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 return alloc_rl(zero
, zero
);
38 struct range_list
*rl_one(void)
40 return alloc_rl(one
, one
);
52 static struct range_list
*last_stmt_rl(struct statement
*stmt
, int implied
, int *recurse_cnt
)
54 struct expression
*expr
;
59 stmt
= last_ptr_list((struct ptr_list
*)stmt
->stmts
);
60 if (stmt
->type
== STMT_LABEL
) {
61 if (stmt
->label_statement
&&
62 stmt
->label_statement
->type
== STMT_EXPRESSION
)
63 expr
= stmt
->label_statement
->expression
;
66 } else if (stmt
->type
== STMT_EXPRESSION
) {
67 expr
= stmt
->expression
;
71 return _get_rl(expr
, implied
, recurse_cnt
);
74 static struct range_list
*handle_expression_statement_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
76 return last_stmt_rl(get_expression_statement(expr
), implied
, recurse_cnt
);
79 static struct range_list
*handle_ampersand_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
81 struct range_list
*rl
;
83 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
85 if (get_address_rl(expr
, &rl
))
87 return alloc_rl(valid_ptr_min_sval
, valid_ptr_max_sval
);
90 static struct range_list
*handle_negate_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
92 if (known_condition_true(expr
->unop
))
94 if (known_condition_false(expr
->unop
))
97 if (implied
== RL_EXACT
)
100 if (implied_condition_true(expr
->unop
))
102 if (implied_condition_false(expr
->unop
))
104 return alloc_rl(zero
, one
);
107 static struct range_list
*handle_bitwise_negate(struct expression
*expr
, int implied
, int *recurse_cnt
)
109 struct range_list
*rl
;
112 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
113 if (!rl_to_sval(rl
, &sval
))
115 sval
= sval_preop(sval
, '~');
116 sval_cast(get_type(expr
->unop
), sval
);
117 return alloc_rl(sval
, sval
);
120 static struct range_list
*handle_minus_preop(struct expression
*expr
, int implied
, int *recurse_cnt
)
122 struct range_list
*rl
;
125 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
126 min
= sval_preop(rl_max(rl
), '-');
127 max
= sval_preop(rl_min(rl
), '-');
128 return alloc_rl(min
, max
);
131 static struct range_list
*handle_preop_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
135 return handle_ampersand_rl(expr
, implied
, recurse_cnt
);
137 return handle_negate_rl(expr
, implied
, recurse_cnt
);
139 return handle_bitwise_negate(expr
, implied
, recurse_cnt
);
141 return handle_minus_preop(expr
, implied
, recurse_cnt
);
143 return handle_variable(expr
, implied
, recurse_cnt
);
145 return handle_expression_statement_rl(expr
, implied
, recurse_cnt
);
151 static struct range_list
*handle_divide_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
153 struct range_list
*left_rl
, *right_rl
;
156 type
= get_type(expr
);
158 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
159 left_rl
= cast_rl(type
, left_rl
);
160 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
161 right_rl
= cast_rl(type
, right_rl
);
163 if (!left_rl
|| !right_rl
)
166 if (implied
!= RL_REAL_ABSOLUTE
) {
167 if (is_whole_rl(left_rl
) || is_whole_rl(right_rl
))
171 return rl_binop(left_rl
, '/', right_rl
);
174 static int handle_offset_subtraction(struct expression
*expr
)
176 struct expression
*left
, *right
;
177 struct symbol
*left_sym
, *right_sym
;
179 int left_offset
, right_offset
;
181 type
= get_type(expr
);
182 if (!type
|| type
->type
!= SYM_PTR
)
184 type
= get_real_base_type(type
);
185 if (!type
|| (type_bits(type
) != 8 && (type
!= &void_ctype
)))
188 left
= strip_expr(expr
->left
);
189 right
= strip_expr(expr
->right
);
191 if (left
->type
!= EXPR_PREOP
|| left
->op
!= '&')
193 left
= strip_expr(left
->unop
);
195 left_sym
= expr_to_sym(left
);
196 right_sym
= expr_to_sym(right
);
197 if (!left_sym
|| left_sym
!= right_sym
)
200 left_offset
= get_member_offset_from_deref(left
);
201 if (right
->type
== EXPR_SYMBOL
)
204 if (right
->type
!= EXPR_PREOP
|| right
->op
!= '&')
206 right
= strip_expr(right
->unop
);
