522 {
2523 struct smatch_state *state;
2524
2525 /*
2526 * Here is the difference between implied value and real absolute, say
2527 * you have:
2528 *
2529 * int a = (u8)x;
2530 *
2531 * Then you know that a is 0-255. That's real absolute. But you don't
2532 * know for sure that it actually goes up to 255. So it's not implied.
2533 * Implied indicates a degree of certainty.
2534 *
2535 * But then say you cap "a" at 8. That means you know it goes up to
2536 * 8. So now the implied value is s32min-8. But you can combine it
2537 * with the real absolute to say that actually it's 0-8.
2538 *
2539 * We are combining it here. But now that I think about it, this is
2540 * probably not the ideal place to combine it because it should proably
2541 * be done earlier. Oh well, this is an improvement on what was there
2542 * before so I'm going to commit this code.
2543 *
2544 */
2545
2546 state = get_real_absolute_state_var_sym(name, sym);
2547 if (!state || !estate_rl(state))
2548 return start;
2549
2550 return rl_intersection(estate_rl(state), start);
2551 }
2552
2553 struct range_list *intersect_with_real_abs_expr(struct expression *expr, struct range_list *start)
2554 {
2555 struct smatch_state *state;
2556 struct range_list *abs_rl;
2557
2558 state = get_real_absolute_state(expr);
2559 if (!state || !estate_rl(state))
2560 return start;
2561
2562 abs_rl = cast_rl(rl_type(start), estate_rl(state));
2563 return rl_intersection(abs_rl, start);
2564 }
2565
2566 static void caller_info_callback(struct expression *call, int param, char *printed_name, struct sm_state *sm)
2567 {
2568 struct range_list *rl;
2569 sval_t dummy;
2570
2571 if (printed_name[0] == '&')
2572 return;
2573 if (estate_is_whole(sm->state) || !estate_rl(sm->state))
2574 return;
2575 if (filter_unused_param_value_info(call, param, printed_name, sm))
2576 return;
2577 rl = estate_rl(sm->state);
2578 rl = intersect_with_real_abs_var_sym(sm->name, sm->sym, rl);
2579 if (!rl)
2580 return;
2581 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, show_rl(rl));
2582 if (!estate_get_single_value(sm->state, &dummy)) {
2583 if (estate_has_hard_max(sm->state))
2584 sql_insert_caller_info(call, HARD_MAX, param, printed_name,
2585 sval_to_str(estate_max(sm->state)));
2586 if (estate_has_fuzzy_max(sm->state))
2587 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
2588 sval_to_str(estate_get_fuzzy_max(sm->state)));
2589 }
2590 }
2591
2592 static void returned_struct_members(int return_id, char *return_ranges, struct expression *expr)
2593 {
2594 struct symbol *returned_sym;
2595 char *returned_name;
2596 struct sm_state *sm;
2597 char *compare_str;
2598 char name_buf[256];
2599 char val_buf[256];
2600 int len;
2601
2602 // FIXME handle *$
2603
2604 if (!is_pointer(expr))
2605 return;
2606 if (return_ranges && strstr(return_ranges, "[==$"))
2607 return;
2608
2609 returned_name = expr_to_var_sym(expr, &returned_sym);
2610 if (!returned_name || !returned_sym)
2611 goto free;
2612 len = strlen(returned_name);
2613
2614 FOR_EACH_MY_SM(my_id, __get_cur_stree(), sm) {
2615 if (!estate_rl(sm->state))
2616 continue;
2617 if (returned_sym != sm->sym)
2618 continue;
2619 if (strncmp(returned_name, sm->name, len) != 0)
2620 continue;
2621 if (sm->name[len] != '-')
2622 continue;
2623
2624 snprintf(name_buf, sizeof(name_buf), "$%s", sm->name + len);
2625
2626 compare_str = name_sym_to_param_comparison(sm->name, sm->sym);
2627 if (!compare_str && estate_is_whole(sm->state))
2628 continue;
