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1/*
2 * Copyright (c) 2002 - 2005 Tony Finch <dot@dotat.at>. All rights reserved.
3 *
4 * This code is derived from software contributed to Berkeley by Dave Yost.
5 * It was rewritten to support ANSI C by Tony Finch. The original version of
6 * unifdef carried the following copyright notice. None of its code remains
7 * in this version (though some of the names remain).
8 *
9 * Copyright (c) 1985, 1993
10 * The Regents of the University of California. All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35
36#ifndef lint
37#if 0
38static const char copyright[] =
39"@(#) Copyright (c) 1985, 1993\n\
40 The Regents of the University of California. All rights reserved.\n";
41#endif
42#ifdef __IDSTRING
43__IDSTRING(Berkeley, "@(#)unifdef.c 8.1 (Berkeley) 6/6/93");
44__IDSTRING(NetBSD, "$NetBSD: unifdef.c,v 1.8 2000/07/03 02:51:36 matt Exp $");
45__IDSTRING(dotat, "$dotat: things/unifdef.c,v 1.171 2005/03/08 12:38:48 fanf2 Exp $");
46#endif
47#endif /* not lint */
48#ifdef __FBSDID
49__FBSDID("$FreeBSD: /repoman/r/ncvs/src/usr.bin/unifdef/unifdef.c,v 1.20 2005/05/21 09:55:09 ru Exp $");
50#endif
51
52/*
53 * unifdef - remove ifdef'ed lines
54 *
55 * Wishlist:
56 * provide an option which will append the name of the
57 * appropriate symbol after #else's and #endif's
58 * provide an option which will check symbols after
59 * #else's and #endif's to see that they match their
60 * corresponding #ifdef or #ifndef
61 *
62 * The first two items above require better buffer handling, which would
63 * also make it possible to handle all "dodgy" directives correctly.
64 */
65
66#include <ctype.h>
67#include <err.h>
68#include <stdarg.h>
69#include <stdbool.h>
70#include <stdio.h>
71#include <stdlib.h>
72#include <string.h>
73#include <unistd.h>
74
75size_t strlcpy(char *dst, const char *src, size_t siz);
76
77/* types of input lines: */
78typedef enum {
79 LT_TRUEI, /* a true #if with ignore flag */
80 LT_FALSEI, /* a false #if with ignore flag */
81 LT_IF, /* an unknown #if */
82 LT_TRUE, /* a true #if */
83 LT_FALSE, /* a false #if */
84 LT_ELIF, /* an unknown #elif */
85 LT_ELTRUE, /* a true #elif */
86 LT_ELFALSE, /* a false #elif */
87 LT_ELSE, /* #else */
88 LT_ENDIF, /* #endif */
89 LT_DODGY, /* flag: directive is not on one line */
90 LT_DODGY_LAST = LT_DODGY + LT_ENDIF,
91 LT_PLAIN, /* ordinary line */
92 LT_EOF, /* end of file */
93 LT_COUNT
94} Linetype;
95
96static char const * const linetype_name[] = {
97 "TRUEI", "FALSEI", "IF", "TRUE", "FALSE",
98 "ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF",
99 "DODGY TRUEI", "DODGY FALSEI",
100 "DODGY IF", "DODGY TRUE", "DODGY FALSE",
101 "DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE",
102 "DODGY ELSE", "DODGY ENDIF",
103 "PLAIN", "EOF"
104};
105
106/* state of #if processing */
107typedef enum {
108 IS_OUTSIDE,
109 IS_FALSE_PREFIX, /* false #if followed by false #elifs */
110 IS_TRUE_PREFIX, /* first non-false #(el)if is true */
111 IS_PASS_MIDDLE, /* first non-false #(el)if is unknown */
112 IS_FALSE_MIDDLE, /* a false #elif after a pass state */
113 IS_TRUE_MIDDLE, /* a true #elif after a pass state */
114 IS_PASS_ELSE, /* an else after a pass state */
115 IS_FALSE_ELSE, /* an else after a true state */
116 IS_TRUE_ELSE, /* an else after only false states */
117 IS_FALSE_TRAILER, /* #elifs after a true are false */
118 IS_COUNT
119} Ifstate;
120
121static char const * const ifstate_name[] = {
122 "OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX",
123 "PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE",
124 "PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE",
125 "FALSE_TRAILER"
126};
127
128/* state of comment parser */
129typedef enum {
130 NO_COMMENT = false, /* outside a comment */
131 C_COMMENT, /* in a comment like this one */
