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, operator_names) = 1;
 194   CPP_OPTION (pfile, warn_trigraphs) = 2;
 195   CPP_OPTION (pfile, warn_endif_labels) = 1;
 196   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 197   CPP_OPTION (pfile, cpp_warn_c11_c2x_compat) = -1;
 198   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 199   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 200   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 201   CPP_OPTION (pfile, dollars_in_ident) = 1;
 202   CPP_OPTION (pfile, warn_dollars) = 1;
 203   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 204   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 205   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
 206   /* By default, track locations of tokens resulting from macro
 207      expansion.  The '2' means, track the locations with the highest
 208      accuracy.  Read the comments for struct
 209      cpp_options::track_macro_expansion to learn about the other
 210      values.  */
 211   CPP_OPTION (pfile, track_macro_expansion) = 2;
 212   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 213   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 214   CPP_OPTION (pfile, canonical_system_headers)
 215       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 216   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 217   CPP_OPTION (pfile, warn_date_time) = 0;
 218
 219   /* Default CPP arithmetic to something sensible for the host for the
 220      benefit of dumb users like fix-header.  */
 221   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 222   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 223   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 224   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 225   CPP_OPTION (pfile, unsigned_char) = 0;
 226   CPP_OPTION (pfile, unsigned_wchar) = 1;
 227   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 228
 229   /* Default to no charset conversion.  */
 230   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 231   CPP_OPTION (pfile, wide_charset) = 0;
 232
 233   /* Default the input character set to UTF-8.  */
 234   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 235
 236   /* A fake empty "directory" used as the starting point for files
 237      looked up without a search path.  Name cannot be '/' because we
 238      don't want to prepend anything at all to filenames using it.  All
 239      other entries are correct zero-initialized.  */
 240   pfile->no_search_path.name = (char *) "";
 241
 242   /* Initialize the line map.  */
 243   pfile->line_table = line_table;
 244
 245   /* Initialize lexer state.  */
 246   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 247
 248   /* Set up static tokens.  */
 249   pfile->avoid_paste.type = CPP_PADDING;
 250   pfile->avoid_paste.val.source = NULL;
 251   pfile->eof.type = CPP_EOF;
 252   pfile->eof.flags = 0;
 253
 254   /* Create a token buffer for the lexer.  */
 255   _cpp_init_tokenrun (&pfile->base_run, 250);
 256   pfile->cur_run = &pfile->base_run;
 257   pfile->cur_token = pfile->base_run.base;
 258
 259   /* Initialize the base context.  */
 260   pfile->context = &pfile->base_context;
 261   pfile->base_context.c.macro = 0;
 262   pfile->base_context.prev = pfile->base_context.next = 0;
 263
 264   /* Aligned and unaligned storage.  */
 265   pfile->a_buff = _cpp_get_buff (pfile, 0);
 266   pfile->u_buff = _cpp_get_buff (pfile, 0);
 267
 268   /* Initialize table for push_macro/pop_macro.  */
 269   pfile->pushed_macros = 0;
 270
 271   /* Do not force token locations by default.  */
 272   pfile->forced_token_location = 0;
 273
 274   /* Initialize source_date_epoch to -2 (not yet set).  */
 275   pfile->source_date_epoch = (time_t) -2;
 276
 277   /* The expression parser stack.  */
 278   _cpp_expand_op_stack (pfile);
 279
 280   /* Initialize the buffer obstack.  */
 281   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 282
 283   _cpp_init_files (pfile);
 284
 285   _cpp_init_hashtable (pfile, table);
 286
 287   return pfile;
 288 }
 289
 290 /* Set the line_table entry in PFILE.  This is called after reading a
 291    PCH file, as the old line_table will be incorrect.  */
 292 void
 293 cpp_set_line_map (cpp_reader *pfile, class line_maps *line_table)
 294 {
 295   pfile->line_table = line_table;
 296 }
 297
 298 /* Free resources used by PFILE.  Accessing PFILE after this function
 299    returns leads to undefined behavior.  Returns the error count.  */
 300 void
 301 cpp_destroy (cpp_reader *pfile)
 302 {
 303   cpp_context *context, *contextn;
 304   struct def_pragma_macro *pmacro;
 305   tokenrun *run, *runn;
 306   int i;
 307
 308   free (pfile->op_stack);
 309
 310   while (CPP_BUFFER (pfile) != NULL)
