2 * Copyright (C) 2010 Dan Carpenter.
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.
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.
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
20 #include "smatch_slist.h"
21 #include "smatch_extra.h"
23 static struct range_list
*_get_rl(struct expression
*expr
, int implied
, int *recurse_cnt
);
24 static struct range_list
*handle_variable(struct expression
*expr
, int implied
, int *recurse_cnt
);
25 static struct range_list
*(*custom_handle_variable
)(struct expression
*expr
);
27 static int get_implied_value_internal(struct expression
*expr
, sval_t
*sval
, int *recurse_cnt
);
28 static int get_absolute_rl_internal(struct expression
*expr
, struct range_list
**rl
, int *recurse_cnt
);
30 static sval_t zero
= {.type
= &int_ctype
, {.value
= 0} };
31 static sval_t one
= {.type
= &int_ctype
, {.value
= 1} };
33 struct range_list
*rl_zero(void)
35 static struct range_list
*zero_perm
;
38 zero_perm
= clone_rl_permanent(alloc_rl(zero
, zero
));
42 struct range_list
*rl_one(void)
44 static struct range_list
*one_perm
;
47 one_perm
= clone_rl_permanent(alloc_rl(one
, one
));
61 static struct range_list
*last_stmt_rl(struct statement
*stmt
, int implied
, int *recurse_cnt
)
63 struct expression
*expr
;
68 stmt
= last_ptr_list((struct ptr_list
*)stmt
->stmts
);
69 if (stmt
->type
== STMT_LABEL
) {
70 if (stmt
->label_statement
&&
71 stmt
->label_statement
->type
== STMT_EXPRESSION
)
72 expr
= stmt
->label_statement
->expression
;
75 } else if (stmt
->type
== STMT_EXPRESSION
) {
76 expr
= stmt
->expression
;
80 return _get_rl(expr
, implied
, recurse_cnt
);
83 static struct range_list
*handle_expression_statement_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
85 return last_stmt_rl(get_expression_statement(expr
), implied
, recurse_cnt
);
88 static struct range_list
*handle_ampersand_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
90 struct range_list
*rl
;
93 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
95 if (get_mtag_sval(expr
, &sval
))
96 return alloc_rl(sval
, sval
);
97 /* FIXME: are these lines still required ? */
98 if (get_address_rl(expr
, &rl
))
100 return alloc_rl(valid_ptr_min_sval
, valid_ptr_max_sval
);
103 static struct range_list
*handle_negate_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
105 if (known_condition_true(expr
->unop
))
107 if (known_condition_false(expr
->unop
))
110 if (implied
== RL_EXACT
)
113 if (implied_condition_true(expr
->unop
))
115 if (implied_condition_false(expr
->unop
))
117 return alloc_rl(zero
, one
);
120 static struct range_list
*handle_bitwise_negate(struct expression
*expr
, int implied
, int *recurse_cnt
)
122 struct range_list
*rl
;
125 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
126 if (!rl_to_sval(rl
, &sval
))
128 sval
= sval_preop(sval
, '~');
129 sval_cast(get_type(expr
->unop
), sval
);
130 return alloc_rl(sval
, sval
);
133 static struct range_list
*handle_minus_preop(struct expression
*expr
, int implied
, int *recurse_cnt
)
135 struct range_list
*rl
;
138 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
139 min
= sval_preop(rl_max(rl
), '-');
140 max
= sval_preop(rl_min(rl
), '-');
141 return alloc_rl(min
, max
);
144 static struct range_list
*handle_preop_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
148 return handle_ampersand_rl(expr
, implied
, recurse_cnt
);
150 return handle_negate_rl(expr
, implied
, recurse_cnt
);
152 return handle_bitwise_negate(expr
, implied
, recurse_cnt
);
154 return handle_minus_preop(expr
, implied
, recurse_cnt
);
156 return handle_variable(expr
, implied
, recurse_cnt
);
158 return handle_expression_statement_rl(expr
, implied
, recurse_cnt
);
164 static struct range_list
*handle_divide_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
166 struct range_list
*left_rl
, *right_rl
;
169 type
= get_type(expr
);
171 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
172 left_rl
= cast_rl(type
, left_rl
);
173 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
174 right_rl
= cast_rl(type
, right_rl
);
176 if (!left_rl
|| !right_rl
)
179 if (implied
!= RL_REAL_ABSOLUTE
) {
180 if (is_whole_rl(left_rl
) || is_whole_rl(right_rl
))
184 return rl_binop(left_rl
, '/', right_rl
);
187 static int handle_offset_subtraction(struct expression
*expr
)
189 struct expression
