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
;
47 struct state_list
*__fake_cur_slist
= NULL
;
48 int __fake_conditions
= 0;
49 struct state_list
*__fake_cond_true
= NULL
;
50 struct state_list
*__fake_cond_false
= NULL
;
52 static struct state_list_stack
*break_stack
;
53 static struct state_list_stack
*switch_stack
;
54 static struct state_list_stack
*default_stack
;
55 static struct state_list_stack
*continue_stack
;
56 static struct state_list_stack
*false_only_stack
;
58 static struct named_stack
*goto_stack
;
60 struct state_list_stack
*implied_pools
;
64 void __print_cur_slist()
66 __print_slist(cur_slist
);
69 static int unreachable()
71 static int reset_warnings
= 1;
78 if (reset_warnings
|| debug_states
)
79 smatch_msg("info: ignoring unreachable code.");
84 void set_state(const char *name
, int owner
, struct symbol
*sym
,
85 struct smatch_state
*state
)
91 struct smatch_state
*s
;
93 s
= get_state(name
, owner
, sym
);
95 printf("%d new state. name='%s' owner=%d: %s\n",
96 get_lineno(), name
, owner
, show_state(state
));
98 printf("%d state change name='%s' owner=%d: %s => %s\n",
99 get_lineno(), name
, owner
, show_state(s
),
103 if (owner
!= -1 && unreachable())
107 set_state_slist(&__fake_cur_slist
, name
, owner
, sym
, state
);
111 set_state_slist(&cur_slist
, name
, owner
, sym
, state
);
113 if (cond_true_stack
) {
114 set_state_stack(&cond_true_stack
, name
, owner
, sym
, state
);
115 set_state_stack(&cond_false_stack
, name
, owner
, sym
, state
);
119 void __set_state(struct sm_state
*sm
)
122 struct smatch_state
*s
;
124 s
= get_state(sm
->name
, sm
->owner
, sm
->sym
);
126 printf("%d new state. name='%s' owner=%d: %s\n",
127 get_lineno(), sm
->name
, sm
->owner
, show_state(sm
->state
));
129 printf("%d state change name='%s' owner=%d: %s => %s\n",
130 get_lineno(), sm
->name
, sm
->owner
, show_state(s
),
131 show_state(sm
->state
));
137 overwrite_sm_state(&cur_slist
, sm
);
139 if (cond_true_stack
) {
140 overwrite_sm_state_stack(&cond_true_stack
, sm
);
141 overwrite_sm_state_stack(&cond_false_stack
, sm
);
145 struct smatch_state
*get_state(const char *name
, int owner
, struct symbol
*sym
)
147 return get_state_slist(cur_slist
, name
, owner
, sym
);
150 struct state_list
*get_possible_states(const char *name
, int owner
,
153 struct sm_state
*sms
;
155 sms
= get_sm_state_slist(cur_slist
, name
, owner
, sym
);
157 return sms
->possible
;
161 struct sm_state
*get_sm_state(const char *name
, int owner
, struct symbol
*sym
)
163 return get_sm_state_slist(cur_slist
, name
, owner
, sym
);
166 void delete_state(const char *name
, int owner
, struct symbol
*sym
)
168 delete_state_slist(&cur_slist
, name
, owner
, sym
);
171 struct state_list
*get_all_states(int owner
)
173 struct state_list
*slist
= NULL
;
174 struct sm_state
*tmp
;
176 FOR_EACH_PTR(cur_slist
, tmp
) {
177 if (tmp
->owner
== owner
) {
178 add_ptr_list(&slist
, tmp
);
180 } END_FOR_EACH_PTR(tmp
);
192 struct state_list
*__get_cur_slist()
197 void set_true_false_states(const char *name
, int owner
, struct symbol
*sym
,
198 struct smatch_state
*true_state
,
199 struct smatch_state
*false_state
)
202 struct smatch_state
*tmp
;
204 tmp
= get_state(name
, owner
, sym
);
205 SM_DEBUG("%d set_true_false '%s'. Was %s. Now T:%s F:%s\n",
206 get_lineno(), name
, show_state(tmp
),
207 show_state(true_state
), show_state(false_state
));
213 if (__fake_conditions
) {
215 set_state_slist(&__fake_cond_true
, name
, owner
, sym
, true_state
);
217 set_state_slist(&__fake_cond_false
, name
, owner
, sym
, false_state
);
221 if (!cond_false_stack
|| !cond_true_stack
) {
222 printf("Error: missing true/false stacks\n");
227 set_state_slist(&cur_slist
, name
, owner
, sym
, true_state
);
228 set_state_stack(&cond_true_stack
, name
, owner
, sym
, true_state
);
231 set_state_stack(&cond_false_stack
, name
, owner
, sym
, false_state
);
234 void __set_true_false_sm(struct sm_state
*true_state
,
235 struct sm_state
*false_state
)
240 if (!cond_false_stack
|| !cond_true_stack
) {
241 printf("Error: missing true/false stacks\n");
246 overwrite_sm_state(&cur_slist
, true_state
);
247 overwrite_sm_state_stack(&cond_true_stack
, true_state
);
250 overwrite_sm_state_stack(&cond_false_stack
, false_state
);
255 free_slist(&cur_slist
);
258 void __match_nullify_path_hook(const char *fn
, struct expression
*expr
,
264 * At the start of every function we mark the path
265 * as unnull. That there is always at least one state
266 * in the cur_slist until nullify_path is called. This
267 * is used in merge_slist() for the first null check.
