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ocfs2: Make the left masklogs compat.
[taoma-kernel.git] / scripts / unifdef.c
blob44d39785e50da4a67bdde65a86e55b6a795e55b3
1 /*
2 * Copyright (c) 2002 - 2009 Tony Finch <dot@dotat.at>
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 /*
27 * This code was derived from software contributed to Berkeley by Dave Yost.
28 * It was rewritten to support ANSI C by Tony Finch. The original version
29 * of unifdef carried the 4-clause BSD copyright licence. None of its code
30 * remains in this version (though some of the names remain) so it now
31 * carries a more liberal licence.
32 *
33 * The latest version is available from http://dotat.at/prog/unifdef
34 */
35
36 static const char * const copyright[] = {
37 "@(#) Copyright (c) 2002 - 2009 Tony Finch <dot@dotat.at>\n",
38 "$dotat: unifdef/unifdef.c,v 1.190 2009/11/27 17:21:26 fanf2 Exp $",
39 };
40
41 /*
42 * unifdef - remove ifdef'ed lines
43 *
44 * Wishlist:
45 * provide an option which will append the name of the
46 * appropriate symbol after #else's and #endif's
47 * provide an option which will check symbols after
48 * #else's and #endif's to see that they match their
49 * corresponding #ifdef or #ifndef
50 *
51 * The first two items above require better buffer handling, which would
52 * also make it possible to handle all "dodgy" directives correctly.
53 */
54
55 #include <ctype.h>
56 #include <err.h>
57 #include <stdarg.h>
58 #include <stdbool.h>
59 #include <stdio.h>
60 #include <stdlib.h>
61 #include <string.h>
62 #include <unistd.h>
63
64 /* types of input lines: */
65 typedef enum {
66 LT_TRUEI, /* a true #if with ignore flag */
67 LT_FALSEI, /* a false #if with ignore flag */
68 LT_IF, /* an unknown #if */
69 LT_TRUE, /* a true #if */
70 LT_FALSE, /* a false #if */
71 LT_ELIF, /* an unknown #elif */
72 LT_ELTRUE, /* a true #elif */
73 LT_ELFALSE, /* a false #elif */
74 LT_ELSE, /* #else */
75 LT_ENDIF, /* #endif */
76 LT_DODGY, /* flag: directive is not on one line */
77 LT_DODGY_LAST = LT_DODGY + LT_ENDIF,
78 LT_PLAIN, /* ordinary line */
79 LT_EOF, /* end of file */
80 LT_ERROR, /* unevaluable #if */
81 LT_COUNT
82 } Linetype;
83
84 static char const * const linetype_name[] = {
85 "TRUEI", "FALSEI", "IF", "TRUE", "FALSE",
86 "ELIF", "ELTRUE", "ELFALSE", "ELSE", "ENDIF",
87 "DODGY TRUEI", "DODGY FALSEI",
88 "DODGY IF", "DODGY TRUE", "DODGY FALSE",
89 "DODGY ELIF", "DODGY ELTRUE", "DODGY ELFALSE",
90 "DODGY ELSE", "DODGY ENDIF",
91 "PLAIN", "EOF", "ERROR"
92 };
93
94 /* state of #if processing */
95 typedef enum {
96 IS_OUTSIDE,
97 IS_FALSE_PREFIX, /* false #if followed by false #elifs */
98 IS_TRUE_PREFIX, /* first non-false #(el)if is true */
99 IS_PASS_MIDDLE, /* first non-false #(el)if is unknown */
100 IS_FALSE_MIDDLE, /* a false #elif after a pass state */
101 IS_TRUE_MIDDLE, /* a true #elif after a pass state */
102 IS_PASS_ELSE, /* an else after a pass state */
103 IS_FALSE_ELSE, /* an else after a true state */
104 IS_TRUE_ELSE, /* an else after only false states */
105 IS_FALSE_TRAILER, /* #elifs after a true are false */
106 IS_COUNT
107 } Ifstate;
108
109 static char const * const ifstate_name[] = {
110 "OUTSIDE", "FALSE_PREFIX", "TRUE_PREFIX",
111 "PASS_MIDDLE", "FALSE_MIDDLE", "TRUE_MIDDLE",
112 "PASS_ELSE", "FALSE_ELSE", "TRUE_ELSE",
113 "FALSE_TRAILER"
114 };
115
116 /* state of comment parser */
117 typedef enum {
118 NO_COMMENT = false, /* outside a comment */
119 C_COMMENT, /* in a comment like this one */
120 CXX_COMMENT, /* between // and end of line */
121 STARTING_COMMENT, /* just after slash-backslash-newline */
122 FINISHING_COMMENT, /* star-backslash-newline in a C comment */
123 CHAR_LITERAL, /* inside '' */
124 STRING_LITERAL /* inside "" */
125 } Comment_state;
126
127 static char const * const comment_name[] = {
128 "NO", "C", "CXX", "STARTING", "FINISHING", "CHAR", "STRING"
129 };
130
131 /* state of preprocessor line parser */
132 typedef enum {
133 LS_START, /* only space and comments on this line */
134 LS_HASH, /* only space, comments, and a hash */
135 LS_DIRTY /* this line can't be a preprocessor line */
136 } Line_state;
137
138 static char const * const linestate_name[] = {
139 "START", "HASH", "DIRTY"
140 };
141
142 /*
143 * Minimum translation limits from ISO/IEC 9899:1999 5.2.4.1
144 */
145 #define MAXDEPTH 64 /* maximum #if nesting */
146 #define MAXLINE 4096 /* maximum length of line */
147 #define MAXSYMS 4096 /* maximum number of symbols */
148
149 /*
150 * Sometimes when editing a keyword the replacement text is longer, so
151 * we leave some space at the end of the tline buffer to accommodate this.
