gcc/c-family/c-ppoutput.c

   1 /* Preprocess only, using cpplib.
   2    Copyright (C) 1995-2014 Free Software Foundation, Inc.
   3    Written by Per Bothner, 1994-95.
   4
   5    This program is free software; you can redistribute it and/or modify it
   6    under the terms of the GNU General Public License as published by the
   7    Free Software Foundation; either version 3, or (at your option) any
   8    later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; see the file COPYING3.  If not see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include "config.h"
  20 #include "system.h"
  21 #include "coretypes.h"
  22 #include "cpplib.h"
  23 #include "../libcpp/internal.h"
  24 #include "tree.h"
  25 #include "c-common.h"           /* For flags.  */
  26 #include "c-pragma.h"           /* For parse_in.  */
  27
  28 /* Encapsulates state used to convert a stream of tokens into a text
  29    file.  */
  30 static struct
  31 {
  32   FILE *outf;                   /* Stream to write to.  */
  33   const cpp_token *prev;        /* Previous token.  */
  34   const cpp_token *source;      /* Source token for spacing.  */
  35   int src_line;                 /* Line number currently being written.  */
  36   unsigned char printed;        /* Nonzero if something output at line.  */
  37   bool first_time;              /* pp_file_change hasn't been called yet.  */
  38   const char *src_file;         /* Current source file.  */
  39   bool prev_was_system_token;   /* True if the previous token was a
  40                                    system token.*/
  41 } print;
  42
  43 /* Defined and undefined macros being queued for output with -dU at
  44    the next newline.  */
  45 typedef struct macro_queue
  46 {
  47   struct macro_queue *next;     /* Next macro in the list.  */
  48   char *macro;                  /* The name of the macro if not
  49                                    defined, the full definition if
  50                                    defined.  */
  51 } macro_queue;
  52 static macro_queue *define_queue, *undef_queue;
  53
  54 /* General output routines.  */
  55 static void scan_translation_unit (cpp_reader *);
  56 static void print_lines_directives_only (int, const void *, size_t);
  57 static void scan_translation_unit_directives_only (cpp_reader *);
  58 static void scan_translation_unit_trad (cpp_reader *);
  59 static void account_for_newlines (const unsigned char *, size_t);
  60 static int dump_macro (cpp_reader *, cpp_hashnode *, void *);
  61 static void dump_queued_macros (cpp_reader *);
  62
  63 static bool print_line_1 (source_location, const char*, FILE *);
  64 static bool print_line (source_location, const char *);
  65 static bool maybe_print_line_1 (source_location, FILE *);
  66 static bool maybe_print_line (source_location);
  67 static bool do_line_change (cpp_reader *, const cpp_token *,
  68                             source_location, int);
  69
  70 /* Callback routines for the parser.   Most of these are active only
  71    in specific modes.  */
  72 static void cb_line_change (cpp_reader *, const cpp_token *, int);
  73 static void cb_define (cpp_reader *, source_location, cpp_hashnode *);
  74 static void cb_undef (cpp_reader *, source_location, cpp_hashnode *);
  75 static void cb_used_define (cpp_reader *, source_location, cpp_hashnode *);
  76 static void cb_used_undef (cpp_reader *, source_location, cpp_hashnode *);
  77 static void cb_include (cpp_reader *, source_location, const unsigned char *,
  78                         const char *, int, const cpp_token **);
  79 static void cb_ident (cpp_reader *, source_location, const cpp_string *);
  80 static void cb_def_pragma (cpp_reader *, source_location);
  81 static void cb_read_pch (cpp_reader *pfile, const char *name,
  82                          int fd, const char *orig_name);
  83
  84 /* Preprocess and output.  */
  85 void
  86 preprocess_file (cpp_reader *pfile)
  87 {
  88   /* A successful cpp_read_main_file guarantees that we can call