*left
, *right
;
190 struct symbol
*left_sym
, *right_sym
;
192 int left_offset
, right_offset
;
194 type
= get_type(expr
);
195 if (!type
|| type
->type
!= SYM_PTR
)
197 type
= get_real_base_type(type
);
198 if (!type
|| (type_bits(type
) != 8 && (type
!= &void_ctype
)))
201 left
= strip_expr(expr
->left
);
202 right
= strip_expr(expr
->right
);
204 if (left
->type
!= EXPR_PREOP
|| left
->op
!= '&')
206 left
= strip_expr(left
->unop
);
208 left_sym
= expr_to_sym(left
);
209 right_sym
= expr_to_sym(right
);
210 if (!left_sym
|| left_sym
!= right_sym
)
213 left_offset
= get_member_offset_from_deref(left
);
214 if (right
->type
== EXPR_SYMBOL
)
217 if (right
->type
!= EXPR_PREOP
|| right
->op
!= '&')
219 right
= strip_expr(right
->unop
);
220 right_offset
= get_member_offset_from_deref(right
);
222 if (left_offset
< 0 || right_offset
< 0)
225 return left_offset
- right_offset
;
228 static struct range_list
*handle_subtract_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
231 struct range_list
*left_orig
, *right_orig
;
232 struct range_list
*left_rl
, *right_rl
;
233 sval_t max
, min
, tmp
;
237 type
= get_type(expr
);
239 offset
= handle_offset_subtraction(expr
);
244 return alloc_rl(tmp
, tmp
);
247 comparison
= get_comparison(expr
->left
, expr
->right
);
249 left_orig
= _get_rl(expr
->left
, implied
, recurse_cnt
);
250 left_rl
= cast_rl(type
, left_orig
);
251 right_orig
= _get_rl(expr
->right
, implied
, recurse_cnt
);
252 right_rl
= cast_rl(type
, right_orig
);
254 if ((!left_rl
|| !right_rl
) &&
255 (implied
== RL_EXACT
|| implied
== RL_HARD
|| implied
== RL_FUZZY
))
259 left_rl
= alloc_whole_rl(type
);
261 right_rl
= alloc_whole_rl(type
);
263 /* negative values complicate everything fix this later */
264 if (sval_is_negative(rl_min(right_rl
)))
266 max
= rl_max(left_rl
);
267 min
= sval_type_min(type
);
269 switch (comparison
) {
271 case SPECIAL_UNSIGNED_GT
:
272 min
= sval_type_val(type
, 1);
273 max
= rl_max(left_rl
);
276 case SPECIAL_UNSIGNED_GTE
:
277 min
= sval_type_val(type
, 0);
278 max
= rl_max(left_rl
);
281 min
= sval_type_val(type
, 0);
282 max
= sval_type_val(type
, 0);
285 case SPECIAL_UNSIGNED_LT
:
286 max
= sval_type_val(type
, -1);
289 case SPECIAL_UNSIGNED_LTE
:
290 max
= sval_type_val(type
, 0);
293 if (!left_orig
|| !right_orig
)
295 return rl_binop(left_rl
, '-', right_rl
);
298 if (!sval_binop_overflows(rl_min(left_rl
), '-', rl_max(right_rl
))) {
299 tmp
= sval_binop(rl_min(left_rl
), '-', rl_max(right_rl
));
300 if (sval_cmp(tmp
, min
) > 0)
304 if (!sval_is_max(rl_max(left_rl
))) {
305 tmp
= sval_binop(rl_max(left_rl
), '-', rl_min(right_rl
));
306 if (sval_cmp(tmp
, max
) < 0)
310 if (sval_is_min(min
) && sval_is_max(max
))
313 return cast_rl(type
, alloc_rl(min
, max
));
316 static struct range_list
*handle_mod_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
318 struct range_list
*rl
;
319 sval_t left
, right
, sval
;
321 if (implied
== RL_EXACT
) {
322 if (!get_implied_value(expr
->right
, &right
))
324 if (!get_implied_value(expr
->left
, &left
))
326 sval
= sval_binop(left
, '%', right
);
327 return alloc_rl(sval
, sval
);
329 /* if we can't figure out the right side it's probably hopeless */
330 if (!get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
333 right
= sval_cast(get_type(expr
), right
);
336 rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
337 if (rl
&& rl_max(rl
).uvalue
< right
.uvalue
)
338 right
.uvalue
= rl_max(rl
).uvalue
;
340 return alloc_rl(sval_cast(right
.type
, zero
), right
);
343 static sval_t
sval_lowest_set_bit(sval_t sval
)
348 for (i
= 0; i
< 64; i
++) {
349 if (sval
.uvalue
& 1ULL << i
) {
352 sval
.uvalue
&= ~(1ULL << i
);
358 static struct range_list
*handle_bitwise_AND(struct expression
*expr
, int implied
, int *recurse_cnt
)
361 struct range_list
*left_rl
, *right_rl
;
365 if (implied
!= RL_IMPLIED
&& implied
!= RL_ABSOLUTE
&& implied
!= RL_REAL_ABSOLUTE
)
368 type
= get_type(expr
);
370 if (get_implied_value_internal(expr
->left
, &known
, recurse_cnt
)) {
373 min
= sval_lowest_set_bit(known
);
374 left_rl
= alloc_rl(min
, known
);
375 left_rl
= cast_rl(type
, left_rl
);
376 add_range(&left_rl
, sval_type_val(type
, 0), sval_type_val(type
, 0));
378 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
380 left_rl
= cast_rl(type
, left_rl
);
