libcpp/init.c

   1 /* CPP Library.
   2    Copyright (C) 1986-2014 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 cplusplus_comments;
  87   char digraphs;
  88   char uliterals;
  89   char rliterals;
  90   char user_literals;
  91   char binary_constants;
  92   char digit_separators;
  93 };
  94
  95 static const struct lang_flags lang_defaults[] =
  96 { /*              c99 c++ xnum xid c11 std  //   digr ulit rlit udlit bin_cst dig_sep */
  97   /* GNUC89   */  { 0,  0,  1,   0,  0,  0,   1,   1,   0,   0,   0,    0,      0 },
  98   /* GNUC99   */  { 1,  0,  1,   0,  0,  0,   1,   1,   1,   1,   0,    0,      0 },
  99   /* GNUC11   */  { 1,  0,  1,   0,  1,  0,   1,   1,   1,   1,   0,    0,      0 },
 100   /* STDC89   */  { 0,  0,  0,   0,  0,  1,   0,   0,   0,   0,   0,    0,      0 },
 101   /* STDC94   */  { 0,  0,  0,   0,  0,  1,   0,   1,   0,   0,   0,    0,      0 },
 102   /* STDC99   */  { 1,  0,  1,   0,  0,  1,   1,   1,   0,   0,   0,    0,      0 },
 103   /* STDC11   */  { 1,  0,  1,   0,  1,  1,   1,   1,   1,   0,   0,    0,      0 },
 104   /* GNUCXX   */  { 0,  1,  1,   0,  0,  0,   1,   1,   0,   0,   0,    0,      0 },
 105   /* CXX98    */  { 0,  1,  1,   0,  0,  1,   1,   1,   0,   0,   0,    0,      0 },
 106   /* GNUCXX11 */  { 1,  1,  1,   0,  1,  0,   1,   1,   1,   1,   1,    0,      0 },
 107   /* CXX11    */  { 1,  1,  1,   0,  1,  1,   1,   1,   1,   1,   1,    0,      0 },
 108   /* GNUCXX1Y */  { 1,  1,  1,   0,  1,  0,   1,   1,   1,   1,   1,    1,      1 },
 109   /* CXX1Y    */  { 1,  1,  1,   0,  1,  1,   1,   1,   1,   1,   1,    1,      1 },
 110   /* ASM      */  { 0,  0,  1,   0,  0,  0,   1,   0,   0,   0,   0,    0,      0 }
 111   /* xid should be 1 for GNUC99, STDC99, GNUCXX, CXX98, GNUCXX11, CXX11,
 112      GNUCXX1Y, and CXX1Y when no longer experimental (when all uses of
 113      identifiers in the compiler have been audited for correct handling
 114      of extended identifiers).  */
 115 };
 116
 117 /* Sets internal flags correctly for a given language.  */
 118 void
 119 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
 120 {
 121   const struct lang_flags *l = &lang_defaults[(int) lang];
 122
 123   CPP_OPTION (pfile, lang) = lang;
 124
 125   CPP_OPTION (pfile, c99)                        = l->c99;
 126   CPP_OPTION (pfile, cplusplus)                  = l->cplusplus;
 127   CPP_OPTION (pfile, extended_numbers)           = l->extended_numbers;
 128   CPP_OPTION (pfile, extended_identifiers)       = l->extended_identifiers;
 129   CPP_OPTION (pfile, c11_identifiers)            = l->c11_identifiers;
 130   CPP_OPTION (pfile, std)                        = l->std;
 131   CPP_OPTION (pfile, trigraphs)                  = l->std;
 132   CPP_OPTION (pfile, cplusplus_comments)         = l->cplusplus_comments;
 133   CPP_OPTION (pfile, digraphs)                   = l->digraphs;
 134   CPP_OPTION (pfile, uliterals)                  = l->uliterals;
 135   CPP_OPTION (pfile, rliterals)                  = l->rliterals;
 136   CPP_OPTION (pfile, user_literals)              = l->user_literals;
 137   CPP_OPTION (pfile, binary_constants)           = l->binary_constants;
 138   CPP_OPTION (pfile, digit_separators)           = l->digit_separators;
 139 }
 140
 141 /* Initialize library global state.  */
 142 static void
 143 init_library (void)
 144 {
 145   static int initialized = 0;
 146
 147   if (! initialized)
 148     {
 149       initialized = 1;
 150
 151       _cpp_init_lexer ();
 152
 153       /* Set up the trigraph map.  This doesn't need to do anything if
