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 merged
= { .name
= "merged" };
42 struct smatch_state true_state
= { .name
= "true" };
43 struct smatch_state false_state
= { .name
= "false" };
45 static struct stree
*cur_stree
; /* current states */
47 static struct stree_stack
*true_stack
; /* states after a t/f branch */
48 static struct stree_stack
*false_stack
;
49 static struct stree_stack
*pre_cond_stack
; /* states before a t/f branch */
51 static struct stree_stack
*cond_true_stack
; /* states affected by a branch */
52 static struct stree_stack
*cond_false_stack
;
54 static struct stree_stack
*fake_cur_stree_stack
;
57 static struct stree_stack
*break_stack
;
58 static struct stree_stack
*switch_stack
;
59 static struct range_list_stack
*remaining_cases
;
60 static struct stree_stack
*default_stack
;
61 static struct stree_stack
*continue_stack
;
63 static struct named_stree_stack
*goto_stack
;
65 static struct ptr_list
*backup
;
69 void __print_cur_stree(void)
71 __print_stree(cur_stree
);
74 static int in_declarations_bit(void)
76 struct statement
*tmp
;
78 FOR_EACH_PTR_REVERSE(big_statement_stack
, tmp
) {
79 if (tmp
->type
== STMT_DECLARATION
)
82 } END_FOR_EACH_PTR_REVERSE(tmp
);
88 static int reset_warnings
= 1;
96 if (in_declarations_bit())
99 /* option spammy turns on a noisier version of this */
100 if (reset_warnings
&& !option_spammy
)
101 sm_msg("info: ignoring unreachable code.");
107 struct sm_state
*set_state(int owner
, const char *name
, struct symbol
*sym
, struct smatch_state
*state
)
109 struct sm_state
*ret
;
115 sm_msg("Smatch Internal Error: cur_stree is read only.");
117 if (option_debug
|| strcmp(check_name(owner
), option_debug_check
) == 0) {
118 struct smatch_state
*s
;
120 s
= get_state(owner
, name
, sym
);
122 printf("%d new state. name='%s' [%s] %s\n",
123 get_lineno(), name
, check_name(owner
), show_state(state
));
125 printf("%d state change name='%s' [%s] %s => %s\n",
126 get_lineno(), name
, check_name(owner
), show_state(s
),
130 if (owner
!= -1 && unreachable())
133 if (fake_cur_stree_stack
)
134 set_state_stree_stack(&fake_cur_stree_stack
, owner
, name
, sym
, state
);
136 ret
= set_state_stree(&cur_stree
, owner
, name
, sym
, state
);
138 if (cond_true_stack
) {
139 set_state_stree_stack(&cond_true_stack
, owner
, name
, sym
, state
);
140 set_state_stree_stack(&cond_false_stack
, owner
, name
, sym
, state
);
145 struct sm_state
*set_state_expr(int owner
, struct expression
*expr
, struct smatch_state
*state
)
149 struct sm_state
*ret
= NULL
;
151 expr
= strip_expr(expr
);
152 name
= expr_to_var_sym(expr
, &sym
);
155 ret
= set_state(owner
, name
, sym
, state
);
161 void __push_fake_cur_stree()
163 push_stree(&fake_cur_stree_stack
, NULL
);
164 __save_pre_cond_states();
167 struct stree
*__pop_fake_cur_stree()
169 __use_pre_cond_states();
170 return pop_stree(&fake_cur_stree_stack
);
173 void __free_fake_cur_stree()
177 __use_pre_cond_states();
178 stree
= pop_stree(&fake_cur_stree_stack
);
182 void __set_fake_cur_stree_fast(struct stree
*stree
)
184 push_stree(&pre_cond_stack
, cur_stree
);
189 void __pop_fake_cur_stree_fast()
191 cur_stree
= pop_stree(&pre_cond_stack
);
195 void __merge_stree_into_cur(struct stree
*stree
)
198 struct sm_state
*orig
;
199 struct sm_state
*merged
;
201 FOR_EACH_SM(stree
, sm
) {
202 orig
= get_sm_state(sm
->owner
, sm
->name
, sm
->sym
);
204 merged
= merge_sm_states(orig
, sm
);