132 CXX_COMMENT, /* between // and end of line */
133 STARTING_COMMENT, /* just after slash-backslash-newline */
134 FINISHING_COMMENT, /* star-backslash-newline in a C comment */
135 CHAR_LITERAL, /* inside '' */
136 STRING_LITERAL /* inside "" */
137} Comment_state;
138
139static char const * const comment_name[] = {
140 "NO", "C", "CXX", "STARTING", "FINISHING", "CHAR", "STRING"
141};
142
143/* state of preprocessor line parser */
144typedef enum {
145 LS_START, /* only space and comments on this line */
146 LS_HASH, /* only space, comments, and a hash */
147 LS_DIRTY /* this line can't be a preprocessor line */
148} Line_state;
149
150static char const * const linestate_name[] = {
151 "START", "HASH", "DIRTY"
152};
153
154/*
155 * Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1
156 */
157#define MAXDEPTH 64 /* maximum #if nesting */
158#define MAXLINE 4096 /* maximum length of line */
159#define MAXSYMS 4096 /* maximum number of symbols */
160
161/*
162 * Sometimes when editing a keyword the replacement text is longer, so
163 * we leave some space at the end of the tline buffer to accommodate this.
164 */
165#define EDITSLOP 10
166
167/*
168 * Globals.
169 */
170
171static bool complement; /* -c: do the complement */
172static bool debugging; /* -d: debugging reports */
173static bool iocccok; /* -e: fewer IOCCC errors */
174static bool killconsts; /* -k: eval constant #ifs */
175static bool lnblank; /* -l: blank deleted lines */
176static bool lnnum; /* -n: add #line directives */
177static bool symlist; /* -s: output symbol list */
178static bool text; /* -t: this is a text file */
179
180static const char *symname[MAXSYMS]; /* symbol name */
181static const char *value[MAXSYMS]; /* -Dsym=value */
182static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */
183static int nsyms; /* number of symbols */
184
185static FILE *input; /* input file pointer */
186static const char *filename; /* input file name */
187static int linenum; /* current line number */
188
189static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */
190static char *keyword; /* used for editing #elif's */
191
192static Comment_state incomment; /* comment parser state */
193static Line_state linestate; /* #if line parser state */
194static Ifstate ifstate[MAXDEPTH]; /* #if processor state */
195static bool ignoring[MAXDEPTH]; /* ignore comments state */
196static int stifline[MAXDEPTH]; /* start of current #if */
197static int depth; /* current #if nesting */
198static int delcount; /* count of deleted lines */
199static bool keepthis; /* don't delete constant #if */
200
201static int exitstat; /* program exit status */
202
203static void addsym(bool, bool, char *);
204static void debug(const char *, ...);
205static void done(void);
206static void error(const char *);
207static int findsym(const char *);
208static void flushline(bool);
209static Linetype getline(void);
210static Linetype ifeval(const char **);
211static void ignoreoff(void);
212static void ignoreon(void);
213static void keywordedit(const char *);
214static void nest(void);
215static void process(void);
216static const char *skipcomment(const char *);
217static const char *skipsym(const char *);
218static void state(Ifstate);
219static int strlcmp(const char *, const char *, size_t);
220static void unnest(void);
221static void usage(void);
222
223#define endsym(c) (!isalpha((unsigned char)c) && !isdigit((unsigned char)c) && c != '_')
224
225/*
226 * The main program.
227 */
228int
229main(int argc, char *argv[])
230{
231 int opt;
232
233 while ((opt = getopt(argc, argv, "i:D:U:I:cdeklnst")) != -1)
234 switch (opt) {
235 case 'i': /* treat stuff controlled by these symbols as text */
236 /*
237 * For strict backwards-compatibility the U or D
238 * should be immediately after the -i but it doesn't
239 * matter much if we relax that requirement.
