libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2015 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 };
  95
  96 static const struct lang_flags lang_defaults[] =
  97 { /*              c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit */
  98   /* GNUC89   */  { 0,  0,  1,  0,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0 },
  99   /* GNUC99   */  { 1,  0,  1,  1,  0,  0,  1,   1,   1,   0,    0,     0,     0,   0 },
 100   /* GNUC11   */  { 1,  0,  1,  1,  1,  0,  1,   1,   1,   0,    0,     0,     0,   0 },
 101   /* STDC89   */  { 0,  0,  0,  0,  0,  1,  0,   0,   0,   0,    0,     0,     1,   0 },
 102   /* STDC94   */  { 0,  0,  0,  0,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 103   /* STDC99   */  { 1,  0,  1,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 104   /* STDC11   */  { 1,  0,  1,  1,  1,  1,  1,   1,   0,   0,    0,     0,     1,   0 },
 105   /* GNUCXX   */  { 0,  1,  1,  1,  0,  0,  1,   0,   0,   0,    0,     0,     0,   0 },
 106   /* CXX98    */  { 0,  1,  0,  1,  0,  1,  1,   0,   0,   0,    0,     0,     1,   0 },
 107   /* GNUCXX11 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    0,     0,     0,   0 },
 108   /* CXX11    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    0,     0,     1,   0 },
 109   /* GNUCXX14 */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   0 },
 110   /* CXX14    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     1,   0 },
 111   /* GNUCXX1Z */  { 1,  1,  1,  1,  1,  0,  1,   1,   1,   1,    1,     1,     0,   1 },
 112   /* CXX1Z    */  { 1,  1,  1,  1,  1,  1,  1,   1,   1,   1,    1,     1,     0,   1 },
 113   /* ASM      */  { 0,  0,  1,  0,  0,  0,  0,   0,   0,   0,    0,     0,     0,   0 }
 114 };
 115
 116 /* Sets internal flags correctly for a given language.  */
 117 void
 118 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 119 {
 120   const struct lang_flags *l = &lang_defaults[(int) lang];
 121
 122   CPP_OPTION (pfile, lang) = lang;
 123
 124   CPP_OPTION (pfile, c99)                        = l->c99;
 125   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 126   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 127   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 128   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 129   CPP_OPTION (pfile, std)                        = l->std;
 130   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 131   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 132   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 133   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 134   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 135   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 136   CPP_OPTION (pfile, trigraphs)                  = l->trigraphs;
 137   CPP_OPTION (pfile, utf8_char_literals)         = l->utf8_char_literals;
 138 }
 139
 140 /* Initialize library global state.  */
 141 static void
 142 init_library (void)
 143 {
 144   static int initialized = 0;
 145
 146   if (! initialized)
 147     {
 148       initialized = 1;
 149
 150       _cpp_init_lexer ();
 151
 152       /* Set up the trigraph map.  This doesn't need to do anything if
 153          we were compiled with a compiler that supports C99 designated
 154          initializers.  */
 155       init_trigraph_map ();
 156
 157 #ifdef ENABLE_NLS
 158        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 159 #endif
 160     }
 161 }
 162
 163 /* Initialize a cpp_reader structure.  */
 164 cpp_reader *
 165 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 166                    struct line_maps *line_table)
 167 {
 168   cpp_reader *pfile;
 169
 170   /* Initialize this instance of the library if it hasn't been already.  */
 171   init_library ();
 172
 173   pfile = XCNEW (cpp_reader);
 174   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 175
 176   cpp_set_lang (pfile, lang);
 177   CPP_OPTION (pfile, warn_multichar) = 1;
 178   CPP_OPTION (pfile, discard_comments) = 1;
 179   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 180   CPP_OPTION (pfile, tabstop) = 8;
 181   CPP_OPTION (pfile, operator_names) = 1;
 182   CPP_OPTION (pfile, warn_trigraphs) = 2;
