libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2021 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 bool 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 cxx23_identifiers;
  86   char std;
  87   char digraphs;
  88   char uliterals;
  89   char rliterals;
  90   char user_literals;
  91   char binary_constants;
  92   char digit_separators;
  93   char trigraphs;
  94   char utf8_char_literals;
  95   char va_opt;
  96   char scope;
  97   char dfp_constants;
  98   char size_t_literals;
  99   char elifdef;
 100 };
 101
 102 static const struct lang_flags lang_defaults[] =
 103 { /*              c99 c++ xnum xid c11 c++23 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt scope dfp szlit elifdef */
 104   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,    0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0,   0,   0 },
 105   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,    0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0,   0,   0 },
 106   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,    0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0,   0,   0 },
 107   /* GNUC17   */  { 1,  0,  1,  1,  1,  0,    0,  1,   1,   1,   0,    0,     0,     0,   0,      1,   1,     0,   0,   0 },
 108   /* GNUC2X   */  { 1,  0,  1,  1,  1,  0,    0,  1,   1,   1,   0,    1,     1,     0,   1,      1,   1,     1,   0,   1 },
 109   /* STDC89   */  { 0,  0,  0,  0,  0,  0,    1,  0,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0,   0 },
 110   /* STDC94   */  { 0,  0,  0,  0,  0,  0,    1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0,   0 },
 111   /* STDC99   */  { 1,  0,  1,  1,  0,  0,    1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0,   0 },
 112   /* STDC11   */  { 1,  0,  1,  1,  1,  0,    1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0,   0 },
 113   /* STDC17   */  { 1,  0,  1,  1,  1,  0,    1,  1,   1,   0,   0,    0,     0,     1,   0,      0,   0,     0,   0,   0 },
 114   /* STDC2X   */  { 1,  0,  1,  1,  1,  0,    1,  1,   1,   0,   0,    1,     1,     1,   1,      0,   1,     1,   0,   1 },
 115   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,    0,  1,   0,   0,   0,    0,     0,     0,   0,      1,   1,     0,   0,   0 },
 116   /* CXX98    */  { 0,  1,  0,  1,  0,  0,    1,  1,   0,   0,   0,    0,     0,     1,   0,      0,   1,     0,   0,   0 },
 117   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,    0,  1,   1,   1,   1,    0,     0,     0,   0,      1,   1,     0,   0,   0 },
 118   /* CXX11    */  { 1,  1,  0,  1,  1,  0,    1,  1,   1,   1,   1,    0,     0,     1,   0,      0,   1,     0,   0,   0 },
 119   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,    0,  1,   1,   1,   1,    1,     1,     0,   0,      1,   1,     0,   0,   0 },
 120   /* CXX14    */  { 1,  1,  0,  1,  1,  0,    1,  1,   1,   1,   1,    1,     1,     1,   0,      0,   1,     0,   0,   0 },
 121   /* GNUCXX17 */  { 1,  1,  1,  1,  1,  0,    0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0,   0 },
 122   /* CXX17    */  { 1,  1,  1,  1,  1,  0,    1,  1,   1,   1,   1,    1,     1,     0,   1,      0,   1,     0,   0,   0 },
 123   /* GNUCXX20 */  { 1,  1,  1,  1,  1,  0,    0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0,   0 },
 124   /* CXX20    */  { 1,  1,  1,  1,  1,  0,    1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   0,   0 },
 125   /* GNUCXX23 */  { 1,  1,  1,  1,  1,  1,    0,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1,   1 },
 126   /* CXX23    */  { 1,  1,  1,  1,  1,  1,    1,  1,   1,   1,   1,    1,     1,     0,   1,      1,   1,     0,   1,   1 },
 127   /* ASM      */  { 0,  0,  1,  0,  0,  0,    0,  0,   0,   0,   0,    0,     0,     0,   0,      0,   0,     0,   0,   0 }
 128 };
 129
 130 /* Sets internal flags correctly for a given language.  */
 131 void
 132 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 133 {
 134   const struct lang_flags *l = &lang_defaults[(int) lang];
 135
 136   CPP_OPTION (pfile, lang) = lang;
 137
 138   CPP_OPTION (pfile, c99)                        = l->c99;
 139   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 140   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 141   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 142   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 143   CPP_OPTION (pfile, cxx23_identifiers)          = l->cxx23_identifiers;