240 */
241 opt = *optarg++;
242 if (opt == 'D')
243 addsym(true, true, optarg);
244 else if (opt == 'U')
245 addsym(true, false, optarg);
246 else
247 usage();
248 break;
249 case 'D': /* define a symbol */
250 addsym(false, true, optarg);
251 break;
252 case 'U': /* undef a symbol */
253 addsym(false, false, optarg);
254 break;
255 case 'I':
256 /* no-op for compatibility with cpp */
257 break;
258 case 'c': /* treat -D as -U and vice versa */
259 complement = true;
260 break;
261 case 'd':
262 debugging = true;
263 break;
264 case 'e': /* fewer errors from dodgy lines */
265 iocccok = true;
266 break;
267 case 'k': /* process constant #ifs */
268 killconsts = true;
269 break;
270 case 'l': /* blank deleted lines instead of omitting them */
271 lnblank = true;
272 break;
273 case 'n': /* add #line directive after deleted lines */
274 lnnum = true;
275 break;
276 case 's': /* only output list of symbols that control #ifs */
277 symlist = true;
278 break;
279 case 't': /* don't parse C comments */
280 text = true;
281 break;
282 default:
283 usage();
284 }
285 argc -= optind;
286 argv += optind;
287 if (argc > 1) {
288 errx(2, "can only do one file");
289 } else if (argc == 1 && strcmp(*argv, "-") != 0) {
290 filename = *argv;
291 input = fopen(filename, "r");
292 if (input == NULL)
293 err(2, "can't open %s", filename);
294 } else {
295 filename = "[stdin]";
296 input = stdin;
297 }
298 process();
299 abort(); /* bug */
300}
301
302static void
303usage(void)
304{
305 fprintf(stderr, "usage: unifdef [-cdeklnst] [-Ipath]"
306 " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n");
307 exit(2);
308}
309
310/*
311 * A state transition function alters the global #if processing state
312 * in a particular way. The table below is indexed by the current
313 * processing state and the type of the current line.
314 *
315 * Nesting is handled by keeping a stack of states; some transition
316 * functions increase or decrease the depth. They also maintain the
317 * ignore state on a stack. In some complicated cases they have to
318 * alter the preprocessor directive, as follows.
319 *
320 * When we have processed a group that starts off with a known-false
321 * #if/#elif sequence (which has therefore been deleted) followed by a
322 * #elif that we don't understand and therefore must keep, we edit the
323 * latter into a #if to keep the nesting correct.
324 *
325 * When we find a true #elif in a group, the following block will
326 * always be kept and the rest of the sequence after the next #elif or
327 * #else will be discarded. We edit the #elif into a #else and the
328 * following directive to #endif since this has the desired behaviour.
329 *
330 * "Dodgy" directives are split across multiple lines, the most common
331 * example being a multi-line comment hanging off the right of the
332 * directive. We can handle them correctly only if there is no change
333 * from printing to dropping (or vice versa) caused by that directive.
334 * If the directive is the first of a group we have a choice between
335 * failing with an error, or passing it through unchanged instead of
336 * evaluating it. The latter is not the default to avoid questions from
337 * users about unifdef unexpectedly leaving behind preprocessor directives.
