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
;
92 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
94 if (get_address_rl(expr
, &rl
))
96 return alloc_rl(valid_ptr_min_sval
, valid_ptr_max_sval
);
99 static struct range_list
*handle_negate_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
101 if (known_condition_true(expr
->unop
))
103 if (known_condition_false(expr
->unop
))
106 if (implied
== RL_EXACT
)
109 if (implied_condition_true(expr
->unop
))
111 if (implied_condition_false(expr
->unop
))
113 return alloc_rl(zero
, one
);
116 static struct range_list
*handle_bitwise_negate(struct expression
*expr
, int implied
, int *recurse_cnt
)
118 struct range_list
*rl
;
121 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
122 if (!rl_to_sval(rl
, &sval
))
124 sval
= sval_preop(sval
, '~');
125 sval_cast(get_type(expr
->unop
), sval
);
126 return alloc_rl(sval
, sval
);
129 static struct range_list
*handle_minus_preop(struct expression
*expr
, int implied
, int *recurse_cnt
)
131 struct range_list
*rl
;
134 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
135 min
= sval_preop(rl_max(rl
), '-');
136 max
= sval_preop(rl_min(rl
), '-');
137 return alloc_rl(min
, max
);
140 static struct range_list
*handle_preop_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
144 return handle_ampersand_rl(expr
, implied
, recurse_cnt
);
146 return handle_negate_rl(expr
, implied
, recurse_cnt
);
148 return handle_bitwise_negate(expr
, implied
, recurse_cnt
);
150 return handle_minus_preop(expr
, implied
, recurse_cnt
);
152 return handle_variable(expr
, implied
, recurse_cnt
);
154 return handle_expression_statement_rl(expr
, implied
, recurse_cnt
);
160 static struct range_list
*handle_divide_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
162 struct range_list
*left_rl
, *right_rl
;
165 type
= get_type(expr
);
167 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
168 left_rl
= cast_rl(type
, left_rl
);
169 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
170 right_rl
= cast_rl(type
, right_rl
);
172 if (!left_rl
|| !right_rl
)
175 if (implied
!= RL_REAL_ABSOLUTE
) {
176 if (is_whole_rl(left_rl
) || is_whole_rl(right_rl
))
180 return rl_binop(left_rl
, '/', right_rl
);
183 static int handle_offset_subtraction(struct expression
*expr
)
185 struct expression
*left
, *right
;
186 struct symbol
*left_sym
, *right_sym
;
188 int left_offset
, right_offset
;
190 type
= get_type(expr
);
191 if (!type
|| type
->type
!= SYM_PTR
)
193 type
= get_real_base_type(type
);
194 if (!type
|| (type_bits(type
) != 8 && (type
!= &void_ctype
)))
197 left
= strip_expr(expr
->left
);
198 right
= strip_expr(expr
->right
);
200 if (left
->type
!= EXPR_PREOP
|| left
->op
!= '&')
202 left
= strip_expr(left
->unop
);
204 left_sym
= expr_to_sym(left
);
205 right_sym
= expr_to_sym(right
);
206 if (!left_sym
|| left_sym
!= right_sym
)
209 left_offset
= get_member_offset_from_deref(left
);
210 if (right
->type
== EXPR_SYMBOL
)
213 if (right
->type
!= EXPR_PREOP
|| right
->op
!= '&')
215 right
= strip_expr(right
->unop
);
216 right_offset
= get_member_offset_from_deref(right
);
218 if (left_offset
< 0 || right_offset
< 0)
221 return left_offset
- right_offset
;
224 static struct range_list
*handle_subtract_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
227 struct range_list
*left_orig
, *right_orig
;
228 struct range_list
*left_rl
, *right_rl
;
229 sval_t max
, min
, tmp
;
233 type
= get_type(expr
);
235 offset
= handle_offset_subtraction(expr
);
240 return alloc_rl(tmp
, tmp
);
243 comparison
= get_comparison(expr
->left
, expr
->right
);
245 left_orig
= _get_rl(expr
->left
, implied
, recurse_cnt
);
246 left_rl
= cast_rl(type
, left_orig
);
247 right_orig
= _get_rl(expr
->right
, implied
, recurse_cnt
);
248 right_rl
= cast_rl(type
, right_orig
);
250 if ((!left_rl
|| !right_rl
) &&
251 (implied
== RL_EXACT
|| implied
== RL_HARD
