aboutsummaryrefslogtreecommitdiff
path: root/libcpp/init.c
blob: cfc16e8f8d4ef9da57caa4073722afa46fd06a65 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
/* CPP Library.
   Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008,
   2009, 2010 Free Software Foundation, Inc.
   Contributed by Per Bothner, 1994-95.
   Based on CCCP program by Paul Rubin, June 1986
   Adapted to ANSI C, Richard Stallman, Jan 1987

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "cpplib.h"
#include "internal.h"
#include "mkdeps.h"
#include "localedir.h"

static void init_library (void);
static void mark_named_operators (cpp_reader *, int);
static void read_original_filename (cpp_reader *);
static void read_original_directory (cpp_reader *);
static void post_options (cpp_reader *);

/* If we have designated initializers (GCC >2.7) these tables can be
   initialized, constant data.  Otherwise, they have to be filled in at
   runtime.  */
#if HAVE_DESIGNATED_INITIALIZERS

#define init_trigraph_map()  /* Nothing.  */
#define TRIGRAPH_MAP \
__extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {

#define END };
#define s(p, v) [p] = v,

#else

#define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
 static void init_trigraph_map (void) { \
 unsigned char *x = _cpp_trigraph_map;

#define END }
#define s(p, v) x[p] = v;

#endif

TRIGRAPH_MAP
  s('=', '#')	s(')', ']')	s('!', '|')
  s('(', '[')	s('\'', '^')	s('>', '}')
  s('/', '\\')	s('<', '{')	s('-', '~')
END

#undef s
#undef END
#undef TRIGRAPH_MAP

/* A set of booleans indicating what CPP features each source language
   requires.  */
struct lang_flags
{
  char c99;
  char cplusplus;
  char extended_numbers;
  char extended_identifiers;
  char std;
  char cplusplus_comments;
  char digraphs;
  char uliterals;
};

static const struct lang_flags lang_defaults[] =
{ /*              c99 c++ xnum xid std  //   digr ulit */
  /* GNUC89   */  { 0,  0,  1,   0,  0,   1,   1,   0 },
  /* GNUC99   */  { 1,  0,  1,   0,  0,   1,   1,   1 },
  /* GNUC1X   */  { 1,  0,  1,   0,  0,   1,   1,   1 },
  /* STDC89   */  { 0,  0,  0,   0,  1,   0,   0,   0 },
  /* STDC94   */  { 0,  0,  0,   0,  1,   0,   1,   0 },
  /* STDC99   */  { 1,  0,  1,   0,  1,   1,   1,   0 },
  /* STDC1X   */  { 1,  0,  1,   0,  1,   1,   1,   0 },
  /* GNUCXX   */  { 0,  1,  1,   0,  0,   1,   1,   0 },
  /* CXX98    */  { 0,  1,  1,   0,  1,   1,   1,   0 },
  /* GNUCXX0X */  { 1,  1,  1,   0,  0,   1,   1,   1 },
  /* CXX0X    */  { 1,  1,  1,   0,  1,   1,   1,   1 },
  /* ASM      */  { 0,  0,  1,   0,  0,   1,   0,   0 }
  /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX0X, and
     CXX0X when no longer experimental (when all uses of identifiers
     in the compiler have been audited for correct handling of
     extended identifiers).  */
};

/* Sets internal flags correctly for a given language.  */
void
cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
{
  const struct lang_flags *l = &lang_defaults[(int) lang];

  CPP_OPTION (pfile, lang) = lang;

  CPP_OPTION (pfile, c99)			 = l->c99;
  CPP_OPTION (pfile, cplusplus)			 = l->cplusplus;
  CPP_OPTION (pfile, extended_numbers)		 = l->extended_numbers;
  CPP_OPTION (pfile, extended_identifiers)	 = l->extended_identifiers;
  CPP_OPTION (pfile, std)			 = l->std;
  CPP_OPTION (pfile, trigraphs)			 = l->std;
  CPP_OPTION (pfile, cplusplus_comments)	 = l->cplusplus_comments;
  CPP_OPTION (pfile, digraphs)			 = l->digraphs;
  CPP_OPTION (pfile, uliterals)			 = l->uliterals;
}

/* Initialize library global state.  */
static void
init_library (void)
{
  static int initialized = 0;

  if (! initialized)
    {
      initialized = 1;

      /* Set up the trigraph map.  This doesn't need to do anything if
	 we were compiled with a compiler that supports C99 designated
	 initializers.  */
      init_trigraph_map ();

#ifdef ENABLE_NLS
       (void) bindtextdomain (PACKAGE, LOCALEDIR);
#endif
    }
}