381 left_rl
= alloc_rl(sval_type_val(type
, 0), rl_max(left_rl
));
383 if (implied
== RL_HARD
)
385 left_rl
= alloc_whole_rl(type
);
389 new_recurse
= *recurse_cnt
;
390 if (*recurse_cnt
>= 200)
391 new_recurse
= 100; /* Let's try super hard to get the mask */
392 if (get_implied_value_internal(expr
->right
, &known
, &new_recurse
)) {
393 sval_t min
, left_max
, mod
;
395 *recurse_cnt
= new_recurse
;
397 min
= sval_lowest_set_bit(known
);
398 right_rl
= alloc_rl(min
, known
);
399 right_rl
= cast_rl(type
, right_rl
);
400 add_range(&right_rl
, sval_type_val(type
, 0), sval_type_val(type
, 0));
402 if (min
.value
!= 0) {
403 left_max
= rl_max(left_rl
);
404 mod
= sval_binop(left_max
, '%', min
);
406 left_max
= sval_binop(left_max
, '-', mod
);
408 if (left_max
.value
> 0 && sval_cmp(left_max
, rl_max(left_rl
)) < 0)
409 left_rl
= remove_range(left_rl
, left_max
, rl_max(left_rl
));
413 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
415 right_rl
= cast_rl(type
, right_rl
);
416 right_rl
= alloc_rl(sval_type_val(type
, 0), rl_max(right_rl
));
418 if (implied
== RL_HARD
)
420 right_rl
= alloc_whole_rl(type
);
424 return rl_intersection(left_rl
, right_rl
);
427 static struct range_list
*use_rl_binop(struct expression
*expr
, int implied
, int *recurse_cnt
)
430 struct range_list
*left_rl
, *right_rl
;
432 if (implied
!= RL_IMPLIED
&& implied
!= RL_ABSOLUTE
&& implied
!= RL_REAL_ABSOLUTE
)
435 type
= get_type(expr
);
437 get_absolute_rl_internal(expr
->left
, &left_rl
, recurse_cnt
);
438 get_absolute_rl_internal(expr
->right
, &right_rl
, recurse_cnt
);
439 left_rl
= cast_rl(type
, left_rl
);
440 right_rl
= cast_rl(type
, right_rl
);
441 if (!left_rl
|| !right_rl
)
444 return rl_binop(left_rl
, expr
->op
, right_rl
);
447 static struct range_list
*handle_right_shift(struct expression
*expr
, int implied
, int *recurse_cnt
)
449 struct range_list
*left_rl
;
453 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
456 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
458 max
= rl_max(left_rl
);
459 min
= rl_min(left_rl
);
461 if (implied
== RL_FUZZY
)
463 max
= sval_type_max(get_type(expr
->left
));
464 min
= sval_type_val(get_type(expr
->left
), 0);
467 if (get_implied_value_internal(expr
->right
, &right
, recurse_cnt
)) {
468 min
= sval_binop(min
, SPECIAL_RIGHTSHIFT
, right
);
469 max
= sval_binop(max
, SPECIAL_RIGHTSHIFT
, right
);
470 } else if (!sval_is_negative(min
)) {
472 max
= sval_type_max(max
.type
);
477 return alloc_rl(min
, max
);
480 static struct range_list
*handle_left_shift(struct expression
*expr
, int implied
, int *recurse_cnt
)
482 struct range_list
*left_rl
, *res
;
487 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
489 /* this is hopeless without the right side */
490 if (!get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
492 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
494 max
= rl_max(left_rl
);
495 min
= rl_min(left_rl
);
496 if (min
.value
== 0) {
501 if (implied
== RL_FUZZY
)
503 max
= sval_type_max(get_type(expr
->left
));
504 min
= sval_type_val(get_type(expr
->left
), 1);
508 max
= sval_binop(max
, SPECIAL_LEFTSHIFT
, right
);
509 min
= sval_binop(min
, SPECIAL_LEFTSHIFT
, right
);
510 res
= alloc_rl(min
, max
);
512 res
= rl_union(res
, rl_zero());
516 static struct range_list
*handle_known_binop(struct expression
*expr
)
520 if (!get_value(expr
->left
, &left
))
522 if (!get_value(expr
->right
, &right
))
524 left
= sval_binop(left
, expr
->op
, right
);
525 return alloc_rl(left
, left
);
528 static int has_actual_ranges(struct range_list
*rl
)
530 struct data_range
*tmp
;
532 FOR_EACH_PTR(rl
, tmp
) {
533 if (sval_cmp(tmp
->min
, tmp
->max
) != 0)
535 } END_FOR_EACH_PTR(tmp
);
539 static struct range_list
*handle_implied_binop(struct range_list
*left_rl
, int op
, struct range_list
*right_rl
)
541 struct range_list
*res_rl
;
542 struct data_range
*left_drange
, *right_drange
;
545 if (!left_rl
|| !right_rl
)
547 if (has_actual_ranges(left_rl
))
549 if (has_actual_ranges(right_rl
))
552 if (ptr_list_size((struct ptr_list
*)left_rl
) * ptr_list_size((struct ptr_list
*)right_rl
) > 20)
557 FOR_EACH_PTR(left_rl
, left_drange
) {
558 FOR_EACH_PTR(right_rl
, right_drange
) {
559 if ((op
== '%' || op
== '/') &&
560 right_drange
->min
.value
== 0)
562 res
= sval_binop(left_drange
->min
, op
, right_drange
