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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
4 */
5
6#include <ctype.h>
7#include <errno.h>
8#include <stdio.h>
9#include <stdlib.h>
10#include <string.h>
11
12#include "lkc.h"
13
14#define DEBUG_EXPR 0
15
16static int expr_eq(struct expr *e1, struct expr *e2);
17static struct expr *expr_eliminate_yn(struct expr *e);
18
19struct expr *expr_alloc_symbol(struct symbol *sym)
20{
21 struct expr *e = xcalloc(1, sizeof(*e));
22 e->type = E_SYMBOL;
23 e->left.sym = sym;
24 return e;
25}
26
27struct expr *expr_alloc_one(enum expr_type type, struct expr *ce)
28{
29 struct expr *e = xcalloc(1, sizeof(*e));
30 e->type = type;
31 e->left.expr = ce;
32 return e;
33}
34
35struct expr *expr_alloc_two(enum expr_type type, struct expr *e1, struct expr *e2)
36{
37 struct expr *e = xcalloc(1, sizeof(*e));
38 e->type = type;
39 e->left.expr = e1;
40 e->right.expr = e2;
41 return e;
42}
43
44struct expr *expr_alloc_comp(enum expr_type type, struct symbol *s1, struct symbol *s2)
45{
46 struct expr *e = xcalloc(1, sizeof(*e));
47 e->type = type;
48 e->left.sym = s1;
49 e->right.sym = s2;
50 return e;
51}
52
53struct expr *expr_alloc_and(struct expr *e1, struct expr *e2)
54{
55 if (!e1)
56 return e2;
57 return e2 ? expr_alloc_two(E_AND, e1, e2) : e1;
58}
59
60struct expr *expr_alloc_or(struct expr *e1, struct expr *e2)
61{
62 if (!e1)
63 return e2;
64 return e2 ? expr_alloc_two(E_OR, e1, e2) : e1;
65}
66
67struct expr *expr_copy(const struct expr *org)
68{
69 struct expr *e;
70
71 if (!org)
72 return NULL;
73
74 e = xmalloc(sizeof(*org));
75 memcpy(e, org, sizeof(*org));
76 switch (org->type) {
77 case E_SYMBOL:
78 e->left = org->left;
79 break;
80 case E_NOT:
81 e->left.expr = expr_copy(org->left.expr);
82 break;
83 case E_EQUAL:
84 case E_GEQ:
85 case E_GTH:
86 case E_LEQ:
87 case E_LTH:
88 case E_UNEQUAL:
89 e->left.sym = org->left.sym;
90 e->right.sym = org->right.sym;
91 break;
92 case E_AND:
93 case E_OR:
94 case E_LIST:
95 e->left.expr = expr_copy(org->left.expr);
96 e->right.expr = expr_copy(org->right.expr);
97 break;
98 default:
99 fprintf(stderr, "can't copy type %d\n", e->type);
100 free(e);
101 e = NULL;
102 break;
103 }
104
105 return e;
106}
107
108void expr_free(struct expr *e)
109{
110 if (!e)
111 return;
112
113 switch (e->type) {
114 case E_SYMBOL:
115 break;
116 case E_NOT:
117 expr_free(e->left.expr);
118 break;
119 case E_EQUAL:
120 case E_GEQ:
121 case E_GTH:
122 case E_LEQ:
123 case E_LTH:
124 case E_UNEQUAL:
125 break;
126 case E_OR:
127 case E_AND:
128 expr_free(e->left.expr);
129 expr_free(e->right.expr);
130 break;
131 default:
132 fprintf(stderr, "how to free type %d?\n", e->type);
133 break;
134 }
135 free(e);
136}
137
138static int trans_count;
139
140#define e1 (*ep1)
141#define e2 (*ep2)
142
143/*
144 * expr_eliminate_eq() helper.
145 *
146 * Walks the two expression trees given in 'ep1' and 'ep2'. Any node that does
147 * not have type 'type' (E_OR/E_AND) is considered a leaf, and is compared
148 * against all other leaves. Two equal leaves are both replaced with either 'y'
149 * or 'n' as appropriate for 'type', to be eliminated later.
150 */
151static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct expr **ep2)
152{
153 /* Recurse down to leaves */
154
155 if (e1->type == type) {
156 __expr_eliminate_eq(type, &e1->left.expr, &e2);
157 __expr_eliminate_eq(type, &e1->right.expr, &e2);
158 return;
159 }
160 if (e2->type == type) {
161 __expr_eliminate_eq(type, &e1, &e2->left.expr);
162 __expr_eliminate_eq(type, &e1, &e2->right.expr);
163 return;
164 }
165
166 /* e1 and e2 are leaves. Compare them. */
167
168 if (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
169 e1->left.sym == e2->left.sym &&
170 (e1->left.sym == &symbol_yes || e1->left.sym == &symbol_no))
171 return;
172 if (!expr_eq(e1, e2))
173 return;
174
175 /* e1 and e2 are equal leaves. Prepare them for elimination. */
176
177 trans_count++;
178 expr_free(e1); expr_free(e2);
179 switch (type) {
180 case E_OR:
181 e1 = expr_alloc_symbol(&symbol_no);
182 e2 = expr_alloc_symbol(&symbol_no);
183 break;
184 case E_AND:
185 e1 = expr_alloc_symbol(&symbol_yes);
186 e2 = expr_alloc_symbol(&symbol_yes);
187 break;
188 default:
189 ;
190 }
191}
192
193/*
194 * Rewrites the expressions 'ep1' and 'ep2' to remove operands common to both.
195 * Example reductions:
196 *
197 * ep1: A && B -> ep1: y
198 * ep2: A && B && C -> ep2: C
199 *
200 * ep1: A || B -> ep1: n
201 * ep2: A || B || C -> ep2: C
202 *
203 * ep1: A && (B && FOO) -> ep1: FOO
204 * ep2: (BAR && B) && A -> ep2: BAR
205 *
206 * ep1: A && (B || C) -> ep1: y
207 * ep2: (C || B) && A -> ep2: y
208 *
209 * Comparisons are done between all operands at the same "level" of && or ||.
210 * For example, in the expression 'e1 && (e2 || e3) && (e4 || e5)', the
211 * following operands will be compared:
212 *
213 * - 'e1', 'e2 || e3', and 'e4 || e5', against each other
214 * - e2 against e3
215 * - e4 against e5
216 *
217 * Parentheses are irrelevant within a single level. 'e1 && (e2 && e3)' and
218 * '(e1 && e2) && e3' are both a single level.
219 *
220 * See __expr_eliminate_eq() as well.
221 */
222void expr_eliminate_eq(struct expr **ep1, struct expr **ep2)
223{
224 if (!e1 || !e2)
225 return;
226 switch (e1->type) {
227 case E_OR:
228 case E_AND:
229 __expr_eliminate_eq(e1->type, ep1, ep2);
230 default:
231 ;
232 }
233 if (e1->type != e2->type) switch (e2->type) {
234 case E_OR:
235 case E_AND:
236 __expr_eliminate_eq(e2->type, ep1, ep2);
237 default:
238 ;
239 }
240 e1 = expr_eliminate_yn(e1);
241 e2 = expr_eliminate_yn(e2);
242}
243
244#undef e1
245#undef e2
246
247/*
248 * Returns true if 'e1' and 'e2' are equal, after minor simplification. Two
249 * &&/|| expressions are considered equal if every operand in one expression
250 * equals some operand in the other (operands do not need to appear in the same
251 * order), recursively.
252 */
253static int expr_eq(struct expr *e1, struct expr *e2)
254{
255 int res, old_count;
256
257 if (e1->type != e2->type)
258 return 0;
259 switch (e1->type) {
260 case E_EQUAL:
261 case E_GEQ:
262 case E_GTH:
263 case E_LEQ:
264 case E_LTH:
265 case E_UNEQUAL:
266 return e1->left.sym == e2->left.sym && e1->right.sym == e2->right.sym;
267 case E_SYMBOL:
268 return e1->left.sym == e2->left.sym;
269 case E_NOT:
270 return expr_eq(e1->left.expr, e2->left.expr);
271 case E_AND:
272 case E_OR:
273 e1 = expr_copy(e1);
274 e2 = expr_copy(e2);
275 old_count = trans_count;
276 expr_eliminate_eq(&e1, &e2);
277 res = (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
278 e1->left.sym == e2->left.sym);
279 expr_free(e1);
280 expr_free(e2);
281 trans_count = old_count;
282 return res;
283 case E_LIST:
284 case E_RANGE:
285 case E_NONE:
286 /* panic */;
287 }
288
289 if (DEBUG_EXPR) {
290 expr_fprint(e1, stdout);
291 printf(" = ");
292 expr_fprint(e2, stdout);
293 printf(" ?\n");
294 }
295
296 return 0;
297}
298
299/*
300 * Recursively performs the following simplifications in-place (as well as the
301 * corresponding simplifications with swapped operands):
302 *
303 * expr && n -> n
304 * expr && y -> expr
305 * expr || n -> expr
306 * expr || y -> y
307 *
308 * Returns the optimized expression.