 183   CPP_OPTION (pfile, warn_endif_labels) = 1;
 184   CPP_OPTION (pfile, cpp_warn_c90_c99_compat) = -1;
 185   CPP_OPTION (pfile, cpp_warn_cxx11_compat) = 0;
 186   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 187   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 188   CPP_OPTION (pfile, dollars_in_ident) = 1;
 189   CPP_OPTION (pfile, warn_dollars) = 1;
 190   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 191   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 192   /* By default, track locations of tokens resulting from macro
 193      expansion.  The '2' means, track the locations with the highest
 194      accuracy.  Read the comments for struct
 195      cpp_options::track_macro_expansion to learn about the other
 196      values.  */
 197   CPP_OPTION (pfile, track_macro_expansion) = 2;
 198   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 199   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 200   CPP_OPTION (pfile, canonical_system_headers)
 201       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 202   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 203   CPP_OPTION (pfile, warn_date_time) = 0;
 204
 205   /* Default CPP arithmetic to something sensible for the host for the
 206      benefit of dumb users like fix-header.  */
 207   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 208   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 209   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 210   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 211   CPP_OPTION (pfile, unsigned_char) = 0;
 212   CPP_OPTION (pfile, unsigned_wchar) = 1;
 213   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 214
 215   /* Default to no charset conversion.  */
 216   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 217   CPP_OPTION (pfile, wide_charset) = 0;
 218
 219   /* Default the input character set to UTF-8.  */
 220   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 221
 222   /* A fake empty "directory" used as the starting point for files
 223      looked up without a search path.  Name cannot be '/' because we
 224      don't want to prepend anything at all to filenames using it.  All
 225      other entries are correct zero-initialized.  */
 226   pfile->no_search_path.name = (char *) "";
 227
 228   /* Initialize the line map.  */
 229   pfile->line_table = line_table;
 230
 231   /* Initialize lexer state.  */
 232   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 233
 234   /* Set up static tokens.  */
 235   pfile->avoid_paste.type = CPP_PADDING;
 236   pfile->avoid_paste.val.source = NULL;
 237   pfile->eof.type = CPP_EOF;
 238   pfile->eof.flags = 0;
 239
 240   /* Create a token buffer for the lexer.  */
 241   _cpp_init_tokenrun (&pfile->base_run, 250);
 242   pfile->cur_run = &pfile->base_run;
 243   pfile->cur_token = pfile->base_run.base;
 244
 245   /* Initialize the base context.  */
 246   pfile->context = &pfile->base_context;
 247   pfile->base_context.c.macro = 0;
 248   pfile->base_context.prev = pfile->base_context.next = 0;
 249
 250   /* Aligned and unaligned storage.  */
 251   pfile->a_buff = _cpp_get_buff (pfile, 0);
 252   pfile->u_buff = _cpp_get_buff (pfile, 0);
 253
 254   /* Initialize table for push_macro/pop_macro.  */
 255   pfile->pushed_macros = 0;
 256
 257   /* Do not force token locations by default.  */
 258   pfile->forced_token_location_p = NULL;
 259
 260   /* The expression parser stack.  */
 261   _cpp_expand_op_stack (pfile);
 262
 263   /* Initialize the buffer obstack.  */
 264   obstack_specify_allocation (&pfile->buffer_ob, 0, 0, xmalloc, free);
 265
 266   _cpp_init_files (pfile);
 267
 268   _cpp_init_hashtable (pfile, table);
 269
 270   return pfile;
 271 }
 272
 273 /* Set the line_table entry in PFILE.  This is called after reading a
 274    PCH file, as the old line_table will be incorrect.  */
 275 void
 276 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 277 {
 278   pfile->line_table = line_table;
 279 }
 280
 281 /* Free resources used by PFILE.  Accessing PFILE after this function
 282    returns leads to undefined behavior.  Returns the error count.  */
 283 void
 284 cpp_destroy (cpp_reader *pfile)
 285 {