2629 snprintf(val_buf, sizeof(val_buf), "%s%s", sm->state->name, compare_str ?: "");
2630
2631 sql_insert_return_states(return_id, return_ranges, PARAM_VALUE,
2632 -1, name_buf, val_buf);
2633 } END_FOR_EACH_SM(sm);
2634
2635 free:
2636 free_string(returned_name);
2637 }
2638
2639 static void db_limited_before(void)
2640 {
2641 unmatched_stree = clone_stree(__get_cur_stree());
2642 }
2643
2644 static void db_limited_after(void)
2645 {
2646 free_stree(&unmatched_stree);
2647 }
2648
2649 static int basically_the_same(struct range_list *orig, struct range_list *new)
2650 {
2651 if (type_is_ptr(rl_type(orig)) &&
2652 is_whole_ptr_rl(orig) &&
2653 is_whole_ptr_rl(new))
2654 return true;
2655
2656 return rl_equiv(orig, new);
2657 }
2658
2659 static void db_param_limit_binops(struct expression *arg, char *key, struct range_list *rl)
2660 {
2661 struct range_list *left_rl;
2662 sval_t zero = { .type = rl_type(rl), };
2663 sval_t sval;
2664
2665 if (strcmp(key, "$") != 0)
2666 return;
2667 if (arg->op != '*')
2668 return;
2669 if (!get_implied_value(arg->right, &sval))
2670 return;
2671 if (can_integer_overflow(get_type(arg), arg))
2672 return;
2673
2674 left_rl = rl_binop(rl, '/', alloc_rl(sval, sval));
2675 if (!rl_has_sval(rl, zero))
2676 left_rl = remove_range(left_rl, zero, zero);
2677
2678 set_extra_expr_nomod(arg->left, alloc_estate_rl(left_rl));
2679 }
2680
2681 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, enum info_type op)
2682 {
2683 struct smatch_state *state;
2684 struct expression *arg;
2685 char *name;
2686 struct symbol *sym;
2687 struct var_sym_list *vsl = NULL;
2688 struct sm_state *sm;
2689 struct symbol *compare_type, *var_type;
2690 struct range_list *rl;
2691 struct range_list *limit;
2692 struct range_list *new;
2693 char *other_name;
2694 struct symbol *other_sym;
2695
2696 while (expr->type == EXPR_ASSIGNMENT)
2697 expr = strip_expr(expr->right);
2698 if (expr->type != EXPR_CALL)
2699 return;
2700
2701 arg = get_argument_from_call_expr(expr->args, param);
2702 if (!arg)
2703 return;
2704
2705 if (strcmp(key, "$") == 0)
2706 compare_type = get_arg_type(expr->fn, param);
2707 else
2708 compare_type = get_member_type_from_key(arg, key);
2709
2710 call_results_to_rl(expr, compare_type, value, &limit);
2711 if (strcmp(key, "$") == 0)
2712 move_known_to_rl(&arg, &limit);
2713 name = get_chunk_from_key(arg, key, &sym, &vsl);
2714 if (!name)
2715 return;
2716 if (op != PARAM_LIMIT && !sym)
2717 goto free;
2718
2719 sm = get_sm_state(SMATCH_EXTRA, name, sym);
2720 if (sm)
2721 rl = estate_rl(sm->state);
2722 else
2723 rl = alloc_whole_rl(compare_type);
2724
2725 if (op == PARAM_LIMIT && !rl_fits_in_type(rl, compare_type))
2726 goto free;
2727
2728 new = rl_intersection(rl, limit);
2729
2730 var_type = get_member_type_from_key(arg, key);
2731 new = cast_rl(var_type, new);
2732
2733 /* We want to preserve the implications here */
2734 if (sm && basically_the_same(rl, new))
2735 goto free;
2736 other_name = get_other_name_sym(name, sym, &other_sym);
2737
2738 state = alloc_estate_rl(new);
2739 if (sm && estate_has_hard_max(sm->state))
2740 estate_set_hard_max(state);
2741
2742 if (op == PARAM_LIMIT) {
2743 set_extra_nomod_vsl(name, sym, vsl, NULL, state);
2744 } else
2745 set_extra_mod(name, sym, NULL, state);
2746
2747 if (other_name && other_sym) {
2748 state = clone_estate(state);
2749 if (op == PARAM_LIMIT)
2750 set_extra_nomod_vsl(other_name, other_sym, vsl, NULL, state);
2751 else
2752 set_extra_mod(other_name, other_sym, NULL, state);
2753 }
2754