338 */
339typedef void state_fn(void);
340
341/* report an error */
342static void Eelif (void) { error("Inappropriate #elif"); }
343static void Eelse (void) { error("Inappropriate #else"); }
344static void Eendif(void) { error("Inappropriate #endif"); }
345static void Eeof (void) { error("Premature EOF"); }
346static void Eioccc(void) { error("Obfuscated preprocessor control line"); }
347/* plain line handling */
348static void print (void) { flushline(true); }
349static void drop (void) { flushline(false); }
350/* output lacks group's start line */
351static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); }
352static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); }
353static void Selse (void) { drop(); state(IS_TRUE_ELSE); }
354/* print/pass this block */
355static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); }
356static void Pelse (void) { print(); state(IS_PASS_ELSE); }
357static void Pendif(void) { print(); unnest(); }
358/* discard this block */
359static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); }
360static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); }
361static void Delse (void) { drop(); state(IS_FALSE_ELSE); }
362static void Dendif(void) { drop(); unnest(); }
363/* first line of group */
364static void Fdrop (void) { nest(); Dfalse(); }
365static void Fpass (void) { nest(); Pelif(); }
366static void Ftrue (void) { nest(); Strue(); }
367static void Ffalse(void) { nest(); Sfalse(); }
368/* variable pedantry for obfuscated lines */
369static void Oiffy (void) { if (!iocccok) Eioccc(); Fpass(); ignoreon(); }
370static void Oif (void) { if (!iocccok) Eioccc(); Fpass(); }
371static void Oelif (void) { if (!iocccok) Eioccc(); Pelif(); }
372/* ignore comments in this block */
373static void Idrop (void) { Fdrop(); ignoreon(); }
374static void Itrue (void) { Ftrue(); ignoreon(); }
375static void Ifalse(void) { Ffalse(); ignoreon(); }
376/* edit this line */
377static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); }
378static void Mtrue (void) { keywordedit("else\n"); state(IS_TRUE_MIDDLE); }
379static void Melif (void) { keywordedit("endif\n"); state(IS_FALSE_TRAILER); }
380static void Melse (void) { keywordedit("endif\n"); state(IS_FALSE_ELSE); }
381
382static state_fn * const trans_table[IS_COUNT][LT_COUNT] = {
383/* IS_OUTSIDE */
384{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif,
385 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif,
386 print, done },
387/* IS_FALSE_PREFIX */
388{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif,
389 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc,
390 drop, Eeof },
391/* IS_TRUE_PREFIX */
392{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif,
393 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
394 print, Eeof },
395/* IS_PASS_MIDDLE */
396{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif,
397 Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif,
398 print, Eeof },
399/* IS_FALSE_MIDDLE */
400{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif,
401 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
402 drop, Eeof },
403/* IS_TRUE_MIDDLE */
404{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif,
405 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif,
406 print, Eeof },
407/* IS_PASS_ELSE */
408{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif,
409 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif,
410 print, Eeof },
411/* IS_FALSE_ELSE */
412{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif,
413 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc,
414 drop, Eeof },
415/* IS_TRUE_ELSE */
416{ Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif,
417 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc,
418 print, Eeof },
419/* IS_FALSE_TRAILER */
420{ Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif,
421 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc,
422 drop, Eeof }
423/*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF
424 TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY)
425 PLAIN EOF */
426};
427
428/*
429 * State machine utility functions
430 */
431static void
432done(void)
433{
434 if (incomment)
435 error("EOF in comment");
436 exit(exitstat);
437}
438static void
439ignoreoff(void)
440{
441 if (depth == 0)
442 abort(); /* bug */
443 ignoring[depth] = ignoring[depth-1];
444}
445static void
446ignoreon(void)
447{
448 ignoring[depth] = true;
449}
450static void
451keywordedit(const char *replacement)
452{
453 size_t size = tline + sizeof(tline) - keyword;
454 char *dst = keyword;
455 const char *src = replacement;
456 if (size != 0) {
457 while ((--size != 0) && (*src != '\0'))
458 *dst++ = *src++;
459 *dst = '\0';
460 }
461 print();
462}
463static void
464nest(void)
465{
466 depth += 1;
467 if (depth >= MAXDEPTH)
468 error("Too many levels of nesting");
469 stifline[depth] = linenum;
470}
471static void
472unnest(void)
473{
474 if (depth == 0)
475 abort(); /* bug */
476 depth -= 1;
477}
478static void
479state(Ifstate is)
480{
481 ifstate[depth] = is;
482}
483
484/*
485 * Write a line to the output or not, according to command line options.
486 */
487static void
488flushline(bool keep)
489{
490 if (symlist)
491 return;
492 if (keep ^ complement) {
493 if (lnnum && delcount > 0)
494 printf("#line %d\n", linenum);
495 fputs(tline, stdout);
496 delcount = 0;
497 } else {
498 if (lnblank)
499 putc('\n', stdout);
500 exitstat = 1;
501 delcount += 1;
502 }
503}
504
505/*
506 * The driver for the state machine.