  89      cpp_scan_nooutput or cpp_get_token next.  */
  90   if (flag_no_output && pfile->buffer)
  91     {
  92       /* Scan -included buffers, then the main file.  */
  93       while (pfile->buffer->prev)
  94         cpp_scan_nooutput (pfile);
  95       cpp_scan_nooutput (pfile);
  96     }
  97   else if (cpp_get_options (pfile)->traditional)
  98     scan_translation_unit_trad (pfile);
  99   else if (cpp_get_options (pfile)->directives_only
 100            && !cpp_get_options (pfile)->preprocessed)
 101     scan_translation_unit_directives_only (pfile);
 102   else
 103     scan_translation_unit (pfile);
 104
 105   /* -dM command line option.  Should this be elsewhere?  */
 106   if (flag_dump_macros == 'M')
 107     cpp_forall_identifiers (pfile, dump_macro, NULL);
 108
 109   /* Flush any pending output.  */
 110   if (print.printed)
 111     putc ('\n', print.outf);
 112 }
 113
 114 /* Set up the callbacks as appropriate.  */
 115 void
 116 init_pp_output (FILE *out_stream)
 117 {
 118   cpp_callbacks *cb = cpp_get_callbacks (parse_in);
 119
 120   if (!flag_no_output)
 121     {
 122       cb->line_change = cb_line_change;
 123       /* Don't emit #pragma or #ident directives if we are processing
 124          assembly language; the assembler may choke on them.  */
 125       if (cpp_get_options (parse_in)->lang != CLK_ASM)
 126         {
 127           cb->ident      = cb_ident;
 128           cb->def_pragma = cb_def_pragma;
 129         }
 130     }
 131
 132   if (flag_dump_includes)
 133     cb->include  = cb_include;
 134
 135   if (flag_pch_preprocess)
 136     {
 137       cb->valid_pch = c_common_valid_pch;
 138       cb->read_pch = cb_read_pch;
 139     }
 140
 141   if (flag_dump_macros == 'N' || flag_dump_macros == 'D')
 142     {
 143       cb->define = cb_define;
 144       cb->undef  = cb_undef;
 145     }
 146
 147   if (flag_dump_macros == 'U')
 148     {
 149       cb->before_define = dump_queued_macros;
 150       cb->used_define = cb_used_define;
 151       cb->used_undef = cb_used_undef;
 152     }
 153
 154   cb->has_attribute = c_common_has_attribute;
 155
 156   /* Initialize the print structure.  */
 157   print.src_line = 1;
 158   print.printed = 0;
 159   print.prev = 0;
 160   print.outf = out_stream;
 161   print.first_time = 1;
 162   print.src_file = "";
 163   print.prev_was_system_token = false;
 164 }
 165
 166 /* Writes out the preprocessed file, handling spacing and paste
 167    avoidance issues.  */
 168 static void
 169 scan_translation_unit (cpp_reader *pfile)
 170 {
 171   bool avoid_paste = false;
 172   bool do_line_adjustments
 173     = cpp_get_options (parse_in)->lang != CLK_ASM
 174       && !flag_no_line_commands;
 175   bool in_pragma = false;
 176   bool line_marker_emitted = false;
 177
 178   print.source = NULL;
 179   for (;;)
 180     {
 181       source_location loc;
 182       const cpp_token *token = cpp_get_token_with_location (pfile, &loc);
 183
 184       if (token->type == CPP_PADDING)
 185         {
 186           avoid_paste = true;
 187           if (print.source == NULL
 188               || (!(print.source->flags & PREV_WHITE)
 189                   && token->val.source == NULL))
 190             print.source = token->val.source;
 191           continue;
 192         }
 193
 194       if (token->type == CPP_EOF)
 195         break;
 196
 197       /* Subtle logic to output a space if and only if necessary.  */
 198       if (avoid_paste)
 199         {
 200           int src_line = LOCATION_LINE (loc);
 201
 202           if (print.source == NULL)
 203             print.source = token;
 204
 205           if (src_line != print.src_line
 206               && do_line_adjustments
 207               && !in_pragma)
 208             {
 209               line_marker_emitted = do_line_change (pfile, token, loc, false);
 210               putc (' ', print.outf);
 211             }
 212           else if (print.source->flags & PREV_WHITE
 213                    || (print.prev
 214                        && cpp_avoid_paste (pfile, print.prev, token))
