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 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 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,    1,     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,    1,     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->avoid_paste.src_loc = 0;
 252   pfile->endarg.type = CPP_EOF;
 253   pfile->endarg.flags = 0;
 254   pfile->endarg.src_loc = 0;
 255
 256   /* Create a token buffer for the lexer.  */
 257   _cpp_init_tokenrun (&pfile->base_run, 250);
 258   pfile->cur_run = &pfile->base_run;
 259   pfile->cur_token = pfile->base_run.base;
 260
 261   /* Initialize the base context.  */
 262   pfile->context = &pfile->base_context;
 263   pfile->base_context.c.macro = 0;
 264   pfile->base_context.prev = pfile->base_context.next = 0;
 265
 266   /* Aligned and unaligned storage.  */
 267   pfile->a_buff = _cpp_get_buff (pfile, 0);
 268   pfile->u_buff = _cpp_get_buff (pfile, 0);
 269
 270   /* Initialize table for push_macro/pop_macro.  */
 271   pfile->pushed_macros = 0;
 272
 273   /* Do not force token locations by default.  */
 274   pfile->forced_token_location = 0;
 275
 276   /* Note the timestamp is unset.  */
 277   pfile->time_stamp = time_t (-1);
 278   pfile->time_stamp_kind = 0;
 279
 280   /* The expression parser stack.  */
 281   _cpp_expand_op_stack (pfile);
 282
 283   /* Initialize the buffer obstack.  */
 284   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 285
 286   _cpp_init_files (pfile);
 287
 288   _cpp_init_hashtable (pfile, table);
 289
 290   return pfile;
 291 }
 292
 293 /* Set the line_table entry in PFILE.  This is called after reading a
 294    PCH file, as the old line_table will be incorrect.  */
 295 void
 296 cpp_set_line_map (cpp_reader *pfile, class line_maps *line_table)
 297 {
 298   pfile->line_table = line_table;
 299 }
 300
 301 /* Free resources used by PFILE.  Accessing PFILE after this function
 302    returns leads to undefined behavior.  Returns the error count.  */
 303 void
 304 cpp_destroy (cpp_reader *pfile)
 305 {
 306   cpp_context *context, *contextn;
 307   struct def_pragma_macro *pmacro;
 308   tokenrun *run, *runn;
 309   int i;
 310
 311   free (pfile->op_stack);
 312
 313   while (CPP_BUFFER (pfile) != NULL)
 314     _cpp_pop_buffer (pfile);
 315
 316   free (pfile->out.base);
 317
 318   if (pfile->macro_buffer)
 319     {
 320       free (pfile->macro_buffer);
 321       pfile->macro_buffer = NULL;
 322       pfile->macro_buffer_len = 0;
 323     }
 324
 325   if (pfile->deps)
 326     deps_free (pfile->deps);
 327   obstack_free (&pfile->buffer_ob, 0);
 328
 329   _cpp_destroy_hashtable (pfile);
 330   _cpp_cleanup_files (pfile);
 331   _cpp_destroy_iconv (pfile);
 332
 333   _cpp_free_buff (pfile->a_buff);
 334   _cpp_free_buff (pfile->u_buff);
 335   _cpp_free_buff (pfile->free_buffs);
 336
 337   for (run = &pfile->base_run; run; run = runn)
 338     {
 339       runn = run->next;
 340       free (run->base);
 341       if (run != &pfile->base_run)
 342         free (run);
 343     }
 344
 345   for (context = pfile->base_context.next; context; context = contextn)
 346     {
 347       contextn = context->next;
 348       free (context);
 349     }
 350
 351   if (pfile->comments.entries)
 352     {
 353       for (i = 0; i < pfile->comments.count; i++)
 354         free (pfile->comments.entries[i].comment);
 355
 356       free (pfile->comments.entries);
 357     }
 358   if (pfile->pushed_macros)
 359     {
 360       do
 361         {
 362           pmacro = pfile->pushed_macros;
 363           pfile->pushed_macros = pmacro->next;
 364           free (pmacro->name);
 365           free (pmacro);
 366         }
 367       while (pfile->pushed_macros);
 368     }
 369
 370   free (pfile);
 371 }
 372
 373 /* This structure defines one built-in identifier.  A node will be
 374    entered in the hash table under the name NAME, with value VALUE.
 375
 376    There are two tables of these.  builtin_array holds all the
 377    "builtin" macros: these are handled by builtin_macro() in
 378    macro.c.  Builtin is somewhat of a misnomer -- the property of
 379    interest is that these macros require special code to compute their
 380    expansions.  The value is a "cpp_builtin_type" enumerator.
