2 * Copyright (C) 2006 Dan Carpenter.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
19 * You have a lists of states. kernel = locked, foo = NULL, ...
20 * When you hit an if {} else {} statement then you swap the list
21 * of states for a different list of states. The lists are stored
24 * At the beginning of this file there are list of the stacks that
25 * we use. Each function in this file does something to one of
28 * So the smatch_flow.c understands code but it doesn't understand states.
29 * smatch_flow calls functions in this file. This file calls functions
30 * in smatch_slist.c which just has boring generic plumbing for handling
31 * state lists. But really it's this file where all the magic happens.
37 #include "smatch_slist.h"
38 #include "smatch_extra.h"
40 struct smatch_state undefined
= { .name
= "undefined" };
41 struct smatch_state ghost
= { .name
= "ghost" };
42 struct smatch_state merged
= { .name
= "merged" };
43 struct smatch_state true_state
= { .name
= "true" };
44 struct smatch_state false_state
= { .name
= "false" };
46 static struct stree
*cur_stree
; /* current states */
48 static struct stree_stack
*true_stack
; /* states after a t/f branch */
49 static struct stree_stack
*false_stack
;
50 static struct stree_stack
*pre_cond_stack
; /* states before a t/f branch */
52 static struct stree_stack
*cond_true_stack
; /* states affected by a branch */
53 static struct stree_stack
*cond_false_stack
;
55 static struct stree_stack
*fake_cur_stree_stack
;
58 static struct stree_stack
*break_stack
;
59 static struct stree_stack
*switch_stack
;
60 static struct range_list_stack
*remaining_cases
;
61 static struct stree_stack
*default_stack
;
62 static struct stree_stack
*continue_stack
;
64 static struct named_stree_stack
*goto_stack
;
66 static struct ptr_list
*backup
;
70 void __print_cur_stree(void)
72 __print_stree(cur_stree
);
82 struct sm_state
*set_state(int owner
, const char *name
, struct symbol
*sym
, struct smatch_state
*state
)
90 sm_msg("Smatch Internal Error: cur_stree is read only.");
92 if (option_debug
|| strcmp(check_name(owner
), option_debug_check
) == 0) {
93 struct smatch_state
*s
;
95 s
= get_state(owner
, name
, sym
);
97 sm_msg("new state. name='%s' [%s] %s",
98 name
, check_name(owner
), show_state(state
));
100 sm_msg("state change name='%s' [%s] %s => %s",
101 name
, check_name(owner
), show_state(s
),
105 if (owner
!= -1 && unreachable())
108 if (fake_cur_stree_stack
)
109 set_state_stree_stack(&fake_cur_stree_stack
, owner
, name
, sym
, state
);
111 ret
= set_state_stree(&cur_stree
, owner
, name
, sym
, state
);
113 if (cond_true_stack
) {
114 set_state_stree_stack(&cond_true_stack
, owner
, name
, sym
, state
);
115 set_state_stree_stack(&cond_false_stack
, owner
, name
, sym
, state
);
120 struct sm_state
*set_state_expr(int owner
, struct expression
*expr
, struct smatch_state
*state
)
124 struct sm_state
*ret
= NULL
;
126 expr
= strip_expr(expr
);
127 name
= expr_to_var_sym(expr
, &sym
);
130 ret
= set_state(owner
, name
, sym
, state
);
136 void __swap_cur_stree(struct stree
*stree
)
138 free_stree(&cur_stree
);
142 void __push_fake_cur_stree(void)
144 push_stree(&fake_cur_stree_stack
, NULL
);
145 __save_pre_cond_states();
148 struct stree
*__pop_fake_cur_stree(void)
150 if (!fake_cur_stree_stack
)
151 sm_msg("INTERNAL error: popping too many fake cur strees.");
152 __use_pre_cond_states();
153 return pop_stree(&fake_cur_stree_stack
);
156 void __free_fake_cur_stree(void)
160 stree
= __pop_fake_cur_stree();
