xref: /netbsd-src/external/gpl3/gcc.old/dist/libcpp/init.c (revision 53b02e147d4ed531c0d2a5ca9b3e8026ba3e99b5)
1 /* CPP Library.
2    Copyright (C) 1986-2019 Free Software Foundation, Inc.
3    Contributed by Per Bothner, 1994-95.
4    Based on CCCP program by Paul Rubin, June 1986
5    Adapted to ANSI C, Richard Stallman, Jan 1987
6 
7 This program is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by the
9 Free Software Foundation; either version 3, or (at your option) any
10 later version.
11 
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 GNU General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with this program; see the file COPYING3.  If not see
19 <http://www.gnu.org/licenses/>.  */
20 
21 #include "config.h"
22 #include "system.h"
23 #include "cpplib.h"
24 #include "internal.h"
25 #include "mkdeps.h"
26 #include "localedir.h"
27 #include "filenames.h"
28 
29 #ifndef ENABLE_CANONICAL_SYSTEM_HEADERS
30 #ifdef HAVE_DOS_BASED_FILE_SYSTEM
31 #define ENABLE_CANONICAL_SYSTEM_HEADERS 1
32 #else
33 #define ENABLE_CANONICAL_SYSTEM_HEADERS 0
34 #endif
35 #endif
36 
37 static void init_library (void);
38 static void mark_named_operators (cpp_reader *, int);
39 static void read_original_filename (cpp_reader *);
40 static void read_original_directory (cpp_reader *);
41 static void post_options (cpp_reader *);
42 
43 /* If we have designated initializers (GCC >2.7) these tables can be
44    initialized, constant data.  Otherwise, they have to be filled in at
45    runtime.  */
46 #if HAVE_DESIGNATED_INITIALIZERS
47 
48 #define init_trigraph_map()  /* Nothing.  */
49 #define TRIGRAPH_MAP \
50 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
51 
52 #define END };
53 #define s(p, v) [p] = v,
54 
55 #else
56 
57 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
58  static void init_trigraph_map (void) { \
59  unsigned char *x = _cpp_trigraph_map;
60 
61 #define END }
62 #define s(p, v) x[p] = v;
63 
64 #endif
65 
66 TRIGRAPH_MAP
67   s('=', '#')	s(')', ']')	s('!', '|')
68   s('(', '[')	s('\'', '^')	s('>', '}')
69   s('/', '\\')	s('<', '{')	s('-', '~')
70 END
71 
72 #undef s
73 #undef END
74 #undef TRIGRAPH_MAP
75 
76 /* A set of booleans indicating what CPP features each source language
77    requires.  */
78 struct lang_flags
79 {
80   char c99;
81   char cplusplus;
82   char extended_numbers;
83   char extended_identifiers;
84   char c11_identifiers;
85   char std;
86   char digraphs;
87   char uliterals;
88   char rliterals;
89   char user_literals;
90   char binary_constants;
91   char digit_separators;
92   char trigraphs;
93   char utf8_char_literals;
94   char va_opt;
95 };
96 
97 static const struct lang_flags lang_defaults[] =
98 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt */
99   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1 },
100   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1 },
101   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1 },
102   /* GNUC17   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1 },
103   /* GNUC2X   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1 },
104   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0,      0 },
105   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0 },
106   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0 },
107   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0 },
108   /* STDC17   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0 },
109   /* STDC2X   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0 },
110   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1 },
111   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0 },
112   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0,      1 },
113   /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0,      0 },
114   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0,      1 },
115   /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0,      0 },
116   /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1 },
117   /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      0 },
118   /* GNUCXX2A */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1 },
119   /* CXX2A    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1 },