 144   CPP_OPTION (pfile, std)                        = l->std;
 145   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 146   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 147   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 148   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 149   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 150   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 151   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 152   CPP_OPTION (pfile, utf8_char_literals)         = l->utf8_char_literals;
 153   CPP_OPTION (pfile, va_opt)                     = l->va_opt;
 154   CPP_OPTION (pfile, scope)                      = l->scope;
 155   CPP_OPTION (pfile, dfp_constants)              = l->dfp_constants;
 156   CPP_OPTION (pfile, size_t_literals)            = l->size_t_literals;
 157   CPP_OPTION (pfile, elifdef)                    = l->elifdef;
 158 }
 159
 160 /* Initialize library global state.  */
 161 static void
 162 init_library (void)
 163 {
 164   static int initialized = 0;
 165
 166   if (! initialized)
 167     {
 168       initialized = 1;
 169
 170       _cpp_init_lexer ();
 171
 172       /* Set up the trigraph map.  This doesn't need to do anything if
 173          we were compiled with a compiler that supports C99 designated
 174          initializers.  */
 175       init_trigraph_map ();
 176
 177 #ifdef ENABLE_NLS
 178        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 179 #endif
 180     }
 181 }
 182
 183 /* Initialize a cpp_reader structure.  */
 184 cpp_reader *
 185 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 186                    class line_maps *line_table)
 187 {
 188   cpp_reader *pfile;
 189
 190   /* Initialize this instance of the library if it hasn't been already.  */
 191   init_library ();
 192
 193   pfile = XCNEW (cpp_reader);
 194   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 195
 196   cpp_set_lang (pfile, lang);
 197   CPP_OPTION (pfile, warn_multichar) = 1;
 198   CPP_OPTION (pfile, discard_comments) = 1;
 199   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 200   CPP_OPTION (pfile, max_include_depth) = 200;
 201   CPP_OPTION (pfile, operator_names) = 1;
 202   CPP_OPTION (pfile, warn_trigraphs) = 2;
 203   CPP_OPTION (pfile, warn_endif_labels) = 1;
 204   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 205   CPP_OPTION (pfile, cpp_warn_c11_c2x_compat) = -1;
 206   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 207   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 208   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 209   CPP_OPTION (pfile, dollars_in_ident) = 1;
 210   CPP_OPTION (pfile, warn_dollars) = 1;
 211   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 212   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 213   CPP_OPTION (pfile, cpp_warn_implicit_fallthrough) = 0;
 214   /* By default, track locations of tokens resulting from macro
 215      expansion.  The '2' means, track the locations with the highest
 216      accuracy.  Read the comments for struct
 217      cpp_options::track_macro_expansion to learn about the other
 218      values.  */
 219   CPP_OPTION (pfile, track_macro_expansion) = 2;
 220   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 221   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 222   CPP_OPTION (pfile, canonical_system_headers)
 223       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 224   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 225   CPP_OPTION (pfile, warn_date_time) = 0;
 226
 227   /* Default CPP arithmetic to something sensible for the host for the
 228      benefit of dumb users like fix-header.  */
 229   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 230   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 231   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 232   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 233   CPP_OPTION (pfile, unsigned_char) = 0;
 234   CPP_OPTION (pfile, unsigned_wchar) = 1;
 235   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 236
 237   /* Default to no charset conversion.  */
 238   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 239   CPP_OPTION (pfile, wide_charset) = 0;
 240
 241   /* Default the input character set to UTF-8.  */