 154          we were compiled with a compiler that supports C99 designated
 155          initializers.  */
 156       init_trigraph_map ();
 157
 158 #ifdef ENABLE_NLS
 159        (void) bindtextdomain (PACKAGE, LOCALEDIR);
 160 #endif
 161     }
 162 }
 163
 164 /* Initialize a cpp_reader structure.  */
 165 cpp_reader *
 166 cpp_create_reader (enum c_lang lang, cpp_hash_table *table,
 167                    struct line_maps *line_table)
 168 {
 169   cpp_reader *pfile;
 170
 171   /* Initialize this instance of the library if it hasn't been already.  */
 172   init_library ();
 173
 174   pfile = XCNEW (cpp_reader);
 175   memset (&pfile->base_context, 0, sizeof (pfile->base_context));
 176
 177   cpp_set_lang (pfile, lang);
 178   CPP_OPTION (pfile, warn_multichar) = 1;
 179   CPP_OPTION (pfile, discard_comments) = 1;
 180   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 181   CPP_OPTION (pfile, tabstop) = 8;
 182   CPP_OPTION (pfile, operator_names) = 1;
 183   CPP_OPTION (pfile, warn_trigraphs) = 2;
 184   CPP_OPTION (pfile, warn_endif_labels) = 1;
 185   CPP_OPTION (pfile, cpp_warn_deprecated) = 1;
 186   CPP_OPTION (pfile, cpp_warn_long_long) = 0;
 187   CPP_OPTION (pfile, dollars_in_ident) = 1;
 188   CPP_OPTION (pfile, warn_dollars) = 1;
 189   CPP_OPTION (pfile, warn_variadic_macros) = 1;
 190   CPP_OPTION (pfile, warn_builtin_macro_redefined) = 1;
 191   /* By default, track locations of tokens resulting from macro
 192      expansion.  The '2' means, track the locations with the highest
 193      accuracy.  Read the comments for struct
 194      cpp_options::track_macro_expansion to learn about the other
 195      values.  */
 196   CPP_OPTION (pfile, track_macro_expansion) = 2;
 197   CPP_OPTION (pfile, warn_normalize) = normalized_C;
 198   CPP_OPTION (pfile, warn_literal_suffix) = 1;
 199   CPP_OPTION (pfile, canonical_system_headers)
 200       = ENABLE_CANONICAL_SYSTEM_HEADERS;
 201   CPP_OPTION (pfile, ext_numeric_literals) = 1;
 202   CPP_OPTION (pfile, warn_date_time) = 0;
 203
 204   /* Default CPP arithmetic to something sensible for the host for the
 205      benefit of dumb users like fix-header.  */
 206   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 207   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 208   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 209   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 210   CPP_OPTION (pfile, unsigned_char) = 0;
 211   CPP_OPTION (pfile, unsigned_wchar) = 1;
 212   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 213
 214   /* Default to no charset conversion.  */
 215   CPP_OPTION (pfile, narrow_charset) = _cpp_default_encoding ();
 216   CPP_OPTION (pfile, wide_charset) = 0;
 217
 218   /* Default the input character set to UTF-8.  */
 219   CPP_OPTION (pfile, input_charset) = _cpp_default_encoding ();
 220
 221   /* A fake empty "directory" used as the starting point for files
 222      looked up without a search path.  Name cannot be '/' because we
 223      don't want to prepend anything at all to filenames using it.  All
 224      other entries are correct zero-initialized.  */
 225   pfile->no_search_path.name = (char *) "";
 226
 227   /* Initialize the line map.  */
 228   pfile->line_table = line_table;
 229
 230   /* Initialize lexer state.  */
 231   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 232
 233   /* Set up static tokens.  */
 234   pfile->avoid_paste.type = CPP_PADDING;
 235   pfile->avoid_paste.val.source = NULL;
