aboutsummaryrefslogtreecommitdiff
path: root/gcc/c-lex.c
blob: 1c832c50d15a648979fbedb5864d82eb4a73f1e4 (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
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
/* Mainly the interface between cpplib and the C front ends.
   Copyright (C) 1987, 1988, 1989, 1992, 1994, 1995, 1996, 1997
   1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   Free Software Foundation, Inc.

This file is part of GCC.

GCC 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 2, or (at your option) any later
version.

GCC 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 GCC; see the file COPYING.  If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"

#include "real.h"
#include "rtl.h"
#include "tree.h"
#include "input.h"
#include "output.h"
#include "c-tree.h"
#include "c-common.h"
#include "flags.h"
#include "timevar.h"
#include "cpplib.h"
#include "c-pragma.h"
#include "toplev.h"
#include "intl.h"
#include "tm_p.h"
#include "splay-tree.h"
#include "debug.h"

/* We may keep statistics about how long which files took to compile.  */
static int header_time, body_time;
static splay_tree file_info_tree;

int pending_lang_change; /* If we need to switch languages - C++ only */
int c_header_level;	 /* depth in C headers - C++ only */

/* If we need to translate characters received.  This is tri-state:
   0 means use only the untranslated string; 1 means use only
   the translated string; -1 means chain the translated string
   to the untranslated one.  */
int c_lex_string_translate = 1;

/* True if strings should be passed to the caller of c_lex completely
   unmolested (no concatenation, no translation).  */
bool c_lex_return_raw_strings = false;

static tree interpret_integer (const cpp_token *, unsigned int);
static tree interpret_float (const cpp_token *, unsigned int);
static enum integer_type_kind narrowest_unsigned_type
	(unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT, unsigned int);
static enum integer_type_kind narrowest_signed_type
	(unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT, unsigned int);
static enum cpp_ttype lex_string (const cpp_token *, tree *, bool);
static tree lex_charconst (const cpp_token *);
static void update_header_times (const char *);
static int dump_one_header (splay_tree_node, void *);
static void cb_line_change (cpp_reader *, const cpp_token *, int);
static void cb_ident (cpp_reader *, unsigned int, const cpp_string *);
static void cb_def_pragma (cpp_reader *, unsigned int);
static void cb_define (cpp_reader *, unsigned int, cpp_hashnode *);
static void cb_undef (cpp_reader *, unsigned int, cpp_hashnode *);

void
init_c_lex (void)
{
  struct cpp_callbacks *cb;
  struct c_fileinfo *toplevel;

  /* The get_fileinfo data structure must be initialized before
     cpp_read_main_file is called.  */
  toplevel = get_fileinfo ("<top level>");
  if (flag_detailed_statistics)
    {
      header_time = 0;
      body_time = get_run_time ();
      toplevel->time = body_time;
    }

  cb = cpp_get_callbacks (parse_in);

  cb->line_change = cb_line_change;
  cb->ident = cb_ident;
  cb->def_pragma = cb_def_pragma;
  cb->valid_pch = c_common_valid_pch;
  cb->read_pch = c_common_read_pch;

  /* Set the debug callbacks if we can use them.  */
  if (debug_info_level == DINFO_LEVEL_VERBOSE
      && (write_symbols == DWARF2_DEBUG
          || write_symbols == VMS_AND_DWARF2_DEBUG))
    {
      cb->define = cb_define;
      cb->undef = cb_undef;
    }
}

struct c_fileinfo *
get_fileinfo (const char *name)
{
  splay_tree_node n;
  struct c_fileinfo *fi;

  if (!file_info_tree)
    file_info_tree = splay_tree_new ((splay_tree_compare_fn) strcmp,
				     0,
				     (splay_tree_delete_value_fn) free);

  n = splay_tree_lookup (file_info_tree, (splay_tree_key) name);
  if (n)
    return (struct c_fileinfo *) n->value;

  fi = XNEW (struct c_fileinfo);
  fi->time = 0;
  fi->interface_only = 0;
  fi->interface_unknown = 1;
  splay_tree_insert (file_info_tree, (splay_tree_key) name,
		     (splay_tree_value) fi);
  return fi;
}

static void
update_header_times (const char *name)
{
  /* Changing files again.  This means currently collected time
     is charged against header time, and body time starts back at 0.  */
  if (flag_detailed_statistics)
    {
      int this_time = get_run_time ();
      struct c_fileinfo *file = get_fileinfo (name);
      header_time += this_time - body_time;
      file->time += this_time - body_time;
      body_time = this_time;
    }
}

