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
);
81 struct sm_state
*set_state(int owner
, const char *name
, struct symbol
*sym
, struct smatch_state
*state
)
89 sm_msg("Smatch Internal Error: cur_stree is read only.");
91 if (option_debug
|| strcmp(check_name(owner
), option_debug_check
) == 0) {
92 struct smatch_state
*s
;
94 s
= get_state(owner
, name
, sym
);
96 sm_msg("new state. name='%s' [%s] %s",
97 name
, check_name(owner
), show_state(state
));
99 sm_msg("state change name='%s' [%s] %s => %s",
100 name
, check_name(owner
), show_state(s
),
104 if (owner
!= -1 && unreachable())
107 if (fake_cur_stree_stack
)
108 set_state_stree_stack(&fake_cur_stree_stack
, owner
, name
, sym
, state
);
110 ret
= set_state_stree(&cur_stree
, owner
, name
, sym
, state
);
112 if (cond_true_stack
) {
113 set_state_stree_stack(&cond_true_stack
, owner
, name
, sym
, state
);
114 set_state_stree_stack(&cond_false_stack
, owner
, name
, sym
, state
);
119 struct sm_state
*set_state_expr(int owner
, struct expression
*expr
, struct smatch_state
*state
)
123 struct sm_state
*ret
= NULL
;
125 expr
= strip_expr(expr
);
126 name
= expr_to_var_sym(expr
, &sym
);
129 ret
= set_state(owner
, name
, sym
, state
);
135 void __push_fake_cur_stree(void)
137 push_stree(&fake_cur_stree_stack
, NULL
);
138 __save_pre_cond_states();
141 struct stree
*__pop_fake_cur_stree(void)
143 if (!fake_cur_stree_stack
)
144 sm_msg("INTERNAL error: popping too many fake cur strees.");
145 __use_pre_cond_states();
146 return pop_stree(&fake_cur_stree_stack
);
149 void __free_fake_cur_stree(void)
153 __use_pre_cond_states();
154 stree
= pop_stree(&fake_cur_stree_stack
);
158 void __set_fake_cur_stree_fast(struct stree
*stree
)
160 push_stree(&pre_cond_stack
, cur_stree
);
165 void __pop_fake_cur_stree_fast(void)
167 cur_stree
= pop_stree(&pre_cond_stack
);
171 void __merge_stree_into_cur(struct stree
*stree
)
174 struct sm_state
*orig
;
175 struct sm_state
*merged
;
177 FOR_EACH_SM(stree
, sm
) {
178 orig
= get_sm_state(sm
->owner
, sm
->name
, sm
->sym
);
180 merged
= merge_sm_states(orig
, sm
);
184 } END_FOR_EACH_SM(sm
);
187 void __set_sm(struct sm_state
*sm
)
190 sm_msg("Smatch Internal Error: cur_stree is read only.");
193 strcmp(check_name(sm
->owner
), option_debug_check
) == 0) {
194 struct smatch_state
*s
;
196 s
= get_state(sm
->owner
, sm
->name
, sm
->sym
);
198 sm_msg("new state. name='%s' [%s] %s",
199 sm
->name
, check_name(sm
->owner
),
200 show_state(sm
->state
));
202 sm_msg("state change name='%s' [%s] %s => %s",
203 sm
->name
, check_name(sm
->owner
), show_state(s
),
204 show_state(sm
->state
));
210 if (fake_cur_stree_stack
)
211 overwrite_sm_state_stree_stack(&fake_cur_stree_stack
, sm
);
213 overwrite_sm_state_stree(&cur_stree
, sm
);
215 if (cond_true_stack
) {
216 overwrite_sm_state_stree_stack(&cond_true_stack
, sm
);
217 overwrite_sm_state_stree_stack(&cond_false_stack
, sm
);
221 struct smatch_state
*get_state(int owner
, const char *name
, struct symbol
*sym
)
223 return get_state_stree(cur_stree
, owner
, name
, sym
);
226 struct smatch_state
*get_state_expr(int owner
, struct expression
*expr
)
230 struct smatch_state
*ret
= NULL
;
232 expr
= strip_expr(expr
);
233 name
= expr_to_var_sym(expr
, &sym
);
236 ret
= get_state(owner
, name
, sym
);
242 struct state_list
*get_possible_states(int owner
, const char *name
, struct symbol
*sym
)
244 struct sm_state
*sms
;
246 sms
= get_sm_state_stree(cur_stree
, owner
, name
, sym
);
248 return sms