309 */
310static struct expr *expr_eliminate_yn(struct expr *e)
311{
312 struct expr *tmp;
313
314 if (e) switch (e->type) {
315 case E_AND:
316 e->left.expr = expr_eliminate_yn(e->left.expr);
317 e->right.expr = expr_eliminate_yn(e->right.expr);
318 if (e->left.expr->type == E_SYMBOL) {
319 if (e->left.expr->left.sym == &symbol_no) {
320 expr_free(e->left.expr);
321 expr_free(e->right.expr);
322 e->type = E_SYMBOL;
323 e->left.sym = &symbol_no;
324 e->right.expr = NULL;
325 return e;
326 } else if (e->left.expr->left.sym == &symbol_yes) {
327 free(e->left.expr);
328 tmp = e->right.expr;
329 *e = *(e->right.expr);
330 free(tmp);
331 return e;
332 }
333 }
334 if (e->right.expr->type == E_SYMBOL) {
335 if (e->right.expr->left.sym == &symbol_no) {
336 expr_free(e->left.expr);
337 expr_free(e->right.expr);
338 e->type = E_SYMBOL;
339 e->left.sym = &symbol_no;
340 e->right.expr = NULL;
341 return e;
342 } else if (e->right.expr->left.sym == &symbol_yes) {
343 free(e->right.expr);
344 tmp = e->left.expr;
345 *e = *(e->left.expr);
346 free(tmp);
347 return e;
348 }
349 }
350 break;
351 case E_OR:
352 e->left.expr = expr_eliminate_yn(e->left.expr);
353 e->right.expr = expr_eliminate_yn(e->right.expr);
354 if (e->left.expr->type == E_SYMBOL) {
355 if (e->left.expr->left.sym == &symbol_no) {
356 free(e->left.expr);
357 tmp = e->right.expr;
358 *e = *(e->right.expr);
359 free(tmp);
360 return e;
361 } else if (e->left.expr->left.sym == &symbol_yes) {
362 expr_free(e->left.expr);
363 expr_free(e->right.expr);
364 e->type = E_SYMBOL;
365 e->left.sym = &symbol_yes;
366 e->right.expr = NULL;
367 return e;
368 }
369 }
370 if (e->right.expr->type == E_SYMBOL) {
371 if (e->right.expr->left.sym == &symbol_no) {
372 free(e->right.expr);
373 tmp = e->left.expr;
374 *e = *(e->left.expr);
375 free(tmp);
376 return e;
377 } else if (e->right.expr->left.sym == &symbol_yes) {
378 expr_free(e->left.expr);
379 expr_free(e->right.expr);
380 e->type = E_SYMBOL;
381 e->left.sym = &symbol_yes;
382 e->right.expr = NULL;
383 return e;
384 }
385 }
386 break;
387 default:
388 ;
389 }
390 return e;
391}
392
393/*
394 * bool FOO!=n => FOO
395 */
396struct expr *expr_trans_bool(struct expr *e)
397{
398 if (!e)
399 return NULL;
400 switch (e->type) {
401 case E_AND:
402 case E_OR:
403 case E_NOT:
404 e->left.expr = expr_trans_bool(e->left.expr);
405 e->right.expr = expr_trans_bool(e->right.expr);
406 break;
407 case E_UNEQUAL:
408 // FOO!=n -> FOO
409 if (e->left.sym->type == S_TRISTATE) {
410 if (e->right.sym == &symbol_no) {
411 e->type = E_SYMBOL;
412 e->right.sym = NULL;
413 }
414 }
415 break;
416 default:
417 ;
418 }
419 return e;
420}
421
422/*
423 * e1 || e2 -> ?
424 */
425static struct expr *expr_join_or(struct expr *e1, struct expr *e2)
426{
427 struct expr *tmp;
428 struct symbol *sym1, *sym2;
429
430 if (expr_eq(e1, e2))
431 return expr_copy(e1);
432 if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
433 return NULL;
434 if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
435 return NULL;
436 if (e1->type == E_NOT) {
437 tmp = e1->left.expr;
438 if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
439 return NULL;
440 sym1 = tmp->left.sym;
441 } else
442 sym1 = e1->left.sym;
443 if (e2->type == E_NOT) {
444 if (e2->left.expr->type != E_SYMBOL)
445 return NULL;
446 sym2 = e2->left.expr->left.sym;
447 } else
448 sym2 = e2->left.sym;
449 if (sym1 != sym2)
450 return NULL;
451 if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
452 return NULL;
453 if (sym1->type == S_TRISTATE) {
454 if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
455 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
456 (e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes))) {
457 // (a='y') || (a='m') -> (a!='n')
458 return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_no);
459 }
460 if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
461 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
462 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes))) {
463 // (a='y') || (a='n') -> (a!='m')
464 return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_mod);
465 }
466 if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
467 ((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
468 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod))) {
469 // (a='m') || (a='n') -> (a!='y')
470 return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_yes);
471 }
472 }
473 if (sym1->type == S_BOOLEAN && sym1 == sym2) {
474 if ((e1->type == E_NOT && e1->left.expr->type == E_SYMBOL && e2->type == E_SYMBOL) ||
475 (e2->type == E_NOT && e2->left.expr->type == E_SYMBOL && e1->type == E_SYMBOL))
476 return expr_alloc_symbol(&symbol_yes);
477 }
478
479 if (DEBUG_EXPR) {
480 printf("optimize (");
481 expr_fprint(e1, stdout);
482 printf(") || (");
483 expr_fprint(e2, stdout);
484 printf(")?\n");
485 }
486 return NULL;
487}
488
489static struct expr *expr_join_and(struct expr *e1, struct expr *e2)
490{
491 struct expr *tmp;
492 struct symbol *sym1, *sym2;
493
494 if (expr_eq(e1, e2))
495 return expr_copy(e1);
496 if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
497 return NULL;
498 if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
499 return NULL;
500 if (e1->type == E_NOT) {
501 tmp = e1->left.expr;
502 if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
503 return NULL;
504 sym1 = tmp->left.sym;
505 } else
506 sym1 = e1->left.sym;
507 if (e2->type == E_NOT) {
508 if (e2->left.expr->type != E_SYMBOL)
509 return NULL;
510 sym2 = e2->left.expr->left.sym;
511 } else
512 sym2 = e2->left.sym;
513 if (sym1 != sym2)
514 return NULL;
515 if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
516 return NULL;
517
518 if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_yes) ||
519 (e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_yes))
520 // (a) && (a='y') -> (a='y')
521 return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
522
523 if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_no) ||
524 (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_no))
525 // (a) && (a!='n') -> (a)
526 return expr_alloc_symbol(sym1);
527
528 if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_mod) ||
529 (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_mod))
530 // (a) && (a!='m') -> (a='y')
531 return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
532
533 if (sym1->type == S_TRISTATE) {
534 if (e1->type == E_EQUAL && e2->type == E_UNEQUAL) {
535 // (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
536 sym2 = e1->right.sym;
537 if ((e2->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
538 return sym2 != e2->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
539 : expr_alloc_symbol(&symbol_no);
540 }
541 if (e1->type == E_UNEQUAL && e2->type == E_EQUAL) {
542 // (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
543 sym2 = e2->right.sym;
544 if ((e1->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
545 return sym2 != e1->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
546 : expr_alloc_symbol(&symbol_no);
547 }
548 if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
549 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
550 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes)))
551 // (a!='y') && (a!='n') -> (a='m')
552 return expr_alloc_comp(E_EQUAL, sym1, &symbol_mod);
553
554 if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
555 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
556 (e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes)))
557 // (a!='y') && (a!='m') -> (a='n')
558 return expr_alloc_comp(E_EQUAL, sym1, &symbol_no);
559
560 if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
561 ((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
562 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod)))
563 // (a!='m') && (a!='n') -> (a='m')
564 return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
565
566 if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_mod) ||
567 (e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_mod) ||
568 (e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_yes) ||
569 (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_yes))
570 return NULL;
571 }
572
573 if (DEBUG_EXPR) {
574 printf("optimize (");
575 expr_fprint(e1, stdout);
576 printf(") && (");
577 expr_fprint(e2, stdout);
578 printf(")?\n");
579 }
580 return NULL;
581}
582
583/*
584 * expr_eliminate_dups() helper.
585 *
586 * Walks the two expression trees given in 'ep1' and 'ep2'. Any node that does
587 * not have type 'type' (E_OR/E_AND) is considered a leaf, and is compared
588 * against all other leaves to look for simplifications.
589 */
590static void expr_eliminate_dups1(enum expr_type type, struct expr **ep1, struct expr **ep2)
591{
592#define e1 (*ep1)
593#define e2 (*ep2)
594 struct expr *tmp;
595
596 /* Recurse down to leaves */
597
598 if (e1->type == type) {
599 expr_eliminate_dups1(type, &e1->left.expr, &e2);
600 expr_eliminate_dups1(type, &e1->right.expr, &e2);
601 return;
602 }
603 if (e2->type == type) {
604 expr_eliminate_dups1(type, &e1, &e2->left.expr);
605 expr_eliminate_dups1(type, &e1, &e2->right.expr);
606 return;
607 }
608
609 /* e1 and e2 are leaves. Compare and process them. */
610
611 if (e1 == e2)
612 return;
613
614 switch (e1->type) {
615 case E_OR: case E_AND:
616 expr_eliminate_dups1(e1->type, &e1, &e1);
617 default:
618 ;
619 }
620
621 switch (type) {
622 case E_OR:
623 tmp = expr_join_or(e1, e2);
624 if (tmp) {
625 expr_free(e1); expr_free(e2);
626 e1 = expr_alloc_symbol(&symbol_no);
627 e2 = tmp;
628 trans_count++;
629 }
630 break;
631 case E_AND:
632 tmp = expr_join_and(e1, e2);
633 if (tmp) {
634 expr_free(e1); expr_free(e2);
635 e1 = expr_alloc_symbol(&symbol_yes);
636 e2 = tmp;
637 trans_count++;
638 }
639 break;
640 default:
641 ;
642 }
643#undef e1
644#undef e2
645}
646
647/*
648 * Rewrites 'e' in-place to remove ("join") duplicate and other redundant
649 * operands.
650 *
651 * Example simplifications:
652 *
653 * A || B || A -> A || B
654 * A && B && A=y -> A=y && B
655 *
656 * Returns the deduplicated expression.