|| implied
== RL_FUZZY
))
255 left_rl
= alloc_whole_rl(type
);
257 right_rl
= alloc_whole_rl(type
);
259 /* negative values complicate everything fix this later */
260 if (sval_is_negative(rl_min(right_rl
)))
262 max
= rl_max(left_rl
);
263 min
= sval_type_min(type
);
265 switch (comparison
) {
267 case SPECIAL_UNSIGNED_GT
:
268 min
= sval_type_val(type
, 1);
269 max
= rl_max(left_rl
);
272 case SPECIAL_UNSIGNED_GTE
:
273 min
= sval_type_val(type
, 0);
274 max
= rl_max(left_rl
);
277 min
= sval_type_val(type
, 0);
278 max
= sval_type_val(type
, 0);
281 case SPECIAL_UNSIGNED_LT
:
282 max
= sval_type_val(type
, -1);
285 case SPECIAL_UNSIGNED_LTE
:
286 max
= sval_type_val(type
, 0);
289 if (!left_orig
|| !right_orig
)
291 return rl_binop(left_rl
, '-', right_rl
);
294 if (!sval_binop_overflows(rl_min(left_rl
), '-', rl_max(right_rl
))) {
295 tmp
= sval_binop(rl_min(left_rl
), '-', rl_max(right_rl
));
296 if (sval_cmp(tmp
, min
) > 0)
300 if (!sval_is_max(rl_max(left_rl
))) {
301 tmp
= sval_binop(rl_max(left_rl
), '-', rl_min(right_rl
));
302 if (sval_cmp(tmp
, max
) < 0)
306 if (sval_is_min(min
) && sval_is_max(max
))
309 return cast_rl(type
, alloc_rl(min
, max
));
312 static struct range_list
*handle_mod_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
314 struct range_list
*rl
;
315 sval_t left
, right
, sval
;
317 if (implied
== RL_EXACT
) {
318 if (!get_implied_value(expr
->right
, &right
))
320 if (!get_implied_value(expr
->left
, &left
))
322 sval
= sval_binop(left
, '%', right
);
323 return alloc_rl(sval
, sval
);
325 /* if we can't figure out the right side it's probably hopeless */
326 if (!get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
329 right
= sval_cast(get_type(expr
), right
);
332 rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
333 if (rl
&& rl_max(rl
).uvalue
< right
.uvalue
)
334 right
.uvalue
= rl_max(rl
).uvalue
;
336 return alloc_rl(sval_cast(right
.type
, zero
), right
);
339 static sval_t
sval_lowest_set_bit(sval_t sval
)
344 for (i
= 0; i
< 64; i
++) {
345 if (sval
.uvalue
& 1ULL << i
) {
348 sval
.uvalue
&= ~(1ULL << i
);
354 static struct range_list
*handle_bitwise_AND(struct expression
*expr
, int implied
, int *recurse_cnt
)
357 struct range_list
*left_rl
, *right_rl
;
361 if (implied
!= RL_IMPLIED
&& implied
!= RL_ABSOLUTE
&& implied
!= RL_REAL_ABSOLUTE
)
364 type
= get_type(expr
);
366 if (get_implied_value_internal(expr
->left
, &known
, recurse_cnt
)) {
369 min
= sval_lowest_set_bit(known
);
370 left_rl
= alloc_rl(min
, known
);
371 left_rl
= cast_rl(type
, left_rl
);
372 add_range(&left_rl
, sval_type_val(type
, 0), sval_type_val(type
, 0));
374 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
376 left_rl
= cast_rl(type
, left_rl
);
377 left_rl
= alloc_rl(sval_type_val(type
, 0), rl_max(left_rl
));
379 if (implied
== RL_HARD
)
381 left_rl
= alloc_whole_rl(type
);
385 new_recurse
= *recurse_cnt
;
386 if (*recurse_cnt
>= 200)
387 new_recurse
= 100; /* Let's try super hard to get the mask */
388 if (get_implied_value_internal(expr
->right
, &known
, &new_recurse
)) {
389 sval_t min
, left_max
, mod
;
391 *recurse_cnt
= new_recurse
;
393 min
= sval_lowest_set_bit(known
);
394 right_rl
= alloc_rl(min
, known
);
395 right_rl
= cast_rl(type
, right_rl
);
396 add_range(&right_rl
, sval_type_val(type
, 0), sval_type_val(type
, 0));
398 if (min
.value
!= 0) {
399 left_max
= rl_max(left_rl
);
400 mod
= sval_binop(left_max
, '%', min
);
402 left_max
= sval_binop(left_max
, '-', mod
);
404 if (left_max
.value
> 0 && sval_cmp(left_max
, rl_max(left_rl
)) < 0)
405 left_rl
= remove_range(left_rl
, left_max
, rl_max(left_rl
));
409 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
411 right_rl
= cast_rl(type
, right_rl
);
412 right_rl
= alloc_rl(sval_type_val(type
, 0), rl_max(right_rl
));
414 if (implied
== RL_HARD
)
416 right_rl
= alloc_whole_rl(type
);
420 return rl_intersection(left_rl