120   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0,      0 }
121 };
122 
123 /* Sets internal flags correctly for a given language.  */
124 void
125 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
126 {
127   const struct lang_flags *l = &lang_defaults[(int) lang];
128 
129   CPP_OPTION (pfile, lang) = lang;
130 
131   CPP_OPTION (pfile, c99)			 = l->c99;
132   CPP_OPTION (pfile, cplusplus)			 = l->cplusplus;
133   CPP_OPTION (pfile, extended_numbers)		 = l->extended_numbers;
134   CPP_OPTION (pfile, extended_identifiers)	 = l->extended_identifiers;
135   CPP_OPTION (pfile, c11_identifiers)		 = l->c11_identifiers;
136   CPP_OPTION (pfile, std)			 = l->std;
137   CPP_OPTION (pfile, digraphs)			 = l->digraphs;
138   CPP_OPTION (pfile, uliterals)			 = l->uliterals;
139   CPP_OPTION (pfile, rliterals)			 = l->rliterals;
140   CPP_OPTION (pfile, user_literals)		 = l->user_literals;
141   CPP_OPTION (pfile, binary_constants)		 = l->binary_constants;
142   CPP_OPTION (pfile, digit_separators)		 = l->digit_separators;
143   CPP_OPTION (pfile, trigraphs)			 = l->trigraphs;
144   CPP_OPTION (pfile, utf8_char_literals)	 = l->utf8_char_literals;
145   CPP_OPTION (pfile, va_opt)			 = l->va_opt;
146 }
147 
148 /* Initialize library global state.  */
149 static void
150 init_library (void)
151 {
152   static int initialized = 0;
153 
154   if (! initialized)
155     {
156       initialized = 1;
157 
158       _cpp_init_lexer ();
159 
160       /* Set up the trigraph map.  This doesn't need to do anything if
161 	 we were compiled with a compiler that supports C99 designated
162 	 initializers.  */
163       init_trigraph_map ();
164 
165 #ifdef ENABLE_NLS
166        (void) bindtextdomain (PACKAGE, LOCALEDIR);
167 #endif
168     }
169 }
170 
171 /* Initialize a cpp_reader structure.  */
172 cpp_reader *
173 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
174 		   struct line_maps *line_table)
175 {
176   cpp_reader *pfile;
177 
178   /* Initialize this instance of the library if it hasn't been already.  */
179   init_library ();
180 
181   pfile = XCNEW (cpp_reader);
182   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
183 
184   cpp_set_lang (pfile, lang);
185   CPP_OPTION (pfile, warn_multichar) = 1;
186   CPP_OPTION (pfile, discard_comments) = 1;
187   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
188   CPP_OPTION (pfile, tabstop) = 8;
189   CPP_OPTION (pfile, operator_names) = 1;
190   CPP_OPTION (pfile, warn_trigraphs) = 2;
191   CPP_OPTION (pfile, warn_endif_labels) = 1;
192   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
193   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
194   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
195   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
196   CPP_OPTION (pfile, dollars_in_ident) = 1;
197   CPP_OPTION (pfile, warn_dollars) = 1;
198   CPP_OPTION (pfile, warn_variadic_macros) = 1;
199   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
200   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
201   /* By default, track locations of tokens resulting from macro
202      expansion.  The '2' means, track the locations with the highest
203      accuracy.  Read the comments for struct
204      cpp_options::track_macro_expansion to learn about the other
205      values.  */
206   CPP_OPTION (pfile, track_macro_expansion) = 2;
207   CPP_OPTION (pfile, warn_normalize) = normalized_C;
208   CPP_OPTION (pfile, warn_literal_suffix) = 1;
209   CPP_OPTION (pfile, canonical_system_headers)
210       = ENABLE_CANONICAL_SYSTEM_HEADERS;
211   CPP_OPTION (pfile, ext_numeric_literals) = 1;
212   CPP_OPTION (pfile, warn_date_time) = 0;
213 
214   /* Default CPP arithmetic to something sensible for the host for the
215      benefit of dumb users like fix-header.  */
216   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
217   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
218   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
219   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
220   CPP_OPTION (pfile, unsigned_char) = 0;
221   CPP_OPTION (pfile, unsigned_wchar) = 1;
222   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
223 
224   /* Default to no charset conversion.  */
225   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
