files.c 56.6 KB
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/* Part of CPP library.  File handling.
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   Copyright (C) 1986-2018 Free Software Foundation, Inc.
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   Written by Per Bothner, 1994.
   Based on CCCP program by Paul Rubin, June 1986
   Adapted to ANSI C, Richard Stallman, Jan 1987
   Split out of cpplib.c, Zack Weinberg, Oct 1998
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   Reimplemented, Neil Booth, Jul 2003
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This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3, or (at your option) any
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later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */
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#include "config.h"
#include "system.h"
#include "cpplib.h"
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#include "internal.h"
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#include "mkdeps.h"
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#include "obstack.h"
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#include "hashtab.h"
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#include "md5.h"
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#include <dirent.h>
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/* Variable length record files on VMS will have a stat size that includes
   record control characters that won't be included in the read size.  */
#ifdef VMS
# define FAB_C_VAR 2 /* variable length records (see Starlet fabdef.h) */
# define STAT_SIZE_RELIABLE(ST) ((ST).st_fab_rfm != FAB_C_VAR)
#else
# define STAT_SIZE_RELIABLE(ST) true
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#endif

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#ifdef __DJGPP__
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#include <io.h>
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  /* For DJGPP redirected input is opened in text mode.  */
#  define set_stdin_to_binary_mode() \
     if (! isatty (0)) setmode (0, O_BINARY)
#else
#  define set_stdin_to_binary_mode() /* Nothing */
#endif

/* This structure represents a file searched for by CPP, whether it
   exists or not.  An instance may be pointed to by more than one
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   cpp_file_hash_entry; at present no reference count is kept.  */
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struct _cpp_file
{
  /* Filename as given to #include or command line switch.  */
  const char *name;
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  /* The full path used to find the file.  */
  const char *path;
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  /* The full path of the pch file.  */
  const char *pchname;
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  /* The file's path with the basename stripped.  NULL if it hasn't
     been calculated yet.  */
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  const char *dir_name;
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  /* Chain through all files.  */
  struct _cpp_file *next_file;
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  /* The contents of NAME after calling read_file().  */
  const uchar *buffer;
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  /* Pointer to the real start of BUFFER.  read_file() might increment
     BUFFER; when freeing, this this pointer must be used instead.  */
  const uchar *buffer_start;

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  /* The macro, if any, preventing re-inclusion.  */
  const cpp_hashnode *cmacro;
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  /* The directory in the search path where FILE was found.  Used for
     #include_next and determining whether a header is a system
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     header.  */
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  cpp_dir *dir;
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  /* As filled in by stat(2) for the file.  */
  struct stat st;
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  /* File descriptor.  Invalid if -1, otherwise open.  */
  int fd;
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  /* Zero if this file was successfully opened and stat()-ed,
     otherwise errno obtained from failure.  */
  int err_no;
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  /* Number of times the file has been stacked for preprocessing.  */
  unsigned short stack_count;
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  /* If opened with #import or contains #pragma once.  */
  bool once_only;
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  /* If read() failed before.  */
  bool dont_read;
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  /* If this file is the main file.  */
  bool main_file;
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  /* If BUFFER above contains the true contents of the file.  */
  bool buffer_valid;
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  /* If this file is implicitly preincluded.  */
  bool implicit_preinclude;
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};
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/* A singly-linked list for all searches for a given file name, with
   its head pointed to by a slot in FILE_HASH.  The file name is what
   appeared between the quotes in a #include directive; it can be
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   determined implicitly from the hash table location or explicitly
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   from FILE->name.
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   FILE is a structure containing details about the file that was
   found with that search, or details of how the search failed.

   START_DIR is the starting location of the search in the include
   chain.  The current directories for "" includes are also hashed in
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   the hash table and therefore unique.  Files that are looked up
   without using a search path, such as absolute filenames and file
   names from the command line share a special starting directory so
   they don't cause cache hits with normal include-chain lookups.
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   If START_DIR is NULL then the entry is for a directory, not a file,
   and the directory is in DIR.  Since the starting point in a file
   lookup chain is never NULL, this means that simple pointer
   comparisons against START_DIR can be made to determine cache hits
   in file lookups.
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   If a cache lookup fails because of e.g. an extra "./" in the path,
   then nothing will break.  It is just less efficient as CPP will
   have to do more work re-preprocessing the file, and/or comparing
   its contents against earlier once-only files.
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*/
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struct cpp_file_hash_entry
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{
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  struct cpp_file_hash_entry *next;
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  cpp_dir *start_dir;
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  source_location location;
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  union
  {
    _cpp_file *file;
    cpp_dir *dir;
  } u;
};

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/* Number of entries to put in a cpp_file_hash_entry pool.  */
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#define FILE_HASH_POOL_SIZE 127

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/* A file hash entry pool.  We allocate cpp_file_hash_entry object from
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   one of these.  */
struct file_hash_entry_pool
{
  /* Number of entries used from this pool.  */
  unsigned int file_hash_entries_used;
  /* Next pool in the chain; used when freeing.  */
  struct file_hash_entry_pool *next;
  /* The memory pool.  */
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  struct cpp_file_hash_entry pool[FILE_HASH_POOL_SIZE];
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};

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static bool open_file (_cpp_file *file);
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static bool pch_open_file (cpp_reader *pfile, _cpp_file *file,
			   bool *invalid_pch);
static bool find_file_in_dir (cpp_reader *pfile, _cpp_file *file,
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			      bool *invalid_pch, source_location loc);
static bool read_file_guts (cpp_reader *pfile, _cpp_file *file,
			    source_location loc);
static bool read_file (cpp_reader *pfile, _cpp_file *file,
		       source_location loc);
static bool should_stack_file (cpp_reader *, _cpp_file *file, bool import,
			       source_location loc);
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static struct cpp_dir *search_path_head (cpp_reader *, const char *fname,
				 int angle_brackets, enum include_type);
static const char *dir_name_of_file (_cpp_file *file);
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static void open_file_failed (cpp_reader *pfile, _cpp_file *file, int,
			      source_location);
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static struct cpp_file_hash_entry *search_cache (struct cpp_file_hash_entry *head,
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					     const cpp_dir *start_dir);
static _cpp_file *make_cpp_file (cpp_reader *, cpp_dir *, const char *fname);
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static void destroy_cpp_file (_cpp_file *);
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static cpp_dir *make_cpp_dir (cpp_reader *, const char *dir_name, int sysp);
static void allocate_file_hash_entries (cpp_reader *pfile);
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static struct cpp_file_hash_entry *new_file_hash_entry (cpp_reader *pfile);
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static int report_missing_guard (void **slot, void *b);
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static hashval_t file_hash_hash (const void *p);
static int file_hash_eq (const void *p, const void *q);
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static char *read_filename_string (int ch, FILE *f);
static void read_name_map (cpp_dir *dir);
static char *remap_filename (cpp_reader *pfile, _cpp_file *file);
static char *append_file_to_dir (const char *fname, cpp_dir *dir);
static bool validate_pch (cpp_reader *, _cpp_file *file, const char *pchname);
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static int pchf_save_compare (const void *e1, const void *e2);
static int pchf_compare (const void *d_p, const void *e_p);
static bool check_file_against_entries (cpp_reader *, _cpp_file *, bool);
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/* Given a filename in FILE->PATH, with the empty string interpreted
   as <stdin>, open it.

   On success FILE contains an open file descriptor and stat
   information for the file.  On failure the file descriptor is -1 and
   the appropriate errno is also stored in FILE.  Returns TRUE iff
   successful.

   We used to open files in nonblocking mode, but that caused more
   problems than it solved.  Do take care not to acquire a controlling
   terminal by mistake (this can't happen on sane systems, but
   paranoia is a virtue).

   Use the three-argument form of open even though we aren't
   specifying O_CREAT, to defend against broken system headers.