 236   pfile->eof.type = CPP_EOF;
 237   pfile->eof.flags = 0;
 238
 239   /* Create a token buffer for the lexer.  */
 240   _cpp_init_tokenrun (&pfile->base_run, 250);
 241   pfile->cur_run = &pfile->base_run;
 242   pfile->cur_token = pfile->base_run.base;
 243
 244   /* Initialize the base context.  */
 245   pfile->context = &pfile->base_context;
 246   pfile->base_context.c.macro = 0;
 247   pfile->base_context.prev = pfile->base_context.next = 0;
 248
 249   /* Aligned and unaligned storage.  */
 250   pfile->a_buff = _cpp_get_buff (pfile, 0);
 251   pfile->u_buff = _cpp_get_buff (pfile, 0);
 252
 253   /* Initialize table for push_macro/pop_macro.  */
 254   pfile->pushed_macros = 0;
 255
 256   /* Do not force token locations by default.  */
 257   pfile->forced_token_location_p = NULL;
 258
 259   /* The expression parser stack.  */
 260   _cpp_expand_op_stack (pfile);
 261
 262   /* Initialize the buffer obstack.  */
 263   _obstack_begin (&pfile->buffer_ob, 0, 0,
 264                   (void *(*) (long)) xmalloc,
 265                   (void (*) (void *)) free);
 266
 267   _cpp_init_files (pfile);
 268
 269   _cpp_init_hashtable (pfile, table);
 270
 271   return pfile;
 272 }
 273
 274 /* Set the line_table entry in PFILE.  This is called after reading a
 275    PCH file, as the old line_table will be incorrect.  */
 276 void
 277 cpp_set_line_map (cpp_reader *pfile, struct line_maps *line_table)
 278 {
 279   pfile->line_table = line_table;
 280 }
 281
 282 /* Free resources used by PFILE.  Accessing PFILE after this function
 283    returns leads to undefined behavior.  Returns the error count.  */
 284 void
 285 cpp_destroy (cpp_reader *pfile)
 286 {
 287   cpp_context *context, *contextn;
 288   struct def_pragma_macro *pmacro;
 289   tokenrun *run, *runn;
 290   int i;
 291
 292   free (pfile->op_stack);
 293
 294   while (CPP_BUFFER (pfile) != NULL)
 295     _cpp_pop_buffer (pfile);
 296
 297   free (pfile->out.base);
 298
 299   if (pfile->macro_buffer)
 300     {
 301       free (pfile->macro_buffer);
 302       pfile->macro_buffer = NULL;
 303       pfile->macro_buffer_len = 0;
 304     }
 305
 306   if (pfile->deps)
 307     deps_free (pfile->deps);
 308   obstack_free (&pfile->buffer_ob, 0);
 309
 310   _cpp_destroy_hashtable (pfile);
 311   _cpp_cleanup_files (pfile);
 312   _cpp_destroy_iconv (pfile);
 313
 314   _cpp_free_buff (pfile->a_buff);
 315   _cpp_free_buff (pfile->u_buff);
 316   _cpp_free_buff (pfile->free_buffs);
 317
 318   for (run = &pfile->base_run; run; run = runn)
 319     {
 320       runn = run->next;
 321       free (run->base);
 322       if (run != &pfile->base_run)
 323         free (run);
 324     }
 325
 326   for (context = pfile->base_context.next; context; context = contextn)
 327     {
 328       contextn = context->next;
 329       free (context);
 330     }
 331
 332   if (pfile->comments.entries)
 333     {
 334       for (i = 0; i < pfile->comments.count; i++)
 335         free (pfile->comments.entries[i].comment);
 336
 337       free (pfile->comments.entries);
 338     }
 339   if (pfile->pushed_macros)
 340     {
 341       do
 342         {
 343           pmacro = pfile->pushed_macros;
 344           pfile->pushed_macros = pmacro->next;
 345           free (pmacro->name);
 346           free (pmacro);
 347         }
 348       while (pfile->pushed_macros);
 349     }
 350
 351   free (pfile);
 352 }
 353
 354 /* This structure defines one built-in identifier.  A node will be
 355    entered in the hash table under the name NAME, with value VALUE.