208 } END_FOR_EACH_SM(sm
);
211 void __set_sm(struct sm_state
*sm
)
214 sm_msg("Smatch Internal Error: cur_stree is read only.");
217 strcmp(check_name(sm
->owner
), option_debug_check
) == 0) {
218 struct smatch_state
*s
;
220 s
= get_state(sm
->owner
, sm
->name
, sm
->sym
);
222 printf("%d new state. name='%s' [%s] %s\n",
223 get_lineno(), sm
->name
, check_name(sm
->owner
),
224 show_state(sm
->state
));
226 printf("%d state change name='%s' [%s] %s => %s\n",
227 get_lineno(), sm
->name
, check_name(sm
->owner
), show_state(s
),
228 show_state(sm
->state
));
234 if (fake_cur_stree_stack
)
235 overwrite_sm_state_stree_stack(&fake_cur_stree_stack
, sm
);
237 overwrite_sm_state_stree(&cur_stree
, sm
);
239 if (cond_true_stack
) {
240 overwrite_sm_state_stree_stack(&cond_true_stack
, sm
);
241 overwrite_sm_state_stree_stack(&cond_false_stack
, sm
);
245 struct smatch_state
*get_state(int owner
, const char *name
, struct symbol
*sym
)
247 return get_state_stree(cur_stree
, owner
, name
, sym
);
250 struct smatch_state
*get_state_expr(int owner
, struct expression
*expr
)
254 struct smatch_state
*ret
= NULL
;
256 expr
= strip_expr(expr
);
257 name
= expr_to_var_sym(expr
, &sym
);
260 ret
= get_state(owner
, name
, sym
);
266 struct state_list
*get_possible_states(int owner
, const char *name
, struct symbol
*sym
)
268 struct sm_state
*sms
;
270 sms
= get_sm_state_stree(cur_stree
, owner
, name
, sym
);
272 return sms
->possible
;
276 struct state_list
*get_possible_states_expr(int owner
, struct expression
*expr
)
280 struct state_list
*ret
= NULL
;
282 expr
= strip_expr(expr
);
283 name
= expr_to_var_sym(expr
, &sym
);
286 ret
= get_possible_states(owner
, name
, sym
);
292 struct sm_state
*get_sm_state(int owner
, const char *name
, struct symbol
*sym
)
294 return get_sm_state_stree(cur_stree
, owner
, name
, sym
);
297 struct sm_state
*get_sm_state_expr(int owner
, struct expression
*expr
)
301 struct sm_state
*ret
= NULL
;
303 expr
= strip_expr(expr
);
304 name
= expr_to_var_sym(expr
, &sym
);
307 ret
= get_sm_state(owner
, name
, sym
);
313 void delete_state(int owner
, const char *name
, struct symbol
*sym
)
315 delete_state_stree(&cur_stree
, owner
, name
, sym
);
316 if (cond_true_stack
) {
317 delete_state_stree_stack(&pre_cond_stack
, owner
, name
, sym
);
318 delete_state_stree_stack(&cond_true_stack
, owner
, name
, sym
);
319 delete_state_stree_stack(&cond_false_stack
, owner
, name
, sym
);
323 void delete_state_expr(int owner
, struct expression
*expr
)
328 expr
= strip_expr(expr
);
329 name
= expr_to_var_sym(expr
, &sym
);
332 delete_state(owner
, name
, sym
);
337 struct stree
*get_all_states_from_stree(int owner
, struct stree
*source
)
339 struct stree
*ret
= NULL
;
340 struct sm_state
*tmp
;
342 FOR_EACH_SM(source
, tmp
) {
343 if (tmp
->owner
== owner
)
344 avl_insert(&ret
, tmp
);
345 } END_FOR_EACH_SM(tmp
);
350 struct stree
*get_all_states_stree(int owner
)
352 return get_all_states_from_stree(owner
, cur_stree
);
355 struct stree
*__get_cur_stree(void)
360 int is_reachable(void)
367 void set_true_false_states(int owner
, const char *name
, struct symbol
*sym
,
368 struct smatch_state
*true_state
,
369 struct smatch_state
*false_state
)
371 if (option_debug
|| strcmp(check_name(owner
), option_debug_check
) == 0) {
372 struct smatch_state
*tmp
;
374 tmp
= get_state(owner
, name
, sym
);
375 printf("%d set_true_false '%s'. Was %s. Now T:%s F:%s\n",