/* Initialize a cpp_reader structure.  */
cpp_reader *
cpp_create_reader (enum c_lang lang, hash_table *table,
		   struct line_maps *line_table)
{
  cpp_reader *pfile;

  /* Initialize this instance of the library if it hasn't been already.  */
  init_library ();

  pfile = XCNEW (cpp_reader);

  cpp_set_lang (pfile, lang);
  CPP_OPTION (pfile, warn_multichar) = 1;
  CPP_OPTION (pfile, discard_comments) = 1;
  CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
  CPP_OPTION (pfile, tabstop) = 8;
  CPP_OPTION (pfile, operator_names) = 1;
  CPP_OPTION (pfile, warn_trigraphs) = 2;
  CPP_OPTION (pfile, warn_endif_labels) = 1;
  CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
  CPP_OPTION (pfile, cpp_warn_long_long) = 0;
  CPP_OPTION (pfile, dollars_in_ident) = 1;
  CPP_OPTION (pfile, warn_dollars) = 1;
  CPP_OPTION (pfile, warn_variadic_macros) = 1;
  CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
  CPP_OPTION (pfile, warn_normalize) = normalized_C;

  /* Default CPP arithmetic to something sensible for the host for the
     benefit of dumb users like fix-header.  */
  CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
  CPP_OPTION (pfile, char_precision) = CHAR_BIT;
  CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
  CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
  CPP_OPTION (pfile, unsigned_char) = 0;
  CPP_OPTION (pfile, unsigned_wchar) = 1;
  CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */

  /* Default to no charset conversion.  */
  CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
  CPP_OPTION (pfile, wide_charset) = 0;

  /* Default the input character set to UTF-8.  */
  CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();

  /* A fake empty "directory" used as the starting point for files
     looked up without a search path.  Name cannot be '/' because we
     don't want to prepend anything at all to filenames using it.  All
     other entries are correct zero-initialized.  */
  pfile->no_search_path.name = (char *) "";

  /* Initialize the line map.  */
  pfile->line_table = line_table;

  /* Initialize lexer state.  */
  pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);

  /* Set up static tokens.  */
  pfile->avoid_paste.type = CPP_PADDING;
  pfile->avoid_paste.val.source = NULL;
  pfile->eof.type = CPP_EOF;
  pfile->eof.flags = 0;

  /* Create a token buffer for the lexer.  */
  _cpp_init_tokenrun (&pfile->base_run, 250);
  pfile->cur_run = &pfile->base_run;
  pfile->cur_token = pfile->base_run.base;

  /* Initialize the base context.  */
  pfile->context = &pfile->base_context;
  pfile->base_context.macro = 0;
  pfile->base_context.prev = pfile->base_context.next = 0;

  /* Aligned and unaligned storage.  */
  pfile->a_buff = _cpp_get_buff (pfile, 0);
  pfile->u_buff = _cpp_get_buff (pfile, 0);

  /* Initialize table for push_macro/pop_macro.  */
  pfile->pushed_macros = 0;

  /* The expression parser stack.  */
  _cpp_expand_op_stack (pfile);

  /* Initialize the buffer obstack.  */
  _obstack_begin (&pfile->buffer_ob, 0, 0,
		  (void *(*) (long)) xmalloc,
		  (void (*) (void *)) free);

  _cpp_init_files (pfile);

  _cpp_init_hashtable (pfile, table);

  return pfile;
}

/* Set the line_table entry in PFILE.  This is called after reading a
   PCH file, as the old line_table will be incorrect.  */
void
cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
{
  pfile->line_table = line_table;
}

/* Free resources used by PFILE.  Accessing PFILE after this function
   returns leads to undefined behavior.  Returns the error count.  */
void
cpp_destroy (cpp_reader *pfile)
{
  cpp_context *context, *contextn;
  struct def_pragma_macro *pmacro;
  tokenrun *run, *runn;
  int i;

  free (pfile->op_stack);

  while (CPP_BUFFER (pfile) != NULL)
    _cpp_pop_buffer (pfile);

  if (pfile->out.base)
    free (pfile->out.base);

  if (pfile->macro_buffer)
    {
      free (pfile->macro_buffer);
      pfile->macro_buffer = NULL;
      pfile->macro_buffer_len = 0;
    }

  if (pfile->deps)
    deps_free (pfile->deps);
  obstack_free (&pfile->buffer_ob, 0);

  _cpp_destroy_hashtable (pfile);
  _cpp_cleanup_files (pfile);
  _cpp_destroy_iconv (pfile);