2755 if (op == PARAM_LIMIT && arg->type == EXPR_BINOP)
2756 db_param_limit_binops(arg, key, new);
2757 free:
2758 free_string(name);
2759 }
2760
2761 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
2762 {
2763 db_param_limit_filter(expr, param, key, value, PARAM_LIMIT);
2764 }
2765
2766 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
2767 {
2768 db_param_limit_filter(expr, param, key, value, PARAM_FILTER);
2769 }
2770
2771 static struct expression *get_star_pointer_hack(struct expression *arg, const char *key)
2772 {
2773 /* if we are setting *(p + offset) then we are setting *p */
2774 if (strcmp(key, "*$") != 0)
2775 return NULL;
2776
2777 arg = strip_expr(arg);
2778 if (arg->op != '+')
2779 return NULL;
2780 arg = strip_expr(arg->left);
2781 if (!is_pointer(arg))
2782 return NULL;
2783 return arg;
2784 }
2785
2786 static void db_param_add_set(struct expression *expr, int param, char *key, char *value, enum info_type op)
2787 {
2788 struct expression *arg, *gen_expr;
2789 char *name;
2790 char *other_name = NULL;
2791 struct symbol *sym, *other_sym;
2792 struct symbol *param_type, *arg_type;
2793 struct smatch_state *state;
2794 struct range_list *new = NULL;
2795 struct range_list *added = NULL;
2796
2797 while (expr->type == EXPR_ASSIGNMENT)
2798 expr = strip_expr(expr->right);
2799 if (expr->type != EXPR_CALL)
2800 return;
2801
2802 arg = get_argument_from_call_expr(expr->args, param);
2803 if (!arg)
2804 return;
2805
2806 arg_type = get_arg_type_from_key(expr->fn, param, arg, key);
2807 param_type = get_member_type_from_key(arg, key);
2808 if (param_type && param_type->type == SYM_STRUCT)
2809 return;
2810 name = get_variable_from_key(arg, key, &sym);
2811 if (!name || !sym) {
2812 arg = get_star_pointer_hack(arg, key);
2813 if (!arg)
2814 goto free;
2815 name = get_variable_from_key(arg, key, &sym);
2816 if (!name || !sym)
2817 goto free;
2818 }
2819 gen_expr = gen_expression_from_key(arg, key);
2820
2821 state = get_state(SMATCH_EXTRA, name, sym);
2822 if (state)
2823 new = estate_rl(state);
2824
2825 call_results_to_rl(expr, arg_type, value, &added);
2826 added = cast_rl(param_type, added);
2827 if (op == PARAM_SET)
2828 new = added;
2829 else
2830 new = rl_union(new, added);
2831
2832 other_name = get_other_name_sym_nostack(name, sym, &other_sym);
2833 set_extra_mod(name, sym, gen_expr, alloc_estate_rl(new));
2834 if (other_name && other_sym)
2835 set_extra_mod(other_name, other_sym, gen_expr, alloc_estate_rl(new));
2836 free:
2837 free_string(other_name);
2838 free_string(name);
2839 }
2840
2841 static void db_param_add(struct expression *expr, int param, char *key, char *value)
2842 {
2843 in_param_set = true;
2844 db_param_add_set(expr, param, key, value, PARAM_ADD);
2845 in_param_set = false;
2846 }
2847
2848 static void db_param_set(struct expression *expr, int param, char *key, char *value)
2849 {
2850 in_param_set = true;
2851 db_param_add_set(expr, param, key, value, PARAM_SET);
2852 in_param_set = false;
2853 }
2854
2855 static void match_lost_param(struct expression *call, int param)
2856 {
2857 struct expression *arg;
2858
2859 if (is_const_param(call->fn, param))
2860 return;
2861
2862 arg = get_argument_from_call_expr(call->args, param);
2863 if (!arg)
2864 return;
2865
2866 arg = strip_expr(arg);
2867 if (arg->type == EXPR_PREOP && arg->op == '&')
2868 set_extra_expr_mod(arg->unop, alloc_estate_whole(get_type(arg->unop)));
2869 else
2870 ; /* if pointer then set struct members, maybe?*/
2871 }
2872