376 get_lineno(), name
, show_state(tmp
),
377 show_state(true_state
), show_state(false_state
));
383 if (!cond_false_stack
|| !cond_true_stack
) {
384 printf("Error: missing true/false stacks\n");
389 set_state_stree(&cur_stree
, owner
, name
, sym
, true_state
);
390 set_state_stree_stack(&cond_true_stack
, owner
, name
, sym
, true_state
);
393 set_state_stree_stack(&cond_false_stack
, owner
, name
, sym
, false_state
);
396 void set_true_false_states_expr(int owner
, struct expression
*expr
,
397 struct smatch_state
*true_state
,
398 struct smatch_state
*false_state
)
403 expr
= strip_expr(expr
);
404 name
= expr_to_var_sym(expr
, &sym
);
407 set_true_false_states(owner
, name
, sym
, true_state
, false_state
);
412 void __set_true_false_sm(struct sm_state
*true_sm
, struct sm_state
*false_sm
)
417 if (!cond_false_stack
|| !cond_true_stack
) {
418 printf("Error: missing true/false stacks\n");
423 overwrite_sm_state_stree(&cur_stree
, true_sm
);
424 overwrite_sm_state_stree_stack(&cond_true_stack
, true_sm
);
427 overwrite_sm_state_stree_stack(&cond_false_stack
, false_sm
);
430 void nullify_path(void)
432 free_stree(&cur_stree
);
435 void __match_nullify_path_hook(const char *fn
, struct expression
*expr
,
442 * At the start of every function we mark the path
443 * as unnull. That way there is always at least one state
444 * in the cur_stree until nullify_path is called. This
445 * is used in merge_slist() for the first null check.
447 void __unnullify_path(void)
449 set_state(-1, "unnull_path", NULL
, &true_state
);
452 int __path_is_null(void)
459 static void check_stree_stack_free(struct stree_stack
**stack
)
462 sm_msg("smatch internal error: stack not empty");
463 free_stack_and_strees(stack
);
467 void save_all_states(void)
469 __add_ptr_list(&backup
, cur_stree
, 0);
472 __add_ptr_list(&backup
, true_stack
, 0);
474 __add_ptr_list(&backup
, false_stack
, 0);
476 __add_ptr_list(&backup
, pre_cond_stack
, 0);
477 pre_cond_stack
= NULL
;
479 __add_ptr_list(&backup
, cond_true_stack
, 0);
480 cond_true_stack
= NULL
;
481 __add_ptr_list(&backup
, cond_false_stack
, 0);
482 cond_false_stack
= NULL
;
484 __add_ptr_list(&backup
, fake_cur_stree_stack
, 0);
485 fake_cur_stree_stack
= NULL
;
487 __add_ptr_list(&backup
, break_stack
, 0);
489 __add_ptr_list(&backup
, switch_stack
, 0);
491 __add_ptr_list(&backup
, remaining_cases
, 0);
492 remaining_cases
= NULL
;
493 __add_ptr_list(&backup
, default_stack
, 0);
494 default_stack
= NULL
;
495 __add_ptr_list(&backup
, continue_stack
, 0);
496 continue_stack
= NULL
;
498 __add_ptr_list(&backup
, goto_stack
, 0);
502 static void *pop_backup(void)
506 ret
= last_ptr_list(backup
);
507 delete_ptr_list_last(&backup
);
511 void restore_all_states(void)
513 goto_stack
= pop_backup();
515 continue_stack
= pop_backup();
516 default_stack
= pop_backup();
517 remaining_cases
= pop_backup();
518 switch_stack
= pop_backup();
519 break_stack
= pop_backup();
521 fake_cur_stree_stack
= pop_backup();
523 cond_false_stack
= pop_backup();
524 cond_true_stack
= pop_backup();
526 pre_cond_stack
= pop_backup();
527 false_stack
= pop_backup();
528 true_stack
= pop_backup();
530 cur_stree
= pop_backup();
533 void free_goto_stack(void)
535 struct named_stree
*named_stree
;
537 FOR_EACH_PTR(goto_stack
, named_stree
) {
538 free_stree(&named_stree
->stree
);
539 } END_FOR_EACH_PTR(named_stree
);
540 __free_ptr_list((struct ptr_list
**)&goto_stack
);
