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"
31 #include "smatch_extra.h"
33 struct smatch_state undefined
= { .name
= "undefined" };
34 struct smatch_state merged
= { .name
= "merged" };
35 struct smatch_state true_state
= { .name
= "true" };
36 struct smatch_state false_state
= { .name
= "false" };
38 static struct state_list
*cur_slist
; /* current states */
40 static struct state_list_stack
*true_stack
; /* states after a t/f branch */
41 static struct state_list_stack
*false_stack
;
42 static struct state_list_stack
*pre_cond_stack
; /* states before a t/f branch */
44 static struct state_list_stack
*cond_true_stack
; /* states affected by a branch */
45 static struct state_list_stack
*cond_false_stack
;
48 struct state_list
*__fake_cur_slist
= NULL
;
49 int __fake_conditions
= 0;
50 struct state_list
*__fake_cond_true
= NULL
;
51 struct state_list
*__fake_cond_false
= NULL
;
53 static struct state_list_stack
*break_stack
;
54 static struct state_list_stack
*switch_stack
;
55 static struct range_list_stack
*remaining_cases
;
56 static struct state_list_stack
*default_stack
;
57 static struct state_list_stack
*continue_stack
;
58 static struct state_list_stack
*false_only_stack
;
60 static struct named_stack
*goto_stack
;
62 struct state_list_stack
*implied_pools
;
66 void __print_cur_slist()
68 __print_slist(cur_slist
);
71 static int unreachable()
73 static int reset_warnings
= 1;
80 if (reset_warnings
|| debug_states
)
81 smatch_msg("info: ignoring unreachable code.");
86 void set_state(const char *name
, int owner
, struct symbol
*sym
,
87 struct smatch_state
*state
)
93 struct smatch_state
*s
;
95 s
= get_state(name
, owner
, sym
);
97 printf("%d new state. name='%s' owner=%d: %s\n",
98 get_lineno(), name
, owner
, show_state(state
));
100 printf("%d state change name='%s' owner=%d: %s => %s\n",
101 get_lineno(), name
, owner
, show_state(s
),
105 if (owner
!= -1 && unreachable())
109 set_state_slist(&__fake_cur_slist
, name
, owner
, sym
, state
);
113 set_state_slist(&cur_slist
, name
, owner
, sym
, state
);
115 if (cond_true_stack
) {
116 set_state_stack(&cond_true_stack
, name
, owner
, sym
, state
);
117 set_state_stack(&cond_false_stack
, name
, owner
, sym
, state
);
121 void __set_state(struct sm_state
*sm
)
124 struct smatch_state
*s
;
126 s
= get_state(sm
->name
, sm
->owner
, sm
->sym
);
128 printf("%d new state. name='%s' owner=%d: %s\n",
129 get_lineno(), sm
->name
, sm
->owner
, show_state(sm
->state
));
131 printf("%d state change name='%s' owner=%d: %s => %s\n",
132 get_lineno(), sm
->name
, sm
->owner
, show_state(s
),
133 show_state(sm
->state
));
139 overwrite_sm_state(&cur_slist
, sm
);
141 if (cond_true_stack
) {
142 overwrite_sm_state_stack(&cond_true_stack
, sm
);
143 overwrite_sm_state_stack(&cond_false_stack
, sm
);
147 struct smatch_state
*get_state(const char *name
, int owner
, struct symbol
*sym
)
149 return get_state_slist(cur_slist
, name
, owner
, sym
);
152 struct state_list
*get_possible_states(const char *name
, int owner
,
155 struct sm_state
*sms
;
157 sms
= get_sm_state_slist(cur_slist
, name
, owner
, sym
);
159 return sms
->possible
;
163 struct sm_state
*get_sm_state(const char *name
, int owner
, struct symbol
*sym
)
165 return get_sm_state_slist(cur_slist