   O_BINARY tells some runtime libraries (notably DJGPP) not to do
   newline translation; we can handle DOS line breaks just fine
   ourselves.  */
static bool
open_file (_cpp_file *file)
{
  if (file->path[0] == '\0')
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    {
      file->fd = 0;
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      set_stdin_to_binary_mode ();
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    }
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  else
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    file->fd = open (file->path, O_RDONLY | O_NOCTTY | O_BINARY, 0666);
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  if (file->fd != -1)
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    {
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      if (fstat (file->fd, &file->st) == 0)
	{
	  if (!S_ISDIR (file->st.st_mode))
	    {
	      file->err_no = 0;
	      return true;
	    }

	  /* Ignore a directory and continue the search.  The file we're
	     looking for may be elsewhere in the search path.  */
	  errno = ENOENT;
	}
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      close (file->fd);
      file->fd = -1;
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    }
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#if defined(_WIN32) && !defined(__CYGWIN__)
  else if (errno == EACCES)
    {
      /* On most UNIX systems, open succeeds on a directory.  Above,
         we check if we have opened a directory and if so, set errno
         to ENOENT.  However, on Windows, opening a directory
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         fails with EACCES.  We want to return ENOENT in that
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         case too.  */
      if (stat (file->path, &file->st) == 0
          && S_ISDIR (file->st.st_mode))
        errno = ENOENT;
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      else
	/* The call to stat may have reset errno.  */
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	errno = EACCES;
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    }
#endif    
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  else if (errno == ENOTDIR)
    errno = ENOENT;
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  file->err_no = errno;
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  return false;
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}

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/* Temporary PCH intercept of opening a file.  Try to find a PCH file
   based on FILE->name and FILE->dir, and test those found for
   validity using PFILE->cb.valid_pch.  Return true iff a valid file is
   found.  Set *INVALID_PCH if a PCH file is found but wasn't valid.  */

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static bool
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pch_open_file (cpp_reader *pfile, _cpp_file *file, bool *invalid_pch)
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{
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  static const char extension[] = ".gch";
  const char *path = file->path;
  size_t len, flen;
  char *pchname;
  struct stat st;
  bool valid = false;

  /* No PCH on <stdin> or if not requested.  */
  if (file->name[0] == '\0' || !pfile->cb.valid_pch)
    return false;
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  /* If the file is not included as first include from either the toplevel
     file or the command-line it is not a valid use of PCH.  */
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  for (_cpp_file *f = pfile->all_files; f; f = f->next_file)
    if (f->implicit_preinclude)
      continue;
    else if (f->main_file)
      break;
    else
      return false;
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  flen = strlen (path);
  len = flen + sizeof (extension);
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  pchname = XNEWVEC (char, len);
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  memcpy (pchname, path, flen);
  memcpy (pchname + flen, extension, sizeof (extension));
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  if (stat (pchname, &st) == 0)
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    {
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      DIR *pchdir;
      struct dirent *d;
      size_t dlen, plen = len;

      if (!S_ISDIR (st.st_mode))
	valid = validate_pch (pfile, file, pchname);
      else if ((pchdir = opendir (pchname)) != NULL)
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	{
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	  pchname[plen - 1] = '/';
	  while ((d = readdir (pchdir)) != NULL)
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	    {
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	      dlen = strlen (d->d_name) + 1;
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	      if ((strcmp (d->d_name, ".") == 0)
		  || (strcmp (d->d_name, "..") == 0))
		continue;
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	      if (dlen + plen > len)
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		{
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		  len += dlen + 64;
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		  pchname = XRESIZEVEC (char, pchname, len);
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		}
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	      memcpy (pchname + plen, d->d_name, dlen);
	      valid = validate_pch (pfile, file, pchname);
	      if (valid)
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		break;
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	    }
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	  closedir (pchdir);
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	}
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      if (!valid)
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	*invalid_pch = true;
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    }
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  if (valid)
    file->pchname = pchname;
  else
    free (pchname);

  return valid;
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}

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/* Canonicalize the path to FILE.  Return the canonical form if it is
   shorter, otherwise return NULL.  This function does NOT free the
   memory pointed by FILE.  */

static char *
maybe_shorter_path (const char * file)
{
  char * file2 = lrealpath (file);
  if (file2 && strlen (file2) < strlen (file))
    {
      return file2;
    }
  else 
    {
      free (file2);
      return NULL;
    }
}

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/* Try to open the path FILE->name appended to FILE->dir.  This is
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   where remap and PCH intercept the file lookup process.  Return true
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   if the file was found, whether or not the open was successful.
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   Set *INVALID_PCH to true if a PCH file is found but wasn't valid.
   Use LOC when emitting any diagnostics.  */
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static bool
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find_file_in_dir (cpp_reader *pfile, _cpp_file *file, bool *invalid_pch,
		  source_location loc)
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{
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  char *path;
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  if (CPP_OPTION (pfile, remap) && (path = remap_filename (pfile, file)))
    ;
  else
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    if (file->dir->construct)
      path = file->dir->construct (file->name, file->dir);
    else
      path = append_file_to_dir (file->name, file->dir);
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  if (path)
    {
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      hashval_t hv;
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      char *copy;
      void **pp;

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      /* We try to canonicalize system headers.  For DOS based file
       * system, we always try to shorten non-system headers, as DOS
       * has a tighter constraint on max path length.  */
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      if ((CPP_OPTION (pfile, canonical_system_headers) && file->dir->sysp)
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#ifdef HAVE_DOS_BASED_FILE_SYSTEM
	  || !file->dir->sysp
#endif
	 )
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	{
	  char * canonical_path = maybe_shorter_path (path);
	  if (canonical_path)
	    {
	      /* The canonical path was newly allocated.  Let's free the
		 non-canonical one.  */
	      free (path);
	      path = canonical_path;
	    }
	}

      hv = htab_hash_string (path);
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      if (htab_find_with_hash (pfile->nonexistent_file_hash, path, hv) != NULL)
	{
	  file->err_no = ENOENT;
	  return false;
	}

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      file->path = path;
      if (pch_open_file (pfile, file, invalid_pch))
	return true;
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      if (open_file (file))
	return true;

      if (file->err_no != ENOENT)
	{
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	  open_file_failed (pfile, file, 0, loc);
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	  return true;
	}

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      /* We copy the path name onto an obstack partly so that we don't
	 leak the memory, but mostly so that we don't fragment the
	 heap.  */
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      copy = (char *) obstack_copy0 (&pfile->nonexistent_file_ob, path,
				     strlen (path));
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      free (path);
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      pp = htab_find_slot_with_hash (pfile->nonexistent_file_hash,
				     copy, hv, INSERT);
      *pp = copy;

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      file->path = file->name;
    }
  else
    {
      file->err_no = ENOENT; 
      file->path = NULL;
    }

  return false;
}
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/* Return tue iff the missing_header callback found the given HEADER.  */
static bool
search_path_exhausted (cpp_reader *pfile, const char *header, _cpp_file *file)
{
  missing_header_cb func = pfile->cb.missing_header;

  /* When the regular search path doesn't work, try context dependent
     headers search paths.  */
  if (func
      && file->dir == NULL)
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    {
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      if ((file->path = func (pfile, header, &file->dir)) != NULL)
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	{
	  if (open_file (file))
	    return true;
	  free ((void *)file->path);
	}
      file->path = file->name;
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    }

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  return false;
}

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bool
_cpp_find_failed (_cpp_file *file)
{
  return file->err_no != 0;
}

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/* Given a filename FNAME search for such a file in the include path
   starting from START_DIR.  If FNAME is the empty string it is
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   interpreted as STDIN if START_DIR is PFILE->no_search_path.
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   If the file is not found in the file cache fall back to the O/S and
   add the result to our cache.