 286   cpp_context *context, *contextn;
 287   struct def_pragma_macro *pmacro;
 288   tokenrun *run, *runn;
 289   int i;
 290
 291   free (pfile->op_stack);
 292
 293   while (CPP_BUFFER (pfile) != NULL)
 294     _cpp_pop_buffer (pfile);
 295
 296   free (pfile->out.base);
 297
 298   if (pfile->macro_buffer)
 299     {
 300       free (pfile->macro_buffer);
 301       pfile->macro_buffer = NULL;
 302       pfile->macro_buffer_len = 0;
 303     }
 304
 305   if (pfile->deps)
 306     deps_free (pfile->deps);
 307   obstack_free (&pfile->buffer_ob, 0);
 308
 309   _cpp_destroy_hashtable (pfile);
 310   _cpp_cleanup_files (pfile);
 311   _cpp_destroy_iconv (pfile);
 312
 313   _cpp_free_buff (pfile->a_buff);
 314   _cpp_free_buff (pfile->u_buff);
 315   _cpp_free_buff (pfile->free_buffs);
 316
 317   for (run = &pfile->base_run; run; run = runn)
 318     {
 319       runn = run->next;
 320       free (run->base);
 321       if (run != &pfile->base_run)
 322         free (run);
 323     }
 324
 325   for (context = pfile->base_context.next; context; context = contextn)
 326     {
 327       contextn = context->next;
 328       free (context);
 329     }
 330
 331   if (pfile->comments.entries)
 332     {
 333       for (i = 0; i < pfile->comments.count; i++)
 334         free (pfile->comments.entries[i].comment);
 335
 336       free (pfile->comments.entries);
 337     }
 338   if (pfile->pushed_macros)
 339     {
 340       do
 341         {
 342           pmacro = pfile->pushed_macros;
 343           pfile->pushed_macros = pmacro->next;
 344           free (pmacro->name);
 345           free (pmacro);
 346         }
 347       while (pfile->pushed_macros);
 348     }
 349
 350   free (pfile);
 351 }
 352
 353 /* This structure defines one built-in identifier.  A node will be
 354    entered in the hash table under the name NAME, with value VALUE.
 355
 356    There are two tables of these.  builtin_array holds all the
 357    "builtin" macros: these are handled by builtin_macro() in
 358    macro.c.  Builtin is somewhat of a misnomer -- the property of
 359    interest is that these macros require special code to compute their
 360    expansions.  The value is a "cpp_builtin_type" enumerator.
 361
 362    operator_array holds the C++ named operators.  These are keywords
 363    which act as aliases for punctuators.  In C++, they cannot be
 364    altered through #define, and #if recognizes them as operators.  In
 365    C, these are not entered into the hash table at all (but see
 366    <iso646.h>).  The value is a token-type enumerator.  */
 367 struct builtin_macro
 368 {
 369   const uchar *const name;
 370   const unsigned short len;
 371   const unsigned short value;
 372   const bool always_warn_if_redefined;
 373 };
 374
 375 #define B(n, t, f)    { DSC(n), t, f }
 376 static const struct builtin_macro builtin_array[] =
 377 {
 378   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 379   B("__TIME__",          BT_TIME,          false),
 380   B("__DATE__",          BT_DATE,          false),
 381   B("__FILE__",          BT_FILE,          false),
 382   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 383   B("__LINE__",          BT_SPECLINE,      true),
 384   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 385   B("__COUNTER__",       BT_COUNTER,       true),
 386   B("__has_attribute",   BT_HAS_ATTRIBUTE, true),
 387   B("__has_cpp_attribute", BT_HAS_ATTRIBUTE, true),
 388   /* Keep builtins not used for -traditional-cpp at the end, and
 389      update init_builtins() if any more are added.  */
 390   B("_Pragma",           BT_PRAGMA,        true),
 391   B("__STDC__",          BT_STDC,          true),
 392 };
 393 #undef B
 394
 395 struct builtin_operator
 396 {
 397   const uchar *const name;
 398   const unsigned short len;
 399   const unsigned short value;
 400 };
 401
 402 #define B(n, t)    { DSC(n), t }
 403 static const struct builtin_operator operator_array[] =
 404 {
 405   B("and",      CPP_AND_AND),
 406   B("and_eq",   CPP_AND_EQ),
 407   B("bitand",   CPP_AND),
 408   B("bitor",    CPP_OR),
 409   B("compl",    CPP_COMPL),
 410   B("not",      CPP_NOT),
 411   B("not_eq",   CPP_NOT_EQ),
 412   B("or",       CPP_OR_OR),
 413   B("or_eq",    CPP_OR_EQ),
