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(type: E_SYMBOL, l: sym, NULL);
60}
61
62struct expr *expr_alloc_one(enum expr_type type, struct expr *ce)
63{
64 return expr_lookup(type, l: 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, l: e1, r: e2);
70}
71
72struct expr *expr_alloc_comp(enum expr_type type, struct symbol *s1, struct symbol *s2)
73{
74 return expr_lookup(type, l: s1, r: 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(type: 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(type: 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, ep1: &l, ep2);
111 __expr_eliminate_eq(type, ep1: &r, ep2);
112 *ep1 = expr_alloc_two(type, e1: l, e2: 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, ep2: &l);
119 __expr_eliminate_eq(type, ep1, ep2: &r);
120 *ep2 = expr_alloc_two(type, e1: l, e2: 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(e1: *ep1, e2: *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(sym: &symbol_no);
139 *ep2 = expr_alloc_symbol(sym: &symbol_no);
140 break;
141 case E_AND:
142 *ep1 = expr_alloc_symbol(sym: &symbol_yes);
143 *ep2 = expr_alloc_symbol(sym: &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(type: (*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(type: (*ep2)->type, ep1, ep2);
194 default:
195 ;
196 }
197 *ep1 = expr_eliminate_yn(e: *ep1);
198 *ep2 = expr_eliminate_yn(e: *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(e: e1) && expr_is_yes(e: 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: e1->left.expr, e2: e2->left.expr);
233 case E_AND:
234 case E_OR:
235 old_count = trans_count;
236 expr_eliminate_eq(ep1: &e1, ep2: &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(e: e1, stdout);
248 printf(format: " = ");
249 expr_fprint(e: e2, stdout);
250 printf(format: " ?\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: e->left.expr);
274 r = expr_eliminate_yn(e: 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: e->left.expr);
290 r = expr_eliminate_yn(e: 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(type: E_UNEQUAL, s1: sym1, s2: &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(type: E_UNEQUAL, s1: sym1, s2: &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(type: E_UNEQUAL, s1: sym1, s2: &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(sym: &symbol_yes);
366 }
367
368 if (DEBUG_EXPR) {
369 printf(format: "optimize (");
370 expr_fprint(e: e1, stdout);
371 printf(format: ") || (");
372 expr_fprint(e: e2, stdout);
373 printf(format: ")?\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(type: E_EQUAL, s1: sym1, s2: &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(sym: 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(type: E_EQUAL, s1: sym1, s2: &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(type: E_EQUAL, s1: sym1, s2: sym2)
428 : expr_alloc_symbol(sym: &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(type: E_EQUAL, s1: sym1, s2: sym2)
435 : expr_alloc_symbol(sym: &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(type: E_EQUAL, s1: sym1, s2: &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(type: E_EQUAL, s1: sym1, s2: &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(type: E_EQUAL, s1: sym1, s2: &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(format: "optimize (");
464 expr_fprint(e: e1, stdout);
465 printf(format: ") && (");
466 expr_fprint(e: e2, stdout);
467 printf(format: ")?\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, ep1: &l, ep2);
489 expr_eliminate_dups1(type, ep1: &r, ep2);
490 *ep1 = expr_alloc_two(type, e1: l, e2: 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, ep2: &l);
497 expr_eliminate_dups1(type, ep1, ep2: &r);
498 *ep2 = expr_alloc_two(type, e1: l, e2: 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(e1: *ep1, e2: *ep2);
507 if (tmp) {
508 *ep1 = expr_alloc_symbol(sym: &symbol_no);