152 */
153 #define EDITSLOP 10
154
155 /*
156 * Globals.
157 */
158
159 static bool compblank; /* -B: compress blank lines */
160 static bool lnblank; /* -b: blank deleted lines */
161 static bool complement; /* -c: do the complement */
162 static bool debugging; /* -d: debugging reports */
163 static bool iocccok; /* -e: fewer IOCCC errors */
164 static bool strictlogic; /* -K: keep ambiguous #ifs */
165 static bool killconsts; /* -k: eval constant #ifs */
166 static bool lnnum; /* -n: add #line directives */
167 static bool symlist; /* -s: output symbol list */
168 static bool text; /* -t: this is a text file */
169
170 static const char *symname[MAXSYMS]; /* symbol name */
171 static const char *value[MAXSYMS]; /* -Dsym=value */
172 static bool ignore[MAXSYMS]; /* -iDsym or -iUsym */
173 static int nsyms; /* number of symbols */
174
175 static FILE *input; /* input file pointer */
176 static const char *filename; /* input file name */
177 static int linenum; /* current line number */
178
179 static char tline[MAXLINE+EDITSLOP];/* input buffer plus space */
180 static char *keyword; /* used for editing #elif's */
181
182 static Comment_state incomment; /* comment parser state */
183 static Line_state linestate; /* #if line parser state */
184 static Ifstate ifstate[MAXDEPTH]; /* #if processor state */
185 static bool ignoring[MAXDEPTH]; /* ignore comments state */
186 static int stifline[MAXDEPTH]; /* start of current #if */
187 static int depth; /* current #if nesting */
188 static int delcount; /* count of deleted lines */
189 static unsigned blankcount; /* count of blank lines */
190 static unsigned blankmax; /* maximum recent blankcount */
191 static bool constexpr; /* constant #if expression */
192
193 static int exitstat; /* program exit status */
194
195 static void addsym(bool, bool, char *);
196 static void debug(const char *, ...);
197 static void done(void);
198 static void error(const char *);
199 static int findsym(const char *);
200 static void flushline(bool);
201 static Linetype parseline(void);
202 static Linetype ifeval(const char **);
203 static void ignoreoff(void);
204 static void ignoreon(void);
205 static void keywordedit(const char *);
206 static void nest(void);
207 static void process(void);
208 static const char *skipargs(const char *);
209 static const char *skipcomment(const char *);
210 static const char *skipsym(const char *);
211 static void state(Ifstate);
212 static int strlcmp(const char *, const char *, size_t);
213 static void unnest(void);
214 static void usage(void);
215
216 #define endsym(c) (!isalnum((unsigned char)c) && c != '_')
217
218 /*
219 * The main program.
220 */
221 int
222 main(int argc, char *argv[])
223 {
224 int opt;
225
226 while ((opt = getopt(argc, argv, "i:D:U:I:BbcdeKklnst")) != -1)
227 switch (opt) {
228 case 'i': /* treat stuff controlled by these symbols as text */
229 /*
230 * For strict backwards-compatibility the U or D
231 * should be immediately after the -i but it doesn't
232 * matter much if we relax that requirement.
233 */
234 opt = *optarg++;
235 if (opt == 'D')
236 addsym(true, true, optarg);
237 else if (opt == 'U')
238 addsym(true, false, optarg);
239 else
240 usage();
241 break;
242 case 'D': /* define a symbol */
243 addsym(false, true, optarg);
244 break;
245 case 'U': /* undef a symbol */
246 addsym(false, false, optarg);
247 break;
248 case 'I':
249 /* no-op for compatibility with cpp */
250 break;
251 case 'B': /* compress blank lines around removed section */
252 compblank = true;
253 break;
254 case 'b': /* blank deleted lines instead of omitting them */
255 case 'l': /* backwards compatibility */
256 lnblank = true;
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': /* keep ambiguous #ifs */
268 strictlogic = true;
269 break;
270 case 'k': /* process constant #ifs */
271 killconsts = 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 (compblank && lnblank)
288 errx(2, "-B and -b are mutually exclusive");
289 if (argc > 1) {
290 errx(2, "can only do one file");
291 } else if (argc == 1 && strcmp(*argv, "-") != 0) {
292 filename = *argv;
293 input = fopen(filename, "r");
294 if (input == NULL)
295 err(2, "can't open %s", filename);
296 } else {
297 filename = "[stdin]";
298 input = stdin;
299 }
300 process();
301 abort(); /* bug */
302 }
303
304 static void
305 usage(void)
306 {
307 fprintf(stderr, "usage: unifdef [-BbcdeKknst] [-Ipath]"
308 " [-Dsym[=val]] [-Usym] [-iDsym[=val]] [-iUsym] ... [file]\n");
309 exit(2);
310 }
311
312 /*
313 * A state transition function alters the global #if processing state
314 * in a particular way. The table below is indexed by the current
315 * processing state and the type of the current line.