  _cpp_free_buff (pfile->a_buff);
  _cpp_free_buff (pfile->u_buff);
  _cpp_free_buff (pfile->free_buffs);

  for (run = &pfile->base_run; run; run = runn)
    {
      runn = run->next;
      free (run->base);
      if (run != &pfile->base_run)
	free (run);
    }

  for (context = pfile->base_context.next; context; context = contextn)
    {
      contextn = context->next;
      free (context);
    }

  if (pfile->comments.entries)
    {
      for (i = 0; i < pfile->comments.count; i++)
	free (pfile->comments.entries[i].comment);

      free (pfile->comments.entries);
    }
  if (pfile->pushed_macros)
    {
      do
	{
	  pmacro = pfile->pushed_macros;
	  pfile->pushed_macros = pmacro->next;
	  free (pmacro->name);
	  free (pmacro);
	}
      while (pfile->pushed_macros);
    }

  free (pfile);
}

/* This structure defines one built-in identifier.  A node will be
   entered in the hash table under the name NAME, with value VALUE.

   There are two tables of these.  builtin_array holds all the
   "builtin" macros: these are handled by builtin_macro() in
   macro.c.  Builtin is somewhat of a misnomer -- the property of
   interest is that these macros require special code to compute their
   expansions.  The value is a "cpp_builtin_type" enumerator.

   operator_array holds the C++ named operators.  These are keywords
   which act as aliases for punctuators.  In C++, they cannot be
   altered through #define, and #if recognizes them as operators.  In
   C, these are not entered into the hash table at all (but see
   <iso646.h>).  The value is a token-type enumerator.  */
struct builtin_macro
{
  const uchar *const name;
  const unsigned short len;
  const unsigned short value;
  const bool always_warn_if_redefined;
};

#define B(n, t, f)    { DSC(n), t, f }
static const struct builtin_macro builtin_array[] =
{
  B("__TIMESTAMP__",	 BT_TIMESTAMP,     false),
  B("__TIME__",		 BT_TIME,          false),
  B("__DATE__",		 BT_DATE,          false),
  B("__FILE__",		 BT_FILE,          false),
  B("__BASE_FILE__",	 BT_BASE_FILE,     false),
  B("__LINE__",		 BT_SPECLINE,      true),
  B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
  B("__COUNTER__",	 BT_COUNTER,       true),
  /* Keep builtins not used for -traditional-cpp at the end, and
     update init_builtins() if any more are added.  */
  B("_Pragma",		 BT_PRAGMA,        true),
  B("__STDC__",		 BT_STDC,          true),
};
#undef B

struct builtin_operator
{
  const uchar *const name;
  const unsigned short len;
  const unsigned short value;
};

#define B(n, t)    { DSC(n), t }
static const struct builtin_operator operator_array[] =
{
  B("and",	CPP_AND_AND),
  B("and_eq",	CPP_AND_EQ),
  B("bitand",	CPP_AND),
  B("bitor",	CPP_OR),
  B("compl",	CPP_COMPL),
  B("not",	CPP_NOT),
  B("not_eq",	CPP_NOT_EQ),
  B("or",	CPP_OR_OR),
  B("or_eq",	CPP_OR_EQ),
  B("xor",	CPP_XOR),
  B("xor_eq",	CPP_XOR_EQ)
};
#undef B

/* Mark the C++ named operators in the hash table.  */
static void
mark_named_operators (cpp_reader *pfile, int flags)
{
  const struct builtin_operator *b;

  for (b = operator_array;
       b < (operator_array + ARRAY_SIZE (operator_array));
       b++)
    {
      cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
      hp->flags |= flags;
      hp->is_directive = 0;
      hp->directive_index = b->value;
    }
}

/* Helper function of cpp_type2name. Return the string associated with
   named operator TYPE.  */
const char *
cpp_named_operator2name (enum cpp_ttype type)
{
  const struct builtin_operator *b;

  for (b = operator_array;
       b < (operator_array + ARRAY_SIZE (operator_array));
       b++)
    {
      if (type == b->value)
	return (const char *) b->name;
    }

  return NULL;
}

void
cpp_init_special_builtins (cpp_reader *pfile)
{
  const struct builtin_macro *b;
  size_t n = ARRAY_SIZE (builtin_array);

  if (CPP_OPTION (pfile, traditional))
    n -= 2;
  else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
	   || CPP_OPTION (pfile, std))
    n--;

  for (b = builtin_array; b < builtin_array + n; b++)
    {
      cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
      hp->type = NT_MACRO;
      hp->flags |= NODE_BUILTIN;
      if (b->always_warn_if_redefined
          || CPP_OPTION (pfile, warn_builtin_macro_redefined))
	hp->flags |= NODE_WARN;
      hp->value.builtin = (enum cpp_builtin_type) b->value;
    }
}