, right_rl
);
423 static struct range_list
*use_rl_binop(struct expression
*expr
, int implied
, int *recurse_cnt
)
426 struct range_list
*left_rl
, *right_rl
;
428 if (implied
!= RL_IMPLIED
&& implied
!= RL_ABSOLUTE
&& implied
!= RL_REAL_ABSOLUTE
)
431 type
= get_type(expr
);
433 get_absolute_rl_internal(expr
->left
, &left_rl
, recurse_cnt
);
434 get_absolute_rl_internal(expr
->right
, &right_rl
, recurse_cnt
);
435 left_rl
= cast_rl(type
, left_rl
);
436 right_rl
= cast_rl(type
, right_rl
);
437 if (!left_rl
|| !right_rl
)
440 return rl_binop(left_rl
, expr
->op
, right_rl
);
443 static struct range_list
*handle_right_shift(struct expression
*expr
, int implied
, int *recurse_cnt
)
445 struct range_list
*left_rl
;
449 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
452 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
454 max
= rl_max(left_rl
);
455 min
= rl_min(left_rl
);
457 if (implied
== RL_FUZZY
)
459 max
= sval_type_max(get_type(expr
->left
));
460 min
= sval_type_val(get_type(expr
->left
), 0);
463 if (get_implied_value_internal(expr
->right
, &right
, recurse_cnt
)) {
464 min
= sval_binop(min
, SPECIAL_RIGHTSHIFT
, right
);
465 max
= sval_binop(max
, SPECIAL_RIGHTSHIFT
, right
);
466 } else if (!sval_is_negative(min
)) {
468 max
= sval_type_max(max
.type
);
473 return alloc_rl(min
, max
);
476 static struct range_list
*handle_left_shift(struct expression
*expr
, int implied
, int *recurse_cnt
)
478 struct range_list
*left_rl
, *res
;
483 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
485 /* this is hopeless without the right side */
486 if (!get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
488 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
490 max
= rl_max(left_rl
);
491 min
= rl_min(left_rl
);
492 if (min
.value
== 0) {
497 if (implied
== RL_FUZZY
)
499 max
= sval_type_max(get_type(expr
->left
));
500 min
= sval_type_val(get_type(expr
->left
), 1);
504 max
= sval_binop(max
, SPECIAL_LEFTSHIFT
, right
);
505 min
= sval_binop(min
, SPECIAL_LEFTSHIFT
, right
);
506 res
= alloc_rl(min
, max
);
508 res
= rl_union(res
, rl_zero());
512 static struct range_list
*handle_known_binop(struct expression
*expr
)
516 if (!get_value(expr
->left
, &left
))
518 if (!get_value(expr
->right
, &right
))
520 left
= sval_binop(left
, expr
->op
, right
);
521 return alloc_rl(left
, left
);
524 static int has_actual_ranges(struct range_list
*rl
)
526 struct data_range
*tmp
;
528 FOR_EACH_PTR(rl
, tmp
) {
529 if (sval_cmp(tmp
->min
, tmp
->max
) != 0)
531 } END_FOR_EACH_PTR(tmp
);
535 static struct range_list
*handle_implied_binop(struct range_list
*left_rl
, int op
, struct range_list
*right_rl
)
537 struct range_list
*res_rl
;
538 struct data_range
*left_drange
, *right_drange
;
541 if (!left_rl
|| !right_rl
)
543 if (has_actual_ranges(left_rl
))
545 if (has_actual_ranges(right_rl
))
548 if (ptr_list_size((struct ptr_list
*)left_rl
) * ptr_list_size((struct ptr_list
*)right_rl
) > 20)
553 FOR_EACH_PTR(left_rl
, left_drange
) {
554 FOR_EACH_PTR(right_rl
, right_drange
) {
555 if ((op
== '%' || op
== '/') &&
556 right_drange
->min
.value
== 0)
558 res
= sval_binop(left_drange
->min
, op
, right_drange
->min
);
559 add_range(&res_rl
, res
, res
);
560 } END_FOR_EACH_PTR(right_drange
);
561 } END_FOR_EACH_PTR(left_drange
);
566 static struct range_list
*handle_binop_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
568 struct smatch_state
*state
;
570 struct range_list
*left_rl
, *right_rl
, *rl
;
573 rl
= handle_known_binop(expr
);
576 if (implied
== RL_EXACT
)
579 if (custom_handle_variable
) {
580 rl
= custom_handle_variable(expr
);
585 state
= get_extra_state(expr
);
586 if (state
&& !is_whole_rl(estate_rl(state
))) {
587 if (implied
!= RL_HARD
|| estate_has_hard_max(state
))
588 return clone_rl(estate_rl(state
));
591 type
= get_type(expr
);
592 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