 215                    || (print.prev == NULL && token->type == CPP_HASH))
 216             putc (' ', print.outf);
 217         }
 218       else if (token->flags & PREV_WHITE)
 219         {
 220           int src_line = LOCATION_LINE (loc);
 221
 222           if (src_line != print.src_line
 223               && do_line_adjustments
 224               && !in_pragma)
 225             line_marker_emitted = do_line_change (pfile, token, loc, false);
 226           putc (' ', print.outf);
 227         }
 228
 229       avoid_paste = false;
 230       print.source = NULL;
 231       print.prev = token;
 232       if (token->type == CPP_PRAGMA)
 233         {
 234           const char *space;
 235           const char *name;
 236
 237           line_marker_emitted = maybe_print_line (token->src_loc);
 238           fputs ("#pragma ", print.outf);
 239           c_pp_lookup_pragma (token->val.pragma, &space, &name);
 240           if (space)
 241             fprintf (print.outf, "%s %s", space, name);
 242           else
 243             fprintf (print.outf, "%s", name);
 244           print.printed = 1;
 245           in_pragma = true;
 246         }
 247       else if (token->type == CPP_PRAGMA_EOL)
 248         {
 249           maybe_print_line (token->src_loc);
 250           in_pragma = false;
 251         }
 252       else
 253         {
 254           if (cpp_get_options (parse_in)->debug)
 255               linemap_dump_location (line_table, token->src_loc,
 256                                      print.outf);
 257
 258           if (do_line_adjustments
 259               && !in_pragma
 260               && !line_marker_emitted
 261               && print.prev_was_system_token != !!in_system_header_at(loc)
 262               && !is_location_from_builtin_token (loc))
 263             /* The system-ness of this token is different from the one
 264                of the previous token.  Let's emit a line change to
 265                mark the new system-ness before we emit the token.  */
 266             {
 267               do_line_change (pfile, token, loc, false);
 268               print.prev_was_system_token = !!in_system_header_at(loc);
 269             }
 270           cpp_output_token (token, print.outf);
 271           line_marker_emitted = false;
 272         }
 273
 274       /* CPP_COMMENT tokens and raw-string literal tokens can
 275          have embedded new-line characters.  Rather than enumerating
 276          all the possible token types just check if token uses
 277          val.str union member.  */
 278       if (cpp_token_val_index (token) == CPP_TOKEN_FLD_STR)
 279         account_for_newlines (token->val.str.text, token->val.str.len);
 280     }
 281 }
 282
 283 static void
 284 print_lines_directives_only (int lines, const void *buf, size_t size)
 285 {
 286   print.src_line += lines;
 287   fwrite (buf, 1, size, print.outf);
 288 }
 289
 290 /* Writes out the preprocessed file, handling spacing and paste
 291    avoidance issues.  */
 292 static void
 293 scan_translation_unit_directives_only (cpp_reader *pfile)
 294 {
 295   struct _cpp_dir_only_callbacks cb;
 296
 297   cb.print_lines = print_lines_directives_only;
 298   cb.maybe_print_line = (void (*) (source_location)) maybe_print_line;
 299
 300   _cpp_preprocess_dir_only (pfile, &cb);
 301 }
 302
 303 /* Adjust print.src_line for newlines embedded in output.  */
 304 static void
 305 account_for_newlines (const unsigned char *str, size_t len)
 306 {
 307   while (len--)
 308     if (*str++ == '\n')
 309       print.src_line++;
 310 }
 311
 312 /* Writes out a traditionally preprocessed file.  */
 313 static void
 314 scan_translation_unit_trad (cpp_reader *pfile)
 315 {
 316   while (_cpp_read_logical_line_trad (pfile))
 317     {
 318       size_t len = pfile->out.cur - pfile->out.base;
 319       maybe_print_line (pfile->out.first_line);
 320       fwrite (pfile->out.base, 1, len, print.outf);
 321       print.printed = 1;
 322       if (!CPP_OPTION (pfile, discard_comments))
