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sval: introduce sval_min/max()
[smatch.git] / smatch_extra.c
blobb210c310ce937e6fead931106f0abdfad0a80662
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 static 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_str_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_str_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_str_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_type_max(get_type(iter_var));
231
232 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
233 return NULL;
234
235 switch (condition->op) {
236 case SPECIAL_NOTEQUAL:
237 case '<':
238 if (!sval_is_min(end))
239 end.value--;
240 break;
241 case SPECIAL_LTE:
242 break;
243 default:
244 return NULL;
245 }
246 if (sval_cmp(end, start) < 0)
247 return NULL;
248 estate = alloc_estate_range(start, end);
249 if (get_hard_max(condition->right, &dummy))
250 estate_set_hard_max(estate);
251 set_extra_expr_mod(iter_var, estate);
252 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
253 }
254
255 static struct sm_state *handle_canonical_for_dec(struct expression *iter_expr,
256 struct expression *condition)
257 {
258 struct expression *iter_var;
259 struct sm_state *sm;
260 struct smatch_state *estate;
261 sval_t start, end;
262
263 iter_var = iter_expr->unop;
264 sm = get_sm_state_expr(SMATCH_EXTRA, iter_var);
265 if (!sm)
266 return NULL;
267 if (!estate_get_single_value(sm->state, &start))
268 return NULL;
269 if (!get_implied_min(condition->right, &end))
270 end = sval_type_min(get_type(iter_var));
271 if (get_sm_state_expr(SMATCH_EXTRA, condition->left) != sm)
272 return NULL;
273
274 switch (condition->op) {
275 case SPECIAL_NOTEQUAL:
276 case '>':
277 if (!sval_is_min(end) && !sval_is_max(end))
278 end.value++;
279 break;
280 case SPECIAL_GTE:
281 break;
282 default:
283 return NULL;
284 }
285 if (sval_cmp(end, start) > 0)
286 return NULL;
287 estate = alloc_estate_range(end, start);
288 estate_set_hard_max(estate);
289 set_extra_expr_mod(iter_var, estate);
290 return get_sm_state_expr(SMATCH_EXTRA, iter_var);
291 }
292
293 static struct sm_state *handle_canonical_for_loops(struct statement *loop)
294 {
295 struct expression *iter_expr;
296 struct expression *condition;
297
298 if (!loop->iterator_post_statement)
299 return NULL;
300 if (loop->iterator_post_statement->type != STMT_EXPRESSION)
301 return NULL;
302 iter_expr = loop->iterator_post_statement->expression;
303 if (!loop->iterator_pre_condition)
304 return NULL;
305 if (loop->iterator_pre_condition->type != EXPR_COMPARE)
306 return NULL;
307 condition = loop->iterator_pre_condition;
308
309 if (iter_expr->op == SPECIAL_INCREMENT)
310 return handle_canonical_for_inc(iter_expr, condition);
311 if (iter_expr->op == SPECIAL_DECREMENT)
312 return handle_canonical_for_dec(iter_expr, condition);
313 return NULL;
314 }
315
316 struct sm_state *__extra_handle_canonical_loops(struct statement *loop, struct state_list **slist)
317 {
318 struct sm_state *ret;
319
320 __push_fake_cur_slist();
321 if (!loop->iterator_post_statement)
322 ret = handle_canonical_while_count_down(loop);
323 else
324 ret = handle_canonical_for_loops(loop);
325 *slist = __pop_fake_cur_slist();
326 return ret;
327 }
328
329 int __iterator_unchanged(struct sm_state *sm)
330 {
331 if (!sm)
332 return 0;
333 if (get_sm_state(my_id, sm->name, sm->sym) == sm)
334 return 1;
335 return 0;
336 }
337
338 static void while_count_down_after(struct sm_state *sm, struct expression *condition)
339 {
340 sval_t after_value;
341
342 /* paranoid checking. prolly not needed */
343 condition = strip_expr(condition);
344 if (!condition)
345 return;
346 if (condition->type != EXPR_PREOP && condition->type != EXPR_POSTOP)
347 return;
348 if (condition->op != SPECIAL_DECREMENT)
349 return;
350 after_value = estate_min(sm->state);
351 after_value.value--;
352 set_extra_mod(sm->name, sm->sym, alloc_estate_sval(after_value));
353 }
354
