gcc/config/host-darwin.c

   1 /* Darwin host-specific hook definitions.
   2    Copyright (C) 2003-2018 Free Software Foundation, Inc.
   3
   4    This file is part of GCC.
   5
   6    GCC is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published
   8    by the Free Software Foundation; either version 3, or (at your
   9    option) any later version.
  10
  11    GCC is distributed in the hope that it will be useful, but WITHOUT
  12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  14    License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GCC; see the file COPYING3.  If not see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "diagnostic-core.h"
  24 #include "config/host-darwin.h"
  25
  26 /* Yes, this is really supposed to work.  */
  27 static char pch_address_space[1024*1024*1024] __attribute__((aligned (4096)));
  28
  29 /* Return the address of the PCH address space, if the PCH will fit in it.  */
  30
  31 void *
  32 darwin_gt_pch_get_address (size_t sz, int fd ATTRIBUTE_UNUSED)
  33 {
  34   if (sz <= sizeof (pch_address_space))
  35     return pch_address_space;
  36   else
  37     return NULL;
  38 }
  39
  40 /* Check ADDR and SZ for validity, and deallocate (using munmap) that part of
  41    pch_address_space beyond SZ.  */
  42
  43 int
  44 darwin_gt_pch_use_address (void *addr, size_t sz, int fd, size_t off)
  45 {
  46   const size_t pagesize = getpagesize();
  47   void *mmap_result;
  48   int ret;
  49
  50   gcc_assert ((size_t)pch_address_space % pagesize == 0
  51               && sizeof (pch_address_space) % pagesize == 0);
  52
  53   ret = (addr == pch_address_space && sz <= sizeof (pch_address_space));
  54   if (! ret)
  55     sz = 0;
  56
  57   /* Round the size to a whole page size.  Normally this is a no-op.  */
  58   sz = (sz + pagesize - 1) / pagesize * pagesize;
  59
  60   if (munmap (pch_address_space + sz, sizeof (pch_address_space) - sz) != 0)
  61     fatal_error (input_location, "couldn%'t unmap pch_address_space: %m");
  62
  63   if (ret)
  64     {
  65       mmap_result = mmap (addr, sz,
  66                           PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_FIXED,
  67                           fd, off);
  68
  69       /* The file might not be mmap-able.  */
  70       ret = mmap_result != (void *) MAP_FAILED;
  71
  72       /* Sanity check for broken MAP_FIXED.  */
  73       gcc_assert (!ret || mmap_result == addr);
  74     }
  75
  76   return ret;
  77 }