 356
 357    There are two tables of these.  builtin_array holds all the
 358    "builtin" macros: these are handled by builtin_macro() in
 359    macro.c.  Builtin is somewhat of a misnomer -- the property of
 360    interest is that these macros require special code to compute their
 361    expansions.  The value is a "cpp_builtin_type" enumerator.
 362
 363    operator_array holds the C++ named operators.  These are keywords
 364    which act as aliases for punctuators.  In C++, they cannot be
 365    altered through #define, and #if recognizes them as operators.  In
 366    C, these are not entered into the hash table at all (but see
 367    <iso646.h>).  The value is a token-type enumerator.  */
 368 struct builtin_macro
 369 {
 370   const uchar *const name;
 371   const unsigned short len;
 372   const unsigned short value;
 373   const bool always_warn_if_redefined;
 374 };
 375
 376 #define B(n, t, f)    { DSC(n), t, f }
 377 static const struct builtin_macro builtin_array[] =
 378 {
 379   B("__TIMESTAMP__",     BT_TIMESTAMP,     false),
 380   B("__TIME__",          BT_TIME,          false),
 381   B("__DATE__",          BT_DATE,          false),
 382   B("__FILE__",          BT_FILE,          false),
 383   B("__BASE_FILE__",     BT_BASE_FILE,     false),
 384   B("__LINE__",          BT_SPECLINE,      true),
 385   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
 386   B("__COUNTER__",       BT_COUNTER,       true),
 387   /* Keep builtins not used for -traditional-cpp at the end, and
 388      update init_builtins() if any more are added.  */
 389   B("_Pragma",           BT_PRAGMA,        true),
 390   B("__STDC__",          BT_STDC,          true),
 391 };
 392 #undef B
 393
 394 struct builtin_operator
 395 {
 396   const uchar *const name;
 397   const unsigned short len;
 398   const unsigned short value;
 399 };
 400
 401 #define B(n, t)    { DSC(n), t }
 402 static const struct builtin_operator operator_array[] =
 403 {
 404   B("and",      CPP_AND_AND),
 405   B("and_eq",   CPP_AND_EQ),
 406   B("bitand",   CPP_AND),
 407   B("bitor",    CPP_OR),
 408   B("compl",    CPP_COMPL),
 409   B("not",      CPP_NOT),
 410   B("not_eq",   CPP_NOT_EQ),
 411   B("or",       CPP_OR_OR),
 412   B("or_eq",    CPP_OR_EQ),
 413   B("xor",      CPP_XOR),
 414   B("xor_eq",   CPP_XOR_EQ)
 415 };
 416 #undef B
 417
 418 /* Mark the C++ named operators in the hash table.  */
 419 static void
 420 mark_named_operators (cpp_reader *pfile, int flags)
 421 {
 422   const struct builtin_operator *b;
 423
 424   for (b = operator_array;
 425        b < (operator_array + ARRAY_SIZE (operator_array));
 426        b++)
 427     {
 428       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 429       hp->flags |= flags;
 430       hp->is_directive = 0;
 431       hp->directive_index = b->value;
 432     }
 433 }
 434
 435 /* Helper function of cpp_type2name. Return the string associated with
 436    named operator TYPE.  */
 437 const char *
 438 cpp_named_operator2name (enum cpp_ttype type)
 439 {
 440   const struct builtin_operator *b;
 441
 442   for (b = operator_array;
 443        b < (operator_array + ARRAY_SIZE (operator_array));
 444        b++)
 445     {
 446       if (type == b->value)
 447         return (const char *) b->name;
 448     }
 449
 450   return NULL;
 451 }
 452
 453 void
 454 cpp_init_special_builtins (cpp_reader *pfile)
 455 {
 456   const struct builtin_macro *b;