164 void __set_fake_cur_stree_fast(struct stree
*stree
)
166 push_stree(&pre_cond_stack
, cur_stree
);
171 void __pop_fake_cur_stree_fast(void)
173 cur_stree
= pop_stree(&pre_cond_stack
);
177 void __merge_stree_into_cur(struct stree
*stree
)
180 struct sm_state
*orig
;
181 struct sm_state
*merged
;
183 FOR_EACH_SM(stree
, sm
) {
184 orig
= get_sm_state(sm
->owner
, sm
->name
, sm
->sym
);
186 merged
= merge_sm_states(orig
, sm
);
190 } END_FOR_EACH_SM(sm
);
193 void __set_sm(struct sm_state
*sm
)
196 sm_msg("Smatch Internal Error: cur_stree is read only.");
199 strcmp(check_name(sm
->owner
), option_debug_check
) == 0) {
200 struct smatch_state
*s
;
202 s
= get_state(sm
->owner
, sm
->name
, sm
->sym
);
204 sm_msg("new state. name='%s' [%s] %s",
205 sm
->name
, check_name(sm
->owner
),
206 show_state(sm
->state
));
208 sm_msg("state change name='%s' [%s] %s => %s",
209 sm
->name
, check_name(sm
->owner
), show_state(s
),
210 show_state(sm
->state
));
216 if (fake_cur_stree_stack
)
217 overwrite_sm_state_stree_stack(&fake_cur_stree_stack
, sm
);
219 overwrite_sm_state_stree(&cur_stree
, sm
);
221 if (cond_true_stack
) {
222 overwrite_sm_state_stree_stack(&cond_true_stack
, sm
);
223 overwrite_sm_state_stree_stack(&cond_false_stack
, sm
);
227 struct smatch_state
*get_state(int owner
, const char *name
, struct symbol
*sym
)
229 return get_state_stree(cur_stree
, owner
, name
, sym
);
232 struct smatch_state
*get_state_expr(int owner
, struct expression
*expr
)
236 struct smatch_state
*ret
= NULL
;
238 expr
= strip_expr(expr
);
239 name
= expr_to_var_sym(expr
, &sym
);
242 ret
= get_state(owner
, name
, sym
);
248 struct state_list
*get_possible_states(int owner
, const char *name
, struct symbol
*sym
)
250 struct sm_state
*sms
;
252 sms
= get_sm_state_stree(cur_stree
, owner
, name
, sym
);
254 return sms
->possible
;
258 struct state_list
*get_possible_states_expr(int owner
, struct expression
*expr
)
262 struct state_list
*ret
= NULL
;
264 expr
= strip_expr(expr
);
265 name
= expr_to_var_sym(expr
, &sym
);
268 ret
= get_possible_states(owner
, name
, sym
);
274 struct sm_state
*get_sm_state(int owner
, const char *name
, struct symbol
*sym
)
276 return get_sm_state_stree(cur_stree
, owner
, name
, sym
);
279 struct sm_state
*get_sm_state_expr(int owner
, struct expression
*expr
)
283 struct sm_state
*ret
= NULL
;
285 expr
= strip_expr(expr
);
286 name
= expr_to_var_sym(expr
, &sym
);
289 ret
= get_sm_state(owner
, name
, sym
);
295 void delete_state(int owner
, const char *name
, struct symbol
*sym
)
297 delete_state_stree(&cur_stree
, owner
, name
, sym
);
298 if (cond_true_stack
) {
299 delete_state_stree_stack(&pre_cond_stack
, owner
, name
, sym
);
300 delete_state_stree_stack(&cond_true_stack
, owner
, name
, sym
);
301 delete_state_stree_stack(&cond_false_stack
, owner
, name
, sym
);
305 void delete_state_expr(int owner
, struct expression
*expr
)
310 expr
= strip_expr(expr
);
311 name
= expr_to_var_sym(expr
, &sym
);
314 delete_state(owner
, name
, sym
);
319 struct stree
*get_all_states_from_stree(int owner
, struct stree
*source
)
321 struct stree
*ret
= NULL
;
322 struct sm_state
*tmp
;
324 FOR_EACH_SM(source
, tmp
) {
325 if (tmp
->owner
== owner
)
326 avl_insert(&ret
, tmp
);
327 } END_FOR_EACH_SM(tmp
);
332 struct stree
*get_all_states_stree(int owner
)
334 return get_all_states_from_stree(owner
, cur_stree
);
337 struct stree
*__get_cur_stree(void)
342 int is_reachable(void)
349 void set_true_false_states(int owner
, const char *name
, struct symbol
*sym
,
350 struct smatch_state