355 void __extra_pre_loop_hook_after(struct sm_state *sm,
356 struct statement *iterator,
357 struct expression *condition)
358 {
359 struct expression *iter_expr;
360 sval_t limit;
361 struct smatch_state *state;
362
363 if (!iterator) {
364 while_count_down_after(sm, condition);
365 return;
366 }
367
368 iter_expr = iterator->expression;
369
370 if (condition->type != EXPR_COMPARE)
371 return;
372 if (iter_expr->op == SPECIAL_INCREMENT) {
373 limit = sval_binop(estate_max(sm->state), '+',
374 sval_type_val(estate_type(sm->state), 1));
375 } else {
376 limit = sval_binop(estate_min(sm->state), '-',
377 sval_type_val(estate_type(sm->state), 1));
378 }
379 if (!estate_has_hard_max(sm->state) && !__has_breaks()) {
380 if (iter_expr->op == SPECIAL_INCREMENT)
381 state = alloc_estate_range(estate_min(sm->state), limit);
382 else
383 state = alloc_estate_range(limit, estate_max(sm->state));
384 } else {
385 state = alloc_estate_sval(limit);
386 }
387 if (!estate_has_hard_max(sm->state))
388 estate_clear_hard_max(state);
389 set_extra_mod(sm->name, sm->sym, state);
390 }
391
392 static struct state_list *unmatched_slist;
393 static struct smatch_state *unmatched_state(struct sm_state *sm)
394 {
395 struct smatch_state *state;
396
397 if (unmatched_slist) {
398 state = get_state_slist(unmatched_slist, SMATCH_EXTRA, sm->name, sm->sym);
399 if (state)
400 return state;
401 }
402 return alloc_estate_whole(estate_type(sm->state));
403 }
404
405 static void match_function_call(struct expression *expr)
406 {
407 struct expression *arg;
408 struct expression *tmp;
409
410 FOR_EACH_PTR(expr->args, arg) {
411 tmp = strip_expr(arg);
412 if (tmp->type == EXPR_PREOP && tmp->op == '&') {
413 remove_from_equiv_expr(tmp->unop);
414 set_state_expr(SMATCH_EXTRA, tmp->unop, alloc_estate_whole(get_type(tmp->unop)));
415 }
416 } END_FOR_EACH_PTR(arg);
417 }
418
419 static int types_equiv_or_pointer(struct symbol *one, struct symbol *two)
420 {
421 if (!one || !two)
422 return 0;
423 if (one->type == SYM_PTR && two->type == SYM_PTR)
424 return 1;
425 return types_equiv(one, two);
426 }
427
428 static void match_assign(struct expression *expr)
429 {
430 struct range_list *rl = NULL;
431 struct expression *left;
432 struct expression *right;
433 struct symbol *right_sym;
434 char *right_name = NULL;
435 struct symbol *sym;
436 char *name;
437 sval_t value;
438 int known;
439 sval_t right_min, right_max;
440 sval_t tmp;
441
442 if (is_condition(expr->right))
443 return;
444 left = strip_expr(expr->left);
445 name = expr_to_str_sym(left, &sym);
446 if (!name)
447 return;
448 right = strip_parens(expr->right);
449 while (right->type == EXPR_ASSIGNMENT && right->op == '=')
450 right = strip_parens(right->left);
451
452 if (expr->op == '=' && right->type == EXPR_CALL)
453 goto free; /* these are handled in smatch_function_hooks.c */
454
455 right_name = expr_to_str_sym(right, &right_sym);
456 if (expr->op == '=' && right_name && right_sym &&
457 types_equiv_or_pointer(get_type(expr->left), get_type(expr->right))) {
458 set_equiv(left, right);
459 goto free;
460 }
461
462 right_min = sval_type_min(get_type(expr->right));
463 right_max = sval_type_max(get_type(expr->right));
464
465 known = get_implied_value(right, &value);
466 switch (expr->op) {
467 case '=': {
468 struct smatch_state *state;
469
470 if (get_implied_rl(right, &rl)) {
471 rl = cast_rl(get_type(expr->left), rl);
472 state = alloc_estate_rl(rl);
473 if (get_hard_max(right, &tmp))
474 estate_set_hard_max(state);
475 } else {
476 rl = alloc_whole_rl(get_type(right));
477 rl = cast_rl(get_type(expr->left), rl);
478 state = alloc_estate_rl(rl);
479 }
480 set_extra_mod(name, sym, state);
481 goto free;
482 }
483 case SPECIAL_ADD_ASSIGN:
484 if (get_implied_min(left, &tmp)) {
485 if (known)
486 right_min = sval_binop(tmp, '+', value);
487 else
488 right_min = tmp;
489 }
490 if (!inside_loop() && known && get_implied_max(left, &tmp))
