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/* Darwin host-specific hook definitions.

   Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.

   This file is part of GCC.

   GCC is free software; you can redistribute it and/or modify it

   under the terms of the GNU General Public License as published

   by the Free Software Foundation; either version 2, or (at your

   option) any later version.

   GCC 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

   along with GCC; see the file COPYING.  If not, write to the

   Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,

   MA 02110-1301, USA.  */

#include "config.h"

#include "system.h"

#include "coretypes.h"

#include <sys/mman.h>

#include "toplev.h"

#include "config/host-darwin.h"

/* Yes, this is really supposed to work.  */

static char pch_address_space[1024*1024*1024] __attribute__((aligned (4096)));

/* Return the address of the PCH address space, if the PCH will fit in it.  */

void *

darwin_gt_pch_get_address (size_t sz, int fd ATTRIBUTE_UNUSED)

{

  if (sz <= sizeof (pch_address_space))

    return pch_address_space;

  else

    return NULL;

}

/* Check ADDR and SZ for validity, and deallocate (using munmap) that part of

   pch_address_space beyond SZ.  */

int

darwin_gt_pch_use_address (void *addr, size_t sz, int fd, size_t off)

{

  const size_t pagesize = getpagesize();

  void *mmap_result;

  int ret;

  gcc_assert ((size_t)pch_address_space % pagesize == 0

              && sizeof (pch_address_space) % pagesize == 0);

  ret = (addr == pch_address_space && sz <= sizeof (pch_address_space));

  if (! ret)

    sz = 0;

  /* Round the size to a whole page size.  Normally this is a no-op.  */

  sz = (sz + pagesize - 1) / pagesize * pagesize;

  if (munmap (pch_address_space + sz, sizeof (pch_address_space) - sz) != 0)

    fatal_error ("couldn't unmap pch_address_space: %m");

  if (ret)

    {

      mmap_result = mmap (addr, sz,

                          PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_FIXED,

                          fd, off);

      /* The file might not be mmap-able.  */

      ret = mmap_result != (void *) MAP_FAILED;

      /* Sanity check for broken MAP_FIXED.  */

      gcc_assert (!ret || mmap_result == addr);

    }

  return ret;

}