static int
dump_one_header (splay_tree_node n, void * ARG_UNUSED (dummy))
{
  print_time ((const char *) n->key,
	      ((struct c_fileinfo *) n->value)->time);
  return 0;
}

void
dump_time_statistics (void)
{
  struct c_fileinfo *file = get_fileinfo (input_filename);
  int this_time = get_run_time ();
  file->time += this_time - body_time;

  fprintf (stderr, "\n******\n");
  print_time ("header files (total)", header_time);
  print_time ("main file (total)", this_time - body_time);
  fprintf (stderr, "ratio = %g : 1\n",
	   (double) header_time / (double) (this_time - body_time));
  fprintf (stderr, "\n******\n");

  splay_tree_foreach (file_info_tree, dump_one_header, 0);
}

static void
cb_ident (cpp_reader * ARG_UNUSED (pfile),
	  unsigned int ARG_UNUSED (line),
	  const cpp_string * ARG_UNUSED (str))
{
#ifdef ASM_OUTPUT_IDENT
  if (!flag_no_ident)
    {
      /* Convert escapes in the string.  */
      cpp_string cstr = { 0, 0 };
      if (cpp_interpret_string (pfile, str, 1, &cstr, false))
	{
	  ASM_OUTPUT_IDENT (asm_out_file, (const char *) cstr.text);
	  free ((void *) cstr.text);
	}
    }
#endif
}

/* Called at the start of every non-empty line.  TOKEN is the first
   lexed token on the line.  Used for diagnostic line numbers.  */
static void
cb_line_change (cpp_reader * ARG_UNUSED (pfile), const cpp_token *token,
		int parsing_args)
{
  if (token->type != CPP_EOF && !parsing_args)
#ifdef USE_MAPPED_LOCATION
    input_location = token->src_loc;
#else
    {
      source_location loc = token->src_loc;
      const struct line_map *map = linemap_lookup (&line_table, loc);
      input_line = SOURCE_LINE (map, loc);
    }
#endif
}

void
fe_file_change (const struct line_map *new_map)
{
  if (new_map == NULL)
    return;

  if (new_map->reason == LC_ENTER)
    {
      /* Don't stack the main buffer on the input stack;
	 we already did in compile_file.  */
      if (!MAIN_FILE_P (new_map))
	{
#ifdef USE_MAPPED_LOCATION
          int included_at = LAST_SOURCE_LINE_LOCATION (new_map - 1);

	  input_location = included_at;
	  push_srcloc (new_map->start_location);
#else
          int included_at = LAST_SOURCE_LINE (new_map - 1);

	  input_line = included_at;
	  push_srcloc (new_map->to_file, 1);
#endif
	  (*debug_hooks->start_source_file) (included_at, new_map->to_file);
#ifndef NO_IMPLICIT_EXTERN_C
	  if (c_header_level)
	    ++c_header_level;
	  else if (new_map->sysp == 2)
	    {
	      c_header_level = 1;
	      ++pending_lang_change;
	    }
#endif
	}
    }
  else if (new_map->reason == LC_LEAVE)
    {
#ifndef NO_IMPLICIT_EXTERN_C
      if (c_header_level && --c_header_level == 0)
	{
	  if (new_map->sysp == 2)
	    warning (0, "badly nested C headers from preprocessor");
	  --pending_lang_change;
	}
#endif
      pop_srcloc ();

      (*debug_hooks->end_source_file) (new_map->to_line);
    }

  update_header_times (new_map->to_file);
  in_system_header = new_map->sysp != 0;
#ifdef USE_MAPPED_LOCATION
  input_location = new_map->start_location;
#else
  input_filename = new_map->to_file;
  input_line = new_map->to_line;
#endif
}

static void
cb_def_pragma (cpp_reader *pfile, source_location loc)
{
  /* Issue a warning message if we have been asked to do so.  Ignore
     unknown pragmas in system headers unless an explicit
     -Wunknown-pragmas has been given.  */
  if (warn_unknown_pragmas > in_system_header)
    {
      const unsigned char *space, *name;
      const cpp_token *s;
#ifndef USE_MAPPED_LOCATION
      location_t fe_loc;
      const struct line_map *map = linemap_lookup (&line_table, loc);
      fe_loc.file = map->to_file;
      fe_loc.line = SOURCE_LINE (map, loc);
#else
      location_t fe_loc = loc;
#endif

      space = name = (const unsigned char *) "";
      s = cpp_get_token (pfile);
      if (s->type != CPP_EOF)
	{
	  space = cpp_token_as_text (pfile, s);
	  s = cpp_get_token (pfile);
	  if (s->type == CPP_NAME)
	    name = cpp_token_as_text (pfile, s);
	}

      warning (OPT_Wunknown_pragmas, "%Hignoring #pragma %s %s",
	       &fe_loc, space, name);
    }
}