509 *ep2 = tmp;
510 trans_count++;
511 }
512 break;
513 case E_AND:
514 tmp = expr_join_and(e1: *ep1, e2: *ep2);
515 if (tmp) {
516 *ep1 = expr_alloc_symbol(sym: &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: e->left.expr);
551 r = expr_eliminate_dups(e: e->right.expr);
552 expr_eliminate_dups1(type: e->type, ep1: &l, ep2: &r);
553 e = expr_alloc_two(type: e->type, e1: l, e2: 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(type: e->type,
608 e1: expr_transform(e: e->left.expr),
609 e2: expr_transform(e: 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(type: E_NOT, ce: expr_alloc_symbol(sym: e->left.sym));
619 break;
620 }
621 if (e->right.sym == &symbol_mod) {
622 // A=m -> n
623 printf(format: "boolean symbol %s tested for 'm'? test forced to 'n'\n", e->left.sym->name);
624 e = expr_alloc_symbol(sym: &symbol_no);
625 break;
626 }
627 if (e->right.sym == &symbol_yes) {
628 // A=y -> A
629 e = expr_alloc_symbol(sym: 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(sym: e->left.sym);
639 break;
640 }
641 if (e->right.sym == &symbol_mod) {
642 // A!=m -> y
643 printf(format: "boolean symbol %s tested for 'm'? test forced to 'y'\n", e->left.sym->name);
644 e = expr_alloc_symbol(sym: &symbol_yes);
645 break;
646 }
647 if (e->right.sym == &symbol_yes) {
648 // A!=y -> !A
649 e = expr_alloc_one(type: E_NOT, ce: 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(type: e->left.expr->type == E_EQUAL ? E_UNEQUAL : E_EQUAL,
663 s1: e->left.expr->left.sym,
664 s2: 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(type: e->left.expr->type == E_LEQ ? E_GTH : E_LTH,
670 s1: e->left.expr->left.sym,
671 s2: 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(type: e->left.expr->type == E_LTH ? E_GEQ : E_LEQ,
677 s1: e->left.expr->left.sym,
678 s2: e->left.expr->right.sym);
679 break;
680 case E_OR:
681 // !(A || B) -> !A && !B
682 e = expr_alloc_and(e1: expr_alloc_one(type: E_NOT, ce: e->left.expr->left.expr),
683 e2: expr_alloc_one(type: E_NOT, ce: 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(e1: expr_alloc_one(type: E_NOT, ce: e->left.expr->left.expr),
689 e2: expr_alloc_one(type: E_NOT, ce: 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(sym: &symbol_no);
696 else if (e->left.expr->left.sym == &symbol_mod)
697 // !'m' -> 'm'
698 e = expr_alloc_symbol(sym: &symbol_mod);
699 else if (e->left.expr->left.sym == &symbol_no)
700 // !'n' -> 'y'
701 e = expr_alloc_symbol(sym: &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: dep->left.expr, sym) ||
722 expr_contains_symbol(dep: 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: 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: dep->left.expr, sym) ||
749 expr_depends_symbol(dep: 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(type: E_NOT, ce: e);
792 return e;
793 }
794 switch (e->type) {
795 case E_AND:
796 e1 = expr_trans_compare(e: e->left.expr, type: E_EQUAL, sym);
797 e2 = expr_trans_compare(e: e->right.expr, type: E_EQUAL, sym);
798 if (sym == &symbol_yes)
799 e = expr_alloc_two(type: E_AND, e1, e2);
800 if (sym == &symbol_no)
801 e = expr_alloc_two(type: E_OR, e1, e2);
802 if (type == E_UNEQUAL)
803 e = expr_alloc_one(type: E_NOT, ce: e);
804 return e;
805 case E_OR:
806 e1 = expr_trans_compare(e: e->left.expr, type: E_EQUAL, sym);
807 e2 = expr_trans_compare(e: e->right.expr, type: E_EQUAL, sym);
808 if (sym == &symbol_yes)
809 e = expr_alloc_two(type: E_OR, e1, e2);
810 if (sym == &symbol_no)
811 e = expr_alloc_two(type: E_AND, e1, e2);
812 if (type == E_UNEQUAL)
813 e = expr_alloc_one(type: E_NOT, ce: e);
814 return e;
815 case E_NOT:
816 return expr_trans_compare(e: e->left.expr, type: 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(sym: &symbol_no);
828 if (sym == &symbol_no)
829 return expr_alloc_one(type: E_NOT, ce: e);
830 } else {
831 if (sym == &symbol_yes)
832 return expr_alloc_one(type: E_NOT, ce: e);
