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free: improve cross function tracking
[smatch.git] / smatch_extra.c
blob5382fd766b321db895ce042329543f7151729b70
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 #include <stdlib.h>
24 #include <errno.h>
25 #ifndef __USE_ISOC99
26 #define __USE_ISOC99
27 #endif
28 #include <limits.h>
29 #include "parse.h"
30 #include "smatch.h"
31 #include "smatch_slist.h"
32 #include "smatch_extra.h"
33
34 static int my_id;
35
36 struct string_list *__ignored_macros = NULL;
37 static int in_warn_on_macro(void)
38 {
39 struct statement *stmt;
40 char *tmp;
41 char *macro;
42
43 stmt = get_current_statement();
44 if (!stmt)
45 return 0;
46 macro = get_macro_name(stmt->pos);
47 if (!macro)
48 return 0;
49
50 FOR_EACH_PTR(__ignored_macros, tmp) {
51 if (!strcmp(tmp, macro))
52 return 1;
53 } END_FOR_EACH_PTR(tmp);
54 return 0;
55 }
56
57 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
58 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
59 static struct void_fn_list *extra_mod_hooks;
60 void add_extra_mod_hook(mod_hook *fn)
61 {
62 mod_hook **p = malloc(sizeof(mod_hook *));
63 *p = fn;
64 add_ptr_list(&extra_mod_hooks, p);
65 }
66
67 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
68 {
69 mod_hook **fn;
70
71 FOR_EACH_PTR(extra_mod_hooks, fn) {
72 (*fn)(name, sym, state);
73 } END_FOR_EACH_PTR(fn);
74 }
75
76 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
77 {
78 if (in_warn_on_macro())
79 return NULL;
80 remove_from_equiv(name, sym);
81 call_extra_mod_hooks(name, sym, state);
82 return set_state(SMATCH_EXTRA, name, sym, state);
83 }
84
85 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
86 {
87 struct symbol *sym;
88 char *name;
89 struct sm_state *ret = NULL;
90
91 expr = strip_expr(expr);
92 name = expr_to_var_sym(expr, &sym);
93 if (!name || !sym)
94 goto free;
95 ret = set_extra_mod(name, sym, state);
96 free:
97 free_string(name);
98 return ret;
99 }
100
101 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
102 {
103 struct relation *rel;
104 struct smatch_state *orig_state;
105
106 orig_state = get_state(SMATCH_EXTRA, name, sym);
107
108 if (!estate_related(orig_state)) {
109 set_state(SMATCH_EXTRA, name, sym, state);
110 return;
111 }
112
113 set_related(state, estate_related(orig_state));
114 FOR_EACH_PTR(estate_related(orig_state), rel) {
115 if (option_debug_related)
116 sm_msg("%s updating related %s to %s", name, rel->name, state->name);
117 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
118 } END_FOR_EACH_PTR(rel);
119 }
120
121 /*
122 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
123 */
124 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
125 {
126 char *name;
127 struct symbol *sym;
128
129 name = expr_to_var_sym(expr, &sym);
130 if (!name || !sym)
131 goto free;
132 set_extra_nomod(name, sym, state);
133 free:
134 free_string(name);
135
136 }
137
138 static void set_extra_true_false(const char *name, struct symbol *sym,
139 struct smatch_state *true_state,
140 struct smatch_state *false_state)
141 {
142 struct relation *rel;
143 struct smatch_state *orig_state;
144
145 if (in_warn_on_macro())
146 return;
147
148 orig_state = get_state(SMATCH_EXTRA, name, sym);
149
150 if (!estate_related(orig_state)) {
151 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
152 return;
153 }
154
155 if (true_state)
156 set_related(true_state, estate_related(orig_state));
157 if (false_state)
158 set_related(false_state, estate_related(orig_state));
159
160 FOR_EACH_PTR(estate_related(orig_state), rel) {
161 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
162 true_state, false_state);
163 } END_FOR_EACH_PTR(rel);
164 }
165
166 static void set_extra_expr_true_false(struct expression *expr,
167 struct smatch_state *true_state,
168 struct smatch_state *false_state)
169 {
170 char *name;
171 struct symbol *sym;
172
173 expr = strip_expr(expr);
174 name = expr_to_var_sym(expr, &sym);
175 if (!name || !sym)
176 goto free;
177 set_extra_true_false(name, sym, true_state, false_state);
178 free:
179 free_string(name);
180 }
181
182 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
183 {
184 struct expression *iter_var;
185 struct expression *condition;
186 struct sm_state *sm;
187 struct smatch_state *estate;
188 sval_t start;
189
190 condition = strip_expr(loop->iterator_pre_condition);
191 if (!condition)
192 return NULL;
193 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
194 return NULL;
195 if (condition->op != SPECIAL_DECREMENT)
196 return NULL;
197
198 iter_var = condition->unop;
199 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
200 if (!sm)
201 return NULL;
202 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
203 return NULL;
204 start = estate_max(sm->state);
205 if (sval_cmp_val(start, 0) <= 0)
206 return NULL;
207 if (!sval_is_max(start))
208 start.value--;
209
210 if (condition->type == EXPR_PREOP) {
211 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
212 if (estate_has_hard_max(sm->state))
213 estate_set_hard_max(estate);
214 estate_copy_fuzzy_max(estate, sm->state);
215 set_extra_expr_mod(iter_var, estate);
216 }
217 if (condition->type == EXPR_POSTOP) {
218 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
219 if (estate_has_hard_max(sm->state))
220 estate_set_hard_max(estate);
221 estate_copy_fuzzy_max(estate, sm->state);
222 set_extra_expr_mod(iter_var, estate);
223 }
224 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
225 }
226
227 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
228 struct expression *condition)
229 {
230 struct expression *iter_var;
231 struct sm_state *sm;
232 struct smatch_state *estate;
233 sval_t start, end, max;
234
235 iter_var = iter_expr->unop;
236 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
237 if (!sm)
238 return NULL;
239 if (!estate_get_single_value(sm->state, &start))
240 return NULL;
241 if (get_implied_max(condition->right, &end))
242 end = sval_cast(get_type(iter_var), end);
243 else
244 end = sval_type_max(get_type(iter_var));
245
246 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
247 return NULL;
248
249 switch (condition->op) {
250 case SPECIAL_UNSIGNED_LT:
251 case SPECIAL_NOTEQUAL:
252 case '<':
253 if (!sval_is_min(end))
254 end.value--;