507 */
508static void
509process(void)
510{
511 Linetype lineval;
512
513 for (;;) {
514 linenum++;
515 lineval = getline();
516 trans_table[ifstate[depth]][lineval]();
517 debug("process %s -> %s depth %d",
518 linetype_name[lineval],
519 ifstate_name[ifstate[depth]], depth);
520 }
521}
522
523/*
524 * Parse a line and determine its type. We keep the preprocessor line
525 * parser state between calls in the global variable linestate, with
526 * help from skipcomment().
527 */
528static Linetype
529getline(void)
530{
531 const char *cp;
532 int cursym;
533 int kwlen;
534 Linetype retval;
535 Comment_state wascomment;
536
537 if (fgets(tline, MAXLINE, input) == NULL)
538 return (LT_EOF);
539 retval = LT_PLAIN;
540 wascomment = incomment;
541 cp = skipcomment(tline);
542 if (linestate == LS_START) {
543 if (*cp == '#') {
544 linestate = LS_HASH;
545 cp = skipcomment(cp + 1);
546 } else if (*cp != '\0')
547 linestate = LS_DIRTY;
548 }
549 if (!incomment && linestate == LS_HASH) {
550 keyword = tline + (cp - tline);
551 cp = skipsym(cp);
552 kwlen = cp - keyword;
553 /* no way can we deal with a continuation inside a keyword */
554 if (strncmp(cp, "\\\n", 2) == 0)
555 Eioccc();
556 if (strlcmp("ifdef", keyword, kwlen) == 0 ||
557 strlcmp("ifndef", keyword, kwlen) == 0) {
558 cp = skipcomment(cp);
559 if ((cursym = findsym(cp)) < 0)
560 retval = LT_IF;
561 else {
562 retval = (keyword[2] == 'n')
563 ? LT_FALSE : LT_TRUE;
564 if (value[cursym] == NULL)
565 retval = (retval == LT_TRUE)
566 ? LT_FALSE : LT_TRUE;
567 if (ignore[cursym])
568 retval = (retval == LT_TRUE)
569 ? LT_TRUEI : LT_FALSEI;
570 }
571 cp = skipsym(cp);
572 } else if (strlcmp("if", keyword, kwlen) == 0)
573 retval = ifeval(&cp);
574 else if (strlcmp("elif", keyword, kwlen) == 0)
575 retval = ifeval(&cp) - LT_IF + LT_ELIF;
576 else if (strlcmp("else", keyword, kwlen) == 0)
577 retval = LT_ELSE;
578 else if (strlcmp("endif", keyword, kwlen) == 0)
579 retval = LT_ENDIF;
580 else {
581 linestate = LS_DIRTY;
582 retval = LT_PLAIN;
583 }
584 cp = skipcomment(cp);
585 if (*cp != '\0') {
586 linestate = LS_DIRTY;
587 if (retval == LT_TRUE || retval == LT_FALSE ||
588 retval == LT_TRUEI || retval == LT_FALSEI)
589 retval = LT_IF;
590 if (retval == LT_ELTRUE || retval == LT_ELFALSE)
591 retval = LT_ELIF;
592 }
593 if (retval != LT_PLAIN && (wascomment || incomment)) {
594 retval += LT_DODGY;
595 if (incomment)
596 linestate = LS_DIRTY;
597 }
598 /* skipcomment should have changed the state */
599 if (linestate == LS_HASH)
600 abort(); /* bug */
601 }
602 if (linestate == LS_DIRTY) {
603 while (*cp != '\0')
604 cp = skipcomment(cp + 1);
605 }
606 debug("parser %s comment %s line",
607 comment_name[incomment], linestate_name[linestate]);
608 return (retval);
609}
610
611/*
612 * These are the binary operators that are supported by the expression
613 * evaluator. Note that if support for division is added then we also
614 * need short-circuiting booleans because of divide-by-zero.
