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("info: 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 void __set_state(struct sm_state
*sm
)
111 struct smatch_state
*s
;
113 s
= get_state(sm
->name
, sm
->owner
, sm
->sym
);
115 printf("%d new state. name='%s' owner=%d: %s\n",
116 get_lineno(), sm
->name
, sm
->owner
, show_state(sm
->state
));
118 printf("%d state change name='%s' owner=%d: %s => %s\n",
119 get_lineno(), sm
->name
, sm
->owner
, show_state(s
),
120 show_state(sm
->state
));
126 overwrite_sm_state(&cur_slist
, sm
);
128 if (cond_true_stack
) {
129 overwrite_sm_state_stack(&cond_true_stack
, sm
);
130 overwrite_sm_state_stack(&cond_false_stack
, sm
);
134 struct smatch_state
*get_state(const char *name
, int owner
, struct symbol
*sym
)
136 return get_state_slist(cur_slist
, name
, owner
, sym
);
139 struct state_list
*get_possible_states(const char *name
, int owner
,
142 struct sm_state
*sms
;
144 sms
= get_sm_state_slist(cur_slist
, name
, owner
, sym
);
146 return sms
->possible
;
150 struct sm_state
*get_sm_state(const char *name
, int owner
, struct symbol
*sym
)
152 return get_sm_state_slist(cur_slist
, name
, owner
, sym
);
155 void delete_state(const char *name
, int owner
, struct symbol
*sym
)
157 delete_state_slist(&cur_slist
, name
, owner
, sym
);
160 struct state_list
*get_all_states(int owner
)
162 struct state_list
*slist
= NULL
;
163 struct sm_state
*tmp
;
165 FOR_EACH_PTR(cur_slist
, tmp
) {
166 if (tmp
->owner
== owner
) {
167 add_ptr_list(&slist
, tmp
);
169 } END_FOR_EACH_PTR(tmp
);
181 struct state_list
*__get_cur_slist()
186 void set_true_false_states(const char *name
, int owner
, struct symbol
*sym
,
187 struct smatch_state
*true_state
,
188 struct smatch_state
*false_state
)
191 struct smatch_state
*tmp
;
193 tmp
= get_state(name
, owner
, sym
);
194 SM_DEBUG("%d set_true_false '%s'. Was %s. Now T:%s F:%s\n",
195 get_lineno(), name
, show_state(tmp
),
196 show_state(true_state
), show_state(false_state
));
202 if (!cond_false_stack
|| !cond_true_stack
) {
203 printf("Error: missing true/false stacks\n");
208 set_state_slist(&cur_slist
, name
, owner
, sym
, true_state
);
209 set_state_stack(&cond_true_stack
, name
, owner
, sym
, true_state
);
212 set_state_stack(&cond_false_stack
, name
, owner
, sym
, false_state
);
215 void __set_true_false_sm(struct sm_state
*true_state
,
216 struct sm_state
*false_state
)
221 if (!cond_false_stack
|| !cond_true_stack
) {
222 printf("Error: missing true/false stacks\n");
227 overwrite_sm_state(&cur_slist
, true_state
);
228 overwrite_sm_state_stack(&cond_true_stack
, true_state
);
231 overwrite_sm_state_stack(&cond_false_stack
, false_state
);
236 free_slist(&cur_slist
);
239 void __match_nullify_path_hook(const char *fn
, struct expression
*expr
,
245 * At the start of every function we mark the path
246 * as unnull. That there is always at least one state
247 * in the cur_slist until nullify_path is called. This
248 * is used in merge_slist() for the first null check.