 323         account_for_newlines (pfile->out.base, len);
 324     }
 325 }
 326
 327 /* If the token read on logical line LINE needs to be output on a
 328    different line to the current one, output the required newlines or
 329    a line marker.  If a line marker was emitted, return TRUE otherwise
 330    return FALSE.  */
 331
 332 static bool
 333 maybe_print_line_1 (source_location src_loc, FILE *stream)
 334 {
 335   bool emitted_line_marker = false;
 336   int src_line = LOCATION_LINE (src_loc);
 337   const char *src_file = LOCATION_FILE (src_loc);
 338
 339   /* End the previous line of text.  */
 340   if (print.printed)
 341     {
 342       putc ('\n', stream);
 343       print.src_line++;
 344       print.printed = 0;
 345     }
 346
 347   if (!flag_no_line_commands
 348       && src_line >= print.src_line
 349       && src_line < print.src_line + 8
 350       && strcmp (src_file, print.src_file) == 0)
 351     {
 352       while (src_line > print.src_line)
 353         {
 354           putc ('\n', stream);
 355           print.src_line++;
 356         }
 357     }
 358   else
 359     emitted_line_marker = print_line_1 (src_loc, "", stream);
 360
 361   return emitted_line_marker;
 362 }
 363
 364 /* If the token read on logical line LINE needs to be output on a
 365    different line to the current one, output the required newlines or
 366    a line marker.  If a line marker was emitted, return TRUE otherwise
 367    return FALSE.  */
 368
 369 static bool
 370 maybe_print_line (source_location src_loc)
 371 {
 372   if (cpp_get_options (parse_in)->debug)
 373     linemap_dump_location (line_table, src_loc,
 374                            print.outf);
 375   return maybe_print_line_1 (src_loc, print.outf);
 376 }
 377
 378 /* Output a line marker for logical line LINE.  Special flags are "1"
 379    or "2" indicating entering or leaving a file.  If the line marker
 380    was effectively emitted, return TRUE otherwise return FALSE.  */
 381
 382 static bool
 383 print_line_1 (source_location src_loc, const char *special_flags, FILE *stream)
 384 {
 385   bool emitted_line_marker = false;
 386
 387   /* End any previous line of text.  */
 388   if (print.printed)
 389     putc ('\n', stream);
 390   print.printed = 0;
 391
 392   if (!flag_no_line_commands)
 393     {
 394       const char *file_path = LOCATION_FILE (src_loc);
 395       int sysp;
 396       size_t to_file_len = strlen (file_path);
 397       unsigned char *to_file_quoted =
 398          (unsigned char *) alloca (to_file_len * 4 + 1);
 399       unsigned char *p;
 400
 401       print.src_line = LOCATION_LINE (src_loc);
 402       print.src_file = file_path;
 403
 404       /* cpp_quote_string does not nul-terminate, so we have to do it
 405          ourselves.  */
 406       p = cpp_quote_string (to_file_quoted,
 407                             (const unsigned char *) file_path,
 408                             to_file_len);
 409       *p = '\0';
 410       fprintf (stream, "# %u \"%s\"%s",
 411                print.src_line == 0 ? 1 : print.src_line,
 412                to_file_quoted, special_flags);
 413
 414       sysp = in_system_header_at (src_loc);
 415       if (sysp == 2)
 416         fputs (" 3 4", stream);
 417       else if (sysp == 1)
 418         fputs (" 3", stream);
 419
 420       putc ('\n', stream);
 421       emitted_line_marker = true;
 422     }
 423
 424   return emitted_line_marker;
 425 }
 426
 427 /* Output a line marker for logical line LINE.  Special flags are "1"
 428    or "2" indicating entering or leaving a file.  Return TRUE if a
 429    line marker was effectively emitted, FALSE otherwise.  */
 430
 431 static bool
 432 print_line (source_location src_loc, const char *special_flags)
 433 {
 434     if (cpp_get_options (parse_in)->debug)
 435       linemap_dump_location (line_table, src_loc,
 436                              print.outf);
 437     return print_line_1 (src_loc, special_flags, print.outf);
 438 }
 439
 440 /* Helper function for cb_line_change and scan_translation_unit.