   If the file was not found in the filesystem, or there was an error
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   opening it, then ERR_NO is nonzero and FD is -1.  If the file was
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   found, then ERR_NO is zero and FD could be -1 or an open file
   descriptor.  FD can be -1 if the file was found in the cache and
   had previously been closed.  To open it again pass the return value
   to open_file().
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   If IMPLICIT_PREINCLUDE then it is OK for the file to be missing.
   If present, it is OK for a precompiled header to be included after
   it.
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   Use LOC as the location for any errors.  */

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_cpp_file *
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_cpp_find_file (cpp_reader *pfile, const char *fname, cpp_dir *start_dir,
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		bool fake, int angle_brackets, bool implicit_preinclude,
		source_location loc)
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{
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  struct cpp_file_hash_entry *entry;
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  void **hash_slot;
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  _cpp_file *file;
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  bool invalid_pch = false;
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  bool saw_bracket_include = false;
  bool saw_quote_include = false;
  struct cpp_dir *found_in_cache = NULL;
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  /* Ensure we get no confusion between cached files and directories.  */
  if (start_dir == NULL)
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    cpp_error_at (pfile, CPP_DL_ICE, loc, "NULL directory in find_file");
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  hash_slot
    = htab_find_slot_with_hash (pfile->file_hash, fname,
				htab_hash_string (fname), INSERT);
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  /* First check the cache before we resort to memory allocation.  */
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  entry = search_cache ((struct cpp_file_hash_entry *) *hash_slot, start_dir);
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  if (entry)
    return entry->u.file;

  file = make_cpp_file (pfile, start_dir, fname);
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  file->implicit_preinclude
    = (implicit_preinclude
       || (pfile->buffer
	   && pfile->buffer->file->implicit_preinclude));
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  /* Try each path in the include chain.  */
  for (; !fake ;)
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    {
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      if (find_file_in_dir (pfile, file, &invalid_pch, loc))
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	break;

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      file->dir = file->dir->next;
      if (file->dir == NULL)
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	{
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	  if (search_path_exhausted (pfile, fname, file))
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	    {
	      /* Although this file must not go in the cache, because
		 the file found might depend on things (like the current file)
		 that aren't represented in the cache, it still has to go in
		 the list of all files so that #import works.  */
	      file->next_file = pfile->all_files;
	      pfile->all_files = file;
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	      if (*hash_slot == NULL)
		{
		  /* If *hash_slot is NULL, the above htab_find_slot_with_hash
		     call just created the slot, but we aren't going to store
		     there anything, so need to remove the newly created entry.
		     htab_clear_slot requires that it is non-NULL, so store
		     there some non-NULL pointer, htab_clear_slot will
		     overwrite it immediately.  */
		  *hash_slot = file;
		  htab_clear_slot (pfile->file_hash, hash_slot);
		}
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	      return file;
	    }
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	  if (invalid_pch)
	    {
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	      cpp_error (pfile, CPP_DL_ERROR,
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	       "one or more PCH files were found, but they were invalid");
	      if (!cpp_get_options (pfile)->warn_invalid_pch)
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		cpp_error (pfile, CPP_DL_ERROR,
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			   "use -Winvalid-pch for more information");
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	    }
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	  if (implicit_preinclude)
	    {
	      free ((char *) file->name);
	      free (file);
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	      if (*hash_slot == NULL)
		{
		  /* See comment on the above htab_clear_slot call.  */
		  *hash_slot = file;
		  htab_clear_slot (pfile->file_hash, hash_slot);
		}
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	      return NULL;
	    }
	  else
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	    open_file_failed (pfile, file, angle_brackets, loc);
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	  break;
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	}
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      /* Only check the cache for the starting location (done above)
	 and the quote and bracket chain heads because there are no
	 other possible starting points for searches.  */
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      if (file->dir == pfile->bracket_include)
	saw_bracket_include = true;
      else if (file->dir == pfile->quote_include)
	saw_quote_include = true;
      else
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	continue;
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      entry = search_cache ((struct cpp_file_hash_entry *) *hash_slot, file->dir);
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      if (entry)
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	{
	  found_in_cache = file->dir;
	  break;
	}
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    }
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  if (entry)
    {
      /* Cache for START_DIR too, sharing the _cpp_file structure.  */
      free ((char *) file->name);
      free (file);
      file = entry->u.file;
    }
  else
    {
      /* This is a new file; put it in the list.  */
      file->next_file = pfile->all_files;
      pfile->all_files = file;
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    }

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  /* Store this new result in the hash table.  */
  entry = new_file_hash_entry (pfile);
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  entry->next = (struct cpp_file_hash_entry *) *hash_slot;
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  entry->start_dir = start_dir;
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  entry->location = pfile->line_table->highest_location;
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  entry->u.file = file;
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  *hash_slot = (void *) entry;
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  /* If we passed the quote or bracket chain heads, cache them also.
     This speeds up processing if there are lots of -I options.  */
  if (saw_bracket_include
      && pfile->bracket_include != start_dir
      && found_in_cache != pfile->bracket_include)
    {
      entry = new_file_hash_entry (pfile);
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      entry->next = (struct cpp_file_hash_entry *) *hash_slot;
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      entry->start_dir = pfile->bracket_include;
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      entry->location = pfile->line_table->highest_location;
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      entry->u.file = file;
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      *hash_slot = (void *) entry;
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    }
  if (saw_quote_include
      && pfile->quote_include != start_dir
      && found_in_cache != pfile->quote_include)
    {
      entry = new_file_hash_entry (pfile);
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      entry->next = (struct cpp_file_hash_entry *) *hash_slot;
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      entry->start_dir = pfile->quote_include;
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      entry->location = pfile->line_table->highest_location;
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      entry->u.file = file;
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      *hash_slot = (void *) entry;
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    }

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  return file;
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}

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/* Read a file into FILE->buffer, returning true on success.
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   If FILE->fd is something weird, like a block device, we don't want
   to read it at all.  Don't even try to figure out what something is,
   except for plain files and block devices, since there is no
   reliable portable way of doing this.
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   Use LOC for any diagnostics.

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   FIXME: Flush file cache and try again if we run out of memory.  */
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static bool
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read_file_guts (cpp_reader *pfile, _cpp_file *file, source_location loc)
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{
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  ssize_t size, total, count;
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  uchar *buf;
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  bool regular;
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  if (S_ISBLK (file->st.st_mode))
    {
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      cpp_error_at (pfile, CPP_DL_ERROR, loc,
		    "%s is a block device", file->path);
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      return false;
    }
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687
  regular = S_ISREG (file->st.st_mode) != 0;
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  if (regular)
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    {
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      /* off_t might have a wider range than ssize_t - in other words,
	 the max size of a file might be bigger than the address
	 space.  We can't handle a file that large.  (Anyone with
	 a single source file bigger than 2GB needs to rethink
	 their coding style.)  Some systems (e.g. AIX 4.1) define
	 SSIZE_MAX to be much smaller than the actual range of the
	 type.  Use INTTYPE_MAXIMUM unconditionally to ensure this
	 does not bite us.  */
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      if (file->st.st_size > INTTYPE_MAXIMUM (ssize_t))
699
	{
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	  cpp_error_at (pfile, CPP_DL_ERROR, loc,
			"%s is too large", file->path);
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	  return false;
703
	}
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      size = file->st.st_size;
    }
  else
    /* 8 kilobytes is a sensible starting size.  It ought to be bigger
       than the kernel pipe buffer, and it's definitely bigger than
       the majority of C source files.  */
    size = 8 * 1024;

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  /* The + 16 here is space for the final '\n' and 15 bytes of padding,
     used to quiet warnings from valgrind or Address Sanitizer, when the
     optimized lexer accesses aligned 16-byte memory chunks, including
     the bytes after the malloced, area, and stops lexing on '\n'.  */
  buf = XNEWVEC (uchar, size + 16);
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  total = 0;
  while ((count = read (file->fd, buf + total, size - total)) > 0)
    {
      total += count;

      if (total == size)
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	{
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	  if (regular)
	    break;
	  size *= 2;
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	  buf = XRESIZEVEC (uchar, buf, size + 16);
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	}
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    }
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  if (count < 0)
733
    {
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      cpp_errno_filename (pfile, CPP_DL_ERROR, file->path, loc);
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      free (buf);
736
      return false;
737
    }
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  if (regular && total != size && STAT_SIZE_RELIABLE (file->st))
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    cpp_error_at (pfile, CPP_DL_WARNING, loc,
741
	       "%s is shorter than expected", file->path);
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  file->buffer = _cpp_convert_input (pfile,
				     CPP_OPTION (pfile, input_charset),
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				     buf, size + 16, total,
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				     &file->buffer_start,
				     &file->st.st_size);
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  file->buffer_valid = true;

  return true;
}

/* Convenience wrapper around read_file_guts that opens the file if
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   necessary and closes the file descriptor after reading.  FILE must
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   have been passed through find_file() at some stage.  Use LOC for
   any diagnostics.  */
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static bool
758
read_file (cpp_reader *pfile, _cpp_file *file, source_location loc)
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{
  /* If we already have its contents in memory, succeed immediately.  */
  if (file->buffer_valid)
    return true;
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  /* If an earlier read failed for some reason don't try again.  */
  if (file->dont_read || file->err_no)
    return false;
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  if (file->fd == -1 && !open_file (file))
    {
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      open_file_failed (pfile, file, 0, loc);
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      return false;
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    }
Zack Weinberg committed
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  file->dont_read = !read_file_guts (pfile, file, loc);
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  close (file->fd);
  file->fd = -1;
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  return !file->dont_read;
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}