251 void __unnullify_path()
253 set_state("unnull_path", -1, NULL
, &true_state
);
263 void clear_all_states()
265 struct named_slist
*named_slist
;
268 free_stack_and_slists(&true_stack
);
269 free_stack_and_slists(&false_stack
);
270 free_stack_and_slists(&false_only_stack
);
271 free_stack_and_slists(&pre_cond_stack
);
272 free_stack_and_slists(&cond_true_stack
);
273 free_stack_and_slists(&cond_false_stack
);
274 free_stack_and_slists(&break_stack
);
275 free_stack_and_slists(&switch_stack
);
276 free_stack_and_slists(&continue_stack
);
277 free_stack_and_slists(&implied_pools
);
279 FOR_EACH_PTR(goto_stack
, named_slist
) {
280 free_slist(&named_slist
->slist
);
281 } END_FOR_EACH_PTR(named_slist
);
282 __free_ptr_list((struct ptr_list
**)&goto_stack
);
283 free_every_single_sm_state();
287 void __push_cond_stacks()
289 push_slist(&cond_true_stack
, NULL
);
290 push_slist(&cond_false_stack
, NULL
);
294 * This combines the pre cond states with either the true or false states.
296 * a = kmalloc() ; if (a !! foo(a)
297 * In the pre state a is possibly null. In the true state it is non null.
298 * In the false state it is null. Combine the pre and the false to get
299 * that when we call 'foo', 'a' is null.
302 static void __use_cond_stack(struct state_list_stack
**stack
)
304 struct state_list
*slist
;
306 free_slist(&cur_slist
);
308 cur_slist
= pop_slist(&pre_cond_stack
);
309 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
311 slist
= pop_slist(stack
);
312 overwrite_slist(slist
, &cur_slist
);
313 push_slist(stack
, slist
);
316 void __save_false_states_for_later()
318 struct state_list
*pre_conditions
;
319 struct state_list
*false_states
;
320 struct state_list
*tmp
;
322 pre_conditions
= pop_slist(&pre_cond_stack
);
323 false_states
= pop_slist(&cond_false_stack
);
324 tmp
= clone_slist(pre_conditions
);
326 overwrite_slist(false_states
, &tmp
);
328 push_slist(&pre_cond_stack
, tmp
);
329 push_slist(&pre_cond_stack
, pre_conditions
);
330 push_slist(&cond_false_stack
, false_states
);
333 void __use_previously_stored_false_states()
335 free_slist(&cur_slist
);
336 cur_slist
= pop_slist(&pre_cond_stack
);
339 void __use_cond_true_states()
341 __use_cond_stack(&cond_true_stack
);
344 void __use_cond_false_states()
346 __use_cond_stack(&cond_false_stack
);
349 void __negate_cond_stacks()
351 struct state_list
*old_false
, *old_true
;
353 old_false
= pop_slist(&cond_false_stack
);
354 old_true
= pop_slist(&cond_true_stack
);
356 overwrite_slist(old_false
, &cur_slist
);
358 push_slist(&cond_false_stack
, old_true
);
359 push_slist(&cond_true_stack
, old_false
);
362 void __and_cond_states()
364 and_slist_stack(&cond_true_stack
);
365 or_slist_stack(&pre_cond_stack
, cur_slist
, &cond_false_stack
);
368 void __or_cond_states()
370 or_slist_stack(&pre_cond_stack
, cur_slist
, &cond_true_stack
);
371 and_slist_stack(&cond_false_stack
);
374 void __save_pre_cond_states()
376 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
379 void __pop_pre_cond_states()
381 struct state_list
*tmp
;
383 tmp
= pop_slist(&pre_cond_stack
);
387 void __use_false_only_stack()
389 struct state_list
*slist
;
391 slist
= pop_slist(&false_only_stack
);
392 overwrite_slist(slist
, &cur_slist
);
396 void __pop_false_only_stack()
398 struct state_list
*slist
;
400 slist
= pop_slist(&false_only_stack
);
404 void __use_cond_states()
406 struct state_list
*pre
, *pre_clone
, *true_states
, *false_states
;
408 pre
= pop_slist(&pre_cond_stack
);
409 pre_clone
= clone_slist(pre
);
411 true_states
= pop_slist(&cond_true_stack
);
412 overwrite_slist(true_states
, &pre
);
413 /* we use the true states right away */
414 free_slist(&cur_slist
