libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2020 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   char scope;
  96   char dfp_constants;
  97 };
  98
  99 static const struct lang_flags lang_defaults[] =
 100 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt scope dfp */
 101   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0 },
 102   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
 103   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
 104   /* GNUC17   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0 },
 105   /* GNUC2X   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   1,      1,   1,     1 },
 106   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 107   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 108   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 109   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 110   /* STDC17   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0 },
 111   /* STDC2X   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   1,      0,   1,     1 },
 112   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0 },
 113   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   1,     0 },
 114   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0,      1,   1,     0 },
 115   /* CXX11    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0,      0,   1,     0 },
 116   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0,      1,   1,     0 },
 117   /* CXX14    */  { 1,  1,  0,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0,      0,   1,     0 },
 118   /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
 119   /* CXX17    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      0,   1,     0 },
 120   /* GNUCXX20 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
 121   /* CXX20    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0 },
 122   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0,      0,   0,     0 }
 123 };
 124
 125 /* Sets internal flags correctly for a given language.  */
 126 void
 127 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 128 {
 129   const struct lang_flags *l = &lang_defaults[(int) lang];
 130
 131   CPP_OPTION (pfile, lang) = lang;
 132
 133   CPP_OPTION (pfile, c99)                        = l->c99;
 134   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 135   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 136   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 137   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 138   CPP_OPTION (pfile, std)                        = l->std;
 139   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 140   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 141   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 142   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 143   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 144   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 145   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 146   CPP_OPTION (pfile, utf8_char_literals)         = l->utf8_char_literals;
 147   CPP_OPTION (pfile, va_opt)                     = l->va_opt;
 148   CPP_OPTION (pfile, scope)                      = l->scope;
 149   CPP_OPTION (pfile, dfp_constants)              = l->dfp_constants;
 150 }
 151
 152 /* Initialize library global state.  */
 153 static void
 154 init_library (void)
 155 {
 156   static int initialized = 0;
 157
 158   if (! initialized)
 159     {
 160       initialized = 1;
 161
 162       _cpp_init_lexer ();
 163
 164       /* Set up the trigraph map.  This doesn't need to do anything if
 165          we were compiled with a compiler that supports C99 designated
 166          initializers.  */
 167       init_trigraph_map ();
 168
 169 #ifdef ENABLE_NLS
 170        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 171 #endif
 172     }
 173 }
 174
 175 /* Initialize a cpp_reader structure.  */
 176 cpp_reader *
 177 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 178                    class line_maps *line_table)
 179 {
 180   cpp_reader *pfile;
 181
 182   /* Initialize this instance of the library if it hasn't been already.  */
 183   init_library ();
 184
 185   pfile = XCNEW (cpp_reader);
 186   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 187
 188   cpp_set_lang (pfile, lang);
 189   CPP_OPTION (pfile, warn_multichar) = 1;
 190   CPP_OPTION (pfile, discard_comments) = 1;
 191   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 192   CPP_OPTION (pfile, max_include_depth) = 200;
 193   CPP_OPTION (pfile, tabstop) = 8;
 194   CPP_OPTION (pfile, operator_names) = 1;
 195   CPP_OPTION (pfile, warn_trigraphs) = 2;
 196   CPP_OPTION (pfile, warn_endif_labels) = 1;
 197   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 198   CPP_OPTION (pfile, cpp_warn_c11_c2x_compat) = -1;
 199   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 200   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 201   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 202   CPP_OPTION (pfile, dollars_in_ident) = 1;
 203   CPP_OPTION (pfile, warn_dollars) = 1;
 204   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 205   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 206   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
 207   /* By default, track locations of tokens resulting from macro
 208      expansion.  The '2' means, track the locations with the highest
 209      accuracy.  Read the comments for struct
