?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
helper: fix expr_to_str() for function calls
[smatch.git] / smatch_extra.c
blobd55a83d9e71e0ac8c61599653be67f45d88d0439
1 /*
2 * sparse/smatch_extra.c
3 *
4 * Copyright (C) 2008 Dan Carpenter.
5 *
6 * Licensed under the Open Software License version 1.1
7 *
8 */
9
10 /*
11 * smatch_extra.c is supposed to track the value of every variable.
12 *
13 */
14
15 #include <stdlib.h>
16 #include <errno.h>
17 #ifndef __USE_ISOC99
18 #define __USE_ISOC99
19 #endif
20 #include <limits.h>
21 #include "parse.h"
22 #include "smatch.h"
23 #include "smatch_slist.h"
24 #include "smatch_extra.h"
25
26 static int my_id;
27
28 struct string_list *__ignored_macros = NULL;
29 static int in_warn_on_macro()
30 {
31 struct statement *stmt;
32 char *tmp;
33 char *macro;
34
35 stmt = get_current_statement();
36 macro = get_macro_name(stmt->pos);
37 if (!macro)
38 return 0;
39
40 FOR_EACH_PTR(__ignored_macros, tmp) {
41 if (!strcmp(tmp, macro))
42 return 1;
43 } END_FOR_EACH_PTR(tmp);
44 return 0;
45 }
46
47 typedef void (mod_hook)(const char *name, struct symbol *sym, struct smatch_state *state);
48 DECLARE_PTR_LIST(void_fn_list, mod_hook *);
49 static struct void_fn_list *extra_mod_hooks;
50 void add_extra_mod_hook(mod_hook *fn)
51 {
52 mod_hook **p = malloc(sizeof(mod_hook *));
53 *p = fn;
54 add_ptr_list(&extra_mod_hooks, p);
55 }
56
57 void call_extra_mod_hooks(const char *name, struct symbol *sym, struct smatch_state *state)
58 {
59 mod_hook **fn;
60
61 FOR_EACH_PTR(extra_mod_hooks, fn) {
62 (*fn)(name, sym, state);
63 } END_FOR_EACH_PTR(fn);
64 }
65
66 struct sm_state *set_extra_mod(const char *name, struct symbol *sym, struct smatch_state *state)
67 {
68 if (in_warn_on_macro())
69 return NULL;
70 remove_from_equiv(name, sym);
71 call_extra_mod_hooks(name, sym, state);
72 return set_state(SMATCH_EXTRA, name, sym, state);
73 }
74
75 struct sm_state *set_extra_expr_mod(struct expression *expr, struct smatch_state *state)
76 {
77 struct symbol *sym;
78 char *name;
79 struct sm_state *ret = NULL;
80
81 expr = strip_expr(expr);
82 name = expr_to_var_sym(expr, &sym);
83 if (!name || !sym)
84 goto free;
85 ret = set_extra_mod(name, sym, state);
86 free:
87 free_string(name);
88 return ret;
89 }
90
91 void set_extra_nomod(const char *name, struct symbol *sym, struct smatch_state *state)
92 {
93 struct relation *rel;
94 struct smatch_state *orig_state;
95
96 orig_state = get_state(SMATCH_EXTRA, name, sym);
97
98 if (!estate_related(orig_state)) {
99 set_state(SMATCH_EXTRA, name, sym, state);
100 return;
101 }
102
103 set_related(state, estate_related(orig_state));
104 FOR_EACH_PTR(estate_related(orig_state), rel) {
105 if (option_debug_related)
106 sm_msg("updating related %s to %s", rel->name, state->name);
107 set_state(SMATCH_EXTRA, rel->name, rel->sym, state);
108 } END_FOR_EACH_PTR(rel);
109 }
110
111 /*
112 * This is for return_implies_state() hooks which modify a SMATCH_EXTRA state
113 */
114 void set_extra_expr_nomod(struct expression *expr, struct smatch_state *state)
115 {
116 char *name;
117 struct symbol *sym;
118
119 name = expr_to_var_sym(expr, &sym);
120 if (!name || !sym)
121 goto free;
122 set_extra_nomod(name, sym, state);
123 free:
124 free_string(name);
125
126 }
127
128 static void set_extra_true_false(const char *name, struct symbol *sym,
129 struct smatch_state *true_state,
130 struct smatch_state *false_state)
131 {
132 struct relation *rel;
133 struct smatch_state *orig_state;
134
135 if (in_warn_on_macro())
136 return;
137
138 orig_state = get_state(SMATCH_EXTRA, name, sym);
139
140 if (!estate_related(orig_state)) {
141 set_true_false_states(SMATCH_EXTRA, name, sym, true_state, false_state);
142 return;
143 }
144
145 if (true_state)
146 set_related(true_state, estate_related(orig_state));
147 if (false_state)
148 set_related(false_state, estate_related(orig_state));
149
150 FOR_EACH_PTR(estate_related(orig_state), rel) {
151 set_true_false_states(SMATCH_EXTRA, rel->name, rel->sym,
152 true_state, false_state);
153 } END_FOR_EACH_PTR(rel);
154 }
155
156 static void set_extra_expr_true_false(struct expression *expr,
157 struct smatch_state *true_state,
158 struct smatch_state *false_state)
159 {
160 char *name;
161 struct symbol *sym;
162
163 expr = strip_expr(expr);
164 name = expr_to_var_sym(expr, &sym);
165 if (!name || !sym)
166 goto free;
167 set_extra_true_false(name, sym, true_state, false_state);
168 free:
169 free_string(name);
170 }
171
172 static struct sm_state *handle_canonical_while_count_down(struct statement *loop)
173 {
174 struct expression *iter_var;
175 struct expression *condition;
176 struct sm_state *sm;
177 struct smatch_state *estate;
178 sval_t start;
179