593 left_rl
= cast_rl(type
, left_rl
);
594 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
595 right_rl
= cast_rl(type
, right_rl
);
597 if (!left_rl
&& !right_rl
)
600 rl
= handle_implied_binop(left_rl
, expr
->op
, right_rl
);
606 return handle_mod_rl(expr
, implied
, recurse_cnt
);
608 return handle_bitwise_AND(expr
, implied
, recurse_cnt
);
611 return use_rl_binop(expr
, implied
, recurse_cnt
);
612 case SPECIAL_RIGHTSHIFT
:
613 return handle_right_shift(expr
, implied
, recurse_cnt
);
614 case SPECIAL_LEFTSHIFT
:
615 return handle_left_shift(expr
, implied
, recurse_cnt
);
617 return handle_subtract_rl(expr
, implied
, recurse_cnt
);
619 return handle_divide_rl(expr
, implied
, recurse_cnt
);
622 if (!left_rl
|| !right_rl
)
625 if (sval_binop_overflows(rl_min(left_rl
), expr
->op
, rl_min(right_rl
)))
627 if (sval_binop_overflows(rl_max(left_rl
), expr
->op
, rl_max(right_rl
)))
630 min
= sval_binop(rl_min(left_rl
), expr
->op
, rl_min(right_rl
));
631 max
= sval_binop(rl_max(left_rl
), expr
->op
, rl_max(right_rl
));
633 return alloc_rl(min
, max
);
636 static int do_comparison(struct expression
*expr
)
638 struct range_list
*left_ranges
= NULL
;
639 struct range_list
*right_ranges
= NULL
;
640 int poss_true
, poss_false
;
643 type
= get_type(expr
);
644 get_absolute_rl(expr
->left
, &left_ranges
);
645 get_absolute_rl(expr
->right
, &right_ranges
);
647 left_ranges
= cast_rl(type
, left_ranges
);
648 right_ranges
= cast_rl(type
, right_ranges
);
650 poss_true
= possibly_true_rl(left_ranges
, expr
->op
, right_ranges
);
651 poss_false
= possibly_false_rl(left_ranges
, expr
->op
, right_ranges
);
653 if (!poss_true
&& !poss_false
)
655 if (poss_true
&& !poss_false
)
657 if (!poss_true
&& poss_false
)
662 static struct range_list
*handle_comparison_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
667 if (expr
->op
== SPECIAL_EQUAL
&& expr
->left
->type
== EXPR_TYPE
) {
668 struct symbol
*left
, *right
;
670 left
= get_real_base_type(expr
->left
->symbol
);
671 right
= get_real_base_type(expr
->left
->symbol
);
677 if (get_value(expr
->left
, &left
) && get_value(expr
->right
, &right
)) {
678 struct data_range tmp_left
, tmp_right
;
682 tmp_right
.min
= right
;
683 tmp_right
.max
= right
;
684 if (true_comparison_range(&tmp_left
, expr
->op
, &tmp_right
))
689 if (implied
== RL_EXACT
)
692 res
= do_comparison(expr
);
698 return alloc_rl(zero
, one
);
701 static struct range_list
*handle_logical_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
707 if (implied
== RL_EXACT
) {
708 if (get_value(expr
->left
, &left
))
710 if (get_value(expr
->right
, &right
))
713 if (get_implied_value_internal(expr
->left
, &left
, recurse_cnt
))
715 if (get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
720 case SPECIAL_LOGICAL_OR
:
721 if (left_known
&& left
.value
)
723 if (right_known
&& right
.value
)
725 if (left_known
&& right_known
)
728 case SPECIAL_LOGICAL_AND
:
729 if (left_known
&& right_known
) {
730 if (left
.value
&& right
.value
)
739 if (implied
== RL_EXACT
)
742 return alloc_rl(zero
, one
);
745 static struct range_list
*handle_conditional_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
747 struct range_list
*true_rl
, *false_rl
;
749 int final_pass_orig
= final_pass
;
751 if (known_condition_true(expr
->conditional
))
752 return _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
753 if (known_condition_false(expr
->conditional
))
754 return _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
756 if (implied
== RL_EXACT
)
759 if (implied_condition_true(expr
->conditional
))
760 return _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
761 if (implied_condition_false(expr
->conditional
))
762 return _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
765 /* this becomes a problem with deeply nested conditional statements */
769 type
= get_type(expr
);
771 __push_fake_cur_stree();