226   CPP_OPTION (pfile, wide_charset) = 0;
227 
228   /* Default the input character set to UTF-8.  */
229   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
230 
231   /* A fake empty "directory" used as the starting point for files
232      looked up without a search path.  Name cannot be '/' because we
233      don't want to prepend anything at all to filenames using it.  All
234      other entries are correct zero-initialized.  */
235   pfile->no_search_path.name = (char *) "";
236 
237   /* Initialize the line map.  */
238   pfile->line_table = line_table;
239 
240   /* Initialize lexer state.  */
241   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
242 
243   /* Set up static tokens.  */
244   pfile->avoid_paste.type = CPP_PADDING;
245   pfile->avoid_paste.val.source = NULL;
246   pfile->eof.type = CPP_EOF;
247   pfile->eof.flags = 0;
248 
249   /* Create a token buffer for the lexer.  */
250   _cpp_init_tokenrun (&pfile->base_run, 250);
251   pfile->cur_run = &pfile->base_run;
252   pfile->cur_token = pfile->base_run.base;
253 
254   /* Initialize the base context.  */
255   pfile->context = &pfile->base_context;
256   pfile->base_context.c.macro = 0;
257   pfile->base_context.prev = pfile->base_context.next = 0;
258 
259   /* Aligned and unaligned storage.  */
260   pfile->a_buff = _cpp_get_buff (pfile, 0);
261   pfile->u_buff = _cpp_get_buff (pfile, 0);
262 
263   /* Initialize table for push_macro/pop_macro.  */
264   pfile->pushed_macros = 0;
265 
266   /* Do not force token locations by default.  */
267   pfile->forced_token_location = 0;
268 
269   /* Initialize source_date_epoch to -2 (not yet set).  */
270   pfile->source_date_epoch = (time_t) -2;
271 
272   /* The expression parser stack.  */
273   _cpp_expand_op_stack (pfile);
274 
275   /* Initialize the buffer obstack.  */
276   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
277 
278   _cpp_init_files (pfile);
279 
280   _cpp_init_hashtable (pfile, table);
281 
282   return pfile;
283 }
284 
285 /* Set the line_table entry in PFILE.  This is called after reading a
286    PCH file, as the old line_table will be incorrect.  */
287 void
288 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
289 {
290   pfile->line_table = line_table;
291 }
292 
293 /* Free resources used by PFILE.  Accessing PFILE after this function
294    returns leads to undefined behavior.  Returns the error count.  */
295 void
296 cpp_destroy (cpp_reader *pfile)
297 {
298   cpp_context *context, *contextn;
299   struct def_pragma_macro *pmacro;
300   tokenrun *run, *runn;
301   int i;
302 
303   free (pfile->op_stack);
304 
305   while (CPP_BUFFER (pfile) != NULL)
306     _cpp_pop_buffer (pfile);
307 
308   free (pfile->out.base);
309 
310   if (pfile->macro_buffer)
311     {
312       free (pfile->macro_buffer);
313       pfile->macro_buffer = NULL;
314       pfile->macro_buffer_len = 0;
315     }
316 
317   if (pfile->deps)
318     deps_free (pfile->deps);
319   obstack_free (&pfile->buffer_ob, 0);
320 
321   _cpp_destroy_hashtable (pfile);
322   _cpp_cleanup_files (pfile);
323   _cpp_destroy_iconv (pfile);
324 
325   _cpp_free_buff (pfile->a_buff);
326   _cpp_free_buff (pfile->u_buff);
327   _cpp_free_buff (pfile->free_buffs);
328 
329   for (run = &pfile->base_run; run; run = runn)
330     {
331       runn = run->next;
332       free (run->base);
333       if (run != &pfile->base_run)
334 	free (run);
335     }
336 
337   for (context = pfile->base_context.next; context; context = contextn)
338     {
339       contextn = context->next;
340       free (context);
341     }
342 
343   if (pfile->comments.entries)
344     {
345       for (i = 0; i < pfile->comments.count; i++)
346 	free (pfile->comments.entries[i].comment);
347 
348       free (pfile->comments.entries);
349     }
350   if (pfile->pushed_macros)
351     {
352       do
353 	{
354 	  pmacro = pfile->pushed_macros;
355 	  pfile->pushed_macros = pmacro->next;
356 	  free (pmacro->name);
357 	  free (pmacro);
358 	}
359       while (pfile->pushed_macros);
360     }
361 
362   free (pfile);
363 }
364 
365 /* This structure defines one built-in identifier.  A node will be
366    entered in the hash table under the name NAME, with value VALUE.