207 right_offset
= get_member_offset_from_deref(right
);
209 if (left_offset
< 0 || right_offset
< 0)
212 return left_offset
- right_offset
;
215 static struct range_list
*handle_subtract_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
218 struct range_list
*left_orig
, *right_orig
;
219 struct range_list
*left_rl
, *right_rl
;
220 sval_t max
, min
, tmp
;
224 type
= get_type(expr
);
226 offset
= handle_offset_subtraction(expr
);
231 return alloc_rl(tmp
, tmp
);
234 comparison
= get_comparison(expr
->left
, expr
->right
);
236 left_orig
= _get_rl(expr
->left
, implied
, recurse_cnt
);
237 left_rl
= cast_rl(type
, left_orig
);
238 right_orig
= _get_rl(expr
->right
, implied
, recurse_cnt
);
239 right_rl
= cast_rl(type
, right_orig
);
241 if ((!left_rl
|| !right_rl
) &&
242 (implied
== RL_EXACT
|| implied
== RL_HARD
|| implied
== RL_FUZZY
))
246 left_rl
= alloc_whole_rl(type
);
248 right_rl
= alloc_whole_rl(type
);
250 /* negative values complicate everything fix this later */
251 if (sval_is_negative(rl_min(right_rl
)))
253 max
= rl_max(left_rl
);
254 min
= sval_type_min(type
);
256 switch (comparison
) {
258 case SPECIAL_UNSIGNED_GT
:
259 min
= sval_type_val(type
, 1);
260 max
= rl_max(left_rl
);
263 case SPECIAL_UNSIGNED_GTE
:
264 min
= sval_type_val(type
, 0);
265 max
= rl_max(left_rl
);
268 min
= sval_type_val(type
, 0);
269 max
= sval_type_val(type
, 0);
272 case SPECIAL_UNSIGNED_LT
:
273 max
= sval_type_val(type
, -1);
276 case SPECIAL_UNSIGNED_LTE
:
277 max
= sval_type_val(type
, 0);
280 if (!left_orig
|| !right_orig
)
282 return rl_binop(left_rl
, '-', right_rl
);
285 if (!sval_binop_overflows(rl_min(left_rl
), '-', rl_max(right_rl
))) {
286 tmp
= sval_binop(rl_min(left_rl
), '-', rl_max(right_rl
));
287 if (sval_cmp(tmp
, min
) > 0)
291 if (!sval_is_max(rl_max(left_rl
))) {
292 tmp
= sval_binop(rl_max(left_rl
), '-', rl_min(right_rl
));
293 if (sval_cmp(tmp
, max
) < 0)
297 if (sval_is_min(min
) && sval_is_max(max
))
300 return cast_rl(type
, alloc_rl(min
, max
));
303 static struct range_list
*handle_mod_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
305 struct range_list
*rl
;
306 sval_t left
, right
, sval
;
308 if (implied
== RL_EXACT
) {
309 if (!get_implied_value(expr
->right
, &right
))
311 if (!get_implied_value(expr
->left
, &left
))
313 sval
= sval_binop(left
, '%', right
);
314 return alloc_rl(sval
, sval
);
316 /* if we can't figure out the right side it's probably hopeless */
317 if (!get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
320 right
= sval_cast(get_type(expr
), right
);
323 rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
324 if (rl
&& rl_max(rl
).uvalue
< right
.uvalue
)
325 right
.uvalue
= rl_max(rl
).uvalue
;
327 return alloc_rl(sval_cast(right
.type
, zero
), right
);
330 static sval_t
sval_lowest_set_bit(sval_t sval
)
335 for (i
= 0; i
< 64; i
++) {
336 if (sval
.uvalue
& 1ULL << i
) {
339 sval
.uvalue
&= ~(1ULL << i
);
345 static struct range_list
*handle_bitwise_AND(struct expression
*expr
, int implied
, int *recurse_cnt
)
348 struct range_list
*left_rl
, *right_rl
;
352 if (implied
!= RL_IMPLIED
&& implied
!= RL_ABSOLUTE
&& implied
!= RL_REAL_ABSOLUTE
)
355 type
= get_type(expr
);
357 if (get_implied_value_internal(expr
->left
, &known
, recurse_cnt
)) {
360 min
= sval_lowest_set_bit(known
);
361 left_rl
= alloc_rl(min
, known
);
362 left_rl
= cast_rl(type
, left_rl
);
363 add_range(&left_rl
, sval_type_val(type
, 0), sval_type_val(type
, 0));
365 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
367 left_rl
= cast_rl(type
, left_rl
);
368 left_rl
= alloc_rl(sval_type_val(type
, 0), rl_max(left_rl
));
370 if (implied
== RL_HARD
)
372 left_rl
= alloc_whole_rl(type
);
376 new_recurse
= *recurse_cnt
;
377 if (*recurse_cnt
>= 200)
378 new_recurse
= 100; /* Let's try super hard to get the mask */
379 if (get_implied_value_internal(expr
->right
, &known
, &new_recurse
)) {
380 sval_t min
, left_max
, mod
;
382 *recurse_cnt
= new_recurse