->min
);
563 add_range(&res_rl
, res
, res
);
564 } END_FOR_EACH_PTR(right_drange
);
565 } END_FOR_EACH_PTR(left_drange
);
570 static struct range_list
*handle_binop_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
572 struct smatch_state
*state
;
574 struct range_list
*left_rl
, *right_rl
, *rl
;
577 rl
= handle_known_binop(expr
);
580 if (implied
== RL_EXACT
)
583 if (custom_handle_variable
) {
584 rl
= custom_handle_variable(expr
);
589 state
= get_extra_state(expr
);
590 if (state
&& !is_whole_rl(estate_rl(state
))) {
591 if (implied
!= RL_HARD
|| estate_has_hard_max(state
))
592 return clone_rl(estate_rl(state
));
595 type
= get_type(expr
);
596 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
597 left_rl
= cast_rl(type
, left_rl
);
598 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
599 right_rl
= cast_rl(type
, right_rl
);
601 if (!left_rl
&& !right_rl
)
604 rl
= handle_implied_binop(left_rl
, expr
->op
, right_rl
);
610 return handle_mod_rl(expr
, implied
, recurse_cnt
);
612 return handle_bitwise_AND(expr
, implied
, recurse_cnt
);
615 return use_rl_binop(expr
, implied
, recurse_cnt
);
616 case SPECIAL_RIGHTSHIFT
:
617 return handle_right_shift(expr
, implied
, recurse_cnt
);
618 case SPECIAL_LEFTSHIFT
:
619 return handle_left_shift(expr
, implied
, recurse_cnt
);
621 return handle_subtract_rl(expr
, implied
, recurse_cnt
);
623 return handle_divide_rl(expr
, implied
, recurse_cnt
);
626 if (!left_rl
|| !right_rl
)
629 if (sval_binop_overflows(rl_min(left_rl
), expr
->op
, rl_min(right_rl
)))
631 if (sval_binop_overflows(rl_max(left_rl
), expr
->op
, rl_max(right_rl
)))
634 min
= sval_binop(rl_min(left_rl
), expr
->op
, rl_min(right_rl
));
635 max
= sval_binop(rl_max(left_rl
), expr
->op
, rl_max(right_rl
));
637 return alloc_rl(min
, max
);
640 static int do_comparison(struct expression
*expr
)
642 struct range_list
*left_ranges
= NULL
;
643 struct range_list
*right_ranges
= NULL
;
644 int poss_true
, poss_false
;
647 type
= get_type(expr
);
648 get_absolute_rl(expr
->left
, &left_ranges
);
649 get_absolute_rl(expr
->right
, &right_ranges
);
651 left_ranges
= cast_rl(type
, left_ranges
);
652 right_ranges
= cast_rl(type
, right_ranges
);
654 poss_true
= possibly_true_rl(left_ranges
, expr
->op
, right_ranges
);
655 poss_false
= possibly_false_rl(left_ranges
, expr
->op
, right_ranges
);
657 if (!poss_true
&& !poss_false
)
659 if (poss_true
&& !poss_false
)
661 if (!poss_true
&& poss_false
)
666 static struct range_list
*handle_comparison_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
671 if (expr
->op
== SPECIAL_EQUAL
&& expr
->left
->type
== EXPR_TYPE
) {
672 struct symbol
*left
, *right
;
674 left
= get_real_base_type(expr
->left
->symbol
);
675 right
= get_real_base_type(expr
->left
->symbol
);
681 if (get_value(expr
->left
, &left
) && get_value(expr
->right
, &right
)) {
682 struct data_range tmp_left
, tmp_right
;
686 tmp_right
.min
= right
;
687 tmp_right
.max
= right
;
688 if (true_comparison_range(&tmp_left
, expr
->op
, &tmp_right
))
693 if (implied
== RL_EXACT
)
696 res
= do_comparison(expr
);
702 return alloc_rl(zero
, one
);
705 static struct range_list
*handle_logical_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
711 if (implied
== RL_EXACT
) {
712 if (get_value(expr
->left
, &left
))
714 if (get_value(expr
->right
, &right
))
717 if (get_implied_value_internal(expr
->left
, &left
, recurse_cnt
))
719 if (get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
724 case SPECIAL_LOGICAL_OR
:
725 if (left_known
&& left
.value
)
727 if (right_known
&& right
.value
)
729 if (left_known
&& right_known
)
732 case SPECIAL_LOGICAL_AND
:
733 if (left_known
&& right_known
) {
734 if (left
.value
&& right
.value
)
743 if (implied
== RL_EXACT
)
746 return alloc_rl(zero
, one
);
749 static struct range_list
*handle_conditional_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
751 struct range_list
*true_rl
, *false_rl
;
753 int final_pass_orig
= final_pass
;
755 if (known_condition_true(expr
->conditional
))
756 return _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
757 if (known_condition_false(expr
->conditional
))
758 return _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
760 if (implied
== RL_EXACT
)
763 if (implied_condition_true(expr
->conditional
))