255 break;
256 case SPECIAL_UNSIGNED_LTE:
257 case SPECIAL_LTE:
258 break;
259 default:
260 return NULL;
261 }
262 if (sval_cmp(end, start) < 0)
263 return NULL;
264 estate = alloc_estate_range(start, end);
265 if (get_hard_max(condition->right, &max)) {
266 estate_set_hard_max(estate);
267 if (condition->op == '<' ||
268 condition->op == SPECIAL_UNSIGNED_LT ||
269 condition->op == SPECIAL_NOTEQUAL)
270 max.value--;
271 estate_set_fuzzy_max(estate, max);
272 }
273 set_extra_expr_mod(iter_var, estate);
274 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
275 }
276
277 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
278 struct expression *condition)
279 {
280 struct expression *iter_var;
281 struct sm_state *sm;
282 struct smatch_state *estate;
283 sval_t start, end;
284
285 iter_var = iter_expr->unop;
286 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
287 if (!sm)
288 return NULL;
289 if (!estate_get_single_value(sm->state, &start))
290 return NULL;
291 if (!get_implied_min(condition->right, &end))
292 end = sval_type_min(get_type(iter_var));
293 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
294 return NULL;
295
296 switch (condition->op) {
297 case SPECIAL_NOTEQUAL:
298 case '>':
299 if (!sval_is_min(end) && !sval_is_max(end))
300 end.value++;
301 break;
302 case SPECIAL_GTE:
303 break;
304 default:
305 return NULL;
306 }
307 if (sval_cmp(end, start) > 0)
308 return NULL;
309 estate = alloc_estate_range(end, start);
310 estate_set_hard_max(estate);
311 estate_set_fuzzy_max(estate, estate_get_fuzzy_max(estate));
312 set_extra_expr_mod(iter_var, estate);
313 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
314 }
315
316 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
317 {
318 struct expression *iter_expr;
319 struct expression *condition;
320
321 if (!loop->iterator_post_statement)
322 return NULL;
323 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
324 return NULL;
325 iter_expr = loop->iterator_post_statement->expression;
326 if (!loop->iterator_pre_condition)
327 return NULL;
328 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
329 return NULL;
330 condition = loop->iterator_pre_condition;
331
332 if (iter_expr->op == SPECIAL_INCREMENT)
333 return handle_canonical_for_inc(iter_expr, condition);
334 if (iter_expr->op == SPECIAL_DECREMENT)
335 return handle_canonical_for_dec(iter_expr, condition);
336 return NULL;
337 }
338
339 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct stree **stree)
340 {
341 struct sm_state *ret;
342
343 __push_fake_cur_stree();
344 if (!loop->iterator_post_statement)
345 ret = handle_canonical_while_count_down(loop);
346 else
347 ret = handle_canonical_for_loops(loop);
348 *stree = __pop_fake_cur_stree();
349 return ret;
350 }
351
352 int __iterator_unchanged(struct sm_state *sm)
353 {
354 if (!sm)
355 return 0;
356 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
357 return 1;
358 return 0;
359 }
360
361 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
362 {
363 sval_t after_value;
364
365 /* paranoid checking. prolly not needed */
366 condition = strip_expr(condition);
367 if (!condition)
368 return;
369 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
370 return;
371 if (condition->op != SPECIAL_DECREMENT)
372 return;
373 after_value = estate_min(sm->state);
374 after_value.value--;
375 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
376 }
377
378 void __extra_pre_loop_hook_after(struct sm_state *sm,
379 struct statement *iterator,
380 struct expression *condition)
381 {
382 struct expression *iter_expr;
383 sval_t limit;
384 struct smatch_state *state;
385
386 if (!iterator) {
387 while_count_down_after(sm, condition);
388 return;
389 }
390
391 iter_expr = iterator->expression;
392
393 if (condition->type != EXPR_COMPARE)
394 return;
395 if (iter_expr->op == SPECIAL_INCREMENT) {
396 limit = sval_binop(estate_max(sm->state), '+',
397 sval_type_val(estate_type(sm->state), 1));
398 } else {
399 limit = sval_binop(estate_min(sm->state), '-',
400 sval_type_val(estate_type(sm->state), 1));
401 }
402 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
403 if (iter_expr->op == SPECIAL_INCREMENT)
404 state = alloc_estate_range(estate_min(sm->state), limit);
405 else
406 state = alloc_estate_range(limit, estate_max(sm->state));
407 } else {
408 state = alloc_estate_sval(limit);
409 }
410 if (!estate_has_hard_max(sm->state)) {
411 estate_clear_hard_max(state);
412 }
413 if (estate_has_fuzzy_max(sm->state)) {
414 sval_t hmax = estate_get_fuzzy_max(sm->state);
415 sval_t max = estate_max(sm->state);
416
417 if (sval_cmp(hmax, max) != 0)
418 estate_clear_fuzzy_max(state);
419 } else if (!estate_has_fuzzy_max(sm->state)) {
420 estate_clear_fuzzy_max(state);
421 }
422
423 set_extra_mod(sm->name, sm->sym, state);
424 }
425
426 static struct stree *unmatched_stree;
427 static struct smatch_state *unmatched_state(struct sm_state *sm)
428 {
429 struct smatch_state *state;
430
431 if (unmatched_stree) {
432 state = get_state_stree(unmatched_stree, SMATCH_EXTRA, sm->name, sm->sym);
433 if (state)
434 return state;
435 }
436 if (parent_is_null_var_sym(sm->name, sm->sym))
437 return alloc_estate_empty();
438 return alloc_estate_whole(estate_type(sm->state));
439 }
440
441 static void clear_the_pointed_at(struct expression *expr)
442 {
443 struct stree *stree;
444 char *name;
445 struct symbol *sym;
446 struct sm_state *tmp;
447
448 name = expr_to_var_sym(expr, &sym);
449 if (!name || !sym)
450 goto free;
451
452 stree = __get_cur_stree();
453 FOR_EACH_MY_SM(SMATCH_EXTRA, stree, tmp) {
454 if (tmp->name[0] != '*')
455 continue;
456 if (tmp->sym != sym)
457 continue;
458 if (strcmp(tmp->name + 1, name) != 0)
459 continue;
460 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
461 } END_FOR_EACH_SM(tmp);
462
463 free:
464 free_string(name);
465 }
466
467 static void match_function_call(struct expression *expr)
468 {
469 struct expression *arg;
470 struct expression *tmp;
471
472 /* if we have the db this is handled in smatch_function_hooks.c */
473 if (!option_no_db)
474 return;
475 if (inlinable(expr->fn))
476 return;
477
478 FOR_EACH_PTR(expr->args, arg) {
479 tmp = strip_expr(arg);
480 if (tmp->type == EXPR_PREOP && tmp->op == '&')