*true_state
,
351 struct smatch_state
*false_state
)
354 sm_msg("Smatch Internal Error: cur_stree is read only.");
356 if (option_debug
|| strcmp(check_name(owner
), option_debug_check
) == 0) {
357 struct smatch_state
*tmp
;
359 tmp
= get_state(owner
, name
, sym
);
360 sm_msg("set_true_false '%s'. Was %s. Now T:%s F:%s\n",
361 name
, show_state(tmp
),
362 show_state(true_state
), show_state(false_state
));
368 if (!cond_false_stack
|| !cond_true_stack
) {
369 printf("Error: missing true/false stacks\n");
374 set_state_stree(&cur_stree
, owner
, name
, sym
, true_state
);
375 set_state_stree_stack(&cond_true_stack
, owner
, name
, sym
, true_state
);
378 set_state_stree_stack(&cond_false_stack
, owner
, name
, sym
, false_state
);
381 void set_true_false_states_expr(int owner
, struct expression
*expr
,
382 struct smatch_state
*true_state
,
383 struct smatch_state
*false_state
)
388 expr
= strip_expr(expr
);
389 name
= expr_to_var_sym(expr
, &sym
);
392 set_true_false_states(owner
, name
, sym
, true_state
, false_state
);
397 void __set_true_false_sm(struct sm_state
*true_sm
, struct sm_state
*false_sm
)
402 if (!cond_false_stack
|| !cond_true_stack
) {
403 printf("Error: missing true/false stacks\n");
408 overwrite_sm_state_stree(&cur_stree
, true_sm
);
409 overwrite_sm_state_stree_stack(&cond_true_stack
, true_sm
);
412 overwrite_sm_state_stree_stack(&cond_false_stack
, false_sm
);
415 void nullify_path(void)
417 free_stree(&cur_stree
);
420 void __match_nullify_path_hook(const char *fn
, struct expression
*expr
,
427 * At the start of every function we mark the path
428 * as unnull. That way there is always at least one state
429 * in the cur_stree until nullify_path is called. This
430 * is used in merge_slist() for the first null check.
432 void __unnullify_path(void)
435 set_state(-1, "unnull_path", NULL
, &true_state
);
438 int __path_is_null(void)
445 static void check_stree_stack_free(struct stree_stack
**stack
)
448 sm_msg("smatch internal error: stack not empty");
449 free_stack_and_strees(stack
);
453 void save_all_states(void)
455 __add_ptr_list(&backup
, cur_stree
, 0);
458 __add_ptr_list(&backup
, true_stack
, 0);
460 __add_ptr_list(&backup
, false_stack
, 0);
462 __add_ptr_list(&backup
, pre_cond_stack
, 0);
463 pre_cond_stack
= NULL
;
465 __add_ptr_list(&backup
, cond_true_stack
, 0);
466 cond_true_stack
= NULL
;
467 __add_ptr_list(&backup
, cond_false_stack
, 0);
468 cond_false_stack
= NULL
;
470 __add_ptr_list(&backup
, fake_cur_stree_stack
, 0);
471 fake_cur_stree_stack
= NULL
;
473 __add_ptr_list(&backup
, break_stack
, 0);
475 __add_ptr_list(&backup
, switch_stack
, 0);
477 __add_ptr_list(&backup
, remaining_cases
, 0);
478 remaining_cases
= NULL
;
479 __add_ptr_list(&backup
, default_stack
, 0);
480 default_stack
= NULL
;
481 __add_ptr_list(&backup
, continue_stack
, 0);
482 continue_stack
= NULL
;
484 __add_ptr_list(&backup
, goto_stack
, 0);
488 static void *pop_backup(void)
492 ret
= last_ptr_list(backup
);
493 delete_ptr_list_last(&backup
);
497 void restore_all_states(void)
499 goto_stack
= pop_backup();
501 continue_stack
= pop_backup();
502 default_stack
= pop_backup();
503 remaining_cases
= pop_backup();
504 switch_stack
= pop_backup();
505 break_stack
= pop_backup();
507 fake_cur_stree_stack
= pop_backup();
509 cond_false_stack
= pop_backup();
510 cond_true_stack
= pop_backup();
512 pre_cond_stack
= pop_backup();
513 false_stack
= pop_backup();
514 true_stack
= pop_backup();
516 cur_stree
= pop_backup();
519 void free_goto_stack(void)
