gcc/cppinit.c

   1 /* CPP Library.
   2    Copyright (C) 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
   4    Contributed by Per Bothner, 1994-95.
   5    Based on CCCP program by Paul Rubin, June 1986
   6    Adapted to ANSI C, Richard Stallman, Jan 1987
   7
   8 This program is free software; you can redistribute it and/or modify it
   9 under the terms of the GNU General Public License as published by the
  10 Free Software Foundation; either version 2, or (at your option) any
  11 later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "cpplib.h"
  27 #include "cpphash.h"
  28 #include "mkdeps.h"
  29
  30 static void init_library (void);
  31 static void mark_named_operators (cpp_reader *);
  32 static void read_original_filename (cpp_reader *);
  33 static void post_options (cpp_reader *);
  34
  35 /* If we have designated initializers (GCC >2.7) these tables can be
  36    initialized, constant data.  Otherwise, they have to be filled in at
  37    runtime.  */
  38 #if HAVE_DESIGNATED_INITIALIZERS
  39
  40 #define init_trigraph_map()  /* Nothing.  */
  41 #define TRIGRAPH_MAP \
  42 __extension__ const uchar _cpp_trigraph_map[UCHAR_MAX + 1] = {
  43
  44 #define END };
  45 #define s(p, v) [p] = v,
  46
  47 #else
  48
  49 #define TRIGRAPH_MAP uchar _cpp_trigraph_map[UCHAR_MAX + 1] = { 0 }; \
  50  static void init_trigraph_map (void) { \
  51  unsigned char *x = _cpp_trigraph_map;
  52
  53 #define END }
  54 #define s(p, v) x[p] = v;
  55
  56 #endif
  57
  58 TRIGRAPH_MAP
  59   s('=', '#')   s(')', ']')     s('!', '|')
  60   s('(', '[')   s('\'', '^')    s('>', '}')
  61   s('/', '\\')  s('<', '{')     s('-', '~')
  62 END
  63
  64 #undef s
  65 #undef END
  66 #undef TRIGRAPH_MAP
  67
  68 /* A set of booleans indicating what CPP features each source language
  69    requires.  */
  70 struct lang_flags
  71 {
  72   char c99;
  73   char cplusplus;
  74   char extended_numbers;
  75   char std;
  76   char cplusplus_comments;
  77   char digraphs;
  78 };
  79
  80 static const struct lang_flags lang_defaults[] =
  81 { /*              c99 c++ xnum std  //   digr  */
  82   /* GNUC89 */  { 0,  0,  1,   0,   1,   1     },
  83   /* GNUC99 */  { 1,  0,  1,   0,   1,   1     },
  84   /* STDC89 */  { 0,  0,  0,   1,   0,   0     },
  85   /* STDC94 */  { 0,  0,  0,   1,   0,   1     },
  86   /* STDC99 */  { 1,  0,  1,   1,   1,   1     },
  87   /* GNUCXX */  { 0,  1,  1,   0,   1,   1     },
  88   /* CXX98  */  { 0,  1,  1,   1,   1,   1     },
  89   /* ASM    */  { 0,  0,  1,   0,   1,   0     }
  90 };
  91
  92 /* Sets internal flags correctly for a given language.  */
  93 void
  94 cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
  95 {
  96   const struct lang_flags *l = &lang_defaults[(int) lang];
  97
  98   CPP_OPTION (pfile, lang) = lang;
  99
 100   CPP_OPTION (pfile, c99)                = l->c99;
 101   CPP_OPTION (pfile, cplusplus)          = l->cplusplus;
 102   CPP_OPTION (pfile, extended_numbers)   = l->extended_numbers;
 103   CPP_OPTION (pfile, std)                = l->std;
 104   CPP_OPTION (pfile, trigraphs)          = l->std;
 105   CPP_OPTION (pfile, cplusplus_comments) = l->cplusplus_comments;
 106   CPP_OPTION (pfile, digraphs)           = l->digraphs;
 107 }
 108
 109 /* Initialize library global state.  */
 110 static void
 111 init_library (void)
 112 {
 113   static int initialized = 0;
 114
 115   if (! initialized)
 116     {
 117       initialized = 1;
 118
 119       /* Set up the trigraph map.  This doesn't need to do anything if
 120          we were compiled with a compiler that supports C99 designated
 121          initializers.  */
 122       init_trigraph_map ();
 123     }
 124 }
 125
 126 /* Initialize a cpp_reader structure.  */
 127 cpp_reader *
 128 cpp_create_reader (enum c_lang lang, hash_table *table)
 129 {
 130   cpp_reader *pfile;
 131
 132   /* Initialize this instance of the library if it hasn't been already.  */
 133   init_library ();
 134
 135   pfile = (cpp_reader *) xcalloc (1, sizeof (cpp_reader));
 136
 137   cpp_set_lang (pfile, lang);
 138   CPP_OPTION (pfile, warn_import) = 1;
 139   CPP_OPTION (pfile, warn_multichar) = 1;