270 void __unnullify_path()
272 set_state("unnull_path", -1, NULL
, &true_state
);
282 void clear_all_states()
284 struct named_slist
*named_slist
;
287 free_stack_and_slists(&true_stack
);
288 free_stack_and_slists(&false_stack
);
289 free_stack_and_slists(&false_only_stack
);
290 free_stack_and_slists(&pre_cond_stack
);
291 free_stack_and_slists(&cond_true_stack
);
292 free_stack_and_slists(&cond_false_stack
);
293 free_stack_and_slists(&break_stack
);
294 free_stack_and_slists(&switch_stack
);
295 free_stack_and_slists(&continue_stack
);
296 free_stack_and_slists(&implied_pools
);
298 FOR_EACH_PTR(goto_stack
, named_slist
) {
299 free_slist(&named_slist
->slist
);
300 } END_FOR_EACH_PTR(named_slist
);
301 __free_ptr_list((struct ptr_list
**)&goto_stack
);
302 free_every_single_sm_state();
306 void __push_cond_stacks()
308 push_slist(&cond_true_stack
, NULL
);
309 push_slist(&cond_false_stack
, NULL
);
313 * This combines the pre cond states with either the true or false states.
315 * a = kmalloc() ; if (a !! foo(a)
316 * In the pre state a is possibly null. In the true state it is non null.
317 * In the false state it is null. Combine the pre and the false to get
318 * that when we call 'foo', 'a' is null.
321 static void __use_cond_stack(struct state_list_stack
**stack
)
323 struct state_list
*slist
;
325 free_slist(&cur_slist
);
327 cur_slist
= pop_slist(&pre_cond_stack
);
328 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
330 slist
= pop_slist(stack
);
331 overwrite_slist(slist
, &cur_slist
);
332 push_slist(stack
, slist
);
335 void __save_false_states_for_later()
337 struct state_list
*pre_conditions
;
338 struct state_list
*false_states
;
339 struct state_list
*tmp
;
341 pre_conditions
= pop_slist(&pre_cond_stack
);
342 false_states
= pop_slist(&cond_false_stack
);
343 tmp
= clone_slist(pre_conditions
);
345 overwrite_slist(false_states
, &tmp
);
347 push_slist(&pre_cond_stack
, tmp
);
348 push_slist(&pre_cond_stack
, pre_conditions
);
349 push_slist(&cond_false_stack
, false_states
);
352 void __use_previously_stored_false_states()
354 free_slist(&cur_slist
);
355 cur_slist
= pop_slist(&pre_cond_stack
);
358 void __use_cond_true_states()
360 __use_cond_stack(&cond_true_stack
);
363 void __use_cond_false_states()
365 __use_cond_stack(&cond_false_stack
);
368 void __negate_cond_stacks()
370 struct state_list
*old_false
, *old_true
;
372 old_false
= pop_slist(&cond_false_stack
);
373 old_true
= pop_slist(&cond_true_stack
);
375 overwrite_slist(old_false
, &cur_slist
);
377 push_slist(&cond_false_stack
, old_true
);
378 push_slist(&cond_true_stack
, old_false
);
381 void __and_cond_states()
383 and_slist_stack(&cond_true_stack
);
384 or_slist_stack(&pre_cond_stack
, cur_slist
, &cond_false_stack
);
387 void __or_cond_states()
389 or_slist_stack(&pre_cond_stack
, cur_slist
, &cond_true_stack
);
390 and_slist_stack(&cond_false_stack
);
393 void __save_pre_cond_states()
395 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
398 void __pop_pre_cond_states()
400 struct state_list
*tmp
;
402 tmp
= pop_slist(&pre_cond_stack
);
406 void __use_false_only_stack()
408 struct state_list
*slist
;
410 slist
= pop_slist(&false_only_stack
);
411 overwrite_slist(slist
, &cur_slist
);
415 void __pop_false_only_stack()
417 struct state_list
*slist
;
419 slist
= pop_slist(&false_only_stack
);
423 void __use_cond_states()
425 struct state_list
*pre
, *pre_clone
, *true_states
, *false_states
;
427 pre
= pop_slist(&pre_cond_stack
);
428 pre_clone
= clone_slist(pre
);
430 true_states
= pop_slist(&cond_true_stack
);
431 overwrite_slist(true_states
, &pre
);
432 /* we use the true states right away */
433 free_slist(&cur_slist
);
437 false_states
= pop_slist(&cond_false_stack
);
438 push_slist(&false_only_stack
, clone_slist(false_states
));