/* Read the builtins table above and enter them, and language-specific
   macros, into the hash table.  HOSTED is true if this is a hosted
   environment.  */
void
cpp_init_builtins (cpp_reader *pfile, int hosted)
{
  cpp_init_special_builtins (pfile);

  if (!CPP_OPTION (pfile, traditional)
      && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
	  || CPP_OPTION (pfile, std)))
    _cpp_define_builtin (pfile, "__STDC__ 1");

  if (CPP_OPTION (pfile, cplusplus))
    _cpp_define_builtin (pfile, "__cplusplus 1");
  else if (CPP_OPTION (pfile, lang) == CLK_ASM)
    _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
  else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
    _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
  else if (CPP_OPTION (pfile, lang) == CLK_STDC1X
	   || CPP_OPTION (pfile, lang) == CLK_GNUC1X)
    _cpp_define_builtin (pfile, "__STDC_VERSION__ 201000L");
  else if (CPP_OPTION (pfile, c99))
    _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");

  if (hosted)
    _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
  else
    _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");

  if (CPP_OPTION (pfile, objc))
    _cpp_define_builtin (pfile, "__OBJC__ 1");
}

/* Sanity-checks are dependent on command-line options, so it is
   called as a subroutine of cpp_read_main_file ().  */
#if ENABLE_CHECKING
static void sanity_checks (cpp_reader *);
static void sanity_checks (cpp_reader *pfile)
{
  cppchar_t test = 0;
  size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);

  /* Sanity checks for assumptions about CPP arithmetic and target
     type precisions made by cpplib.  */
  test--;
  if (test < 1)
    cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");

  if (CPP_OPTION (pfile, precision) > max_precision)
    cpp_error (pfile, CPP_DL_ICE,
	       "preprocessor arithmetic has maximum precision of %lu bits;"
	       " target requires %lu bits",
	       (unsigned long) max_precision,
	       (unsigned long) CPP_OPTION (pfile, precision));

  if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
    cpp_error (pfile, CPP_DL_ICE,
	       "CPP arithmetic must be at least as precise as a target int");

  if (CPP_OPTION (pfile, char_precision) < 8)
    cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");

  if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
    cpp_error (pfile, CPP_DL_ICE,
	       "target wchar_t is narrower than target char");

  if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
    cpp_error (pfile, CPP_DL_ICE,
	       "target int is narrower than target char");

  /* This is assumed in eval_token() and could be fixed if necessary.  */
  if (sizeof (cppchar_t) > sizeof (cpp_num_part))
    cpp_error (pfile, CPP_DL_ICE,
	       "CPP half-integer narrower than CPP character");

  if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
    cpp_error (pfile, CPP_DL_ICE,
	       "CPP on this host cannot handle wide character constants over"
	       " %lu bits, but the target requires %lu bits",
	       (unsigned long) BITS_PER_CPPCHAR_T,
	       (unsigned long) CPP_OPTION (pfile, wchar_precision));
}
#else
# define sanity_checks(PFILE)
#endif

/* This is called after options have been parsed, and partially
   processed.  */
void
cpp_post_options (cpp_reader *pfile)
{
  int flags;

  sanity_checks (pfile);

  post_options (pfile);

  /* Mark named operators before handling command line macros.  */
  flags = 0;
  if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
    flags |= NODE_OPERATOR;
  if (CPP_OPTION (pfile, warn_cxx_operator_names))
    flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
  if (flags != 0)
    mark_named_operators (pfile, flags);
}

/* Setup for processing input from the file named FNAME, or stdin if
   it is the empty string.  Return the original filename
   on success (e.g. foo.i->foo.c), or NULL on failure.  */
const char *
cpp_read_main_file (cpp_reader *pfile, const char *fname)
{
  if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
    {
      if (!pfile->deps)
	pfile->deps = deps_init ();

      /* Set the default target (if there is none already).  */
      deps_add_default_target (pfile->deps, fname);
    }

  pfile->main_file
    = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0);
  if (_cpp_find_failed (pfile->main_file))
    return NULL;

  _cpp_stack_file (pfile, pfile->main_file, false);

  /* For foo.i, read the original filename foo.c now, for the benefit
     of the front ends.  */
  if (CPP_OPTION (pfile, preprocessed))
    {
      read_original_filename (pfile);
      fname = pfile->line_table->maps[pfile->line_table->used-1].to_file;
    }
  return fname;
}