 210      cpp_options::track_macro_expansion to learn about the other
 211      values.  */
 212   CPP_OPTION (pfile, track_macro_expansion) = 2;
 213   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 214   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 215   CPP_OPTION (pfile, canonical_system_headers)
 216       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 217   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 218   CPP_OPTION (pfile, warn_date_time) = 0;
 219
 220   /* Default CPP arithmetic to something sensible for the host for the
 221      benefit of dumb users like fix-header.  */
 222   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 223   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 224   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 225   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 226   CPP_OPTION (pfile, unsigned_char) = 0;
 227   CPP_OPTION (pfile, unsigned_wchar) = 1;
 228   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 229
 230   /* Default to no charset conversion.  */
 231   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 232   CPP_OPTION (pfile, wide_charset) = 0;
 233
 234   /* Default the input character set to UTF-8.  */
 235   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 236
 237   /* A fake empty "directory" used as the starting point for files
 238      looked up without a search path.  Name cannot be '/' because we
 239      don't want to prepend anything at all to filenames using it.  All
 240      other entries are correct zero-initialized.  */
 241   pfile->no_search_path.name = (char *) "";
 242
 243   /* Initialize the line map.  */
 244   pfile->line_table = line_table;
 245
 246   /* Initialize lexer state.  */
 247   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 248
 249   /* Set up static tokens.  */
 250   pfile->avoid_paste.type = CPP_PADDING;
 251   pfile->avoid_paste.val.source = NULL;
 252   pfile->eof.type = CPP_EOF;
 253   pfile->eof.flags = 0;
 254
 255   /* Create a token buffer for the lexer.  */
 256   _cpp_init_tokenrun (&pfile->base_run, 250);
 257   pfile->cur_run = &pfile->base_run;
 258   pfile->cur_token = pfile->base_run.base;
 259
 260   /* Initialize the base context.  */
 261   pfile->context = &pfile->base_context;
 262   pfile->base_context.c.macro = 0;
 263   pfile->base_context.prev = pfile->base_context.next = 0;
 264
 265   /* Aligned and unaligned storage.  */
 266   pfile->a_buff = _cpp_get_buff (pfile, 0);
 267   pfile->u_buff = _cpp_get_buff (pfile, 0);
 268
 269   /* Initialize table for push_macro/pop_macro.  */
 270   pfile->pushed_macros = 0;
 271
 272   /* Do not force token locations by default.  */
 273   pfile->forced_token_location = 0;
 274
 275   /* Initialize source_date_epoch to -2 (not yet set).  */
 276   pfile->source_date_epoch = (time_t) -2;
 277
 278   /* The expression parser stack.  */
 279   _cpp_expand_op_stack (pfile);
 280
 281   /* Initialize the buffer obstack.  */
 282   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 283
 284   _cpp_init_files (pfile);
 285
 286   _cpp_init_hashtable (pfile, table);
 287
 288   return pfile;
 289 }
 290
 291 /* Set the line_table entry in PFILE.  This is called after reading a
 292    PCH file, as the old line_table will be incorrect.  */
 293 void
 294 cpp_set_line_map (cpp_reader *pfile, class line_maps *line_table)
 295 {
 296   pfile->line_table = line_table;
 297 }
 298
 299 /* Free resources used by PFILE.  Accessing PFILE after this function
 300    returns leads to undefined behavior.  Returns the error count.  */
 301 void
 302 cpp_destroy (cpp_reader *pfile)
 303 {
 304   cpp_context *context, *contextn;
 305   struct def_pragma_macro *pmacro;
 306   tokenrun *run, *runn;
 307   int i;
 308
 309   free (pfile->op_stack);
 310
 311   while (CPP_BUFFER (pfile) != NULL)
 312     _cpp_pop_buffer (pfile);
 313
 314   free (pfile->out.base);
 315
 316   if (pfile->macro_buffer)
 317     {
 318       free (pfile->macro_buffer);
 319       pfile->macro_buffer = NULL;
 320       pfile->macro_buffer_len = 0;
 321     }
 322
 323   if (pfile->deps)
 324     deps_free (pfile->deps);
 325   obstack_free (&pfile->buffer_ob, 0);
 326
 327   _cpp_destroy_hashtable (pfile);
 328   _cpp_cleanup_files (pfile);
 329   _cpp_destroy_iconv (pfile);
 330
 331   _cpp_free_buff (pfile->a_buff);
 332   _cpp_free_buff (pfile->u_buff);
 333   _cpp_free_buff (pfile->free_buffs);
 334
 335   for (run = &pfile->base_run; run; run = runn)
 336     {
 337       runn = run->next;
 338       free (run->base);
 339       if (run != &pfile->base_run)
 340         free (run);
 341     }
 342
 343   for (context = pfile->base_context.next; context; context = contextn)
 344     {
 345       contextn = context->next;
 346       free (context);
 347     }
 348
 349   if (pfile->comments.entries)
 350     {
 351       for (i = 0; i < pfile->comments.count; i++)
 352         free (pfile->comments.entries[i].comment);
 353
 354       free (pfile->comments.entries);
 355     }
 356   if (pfile->pushed_macros)
 357     {
 358       do
 359         {
 360           pmacro = pfile->pushed_macros;
 361           pfile->pushed_macros = pmacro->next;
 362           free (pmacro->name);
 363           free (pmacro);
 364         }
 365       while (pfile->pushed_macros);
 366     }
 367
 368   free (pfile);
 369 }
 370
 371 /* This structure defines one built-in identifier.  A node will be
 372    entered in the hash table under the name NAME, with value VALUE.