439 overwrite_slist(false_states
, &pre_clone
);
440 push_slist(&false_stack
, pre_clone
);
443 void __push_true_states()
445 push_slist(&true_stack
, clone_slist(cur_slist
));
448 void __use_false_states()
450 free_slist(&cur_slist
);
451 cur_slist
= pop_slist(&false_stack
);
454 void __pop_false_states()
456 struct state_list
*slist
;
458 slist
= pop_slist(&false_stack
);
462 void __merge_false_states()
464 struct state_list
*slist
;
466 slist
= pop_slist(&false_stack
);
467 merge_slist(&cur_slist
, slist
);
471 void __merge_true_states()
473 struct state_list
*slist
;
475 slist
= pop_slist(&true_stack
);
476 merge_slist(&cur_slist
, slist
);
480 void __push_continues()
482 push_slist(&continue_stack
, NULL
);
485 void __pop_continues()
487 struct state_list
*slist
;
489 slist
= pop_slist(&continue_stack
);
493 void __process_continues()
495 struct state_list
*slist
;
497 slist
= pop_slist(&continue_stack
);
499 slist
= clone_slist(cur_slist
);
501 merge_slist(&slist
, cur_slist
);
503 push_slist(&continue_stack
, slist
);
506 static int top_slist_empty(struct state_list_stack
**stack
)
508 struct state_list
*tmp
;
511 tmp
= pop_slist(stack
);
514 push_slist(stack
, tmp
);
518 /* a silly loop does this: while(i--) { return; } */
519 void __warn_on_silly_pre_loops()
521 if (!__path_is_null())
523 if (!top_slist_empty(&continue_stack
))
525 if (!top_slist_empty(&break_stack
))
527 /* if the path was nullified before the loop, then we already
528 printed an error earlier */
529 if (top_slist_empty(&false_stack
))
531 smatch_msg("info: loop could be replaced with if statement.");
534 void __merge_continues()
536 struct state_list
*slist
;
538 slist
= pop_slist(&continue_stack
);
539 merge_slist(&cur_slist
, slist
);
545 push_slist(&break_stack
, NULL
);
548 void __process_breaks()
550 struct state_list
*slist
;
552 slist
= pop_slist(&break_stack
);
554 slist
= clone_slist(cur_slist
);
556 merge_slist(&slist
, cur_slist
);
558 push_slist(&break_stack
, slist
);
561 void __merge_breaks()
563 struct state_list
*slist
;
565 slist
= pop_slist(&break_stack
);
566 merge_slist(&cur_slist
, slist
);
572 free_slist(&cur_slist
);
573 cur_slist
= pop_slist(&break_stack
);
576 void __save_switch_states()
578 push_slist(&switch_stack
, clone_slist(cur_slist
));
581 void __merge_switches(struct expression
*switch_expr
, struct expression
*case_expr
)
583 struct state_list
*slist
;
584 struct state_list
*implied_slist
;
586 slist
= pop_slist(&switch_stack
);
587 implied_slist
= __implied_case_slist(switch_expr
, case_expr
, &slist
);
588 merge_slist(&cur_slist
, implied_slist
);
589 free_slist(&implied_slist
);
590 push_slist(&switch_stack
, slist
);
593 void __pop_switches()
595 struct state_list
*slist
;
597 slist
= pop_slist(&switch_stack
);
601 void __push_default()
603 push_slist(&default_stack
, NULL
);
608 set_state_stack(&default_stack
, "has_default", 0, NULL
, &true_state
);
613 struct state_list
*slist
;
615 slist
= pop_slist(&default_stack
);
623 static struct named_slist
*alloc_named_slist(const char *name
,
624 struct state_list
*slist
)
626 struct named_slist
*named_slist
= __alloc_named_slist(0);
628 named_slist
->name
= (char *)name
;
629 named_slist
->slist
= slist
;
633 void __save_gotos(const char *name
)
635 struct state_list
**slist
;
636 struct state_list
*clone
;
638 slist
= get_slist_from_named_stack(goto_stack
, name
);
640 clone
= clone_slist(cur_slist
);
641 merge_slist(slist
, clone
);
645 struct named_slist
*named_slist
;
647 clone
= clone_slist(cur_slist
);
648 named_slist
= alloc_named_slist(name
, clone
);
649 add_ptr_list(&goto_stack
, named_slist
);
653 void __merge_gotos(const char *name
)
655 struct state_list
**slist
;
657 slist
= get_slist_from_named_stack(goto_stack
, name
);
659 merge_slist(&cur_slist
, *slist
);