/* For preprocessed files, if the first tokens are of the form # NUM.
   handle the directive so we know the original file name.  This will
   generate file_change callbacks, which the front ends must handle
   appropriately given their state of initialization.  */
static void
read_original_filename (cpp_reader *pfile)
{
  const cpp_token *token, *token1;

  /* Lex ahead; if the first tokens are of the form # NUM, then
     process the directive, otherwise back up.  */
  token = _cpp_lex_direct (pfile);
  if (token->type == CPP_HASH)
    {
      pfile->state.in_directive = 1;
      token1 = _cpp_lex_direct (pfile);
      _cpp_backup_tokens (pfile, 1);
      pfile->state.in_directive = 0;

      /* If it's a #line directive, handle it.  */
      if (token1->type == CPP_NUMBER
	  && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
	{
	  read_original_directory (pfile);
	  return;
	}
    }

  /* Backup as if nothing happened.  */
  _cpp_backup_tokens (pfile, 1);
}

/* For preprocessed files, if the tokens following the first filename
   line is of the form # <line> "/path/name//", handle the
   directive so we know the original current directory.  */
static void
read_original_directory (cpp_reader *pfile)
{
  const cpp_token *hash, *token;

  /* Lex ahead; if the first tokens are of the form # NUM, then
     process the directive, otherwise back up.  */
  hash = _cpp_lex_direct (pfile);
  if (hash->type != CPP_HASH)
    {
      _cpp_backup_tokens (pfile, 1);
      return;
    }

  token = _cpp_lex_direct (pfile);

  if (token->type != CPP_NUMBER)
    {
      _cpp_backup_tokens (pfile, 2);
      return;
    }

  token = _cpp_lex_direct (pfile);

  if (token->type != CPP_STRING
      || ! (token->val.str.len >= 5
	    && token->val.str.text[token->val.str.len-2] == '/'
	    && token->val.str.text[token->val.str.len-3] == '/'))
    {
      _cpp_backup_tokens (pfile, 3);
      return;
    }

  if (pfile->cb.dir_change)
    {
      char *debugdir = (char *) alloca (token->val.str.len - 3);

      memcpy (debugdir, (const char *) token->val.str.text + 1,
	      token->val.str.len - 4);
      debugdir[token->val.str.len - 4] = '\0';

      pfile->cb.dir_change (pfile, debugdir);
    }      
}

/* This is called at the end of preprocessing.  It pops the last
   buffer and writes dependency output.

   Maybe it should also reset state, such that you could call
   cpp_start_read with a new filename to restart processing.  */
void
cpp_finish (cpp_reader *pfile, FILE *deps_stream)
{
  /* Warn about unused macros before popping the final buffer.  */
  if (CPP_OPTION (pfile, warn_unused_macros))
    cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);

  /* lex.c leaves the final buffer on the stack.  This it so that
     it returns an unending stream of CPP_EOFs to the client.  If we
     popped the buffer, we'd dereference a NULL buffer pointer and
     segfault.  It's nice to allow the client to do worry-free excess
     cpp_get_token calls.  */
  while (pfile->buffer)
    _cpp_pop_buffer (pfile);

  if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
      && deps_stream)
    {
      deps_write (pfile->deps, deps_stream, 72);

      if (CPP_OPTION (pfile, deps.phony_targets))
	deps_phony_targets (pfile->deps, deps_stream);
    }

  /* Report on headers that could use multiple include guards.  */
  if (CPP_OPTION (pfile, print_include_names))
    _cpp_report_missing_guards (pfile);
}

static void
post_options (cpp_reader *pfile)
{
  /* -Wtraditional is not useful in C++ mode.  */
  if (CPP_OPTION (pfile, cplusplus))
    CPP_OPTION (pfile, cpp_warn_traditional) = 0;

  /* Permanently disable macro expansion if we are rescanning
     preprocessed text.  Read preprocesed source in ISO mode.  */
  if (CPP_OPTION (pfile, preprocessed))
    {
      if (!CPP_OPTION (pfile, directives_only))
	pfile->state.prevent_expansion = 1;
      CPP_OPTION (pfile, traditional) = 0;
    }

  if (CPP_OPTION (pfile, warn_trigraphs) == 2)
    CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);

  if (CPP_OPTION (pfile, traditional))
    {
      CPP_OPTION (pfile, cplusplus_comments) = 0;

      CPP_OPTION (pfile, trigraphs) = 0;
      CPP_OPTION (pfile, warn_trigraphs) = 0;
    }
}