521 struct named_stree
*named_stree
;
523 FOR_EACH_PTR(goto_stack
, named_stree
) {
524 free_stree(&named_stree
->stree
);
525 } END_FOR_EACH_PTR(named_stree
);
526 __free_ptr_list((struct ptr_list
**)&goto_stack
);
529 void clear_all_states(void)
532 check_stree_stack_free(&true_stack
);
533 check_stree_stack_free(&false_stack
);
534 check_stree_stack_free(&pre_cond_stack
);
535 check_stree_stack_free(&cond_true_stack
);
536 check_stree_stack_free(&cond_false_stack
);
537 check_stree_stack_free(&break_stack
);
538 check_stree_stack_free(&switch_stack
);
539 check_stree_stack_free(&continue_stack
);
543 free_every_single_sm_state();
546 void __push_cond_stacks(void)
548 push_stree(&cond_true_stack
, NULL
);
549 push_stree(&cond_false_stack
, NULL
);
552 struct stree
*__copy_cond_true_states(void)
556 ret
= pop_stree(&cond_true_stack
);
557 push_stree(&cond_true_stack
, clone_stree(ret
));
561 struct stree
*__copy_cond_false_states(void)
565 ret
= pop_stree(&cond_false_stack
);
566 push_stree(&cond_false_stack
, clone_stree(ret
));
570 struct stree
*__pop_cond_true_stack(void)
572 return pop_stree(&cond_true_stack
);
575 struct stree
*__pop_cond_false_stack(void)
577 return pop_stree(&cond_false_stack
);
581 * This combines the pre cond states with either the true or false states.
583 * a = kmalloc() ; if (a !! foo(a)
584 * In the pre state a is possibly null. In the true state it is non null.
585 * In the false state it is null. Combine the pre and the false to get
586 * that when we call 'foo', 'a' is null.
588 static void __use_cond_stack(struct stree_stack
**stack
)
592 free_stree(&cur_stree
);
594 cur_stree
= pop_stree(&pre_cond_stack
);
595 push_stree(&pre_cond_stack
, clone_stree(cur_stree
));
597 stree
= pop_stree(stack
);
598 overwrite_stree(stree
, &cur_stree
);
599 push_stree(stack
, stree
);
602 void __use_pre_cond_states(void)
604 free_stree(&cur_stree
);
605 cur_stree
= pop_stree(&pre_cond_stack
);
608 void __use_cond_true_states(void)
610 __use_cond_stack(&cond_true_stack
);
613 void __use_cond_false_states(void)
615 __use_cond_stack(&cond_false_stack
);
618 void __negate_cond_stacks(void)
620 struct stree
*old_false
, *old_true
;
622 __use_cond_stack(&cond_false_stack
);
623 old_false
= pop_stree(&cond_false_stack
);
624 old_true
= pop_stree(&cond_true_stack
);
625 push_stree(&cond_false_stack
, old_true
);
626 push_stree(&cond_true_stack
, old_false
);
629 void __and_cond_states(void)
631 and_stree_stack(&cond_true_stack
);
632 or_stree_stack(&pre_cond_stack
, cur_stree
, &cond_false_stack
);
635 void __or_cond_states(void)
637 or_stree_stack(&pre_cond_stack
, cur_stree
, &cond_true_stack
);
638 and_stree_stack(&cond_false_stack
);
641 void __save_pre_cond_states(void)
643 push_stree(&pre_cond_stack
, clone_stree(cur_stree
));
646 void __discard_pre_cond_states(void)
650 tmp
= pop_stree(&pre_cond_stack
);
654 void __use_cond_states(void)
656 struct stree
*pre
, *pre_clone
, *true_states
, *false_states
;
658 pre
= pop_stree(&pre_cond_stack
);
659 pre_clone
= clone_stree(pre
);
661 true_states
= pop_stree(&cond_true_stack
);
662 overwrite_stree(true_states
, &pre
);
663 free_stree(&true_states
);
664 /* we use the true states right away */
665 free_stree(&cur_stree
);
668 false_states
= pop_stree(&cond_false_stack
);
669 overwrite_stree(false_states
, &pre_clone
);
670 free_stree(&false_states
);
671 push_stree(&false_stack
, pre_clone
);
674 void __push_true_states(void)
676 push_stree(&true_stack
, clone_stree(cur_stree
));
679 void __use_false_states(void)