 457   size_t n = ARRAY_SIZE (builtin_array);
 458
 459   if (CPP_OPTION (pfile, traditional))
 460     n -= 2;
 461   else if (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 462            || CPP_OPTION (pfile, std))
 463     n--;
 464
 465   for (b = builtin_array; b < builtin_array + n; b++)
 466     {
 467       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 468       hp->type = NT_MACRO;
 469       hp->flags |= NODE_BUILTIN;
 470       if (b->always_warn_if_redefined
 471           || CPP_OPTION (pfile, warn_builtin_macro_redefined))
 472         hp->flags |= NODE_WARN;
 473       hp->value.builtin = (enum cpp_builtin_type) b->value;
 474     }
 475 }
 476
 477 /* Read the builtins table above and enter them, and language-specific
 478    macros, into the hash table.  HOSTED is true if this is a hosted
 479    environment.  */
 480 void
 481 cpp_init_builtins (cpp_reader *pfile, int hosted)
 482 {
 483   cpp_init_special_builtins (pfile);
 484
 485   if (!CPP_OPTION (pfile, traditional)
 486       && (! CPP_OPTION (pfile, stdc_0_in_system_headers)
 487           || CPP_OPTION (pfile, std)))
 488     _cpp_define_builtin (pfile, "__STDC__ 1");
 489
 490   if (CPP_OPTION (pfile, cplusplus))
 491     {
 492       if (CPP_OPTION (pfile, lang) == CLK_CXX1Y
 493           || CPP_OPTION (pfile, lang) == CLK_GNUCXX1Y)
 494         _cpp_define_builtin (pfile, "__cplusplus 201300L");
 495       else if (CPP_OPTION (pfile, lang) == CLK_CXX11
 496                || CPP_OPTION (pfile, lang) == CLK_GNUCXX11)
 497         _cpp_define_builtin (pfile, "__cplusplus 201103L");
 498       else
 499         _cpp_define_builtin (pfile, "__cplusplus 199711L");
 500     }
 501   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 502     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 503   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 504     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 505   else if (CPP_OPTION (pfile, lang) == CLK_STDC11
 506            || CPP_OPTION (pfile, lang) == CLK_GNUC11)
 507     _cpp_define_builtin (pfile, "__STDC_VERSION__ 201112L");
 508   else if (CPP_OPTION (pfile, c99))
 509     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 510
 511   if (CPP_OPTION (pfile, uliterals)
 512       && !CPP_OPTION (pfile, cplusplus))
 513     {
 514       _cpp_define_builtin (pfile, "__STDC_UTF_16__ 1");
 515       _cpp_define_builtin (pfile, "__STDC_UTF_32__ 1");
 516     }
 517
 518   if (hosted)
 519     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 520   else
 521     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 522
 523   if (CPP_OPTION (pfile, objc))
 524     _cpp_define_builtin (pfile, "__OBJC__ 1");
 525 }
 526
 527 /* Sanity-checks are dependent on command-line options, so it is
 528    called as a subroutine of cpp_read_main_file ().  */
 529 #if ENABLE_CHECKING
 530 static void sanity_checks (cpp_reader *);
 531 static void sanity_checks (cpp_reader *pfile)
 532 {
 533   cppchar_t test = 0;
 534   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 535
 536   /* Sanity checks for assumptions about CPP arithmetic and target
 537      type precisions made by cpplib.  */
 538   test--;
 539   if (test < 1)
 540     cpp_error (pfile, CPP_DL_ICE, "cppchar_t must be an unsigned type");
 541
 542   if (CPP_OPTION (pfile, precision) > max_precision)
 543     cpp_error (pfile, CPP_DL_ICE,