316 *
317 * Nesting is handled by keeping a stack of states; some transition
318 * functions increase or decrease the depth. They also maintain the
319 * ignore state on a stack. In some complicated cases they have to
320 * alter the preprocessor directive, as follows.
321 *
322 * When we have processed a group that starts off with a known-false
323 * #if/#elif sequence (which has therefore been deleted) followed by a
324 * #elif that we don't understand and therefore must keep, we edit the
325 * latter into a #if to keep the nesting correct.
326 *
327 * When we find a true #elif in a group, the following block will
328 * always be kept and the rest of the sequence after the next #elif or
329 * #else will be discarded. We edit the #elif into a #else and the
330 * following directive to #endif since this has the desired behaviour.
331 *
332 * "Dodgy" directives are split across multiple lines, the most common
333 * example being a multi-line comment hanging off the right of the
334 * directive. We can handle them correctly only if there is no change
335 * from printing to dropping (or vice versa) caused by that directive.
336 * If the directive is the first of a group we have a choice between
337 * failing with an error, or passing it through unchanged instead of
338 * evaluating it. The latter is not the default to avoid questions from
339 * users about unifdef unexpectedly leaving behind preprocessor directives.
340 */
341 typedef void state_fn(void);
342
343 /* report an error */
344 static void Eelif (void) { error("Inappropriate #elif"); }
345 static void Eelse (void) { error("Inappropriate #else"); }
346 static void Eendif(void) { error("Inappropriate #endif"); }
347 static void Eeof (void) { error("Premature EOF"); }
348 static void Eioccc(void) { error("Obfuscated preprocessor control line"); }
349 /* plain line handling */
350 static void print (void) { flushline(true); }
351 static void drop (void) { flushline(false); }
352 /* output lacks group's start line */
353 static void Strue (void) { drop(); ignoreoff(); state(IS_TRUE_PREFIX); }
354 static void Sfalse(void) { drop(); ignoreoff(); state(IS_FALSE_PREFIX); }
355 static void Selse (void) { drop(); state(IS_TRUE_ELSE); }
356 /* print/pass this block */
357 static void Pelif (void) { print(); ignoreoff(); state(IS_PASS_MIDDLE); }
358 static void Pelse (void) { print(); state(IS_PASS_ELSE); }
359 static void Pendif(void) { print(); unnest(); }
360 /* discard this block */
361 static void Dfalse(void) { drop(); ignoreoff(); state(IS_FALSE_TRAILER); }
362 static void Delif (void) { drop(); ignoreoff(); state(IS_FALSE_MIDDLE); }
363 static void Delse (void) { drop(); state(IS_FALSE_ELSE); }
364 static void Dendif(void) { drop(); unnest(); }
365 /* first line of group */
366 static void Fdrop (void) { nest(); Dfalse(); }
367 static void Fpass (void) { nest(); Pelif(); }
368 static void Ftrue (void) { nest(); Strue(); }
369 static void Ffalse(void) { nest(); Sfalse(); }
370 /* variable pedantry for obfuscated lines */
371 static void Oiffy (void) { if (!iocccok) Eioccc(); Fpass(); ignoreon(); }
372 static void Oif (void) { if (!iocccok) Eioccc(); Fpass(); }
373 static void Oelif (void) { if (!iocccok) Eioccc(); Pelif(); }
374 /* ignore comments in this block */
375 static void Idrop (void) { Fdrop(); ignoreon(); }
376 static void Itrue (void) { Ftrue(); ignoreon(); }
377 static void Ifalse(void) { Ffalse(); ignoreon(); }
378 /* edit this line */
379 static void Mpass (void) { strncpy(keyword, "if ", 4); Pelif(); }
380 static void Mtrue (void) { keywordedit("else\n"); state(IS_TRUE_MIDDLE); }
381 static void Melif (void) { keywordedit("endif\n"); state(IS_FALSE_TRAILER); }
382 static void Melse (void) { keywordedit("endif\n"); state(IS_FALSE_ELSE); }
383
384 static state_fn * const trans_table[IS_COUNT][LT_COUNT] = {
385 /* IS_OUTSIDE */
386 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Eendif,
387 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eendif,
388 print, done, abort },
389 /* IS_FALSE_PREFIX */
390 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Strue, Sfalse,Selse, Dendif,
391 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Mpass, Eioccc,Eioccc,Eioccc,Eioccc,