 311     _cpp_pop_buffer (pfile);
 312
 313   free (pfile->out.base);
 314
 315   if (pfile->macro_buffer)
 316     {
 317       free (pfile->macro_buffer);
 318       pfile->macro_buffer = NULL;
 319       pfile->macro_buffer_len = 0;
 320     }
 321
 322   if (pfile->deps)
 323     deps_free (pfile->deps);
 324   obstack_free (&pfile->buffer_ob, 0);
 325
 326   _cpp_destroy_hashtable (pfile);
 327   _cpp_cleanup_files (pfile);
 328   _cpp_destroy_iconv (pfile);
 329
 330   _cpp_free_buff (pfile->a_buff);
 331   _cpp_free_buff (pfile->u_buff);
 332   _cpp_free_buff (pfile->free_buffs);
 333
 334   for (run = &pfile->base_run; run; run = runn)
 335     {
 336       runn = run->next;
 337       free (run->base);
 338       if (run != &pfile->base_run)
 339         free (run);
 340     }
 341
 342   for (context = pfile->base_context.next; context; context = contextn)
 343     {
 344       contextn = context->next;
 345       free (context);
 346     }
 347
 348   if (pfile->comments.entries)
 349     {
 350       for (i = 0; i < pfile->comments.count; i++)
 351         free (pfile->comments.entries[i].comment);
 352
 353       free (pfile->comments.entries);
 354     }
 355   if (pfile->pushed_macros)
 356     {
 357       do
 358         {
 359           pmacro = pfile->pushed_macros;
 360           pfile->pushed_macros = pmacro->next;
 361           free (pmacro->name);
 362           free (pmacro);
 363         }
 364       while (pfile->pushed_macros);
 365     }
 366
 367   free (pfile);
 368 }
 369
 370 /* This structure defines one built-in identifier.  A node will be
 371    entered in the hash table under the name NAME, with value VALUE.
 372
 373    There are two tables of these.  builtin_array holds all the
 374    "builtin" macros: these are handled by builtin_macro() in
 375    macro.c.  Builtin is somewhat of a misnomer -- the property of
 376    interest is that these macros require special code to compute their
 377    expansions.  The value is a "cpp_builtin_type" enumerator.
 378
 379    operator_array holds the C++ named operators.  These are keywords
 380    which act as aliases for punctuators.  In C++, they cannot be
 381    altered through #define, and #if recognizes them as operators.  In
 382    C, these are not entered into the hash table at all (but see
 383    <iso646.h>).  The value is a token-type enumerator.  */
 384 struct builtin_macro
 385 {
 386   const uchar *const name;
 387   const unsigned short len;
 388   const unsigned short value;
 389   const bool always_warn_if_redefined;
 390 };
 391
 392 #define B(n, t, f)    { DSC(n), t, f }
 393 static const struct builtin_macro builtin_array[] =
 394 {
 395   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 396   B("__TIME__",          BT_TIME,          false),
 397   B("__DATE__",          BT_DATE,          false),
 398   B("__FILE__",          BT_FILE,          false),
 399   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 400   B("__LINE__",          BT_SPECLINE,      true),
 401   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 402   B("__COUNTER__",       BT_COUNTER,       true),
 403   /* Make sure to update the list of built-in
 404      function-like macros in traditional.c:
 405      fun_like_macro() when adding more following */
 406   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 407   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 408   B("__has_builtin",     BT_HAS_BUILTIN,   true),
 409   B("__has_include",     BT_HAS_INCLUDE,   true),
 410   B("__has_include_next",BT_HAS_INCLUDE_NEXT,   true),
 411   /* Keep builtins not used for -traditional-cpp at the end, and
 412      update init_builtins() if any more are added.  */
 413   B("_Pragma",           BT_PRAGMA,        true),
 414   B("__STDC__",          BT_STDC,          true),
 415 };
 416 #undef B
 417
 418 struct builtin_operator
 419 {
 420   const uchar *const name;
 421   const unsigned short len;
 422   const unsigned short value;
 423 };
 424
 425 #define B(n, t)    { DSC(n), t }
 426 static const struct builtin_operator operator_array[] =
 427 {
 428   B("and",      CPP_AND_AND),
 429   B("and_eq",   CPP_AND_EQ),
 430   B("bitand",   CPP_AND),
 431   B("bitor",    CPP_OR),
 432   B("compl",    CPP_COMPL),
 433   B("not",      CPP_NOT),
 434   B("not_eq",   CPP_NOT_EQ),
 435   B("or",       CPP_OR_OR),
 436   B("or_eq",    CPP_OR_EQ),
 437   B("xor",      CPP_XOR),
 438   B("xor_eq",   CPP_XOR_EQ)
 439 };
 440 #undef B
 441
 442 /* Mark the C++ named operators in the hash table.  */
 443 static void
 444 mark_named_operators (cpp_reader *pfile, int flags)
 445 {
 446   const struct builtin_operator *b;
 447
 448   for (b = operator_array;
 449        b < (operator_array + ARRAY_SIZE (operator_array));