491 right_max = sval_binop(tmp, '+', value);
492 break;
493 case SPECIAL_SUB_ASSIGN:
494 if (get_implied_max(left, &tmp)) {
495 if (known)
496 right_max = sval_binop(tmp, '-', value);
497 else
498 right_max = tmp;
499 }
500 if (!inside_loop() && known && get_implied_min(left, &tmp))
501 right_min = sval_binop(tmp, '-', value);
502 break;
503 }
504 if (!sval_is_min(right_min) || !sval_is_max(right_max))
505 rl = cast_rl(get_type(expr->left), alloc_rl(right_min, right_max));
506 else
507 rl = alloc_whole_rl(get_type(expr->left));
508 set_extra_mod(name, sym, alloc_estate_rl(rl));
509 free:
510 free_string(right_name);
511 free_string(name);
512 }
513
514 static void reset_struct_members(struct sm_state *sm)
515 {
516 set_extra_mod(sm->name, sm->sym, alloc_estate_whole(estate_type(sm->state)));
517 }
518
519 static struct smatch_state *increment_state(struct smatch_state *state)
520 {
521 sval_t min = estate_min(state);
522 sval_t max = estate_max(state);
523
524 if (!estate_rl(state))
525 return NULL;
526
527 if (inside_loop())
528 max = sval_type_max(max.type);
529
530 if (!sval_is_min(min) && !sval_is_max(min))
531 min.value++;
532 if (!sval_is_min(max) && !sval_is_max(max))
533 max.value++;
534 return alloc_estate_range(min, max);
535 }
536
537 static struct smatch_state *decrement_state(struct smatch_state *state)
538 {
539 sval_t min = estate_min(state);
540 sval_t max = estate_max(state);
541
542 if (!estate_rl(state))
543 return NULL;
544
545 if (inside_loop())
546 min = sval_type_min(min.type);
547
548 if (!sval_is_min(min) && !sval_is_max(min))
549 min.value--;
550 if (!sval_is_min(max) && !sval_is_max(max))
551 max.value--;
552 return alloc_estate_range(min, max);
553 }
554
555 static void unop_expr(struct expression *expr)
556 {
557 struct smatch_state *state;
558
559 if (expr->smatch_flags & Handled)
560 return;
561
562 switch (expr->op) {
563 case SPECIAL_INCREMENT:
564 state = get_state_expr(SMATCH_EXTRA, expr->unop);
565 state = increment_state(state);
566 if (!state)
567 state = alloc_estate_whole(get_type(expr));
568 set_extra_expr_mod(expr->unop, state);
569 break;
570 case SPECIAL_DECREMENT:
571 state = get_state_expr(SMATCH_EXTRA, expr->unop);
572 state = decrement_state(state);
573 if (!state)
574 state = alloc_estate_whole(get_type(expr));
575 set_extra_expr_mod(expr->unop, state);
576 break;
577 default:
578 return;
579 }
580 }
581
582 static void asm_expr(struct statement *stmt)
583 {
584
585 struct expression *expr;
586 int state = 0;
587
588 FOR_EACH_PTR(stmt->asm_outputs, expr) {
589 switch (state) {
590 case 0: /* identifier */
591 case 1: /* constraint */
592 state++;
593 continue;
594 case 2: /* expression */
595 state = 0;
596 set_extra_expr_mod(expr, alloc_estate_whole(get_type(expr)));
597 continue;
598 }
599 } END_FOR_EACH_PTR(expr);
600 }
601
602 static void delete_state_tracker(struct tracker *t)
603 {
604 remove_from_equiv(t->name, t->sym);
605 delete_state(t->owner, t->name, t->sym);
606 }
607
608 static void scoped_state_extra(const char *name, struct symbol *sym)
609 {
610 struct tracker *t;
611
612 t = alloc_tracker(SMATCH_EXTRA, name, sym);
613 add_scope_hook((scope_hook *)&delete_state_tracker, t);
614 }
615
616 static void match_declarations(struct symbol *sym)
617 {
618 const char *name;
619
620 if (sym->ident) {
621 name = sym->ident->name;
622 if (!sym->initializer) {
623 set_state(SMATCH_EXTRA, name, sym, alloc_estate_whole(get_real_base_type(sym)));
624 scoped_state_extra(name, sym);
625 }
626 }
627 }
628
629 static void check_dereference(struct expression *expr)
630 {
631 set_extra_expr_nomod(expr, alloc_estate_range(valid_ptr_min_sval, valid_ptr_max_sval));
632 }
633
634 static void match_dereferences(struct expression *expr)
635 {
636 if (expr->type != EXPR_PREOP)
637 return;
638 check_dereference(expr->unop);
639 }
640
641 static void match_pointer_as_array(struct expression *expr)
642 {
643 if (!is_array(expr))
644 return;
645 check_dereference(expr->unop->left);