;
384 min
= sval_lowest_set_bit(known
);
385 right_rl
= alloc_rl(min
, known
);
386 right_rl
= cast_rl(type
, right_rl
);
387 add_range(&right_rl
, sval_type_val(type
, 0), sval_type_val(type
, 0));
389 if (min
.value
!= 0) {
390 left_max
= rl_max(left_rl
);
391 mod
= sval_binop(left_max
, '%', min
);
393 left_max
= sval_binop(left_max
, '-', mod
);
395 if (left_max
.value
> 0 && sval_cmp(left_max
, rl_max(left_rl
)) < 0)
396 left_rl
= remove_range(left_rl
, left_max
, rl_max(left_rl
));
400 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
402 right_rl
= cast_rl(type
, right_rl
);
403 right_rl
= alloc_rl(sval_type_val(type
, 0), rl_max(right_rl
));
405 if (implied
== RL_HARD
)
407 right_rl
= alloc_whole_rl(type
);
411 return rl_intersection(left_rl
, right_rl
);
414 static struct range_list
*use_rl_binop(struct expression
*expr
, int implied
, int *recurse_cnt
)
417 struct range_list
*left_rl
, *right_rl
;
419 if (implied
!= RL_IMPLIED
&& implied
!= RL_ABSOLUTE
&& implied
!= RL_REAL_ABSOLUTE
)
422 type
= get_type(expr
);
424 get_absolute_rl_internal(expr
->left
, &left_rl
, recurse_cnt
);
425 get_absolute_rl_internal(expr
->right
, &right_rl
, recurse_cnt
);
426 left_rl
= cast_rl(type
, left_rl
);
427 right_rl
= cast_rl(type
, right_rl
);
428 if (!left_rl
|| !right_rl
)
431 return rl_binop(left_rl
, expr
->op
, right_rl
);
434 static struct range_list
*handle_right_shift(struct expression
*expr
, int implied
, int *recurse_cnt
)
436 struct range_list
*left_rl
;
440 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
443 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
445 max
= rl_max(left_rl
);
446 min
= rl_min(left_rl
);
448 if (implied
== RL_FUZZY
)
450 max
= sval_type_max(get_type(expr
->left
));
451 min
= sval_type_val(get_type(expr
->left
), 0);
454 if (get_implied_value_internal(expr
->right
, &right
, recurse_cnt
)) {
455 min
= sval_binop(min
, SPECIAL_RIGHTSHIFT
, right
);
456 max
= sval_binop(max
, SPECIAL_RIGHTSHIFT
, right
);
457 } else if (!sval_is_negative(min
)) {
459 max
= sval_type_max(max
.type
);
464 return alloc_rl(min
, max
);
467 static struct range_list
*handle_left_shift(struct expression
*expr
, int implied
, int *recurse_cnt
)
469 struct range_list
*left_rl
, *res
;
474 if (implied
== RL_EXACT
|| implied
== RL_HARD
)
476 /* this is hopeless without the right side */
477 if (!get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
479 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
481 max
= rl_max(left_rl
);
482 min
= rl_min(left_rl
);
483 if (min
.value
== 0) {
488 if (implied
== RL_FUZZY
)
490 max
= sval_type_max(get_type(expr
->left
));
491 min
= sval_type_val(get_type(expr
->left
), 1);
495 max
= sval_binop(max
, SPECIAL_LEFTSHIFT
, right
);
496 min
= sval_binop(min
, SPECIAL_LEFTSHIFT
, right
);
497 res
= alloc_rl(min
, max
);
499 res
= rl_union(res
, rl_zero());
503 static struct range_list
*handle_known_binop(struct expression
*expr
)
507 if (!get_value(expr
->left
, &left
))
509 if (!get_value(expr
->right
, &right
))
511 left
= sval_binop(left
, expr
->op
, right
);
512 return alloc_rl(left
, left
);
515 static int has_actual_ranges(struct range_list
*rl
)
517 struct data_range
*tmp
;
519 FOR_EACH_PTR(rl
, tmp
) {
520 if (sval_cmp(tmp
->min
, tmp
->max
) != 0)
522 } END_FOR_EACH_PTR(tmp
);
526 static struct range_list
*handle_implied_binop(struct range_list
*left_rl
, int op
, struct range_list
*right_rl
)
528 struct range_list
*res_rl
;
529 struct data_range
*left_drange
, *right_drange
;
532 if (!left_rl
|| !right_rl
)
534 if (has_actual_ranges(left_rl
))
536 if (has_actual_ranges(right_rl
))
539 if (ptr_list_size((struct ptr_list
*)left_rl
) * ptr_list_size((struct ptr_list
*)right_rl
) > 20)
544 FOR_EACH_PTR(left_rl
, left_drange
) {
545 FOR_EACH_PTR(right_rl
, right_drange
) {
546 if ((op
== '%' || op
== '/') &&
547 right_drange
->min
.value
== 0)
549 res
= sval_binop(left_drange
->min
, op
, right_drange
->min
);
550 add_range(&res_rl