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/* Returns TRUE if FILE's contents have been successfully placed in
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   FILE->buffer and the file should be stacked, otherwise false.
   Use LOC for any diagnostics.  */
784
static bool
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should_stack_file (cpp_reader *pfile, _cpp_file *file, bool import,
		   source_location loc)
787
{
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  _cpp_file *f;
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  /* Skip once-only files.  */
  if (file->once_only)
    return false;

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  /* We must mark the file once-only if #import now, before header
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     guard checks.  Otherwise, undefining the header guard might
     cause the file to be re-stacked.  */
  if (import)
    {
      _cpp_mark_file_once_only (pfile, file);

      /* Don't stack files that have been stacked before.  */
      if (file->stack_count)
	return false;
    }

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  /* Skip if the file had a header guard and the macro is defined.
     PCH relies on this appearing before the PCH handler below.  */
  if (file->cmacro && file->cmacro->type == NT_MACRO)
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    return false;

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  /* Handle PCH files immediately; don't stack them.  */
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  if (file->pchname)
813
    {
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      pfile->cb.read_pch (pfile, file->pchname, file->fd, file->path);
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      file->fd = -1;
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      free ((void *) file->pchname);
      file->pchname = NULL;
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      return false;
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    }
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  if (!read_file (pfile, file, loc))
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    return false;
823

Geoffrey Keating committed
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  /* Check the file against the PCH file.  This is done before
     checking against files we've already seen, since it may save on
     I/O.  */
  if (check_file_against_entries (pfile, file, import))
    {
      /* If this isn't a #import, but yet we can't include the file,
	 that means that it was #import-ed in the PCH file,
	 so we can never include it again.  */
      if (! import)
	_cpp_mark_file_once_only (pfile, file);
      return false;
    }

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  /* Now we've read the file's contents, we can stack it if there
     are no once-only files.  */
  if (!pfile->seen_once_only)
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    return true;

842
  /* We may have read the file under a different name.  Look
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     for likely candidates and compare file contents to be sure.  */
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  for (f = pfile->all_files; f; f = f->next_file)
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    {
      if (f == file)
	continue;

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      if ((import || f->once_only)
	  && f->err_no == 0
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	  && f->st.st_mtime == file->st.st_mtime
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	  && f->st.st_size == file->st.st_size)
	{
	  _cpp_file *ref_file;
	  bool same_file_p = false;

	  if (f->buffer && !f->buffer_valid)
	    {
	      /* We already have a buffer but it is not valid, because
		 the file is still stacked.  Make a new one.  */
	      ref_file = make_cpp_file (pfile, f->dir, f->name);
	      ref_file->path = f->path;
	    }
	  else
	    /* The file is not stacked anymore.  We can reuse it.  */
	    ref_file = f;

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	  same_file_p = read_file (pfile, ref_file, loc)
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			/* Size might have changed in read_file().  */
			&& ref_file->st.st_size == file->st.st_size
			&& !memcmp (ref_file->buffer,
				    file->buffer,
				    file->st.st_size);

	  if (f->buffer && !f->buffer_valid)
	    {
	      ref_file->path = 0;
	      destroy_cpp_file (ref_file);
	    }

	  if (same_file_p)
	    break;
	}
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    }
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  return f == NULL;
}

/* Place the file referenced by FILE into a new buffer on the buffer
   stack if possible.  IMPORT is true if this stacking attempt is
   because of a #import directive.  Returns true if a buffer is
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   stacked.  Use LOC for any diagnostics.  */
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bool
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_cpp_stack_file (cpp_reader *pfile, _cpp_file *file, bool import,
		 source_location loc)
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{
  cpp_buffer *buffer;
  int sysp;

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  if (!should_stack_file (pfile, file, import, loc))
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      return false;

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  if (pfile->buffer == NULL || file->dir == NULL)
    sysp = 0;
  else
    sysp = MAX (pfile->buffer->sysp,  file->dir->sysp);
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  /* Add the file to the dependencies on its first inclusion.  */
  if (CPP_OPTION (pfile, deps.style) > !!sysp && !file->stack_count)
    {
      if (!file->main_file || !CPP_OPTION (pfile, deps.ignore_main_file))
	deps_add_dep (pfile->deps, file->path);
    }

  /* Clear buffer_valid since _cpp_clean_line messes it up.  */
  file->buffer_valid = false;
  file->stack_count++;

  /* Stack the buffer.  */
  buffer = cpp_push_buffer (pfile, file->buffer, file->st.st_size,
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			    CPP_OPTION (pfile, preprocessed)
			    && !CPP_OPTION (pfile, directives_only));
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  buffer->file = file;
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  buffer->sysp = sysp;
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  buffer->to_free = file->buffer_start;
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  /* Initialize controlling macro state.  */
  pfile->mi_valid = true;
  pfile->mi_cmacro = 0;

  /* Generate the call back.  */
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  _cpp_do_file_change (pfile, LC_ENTER, file->path, 1, sysp);
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  return true;
Zack Weinberg committed
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}

937
/* Mark FILE to be included once only.  */
938
void
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_cpp_mark_file_once_only (cpp_reader *pfile, _cpp_file *file)
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{
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  pfile->seen_once_only = true;
  file->once_only = true;
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}

/* Return the directory from which searching for FNAME should start,
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   considering the directive TYPE and ANGLE_BRACKETS.  If there is
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   nothing left in the path, returns NULL.  */
static struct cpp_dir *
search_path_head (cpp_reader *pfile, const char *fname, int angle_brackets,
		  enum include_type type)
{
  cpp_dir *dir;
  _cpp_file *file;
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955
  if (IS_ABSOLUTE_PATH (fname))
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    return &pfile->no_search_path;

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  /* pfile->buffer is NULL when processing an -include command-line flag.  */
  file = pfile->buffer == NULL ? pfile->main_file : pfile->buffer->file;
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  /* For #include_next, skip in the search path past the dir in which
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     the current file was found, but if it was found via an absolute
     path use the normal search logic.  */
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  if (type == IT_INCLUDE_NEXT && file->dir
      && file->dir != &pfile->no_search_path)
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    dir = file->dir->next;
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  else if (angle_brackets)
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    dir = pfile->bracket_include;
  else if (type == IT_CMDLINE)
    /* -include and -imacros use the #include "" chain with the
       preprocessor's cwd prepended.  */
    return make_cpp_dir (pfile, "./", false);
  else if (pfile->quote_ignores_source_dir)
    dir = pfile->quote_include;
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  else
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    return make_cpp_dir (pfile, dir_name_of_file (file),
			 pfile->buffer ? pfile->buffer->sysp : 0);
978 979

  if (dir == NULL)
980
    cpp_error (pfile, CPP_DL_ERROR,
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	       "no include path in which to search for %s", fname);

  return dir;
}
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986
/* Strip the basename from the file's path.  It ends with a slash if
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   of nonzero length.  Note that this procedure also works for
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   <stdin>, which is represented by the empty string.  */
static const char *
dir_name_of_file (_cpp_file *file)
{
  if (!file->dir_name)
993
    {
994
      size_t len = lbasename (file->path) - file->path;
995
      char *dir_name = XNEWVEC (char, len + 1);
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      memcpy (dir_name, file->path, len);
      dir_name[len] = '\0';
      file->dir_name = dir_name;
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    }

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  return file->dir_name;
}

/* Handles #include-family directives (distinguished by TYPE),
   including HEADER, and the command line -imacros and -include.
   Returns true if a buffer was stacked.  */
bool
_cpp_stack_include (cpp_reader *pfile, const char *fname, int angle_brackets,
1010
		    enum include_type type, source_location loc)
1011 1012
{
  struct cpp_dir *dir;
1013
  _cpp_file *file;
1014
  bool stacked;
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  /* For -include command-line flags we have type == IT_CMDLINE.
     When the first -include file is processed we have the case, where
     pfile->cur_token == pfile->cur_run->base, we are directly called up
     by the front end.  However in the case of the second -include file,
     we are called from _cpp_lex_token -> _cpp_get_fresh_line ->
     cpp_push_include, with pfile->cur_token != pfile->cur_run->base,
     and pfile->cur_token[-1].src_loc not (yet) initialized.
     However, when the include file cannot be found, we need src_loc to
     be initialized to some safe value: 0 means UNKNOWN_LOCATION.  */
  if (type == IT_CMDLINE && pfile->cur_token != pfile->cur_run->base)
    pfile->cur_token[-1].src_loc = 0;

