2 * Copyright (C) 2015 Oracle.
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
19 #include "smatch_slist.h"
20 #include "smatch_extra.h"
22 static bool is_non_null_array(struct expression
*expr
)
29 type
= get_type(expr
);
30 if (!type
|| type
->type
!= SYM_ARRAY
)
32 if (expr
->type
== EXPR_SYMBOL
)
34 if (implied_not_equal(expr
, 0))
37 /* verify that it's not the first member of the struct */
38 if (expr
->type
!= EXPR_DEREF
|| !expr
->member
)
40 sym
= expr_to_sym(expr
);
43 type
= get_real_base_type(sym
);
44 if (!type
|| type
->type
!= SYM_PTR
)
46 type
= get_real_base_type(type
);
47 if (type
->type
!= SYM_STRUCT
)
51 FOR_EACH_PTR(type
->symbol_list
, tmp
) {
55 if (strcmp(expr
->member
->name
, tmp
->ident
->name
) == 0) {
60 } END_FOR_EACH_PTR(tmp
);
65 int get_member_offset(struct symbol
*type
, const char *member_name
)
70 if (!type
|| type
->type
!= SYM_STRUCT
)
74 FOR_EACH_PTR(type
->symbol_list
, tmp
) {
75 offset
= ALIGN(offset
, tmp
->ctype
.alignment
);
77 strcmp(member_name
, tmp
->ident
->name
) == 0) {
80 offset
+= type_bytes(tmp
);
81 } END_FOR_EACH_PTR(tmp
);
85 int get_member_offset_from_deref(struct expression
*expr
)
91 if (expr
->type
!= EXPR_DEREF
) /* hopefully, this doesn't happen */
94 if (expr
->member_offset
>= 0)
95 return expr
->member_offset
;
97 member
= expr
->member
;
101 type
= get_type(expr
->deref
);
102 if (!type
|| type
->type
!= SYM_STRUCT
)
105 offset
= get_member_offset(type
, member
->name
);
107 expr
->member_offset
= offset
;
111 static void add_offset_to_pointer(struct range_list
**rl
, int offset
)
113 sval_t min
, max
, remove
, sval
;
114 struct range_list
*orig
= *rl
;
117 * Ha ha. Treating zero as a special case means I'm correct at least a
118 * tiny fraction of the time. Which is better than nothing.
124 if (is_unknown_ptr(orig
))
128 * This function doesn't necessarily work how you might expect...
130 * Say you have s64min-(-1),1-s64max and you add 8 then I guess what
131 * we want to say is maybe something like 9-s64max. This shows that the
132 * min it could be is 9 which is potentially useful information. But
133 * if we start with (-12),5000000-57777777 and we add 8 then we'd want
134 * the result to be (-4),5000008-57777777 but (-4),5000000-57777777 is
135 * also probably acceptable. If you start with s64min-s64max then the
136 * result should be 8-s64max.
140 /* We do the math on void pointer type, because this isn't "&v + 16" it
141 * is &v->sixteenth_byte.
143 orig
= cast_rl(&ptr_ctype
, orig
);
144 min
= sval_type_min(&ptr_ctype
);
146 max
= sval_type_max(&ptr_ctype
);
148 if (!orig
|| is_whole_rl(orig
)) {
149 *rl
= alloc_rl(min
, max
);
154 max
.uvalue
= rl_max(orig
).uvalue
;
155 if (max
.uvalue
> sval_type_max(&ptr_ctype
).uvalue
- offset
) {
156 remove
= sval_type_max(&ptr_ctype
);
157 remove
.uvalue
-= offset
;
158 orig
= remove_range(orig
, remove
, max
);
161 sval
.type
= &int_ctype
;
164 *rl
= rl_binop(orig
, '+', alloc_rl(sval
, sval
));
167 static struct range_list
*where_allocated_rl(struct symbol
*sym
)
172 return alloc_rl(valid_ptr_min_sval
, valid_ptr_max_sval
);
175 int get_address_rl(struct expression
*expr
, struct range_list
**rl
)
177 expr
= strip_expr(expr
);
181 if (expr
->type
== EXPR_STRING
) {
182 *rl
= alloc_rl(valid_ptr_min_sval
, valid_ptr_max_sval
);
186 if (expr
->type
== EXPR_PREOP
&& expr
->op
== '&') {
187 struct expression
*unop
;
189 unop
= strip_expr(expr
->unop
);
190 if (unop
->type
== EXPR_SYMBOL
) {
191 *rl
= where_allocated_rl(unop
->symbol
);
195 if (unop
->type
== EXPR_DEREF
&& unop
->member
) {
196 struct range_list
*unop_rl
;
197 int offset
= get_member_offset_from_deref(unop
);
202 unop
= strip_expr(unop
->unop
);
203 if (get_implied_rl(unop
, &unop_rl
)) {
205 add_offset_to_pointer(rl
, offset
);
210 * If the offset is non-zero that means either valid
211 * pointer or we are already toasted beyond our ability
216 *rl
= alloc_rl(valid_ptr_min_sval
, valid_ptr_max_sval
);
226 if (is_non_null_array(expr
)) {
227 *rl
= alloc_rl(array_min_sval
, array_max_sval
);