2 * sparse/smatch_constraints.c
4 * Copyright (C) 2010 Dan Carpenter.
6 * Licensed under the Open Software License version 1.1
11 * smatch_constraints.c is for tracking how variables are related
17 * This is stored in a field in the smatch_extra dinfo.
19 * Normally the way that variables become related is through a
20 * condition and you say: add_constraint_expr(left, '<', right);
21 * The other way it can happen is if you have an assignment:
22 * set_equiv(left, right);
24 * One two variables "a" and "b" are related if then if we find
25 * that "a" is greater than 0 we need to update "b".
27 * When a variable gets modified all the old relationships are
28 * deleted. remove_contraints(expr);
30 * Also we need an is_true_constraint(left, '<', right) and
31 * is_false_constraint (left, '<', right). This is used by
37 #include "smatch_slist.h"
38 #include "smatch_extra.h"
40 ALLOCATOR(relation
, "related variables");
43 * set_equiv() is only used for assignments where we set one variable
44 * equal to the other. a = b;. It's not used for if conditions where
47 void set_equiv(struct expression
*left
, struct expression
*right
)
49 struct sm_state
*right_sm
;
50 struct smatch_state
*state
;
53 struct symbol
*left_sym
;
55 left_name
= get_variable_from_expr(left
, &left_sym
);
56 if (!left_name
|| !left_sym
)
59 right_sm
= get_sm_state_expr(SMATCH_EXTRA
, right
);
61 right_sm
= set_state_expr(SMATCH_EXTRA
, right
, extra_undefined());
65 remove_from_equiv(left_name
, left_sym
);
67 state
= clone_estate(right_sm
->state
);
68 if (!estate_related(state
))
69 add_equiv(state
, right_sm
->name
, right_sm
->sym
);
70 add_equiv(state
, left_name
, left_sym
);
72 FOR_EACH_PTR(estate_related(state
), rel
) {
73 struct sm_state
*new_sm
;
75 new_sm
= clone_sm(right_sm
);
76 new_sm
->name
= rel
->name
;
77 new_sm
->sym
= rel
->sym
;
78 new_sm
->state
= state
;
80 } END_FOR_EACH_PTR(rel
);
82 free_string(left_name
);
85 static struct relation
*alloc_relation(int op
, const char *name
, struct symbol
*sym
)
89 tmp
= __alloc_relation(0);
91 tmp
->name
= alloc_string(name
);
96 struct related_list
*clone_related_list(struct related_list
*related
)
99 struct related_list
*to_list
= NULL
;
101 FOR_EACH_PTR(related
, rel
) {
102 add_ptr_list(&to_list
, rel
);
103 } END_FOR_EACH_PTR(rel
);
108 static int cmp_relation(struct relation
*a
, struct relation
*b
)
125 ret
= strcmp(a
->name
, b
->name
);
133 struct related_list
*get_shared_relations(struct related_list
*one
,
134 struct related_list
*two
)
136 struct related_list
*ret
= NULL
;
137 struct relation
*one_rel
;
138 struct relation
*two_rel
;
140 PREPARE_PTR_LIST(one
, one_rel
);
141 PREPARE_PTR_LIST(two
, two_rel
);
143 if (!one_rel
|| !two_rel
)
145 if (cmp_relation(one_rel
, two_rel
) < 0) {
146 NEXT_PTR_LIST(one_rel
);
147 } else if (cmp_relation(one_rel
, two_rel
) == 0) {
148 add_ptr_list(&ret
, one_rel
);
149 NEXT_PTR_LIST(one_rel
);
150 NEXT_PTR_LIST(two_rel
);
152 NEXT_PTR_LIST(two_rel
);
155 FINISH_PTR_LIST(two_rel
);
156 FINISH_PTR_LIST(one_rel
);