646 }
647
648 static void set_param_dereferenced(struct expression *arg, char *unused)
649 {
650 check_dereference(arg);
651 }
652
653 static void match_function_def(struct symbol *sym)
654 {
655 struct symbol *arg;
656
657 FOR_EACH_PTR(sym->ctype.base_type->arguments, arg) {
658 if (!arg->ident)
659 continue;
660 set_state(my_id, arg->ident->name, arg, alloc_estate_whole(get_real_base_type(arg)));
661 } END_FOR_EACH_PTR(arg);
662 }
663
664 static int match_func_comparison(struct expression *expr)
665 {
666 struct expression *left = strip_expr(expr->left);
667 struct expression *right = strip_expr(expr->right);
668 sval_t sval;
669
670 if (left->type == EXPR_CALL) {
671 if (!get_implied_value(right, &sval))
672 return 1;
673 function_comparison(expr->op, left, sval, 1);
674 return 1;
675 }
676
677 if (right->type == EXPR_CALL) {
678 if (!get_implied_value(left, &sval))
679 return 1;
680 function_comparison(expr->op, right, sval, 0);
681 return 1;
682 }
683
684 return 0;
685 }
686
687 static sval_t add_one(sval_t sval)
688 {
689 sval.value++;
690 return sval;
691 }
692
693 static sval_t sub_one(sval_t sval)
694 {
695 sval.value--;
696 return sval;
697 }
698
699 static void match_comparison(struct expression *expr)
700 {
701 struct expression *left = strip_expr(expr->left);
702 struct expression *right = strip_expr(expr->right);
703 struct symbol *type;
704 struct range_list *left_orig;
705 struct range_list *left_true;
706 struct range_list *left_false;
707 struct range_list *right_orig;
708 struct range_list *right_true;
709 struct range_list *right_false;
710 struct smatch_state *left_true_state;
711 struct smatch_state *left_false_state;
712 struct smatch_state *right_true_state;
713 struct smatch_state *right_false_state;
714 sval_t min, max, dummy;
715 int left_postop = 0;
716 int right_postop = 0;
717
718 if (match_func_comparison(expr))
719 return;
720
721 if (left->op == SPECIAL_INCREMENT || left->op == SPECIAL_DECREMENT) {
722 if (left->type == EXPR_POSTOP) {
723 left->smatch_flags |= Handled;
724 left_postop = left->op;
725 }
726 left = strip_expr(left->unop);
727 }
728 while (left->type == EXPR_ASSIGNMENT)
729 left = strip_expr(left->left);
730
731 if (right->op == SPECIAL_INCREMENT || right->op == SPECIAL_DECREMENT) {
732 if (right->type == EXPR_POSTOP) {
733 right->smatch_flags |= Handled;
734 right_postop = right->op;
735 }
736 right = strip_expr(right->unop);
737 }
738
739 type = get_type(expr);
740 if (!type)
741 type = &llong_ctype;
742
743 if (get_implied_rl(left, &left_orig)) {
744 left_orig = cast_rl(type, left_orig);
745 } else {
746 min = sval_type_min(get_type(left));
747 max = sval_type_max(get_type(left));
748 left_orig = cast_rl(type, alloc_rl(min, max));
749 }
750
751 if (get_implied_rl(right, &right_orig)) {
752 right_orig = cast_rl(type, right_orig);
753 } else {
754 min = sval_type_min(get_type(right));
755 max = sval_type_max(get_type(right));
756 right_orig = cast_rl(type, alloc_rl(min, max));
757 }
758 min = sval_type_min(type);
759 max = sval_type_max(type);
760
761 left_true = clone_rl(left_orig);
762 left_false = clone_rl(left_orig);
763 right_true = clone_rl(right_orig);
764 right_false = clone_rl(right_orig);
765
766 switch (expr->op) {
767 case '<':
768 case SPECIAL_UNSIGNED_LT:
769 left_true = remove_range(left_orig, rl_max(right_orig), max);
770 if (!sval_is_min(rl_min(right_orig))) {
771 left_false = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
772 }
773
774 right_true = remove_range(right_orig, min, rl_min(left_orig));
775 if (!sval_is_max(rl_max(left_orig)))
776 right_false = remove_range(right_orig, add_one(rl_max(left_orig)), max);
777 break;
778 case SPECIAL_UNSIGNED_LTE:
779 case SPECIAL_LTE:
780 if (!sval_is_max(rl_max(right_orig)))
781 left_true = remove_range(left_orig, add_one(rl_max(right_orig)), max);
782 left_false = remove_range(left_orig, min, rl_min(right_orig));
783
784 if (!sval_is_min(rl_min(left_orig)))