/* #define callback for DWARF and DWARF2 debug info.  */
static void
cb_define (cpp_reader *pfile, source_location loc, cpp_hashnode *node)
{
  const struct line_map *map = linemap_lookup (&line_table, loc);
  (*debug_hooks->define) (SOURCE_LINE (map, loc),
			  (const char *) cpp_macro_definition (pfile, node));
}

/* #undef callback for DWARF and DWARF2 debug info.  */
static void
cb_undef (cpp_reader * ARG_UNUSED (pfile), source_location loc,
	  cpp_hashnode *node)
{
  const struct line_map *map = linemap_lookup (&line_table, loc);
  (*debug_hooks->undef) (SOURCE_LINE (map, loc),
			 (const char *) NODE_NAME (node));
}

/* Read a token and return its type.  Fill *VALUE with its value, if
   applicable.  Fill *CPP_FLAGS with the token's flags, if it is
   non-NULL.  */

enum cpp_ttype
c_lex_with_flags (tree *value, location_t *loc, unsigned char *cpp_flags)
{
  static bool no_more_pch;
  const cpp_token *tok;
  enum cpp_ttype type;

  timevar_push (TV_CPP);
 retry:
  tok = cpp_get_token (parse_in);
  type = tok->type;
  
 retry_after_at:
#ifdef USE_MAPPED_LOCATION
  *loc = tok->src_loc;
#else
  *loc = input_location;
#endif
  switch (type)
    {
    case CPP_PADDING:
      goto retry;
      
    case CPP_NAME:
      *value = HT_IDENT_TO_GCC_IDENT (HT_NODE (tok->val.node));
      break;

    case CPP_NUMBER:
      {
	unsigned int flags = cpp_classify_number (parse_in, tok);

	switch (flags & CPP_N_CATEGORY)
	  {
	  case CPP_N_INVALID:
	    /* cpplib has issued an error.  */
	    *value = error_mark_node;
	    break;

	  case CPP_N_INTEGER:
	    *value = interpret_integer (tok, flags);
	    break;

	  case CPP_N_FLOATING:
	    *value = interpret_float (tok, flags);
	    break;

	  default:
	    gcc_unreachable ();
	  }
      }
      break;

    case CPP_ATSIGN:
      /* An @ may give the next token special significance in Objective-C.  */
      if (c_dialect_objc ())
	{
	  location_t atloc = input_location;
	  
	retry_at:
	  tok = cpp_get_token (parse_in);
	  type = tok->type;
	  switch (type)
	    {
	    case CPP_PADDING:
	      goto retry_at;
	      
	    case CPP_STRING:
	    case CPP_WSTRING:
	      type = lex_string (tok, value, true);
	      break;

	    case CPP_NAME:
	      *value = HT_IDENT_TO_GCC_IDENT (HT_NODE (tok->val.node));
	      if (objc_is_reserved_word (*value))
		{
		  type = CPP_AT_NAME;
		  break;
		}
	      /* FALLTHROUGH */

	    default:
	      /* ... or not.  */
	      error ("%Hstray %<@%> in program", &atloc);
	      goto retry_after_at;
	    }
	  break;
	}

      /* FALLTHROUGH */
    case CPP_HASH:
    case CPP_PASTE:
      {
	unsigned char name[4];
	
	*cpp_spell_token (parse_in, tok, name, true) = 0;
	
	error ("stray %qs in program", name);
      }
      
      goto retry;

    case CPP_OTHER:
      {
	cppchar_t c = tok->val.str.text[0];

	if (c == '"' || c == '\'')
	  error ("missing terminating %c character", (int) c);
	else if (ISGRAPH (c))
	  error ("stray %qc in program", (int) c);
	else
	  error ("stray %<\\%o%> in program", (int) c);
      }
      goto retry;

    case CPP_CHAR:
    case CPP_WCHAR:
      *value = lex_charconst (tok);
      break;

    case CPP_STRING:
    case CPP_WSTRING:
      if (!c_lex_return_raw_strings)
	{
	  type = lex_string (tok, value, false);
	  break;
	}
      