 450        b++)
 451     {
 452       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 453       hp->flags |= flags;
 454       hp->is_directive = 0;
 455       hp->directive_index = b->value;
 456     }
 457 }
 458
 459 /* Helper function of cpp_type2name. Return the string associated with
 460    named operator TYPE.  */
 461 const char *
 462 cpp_named_operator2name (enum cpp_ttype type)
 463 {
 464   const struct builtin_operator *b;
 465
 466   for (b = operator_array;
 467        b < (operator_array + ARRAY_SIZE (operator_array));
 468        b++)
 469     {
 470       if (type == b->value)
 471         return (const char *) b->name;
 472     }
 473
 474   return NULL;
 475 }
 476
 477 void
 478 cpp_init_special_builtins (cpp_reader *pfile)
 479 {
 480   const struct builtin_macro *b;
 481   size_t n = ARRAY_SIZE (builtin_array);
 482
 483   if (CPP_OPTION (pfile, traditional))
 484     n -= 2;
 485   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 486            || CPP_OPTION (pfile, std))
 487     n--;
 488
 489   for (b = builtin_array; b < builtin_array + n; b++)
 490     {
 491       if ((b->value == BT_HAS_ATTRIBUTE
 492            || b->value == BT_HAS_BUILTIN)
 493           && (CPP_OPTION (pfile, lang) == CLK_ASM
 494               || pfile->cb.has_attribute == NULL))
 495         continue;
 496       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 497       hp->type = NT_BUILTIN_MACRO;
 498       if (b->always_warn_if_redefined)
 499         hp->flags |= NODE_WARN;
 500       hp->value.builtin = (enum cpp_builtin_type) b->value;
 501     }
 502 }
 503
 504 /* Restore macro C to builtin macro definition.  */
 505
 506 void
 507 _cpp_restore_special_builtin (cpp_reader *pfile, struct def_pragma_macro *c)
 508 {
 509   size_t len = strlen (c->name);
 510
 511   for (const struct builtin_macro *b = builtin_array;
 512        b < builtin_array + ARRAY_SIZE (builtin_array); b++)
 513     if (b->len == len && memcmp (c->name, b->name, len + 1) == 0)
 514       {
 515         cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 516         hp->type = NT_BUILTIN_MACRO;
 517         if (b->always_warn_if_redefined)
 518           hp->flags |= NODE_WARN;
 519         hp->value.builtin = (enum cpp_builtin_type) b->value;
 520       }
 521 }
 522
 523 /* Read the builtins table above and enter them, and language-specific
 524    macros, into the hash table.  HOSTED is true if this is a hosted
 525    environment.  */
 526 void
 527 cpp_init_builtins (cpp_reader *pfile, int hosted)
 528 {
 529   cpp_init_special_builtins (pfile);
 530
 531   if (!CPP_OPTION (pfile, traditional)
 532       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 533           || CPP_OPTION (pfile, std)))
 534     _cpp_define_builtin (pfile, "__STDC__ 1");
 535
 536   if (CPP_OPTION (pfile, cplusplus))
 537     {
 538       if (CPP_OPTION (pfile, lang) == CLK_CXX20
 539           || CPP_OPTION (pfile, lang) == CLK_GNUCXX20)
 540         _cpp_define_builtin (pfile, "__cplusplus 201709L");
 541       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 542           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 543         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 544       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 545           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 546         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 547       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 548                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 549         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 550       else
 551         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 552     }
 553   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 554     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 555   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 556     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 557   else if (CPP_OPTION (pfile, lang) == CLK_STDC2X
 558            || CPP_OPTION (pfile, lang) == CLK_GNUC2X)
 559     _cpp_define_builtin (pfile, "__STDC_VERSION__ 202000L");
 560   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 561            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 562     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 563   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 564            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 565     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 566   else if (CPP_OPTION (pfile, c99))
 567     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 568
 569   if (CPP_OPTION (pfile, uliterals)
 570       && !(CPP_OPTION (pfile, cplusplus)