543 void clear_all_states(void)
546 check_stree_stack_free(&true_stack
);
547 check_stree_stack_free(&false_stack
);
548 check_stree_stack_free(&pre_cond_stack
);
549 check_stree_stack_free(&cond_true_stack
);
550 check_stree_stack_free(&cond_false_stack
);
551 check_stree_stack_free(&break_stack
);
552 check_stree_stack_free(&switch_stack
);
553 check_stree_stack_free(&continue_stack
);
557 free_every_single_sm_state();
560 void __push_cond_stacks(void)
562 push_stree(&cond_true_stack
, NULL
);
563 push_stree(&cond_false_stack
, NULL
);
566 struct stree
*__copy_cond_true_states(void)
570 ret
= pop_stree(&cond_true_stack
);
571 push_stree(&cond_true_stack
, clone_stree(ret
));
575 struct stree
*__copy_cond_false_states(void)
579 ret
= pop_stree(&cond_false_stack
);
580 push_stree(&cond_false_stack
, clone_stree(ret
));
584 struct stree
*__pop_cond_true_stack(void)
586 return pop_stree(&cond_true_stack
);
589 struct stree
*__pop_cond_false_stack(void)
591 return pop_stree(&cond_false_stack
);
595 * This combines the pre cond states with either the true or false states.
597 * a = kmalloc() ; if (a !! foo(a)
598 * In the pre state a is possibly null. In the true state it is non null.
599 * In the false state it is null. Combine the pre and the false to get
600 * that when we call 'foo', 'a' is null.
602 static void __use_cond_stack(struct stree_stack
**stack
)
606 free_stree(&cur_stree
);
608 cur_stree
= pop_stree(&pre_cond_stack
);
609 push_stree(&pre_cond_stack
, clone_stree(cur_stree
));
611 stree
= pop_stree(stack
);
612 overwrite_stree(stree
, &cur_stree
);
613 push_stree(stack
, stree
);
616 void __use_pre_cond_states(void)
618 free_stree(&cur_stree
);
619 cur_stree
= pop_stree(&pre_cond_stack
);
622 void __use_cond_true_states(void)
624 __use_cond_stack(&cond_true_stack
);
627 void __use_cond_false_states(void)
629 __use_cond_stack(&cond_false_stack
);
632 void __negate_cond_stacks(void)
634 struct stree
*old_false
, *old_true
;
636 __use_cond_stack(&cond_false_stack
);
637 old_false
= pop_stree(&cond_false_stack
);
638 old_true
= pop_stree(&cond_true_stack
);
639 push_stree(&cond_false_stack
, old_true
);
640 push_stree(&cond_true_stack
, old_false
);
643 void __and_cond_states(void)
645 and_stree_stack(&cond_true_stack
);
646 or_stree_stack(&pre_cond_stack
, cur_stree
, &cond_false_stack
);
649 void __or_cond_states(void)
651 or_stree_stack(&pre_cond_stack
, cur_stree
, &cond_true_stack
);
652 and_stree_stack(&cond_false_stack
);
655 void __save_pre_cond_states(void)
657 push_stree(&pre_cond_stack
, clone_stree(cur_stree
));
660 void __discard_pre_cond_states(void)
664 tmp
= pop_stree(&pre_cond_stack
);
668 void __use_cond_states(void)
670 struct stree
*pre
, *pre_clone
, *true_states
, *false_states
;
672 pre
= pop_stree(&pre_cond_stack
);
673 pre_clone
= clone_stree(pre
);
675 true_states
= pop_stree(&cond_true_stack
);
676 overwrite_stree(true_states
, &pre
);
677 free_stree(&true_states
);
678 /* we use the true states right away */
679 free_stree(&cur_stree
);
682 false_states
= pop_stree(&cond_false_stack
);
683 overwrite_stree(false_states
, &pre_clone
);
684 free_stree(&false_states
);
685 push_stree(&false_stack
, pre_clone
);
688 void __push_true_states(void)
690 push_stree(&true_stack
, clone_stree(cur_stree
));
693 void __use_false_states(void)
695 free_stree(&cur_stree
);
696 cur_stree
= pop_stree(&false_stack
);
699 void __discard_false_states(void)