 140   CPP_OPTION (pfile, discard_comments) = 1;
 141   CPP_OPTION (pfile, discard_comments_in_macro_exp) = 1;
 142   CPP_OPTION (pfile, show_column) = 1;
 143   CPP_OPTION (pfile, tabstop) = 8;
 144   CPP_OPTION (pfile, operator_names) = 1;
 145   CPP_OPTION (pfile, warn_trigraphs) = 2;
 146   CPP_OPTION (pfile, warn_endif_labels) = 1;
 147   CPP_OPTION (pfile, warn_deprecated) = 1;
 148   CPP_OPTION (pfile, warn_long_long) = !CPP_OPTION (pfile, c99);
 149   CPP_OPTION (pfile, dollars_in_ident) = 1;
 150   CPP_OPTION (pfile, warn_dollars) = 1;
 151
 152   /* Default CPP arithmetic to something sensible for the host for the
 153      benefit of dumb users like fix-header.  */
 154   CPP_OPTION (pfile, precision) = CHAR_BIT * sizeof (long);
 155   CPP_OPTION (pfile, char_precision) = CHAR_BIT;
 156   CPP_OPTION (pfile, wchar_precision) = CHAR_BIT * sizeof (int);
 157   CPP_OPTION (pfile, int_precision) = CHAR_BIT * sizeof (int);
 158   CPP_OPTION (pfile, unsigned_char) = 0;
 159   CPP_OPTION (pfile, unsigned_wchar) = 1;
 160   CPP_OPTION (pfile, bytes_big_endian) = 1;  /* does not matter */
 161
 162   /* Default to no charset conversion.  */
 163   CPP_OPTION (pfile, narrow_charset) = 0;
 164   CPP_OPTION (pfile, wide_charset) = 0;
 165
 166   /* Initialize the line map.  Start at logical line 1, so we can use
 167      a line number of zero for special states.  */
 168   init_line_maps (&pfile->line_maps);
 169
 170   /* Initialize lexer state.  */
 171   pfile->state.save_comments = ! CPP_OPTION (pfile, discard_comments);
 172
 173   /* Set up static tokens.  */
 174   pfile->avoid_paste.type = CPP_PADDING;
 175   pfile->avoid_paste.val.source = NULL;
 176   pfile->eof.type = CPP_EOF;
 177   pfile->eof.flags = 0;
 178
 179   /* Create a token buffer for the lexer.  */
 180   _cpp_init_tokenrun (&pfile->base_run, 250);
 181   pfile->cur_run = &pfile->base_run;
 182   pfile->cur_token = pfile->base_run.base;
 183
 184   /* Initialize the base context.  */
 185   pfile->context = &pfile->base_context;
 186   pfile->base_context.macro = 0;
 187   pfile->base_context.prev = pfile->base_context.next = 0;
 188
 189   /* Aligned and unaligned storage.  */
 190   pfile->a_buff = _cpp_get_buff (pfile, 0);
 191   pfile->u_buff = _cpp_get_buff (pfile, 0);
 192
 193   /* The expression parser stack.  */
 194   _cpp_expand_op_stack (pfile);
 195
 196   /* Initialize the buffer obstack.  */
 197   gcc_obstack_init (&pfile->buffer_ob);
 198
 199   _cpp_init_includes (pfile);
 200
 201   _cpp_init_hashtable (pfile, table);
 202
 203   return pfile;
 204 }
 205
 206 /* Free resources used by PFILE.  Accessing PFILE after this function
 207    returns leads to undefined behavior.  Returns the error count.  */
 208 void
 209 cpp_destroy (cpp_reader *pfile)
 210 {
 211   cpp_context *context, *contextn;
 212   tokenrun *run, *runn;
 213
 214   free (pfile->op_stack);
 215
 216   while (CPP_BUFFER (pfile) != NULL)
 217     _cpp_pop_buffer (pfile);
 218
 219   if (pfile->out.base)
 220     free (pfile->out.base);
 221
 222   if (pfile->macro_buffer)
 223     {
 224       free (pfile->macro_buffer);
 225       pfile->macro_buffer = NULL;
 226       pfile->macro_buffer_len = 0;
 227     }
 228
 229   if (pfile->deps)
 230     deps_free (pfile->deps);
 231   obstack_free (&pfile->buffer_ob, 0);
 232
 233   _cpp_destroy_hashtable (pfile);
 234   _cpp_cleanup_includes (pfile);
 235   _cpp_destroy_iconv (pfile);
 236
 237   _cpp_free_buff (pfile->a_buff);
 238   _cpp_free_buff (pfile->u_buff);
 239   _cpp_free_buff (pfile->free_buffs);
 240
 241   for (run = &pfile->base_run; run; run = runn)
 242     {
 243       runn = run->next;
 244       free (run->base);
 245       if (run != &pfile->base_run)
 246         free (run);
 247     }
 248
 249   for (context = pfile->base_context.next; context; context = contextn)
 250     {
 251       contextn = context->next;
 252       free (context);
 253     }
 254
 255   free_line_maps (&pfile->line_maps);
 256   free (pfile);
 257 }
 258
 259 /* This structure defines one built-in identifier.  A node will be
 260    entered in the hash table under the name NAME, with value VALUE.
