2 * sparse/smatch_states.c
4 * Copyright (C) 2006 Dan Carpenter.
6 * Licensed under the Open Software License version 1.1
11 * You have a lists of states. kernel = locked, foo = NULL, ...
12 * When you hit an if {} else {} statement then you swap the list
13 * of states for a different list of states. The lists are stored
16 * At the beginning of this file there are list of the stacks that
17 * we use. Each function in this file does something to one of
20 * So the smatch_flow.c understands code but it doesn't understand states.
21 * smatch_flow calls functions in this file. This file calls functions
22 * in smatch_slist.c which just has boring generic plumbing for handling
23 * state lists. But really it's this file where all the magic happens.
30 #include "smatch_slist.h"
32 struct smatch_state undefined
= { .name
= "undefined" };
33 struct smatch_state merged
= { .name
= "merged" };
34 struct smatch_state true_state
= { .name
= "true" };
35 struct smatch_state false_state
= { .name
= "false" };
37 static struct state_list
*cur_slist
; /* current states */
39 static struct state_list_stack
*true_stack
; /* states after a t/f branch */
40 static struct state_list_stack
*false_stack
;
41 static struct state_list_stack
*pre_cond_stack
; /* states before a t/f branch */
43 static struct state_list_stack
*cond_true_stack
; /* states affected by a branch */
44 static struct state_list_stack
*cond_false_stack
;
46 static struct state_list_stack
*break_stack
;
47 static struct state_list_stack
*switch_stack
;
48 static struct state_list_stack
*default_stack
;
49 static struct state_list_stack
*continue_stack
;
50 static struct state_list_stack
*false_only_stack
;
52 static struct named_stack
*goto_stack
;
54 struct state_list_stack
*implied_pools
;
58 void __print_cur_slist()
60 __print_slist(cur_slist
);
63 static int unreachable()
65 static int reset_warnings
= 1;
72 if (reset_warnings
|| debug_states
)
73 smatch_msg("ignoring unreachable code.");
78 void set_state(const char *name
, int owner
, struct symbol
*sym
,
79 struct smatch_state
*state
)
85 struct smatch_state
*s
;
87 s
= get_state(name
, owner
, sym
);
89 printf("%d new state. name='%s' owner=%d: %s\n",
90 get_lineno(), name
, owner
, show_state(state
));
92 printf("%d state change name='%s' owner=%d: %s => %s\n",
93 get_lineno(), name
, owner
, show_state(s
),
97 if (owner
!= -1 && unreachable())
100 set_state_slist(&cur_slist
, name
, owner
, sym
, state
);
102 if (cond_true_stack
) {
103 set_state_stack(&cond_true_stack
, name
, owner
, sym
, state
);
104 set_state_stack(&cond_false_stack
, name
, owner
, sym
, state
);
108 struct smatch_state
*get_state(const char *name
, int owner
, struct symbol
*sym
)
110 return get_state_slist(cur_slist
, name
, owner
, sym
);
113 struct state_list
*get_possible_states(const char *name
, int owner
,
116 struct sm_state
*sms
;
118 sms
= get_sm_state_slist(cur_slist
, name
, owner
, sym
);
120 return sms
->possible
;
124 struct sm_state
*get_sm_state(const char *name
, int owner
, struct symbol
*sym
)
126 return get_sm_state_slist(cur_slist
, name
, owner
, sym
);
129 void delete_state(const char *name
, int owner
, struct symbol
*sym
)
131 delete_state_slist(&cur_slist
, name
, owner
, sym
);
134 struct state_list
*get_all_states(int owner
)
136 struct state_list
*slist
= NULL
;
137 struct sm_state
*tmp
;
139 FOR_EACH_PTR(cur_slist
, tmp
) {
140 if (tmp
->owner
== owner
) {
141 add_ptr_list(&slist
, tmp
);
143 } END_FOR_EACH_PTR(tmp
);
148 struct state_list
*__get_cur_slist()
153 void set_true_false_states(const char *name
, int owner
, struct symbol
*sym
,
154 struct smatch_state
*true_state
,
155 struct smatch_state
*false_state
)
157 /* fixme. save history */
160 struct smatch_state
*tmp
;
162 tmp
= get_state(name
, owner
, sym
);
163 SM_DEBUG("%d set_true_false '%s'. Was %s. Now T:%s F:%s\n",
164 get_lineno(), name
, show_state(tmp
),
165 show_state(true_state
), show_state(false_state
));
171 if (!cond_false_stack
|| !cond_true_stack
) {
172 printf("Error: missing true/false stacks\n");
177 set_state_slist(&cur_slist
, name
, owner
, sym
, true_state
);
178 set_state_stack(&cond_true_stack
, name
, owner
, sym
, true_state
);
181 set_state_stack(&cond_false_stack
, name
, owner
, sym
, false_state
);
186 del_slist(&cur_slist
);
190 * At the start of every function we mark the path
191 * as unnull. That there is always at least one state
192 * in the cur_slist until nullify_path is called. This
193 * is used in merge_slist() for the first null check.