764 return _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
765 if (implied_condition_false(expr
->conditional
))
766 return _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
769 /* this becomes a problem with deeply nested conditional statements */
773 type
= get_type(expr
);
775 __push_fake_cur_stree();
777 __split_whole_condition(expr
->conditional
);
778 true_rl
= _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
779 __push_true_states();
780 __use_false_states();
781 false_rl
= _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
782 __merge_true_states();
783 __free_fake_cur_stree();
784 final_pass
= final_pass_orig
;
786 if (!true_rl
|| !false_rl
)
788 true_rl
= cast_rl(type
, true_rl
);
789 false_rl
= cast_rl(type
, false_rl
);
791 return rl_union(true_rl
, false_rl
);
794 static int get_fuzzy_max_helper(struct expression
*expr
, sval_t
*max
)
796 struct smatch_state
*state
;
799 if (get_hard_max(expr
, &sval
)) {
804 state
= get_extra_state(expr
);
805 if (!state
|| !estate_has_fuzzy_max(state
))
807 *max
= sval_cast(get_type(expr
), estate_get_fuzzy_max(state
));
811 static int get_fuzzy_min_helper(struct expression
*expr
, sval_t
*min
)
813 struct smatch_state
*state
;
816 state
= get_extra_state(expr
);
817 if (!state
|| !estate_rl(state
))
820 sval
= estate_min(state
);
821 if (sval_is_negative(sval
) && sval_is_min(sval
))
824 if (sval_is_max(sval
))
827 *min
= sval_cast(get_type(expr
), sval
);
831 int get_const_value(struct expression
*expr
, sval_t
*sval
)
836 if (expr
->type
!= EXPR_SYMBOL
|| !expr
->symbol
)
839 if (!(sym
->ctype
.modifiers
& MOD_CONST
))
841 if (get_value(sym
->initializer
, &right
)) {
842 *sval
= sval_cast(get_type(expr
), right
);
848 struct range_list
*var_to_absolute_rl(struct expression
*expr
)
850 struct smatch_state
*state
;
851 struct range_list
*rl
;
853 state
= get_extra_state(expr
);
854 if (!state
|| is_whole_rl(estate_rl(state
))) {
855 state
= get_real_absolute_state(expr
);
856 if (state
&& state
->data
&& !estate_is_whole(state
))
857 return clone_rl(estate_rl(state
));
858 if (get_local_rl(expr
, &rl
) && !is_whole_rl(rl
))
860 if (get_db_data_rl(expr
, &rl
))
862 if (get_db_type_rl(expr
, &rl
) && !is_whole_rl(rl
))
864 return alloc_whole_rl(get_type(expr
));
866 /* err on the side of saying things are possible */
867 if (!estate_rl(state
))
868 return alloc_whole_rl(get_type(expr
));
869 return clone_rl(estate_rl(state
));
872 static struct range_list
*handle_variable(struct expression
*expr
, int implied
, int *recurse_cnt
)
874 struct smatch_state
*state
;
875 struct range_list
*rl
;
876 sval_t sval
, min
, max
;
879 if (get_const_value(expr
, &sval
))
880 return alloc_rl(sval
, sval
);
882 if (custom_handle_variable
) {
883 rl
= custom_handle_variable(expr
);
885 return var_to_absolute_rl(expr
);
889 if (implied
== RL_EXACT
)
892 if (get_mtag_sval(expr
, &sval
))
893 return alloc_rl(sval
, sval
);
895 type
= get_type(expr
);
896 if (type
&& type
->type
== SYM_FN
)
897 return alloc_rl(fn_ptr_min
, fn_ptr_max
);
903 state
= get_extra_state(expr
);
904 if (!state
|| !state
->data
) {
905 if (implied
== RL_HARD
)
907 if (get_local_rl(expr
, &rl
))
909 if (get_db_data_rl(expr
, &rl
))
911 if (get_db_type_rl(expr
, &rl
))
915 if (implied
== RL_HARD
&& !estate_has_hard_max(state
))
917 return clone_rl(estate_rl(state
));
918 case RL_REAL_ABSOLUTE
: {
919 struct smatch_state
*abs_state
;
921 state
= get_extra_state(expr
);
922 abs_state
= get_real_absolute_state(expr
);
924 if (estate_rl(state
) && estate_rl(abs_state
)) {
925 return clone_rl(rl_intersection(estate_rl(state
),
926 estate_rl(abs_state
)));
927 } else if (estate_rl(state
)) {
928 return clone_rl(estate_rl(state
));
929 } else if (estate_is_empty(state
)) {
931 * FIXME: we don't handle empty extra states correctly.
933 * The real abs rl is supposed to be filtered by the
934 * extra state if there is one. We don't bother keeping
935 * the abs state in sync all the time because we know it
936 * will be filtered later.
938 * It's not totally obvious to me how they should be
939 * handled. Perhaps we should take the whole rl and
940 * filter by the imaginary states. Perhaps we should
941 * just go with the empty state.
943 * Anyway what we currently do is return NULL here and
944 * that gets translated into the whole range in
945 * get_real_absolute_rl().