367 
368    There are two tables of these.  builtin_array holds all the
369    "builtin" macros: these are handled by builtin_macro() in
370    macro.c.  Builtin is somewhat of a misnomer -- the property of
371    interest is that these macros require special code to compute their
372    expansions.  The value is a "cpp_builtin_type" enumerator.
373 
374    operator_array holds the C++ named operators.  These are keywords
375    which act as aliases for punctuators.  In C++, they cannot be
376    altered through #define, and #if recognizes them as operators.  In
377    C, these are not entered into the hash table at all (but see
378    <iso646.h>).  The value is a token-type enumerator.  */
379 struct builtin_macro
380 {
381   const uchar *const name;
382   const unsigned short len;
383   const unsigned short value;
384   const bool always_warn_if_redefined;
385 };
386 
387 #define B(n, t, f)    { DSC(n), t, f }
388 static const struct builtin_macro builtin_array[] =
389 {
390   B("__TIMESTAMP__",	 BT_TIMESTAMP,     false),
391   B("__TIME__",		 BT_TIME,          false),
392   B("__DATE__",		 BT_DATE,          false),
393   B("__FILE__",		 BT_FILE,          false),
394   B("__BASE_FILE__",	 BT_BASE_FILE,     false),
395   B("__LINE__",		 BT_SPECLINE,      true),
396   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
397   B("__COUNTER__",	 BT_COUNTER,       true),
398   B("__has_attribute",	 BT_HAS_ATTRIBUTE, true),
399   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
400   /* Keep builtins not used for -traditional-cpp at the end, and
401      update init_builtins() if any more are added.  */
402   B("_Pragma",		 BT_PRAGMA,        true),
403   B("__STDC__",		 BT_STDC,          true),
404 };
405 #undef B
406 
407 struct builtin_operator
408 {
409   const uchar *const name;
410   const unsigned short len;
411   const unsigned short value;
412 };
413 
414 #define B(n, t)    { DSC(n), t }
415 static const struct builtin_operator operator_array[] =
416 {
417   B("and",	CPP_AND_AND),
418   B("and_eq",	CPP_AND_EQ),
419   B("bitand",	CPP_AND),
420   B("bitor",	CPP_OR),
421   B("compl",	CPP_COMPL),
422   B("not",	CPP_NOT),
423   B("not_eq",	CPP_NOT_EQ),
424   B("or",	CPP_OR_OR),
425   B("or_eq",	CPP_OR_EQ),
426   B("xor",	CPP_XOR),
427   B("xor_eq",	CPP_XOR_EQ)
428 };
429 #undef B
430 
431 /* Mark the C++ named operators in the hash table.  */
432 static void
433 mark_named_operators (cpp_reader *pfile, int flags)
434 {
435   const struct builtin_operator *b;
436 
437   for (b = operator_array;
438        b < (operator_array + ARRAY_SIZE (operator_array));
439        b++)
440     {
441       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
442       hp->flags |= flags;
443       hp->is_directive = 0;
444       hp->directive_index = b->value;
445     }
446 }
447 
448 /* Helper function of cpp_type2name. Return the string associated with
449    named operator TYPE.  */
450 const char *
451 cpp_named_operator2name (enum cpp_ttype type)
452 {
453   const struct builtin_operator *b;
454 
455   for (b = operator_array;
456        b < (operator_array + ARRAY_SIZE (operator_array));
457        b++)
458     {
459       if (type == b->value)
460 	return (const char *) b->name;
461     }
462 
463   return NULL;
464 }
465 
466 void
467 cpp_init_special_builtins (cpp_reader *pfile)
468 {
469   const struct builtin_macro *b;
470   size_t n = ARRAY_SIZE (builtin_array);
471 
472   if (CPP_OPTION (pfile, traditional))
473     n -= 2;
474   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
475 	   || CPP_OPTION (pfile, std))
476     n--;
477 
478   for (b = builtin_array; b < builtin_array + n; b++)
479     {
480       if (b->value == BT_HAS_ATTRIBUTE
481 	  && (CPP_OPTION (pfile, lang) == CLK_ASM
482 	      || pfile->cb.has_attribute == NULL))
483 	continue;