 414   B("xor",      CPP_XOR),
 415   B("xor_eq",   CPP_XOR_EQ)
 416 };
 417 #undef B
 418
 419 /* Mark the C++ named operators in the hash table.  */
 420 static void
 421 mark_named_operators (cpp_reader *pfile, int flags)
 422 {
 423   const struct builtin_operator *b;
 424
 425   for (b = operator_array;
 426        b < (operator_array + ARRAY_SIZE (operator_array));
 427        b++)
 428     {
 429       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 430       hp->flags |= flags;
 431       hp->is_directive = 0;
 432       hp->directive_index = b->value;
 433     }
 434 }
 435
 436 /* Helper function of cpp_type2name. Return the string associated with
 437    named operator TYPE.  */
 438 const char *
 439 cpp_named_operator2name (enum cpp_ttype type)
 440 {
 441   const struct builtin_operator *b;
 442
 443   for (b = operator_array;
 444        b < (operator_array + ARRAY_SIZE (operator_array));
 445        b++)
 446     {
 447       if (type == b->value)
 448         return (const char *) b->name;
 449     }
 450
 451   return NULL;
 452 }
 453
 454 void
 455 cpp_init_special_builtins (cpp_reader *pfile)
 456 {
 457   const struct builtin_macro *b;
 458   size_t n = ARRAY_SIZE (builtin_array);
 459
 460   if (CPP_OPTION (pfile, traditional))
 461     n -= 2;
 462   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 463            || CPP_OPTION (pfile, std))
 464     n--;
 465
 466   for (b = builtin_array; b < builtin_array + n; b++)
 467     {
 468       if (b->value == BT_HAS_ATTRIBUTE
 469           && (CPP_OPTION (pfile, lang) == CLK_ASM
 470               || pfile->cb.has_attribute == NULL))
 471         continue;
 472       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 473       hp->type = NT_MACRO;
 474       hp->flags |= NODE_BUILTIN;
 475       if (b->always_warn_if_redefined)
 476         hp->flags |= NODE_WARN;
 477       hp->value.builtin = (enum cpp_builtin_type) b->value;
 478     }
 479 }
 480
 481 /* Read the builtins table above and enter them, and language-specific
 482    macros, into the hash table.  HOSTED is true if this is a hosted
 483    environment.  */
 484 void
 485 cpp_init_builtins (cpp_reader *pfile, int hosted)
 486 {
 487   cpp_init_special_builtins (pfile);
 488
 489   if (!CPP_OPTION (pfile, traditional)
 490       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 491           || CPP_OPTION (pfile, std)))
 492     _cpp_define_builtin (pfile, "__STDC__ 1");
 493
 494   if (CPP_OPTION (pfile, cplusplus))
 495     {
 496       if (CPP_OPTION (pfile, lang) == CLK_CXX1Z
 497           || CPP_OPTION (pfile, lang) == CLK_GNUCXX1Z)
 498         _cpp_define_builtin (pfile, "__cplusplus 201500L");
 499       else if (CPP_OPTION (pfile, lang) == CLK_CXX14
 500           || CPP_OPTION (pfile, lang) == CLK_GNUCXX14)
 501         _cpp_define_builtin (pfile, "__cplusplus 201402L");
 502       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 503                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 504         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 505       else
 506         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 507     }
 508   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 509     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 510   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 511     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 512   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 513            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 514     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 515   else if (CPP_OPTION (pfile, c99))
 516     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 517
 518   if (CPP_OPTION (pfile, uliterals)
 519       && !(CPP_OPTION (pfile, cplusplus)
 520            && (CPP_OPTION (pfile, lang) == CLK_GNUCXX
 521             || CPP_OPTION (pfile, lang) == CLK_CXX98)))
 522     {
 523       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 524       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 525     }
 526
 527   if (hosted)
 528     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 529   else
 530     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 531