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  dir = search_path_head (pfile, fname, angle_brackets, type);
  if (!dir)
    return false;

Joseph Myers committed
1032
  file = _cpp_find_file (pfile, fname, dir, false, angle_brackets,
1033
			 type == IT_DEFAULT, loc);
Joseph Myers committed
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  if (type == IT_DEFAULT && file == NULL)
    return false;
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  /* Compensate for the increment in linemap_add that occurs if
      _cpp_stack_file actually stacks the file.  In the case of a
     normal #include, we're currently at the start of the line
     *following* the #include.  A separate source_location for this
     location makes no sense (until we do the LC_LEAVE), and
     complicates LAST_SOURCE_LINE_LOCATION.  This does not apply if we
     found a PCH file (in which case linemap_add is not called) or we
     were included from the command-line.  */
Joseph Myers committed
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  if (file->pchname == NULL && file->err_no == 0
      && type != IT_CMDLINE && type != IT_DEFAULT)
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    pfile->line_table->highest_location--;

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  stacked = _cpp_stack_file (pfile, file, type == IT_IMPORT, loc);
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  if (!stacked)
    /* _cpp_stack_file didn't stack the file, so let's rollback the
       compensation dance we performed above.  */
    pfile->line_table->highest_location++;

  return stacked;
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}

/* Could not open FILE.  The complication is dependency output.  */
static void
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open_file_failed (cpp_reader *pfile, _cpp_file *file, int angle_brackets,
		  source_location loc)
1063
{
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  int sysp = pfile->line_table->highest_line > 1 && pfile->buffer ? pfile->buffer->sysp : 0;
James E Wilson committed
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  bool print_dep = CPP_OPTION (pfile, deps.style) > (angle_brackets || !!sysp);
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  if (pfile->state.in__has_include__)
    return;

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  errno = file->err_no;
  if (print_dep && CPP_OPTION (pfile, deps.missing_files) && errno == ENOENT)
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    {
      deps_add_dep (pfile->deps, file->name);
      /* If the preprocessor output (other than dependency information) is
         being used, we must also flag an error.  */
      if (CPP_OPTION (pfile, deps.need_preprocessor_output))
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	cpp_errno_filename (pfile, CPP_DL_FATAL,
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			    file->path ? file->path : file->name,
			    loc);
1080
    }
1081
  else
Zack Weinberg committed
1082
    {
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      /* If we are not outputting dependencies, or if we are and dependencies
         were requested for this file, or if preprocessor output is needed
         in addition to dependency information, this is an error.

         Otherwise (outputting dependencies but not for this file, and not
         using the preprocessor output), we can still produce correct output
         so it's only a warning.  */
      if (CPP_OPTION (pfile, deps.style) == DEPS_NONE
          || print_dep
          || CPP_OPTION (pfile, deps.need_preprocessor_output))
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	cpp_errno_filename (pfile, CPP_DL_FATAL,
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			    file->path ? file->path : file->name,
			    loc);
1096
      else
1097
	cpp_errno_filename (pfile, CPP_DL_WARNING,
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			    file->path ? file->path : file->name,
			    loc);
Zack Weinberg committed
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    }
1101
}
1102

1103 1104
/* Search in the chain beginning at HEAD for a file whose search path
   started at START_DIR != NULL.  */
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static struct cpp_file_hash_entry *
search_cache (struct cpp_file_hash_entry *head, const cpp_dir *start_dir)
1107
{
1108 1109 1110 1111
  while (head && head->start_dir != start_dir)
    head = head->next;

  return head;
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}

/* Allocate a new _cpp_file structure.  */
static _cpp_file *
make_cpp_file (cpp_reader *pfile, cpp_dir *dir, const char *fname)
{
  _cpp_file *file;

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  file = XCNEW (_cpp_file);
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  file->main_file = !pfile->buffer;
  file->fd = -1;
  file->dir = dir;
  file->name = xstrdup (fname);

  return file;
}

1129 1130 1131 1132
/* Release a _cpp_file structure.  */
static void
destroy_cpp_file (_cpp_file *file)
{
1133
  free ((void *) file->buffer_start);
1134
  free ((void *) file->name);
1135
  free ((void *) file->path);
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  free (file);
}

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/* Release all the files allocated by this reader.  */
static void
destroy_all_cpp_files (cpp_reader *pfile)
{
  _cpp_file *iter = pfile->all_files;
  while (iter)
    {
      _cpp_file *next = iter->next_file;
      destroy_cpp_file (iter);
      iter = next;
    }
}

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/* A hash of directory names.  The directory names are the path names
   of files which contain a #include "", the included file name is
   appended to this directories.

   To avoid duplicate entries we follow the convention that all
   non-empty directory names should end in a '/'.  DIR_NAME must be
   stored in permanently allocated memory.  */
static cpp_dir *
make_cpp_dir (cpp_reader *pfile, const char *dir_name, int sysp)
{
1162
  struct cpp_file_hash_entry *entry, **hash_slot;
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  cpp_dir *dir;

1165
  hash_slot = (struct cpp_file_hash_entry **)
1166
    htab_find_slot_with_hash (pfile->dir_hash, dir_name,
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			      htab_hash_string (dir_name),
			      INSERT);
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  /* Have we already hashed this directory?  */
  for (entry = *hash_slot; entry; entry = entry->next)
    if (entry->start_dir == NULL)
      return entry->u.dir;

1175
  dir = XCNEW (cpp_dir);
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  dir->next = pfile->quote_include;
  dir->name = (char *) dir_name;
  dir->len = strlen (dir_name);
  dir->sysp = sysp;
1180
  dir->construct = 0;
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  /* Store this new result in the hash table.  */
  entry = new_file_hash_entry (pfile);
  entry->next = *hash_slot;
  entry->start_dir = NULL;
1186
  entry->location = pfile->line_table->highest_location;
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  entry->u.dir = dir;
  *hash_slot = entry;

  return dir;
}

/* Create a new block of memory for file hash entries.  */
static void
allocate_file_hash_entries (cpp_reader *pfile)
{
1197 1198 1199 1200
  struct file_hash_entry_pool *pool = XNEW (struct file_hash_entry_pool);
  pool->file_hash_entries_used = 0;
  pool->next = pfile->file_hash_entries;
  pfile->file_hash_entries = pool;
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}

/* Return a new file hash entry.  */
1204
static struct cpp_file_hash_entry *
1205 1206
new_file_hash_entry (cpp_reader *pfile)
{
1207 1208
  unsigned int idx;
  if (pfile->file_hash_entries->file_hash_entries_used == FILE_HASH_POOL_SIZE)
1209 1210
    allocate_file_hash_entries (pfile);

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  idx = pfile->file_hash_entries->file_hash_entries_used++;
  return &pfile->file_hash_entries->pool[idx];
}

/* Free the file hash entry pools.  */
static void
free_file_hash_entries (cpp_reader *pfile)
{
  struct file_hash_entry_pool *iter = pfile->file_hash_entries;
  while (iter)
    {
      struct file_hash_entry_pool *next = iter->next;
      free (iter);
      iter = next;
    }
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}