 373
 374    There are two tables of these.  builtin_array holds all the
 375    "builtin" macros: these are handled by builtin_macro() in
 376    macro.c.  Builtin is somewhat of a misnomer -- the property of
 377    interest is that these macros require special code to compute their
 378    expansions.  The value is a "cpp_builtin_type" enumerator.
 379
 380    operator_array holds the C++ named operators.  These are keywords
 381    which act as aliases for punctuators.  In C++, they cannot be
 382    altered through #define, and #if recognizes them as operators.  In
 383    C, these are not entered into the hash table at all (but see
 384    <iso646.h>).  The value is a token-type enumerator.  */
 385 struct builtin_macro
 386 {
 387   const uchar *const name;
 388   const unsigned short len;
 389   const unsigned short value;
 390   const bool always_warn_if_redefined;
 391 };
 392
 393 #define B(n, t, f)    { DSC(n), t, f }
 394 static const struct builtin_macro builtin_array[] =
 395 {
 396   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 397   B("__TIME__",          BT_TIME,          false),
 398   B("__DATE__",          BT_DATE,          false),
 399   B("__FILE__",          BT_FILE,          false),
 400   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 401   B("__LINE__",          BT_SPECLINE,      true),
 402   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 403   B("__COUNTER__",       BT_COUNTER,       true),
 404   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 405   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 406   B("__has_builtin",     BT_HAS_BUILTIN,   true),
 407   B("__has_include",     BT_HAS_INCLUDE,   true),
 408   B("__has_include_next",BT_HAS_INCLUDE_NEXT,   true),
 409   /* Keep builtins not used for -traditional-cpp at the end, and
 410      update init_builtins() if any more are added.  */
 411   B("_Pragma",           BT_PRAGMA,        true),
 412   B("__STDC__",          BT_STDC,          true),
 413 };
 414 #undef B
 415
 416 struct builtin_operator
 417 {
 418   const uchar *const name;
 419   const unsigned short len;
 420   const unsigned short value;
 421 };
 422
 423 #define B(n, t)    { DSC(n), t }
 424 static const struct builtin_operator operator_array[] =
 425 {
 426   B("and",      CPP_AND_AND),
 427   B("and_eq",   CPP_AND_EQ),
 428   B("bitand",   CPP_AND),
 429   B("bitor",    CPP_OR),
 430   B("compl",    CPP_COMPL),
 431   B("not",      CPP_NOT),
 432   B("not_eq",   CPP_NOT_EQ),
 433   B("or",       CPP_OR_OR),
 434   B("or_eq",    CPP_OR_EQ),
 435   B("xor",      CPP_XOR),
 436   B("xor_eq",   CPP_XOR_EQ)
 437 };
 438 #undef B
 439
 440 /* Mark the C++ named operators in the hash table.  */
 441 static void
 442 mark_named_operators (cpp_reader *pfile, int flags)
 443 {
 444   const struct builtin_operator *b;
 445
 446   for (b = operator_array;
 447        b < (operator_array + ARRAY_SIZE (operator_array));
 448        b++)
 449     {
 450       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 451       hp->flags |= flags;
 452       hp->is_directive = 0;
 453       hp->directive_index = b->value;
 454     }
 455 }
 456
 457 /* Helper function of cpp_type2name. Return the string associated with
 458    named operator TYPE.  */
 459 const char *
 460 cpp_named_operator2name (enum cpp_ttype type)
 461 {
 462   const struct builtin_operator *b;
 463
 464   for (b = operator_array;
 465        b < (operator_array + ARRAY_SIZE (operator_array));
 466        b++)
 467     {
 468       if (type == b->value)
 469         return (const char *) b->name;
 470     }
 471
 472   return NULL;
 473 }
 474
 475 void
 476 cpp_init_special_builtins (cpp_reader *pfile)
 477 {
 478   const struct builtin_macro *b;
 479   size_t n = ARRAY_SIZE (builtin_array);
 480
 481   if (CPP_OPTION (pfile, traditional))
 482     n -= 2;
 483   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 484            || CPP_OPTION (pfile, std))
 485     n--;
 486
 487   for (b = builtin_array; b < builtin_array + n; b++)
 488     {
 489       if ((b->value == BT_HAS_ATTRIBUTE
 490            || b->value == BT_HAS_BUILTIN)