 532   if (CPP_OPTION (pfile, objc))
 533     _cpp_define_builtin (pfile, "__OBJC__ 1");
 534 }
 535
 536 /* Sanity-checks are dependent on command-line options, so it is
 537    called as a subroutine of cpp_read_main_file ().  */
 538 #if ENABLE_CHECKING
 539 static void sanity_checks (cpp_reader *);
 540 static void sanity_checks (cpp_reader *pfile)
 541 {
 542   cppchar_t test = 0;
 543   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 544
 545   /* Sanity checks for assumptions about CPP arithmetic and target
 546      type precisions made by cpplib.  */
 547   test--;
 548   if (test < 1)
 549     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 550
 551   if (CPP_OPTION (pfile, precision) > max_precision)
 552     cpp_error (pfile, CPP_DL_ICE,
 553                "preprocessor arithmetic has maximum precision of %lu bits;"
 554                " target requires %lu bits",
 555                (unsigned long) max_precision,
 556                (unsigned long) CPP_OPTION (pfile, precision));
 557
 558   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 559     cpp_error (pfile, CPP_DL_ICE,
 560                "CPP arithmetic must be at least as precise as a target int");
 561
 562   if (CPP_OPTION (pfile, char_precision) < 8)
 563     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 564
 565   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 566     cpp_error (pfile, CPP_DL_ICE,
 567                "target wchar_t is narrower than target char");
 568
 569   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 570     cpp_error (pfile, CPP_DL_ICE,
 571                "target int is narrower than target char");
 572
 573   /* This is assumed in eval_token() and could be fixed if necessary.  */
 574   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 575     cpp_error (pfile, CPP_DL_ICE,
 576                "CPP half-integer narrower than CPP character");
 577
 578   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 579     cpp_error (pfile, CPP_DL_ICE,
 580                "CPP on this host cannot handle wide character constants over"
 581                " %lu bits, but the target requires %lu bits",
 582                (unsigned long) BITS_PER_CPPCHAR_T,
 583                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 584 }
 585 #else
 586 # define sanity_checks(PFILE)
 587 #endif
 588
 589 /* This is called after options have been parsed, and partially
 590    processed.  */
 591 void
 592 cpp_post_options (cpp_reader *pfile)
 593 {
 594   int flags;
 595
 596   sanity_checks (pfile);
 597
 598   post_options (pfile);
 599
 600   /* Mark named operators before handling command line macros.  */
 601   flags = 0;
 602   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 603     flags |= NODE_OPERATOR;
 604   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 605     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 606   if (flags != 0)
 607     mark_named_operators (pfile, flags);
 608 }
 609
 610 /* Setup for processing input from the file named FNAME, or stdin if
 611    it is the empty string.  Return the original filename
 612    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 613 const char *
 614 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 615 {
 616   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 617     {
 618       if (!pfile->deps)
 619         pfile->deps = deps_init ();
 620
 621       /* Set the default target (if there is none already).  */
 622       deps_add_default_target (pfile->deps, fname);
 623     }
 624
 625   pfile->main_file
 626     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false);
 627   if (_cpp_find_failed (pfile->main_file))
 628     return NULL;
 629
 630   _cpp_stack_file (pfile, pfile->main_file, false);
 631
 632   /* For foo.i, read the original filename foo.c now, for the benefit
 633      of the front ends.  */
 634   if (CPP_OPTION (pfile, preprocessed))
 635     {
 636       read_original_filename (pfile);
 637       fname =
 638         ORDINARY_MAP_FILE_NAME
 639         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 640     }
 641   return fname;
 642 }
 643
 644 /* For preprocessed files, if the first tokens are of the form # NUM.