/* Returns TRUE if a file FNAME has ever been successfully opened.
   This routine is not intended to correctly handle filenames aliased
   by links or redundant . or .. traversals etc.  */
bool
cpp_included (cpp_reader *pfile, const char *fname)
{
1234
  struct cpp_file_hash_entry *entry;
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1236
  entry = (struct cpp_file_hash_entry *)
1237
     htab_find_with_hash (pfile->file_hash, fname, htab_hash_string (fname));
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  while (entry && (entry->start_dir == NULL || entry->u.file->err_no))
    entry = entry->next;

  return entry != NULL;
}

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/* Returns TRUE if a file FNAME has ever been successfully opened
   before LOCATION.  This routine is not intended to correctly handle
   filenames aliased by links or redundant . or .. traversals etc.  */
bool
cpp_included_before (cpp_reader *pfile, const char *fname,
		     source_location location)
{
1252 1253 1254
  struct cpp_file_hash_entry *entry
    = (struct cpp_file_hash_entry *)
      htab_find_with_hash (pfile->file_hash, fname, htab_hash_string (fname));
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1256 1257
  if (IS_ADHOC_LOC (location))
    location = get_location_from_adhoc_loc (pfile->line_table, location);
1258 1259 1260 1261 1262 1263 1264 1265

  while (entry && (entry->start_dir == NULL || entry->u.file->err_no
		   || entry->location > location))
    entry = entry->next;

  return entry != NULL;
}

1266
/* Calculate the hash value of a file hash entry P.  */
1267 1268 1269 1270

static hashval_t
file_hash_hash (const void *p)
{
1271
  struct cpp_file_hash_entry *entry = (struct cpp_file_hash_entry *) p;
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  const char *hname;
  if (entry->start_dir)
    hname = entry->u.file->name;
  else
    hname = entry->u.dir->name;

  return htab_hash_string (hname);
}

1281 1282
/* Compare a string Q against a file hash entry P.  */
static int
1283
file_hash_eq (const void *p, const void *q)
1284
{
1285
  struct cpp_file_hash_entry *entry = (struct cpp_file_hash_entry *) p;
1286 1287 1288 1289 1290 1291 1292 1293
  const char *fname = (const char *) q;
  const char *hname;

  if (entry->start_dir)
    hname = entry->u.file->name;
  else
    hname = entry->u.dir->name;

1294
  return filename_cmp (hname, fname) == 0;
1295 1296
}

1297 1298 1299 1300 1301
/* Compare entries in the nonexistent file hash table.  These are just
   strings.  */
static int
nonexistent_file_hash_eq (const void *p, const void *q)
{
1302
  return filename_cmp ((const char *) p, (const char *) q) == 0;
1303 1304
}

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/* Initialize everything in this source file.  */
void
_cpp_init_files (cpp_reader *pfile)
{
1309
  pfile->file_hash = htab_create_alloc (127, file_hash_hash, file_hash_eq,
1310
					NULL, xcalloc, free);
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  pfile->dir_hash = htab_create_alloc (127, file_hash_hash, file_hash_eq,
					NULL, xcalloc, free);
1313
  allocate_file_hash_entries (pfile);
1314 1315 1316
  pfile->nonexistent_file_hash = htab_create_alloc (127, htab_hash_string,
						    nonexistent_file_hash_eq,
						    NULL, xcalloc, free);
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  obstack_specify_allocation (&pfile->nonexistent_file_ob, 0, 0,
			      xmalloc, free);
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}

/* Finalize everything in this source file.  */
void
_cpp_cleanup_files (cpp_reader *pfile)
{
  htab_delete (pfile->file_hash);
1326
  htab_delete (pfile->dir_hash);
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  htab_delete (pfile->nonexistent_file_hash);
  obstack_free (&pfile->nonexistent_file_ob, 0);
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  free_file_hash_entries (pfile);
  destroy_all_cpp_files (pfile);
}

/* Make the parser forget about files it has seen.  This can be useful
   for resetting the parser to start another run.  */
void
cpp_clear_file_cache (cpp_reader *pfile)
{
  _cpp_cleanup_files (pfile);
  pfile->file_hash_entries = NULL;
  pfile->all_files = NULL;
  _cpp_init_files (pfile);
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}

/* Enter a file name in the hash for the sake of cpp_included.  */
void
_cpp_fake_include (cpp_reader *pfile, const char *fname)
{
1348
  _cpp_find_file (pfile, fname, pfile->buffer->file->dir, true, 0, false, 0);
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}

1351
/* Not everyone who wants to set system-header-ness on a buffer can
1352 1353
   see the details of a buffer.  This is an exported interface because
   fix-header needs it.  */
1354
void
1355
cpp_make_system_header (cpp_reader *pfile, int syshdr, int externc)
1356
{
1357
  int flags = 0;
1358
  const struct line_maps *line_table = pfile->line_table;
1359
  const line_map_ordinary *map = LINEMAPS_LAST_ORDINARY_MAP (line_table);
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  /* 1 = system header, 2 = system header to be treated as C.  */
  if (syshdr)
    flags = 1 + (externc != 0);
1363
  pfile->buffer->sysp = flags;
1364
  _cpp_do_file_change (pfile, LC_RENAME, ORDINARY_MAP_FILE_NAME (map),
1365
		       SOURCE_LINE (map, pfile->line_table->highest_line), flags);
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}

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/* Allow the client to change the current file.  Used by the front end
   to achieve pseudo-file names like <built-in>.
   If REASON is LC_LEAVE, then NEW_NAME must be NULL.  */
1371
void
1372 1373
cpp_change_file (cpp_reader *pfile, enum lc_reason reason,
		 const char *new_name)
1374
{
1375
  _cpp_do_file_change (pfile, reason, new_name, 1, 0);
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}

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struct report_missing_guard_data
{
  const char **paths;
  size_t count;
};

1384
/* Callback function for htab_traverse.  */
1385
static int
1386
report_missing_guard (void **slot, void *d)
1387
{
1388
  struct cpp_file_hash_entry *entry = (struct cpp_file_hash_entry *) *slot;
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  struct report_missing_guard_data *data
    = (struct report_missing_guard_data *) d;
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1392 1393
  /* Skip directories.  */
  if (entry->start_dir != NULL)
1394
    {
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      _cpp_file *file = entry->u.file;

      /* We don't want MI guard advice for the main file.  */
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      if (!file->once_only && file->cmacro == NULL
	  && file->stack_count == 1 && !file->main_file)
1400
	{
1401
	  if (data->paths == NULL)
1402
	    {
1403 1404
	      data->paths = XCNEWVEC (const char *, data->count);
	      data->count = 0;
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	    }

1407
	  data->paths[data->count++] = file->path;
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	}
    }

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  /* Keep traversing the hash table.  */
  return 1;
}

/* Comparison function for qsort.  */
static int
report_missing_guard_cmp (const void *p1, const void *p2)
{
  return strcmp (*(const char *const *) p1, *(const char *const *) p2);
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}

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/* Report on all files that might benefit from a multiple include guard.
   Triggered by -H.  */
void
_cpp_report_missing_guards (cpp_reader *pfile)
1426
{
1427 1428 1429 1430 1431
  struct report_missing_guard_data data;

  data.paths = NULL;
  data.count = htab_elements (pfile->file_hash);
  htab_traverse (pfile->file_hash, report_missing_guard, &data);
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1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449
  if (data.paths != NULL)
    {
      size_t i;

      /* Sort the paths to avoid outputting them in hash table
	 order.  */
      qsort (data.paths, data.count, sizeof (const char *),
	     report_missing_guard_cmp);
      fputs (_("Multiple include guards may be useful for:\n"),
	     stderr);
      for (i = 0; i < data.count; i++)
	{
	  fputs (data.paths[i], stderr);
	  putc ('\n', stderr);
	}
      free (data.paths);
    }
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}

1452
/* Locate HEADER, and determine whether it is newer than the current
1453
   file.  If it cannot be located or dated, return -1, if it is
1454
   newer, return 1, otherwise 0.  */
1455
int
1456 1457
_cpp_compare_file_date (cpp_reader *pfile, const char *fname,
			int angle_brackets)
1458
{
1459 1460
  _cpp_file *file;
  struct cpp_dir *dir;
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1462 1463
  dir = search_path_head (pfile, fname, angle_brackets, IT_INCLUDE);
  if (!dir)
1464
    return -1;
1465

1466
  file = _cpp_find_file (pfile, fname, dir, false, angle_brackets, false, 0);
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  if (file->err_no)
    return -1;
1469

1470
  if (file->fd != -1)
1471
    {
1472 1473
      close (file->fd);
      file->fd = -1;
1474
    }
Zack Weinberg committed
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1476
  return file->st.st_mtime > pfile->buffer->file->st.st_mtime;
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}

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/* Pushes the given file onto the buffer stack.  Returns nonzero if
   successful.  */
bool
1482
cpp_push_include (cpp_reader *pfile, const char *fname)
1483
{
1484
  return _cpp_stack_include (pfile, fname, false, IT_CMDLINE, 0);
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}