481 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
482 else
483 clear_the_pointed_at(tmp);
484 } END_FOR_EACH_PTR(arg);
485 }
486
487 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
488 {
489 if (!one || !two)
490 return 0;
491 if (one->type == SYM_PTR && two->type == SYM_PTR)
492 return 1;
493 return types_equiv(one, two);
494 }
495
496 static bool is_non_null_array(struct expression *expr)
497 {
498 struct symbol *type;
499 struct symbol *sym;
500 struct symbol *tmp;
501 char *name;
502 int i;
503
504 type = get_type(expr);
505 if (!type || type->type != SYM_ARRAY)
506 return 0;
507 if (expr->type == EXPR_SYMBOL)
508 return 1;
509 if (implied_not_equal(expr, 0))
510 return 1;
511
512 /* verify that it's not the first member of the struct */
513 if (expr->type != EXPR_DEREF || !expr->member)
514 return 0;
515 name = expr_to_var_sym(expr, &sym);
516 free_string(name);
517 if (!name || !sym)
518 return 0;
519 type = get_real_base_type(sym);
520 if (!type || type->type != SYM_PTR)
521 return 0;
522 type = get_real_base_type(type);
523 if (type->type != SYM_STRUCT)
524 return 0;
525
526 i = 0;
527 FOR_EACH_PTR(type->symbol_list, tmp) {
528 i++;
529 if (!tmp->ident)
530 continue;
531 if (strcmp(expr->member->name, tmp->ident->name) == 0) {
532 if (i == 1)
533 return 0;
534 return 1;
535 }
536 } END_FOR_EACH_PTR(tmp);
537
538 return 0;
539 }
540
541 static void match_vanilla_assign(struct expression *left, struct expression *right)
542 {
543 struct range_list *rl = NULL;
544 struct symbol *right_sym;
545 struct symbol *left_type;
546 struct symbol *right_type;
547 char *right_name = NULL;
548 struct symbol *sym;
549 char *name;
550 sval_t max;
551 struct smatch_state *state;
552
553 if (is_struct(left))
554 return;
555
556 name = expr_to_var_sym(left, &sym);
557 if (!name)
558 return;
559
560 left_type = get_type(left);
561 right_type = get_type(right);
562
563 right_name = expr_to_var_sym(right, &right_sym);
564
565 if (!(right->type == EXPR_PREOP && right->op == '&') &&
566 right_name && right_sym &&
567 types_equiv_or_pointer(left_type, right_type) &&
568 !has_symbol(right, sym)) {
569 set_equiv(left, right);
570 goto free;
571 }
572
573 if (is_non_null_array(right)) {
574 state = alloc_estate_range(array_min_sval, array_max_sval);
575 } else if (get_implied_rl(right, &rl)) {
576 rl = cast_rl(left_type, rl);
577 state = alloc_estate_rl(rl);
578 if (get_hard_max(right, &max)) {
579 estate_set_hard_max(state);
580 estate_set_fuzzy_max(state, max);
581 }
582 } else {
583 rl = alloc_whole_rl(right_type);
584 rl = cast_rl(left_type, rl);
585 state = alloc_estate_rl(rl);
586 }
587 set_extra_mod(name, sym, state);
588 free:
589 free_string(right_name);
590 }
591
592 static int op_remove_assign(int op)
593 {
594 switch (op) {
595 case SPECIAL_ADD_ASSIGN:
596 return '+';
597 case SPECIAL_SUB_ASSIGN:
598 return '-';
599 case SPECIAL_MUL_ASSIGN:
600 return '*';
601 case SPECIAL_DIV_ASSIGN:
602 return '/';
603 case SPECIAL_MOD_ASSIGN:
604 return '%';
605 case SPECIAL_AND_ASSIGN:
606 return '&';
607 case SPECIAL_OR_ASSIGN:
608 return '|';
609 case SPECIAL_XOR_ASSIGN:
610 return '^';
611 case SPECIAL_SHL_ASSIGN:
612 return SPECIAL_LEFTSHIFT;
613 case SPECIAL_SHR_ASSIGN:
614 return SPECIAL_RIGHTSHIFT;
615 default:
616 return op;
617 }
618 }
619
620 static void match_assign(struct expression *expr)
621 {
622 struct range_list *rl = NULL;
623 struct expression *left;
624 struct expression *right;
625 struct expression *binop_expr;
626 struct symbol *left_type;
627 struct symbol *right_type;
628 struct symbol *sym;
629 char *name;
630 sval_t left_min, left_max;
631 sval_t right_min, right_max;
632 sval_t res_min, res_max;
633
634 left = strip_expr(expr->left);
635
636 right = strip_expr(expr->right);
637 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
638 right = strip_expr(right->left);
639
640 if (is_condition(expr->right))
641 return; /* handled in smatch_condition.c */
642 if (expr->op == '=' && right->type == EXPR_CALL)
643 return; /* handled in smatch_function_hooks.c */
644 if (expr->op == '=') {
645 match_vanilla_assign(left, right);
646 return;
647 }
648
649 name = expr_to_var_sym(left, &sym);
650 if (!name)
651 return;
652
653 left_type = get_type(left);
654 right_type = get_type(right);
655
656 res_min = sval_type_min(left_type);
657 res_max = sval_type_max(left_type);
658
659 switch (expr->op) {
660 case SPECIAL_ADD_ASSIGN:
661 get_absolute_max(left, &left_max);
662 get_absolute_max(right, &right_max);
663 if (sval_binop_overflows(left_max, '+', right_max))
664 break;
665 if (get_implied_min(left, &left_min) &&
666 !sval_is_negative_min(left_min) &&
667 get_implied_min(right, &right_min) &&
668 !sval_is_negative_min(right_min)) {
669 res_min = sval_binop(left_min, '+', right_min);
670 res_min = sval_cast(right_type, res_min);
671 }
672 if (inside_loop()) /* we are assuming loops don't lead to wrapping */
673 break;
674 res_max = sval_binop(left_max, '+', right_max);
675 res_max = sval_cast(right_type, res_max);
676 break;
677 case SPECIAL_SUB_ASSIGN:
678 if (get_implied_max(left, &left_max) &&
679 !sval_is_max(left_max) &&
680 get_implied_min(right, &right_min) &&
681 !sval_is_min(right_min)) {
682 res_max = sval_binop(left_max, '-', right_min);
683 res_max = sval_cast(right_type, res_max);
684 }
685 if (inside_loop())
686 break;
687 if (get_implied_min(left, &left_min) &&
688 !sval_is_min(left_min) &&
689 get_implied_max(right, &right_max) &&
690 !sval_is_max(right_max)) {
691 res_min = sval_binop(left_min, '-', right_max);
692 res_min = sval_cast(right_type, res_min);
693 }
694 break;
695 case SPECIAL_AND_ASSIGN:
696 case SPECIAL_MOD_ASSIGN:
697 case SPECIAL_SHL_ASSIGN:
698 case SPECIAL_SHR_ASSIGN:
699 case SPECIAL_OR_ASSIGN:
700 case SPECIAL_XOR_ASSIGN:
701 case SPECIAL_MUL_ASSIGN:
702 case SPECIAL_DIV_ASSIGN:
703 binop_expr = binop_expression(expr->left,
704 op_remove_assign(expr->op),
705 expr->right);
706 if (get_absolute_rl(binop_expr, &rl)) {
707 rl = cast_rl(left_type, rl);
708 set_extra_mod(name, sym, alloc_estate_rl(rl));
709 goto free;
710 }
711 break;
712 }
713 rl = cast_rl(left_type, alloc_rl(res_min, res_max));
714 set_extra_mod(name, sym, alloc_estate_rl(rl));
715 free:
716 free_string(name);
717 }
718