->possible
;
252 struct state_list
*get_possible_states_expr(int owner
, struct expression
*expr
)
256 struct state_list
*ret
= NULL
;
258 expr
= strip_expr(expr
);
259 name
= expr_to_var_sym(expr
, &sym
);
262 ret
= get_possible_states(owner
, name
, sym
);
268 struct sm_state
*get_sm_state(int owner
, const char *name
, struct symbol
*sym
)
270 return get_sm_state_stree(cur_stree
, owner
, name
, sym
);
273 struct sm_state
*get_sm_state_expr(int owner
, struct expression
*expr
)
277 struct sm_state
*ret
= NULL
;
279 expr
= strip_expr(expr
);
280 name
= expr_to_var_sym(expr
, &sym
);
283 ret
= get_sm_state(owner
, name
, sym
);
289 void delete_state(int owner
, const char *name
, struct symbol
*sym
)
291 delete_state_stree(&cur_stree
, owner
, name
, sym
);
292 if (cond_true_stack
) {
293 delete_state_stree_stack(&pre_cond_stack
, owner
, name
, sym
);
294 delete_state_stree_stack(&cond_true_stack
, owner
, name
, sym
);
295 delete_state_stree_stack(&cond_false_stack
, owner
, name
, sym
);
299 void delete_state_expr(int owner
, struct expression
*expr
)
304 expr
= strip_expr(expr
);
305 name
= expr_to_var_sym(expr
, &sym
);
308 delete_state(owner
, name
, sym
);
313 struct stree
*get_all_states_from_stree(int owner
, struct stree
*source
)
315 struct stree
*ret
= NULL
;
316 struct sm_state
*tmp
;
318 FOR_EACH_SM(source
, tmp
) {
319 if (tmp
->owner
== owner
)
320 avl_insert(&ret
, tmp
);
321 } END_FOR_EACH_SM(tmp
);
326 struct stree
*get_all_states_stree(int owner
)
328 return get_all_states_from_stree(owner
, cur_stree
);
331 struct stree
*__get_cur_stree(void)
336 int is_reachable(void)
343 void set_true_false_states(int owner
, const char *name
, struct symbol
*sym
,
344 struct smatch_state
*true_state
,
345 struct smatch_state
*false_state
)
348 sm_msg("Smatch Internal Error: cur_stree is read only.");
350 if (option_debug
|| strcmp(check_name(owner
), option_debug_check
) == 0) {
351 struct smatch_state
*tmp
;
353 tmp
= get_state(owner
, name
, sym
);
354 sm_msg("set_true_false '%s'. Was %s. Now T:%s F:%s\n",
355 name
, show_state(tmp
),
356 show_state(true_state
), show_state(false_state
));
362 if (!cond_false_stack
|| !cond_true_stack
) {
363 printf("Error: missing true/false stacks\n");
368 set_state_stree(&cur_stree
, owner
, name
, sym
, true_state
);
369 set_state_stree_stack(&cond_true_stack
, owner
, name
, sym
, true_state
);
372 set_state_stree_stack(&cond_false_stack
, owner
, name
, sym
, false_state
);
375 void set_true_false_states_expr(int owner
, struct expression
*expr
,
376 struct smatch_state
*true_state
,
377 struct smatch_state
*false_state
)
382 expr
= strip_expr(expr
);
383 name
= expr_to_var_sym(expr
, &sym
);
386 set_true_false_states(owner
, name
, sym
, true_state
, false_state
);
391 void __set_true_false_sm(struct sm_state
*true_sm
, struct sm_state
*false_sm
)
396 if (!cond_false_stack
|| !cond_true_stack
) {
397 printf("Error: missing true/false stacks\n");
402 overwrite_sm_state_stree(&cur_stree
, true_sm
);
403 overwrite_sm_state_stree_stack(&cond_true_stack
, true_sm
);
406 overwrite_sm_state_stree_stack(&cond_false_stack
, false_sm
);
409 void nullify_path(void)
411 free_stree(&cur_stree
);
414 void __match_nullify_path_hook(const char *fn
, struct expression
*expr
,
421 * At the start of every function we mark the path
422 * as unnull. That way there is always at least one state
423 * in the cur_stree until nullify_path is called. This
424 * is used in merge_slist() for the first null check.