);
418 false_states
= pop_slist(&cond_false_stack
);
419 push_slist(&false_only_stack
, clone_slist(false_states
));
420 overwrite_slist(false_states
, &pre_clone
);
421 push_slist(&false_stack
, pre_clone
);
424 void __push_true_states()
426 push_slist(&true_stack
, clone_slist(cur_slist
));
429 void __use_false_states()
431 free_slist(&cur_slist
);
432 cur_slist
= pop_slist(&false_stack
);
435 void __pop_false_states()
437 struct state_list
*slist
;
439 slist
= pop_slist(&false_stack
);
443 void __merge_false_states()
445 struct state_list
*slist
;
447 slist
= pop_slist(&false_stack
);
448 merge_slist(&cur_slist
, slist
);
452 void __merge_true_states()
454 struct state_list
*slist
;
456 slist
= pop_slist(&true_stack
);
457 merge_slist(&cur_slist
, slist
);
461 void __push_continues()
463 push_slist(&continue_stack
, NULL
);
466 void __pop_continues()
468 struct state_list
*slist
;
470 slist
= pop_slist(&continue_stack
);
474 void __process_continues()
476 struct state_list
*slist
;
478 slist
= pop_slist(&continue_stack
);
480 slist
= clone_slist(cur_slist
);
482 merge_slist(&slist
, cur_slist
);
484 push_slist(&continue_stack
, slist
);
487 static int top_slist_empty(struct state_list_stack
**stack
)
489 struct state_list
*tmp
;
492 tmp
= pop_slist(stack
);
495 push_slist(stack
, tmp
);
499 /* a silly loop does this: while(i--) { return; } */
500 void __warn_on_silly_pre_loops()
502 if (!__path_is_null())
504 if (!top_slist_empty(&continue_stack
))
506 if (!top_slist_empty(&break_stack
))
508 /* if the path was nullified before the loop, then we already
509 printed an error earlier */
510 if (top_slist_empty(&false_stack
))
512 smatch_msg("info: loop could be replaced with if statement.");
515 void __merge_continues()
517 struct state_list
*slist
;
519 slist
= pop_slist(&continue_stack
);
520 merge_slist(&cur_slist
, slist
);
526 push_slist(&break_stack
, NULL
);
529 void __process_breaks()
531 struct state_list
*slist
;
533 slist
= pop_slist(&break_stack
);
535 slist
= clone_slist(cur_slist
);
537 merge_slist(&slist
, cur_slist
);
539 push_slist(&break_stack
, slist
);
542 void __merge_breaks()
544 struct state_list
*slist
;
546 slist
= pop_slist(&break_stack
);
547 merge_slist(&cur_slist
, slist
);
553 free_slist(&cur_slist
);
554 cur_slist
= pop_slist(&break_stack
);
557 void __save_switch_states()
559 push_slist(&switch_stack
, clone_slist(cur_slist
));
562 void __merge_switches()
564 struct state_list
*slist
;
566 slist
= pop_slist(&switch_stack
);
567 merge_slist(&cur_slist
, slist
);
568 push_slist(&switch_stack
, slist
);
571 void __pop_switches()
573 struct state_list
*slist
;
575 slist
= pop_slist(&switch_stack
);
579 void __push_default()
581 push_slist(&default_stack
, NULL
);
586 set_state_stack(&default_stack
, "has_default", 0, NULL
, &true_state
);
591 struct state_list
*slist
;
593 slist
= pop_slist(&default_stack
);
601 static struct named_slist
*alloc_named_slist(const char *name
,
602 struct state_list
*slist
)
604 struct named_slist
*named_slist
= __alloc_named_slist(0);
606 named_slist
->name
= (char *)name
;
607 named_slist
->slist
= slist
;
611 void __save_gotos(const char *name
)
613 struct state_list
**slist
;
615 slist
= get_slist_from_named_stack(goto_stack
, name
);
617 merge_slist(slist
, cur_slist
);
620 struct state_list
*slist
;
621 struct named_slist
*named_slist
;
623 slist
= clone_slist(cur_slist
);
624 named_slist
= alloc_named_slist(name
, slist
);
625 add_ptr_list(&goto_stack
, named_slist
);
629 void __merge_gotos(const char *name
)
631 struct state_list
**slist
;
633 slist
= get_slist_from_named_stack(goto_stack
, name
);
635 merge_slist(&cur_slist
, *slist
);