 242   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 243
 244   /* A fake empty "directory" used as the starting point for files
 245      looked up without a search path.  Name cannot be '/' because we
 246      don't want to prepend anything at all to filenames using it.  All
 247      other entries are correct zero-initialized.  */
 248   pfile->no_search_path.name = (char *) "";
 249
 250   /* Initialize the line map.  */
 251   pfile->line_table = line_table;
 252
 253   /* Initialize lexer state.  */
 254   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 255
 256   /* Set up static tokens.  */
 257   pfile->avoid_paste.type = CPP_PADDING;
 258   pfile->avoid_paste.val.source = NULL;
 259   pfile->avoid_paste.src_loc = 0;
 260   pfile->endarg.type = CPP_EOF;
 261   pfile->endarg.flags = 0;
 262   pfile->endarg.src_loc = 0;
 263
 264   /* Create a token buffer for the lexer.  */
 265   _cpp_init_tokenrun (&pfile->base_run, 250);
 266   pfile->cur_run = &pfile->base_run;
 267   pfile->cur_token = pfile->base_run.base;
 268
 269   /* Initialize the base context.  */
 270   pfile->context = &pfile->base_context;
 271   pfile->base_context.c.macro = 0;
 272   pfile->base_context.prev = pfile->base_context.next = 0;
 273
 274   /* Aligned and unaligned storage.  */
 275   pfile->a_buff = _cpp_get_buff (pfile, 0);
 276   pfile->u_buff = _cpp_get_buff (pfile, 0);
 277
 278   /* Initialize table for push_macro/pop_macro.  */
 279   pfile->pushed_macros = 0;
 280
 281   /* Do not force token locations by default.  */
 282   pfile->forced_token_location = 0;
 283
 284   /* Note the timestamp is unset.  */
 285   pfile->time_stamp = time_t (-1);
 286   pfile->time_stamp_kind = 0;
 287
 288   /* The expression parser stack.  */
 289   _cpp_expand_op_stack (pfile);
 290
 291   /* Initialize the buffer obstack.  */
 292   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 293
 294   _cpp_init_files (pfile);
 295
 296   _cpp_init_hashtable (pfile, table);
 297
 298   return pfile;
 299 }
 300
 301 /* Set the line_table entry in PFILE.  This is called after reading a
 302    PCH file, as the old line_table will be incorrect.  */
 303 void
 304 cpp_set_line_map (cpp_reader *pfile, class line_maps *line_table)
 305 {
 306   pfile->line_table = line_table;
 307 }
 308
 309 /* Free resources used by PFILE.  Accessing PFILE after this function
 310    returns leads to undefined behavior.  Returns the error count.  */
 311 void
 312 cpp_destroy (cpp_reader *pfile)
 313 {
 314   cpp_context *context, *contextn;
 315   struct def_pragma_macro *pmacro;
 316   tokenrun *run, *runn;
 317   int i;
 318
 319   free (pfile->op_stack);
 320
 321   while (CPP_BUFFER (pfile) != NULL)
 322     _cpp_pop_buffer (pfile);
 323
 324   free (pfile->out.base);
 325
 326   if (pfile->macro_buffer)
 327     {
 328       free (pfile->macro_buffer);
 329       pfile->macro_buffer = NULL;
 330       pfile->macro_buffer_len = 0;
 331     }
 332
 333   if (pfile->deps)
 334     deps_free (pfile->deps);
 335   obstack_free (&pfile->buffer_ob, 0);
 336
 337   _cpp_destroy_hashtable (pfile);
 338   _cpp_cleanup_files (pfile);
 339   _cpp_destroy_iconv (pfile);
 340
 341   _cpp_free_buff (pfile->a_buff);
 342   _cpp_free_buff (pfile->u_buff);
 343   _cpp_free_buff (pfile->free_buffs);
 344
 345   for (run = &pfile->base_run; run; run = runn)
 346     {
 347       runn = run->next;
 348       free (run->base);
 349       if (run != &pfile->base_run)
 350         free (run);
 351     }
 352
 353   for (context = pfile->base_context.next; context; context = contextn)
 354     {
 355       contextn = context->next;
 356       free (context);
 357     }
 358
 359   if (pfile->comments.entries)
 360     {
 361       for (i = 0; i < pfile->comments.count; i++)
 362         free (pfile->comments.entries[i].comment);
 363
 364       free (pfile->comments.entries);
 365     }
 366   if (pfile->pushed_macros)
 367     {
 368       do
 369         {
 370           pmacro = pfile->pushed_macros;
 371           pfile->pushed_macros = pmacro->next;
 372           free (pmacro->name);
 373           free (pmacro);
 374         }
 375       while (pfile->pushed_macros);
 376     }
 377
 378   free (pfile);
 379 }
 380
 381 /* This structure defines one built-in identifier.  A node will be
 382    entered in the hash table under the name NAME, with value VALUE.