 261
 262    There are two tables of these.  builtin_array holds all the
 263    "builtin" macros: these are handled by builtin_macro() in
 264    cppmacro.c.  Builtin is somewhat of a misnomer -- the property of
 265    interest is that these macros require special code to compute their
 266    expansions.  The value is a "builtin_type" enumerator.
 267
 268    operator_array holds the C++ named operators.  These are keywords
 269    which act as aliases for punctuators.  In C++, they cannot be
 270    altered through #define, and #if recognizes them as operators.  In
 271    C, these are not entered into the hash table at all (but see
 272    <iso646.h>).  The value is a token-type enumerator.  */
 273 struct builtin
 274 {
 275   const uchar *name;
 276   unsigned short len;
 277   unsigned short value;
 278 };
 279
 280 #define B(n, t)    { DSC(n), t }
 281 static const struct builtin builtin_array[] =
 282 {
 283   B("__TIME__",          BT_TIME),
 284   B("__DATE__",          BT_DATE),
 285   B("__FILE__",          BT_FILE),
 286   B("__BASE_FILE__",     BT_BASE_FILE),
 287   B("__LINE__",          BT_SPECLINE),
 288   B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL),
 289   /* Keep builtins not used for -traditional-cpp at the end, and
 290      update init_builtins() if any more are added.  */
 291   B("_Pragma",           BT_PRAGMA),
 292   B("__STDC__",          BT_STDC),
 293 };
 294
 295 static const struct builtin operator_array[] =
 296 {
 297   B("and",      CPP_AND_AND),
 298   B("and_eq",   CPP_AND_EQ),
 299   B("bitand",   CPP_AND),
 300   B("bitor",    CPP_OR),
 301   B("compl",    CPP_COMPL),
 302   B("not",      CPP_NOT),
 303   B("not_eq",   CPP_NOT_EQ),
 304   B("or",       CPP_OR_OR),
 305   B("or_eq",    CPP_OR_EQ),
 306   B("xor",      CPP_XOR),
 307   B("xor_eq",   CPP_XOR_EQ)
 308 };
 309 #undef B
 310
 311 /* Mark the C++ named operators in the hash table.  */
 312 static void
 313 mark_named_operators (cpp_reader *pfile)
 314 {
 315   const struct builtin *b;
 316
 317   for (b = operator_array;
 318        b < (operator_array + ARRAY_SIZE (operator_array));
 319        b++)
 320     {
 321       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 322       hp->flags |= NODE_OPERATOR;
 323       hp->is_directive = 0;
 324       hp->directive_index = b->value;
 325     }
 326 }
 327
 328 /* Read the builtins table above and enter them, and language-specific
 329    macros, into the hash table.  HOSTED is true if this is a hosted
 330    environment.  */
 331 void
 332 cpp_init_builtins (cpp_reader *pfile, int hosted)
 333 {
 334   const struct builtin *b;
 335   size_t n = ARRAY_SIZE (builtin_array);
 336
 337   if (CPP_OPTION (pfile, traditional))
 338     n -= 2;
 339
 340   for(b = builtin_array; b < builtin_array + n; b++)
 341     {
 342       cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
 343       hp->type = NT_MACRO;
 344       hp->flags |= NODE_BUILTIN | NODE_WARN;
 345       hp->value.builtin = b->value;
 346     }
 347
 348   if (CPP_OPTION (pfile, cplusplus))
 349     _cpp_define_builtin (pfile, "__cplusplus 1");
 350   else if (CPP_OPTION (pfile, lang) == CLK_ASM)
 351     _cpp_define_builtin (pfile, "__ASSEMBLER__ 1");
 352   else if (CPP_OPTION (pfile, lang) == CLK_STDC94)
 353     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199409L");
 354   else if (CPP_OPTION (pfile, c99))
 355     _cpp_define_builtin (pfile, "__STDC_VERSION__ 199901L");
 356
 357   if (hosted)
 358     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 1");
 359   else
 360     _cpp_define_builtin (pfile, "__STDC_HOSTED__ 0");
 361
 362   if (CPP_OPTION (pfile, objc))
 363     _cpp_define_builtin (pfile, "__OBJC__ 1");
 364 }
 365
 366 /* Sanity-checks are dependent on command-line options, so it is
 367    called as a subroutine of cpp_read_main_file ().  */
 368 #if ENABLE_CHECKING
 369 static void sanity_checks (cpp_reader *);
 370 static void sanity_checks (cpp_reader *pfile)
 371 {
 372   cppchar_t test = 0;
 373   size_t max_precision = 2 * CHAR_BIT * sizeof (cpp_num_part);