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/* Pushes the given file, implicitly included at the start of a
   compilation, onto the buffer stack but without any errors if the
   file is not found.  Returns nonzero if successful.  */
bool
cpp_push_default_include (cpp_reader *pfile, const char *fname)
{
1493
  return _cpp_stack_include (pfile, fname, true, IT_DEFAULT, 0);
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}

1496
/* Do appropriate cleanup when a file INC's buffer is popped off the
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   input stack.  */
void
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_cpp_pop_file_buffer (cpp_reader *pfile, _cpp_file *file,
		      const unsigned char *to_free)
1501
{
1502
  /* Record the inclusion-preventing macro, which could be NULL
1503
     meaning no controlling macro.  */
1504 1505
  if (pfile->mi_valid && file->cmacro == NULL)
    file->cmacro = pfile->mi_cmacro;
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1506 1507

  /* Invalidate control macros in the #including file.  */
1508
  pfile->mi_valid = false;
1509

1510
  if (to_free)
1511
    {
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      if (to_free == file->buffer_start)
	{
	  file->buffer_start = NULL;
	  file->buffer = NULL;
	  file->buffer_valid = false;
	}
      free ((void *) to_free);
1519
    }
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}

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/* Return the file name associated with FILE.  */
const char *
_cpp_get_file_name (_cpp_file *file)
{
  return file->name;
}

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/* Inteface to file statistics record in _cpp_file structure. */
struct stat *
_cpp_get_file_stat (_cpp_file *file)
{
    return &file->st;
}

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/* Set the include chain for "" to QUOTE, for <> to BRACKET.  If
   QUOTE_IGNORES_SOURCE_DIR, then "" includes do not look in the
   directory of the including file.
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   If BRACKET does not lie in the QUOTE chain, it is set to QUOTE.  */
void
cpp_set_include_chains (cpp_reader *pfile, cpp_dir *quote, cpp_dir *bracket,
			int quote_ignores_source_dir)
1544
{
1545 1546 1547
  pfile->quote_include = quote;
  pfile->bracket_include = quote;
  pfile->quote_ignores_source_dir = quote_ignores_source_dir;
1548

1549
  for (; quote; quote = quote->next)
1550
    {
1551 1552 1553 1554
      quote->name_map = NULL;
      quote->len = strlen (quote->name);
      if (quote == bracket)
	pfile->bracket_include = bracket;
1555
    }
1556 1557
}

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/* Append the file name to the directory to create the path, but don't
   turn / into // or // into ///; // may be a namespace escape.  */
static char *
append_file_to_dir (const char *fname, cpp_dir *dir)
{
  size_t dlen, flen;
  char *path;

  dlen = dir->len;
  flen = strlen (fname);
1568
  path = XNEWVEC (char, dlen + 1 + flen + 1);
1569
  memcpy (path, dir->name, dlen);
1570
  if (dlen && !IS_DIR_SEPARATOR (path[dlen - 1]))
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    path[dlen++] = '/';
  memcpy (&path[dlen], fname, flen + 1);

  return path;
}
1576 1577

/* Read a space delimited string of unlimited length from a stdio
1578
   file F.  */
1579
static char *
1580
read_filename_string (int ch, FILE *f)
1581 1582 1583 1584 1585
{
  char *alloc, *set;
  int len;

  len = 20;
1586
  set = alloc = XNEWVEC (char, len + 1);
1587
  if (! is_space (ch))
1588 1589
    {
      *set++ = ch;
1590
      while ((ch = getc (f)) != EOF && ! is_space (ch))
1591 1592 1593 1594
	{
	  if (set - alloc == len)
	    {
	      len *= 2;
1595
	      alloc = XRESIZEVEC (char, alloc, len + 1);
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	      set = alloc + len / 2;
	    }
	  *set++ = ch;
	}
    }
  *set = '\0';
  ungetc (ch, f);
  return alloc;
}

1606 1607 1608
/* Read the file name map file for DIR.  */
static void
read_name_map (cpp_dir *dir)
1609
{
1610
  static const char FILE_NAME_MAP_FILE[] = "header.gcc";
1611 1612
  char *name;
  FILE *f;
1613 1614 1615
  size_t len, count = 0, room = 9;

  len = dir->len;
1616
  name = (char *) alloca (len + sizeof (FILE_NAME_MAP_FILE) + 1);
1617
  memcpy (name, dir->name, len);
1618
  if (len && !IS_DIR_SEPARATOR (name[len - 1]))
1619 1620
    name[len++] = '/';
  strcpy (name + len, FILE_NAME_MAP_FILE);
1621
  f = fopen (name, "r");
1622

1623
  dir->name_map = XNEWVEC (const char *, room);
1624

1625 1626
  /* Silently return NULL if we cannot open.  */
  if (f)
1627 1628 1629 1630 1631
    {
      int ch;

      while ((ch = getc (f)) != EOF)
	{
1632
	  char *to;
1633

1634
	  if (is_space (ch))
1635
	    continue;
1636 1637 1638 1639

	  if (count + 2 > room)
	    {
	      room += 8;
1640
	      dir->name_map = XRESIZEVEC (const char *, dir->name_map, room);
1641 1642 1643
	    }

	  dir->name_map[count] = read_filename_string (ch, f);
1644
	  while ((ch = getc (f)) != EOF && is_hspace (ch))
1645 1646
	    ;

1647
	  to = read_filename_string (ch, f);
1648
	  if (IS_ABSOLUTE_PATH (to))
1649
	    dir->name_map[count + 1] = to;
1650 1651
	  else
	    {
1652
	      dir->name_map[count + 1] = append_file_to_dir (to, dir);
1653
	      free (to);
1654
	    }
1655

1656
	  count += 2;
1657 1658 1659 1660
	  while ((ch = getc (f)) != '\n')
	    if (ch == EOF)
	      break;
	}
1661

1662 1663
      fclose (f);
    }
1664

1665 1666
  /* Terminate the list of maps.  */
  dir->name_map[count] = NULL;
1667
}
1668

1669 1670 1671
/* Remap a FILE's name based on the file_name_map, if any, for
   FILE->dir.  If the file name has any directory separators,
   recursively check those directories too.  */
1672
static char *
1673
remap_filename (cpp_reader *pfile, _cpp_file *file)
1674
{
1675
  const char *fname, *p;
1676
  char *new_dir, *p3;
1677 1678
  cpp_dir *dir;
  size_t index, len;
1679

1680 1681
  dir = file->dir;
  fname = file->name;
1682

1683 1684 1685 1686
  for (;;)
    {
      if (!dir->name_map)
	read_name_map (dir);
1687

1688
      for (index = 0; dir->name_map[index]; index += 2)
1689
	if (!filename_cmp (dir->name_map[index], fname))
1690
	    return xstrdup (dir->name_map[index + 1]);
1691 1692
      if (IS_ABSOLUTE_PATH (fname))
	return NULL;
1693
      p = strchr (fname, '/');
1694 1695 1696 1697 1698 1699 1700
#ifdef HAVE_DOS_BASED_FILE_SYSTEM
      {
	char *p2 = strchr (fname, '\\');
	if (!p || (p > p2))
	  p = p2;
      }
#endif
1701 1702
      if (!p || p == fname)
	return NULL;
1703

1704
      len = dir->len + (p - fname + 1);
1705 1706
      new_dir = XNEWVEC (char, len + 2);
      p3 = new_dir + dir->len;
1707
      memcpy (new_dir, dir->name, dir->len);
1708 1709 1710 1711 1712 1713
      if (dir->len && !IS_DIR_SEPARATOR (dir->name[dir->len - 1]))
	{
	  *p3++ = '/';
	  len++;
	}
      memcpy (p3, fname, p - fname + 1);
1714
      new_dir[len] = '\0';
1715

1716 1717
      dir = make_cpp_dir (pfile, new_dir, dir->sysp);
      fname = p + 1;
1718 1719
    }
}
1720

1721 1722 1723
/* Returns true if PCHNAME is a valid PCH file for FILE.  */
static bool
validate_pch (cpp_reader *pfile, _cpp_file *file, const char *pchname)
1724
{
1725
  const char *saved_path = file->path;
1726
  bool valid = false;
1727

1728 1729
  file->path = pchname;
  if (open_file (file))
1730
    {
1731
      valid = 1 & pfile->cb.valid_pch (pfile, pchname, file->fd);
1732