426 void __unnullify_path(void)
429 set_state(-1, "unnull_path", NULL
, &true_state
);
432 int __path_is_null(void)
439 static void check_stree_stack_free(struct stree_stack
**stack
)
442 sm_msg("smatch internal error: stack not empty");
443 free_stack_and_strees(stack
);
447 void save_all_states(void)
449 __add_ptr_list(&backup
, cur_stree
, 0);
452 __add_ptr_list(&backup
, true_stack
, 0);
454 __add_ptr_list(&backup
, false_stack
, 0);
456 __add_ptr_list(&backup
, pre_cond_stack
, 0);
457 pre_cond_stack
= NULL
;
459 __add_ptr_list(&backup
, cond_true_stack
, 0);
460 cond_true_stack
= NULL
;
461 __add_ptr_list(&backup
, cond_false_stack
, 0);
462 cond_false_stack
= NULL
;
464 __add_ptr_list(&backup
, fake_cur_stree_stack
, 0);
465 fake_cur_stree_stack
= NULL
;
467 __add_ptr_list(&backup
, break_stack
, 0);
469 __add_ptr_list(&backup
, switch_stack
, 0);
471 __add_ptr_list(&backup
, remaining_cases
, 0);
472 remaining_cases
= NULL
;
473 __add_ptr_list(&backup
, default_stack
, 0);
474 default_stack
= NULL
;
475 __add_ptr_list(&backup
, continue_stack
, 0);
476 continue_stack
= NULL
;
478 __add_ptr_list(&backup
, goto_stack
, 0);
482 static void *pop_backup(void)
486 ret
= last_ptr_list(backup
);
487 delete_ptr_list_last(&backup
);
491 void restore_all_states(void)
493 goto_stack
= pop_backup();
495 continue_stack
= pop_backup();
496 default_stack
= pop_backup();
497 remaining_cases
= pop_backup();
498 switch_stack
= pop_backup();
499 break_stack
= pop_backup();
501 fake_cur_stree_stack
= pop_backup();
503 cond_false_stack
= pop_backup();
504 cond_true_stack
= pop_backup();
506 pre_cond_stack
= pop_backup();
507 false_stack
= pop_backup();
508 true_stack
= pop_backup();
510 cur_stree
= pop_backup();
513 void free_goto_stack(void)
515 struct named_stree
*named_stree
;
517 FOR_EACH_PTR(goto_stack
, named_stree
) {
518 free_stree(&named_stree
->stree
);
519 } END_FOR_EACH_PTR(named_stree
);
520 __free_ptr_list((struct ptr_list
**)&goto_stack
);
523 void clear_all_states(void)
526 check_stree_stack_free(&true_stack
);
527 check_stree_stack_free(&false_stack
);
528 check_stree_stack_free(&pre_cond_stack
);
529 check_stree_stack_free(&cond_true_stack
);
530 check_stree_stack_free(&cond_false_stack
);
531 check_stree_stack_free(&break_stack
);
532 check_stree_stack_free(&switch_stack
);
533 check_stree_stack_free(&continue_stack
);
537 free_every_single_sm_state();
540 void __push_cond_stacks(void)
542 push_stree(&cond_true_stack
, NULL
);
543 push_stree(&cond_false_stack
, NULL
);
546 struct stree
*__copy_cond_true_states(void)
550 ret
= pop_stree(&cond_true_stack
);
551 push_stree(&cond_true_stack
, clone_stree(ret
));
555 struct stree
*__copy_cond_false_states(void)
559 ret
= pop_stree(&cond_false_stack
);
560 push_stree(&cond_false_stack
, clone_stree(ret
));
564 struct stree
*__pop_cond_true_stack(void)
566 return pop_stree(&cond_true_stack
);
569 struct stree
*__pop_cond_false_stack(void)
571 return pop_stree(&cond_false_stack
);
575 * This combines the pre cond states with either the true or false states.