949 } else if (estate_rl(abs_state
)) {
950 return clone_rl(estate_rl(abs_state
));
953 if (get_local_rl(expr
, &rl
))
955 if (get_db_data_rl(expr
, &rl
))
957 if (get_db_type_rl(expr
, &rl
))
962 if (!get_fuzzy_min_helper(expr
, &min
))
963 min
= sval_type_min(get_type(expr
));
964 if (!get_fuzzy_max_helper(expr
, &max
))
966 /* fuzzy ranges are often inverted */
967 if (sval_cmp(min
, max
) > 0) {
972 return alloc_rl(min
, max
);
977 static sval_t
handle_sizeof(struct expression
*expr
)
982 ret
= sval_blank(expr
);
983 sym
= expr
->cast_type
;
985 sym
= evaluate_expression(expr
->cast_expression
);
987 __silence_warnings_for_stmt
= true;
992 * Expressions of restricted types will possibly get
993 * promoted - check that here. I'm not sure how this works,
994 * the problem is that sizeof(le16) shouldn't be promoted and
995 * the original code did that... Let's if zero this out and
999 if (is_restricted_type(sym
)) {
1000 if (type_bits(sym
) < bits_in_int
)
1004 if (is_fouled_type(sym
))
1007 examine_symbol_type(sym
);
1009 ret
.type
= size_t_ctype
;
1010 if (type_bits(sym
) <= 0) /* sizeof(void) */ {
1011 if (get_real_base_type(sym
) == &void_ctype
)
1016 ret
.value
= type_bytes(sym
);
1021 static struct range_list
*handle_strlen(struct expression
*expr
, int implied
, int *recurse_cnt
)
1023 struct range_list
*rl
;
1024 struct expression
*arg
;
1025 sval_t sval
= { .type
= &ulong_ctype
};
1027 if (implied
== RL_EXACT
)
1030 arg
= get_argument_from_call_expr(expr
->args
, 0);
1033 if (arg
->type
== EXPR_STRING
) {
1034 sval
.value
= arg
->string
->length
- 1;
1035 return alloc_rl(sval
, sval
);
1038 if (implied
== RL_HARD
|| implied
== RL_FUZZY
)
1041 if (get_implied_return(expr
, &rl
))
1047 static struct range_list
*handle_builtin_constant_p(struct expression
*expr
, int implied
, int *recurse_cnt
)
1049 struct expression
*arg
;
1050 struct range_list
*rl
;
1053 arg
= get_argument_from_call_expr(expr
->args
, 0);
1054 rl
= _get_rl(arg
, RL_EXACT
, recurse_cnt
);
1055 if (rl_to_sval(rl
, &sval
))
1060 static struct range_list
*handle__builtin_choose_expr(struct expression
*expr
, int implied
, int *recurse_cnt
)
1062 struct expression
*const_expr
, *expr1
, *expr2
;
1065 const_expr
= get_argument_from_call_expr(expr
->args
, 0);
1066 expr1
= get_argument_from_call_expr(expr
->args
, 1);
1067 expr2
= get_argument_from_call_expr(expr
->args
, 2);
1069 if (!get_value(const_expr
, &sval
) || !expr1
|| !expr2
)
1072 return _get_rl(expr1
, implied
, recurse_cnt
);
1073 return _get_rl(expr2
, implied
, recurse_cnt
);
1076 static struct range_list
*handle_call_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
1078 struct range_list
*rl
;
1080 if (sym_name_is("__builtin_constant_p", expr
->fn
))
1081 return handle_builtin_constant_p(expr
, implied
, recurse_cnt
);
1083 if (sym_name_is("__builtin_choose_expr", expr
->fn
))
1084 return handle__builtin_choose_expr(expr
, implied
, recurse_cnt
);
1086 if (sym_name_is("__builtin_expect", expr
->fn
) ||
1087 sym_name_is("__builtin_bswap16", expr
->fn
) ||
1088 sym_name_is("__builtin_bswap32", expr
->fn
) ||
1089 sym_name_is("__builtin_bswap64", expr
->fn
)) {
1090 struct expression
*arg
;
1092 arg
= get_argument_from_call_expr(expr
->args
, 0);
1093 return _get_rl(arg
, implied
, recurse_cnt
);
1096 if (sym_name_is("strlen", expr
->fn
))
1097 return handle_strlen(expr
, implied
, recurse_cnt
);
1099 if (implied
== RL_EXACT
|| implied
== RL_HARD
|| implied
== RL_FUZZY
)
1102 if (custom_handle_variable
) {
1103 rl
= custom_handle_variable(expr
);
1108 if (get_implied_return(expr
, &rl
))
1110 return db_return_vals(expr
);
1113 static struct range_list
*handle_cast(struct expression
*expr
, int implied
, int *recurse_cnt
)
1115 struct range_list
*rl
;
1116 struct symbol
*type
;
1118 type
= get_type(expr
);
1119 rl
= _get_rl(expr
->cast_expression
, implied
, recurse_cnt
);
1121 return cast_rl(type
, rl
);
1122 if (implied
== RL_ABSOLUTE
|| implied
== RL_REAL_ABSOLUTE
)