785 right_true = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
786 right_false = remove_range(right_orig, rl_max(left_orig), max);
787
788 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
789 left_false = remove_range(left_false, rl_min(left_orig), rl_min(left_orig));
790 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
791 right_false = remove_range(right_false, rl_max(left_orig), rl_max(left_orig));
792 break;
793 case SPECIAL_EQUAL:
794 if (!sval_is_max(rl_max(right_orig))) {
795 left_true = remove_range(left_true, add_one(rl_max(right_orig)), max);
796 }
797 if (!sval_is_min(rl_min(right_orig))) {
798 left_true = remove_range(left_true, min, sub_one(rl_min(right_orig)));
799 }
800 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
801 left_false = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
802
803 if (!sval_is_max(rl_max(left_orig)))
804 right_true = remove_range(right_true, add_one(rl_max(left_orig)), max);
805 if (!sval_is_min(rl_min(left_orig)))
806 right_true = remove_range(right_true, min, sub_one(rl_min(left_orig)));
807 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
808 right_false = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
809 break;
810 case SPECIAL_UNSIGNED_GTE:
811 case SPECIAL_GTE:
812 if (!sval_is_min(rl_min(right_orig)))
813 left_true = remove_range(left_orig, min, sub_one(rl_min(right_orig)));
814 left_false = remove_range(left_orig, rl_max(right_orig), max);
815
816 if (!sval_is_max(rl_max(left_orig)))
817 right_true = remove_range(right_orig, add_one(rl_max(left_orig)), max);
818 right_false = remove_range(right_orig, min, rl_min(left_orig));
819
820 if (sval_cmp(rl_min(left_orig), rl_min(right_orig)) == 0)
821 right_false = remove_range(right_false, rl_min(left_orig), rl_min(left_orig));
822 if (sval_cmp(rl_max(left_orig), rl_max(right_orig)) == 0)
823 left_false = remove_range(left_false, rl_max(left_orig), rl_max(left_orig));
824 break;
825 case '>':
826 case SPECIAL_UNSIGNED_GT:
827 left_true = remove_range(left_orig, min, rl_min(right_orig));
828 if (!sval_is_max(rl_max(right_orig)))
829 left_false = remove_range(left_orig, add_one(rl_max(right_orig)), max);
830
831 right_true = remove_range(right_orig, rl_max(left_orig), max);
832 if (!sval_is_min(rl_min(left_orig)))
833 right_false = remove_range(right_orig, min, sub_one(rl_min(left_orig)));
834 break;
835 case SPECIAL_NOTEQUAL:
836 if (!sval_is_max(rl_max(right_orig)))
837 left_false = remove_range(left_false, add_one(rl_max(right_orig)), max);
838 if (!sval_is_min(rl_min(right_orig)))
839 left_false = remove_range(left_false, min, sub_one(rl_min(right_orig)));
840 if (sval_cmp(rl_min(right_orig), rl_max(right_orig)) == 0)
841 left_true = remove_range(left_orig, rl_min(right_orig), rl_min(right_orig));
842
843 if (!sval_is_max(rl_max(left_orig)))
844 right_false = remove_range(right_false, add_one(rl_max(left_orig)), max);
845 if (!sval_is_min(rl_min(left_orig)))
846 right_false = remove_range(right_false, min, sub_one(rl_min(left_orig)));
847 if (sval_cmp(rl_min(left_orig), rl_max(left_orig)) == 0)
848 right_true = remove_range(right_orig, rl_min(left_orig), rl_min(left_orig));
849 break;
850 default:
851 return;
852 }
853
854 left_true_state = alloc_estate_rl(cast_rl(get_type(left), left_true));
855 left_false_state = alloc_estate_rl(cast_rl(get_type(left), left_false));
856 right_true_state = alloc_estate_rl(cast_rl(get_type(right), right_true));
857 right_false_state = alloc_estate_rl(cast_rl(get_type(right), right_false));
858
859 switch (expr->op) {
860 case '<':
861 case SPECIAL_UNSIGNED_LT:
862 case SPECIAL_UNSIGNED_LTE:
863 case SPECIAL_LTE:
864 if (get_hard_max(right, &dummy))
865 estate_set_hard_max(left_true_state);
866 if (get_hard_max(left, &dummy))
867 estate_set_hard_max(right_false_state);
868 break;
869 case '>':
870 case SPECIAL_UNSIGNED_GT:
871 case SPECIAL_UNSIGNED_GTE:
872 case SPECIAL_GTE:
873 if (get_hard_max(left, &dummy))
