gcc/config/host-openbsd.c

   1 /* OpenBSD host-specific hook definitions.
   2    Copyright (C) 2004-2017 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 "hosthooks.h"
  24 #include "hosthooks-def.h"
  25
  26
  27 #undef HOST_HOOKS_GT_PCH_GET_ADDRESS
  28 #define HOST_HOOKS_GT_PCH_GET_ADDRESS openbsd_gt_pch_get_address
  29 #undef HOST_HOOKS_GT_PCH_USE_ADDRESS
  30 #define HOST_HOOKS_GT_PCH_USE_ADDRESS openbsd_gt_pch_use_address
  31
  32 /* For various ports, try to guess a fixed spot in the vm space
  33    that's probably free.  */
  34 #if defined(__amd64__)
  35 # define TRY_EMPTY_VM_SPACE     0x400000000000
  36 #elif defined(__hppa__)
  37 # define TRY_EMPTY_VM_SPACE     0xb0000000
  38 #elif defined(__i386__)
  39 # define TRY_EMPTY_VM_SPACE     0xb0000000
  40 #else
  41 # define TRY_EMPTY_VM_SPACE     0
  42 #endif
  43
  44 /* Determine a location where we might be able to reliably allocate
  45    SIZE bytes.  FD is the PCH file, though we should return with the
  46    file unmapped.  */
  47
  48 static void *
  49 openbsd_gt_pch_get_address (size_t size, int fd)
  50 {
  51   void *addr;
  52
  53   addr = mmap ((void *) TRY_EMPTY_VM_SPACE, size, PROT_READ | PROT_WRITE,
  54                MAP_PRIVATE, fd, 0);
  55
  56   /* If we failed the map, that means there's *no* free space.  */
  57   if (addr == (void *) MAP_FAILED)
  58     return NULL;
  59   /* Unmap the area before returning.  */
  60   munmap (addr, size);
  61
  62   return addr;
  63 }
  64
  65 /* Map SIZE bytes of FD+OFFSET at BASE.  Return 1 if we succeeded at
  66    mapping the data at BASE, -1 if we couldn't.  */
  67
  68 static int
  69 openbsd_gt_pch_use_address (void *base, size_t size, int fd, size_t offset)
  70 {
  71   void *addr;
  72
  73   /* We're called with size == 0 if we're not planning to load a PCH
  74      file at all.  This allows the hook to free any static space that
  75      we might have allocated at link time.  */
  76   if (size == 0)
  77     return -1;
  78
  79   addr = mmap (base, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, offset);
  80
  81   return addr == base ? 1 : -1;
  82 }
  83
  84 \f
  85 const struct host_hooks host_hooks = HOST_HOOKS_INITIALIZER;