615 */
616static int op_lt(int a, int b) { return (a < b); }
617static int op_gt(int a, int b) { return (a > b); }
618static int op_le(int a, int b) { return (a <= b); }
619static int op_ge(int a, int b) { return (a >= b); }
620static int op_eq(int a, int b) { return (a == b); }
621static int op_ne(int a, int b) { return (a != b); }
622static int op_or(int a, int b) { return (a || b); }
623static int op_and(int a, int b) { return (a && b); }
624
625/*
626 * An evaluation function takes three arguments, as follows: (1) a pointer to
627 * an element of the precedence table which lists the operators at the current
628 * level of precedence; (2) a pointer to an integer which will receive the
629 * value of the expression; and (3) a pointer to a char* that points to the
630 * expression to be evaluated and that is updated to the end of the expression
631 * when evaluation is complete. The function returns LT_FALSE if the value of
632 * the expression is zero, LT_TRUE if it is non-zero, or LT_IF if the
633 * expression could not be evaluated.
634 */
635struct ops;
636
637typedef Linetype eval_fn(const struct ops *, int *, const char **);
638
639static eval_fn eval_table, eval_unary;
640
641/*
642 * The precedence table. Expressions involving binary operators are evaluated
643 * in a table-driven way by eval_table. When it evaluates a subexpression it
644 * calls the inner function with its first argument pointing to the next
645 * element of the table. Innermost expressions have special non-table-driven
646 * handling.
647 */
648static const struct ops {
649 eval_fn *inner;
650 struct op {
651 const char *str;
652 int (*fn)(int, int);
653 } op[5];
654} eval_ops[] = {
655 { eval_table, { { "||", op_or } } },
656 { eval_table, { { "&&", op_and } } },
657 { eval_table, { { "==", op_eq },
658 { "!=", op_ne } } },
659 { eval_unary, { { "<=", op_le },
660 { ">=", op_ge },
661 { "<", op_lt },
662 { ">", op_gt } } }
663};
664
665/*
666 * Function for evaluating the innermost parts of expressions,
667 * viz. !expr (expr) defined(symbol) symbol number
668 * We reset the keepthis flag when we find a non-constant subexpression.
669 */
670static Linetype
671eval_unary(const struct ops *ops, int *valp, const char **cpp)
672{
673 const char *cp;
674 char *ep;
675 int sym;
676
677 cp = skipcomment(*cpp);
678 if (*cp == '!') {
679 debug("eval%d !", ops - eval_ops);
680 cp++;
681 if (eval_unary(ops, valp, &cp) == LT_IF)
682 return (LT_IF);
683 *valp = !*valp;
684 } else if (*cp == '(') {
685 cp++;
686 debug("eval%d (", ops - eval_ops);
687 if (eval_table(eval_ops, valp, &cp) == LT_IF)
688 return (LT_IF);
689 cp = skipcomment(cp);
690 if (*cp++ != ')')
691 return (LT_IF);
692 } else if (isdigit((unsigned char)*cp)) {
693 debug("eval%d number", ops - eval_ops);
694 *valp = strtol(cp, &ep, 0);
695 cp = skipsym(cp);
696 } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) {
697 cp = skipcomment(cp+7);
698 debug("eval%d defined", ops - eval_ops);
699 if (*cp++ != '(')
700 return (LT_IF);
701 cp = skipcomment(cp);
702 sym = findsym(cp);
703 if (sym < 0)
704 return (LT_IF);
705 *valp = (value[sym] != NULL);
706 cp = skipsym(cp);
707 cp = skipcomment(cp);
708 if (*cp++ != ')')
709 return (LT_IF);
710 keepthis = false;
711 } else if (!endsym(*cp)) {
712 debug("eval%d symbol", ops - eval_ops);
713 sym = findsym(cp);
714 if (sym < 0)
715 return (LT_IF);
716 if (value[sym] == NULL)
717 *valp = 0;
718 else {
719 *valp = strtol(value[sym], &ep, 0);
720 if (*ep != '\0' || ep == value[sym])
721 return (LT_IF);
722 }
723 cp = skipsym(cp);
724 keepthis = false;
725 } else {
726 debug("eval%d bad expr", ops - eval_ops);
727 return (LT_IF);
728 }
729
730 *cpp = cp;
731 debug("eval%d = %d", ops - eval_ops, *valp);
732 return (*valp ? LT_TRUE : LT_FALSE);
733}
734
735/*
736 * Table-driven evaluation of binary operators.