719 static struct smatch_state *increment_state(struct smatch_state *state)
720 {
721 sval_t min = estate_min(state);
722 sval_t max = estate_max(state);
723
724 if (!estate_rl(state))
725 return NULL;
726
727 if (inside_loop())
728 max = sval_type_max(max.type);
729
730 if (!sval_is_min(min) && !sval_is_max(min))
731 min.value++;
732 if (!sval_is_min(max) && !sval_is_max(max))
733 max.value++;
734 return alloc_estate_range(min, max);
735 }
736
737 static struct smatch_state *decrement_state(struct smatch_state *state)
738 {
739 sval_t min = estate_min(state);
740 sval_t max = estate_max(state);
741
742 if (!estate_rl(state))
743 return NULL;
744
745 if (inside_loop())
746 min = sval_type_min(min.type);
747
748 if (!sval_is_min(min) && !sval_is_max(min))
749 min.value--;
750 if (!sval_is_min(max) && !sval_is_max(max))
751 max.value--;
752 return alloc_estate_range(min, max);
753 }
754
755 static void unop_expr(struct expression *expr)
756 {
757 struct smatch_state *state;
758
759 if (expr->smatch_flags & Handled)
760 return;
761
762 switch (expr->op) {
763 case SPECIAL_INCREMENT:
764 state = get_state_expr(SMATCH_EXTRA, expr->unop);
765 state = increment_state(state);
766 if (!state)
767 state = alloc_estate_whole(get_type(expr));
768 set_extra_expr_mod(expr->unop, state);
769 break;
770 case SPECIAL_DECREMENT:
771 state = get_state_expr(SMATCH_EXTRA, expr->unop);
772 state = decrement_state(state);
773 if (!state)
774 state = alloc_estate_whole(get_type(expr));
775 set_extra_expr_mod(expr->unop, state);
776 break;
777 default:
778 return;
779 }
780 }
781
782 static void asm_expr(struct statement *stmt)
783 {
784
785 struct expression *expr;
786 struct symbol *type;
787 int state = 0;
788
789 FOR_EACH_PTR(stmt->asm_outputs, expr) {
790 switch (state) {
791 case 0: /* identifier */
792 case 1: /* constraint */
793 state++;
794 continue;
795 case 2: /* expression */
796 state = 0;
797 type = get_type(strip_expr(expr));
798 set_extra_expr_mod(expr, alloc_estate_whole(type));
799 continue;
800 }
801 } END_FOR_EACH_PTR(expr);
802 }
803
804 static void delete_state_tracker(struct tracker *t)
805 {
806 remove_from_equiv(t->name, t->sym);
807 delete_state(t->owner, t->name, t->sym);
808 }
809
810 static void scoped_state_extra(const char *name, struct symbol *sym)
811 {
812 struct tracker *t;
813
814 t = alloc_tracker(SMATCH_EXTRA, name, sym);
815 add_scope_hook((scope_hook *)&delete_state_tracker, t);
816 }
817
818 static void match_declarations(struct symbol *sym)
819 {
820 const char *name;
821
822 if (sym->ident) {
823 name = sym->ident->name;
824 if (!sym->initializer) {
825 set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
826 scoped_state_extra(name, sym);
827 }
828 }
829 }
830
831 static void check_dereference(struct expression *expr)
832 {
833 if (outside_of_function())
834 return;
835 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
836 }
837
838 static void match_dereferences(struct expression *expr)
839 {
840 if (expr->type != EXPR_PREOP)
841 return;
842 check_dereference(expr->unop);
843 }
844
845 static void match_pointer_as_array(struct expression *expr)
846 {
847 if (!is_array(expr))
848 return;
849 check_dereference(expr->unop->left);
850 }
851
852 static void set_param_dereferenced(struct expression *arg, char *key, char *unused)
853 {
854 struct symbol *sym;
855 char *name;
856
857 name = get_variable_from_key(arg, key, &sym);
858 if (!name || !sym)
859 goto free;
860
861 set_extra_nomod(name, sym, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
862
863 free:
864 free_string(name);
865 }
866
867 static void match_function_def(struct symbol *sym)
868 {
869 struct symbol *arg;
870
871 FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
872 if (!arg->ident)
873 continue;
874 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
875 } END_FOR_EACH_PTR(arg);
876 }
877
878 static sval_t add_one(sval_t sval)
879 {
880 sval.value++;
881 return sval;
882 }
883
884 static sval_t sub_one(sval_t sval)
885 {
886 sval.value--;
887 return sval;
888 }
889
890 static void handle_comparison(struct symbol *type, struct expression *left, int op, struct expression *right)
891 {
892 struct range_list *left_orig;
893 struct range_list *left_true;
894 struct range_list *left_false;
895 struct range_list *right_orig;
896 struct range_list *right_true;
897 struct range_list *right_false;
898 struct smatch_state *left_true_state;
899 struct smatch_state *left_false_state;
900 struct smatch_state *right_true_state;
901 struct smatch_state *right_false_state;
902 sval_t min, max, dummy, hard_max;
903 int left_postop = 0;
904 int right_postop = 0;
905
906 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
907 if (left->type == EXPR_POSTOP) {
908 left->smatch_flags |= Handled;
909 left_postop = left->op;
910 }
911 left = strip_expr(left->unop);
912 }
913 while (left->type == EXPR_ASSIGNMENT)
914 left = strip_expr(left->left);
915
916 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
917 if (right->type == EXPR_POSTOP) {
918 right->smatch_flags |= Handled;
919 right_postop = right->op;
920 }
921 right = strip_expr(right->unop);
922 }
923
924 if (get_implied_rl(left, &left_orig)) {
925 left_orig = cast_rl(type, left_orig);
926 } else {
927 min = sval_type_min(get_type(left));
928 max = sval_type_max(get_type(left));
929 left_orig = cast_rl(type, alloc_rl(min, max));
930 }
931
932 if (get_implied_rl(right, &right_orig)) {
933 right_orig = cast_rl(type, right_orig);
934 } else {
935 min = sval_type_min(get_type(right));
936 max = sval_type_max(get_type(right));
937 right_orig = cast_rl(type, alloc_rl(min, max));
938 }
939 min = sval_type_min(type);
940 max = sval_type_max(type);
941
942 left_true = clone_rl(left_orig);
943 left_false = clone_rl(left_orig);
944 right_true = clone_rl(right_orig);
945 right_false = clone_rl(right_orig);
946
947 switch (op) {
948 case '<':
949 case SPECIAL_UNSIGNED_LT:
950 left_true = remove_range(left_orig, rl_max(right_orig), max);
951 if (!sval_is_min(rl_min(right_orig))) {
952 left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
953 }
954
955 right_true = remove_range(right_orig, min, rl_min(left_orig));
956 if (!sval_is_max(rl_max(left_orig)))
957 right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
958 break;
