--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/config/host-darwin.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,78 @@
+/* Darwin host-specific hook definitions.
+   Copyright (C) 2003, 2004, 2005, 2007 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 3, 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 COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+#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;
+}