 381
 382    operator_array holds the C++ named operators.  These are keywords
 383    which act as aliases for punctuators.  In C++, they cannot be
 384    altered through #define, and #if recognizes them as operators.  In
 385    C, these are not entered into the hash table at all (but see
 386    <iso646.h>).  The value is a token-type enumerator.  */
 387 struct builtin_macro
 388 {
 389   const uchar *const name;
 390   const unsigned short len;
 391   const unsigned short value;
 392   const bool always_warn_if_redefined;
 393 };
 394
 395 #define B(n, t, f)    { DSC(n), t, f }
 396 static const struct builtin_macro builtin_array[] =
 397 {
 398   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 399   B("__TIME__",          BT_TIME,          false),
 400   B("__DATE__",          BT_DATE,          false),
 401   B("__FILE__",          BT_FILE,          false),
 402   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 403   B("__LINE__",          BT_SPECLINE,      true),
 404   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 405   B("__COUNTER__",       BT_COUNTER,       true),
 406   /* Make sure to update the list of built-in
 407      function-like macros in traditional.c:
 408      fun_like_macro() when adding more following */
 409   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 410   B("__has_c_attribute", BT_HAS_STD_ATTRIBUTE, true),
 411   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 412   B("__has_builtin",     BT_HAS_BUILTIN,   true),
 413   B("__has_include",     BT_HAS_INCLUDE,   true),
 414   B("__has_include_next",BT_HAS_INCLUDE_NEXT,   true),
 415   /* Keep builtins not used for -traditional-cpp at the end, and
 416      update init_builtins() if any more are added.  */
 417   B("_Pragma",           BT_PRAGMA,        true),
 418   B("__STDC__",          BT_STDC,          true),
 419 };
 420 #undef B
 421
 422 struct builtin_operator
 423 {
 424   const uchar *const name;
 425   const unsigned short len;
 426   const unsigned short value;
 427 };
 428
 429 #define B(n, t)    { DSC(n), t }
 430 static const struct builtin_operator operator_array[] =
 431 {
 432   B("and",      CPP_AND_AND),
 433   B("and_eq",   CPP_AND_EQ),
 434   B("bitand",   CPP_AND),
 435   B("bitor",    CPP_OR),
 436   B("compl",    CPP_COMPL),
 437   B("not",      CPP_NOT),
 438   B("not_eq",   CPP_NOT_EQ),
 439   B("or",       CPP_OR_OR),
 440   B("or_eq",    CPP_OR_EQ),
 441   B("xor",      CPP_XOR),
 442   B("xor_eq",   CPP_XOR_EQ)
 443 };
 444 #undef B
 445
 446 /* Mark the C++ named operators in the hash table.  */
 447 static void
 448 mark_named_operators (cpp_reader *pfile, int flags)
 449 {
 450   const struct builtin_operator *b;
 451
 452   for (b = operator_array;
 453        b < (operator_array + ARRAY_SIZE (operator_array));
 454        b++)
 455     {
 456       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 457       hp->flags |= flags;
 458       hp->is_directive = 0;
 459       hp->directive_index = b->value;
 460     }
 461 }
 462
 463 /* Helper function of cpp_type2name. Return the string associated with
 464    named operator TYPE.  */
 465 const char *
 466 cpp_named_operator2name (enum cpp_ttype type)
 467 {
 468   const struct builtin_operator *b;
 469
 470   for (b = operator_array;
 471        b < (operator_array + ARRAY_SIZE (operator_array));
 472        b++)
 473     {
 474       if (type == b->value)
 475         return (const char *) b->name;
 476     }
 477
 478   return NULL;
 479 }
 480
 481 void
 482 cpp_init_special_builtins (cpp_reader *pfile)
 483 {
 484   const struct builtin_macro *b;
 485   size_t n = ARRAY_SIZE (builtin_array);
 486
 487   if (CPP_OPTION (pfile, traditional))
 488     n -= 2;
 489   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 490            || CPP_OPTION (pfile, std))
 491     n--;
 492
 493   for (b = builtin_array; b < builtin_array + n; b++)
 494     {
 495       if ((b->value == BT_HAS_ATTRIBUTE
 496            || b->value == BT_HAS_STD_ATTRIBUTE
 497            || b->value == BT_HAS_BUILTIN)
 498           && (CPP_OPTION (pfile, lang) == CLK_ASM
 499               || pfile->cb.has_attribute == NULL))
 500         continue;
 501       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 502       hp->type = NT_BUILTIN_MACRO;
 503       if (b->always_warn_if_redefined)
 504         hp->flags |= NODE_WARN;
 505       hp->value.builtin = (enum cpp_builtin_type) b->value;
 506     }
 507 }
 508
 509 /* Restore macro C to builtin macro definition.  */
 510
 511 void
 512 _cpp_restore_special_builtin (cpp_reader *pfile, struct def_pragma_macro *c)
 513 {
 514   size_t len = strlen (c->name);
 515