, res
, res
);
551 } END_FOR_EACH_PTR(right_drange
);
552 } END_FOR_EACH_PTR(left_drange
);
557 static struct range_list
*handle_binop_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
559 struct smatch_state
*state
;
561 struct range_list
*left_rl
, *right_rl
, *rl
;
564 rl
= handle_known_binop(expr
);
567 if (implied
== RL_EXACT
)
570 if (custom_handle_variable
) {
571 rl
= custom_handle_variable(expr
);
576 state
= get_extra_state(expr
);
577 if (state
&& !is_whole_rl(estate_rl(state
)))
578 return clone_rl(estate_rl(state
));
580 type
= get_type(expr
);
581 left_rl
= _get_rl(expr
->left
, implied
, recurse_cnt
);
582 left_rl
= cast_rl(type
, left_rl
);
583 right_rl
= _get_rl(expr
->right
, implied
, recurse_cnt
);
584 right_rl
= cast_rl(type
, right_rl
);
586 if (!left_rl
&& !right_rl
)
589 rl
= handle_implied_binop(left_rl
, expr
->op
, right_rl
);
595 return handle_mod_rl(expr
, implied
, recurse_cnt
);
597 return handle_bitwise_AND(expr
, implied
, recurse_cnt
);
600 return use_rl_binop(expr
, implied
, recurse_cnt
);
601 case SPECIAL_RIGHTSHIFT
:
602 return handle_right_shift(expr
, implied
, recurse_cnt
);
603 case SPECIAL_LEFTSHIFT
:
604 return handle_left_shift(expr
, implied
, recurse_cnt
);
606 return handle_subtract_rl(expr
, implied
, recurse_cnt
);
608 return handle_divide_rl(expr
, implied
, recurse_cnt
);
611 if (!left_rl
|| !right_rl
)
614 if (sval_binop_overflows(rl_min(left_rl
), expr
->op
, rl_min(right_rl
)))
616 if (sval_binop_overflows(rl_max(left_rl
), expr
->op
, rl_max(right_rl
)))
619 min
= sval_binop(rl_min(left_rl
), expr
->op
, rl_min(right_rl
));
620 max
= sval_binop(rl_max(left_rl
), expr
->op
, rl_max(right_rl
));
622 return alloc_rl(min
, max
);
625 static int do_comparison(struct expression
*expr
)
627 struct range_list
*left_ranges
= NULL
;
628 struct range_list
*right_ranges
= NULL
;
629 int poss_true
, poss_false
;
632 type
= get_type(expr
);
633 get_absolute_rl(expr
->left
, &left_ranges
);
634 get_absolute_rl(expr
->right
, &right_ranges
);
636 left_ranges
= cast_rl(type
, left_ranges
);
637 right_ranges
= cast_rl(type
, right_ranges
);
639 poss_true
= possibly_true_rl(left_ranges
, expr
->op
, right_ranges
);
640 poss_false
= possibly_false_rl(left_ranges
, expr
->op
, right_ranges
);
642 free_rl(&left_ranges
);
643 free_rl(&right_ranges
);
645 if (!poss_true
&& !poss_false
)
647 if (poss_true
&& !poss_false
)
649 if (!poss_true
&& poss_false
)
654 static struct range_list
*handle_comparison_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
659 if (expr
->op
== SPECIAL_EQUAL
&& expr
->left
->type
== EXPR_TYPE
) {
660 struct symbol
*left
, *right
;
662 left
= get_real_base_type(expr
->left
->symbol
);
663 right
= get_real_base_type(expr
->left
->symbol
);
669 if (get_value(expr
->left
, &left
) && get_value(expr
->right
, &right
)) {
670 struct data_range tmp_left
, tmp_right
;
674 tmp_right
.min
= right
;
675 tmp_right
.max
= right
;
676 if (true_comparison_range(&tmp_left
, expr
->op
, &tmp_right
))
681 if (implied
== RL_EXACT
)
684 res
= do_comparison(expr
);
690 return alloc_rl(zero
, one
);
693 static struct range_list
*handle_logical_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
699 if (implied
== RL_EXACT
) {
700 if (get_value(expr
->left
, &left
))
702 if (get_value(expr
->right
, &right
))
705 if (get_implied_value_internal(expr
->left
, &left
, recurse_cnt
))
707 if (get_implied_value_internal(expr
->right
, &right
, recurse_cnt
))
712 case SPECIAL_LOGICAL_OR
:
713 if (left_known
&& left
.value
)
715 if (right_known
&& right
.value
)
717 if (left_known
&& right_known
)
720 case SPECIAL_LOGICAL_AND
:
721 if (left_known
&& right_known
) {
722 if (left
.value
&& right
.value
)
731 if (implied
== RL_EXACT
)
734 return alloc_rl(zero
, one
);
737 static struct range_list
*handle_conditional_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
739 struct range_list
*true_rl
, *false_rl
;
741 int final_pass_orig
= final_pass
;