737 */
738static Linetype
739eval_table(const struct ops *ops, int *valp, const char **cpp)
740{
741 const struct op *op;
742 const char *cp;
743 int val;
744
745 debug("eval%d", ops - eval_ops);
746 cp = *cpp;
747 if (ops->inner(ops+1, valp, &cp) == LT_IF)
748 return (LT_IF);
749 for (;;) {
750 cp = skipcomment(cp);
751 for (op = ops->op; op->str != NULL; op++)
752 if (strncmp(cp, op->str, strlen(op->str)) == 0)
753 break;
754 if (op->str == NULL)
755 break;
756 cp += strlen(op->str);
757 debug("eval%d %s", ops - eval_ops, op->str);
758 if (ops->inner(ops+1, &val, &cp) == LT_IF)
759 return (LT_IF);
760 *valp = op->fn(*valp, val);
761 }
762
763 *cpp = cp;
764 debug("eval%d = %d", ops - eval_ops, *valp);
765 return (*valp ? LT_TRUE : LT_FALSE);
766}
767
768/*
769 * Evaluate the expression on a #if or #elif line. If we can work out
770 * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we
771 * return just a generic LT_IF.
772 */
773static Linetype
774ifeval(const char **cpp)
775{
776 int ret;
777 int val;
778
779 debug("eval %s", *cpp);
780 keepthis = killconsts ? false : true;
781 ret = eval_table(eval_ops, &val, cpp);
782 debug("eval = %d", val);
783 return (keepthis ? LT_IF : ret);
784}
785
786/*
787 * Skip over comments, strings, and character literals and stop at the
788 * next character position that is not whitespace. Between calls we keep
789 * the comment state in the global variable incomment, and we also adjust
790 * the global variable linestate when we see a newline.
791 * XXX: doesn't cope with the buffer splitting inside a state transition.
792 */
793static const char *
794skipcomment(const char *cp)
795{
796 if (text || ignoring[depth]) {
797 for (; isspace((unsigned char)*cp); cp++)
798 if (*cp == '\n')
799 linestate = LS_START;
800 return (cp);
801 }
802 while (*cp != '\0')
803 /* don't reset to LS_START after a line continuation */
804 if (strncmp(cp, "\\\n", 2) == 0)
805 cp += 2;
806 else switch (incomment) {
807 case NO_COMMENT:
808 if (strncmp(cp, "/\\\n", 3) == 0) {
809 incomment = STARTING_COMMENT;
810 cp += 3;
811 } else if (strncmp(cp, "/*", 2) == 0) {
812 incomment = C_COMMENT;
813 cp += 2;
814 } else if (strncmp(cp, "//", 2) == 0) {
815 incomment = CXX_COMMENT;
816 cp += 2;
817 } else if (strncmp(cp, "\'", 1) == 0) {
818 incomment = CHAR_LITERAL;
819 linestate = LS_DIRTY;
820 cp += 1;
821 } else if (strncmp(cp, "\"", 1) == 0) {
822 incomment = STRING_LITERAL;
823 linestate = LS_DIRTY;
824 cp += 1;
825 } else if (strncmp(cp, "\n", 1) == 0) {
826 linestate = LS_START;
827 cp += 1;
828 } else if (strchr(" \t", *cp) != NULL) {
829 cp += 1;
830 } else
831 return (cp);
832 continue;
833 case CXX_COMMENT:
834 if (strncmp(cp, "\n", 1) == 0) {
835 incomment = NO_COMMENT;
836 linestate = LS_START;
837 }
838 cp += 1;
839 continue;
840 case CHAR_LITERAL:
841 case STRING_LITERAL:
842 if ((incomment == CHAR_LITERAL && cp[0] == '\'') ||
843 (incomment == STRING_LITERAL && cp[0] == '\"')) {
844 incomment = NO_COMMENT;
845 cp += 1;
846 } else if (cp[0] == '\\') {
847 if (cp[1] == '\0')
848 cp += 1;
849 else
850 cp += 2;
851 } else if (strncmp(cp, "\n", 1) == 0) {
852 if (incomment == CHAR_LITERAL)