959 case SPECIAL_UNSIGNED_LTE:
960 case SPECIAL_LTE:
961 if (!sval_is_max(rl_max(right_orig)))
962 left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
963 left_false = remove_range(left_orig, min, rl_min(right_orig));
964
965 if (!sval_is_min(rl_min(left_orig)))
966 right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
967 right_false = remove_range(right_orig, rl_max(left_orig), max);
968
969 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
970 left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
971 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
972 right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
973 break;
974 case SPECIAL_EQUAL:
975 if (!sval_is_max(rl_max(right_orig))) {
976 left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
977 }
978 if (!sval_is_min(rl_min(right_orig))) {
979 left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
980 }
981 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
982 left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
983
984 if (!sval_is_max(rl_max(left_orig)))
985 right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
986 if (!sval_is_min(rl_min(left_orig)))
987 right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
988 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
989 right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
990 break;
991 case SPECIAL_UNSIGNED_GTE:
992 case SPECIAL_GTE:
993 if (!sval_is_min(rl_min(right_orig)))
994 left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
995 left_false = remove_range(left_orig, rl_max(right_orig), max);
996
997 if (!sval_is_max(rl_max(left_orig)))
998 right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
999 right_false = remove_range(right_orig, min, rl_min(left_orig));
1000
1001 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
1002 right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
1003 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
1004 left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
1005 break;
1006 case '>':
1007 case SPECIAL_UNSIGNED_GT:
1008 left_true = remove_range(left_orig, min, rl_min(right_orig));
1009 if (!sval_is_max(rl_max(right_orig)))
1010 left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
1011
1012 right_true = remove_range(right_orig, rl_max(left_orig), max);
1013 if (!sval_is_min(rl_min(left_orig)))
1014 right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
1015 break;
1016 case SPECIAL_NOTEQUAL:
1017 if (!sval_is_max(rl_max(right_orig)))
1018 left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
1019 if (!sval_is_min(rl_min(right_orig)))
1020 left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
1021 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
1022 left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
1023
1024 if (!sval_is_max(rl_max(left_orig)))
1025 right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
1026 if (!sval_is_min(rl_min(left_orig)))
1027 right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
1028 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
1029 right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
1030 break;
1031 default:
1032 return;
1033 }
1034
1035 left_true = rl_truncate_cast(get_type(left), left_true);
1036 left_false = rl_truncate_cast(get_type(left), left_false);
1037 right_true = rl_truncate_cast(get_type(right), right_true);
1038 right_false = rl_truncate_cast(get_type(right), right_false);
1039
1040 left_true_state = alloc_estate_rl(left_true);
1041 left_false_state = alloc_estate_rl(left_false);
1042 right_true_state = alloc_estate_rl(right_true);
1043 right_false_state = alloc_estate_rl(right_false);
1044
1045 switch (op) {
1046 case '<':
1047 case SPECIAL_UNSIGNED_LT:
1048 case SPECIAL_UNSIGNED_LTE:
1049 case SPECIAL_LTE:
1050 if (get_hard_max(right, &dummy))
1051 estate_set_hard_max(left_true_state);
1052 if (get_hard_max(left, &dummy))
1053 estate_set_hard_max(right_false_state);
1054 break;
1055 case '>':
1056 case SPECIAL_UNSIGNED_GT:
1057 case SPECIAL_UNSIGNED_GTE:
1058 case SPECIAL_GTE:
1059 if (get_hard_max(left, &dummy))
1060 estate_set_hard_max(right_true_state);
1061 if (get_hard_max(right, &dummy))
1062 estate_set_hard_max(left_false_state);
1063 break;
1064 }
1065
1066 switch (op) {
1067 case '<':
1068 case SPECIAL_UNSIGNED_LT:
1069 case SPECIAL_UNSIGNED_LTE:
1070 case SPECIAL_LTE:
1071 if (get_hard_max(right, &hard_max)) {
1072 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1073 hard_max.value--;
1074 estate_set_fuzzy_max(left_true_state, hard_max);
1075 }
1076 if (get_implied_value(right, &hard_max)) {
1077 if (op == SPECIAL_UNSIGNED_LTE ||
1078 op == SPECIAL_LTE)
1079 hard_max.value++;
1080 estate_set_fuzzy_max(left_false_state, hard_max);
1081 }
1082 if (get_hard_max(left, &hard_max)) {
1083 if (op == SPECIAL_UNSIGNED_LTE ||
1084 op == SPECIAL_LTE)
1085 hard_max.value--;
1086 estate_set_fuzzy_max(right_false_state, hard_max);
1087 }
1088 if (get_implied_value(left, &hard_max)) {
1089 if (op == '<' || op == SPECIAL_UNSIGNED_LT)
1090 hard_max.value++;
1091 estate_set_fuzzy_max(right_true_state, hard_max);
1092 }
1093 break;
1094 case '>':
1095 case SPECIAL_UNSIGNED_GT:
1096 case SPECIAL_UNSIGNED_GTE:
1097 case SPECIAL_GTE:
1098 if (get_hard_max(left, &hard_max)) {
1099 if (op == '>' || op == SPECIAL_UNSIGNED_GT)
1100 hard_max.value--;
1101 estate_set_fuzzy_max(right_true_state, hard_max);
1102 }
1103 if (get_implied_value(left, &hard_max)) {
1104 if (op == SPECIAL_UNSIGNED_GTE ||
1105 op == SPECIAL_GTE)
1106 hard_max.value++;
1107 estate_set_fuzzy_max(right_false_state, hard_max);
1108 }
1109 if (get_hard_max(right, &hard_max)) {
1110 if (op == SPECIAL_UNSIGNED_LTE ||
1111 op == SPECIAL_LTE)
1112 hard_max.value--;
1113 estate_set_fuzzy_max(left_false_state, hard_max);
1114 }
1115 if (get_implied_value(right, &hard_max)) {
1116 if (op == '>' ||
1117 op == SPECIAL_UNSIGNED_GT)
1118 hard_max.value++;
1119 estate_set_fuzzy_max(left_true_state, hard_max);
1120 }
1121 break;
1122 case SPECIAL_EQUAL:
1123 if (get_hard_max(left, &hard_max))
1124 estate_set_fuzzy_max(right_true_state, hard_max);
1125 if (get_hard_max(right, &hard_max))
1126 estate_set_fuzzy_max(left_true_state, hard_max);
1127 break;
1128 }
1129