 383
 384    There are two tables of these.  builtin_array holds all the
 385    "builtin" macros: these are handled by builtin_macro() in
 386    macro.c.  Builtin is somewhat of a misnomer -- the property of
 387    interest is that these macros require special code to compute their
 388    expansions.  The value is a "cpp_builtin_type" enumerator.
 389
 390    operator_array holds the C++ named operators.  These are keywords
 391    which act as aliases for punctuators.  In C++, they cannot be
 392    altered through #define, and #if recognizes them as operators.  In
 393    C, these are not entered into the hash table at all (but see
 394    <iso646.h>).  The value is a token-type enumerator.  */
 395 struct builtin_macro
 396 {
 397   const uchar *const name;
 398   const unsigned short len;
 399   const unsigned short value;
 400   const bool always_warn_if_redefined;
 401 };
 402
 403 #define B(n, t, f)    { DSC(n), t, f }
 404 static const struct builtin_macro builtin_array[] =
 405 {
 406   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 407   B("__TIME__",          BT_TIME,          false),
 408   B("__DATE__",          BT_DATE,          false),
 409   B("__FILE__",          BT_FILE,          false),
 410   B("__FILE_NAME__",     BT_FILE_NAME,     false),
 411   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 412   B("__LINE__",          BT_SPECLINE,      true),
 413   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 414   B("__COUNTER__",       BT_COUNTER,       true),
 415   /* Make sure to update the list of built-in
 416      function-like macros in traditional.c:
 417      fun_like_macro() when adding more following */
 418   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 419   B("__has_c_attribute", BT_HAS_STD_ATTRIBUTE, true),
 420   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 421   B("__has_builtin",     BT_HAS_BUILTIN,   true),
 422   B("__has_include",     BT_HAS_INCLUDE,   true),
 423   B("__has_include_next",BT_HAS_INCLUDE_NEXT,   true),
 424   /* Keep builtins not used for -traditional-cpp at the end, and
 425      update init_builtins() if any more are added.  */
 426   B("_Pragma",           BT_PRAGMA,        true),
 427   B("__STDC__",          BT_STDC,          true),
 428 };
 429 #undef B
 430
 431 struct builtin_operator
 432 {
 433   const uchar *const name;
 434   const unsigned short len;
 435   const unsigned short value;
 436 };
 437
 438 #define B(n, t)    { DSC(n), t }
 439 static const struct builtin_operator operator_array[] =
 440 {
 441   B("and",      CPP_AND_AND),
 442   B("and_eq",   CPP_AND_EQ),
 443   B("bitand",   CPP_AND),
 444   B("bitor",    CPP_OR),
 445   B("compl",    CPP_COMPL),
 446   B("not",      CPP_NOT),
 447   B("not_eq",   CPP_NOT_EQ),
 448   B("or",       CPP_OR_OR),
 449   B("or_eq",    CPP_OR_EQ),
 450   B("xor",      CPP_XOR),
 451   B("xor_eq",   CPP_XOR_EQ)
 452 };
 453 #undef B
 454
 455 /* Mark the C++ named operators in the hash table.  */
 456 static void
 457 mark_named_operators (cpp_reader *pfile, int flags)
 458 {
 459   const struct builtin_operator *b;
 460
 461   for (b = operator_array;
 462        b < (operator_array + ARRAY_SIZE (operator_array));
 463        b++)
 464     {
 465       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 466       hp->flags |= flags;
 467       hp->is_directive = 0;
 468       hp->directive_index = b->value;
 469     }
 470 }
 471
 472 /* Helper function of cpp_type2name. Return the string associated with
 473    named operator TYPE.  */
 474 const char *
 475 cpp_named_operator2name (enum cpp_ttype type)
 476 {
 477   const struct builtin_operator *b;
 478
 479   for (b = operator_array;
 480        b < (operator_array + ARRAY_SIZE (operator_array));
 481        b++)
 482     {
 483       if (type == b->value)
 484         return (const char *) b->name;
 485     }
 486
 487   return NULL;
 488 }
 489
 490 void
 491 cpp_init_special_builtins (cpp_reader *pfile)
 492 {
 493   const struct builtin_macro *b;
 494   size_t n = ARRAY_SIZE (builtin_array);
 495