 374
 375   /* Sanity checks for assumptions about CPP arithmetic and target
 376      type precisions made by cpplib.  */
 377   test--;
 378   if (test < 1)
 379     cpp_error (pfile, DL_ICE, "cppchar_t must be an unsigned type");
 380
 381   if (CPP_OPTION (pfile, precision) > max_precision)
 382     cpp_error (pfile, DL_ICE,
 383                "preprocessor arithmetic has maximum precision of %lu bits;"
 384                " target requires %lu bits",
 385                (unsigned long) max_precision,
 386                (unsigned long) CPP_OPTION (pfile, precision));
 387
 388   if (CPP_OPTION (pfile, precision) < CPP_OPTION (pfile, int_precision))
 389     cpp_error (pfile, DL_ICE,
 390                "CPP arithmetic must be at least as precise as a target int");
 391
 392   if (CPP_OPTION (pfile, char_precision) < 8)
 393     cpp_error (pfile, DL_ICE, "target char is less than 8 bits wide");
 394
 395   if (CPP_OPTION (pfile, wchar_precision) < CPP_OPTION (pfile, char_precision))
 396     cpp_error (pfile, DL_ICE,
 397                "target wchar_t is narrower than target char");
 398
 399   if (CPP_OPTION (pfile, int_precision) < CPP_OPTION (pfile, char_precision))
 400     cpp_error (pfile, DL_ICE,
 401                "target int is narrower than target char");
 402
 403   /* This is assumed in eval_token() and could be fixed if necessary.  */
 404   if (sizeof (cppchar_t) > sizeof (cpp_num_part))
 405     cpp_error (pfile, DL_ICE, "CPP half-integer narrower than CPP character");
 406
 407   if (CPP_OPTION (pfile, wchar_precision) > BITS_PER_CPPCHAR_T)
 408     cpp_error (pfile, DL_ICE,
 409                "CPP on this host cannot handle wide character constants over"
 410                " %lu bits, but the target requires %lu bits",
 411                (unsigned long) BITS_PER_CPPCHAR_T,
 412                (unsigned long) CPP_OPTION (pfile, wchar_precision));
 413 }
 414 #else
 415 # define sanity_checks(PFILE)
 416 #endif
 417
 418 /* Add a dependency target.  Can be called any number of times before
 419    cpp_read_main_file().  If no targets have been added before
 420    cpp_read_main_file(), then the default target is used.  */
 421 void
 422 cpp_add_dependency_target (cpp_reader *pfile, const char *target, int quote)
 423 {
 424   if (!pfile->deps)
 425     pfile->deps = deps_init ();
 426
 427   deps_add_target (pfile->deps, target, quote);
 428 }
 429
 430 /* This is called after options have been parsed, and partially
 431    processed.  Setup for processing input from the file named FNAME,
 432    or stdin if it is the empty string.  Return the original filename
 433    on success (e.g. foo.i->foo.c), or NULL on failure.  */
 434 const char *
 435 cpp_read_main_file (cpp_reader *pfile, const char *fname)
 436 {
 437   sanity_checks (pfile);
 438
 439   post_options (pfile);
 440
 441   /* Mark named operators before handling command line macros.  */
 442   if (CPP_OPTION (pfile, cplusplus) && CPP_OPTION (pfile, operator_names))
 443     mark_named_operators (pfile);
 444
 445   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE)
 446     {
 447       if (!pfile->deps)
 448         pfile->deps = deps_init ();
 449
 450       /* Set the default target (if there is none already).  */
 451       deps_add_default_target (pfile->deps, fname);
 452     }
 453
 454   /* Open the main input file.  */
 455   pfile->line = 1;
 456   if (!_cpp_read_file (pfile, fname))
 457     return NULL;
 458
 459   /* Set this here so the client can change the option if it wishes,
 460      and after stacking the main file so we don't trace the main
 461      file.  */
 462   pfile->line_maps.trace_includes = CPP_OPTION (pfile, print_include_names);
 463
 464   /* For foo.i, read the original filename foo.c now, for the benefit
 465      of the front ends.  */
 466   if (CPP_OPTION (pfile, preprocessed))
 467     read_original_filename (pfile);
 468
 469   return pfile->map->to_file;
 470 }
 471
 472 /* For preprocessed files, if the first tokens are of the form # NUM.