, name
, owner
, sym
);
168 void delete_state(const char *name
, int owner
, struct symbol
*sym
)
170 delete_state_slist(&cur_slist
, name
, owner
, sym
);
173 struct state_list
*get_all_states(int owner
)
175 struct state_list
*slist
= NULL
;
176 struct sm_state
*tmp
;
178 FOR_EACH_PTR(cur_slist
, tmp
) {
179 if (tmp
->owner
== owner
) {
180 add_ptr_list(&slist
, tmp
);
182 } END_FOR_EACH_PTR(tmp
);
194 struct state_list
*__get_cur_slist()
199 void set_true_false_states(const char *name
, int owner
, struct symbol
*sym
,
200 struct smatch_state
*true_state
,
201 struct smatch_state
*false_state
)
204 struct smatch_state
*tmp
;
206 tmp
= get_state(name
, owner
, sym
);
207 SM_DEBUG("%d set_true_false '%s'. Was %s. Now T:%s F:%s\n",
208 get_lineno(), name
, show_state(tmp
),
209 show_state(true_state
), show_state(false_state
));
215 if (__fake_conditions
) {
217 set_state_slist(&__fake_cond_true
, name
, owner
, sym
, true_state
);
219 set_state_slist(&__fake_cond_false
, name
, owner
, sym
, false_state
);
223 if (!cond_false_stack
|| !cond_true_stack
) {
224 printf("Error: missing true/false stacks\n");
229 set_state_slist(&cur_slist
, name
, owner
, sym
, true_state
);
230 set_state_stack(&cond_true_stack
, name
, owner
, sym
, true_state
);
233 set_state_stack(&cond_false_stack
, name
, owner
, sym
, false_state
);
236 void __set_true_false_sm(struct sm_state
*true_state
,
237 struct sm_state
*false_state
)
242 if (!cond_false_stack
|| !cond_true_stack
) {
243 printf("Error: missing true/false stacks\n");
248 overwrite_sm_state(&cur_slist
, true_state
);
249 overwrite_sm_state_stack(&cond_true_stack
, true_state
);
252 overwrite_sm_state_stack(&cond_false_stack
, false_state
);
257 free_slist(&cur_slist
);
260 void __match_nullify_path_hook(const char *fn
, struct expression
*expr
,
266 * At the start of every function we mark the path
267 * as unnull. That there is always at least one state
268 * in the cur_slist until nullify_path is called. This
269 * is used in merge_slist() for the first null check.
272 void __unnullify_path()
274 set_state("unnull_path", -1, NULL
, &true_state
);
284 void clear_all_states()
286 struct named_slist
*named_slist
;
289 free_stack_and_slists(&true_stack
);
290 free_stack_and_slists(&false_stack
);
291 free_stack_and_slists(&false_only_stack
);
292 free_stack_and_slists(&pre_cond_stack
);
293 free_stack_and_slists(&cond_true_stack
);
294 free_stack_and_slists(&cond_false_stack
);
295 free_stack_and_slists(&break_stack
);
296 free_stack_and_slists(&switch_stack
);
297 free_stack_and_slists(&continue_stack
);
298 free_stack_and_slists(&implied_pools
);
300 FOR_EACH_PTR(goto_stack
, named_slist
) {
301 free_slist(&named_slist
->slist
);
302 } END_FOR_EACH_PTR(named_slist
);
303 __free_ptr_list((struct ptr_list
**)&goto_stack
);
304 free_every_single_sm_state();
308 void __push_cond_stacks()
310 push_slist(&cond_true_stack
, NULL
);
311 push_slist(&cond_false_stack
, NULL
);
315 * This combines the pre cond states with either the true or false states.
317 * a = kmalloc() ; if (a !! foo(a)
318 * In the pre state a is possibly null. In the true state it is non null.
319 * In the false state it is null. Combine the pre and the false to get
320 * that when we call 'foo', 'a' is null.