773 __split_whole_condition(expr
->conditional
);
774 true_rl
= _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
775 __push_true_states();
776 __use_false_states();
777 false_rl
= _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
778 __merge_true_states();
779 __free_fake_cur_stree();
780 final_pass
= final_pass_orig
;
782 if (!true_rl
|| !false_rl
)
784 true_rl
= cast_rl(type
, true_rl
);
785 false_rl
= cast_rl(type
, false_rl
);
787 return rl_union(true_rl
, false_rl
);
790 static int get_fuzzy_max_helper(struct expression
*expr
, sval_t
*max
)
792 struct smatch_state
*state
;
795 if (get_hard_max(expr
, &sval
)) {
800 state
= get_extra_state(expr
);
801 if (!state
|| !estate_has_fuzzy_max(state
))
803 *max
= sval_cast(get_type(expr
), estate_get_fuzzy_max(state
));
807 static int get_fuzzy_min_helper(struct expression
*expr
, sval_t
*min
)
809 struct smatch_state
*state
;
812 state
= get_extra_state(expr
);
813 if (!state
|| !estate_rl(state
))
816 sval
= estate_min(state
);
817 if (sval_is_negative(sval
) && sval_is_min(sval
))
820 if (sval_is_max(sval
))
823 *min
= sval_cast(get_type(expr
), sval
);
827 int get_const_value(struct expression
*expr
, sval_t
*sval
)
832 if (expr
->type
!= EXPR_SYMBOL
|| !expr
->symbol
)
835 if (!(sym
->ctype
.modifiers
& MOD_CONST
))
837 if (get_value(sym
->initializer
, &right
)) {
838 *sval
= sval_cast(get_type(expr
), right
);
844 struct range_list
*var_to_absolute_rl(struct expression
*expr
)
846 struct smatch_state
*state
;
847 struct range_list
*rl
;
849 state
= get_extra_state(expr
);
850 if (!state
|| is_whole_rl(estate_rl(state
))) {
851 state
= get_real_absolute_state(expr
);
852 if (state
&& state
->data
&& !estate_is_whole(state
))
853 return clone_rl(estate_rl(state
));
854 if (get_local_rl(expr
, &rl
) && !is_whole_rl(rl
))
856 if (get_db_type_rl(expr
, &rl
) && !is_whole_rl(rl
))
858 return alloc_whole_rl(get_type(expr
));
860 /* err on the side of saying things are possible */
861 if (!estate_rl(state
))
862 return alloc_whole_rl(get_type(expr
));
863 return clone_rl(estate_rl(state
));
866 static struct range_list
*handle_variable(struct expression
*expr
, int implied
, int *recurse_cnt
)
868 struct smatch_state
*state
;
869 struct range_list
*rl
;
870 sval_t sval
, min
, max
;
873 if (get_const_value(expr
, &sval
))
874 return alloc_rl(sval
, sval
);
876 if (custom_handle_variable
) {
877 rl
= custom_handle_variable(expr
);
879 return var_to_absolute_rl(expr
);
883 if (implied
== RL_EXACT
)
886 type
= get_type(expr
);
887 if (type
&& type
->type
== SYM_FN
)
888 return alloc_rl(fn_ptr_min
, fn_ptr_max
);
894 state
= get_extra_state(expr
);
895 if (!state
|| !state
->data
) {
896 if (implied
== RL_HARD
)
898 if (get_local_rl(expr
, &rl
))
900 if (get_db_type_rl(expr
, &rl
))
904 if (implied
== RL_HARD
&& !estate_has_hard_max(state
))
906 return clone_rl(estate_rl(state
));
907 case RL_REAL_ABSOLUTE
: {
908 struct smatch_state
*abs_state
;
910 state
= get_extra_state(expr
);
911 abs_state
= get_real_absolute_state(expr
);
913 if (estate_rl(state
) && estate_rl(abs_state
)) {
914 return clone_rl(rl_intersection(estate_rl(state
),
915 estate_rl(abs_state
)));
916 } else if (estate_rl(state
)) {
917 return clone_rl(estate_rl(state
));
918 } else if (estate_is_empty(state
)) {
920 * FIXME: we don't handle empty extra states correctly.
922 * The real abs rl is supposed to be filtered by the
923 * extra state if there is one. We don't bother keeping
924 * the abs state in sync all the time because we know it
925 * will be filtered later.
927 * It's not totally obvious to me how they should be
928 * handled. Perhaps we should take the whole rl and
929 * filter by the imaginary states. Perhaps we should
930 * just go with the empty state.
932 * Anyway what we currently do is return NULL here and
933 * that gets translated into the whole range in
934 * get_real_absolute_rl().