 516   for (const struct builtin_macro *b = builtin_array;
 517        b < builtin_array + ARRAY_SIZE (builtin_array); b++)
 518     if (b->len == len && memcmp (c->name, b->name, len + 1) == 0)
 519       {
 520         cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 521         hp->type = NT_BUILTIN_MACRO;
 522         if (b->always_warn_if_redefined)
 523           hp->flags |= NODE_WARN;
 524         hp->value.builtin = (enum cpp_builtin_type) b->value;
 525       }
 526 }
 527
 528 /* Read the builtins table above and enter them, and language-specific
 529    macros, into the hash table.  HOSTED is true if this is a hosted
 530    environment.  */
 531 void
 532 cpp_init_builtins (cpp_reader *pfile, int hosted)
 533 {
 534   cpp_init_special_builtins (pfile);
 535
 536   if (!CPP_OPTION (pfile, traditional)
 537       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 538           || CPP_OPTION (pfile, std)))
 539     _cpp_define_builtin (pfile, "__STDC__ 1");
 540
 541   if (CPP_OPTION (pfile, cplusplus))
 542     {
 543       if (CPP_OPTION (pfile, lang) == CLK_CXX20
 544           || CPP_OPTION (pfile, lang) == CLK_GNUCXX20)
 545         _cpp_define_builtin (pfile, "__cplusplus 201709L");
 546       else if (CPP_OPTION (pfile, lang) == CLK_CXX17
 547           || CPP_OPTION (pfile, lang) == CLK_GNUCXX17)
 548         _cpp_define_builtin (pfile, "__cplusplus 201703L");
 549       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 550           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 551         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 552       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 553                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 554         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 555       else
 556         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 557     }
 558   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 559     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 560   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 561     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 562   else if (CPP_OPTION (pfile, lang) == CLK_STDC2X
 563            || CPP_OPTION (pfile, lang) == CLK_GNUC2X)
 564     _cpp_define_builtin (pfile, "__STDC_VERSION__ 202000L");
 565   else if (CPP_OPTION (pfile, lang) == CLK_STDC17
 566            || CPP_OPTION (pfile, lang) == CLK_GNUC17)
 567     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201710L");
 568   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 569            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 570     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 571   else if (CPP_OPTION (pfile, c99))
 572     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 573
 574   if (CPP_OPTION (pfile, uliterals)
 575       && !(CPP_OPTION (pfile, cplusplus)
 576            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 577             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 578     {
 579       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 580       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 581     }
 582
 583   if (hosted)
 584     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 585   else
 586     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 587
 588   if (CPP_OPTION (pfile, objc))
 589     _cpp_define_builtin (pfile, "__OBJC__ 1");
 590 }
 591
 592 /* Sanity-checks are dependent on command-line options, so it is
 593    called as a subroutine of cpp_read_main_file.  */
 594 #if CHECKING_P
 595 static void sanity_checks (cpp_reader *);
 596 static void sanity_checks (cpp_reader *pfile)
 597 {
 598   cppchar_t test = 0;
 599   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 600
 601   /* Sanity checks for assumptions about CPP arithmetic and target
 602      type precisions made by cpplib.  */
 603   test--;
 604   if (test < 1)
 605     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 606
 607   if (CPP_OPTION (pfile, precision) > max_precision)
 608     cpp_error (pfile, CPP_DL_ICE,
 609                "preprocessor arithmetic has maximum precision of %lu bits;"
 610                " target requires %lu bits",
 611                (unsigned long) max_precision,
 612                (unsigned long) CPP_OPTION (pfile, precision));
 613
 614   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 615     cpp_error (pfile, CPP_DL_ICE,
 616                "CPP arithmetic must be at least as precise as a target int");
 617
 618   if (CPP_OPTION (pfile, char_precision) < 8)
 619     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 620