2873 static void db_param_value(struct expression *expr, int param, char *key, char *value)
2874 {
2875 struct expression *call;
2876 char *name;
2877 struct symbol *sym;
2878 struct symbol *type;
2879 struct range_list *rl = NULL;
2880
2881 if (param != -1)
2882 return;
2883
2884 call = expr;
2885 while (call->type == EXPR_ASSIGNMENT)
2886 call = strip_expr(call->right);
2887 if (call->type != EXPR_CALL)
2888 return;
2889
2890 type = get_member_type_from_key(expr->left, key);
2891 name = get_variable_from_key(expr->left, key, &sym);
2892 if (!name || !sym)
2893 goto free;
2894
2895 call_results_to_rl(call, type, value, &rl);
2896
2897 set_extra_mod(name, sym, NULL, alloc_estate_rl(rl));
2898 free:
2899 free_string(name);
2900 }
2901
2902 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
2903 {
2904 struct expression *expr;
2905 struct range_list *rl = NULL;
2906 struct smatch_state *state;
2907 struct symbol *type;
2908 char *key_orig = key;
2909 char *fullname;
2910 sval_t dummy;
2911
2912 expr = symbol_expression(sym);
2913 fullname = get_variable_from_key(expr, key, NULL);
2914 if (!fullname)
2915 return;
2916
2917 type = get_member_type_from_key(expr, key_orig);
2918 str_to_rl(type, value, &rl);
2919 state = alloc_estate_rl(rl);
2920 if (estate_get_single_value(state, &dummy))
2921 estate_set_hard_max(state);
2922 set_state(SMATCH_EXTRA, fullname, sym, state);
2923 }
2924
2925 static void db_buf_add_helper(struct expression *expr, void *data)
2926 {
2927 struct expression *left = expr->left;
2928 struct sm_state *sm;
2929
2930 sm = get_sm_state_expr(my_id, left);
2931 if (!sm)
2932 return;
2933
2934 set_state(my_id, sm->name, sm->sym, alloc_estate_whole(estate_type(sm->state)));
2935 }
2936
2937 static void db_buf_add(struct expression *expr, int param, char *key, char *value)
2938 {
2939 struct expression *arg;
2940
2941 /*
2942 * There really isn't much we can do with a BUF_ADD. A BUF_CLEAR is
2943 * like a full modification which some stuff cares about. A no_mod
2944 * thing is useful because that's normally bounds checking etc. But
2945 * with BUF_ADD the only thing we can say is do is delete any previous
2946 * known states.
2947 *
2948 */
2949
2950 arg = gen_expr_from_param_key(expr, param, key);
2951 if (!arg)
2952 return;
2953
2954 create_recursive_fake_assignments(deref_expression(arg), &db_buf_add_helper, NULL);
2955 }
2956
2957 static void set_param_fuzzy_max(const char *name, struct symbol *sym, char *key, char *value)
2958 {
2959 struct expression *expr;
2960 struct range_list *rl = NULL;
2961 struct smatch_state *state;
2962 struct symbol *type;
2963 char *fullname;
2964 sval_t max;
2965
2966 expr = symbol_expression(sym);
2967 fullname = get_variable_from_key(expr, key, NULL);
2968 if (!fullname)
2969 return;
2970
2971 state = get_state(SMATCH_EXTRA, fullname, sym);
2972 if (!state)
2973 return;
2974 type = estate_type(state);
2975 str_to_rl(type, value, &rl);
2976 if (!rl_to_sval(rl, &max))
2977 return;
2978 estate_set_fuzzy_max(state, max);
2979 }
2980
2981 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
2982 {
2983 struct smatch_state *state;
2984 struct expression *expr;
2985 char *fullname;
2986
2987 expr = symbol_expression(sym);
2988 fullname = get_variable_from_key(expr, key, NULL);
2989 if (!fullname)
2990 return;
2991
2992 state = get_state(SMATCH_EXTRA, fullname, sym);
2993 if (!state)
2994 return;
2995 estate_set_hard_max(state);
2996 }
2997
2998 static struct sm_state *get_sm_from_call(struct expression *expr)
2999 {
3000 struct expression *fake;