392 drop, Eeof, abort },
393 /* IS_TRUE_PREFIX */
394 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Dfalse,Dfalse,Dfalse,Delse, Dendif,
395 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
396 print, Eeof, abort },
397 /* IS_PASS_MIDDLE */
398 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Pelif, Mtrue, Delif, Pelse, Pendif,
399 Oiffy, Oiffy, Fpass, Oif, Oif, Pelif, Oelif, Oelif, Pelse, Pendif,
400 print, Eeof, abort },
401 /* IS_FALSE_MIDDLE */
402 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Pelif, Mtrue, Delif, Pelse, Pendif,
403 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eioccc,Eioccc,Eioccc,Eioccc,Eioccc,
404 drop, Eeof, abort },
405 /* IS_TRUE_MIDDLE */
406 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Melif, Melif, Melif, Melse, Pendif,
407 Oiffy, Oiffy, Fpass, Oif, Oif, Eioccc,Eioccc,Eioccc,Eioccc,Pendif,
408 print, Eeof, abort },
409 /* IS_PASS_ELSE */
410 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Pendif,
411 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Pendif,
412 print, Eeof, abort },
413 /* IS_FALSE_ELSE */
414 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Dendif,
415 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Eelif, Eelif, Eelif, Eelse, Eioccc,
416 drop, Eeof, abort },
417 /* IS_TRUE_ELSE */
418 { Itrue, Ifalse,Fpass, Ftrue, Ffalse,Eelif, Eelif, Eelif, Eelse, Dendif,
419 Oiffy, Oiffy, Fpass, Oif, Oif, Eelif, Eelif, Eelif, Eelse, Eioccc,
420 print, Eeof, abort },
421 /* IS_FALSE_TRAILER */
422 { Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Dendif,
423 Idrop, Idrop, Fdrop, Fdrop, Fdrop, Dfalse,Dfalse,Dfalse,Delse, Eioccc,
424 drop, Eeof, abort }
425 /*TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF
426 TRUEI FALSEI IF TRUE FALSE ELIF ELTRUE ELFALSE ELSE ENDIF (DODGY)
427 PLAIN EOF ERROR */
428 };
429
430 /*
431 * State machine utility functions
432 */
433 static void
434 done(void)
435 {
436 if (incomment)
437 error("EOF in comment");
438 exit(exitstat);
439 }
440 static void
441 ignoreoff(void)
442 {
443 if (depth == 0)
444 abort(); /* bug */
445 ignoring[depth] = ignoring[depth-1];
446 }
447 static void
448 ignoreon(void)
449 {
450 ignoring[depth] = true;
451 }
452 static void
453 keywordedit(const char *replacement)
454 {
455 size_t size = tline + sizeof(tline) - keyword;
456 char *dst = keyword;
457 const char *src = replacement;
458 if (size != 0) {
459 while ((--size != 0) && (*src != '\0'))
460 *dst++ = *src++;
461 *dst = '\0';
462 }
463 print();
464 }
465 static void
466 nest(void)
467 {
468 if (depth > MAXDEPTH-1)
469 abort(); /* bug */
470 if (depth == MAXDEPTH-1)
471 error("Too many levels of nesting");
472 depth += 1;
473 stifline[depth] = linenum;
474 }
475 static void
476 unnest(void)
477 {
478 if (depth == 0)
479 abort(); /* bug */
480 depth -= 1;
481 }
482 static void
483 state(Ifstate is)
484 {
485 ifstate[depth] = is;
486 }
487
488 /*
489 * Write a line to the output or not, according to command line options.
490 */
491 static void
492 flushline(bool keep)
493 {
494 if (symlist)
495 return;
496 if (keep ^ complement) {
497 bool blankline = tline[strspn(tline, " \t\n")] == '\0';
498 if (blankline && compblank && blankcount != blankmax) {
499 delcount += 1;
500 blankcount += 1;
501 } else {
502 if (lnnum && delcount > 0)
503 printf("#line %d\n", linenum);
504 fputs(tline, stdout);
505 delcount = 0;
506 blankmax = blankcount = blankline ? blankcount + 1 : 0;
507 }
508 } else {
509 if (lnblank)
510 putc('\n', stdout);
511 exitstat = 1;
512 delcount += 1;
513 blankcount = 0;
514 }
515 }
516
517 /*
518 * The driver for the state machine.
519 */
520 static void
521 process(void)
522 {
523 Linetype lineval;
524
525 /* When compressing blank lines, act as if the file
526 is preceded by a large number of blank lines. */
527 blankmax = blankcount = 1000;
528 for (;;) {
529 linenum++;
530 lineval = parseline();
531 trans_table[ifstate[depth]][lineval]();
532 debug("process %s -> %s depth %d",
533 linetype_name[lineval],
534 ifstate_name[ifstate[depth]], depth);
535 }
536 }
537
538 /*
539 * Parse a line and determine its type. We keep the preprocessor line
540 * parser state between calls in the global variable linestate, with
541 * help from skipcomment().