 441    Return TRUE if a line marker is emitted, FALSE otherwise.  */
 442 static bool
 443 do_line_change (cpp_reader *pfile, const cpp_token *token,
 444                 source_location src_loc, int parsing_args)
 445 {
 446   bool emitted_line_marker = false;
 447   if (define_queue || undef_queue)
 448     dump_queued_macros (pfile);
 449
 450   if (token->type == CPP_EOF || parsing_args)
 451     return false;
 452
 453   emitted_line_marker = maybe_print_line (src_loc);
 454   print.prev = 0;
 455   print.source = 0;
 456
 457   /* Supply enough spaces to put this token in its original column,
 458      one space per column greater than 2, since scan_translation_unit
 459      will provide a space if PREV_WHITE.  Don't bother trying to
 460      reconstruct tabs; we can't get it right in general, and nothing
 461      ought to care.  Some things do care; the fault lies with them.  */
 462   if (!CPP_OPTION (pfile, traditional))
 463     {
 464       int spaces = LOCATION_COLUMN (src_loc) - 2;
 465       print.printed = 1;
 466
 467       while (-- spaces >= 0)
 468         putc (' ', print.outf);
 469     }
 470
 471   return emitted_line_marker;
 472 }
 473
 474 /* Called when a line of output is started.  TOKEN is the first token
 475    of the line, and at end of file will be CPP_EOF.  */
 476 static void
 477 cb_line_change (cpp_reader *pfile, const cpp_token *token,
 478                 int parsing_args)
 479 {
 480   do_line_change (pfile, token, token->src_loc, parsing_args);
 481 }
 482
 483 static void
 484 cb_ident (cpp_reader *pfile ATTRIBUTE_UNUSED, source_location line,
 485           const cpp_string *str)
 486 {
 487   maybe_print_line (line);
 488   fprintf (print.outf, "#ident %s\n", str->text);
 489   print.src_line++;
 490 }
 491
 492 static void
 493 cb_define (cpp_reader *pfile, source_location line, cpp_hashnode *node)
 494 {
 495   const struct line_map *map;
 496
 497   maybe_print_line (line);
 498   fputs ("#define ", print.outf);
 499
 500   /* 'D' is whole definition; 'N' is name only.  */
 501   if (flag_dump_macros == 'D')
 502     fputs ((const char *) cpp_macro_definition (pfile, node),
 503            print.outf);
 504   else
 505     fputs ((const char *) NODE_NAME (node), print.outf);
 506
 507   putc ('\n', print.outf);
 508   linemap_resolve_location (line_table, line,
 509                             LRK_MACRO_DEFINITION_LOCATION,
 510                             &map);
 511   if (LINEMAP_LINE (map) != 0)
 512     print.src_line++;
 513 }
 514
 515 static void
 516 cb_undef (cpp_reader *pfile ATTRIBUTE_UNUSED, source_location line,
 517           cpp_hashnode *node)
 518 {
 519   maybe_print_line (line);
 520   fprintf (print.outf, "#undef %s\n", NODE_NAME (node));
 521   print.src_line++;
 522 }
 523
 524 static void
 525 cb_used_define (cpp_reader *pfile, source_location line ATTRIBUTE_UNUSED,
 526                 cpp_hashnode *node)
 527 {
 528   macro_queue *q;
 529   if (node->flags & NODE_BUILTIN)
 530     return;
 531   q = XNEW (macro_queue);
 532   q->macro = xstrdup ((const char *) cpp_macro_definition (pfile, node));
 533   q->next = define_queue;
 534   define_queue = q;
 535 }
 536
 537 static void
 538 cb_used_undef (cpp_reader *pfile ATTRIBUTE_UNUSED,
 539                source_location line ATTRIBUTE_UNUSED,
 540                cpp_hashnode *node)
 541 {
 542   macro_queue *q;
 543   q = XNEW (macro_queue);
 544   q->macro = xstrdup ((const char *) NODE_NAME (node));
 545   q->next = undef_queue;
 546   undef_queue = q;
 547 }
 548
 549 static void
 550 dump_queued_macros (cpp_reader *pfile ATTRIBUTE_UNUSED)
 551 {
 552   macro_queue *q;
 553
 554   /* End the previous line of text.  */
 555   if (print.printed)
 556     {
 557       putc ('\n', print.outf);
 558       print.src_line++;
 559       print.printed = 0;
 560     }
 561
 562   for (q = define_queue; q;)
 563     {
 564       macro_queue *oq;
 565       fputs ("#define ", print.outf);
 566       fputs (q->macro, print.outf);
 567       putc ('\n', print.outf);
 568       print.src_line++;
 569       oq = q;
 570       q = q->next;
 571       free (oq->macro);
 572       free (oq);
 573     }
 574   define_queue = NULL;
 575   for (q = undef_queue; q;)