938 } else if (estate_rl(abs_state
)) {
939 return clone_rl(estate_rl(abs_state
));
942 if (get_local_rl(expr
, &rl
))
944 if (get_db_type_rl(expr
, &rl
))
949 if (!get_fuzzy_min_helper(expr
, &min
))
950 min
= sval_type_min(get_type(expr
));
951 if (!get_fuzzy_max_helper(expr
, &max
))
953 /* fuzzy ranges are often inverted */
954 if (sval_cmp(min
, max
) > 0) {
959 return alloc_rl(min
, max
);
964 static sval_t
handle_sizeof(struct expression
*expr
)
969 ret
= sval_blank(expr
);
970 sym
= expr
->cast_type
;
972 sym
= evaluate_expression(expr
->cast_expression
);
974 __silence_warnings_for_stmt
= true;
979 * Expressions of restricted types will possibly get
980 * promoted - check that here. I'm not sure how this works,
981 * the problem is that sizeof(le16) shouldn't be promoted and
982 * the original code did that... Let's if zero this out and
986 if (is_restricted_type(sym
)) {
987 if (type_bits(sym
) < bits_in_int
)
991 if (is_fouled_type(sym
))
994 examine_symbol_type(sym
);
996 ret
.type
= size_t_ctype
;
997 if (type_bits(sym
) <= 0) /* sizeof(void) */ {
998 if (get_real_base_type(sym
) == &void_ctype
)
1003 ret
.value
= type_bytes(sym
);
1008 static struct range_list
*handle_strlen(struct expression
*expr
, int implied
, int *recurse_cnt
)
1010 struct range_list
*rl
;
1011 struct expression
*arg
;
1012 sval_t sval
= { .type
= &ulong_ctype
};
1014 if (implied
== RL_EXACT
)
1017 arg
= get_argument_from_call_expr(expr
->args
, 0);
1020 if (arg
->type
== EXPR_STRING
) {
1021 sval
.value
= arg
->string
->length
- 1;
1022 return alloc_rl(sval
, sval
);
1025 if (implied
== RL_HARD
|| implied
== RL_FUZZY
)
1028 if (get_implied_return(expr
, &rl
))
1034 static struct range_list
*handle_builtin_constant_p(struct expression
*expr
, int implied
, int *recurse_cnt
)
1036 struct expression
*arg
;
1037 struct range_list
*rl
;
1040 arg
= get_argument_from_call_expr(expr
->args
, 0);
1041 rl
= _get_rl(arg
, RL_EXACT
, recurse_cnt
);
1042 if (rl_to_sval(rl
, &sval
))
1047 static struct range_list
*handle__builtin_choose_expr(struct expression
*expr
, int implied
, int *recurse_cnt
)
1049 struct expression
*const_expr
, *expr1
, *expr2
;
1052 const_expr
= get_argument_from_call_expr(expr
->args
, 0);
1053 expr1
= get_argument_from_call_expr(expr
->args
, 1);
1054 expr2
= get_argument_from_call_expr(expr
->args
, 2);
1056 if (!get_value(const_expr
, &sval
) || !expr1
|| !expr2
)
1059 return _get_rl(expr1
, implied
, recurse_cnt
);
1060 return _get_rl(expr2
, implied
, recurse_cnt
);
1063 static struct range_list
*handle_call_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
1065 struct range_list
*rl
;
1067 if (sym_name_is("__builtin_constant_p", expr
->fn
))
1068 return handle_builtin_constant_p(expr
, implied
, recurse_cnt
);
1070 if (sym_name_is("__builtin_choose_expr", expr
->fn
))
1071 return handle__builtin_choose_expr(expr
, implied
, recurse_cnt
);
1073 if (sym_name_is("__builtin_expect", expr
->fn
) ||
1074 sym_name_is("__builtin_bswap16", expr
->fn
) ||
1075 sym_name_is("__builtin_bswap32", expr
->fn
) ||
1076 sym_name_is("__builtin_bswap64", expr
->fn
)) {
1077 struct expression
*arg
;
1079 arg
= get_argument_from_call_expr(expr
->args
, 0);
1080 return _get_rl(arg
, implied
, recurse_cnt
);
1083 if (sym_name_is("strlen", expr
->fn
))
1084 return handle_strlen(expr
, implied
, recurse_cnt
);
1086 if (implied
== RL_EXACT
|| implied
== RL_HARD
|| implied
== RL_FUZZY
)
1089 if (custom_handle_variable
) {
1090 rl
= custom_handle_variable(expr
);
1095 if (get_implied_return(expr
, &rl
))
1097 return db_return_vals(expr
);
1100 static struct range_list
*handle_cast(struct expression
*expr
, int implied
, int *recurse_cnt
)
1102 struct range_list
*rl
;
1103 struct symbol
*type
;
1105 type
= get_type(expr
);
1106 rl
= _get_rl(expr
->cast_expression
, implied
, recurse_cnt
);
1108 return cast_rl(type
, rl
);
1109 if (implied
== RL_ABSOLUTE
|| implied
== RL_REAL_ABSOLUTE
)
1110 return alloc_whole_rl(type
);