833 if (sym == &symbol_mod)
834 return expr_alloc_symbol(sym: &symbol_yes);
835 if (sym == &symbol_no)
836 return e;
837 }
838 break;
839 case E_SYMBOL:
840 return expr_alloc_comp(type, s1: e->left.sym, s2: 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(s1: str, s2: "n") ? 0 :
871 !strcmp(s1: str, s2: "m") ? 1 :
872 !strcmp(s1: str, s2: "y") ? 2 : -1;
873 return k_signed;
874 case S_INT:
875 val->s = strtoll(nptr: str, endptr: &tail, base: 10);
876 kind = k_signed;
877 break;
878 case S_HEX:
879 val->u = strtoull(nptr: str, endptr: &tail, base: 16);
880 kind = k_unsigned;
881 break;
882 default:
883 val->s = strtoll(nptr: str, endptr: &tail, base: 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(sym: e->left.sym);
902 return e->left.sym->curr.tri;
903 case E_AND:
904 val1 = expr_calc_value(e: e->left.expr);
905 val2 = expr_calc_value(e: e->right.expr);
906 return EXPR_AND(val1, val2);
907 case E_OR:
908 val1 = expr_calc_value(e: e->left.expr);
909 val2 = expr_calc_value(e: e->right.expr);
910 return EXPR_OR(val1, val2);
911 case E_NOT:
912 val1 = expr_calc_value(e: 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(format: "expr_calc_value: %d?\n", e->type);
923 return no;
924 }
925
926 sym_calc_value(sym: e->left.sym);
927 sym_calc_value(sym: e->right.sym);
928 str1 = sym_get_string_value(sym: e->left.sym);
929 str2 = sym_get_string_value(sym: e->right.sym);
930
931 if (e->left.sym->type != S_STRING || e->right.sym->type != S_STRING) {
932 k1 = expr_parse_string(str: str1, type: e->left.sym->type, val: &lval);
933 k2 = expr_parse_string(str: str2, type: e->right.sym->type, val: &rval);
934 }
935
936 if (k1 == k_string || k2 == k_string)
937 res = strcmp(s1: str1, s2: 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(format: "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(t1: prevtoken, t2: 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: e->left.expr, fn, data, prevtoken: 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: e->left.expr, fn, data, prevtoken: E_OR);
1080 fn(data, NULL, " || ");
1081 expr_print(e: e->right.expr, fn, data, prevtoken: E_OR);
1082 break;
1083 case E_AND:
1084 expr_print(e: e->left.expr, fn, data, prevtoken: E_AND);
1085 fn(data, NULL, " && ");
1086 expr_print(e: e->right.expr, fn, data, prevtoken: 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(s: buf, format: "<unknown type %d>", e->type);
1099 fn(data, NULL, buf);
1100 break;
1101 }
1102 }
1103 if (expr_compare_type(t1: prevtoken, t2: 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, len: strlen(s: str), count: 1, out: data);
1110}
1111
1112void expr_fprint(struct expr *e, FILE *out)
1113{
1114 expr_print(e, fn: expr_print_file_helper, data: out, prevtoken: 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(s: str);
1127 const char *last_cr = strrchr(s: gs->s, c: '\n');
1128 unsigned last_line_length;
1129
1130 if (sym_str)
1131 extra_length += 4 + strlen(s: sym_str);
1132
1133 if (!last_cr)
1134 last_cr = gs->s;
1135
1136 last_line_length = strlen(s: gs->s) - (last_cr - gs->s);
1137
1138 if ((last_line_length + extra_length) > gs->max_width)
1139 str_append(gs, s: "\\\n");
1140 }
1141
1142 str_append(gs, s: str);
1143 if (sym && sym->type != S_UNKNOWN)
1144 str_printf(gs, fmt: " [=%s]", sym_str);
1145}
1146
1147void expr_gstr_print(const struct expr *e, struct gstr *gs)
1148{
1149 expr_print(e, fn: expr_print_gstr_helper, data: gs, prevtoken: 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: e->left.expr, fn, data, pr_type, title);
1163 expr_print_revdep(e: 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, prevtoken: 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, fn: expr_print_gstr_helper, data: gs, pr_type, title: &title);
1180}
1181

source code of linux/scripts/kconfig/expr.c

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