743 if (known_condition_true(expr
->conditional
))
744 return _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
745 if (known_condition_false(expr
->conditional
))
746 return _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
748 if (implied
== RL_EXACT
)
751 if (implied_condition_true(expr
->conditional
))
752 return _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
753 if (implied_condition_false(expr
->conditional
))
754 return _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
757 /* this becomes a problem with deeply nested conditional statements */
761 type
= get_type(expr
);
763 __push_fake_cur_stree();
765 __split_whole_condition(expr
->conditional
);
766 true_rl
= _get_rl(expr
->cond_true
, implied
, recurse_cnt
);
767 __push_true_states();
768 __use_false_states();
769 false_rl
= _get_rl(expr
->cond_false
, implied
, recurse_cnt
);
770 __merge_true_states();
771 __free_fake_cur_stree();
772 final_pass
= final_pass_orig
;
774 if (!true_rl
|| !false_rl
)
776 true_rl
= cast_rl(type
, true_rl
);
777 false_rl
= cast_rl(type
, false_rl
);
779 return rl_union(true_rl
, false_rl
);
782 static int get_fuzzy_max_helper(struct expression
*expr
, sval_t
*max
)
784 struct smatch_state
*state
;
787 if (get_hard_max(expr
, &sval
)) {
792 state
= get_extra_state(expr
);
793 if (!state
|| !estate_has_fuzzy_max(state
))
795 *max
= sval_cast(get_type(expr
), estate_get_fuzzy_max(state
));
799 static int get_fuzzy_min_helper(struct expression
*expr
, sval_t
*min
)
801 struct smatch_state
*state
;
804 state
= get_extra_state(expr
);
805 if (!state
|| !estate_rl(state
))
808 sval
= estate_min(state
);
809 if (sval_is_negative(sval
) && sval_is_min(sval
))
812 if (sval_is_max(sval
))
815 *min
= sval_cast(get_type(expr
), sval
);
819 int get_const_value(struct expression
*expr
, sval_t
*sval
)
824 if (expr
->type
!= EXPR_SYMBOL
|| !expr
->symbol
)
827 if (!(sym
->ctype
.modifiers
& MOD_CONST
))
829 if (get_value(sym
->initializer
, &right
)) {
830 *sval
= sval_cast(get_type(expr
), right
);
836 struct range_list
*var_to_absolute_rl(struct expression
*expr
)
838 struct smatch_state
*state
;
839 struct range_list
*rl
;
841 state
= get_extra_state(expr
);
842 if (!state
|| is_whole_rl(estate_rl(state
))) {
843 state
= get_real_absolute_state(expr
);
844 if (state
&& state
->data
&& !estate_is_whole(state
))
845 return clone_rl(estate_rl(state
));
846 if (get_local_rl(expr
, &rl
) && !is_whole_rl(rl
))
848 if (get_db_type_rl(expr
, &rl
) && !is_whole_rl(rl
))
850 return alloc_whole_rl(get_type(expr
));
852 /* err on the side of saying things are possible */
853 if (!estate_rl(state
))
854 return alloc_whole_rl(get_type(expr
));
855 return clone_rl(estate_rl(state
));
858 static struct range_list
*handle_variable(struct expression
*expr
, int implied
, int *recurse_cnt
)
860 struct smatch_state
*state
;
861 struct range_list
*rl
;
862 sval_t sval
, min
, max
;
865 if (get_const_value(expr
, &sval
))
866 return alloc_rl(sval
, sval
);
868 if (custom_handle_variable
) {
869 rl
= custom_handle_variable(expr
);
871 return var_to_absolute_rl(expr
);
875 if (implied
== RL_EXACT
)
878 type
= get_type(expr
);
879 if (type
&& type
->type
== SYM_FN
)
880 return alloc_rl(fn_ptr_min
, fn_ptr_max
);
886 state
= get_extra_state(expr
);
887 if (!state
|| !state
->data
) {
888 if (implied
== RL_HARD
)
890 if (get_local_rl(expr
, &rl
))
892 if (get_db_type_rl(expr
, &rl
))
896 if (implied
== RL_HARD
&& !estate_has_hard_max(state
))
898 return clone_rl(estate_rl(state
));
899 case RL_REAL_ABSOLUTE
: {
900 struct smatch_state
*abs_state
;
902 state
= get_extra_state(expr
);
903 abs_state
= get_real_absolute_state(expr
);
905 if (estate_rl(state
) && estate_rl(abs_state
)) {
906 return clone_rl(rl_intersection(estate_rl(state
),
907 estate_rl(abs_state
)));
908 } else if (estate_rl(state
)) {
909 return clone_rl(estate_rl(state
));
910 } else if (estate_is_empty(state
)) {
912 * FIXME: we don't handle empty extra states correctly.