657 */
658struct expr *expr_eliminate_dups(struct expr *e)
659{
660 int oldcount;
661 if (!e)
662 return e;
663
664 oldcount = trans_count;
665 while (1) {
666 trans_count = 0;
667 switch (e->type) {
668 case E_OR: case E_AND:
669 expr_eliminate_dups1(e->type, &e, &e);
670 default:
671 ;
672 }
673 if (!trans_count)
674 /* No simplifications done in this pass. We're done */
675 break;
676 e = expr_eliminate_yn(e);
677 }
678 trans_count = oldcount;
679 return e;
680}
681
682/*
683 * Performs various simplifications involving logical operators and
684 * comparisons.
685 *
686 * Allocates and returns a new expression.
687 */
688struct expr *expr_transform(struct expr *e)
689{
690 struct expr *tmp;
691
692 if (!e)
693 return NULL;
694 switch (e->type) {
695 case E_EQUAL:
696 case E_GEQ:
697 case E_GTH:
698 case E_LEQ:
699 case E_LTH:
700 case E_UNEQUAL:
701 case E_SYMBOL:
702 case E_LIST:
703 break;
704 default:
705 e->left.expr = expr_transform(e->left.expr);
706 e->right.expr = expr_transform(e->right.expr);
707 }
708
709 switch (e->type) {
710 case E_EQUAL:
711 if (e->left.sym->type != S_BOOLEAN)
712 break;
713 if (e->right.sym == &symbol_no) {
714 e->type = E_NOT;
715 e->left.expr = expr_alloc_symbol(e->left.sym);
716 e->right.sym = NULL;
717 break;
718 }
719 if (e->right.sym == &symbol_mod) {
720 printf("boolean symbol %s tested for 'm'? test forced to 'n'\n", e->left.sym->name);
721 e->type = E_SYMBOL;
722 e->left.sym = &symbol_no;
723 e->right.sym = NULL;
724 break;
725 }
726 if (e->right.sym == &symbol_yes) {
727 e->type = E_SYMBOL;
728 e->right.sym = NULL;
729 break;
730 }
731 break;
732 case E_UNEQUAL:
733 if (e->left.sym->type != S_BOOLEAN)
734 break;
735 if (e->right.sym == &symbol_no) {
736 e->type = E_SYMBOL;
737 e->right.sym = NULL;
738 break;
739 }
740 if (e->right.sym == &symbol_mod) {
741 printf("boolean symbol %s tested for 'm'? test forced to 'y'\n", e->left.sym->name);
742 e->type = E_SYMBOL;
743 e->left.sym = &symbol_yes;
744 e->right.sym = NULL;
745 break;
746 }
747 if (e->right.sym == &symbol_yes) {
748 e->type = E_NOT;
749 e->left.expr = expr_alloc_symbol(e->left.sym);
750 e->right.sym = NULL;
751 break;
752 }
753 break;
754 case E_NOT:
755 switch (e->left.expr->type) {
756 case E_NOT:
757 // !!a -> a
758 tmp = e->left.expr->left.expr;
759 free(e->left.expr);
760 free(e);
761 e = tmp;
762 e = expr_transform(e);
763 break;
764 case E_EQUAL:
765 case E_UNEQUAL:
766 // !a='x' -> a!='x'
767 tmp = e->left.expr;
768 free(e);
769 e = tmp;
770 e->type = e->type == E_EQUAL ? E_UNEQUAL : E_EQUAL;
771 break;
772 case E_LEQ:
773 case E_GEQ:
774 // !a<='x' -> a>'x'
775 tmp = e->left.expr;
776 free(e);
777 e = tmp;
778 e->type = e->type == E_LEQ ? E_GTH : E_LTH;
779 break;
780 case E_LTH:
781 case E_GTH:
782 // !a<'x' -> a>='x'
783 tmp = e->left.expr;
784 free(e);
785 e = tmp;
786 e->type = e->type == E_LTH ? E_GEQ : E_LEQ;
787 break;
788 case E_OR:
789 // !(a || b) -> !a && !b
790 tmp = e->left.expr;
791 e->type = E_AND;
792 e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
793 tmp->type = E_NOT;
794 tmp->right.expr = NULL;
795 e = expr_transform(e);
796 break;
797 case E_AND:
798 // !(a && b) -> !a || !b
799 tmp = e->left.expr;
800 e->type = E_OR;
801 e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
802 tmp->type = E_NOT;
803 tmp->right.expr = NULL;
804 e = expr_transform(e);
805 break;
806 case E_SYMBOL:
807 if (e->left.expr->left.sym == &symbol_yes) {
808 // !'y' -> 'n'
809 tmp = e->left.expr;
810 free(e);
811 e = tmp;
812 e->type = E_SYMBOL;
813 e->left.sym = &symbol_no;
814 break;
815 }
816 if (e->left.expr->left.sym == &symbol_mod) {
817 // !'m' -> 'm'
818 tmp = e->left.expr;
819 free(e);
820 e = tmp;
821 e->type = E_SYMBOL;
822 e->left.sym = &symbol_mod;
823 break;
824 }
825 if (e->left.expr->left.sym == &symbol_no) {
826 // !'n' -> 'y'
827 tmp = e->left.expr;
828 free(e);
829 e = tmp;
830 e->type = E_SYMBOL;
831 e->left.sym = &symbol_yes;
832 break;
833 }
834 break;
835 default:
836 ;
837 }
838 break;
839 default:
840 ;
841 }
842 return e;
843}
844
845int expr_contains_symbol(struct expr *dep, struct symbol *sym)
846{
847 if (!dep)
848 return 0;
849
850 switch (dep->type) {
851 case E_AND:
852 case E_OR:
853 return expr_contains_symbol(dep->left.expr, sym) ||
854 expr_contains_symbol(dep->right.expr, sym);
855 case E_SYMBOL:
856 return dep->left.sym == sym;
857 case E_EQUAL:
858 case E_GEQ:
859 case E_GTH:
860 case E_LEQ:
861 case E_LTH:
862 case E_UNEQUAL:
863 return dep->left.sym == sym ||
864 dep->right.sym == sym;
865 case E_NOT:
866 return expr_contains_symbol(dep->left.expr, sym);
867 default:
868 ;
869 }
870 return 0;
871}
872
873bool expr_depends_symbol(struct expr *dep, struct symbol *sym)
874{
875 if (!dep)
876 return false;
877
878 switch (dep->type) {
879 case E_AND:
880 return expr_depends_symbol(dep->left.expr, sym) ||
881 expr_depends_symbol(dep->right.expr, sym);
882 case E_SYMBOL:
883 return dep->left.sym == sym;
884 case E_EQUAL:
885 if (dep->left.sym == sym) {
886 if (dep->right.sym == &symbol_yes || dep->right.sym == &symbol_mod)
887 return true;
888 }
889 break;
890 case E_UNEQUAL:
891 if (dep->left.sym == sym) {
892 if (dep->right.sym == &symbol_no)
893 return true;
894 }
895 break;
896 default:
897 ;
898 }
899 return false;
900}
901
902/*
903 * Inserts explicit comparisons of type 'type' to symbol 'sym' into the
904 * expression 'e'.
905 *
906 * Examples transformations for type == E_UNEQUAL, sym == &symbol_no:
907 *
908 * A -> A!=n
909 * !A -> A=n
910 * A && B -> !(A=n || B=n)
911 * A || B -> !(A=n && B=n)
912 * A && (B || C) -> !(A=n || (B=n && C=n))
913 *
914 * Allocates and returns a new expression.