180 condition = strip_expr(loop->iterator_pre_condition);
181 if (!condition)
182 return NULL;
183 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
184 return NULL;
185 if (condition->op != SPECIAL_DECREMENT)
186 return NULL;
187
188 iter_var = condition->unop;
189 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
190 if (!sm)
191 return NULL;
192 if (sval_cmp_val(estate_min(sm->state), 0) < 0)
193 return NULL;
194 start = estate_max(sm->state);
195 if (sval_cmp_val(start, 0) <= 0)
196 return NULL;
197 if (!sval_is_max(start))
198 start.value--;
199
200 if (condition->type == EXPR_PREOP) {
201 estate = alloc_estate_range(sval_type_val(start.type, 1), start);
202 if (estate_has_hard_max(sm->state))
203 estate_set_hard_max(estate);
204 set_extra_expr_mod(iter_var, estate);
205 }
206 if (condition->type == EXPR_POSTOP) {
207 estate = alloc_estate_range(sval_type_val(start.type, 0), start);
208 if (estate_has_hard_max(sm->state))
209 estate_set_hard_max(estate);
210 set_extra_expr_mod(iter_var, estate);
211 }
212 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
213 }
214
215 static struct sm_state *handle_canonical_for_inc(struct expression *iter_expr,
216 struct expression *condition)
217 {
218 struct expression *iter_var;
219 struct sm_state *sm;
220 struct smatch_state *estate;
221 sval_t start, end, dummy;
222
223 iter_var = iter_expr->unop;
224 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
225 if (!sm)
226 return NULL;
227 if (!estate_get_single_value(sm->state, &start))
228 return NULL;
229 if (get_implied_max(condition->right, &end))
230 end = sval_cast(get_type(iter_var), end);
231 else
232 end = sval_type_max(get_type(iter_var));
233
234 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
235 return NULL;
236
237 switch (condition->op) {
238 case SPECIAL_NOTEQUAL:
239 case '<':
240 if (!sval_is_min(end))
241 end.value--;
242 break;
243 case SPECIAL_LTE:
244 break;
245 default:
246 return NULL;
247 }
248 if (sval_cmp(end, start) < 0)
249 return NULL;
250 estate = alloc_estate_range(start, end);
251 if (get_hard_max(condition->right, &dummy))
252 estate_set_hard_max(estate);
253 set_extra_expr_mod(iter_var, estate);
254 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
255 }
256
257 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
258 struct expression *condition)
259 {
260 struct expression *iter_var;
261 struct sm_state *sm;
262 struct smatch_state *estate;
263 sval_t start, end;
264
265 iter_var = iter_expr->unop;
266 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
267 if (!sm)
268 return NULL;
269 if (!estate_get_single_value(sm->state, &start))
270 return NULL;
271 if (!get_implied_min(condition->right, &end))
272 end = sval_type_min(get_type(iter_var));
273 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
274 return NULL;
275
276 switch (condition->op) {
277 case SPECIAL_NOTEQUAL:
278 case '>':
279 if (!sval_is_min(end) && !sval_is_max(end))
280 end.value++;
281 break;
282 case SPECIAL_GTE:
283 break;
284 default:
285 return NULL;
286 }
287 if (sval_cmp(end, start) > 0)
288 return NULL;
289 estate = alloc_estate_range(end, start);
290 estate_set_hard_max(estate);
291 set_extra_expr_mod(iter_var, estate);
292 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
293 }
294
295 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
296 {
297 struct expression *iter_expr;
298 struct expression *condition;
299
300 if (!loop->iterator_post_statement)
301 return NULL;
302 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
303 return NULL;
304 iter_expr = loop->iterator_post_statement->expression;
305 if (!loop->iterator_pre_condition)
306 return NULL;
307 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
308 return NULL;
309 condition = loop->iterator_pre_condition;
310
311 if (iter_expr->op == SPECIAL_INCREMENT)
312 return handle_canonical_for_inc(iter_expr, condition);
313 if (iter_expr->op == SPECIAL_DECREMENT)
314 return handle_canonical_for_dec(iter_expr, condition);
315 return NULL;
316 }
317
318 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
319 {
320 struct sm_state *ret;
321
322 __push_fake_cur_slist();
323 if (!loop->iterator_post_statement)
324 ret = handle_canonical_while_count_down(loop);
325 else
326 ret = handle_canonical_for_loops(loop);
327 *slist = __pop_fake_cur_slist();
328 return ret;
329 }
330
331 int __iterator_unchanged(struct sm_state *sm)
332 {
333 if (!sm)
334 return 0;
335 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
336 return 1;
337 return 0;
338 }
339
340 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
341 {
342 sval_t after_value;
343
344 /* paranoid checking. prolly not needed */
345 condition = strip_expr(condition);
346 if (!condition)