 496   if (CPP_OPTION (pfile, traditional))
 497     n -= 2;
 498   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 499            || CPP_OPTION (pfile, std))
 500     n--;
 501
 502   for (b = builtin_array; b < builtin_array + n; b++)
 503     {
 504       if ((b->value == BT_HAS_ATTRIBUTE
 505            || b->value == BT_HAS_STD_ATTRIBUTE
 506            || b->value == BT_HAS_BUILTIN)
 507           && (CPP_OPTION (pfile, lang) == CLK_ASM
 508               || pfile->cb.has_attribute == NULL))
 509         continue;
 510       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 511       hp->type = NT_BUILTIN_MACRO;
 512       if (b->always_warn_if_redefined)
 513         hp->flags |= NODE_WARN;
 514       hp->value.builtin = (enum cpp_builtin_type) b->value;
 515     }
 516 }
 517
 518 /* Restore macro C to builtin macro definition.  */
 519
 520 void
 521 _cpp_restore_special_builtin (cpp_reader *pfile, struct def_pragma_macro *c)
 522 {
 523   size_t len = strlen (c->name);
 524
 525   for (const struct builtin_macro *b = builtin_array;
 526        b < builtin_array + ARRAY_SIZE (builtin_array); b++)
 527     if (b->len == len && memcmp (c->name, b->name, len + 1) == 0)
 528       {
 529         cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 530         hp->type = NT_BUILTIN_MACRO;
 531         if (b->always_warn_if_redefined)
 532           hp->flags |= NODE_WARN;
 533         hp->value.builtin = (enum cpp_builtin_type) b->value;
 534       }
 535 }
 536
 537 /* Read the builtins table above and enter them, and language-specific
 538    macros, into the hash table.  HOSTED is true if this is a hosted
 539    environment.  */
 540 void
 541 cpp_init_builtins (cpp_reader *pfile, int hosted)
 542 {
 543   cpp_init_special_builtins (pfile);
 544
 545   if (!CPP_OPTION (pfile, traditional)
 546       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 547           || CPP_OPTION (pfile, std)))
 548     _cpp_define_builtin (pfile, "__STDC__ 1");
 549
 550   if (CPP_OPTION (pfile, cplusplus))
 551     {
 552       /* C++23 is not yet a standard.  For now, use an invalid
 553        * year/month, 202100L, which is larger than 202002L.  */
 554       if (CPP_OPTION (pfile, lang) == CLK_CXX23
 555           || CPP_OPTION (pfile, lang) == CLK_GNUCXX23)
 556         _cpp_define_builtin (pfile, "__cplusplus 202100L");
 557       else if (CPP_OPTION (pfile, lang) == CLK_CXX20
 558           || CPP_OPTION (pfile, lang) == CLK_GNUCXX20)
 559         _cpp_define_builtin (pfile, "__cplusplus 202002L");
 560       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 561           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 562         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 563       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 564           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 565         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 566       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 567                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 568         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 569       else
 570         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 571     }
 572   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 573     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 574   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 575     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 576   else if (CPP_OPTION (pfile, lang) == CLK_STDC2X
 577            || CPP_OPTION (pfile, lang) == CLK_GNUC2X)
 578     _cpp_define_builtin (pfile, "__STDC_VERSION__ 202000L");
 579   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 580            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 581     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 582   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 583            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 584     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 585   else if (CPP_OPTION (pfile, c99))