 491           && (CPP_OPTION (pfile, lang) == CLK_ASM
 492               || pfile->cb.has_attribute == NULL))
 493         continue;
 494       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 495       hp->type = NT_BUILTIN_MACRO;
 496       if (b->always_warn_if_redefined)
 497         hp->flags |= NODE_WARN;
 498       hp->value.builtin = (enum cpp_builtin_type) b->value;
 499     }
 500 }
 501
 502 /* Restore macro C to builtin macro definition.  */
 503
 504 void
 505 _cpp_restore_special_builtin (cpp_reader *pfile, struct def_pragma_macro *c)
 506 {
 507   size_t len = strlen (c->name);
 508
 509   for (const struct builtin_macro *b = builtin_array;
 510        b < builtin_array + ARRAY_SIZE (builtin_array); b++)
 511     if (b->len == len && memcmp (c->name, b->name, len + 1) == 0)
 512       {
 513         cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 514         hp->type = NT_BUILTIN_MACRO;
 515         if (b->always_warn_if_redefined)
 516           hp->flags |= NODE_WARN;
 517         hp->value.builtin = (enum cpp_builtin_type) b->value;
 518       }
 519 }
 520
 521 /* Read the builtins table above and enter them, and language-specific
 522    macros, into the hash table.  HOSTED is true if this is a hosted
 523    environment.  */
 524 void
 525 cpp_init_builtins (cpp_reader *pfile, int hosted)
 526 {
 527   cpp_init_special_builtins (pfile);
 528
 529   if (!CPP_OPTION (pfile, traditional)
 530       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 531           || CPP_OPTION (pfile, std)))
 532     _cpp_define_builtin (pfile, "__STDC__ 1");
 533
 534   if (CPP_OPTION (pfile, cplusplus))
 535     {
 536       if (CPP_OPTION (pfile, lang) == CLK_CXX20
 537           || CPP_OPTION (pfile, lang) == CLK_GNUCXX20)
 538         _cpp_define_builtin (pfile, "__cplusplus 201709L");
 539       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 540           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 541         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 542       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 543           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 544         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 545       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 546                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 547         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 548       else
 549         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 550     }
 551   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 552     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 553   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 554     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 555   else if (CPP_OPTION (pfile, lang) == CLK_STDC2X
 556            || CPP_OPTION (pfile, lang) == CLK_GNUC2X)
 557     _cpp_define_builtin (pfile, "__STDC_VERSION__ 202000L");
 558   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 559            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 560     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 561   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 562            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 563     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 564   else if (CPP_OPTION (pfile, c99))
 565     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 566
 567   if (CPP_OPTION (pfile, uliterals)
 568       && !(CPP_OPTION (pfile, cplusplus)
 569            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 570             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 571     {
 572       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 573       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 574     }
 575
 576   if (hosted)
 577     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 578   else
 579     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 580
 581   if (CPP_OPTION (pfile, objc))
 582     _cpp_define_builtin (pfile, "__OBJC__ 1");
 583 }
 584
 585 /* Sanity-checks are dependent on command-line options, so it is