3001 struct sm_state *ret;
3002 char buf[32];
3003
3004 if (is_fake_call(expr))
3005 return NULL;
3006
3007 fake = expr_get_fake_parent_expr(expr);
3008 if (fake && fake->type == EXPR_ASSIGNMENT) {
3009 ret = get_sm_state_expr(SMATCH_EXTRA, fake->left);
3010 if (ret)
3011 return ret;
3012 }
3013
3014 snprintf(buf, sizeof(buf), "return %p", expr);
3015 return get_sm_state(SMATCH_EXTRA, buf, NULL);
3016 }
3017
3018 struct sm_state *get_extra_sm_state(struct expression *expr)
3019 {
3020 char *name;
3021 struct symbol *sym;
3022 struct sm_state *ret = NULL;
3023
3024 expr = strip_expr(expr);
3025 if (!expr)
3026 return NULL;
3027
3028 if (expr->type == EXPR_CALL)
3029 return get_sm_from_call(expr);
3030
3031 name = expr_to_known_chunk_sym(expr, &sym);
3032 if (!name)
3033 goto free;
3034
3035 ret = get_sm_state(SMATCH_EXTRA, name, sym);
3036 free:
3037 free_string(name);
3038 return ret;
3039 }
3040
3041 struct smatch_state *get_extra_state(struct expression *expr)
3042 {
3043 struct sm_state *sm;
3044
3045 sm = get_extra_sm_state(expr);
3046 if (!sm)
3047 return NULL;
3048 return sm->state;
3049 }
3050
3051 void register_smatch_extra(int id)
3052 {
3053 my_id = id;
3054
3055 set_dynamic_states(my_id);
3056 add_merge_hook(my_id, &merge_estates);
3057 add_unmatched_state_hook(my_id, &unmatched_state);
3058 select_caller_info_hook(set_param_value, PARAM_VALUE);
3059 select_caller_info_hook(set_param_fuzzy_max, FUZZY_MAX);
3060 select_caller_info_hook(set_param_hard_max, HARD_MAX);
3061 select_return_states_before(&db_limited_before);
3062 select_return_states_hook(PARAM_LIMIT, &db_param_limit);
3063 select_return_states_hook(PARAM_FILTER, &db_param_filter);
3064 select_return_states_hook(PARAM_ADD, &db_param_add);
3065 select_return_states_hook(PARAM_SET, &db_param_set);
3066 select_return_states_hook(BUF_ADD, &db_buf_add);
3067 add_lost_param_hook(&match_lost_param);
3068 select_return_states_hook(PARAM_VALUE, &db_param_value);
3069 select_return_states_after(&db_limited_after);
3070 }
3071
3072 static void match_link_modify(struct sm_state *sm, struct expression *mod_expr)
3073 {
3074 struct var_sym_list *links;
3075 struct var_sym *tmp;
3076 struct smatch_state *state;
3077
3078 links = sm->state->data;
3079
3080 FOR_EACH_PTR(links, tmp) {
3081 if (sm->sym == tmp->sym &&
3082 strcmp(sm->name, tmp->var) == 0)
3083 continue;
3084 state = get_state(SMATCH_EXTRA, tmp->var, tmp->sym);
3085 if (!state)
3086 continue;
3087 set_state(SMATCH_EXTRA, tmp->var, tmp->sym, alloc_estate_whole(estate_type(state)));
3088 } END_FOR_EACH_PTR(tmp);
3089 set_state(link_id, sm->name, sm->sym, &undefined);
3090 }
3091
3092 void register_smatch_extra_links(int id)
3093 {
3094 link_id = id;
3095 set_dynamic_states(link_id);
3096 }
3097
3098 void register_smatch_extra_late(int id)
3099 {
3100 add_merge_hook(link_id, &merge_link_states);
3101 add_modification_hook(link_id, &match_link_modify);
3102 add_hook(&match_dereferences, DEREF_HOOK);
3103 add_hook(&match_pointer_as_array, OP_HOOK);
3104 select_return_implies_hook_early(DEREFERENCE, &set_param_dereferenced);
3105 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
3106 add_hook(&match_assign, ASSIGNMENT_HOOK);
3107 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
3108 add_hook(&unop_expr, OP_HOOK);
3109 add_hook(&asm_expr, ASM_HOOK);
3110
3111 add_caller_info_callback(my_id, caller_info_callback);
3112 add_split_return_callback(&returned_struct_members);
3113
3114 // add_hook(&assume_indexes_are_valid, OP_HOOK);
3115 }