1123 return alloc_whole_rl(type
);
1124 if (implied
== RL_IMPLIED
&& type
&&
1125 type_bits(type
) > 0 && type_bits(type
) < 32)
1126 return alloc_whole_rl(type
);
1130 static struct range_list
*_get_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
1132 struct range_list
*rl
;
1133 struct symbol
*type
;
1136 type
= get_type(expr
);
1137 expr
= strip_parens(expr
);
1141 if (++(*recurse_cnt
) >= 200)
1144 switch(expr
->type
) {
1146 case EXPR_FORCE_CAST
:
1147 case EXPR_IMPLIED_CAST
:
1148 rl
= handle_cast(expr
, implied
, recurse_cnt
);
1152 expr
= strip_expr(expr
);
1156 switch (expr
->type
) {
1158 sval
= sval_from_val(expr
, expr
->value
);
1159 rl
= alloc_rl(sval
, sval
);
1162 rl
= handle_preop_rl(expr
, implied
, recurse_cnt
);
1165 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
1168 rl
= handle_binop_rl(expr
, implied
, recurse_cnt
);
1171 rl
= handle_comparison_rl(expr
, implied
, recurse_cnt
);
1174 rl
= handle_logical_rl(expr
, implied
, recurse_cnt
);
1176 case EXPR_PTRSIZEOF
:
1178 sval
= handle_sizeof(expr
);
1179 rl
= alloc_rl(sval
, sval
);
1182 case EXPR_CONDITIONAL
:
1183 rl
= handle_conditional_rl(expr
, implied
, recurse_cnt
);
1186 rl
= handle_call_rl(expr
, implied
, recurse_cnt
);
1189 rl
= handle_variable(expr
, implied
, recurse_cnt
);
1195 if (type
&& (implied
== RL_ABSOLUTE
|| implied
== RL_REAL_ABSOLUTE
))
1196 return alloc_whole_rl(type
);
1201 struct expression
*expr
;
1202 struct range_list
*rl
;
1203 } cached_results
[24];
1204 static int cache_idx
;
1206 void clear_math_cache(void)
1208 memset(cached_results
, 0, sizeof(cached_results
));
1211 /* returns 1 if it can get a value literal or else returns 0 */
1212 int get_value(struct expression
*expr
, sval_t
*sval
)
1214 struct range_list
*(*orig_custom_fn
)(struct expression
*expr
);
1215 struct range_list
*rl
;
1216 int recurse_cnt
= 0;
1221 * This only handles RL_EXACT because other expr statements can be
1222 * different at different points. Like the list iterator, for example.
1224 for (i
= 0; i
< ARRAY_SIZE(cached_results
); i
++) {
1225 if (expr
== cached_results
[i
].expr
)
1226 return rl_to_sval(cached_results
[i
].rl
, sval
);
1229 orig_custom_fn
= custom_handle_variable
;
1230 custom_handle_variable
= NULL
;
1231 rl
= _get_rl(expr
, RL_EXACT
, &recurse_cnt
);
1232 if (!rl_to_sval(rl
, &tmp
))
1234 custom_handle_variable
= orig_custom_fn
;
1236 cached_results
[cache_idx
].expr
= expr
;
1237 cached_results
[cache_idx
].rl
= rl
;
1238 cache_idx
= (cache_idx
+ 1) % ARRAY_SIZE(cached_results
);
1247 static int get_implied_value_internal(struct expression
*expr
, sval_t
*sval
, int *recurse_cnt
)
1249 struct range_list
*rl
;
1251 rl
= _get_rl(expr
, RL_IMPLIED
, recurse_cnt
);
1252 if (!rl_to_sval(rl
, sval
))
1257 int get_implied_value(struct expression
*expr
, sval_t
*sval
)
1259 struct range_list
*rl
;
1260 int recurse_cnt
= 0;
1262 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1263 if (!rl_to_sval(rl
, sval
))
1268 int get_implied_min(struct expression
*expr
, sval_t
*sval
)
1270 struct range_list
*rl
;
1271 int recurse_cnt
= 0;
1273 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1280 int get_implied_max(struct expression
*expr
, sval_t
*sval
)
1282 struct range_list
*rl
;
1283 int recurse_cnt
= 0;
1285 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1292 int get_implied_rl(struct expression
*expr
, struct range_list
**rl
)
1294 int recurse_cnt
= 0;
1296 *rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1302 static int get_absolute_rl_internal(struct expression
*expr
, struct range_list
**rl
, int *recurse_cnt
)
1304 *rl
= _get_rl(expr
, RL_ABSOLUTE
, recurse_cnt
);
1306 *rl
= alloc_whole_rl(get_type(expr
));
1310 int get_absolute_rl(struct expression
*expr
, struct range_list
**rl
)
1312 int recurse_cnt
= 0;
1314 *rl
= _get_rl(expr
, RL_ABSOLUTE
, &recurse_cnt
);
1316 *rl
= alloc_whole_rl(get_type(expr
));
1320 int get_real_absolute_rl(struct expression
*expr
, struct range_list
**rl
)
1322 int recurse_cnt
= 0;