 621   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 622     cpp_error (pfile, CPP_DL_ICE,
 623                "target wchar_t is narrower than target char");
 624
 625   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 626     cpp_error (pfile, CPP_DL_ICE,
 627                "target int is narrower than target char");
 628
 629   /* This is assumed in eval_token() and could be fixed if necessary.  */
 630   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 631     cpp_error (pfile, CPP_DL_ICE,
 632                "CPP half-integer narrower than CPP character");
 633
 634   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 635     cpp_error (pfile, CPP_DL_ICE,
 636                "CPP on this host cannot handle wide character constants over"
 637                " %lu bits, but the target requires %lu bits",
 638                (unsigned long) BITS_PER_CPPCHAR_T,
 639                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 640 }
 641 #else
 642 # define sanity_checks(PFILE)
 643 #endif
 644
 645 /* This is called after options have been parsed, and partially
 646    processed.  */
 647 void
 648 cpp_post_options (cpp_reader *pfile)
 649 {
 650   int flags;
 651
 652   sanity_checks (pfile);
 653
 654   post_options (pfile);
 655
 656   /* Mark named operators before handling command line macros.  */
 657   flags = 0;
 658   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 659     flags |= NODE_OPERATOR;
 660   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 661     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 662   if (flags != 0)
 663     mark_named_operators (pfile, flags);
 664 }
 665
 666 /* Setup for processing input from the file named FNAME, or stdin if
 667    it is the empty string.  Return the original filename on success
 668    (e.g. foo.i->foo.c), or NULL on failure.  INJECTING is true if
 669    there may be injected headers before line 1 of the main file.  */
 670 const char *
 671 cpp_read_main_file (cpp_reader *pfile, const char *fname, bool injecting)
 672 {
 673   if (mkdeps *deps = cpp_get_deps (pfile))
 674     /* Set the default target (if there is none already).  */
 675     deps_add_default_target (deps, fname);
 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 || CPP_OPTION (pfile, preprocessed)
 685                    ? IT_PRE_MAIN : IT_MAIN, 0);
 686
 687   /* For foo.i, read the original filename foo.c now, for the benefit
 688      of the front ends.  */
 689   if (CPP_OPTION (pfile, preprocessed))
 690     if (!read_original_filename (pfile))
 691       {
 692         /* We're on line 1 after all.  */
 693         auto *last = linemap_check_ordinary
 694           (LINEMAPS_LAST_MAP (pfile->line_table, false));
 695         last->to_line = 1;
 696         /* Inform of as-if a file change.  */
 697         _cpp_do_file_change (pfile, LC_RENAME_VERBATIM, LINEMAP_FILE (last),
 698                              LINEMAP_LINE (last), LINEMAP_SYSP (last));
 699       }
 700
 701   return ORDINARY_MAP_FILE_NAME (LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table));
 702 }
 703
 704 /* For preprocessed files, if the very first characters are
 705    '#<SPACE>[01]<SPACE>', then handle a line directive so we know the
 706    original file name.  This will generate file_change callbacks,
 707    which the front ends must handle appropriately given their state of
 708    initialization.  We peek directly into the character buffer, so
 709    that we're not confused by otherwise-skipped white space &
 710    comments.  We can be very picky, because this should have been
 711    machine-generated text (by us, no less).  This way we do not
 712    interfere with the module directive state machine.  */
 713
 714 static bool
 715 read_original_filename (cpp_reader *pfile)
 716 {
 717   auto *buf = pfile->buffer->next_line;
 718
 719   if (pfile->buffer->rlimit - buf > 4
 720       && buf[0] == '#'
 721       && buf[1] == ' '
 722       // Also permit '1', as that's what used to be here
 723       && (buf[2] == '0' || buf[2] == '1')
 724       && buf[3] == ' ')
 725     {
 726       const cpp_token *token = _cpp_lex_direct (pfile);
 727       gcc_checking_assert (token->type == CPP_HASH);
 728       if (_cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 729         {
 730           read_original_directory (pfile);
 731           return true;
 732         }
 733     }
 734
 735   return false;
 736 }
 737
 738 /* For preprocessed files, if the tokens following the first filename
 739    line is of the form # <line> "/path/name//", handle the
 740    directive so we know the original current directory.