 645    handle the directive so we know the original file name.  This will
 646    generate file_change callbacks, which the front ends must handle
 647    appropriately given their state of initialization.  */
 648 static void
 649 read_original_filename (cpp_reader *pfile)
 650 {
 651   const cpp_token *token, *token1;
 652
 653   /* Lex ahead; if the first tokens are of the form # NUM, then
 654      process the directive, otherwise back up.  */
 655   token = _cpp_lex_direct (pfile);
 656   if (token->type == CPP_HASH)
 657     {
 658       pfile->state.in_directive = 1;
 659       token1 = _cpp_lex_direct (pfile);
 660       _cpp_backup_tokens (pfile, 1);
 661       pfile->state.in_directive = 0;
 662
 663       /* If it's a #line directive, handle it.  */
 664       if (token1->type == CPP_NUMBER
 665           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 666         {
 667           read_original_directory (pfile);
 668           return;
 669         }
 670     }
 671
 672   /* Backup as if nothing happened.  */
 673   _cpp_backup_tokens (pfile, 1);
 674 }
 675
 676 /* For preprocessed files, if the tokens following the first filename
 677    line is of the form # <line> "/path/name//", handle the
 678    directive so we know the original current directory.  */
 679 static void
 680 read_original_directory (cpp_reader *pfile)
 681 {
 682   const cpp_token *hash, *token;
 683
 684   /* Lex ahead; if the first tokens are of the form # NUM, then
 685      process the directive, otherwise back up.  */
 686   hash = _cpp_lex_direct (pfile);
 687   if (hash->type != CPP_HASH)
 688     {
 689       _cpp_backup_tokens (pfile, 1);
 690       return;
 691     }
 692
 693   token = _cpp_lex_direct (pfile);
 694
 695   if (token->type != CPP_NUMBER)
 696     {
 697       _cpp_backup_tokens (pfile, 2);
 698       return;
 699     }
 700
 701   token = _cpp_lex_direct (pfile);
 702
 703   if (token->type != CPP_STRING
 704       || ! (token->val.str.len >= 5
 705             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 706             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 707     {
 708       _cpp_backup_tokens (pfile, 3);
 709       return;
 710     }
 711
 712   if (pfile->cb.dir_change)
 713     {
 714       char *debugdir = (char *) alloca (token->val.str.len - 3);
 715
 716       memcpy (debugdir, (const char *) token->val.str.text + 1,
 717               token->val.str.len - 4);
 718       debugdir[token->val.str.len - 4] = '\0';
 719
 720       pfile->cb.dir_change (pfile, debugdir);
 721     }
 722 }
 723
 724 /* This is called at the end of preprocessing.  It pops the last
 725    buffer and writes dependency output.
 726
 727    Maybe it should also reset state, such that you could call
 728    cpp_start_read with a new filename to restart processing.  */
 729 void
 730 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 731 {
 732   /* Warn about unused macros before popping the final buffer.  */
 733   if (CPP_OPTION (pfile, warn_unused_macros))
 734     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 735
 736   /* lex.c leaves the final buffer on the stack.  This it so that
 737      it returns an unending stream of CPP_EOFs to the client.  If we
 738      popped the buffer, we'd dereference a NULL buffer pointer and
 739      segfault.  It's nice to allow the client to do worry-free excess
 740      cpp_get_token calls.  */
 741   while (pfile->buffer)
 742     _cpp_pop_buffer (pfile);
 743
 744   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 745       && deps_stream)
 746     {
 747       deps_write (pfile->deps, deps_stream, 72);
 748
 749       if (CPP_OPTION (pfile, deps.phony_targets))
 750         deps_phony_targets (pfile->deps, deps_stream);
 751     }
 752
 753   /* Report on headers that could use multiple include guards.  */
 754   if (CPP_OPTION (pfile, print_include_names))
 755     _cpp_report_missing_guards (pfile);
 756 }
 757
 758 static void
 759 post_options (cpp_reader *pfile)
 760 {
 761   /* -Wtraditional is not useful in C++ mode.  */
 762   if (CPP_OPTION (pfile, cplusplus))
 763     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 764
 765   /* Permanently disable macro expansion if we are rescanning
 766      preprocessed text.  Read preprocesed source in ISO mode.  */
 767   if (CPP_OPTION (pfile, preprocessed))
 768     {
 769       if (!CPP_OPTION (pfile, directives_only))
 770         pfile->state.prevent_expansion = 1;
 771       CPP_OPTION (pfile, traditional) = 0;
 772     }
 773
 774   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 775     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 776
 777   if (CPP_OPTION (pfile, traditional))
 778     {
 779       CPP_OPTION (pfile, trigraphs) = 0;
 780       CPP_OPTION (pfile, warn_trigraphs) = 0;
 781     }
 782 }