323 static void __use_cond_stack(struct state_list_stack
**stack
)
325 struct state_list
*slist
;
327 free_slist(&cur_slist
);
329 cur_slist
= pop_slist(&pre_cond_stack
);
330 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
332 slist
= pop_slist(stack
);
333 overwrite_slist(slist
, &cur_slist
);
334 push_slist(stack
, slist
);
337 void __save_false_states_for_later()
339 struct state_list
*pre_conditions
;
340 struct state_list
*false_states
;
341 struct state_list
*tmp
;
343 pre_conditions
= pop_slist(&pre_cond_stack
);
344 false_states
= pop_slist(&cond_false_stack
);
345 tmp
= clone_slist(pre_conditions
);
347 overwrite_slist(false_states
, &tmp
);
349 push_slist(&pre_cond_stack
, tmp
);
350 push_slist(&pre_cond_stack
, pre_conditions
);
351 push_slist(&cond_false_stack
, false_states
);
354 void __use_previously_stored_false_states()
356 free_slist(&cur_slist
);
357 cur_slist
= pop_slist(&pre_cond_stack
);
360 void __use_cond_true_states()
362 __use_cond_stack(&cond_true_stack
);
365 void __use_cond_false_states()
367 __use_cond_stack(&cond_false_stack
);
370 void __negate_cond_stacks()
372 struct state_list
*old_false
, *old_true
;
374 old_false
= pop_slist(&cond_false_stack
);
375 old_true
= pop_slist(&cond_true_stack
);
377 overwrite_slist(old_false
, &cur_slist
);
379 push_slist(&cond_false_stack
, old_true
);
380 push_slist(&cond_true_stack
, old_false
);
383 void __and_cond_states()
385 and_slist_stack(&cond_true_stack
);
386 or_slist_stack(&pre_cond_stack
, cur_slist
, &cond_false_stack
);
389 void __or_cond_states()
391 or_slist_stack(&pre_cond_stack
, cur_slist
, &cond_true_stack
);
392 and_slist_stack(&cond_false_stack
);
395 void __save_pre_cond_states()
397 push_slist(&pre_cond_stack
, clone_slist(cur_slist
));
400 void __pop_pre_cond_states()
402 struct state_list
*tmp
;
404 tmp
= pop_slist(&pre_cond_stack
);
408 void __use_false_only_stack()
410 struct state_list
*slist
;
412 slist
= pop_slist(&false_only_stack
);
413 overwrite_slist(slist
, &cur_slist
);
417 void __pop_false_only_stack()
419 struct state_list
*slist
;
421 slist
= pop_slist(&false_only_stack
);
425 void __use_cond_states()
427 struct state_list
*pre
, *pre_clone
, *true_states
, *false_states
;
429 pre
= pop_slist(&pre_cond_stack
);
430 pre_clone
= clone_slist(pre
);
432 true_states
= pop_slist(&cond_true_stack
);
433 overwrite_slist(true_states
, &pre
);
434 /* we use the true states right away */
435 free_slist(&cur_slist
);
439 false_states
= pop_slist(&cond_false_stack
);
440 push_slist(&false_only_stack
, clone_slist(false_states
));
441 overwrite_slist(false_states
, &pre_clone
);
442 push_slist(&false_stack
, pre_clone
);
445 void __push_true_states()
447 push_slist(&true_stack
, clone_slist(cur_slist
));
450 void __use_false_states()
452 free_slist(&cur_slist
);
453 cur_slist
= pop_slist(&false_stack
);
456 void __pop_false_states()
458 struct state_list
*slist
;
460 slist
= pop_slist(&false_stack
);
464 void __merge_false_states()
466 struct state_list
*slist
;
468 slist
= pop_slist(&false_stack
);
469 merge_slist(&cur_slist
, slist
);
473 void __merge_true_states()
475 struct state_list
*slist
;
477 slist
= pop_slist(&true_stack
);
478 merge_slist(&cur_slist
, slist
);
482 void __push_continues()
484 push_slist(&continue_stack