914 * The real abs rl is supposed to be filtered by the
915 * extra state if there is one. We don't bother keeping
916 * the abs state in sync all the time because we know it
917 * will be filtered later.
919 * It's not totally obvious to me how they should be
920 * handled. Perhaps we should take the whole rl and
921 * filter by the imaginary states. Perhaps we should
922 * just go with the empty state.
924 * Anyway what we currently do is return NULL here and
925 * that gets translated into the whole range in
926 * get_real_absolute_rl().
930 } else if (estate_rl(abs_state
)) {
931 return clone_rl(estate_rl(abs_state
));
934 if (get_local_rl(expr
, &rl
))
936 if (get_db_type_rl(expr
, &rl
))
941 if (!get_fuzzy_min_helper(expr
, &min
))
942 min
= sval_type_min(get_type(expr
));
943 if (!get_fuzzy_max_helper(expr
, &max
))
945 /* fuzzy ranges are often inverted */
946 if (sval_cmp(min
, max
) > 0) {
951 return alloc_rl(min
, max
);
956 static sval_t
handle_sizeof(struct expression
*expr
)
961 ret
= sval_blank(expr
);
962 sym
= expr
->cast_type
;
964 sym
= evaluate_expression(expr
->cast_expression
);
966 __silence_warnings_for_stmt
= true;
971 * Expressions of restricted types will possibly get
972 * promoted - check that here. I'm not sure how this works,
973 * the problem is that sizeof(le16) shouldn't be promoted and
974 * the original code did that... Let's if zero this out and
978 if (is_restricted_type(sym
)) {
979 if (type_bits(sym
) < bits_in_int
)
983 if (is_fouled_type(sym
))
986 examine_symbol_type(sym
);
988 ret
.type
= size_t_ctype
;
989 if (type_bits(sym
) <= 0) /* sizeof(void) */ {
990 if (get_real_base_type(sym
) == &void_ctype
)
995 ret
.value
= type_bytes(sym
);
1000 static struct range_list
*handle_strlen(struct expression
*expr
, int implied
, int *recurse_cnt
)
1002 struct range_list
*rl
;
1003 struct expression
*arg
;
1004 sval_t sval
= { .type
= &ulong_ctype
};
1006 if (implied
== RL_EXACT
)
1009 arg
= get_argument_from_call_expr(expr
->args
, 0);
1012 if (arg
->type
== EXPR_STRING
) {
1013 sval
.value
= arg
->string
->length
- 1;
1014 return alloc_rl(sval
, sval
);
1017 if (implied
== RL_HARD
|| implied
== RL_FUZZY
)
1020 if (get_implied_return(expr
, &rl
))
1026 static struct range_list
*handle_call_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
1028 struct range_list
*rl
;
1030 if (sym_name_is("__builtin_expect", expr
->fn
) ||
1031 sym_name_is("__builtin_bswap16", expr
->fn
) ||
1032 sym_name_is("__builtin_bswap32", expr
->fn
) ||
1033 sym_name_is("__builtin_bswap64", expr
->fn
)) {
1034 struct expression
*arg
;
1036 arg
= get_argument_from_call_expr(expr
->args
, 0);
1037 return _get_rl(arg
, implied
, recurse_cnt
);
1040 if (sym_name_is("strlen", expr
->fn
))
1041 return handle_strlen(expr
, implied
, recurse_cnt
);
1043 if (implied
== RL_EXACT
|| implied
== RL_HARD
|| implied
== RL_FUZZY
)
1046 if (custom_handle_variable
) {
1047 rl
= custom_handle_variable(expr
);
1052 if (get_implied_return(expr
, &rl
))
1054 return db_return_vals(expr
);
1057 static struct range_list
*handle_cast(struct expression
*expr
, int implied
, int *recurse_cnt
)
1059 struct range_list
*rl
;
1060 struct symbol
*type
;
1062 type
= get_type(expr
);
1063 rl
= _get_rl(expr
->cast_expression
, implied
, recurse_cnt
);
1065 return cast_rl(type
, rl
);
1066 if (implied
== RL_ABSOLUTE
|| implied
== RL_REAL_ABSOLUTE
)
1067 return alloc_whole_rl(type
);
1068 if (implied
== RL_IMPLIED
&& type
&&
1069 type_bits(type
) > 0 && type_bits(type
) < 32)
1070 return alloc_whole_rl(type
);
1074 static struct range_list
*_get_rl(struct expression
*expr
, int implied
, int *recurse_cnt
)
1076 struct range_list
*rl
;
1077 struct symbol
*type
;
1080 type
= get_type(expr
);
1081 expr
= strip_parens(expr
);
1085 if (++(*recurse_cnt
) >= 200)
1088 switch(expr
->type
) {
1090 case EXPR_FORCE_CAST
:
1091 case EXPR_IMPLIED_CAST
:
1092 rl
= handle_cast(expr
, implied
, recurse_cnt
);
1096 expr
= strip_expr(expr
);
1100 switch (expr
->type
) {
1102 sval