542 */
543 static Linetype
544 parseline(void)
545 {
546 const char *cp;
547 int cursym;
548 int kwlen;
549 Linetype retval;
550 Comment_state wascomment;
551
552 if (fgets(tline, MAXLINE, input) == NULL)
553 return (LT_EOF);
554 retval = LT_PLAIN;
555 wascomment = incomment;
556 cp = skipcomment(tline);
557 if (linestate == LS_START) {
558 if (*cp == '#') {
559 linestate = LS_HASH;
560 cp = skipcomment(cp + 1);
561 } else if (*cp != '\0')
562 linestate = LS_DIRTY;
563 }
564 if (!incomment && linestate == LS_HASH) {
565 keyword = tline + (cp - tline);
566 cp = skipsym(cp);
567 kwlen = cp - keyword;
568 /* no way can we deal with a continuation inside a keyword */
569 if (strncmp(cp, "\\\n", 2) == 0)
570 Eioccc();
571 if (strlcmp("ifdef", keyword, kwlen) == 0 ||
572 strlcmp("ifndef", keyword, kwlen) == 0) {
573 cp = skipcomment(cp);
574 if ((cursym = findsym(cp)) < 0)
575 retval = LT_IF;
576 else {
577 retval = (keyword[2] == 'n')
578 ? LT_FALSE : LT_TRUE;
579 if (value[cursym] == NULL)
580 retval = (retval == LT_TRUE)
581 ? LT_FALSE : LT_TRUE;
582 if (ignore[cursym])
583 retval = (retval == LT_TRUE)
584 ? LT_TRUEI : LT_FALSEI;
585 }
586 cp = skipsym(cp);
587 } else if (strlcmp("if", keyword, kwlen) == 0)
588 retval = ifeval(&cp);
589 else if (strlcmp("elif", keyword, kwlen) == 0)
590 retval = ifeval(&cp) - LT_IF + LT_ELIF;
591 else if (strlcmp("else", keyword, kwlen) == 0)
592 retval = LT_ELSE;
593 else if (strlcmp("endif", keyword, kwlen) == 0)
594 retval = LT_ENDIF;
595 else {
596 linestate = LS_DIRTY;
597 retval = LT_PLAIN;
598 }
599 cp = skipcomment(cp);
600 if (*cp != '\0') {
601 linestate = LS_DIRTY;
602 if (retval == LT_TRUE || retval == LT_FALSE ||
603 retval == LT_TRUEI || retval == LT_FALSEI)
604 retval = LT_IF;
605 if (retval == LT_ELTRUE || retval == LT_ELFALSE)
606 retval = LT_ELIF;
607 }
608 if (retval != LT_PLAIN && (wascomment || incomment)) {
609 retval += LT_DODGY;
610 if (incomment)
611 linestate = LS_DIRTY;
612 }
613 /* skipcomment normally changes the state, except
614 if the last line of the file lacks a newline, or
615 if there is too much whitespace in a directive */
616 if (linestate == LS_HASH) {
617 size_t len = cp - tline;
618 if (fgets(tline + len, MAXLINE - len, input) == NULL) {
619 /* append the missing newline */
620 tline[len+0] = '\n';
621 tline[len+1] = '\0';
622 cp++;
623 linestate = LS_START;
624 } else {
625 linestate = LS_DIRTY;
626 }
627 }
628 }
629 if (linestate == LS_DIRTY) {
630 while (*cp != '\0')
631 cp = skipcomment(cp + 1);
632 }
633 debug("parser %s comment %s line",
634 comment_name[incomment], linestate_name[linestate]);
635 return (retval);
636 }
637
638 /*
639 * These are the binary operators that are supported by the expression
640 * evaluator.