484       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
485       hp->type = NT_BUILTIN_MACRO;
486       if (b->always_warn_if_redefined)
487 	hp->flags |= NODE_WARN;
488       hp->value.builtin = (enum cpp_builtin_type) b->value;
489     }
490 }
491 
492 /* Restore macro C to builtin macro definition.  */
493 
494 void
495 _cpp_restore_special_builtin (cpp_reader *pfile, struct def_pragma_macro *c)
496 {
497   size_t len = strlen (c->name);
498 
499   for (const struct builtin_macro *b = builtin_array;
500        b < builtin_array + ARRAY_SIZE (builtin_array); b++)
501     if (b->len == len && memcmp (c->name, b->name, len + 1) == 0)
502       {
503 	cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
504 	hp->type = NT_BUILTIN_MACRO;
505 	if (b->always_warn_if_redefined)
506 	  hp->flags |= NODE_WARN;
507 	hp->value.builtin = (enum cpp_builtin_type) b->value;
508       }
509 }
510 
511 /* Read the builtins table above and enter them, and language-specific
512    macros, into the hash table.  HOSTED is true if this is a hosted
513    environment.  */
514 void
515 cpp_init_builtins (cpp_reader *pfile, int hosted)
516 {
517   cpp_init_special_builtins (pfile);
518 
519   if (!CPP_OPTION (pfile, traditional)
520       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
521 	  || CPP_OPTION (pfile, std)))
522     _cpp_define_builtin (pfile, "__STDC__ 1");
523 
524   if (CPP_OPTION (pfile, cplusplus))
525     {
526       if (CPP_OPTION (pfile, lang) == CLK_CXX2A
527 	  || CPP_OPTION (pfile, lang) == CLK_GNUCXX2A)
528 	_cpp_define_builtin (pfile, "__cplusplus 201709L");
529       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
530 	  || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
531 	_cpp_define_builtin (pfile, "__cplusplus 201703L");
532       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
533 	  || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
534 	_cpp_define_builtin (pfile, "__cplusplus 201402L");
535       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
536 	       || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
537 	_cpp_define_builtin (pfile, "__cplusplus 201103L");
538       else
539 	_cpp_define_builtin (pfile, "__cplusplus 199711L");
540     }
541   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
542     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
543   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
544     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
545   else if (CPP_OPTION (pfile, lang) == CLK_STDC2X
546 	   || CPP_OPTION (pfile, lang) == CLK_GNUC2X)
547     _cpp_define_builtin (pfile, "__STDC_VERSION__ 202000L");
548   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
549 	   || CPP_OPTION (pfile, lang) == CLK_GNUC17)
550     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
551   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
552 	   || CPP_OPTION (pfile, lang) == CLK_GNUC11)
553     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
554   else if (CPP_OPTION (pfile, c99))
555     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
556 
557   if (CPP_OPTION (pfile, uliterals)
558       && !(CPP_OPTION (pfile, cplusplus)
559 	   && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
560 	    || CPP_OPTION (pfile, lang) == CLK_CXX98)))
561     {
562       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
563       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
564     }
565 
566   if (hosted)
567     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
568   else
569     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
570 
571   if (CPP_OPTION (pfile, objc))
572     _cpp_define_builtin (pfile, "__OBJC__ 1");
573 }
574 
575 /* Sanity-checks are dependent on command-line options, so it is
576    called as a subroutine of cpp_read_main_file.  */
577 #if CHECKING_P