874 estate_set_hard_max(right_true_state);
875 if (get_hard_max(right, &dummy))
876 estate_set_hard_max(left_false_state);
877 break;
878 }
879
880 if (get_hard_max(left, &dummy)) {
881 estate_set_hard_max(left_true_state);
882 estate_set_hard_max(left_false_state);
883 }
884 if (get_hard_max(right, &dummy)) {
885 estate_set_hard_max(right_true_state);
886 estate_set_hard_max(right_false_state);
887 }
888
889 if (left_postop == SPECIAL_INCREMENT) {
890 left_true_state = increment_state(left_true_state);
891 left_false_state = increment_state(left_false_state);
892 }
893 if (left_postop == SPECIAL_DECREMENT) {
894 left_true_state = decrement_state(left_true_state);
895 left_false_state = decrement_state(left_false_state);
896 }
897 if (right_postop == SPECIAL_INCREMENT) {
898 right_true_state = increment_state(right_true_state);
899 right_false_state = increment_state(right_false_state);
900 }
901 if (right_postop == SPECIAL_DECREMENT) {
902 right_true_state = decrement_state(right_true_state);
903 right_false_state = decrement_state(right_false_state);
904 }
905
906 set_extra_expr_true_false(left, left_true_state, left_false_state);
907 set_extra_expr_true_false(right, right_true_state, right_false_state);
908 }
909
910 /* this is actually hooked from smatch_implied.c... it's hacky, yes */
911 void __extra_match_condition(struct expression *expr)
912 {
913 struct symbol *sym;
914 char *name;
915 struct smatch_state *pre_state;
916 struct smatch_state *true_state;
917 struct smatch_state *false_state;
918
919 expr = strip_expr(expr);
920 switch (expr->type) {
921 case EXPR_CALL:
922 function_comparison(SPECIAL_NOTEQUAL, expr, ll_to_sval(0), 1);
923 return;
924 case EXPR_PREOP:
925 case EXPR_SYMBOL:
926 case EXPR_DEREF: {
927 sval_t zero;
928
929 zero = sval_blank(expr);
930 zero.value = 0;
931
932 name = expr_to_str_sym(expr, &sym);
933 if (!name)
934 return;
935 pre_state = get_state(my_id, name, sym);
936 true_state = estate_filter_sval(pre_state, zero);
937 if (possibly_true(expr, SPECIAL_EQUAL, zero_expr()))
938 false_state = alloc_estate_sval(zero);
939 else
940 false_state = alloc_estate_empty();
941 set_extra_true_false(name, sym, true_state, false_state);
942 free_string(name);
943 return;
944 }
945 case EXPR_COMPARE:
946 match_comparison(expr);
947 return;
948 case EXPR_ASSIGNMENT:
949 __extra_match_condition(expr->left);
950 return;
951 }
952 }
953
954 /* returns 1 if it is not possible for expr to be value, otherwise returns 0 */
955 int implied_not_equal(struct expression *expr, long long val)
956 {
957 return !possibly_false(expr, SPECIAL_NOTEQUAL, value_expr(val));
958 }
959
960 static void struct_member_callback(char *fn, char *global_static, int param, char *printed_name, struct smatch_state *state)
961 {
962 if (estate_is_whole(state))
963 return;
964 sm_msg("info: passes param_value '%s' %d '%s' %s %s", fn, param, printed_name, state->name, global_static);
965 }
966
967 static void db_limited_before(void)
968 {
969 unmatched_slist = clone_slist(__get_cur_slist());
970 }
971
972 static void db_limited_after(void)
973 {
974 free_slist(&unmatched_slist);
975 }
976
977 static char *get_variable_from_key(struct expression *arg, char *key, struct symbol **sym)
978 {
979 char buf[256];
980 char *tmp;
981
982 if (strcmp(key, "$$") == 0)
983 return expr_to_str_sym(arg, sym);
984
985 if (strcmp(key, "*$$") == 0) {
986 if (arg->type == EXPR_PREOP && arg->op == '&') {
987 arg = strip_expr(arg->unop);
988 return expr_to_str_sym(arg, sym);
989 } else {
990 tmp = expr_to_str_sym(arg, sym);
991 if (!tmp)
992 return NULL;
993 snprintf(buf, sizeof(buf), "*%s", tmp);
994 free_string(tmp);
995 return alloc_string(buf);
996 }
997 }
998
999 if (arg->type == EXPR_PREOP && arg->op == '&') {
1000 arg = strip_expr(arg->unop);
1001 tmp = expr_to_str_sym(arg, sym);
1002 if (!tmp)
1003 return NULL;
1004 snprintf(buf, sizeof(buf), "%s.%s", tmp, key + 4);
1005 return alloc_string(buf);