915 */
916struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym)
917{
918 struct expr *e1, *e2;
919
920 if (!e) {
921 e = expr_alloc_symbol(sym);
922 if (type == E_UNEQUAL)
923 e = expr_alloc_one(E_NOT, e);
924 return e;
925 }
926 switch (e->type) {
927 case E_AND:
928 e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
929 e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
930 if (sym == &symbol_yes)
931 e = expr_alloc_two(E_AND, e1, e2);
932 if (sym == &symbol_no)
933 e = expr_alloc_two(E_OR, e1, e2);
934 if (type == E_UNEQUAL)
935 e = expr_alloc_one(E_NOT, e);
936 return e;
937 case E_OR:
938 e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
939 e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
940 if (sym == &symbol_yes)
941 e = expr_alloc_two(E_OR, e1, e2);
942 if (sym == &symbol_no)
943 e = expr_alloc_two(E_AND, e1, e2);
944 if (type == E_UNEQUAL)
945 e = expr_alloc_one(E_NOT, e);
946 return e;
947 case E_NOT:
948 return expr_trans_compare(e->left.expr, type == E_EQUAL ? E_UNEQUAL : E_EQUAL, sym);
949 case E_UNEQUAL:
950 case E_LTH:
951 case E_LEQ:
952 case E_GTH:
953 case E_GEQ:
954 case E_EQUAL:
955 if (type == E_EQUAL) {
956 if (sym == &symbol_yes)
957 return expr_copy(e);
958 if (sym == &symbol_mod)
959 return expr_alloc_symbol(&symbol_no);
960 if (sym == &symbol_no)
961 return expr_alloc_one(E_NOT, expr_copy(e));
962 } else {
963 if (sym == &symbol_yes)
964 return expr_alloc_one(E_NOT, expr_copy(e));
965 if (sym == &symbol_mod)
966 return expr_alloc_symbol(&symbol_yes);
967 if (sym == &symbol_no)
968 return expr_copy(e);
969 }
970 break;
971 case E_SYMBOL:
972 return expr_alloc_comp(type, e->left.sym, sym);
973 case E_LIST:
974 case E_RANGE:
975 case E_NONE:
976 /* panic */;
977 }
978 return NULL;
979}
980
981enum string_value_kind {
982 k_string,
983 k_signed,
984 k_unsigned,
985};
986
987union string_value {
988 unsigned long long u;
989 signed long long s;
990};
991
992static enum string_value_kind expr_parse_string(const char *str,
993 enum symbol_type type,
994 union string_value *val)
995{
996 char *tail;
997 enum string_value_kind kind;
998
999 errno = 0;
1000 switch (type) {
1001 case S_BOOLEAN:
1002 case S_TRISTATE:
1003 val->s = !strcmp(str, "n") ? 0 :
1004 !strcmp(str, "m") ? 1 :
1005 !strcmp(str, "y") ? 2 : -1;
1006 return k_signed;
1007 case S_INT:
1008 val->s = strtoll(str, &tail, 10);
1009 kind = k_signed;
1010 break;
1011 case S_HEX:
1012 val->u = strtoull(str, &tail, 16);
1013 kind = k_unsigned;
1014 break;
1015 default:
1016 val->s = strtoll(str, &tail, 0);
1017 kind = k_signed;
1018 break;
1019 }
1020 return !errno && !*tail && tail > str && isxdigit(tail[-1])
1021 ? kind : k_string;
1022}
1023
1024tristate expr_calc_value(struct expr *e)
1025{
1026 tristate val1, val2;
1027 const char *str1, *str2;
1028 enum string_value_kind k1 = k_string, k2 = k_string;
1029 union string_value lval = {}, rval = {};
1030 int res;
1031
1032 if (!e)
1033 return yes;
1034
1035 switch (e->type) {
1036 case E_SYMBOL:
1037 sym_calc_value(e->left.sym);
1038 return e->left.sym->curr.tri;
1039 case E_AND:
1040 val1 = expr_calc_value(e->left.expr);
1041 val2 = expr_calc_value(e->right.expr);
1042 return EXPR_AND(val1, val2);
1043 case E_OR:
1044 val1 = expr_calc_value(e->left.expr);
1045 val2 = expr_calc_value(e->right.expr);
1046 return EXPR_OR(val1, val2);
1047 case E_NOT:
1048 val1 = expr_calc_value(e->left.expr);
1049 return EXPR_NOT(val1);
1050 case E_EQUAL:
1051 case E_GEQ:
1052 case E_GTH:
1053 case E_LEQ:
1054 case E_LTH:
1055 case E_UNEQUAL:
1056 break;
1057 default:
1058 printf("expr_calc_value: %d?\n", e->type);
1059 return no;
1060 }
1061
1062 sym_calc_value(e->left.sym);
1063 sym_calc_value(e->right.sym);
1064 str1 = sym_get_string_value(e->left.sym);
1065 str2 = sym_get_string_value(e->right.sym);
1066
1067 if (e->left.sym->type != S_STRING || e->right.sym->type != S_STRING) {
1068 k1 = expr_parse_string(str1, e->left.sym->type, &lval);
1069 k2 = expr_parse_string(str2, e->right.sym->type, &rval);
1070 }
1071
1072 if (k1 == k_string || k2 == k_string)
1073 res = strcmp(str1, str2);
1074 else if (k1 == k_unsigned || k2 == k_unsigned)
1075 res = (lval.u > rval.u) - (lval.u < rval.u);
1076 else /* if (k1 == k_signed && k2 == k_signed) */
1077 res = (lval.s > rval.s) - (lval.s < rval.s);
1078
1079 switch(e->type) {
1080 case E_EQUAL:
1081 return res ? no : yes;
1082 case E_GEQ:
1083 return res >= 0 ? yes : no;
1084 case E_GTH:
1085 return res > 0 ? yes : no;
1086 case E_LEQ:
1087 return res <= 0 ? yes : no;
1088 case E_LTH:
1089 return res < 0 ? yes : no;
1090 case E_UNEQUAL:
1091 return res ? yes : no;
1092 default:
1093 printf("expr_calc_value: relation %d?\n", e->type);
1094 return no;
1095 }
1096}
1097
1098static int expr_compare_type(enum expr_type t1, enum expr_type t2)
1099{
1100 if (t1 == t2)
1101 return 0;
1102 switch (t1) {
1103 case E_LEQ:
1104 case E_LTH:
1105 case E_GEQ:
1106 case E_GTH:
1107 if (t2 == E_EQUAL || t2 == E_UNEQUAL)
1108 return 1;
1109 case E_EQUAL:
1110 case E_UNEQUAL:
1111 if (t2 == E_NOT)
1112 return 1;
1113 case E_NOT:
1114 if (t2 == E_AND)
1115 return 1;
1116 case E_AND:
1117 if (t2 == E_OR)
1118 return 1;
1119 case E_OR:
1120 if (t2 == E_LIST)
1121 return 1;
1122 case E_LIST:
1123 if (t2 == 0)
1124 return 1;
1125 default:
1126 return -1;
1127 }
1128 printf("[%dgt%d?]", t1, t2);
1129 return 0;
1130}
1131
1132void expr_print(struct expr *e,
1133 void (*fn)(void *, struct symbol *, const char *),
1134 void *data, int prevtoken)
1135{
1136 if (!e) {
1137 fn(data, NULL, "y");
1138 return;
1139 }
1140
1141 if (expr_compare_type(prevtoken, e->type) > 0)
1142 fn(data, NULL, "(");
1143 switch (e->type) {
1144 case E_SYMBOL:
1145 if (e->left.sym->name)
1146 fn(data, e->left.sym, e->left.sym->name);
1147 else
1148 fn(data, NULL, "<choice>");
1149 break;
1150 case E_NOT:
1151 fn(data, NULL, "!");
1152 expr_print(e->left.expr, fn, data, E_NOT);
1153 break;
1154 case E_EQUAL:
1155 if (e->left.sym->name)
1156 fn(data, e->left.sym, e->left.sym->name);
1157 else
1158 fn(data, NULL, "<choice>");
1159 fn(data, NULL, "=");
1160 fn(data, e->right.sym, e->right.sym->name);
1161 break;
1162 case E_LEQ:
1163 case E_LTH:
1164 if (e->left.sym->name)
1165 fn(data, e->left.sym, e->left.sym->name);
1166 else
1167 fn(data, NULL, "<choice>");
1168 fn(data, NULL, e->type == E_LEQ ? "<=" : "<");
1169 fn(data, e->right.sym, e->right.sym->name);
1170 break;
1171 case E_GEQ:
1172 case E_GTH:
1173 if (e->left.sym->name)
1174 fn(data, e->left.sym, e->left.sym->name);
1175 else
1176 fn(data, NULL, "<choice>");
1177 fn(data, NULL, e->type == E_GEQ ? ">=" : ">");
1178 fn(data, e->right.sym, e->right.sym->name);
1179 break;
1180 case E_UNEQUAL:
1181 if (e->left.sym->name)
1182 fn(data, e->left.sym, e->left.sym->name);
1183 else
1184 fn(data, NULL, "<choice>");
1185 fn(data, NULL, "!=");
1186 fn(data, e->right.sym, e->right.sym->name);
1187 break;
1188 case E_OR:
1189 expr_print(e->left.expr, fn, data, E_OR);
1190 fn(data, NULL, " || ");
1191 expr_print(e->right.expr, fn, data, E_OR);
1192 break;
1193 case E_AND:
1194 expr_print(e->left.expr, fn, data, E_AND);
1195 fn(data, NULL, " && ");
1196 expr_print(e->right.expr, fn, data, E_AND);
1197 break;
1198 case E_LIST:
1199 fn(data, e->right.sym, e->right.sym->name);
1200 if (e->left.expr) {
1201 fn(data, NULL, " ^ ");
1202 expr_print(e->left.expr, fn, data, E_LIST);
1203 }
1204 break;
1205 case E_RANGE:
1206 fn(data, NULL, "[");
1207 fn(data, e->left.sym, e->left.sym->name);
1208 fn(data, NULL, " ");
1209 fn(data, e->right.sym, e->right.sym->name);
1210 fn(data, NULL, "]");
1211 break;
1212 default:
1213 {
1214 char buf[32];
1215 sprintf(buf, "<unknown type %d>", e->type);
1216 fn(data, NULL, buf);
1217 break;
1218 }
1219 }
1220 if (expr_compare_type(prevtoken, e->type) > 0)
1221 fn(data, NULL, ")");
1222}
1223
1224static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
1225{
1226 xfwrite(str, strlen(str), 1, data);
1227}
1228
1229void expr_fprint(struct expr *e, FILE *out)
1230{
1231 expr_print(e, expr_print_file_helper, out, E_NONE);
1232}
1233
1234static void expr_print_gstr_helper(void *data, struct symbol *sym, const char *str)
1235{
1236 struct gstr *gs = (struct gstr*)data;
1237 const char *sym_str = NULL;
1238
1239 if (sym)
1240 sym_str = sym_get_string_value(sym);
1241
1242 if (gs->max_width) {
1243 unsigned extra_length = strlen(str);
1244 const char *last_cr = strrchr(gs->s, '\n');
1245 unsigned last_line_length;
1246
1247 if (sym_str)
1248 extra_length += 4 + strlen(sym_str);
1249
1250 if (!last_cr)
1251 last_cr = gs->s;
1252
1253 last_line_length = strlen(gs->s) - (last_cr - gs->s);
1254
1255 if ((last_line_length + extra_length) > gs->max_width)
1256 str_append(gs, "\\\n");
1257 }
1258
1259 str_append(gs, str);
1260 if (sym && sym->type != S_UNKNOWN)
1261 str_printf(gs, " [=%s]", sym_str);
1262}
1263
1264void expr_gstr_print(struct expr *e, struct gstr *gs)
1265{
1266 expr_print(e, expr_print_gstr_helper, gs, E_NONE);
1267}
1268
1269/*
1270 * Transform the top level "||" tokens into newlines and prepend each
1271 * line with a minus. This makes expressions much easier to read.
1272 * Suitable for reverse dependency expressions.