578 static void sanity_checks (cpp_reader *);
579 static void sanity_checks (cpp_reader *pfile)
580 {
581   cppchar_t test = 0;
582   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
583 
584   /* Sanity checks for assumptions about CPP arithmetic and target
585      type precisions made by cpplib.  */
586   test--;
587   if (test < 1)
588     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
589 
590   if (CPP_OPTION (pfile, precision) > max_precision)
591     cpp_error (pfile, CPP_DL_ICE,
592 	       "preprocessor arithmetic has maximum precision of %lu bits;"
593 	       " target requires %lu bits",
594 	       (unsigned long) max_precision,
595 	       (unsigned long) CPP_OPTION (pfile, precision));
596 
597   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
598     cpp_error (pfile, CPP_DL_ICE,
599 	       "CPP arithmetic must be at least as precise as a target int");
600 
601   if (CPP_OPTION (pfile, char_precision) < 8)
602     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
603 
604   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
605     cpp_error (pfile, CPP_DL_ICE,
606 	       "target wchar_t is narrower than target char");
607 
608   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
609     cpp_error (pfile, CPP_DL_ICE,
610 	       "target int is narrower than target char");
611 
612   /* This is assumed in eval_token() and could be fixed if necessary.  */
613   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
614     cpp_error (pfile, CPP_DL_ICE,
615 	       "CPP half-integer narrower than CPP character");
616 
617   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
618     cpp_error (pfile, CPP_DL_ICE,
619 	       "CPP on this host cannot handle wide character constants over"
620 	       " %lu bits, but the target requires %lu bits",
621 	       (unsigned long) BITS_PER_CPPCHAR_T,
622 	       (unsigned long) CPP_OPTION (pfile, wchar_precision));
623 }
624 #else
625 # define sanity_checks(PFILE)
626 #endif
627 
628 /* This is called after options have been parsed, and partially
629    processed.  */
630 void
631 cpp_post_options (cpp_reader *pfile)
632 {
633   int flags;
634 
635   sanity_checks (pfile);
636 
637   post_options (pfile);
638 
639   /* Mark named operators before handling command line macros.  */
640   flags = 0;
641   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
642     flags |= NODE_OPERATOR;
643   if (CPP_OPTION (pfile, warn_cxx_operator_names))
644     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
645   if (flags != 0)
646     mark_named_operators (pfile, flags);
647 }
648 
649 /* Setup for processing input from the file named FNAME, or stdin if
650    it is the empty string.  Return the original filename
651    on success (e.g. foo.i->foo.c), or NULL on failure.  */
652 const char *
653 cpp_read_main_file (cpp_reader *pfile, const char *fname)
654 {
655   const location_t loc = 0;
656 
657   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
658     {
659       if (!pfile->deps)
660 	pfile->deps = deps_init ();
661 
662       /* Set the default target (if there is none already).  */
663       deps_add_default_target (pfile->deps, fname);
664     }
665 
666   pfile->main_file
667     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false,
668 		      loc);
669   if (_cpp_find_failed (pfile->main_file))
670     return NULL;
671 
672   _cpp_stack_file (pfile, pfile->main_file, false, loc);
673 
674   /* For foo.i, read the original filename foo.c now, for the benefit
675      of the front ends.  */
676   if (CPP_OPTION (pfile, preprocessed))
677     {
678       read_original_filename (pfile);
679       fname =
680 	ORDINARY_MAP_FILE_NAME
681 	((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
682     }
683   return fname;
684 }
685 
686 /* For preprocessed files, if the first tokens are of the form # NUM.