1111 if (implied
== RL_IMPLIED
&& type
&&
1112 type_bits(type
) > 0 && type_bits(type
) < 32)
1113 return alloc_whole_rl(type
);
1117 static struct range_list
*_get_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
1119 struct range_list
*rl
;
1120 struct symbol
*type
;
1123 type
= get_type(expr
);
1124 expr
= strip_parens(expr
);
1128 if (++(*recurse_cnt
) >= 200)
1131 switch(expr
->type
) {
1133 case EXPR_FORCE_CAST
:
1134 case EXPR_IMPLIED_CAST
:
1135 rl
= handle_cast(expr
, implied
, recurse_cnt
);
1139 expr
= strip_expr(expr
);
1143 switch (expr
->type
) {
1145 sval
= sval_from_val(expr
, expr
->value
);
1146 rl
= alloc_rl(sval
, sval
);
1149 rl
= handle_preop_rl(expr
, implied
, recurse_cnt
);
1152 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
1155 rl
= handle_binop_rl(expr
, implied
, recurse_cnt
);
1158 rl
= handle_comparison_rl(expr
, implied
, recurse_cnt
);
1161 rl
= handle_logical_rl(expr
, implied
, recurse_cnt
);
1163 case EXPR_PTRSIZEOF
:
1165 sval
= handle_sizeof(expr
);
1166 rl
= alloc_rl(sval
, sval
);
1169 case EXPR_CONDITIONAL
:
1170 rl
= handle_conditional_rl(expr
, implied
, recurse_cnt
);
1173 rl
= handle_call_rl(expr
, implied
, recurse_cnt
);
1176 rl
= handle_variable(expr
, implied
, recurse_cnt
);
1182 if (type
&& (implied
== RL_ABSOLUTE
|| implied
== RL_REAL_ABSOLUTE
))
1183 return alloc_whole_rl(type
);
1188 struct expression
*expr
;
1189 struct range_list
*rl
;
1190 } cached_results
[24];
1191 static int cache_idx
;
1193 void clear_math_cache(void)
1195 memset(cached_results
, 0, sizeof(cached_results
));
1198 /* returns 1 if it can get a value literal or else returns 0 */
1199 int get_value(struct expression
*expr
, sval_t
*sval
)
1201 struct range_list
*(*orig_custom_fn
)(struct expression
*expr
);
1202 struct range_list
*rl
;
1203 int recurse_cnt
= 0;
1208 * This only handles RL_EXACT because other expr statements can be
1209 * different at different points. Like the list iterator, for example.
1211 for (i
= 0; i
< ARRAY_SIZE(cached_results
); i
++) {
1212 if (expr
== cached_results
[i
].expr
)
1213 return rl_to_sval(cached_results
[i
].rl
, sval
);
1216 orig_custom_fn
= custom_handle_variable
;
1217 custom_handle_variable
= NULL
;
1218 rl
= _get_rl(expr
, RL_EXACT
, &recurse_cnt
);
1219 if (!rl_to_sval(rl
, &tmp
))
1221 custom_handle_variable
= orig_custom_fn
;
1223 cached_results
[cache_idx
].expr
= expr
;
1224 cached_results
[cache_idx
].rl
= rl
;
1225 cache_idx
= (cache_idx
+ 1) % ARRAY_SIZE(cached_results
);
1234 static int get_implied_value_internal(struct expression
*expr
, sval_t
*sval
, int *recurse_cnt
)
1236 struct range_list
*rl
;
1238 rl
= _get_rl(expr
, RL_IMPLIED
, recurse_cnt
);
1239 if (!rl_to_sval(rl
, sval
))
1244 int get_implied_value(struct expression
*expr
, sval_t
*sval
)
1246 struct range_list
*rl
;
1247 int recurse_cnt
= 0;
1249 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1250 if (!rl_to_sval(rl
, sval
))
1255 int get_implied_min(struct expression
*expr
, sval_t
*sval
)
1257 struct range_list
*rl
;
1258 int recurse_cnt
= 0;
1260 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1267 int get_implied_max(struct expression
*expr
, sval_t
*sval
)
1269 struct range_list
*rl
;
1270 int recurse_cnt
= 0;
1272 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1279 int get_implied_rl(struct expression
*expr
, struct range_list
**rl
)
1281 int recurse_cnt
= 0;
1283 *rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1289 static int get_absolute_rl_internal(struct expression
*expr
, struct range_list
**rl
, int *recurse_cnt
)
1291 *rl
= _get_rl(expr
, RL_ABSOLUTE
, recurse_cnt
);
1293 *rl
= alloc_whole_rl(get_type(expr
));
1297 int get_absolute_rl(struct expression
*expr
, struct range_list
**rl
)
1299 int recurse_cnt
= 0;
1301 *rl
= _get_rl(expr
, RL_ABSOLUTE
, &recurse_cnt
);
1303 *rl
= alloc_whole_rl(get_type(expr
));
1307 int get_real_absolute_rl(struct expression
*expr
, struct range_list
**rl
)
1309 int recurse_cnt
= 0;