1273 */
1274static void expr_print_revdep(struct expr *e,
1275 void (*fn)(void *, struct symbol *, const char *),
1276 void *data, tristate pr_type, const char **title)
1277{
1278 if (e->type == E_OR) {
1279 expr_print_revdep(e->left.expr, fn, data, pr_type, title);
1280 expr_print_revdep(e->right.expr, fn, data, pr_type, title);
1281 } else if (expr_calc_value(e) == pr_type) {
1282 if (*title) {
1283 fn(data, NULL, *title);
1284 *title = NULL;
1285 }
1286
1287 fn(data, NULL, " - ");
1288 expr_print(e, fn, data, E_NONE);
1289 fn(data, NULL, "\n");
1290 }
1291}
1292
1293void expr_gstr_print_revdep(struct expr *e, struct gstr *gs,
1294 tristate pr_type, const char *title)
1295{
1296 expr_print_revdep(e, expr_print_gstr_helper, gs, pr_type, &title);
1297}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
4 */
5
6#include <ctype.h>
7#include <errno.h>
8#include <stdio.h>
9#include <stdlib.h>
10#include <string.h>
11
12#include <hash.h>
13#include <xalloc.h>
14#include "internal.h"
15#include "lkc.h"
16
17#define DEBUG_EXPR 0
18
19HASHTABLE_DEFINE(expr_hashtable, EXPR_HASHSIZE);
20
21static struct expr *expr_eliminate_yn(struct expr *e);
22
23/**
24 * expr_lookup - return the expression with the given type and sub-nodes
25 * This looks up an expression with the specified type and sub-nodes. If such
26 * an expression is found in the hash table, it is returned. Otherwise, a new
27 * expression node is allocated and added to the hash table.
28 * @type: expression type
29 * @l: left node
30 * @r: right node
31 * return: expression
32 */
33static struct expr *expr_lookup(enum expr_type type, void *l, void *r)
34{
35 struct expr *e;
36 int hash;
37
38 hash = hash_32((unsigned int)type ^ hash_ptr(l) ^ hash_ptr(r));
39
40 hash_for_each_possible(expr_hashtable, e, node, hash) {
41 if (e->type == type && e->left._initdata == l &&
42 e->right._initdata == r)
43 return e;
44 }
45
46 e = xmalloc(sizeof(*e));
47 e->type = type;
48 e->left._initdata = l;
49 e->right._initdata = r;
50 e->val_is_valid = false;
51
52 hash_add(expr_hashtable, &e->node, hash);
53
54 return e;
55}
56
57struct expr *expr_alloc_symbol(struct symbol *sym)
58{
59 return expr_lookup(E_SYMBOL, sym, NULL);
60}
61
62struct expr *expr_alloc_one(enum expr_type type, struct expr *ce)
63{
64 return expr_lookup(type, ce, NULL);
65}
66
67struct expr *expr_alloc_two(enum expr_type type, struct expr *e1, struct expr *e2)
68{
69 return expr_lookup(type, e1, e2);
70}
71
72struct expr *expr_alloc_comp(enum expr_type type, struct symbol *s1, struct symbol *s2)
73{
74 return expr_lookup(type, s1, s2);
75}
76
77struct expr *expr_alloc_and(struct expr *e1, struct expr *e2)
78{
79 if (!e1)
80 return e2;
81 return e2 ? expr_alloc_two(E_AND, e1, e2) : e1;
82}
83
84struct expr *expr_alloc_or(struct expr *e1, struct expr *e2)
85{
86 if (!e1)
87 return e2;
88 return e2 ? expr_alloc_two(E_OR, e1, e2) : e1;
89}
90
91static int trans_count;
92
93/*
94 * expr_eliminate_eq() helper.
95 *
96 * Walks the two expression trees given in 'ep1' and 'ep2'. Any node that does
97 * not have type 'type' (E_OR/E_AND) is considered a leaf, and is compared
98 * against all other leaves. Two equal leaves are both replaced with either 'y'
99 * or 'n' as appropriate for 'type', to be eliminated later.
100 */
101static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct expr **ep2)
102{
103 struct expr *l, *r;
104
105 /* Recurse down to leaves */
106
107 if ((*ep1)->type == type) {
108 l = (*ep1)->left.expr;
109 r = (*ep1)->right.expr;
110 __expr_eliminate_eq(type, &l, ep2);
111 __expr_eliminate_eq(type, &r, ep2);
112 *ep1 = expr_alloc_two(type, l, r);
113 return;
114 }
115 if ((*ep2)->type == type) {
116 l = (*ep2)->left.expr;
117 r = (*ep2)->right.expr;
118 __expr_eliminate_eq(type, ep1, &l);
119 __expr_eliminate_eq(type, ep1, &r);
120 *ep2 = expr_alloc_two(type, l, r);
121 return;
122 }
123
124 /* *ep1 and *ep2 are leaves. Compare them. */
125
126 if ((*ep1)->type == E_SYMBOL && (*ep2)->type == E_SYMBOL &&
127 (*ep1)->left.sym == (*ep2)->left.sym &&
128 ((*ep1)->left.sym == &symbol_yes || (*ep1)->left.sym == &symbol_no))
129 return;
130 if (!expr_eq(*ep1, *ep2))
131 return;
132
133 /* *ep1 and *ep2 are equal leaves. Prepare them for elimination. */
134
135 trans_count++;
136 switch (type) {
137 case E_OR:
138 *ep1 = expr_alloc_symbol(&symbol_no);
139 *ep2 = expr_alloc_symbol(&symbol_no);
140 break;
141 case E_AND:
142 *ep1 = expr_alloc_symbol(&symbol_yes);
143 *ep2 = expr_alloc_symbol(&symbol_yes);
144 break;
145 default:
146 ;
147 }
148}
149
150/*
151 * Rewrites the expressions 'ep1' and 'ep2' to remove operands common to both.
152 * Example reductions:
153 *
154 * ep1: A && B -> ep1: y
155 * ep2: A && B && C -> ep2: C
156 *
157 * ep1: A || B -> ep1: n
158 * ep2: A || B || C -> ep2: C
159 *
160 * ep1: A && (B && FOO) -> ep1: FOO
161 * ep2: (BAR && B) && A -> ep2: BAR
162 *
163 * ep1: A && (B || C) -> ep1: y
164 * ep2: (C || B) && A -> ep2: y
165 *
166 * Comparisons are done between all operands at the same "level" of && or ||.
167 * For example, in the expression 'e1 && (e2 || e3) && (e4 || e5)', the
168 * following operands will be compared:
169 *
170 * - 'e1', 'e2 || e3', and 'e4 || e5', against each other
171 * - e2 against e3
172 * - e4 against e5
173 *
174 * Parentheses are irrelevant within a single level. 'e1 && (e2 && e3)' and
175 * '(e1 && e2) && e3' are both a single level.
176 *
177 * See __expr_eliminate_eq() as well.
178 */
179void expr_eliminate_eq(struct expr **ep1, struct expr **ep2)
180{
181 if (!*ep1 || !*ep2)
182 return;
183 switch ((*ep1)->type) {
184 case E_OR:
185 case E_AND:
186 __expr_eliminate_eq((*ep1)->type, ep1, ep2);
187 default:
188 ;
189 }
190 if ((*ep1)->type != (*ep2)->type) switch ((*ep2)->type) {
191 case E_OR:
192 case E_AND:
193 __expr_eliminate_eq((*ep2)->type, ep1, ep2);
194 default:
195 ;
196 }
197 *ep1 = expr_eliminate_yn(*ep1);
198 *ep2 = expr_eliminate_yn(*ep2);
199}
200
201/*
202 * Returns true if 'e1' and 'e2' are equal, after minor simplification. Two
203 * &&/|| expressions are considered equal if every operand in one expression
204 * equals some operand in the other (operands do not need to appear in the same
205 * order), recursively.
206 */
207bool expr_eq(struct expr *e1, struct expr *e2)
208{
209 int old_count;
210 bool res;
211
212 /*
213 * A NULL expr is taken to be yes, but there's also a different way to
214 * represent yes. expr_is_yes() checks for either representation.
215 */
216 if (!e1 || !e2)
217 return expr_is_yes(e1) && expr_is_yes(e2);
218
219 if (e1->type != e2->type)
220 return false;
221 switch (e1->type) {
222 case E_EQUAL:
223 case E_GEQ:
224 case E_GTH:
225 case E_LEQ:
226 case E_LTH:
227 case E_UNEQUAL:
228 return e1->left.sym == e2->left.sym && e1->right.sym == e2->right.sym;
229 case E_SYMBOL:
230 return e1->left.sym == e2->left.sym;
231 case E_NOT:
232 return expr_eq(e1->left.expr, e2->left.expr);
233 case E_AND:
234 case E_OR:
235 old_count = trans_count;
236 expr_eliminate_eq(&e1, &e2);
237 res = (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
238 e1->left.sym == e2->left.sym);
239 trans_count = old_count;
240 return res;
241 case E_RANGE:
242 case E_NONE:
243 /* panic */;
244 }
245
246 if (DEBUG_EXPR) {
247 expr_fprint(e1, stdout);
248 printf(" = ");
249 expr_fprint(e2, stdout);
250 printf(" ?\n");
251 }
252
253 return false;
254}
255
256/*
257 * Recursively performs the following simplifications (as well as the
258 * corresponding simplifications with swapped operands):
259 *
260 * expr && n -> n
261 * expr && y -> expr
262 * expr || n -> expr
263 * expr || y -> y
264 *
265 * Returns the optimized expression.
266 */
267static struct expr *expr_eliminate_yn(struct expr *e)
268{
269 struct expr *l, *r;
270
271 if (e) switch (e->type) {
272 case E_AND:
273 l = expr_eliminate_yn(e->left.expr);
274 r = expr_eliminate_yn(e->right.expr);
275 if (l->type == E_SYMBOL) {
276 if (l->left.sym == &symbol_no)
277 return l;
278 else if (l->left.sym == &symbol_yes)
279 return r;
280 }
281 if (r->type == E_SYMBOL) {
282 if (r->left.sym == &symbol_no)
283 return r;
284 else if (r->left.sym == &symbol_yes)
285 return l;
286 }
287 break;
288 case E_OR:
289 l = expr_eliminate_yn(e->left.expr);
290 r = expr_eliminate_yn(e->right.expr);
291 if (l->type == E_SYMBOL) {
292 if (l->left.sym == &symbol_no)
293 return r;
294 else if (l->left.sym == &symbol_yes)
295 return l;
296 }
297 if (r->type == E_SYMBOL) {
298 if (r->left.sym == &symbol_no)
299 return l;
300 else if (r->left.sym == &symbol_yes)
301 return r;
302 }
303 break;
304 default:
305 ;
306 }
307 return e;
308}
309
310/*
311 * e1 || e2 -> ?