 544                "preprocessor arithmetic has maximum precision of %lu bits;"
 545                " target requires %lu bits",
 546                (unsigned long) max_precision,
 547                (unsigned long) CPP_OPTION (pfile, precision));
 548
 549   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 550     cpp_error (pfile, CPP_DL_ICE,
 551                "CPP arithmetic must be at least as precise as a target int");
 552
 553   if (CPP_OPTION (pfile, char_precision) < 8)
 554     cpp_error (pfile, CPP_DL_ICE, "target char is less than 8 bits wide");
 555
 556   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 557     cpp_error (pfile, CPP_DL_ICE,
 558                "target wchar_t is narrower than target char");
 559
 560   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 561     cpp_error (pfile, CPP_DL_ICE,
 562                "target int is narrower than target char");
 563
 564   /* This is assumed in eval_token() and could be fixed if necessary.  */
 565   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 566     cpp_error (pfile, CPP_DL_ICE,
 567                "CPP half-integer narrower than CPP character");
 568
 569   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 570     cpp_error (pfile, CPP_DL_ICE,
 571                "CPP on this host cannot handle wide character constants over"
 572                " %lu bits, but the target requires %lu bits",
 573                (unsigned long) BITS_PER_CPPCHAR_T,
 574                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 575 }
 576 #else
 577 # define sanity_checks(PFILE)
 578 #endif
 579
 580 /* This is called after options have been parsed, and partially
 581    processed.  */
 582 void
 583 cpp_post_options (cpp_reader *pfile)
 584 {
 585   int flags;
 586
 587   sanity_checks (pfile);
 588
 589   post_options (pfile);
 590
 591   /* Mark named operators before handling command line macros.  */
 592   flags = 0;
 593   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 594     flags |= NODE_OPERATOR;
 595   if (CPP_OPTION (pfile, warn_cxx_operator_names))
 596     flags |= NODE_DIAGNOSTIC | NODE_WARN_OPERATOR;
 597   if (flags != 0)
 598     mark_named_operators (pfile, flags);
 599 }
 600
 601 /* Setup for processing input from the file named FNAME, or stdin if
 602    it is the empty string.  Return the original filename
 603    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 604 const char *
 605 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 606 {
 607   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 608     {
 609       if (!pfile->deps)
 610         pfile->deps = deps_init ();
 611
 612       /* Set the default target (if there is none already).  */
 613       deps_add_default_target (pfile->deps, fname);
 614     }
 615
 616   pfile->main_file
 617     = _cpp_find_file (pfile, fname, &pfile->no_search_path, false, 0, false);
 618   if (_cpp_find_failed (pfile->main_file))
 619     return NULL;
 620
 621   _cpp_stack_file (pfile, pfile->main_file, false);
 622
 623   /* For foo.i, read the original filename foo.c now, for the benefit
 624      of the front ends.  */
 625   if (CPP_OPTION (pfile, preprocessed))
 626     {
 627       read_original_filename (pfile);
 628       fname =
 629         ORDINARY_MAP_FILE_NAME
 630         ((LINEMAPS_LAST_ORDINARY_MAP (pfile->line_table)));
 631     }
 632   return fname;
 633 }
 634
 635 /* For preprocessed files, if the first tokens are of the form # NUM.