      /* FALLTHROUGH */

    case CPP_PRAGMA:
      *value = build_string (tok->val.str.len, (char *) tok->val.str.text);
      break;

      /* These tokens should not be visible outside cpplib.  */
    case CPP_HEADER_NAME:
    case CPP_COMMENT:
    case CPP_MACRO_ARG:
      gcc_unreachable ();

    default:
      *value = NULL_TREE;
      break;
    }

  if (cpp_flags)
    *cpp_flags = tok->flags;

  if (!no_more_pch)
    {
      no_more_pch = true;
      c_common_no_more_pch ();
    }
  
  timevar_pop (TV_CPP);
  
  return type;
}

enum cpp_ttype
c_lex (tree *value)
{
  location_t loc;
  return c_lex_with_flags (value, &loc, NULL);
}

/* Returns the narrowest C-visible unsigned type, starting with the
   minimum specified by FLAGS, that can fit HIGH:LOW, or itk_none if
   there isn't one.  */

static enum integer_type_kind
narrowest_unsigned_type (unsigned HOST_WIDE_INT low,
			 unsigned HOST_WIDE_INT high,
			 unsigned int flags)
{
  enum integer_type_kind itk;

  if ((flags & CPP_N_WIDTH) == CPP_N_SMALL)
    itk = itk_unsigned_int;
  else if ((flags & CPP_N_WIDTH) == CPP_N_MEDIUM)
    itk = itk_unsigned_long;
  else
    itk = itk_unsigned_long_long;

  for (; itk < itk_none; itk += 2 /* skip unsigned types */)
    {
      tree upper = TYPE_MAX_VALUE (integer_types[itk]);

      if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (upper) > high
	  || ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (upper) == high
	      && TREE_INT_CST_LOW (upper) >= low))
	return itk;
    }

  return itk_none;
}

/* Ditto, but narrowest signed type.  */
static enum integer_type_kind
narrowest_signed_type (unsigned HOST_WIDE_INT low,
		       unsigned HOST_WIDE_INT high, unsigned int flags)
{
  enum integer_type_kind itk;

  if ((flags & CPP_N_WIDTH) == CPP_N_SMALL)
    itk = itk_int;
  else if ((flags & CPP_N_WIDTH) == CPP_N_MEDIUM)
    itk = itk_long;
  else
    itk = itk_long_long;


  for (; itk < itk_none; itk += 2 /* skip signed types */)
    {
      tree upper = TYPE_MAX_VALUE (integer_types[itk]);
      
      if ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (upper) > high
	  || ((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (upper) == high
	      && TREE_INT_CST_LOW (upper) >= low))
	return itk;
    }

  return itk_none;
}

/* Interpret TOKEN, an integer with FLAGS as classified by cpplib.  */
static tree
interpret_integer (const cpp_token *token, unsigned int flags)
{
  tree value, type;
  enum integer_type_kind itk;
  cpp_num integer;
  cpp_options *options = cpp_get_options (parse_in);

  integer = cpp_interpret_integer (parse_in, token, flags);
  integer = cpp_num_sign_extend (integer, options->precision);

  /* The type of a constant with a U suffix is straightforward.  */
  if (flags & CPP_N_UNSIGNED)
    itk = narrowest_unsigned_type (integer.low, integer.high, flags);
  else
    {
      /* The type of a potentially-signed integer constant varies
	 depending on the base it's in, the standard in use, and the
	 length suffixes.  */
      enum integer_type_kind itk_u
	= narrowest_unsigned_type (integer.low, integer.high, flags);
      enum integer_type_kind itk_s
	= narrowest_signed_type (integer.low, integer.high, flags);