= sval_from_val(expr
, expr
->value
);
1103 rl
= alloc_rl(sval
, sval
);
1106 rl
= handle_preop_rl(expr
, implied
, recurse_cnt
);
1109 rl
= _get_rl(expr
->unop
, implied
, recurse_cnt
);
1112 rl
= handle_binop_rl(expr
, implied
, recurse_cnt
);
1115 rl
= handle_comparison_rl(expr
, implied
, recurse_cnt
);
1118 rl
= handle_logical_rl(expr
, implied
, recurse_cnt
);
1120 case EXPR_PTRSIZEOF
:
1122 sval
= handle_sizeof(expr
);
1123 rl
= alloc_rl(sval
, sval
);
1126 case EXPR_CONDITIONAL
:
1127 rl
= handle_conditional_rl(expr
, implied
, recurse_cnt
);
1130 rl
= handle_call_rl(expr
, implied
, recurse_cnt
);
1133 rl
= handle_variable(expr
, implied
, recurse_cnt
);
1139 if (type
&& (implied
== RL_ABSOLUTE
|| implied
== RL_REAL_ABSOLUTE
))
1140 return alloc_whole_rl(type
);
1144 /* returns 1 if it can get a value literal or else returns 0 */
1145 int get_value(struct expression
*expr
, sval_t
*sval
)
1147 struct range_list
*rl
;
1148 int recurse_cnt
= 0;
1150 rl
= _get_rl(expr
, RL_EXACT
, &recurse_cnt
);
1151 if (!rl_to_sval(rl
, sval
))
1156 static int get_implied_value_internal(struct expression
*expr
, sval_t
*sval
, int *recurse_cnt
)
1158 struct range_list
*rl
;
1160 rl
= _get_rl(expr
, RL_IMPLIED
, recurse_cnt
);
1161 if (!rl_to_sval(rl
, sval
))
1166 int get_implied_value(struct expression
*expr
, sval_t
*sval
)
1168 struct range_list
*rl
;
1169 int recurse_cnt
= 0;
1171 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1172 if (!rl_to_sval(rl
, sval
))
1177 int get_implied_min(struct expression
*expr
, sval_t
*sval
)
1179 struct range_list
*rl
;
1180 int recurse_cnt
= 0;
1182 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1189 int get_implied_max(struct expression
*expr
, sval_t
*sval
)
1191 struct range_list
*rl
;
1192 int recurse_cnt
= 0;
1194 rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1201 int get_implied_rl(struct expression
*expr
, struct range_list
**rl
)
1203 int recurse_cnt
= 0;
1205 *rl
= _get_rl(expr
, RL_IMPLIED
, &recurse_cnt
);
1211 static int get_absolute_rl_internal(struct expression
*expr
, struct range_list
**rl
, int *recurse_cnt
)
1213 *rl
= _get_rl(expr
, RL_ABSOLUTE
, recurse_cnt
);
1215 *rl
= alloc_whole_rl(get_type(expr
));
1219 int get_absolute_rl(struct expression
*expr
, struct range_list
**rl
)
1221 int recurse_cnt
= 0;
1223 *rl
= _get_rl(expr
, RL_ABSOLUTE
, &recurse_cnt
);
1225 *rl
= alloc_whole_rl(get_type(expr
));
1229 int get_real_absolute_rl(struct expression
*expr
, struct range_list
**rl
)
1231 int recurse_cnt
= 0;
1233 *rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1235 *rl
= alloc_whole_rl(get_type(expr
));
1239 int custom_get_absolute_rl(struct expression
*expr
,
1240 struct range_list
*(*fn
)(struct expression
*expr
),
1241 struct range_list
**rl
)
1243 int recurse_cnt
= 0;
1246 custom_handle_variable
= fn
;
1247 *rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1248 custom_handle_variable
= NULL
;
1252 int get_implied_rl_var_sym(const char *var
, struct symbol
*sym
, struct range_list
**rl
)
1254 struct smatch_state
*state
;
1256 state
= get_state(SMATCH_EXTRA
, var
, sym
);
1257 *rl
= estate_rl(state
);
1263 int get_hard_max(struct expression
*expr
, sval_t
*sval
)
1265 struct range_list
*rl
;
1266 int recurse_cnt
= 0;
1268 rl
= _get_rl(expr
, RL_HARD
, &recurse_cnt
);
1275 int get_fuzzy_min(struct expression
*expr
, sval_t
*sval
)
1277 struct range_list
*rl
;
1279 int recurse_cnt
= 0;
1281 rl
= _get_rl(expr
, RL_FUZZY
, &recurse_cnt
);
1285 if (sval_is_negative(tmp
) && sval_is_min(tmp
))
1291 int get_fuzzy_max(struct expression
*expr
, sval_t
*sval
)
1293 struct range_list
*rl
;
1295 int recurse_cnt
= 0;
1297 rl
= _get_rl(expr
, RL_FUZZY
, &recurse_cnt
);
1301 if (max
.uvalue
> INT_MAX
- 10000)
1307 int get_absolute_min(struct expression
*expr
, sval_t
*sval
)
1309 struct range_list
*rl
;
1310 struct symbol
*type
;
1311 int recurse_cnt
= 0;
1313 type
= get_type(expr
);
1315 type
= &llong_ctype
; // FIXME: this is wrong but places assume get type can't fail.