312 */
313static struct expr *expr_join_or(struct expr *e1, struct expr *e2)
314{
315 struct expr *tmp;
316 struct symbol *sym1, *sym2;
317
318 if (expr_eq(e1, e2))
319 return e1;
320 if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
321 return NULL;
322 if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
323 return NULL;
324 if (e1->type == E_NOT) {
325 tmp = e1->left.expr;
326 if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
327 return NULL;
328 sym1 = tmp->left.sym;
329 } else
330 sym1 = e1->left.sym;
331 if (e2->type == E_NOT) {
332 if (e2->left.expr->type != E_SYMBOL)
333 return NULL;
334 sym2 = e2->left.expr->left.sym;
335 } else
336 sym2 = e2->left.sym;
337 if (sym1 != sym2)
338 return NULL;
339 if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
340 return NULL;
341 if (sym1->type == S_TRISTATE) {
342 if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
343 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
344 (e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes))) {
345 // (a='y') || (a='m') -> (a!='n')
346 return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_no);
347 }
348 if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
349 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
350 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes))) {
351 // (a='y') || (a='n') -> (a!='m')
352 return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_mod);
353 }
354 if (e1->type == E_EQUAL && e2->type == E_EQUAL &&
355 ((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
356 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod))) {
357 // (a='m') || (a='n') -> (a!='y')
358 return expr_alloc_comp(E_UNEQUAL, sym1, &symbol_yes);
359 }
360 }
361 if (sym1->type == S_BOOLEAN) {
362 // a || !a -> y
363 if ((e1->type == E_NOT && e1->left.expr->type == E_SYMBOL && e2->type == E_SYMBOL) ||
364 (e2->type == E_NOT && e2->left.expr->type == E_SYMBOL && e1->type == E_SYMBOL))
365 return expr_alloc_symbol(&symbol_yes);
366 }
367
368 if (DEBUG_EXPR) {
369 printf("optimize (");
370 expr_fprint(e1, stdout);
371 printf(") || (");
372 expr_fprint(e2, stdout);
373 printf(")?\n");
374 }
375 return NULL;
376}
377
378static struct expr *expr_join_and(struct expr *e1, struct expr *e2)
379{
380 struct expr *tmp;
381 struct symbol *sym1, *sym2;
382
383 if (expr_eq(e1, e2))
384 return e1;
385 if (e1->type != E_EQUAL && e1->type != E_UNEQUAL && e1->type != E_SYMBOL && e1->type != E_NOT)
386 return NULL;
387 if (e2->type != E_EQUAL && e2->type != E_UNEQUAL && e2->type != E_SYMBOL && e2->type != E_NOT)
388 return NULL;
389 if (e1->type == E_NOT) {
390 tmp = e1->left.expr;
391 if (tmp->type != E_EQUAL && tmp->type != E_UNEQUAL && tmp->type != E_SYMBOL)
392 return NULL;
393 sym1 = tmp->left.sym;
394 } else
395 sym1 = e1->left.sym;
396 if (e2->type == E_NOT) {
397 if (e2->left.expr->type != E_SYMBOL)
398 return NULL;
399 sym2 = e2->left.expr->left.sym;
400 } else
401 sym2 = e2->left.sym;
402 if (sym1 != sym2)
403 return NULL;
404 if (sym1->type != S_BOOLEAN && sym1->type != S_TRISTATE)
405 return NULL;
406
407 if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_yes) ||
408 (e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_yes))
409 // (a) && (a='y') -> (a='y')
410 return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
411
412 if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_no) ||
413 (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_no))
414 // (a) && (a!='n') -> (a)
415 return expr_alloc_symbol(sym1);
416
417 if ((e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_mod) ||
418 (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_mod))
419 // (a) && (a!='m') -> (a='y')
420 return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
421
422 if (sym1->type == S_TRISTATE) {
423 if (e1->type == E_EQUAL && e2->type == E_UNEQUAL) {
424 // (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
425 sym2 = e1->right.sym;
426 if ((e2->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
427 return sym2 != e2->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
428 : expr_alloc_symbol(&symbol_no);
429 }
430 if (e1->type == E_UNEQUAL && e2->type == E_EQUAL) {
431 // (a='b') && (a!='c') -> 'b'='c' ? 'n' : a='b'
432 sym2 = e2->right.sym;
433 if ((e1->right.sym->flags & SYMBOL_CONST) && (sym2->flags & SYMBOL_CONST))
434 return sym2 != e1->right.sym ? expr_alloc_comp(E_EQUAL, sym1, sym2)
435 : expr_alloc_symbol(&symbol_no);
436 }
437 if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
438 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_no) ||
439 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_yes)))
440 // (a!='y') && (a!='n') -> (a='m')
441 return expr_alloc_comp(E_EQUAL, sym1, &symbol_mod);
442
443 if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
444 ((e1->right.sym == &symbol_yes && e2->right.sym == &symbol_mod) ||
445 (e1->right.sym == &symbol_mod && e2->right.sym == &symbol_yes)))
446 // (a!='y') && (a!='m') -> (a='n')
447 return expr_alloc_comp(E_EQUAL, sym1, &symbol_no);
448
449 if (e1->type == E_UNEQUAL && e2->type == E_UNEQUAL &&
450 ((e1->right.sym == &symbol_mod && e2->right.sym == &symbol_no) ||
451 (e1->right.sym == &symbol_no && e2->right.sym == &symbol_mod)))
452 // (a!='m') && (a!='n') -> (a='m')
453 return expr_alloc_comp(E_EQUAL, sym1, &symbol_yes);
454
455 if ((e1->type == E_SYMBOL && e2->type == E_EQUAL && e2->right.sym == &symbol_mod) ||
456 (e2->type == E_SYMBOL && e1->type == E_EQUAL && e1->right.sym == &symbol_mod) ||
457 (e1->type == E_SYMBOL && e2->type == E_UNEQUAL && e2->right.sym == &symbol_yes) ||
458 (e2->type == E_SYMBOL && e1->type == E_UNEQUAL && e1->right.sym == &symbol_yes))
459 return NULL;
460 }
461
462 if (DEBUG_EXPR) {
463 printf("optimize (");
464 expr_fprint(e1, stdout);
465 printf(") && (");
466 expr_fprint(e2, stdout);
467 printf(")?\n");
468 }
469 return NULL;
470}
471
472/*
473 * expr_eliminate_dups() helper.
474 *
475 * Walks the two expression trees given in 'ep1' and 'ep2'. Any node that does
476 * not have type 'type' (E_OR/E_AND) is considered a leaf, and is compared
477 * against all other leaves to look for simplifications.
478 */
479static void expr_eliminate_dups1(enum expr_type type, struct expr **ep1, struct expr **ep2)
480{
481 struct expr *tmp, *l, *r;
482
483 /* Recurse down to leaves */
484
485 if ((*ep1)->type == type) {
486 l = (*ep1)->left.expr;
487 r = (*ep1)->right.expr;
488 expr_eliminate_dups1(type, &l, ep2);
489 expr_eliminate_dups1(type, &r, ep2);
490 *ep1 = expr_alloc_two(type, l, r);
491 return;
492 }
493 if ((*ep2)->type == type) {
494 l = (*ep2)->left.expr;
495 r = (*ep2)->right.expr;
496 expr_eliminate_dups1(type, ep1, &l);
497 expr_eliminate_dups1(type, ep1, &r);
498 *ep2 = expr_alloc_two(type, l, r);
499 return;
500 }
501
502 /* *ep1 and *ep2 are leaves. Compare and process them. */
503
504 switch (type) {
505 case E_OR:
506 tmp = expr_join_or(*ep1, *ep2);
507 if (tmp) {
508 *ep1 = expr_alloc_symbol(&symbol_no);
509 *ep2 = tmp;
510 trans_count++;
511 }
512 break;
513 case E_AND:
514 tmp = expr_join_and(*ep1, *ep2);
515 if (tmp) {
516 *ep1 = expr_alloc_symbol(&symbol_yes);
517 *ep2 = tmp;
518 trans_count++;
519 }
520 break;
521 default:
522 ;
523 }
524}
525
526/*
527 * Rewrites 'e' in-place to remove ("join") duplicate and other redundant
528 * operands.
529 *
530 * Example simplifications:
531 *
532 * A || B || A -> A || B
533 * A && B && A=y -> A=y && B
534 *
535 * Returns the deduplicated expression.
536 */
537struct expr *expr_eliminate_dups(struct expr *e)
538{
539 int oldcount;
540 if (!e)
541 return e;
542
543 oldcount = trans_count;
544 do {
545 struct expr *l, *r;
546
547 trans_count = 0;
548 switch (e->type) {
549 case E_OR: case E_AND:
550 l = expr_eliminate_dups(e->left.expr);
551 r = expr_eliminate_dups(e->right.expr);
552 expr_eliminate_dups1(e->type, &l, &r);
553 e = expr_alloc_two(e->type, l, r);
554 default:
555 ;
556 }
557 e = expr_eliminate_yn(e);
558 } while (trans_count); /* repeat until we get no more simplifications */
559 trans_count = oldcount;
560 return e;
561}
562
563/*
564 * Performs various simplifications involving logical operators and
565 * comparisons.