1006 }
1007
1008 tmp = expr_to_str_sym(arg, sym);
1009 if (!tmp)
1010 return NULL;
1011 snprintf(buf, sizeof(buf), "%s%s", tmp, key + 2);
1012 free_string(tmp);
1013 return alloc_string(buf);
1014 }
1015
1016 static void db_param_limit_filter(struct expression *expr, int param, char *key, char *value)
1017 {
1018 struct expression *arg;
1019 char *name;
1020 struct symbol *sym;
1021 struct sm_state *sm;
1022 struct symbol *type;
1023 struct range_list *rl;
1024 struct range_list *limit;
1025 struct range_list *new;
1026
1027 while (expr->type == EXPR_ASSIGNMENT)
1028 expr = strip_expr(expr->right);
1029 if (expr->type != EXPR_CALL)
1030 return;
1031
1032 arg = get_argument_from_call_expr(expr->args, param);
1033 if (!arg)
1034 return;
1035
1036 name = get_variable_from_key(arg, key, &sym);
1037 if (!name || !sym)
1038 goto free;
1039
1040 sm = get_sm_state(SMATCH_EXTRA, name, sym);
1041 type = get_member_type_from_key(arg, key);
1042 if (sm)
1043 rl = estate_rl(sm->state);
1044 else
1045 rl = alloc_whole_rl(type);
1046
1047 str_to_rl(type, value, &limit);
1048 new = rl_intersection(rl, limit);
1049
1050 /* We want to preserve the implications here */
1051 if (sm && rl_equiv(estate_rl(sm->state), new))
1052 __set_sm(sm);
1053 else
1054 set_extra_nomod(name, sym, alloc_estate_rl(new));
1055
1056 free:
1057 free_string(name);
1058 }
1059
1060 static void db_param_add(struct expression *expr, int param, char *key, char *value)
1061 {
1062 struct expression *arg;
1063 char *name;
1064 struct symbol *sym;
1065 struct symbol *type;
1066 struct smatch_state *state;
1067 struct range_list *added = NULL;
1068 struct range_list *new;
1069
1070 while (expr->type == EXPR_ASSIGNMENT)
1071 expr = strip_expr(expr->right);
1072 if (expr->type != EXPR_CALL)
1073 return;
1074
1075 arg = get_argument_from_call_expr(expr->args, param);
1076 if (!arg)
1077 return;
1078 name = get_variable_from_key(arg, key, &sym);
1079 if (!name || !sym)
1080 goto free;
1081
1082 type = get_member_type_from_key(arg, key);
1083 state = get_state(SMATCH_EXTRA, name, sym);
1084 if (state) {
1085 str_to_rl(type, value, &added);
1086 new = rl_union(estate_rl(state), added);
1087 } else {
1088 new = alloc_whole_rl(type);
1089 }
1090
1091 set_extra_mod(name, sym, alloc_estate_rl(new));
1092 free:
1093 free_string(name);
1094 }
1095
1096 static void db_returned_states_param(struct expression *expr, int param, char *key, char *value)
1097 {
1098 struct expression *arg;
1099 struct symbol *type;
1100 struct range_list *rl;
1101 char member_name[256];
1102 char *name;
1103 struct symbol *sym;
1104
1105 while (expr->type == EXPR_ASSIGNMENT)
1106 expr = strip_expr(expr->right);
1107 if (expr->type != EXPR_CALL)
1108 return;
1109 arg = get_argument_from_call_expr(expr->args, param);
1110 arg = strip_expr(arg);
1111 if (!arg)
1112 return;
1113
1114 if (strcmp(key, "*$$") == 0) {
1115 struct symbol *sym;
1116 char buf[256];
1117 char *name;
1118
1119 if (arg->type == EXPR_PREOP && arg->op == '&') {
1120 arg = strip_expr(arg->unop);
1121 name = expr_to_str_sym(arg, &sym);
1122 } else {
1123 char *tmp = expr_to_str_sym(arg, &sym);
1124
1125 if (!tmp)
1126 return;
1127 snprintf(buf, sizeof(buf), "*%s", tmp);
1128 name = alloc_string(buf);
1129 free_string(tmp);
1130 }
1131 if (!name || !sym) {
1132 free_string(name);
1133 return;
1134 }
1135 type = get_type(arg);
1136 str_to_rl(type, value, &rl);
1137 set_extra_mod(name, sym, alloc_estate_rl(rl));
1138 free_string(name);
1139 return;
1140 }
1141
1142 if (arg->type == EXPR_PREOP && arg->op == '&') {
1143 arg = strip_expr(arg->unop);
1144 name = expr_to_str_sym(arg, &sym);
1145 if (!name || !sym)
1146 goto free;
1147 snprintf(member_name, sizeof(member_name), "%s.%s", name, key + 4);
1148 } else {
1149 name = expr_to_str_sym(arg, &sym);
1150 if (!name || !sym)
1151 goto free;
1152 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1153 }
1154 type = get_member_type_from_key(arg, key);
