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Merge tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...
[linux-2.6-block.git] / scripts / kconfig / expr.c
CommitLineData
0c874100 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT		 2/*
3 * Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
1da177e4
LT		 4 */
5
558e78e3
MY		 6#include <ctype.h>
7#include <errno.h>
1da177e4
LT		 8#include <stdio.h>
9#include <stdlib.h>
10#include <string.h>
11
1da177e4
LT		 12#include "lkc.h"
13
14#define DEBUG_EXPR 0
15
ad8d40cd
MM		 16static int expr_eq(struct expr *e1, struct expr *e2);
17static struct expr *expr_eliminate_yn(struct expr *e);
ad8d40cd 18
1da177e4
LT		 19struct expr *expr_alloc_symbol(struct symbol *sym)
20{
177acf78 21 struct expr *e = xcalloc(1, sizeof(*e));
1da177e4
LT		 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{
177acf78 29 struct expr *e = xcalloc(1, sizeof(*e));
1da177e4
LT		 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{
177acf78 37 struct expr *e = xcalloc(1, sizeof(*e));
1da177e4
LT		 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{
177acf78 46 struct expr *e = xcalloc(1, sizeof(*e));
1da177e4
LT		 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
17742dc7 67struct expr *expr_copy(const struct expr *org)
1da177e4
LT		 68{
69 struct expr *e;
70
71 if (!org)
72 return NULL;
73
177acf78 74 e = xmalloc(sizeof(*org));
1da177e4
LT		 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:
31847b67
JB		 84 case E_GEQ:
85 case E_GTH:
86 case E_LEQ:
87 case E_LTH:
1da177e4
LT		 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:
7a962923 94 case E_LIST:
1da177e4
LT		 95 e->left.expr = expr_copy(org->left.expr);
96 e->right.expr = expr_copy(org->right.expr);
97 break;
98 default:
9e3e10c7 99 fprintf(stderr, "can't copy type %d\n", e->type);
1da177e4
LT		 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);
5b1374b3 118 break;
1da177e4 119 case E_EQUAL:
31847b67
JB		 120 case E_GEQ:
121 case E_GTH:
122 case E_LEQ:
123 case E_LTH:
1da177e4
LT		 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:
9e3e10c7 132 fprintf(stderr, "how to free type %d?\n", e->type);
1da177e4
LT		 133 break;
134 }
135 free(e);
136}
137
138static int trans_count;
139
140#define e1 (*ep1)
141#define e2 (*ep2)
142
0735f7e5
UM		 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 */
1da177e4
LT		 151static void __expr_eliminate_eq(enum expr_type type, struct expr **ep1, struct expr **ep2)
152{
0735f7e5
UM		 153 /* Recurse down to leaves */
154
1da177e4
LT		 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 }
0735f7e5
UM		 165
166 /* e1 and e2 are leaves. Compare them. */
167
1da177e4 168 if (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
c0e150ac
RZ		 169 e1->left.sym == e2->left.sym &&
170 (e1->left.sym == &symbol_yes || e1->left.sym == &symbol_no))
1da177e4
LT		 171 return;
172 if (!expr_eq(e1, e2))
173 return;
0735f7e5
UM		 174
175 /* e1 and e2 are equal leaves. Prepare them for elimination. */
176
1da177e4
LT		 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
0735f7e5
UM		 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 */
1da177e4
LT		 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
0735f7e5
UM		 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 */
ad8d40cd 253static int expr_eq(struct expr *e1, struct expr *e2)
1da177e4
LT		 254{
255 int res, old_count;
256
257 if (e1->type != e2->type)
258 return 0;
259 switch (e1->type) {
260 case E_EQUAL:
31847b67
JB		 261 case E_GEQ:
262 case E_GTH:
263 case E_LEQ:
264 case E_LTH:
1da177e4
LT		 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;
7a962923 283 case E_LIST:
1da177e4
LT		 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
0735f7e5
UM		 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 */
ad8d40cd 310static struct expr *expr_eliminate_yn(struct expr *e)
1da177e4
LT		 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 */
4356f489 425static struct expr *expr_join_or(struct expr *e1, struct expr *e2)
1da177e4
LT		 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
4356f489 489static struct expr *expr_join_and(struct expr *e1, struct expr *e2)
1da177e4
LT		 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
0735f7e5
UM		 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 */
1da177e4
LT		 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
0735f7e5
UM		 596 /* Recurse down to leaves */
597
1da177e4
LT		 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 }
0735f7e5
UM		 608
609 /* e1 and e2 are leaves. Compare and process them. */
610
1da177e4
LT		 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
0735f7e5
UM		 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 */
1da177e4
LT		 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);
1da177e4
LT		 670 default:
671 ;
672 }
673 if (!trans_count)
0735f7e5 674 /* No simplifications done in this pass. We're done */
1da177e4
LT		 675 break;
676 e = expr_eliminate_yn(e);
677 }
678 trans_count = oldcount;
679 return e;
680}
681
0735f7e5
UM		 682/*
683 * Performs various simplifications involving logical operators and
684 * comparisons.