1130 if (get_hard_max(left, &hard_max)) {
1131 estate_set_hard_max(left_true_state);
1132 estate_set_hard_max(left_false_state);
1133 }
1134 if (get_hard_max(right, &hard_max)) {
1135 estate_set_hard_max(right_true_state);
1136 estate_set_hard_max(right_false_state);
1137 }
1138
1139 if (left_postop == SPECIAL_INCREMENT) {
1140 left_true_state = increment_state(left_true_state);
1141 left_false_state = increment_state(left_false_state);
1142 }
1143 if (left_postop == SPECIAL_DECREMENT) {
1144 left_true_state = decrement_state(left_true_state);
1145 left_false_state = decrement_state(left_false_state);
1146 }
1147 if (right_postop == SPECIAL_INCREMENT) {
1148 right_true_state = increment_state(right_true_state);
1149 right_false_state = increment_state(right_false_state);
1150 }
1151 if (right_postop == SPECIAL_DECREMENT) {
1152 right_true_state = decrement_state(right_true_state);
1153 right_false_state = decrement_state(right_false_state);
1154 }
1155
1156 set_extra_expr_true_false(left, left_true_state, left_false_state);
1157 set_extra_expr_true_false(right, right_true_state, right_false_state);
1158 }
1159
1160 static int opposite_op(int op)
1161 {
1162 switch (op) {
1163 case '+':
1164 return '-';
1165 case '-':
1166 return '+';
1167 case '*':
1168 return '/';
1169 }
1170 return 0;
1171 }
1172
1173 static int is_simple_math(struct expression *expr)
1174 {
1175 if (!expr)
1176 return 0;
1177 if (expr->type != EXPR_BINOP)
1178 return 0;
1179 if (!opposite_op(expr->op))
1180 return 0;
1181 return 1;
1182 }
1183
1184 static void move_known_values(struct expression **left_p, struct expression **right_p)
1185 {
1186 struct expression *left = *left_p;
1187 struct expression *right = *right_p;
1188 sval_t sval;
1189
1190 if (get_implied_value(left, &sval)) {
1191 if (!is_simple_math(right))
1192 return;
1193 if (right->op == '*') {
1194 sval_t divisor;
1195
1196 if (!get_value(right->right, &divisor))
1197 return;
1198 if (divisor.value == 0 && sval.value % divisor.value)
1199 return;
1200 *left_p = binop_expression(left, opposite_op(right->op), right->right);
1201 *right_p = right->left;
1202 return;
1203 }
1204 if (right->op == '+' && get_value(right->left, &sval)) {
1205 *left_p = binop_expression(left, opposite_op(right->op), right->left);
1206 *right_p = right->right;
1207 return;
1208 }
1209 if (get_value(right->right, &sval)) {
1210 *left_p = binop_expression(left, opposite_op(right->op), right->right);
1211 *right_p = right->left;
1212 return;
1213 }
1214 return;
1215 }
1216 if (get_implied_value(right, &sval)) {
1217 if (!is_simple_math(left))
1218 return;
1219 if (left->op == '*') {
1220 sval_t divisor;
1221
1222 if (!get_value(left->right, &divisor))
1223 return;
1224 if (divisor.value == 0 && sval.value % divisor.value)
1225 return;
1226 *right_p = binop_expression(right, opposite_op(left->op), left->right);
1227 *left_p = left->left;
1228 return;
1229 }
1230 if (left->op == '+' && get_value(left->left, &sval)) {
1231 *right_p = binop_expression(right, opposite_op(left->op), left->left);
1232 *left_p = left->right;
1233 return;
1234 }
1235
1236 if (get_value(left->right, &sval)) {
1237 *right_p = binop_expression(right, opposite_op(left->op), left->right);
1238 *left_p = left->left;
1239 return;
1240 }
1241 return;
1242 }
1243 }
1244
1245 static int match_func_comparison(struct expression *expr)
1246 {
1247 struct expression *left = strip_expr(expr->left);
1248 struct expression *right = strip_expr(expr->right);
1249 sval_t sval;
1250
1251 /*
1252 * fixme: think about this harder. We should always be trying to limit
1253 * the non-call side as well. If we can't determine the limitter does
1254 * that mean we aren't querying the database and are missing important
1255 * information?
1256 */
1257
1258 if (left->type == EXPR_CALL) {
1259 if (get_implied_value(left, &sval)) {
1260 handle_comparison(get_type(expr), left, expr->op, right);
1261 return 1;
1262 }
1263 if (!get_implied_value(right, &sval))
1264 return 1;
1265 function_comparison(expr->op, left, sval, 1);
1266 return 1;
1267 }
1268
1269 if (right->type == EXPR_CALL) {
1270 if (get_implied_value(right, &sval)) {
1271 handle_comparison(get_type(expr), left, expr->op, right);
1272 return 1;
1273 }
1274 if (!get_implied_value(left, &sval))
1275 return 1;
1276 function_comparison(expr->op, right, sval, 0);
1277 return 1;
1278 }
1279
1280 return 0;
1281 }
1282
1283 static void match_comparison(struct expression *expr)
1284 {
1285 struct expression *left_orig = strip_expr(expr->left);
1286 struct expression *right_orig = strip_expr(expr->right);
1287 struct expression *left, *right;
1288 struct expression *prev;
1289 struct symbol *type;
1290
1291 if (match_func_comparison(expr))
1292 return;
1293
1294 type = get_type(expr);
1295 if (!type)
1296 type = &llong_ctype;
1297
1298 left = left_orig;
1299 right = right_orig;
1300 move_known_values(&left, &right);
1301 handle_comparison(type, left, expr->op, right);
1302
1303 prev = get_assigned_expr(left_orig);
1304 if (is_simple_math(prev) && has_variable(prev, left_orig) == 0) {
1305 left = prev;
1306 right = right_orig;
1307 move_known_values(&left, &right);
1308 handle_comparison(type, left, expr->op, right);
1309 }
1310
1311 prev = get_assigned_expr(right_orig);
1312 if (is_simple_math(prev) && has_variable(prev, right_orig) == 0) {
1313 left = left_orig;
1314 right = prev;
1315 move_known_values(&left, &right);
1316 handle_comparison(type, left, expr->op, right);
1317 }
1318 }
1319
1320 static void handle_AND_condition(struct expression *expr)
1321 {
1322 struct range_list *rl = NULL;
1323 sval_t known;
1324
1325 if (get_implied_value(expr->left, &known) && known.value > 0) {
1326 known.value--;
1327 get_absolute_rl(expr->right, &rl);
1328 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1329 set_extra_expr_true_false(expr->right, alloc_estate_rl(rl), NULL);
1330 return;
1331 }
1332
1333 if (get_implied_value(expr->right, &known) && known.value > 0) {
1334 known.value--;
1335 get_absolute_rl(expr->left, &rl);
1336 rl = remove_range(rl, sval_type_val(known.type, 0), known);
1337 set_extra_expr_true_false(expr->left, alloc_estate_rl(rl), NULL);
1338 return;
1339 }
1340 }
1341
1342 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1343 void __extra_match_condition(struct expression *expr)