347 return;
348 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
349 return;
350 if (condition->op != SPECIAL_DECREMENT)
351 return;
352 after_value = estate_min(sm->state);
353 after_value.value--;
354 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
355 }
356
357 void __extra_pre_loop_hook_after(struct sm_state *sm,
358 struct statement *iterator,
359 struct expression *condition)
360 {
361 struct expression *iter_expr;
362 sval_t limit;
363 struct smatch_state *state;
364
365 if (!iterator) {
366 while_count_down_after(sm, condition);
367 return;
368 }
369
370 iter_expr = iterator->expression;
371
372 if (condition->type != EXPR_COMPARE)
373 return;
374 if (iter_expr->op == SPECIAL_INCREMENT) {
375 limit = sval_binop(estate_max(sm->state), '+',
376 sval_type_val(estate_type(sm->state), 1));
377 } else {
378 limit = sval_binop(estate_min(sm->state), '-',
379 sval_type_val(estate_type(sm->state), 1));
380 }
381 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
382 if (iter_expr->op == SPECIAL_INCREMENT)
383 state = alloc_estate_range(estate_min(sm->state), limit);
384 else
385 state = alloc_estate_range(limit, estate_max(sm->state));
386 } else {
387 state = alloc_estate_sval(limit);
388 }
389 if (!estate_has_hard_max(sm->state))
390 estate_clear_hard_max(state);
391 set_extra_mod(sm->name, sm->sym, state);
392 }
393
394 static struct state_list *unmatched_slist;
395 static struct smatch_state *unmatched_state(struct sm_state *sm)
396 {
397 struct smatch_state *state;
398
399 if (unmatched_slist) {
400 state = get_state_slist(unmatched_slist, SMATCH_EXTRA, sm->name, sm->sym);
401 if (state)
402 return state;
403 }
404 return alloc_estate_whole(estate_type(sm->state));
405 }
406
407 static void clear_the_pointed_at(struct expression *expr, struct state_list *slist)
408 {
409 char *name;
410 struct symbol *sym;
411 struct sm_state *tmp;
412
413 name = expr_to_var_sym(expr, &sym);
414 if (!name || !sym)
415 goto free;
416
417 FOR_EACH_PTR(slist, tmp) {
418 if (tmp->name[0] != '*')
419 continue;
420 if (tmp->sym != sym)
421 continue;
422 if (strcmp(tmp->name + 1, name) != 0)
423 continue;
424 set_extra_mod(tmp->name, tmp->sym, alloc_estate_whole(estate_type(tmp->state)));
425 } END_FOR_EACH_PTR(tmp);
426
427 free:
428 free_string(name);
429 }
430
431 static void match_function_call(struct expression *expr)
432 {
433 struct expression *arg;
434 struct expression *tmp;
435 struct state_list *slist;
436
437 slist = get_all_states(SMATCH_EXTRA);
438
439 FOR_EACH_PTR(expr->args, arg) {
440 tmp = strip_expr(arg);
441 if (tmp->type == EXPR_PREOP && tmp->op == '&')
442 set_extra_expr_mod(tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
443 else
444 clear_the_pointed_at(tmp, slist);
445 } END_FOR_EACH_PTR(arg);
446
447 free_slist(&slist);
448 }
449
450 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
451 {
452 if (!one || !two)
453 return 0;
454 if (one->type == SYM_PTR && two->type == SYM_PTR)
455 return 1;
456 return types_equiv(one, two);
457 }
458
459 static void match_vanilla_assign(struct expression *left, struct expression *right)
460 {
461 struct range_list *rl = NULL;
462 struct symbol *right_sym;
463 struct symbol *left_type;
464 struct symbol *right_type;
465 char *right_name = NULL;
466 struct symbol *sym;
467 char *name;
468 sval_t tmp;
469 struct smatch_state *state;
470
471 name = expr_to_var_sym(left, &sym);
472 if (!name)
473 return;
474
475 left_type = get_type(left);
476 right_type = get_type(right);
477
478 right_name = expr_to_var_sym(right, &right_sym);
479 if (right_name && right_sym &&
480 types_equiv_or_pointer(left_type, right_type)) {
481 set_equiv(left, right);
482 goto free;
483 }
484
485 if (get_implied_rl(right, &rl)) {
486 rl = cast_rl(left_type, rl);
487 state = alloc_estate_rl(rl);
488 if (get_hard_max(right, &tmp))
489 estate_set_hard_max(state);
490 } else {
491 rl = alloc_whole_rl(right_type);
492 rl = cast_rl(left_type, rl);
493 state = alloc_estate_rl(rl);
494 }
495 set_extra_mod(name, sym, state);
496 free:
497 free_string(right_name);
498 }
499
500 static int op_remove_assign(int op)
501 {
502 switch (op) {
503 case SPECIAL_ADD_ASSIGN:
504 return '+';
505 case SPECIAL_SUB_ASSIGN:
506 return '-';
507 case SPECIAL_MUL_ASSIGN:
508 return '*';
509 case SPECIAL_DIV_ASSIGN:
510 return '/';
511 case SPECIAL_MOD_ASSIGN:
512 return '%';
513 case SPECIAL_AND_ASSIGN:
514 return '&';
515 case SPECIAL_OR_ASSIGN:
516 return '|';
517 case SPECIAL_XOR_ASSIGN:
518 return '^';
519 case SPECIAL_SHL_ASSIGN:
520 return SPECIAL_LEFTSHIFT;
521 case SPECIAL_SHR_ASSIGN:
522 return SPECIAL_RIGHTSHIFT;
523 default:
524 return op;
525 }
526 }
527
528 static void match_assign(struct expression *expr)