 586     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 587
 588   if (CPP_OPTION (pfile, uliterals)
 589       && !(CPP_OPTION (pfile, cplusplus)
 590            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 591             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 592     {
 593       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 594       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 595     }
 596
 597   if (hosted)
 598     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 599   else
 600     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 601
 602   if (CPP_OPTION (pfile, objc))
 603     _cpp_define_builtin (pfile, "__OBJC__ 1");
 604 }
 605
 606 /* Sanity-checks are dependent on command-line options, so it is
 607    called as a subroutine of cpp_read_main_file.  */
 608 #if CHECKING_P
 609 static void sanity_checks (cpp_reader *);
 610 static void sanity_checks (cpp_reader *pfile)
 611 {
 612   cppchar_t test = 0;
 613   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 614
 615   /* Sanity checks for assumptions about CPP arithmetic and target
 616      type precisions made by cpplib.  */
 617   test--;
 618   if (test < 1)
 619     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 620
 621   if (CPP_OPTION (pfile, precision) > max_precision)
 622     cpp_error (pfile, CPP_DL_ICE,
 623                "preprocessor arithmetic has maximum precision of %lu bits;"
 624                " target requires %lu bits",
 625                (unsigned long) max_precision,
 626                (unsigned long) CPP_OPTION (pfile, precision));
 627
 628   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 629     cpp_error (pfile, CPP_DL_ICE,
 630                "CPP arithmetic must be at least as precise as a target int");
 631
 632   if (CPP_OPTION (pfile, char_precision) < 8)
 633     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 634
 635   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 636     cpp_error (pfile, CPP_DL_ICE,
 637                "target wchar_t is narrower than target char");
 638
 639   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 640     cpp_error (pfile, CPP_DL_ICE,
 641                "target int is narrower than target char");
 642
 643   /* This is assumed in eval_token() and could be fixed if necessary.  */
 644   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 645     cpp_error (pfile, CPP_DL_ICE,
 646                "CPP half-integer narrower than CPP character");
 647
 648   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 649     cpp_error (pfile, CPP_DL_ICE,
 650                "CPP on this host cannot handle wide character constants over"
 651                " %lu bits, but the target requires %lu bits",
 652                (unsigned long) BITS_PER_CPPCHAR_T,
 653                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 654 }
 655 #else
 656 # define sanity_checks(PFILE)
 657 #endif
 658
 659 /* This is called after options have been parsed, and partially
 660    processed.  */
 661 void
 662 cpp_post_options (cpp_reader *pfile)
 663 {
 664   int flags;
 665
 666   sanity_checks (pfile);
 667
 668   post_options (pfile);
 669
 670   /* Mark named operators before handling command line macros.  */
 671   flags = 0;
 672   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 673     flags |= NODE_OPERATOR;
 674   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 675     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 676   if (flags != 0)
 677     mark_named_operators (pfile, flags);
 678 }
 679
 680 /* Setup for processing input from the file named FNAME, or stdin if
 681    it is the empty string.  Return the original filename on success
 682    (e.g. foo.i->foo.c), or NULL on failure.  INJECTING is true if
 683    there may be injected headers before line 1 of the main file.  */
 684 const char *
 685 cpp_read_main_file (cpp_reader *pfile, const char *fname, bool injecting)
 686 {
 687   if (mkdeps *deps = cpp_get_deps (pfile))