641 */
642 static Linetype op_strict(int *p, int v, Linetype at, Linetype bt) {
643 if(at == LT_IF || bt == LT_IF) return (LT_IF);
644 return (*p = v, v ? LT_TRUE : LT_FALSE);
645 }
646 static Linetype op_lt(int *p, Linetype at, int a, Linetype bt, int b) {
647 return op_strict(p, a < b, at, bt);
648 }
649 static Linetype op_gt(int *p, Linetype at, int a, Linetype bt, int b) {
650 return op_strict(p, a > b, at, bt);
651 }
652 static Linetype op_le(int *p, Linetype at, int a, Linetype bt, int b) {
653 return op_strict(p, a <= b, at, bt);
654 }
655 static Linetype op_ge(int *p, Linetype at, int a, Linetype bt, int b) {
656 return op_strict(p, a >= b, at, bt);
657 }
658 static Linetype op_eq(int *p, Linetype at, int a, Linetype bt, int b) {
659 return op_strict(p, a == b, at, bt);
660 }
661 static Linetype op_ne(int *p, Linetype at, int a, Linetype bt, int b) {
662 return op_strict(p, a != b, at, bt);
663 }
664 static Linetype op_or(int *p, Linetype at, int a, Linetype bt, int b) {
665 if (!strictlogic && (at == LT_TRUE || bt == LT_TRUE))
666 return (*p = 1, LT_TRUE);
667 return op_strict(p, a || b, at, bt);
668 }
669 static Linetype op_and(int *p, Linetype at, int a, Linetype bt, int b) {
670 if (!strictlogic && (at == LT_FALSE || bt == LT_FALSE))
671 return (*p = 0, LT_FALSE);
672 return op_strict(p, a && b, at, bt);
673 }
674
675 /*
676 * An evaluation function takes three arguments, as follows: (1) a pointer to
677 * an element of the precedence table which lists the operators at the current
678 * level of precedence; (2) a pointer to an integer which will receive the
679 * value of the expression; and (3) a pointer to a char* that points to the
680 * expression to be evaluated and that is updated to the end of the expression
681 * when evaluation is complete. The function returns LT_FALSE if the value of
682 * the expression is zero, LT_TRUE if it is non-zero, LT_IF if the expression
683 * depends on an unknown symbol, or LT_ERROR if there is a parse failure.
684 */
685 struct ops;
686
687 typedef Linetype eval_fn(const struct ops *, int *, const char **);
688
689 static eval_fn eval_table, eval_unary;
690
691 /*
692 * The precedence table. Expressions involving binary operators are evaluated
693 * in a table-driven way by eval_table. When it evaluates a subexpression it
694 * calls the inner function with its first argument pointing to the next
695 * element of the table. Innermost expressions have special non-table-driven
696 * handling.
697 */
698 static const struct ops {
699 eval_fn *inner;
700 struct op {
701 const char *str;
702 Linetype (*fn)(int *, Linetype, int, Linetype, int);
703 } op[5];
704 } eval_ops[] = {
705 { eval_table, { { "||", op_or } } },
706 { eval_table, { { "&&", op_and } } },
707 { eval_table, { { "==", op_eq },
708 { "!=", op_ne } } },
709 { eval_unary, { { "<=", op_le },
710 { ">=", op_ge },
711 { "<", op_lt },
712 { ">", op_gt } } }
713 };
714
715 /*
716 * Function for evaluating the innermost parts of expressions,
717 * viz. !expr (expr) number defined(symbol) symbol
718 * We reset the constexpr flag in the last two cases.
719 */
720 static Linetype
721 eval_unary(const struct ops *ops, int *valp, const char **cpp)
722 {
723 const char *cp;
724 char *ep;
725 int sym;
726 bool defparen;
727 Linetype lt;
728
729 cp = skipcomment(*cpp);
730 if (*cp == '!') {
731 debug("eval%d !", ops - eval_ops);
732 cp++;
733 lt = eval_unary(ops, valp, &cp);
734 if (lt == LT_ERROR)
735 return (LT_ERROR);
736 if (lt != LT_IF) {
737 *valp = !*valp;
738 lt = *valp ? LT_TRUE : LT_FALSE;
739 }
740 } else if (*cp == '(') {
741 cp++;
742 debug("eval%d (", ops - eval_ops);
743 lt = eval_table(eval_ops, valp, &cp);
744 if (lt == LT_ERROR)
745 return (LT_ERROR);
746 cp = skipcomment(cp);
747 if (*cp++ != ')')
748 return (LT_ERROR);
749 } else if (isdigit((unsigned char)*cp)) {
750 debug("eval%d number", ops - eval_ops);
751 *valp = strtol(cp, &ep, 0);
752 if (ep == cp)
753 return (LT_ERROR);
754 lt = *valp ? LT_TRUE : LT_FALSE;
755 cp = skipsym(cp);
756 } else if (strncmp(cp, "defined", 7) == 0 && endsym(cp[7])) {
757 cp = skipcomment(cp+7);
758 debug("eval%d defined", ops - eval_ops);
759 if (*cp == '(') {
760 cp = skipcomment(cp+1);
761 defparen = true;
762 } else {
763 defparen = false;
764 }
765 sym = findsym(cp);
766 if (sym < 0) {
767 lt = LT_IF;
768 } else {
769 *valp = (value[sym] != NULL);
770 lt = *valp ? LT_TRUE : LT_FALSE;
771 }
772 cp = skipsym(cp);
773 cp = skipcomment(cp);
774 if (defparen && *cp++ != ')')
775 return (LT_ERROR);
776 constexpr = false;
777 } else if (!endsym(*cp)) {
778 debug("eval%d symbol", ops - eval_ops);
779 sym = findsym(cp);
780 cp = skipsym(cp);
781 if (sym < 0) {
782 lt = LT_IF;
783 cp = skipargs(cp);
784 } else if (value[sym] == NULL) {
785 *valp = 0;
786 lt = LT_FALSE;
787 } else {
788 *valp = strtol(value[sym], &ep, 0);
789 if (*ep != '\0' || ep == value[sym])
790 return (LT_ERROR);
791 lt = *valp ? LT_TRUE : LT_FALSE;
792 cp = skipargs(cp);
793 }
794 constexpr = false;
795 } else {
796 debug("eval%d bad expr", ops - eval_ops);
797 return (LT_ERROR);
798 }
799
800 *cpp = cp;
801 debug("eval%d = %d", ops - eval_ops, *valp);
802 return (lt);
803 }
804
805 /*
806 * Table-driven evaluation of binary operators.