529 {
530 struct range_list *rl = NULL;
531 struct expression *left;
532 struct expression *right;
533 struct expression *binop_expr;
534 struct symbol *left_type;
535 struct symbol *right_type;
536 struct symbol *sym;
537 char *name;
538 sval_t value;
539 int known;
540 sval_t right_min, right_max;
541 sval_t tmp;
542
543 left = strip_expr(expr->left);
544
545 right = strip_expr(expr->right);
546 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
547 right = strip_expr(right->left);
548
549 if (is_condition(expr->right))
550 return; /* handled in smatch_condition.c */
551 if (expr->op == '=' && right->type == EXPR_CALL)
552 return; /* handled in smatch_function_hooks.c */
553 if (expr->op == '=') {
554 match_vanilla_assign(left, right);
555 return;
556 }
557
558 name = expr_to_var_sym(left, &sym);
559 if (!name)
560 return;
561
562 left_type = get_type(left);
563 right_type = get_type(right);
564
565 right_min = sval_type_min(right_type);
566 right_max = sval_type_max(right_type);
567
568 known = get_implied_value(right, &value);
569 switch (expr->op) {
570 case SPECIAL_ADD_ASSIGN:
571 if (get_implied_min(left, &tmp)) {
572 if (known)
573 right_min = sval_binop(tmp, '+', value);
574 else
575 right_min = tmp;
576 }
577 if (!inside_loop() && known && get_implied_max(left, &tmp))
578 right_max = sval_binop(tmp, '+', value);
579 break;
580 case SPECIAL_SUB_ASSIGN:
581 if (get_implied_max(left, &tmp)) {
582 if (known)
583 right_max = sval_binop(tmp, '-', value);
584 else
585 right_max = tmp;
586 }
587 if (!inside_loop() && known && get_implied_min(left, &tmp))
588 right_min = sval_binop(tmp, '-', value);
589 break;
590 case SPECIAL_AND_ASSIGN:
591 case SPECIAL_MOD_ASSIGN:
592 binop_expr = binop_expression(expr->left,
593 op_remove_assign(expr->op),
594 expr->right);
595 if (get_implied_rl(binop_expr, &rl)) {
596 rl = cast_rl(left_type, rl);
597 set_extra_mod(name, sym, alloc_estate_rl(rl));
598 goto free;
599 }
600 }
601 if (!sval_is_min(right_min) || !sval_is_max(right_max))
602 rl = cast_rl(left_type, alloc_rl(right_min, right_max));
603 else
604 rl = alloc_whole_rl(left_type);
605 set_extra_mod(name, sym, alloc_estate_rl(rl));
606 free:
607 free_string(name);
608 }
609
610 static void reset_struct_members(struct sm_state *sm)
611 {
612 if (!estate_rl(sm->state))
613 return;
614 set_extra_mod(sm->name, sm->sym, alloc_estate_whole(estate_type(sm->state)));
615 }
616
617 static struct smatch_state *increment_state(struct smatch_state *state)
618 {
619 sval_t min = estate_min(state);
620 sval_t max = estate_max(state);
621
622 if (!estate_rl(state))
623 return NULL;
624
625 if (inside_loop())
626 max = sval_type_max(max.type);
627
628 if (!sval_is_min(min) && !sval_is_max(min))
629 min.value++;
630 if (!sval_is_min(max) && !sval_is_max(max))
631 max.value++;
632 return alloc_estate_range(min, max);
633 }
634
635 static struct smatch_state *decrement_state(struct smatch_state *state)
636 {
637 sval_t min = estate_min(state);
638 sval_t max = estate_max(state);
639
640 if (!estate_rl(state))
641 return NULL;
642
643 if (inside_loop())
644 min = sval_type_min(min.type);
645
646 if (!sval_is_min(min) && !sval_is_max(min))
647 min.value--;
648 if (!sval_is_min(max) && !sval_is_max(max))
649 max.value--;
650 return alloc_estate_range(min, max);
651 }
652
653 static void unop_expr(struct expression *expr)
654 {
655 struct smatch_state *state;
656
657 if (expr->smatch_flags & Handled)
658 return;
659
660 switch (expr->op) {
661 case SPECIAL_INCREMENT:
662 state = get_state_expr(SMATCH_EXTRA, expr->unop);
663 state = increment_state(state);
664 if (!state)
665 state = alloc_estate_whole(get_type(expr));
666 set_extra_expr_mod(expr->unop, state);
667 break;
668 case SPECIAL_DECREMENT:
669 state = get_state_expr(SMATCH_EXTRA, expr->unop);
670 state = decrement_state(state);
671 if (!state)
672 state = alloc_estate_whole(get_type(expr));
673 set_extra_expr_mod(expr->unop, state);
674 break;
675 default:
676 return;
677 }
678 }
679
680 static void asm_expr(struct statement *stmt)
681 {
682
683 struct expression *expr;
684 struct symbol *type;
685 int state = 0;
686
687 FOR_EACH_PTR(stmt->asm_outputs, expr) {
688 switch (state) {
689 case 0: /* identifier */
690 case 1: /* constraint */
691 state++;
692 continue;
693 case 2: /* expression */
694 state = 0;
695 type = get_type(strip_expr(expr));
696 set_extra_expr_mod(expr, alloc_estate_whole(type));
697 continue;
698 }
699 } END_FOR_EACH_PTR(expr);
700 }
701
702 static void delete_state_tracker(struct tracker *t)
703 {
704 remove_from_equiv(t->name, t->sym);
705 delete_state(t->owner, t->name, t->sym);
706 }
707
708 static void scoped_state_extra(const char *name, struct symbol *sym)
709 {