703 stree
= pop_stree(&false_stack
);
707 void __merge_false_states(void)
711 stree
= pop_stree(&false_stack
);
712 merge_stree(&cur_stree
, stree
);
716 void __merge_true_states(void)
720 stree
= pop_stree(&true_stack
);
721 merge_stree(&cur_stree
, stree
);
725 void __push_continues(void)
727 push_stree(&continue_stack
, NULL
);
730 void __discard_continues(void)
734 stree
= pop_stree(&continue_stack
);
738 void __process_continues(void)
742 stree
= pop_stree(&continue_stack
);
744 stree
= clone_stree(cur_stree
);
746 merge_stree(&stree
, cur_stree
);
748 push_stree(&continue_stack
, stree
);
751 static int top_stree_empty(struct stree_stack
**stack
)
756 tmp
= pop_stree(stack
);
759 push_stree(stack
, tmp
);
763 /* a silly loop does this: while(i--) { return; } */
764 void __warn_on_silly_pre_loops(void)
766 if (!__path_is_null())
768 if (!top_stree_empty(&continue_stack
))
770 if (!top_stree_empty(&break_stack
))
772 /* if the path was nullified before the loop, then we already
773 printed an error earlier */
774 if (top_stree_empty(&false_stack
))
776 sm_msg("info: loop could be replaced with if statement.");
779 void __merge_continues(void)
783 stree
= pop_stree(&continue_stack
);
784 merge_stree(&cur_stree
, stree
);
788 void __push_breaks(void)
790 push_stree(&break_stack
, NULL
);
793 void __process_breaks(void)
797 stree
= pop_stree(&break_stack
);
799 stree
= clone_stree(cur_stree
);
801 merge_stree(&stree
, cur_stree
);
803 push_stree(&break_stack
, stree
);
806 int __has_breaks(void)
811 stree
= pop_stree(&break_stack
);
813 push_stree(&break_stack
, stree
);
817 void __merge_breaks(void)
821 stree
= pop_stree(&break_stack
);
822 merge_stree(&cur_stree
, stree
);
826 void __use_breaks(void)
828 free_stree(&cur_stree
);
829 cur_stree
= pop_stree(&break_stack
);
832 void __save_switch_states(struct expression
*switch_expr
)
834 push_rl(&remaining_cases
, __get_implied_values(switch_expr
));
835 push_stree(&switch_stack
, clone_stree(cur_stree
));
838 void __merge_switches(struct expression
*switch_expr
, struct expression
*case_expr
)
841 struct stree
*implied_stree
;
843 stree
= pop_stree(&switch_stack
);
844 implied_stree
= __implied_case_stree(switch_expr
, case_expr
, &remaining_cases
, &stree
);
845 merge_stree(&cur_stree
, implied_stree
);
846 free_stree(&implied_stree
);
847 push_stree(&switch_stack
, stree
);
850 void __discard_switches(void)
854 pop_rl(&remaining_cases
);
855 stree
= pop_stree(&switch_stack
);
859 void __push_default(void)
861 push_stree(&default_stack
, NULL
);
864 void __set_default(void)
866 set_state_stree_stack(&default_stack
, 0, "has_default", NULL
, &true_state
);
869 int __pop_default(void)
873 stree
= pop_stree(&default_stack
);
881 static struct named_stree
*alloc_named_stree(const char *name
, struct stree
*stree
)
883 struct named_stree
*named_stree
= __alloc_named_stree(0);
885 named_stree
->name
= (char *)name
;
886 named_stree
->stree
= stree
;
890 void __save_gotos(const char *name
)
892 struct stree
**stree
;
895 stree
= get_named_stree(goto_stack
, name
);
897 merge_stree(stree
, cur_stree
);
900 struct named_stree
*named_stree
;
902 clone
= clone_stree(cur_stree
);
903 named_stree
= alloc_named_stree(name
, clone
);
904 add_ptr_list(&goto_stack
, named_stree
);
908 void __merge_gotos(const char *name
)
910 struct stree
**stree
;
912 stree
= get_named_stree(goto_stack
, name
);
914 merge_stree(&cur_stree
, *stree
);