161 static void debug_addition(struct smatch_state
*state
, int op
, const char *name
)
163 struct relation
*tmp
;
165 if (!option_debug_related
)
170 FOR_EACH_PTR(estate_related(state
), tmp
) {
171 sm_printf("%s %s ", show_special(tmp
->op
), tmp
->name
);
172 } END_FOR_EACH_PTR(tmp
);
173 sm_printf(") <-- %s %s\n", show_special(op
), name
);
176 void add_related(struct smatch_state
*state
, int op
, const char *name
, struct symbol
*sym
)
178 struct data_info
*dinfo
;
179 struct relation
*tmp
;
180 struct relation
*new;
182 debug_addition(state
, op
, name
);
184 dinfo
= get_dinfo(state
);
185 FOR_EACH_PTR(dinfo
->related
, tmp
) {
186 if (tmp
->op
< op
|| tmp
->sym
< sym
|| strcmp(tmp
->name
, name
) < 0)
188 if (tmp
->op
== op
&& tmp
->sym
== sym
&& !strcmp(tmp
->name
, name
))
190 new = alloc_relation(op
, name
, sym
);
191 INSERT_CURRENT(new, tmp
);
193 } END_FOR_EACH_PTR(tmp
);
194 new = alloc_relation(op
, name
, sym
);
195 add_ptr_list(&dinfo
->related
, new);
198 void del_related(struct smatch_state
*state
, int op
, const char *name
, struct symbol
*sym
)
200 struct relation
*tmp
;
202 FOR_EACH_PTR(estate_related(state
), tmp
) {
203 if (tmp
->sym
< sym
|| strcmp(tmp
->name
, name
) < 0)
205 if (tmp
->sym
== sym
&& !strcmp(tmp
->name
, name
)) {
206 DELETE_CURRENT_PTR(tmp
);
210 } END_FOR_EACH_PTR(tmp
);
213 void add_equiv(struct smatch_state
*state
, const char *name
, struct symbol
*sym
)
215 add_related(state
, SPECIAL_EQUAL
, name
, sym
);
218 static void del_equiv(struct smatch_state
*state
, const char *name
, struct symbol
*sym
)
220 del_related(state
, SPECIAL_EQUAL
, name
, sym
);
223 void remove_from_equiv(const char *name
, struct symbol
*sym
)
225 struct sm_state
*orig_sm
;
226 struct relation
*rel
;
227 struct smatch_state
*state
;
228 struct related_list
*to_update
;
230 // FIXME equiv => related
231 orig_sm
= get_sm_state(SMATCH_EXTRA
, name
, sym
);
232 if (!orig_sm
|| !get_dinfo(orig_sm
->state
)->related
)
235 state
= clone_estate(orig_sm
->state
);
236 del_equiv(state
, name
, sym
);
237 to_update
= get_dinfo(state
)->related
;
238 if (ptr_list_size((struct ptr_list
*)get_dinfo(state
)->related
) == 1)
239 get_dinfo(state
)->related
= NULL
;
241 FOR_EACH_PTR(to_update
, rel
) {
242 struct sm_state
*new_sm
;
244 new_sm
= clone_sm(orig_sm
);
245 new_sm
->name
= rel
->name
;
246 new_sm
->sym
= rel
->sym
;
247 new_sm
->state
= state
;
249 } END_FOR_EACH_PTR(rel
);
252 void remove_from_equiv_expr(struct expression
*expr
)
257 name
= get_variable_from_expr(expr
, &sym
);
260 remove_from_equiv(name
, sym
);
265 void add_constrain_expr(struct expression
*left
, int op
, struct expression
*right
)
270 void set_equiv_state_expr(int id
, struct expression
*expr
, struct smatch_state
*state
)
272 struct relation
*rel
;
273 struct smatch_state
*estate
;
275 estate
= get_state_expr(SMATCH_EXTRA
, expr
);
280 FOR_EACH_PTR(get_dinfo(estate
)->related
, rel
) {
281 if (rel
->op
!= SPECIAL_EQUAL
)
283 set_state(id
, rel
->name
, rel
->sym
, state
);
284 } END_FOR_EACH_PTR(rel
);