566 *
567 * For bool type:
568 * A=n -> !A
569 * A=m -> n
570 * A=y -> A
571 * A!=n -> A
572 * A!=m -> y
573 * A!=y -> !A
574 *
575 * For any type:
576 * !!A -> A
577 * !(A=B) -> A!=B
578 * !(A!=B) -> A=B
579 * !(A<=B) -> A>B
580 * !(A>=B) -> A<B
581 * !(A<B) -> A>=B
582 * !(A>B) -> A<=B
583 * !(A || B) -> !A && !B
584 * !(A && B) -> !A || !B
585 *
586 * For constant:
587 * !y -> n
588 * !m -> m
589 * !n -> y
590 *
591 * Allocates and returns a new expression.
592 */
593struct expr *expr_transform(struct expr *e)
594{
595 if (!e)
596 return NULL;
597 switch (e->type) {
598 case E_EQUAL:
599 case E_GEQ:
600 case E_GTH:
601 case E_LEQ:
602 case E_LTH:
603 case E_UNEQUAL:
604 case E_SYMBOL:
605 break;
606 default:
607 e = expr_alloc_two(e->type,
608 expr_transform(e->left.expr),
609 expr_transform(e->right.expr));
610 }
611
612 switch (e->type) {
613 case E_EQUAL:
614 if (e->left.sym->type != S_BOOLEAN)
615 break;
616 if (e->right.sym == &symbol_no) {
617 // A=n -> !A
618 e = expr_alloc_one(E_NOT, expr_alloc_symbol(e->left.sym));
619 break;
620 }
621 if (e->right.sym == &symbol_mod) {
622 // A=m -> n
623 printf("boolean symbol %s tested for 'm'? test forced to 'n'\n", e->left.sym->name);
624 e = expr_alloc_symbol(&symbol_no);
625 break;
626 }
627 if (e->right.sym == &symbol_yes) {
628 // A=y -> A
629 e = expr_alloc_symbol(e->left.sym);
630 break;
631 }
632 break;
633 case E_UNEQUAL:
634 if (e->left.sym->type != S_BOOLEAN)
635 break;
636 if (e->right.sym == &symbol_no) {
637 // A!=n -> A
638 e = expr_alloc_symbol(e->left.sym);
639 break;
640 }
641 if (e->right.sym == &symbol_mod) {
642 // A!=m -> y
643 printf("boolean symbol %s tested for 'm'? test forced to 'y'\n", e->left.sym->name);
644 e = expr_alloc_symbol(&symbol_yes);
645 break;
646 }
647 if (e->right.sym == &symbol_yes) {
648 // A!=y -> !A
649 e = expr_alloc_one(E_NOT, e->left.expr);
650 break;
651 }
652 break;
653 case E_NOT:
654 switch (e->left.expr->type) {
655 case E_NOT:
656 // !!A -> A
657 e = e->left.expr->left.expr;
658 break;
659 case E_EQUAL:
660 case E_UNEQUAL:
661 // !(A=B) -> A!=B
662 e = expr_alloc_comp(e->left.expr->type == E_EQUAL ? E_UNEQUAL : E_EQUAL,
663 e->left.expr->left.sym,
664 e->left.expr->right.sym);
665 break;
666 case E_LEQ:
667 case E_GEQ:
668 // !(A<=B) -> A>B
669 e = expr_alloc_comp(e->left.expr->type == E_LEQ ? E_GTH : E_LTH,
670 e->left.expr->left.sym,
671 e->left.expr->right.sym);
672 break;
673 case E_LTH:
674 case E_GTH:
675 // !(A<B) -> A>=B
676 e = expr_alloc_comp(e->left.expr->type == E_LTH ? E_GEQ : E_LEQ,
677 e->left.expr->left.sym,
678 e->left.expr->right.sym);
679 break;
680 case E_OR:
681 // !(A || B) -> !A && !B
682 e = expr_alloc_and(expr_alloc_one(E_NOT, e->left.expr->left.expr),
683 expr_alloc_one(E_NOT, e->left.expr->right.expr));
684 e = expr_transform(e);
685 break;
686 case E_AND:
687 // !(A && B) -> !A || !B
688 e = expr_alloc_or(expr_alloc_one(E_NOT, e->left.expr->left.expr),
689 expr_alloc_one(E_NOT, e->left.expr->right.expr));
690 e = expr_transform(e);
691 break;
692 case E_SYMBOL:
693 if (e->left.expr->left.sym == &symbol_yes)
694 // !'y' -> 'n'
695 e = expr_alloc_symbol(&symbol_no);
696 else if (e->left.expr->left.sym == &symbol_mod)
697 // !'m' -> 'm'
698 e = expr_alloc_symbol(&symbol_mod);
699 else if (e->left.expr->left.sym == &symbol_no)
700 // !'n' -> 'y'
701 e = expr_alloc_symbol(&symbol_yes);
702 break;
703 default:
704 ;
705 }
706 break;
707 default:
708 ;
709 }
710 return e;
711}
712
713bool expr_contains_symbol(struct expr *dep, struct symbol *sym)
714{
715 if (!dep)
716 return false;
717
718 switch (dep->type) {
719 case E_AND:
720 case E_OR:
721 return expr_contains_symbol(dep->left.expr, sym) ||
722 expr_contains_symbol(dep->right.expr, sym);
723 case E_SYMBOL:
724 return dep->left.sym == sym;
725 case E_EQUAL:
726 case E_GEQ:
727 case E_GTH:
728 case E_LEQ:
729 case E_LTH:
730 case E_UNEQUAL:
731 return dep->left.sym == sym ||
732 dep->right.sym == sym;
733 case E_NOT:
734 return expr_contains_symbol(dep->left.expr, sym);
735 default:
736 ;
737 }
738 return false;
739}
740
741bool expr_depends_symbol(struct expr *dep, struct symbol *sym)
742{
743 if (!dep)
744 return false;
745
746 switch (dep->type) {
747 case E_AND:
748 return expr_depends_symbol(dep->left.expr, sym) ||
749 expr_depends_symbol(dep->right.expr, sym);
750 case E_SYMBOL:
751 return dep->left.sym == sym;
752 case E_EQUAL:
753 if (dep->left.sym == sym) {
754 if (dep->right.sym == &symbol_yes || dep->right.sym == &symbol_mod)
755 return true;
756 }
757 break;
758 case E_UNEQUAL:
759 if (dep->left.sym == sym) {
760 if (dep->right.sym == &symbol_no)
761 return true;
762 }
763 break;
764 default:
765 ;
766 }
767 return false;
768}
769
770/*
771 * Inserts explicit comparisons of type 'type' to symbol 'sym' into the
772 * expression 'e'.
773 *
774 * Examples transformations for type == E_UNEQUAL, sym == &symbol_no:
775 *
776 * A -> A!=n
777 * !A -> A=n
778 * A && B -> !(A=n || B=n)
779 * A || B -> !(A=n && B=n)
780 * A && (B || C) -> !(A=n || (B=n && C=n))
781 *
782 * Allocates and returns a new expression.
783 */
784struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym)
785{
786 struct expr *e1, *e2;
787
788 if (!e) {
789 e = expr_alloc_symbol(sym);
790 if (type == E_UNEQUAL)
791 e = expr_alloc_one(E_NOT, e);
792 return e;
793 }
794 switch (e->type) {
795 case E_AND:
796 e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
797 e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
798 if (sym == &symbol_yes)
799 e = expr_alloc_two(E_AND, e1, e2);
800 if (sym == &symbol_no)
801 e = expr_alloc_two(E_OR, e1, e2);
802 if (type == E_UNEQUAL)
803 e = expr_alloc_one(E_NOT, e);
804 return e;
805 case E_OR:
806 e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
807 e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
808 if (sym == &symbol_yes)
809 e = expr_alloc_two(E_OR, e1, e2);
810 if (sym == &symbol_no)
811 e = expr_alloc_two(E_AND, e1, e2);
812 if (type == E_UNEQUAL)
813 e = expr_alloc_one(E_NOT, e);
814 return e;
815 case E_NOT:
816 return expr_trans_compare(e->left.expr, type == E_EQUAL ? E_UNEQUAL : E_EQUAL, sym);
817 case E_UNEQUAL:
818 case E_LTH:
819 case E_LEQ:
820 case E_GTH:
821 case E_GEQ:
822 case E_EQUAL:
823 if (type == E_EQUAL) {
824 if (sym == &symbol_yes)
825 return e;
826 if (sym == &symbol_mod)
827 return expr_alloc_symbol(&symbol_no);
828 if (sym == &symbol_no)
829 return expr_alloc_one(E_NOT, e);
830 } else {
831 if (sym == &symbol_yes)
832 return expr_alloc_one(E_NOT, e);
833 if (sym == &symbol_mod)
834 return expr_alloc_symbol(&symbol_yes);
835 if (sym == &symbol_no)
836 return e;
837 }
838 break;
839 case E_SYMBOL:
840 return expr_alloc_comp(type, e->left.sym, sym);
841 case E_RANGE:
842 case E_NONE:
843 /* panic */;
844 }
845 return NULL;
846}
847
848enum string_value_kind {
849 k_string,
850 k_signed,
851 k_unsigned,
852};
853
854union string_value {
855 unsigned long long u;
856 signed long long s;
857};
858
859static enum string_value_kind expr_parse_string(const char *str,
860 enum symbol_type type,
861 union string_value *val)
862{
863 char *tail;
864 enum string_value_kind kind;
865
866 errno = 0;
867 switch (type) {
868 case S_BOOLEAN:
869 case S_TRISTATE:
870 val->s = !strcmp(str, "n") ? 0 :
871 !strcmp(str, "m") ? 1 :
872 !strcmp(str, "y") ? 2 : -1;
873 return k_signed;
874 case S_INT:
875 val->s = strtoll(str, &tail, 10);
876 kind = k_signed;
877 break;
878 case S_HEX:
879 val->u = strtoull(str, &tail, 16);
880 kind = k_unsigned;
881 break;
882 default:
883 val->s = strtoll(str, &tail, 0);
884 kind = k_signed;
885 break;
886 }