 473    handle the directive so we know the original file name.  This will
 474    generate file_change callbacks, which the front ends must handle
 475    appropriately given their state of initialization.  */
 476 static void
 477 read_original_filename (cpp_reader *pfile)
 478 {
 479   const cpp_token *token, *token1;
 480
 481   /* Lex ahead; if the first tokens are of the form # NUM, then
 482      process the directive, otherwise back up.  */
 483   token = _cpp_lex_direct (pfile);
 484   if (token->type == CPP_HASH)
 485     {
 486       token1 = _cpp_lex_direct (pfile);
 487       _cpp_backup_tokens (pfile, 1);
 488
 489       /* If it's a #line directive, handle it.  */
 490       if (token1->type == CPP_NUMBER)
 491         {
 492           _cpp_handle_directive (pfile, token->flags & PREV_WHITE);
 493           return;
 494         }
 495     }
 496
 497   /* Backup as if nothing happened.  */
 498   _cpp_backup_tokens (pfile, 1);
 499 }
 500
 501 /* This is called at the end of preprocessing.  It pops the last
 502    buffer and writes dependency output, and returns the number of
 503    errors.
 504
 505    Maybe it should also reset state, such that you could call
 506    cpp_start_read with a new filename to restart processing.  */
 507 int
 508 cpp_finish (cpp_reader *pfile, FILE *deps_stream)
 509 {
 510   /* Warn about unused macros before popping the final buffer.  */
 511   if (CPP_OPTION (pfile, warn_unused_macros))
 512     cpp_forall_identifiers (pfile, _cpp_warn_if_unused_macro, NULL);
 513
 514   /* cpplex.c leaves the final buffer on the stack.  This it so that
 515      it returns an unending stream of CPP_EOFs to the client.  If we
 516      popped the buffer, we'd dereference a NULL buffer pointer and
 517      segfault.  It's nice to allow the client to do worry-free excess
 518      cpp_get_token calls.  */
 519   while (pfile->buffer)
 520     _cpp_pop_buffer (pfile);
 521
 522   /* Don't write the deps file if there are errors.  */
 523   if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
 524       && deps_stream && pfile->errors == 0)
 525     {
 526       deps_write (pfile->deps, deps_stream, 72);
 527
 528       if (CPP_OPTION (pfile, deps.phony_targets))
 529         deps_phony_targets (pfile->deps, deps_stream);
 530     }
 531
 532   /* Report on headers that could use multiple include guards.  */
 533   if (CPP_OPTION (pfile, print_include_names))
 534     _cpp_report_missing_guards (pfile);
 535
 536   return pfile->errors;
 537 }
 538
 539 static void
 540 post_options (cpp_reader *pfile)
 541 {
 542   /* -Wtraditional is not useful in C++ mode.  */
 543   if (CPP_OPTION (pfile, cplusplus))
 544     CPP_OPTION (pfile, warn_traditional) = 0;
 545
 546   /* Permanently disable macro expansion if we are rescanning
 547      preprocessed text.  Read preprocesed source in ISO mode.  */
 548   if (CPP_OPTION (pfile, preprocessed))
 549     {
 550       pfile->state.prevent_expansion = 1;
 551       CPP_OPTION (pfile, traditional) = 0;
 552     }
 553
 554   if (CPP_OPTION (pfile, warn_trigraphs) == 2)
 555     CPP_OPTION (pfile, warn_trigraphs) = !CPP_OPTION (pfile, trigraphs);
 556
 557   if (CPP_OPTION (pfile, traditional))
 558     {
 559       /* Traditional CPP does not accurately track column information.  */
 560       CPP_OPTION (pfile, show_column) = 0;
 561       CPP_OPTION (pfile, trigraphs) = 0;
 562       CPP_OPTION (pfile, warn_trigraphs) = 0;
 563     }
 564 }