1 /*
2 * Copyright (C) 2016 Oracle.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 */
17
18 /*
19 * Say you have a condition like:
20 *
21 * if (foo < 0)
22 * return foo;
23 *
24 * But we actually know that foo is zero. Then in smatch_extra.c we set "foo"
25 * to the empty state and then for the return statement we say that "foo" is
26 * s32min-s32max because we can't return the empty state.
27 *
28 * This file is supposed to provide an alternative to say that actually "foo" is
29 * less than zero.
30 *
31 */
32
33 #include "smatch.h"
34 #include "smatch_slist.h"
35 #include "smatch_extra.h"
36
37 static int my_id;
38
empty_state(struct sm_state * sm)39 static struct smatch_state *empty_state(struct sm_state *sm)
40 {
41 return alloc_estate_empty();
42 }
43
merge_is_empty(struct smatch_state * s1,struct smatch_state * s2)44 struct smatch_state *merge_is_empty(struct smatch_state *s1, struct smatch_state *s2)
45 {
46 return alloc_estate_empty();
47 }
48
reset(struct sm_state * sm,struct expression * mod_expr)49 static void reset(struct sm_state *sm, struct expression *mod_expr)
50 {
51 set_state(my_id, sm->name, sm->sym, alloc_estate_empty());
52 }
53
__save_imaginary_state(struct expression * expr,struct range_list * true_rl,struct range_list * false_rl)54 void __save_imaginary_state(struct expression *expr, struct range_list *true_rl, struct range_list *false_rl)
55 {
56 if (__in_pre_condition)
57 return;
58 set_true_false_states_expr(my_id, expr, alloc_estate_rl(true_rl), alloc_estate_rl(false_rl));
59 }
60
get_imaginary_absolute(struct expression * expr,struct range_list ** rl)61 int get_imaginary_absolute(struct expression *expr, struct range_list **rl)
62 {
63 struct smatch_state *state;
64
65 *rl = NULL;
66
67 state = get_state_expr(my_id, expr);
68 if (!state || !estate_rl(state))
69 return 0;
70
71 *rl = estate_rl(state);
72 return 1;
73 }
74
register_imaginary_absolute(int id)75 void register_imaginary_absolute(int id)
76 {
77 my_id = id;
78
79 set_dynamic_states(my_id);
80 add_unmatched_state_hook(my_id, &empty_state);
81 add_merge_hook(my_id, &merge_is_empty);
82 add_modification_hook(my_id, &reset);
83 }
84
85