807 */
808 static Linetype
809 eval_table(const struct ops *ops, int *valp, const char **cpp)
810 {
811 const struct op *op;
812 const char *cp;
813 int val;
814 Linetype lt, rt;
815
816 debug("eval%d", ops - eval_ops);
817 cp = *cpp;
818 lt = ops->inner(ops+1, valp, &cp);
819 if (lt == LT_ERROR)
820 return (LT_ERROR);
821 for (;;) {
822 cp = skipcomment(cp);
823 for (op = ops->op; op->str != NULL; op++)
824 if (strncmp(cp, op->str, strlen(op->str)) == 0)
825 break;
826 if (op->str == NULL)
827 break;
828 cp += strlen(op->str);
829 debug("eval%d %s", ops - eval_ops, op->str);
830 rt = ops->inner(ops+1, &val, &cp);
831 if (rt == LT_ERROR)
832 return (LT_ERROR);
833 lt = op->fn(valp, lt, *valp, rt, val);
834 }
835
836 *cpp = cp;
837 debug("eval%d = %d", ops - eval_ops, *valp);
838 debug("eval%d lt = %s", ops - eval_ops, linetype_name[lt]);
839 return (lt);
840 }
841
842 /*
843 * Evaluate the expression on a #if or #elif line. If we can work out
844 * the result we return LT_TRUE or LT_FALSE accordingly, otherwise we
845 * return just a generic LT_IF.
846 */
847 static Linetype
848 ifeval(const char **cpp)
849 {
850 int ret;
851 int val = 0;
852
853 debug("eval %s", *cpp);
854 constexpr = killconsts ? false : true;
855 ret = eval_table(eval_ops, &val, cpp);
856 debug("eval = %d", val);
857 return (constexpr ? LT_IF : ret == LT_ERROR ? LT_IF : ret);
858 }
859
860 /*
861 * Skip over comments, strings, and character literals and stop at the
862 * next character position that is not whitespace. Between calls we keep
863 * the comment state in the global variable incomment, and we also adjust
864 * the global variable linestate when we see a newline.
865 * XXX: doesn't cope with the buffer splitting inside a state transition.
866 */
867 static const char *
868 skipcomment(const char *cp)
869 {
870 if (text || ignoring[depth]) {
871 for (; isspace((unsigned char)*cp); cp++)
872 if (*cp == '\n')
873 linestate = LS_START;
874 return (cp);
875 }
876 while (*cp != '\0')
877 /* don't reset to LS_START after a line continuation */
878 if (strncmp(cp, "\\\n", 2) == 0)
879 cp += 2;
880 else switch (incomment) {
881 case NO_COMMENT:
882 if (strncmp(cp, "/\\\n", 3) == 0) {
883 incomment = STARTING_COMMENT;
884 cp += 3;
885 } else if (strncmp(cp, "/*", 2) == 0) {
886 incomment = C_COMMENT;
887 cp += 2;
888 } else if (strncmp(cp, "//", 2) == 0) {
889 incomment = CXX_COMMENT;
890 cp += 2;
891 } else if (strncmp(cp, "\'", 1) == 0) {
892 incomment = CHAR_LITERAL;
893 linestate = LS_DIRTY;
894 cp += 1;
895 } else if (strncmp(cp, "\"", 1) == 0) {
896 incomment = STRING_LITERAL;
897 linestate = LS_DIRTY;
898 cp += 1;
899 } else if (strncmp(cp, "\n", 1) == 0) {
900 linestate = LS_START;
901 cp += 1;
902 } else if (strchr(" \t", *cp) != NULL) {
903 cp += 1;
904 } else
905 return (cp);
906 continue;
907 case CXX_COMMENT:
908 if (strncmp(cp, "\n", 1) == 0) {
909 incomment = NO_COMMENT;
910 linestate = LS_START;
911 }
912 cp += 1;
913 continue;
914 case CHAR_LITERAL:
915 case STRING_LITERAL:
916 if ((incomment == CHAR_LITERAL && cp[0] == '\'') ||
917 (incomment == STRING_LITERAL && cp[0] == '\"')) {
918 incomment = NO_COMMENT;
919 cp += 1;
920 } else if (cp[0] == '\\') {
921 if (cp[1] == '\0')
922 cp += 1;
923 else
924 cp += 2;
925 } else if (strncmp(cp, "\n", 1) == 0) {
926 if (incomment == CHAR_LITERAL)
927 error("unterminated char literal");
928 else
929 error("unterminated string literal");
930 } else
931 cp += 1;
932 continue;
933 case C_COMMENT:
934 if (strncmp(cp, "*\\\n", 3) == 0) {
935 incomment = FINISHING_COMMENT;
936 cp += 3;
937 } else if (strncmp(cp, "*/", 2) == 0) {
938 incomment = NO_COMMENT;
939 cp += 2;
940 } else
941 cp += 1;
942 continue;
943 case STARTING_COMMENT:
944 if (*cp == '*') {
945 incomment = C_COMMENT;
946 cp += 1;
947 } else if (*cp == '/') {
948 incomment = CXX_COMMENT;
949 cp += 1;
950 } else {
951 incomment = NO_COMMENT;
952 linestate = LS_DIRTY;
953 }
954 continue;
955 case FINISHING_COMMENT:
956 if (*cp == '/') {
957 incomment = NO_COMMENT;
958 cp += 1;
959 } else
960 incomment = C_COMMENT;
961 continue;
962 default:
963 abort(); /* bug */
964 }
965 return (cp);
966 }
967
968 /*
969 * Skip macro arguments.