 688     /* Set the default target (if there is none already).  */
 689     deps_add_default_target (deps, fname);
 690
 691   pfile->main_file
 692     = _cpp_find_file (pfile, fname,
 693                       CPP_OPTION (pfile, preprocessed) ? &pfile->no_search_path
 694                       : CPP_OPTION (pfile, main_search) == CMS_user
 695                       ? pfile->quote_include
 696                       : CPP_OPTION (pfile, main_search) == CMS_system
 697                       ? pfile->bracket_include : &pfile->no_search_path,
 698                       /*angle=*/0, _cpp_FFK_NORMAL, 0);
 699
 700   if (_cpp_find_failed (pfile->main_file))
 701     return NULL;
 702
 703   _cpp_stack_file (pfile, pfile->main_file,
 704                    injecting || CPP_OPTION (pfile, preprocessed)
 705                    ? IT_PRE_MAIN : IT_MAIN, 0);
 706
 707   /* For foo.i, read the original filename foo.c now, for the benefit
 708      of the front ends.  */
 709   if (CPP_OPTION (pfile, preprocessed))
 710     if (!read_original_filename (pfile))
 711       {
 712         /* We're on line 1 after all.  */
 713         auto *last = linemap_check_ordinary
 714           (LINEMAPS_LAST_MAP (pfile->line_table, false));
 715         last->to_line = 1;
 716         /* Inform of as-if a file change.  */
 717         _cpp_do_file_change (pfile, LC_RENAME_VERBATIM, LINEMAP_FILE (last),
 718                              LINEMAP_LINE (last), LINEMAP_SYSP (last));
 719       }
 720
 721   auto *map = LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table);
 722   pfile->main_loc = MAP_START_LOCATION (map);
 723
 724   return ORDINARY_MAP_FILE_NAME (map);
 725 }
 726
 727 location_t
 728 cpp_main_loc (const cpp_reader *pfile)
 729 {
 730   return pfile->main_loc;
 731 }
 732
 733 /* For preprocessed files, if the very first characters are
 734    '#<SPACE>[01]<SPACE>', then handle a line directive so we know the
 735    original file name.  This will generate file_change callbacks,
 736    which the front ends must handle appropriately given their state of
 737    initialization.  We peek directly into the character buffer, so
 738    that we're not confused by otherwise-skipped white space &
 739    comments.  We can be very picky, because this should have been
 740    machine-generated text (by us, no less).  This way we do not
 741    interfere with the module directive state machine.  */
 742
 743 static bool
 744 read_original_filename (cpp_reader *pfile)
 745 {
 746   auto *buf = pfile->buffer->next_line;
 747
 748   if (pfile->buffer->rlimit - buf > 4
 749       && buf[0] == '#'
 750       && buf[1] == ' '
 751       // Also permit '1', as that's what used to be here
 752       && (buf[2] == '0' || buf[2] == '1')
 753       && buf[3] == ' ')
 754     {
 755       const cpp_token *token = _cpp_lex_direct (pfile);
 756       gcc_checking_assert (token->type == CPP_HASH);
 757       if (_cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 758         {
 759           read_original_directory (pfile);
 760
 761           auto *penult = &linemap_check_ordinary
 762             (LINEMAPS_LAST_MAP (pfile->line_table, false))[-1];
 763           if (penult[1].reason == LC_RENAME_VERBATIM)
 764             {
 765               /* Expunge any evidence of the original linemap.  */
 766               pfile->line_table->highest_location
 767                 = pfile->line_table->highest_line
 768                 = penult[0].start_location;
 769
 770               penult[1].start_location = penult[0].start_location;
 771               penult[1].reason = penult[0].reason;
 772               penult[0] = penult[1];
 773               pfile->line_table->info_ordinary.used--;
 774               pfile->line_table->info_ordinary.cache = 0;
 775             }
 776
 777           return true;
 778         }
 779     }
 780
 781   return false;
 782 }
 783
 784 /* For preprocessed files, if the tokens following the first filename
 785    line is of the form # <line> "/path/name//", handle the
 786    directive so we know the original current directory.