 741
 742    As with the first line peeking, we can do this without lexing by
 743    being picky.  */
 744 static void
 745 read_original_directory (cpp_reader *pfile)
 746 {
 747   auto *buf = pfile->buffer->next_line;
 748
 749   if (pfile->buffer->rlimit - buf > 4
 750       && buf[0] == '#'
 751       && buf[1] == ' '
 752       // Also permit '1', as that's what used to be here
 753       && (buf[2] == '0' || buf[2] == '1')
 754       && buf[3] == ' ')
 755     {
 756       const cpp_token *hash = _cpp_lex_direct (pfile);
 757       gcc_checking_assert (hash->type == CPP_HASH);
 758       pfile->state.in_directive = 1;
 759       const cpp_token *number = _cpp_lex_direct (pfile);
 760       gcc_checking_assert (number->type == CPP_NUMBER);
 761       const cpp_token *string = _cpp_lex_direct (pfile);
 762       pfile->state.in_directive = 0;
 763
 764       const unsigned char *text = nullptr;
 765       size_t len = 0;
 766       if (string->type == CPP_STRING)
 767         {
 768           /* The string value includes the quotes.  */
 769           text = string->val.str.text;
 770           len = string->val.str.len;
 771         }
 772       if (len < 5
 773           || !IS_DIR_SEPARATOR (text[len - 2])
 774           || !IS_DIR_SEPARATOR (text[len - 3]))
 775         {
 776           /* That didn't work out, back out.   */
 777           _cpp_backup_tokens (pfile, 3);
 778           return;
 779         }
 780
 781       if (pfile->cb.dir_change)
 782         {
 783           /* Smash the string directly, it's dead at this point  */
 784           char *smashy = (char *)text;
 785           smashy[len - 3] = 0;
 786
 787           pfile->cb.dir_change (pfile, smashy + 1);
 788         }
 789
 790       /* We should be at EOL.  */
 791     }
 792 }
 793
 794 /* This is called at the end of preprocessing.  It pops the last
 795    buffer and writes dependency output.
 796
 797    Maybe it should also reset state, such that you could call
 798    cpp_start_read with a new filename to restart processing.  */
 799 void
 800 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 801 {
 802   /* Warn about unused macros before popping the final buffer.  */
 803   if (CPP_OPTION (pfile, warn_unused_macros))
 804     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 805
 806   /* lex.c leaves the final buffer on the stack.  This it so that
 807      it returns an unending stream of CPP_EOFs to the client.  If we
 808      popped the buffer, we'd dereference a NULL buffer pointer and
 809      segfault.  It's nice to allow the client to do worry-free excess
 810      cpp_get_token calls.  */
 811   while (pfile->buffer)
 812     _cpp_pop_buffer (pfile);
 813
 814   if (deps_stream)
 815     deps_write (pfile, deps_stream, 72);
 816
 817   /* Report on headers that could use multiple include guards.  */
 818   if (CPP_OPTION (pfile, print_include_names))
 819     _cpp_report_missing_guards (pfile);
 820 }
 821
 822 static void
 823 post_options (cpp_reader *pfile)
 824 {
 825   /* -Wtraditional is not useful in C++ mode.  */
 826   if (CPP_OPTION (pfile, cplusplus))
 827     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 828
 829   /* Permanently disable macro expansion if we are rescanning
 830      preprocessed text.  Read preprocesed source in ISO mode.  */
 831   if (CPP_OPTION (pfile, preprocessed))
 832     {
 833       if (!CPP_OPTION (pfile, directives_only))
 834         pfile->state.prevent_expansion = 1;
 835       CPP_OPTION (pfile, traditional) = 0;
 836     }
 837
 838   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 839     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 840
 841   if (CPP_OPTION (pfile, traditional))
 842     {
 843       CPP_OPTION (pfile, trigraphs) = 0;
 844       CPP_OPTION (pfile, warn_trigraphs) = 0;
 845     }
 846
 847   if (CPP_OPTION (pfile, module_directives))
 848     {
 849       /* These unspellable tokens have a leading space.  */
 850       const char *const inits[spec_nodes::M_HWM]
 851         = {"export ", "module ", "import ", "__import"};
 852
 853       for (int ix = 0; ix != spec_nodes::M_HWM; ix++)
 854         {
 855           cpp_hashnode *node = cpp_lookup (pfile, UC (inits[ix]),
 856                                            strlen (inits[ix]));
 857
 858           /* Token we pass to the compiler.  */
 859           pfile->spec_nodes.n_modules[ix][1] = node;
 860
 861           if (ix != spec_nodes::M__IMPORT)
 862             /* Token we recognize when lexing, drop the trailing ' '.  */
 863             node = cpp_lookup (pfile, NODE_NAME (node), NODE_LEN (node) - 1);
 864
 865           node->flags |= NODE_MODULE;
 866           pfile->spec_nodes.n_modules[ix][0] = node;
 867         }
 868     }
 869 }