710 struct tracker *t;
711
712 t = alloc_tracker(SMATCH_EXTRA, name, sym);
713 add_scope_hook((scope_hook *)&delete_state_tracker, t);
714 }
715
716 static void match_declarations(struct symbol *sym)
717 {
718 const char *name;
719
720 if (sym->ident) {
721 name = sym->ident->name;
722 if (!sym->initializer) {
723 set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
724 scoped_state_extra(name, sym);
725 }
726 }
727 }
728
729 static void check_dereference(struct expression *expr)
730 {
731 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
732 }
733
734 static void match_dereferences(struct expression *expr)
735 {
736 if (expr->type != EXPR_PREOP)
737 return;
738 check_dereference(expr->unop);
739 }
740
741 static void match_pointer_as_array(struct expression *expr)
742 {
743 if (!is_array(expr))
744 return;
745 check_dereference(expr->unop->left);
746 }
747
748 static void set_param_dereferenced(struct expression *arg, char *unused)
749 {
750 check_dereference(arg);
751 }
752
753 static void match_function_def(struct symbol *sym)
754 {
755 struct symbol *arg;
756
757 FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
758 if (!arg->ident)
759 continue;
760 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
761 } END_FOR_EACH_PTR(arg);
762 }
763
764 static int match_func_comparison(struct expression *expr)
765 {
766 struct expression *left = strip_expr(expr->left);
767 struct expression *right = strip_expr(expr->right);
768 sval_t sval;
769
770 if (left->type == EXPR_CALL) {
771 if (!get_implied_value(right, &sval))
772 return 1;
773 function_comparison(expr->op, left, sval, 1);
774 return 1;
775 }
776
777 if (right->type == EXPR_CALL) {
778 if (!get_implied_value(left, &sval))
779 return 1;
780 function_comparison(expr->op, right, sval, 0);
781 return 1;
782 }
783
784 return 0;
785 }
786
787 static sval_t add_one(sval_t sval)
788 {
789 sval.value++;
790 return sval;
791 }
792
793 static sval_t sub_one(sval_t sval)
794 {
795 sval.value--;
796 return sval;
797 }
798
799 static void match_comparison(struct expression *expr)
800 {
801 struct expression *left = strip_expr(expr->left);
802 struct expression *right = strip_expr(expr->right);
803 struct symbol *type;
804 struct range_list *left_orig;
805 struct range_list *left_true;
806 struct range_list *left_false;
807 struct range_list *right_orig;
808 struct range_list *right_true;
809 struct range_list *right_false;
810 struct smatch_state *left_true_state;
811 struct smatch_state *left_false_state;
812 struct smatch_state *right_true_state;
813 struct smatch_state *right_false_state;
814 sval_t min, max, dummy;
815 int left_postop = 0;
816 int right_postop = 0;
817
818 if (match_func_comparison(expr))
819 return;
820
821 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
822 if (left->type == EXPR_POSTOP) {
823 left->smatch_flags |= Handled;
824 left_postop = left->op;
825 }
826 left = strip_expr(left->unop);
827 }
828 while (left->type == EXPR_ASSIGNMENT)
829 left = strip_expr(left->left);
830
831 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
832 if (right->type == EXPR_POSTOP) {
833 right->smatch_flags |= Handled;
834 right_postop = right->op;
835 }
836 right = strip_expr(right->unop);
837 }
838
839 type = get_type(expr);
840 if (!type)
841 type = &llong_ctype;
842
843 if (get_implied_rl(left, &left_orig)) {
844 left_orig = cast_rl(type, left_orig);
845 } else {
846 min = sval_type_min(get_type(left));
847 max = sval_type_max(get_type(left));
848 left_orig = cast_rl(type, alloc_rl(min, max));
849 }
850
851 if (get_implied_rl(right, &right_orig)) {
852 right_orig = cast_rl(type, right_orig);
853 } else {
854 min = sval_type_min(get_type(right));
855 max = sval_type_max(get_type(right));
856 right_orig = cast_rl(type, alloc_rl(min, max));
857 }
858 min = sval_type_min(type);
859 max = sval_type_max(type);
860
861 left_true = clone_rl(left_orig);
862 left_false = clone_rl(left_orig);
863 right_true = clone_rl(right_orig);
864 right_false = clone_rl(right_orig);
865
866 switch (expr->op) {
867 case '<':
868 case SPECIAL_UNSIGNED_LT:
869 left_true = remove_range(left_orig, rl_max(right_orig), max);
870 if (!sval_is_min(rl_min(right_orig))) {
871 left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
872 }
873
874 right_true = remove_range(right_orig, min, rl_min(left_orig));
875 if (!sval_is_max(rl_max(left_orig)))
876 right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
877 break;
878 case SPECIAL_UNSIGNED_LTE:
879 case SPECIAL_LTE:
880 if (!sval_is_max(rl_max(right_orig)))
881 left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
882 left_false = remove_range(left_orig, min, rl_min(right_orig));
883
884 if (!sval_is_min(rl_min(left_orig)))