 787
 788    As with the first line peeking, we can do this without lexing by
 789    being picky.  */
 790 static void
 791 read_original_directory (cpp_reader *pfile)
 792 {
 793   auto *buf = pfile->buffer->next_line;
 794
 795   if (pfile->buffer->rlimit - buf > 4
 796       && buf[0] == '#'
 797       && buf[1] == ' '
 798       // Also permit '1', as that's what used to be here
 799       && (buf[2] == '0' || buf[2] == '1')
 800       && buf[3] == ' ')
 801     {
 802       const cpp_token *hash = _cpp_lex_direct (pfile);
 803       gcc_checking_assert (hash->type == CPP_HASH);
 804       pfile->state.in_directive = 1;
 805       const cpp_token *number = _cpp_lex_direct (pfile);
 806       gcc_checking_assert (number->type == CPP_NUMBER);
 807       const cpp_token *string = _cpp_lex_direct (pfile);
 808       pfile->state.in_directive = 0;
 809
 810       const unsigned char *text = nullptr;
 811       size_t len = 0;
 812       if (string->type == CPP_STRING)
 813         {
 814           /* The string value includes the quotes.  */
 815           text = string->val.str.text;
 816           len = string->val.str.len;
 817         }
 818       if (len < 5
 819           || !IS_DIR_SEPARATOR (text[len - 2])
 820           || !IS_DIR_SEPARATOR (text[len - 3]))
 821         {
 822           /* That didn't work out, back out.   */
 823           _cpp_backup_tokens (pfile, 3);
 824           return;
 825         }
 826
 827       if (pfile->cb.dir_change)
 828         {
 829           /* Smash the string directly, it's dead at this point  */
 830           char *smashy = (char *)text;
 831           smashy[len - 3] = 0;
 832
 833           pfile->cb.dir_change (pfile, smashy + 1);
 834         }
 835
 836       /* We should be at EOL.  */
 837     }
 838 }
 839
 840 /* This is called at the end of preprocessing.  It pops the last
 841    buffer and writes dependency output.
 842
 843    Maybe it should also reset state, such that you could call
 844    cpp_start_read with a new filename to restart processing.  */
 845 void
 846 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 847 {
 848   /* Warn about unused macros before popping the final buffer.  */
 849   if (CPP_OPTION (pfile, warn_unused_macros))
 850     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 851
 852   /* lex.c leaves the final buffer on the stack.  This it so that
 853      it returns an unending stream of CPP_EOFs to the client.  If we
 854      popped the buffer, we'd dereference a NULL buffer pointer and
 855      segfault.  It's nice to allow the client to do worry-free excess
 856      cpp_get_token calls.  */
 857   while (pfile->buffer)
 858     _cpp_pop_buffer (pfile);
 859
 860   if (deps_stream)
 861     deps_write (pfile, deps_stream, 72);
 862
 863   /* Report on headers that could use multiple include guards.  */
 864   if (CPP_OPTION (pfile, print_include_names))
 865     _cpp_report_missing_guards (pfile);
 866 }
 867
 868 static void
 869 post_options (cpp_reader *pfile)
 870 {
 871   /* -Wtraditional is not useful in C++ mode.  */
 872   if (CPP_OPTION (pfile, cplusplus))
 873     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 874
 875   /* Permanently disable macro expansion if we are rescanning
 876      preprocessed text.  Read preprocesed source in ISO mode.  */
 877   if (CPP_OPTION (pfile, preprocessed))
 878     {
 879       if (!CPP_OPTION (pfile, directives_only))
 880         pfile->state.prevent_expansion = 1;
 881       CPP_OPTION (pfile, traditional) = 0;
 882     }
 883
 884   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 885     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 886
 887   if (CPP_OPTION (pfile, traditional))
 888     {
 889       CPP_OPTION (pfile, trigraphs) = 0;
 890       CPP_OPTION (pfile, warn_trigraphs) = 0;
 891     }
 892
 893   if (CPP_OPTION (pfile, module_directives))
 894     {
 895       /* These unspellable tokens have a leading space.  */
 896       const char *const inits[spec_nodes::M_HWM]
 897         = {"export ", "module ", "import ", "__import"};
 898
 899       for (int ix = 0; ix != spec_nodes::M_HWM; ix++)
 900         {
 901           cpp_hashnode *node = cpp_lookup (pfile, UC (inits[ix]),
 902                                            strlen (inits[ix]));
 903
 904           /* Token we pass to the compiler.  */
 905           pfile->spec_nodes.n_modules[ix][1] = node;
 906
 907           if (ix != spec_nodes::M__IMPORT)
 908             /* Token we recognize when lexing, drop the trailing ' '.  */
 909             node = cpp_lookup (pfile, NODE_NAME (node), NODE_LEN (node) - 1);
 910
 911           node->flags |= NODE_MODULE;
 912           pfile->spec_nodes.n_modules[ix][0] = node;
 913         }
 914     }
 915 }