 571            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 572             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 573     {
 574       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 575       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 576     }
 577
 578   if (hosted)
 579     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 580   else
 581     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 582
 583   if (CPP_OPTION (pfile, objc))
 584     _cpp_define_builtin (pfile, "__OBJC__ 1");
 585 }
 586
 587 /* Sanity-checks are dependent on command-line options, so it is
 588    called as a subroutine of cpp_read_main_file.  */
 589 #if CHECKING_P
 590 static void sanity_checks (cpp_reader *);
 591 static void sanity_checks (cpp_reader *pfile)
 592 {
 593   cppchar_t test = 0;
 594   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 595
 596   /* Sanity checks for assumptions about CPP arithmetic and target
 597      type precisions made by cpplib.  */
 598   test--;
 599   if (test < 1)
 600     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 601
 602   if (CPP_OPTION (pfile, precision) > max_precision)
 603     cpp_error (pfile, CPP_DL_ICE,
 604                "preprocessor arithmetic has maximum precision of %lu bits;"
 605                " target requires %lu bits",
 606                (unsigned long) max_precision,
 607                (unsigned long) CPP_OPTION (pfile, precision));
 608
 609   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 610     cpp_error (pfile, CPP_DL_ICE,
 611                "CPP arithmetic must be at least as precise as a target int");
 612
 613   if (CPP_OPTION (pfile, char_precision) < 8)
 614     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 615
 616   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 617     cpp_error (pfile, CPP_DL_ICE,
 618                "target wchar_t is narrower than target char");
 619
 620   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 621     cpp_error (pfile, CPP_DL_ICE,
 622                "target int is narrower than target char");
 623
 624   /* This is assumed in eval_token() and could be fixed if necessary.  */
 625   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 626     cpp_error (pfile, CPP_DL_ICE,
 627                "CPP half-integer narrower than CPP character");
 628
 629   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 630     cpp_error (pfile, CPP_DL_ICE,
 631                "CPP on this host cannot handle wide character constants over"
 632                " %lu bits, but the target requires %lu bits",
 633                (unsigned long) BITS_PER_CPPCHAR_T,
 634                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 635 }
 636 #else
 637 # define sanity_checks(PFILE)
 638 #endif
 639
 640 /* This is called after options have been parsed, and partially
 641    processed.  */
 642 void
 643 cpp_post_options (cpp_reader *pfile)
 644 {
 645   int flags;
 646
 647   sanity_checks (pfile);
 648
 649   post_options (pfile);
 650
 651   /* Mark named operators before handling command line macros.  */
 652   flags = 0;
 653   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 654     flags |= NODE_OPERATOR;
 655   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 656     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 657   if (flags != 0)
 658     mark_named_operators (pfile, flags);
 659 }
 660
 661 /* Setup for processing input from the file named FNAME, or stdin if
 662    it is the empty string.  Return the original filename on success
 663    (e.g. foo.i->foo.c), or NULL on failure.  INJECTING is true if
 664    there may be injected headers before line 1 of the main file.  */
 665 const char *
 666 cpp_read_main_file (cpp_reader *pfile, const char *fname, bool injecting)
 667 {
 668   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 669     {
 670       if (!pfile->deps)
 671         pfile->deps = deps_init ();
 672
 673       /* Set the default target (if there is none already).  */
 674       deps_add_default_target (pfile->deps, fname);
 675     }
 676
 677   pfile->main_file
 678     = _cpp_find_file (pfile, fname, &pfile->no_search_path, /*angle=*/0,
 679                       _cpp_FFK_NORMAL, 0);
 680   if (_cpp_find_failed (pfile->main_file))
 681     return NULL;
 682
 683   _cpp_stack_file (pfile, pfile->main_file,
 684                    injecting ? IT_MAIN_INJECT : IT_MAIN, 0);
 685
 686   /* For foo.i, read the original filename foo.c now, for the benefit
 687      of the front ends.  */
 688   if (CPP_OPTION (pfile, preprocessed))
 689     read_original_filename (pfile);
 690
 691   return ORDINARY_MAP_FILE_NAME (LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table));
 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 }