1155 if (!type)
1156 goto free;
1157 str_to_rl(type, value, &rl);
1158 set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1159 free:
1160 free_string(name);
1161 }
1162
1163 static void db_returned_member_info(struct expression *expr, int param, char *key, char *value)
1164 {
1165 struct symbol *type;
1166 struct symbol *sym;
1167 char *name;
1168 char member_name[256];
1169 struct range_list *rl;
1170
1171 if (expr->type != EXPR_ASSIGNMENT)
1172 return;
1173
1174 name = expr_to_str_sym(expr->left, &sym);
1175 if (!name || !sym)
1176 goto free;
1177 snprintf(member_name, sizeof(member_name), "%s%s", name, key + 2);
1178 type = get_member_type_from_key(expr->left, key);
1179 if (!type)
1180 return;
1181 str_to_rl(type, value, &rl);
1182 set_extra_mod(member_name, sym, alloc_estate_rl(rl));
1183
1184 free:
1185 free_string(name);
1186 }
1187
1188 static void returned_member_callback(int return_id, char *return_ranges, char *printed_name, struct smatch_state *state)
1189 {
1190 if (estate_is_whole(state))
1191 return;
1192 sm_msg("info: return_value %d '%s' '%s' '%s' %s", return_id,
1193 return_ranges, printed_name, state->name, global_static());
1194 }
1195
1196 static void match_call_info(struct expression *expr)
1197 {
1198 struct range_list *rl = NULL;
1199 struct expression *arg;
1200 struct symbol *type;
1201 char *name;
1202 int i = 0;
1203
1204 name = get_fnptr_name(expr->fn);
1205 if (!name)
1206 return;
1207
1208 FOR_EACH_PTR(expr->args, arg) {
1209 type = get_arg_type(expr->fn, i);
1210
1211 if (get_implied_rl(arg, &rl))
1212 rl = cast_rl(type, rl);
1213 else
1214 rl = alloc_whole_rl(type);
1215
1216 sm_msg("info: passes param_value '%s' %d '$$' %s %s",
1217 name, i, show_rl(rl),
1218 is_static(expr->fn) ? "static" : "global");
1219 i++;
1220 } END_FOR_EACH_PTR(arg);
1221
1222 free_string(name);
1223 }
1224
1225 static void set_param_value(const char *name, struct symbol *sym, char *key, char *value)
1226 {
1227 struct range_list *rl = NULL;
1228 struct smatch_state *state;
1229 struct symbol *type;
1230 char fullname[256];
1231
1232 if (strncmp(key, "$$", 2))
1233 return;
1234
1235 snprintf(fullname, 256, "%s%s", name, key + 2);
1236 type = get_member_type_from_key(symbol_expression(sym), key);
1237 str_to_rl(type, value, &rl);
1238 state = alloc_estate_rl(rl);
1239 set_state(SMATCH_EXTRA, fullname, sym, state);
1240 }
1241
1242 void register_smatch_extra(int id)
1243 {
1244 my_id = id;
1245
1246 add_merge_hook(my_id, &merge_estates);
1247 add_unmatched_state_hook(my_id, &unmatched_state);
1248 add_hook(&match_function_def, FUNC_DEF_HOOK);
1249 add_hook(&match_declarations, DECLARATION_HOOK);
1250 add_definition_db_callback(set_param_value, PARAM_VALUE);
1251 add_db_return_states_callback(RETURN_VALUE, &db_returned_member_info);
1252 add_db_return_states_callback(PARAM_VALUE, &db_returned_states_param);
1253 add_db_return_states_before(&db_limited_before);
1254 add_db_return_states_callback(LIMITED_VALUE, &db_param_limit_filter);
1255 add_db_return_states_callback(FILTER_VALUE, &db_param_limit_filter);
1256 add_db_return_states_callback(ADDED_VALUE, &db_param_add);
1257 add_db_return_states_after(&db_limited_after);
1258 }
1259
1260 void register_smatch_extra_late(int id)
1261 {
1262 add_hook(&match_dereferences, DEREF_HOOK);
1263 add_hook(&match_pointer_as_array, OP_HOOK);
1264 add_db_fn_call_callback(DEREFERENCE, &set_param_dereferenced);
1265 add_indirect_modification_hook(SMATCH_EXTRA, reset_struct_members);
1266 if (option_no_db)
1267 add_hook(&match_function_call, FUNCTION_CALL_HOOK);
1268 add_hook(&match_assign, ASSIGNMENT_HOOK);
1269 add_hook(&unop_expr, OP_HOOK);
1270 add_hook(&asm_expr, ASM_HOOK);
1271
1272 if (option_info) {
1273 add_hook(&match_call_info, FUNCTION_CALL_HOOK);
1274 add_member_info_callback(my_id, struct_member_callback);
1275 add_returned_member_callback(my_id, returned_member_callback);
1276 }
1277 }
Static analysis for C