 576     {
 577       macro_queue *oq;
 578       fprintf (print.outf, "#undef %s\n", q->macro);
 579       print.src_line++;
 580       oq = q;
 581       q = q->next;
 582       free (oq->macro);
 583       free (oq);
 584     }
 585   undef_queue = NULL;
 586 }
 587
 588 static void
 589 cb_include (cpp_reader *pfile ATTRIBUTE_UNUSED, source_location line,
 590             const unsigned char *dir, const char *header, int angle_brackets,
 591             const cpp_token **comments)
 592 {
 593   maybe_print_line (line);
 594   if (angle_brackets)
 595     fprintf (print.outf, "#%s <%s>", dir, header);
 596   else
 597     fprintf (print.outf, "#%s \"%s\"", dir, header);
 598
 599   if (comments != NULL)
 600     {
 601       while (*comments != NULL)
 602         {
 603           if ((*comments)->flags & PREV_WHITE)
 604             putc (' ', print.outf);
 605           cpp_output_token (*comments, print.outf);
 606           ++comments;
 607         }
 608     }
 609
 610   putc ('\n', print.outf);
 611   print.src_line++;
 612 }
 613
 614 /* Callback called when -fworking-director and -E to emit working
 615    directory in cpp output file.  */
 616
 617 void
 618 pp_dir_change (cpp_reader *pfile ATTRIBUTE_UNUSED, const char *dir)
 619 {
 620   size_t to_file_len = strlen (dir);
 621   unsigned char *to_file_quoted =
 622      (unsigned char *) alloca (to_file_len * 4 + 1);
 623   unsigned char *p;
 624
 625   /* cpp_quote_string does not nul-terminate, so we have to do it ourselves.  */
 626   p = cpp_quote_string (to_file_quoted, (const unsigned char *) dir, to_file_len);
 627   *p = '\0';
 628   fprintf (print.outf, "# 1 \"%s//\"\n", to_file_quoted);
 629 }
 630
 631 /* The file name, line number or system header flags have changed, as
 632    described in MAP.  */
 633
 634 void
 635 pp_file_change (const struct line_map *map)
 636 {
 637   const char *flags = "";
 638
 639   if (flag_no_line_commands)
 640     return;
 641
 642   if (map != NULL)
 643     {
 644       input_location = map->start_location;
 645       if (print.first_time)
 646         {
 647           /* Avoid printing foo.i when the main file is foo.c.  */
 648           if (!cpp_get_options (parse_in)->preprocessed)
 649             print_line (map->start_location, flags);
 650           print.first_time = 0;
 651         }
 652       else
 653         {
 654           /* Bring current file to correct line when entering a new file.  */
 655           if (map->reason == LC_ENTER)
 656             {
 657               const struct line_map *from = INCLUDED_FROM (line_table, map);
 658               maybe_print_line (LAST_SOURCE_LINE_LOCATION (from));
 659             }
 660           if (map->reason == LC_ENTER)
 661             flags = " 1";
 662           else if (map->reason == LC_LEAVE)
 663             flags = " 2";
 664           print_line (map->start_location, flags);
 665         }
 666     }
 667 }
 668
 669 /* Copy a #pragma directive to the preprocessed output.  */
 670 static void
 671 cb_def_pragma (cpp_reader *pfile, source_location line)
 672 {
 673   maybe_print_line (line);
 674   fputs ("#pragma ", print.outf);
 675   cpp_output_line (pfile, print.outf);
 676   print.src_line++;
 677 }
 678
 679 /* Dump out the hash table.  */
 680 static int
 681 dump_macro (cpp_reader *pfile, cpp_hashnode *node, void *v ATTRIBUTE_UNUSED)
 682 {
 683   if (node->type == NT_MACRO && !(node->flags & NODE_BUILTIN))
 684     {
 685       fputs ("#define ", print.outf);
 686       fputs ((const char *) cpp_macro_definition (pfile, node),
 687              print.outf);
 688       putc ('\n', print.outf);
 689       print.src_line++;
 690     }
 691
 692   return 1;
 693 }
 694
 695 /* Load in the PCH file NAME, open on FD.  It was originally searched for
 696    by ORIG_NAME.  Also, print out a #include command so that the PCH
 697    file can be loaded when the preprocessed output is compiled.  */
 698
 699 static void
 700 cb_read_pch (cpp_reader *pfile, const char *name,
 701              int fd, const char *orig_name ATTRIBUTE_UNUSED)
 702 {
 703   c_common_read_pch (pfile, name, fd, orig_name);
 704
 705   fprintf (print.outf, "#pragma GCC pch_preprocess \"%s\"\n", name);
 706   print.src_line++;
 707 }