1316 rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1320 *sval
= sval_type_min(type
);
1322 if (sval_cmp(*sval
, sval_type_min(type
)) < 0)
1323 *sval
= sval_type_min(type
);
1327 int get_absolute_max(struct expression
*expr
, sval_t
*sval
)
1329 struct range_list
*rl
;
1330 struct symbol
*type
;
1331 int recurse_cnt
= 0;
1333 type
= get_type(expr
);
1335 type
= &llong_ctype
;
1336 rl
= _get_rl(expr
, RL_REAL_ABSOLUTE
, &recurse_cnt
);
1340 *sval
= sval_type_max(type
);
1342 if (sval_cmp(sval_type_max(type
), *sval
) < 0)
1343 *sval
= sval_type_max(type
);
1347 int known_condition_true(struct expression
*expr
)
1354 if (get_value(expr
, &tmp
) && tmp
.value
)
1360 int known_condition_false(struct expression
*expr
)
1368 if (expr
->type
== EXPR_CALL
) {
1369 if (sym_name_is("__builtin_constant_p", expr
->fn
))
1375 int implied_condition_true(struct expression
*expr
)
1382 if (known_condition_true(expr
))
1384 if (get_implied_value(expr
, &tmp
) && tmp
.value
)
1387 if (expr
->type
== EXPR_POSTOP
)
1388 return implied_condition_true(expr
->unop
);
1390 if (expr
->type
== EXPR_PREOP
&& expr
->op
== SPECIAL_DECREMENT
)
1391 return implied_not_equal(expr
->unop
, 1);
1392 if (expr
->type
== EXPR_PREOP
&& expr
->op
== SPECIAL_INCREMENT
)
1393 return implied_not_equal(expr
->unop
, -1);
1395 expr
= strip_expr(expr
);
1396 switch (expr
->type
) {
1398 if (do_comparison(expr
) == 1)
1402 if (expr
->op
== '!') {
1403 if (implied_condition_false(expr
->unop
))
1409 if (implied_not_equal(expr
, 0) == 1)
1416 int implied_condition_false(struct expression
*expr
)
1418 struct expression
*tmp
;
1424 if (known_condition_false(expr
))
1427 switch (expr
->type
) {
1429 if (do_comparison(expr
) == 2)
1432 if (expr
->op
== '!') {
1433 if (implied_condition_true(expr
->unop
))
1437 tmp
= strip_expr(expr
);
1439 return implied_condition_false(tmp
);
1442 if (get_implied_value(expr
, &sval
) && sval
.value
== 0)
1449 int can_integer_overflow(struct symbol
*type
, struct expression
*expr
)
1452 sval_t lmax
, rmax
, res
;
1457 expr
= strip_expr(expr
);
1459 if (expr
->type
== EXPR_ASSIGNMENT
) {
1461 case SPECIAL_MUL_ASSIGN
:
1464 case SPECIAL_ADD_ASSIGN
:
1467 case SPECIAL_SHL_ASSIGN
:
1468 op
= SPECIAL_LEFTSHIFT
;
1473 } else if (expr
->type
== EXPR_BINOP
) {
1474 if (expr
->op
!= '*' && expr
->op
!= '+' && expr
->op
!= SPECIAL_LEFTSHIFT
)
1481 get_absolute_max(expr
->left
, &lmax
);
1482 get_absolute_max(expr
->right
, &rmax
);
1484 if (sval_binop_overflows(lmax
, op
, rmax
))
1487 res
= sval_binop(lmax
, op
, rmax
);
1488 if (sval_cmp(res
, sval_type_max(type
)) > 0)