853 error("unterminated char literal");
854 else
855 error("unterminated string literal");
856 } else
857 cp += 1;
858 continue;
859 case C_COMMENT:
860 if (strncmp(cp, "*\\\n", 3) == 0) {
861 incomment = FINISHING_COMMENT;
862 cp += 3;
863 } else if (strncmp(cp, "*/", 2) == 0) {
864 incomment = NO_COMMENT;
865 cp += 2;
866 } else
867 cp += 1;
868 continue;
869 case STARTING_COMMENT:
870 if (*cp == '*') {
871 incomment = C_COMMENT;
872 cp += 1;
873 } else if (*cp == '/') {
874 incomment = CXX_COMMENT;
875 cp += 1;
876 } else {
877 incomment = NO_COMMENT;
878 linestate = LS_DIRTY;
879 }
880 continue;
881 case FINISHING_COMMENT:
882 if (*cp == '/') {
883 incomment = NO_COMMENT;
884 cp += 1;
885 } else
886 incomment = C_COMMENT;
887 continue;
888 default:
889 abort(); /* bug */
890 }
891 return (cp);
892}
893
894/*
895 * Skip over an identifier.
896 */
897static const char *
898skipsym(const char *cp)
899{
900 while (!endsym(*cp))
901 ++cp;
902 return (cp);
903}
904
905/*
906 * Look for the symbol in the symbol table. If is is found, we return
907 * the symbol table index, else we return -1.
908 */
909static int
910findsym(const char *str)
911{
912 const char *cp;
913 int symind;
914
915 cp = skipsym(str);
916 if (cp == str)
917 return (-1);
918 if (symlist) {
919 printf("%.*s\n", (int)(cp-str), str);
920 /* we don't care about the value of the symbol */
921 return (0);
922 }
923 for (symind = 0; symind < nsyms; ++symind) {
924 if (strlcmp(symname[symind], str, cp-str) == 0) {
925 debug("findsym %s %s", symname[symind],
926 value[symind] ? value[symind] : "");
927 return (symind);
928 }
929 }
930 return (-1);
931}
932
933/*
934 * Add a symbol to the symbol table.
935 */
936static void
937addsym(bool ignorethis, bool definethis, char *sym)
938{
939 int symind;
940 char *val;
941
942 symind = findsym(sym);
943 if (symind < 0) {
944 if (nsyms >= MAXSYMS)
945 errx(2, "too many symbols");
946 symind = nsyms++;
947 }
948 symname[symind] = sym;
949 ignore[symind] = ignorethis;
950 val = sym + (skipsym(sym) - sym);
951 if (definethis) {
952 if (*val == '=') {
953 value[symind] = val+1;
954 *val = '\0';
955 } else if (*val == '\0')
956 value[symind] = "";
957 else
958 usage();
959 } else {
960 if (*val != '\0')
961 usage();
962 value[symind] = NULL;
963 }
964}
965
966/*
967 * Compare s with n characters of t.
968 * The same as strncmp() except that it checks that s[n] == '\0'.
969 */
970static int
971strlcmp(const char *s, const char *t, size_t n)
972{
973 while (n-- && *t != '\0')
974 if (*s != *t)
975 return ((unsigned char)*s - (unsigned char)*t);
976 else
977 ++s, ++t;
978 return ((unsigned char)*s);
979}
980
981/*
982 * Diagnostics.
983 */
984static void
985debug(const char *msg, ...)
986{
987 va_list ap;
988
989 if (debugging) {
990 va_start(ap, msg);
991 vwarnx(msg, ap);
992 va_end(ap);
993 }
994}
995
996static void
997error(const char *msg)
998{
999 if (depth == 0)
1000 warnx("%s: %d: %s", filename, linenum, msg);
1001 else
1002 warnx("%s: %d: %s (#if line %d depth %d)",
1003 filename, linenum, msg, stifline[depth], depth);
1004 errx(2, "output may be truncated");
1005}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-11-16 07:30:11 +0000