 636    handle the directive so we know the original file name.  This will
 637    generate file_change callbacks, which the front ends must handle
 638    appropriately given their state of initialization.  */
 639 static void
 640 read_original_filename (cpp_reader *pfile)
 641 {
 642   const cpp_token *token, *token1;
 643
 644   /* Lex ahead; if the first tokens are of the form # NUM, then
 645      process the directive, otherwise back up.  */
 646   token = _cpp_lex_direct (pfile);
 647   if (token->type == CPP_HASH)
 648     {
 649       pfile->state.in_directive = 1;
 650       token1 = _cpp_lex_direct (pfile);
 651       _cpp_backup_tokens (pfile, 1);
 652       pfile->state.in_directive = 0;
 653
 654       /* If it's a #line directive, handle it.  */
 655       if (token1->type == CPP_NUMBER
 656           && _cpp_handle_directive (pfile, token->flags & PREV_WHITE))
 657         {
 658           read_original_directory (pfile);
 659           return;
 660         }
 661     }
 662
 663   /* Backup as if nothing happened.  */
 664   _cpp_backup_tokens (pfile, 1);
 665 }
 666
 667 /* For preprocessed files, if the tokens following the first filename
 668    line is of the form # <line> "/path/name//", handle the
 669    directive so we know the original current directory.  */
 670 static void
 671 read_original_directory (cpp_reader *pfile)
 672 {
 673   const cpp_token *hash, *token;
 674
 675   /* Lex ahead; if the first tokens are of the form # NUM, then
 676      process the directive, otherwise back up.  */
 677   hash = _cpp_lex_direct (pfile);
 678   if (hash->type != CPP_HASH)
 679     {
 680       _cpp_backup_tokens (pfile, 1);
 681       return;
 682     }
 683
 684   token = _cpp_lex_direct (pfile);
 685
 686   if (token->type != CPP_NUMBER)
 687     {
 688       _cpp_backup_tokens (pfile, 2);
 689       return;
 690     }
 691
 692   token = _cpp_lex_direct (pfile);
 693
 694   if (token->type != CPP_STRING
 695       || ! (token->val.str.len >= 5
 696             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-2])
 697             && IS_DIR_SEPARATOR (token->val.str.text[token->val.str.len-3])))
 698     {
 699       _cpp_backup_tokens (pfile, 3);
 700       return;
 701     }
 702
 703   if (pfile->cb.dir_change)
 704     {
 705       char *debugdir = (char *) alloca (token->val.str.len - 3);
 706
 707       memcpy (debugdir, (const char *) token->val.str.text + 1,
 708               token->val.str.len - 4);
 709       debugdir[token->val.str.len - 4] = '\0';
 710
 711       pfile->cb.dir_change (pfile, debugdir);
 712     }
 713 }
 714
 715 /* This is called at the end of preprocessing.  It pops the last
 716    buffer and writes dependency output.
 717
 718    Maybe it should also reset state, such that you could call
 719    cpp_start_read with a new filename to restart processing.  */
 720 void
 721 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 722 {
 723   /* Warn about unused macros before popping the final buffer.  */
 724   if (CPP_OPTION (pfile, warn_unused_macros))
 725     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 726
 727   /* lex.c leaves the final buffer on the stack.  This it so that
 728      it returns an unending stream of CPP_EOFs to the client.  If we
 729      popped the buffer, we'd dereference a NULL buffer pointer and
 730      segfault.  It's nice to allow the client to do worry-free excess
 731      cpp_get_token calls.  */
 732   while (pfile->buffer)
 733     _cpp_pop_buffer (pfile);
 734
 735   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 736       && deps_stream)
 737     {
 738       deps_write (pfile->deps, deps_stream, 72);
 739
 740       if (CPP_OPTION (pfile, deps.phony_targets))
 741         deps_phony_targets (pfile->deps, deps_stream);
 742     }
 743
 744   /* Report on headers that could use multiple include guards.  */
 745   if (CPP_OPTION (pfile, print_include_names))
 746     _cpp_report_missing_guards (pfile);
 747 }
 748
 749 static void
 750 post_options (cpp_reader *pfile)
 751 {
 752   /* -Wtraditional is not useful in C++ mode.  */
 753   if (CPP_OPTION (pfile, cplusplus))
 754     CPP_OPTION (pfile, cpp_warn_traditional) = 0;
 755
 756   /* Permanently disable macro expansion if we are rescanning
 757      preprocessed text.  Read preprocesed source in ISO mode.  */
 758   if (CPP_OPTION (pfile, preprocessed))
 759     {
 760       if (!CPP_OPTION (pfile, directives_only))
 761         pfile->state.prevent_expansion = 1;
 762       CPP_OPTION (pfile, traditional) = 0;
 763     }
 764
 765   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 766     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 767
 768   if (CPP_OPTION (pfile, traditional))
 769     {
 770       CPP_OPTION (pfile, cplusplus_comments) = 0;
 771
 772       CPP_OPTION (pfile, trigraphs) = 0;
 773       CPP_OPTION (pfile, warn_trigraphs) = 0;
 774     }
 775 }