1344 {
1345 struct symbol *sym;
1346 char *name;
1347 struct smatch_state *pre_state;
1348 struct smatch_state *true_state;
1349 struct smatch_state *false_state;
1350
1351 expr = strip_expr(expr);
1352 switch (expr->type) {
1353 case EXPR_CALL:
1354 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
1355 return;
1356 case EXPR_PREOP:
1357 case EXPR_SYMBOL:
1358 case EXPR_DEREF: {
1359 sval_t zero;
1360
1361 zero = sval_blank(expr);
1362 zero.value = 0;
1363
1364 name = expr_to_var_sym(expr, &sym);
1365 if (!name)
1366 return;
1367 pre_state = get_state(my_id, name, sym);
1368 true_state = estate_filter_sval(pre_state, zero);
1369 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1370 false_state = alloc_estate_sval(zero);
1371 else
1372 false_state = alloc_estate_empty();
1373 set_extra_true_false(name, sym, true_state, false_state);
1374 free_string(name);
1375 return;
1376 }
1377 case EXPR_COMPARE:
1378 match_comparison(expr);
1379 return;
1380 case EXPR_ASSIGNMENT:
1381 __extra_match_condition(expr->left);
1382 return;
1383 case EXPR_BINOP:
1384 if (expr->op == '&')
1385 handle_AND_condition(expr);
1386 return;
1387 }
1388 }
1389
1390 static void assume_indexes_are_valid(struct expression *expr)
1391 {
1392 struct expression *array_expr;
1393 int array_size;
1394 struct expression *offset;
1395 struct symbol *offset_type;
1396 struct range_list *rl_before;
1397 struct range_list *rl_after;
1398 struct range_list *filter = NULL;
1399 sval_t size;
1400
1401 expr = strip_expr(expr);
1402 if (!is_array(expr))
1403 return;
1404
1405 offset = get_array_offset(expr);
1406 offset_type = get_type(offset);
1407 if (offset_type && type_signed(offset_type)) {
1408 filter = alloc_rl(sval_type_min(offset_type),
1409 sval_type_val(offset_type, -1));
1410 }
1411
1412 array_expr = strip_parens(expr->unop->left);
1413 array_size = get_real_array_size(array_expr);
1414 if (array_size > 1) {
1415 size = sval_type_val(offset_type, array_size);
1416 add_range(&filter, size, sval_type_max(offset_type));
1417 }
1418
1419 if (!filter)
1420 return;
1421 get_absolute_rl(offset, &rl_before);
1422 rl_after = rl_filter(rl_before, filter);
1423 if (rl_equiv(rl_before, rl_after))
1424 return;
1425 set_extra_expr_nomod(offset, alloc_estate_rl(rl_after));
1426 }
1427
1428 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1429 int implied_not_equal(struct expression *expr, long long val)
1430 {
1431 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1432 }
1433
1434 int implied_not_equal_name_sym(char *name, struct symbol *sym, long long val)
1435 {
1436 struct smatch_state *estate;
1437
1438 estate = get_state(SMATCH_EXTRA, name, sym);
1439 if (!estate)
1440 return 0;
1441 if (!rl_has_sval(estate_rl(estate), sval_type_val(estate_type(estate), 0)))
1442 return 1;
1443 return 0;
1444 }
1445
1446 int parent_is_null_var_sym(const char *name, struct symbol *sym)
1447 {
1448 char buf[256];
1449 char *start;
1450 char *end;
1451 struct smatch_state *state;
1452
1453 strncpy(buf, name, sizeof(buf) - 1);
1454 buf[sizeof(buf) - 1] = '\0';
1455
1456 start = &buf[0];
1457 while ((*start == '&'))
1458 start++;
1459
1460 while ((end = strrchr(start, '-'))) {
1461 *end = '\0';
1462 state = get_state(SMATCH_EXTRA, start, sym);
1463 if (!state)
1464 continue;
1465 if (estate_min(state).value == 0 &&
1466 estate_max(state).value == 0)
1467 return 1;
1468 return 0;
1469 }
1470 return 0;
1471 }
1472
1473 int parent_is_null(struct expression *expr)
1474 {
1475 struct symbol *sym;
1476 char *var;
1477 int ret = 0;
1478
1479 expr = strip_expr(expr);
1480 var = expr_to_var_sym(expr, &sym);
1481 if (!var || !sym)
1482 goto free;
1483 ret = parent_is_null_var_sym(var, sym);
1484 free:
1485 free_string(var);
1486 return ret;
1487 }
1488
1489 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1490 {
1491 if (estate_is_whole(state))
1492 return;
1493 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1494 if (estate_has_fuzzy_max(state))
1495 sql_insert_caller_info(call, FUZZY_MAX, param, printed_name,
1496 sval_to_str(estate_get_fuzzy_max(state)));
1497 }
1498
1499 static void db_limited_before(void)
1500 {
1501 unmatched_stree = clone_stree(__get_cur_stree());
1502 }
1503
1504 static void db_limited_after(void)
1505 {
1506 free_stree(&unmatched_stree);
1507 }
1508
1509 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value, int mod)
1510 {
1511 struct expression *arg;
1512 char *name;
1513 struct symbol *sym;
1514 struct sm_state *sm;
1515 struct symbol *type;
1516 struct range_list *rl;
1517 struct range_list *limit;
1518 struct range_list *new;
1519
1520 while (expr->type == EXPR_ASSIGNMENT)
1521 expr = strip_expr(expr->right);
1522 if (expr->type != EXPR_CALL)
1523 return;
1524
1525 arg = get_argument_from_call_expr(expr->args, param);
1526 if (!arg)
1527 return;
1528
1529 name = get_variable_from_key(arg, key, &sym);
1530 if (!name || !sym)
1531 goto free;
1532
1533 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1534 type = get_member_type_from_key(arg, key);
1535 if (sm)
1536 rl = estate_rl(sm->state);
1537 else
1538 rl = alloc_whole_rl(type);
1539
1540 call_results_to_rl(expr, type, value, &limit);
1541 new = rl_intersection(rl, limit);
1542
1543 /* We want to preserve the implications here */
1544 if (sm && rl_equiv(estate_rl(sm->state), new)) {
1545 __set_sm(sm);
1546 } else {
1547 if (mod)
1548 set_extra_mod(name, sym, alloc_estate_rl(new));
1549 else
1550 set_extra_nomod(name, sym, alloc_estate_rl(new));
1551 }
1552
1553 free:
1554 free_string(name);
1555 }
1556
1557 static void db_param_limit(struct expression *expr, int param, char *key, char *value)
1558 {
1559 db_param_limit_filter(expr, param, key, value, 0);
1560 }
1561
1562 static void db_param_filter(struct expression *expr, int param, char *key, char *value)
1563 {
1564 db_param_limit_filter(expr, param, key, value, 1);
1565 }
1566
1567 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1568 {
1569 struct expression *arg;
1570 char *name;
1571 struct symbol *sym;
1572 struct symbol *type;
1573 struct smatch_state *state;
1574 struct range_list *added = NULL;
1575 struct range_list *new;
1576
1577 while (expr->type == EXPR_ASSIGNMENT)