      /* In both C89 and C99, octal and hex constants may be signed or
	 unsigned, whichever fits tighter.  We do not warn about this
	 choice differing from the traditional choice, as the constant
	 is probably a bit pattern and either way will work.  */
      if ((flags & CPP_N_RADIX) != CPP_N_DECIMAL)
	itk = MIN (itk_u, itk_s);
      else
	{
	  /* In C99, decimal constants are always signed.
	     In C89, decimal constants that don't fit in long have
	     undefined behavior; we try to make them unsigned long.
	     In GCC's extended C89, that last is true of decimal
	     constants that don't fit in long long, too.  */

	  itk = itk_s;
	  if (itk_s > itk_u && itk_s > itk_long)
	    {
	      if (!flag_isoc99)
		{
		  if (itk_u < itk_unsigned_long)
		    itk_u = itk_unsigned_long;
		  itk = itk_u;
		  warning (0, "this decimal constant is unsigned only in ISO C90");
		}
	      else
		warning (OPT_Wtraditional,
			 "this decimal constant would be unsigned in ISO C90");
	    }
	}
    }

  if (itk == itk_none)
    /* cpplib has already issued a warning for overflow.  */
    type = ((flags & CPP_N_UNSIGNED)
	    ? widest_unsigned_literal_type_node
	    : widest_integer_literal_type_node);
  else
    type = integer_types[itk];

  if (itk > itk_unsigned_long
      && (flags & CPP_N_WIDTH) != CPP_N_LARGE
      && !in_system_header && !flag_isoc99)
    pedwarn ("integer constant is too large for %qs type",
	     (flags & CPP_N_UNSIGNED) ? "unsigned long" : "long");

  value = build_int_cst_wide (type, integer.low, integer.high);

  /* Convert imaginary to a complex type.  */
  if (flags & CPP_N_IMAGINARY)
    value = build_complex (NULL_TREE, build_int_cst (type, 0), value);

  return value;
}

/* Interpret TOKEN, a floating point number with FLAGS as classified
   by cpplib.  */
static tree
interpret_float (const cpp_token *token, unsigned int flags)
{
  tree type;
  tree value;
  REAL_VALUE_TYPE real;
  char *copy;
  size_t copylen;
  const char *type_name;

  /* FIXME: make %T work in error/warning, then we don't need type_name.  */
  if ((flags & CPP_N_WIDTH) == CPP_N_LARGE)
    {
      type = long_double_type_node;
      type_name = "long double";
    }
  else if ((flags & CPP_N_WIDTH) == CPP_N_SMALL
	   || flag_single_precision_constant)
    {
      type = float_type_node;
      type_name = "float";
    }
  else
    {
      type = double_type_node;
      type_name = "double";
    }

  /* Copy the constant to a nul-terminated buffer.  If the constant
     has any suffixes, cut them off; REAL_VALUE_ATOF/ REAL_VALUE_HTOF
     can't handle them.  */
  copylen = token->val.str.len;
  if ((flags & CPP_N_WIDTH) != CPP_N_MEDIUM)
    /* Must be an F or L suffix.  */
    copylen--;
  if (flags & CPP_N_IMAGINARY)
    /* I or J suffix.  */
    copylen--;

  copy = (char *) alloca (copylen + 1);
  memcpy (copy, token->val.str.text, copylen);
  copy[copylen] = '\0';

  real_from_string (&real, copy);
  real_convert (&real, TYPE_MODE (type), &real);

  /* Both C and C++ require a diagnostic for a floating constant
     outside the range of representable values of its type.  Since we
     have __builtin_inf* to produce an infinity, it might now be
     appropriate for this to be a mandatory pedwarn rather than
     conditioned on -pedantic.  */
  if (REAL_VALUE_ISINF (real) && pedantic)
    pedwarn ("floating constant exceeds range of %<%s%>", type_name);

  /* Create a node with determined type and value.  */
  value = build_real (type, real);
  if (flags & CPP_N_IMAGINARY)
    value = build_complex (NULL_TREE, convert (type, integer_zero_node), value);

  return value;
}

/* Convert a series of STRING and/or WSTRING tokens into a tree,
   performing string constant concatenation.  TOK is the first of
   these.  VALP is the location to write the string into.  OBJC_STRING
   indicates whether an '@' token preceded the incoming token.
   Returns the CPP token type of the result (CPP_STRING, CPP_WSTRING,
   or CPP_OBJC_STRING).