885 right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
886 right_false = remove_range(right_orig, rl_max(left_orig), max);
887
888 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
889 left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
890 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
891 right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
892 break;
893 case SPECIAL_EQUAL:
894 if (!sval_is_max(rl_max(right_orig))) {
895 left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
896 }
897 if (!sval_is_min(rl_min(right_orig))) {
898 left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
899 }
900 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
901 left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
902
903 if (!sval_is_max(rl_max(left_orig)))
904 right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
905 if (!sval_is_min(rl_min(left_orig)))
906 right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
907 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
908 right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
909 break;
910 case SPECIAL_UNSIGNED_GTE:
911 case SPECIAL_GTE:
912 if (!sval_is_min(rl_min(right_orig)))
913 left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
914 left_false = remove_range(left_orig, rl_max(right_orig), max);
915
916 if (!sval_is_max(rl_max(left_orig)))
917 right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
918 right_false = remove_range(right_orig, min, rl_min(left_orig));
919
920 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
921 right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
922 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
923 left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
924 break;
925 case '>':
926 case SPECIAL_UNSIGNED_GT:
927 left_true = remove_range(left_orig, min, rl_min(right_orig));
928 if (!sval_is_max(rl_max(right_orig)))
929 left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
930
931 right_true = remove_range(right_orig, rl_max(left_orig), max);
932 if (!sval_is_min(rl_min(left_orig)))
933 right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
934 break;
935 case SPECIAL_NOTEQUAL:
936 if (!sval_is_max(rl_max(right_orig)))
937 left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
938 if (!sval_is_min(rl_min(right_orig)))
939 left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
940 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
941 left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
942
943 if (!sval_is_max(rl_max(left_orig)))
944 right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
945 if (!sval_is_min(rl_min(left_orig)))
946 right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
947 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
948 right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
949 break;
950 default:
951 return;
952 }
953
954 left_true = rl_truncate_cast(get_type(left), left_true);
955 left_false = rl_truncate_cast(get_type(left), left_false);
956 right_true = rl_truncate_cast(get_type(right), right_true);
957 right_false = rl_truncate_cast(get_type(right), right_false);
958
959 left_true_state = alloc_estate_rl(left_true);
960 left_false_state = alloc_estate_rl(left_false);
961 right_true_state = alloc_estate_rl(right_true);
962 right_false_state = alloc_estate_rl(right_false);
963
964 switch (expr->op) {
965 case '<':
966 case SPECIAL_UNSIGNED_LT:
967 case SPECIAL_UNSIGNED_LTE:
968 case SPECIAL_LTE:
969 if (get_hard_max(right, &dummy))
970 estate_set_hard_max(left_true_state);
971 if (get_hard_max(left, &dummy))
972 estate_set_hard_max(right_false_state);
973 break;
974 case '>':
975 case SPECIAL_UNSIGNED_GT:
976 case SPECIAL_UNSIGNED_GTE:
977 case SPECIAL_GTE:
978 if (get_hard_max(left, &dummy))
979 estate_set_hard_max(right_true_state);
980 if (get_hard_max(right, &dummy))
981 estate_set_hard_max(left_false_state);
982 break;
983 }
984
985 if (get_hard_max(left, &dummy)) {
986 estate_set_hard_max(left_true_state);
987 estate_set_hard_max(left_false_state);
988 }
989 if (get_hard_max(right, &dummy)) {
990 estate_set_hard_max(right_true_state);
991 estate_set_hard_max(right_false_state);
992 }
993
994 if (left_postop == SPECIAL_INCREMENT) {
995 left_true_state = increment_state(left_true_state);
996 left_false_state = increment_state(left_false_state);
997 }
998 if (left_postop == SPECIAL_DECREMENT) {
999 left_true_state = decrement_state(left_true_state);
1000 left_false_state = decrement_state(left_false_state);
1001 }
1002 if (right_postop == SPECIAL_INCREMENT) {
1003 right_true_state = increment_state(right_true_state);
1004 right_false_state = increment_state(right_false_state);
1005 }
1006 if (right_postop == SPECIAL_DECREMENT) {