, NULL
);
487 void __pop_continues()
489 struct state_list
*slist
;
491 slist
= pop_slist(&continue_stack
);
495 void __process_continues()
497 struct state_list
*slist
;
499 slist
= pop_slist(&continue_stack
);
501 slist
= clone_slist(cur_slist
);
503 merge_slist(&slist
, cur_slist
);
505 push_slist(&continue_stack
, slist
);
508 static int top_slist_empty(struct state_list_stack
**stack
)
510 struct state_list
*tmp
;
513 tmp
= pop_slist(stack
);
516 push_slist(stack
, tmp
);
520 /* a silly loop does this: while(i--) { return; } */
521 void __warn_on_silly_pre_loops()
523 if (!__path_is_null())
525 if (!top_slist_empty(&continue_stack
))
527 if (!top_slist_empty(&break_stack
))
529 /* if the path was nullified before the loop, then we already
530 printed an error earlier */
531 if (top_slist_empty(&false_stack
))
533 smatch_msg("info: loop could be replaced with if statement.");
536 void __merge_continues()
538 struct state_list
*slist
;
540 slist
= pop_slist(&continue_stack
);
541 merge_slist(&cur_slist
, slist
);
547 push_slist(&break_stack
, NULL
);
550 void __process_breaks()
552 struct state_list
*slist
;
554 slist
= pop_slist(&break_stack
);
556 slist
= clone_slist(cur_slist
);
558 merge_slist(&slist
, cur_slist
);
560 push_slist(&break_stack
, slist
);
563 void __merge_breaks()
565 struct state_list
*slist
;
567 slist
= pop_slist(&break_stack
);
568 merge_slist(&cur_slist
, slist
);
574 free_slist(&cur_slist
);
575 cur_slist
= pop_slist(&break_stack
);
578 void __save_switch_states(struct expression
*switch_expr
)
580 push_range_list(&remaining_cases
, __get_implied_values(switch_expr
));
581 push_slist(&switch_stack
, clone_slist(cur_slist
));
584 void __merge_switches(struct expression
*switch_expr
, struct expression
*case_expr
)
586 struct state_list
*slist
;
587 struct state_list
*implied_slist
;
589 slist
= pop_slist(&switch_stack
);
590 implied_slist
= __implied_case_slist(switch_expr
, case_expr
, &remaining_cases
, &slist
);
591 merge_slist(&cur_slist
, implied_slist
);
592 free_slist(&implied_slist
);
593 push_slist(&switch_stack
, slist
);
596 void __pop_switches()
598 struct state_list
*slist
;
600 pop_range_list(&remaining_cases
);
601 slist
= pop_slist(&switch_stack
);
605 void __push_default()
607 push_slist(&default_stack
, NULL
);
612 set_state_stack(&default_stack
, "has_default", 0, NULL
, &true_state
);
617 struct state_list
*slist
;
619 slist
= pop_slist(&default_stack
);
627 static struct named_slist
*alloc_named_slist(const char *name
,
628 struct state_list
*slist
)
630 struct named_slist
*named_slist
= __alloc_named_slist(0);
632 named_slist
->name
= (char *)name
;
633 named_slist
->slist
= slist
;
637 void __save_gotos(const char *name
)
639 struct state_list
**slist
;
640 struct state_list
*clone
;
642 slist
= get_slist_from_named_stack(goto_stack
, name
);
644 clone
= clone_slist(cur_slist
);
645 merge_slist(slist
, clone
);
649 struct named_slist
*named_slist
;
651 clone
= clone_slist(cur_slist
);
652 named_slist
= alloc_named_slist(name
, clone
);
653 add_ptr_list(&goto_stack
, named_slist
);
657 void __merge_gotos(const char *name
)
659 struct state_list
**slist
;
661 slist
= get_slist_from_named_stack(goto_stack
, name
);
663 merge_slist(&cur_slist
, *slist
);