196 void __unnullify_path()
198 set_state("unnull_path", -1, NULL
, &true_state
);
208 void clear_all_states()
210 struct named_slist
*named_slist
;
213 del_slist_stack(&true_stack
);
214 del_slist_stack(&false_stack
);
215 del_slist_stack(&false_only_stack
);
216 del_slist_stack(&pre_cond_stack
);
217 del_slist_stack(&cond_true_stack
);
218 del_slist_stack(&cond_false_stack
);
219 del_slist_stack(&break_stack
);
220 del_slist_stack(&switch_stack
);
221 del_slist_stack(&continue_stack
);
222 del_slist_stack(&implied_pools
);
224 FOR_EACH_PTR(goto_stack
, named_slist
) {
225 del_slist(&named_slist
->slist
);
226 } END_FOR_EACH_PTR(named_slist
);
227 __free_ptr_list((struct ptr_list
**)&goto_stack
);
231 void __push_cond_stacks()
233 push_slist(&cond_true_stack
, NULL
);
234 push_slist(&cond_false_stack
, NULL
);
238 * This combines the pre cond states with either the true or false states.
240 * a = kmalloc() ; if (a !! foo(a)
241 * In the pre state a is possibly null. In the true state it is non null.
242 * In the false state it is null. Combine the pre and the false to get
243 * that when we call 'foo', 'a' is null.
246 static void __use_cond_stack(struct state_list_stack
**stack
)
248 struct state_list
*slist
;
250 del_slist(&cur_slist
);
252 cur_slist
= pop_slist(&pre_cond_stack
);
253 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
255 slist
= pop_slist(stack
);
256 overwrite_slist(slist
, &cur_slist
);
257 push_slist(stack
, slist
);
260 void __save_false_states_for_later()
262 struct state_list
*pre_conditions
;
263 struct state_list
*false_states
;
264 struct state_list
*tmp
;
266 pre_conditions
= pop_slist(&pre_cond_stack
);
267 false_states
= pop_slist(&cond_false_stack
);
268 tmp
= clone_slist(pre_conditions
);
270 overwrite_slist(false_states
, &tmp
);
272 push_slist(&pre_cond_stack
, tmp
);
273 push_slist(&pre_cond_stack
, pre_conditions
);
274 push_slist(&cond_false_stack
, false_states
);
277 void __use_previously_stored_false_states()
279 del_slist(&cur_slist
);
280 cur_slist
= pop_slist(&pre_cond_stack
);
283 void __use_cond_true_states()
285 __use_cond_stack(&cond_true_stack
);
288 void __use_cond_false_states()
290 __use_cond_stack(&cond_false_stack
);
293 void __negate_cond_stacks()
295 struct state_list
*old_false
, *old_true
;
297 old_false
= pop_slist(&cond_false_stack
);
298 old_true
= pop_slist(&cond_true_stack
);
300 overwrite_slist(old_false
, &cur_slist
);
302 push_slist(&cond_false_stack
, old_true
);
303 push_slist(&cond_true_stack
, old_false
);
306 void __and_cond_states()
308 and_slist_stack(&cond_true_stack
);
309 or_slist_stack(&cond_false_stack
);
312 void __or_cond_states()
314 or_slist_stack(&cond_true_stack
);
315 and_slist_stack(&cond_false_stack
);
318 void __save_pre_cond_states()
320 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
323 void __pop_pre_cond_states()
325 struct state_list
*tmp
;
327 tmp
= pop_slist(&pre_cond_stack
);
331 void __use_false_only_stack()
333 struct state_list
*slist
;
335 slist
= pop_slist(&false_only_stack
);
336 overwrite_slist(slist
, &cur_slist
);
340 void __pop_false_only_stack()
342 struct state_list
*slist
;
344 slist
= pop_slist(&false_only_stack
);
348 void __use_cond_states()
350 struct state_list
*pre
, *pre_clone
, *true_states
, *false_states
;
352 pre