1007 right_true_state = decrement_state(right_true_state);
1008 right_false_state = decrement_state(right_false_state);
1009 }
1010
1011 set_extra_expr_true_false(left, left_true_state, left_false_state);
1012 set_extra_expr_true_false(right, right_true_state, right_false_state);
1013 }
1014
1015 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
1016 void __extra_match_condition(struct expression *expr)
1017 {
1018 struct symbol *sym;
1019 char *name;
1020 struct smatch_state *pre_state;
1021 struct smatch_state *true_state;
1022 struct smatch_state *false_state;
1023
1024 expr = strip_expr(expr);
1025 switch (expr->type) {
1026 case EXPR_CALL:
1027 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
1028 return;
1029 case EXPR_PREOP:
1030 case EXPR_SYMBOL:
1031 case EXPR_DEREF: {
1032 sval_t zero;
1033
1034 zero = sval_blank(expr);
1035 zero.value = 0;
1036
1037 name = expr_to_var_sym(expr, &sym);
1038 if (!name)
1039 return;
1040 pre_state = get_state(my_id, name, sym);
1041 true_state = estate_filter_sval(pre_state, zero);
1042 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
1043 false_state = alloc_estate_sval(zero);
1044 else
1045 false_state = alloc_estate_empty();
1046 set_extra_true_false(name, sym, true_state, false_state);
1047 free_string(name);
1048 return;
1049 }
1050 case EXPR_COMPARE:
1051 match_comparison(expr);
1052 return;
1053 case EXPR_ASSIGNMENT:
1054 __extra_match_condition(expr->left);
1055 return;
1056 }
1057 }
1058
1059 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
1060 int implied_not_equal(struct expression *expr, long long val)
1061 {
1062 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
1063 }
1064
1065 static void struct_member_callback(struct expression *call, int param, char *printed_name, struct smatch_state *state)
1066 {
1067 if (estate_is_whole(state))
1068 return;
1069 sql_insert_caller_info(call, PARAM_VALUE, param, printed_name, state->name);
1070 }
1071
1072 static void db_limited_before(void)
1073 {
1074 unmatched_slist = clone_slist(__get_cur_slist());
1075 }
1076
1077 static void db_limited_after(void)
1078 {
1079 free_slist(&unmatched_slist);
1080 }
1081
1082 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value)
1083 {
1084 struct expression *arg;
1085 char *name;
1086 struct symbol *sym;
1087 struct sm_state *sm;
1088 struct symbol *type;
1089 struct range_list *rl;
1090 struct range_list *limit;
1091 struct range_list *new;
1092
1093 while (expr->type == EXPR_ASSIGNMENT)
1094 expr = strip_expr(expr->right);
1095 if (expr->type != EXPR_CALL)
1096 return;
1097
1098 arg = get_argument_from_call_expr(expr->args, param);
1099 if (!arg)
1100 return;
1101
1102 name = get_variable_from_key(arg, key, &sym);
1103 if (!name || !sym)
1104 goto free;
1105
1106 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1107 type = get_member_type_from_key(arg, key);
1108 if (sm)
1109 rl = estate_rl(sm->state);
1110 else
1111 rl = alloc_whole_rl(type);
1112
1113 str_to_rl(type, value, &limit);
1114 new = rl_intersection(rl, limit);
1115
1116 /* We want to preserve the implications here */
1117 if (sm && rl_equiv(estate_rl(sm->state), new))
1118 __set_sm(sm);
1119 else
1120 set_extra_nomod(name, sym, alloc_estate_rl(new));
1121
1122 free:
1123 free_string(name);
1124 }
1125
1126 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1127 {
1128 struct expression *arg;
1129 char *name;
1130 struct symbol *sym;
1131 struct symbol *type;
1132 struct smatch_state *state;
1133 struct range_list *added = NULL;
1134 struct range_list *new;
1135
1136 while (expr->type == EXPR_ASSIGNMENT)
1137 expr = strip_expr(expr->right);
1138 if (expr->type != EXPR_CALL)
1139 return;
1140
1141 arg = get_argument_from_call_expr(expr->args, param);
1142 if (!arg)
1143 return;
1144 name = get_variable_from_key(arg, key, &sym);
1145 if (!name || !sym)
1146 goto free;
1147
1148 type = get_member_type_from_key(arg, key);
1149 state = get_state(SMATCH_EXTRA, name, sym);
1150 if (state) {
1151 str_to_rl(type, value, &added);
1152 new = rl_union(estate_rl(state), added);
1153 } else {
1154 new = alloc_whole_rl(type);
1155 }
1156
1157 set_extra_mod(name, sym, alloc_estate_rl(new));
1158 free:
1159 free_string(name);
1160 }
1161
1162 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
1163 {
1164 struct expression *arg;
1165 struct symbol *type;
1166 struct range_list *rl;
1167 char member_name[256];
1168 char *name;
1169 struct symbol *sym;
1170
1171 while (expr->type == EXPR_ASSIGNMENT)
1172 expr = strip_expr(expr->right);
1173 if (expr->type != EXPR_CALL)
1174 return;
1175 arg = get_argument_from_call_expr(expr->args, param);
1176 arg = strip_expr(arg);
1177 if (!arg)
1178 return;
1179