681 free_stree(&cur_stree
);
682 cur_stree
= pop_stree(&false_stack
);
685 void __discard_false_states(void)
689 stree
= pop_stree(&false_stack
);
693 void __merge_false_states(void)
697 stree
= pop_stree(&false_stack
);
698 merge_stree(&cur_stree
, stree
);
702 void __merge_true_states(void)
706 stree
= pop_stree(&true_stack
);
707 merge_stree(&cur_stree
, stree
);
711 void __push_continues(void)
713 push_stree(&continue_stack
, NULL
);
716 void __discard_continues(void)
720 stree
= pop_stree(&continue_stack
);
724 void __process_continues(void)
728 stree
= pop_stree(&continue_stack
);
730 stree
= clone_stree(cur_stree
);
732 merge_stree(&stree
, cur_stree
);
734 push_stree(&continue_stack
, stree
);
737 static int top_stree_empty(struct stree_stack
**stack
)
742 tmp
= pop_stree(stack
);
745 push_stree(stack
, tmp
);
749 /* a silly loop does this: while(i--) { return; } */
750 void __warn_on_silly_pre_loops(void)
752 if (!__path_is_null())
754 if (!top_stree_empty(&continue_stack
))
756 if (!top_stree_empty(&break_stack
))
758 /* if the path was nullified before the loop, then we already
759 printed an error earlier */
760 if (top_stree_empty(&false_stack
))
762 sm_msg("info: loop could be replaced with if statement.");
765 void __merge_continues(void)
769 stree
= pop_stree(&continue_stack
);
770 merge_stree(&cur_stree
, stree
);
774 void __push_breaks(void)
776 push_stree(&break_stack
, NULL
);
779 void __process_breaks(void)
783 stree
= pop_stree(&break_stack
);
785 stree
= clone_stree(cur_stree
);
787 merge_stree(&stree
, cur_stree
);
789 push_stree(&break_stack
, stree
);
792 int __has_breaks(void)
797 stree
= pop_stree(&break_stack
);
799 push_stree(&break_stack
, stree
);
803 void __merge_breaks(void)
807 stree
= pop_stree(&break_stack
);
808 merge_stree(&cur_stree
, stree
);
812 void __use_breaks(void)
814 free_stree(&cur_stree
);
815 cur_stree
= pop_stree(&break_stack
);
818 void __save_switch_states(struct expression
*switch_expr
)
820 push_rl(&remaining_cases
, __get_implied_values(switch_expr
));
821 push_stree(&switch_stack
, clone_stree(cur_stree
));
824 void __merge_switches(struct expression
*switch_expr
, struct expression
*case_expr
)
827 struct stree
*implied_stree
;
829 stree
= pop_stree(&switch_stack
);
830 implied_stree
= __implied_case_stree(switch_expr
, case_expr
, &remaining_cases
, &stree
);
831 merge_stree(&cur_stree
, implied_stree
);
832 free_stree(&implied_stree
);
833 push_stree(&switch_stack
, stree
);
836 void __discard_switches(void)
840 pop_rl(&remaining_cases
);
841 stree
= pop_stree(&switch_stack
);
845 void __push_default(void)
847 push_stree(&default_stack
, NULL
);
850 void __set_default(void)
852 set_state_stree_stack(&default_stack
, 0, "has_default", NULL
, &true_state
);
855 int __pop_default(void)
859 stree
= pop_stree(&default_stack
);
867 static struct named_stree
*alloc_named_stree(const char *name
, struct stree
*stree
)
869 struct named_stree
*named_stree
= __alloc_named_stree(0);
871 named_stree
->name
= (char *)name
;
872 named_stree
->stree
= stree
;
876 void __save_gotos(const char *name
)
878 struct stree
**stree
;
881 stree
= get_named_stree(goto_stack
, name
);
883 merge_stree(stree
, cur_stree
);
886 struct named_stree
*named_stree
;
888 clone
= clone_stree(cur_stree
);
889 named_stree
= alloc_named_stree(name
, clone
);
890 add_ptr_list(&goto_stack
, named_stree
);
894 void __merge_gotos(const char *name
)
896 struct stree
**stree
;
898 stree
= get_named_stree(goto_stack
, name
);
900 merge_stree(&cur_stree
, *stree
);