1324 *rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1326 *rl
= alloc_whole_rl(get_type(expr
));
1330 int custom_get_absolute_rl(struct expression
*expr
,
1331 struct range_list
*(*fn
)(struct expression
*expr
),
1332 struct range_list
**rl
)
1334 int recurse_cnt
= 0;
1337 custom_handle_variable
= fn
;
1338 *rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1339 custom_handle_variable
= NULL
;
1343 int get_implied_rl_var_sym(const char *var
, struct symbol
*sym
, struct range_list
**rl
)
1345 struct smatch_state
*state
;
1347 state
= get_state(SMATCH_EXTRA
, var
, sym
);
1348 *rl
= estate_rl(state
);
1354 int get_hard_max(struct expression
*expr
, sval_t
*sval
)
1356 struct range_list
*rl
;
1357 int recurse_cnt
= 0;
1359 rl
= _get_rl(expr
, RL_HARD
, &recurse_cnt
);
1366 int get_fuzzy_min(struct expression
*expr
, sval_t
*sval
)
1368 struct range_list
*rl
;
1370 int recurse_cnt
= 0;
1372 rl
= _get_rl(expr
, RL_FUZZY
, &recurse_cnt
);
1376 if (sval_is_negative(tmp
) && sval_is_min(tmp
))
1382 int get_fuzzy_max(struct expression
*expr
, sval_t
*sval
)
1384 struct range_list
*rl
;
1386 int recurse_cnt
= 0;
1388 rl
= _get_rl(expr
, RL_FUZZY
, &recurse_cnt
);
1392 if (max
.uvalue
> INT_MAX
- 10000)
1398 int get_absolute_min(struct expression
*expr
, sval_t
*sval
)
1400 struct range_list
*rl
;
1401 struct symbol
*type
;
1402 int recurse_cnt
= 0;
1404 type
= get_type(expr
);
1406 type
= &llong_ctype
; // FIXME: this is wrong but places assume get type can't fail.
1407 rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1411 *sval
= sval_type_min(type
);
1413 if (sval_cmp(*sval
, sval_type_min(type
)) < 0)
1414 *sval
= sval_type_min(type
);
1418 int get_absolute_max(struct expression
*expr
, sval_t
*sval
)
1420 struct range_list
*rl
;
1421 struct symbol
*type
;
1422 int recurse_cnt
= 0;
1424 type
= get_type(expr
);
1426 type
= &llong_ctype
;
1427 rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1431 *sval
= sval_type_max(type
);
1433 if (sval_cmp(sval_type_max(type
), *sval
) < 0)
1434 *sval
= sval_type_max(type
);
1438 int known_condition_true(struct expression
*expr
)
1445 if (get_value(expr
, &tmp
) && tmp
.value
)
1451 int known_condition_false(struct expression
*expr
)
1462 int implied_condition_true(struct expression
*expr
)
1469 if (known_condition_true(expr
))
1471 if (get_implied_value(expr
, &tmp
) && tmp
.value
)
1474 if (expr
->type
== EXPR_POSTOP
)
1475 return implied_condition_true(expr
->unop
);
1477 if (expr
->type
== EXPR_PREOP
&& expr
->op
== SPECIAL_DECREMENT
)
1478 return implied_not_equal(expr
->unop
, 1);
1479 if (expr
->type
== EXPR_PREOP
&& expr
->op
== SPECIAL_INCREMENT
)
1480 return implied_not_equal(expr
->unop
, -1);
1482 expr
= strip_expr(expr
);
1483 switch (expr
->type
) {
1485 if (do_comparison(expr
) == 1)
1489 if (expr
->op
== '!') {
1490 if (implied_condition_false(expr
->unop
))
1496 if (implied_not_equal(expr
, 0) == 1)
1503 int implied_condition_false(struct expression
*expr
)
1505 struct expression
*tmp
;
1511 if (known_condition_false(expr
))
1514 switch (expr
->type
) {
1516 if (do_comparison(expr
) == 2)
1519 if (expr
->op
== '!') {
1520 if (implied_condition_true(expr
->unop
))
1524 tmp
= strip_expr(expr
);
1526 return implied_condition_false(tmp
);
1529 if (get_implied_value(expr
, &sval
) && sval
.value
== 0)
1536 int can_integer_overflow(struct symbol
*type
, struct expression
*expr
)
1539 sval_t lmax
, rmax
, res
;
1544 expr
= strip_expr(expr
);
1546 if (expr
->type
== EXPR_ASSIGNMENT
) {
1548 case SPECIAL_MUL_ASSIGN
:
1551 case SPECIAL_ADD_ASSIGN
:
1554 case SPECIAL_SHL_ASSIGN
:
1555 op
= SPECIAL_LEFTSHIFT
;
1560 } else if (expr
->type
== EXPR_BINOP
) {
1561 if (expr
->op
!= '*' && expr
->op
!= '+' && expr
->op
!= SPECIAL_LEFTSHIFT
)
1568 get_absolute_max(expr
->left
, &lmax
);
1569 get_absolute_max(expr
->right
, &rmax
);
1571 if (sval_binop_overflows(lmax
, op
, rmax
))
1574 res
= sval_binop(lmax
, op
, rmax
);
1575 if (sval_cmp(res
, sval_type_max(type
)) > 0)