1180 if (strcmp(key, "*$$") == 0) {
1181 struct symbol *sym;
1182 char buf[256];
1183 char *name;
1184
1185 if (arg->type == EXPR_PREOP && arg->op == '&') {
1186 arg = strip_expr(arg->unop);
1187 name = expr_to_var_sym(arg, &sym);
1188 } else {
1189 char *tmp = expr_to_var_sym(arg, &sym);
1190
1191 if (!tmp)
1192 return;
1193 snprintf(buf, sizeof(buf), "*%s", tmp);
1194 name = alloc_string(buf);
1195 free_string(tmp);
1196 }
1197 if (!name || !sym) {
1198 free_string(name);
1199 return;
1200 }
1201 type = get_type(arg);
1202 str_to_rl(type, value, &rl);
1203 set_extra_mod(name, sym, alloc_estate_rl(rl));
1204 free_string(name);
1205 return;
1206 }
1207
1208 if (arg->type == EXPR_PREOP && arg->op == '&') {
1209 arg = strip_expr(arg->unop);
1210 name = expr_to_var_sym(arg, &sym);
1211 if (!name || !sym)
1212 goto free;
1213 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
1214 } else {
1215 name = expr_to_var_sym(arg, &sym);
1216 if (!name || !sym)
1217 goto free;
1218 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1219 }
1220 type = get_member_type_from_key(arg, key);
1221 if (!type)
1222 goto free;
1223 str_to_rl(type, value, &rl);
1224 set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1225 free:
1226 free_string(name);
1227 }
1228
1229 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1230 {
1231 struct symbol *type;
1232 struct symbol *sym;
1233 char *name;
1234 char member_name[256];
1235 struct range_list *rl;
1236
1237 if (expr->type != EXPR_ASSIGNMENT)
1238 return;
1239
1240 name = expr_to_var_sym(expr->left, &sym);
1241 if (!name || !sym)
1242 goto free;
1243 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1244 type = get_member_type_from_key(expr->left, key);
1245 if (!type)
1246 return;
1247 str_to_rl(type, value, &rl);
1248 set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1249
1250 free:
1251 free_string(name);
1252 }
1253
1254 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1255 {
1256 if (estate_is_whole(state))
1257 return;
1258
1259 sql_insert_return_states(return_id, return_ranges, RETURN_VALUE, -1,
1260 printed_name, state->name);
1261 }
1262
1263 static void match_call_info(struct expression *expr)
1264 {
1265 struct range_list *rl = NULL;
1266 struct expression *arg;
1267 struct symbol *type;
1268 int i = 0;
1269
1270 FOR_EACH_PTR(expr->args, arg) {
1271 type = get_arg_type(expr->fn, i);
1272
1273 if (get_implied_rl(arg, &rl))
1274 rl = cast_rl(type, rl);
1275 else
1276 rl = cast_rl(type, alloc_whole_rl(get_type(arg)));
1277
1278 sql_insert_caller_info(expr, PARAM_VALUE, i, "$$", show_rl(rl));
1279 i++;
1280 } END_FOR_EACH_PTR(arg);
1281 }
1282
1283 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1284 {
1285 struct range_list *rl = NULL;
1286 struct smatch_state *state;
1287 struct symbol *type;
1288 char fullname[256];
1289
1290 if (strcmp(key, "*$$") == 0)
1291 snprintf(fullname, sizeof(fullname), "*%s", name);
1292 else if (strncmp(key, "$$", 2) == 0)
1293 snprintf(fullname, 256, "%s%s", name, key + 2);
1294 else
1295 return;
1296
1297 type = get_member_type_from_key(symbol_expression(sym), key);
1298 str_to_rl(type, value, &rl);
1299 state = alloc_estate_rl(rl);
1300 set_state(SMATCH_EXTRA, fullname, sym, state);
1301 }
1302
1303 void register_smatch_extra(int id)
1304 {
1305 my_id = id;
1306
1307 add_merge_hook(my_id, &merge_estates);
1308 add_unmatched_state_hook(my_id, &unmatched_state);
1309 add_hook(&match_function_def, FUNC_DEF_HOOK);
1310 add_hook(&match_declarations, DECLARATION_HOOK);
1311 add_definition_db_callback(set_param_value, PARAM_VALUE);
1312 add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1313 add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1314 add_db_return_states_before(&db_limited_before);
1315 add_db_return_states_callback(LIMITED_VALUE, &db_param_limit_filter);
1316 add_db_return_states_callback(FILTER_VALUE, &db_param_limit_filter);
1317 add_db_return_states_callback(ADDED_VALUE, &db_param_add);
1318 add_db_return_states_after(&db_limited_after);
1319 }
1320
1321 void register_smatch_extra_late(int id)
1322 {
1323 add_hook(&match_dereferences, DEREF_HOOK);
1324 add_hook(&match_pointer_as_array, OP_HOOK);
1325 add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1326 add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1327 if (option_no_db)
1328 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1329 add_hook(&match_assign, ASSIGNMENT_HOOK);
1330 add_hook(&unop_expr, OP_HOOK);
1331 add_hook(&asm_expr, ASM_HOOK);
1332
1333 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1334 add_member_info_callback(my_id, struct_member_callback);
1335 add_returned_member_callback(my_id, returned_member_callback);
1336 }
Static analysis for C