   This is unfortunately more work than it should be.  If any of the
   strings in the series has an L prefix, the result is a wide string
   (6.4.5p4).  Whether or not the result is a wide string affects the
   meaning of octal and hexadecimal escapes (6.4.4.4p6,9).  But escape
   sequences do not continue across the boundary between two strings in
   a series (6.4.5p7), so we must not lose the boundaries.  Therefore
   cpp_interpret_string takes a vector of cpp_string structures, which
   we must arrange to provide.  */

static enum cpp_ttype
lex_string (const cpp_token *tok, tree *valp, bool objc_string)
{
  tree value;
  bool wide = false;
  size_t concats = 0;
  struct obstack str_ob;
  cpp_string istr;

  /* Try to avoid the overhead of creating and destroying an obstack
     for the common case of just one string.  */
  cpp_string str = tok->val.str;
  cpp_string *strs = &str;

  if (tok->type == CPP_WSTRING)
    wide = true;

 retry:
  tok = cpp_get_token (parse_in);
  switch (tok->type)
    {
    case CPP_PADDING:
      goto retry;
    case CPP_ATSIGN:
      if (c_dialect_objc ())
	{
	  objc_string = true;
	  goto retry;
	}
      /* FALLTHROUGH */
      
    default:
      break;
      
    case CPP_WSTRING:
      wide = true;
      /* FALLTHROUGH */
      
    case CPP_STRING:
      if (!concats)
	{
	  gcc_obstack_init (&str_ob);
	  obstack_grow (&str_ob, &str, sizeof (cpp_string));
	}
	
      concats++;
      obstack_grow (&str_ob, &tok->val.str, sizeof (cpp_string));
      goto retry;
    }

  /* We have read one more token than we want.  */
  _cpp_backup_tokens (parse_in, 1);
  if (concats)
    strs = XOBFINISH (&str_ob, cpp_string *);

  if (concats && !objc_string && !in_system_header)
    warning (OPT_Wtraditional,
	     "traditional C rejects string constant concatenation");

  if ((c_lex_string_translate
       ? cpp_interpret_string : cpp_interpret_string_notranslate)
      (parse_in, strs, concats + 1, &istr, wide))
    {
      value = build_string (istr.len, (char *) istr.text);
      free ((void *) istr.text);

      if (c_lex_string_translate == -1)
	{
	  int xlated = cpp_interpret_string_notranslate (parse_in, strs,
							 concats + 1,
							 &istr, wide);
	  /* Assume that, if we managed to translate the string above,
	     then the untranslated parsing will always succeed.  */
	  gcc_assert (xlated);
	  
	  if (TREE_STRING_LENGTH (value) != (int) istr.len
	      || 0 != strncmp (TREE_STRING_POINTER (value), (char *) istr.text,
			       istr.len))
	    {
	      /* Arrange for us to return the untranslated string in
		 *valp, but to set up the C type of the translated
		 one.  */
	      *valp = build_string (istr.len, (char *) istr.text);
	      valp = &TREE_CHAIN (*valp);
	    }
	  free ((void *) istr.text);
	}
    }
  else
    {
      /* Callers cannot generally handle error_mark_node in this context,
	 so return the empty string instead.  cpp_interpret_string has
	 issued an error.  */
      if (wide)
	value = build_string (TYPE_PRECISION (wchar_type_node)
			      / TYPE_PRECISION (char_type_node),
			      "\0\0\0");  /* widest supported wchar_t
					     is 32 bits */
      else
	value = build_string (1, "");
    }

  TREE_TYPE (value) = wide ? wchar_array_type_node : char_array_type_node;
  *valp = fix_string_type (value);

  if (concats)
    obstack_free (&str_ob, 0);

  return objc_string ? CPP_OBJC_STRING : wide ? CPP_WSTRING : CPP_STRING;
}

/* Converts a (possibly wide) character constant token into a tree.  */
static tree
lex_charconst (const cpp_token *token)
{
  cppchar_t result;
  tree type, value;
  unsigned int chars_seen;
  int unsignedp;

  result = cpp_interpret_charconst (parse_in, token,
				    &chars_seen, &unsignedp);

  if (token->type == CPP_WCHAR)
    type = wchar_type_node;
  /* In C, a character constant has type 'int'.
     In C++ 'char', but multi-char charconsts have type 'int'.  */
  else if (!c_dialect_cxx () || chars_seen > 1)
    type = integer_type_node;
  else
    type = char_type_node;

  /* Cast to cppchar_signed_t to get correct sign-extension of RESULT
     before possibly widening to HOST_WIDE_INT for build_int_cst.  */
  if (unsignedp || (cppchar_signed_t) result >= 0)
    value = build_int_cst_wide (type, result, 0);
  else
    value = build_int_cst_wide (type, (cppchar_signed_t) result, -1);

  return value;
}