 586    called as a subroutine of cpp_read_main_file.  */
 587 #if CHECKING_P
 588 static void sanity_checks (cpp_reader *);
 589 static void sanity_checks (cpp_reader *pfile)
 590 {
 591   cppchar_t test = 0;
 592   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 593
 594   /* Sanity checks for assumptions about CPP arithmetic and target
 595      type precisions made by cpplib.  */
 596   test--;
 597   if (test < 1)
 598     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 599
 600   if (CPP_OPTION (pfile, precision) > max_precision)
 601     cpp_error (pfile, CPP_DL_ICE,
 602                "preprocessor arithmetic has maximum precision of %lu bits;"
 603                " target requires %lu bits",
 604                (unsigned long) max_precision,
 605                (unsigned long) CPP_OPTION (pfile, precision));
 606
 607   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 608     cpp_error (pfile, CPP_DL_ICE,
 609                "CPP arithmetic must be at least as precise as a target int");
 610
 611   if (CPP_OPTION (pfile, char_precision) < 8)
 612     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 613
 614   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 615     cpp_error (pfile, CPP_DL_ICE,
 616                "target wchar_t is narrower than target char");
 617
 618   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 619     cpp_error (pfile, CPP_DL_ICE,
 620                "target int is narrower than target char");
 621
 622   /* This is assumed in eval_token() and could be fixed if necessary.  */
 623   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 624     cpp_error (pfile, CPP_DL_ICE,
 625                "CPP half-integer narrower than CPP character");
 626
 627   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 628     cpp_error (pfile, CPP_DL_ICE,
 629                "CPP on this host cannot handle wide character constants over"
 630                " %lu bits, but the target requires %lu bits",
 631                (unsigned long) BITS_PER_CPPCHAR_T,
 632                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 633 }
 634 #else
 635 # define sanity_checks(PFILE)
 636 #endif
 637
 638 /* This is called after options have been parsed, and partially
 639    processed.  */
 640 void
 641 cpp_post_options (cpp_reader *pfile)
 642 {
 643   int flags;
 644
 645   sanity_checks (pfile);
 646
 647   post_options (pfile);
 648
 649   /* Mark named operators before handling command line macros.  */
 650   flags = 0;
 651   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 652     flags |= NODE_OPERATOR;
 653   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 654     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 655   if (flags != 0)
 656     mark_named_operators (pfile, flags);
 657 }
 658
 659 /* Setup for processing input from the file named FNAME, or stdin if
 660    it is the empty string.  Return the original filename
 661    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 662 const char *
 663 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 664 {
 665   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 666     {
 667       if (!pfile->deps)
 668         pfile->deps = deps_init ();
 669
 670       /* Set the default target (if there is none already).  */
 671       deps_add_default_target (pfile->deps, fname);
 672     }
 673
 674   pfile->main_file
 675     = _cpp_find_file (pfile, fname, &pfile->no_search_path, /*angle=*/0,
 676                       _cpp_FFK_NORMAL, 0);
 677   if (_cpp_find_failed (pfile->main_file))
 678     return NULL;
 679
 680   _cpp_stack_file (pfile, pfile->main_file, IT_MAIN, 0);
 681
 682   /* For foo.i, read the original filename foo.c now, for the benefit
 683      of the front ends.  */
 684   if (CPP_OPTION (pfile, preprocessed))
 685     {
 686       read_original_filename (pfile);
 687       fname =
 688         ORDINARY_MAP_FILE_NAME
 689         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 690     }
 691   return fname;
 692 }
 693
 694 /* For preprocessed files, if the first tokens are of the form # NUM.