687    handle the directive so we know the original file name.  This will
688    generate file_change callbacks, which the front ends must handle
689    appropriately given their state of initialization.  */
690 static void
691 read_original_filename (cpp_reader *pfile)
692 {
693   const cpp_token *token, *token1;
694 
695   /* Lex ahead; if the first tokens are of the form # NUM, then
696      process the directive, otherwise back up.  */
697   token = _cpp_lex_direct (pfile);
698   if (token->type == CPP_HASH)
699     {
700       pfile->state.in_directive = 1;
701       token1 = _cpp_lex_direct (pfile);
702       _cpp_backup_tokens (pfile, 1);
703       pfile->state.in_directive = 0;
704 
705       /* If it's a #line directive, handle it.  */
706       if (token1->type == CPP_NUMBER
707 	  && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
708 	{
709 	  read_original_directory (pfile);
710 	  return;
711 	}
712     }
713 
714   /* Backup as if nothing happened.  */
715   _cpp_backup_tokens (pfile, 1);
716 }
717 
718 /* For preprocessed files, if the tokens following the first filename
719    line is of the form # <line> "/path/name//", handle the
720    directive so we know the original current directory.  */
721 static void
722 read_original_directory (cpp_reader *pfile)
723 {
724   const cpp_token *hash, *token;
725 
726   /* Lex ahead; if the first tokens are of the form # NUM, then
727      process the directive, otherwise back up.  */
728   hash = _cpp_lex_direct (pfile);
729   if (hash->type != CPP_HASH)
730     {
731       _cpp_backup_tokens (pfile, 1);
732       return;
733     }
734 
735   token = _cpp_lex_direct (pfile);
736 
737   if (token->type != CPP_NUMBER)
738     {
739       _cpp_backup_tokens (pfile, 2);
740       return;
741     }
742 
743   token = _cpp_lex_direct (pfile);
744 
745   if (token->type != CPP_STRING
746       || ! (token->val.str.len >= 5
747 	    && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
748 	    && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
749     {
750       _cpp_backup_tokens (pfile, 3);
751       return;
752     }
753 
754   if (pfile->cb.dir_change)
755     {
756       char *debugdir = (char *) alloca (token->val.str.len - 3);
757 
758       memcpy (debugdir, (const char *) token->val.str.text + 1,
759 	      token->val.str.len - 4);
760       debugdir[token->val.str.len - 4] = '\0';
761 
762       pfile->cb.dir_change (pfile, debugdir);
763     }
764 }
765 
766 /* This is called at the end of preprocessing.  It pops the last
767    buffer and writes dependency output.
768 
769    Maybe it should also reset state, such that you could call
770    cpp_start_read with a new filename to restart processing.  */
771 void
772 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
773 {
774   /* Warn about unused macros before popping the final buffer.  */
775   if (CPP_OPTION (pfile, warn_unused_macros))
776     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
777 
778   /* lex.c leaves the final buffer on the stack.  This it so that
779      it returns an unending stream of CPP_EOFs to the client.  If we
780      popped the buffer, we'd dereference a NULL buffer pointer and
781      segfault.  It's nice to allow the client to do worry-free excess
782      cpp_get_token calls.  */
783   while (pfile->buffer)
784     _cpp_pop_buffer (pfile);
785 
786   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
787       && deps_stream)
788     {
789       deps_write (pfile->deps, deps_stream, 72);
790 
791       if (CPP_OPTION (pfile, deps.phony_targets))
792 	deps_phony_targets (pfile->deps, deps_stream);
793     }
794 
795   /* Report on headers that could use multiple include guards.  */
796   if (CPP_OPTION (pfile, print_include_names))
797     _cpp_report_missing_guards (pfile);
798 }
799 
800 static void
801 post_options (cpp_reader *pfile)
802 {
803   /* -Wtraditional is not useful in C++ mode.  */
804   if (CPP_OPTION (pfile, cplusplus))
805     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
806 
807   /* Permanently disable macro expansion if we are rescanning
808      preprocessed text.  Read preprocesed source in ISO mode.  */
809   if (CPP_OPTION (pfile, preprocessed))
810     {
811       if (!CPP_OPTION (pfile, directives_only))
812 	pfile->state.prevent_expansion = 1;
813       CPP_OPTION (pfile, traditional) = 0;
814     }
815 
816   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
817     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
818 
819   if (CPP_OPTION (pfile, traditional))
820     {
821       CPP_OPTION (pfile, trigraphs) = 0;
822       CPP_OPTION (pfile, warn_trigraphs) = 0;
823     }
824 }
825