577 * a = kmalloc() ; if (a !! foo(a)
578 * In the pre state a is possibly null. In the true state it is non null.
579 * In the false state it is null. Combine the pre and the false to get
580 * that when we call 'foo', 'a' is null.
582 static void __use_cond_stack(struct stree_stack
**stack
)
586 free_stree(&cur_stree
);
588 cur_stree
= pop_stree(&pre_cond_stack
);
589 push_stree(&pre_cond_stack
, clone_stree(cur_stree
));
591 stree
= pop_stree(stack
);
592 overwrite_stree(stree
, &cur_stree
);
593 push_stree(stack
, stree
);
596 void __use_pre_cond_states(void)
598 free_stree(&cur_stree
);
599 cur_stree
= pop_stree(&pre_cond_stack
);
602 void __use_cond_true_states(void)
604 __use_cond_stack(&cond_true_stack
);
607 void __use_cond_false_states(void)
609 __use_cond_stack(&cond_false_stack
);
612 void __negate_cond_stacks(void)
614 struct stree
*old_false
, *old_true
;
616 __use_cond_stack(&cond_false_stack
);
617 old_false
= pop_stree(&cond_false_stack
);
618 old_true
= pop_stree(&cond_true_stack
);
619 push_stree(&cond_false_stack
, old_true
);
620 push_stree(&cond_true_stack
, old_false
);
623 void __and_cond_states(void)
625 and_stree_stack(&cond_true_stack
);
626 or_stree_stack(&pre_cond_stack
, cur_stree
, &cond_false_stack
);
629 void __or_cond_states(void)
631 or_stree_stack(&pre_cond_stack
, cur_stree
, &cond_true_stack
);
632 and_stree_stack(&cond_false_stack
);
635 void __save_pre_cond_states(void)
637 push_stree(&pre_cond_stack
, clone_stree(cur_stree
));
640 void __discard_pre_cond_states(void)
644 tmp
= pop_stree(&pre_cond_stack
);
648 void __use_cond_states(void)
650 struct stree
*pre
, *pre_clone
, *true_states
, *false_states
;
652 pre
= pop_stree(&pre_cond_stack
);
653 pre_clone
= clone_stree(pre
);
655 true_states
= pop_stree(&cond_true_stack
);
656 overwrite_stree(true_states
, &pre
);
657 free_stree(&true_states
);
658 /* we use the true states right away */
659 free_stree(&cur_stree
);
662 false_states
= pop_stree(&cond_false_stack
);
663 overwrite_stree(false_states
, &pre_clone
);
664 free_stree(&false_states
);
665 push_stree(&false_stack
, pre_clone
);
668 void __push_true_states(void)
670 push_stree(&true_stack
, clone_stree(cur_stree
));
673 void __use_false_states(void)
675 free_stree(&cur_stree
);
676 cur_stree
= pop_stree(&false_stack
);
679 void __discard_false_states(void)
683 stree
= pop_stree(&false_stack
);
687 void __merge_false_states(void)
691 stree
= pop_stree(&false_stack
);
692 merge_stree(&cur_stree
, stree
);
696 void __merge_true_states(void)
700 stree
= pop_stree(&true_stack
);
701 merge_stree(&cur_stree
, stree
);
705 void __push_continues(void)
707 push_stree(&continue_stack
, NULL
);
710 void __discard_continues(void)
714 stree
= pop_stree(&continue_stack
);
718 void __process_continues(void)
722 stree
= pop_stree(&continue_stack
);
724 stree
= clone_stree(cur_stree
);
726 merge_stree(&stree