970 */
971 static const char *
972 skipargs(const char *cp)
973 {
974 const char *ocp = cp;
975 int level = 0;
976 cp = skipcomment(cp);
977 if (*cp != '(')
978 return (cp);
979 do {
980 if (*cp == '(')
981 level++;
982 if (*cp == ')')
983 level--;
984 cp = skipcomment(cp+1);
985 } while (level != 0 && *cp != '\0');
986 if (level == 0)
987 return (cp);
988 else
989 /* Rewind and re-detect the syntax error later. */
990 return (ocp);
991 }
992
993 /*
994 * Skip over an identifier.
995 */
996 static const char *
997 skipsym(const char *cp)
998 {
999 while (!endsym(*cp))
1000 ++cp;
1001 return (cp);
1002 }
1003
1004 /*
1005 * Look for the symbol in the symbol table. If it is found, we return
1006 * the symbol table index, else we return -1.
1007 */
1008 static int
1009 findsym(const char *str)
1010 {
1011 const char *cp;
1012 int symind;
1013
1014 cp = skipsym(str);
1015 if (cp == str)
1016 return (-1);
1017 if (symlist) {
1018 printf("%.*s\n", (int)(cp-str), str);
1019 /* we don't care about the value of the symbol */
1020 return (0);
1021 }
1022 for (symind = 0; symind < nsyms; ++symind) {
1023 if (strlcmp(symname[symind], str, cp-str) == 0) {
1024 debug("findsym %s %s", symname[symind],
1025 value[symind] ? value[symind] : "");
1026 return (symind);
1027 }
1028 }
1029 return (-1);
1030 }
1031
1032 /*
1033 * Add a symbol to the symbol table.
1034 */
1035 static void
1036 addsym(bool ignorethis, bool definethis, char *sym)
1037 {
1038 int symind;
1039 char *val;
1040
1041 symind = findsym(sym);
1042 if (symind < 0) {
1043 if (nsyms >= MAXSYMS)
1044 errx(2, "too many symbols");
1045 symind = nsyms++;
1046 }
1047 symname[symind] = sym;
1048 ignore[symind] = ignorethis;
1049 val = sym + (skipsym(sym) - sym);
1050 if (definethis) {
1051 if (*val == '=') {
1052 value[symind] = val+1;
1053 *val = '\0';
1054 } else if (*val == '\0')
1055 value[symind] = "";
1056 else
1057 usage();
1058 } else {
1059 if (*val != '\0')
1060 usage();
1061 value[symind] = NULL;
1062 }
1063 }
1064
1065 /*
1066 * Compare s with n characters of t.
1067 * The same as strncmp() except that it checks that s[n] == '\0'.
1068 */
1069 static int
1070 strlcmp(const char *s, const char *t, size_t n)
1071 {
1072 while (n-- && *t != '\0')
1073 if (*s != *t)
1074 return ((unsigned char)*s - (unsigned char)*t);
1075 else
1076 ++s, ++t;
1077 return ((unsigned char)*s);
1078 }
1079
1080 /*
1081 * Diagnostics.
1082 */
1083 static void
1084 debug(const char *msg, ...)
1085 {
1086 va_list ap;
1087
1088 if (debugging) {
1089 va_start(ap, msg);
1090 vwarnx(msg, ap);
1091 va_end(ap);
1092 }
1093 }
1094
1095 static void
1096 error(const char *msg)
1097 {
1098 if (depth == 0)
1099 warnx("%s: %d: %s", filename, linenum, msg);
1100 else
1101 warnx("%s: %d: %s (#if line %d depth %d)",
1102 filename, linenum, msg, stifline[depth], depth);
1103 errx(2, "output may be truncated");
1104 }
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