= pop_slist(&pre_cond_stack
);
353 pre_clone
= clone_slist(pre
);
355 true_states
= pop_slist(&cond_true_stack
);
356 overwrite_slist(true_states
, &pre
);
357 /* we use the true states right away */
358 del_slist(&cur_slist
);
362 false_states
= pop_slist(&cond_false_stack
);
363 push_slist(&false_only_stack
, clone_slist(false_states
));
364 overwrite_slist(false_states
, &pre_clone
);
365 push_slist(&false_stack
, pre_clone
);
368 void __push_true_states()
370 push_slist(&true_stack
, clone_slist(cur_slist
));
373 void __use_false_states()
375 del_slist(&cur_slist
);
376 cur_slist
= pop_slist(&false_stack
);
379 void __pop_false_states()
381 struct state_list
*slist
;
383 slist
= pop_slist(&false_stack
);
387 void __merge_false_states()
389 struct state_list
*slist
;
391 slist
= pop_slist(&false_stack
);
392 merge_slist(&cur_slist
, slist
);
396 void __merge_true_states()
398 struct state_list
*slist
;
400 slist
= pop_slist(&true_stack
);
401 merge_slist(&cur_slist
, slist
);
405 void __push_continues()
407 push_slist(&continue_stack
, NULL
);
410 void __pop_continues()
412 struct state_list
*slist
;
414 slist
= pop_slist(&continue_stack
);
418 void __process_continues()
420 struct state_list
*slist
;
422 slist
= pop_slist(&continue_stack
);
424 slist
= clone_slist(cur_slist
);
426 merge_slist(&slist
, cur_slist
);
428 push_slist(&continue_stack
, slist
);
431 void __merge_continues()
433 struct state_list
*slist
;
435 slist
= pop_slist(&continue_stack
);
436 merge_slist(&cur_slist
, slist
);
442 push_slist(&break_stack
, NULL
);
445 void __process_breaks()
447 struct state_list
*slist
;
449 slist
= pop_slist(&break_stack
);
451 slist
= clone_slist(cur_slist
);
453 merge_slist(&slist
, cur_slist
);
455 push_slist(&break_stack
, slist
);
458 void __merge_breaks()
460 struct state_list
*slist
;
462 slist
= pop_slist(&break_stack
);
463 merge_slist(&cur_slist
, slist
);
469 del_slist(&cur_slist
);
470 cur_slist
= pop_slist(&break_stack
);
473 void __save_switch_states()
475 push_slist(&switch_stack
, clone_slist(cur_slist
));
478 void __merge_switches()
480 struct state_list
*slist
;
482 slist
= pop_slist(&switch_stack
);
483 merge_slist(&cur_slist
, slist
);
484 push_slist(&switch_stack
, slist
);
487 void __pop_switches()
489 struct state_list
*slist
;
491 slist
= pop_slist(&switch_stack
);
495 void __push_default()
497 push_slist(&default_stack
, NULL
);
502 set_state_stack(&default_stack
, "has_default", 0, NULL
, &true_state
);
507 struct state_list
*slist
;
509 slist
= pop_slist(&default_stack
);
517 static struct named_slist
*alloc_named_slist(const char *name
,
518 struct state_list
*slist
)
520 struct named_slist
*named_slist
= __alloc_named_slist(0);
522 named_slist
->name
= (char *)name
;
523 named_slist
->slist
= slist
;
527 void __save_gotos(const char *name
)
529 struct state_list
**slist
;
531 slist
= get_slist_from_named_stack(goto_stack
, name
);
533 merge_slist(slist
, cur_slist
);
536 struct state_list
*slist
;
537 struct named_slist
*named_slist
;
539 slist
= clone_slist(cur_slist
);
540 named_slist
= alloc_named_slist(name
, slist
);
541 add_ptr_list(&goto_stack
, named_slist
);
545 void __merge_gotos(const char *name
)
547 struct state_list
**slist
;
549 slist
= get_slist_from_named_stack(goto_stack
, name
);
551 merge_slist(&cur_slist
, *slist
);