887 return !errno && !*tail && tail > str && isxdigit(tail[-1])
888 ? kind : k_string;
889}
890
891static tristate __expr_calc_value(struct expr *e)
892{
893 tristate val1, val2;
894 const char *str1, *str2;
895 enum string_value_kind k1 = k_string, k2 = k_string;
896 union string_value lval = {}, rval = {};
897 int res;
898
899 switch (e->type) {
900 case E_SYMBOL:
901 sym_calc_value(e->left.sym);
902 return e->left.sym->curr.tri;
903 case E_AND:
904 val1 = expr_calc_value(e->left.expr);
905 val2 = expr_calc_value(e->right.expr);
906 return EXPR_AND(val1, val2);
907 case E_OR:
908 val1 = expr_calc_value(e->left.expr);
909 val2 = expr_calc_value(e->right.expr);
910 return EXPR_OR(val1, val2);
911 case E_NOT:
912 val1 = expr_calc_value(e->left.expr);
913 return EXPR_NOT(val1);
914 case E_EQUAL:
915 case E_GEQ:
916 case E_GTH:
917 case E_LEQ:
918 case E_LTH:
919 case E_UNEQUAL:
920 break;
921 default:
922 printf("expr_calc_value: %d?\n", e->type);
923 return no;
924 }
925
926 sym_calc_value(e->left.sym);
927 sym_calc_value(e->right.sym);
928 str1 = sym_get_string_value(e->left.sym);
929 str2 = sym_get_string_value(e->right.sym);
930
931 if (e->left.sym->type != S_STRING || e->right.sym->type != S_STRING) {
932 k1 = expr_parse_string(str1, e->left.sym->type, &lval);
933 k2 = expr_parse_string(str2, e->right.sym->type, &rval);
934 }
935
936 if (k1 == k_string || k2 == k_string)
937 res = strcmp(str1, str2);
938 else if (k1 == k_unsigned || k2 == k_unsigned)
939 res = (lval.u > rval.u) - (lval.u < rval.u);
940 else /* if (k1 == k_signed && k2 == k_signed) */
941 res = (lval.s > rval.s) - (lval.s < rval.s);
942
943 switch(e->type) {
944 case E_EQUAL:
945 return res ? no : yes;
946 case E_GEQ:
947 return res >= 0 ? yes : no;
948 case E_GTH:
949 return res > 0 ? yes : no;
950 case E_LEQ:
951 return res <= 0 ? yes : no;
952 case E_LTH:
953 return res < 0 ? yes : no;
954 case E_UNEQUAL:
955 return res ? yes : no;
956 default:
957 printf("expr_calc_value: relation %d?\n", e->type);
958 return no;
959 }
960}
961
962/**
963 * expr_calc_value - return the tristate value of the given expression
964 * @e: expression
965 * return: tristate value of the expression
966 */
967tristate expr_calc_value(struct expr *e)
968{
969 if (!e)
970 return yes;
971
972 if (!e->val_is_valid) {
973 e->val = __expr_calc_value(e);
974 e->val_is_valid = true;
975 }
976
977 return e->val;
978}
979
980/**
981 * expr_invalidate_all - invalidate all cached expression values
982 */
983void expr_invalidate_all(void)
984{
985 struct expr *e;
986
987 hash_for_each(expr_hashtable, e, node)
988 e->val_is_valid = false;
989}
990
991static int expr_compare_type(enum expr_type t1, enum expr_type t2)
992{
993 if (t1 == t2)
994 return 0;
995 switch (t1) {
996 case E_LEQ:
997 case E_LTH:
998 case E_GEQ:
999 case E_GTH:
1000 if (t2 == E_EQUAL || t2 == E_UNEQUAL)
1001 return 1;
1002 /* fallthrough */
1003 case E_EQUAL:
1004 case E_UNEQUAL:
1005 if (t2 == E_NOT)
1006 return 1;
1007 /* fallthrough */
1008 case E_NOT:
1009 if (t2 == E_AND)
1010 return 1;
1011 /* fallthrough */
1012 case E_AND:
1013 if (t2 == E_OR)
1014 return 1;
1015 /* fallthrough */
1016 default:
1017 break;
1018 }
1019 return 0;
1020}
1021
1022void expr_print(const struct expr *e,
1023 void (*fn)(void *, struct symbol *, const char *),
1024 void *data, int prevtoken)
1025{
1026 if (!e) {
1027 fn(data, NULL, "y");
1028 return;
1029 }
1030
1031 if (expr_compare_type(prevtoken, e->type) > 0)
1032 fn(data, NULL, "(");
1033 switch (e->type) {
1034 case E_SYMBOL:
1035 if (e->left.sym->name)
1036 fn(data, e->left.sym, e->left.sym->name);
1037 else
1038 fn(data, NULL, "<choice>");
1039 break;
1040 case E_NOT:
1041 fn(data, NULL, "!");
1042 expr_print(e->left.expr, fn, data, E_NOT);
1043 break;
1044 case E_EQUAL:
1045 if (e->left.sym->name)
1046 fn(data, e->left.sym, e->left.sym->name);
1047 else
1048 fn(data, NULL, "<choice>");
1049 fn(data, NULL, "=");
1050 fn(data, e->right.sym, e->right.sym->name);
1051 break;
1052 case E_LEQ:
1053 case E_LTH:
1054 if (e->left.sym->name)
1055 fn(data, e->left.sym, e->left.sym->name);
1056 else
1057 fn(data, NULL, "<choice>");
1058 fn(data, NULL, e->type == E_LEQ ? "<=" : "<");
1059 fn(data, e->right.sym, e->right.sym->name);
1060 break;
1061 case E_GEQ:
1062 case E_GTH:
1063 if (e->left.sym->name)
1064 fn(data, e->left.sym, e->left.sym->name);
1065 else
1066 fn(data, NULL, "<choice>");
1067 fn(data, NULL, e->type == E_GEQ ? ">=" : ">");
1068 fn(data, e->right.sym, e->right.sym->name);
1069 break;
1070 case E_UNEQUAL:
1071 if (e->left.sym->name)
1072 fn(data, e->left.sym, e->left.sym->name);
1073 else
1074 fn(data, NULL, "<choice>");
1075 fn(data, NULL, "!=");
1076 fn(data, e->right.sym, e->right.sym->name);
1077 break;
1078 case E_OR:
1079 expr_print(e->left.expr, fn, data, E_OR);
1080 fn(data, NULL, " || ");
1081 expr_print(e->right.expr, fn, data, E_OR);
1082 break;
1083 case E_AND:
1084 expr_print(e->left.expr, fn, data, E_AND);
1085 fn(data, NULL, " && ");
1086 expr_print(e->right.expr, fn, data, E_AND);
1087 break;
1088 case E_RANGE:
1089 fn(data, NULL, "[");
1090 fn(data, e->left.sym, e->left.sym->name);
1091 fn(data, NULL, " ");
1092 fn(data, e->right.sym, e->right.sym->name);
1093 fn(data, NULL, "]");
1094 break;
1095 default:
1096 {
1097 char buf[32];
1098 sprintf(buf, "<unknown type %d>", e->type);
1099 fn(data, NULL, buf);
1100 break;
1101 }
1102 }
1103 if (expr_compare_type(prevtoken, e->type) > 0)
1104 fn(data, NULL, ")");
1105}
1106
1107static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
1108{
1109 xfwrite(str, strlen(str), 1, data);
1110}
1111
1112void expr_fprint(struct expr *e, FILE *out)
1113{
1114 expr_print(e, expr_print_file_helper, out, E_NONE);
1115}
1116
1117static void expr_print_gstr_helper(void *data, struct symbol *sym, const char *str)
1118{
1119 struct gstr *gs = (struct gstr*)data;
1120 const char *sym_str = NULL;
1121
1122 if (sym)
1123 sym_str = sym_get_string_value(sym);
1124
1125 if (gs->max_width) {
1126 unsigned extra_length = strlen(str);
1127 const char *last_cr = strrchr(gs->s, '\n');
1128 unsigned last_line_length;
1129
1130 if (sym_str)
1131 extra_length += 4 + strlen(sym_str);
1132
1133 if (!last_cr)
1134 last_cr = gs->s;
1135
1136 last_line_length = strlen(gs->s) - (last_cr - gs->s);
1137
1138 if ((last_line_length + extra_length) > gs->max_width)
1139 str_append(gs, "\\\n");
1140 }
1141
1142 str_append(gs, str);
1143 if (sym && sym->type != S_UNKNOWN)
1144 str_printf(gs, " [=%s]", sym_str);
1145}
1146
1147void expr_gstr_print(const struct expr *e, struct gstr *gs)
1148{
1149 expr_print(e, expr_print_gstr_helper, gs, E_NONE);
1150}
1151
1152/*
1153 * Transform the top level "||" tokens into newlines and prepend each
1154 * line with a minus. This makes expressions much easier to read.
1155 * Suitable for reverse dependency expressions.
1156 */
1157static void expr_print_revdep(struct expr *e,
1158 void (*fn)(void *, struct symbol *, const char *),
1159 void *data, tristate pr_type, const char **title)
1160{
1161 if (e->type == E_OR) {
1162 expr_print_revdep(e->left.expr, fn, data, pr_type, title);
1163 expr_print_revdep(e->right.expr, fn, data, pr_type, title);
1164 } else if (expr_calc_value(e) == pr_type) {
1165 if (*title) {
1166 fn(data, NULL, *title);
1167 *title = NULL;
1168 }
1169
1170 fn(data, NULL, " - ");
1171 expr_print(e, fn, data, E_NONE);
1172 fn(data, NULL, "\n");
1173 }
1174}
1175
1176void expr_gstr_print_revdep(struct expr *e, struct gstr *gs,
1177 tristate pr_type, const char *title)
1178{
1179 expr_print_revdep(e, expr_print_gstr_helper, gs, pr_type, &title);
1180}