, cur_stree
);
728 push_stree(&continue_stack
, stree
);
731 static int top_stree_empty(struct stree_stack
**stack
)
736 tmp
= pop_stree(stack
);
739 push_stree(stack
, tmp
);
743 /* a silly loop does this: while(i--) { return; } */
744 void __warn_on_silly_pre_loops(void)
746 if (!__path_is_null())
748 if (!top_stree_empty(&continue_stack
))
750 if (!top_stree_empty(&break_stack
))
752 /* if the path was nullified before the loop, then we already
753 printed an error earlier */
754 if (top_stree_empty(&false_stack
))
756 sm_msg("info: loop could be replaced with if statement.");
759 void __merge_continues(void)
763 stree
= pop_stree(&continue_stack
);
764 merge_stree(&cur_stree
, stree
);
768 void __push_breaks(void)
770 push_stree(&break_stack
, NULL
);
773 void __process_breaks(void)
777 stree
= pop_stree(&break_stack
);
779 stree
= clone_stree(cur_stree
);
781 merge_stree(&stree
, cur_stree
);
783 push_stree(&break_stack
, stree
);
786 int __has_breaks(void)
791 stree
= pop_stree(&break_stack
);
793 push_stree(&break_stack
, stree
);
797 void __merge_breaks(void)
801 stree
= pop_stree(&break_stack
);
802 merge_stree(&cur_stree
, stree
);
806 void __use_breaks(void)
808 free_stree(&cur_stree
);
809 cur_stree
= pop_stree(&break_stack
);
812 void __save_switch_states(struct expression
*switch_expr
)
814 push_rl(&remaining_cases
, __get_implied_values(switch_expr
));
815 push_stree(&switch_stack
, clone_stree(cur_stree
));
818 void __merge_switches(struct expression
*switch_expr
, struct expression
*case_expr
)
821 struct stree
*implied_stree
;
823 stree
= pop_stree(&switch_stack
);
824 implied_stree
= __implied_case_stree(switch_expr
, case_expr
, &remaining_cases
, &stree
);
825 merge_stree(&cur_stree
, implied_stree
);
826 free_stree(&implied_stree
);
827 push_stree(&switch_stack
, stree
);
830 void __discard_switches(void)
834 pop_rl(&remaining_cases
);
835 stree
= pop_stree(&switch_stack
);
839 void __push_default(void)
841 push_stree(&default_stack
, NULL
);
844 void __set_default(void)
846 set_state_stree_stack(&default_stack
, 0, "has_default", NULL
, &true_state
);
849 int __pop_default(void)
853 stree
= pop_stree(&default_stack
);
861 static struct named_stree
*alloc_named_stree(const char *name
, struct stree
*stree
)
863 struct named_stree
*named_stree
= __alloc_named_stree(0);
865 named_stree
->name
= (char *)name
;
866 named_stree
->stree
= stree
;
870 void __save_gotos(const char *name
)
872 struct stree
**stree
;
875 stree
= get_named_stree(goto_stack
, name
);
877 merge_stree(stree
, cur_stree
);
880 struct named_stree
*named_stree
;
882 clone
= clone_stree(cur_stree
);
883 named_stree
= alloc_named_stree(name
, clone
);
884 add_ptr_list(&goto_stack
, named_stree
);
888 void __merge_gotos(const char *name
)
890 struct stree
**stree
;
892 stree
= get_named_stree(goto_stack
, name
);
894 merge_stree(&cur_stree
, *stree
);