 695    handle the directive so we know the original file name.  This will
 696    generate file_change callbacks, which the front ends must handle
 697    appropriately given their state of initialization.  */
 698 static void
 699 read_original_filename (cpp_reader *pfile)
 700 {
 701   const cpp_token *token, *token1;
 702
 703   /* Lex ahead; if the first tokens are of the form # NUM, then
 704      process the directive, otherwise back up.  */
 705   token = _cpp_lex_direct (pfile);
 706   if (token->type == CPP_HASH)
 707     {
 708       pfile->state.in_directive = 1;
 709       token1 = _cpp_lex_direct (pfile);
 710       _cpp_backup_tokens (pfile, 1);
 711       pfile->state.in_directive = 0;
 712
 713       /* If it's a #line directive, handle it.  */
 714       if (token1->type == CPP_NUMBER
 715           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 716         {
 717           read_original_directory (pfile);
 718           return;
 719         }
 720     }
 721
 722   /* Backup as if nothing happened.  */
 723   _cpp_backup_tokens (pfile, 1);
 724 }
 725
 726 /* For preprocessed files, if the tokens following the first filename
 727    line is of the form # <line> "/path/name//", handle the
 728    directive so we know the original current directory.  */
 729 static void
 730 read_original_directory (cpp_reader *pfile)
 731 {
 732   const cpp_token *hash, *token;
 733
 734   /* Lex ahead; if the first tokens are of the form # NUM, then
 735      process the directive, otherwise back up.  */
 736   hash = _cpp_lex_direct (pfile);
 737   if (hash->type != CPP_HASH)
 738     {
 739       _cpp_backup_tokens (pfile, 1);
 740       return;
 741     }
 742
 743   token = _cpp_lex_direct (pfile);
 744
 745   if (token->type != CPP_NUMBER)
 746     {
 747       _cpp_backup_tokens (pfile, 2);
 748       return;
 749     }
 750
 751   token = _cpp_lex_direct (pfile);
 752
 753   if (token->type != CPP_STRING
 754       || ! (token->val.str.len >= 5
 755             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 756             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 757     {
 758       _cpp_backup_tokens (pfile, 3);
 759       return;
 760     }
 761
 762   if (pfile->cb.dir_change)
 763     {
 764       char *debugdir = (char *) alloca (token->val.str.len - 3);
 765
 766       memcpy (debugdir, (const char *) token->val.str.text + 1,
 767               token->val.str.len - 4);
 768       debugdir[token->val.str.len - 4] = '\0';
 769
 770       pfile->cb.dir_change (pfile, debugdir);
 771     }
 772 }
 773
 774 /* This is called at the end of preprocessing.  It pops the last
 775    buffer and writes dependency output.
 776
 777    Maybe it should also reset state, such that you could call
 778    cpp_start_read with a new filename to restart processing.  */
 779 void
 780 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 781 {
 782   /* Warn about unused macros before popping the final buffer.  */
 783   if (CPP_OPTION (pfile, warn_unused_macros))
 784     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 785
 786   /* lex.c leaves the final buffer on the stack.  This it so that
 787      it returns an unending stream of CPP_EOFs to the client.  If we
 788      popped the buffer, we'd dereference a NULL buffer pointer and
 789      segfault.  It's nice to allow the client to do worry-free excess
 790      cpp_get_token calls.  */
 791   while (pfile->buffer)
 792     _cpp_pop_buffer (pfile);
 793
 794   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE && deps_stream)
 795     deps_write (pfile->deps, deps_stream,
 796                 CPP_OPTION (pfile, deps.phony_targets), 72);
 797
 798   /* Report on headers that could use multiple include guards.  */
 799   if (CPP_OPTION (pfile, print_include_names))
 800     _cpp_report_missing_guards (pfile);
 801 }
 802
 803 static void
 804 post_options (cpp_reader *pfile)
 805 {
 806   /* -Wtraditional is not useful in C++ mode.  */
 807   if (CPP_OPTION (pfile, cplusplus))
 808     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 809
 810   /* Permanently disable macro expansion if we are rescanning
 811      preprocessed text.  Read preprocesed source in ISO mode.  */
 812   if (CPP_OPTION (pfile, preprocessed))
 813     {
 814       if (!CPP_OPTION (pfile, directives_only))
 815         pfile->state.prevent_expansion = 1;
 816       CPP_OPTION (pfile, traditional) = 0;
 817     }
 818
 819   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 820     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 821
 822   if (CPP_OPTION (pfile, traditional))
 823     {
 824       CPP_OPTION (pfile, trigraphs) = 0;
 825       CPP_OPTION (pfile, warn_trigraphs) = 0;
 826     }
 827 }