1311 *rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1313 *rl
= alloc_whole_rl(get_type(expr
));
1317 int custom_get_absolute_rl(struct expression
*expr
,
1318 struct range_list
*(*fn
)(struct expression
*expr
),
1319 struct range_list
**rl
)
1321 int recurse_cnt
= 0;
1324 custom_handle_variable
= fn
;
1325 *rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1326 custom_handle_variable
= NULL
;
1330 int get_implied_rl_var_sym(const char *var
, struct symbol
*sym
, struct range_list
**rl
)
1332 struct smatch_state
*state
;
1334 state
= get_state(SMATCH_EXTRA
, var
, sym
);
1335 *rl
= estate_rl(state
);
1341 int get_hard_max(struct expression
*expr
, sval_t
*sval
)
1343 struct range_list
*rl
;
1344 int recurse_cnt
= 0;
1346 rl
= _get_rl(expr
, RL_HARD
, &recurse_cnt
);
1353 int get_fuzzy_min(struct expression
*expr
, sval_t
*sval
)
1355 struct range_list
*rl
;
1357 int recurse_cnt
= 0;
1359 rl
= _get_rl(expr
, RL_FUZZY
, &recurse_cnt
);
1363 if (sval_is_negative(tmp
) && sval_is_min(tmp
))
1369 int get_fuzzy_max(struct expression
*expr
, sval_t
*sval
)
1371 struct range_list
*rl
;
1373 int recurse_cnt
= 0;
1375 rl
= _get_rl(expr
, RL_FUZZY
, &recurse_cnt
);
1379 if (max
.uvalue
> INT_MAX
- 10000)
1385 int get_absolute_min(struct expression
*expr
, sval_t
*sval
)
1387 struct range_list
*rl
;
1388 struct symbol
*type
;
1389 int recurse_cnt
= 0;
1391 type
= get_type(expr
);
1393 type
= &llong_ctype
; // FIXME: this is wrong but places assume get type can't fail.
1394 rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1398 *sval
= sval_type_min(type
);
1400 if (sval_cmp(*sval
, sval_type_min(type
)) < 0)
1401 *sval
= sval_type_min(type
);
1405 int get_absolute_max(struct expression
*expr
, sval_t
*sval
)
1407 struct range_list
*rl
;
1408 struct symbol
*type
;
1409 int recurse_cnt
= 0;
1411 type
= get_type(expr
);
1413 type
= &llong_ctype
;
1414 rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1418 *sval
= sval_type_max(type
);
1420 if (sval_cmp(sval_type_max(type
), *sval
) < 0)
1421 *sval
= sval_type_max(type
);
1425 int known_condition_true(struct expression
*expr
)
1432 if (get_value(expr
, &tmp
) && tmp
.value
)
1438 int known_condition_false(struct expression
*expr
)
1449 int implied_condition_true(struct expression
*expr
)
1456 if (known_condition_true(expr
))
1458 if (get_implied_value(expr
, &tmp
) && tmp
.value
)
1461 if (expr
->type
== EXPR_POSTOP
)
1462 return implied_condition_true(expr
->unop
);
1464 if (expr
->type
== EXPR_PREOP
&& expr
->op
== SPECIAL_DECREMENT
)
1465 return implied_not_equal(expr
->unop
, 1);
1466 if (expr
->type
== EXPR_PREOP
&& expr
->op
== SPECIAL_INCREMENT
)
1467 return implied_not_equal(expr
->unop
, -1);
1469 expr
= strip_expr(expr
);
1470 switch (expr
->type
) {
1472 if (do_comparison(expr
) == 1)
1476 if (expr
->op
== '!') {
1477 if (implied_condition_false(expr
->unop
))
1483 if (implied_not_equal(expr
, 0) == 1)
1490 int implied_condition_false(struct expression
*expr
)
1492 struct expression
*tmp
;
1498 if (known_condition_false(expr
))
1501 switch (expr
->type
) {
1503 if (do_comparison(expr
) == 2)
1506 if (expr
->op
== '!') {
1507 if (implied_condition_true(expr
->unop
))
1511 tmp
= strip_expr(expr
);
1513 return implied_condition_false(tmp
);
1516 if (get_implied_value(expr
, &sval
) && sval
.value
== 0)
1523 int can_integer_overflow(struct symbol
*type
, struct expression
*expr
)
1526 sval_t lmax
, rmax
, res
;
1531 expr
= strip_expr(expr
);
1533 if (expr
->type
== EXPR_ASSIGNMENT
) {
1535 case SPECIAL_MUL_ASSIGN
:
1538 case SPECIAL_ADD_ASSIGN
:
1541 case SPECIAL_SHL_ASSIGN
:
1542 op
= SPECIAL_LEFTSHIFT
;
1547 } else if (expr
->type
== EXPR_BINOP
) {
1548 if (expr
->op
!= '*' && expr
->op
!= '+' && expr
->op
!= SPECIAL_LEFTSHIFT
)
1555 get_absolute_max(expr
->left
, &lmax
);
1556 get_absolute_max(expr
->right
, &rmax
);
1558 if (sval_binop_overflows(lmax
, op
, rmax
))
1561 res
= sval_binop(lmax
, op
, rmax
);
1562 if (sval_cmp(res
, sval_type_max(type
)) > 0)