1578 expr = strip_expr(expr->right);
1579 if (expr->type != EXPR_CALL)
1580 return;
1581
1582 arg = get_argument_from_call_expr(expr->args, param);
1583 if (!arg)
1584 return;
1585 name = get_variable_from_key(arg, key, &sym);
1586 if (!name || !sym)
1587 goto free;
1588
1589 type = get_member_type_from_key(arg, key);
1590 state = get_state(SMATCH_EXTRA, name, sym);
1591 if (state) {
1592 call_results_to_rl(expr, type, value, &added);
1593 new = rl_union(estate_rl(state), added);
1594 } else {
1595 new = alloc_whole_rl(type);
1596 }
1597
1598 set_extra_mod(name, sym, alloc_estate_rl(new));
1599 free:
1600 free_string(name);
1601 }
1602
1603 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1604 {
1605 struct symbol *type;
1606 struct symbol *sym;
1607 char *name;
1608 struct range_list *rl;
1609
1610 if (expr->type != EXPR_ASSIGNMENT)
1611 return;
1612
1613 name = return_state_to_var_sym(expr, param, key, &sym);
1614 if (!name || !sym)
1615 goto free;
1616 type = get_member_type_from_key(expr->left, key);
1617 if (!type)
1618 return;
1619 call_results_to_rl(expr->right, type, value, &rl);
1620 set_extra_mod(name, sym, alloc_estate_rl(rl));
1621
1622 free:
1623 free_string(name);
1624 }
1625
1626 static char *in_terms_of_param_math(struct expression *expr, char *printed_name)
1627 {
1628 struct symbol *sym;
1629 char *var;
1630 char buf[256];
1631 char *ret = NULL;
1632
1633 var = expr_to_var_sym(expr, &sym);
1634 if (!var || !sym)
1635 goto free;
1636 snprintf(buf, sizeof(buf), "%s%s", var, printed_name + 2);
1637
1638 ret = get_value_in_terms_of_parameter_math_var_sym(buf, sym);
1639
1640 free:
1641 free_string(var);
1642 return ret;
1643 }
1644
1645 static void returned_member_callback(int return_id, char *return_ranges, struct expression *expr, char *printed_name, struct smatch_state *state)
1646 {
1647 char buf[256];
1648 char *math_str;
1649 sval_t sval;
1650
1651 /* these are handled in smatch_param_filter/set/limit.c */
1652 if (printed_name[0] != '*' &&
1653 !strchr(printed_name, '.') && !strchr(printed_name, '-'))
1654 return;
1655
1656 if (estate_get_single_value(state, &sval)) {
1657 sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1658 printed_name, sval_to_str(sval));
1659 return;
1660 }
1661
1662 math_str = in_terms_of_param_math(expr, printed_name);
1663 if (math_str) {
1664 snprintf(buf, sizeof(buf), "%s[%s]", state->name, math_str);
1665 sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1666 printed_name, buf);
1667 return;
1668 }
1669
1670 if (estate_is_whole(state))
1671 return;
1672
1673 sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1674 printed_name, state->name);
1675 }
1676
1677 static void match_call_info(struct expression *expr)
1678 {
1679 struct smatch_state *state;
1680 struct range_list *rl = NULL;
1681 struct expression *arg;
1682 struct symbol *type;
1683 int i = 0;
1684
1685 FOR_EACH_PTR(expr->args, arg) {
1686 type = get_arg_type(expr->fn, i);
1687
1688 if (get_implied_rl(arg, &rl))
1689 rl = cast_rl(type, rl);
1690 else
1691 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1692
1693 if (!is_whole_rl(rl))
1694 sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1695 state = get_state_expr(SMATCH_EXTRA, arg);
1696 if (estate_has_fuzzy_max(state)) {
1697 sql_insert_caller_info(expr, FUZZY_MAX, i, "$$",
1698 sval_to_str(estate_get_fuzzy_max(state)));
1699 }
1700 i++;
1701 } END_FOR_EACH_PTR(arg);
1702 }
1703
1704 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1705 {
1706 struct range_list *rl = NULL;
1707 struct smatch_state *state;
1708 struct symbol *type;
1709 char fullname[256];
1710
1711 if (strcmp(key, "*$$") == 0)
1712 snprintf(fullname, sizeof(fullname), "*%s", name);
1713 else if (strncmp(key, "$$", 2) == 0)
1714 snprintf(fullname, 256, "%s%s", name, key + 2);
1715 else
1716 return;
1717
1718 type = get_member_type_from_key(symbol_expression(sym), key);
1719 str_to_rl(type, value, &rl);
1720 state = alloc_estate_rl(rl);
1721 set_state(SMATCH_EXTRA, fullname, sym, state);
1722 }
1723
1724 static void set_param_hard_max(const char *name, struct symbol *sym, char *key, char *value)
1725 {
1726 struct range_list *rl = NULL;
1727 struct smatch_state *state;
1728 struct symbol *type;
1729 char fullname[256];
1730 sval_t max;
1731
1732 if (strcmp(key, "*$$") == 0)
1733 snprintf(fullname, sizeof(fullname), "*%s", name);
1734 else if (strncmp(key, "$$", 2) == 0)
1735 snprintf(fullname, 256, "%s%s", name, key + 2);
1736 else
1737 return;
1738
1739 state = get_state(SMATCH_EXTRA, fullname, sym);
1740 if (!state)
1741 return;
1742 type = get_member_type_from_key(symbol_expression(sym), key);
1743 str_to_rl(type, value, &rl);
1744 if (!rl_to_sval(rl, &max))
1745 return;
1746 estate_set_fuzzy_max(state, max);
1747 }
1748
1749 void register_smatch_extra(int id)
1750 {
1751 my_id = id;
1752
1753 add_merge_hook(my_id, &merge_estates);
1754 add_unmatched_state_hook(my_id, &unmatched_state);
1755 add_hook(&match_function_def, FUNC_DEF_HOOK);
1756 add_hook(&match_declarations, DECLARATION_HOOK);
1757 select_caller_info_hook(set_param_value, PARAM_VALUE);
1758 select_caller_info_hook(set_param_hard_max, FUZZY_MAX);
1759 select_return_states_hook(RETURN_VALUE, &db_returned_member_info);
1760 select_return_states_before(&db_limited_before);
1761 select_return_states_hook(LIMITED_VALUE, &db_param_limit);
1762 select_return_states_hook(FILTER_VALUE, &db_param_filter);
1763 select_return_states_hook(ADDED_VALUE, &db_param_add);
1764 select_return_states_after(&db_limited_after);
1765 }
1766
1767 void register_smatch_extra_late(int id)
1768 {
1769 add_hook(&match_dereferences, DEREF_HOOK);
1770 add_hook(&match_pointer_as_array, OP_HOOK);
1771 select_call_implies_hook(DEREFERENCE, &set_param_dereferenced);
1772 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1773 add_hook(&match_assign, ASSIGNMENT_HOOK);
1774 add_hook(&match_assign, GLOBAL_ASSIGNMENT_HOOK);
1775 add_hook(&unop_expr, OP_HOOK);
1776 add_hook(&asm_expr, ASM_HOOK);
1777
1778 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1779 add_member_info_callback(my_id, struct_member_callback);
1780 add_returned_member_callback(my_id, returned_member_callback);
1781
1782 add_hook(&assume_indexes_are_valid, OP_HOOK);
1783 }
Static analysis for C