685 *
686 * Allocates and returns a new expression.
687 */
1da177e4
LT		 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:
31847b67
JB		 696 case E_GEQ:
697 case E_GTH:
698 case E_LEQ:
699 case E_LTH:
1da177e4
LT		 700 case E_UNEQUAL:
701 case E_SYMBOL:
7a962923 702 case E_LIST:
1da177e4
LT		 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;
31847b67
JB		 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;
1da177e4
LT		 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:
31847b67
JB		 858 case E_GEQ:
859 case E_GTH:
860 case E_LEQ:
861 case E_LTH:
1da177e4
LT		 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
0735f7e5
UM		 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 */
1da177e4
LT		 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:
31847b67
JB		 950 case E_LTH:
951 case E_LEQ:
952 case E_GTH:
953 case E_GEQ:
1da177e4
LT		 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);
7a962923 973 case E_LIST:
1da177e4
LT		 974 case E_RANGE:
975 case E_NONE:
976 /* panic */;
977 }
978 return NULL;
979}
980
31847b67
JB		 981enum string_value_kind {
982 k_string,
983 k_signed,
984 k_unsigned,
31847b67
JB		 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:
9059a349
NP		 1003 val->s = !strcmp(str, "n") ? 0 :
1004 !strcmp(str, "m") ? 1 :
1005 !strcmp(str, "y") ? 2 : -1;
1006 return k_signed;
31847b67
JB		 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;
0cbe3ac4 1015 default:
31847b67
JB		 1016 val->s = strtoll(str, &tail, 0);
1017 kind = k_signed;
1018 break;
31847b67
JB		 1019 }
1020 return !errno && !*tail && tail > str && isxdigit(tail[-1])
1021 ? kind : k_string;
1022}
1023
1da177e4
LT		 1024tristate expr_calc_value(struct expr *e)
1025{
1026 tristate val1, val2;
1027 const char *str1, *str2;
31847b67
JB		 1028 enum string_value_kind k1 = k_string, k2 = k_string;
1029 union string_value lval = {}, rval = {};
1030 int res;
1da177e4
LT		 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);
d6ee3576 1042 return EXPR_AND(val1, val2);
1da177e4
LT		 1043 case E_OR:
1044 val1 = expr_calc_value(e->left.expr);
1045 val2 = expr_calc_value(e->right.expr);
d6ee3576 1046 return EXPR_OR(val1, val2);
1da177e4
LT		 1047 case E_NOT:
1048 val1 = expr_calc_value(e->left.expr);
d6ee3576 1049 return EXPR_NOT(val1);
1da177e4 1050 case E_EQUAL:
31847b67
JB		 1051 case E_GEQ:
1052 case E_GTH:
1053 case E_LEQ:
1054 case E_LTH:
1da177e4 1055 case E_UNEQUAL:
31847b67 1056 break;
1da177e4
LT		 1057 default:
1058 printf("expr_calc_value: %d?\n", e->type);
1059 return no;
1060 }
31847b67
JB		 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);
0cbe3ac4 1074 else if (k1 == k_unsigned || k2 == k_unsigned)
31847b67
JB		 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 }
1da177e4
LT		 1096}
1097
ad8d40cd 1098static int expr_compare_type(enum expr_type t1, enum expr_type t2)
1da177e4 1099{
1da177e4
LT		 1100 if (t1 == t2)
1101 return 0;
1102 switch (t1) {
31847b67
JB		 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;
1da177e4
LT		 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:
7a962923 1120 if (t2 == E_LIST)
1da177e4 1121 return 1;
7a962923 1122 case E_LIST:
1da177e4
LT		 1123 if (t2 == 0)
1124 return 1;
1125 default:
1126 return -1;
1127 }
1128 printf("[%dgt%d?]", t1, t2);
1129 return 0;
1da177e4
LT		 1130}
1131
9a47ceec
MY		 1132void expr_print(struct expr *e,
1133 void (*fn)(void *, struct symbol *, const char *),
1134 void *data, int prevtoken)
1da177e4
LT		 1135{
1136 if (!e) {
ab45d190 1137 fn(data, NULL, "y");
1da177e4
LT		 1138 return;
1139 }
1140