1733
      if (!valid)
1734
	{
1735 1736
	  close (file->fd);
	  file->fd = -1;
1737 1738
	}

1739
      if (CPP_OPTION (pfile, print_include_names))
1740
	{
1741
	  unsigned int i;
Per Bothner committed
1742
	  for (i = 1; i < pfile->line_table->depth; i++)
1743 1744
	    putc ('.', stderr);
	  fprintf (stderr, "%c %s\n",
1745
		   valid ? '!' : 'x', pchname);
1746 1747 1748
	}
    }

1749
  file->path = saved_path;
1750
  return valid;
1751
}
1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762

/* Get the path associated with the _cpp_file F.  The path includes
   the base name from the include directive and the directory it was
   found in via the search path.  */

const char *
cpp_get_path (struct _cpp_file *f)
{
  return f->path;
}

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/* Get the directory associated with the _cpp_file F.  */

cpp_dir *
cpp_get_dir (struct _cpp_file *f)
{
  return f->dir;
}

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/* Get the cpp_buffer currently associated with the cpp_reader
   PFILE.  */

cpp_buffer *
cpp_get_buffer (cpp_reader *pfile)
{
  return pfile->buffer;
}

/* Get the _cpp_file associated with the cpp_buffer B.  */

_cpp_file *
cpp_get_file (cpp_buffer *b)
{
  return b->file;
}

/* Get the previous cpp_buffer given a cpp_buffer B.  The previous
   buffer is the buffer that included the given buffer.  */

cpp_buffer *
cpp_get_prev (cpp_buffer *b)
{
  return b->prev;
}
Geoffrey Keating committed
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1797
/* This data structure holds the list of header files that were seen
Geoffrey Keating committed
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   while the PCH was being built.  The 'entries' field is kept sorted
   in memcmp() order; yes, this means that on little-endian systems,
   it's sorted initially by the least-significant byte of 'size', but
   that's OK.  The code does rely on having entries with the same size
   next to each other.  */

1804 1805 1806 1807 1808 1809 1810 1811 1812 1813
struct pchf_entry {
  /* The size of this file.  This is used to save running a MD5 checksum
     if the sizes don't match.  */
  off_t size;
  /* The MD5 checksum of this file.  */
  unsigned char sum[16];
  /* Is this file to be included only once?  */
  bool once_only;
};

Geoffrey Keating committed
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struct pchf_data {
  /* Number of pchf_entry structures.  */
  size_t count;

  /* Are there any values with once_only set?
     This is used as an optimisation, it means we don't have to search
     the structure if we're processing a regular #include.  */
  bool have_once_only;
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1823
  struct pchf_entry entries[1];
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};

static struct pchf_data *pchf;

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/* A qsort ordering function for pchf_entry structures.  */

static int
pchf_save_compare (const void *e1, const void *e2)
Geoffrey Keating committed
1832
{
1833 1834
  return memcmp (e1, e2, sizeof (struct pchf_entry));
}
Geoffrey Keating committed
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1836
/* Create and write to F a pchf_data structure.  */
Geoffrey Keating committed
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1838 1839
bool
_cpp_save_file_entries (cpp_reader *pfile, FILE *fp)
Geoffrey Keating committed
1840
{
1841 1842 1843 1844
  size_t count = 0;
  struct pchf_data *result;
  size_t result_size;
  _cpp_file *f;
1845
  bool ret;
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  for (f = pfile->all_files; f; f = f->next_file)
    ++count;

  result_size = (sizeof (struct pchf_data)
		 + sizeof (struct pchf_entry) * (count - 1));
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  result = XCNEWVAR (struct pchf_data, result_size);
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  result->count = 0;
  result->have_once_only = false;

  for (f = pfile->all_files; f; f = f->next_file)
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    {
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      size_t count;
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      /* This should probably never happen, since if a read error occurred
	 the PCH file shouldn't be written...  */
      if (f->dont_read || f->err_no)
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	continue;

      if (f->stack_count == 0)
	continue;
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      count = result->count++;

      result->entries[count].once_only = f->once_only;
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      /* |= is avoided in the next line because of an HP C compiler bug */
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      result->have_once_only = result->have_once_only | f->once_only;
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      if (f->buffer_valid)
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	md5_buffer ((const char *)f->buffer,
		    f->st.st_size, result->entries[count].sum);
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      else
	{
	  FILE *ff;
	  int oldfd = f->fd;

	  if (!open_file (f))
	    {
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	      open_file_failed (pfile, f, 0, 0);
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	      free (result);
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	      return false;
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	    }
	  ff = fdopen (f->fd, "rb");
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	  md5_stream (ff, result->entries[count].sum);
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	  fclose (ff);
	  f->fd = oldfd;
	}
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      result->entries[count].size = f->st.st_size;
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    }

  result_size = (sizeof (struct pchf_data)
                 + sizeof (struct pchf_entry) * (result->count - 1));
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  qsort (result->entries, result->count, sizeof (struct pchf_entry),
	 pchf_save_compare);

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  ret = fwrite (result, result_size, 1, fp) == 1;
  free (result);
  return ret;
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}

/* Read the pchf_data structure from F.  */

bool
_cpp_read_file_entries (cpp_reader *pfile ATTRIBUTE_UNUSED, FILE *f)
{
  struct pchf_data d;
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  if (fread (&d, sizeof (struct pchf_data) - sizeof (struct pchf_entry), 1, f)
       != 1)
    return false;
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  pchf = XNEWVAR (struct pchf_data, sizeof (struct pchf_data)
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		  + sizeof (struct pchf_entry) * (d.count - 1));
  memcpy (pchf, &d, sizeof (struct pchf_data) - sizeof (struct pchf_entry));
  if (fread (pchf->entries, sizeof (struct pchf_entry), d.count, f)
      != d.count)
    return false;
  return true;
}

/* The parameters for pchf_compare.  */

struct pchf_compare_data
{
  /* The size of the file we're looking for.  */
  off_t size;

  /* The MD5 checksum of the file, if it's been computed.  */
  unsigned char sum[16];

  /* Is SUM valid?  */
  bool sum_computed;

  /* Do we need to worry about entries that don't have ONCE_ONLY set?  */
  bool check_included;
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  /* The file that we're searching for.  */
  _cpp_file *f;
};

/* bsearch comparison function; look for D_P in E_P.  */

static int
pchf_compare (const void *d_p, const void *e_p)
{
  const struct pchf_entry *e = (const struct pchf_entry *)e_p;
  struct pchf_compare_data *d = (struct pchf_compare_data *)d_p;
  int result;
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  result = memcmp (&d->size, &e->size, sizeof (off_t));
  if (result != 0)
    return result;
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  if (! d->sum_computed)
    {
      _cpp_file *const f = d->f;
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      md5_buffer ((const char *)f->buffer, f->st.st_size, d->sum);
      d->sum_computed = true;
    }

  result = memcmp (d->sum, e->sum, 16);
  if (result != 0)
    return result;

  if (d->check_included || e->once_only)
    return 0;
  else
    return 1;
}

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/* Check that F is not in a list read from a PCH file (if any).
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   Assumes that f->buffer_valid is true.  Return TRUE if the file
   should not be read.  */

static bool
check_file_against_entries (cpp_reader *pfile ATTRIBUTE_UNUSED,
			    _cpp_file *f,
			    bool check_included)
{
  struct pchf_compare_data d;
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  if (pchf == NULL
      || (! check_included && ! pchf->have_once_only))
    return false;

  d.size = f->st.st_size;
  d.sum_computed = false;
  d.f = f;
  d.check_included = check_included;
  return bsearch (&d, pchf->entries, pchf->count, sizeof (struct pchf_entry),
		  pchf_compare) != NULL;
}
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/* Return true if the file FNAME is found in the appropriate include file path
   as indicated by ANGLE_BRACKETS.  */

bool
_cpp_has_header (cpp_reader *pfile, const char *fname, int angle_brackets,
		 enum include_type type)
{
  cpp_dir *start_dir = search_path_head (pfile, fname, angle_brackets, type);
  _cpp_file *file = _cpp_find_file (pfile, fname, start_dir,
				    /*fake=*/false, angle_brackets,
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				    /*implicit_preinclude=*/false, 0);
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  return file->err_no != ENOENT;
}