1141 if (expr_compare_type(prevtoken, e->type) > 0)
ab45d190 1142 fn(data, NULL, "(");
1da177e4
LT		 1143 switch (e->type) {
1144 case E_SYMBOL:
1145 if (e->left.sym->name)
ab45d190 1146 fn(data, e->left.sym, e->left.sym->name);
1da177e4 1147 else
ab45d190 1148 fn(data, NULL, "<choice>");
1da177e4
LT		 1149 break;
1150 case E_NOT:
ab45d190 1151 fn(data, NULL, "!");
1da177e4
LT		 1152 expr_print(e->left.expr, fn, data, E_NOT);
1153 break;
1154 case E_EQUAL:
f5eaa323
JB		 1155 if (e->left.sym->name)
1156 fn(data, e->left.sym, e->left.sym->name);
1157 else
1158 fn(data, NULL, "<choice>");
ab45d190
RZ		 1159 fn(data, NULL, "=");
1160 fn(data, e->right.sym, e->right.sym->name);
31847b67
JB		 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>");
f6aad261 1177 fn(data, NULL, e->type == E_GEQ ? ">=" : ">");
31847b67 1178 fn(data, e->right.sym, e->right.sym->name);
1da177e4
LT		 1179 break;
1180 case E_UNEQUAL:
f5eaa323
JB		 1181 if (e->left.sym->name)
1182 fn(data, e->left.sym, e->left.sym->name);
1183 else
1184 fn(data, NULL, "<choice>");
ab45d190
RZ		 1185 fn(data, NULL, "!=");
1186 fn(data, e->right.sym, e->right.sym->name);
1da177e4
LT		 1187 break;
1188 case E_OR:
9a47ceec
MY		 1189 expr_print(e->left.expr, fn, data, E_OR);
1190 fn(data, NULL, " || ");
1191 expr_print(e->right.expr, fn, data, E_OR);
1da177e4
LT		 1192 break;
1193 case E_AND:
1194 expr_print(e->left.expr, fn, data, E_AND);
ab45d190 1195 fn(data, NULL, " && ");
1da177e4
LT		 1196 expr_print(e->right.expr, fn, data, E_AND);
1197 break;
7a962923 1198 case E_LIST:
ab45d190 1199 fn(data, e->right.sym, e->right.sym->name);
1da177e4 1200 if (e->left.expr) {
ab45d190 1201 fn(data, NULL, " ^ ");
7a962923 1202 expr_print(e->left.expr, fn, data, E_LIST);
1da177e4
LT		 1203 }
1204 break;
1205 case E_RANGE:
ab45d190
RZ		 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, "]");
1da177e4
LT		 1211 break;
1212 default:
1213 {
1214 char buf[32];
1215 sprintf(buf, "<unknown type %d>", e->type);
ab45d190 1216 fn(data, NULL, buf);
1da177e4
LT		 1217 break;
1218 }
1219 }
1220 if (expr_compare_type(prevtoken, e->type) > 0)
ab45d190 1221 fn(data, NULL, ")");
1da177e4
LT		 1222}
1223
ab45d190 1224static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
1da177e4 1225{
bf5e327a 1226 xfwrite(str, strlen(str), 1, data);
1da177e4
LT		 1227}
1228
1229void expr_fprint(struct expr *e, FILE *out)
1230{
1231 expr_print(e, expr_print_file_helper, out, E_NONE);
1232}
1233
ab45d190 1234static void expr_print_gstr_helper(void *data, struct symbol *sym, const char *str)
1da177e4 1235{
da60fbbc
VB		 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);
70ed0747 1260 if (sym && sym->type != S_UNKNOWN)
da60fbbc 1261 str_printf(gs, " [=%s]", sym_str);
1da177e4
LT		 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}
1ccb2714
PV		 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 */
9a47ceec
MY		 1274static void expr_print_revdep(struct expr *e,
1275 void (*fn)(void *, struct symbol *, const char *),
d9119b59 1276 void *data, tristate pr_type, const char **title)
9a47ceec
MY		 1277{
1278 if (e->type == E_OR) {
d9119b59
ER		 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
9a47ceec
MY		 1287 fn(data, NULL, " - ");
1288 expr_print(e, fn, data, E_NONE);
1289 fn(data, NULL, "\n");
1290 }
1291}
1292
d9119b59
ER		 1293void expr_gstr_print_revdep(struct expr *e, struct gstr *gs,
1294 tristate pr_type, const char *title)
1ccb2714 1295{
d9119b59 1296 expr_print_revdep(e, expr_print_gstr_helper, gs, pr_type, &title);
1ccb2714 1297}
Linux 6.x block layer and io_uring tree(s)