gcc/config/host-hpux.c

   1 /* HP-UX host-specific hook definitions.
   2    Copyright (C) 2004, 2005 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 2, 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 COPYING.  If not, write to the
  18    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include <sys/mman.h>
  25 #include <unistd.h>
  26 #include "hosthooks.h"
  27 #include "hosthooks-def.h"
  28
  29 #ifndef MAP_FAILED
  30 #define MAP_FAILED (void *)-1L
  31 #endif
  32
  33 static void *hpux_gt_pch_get_address (size_t, int);
  34 static int hpux_gt_pch_use_address (void *, size_t, int, size_t);
  35
  36 #undef HOST_HOOKS_GT_PCH_GET_ADDRESS
  37 #define HOST_HOOKS_GT_PCH_GET_ADDRESS hpux_gt_pch_get_address
  38 #undef HOST_HOOKS_GT_PCH_USE_ADDRESS
  39 #define HOST_HOOKS_GT_PCH_USE_ADDRESS hpux_gt_pch_use_address
  40
  41 /* For various ports, try to guess a fixed spot in the vm space
  42    that's probably free.  */
  43 #if (defined(__hppa__) || defined(__ia64__)) && defined(__LP64__)
  44 # define TRY_EMPTY_VM_SPACE     0x8000000000000000
  45 #elif defined(__hppa__) || defined(__ia64__)
  46 # define TRY_EMPTY_VM_SPACE     0x60000000
  47 #else
  48 # define TRY_EMPTY_VM_SPACE     0
  49 #endif
  50
  51 /* Determine a location where we might be able to reliably allocate
  52    SIZE bytes.  FD is the PCH file, though we should return with the
  53    file unmapped.  */
  54
  55 static void *
  56 hpux_gt_pch_get_address (size_t size, int fd)
  57 {
  58   void *addr;
  59
  60   addr = mmap ((void *)TRY_EMPTY_VM_SPACE, size, PROT_READ | PROT_WRITE,
  61                MAP_PRIVATE, fd, 0);
  62
  63   /* If we failed the map, that means there's *no* free space.  */
  64   if (addr == (void *) MAP_FAILED)
  65     return NULL;
  66   /* Unmap the area before returning.  */
  67   munmap (addr, size);
  68
  69   return addr;
  70 }
  71
  72 /* Map SIZE bytes of FD+OFFSET at BASE.  Return 1 if we succeeded at
  73    mapping the data at BASE, -1 if we couldn't.
  74
  75    It's not possibly to reliably mmap a file using MAP_PRIVATE to
  76    a specific START address on either hpux or linux.  First we see
  77    if mmap with MAP_PRIVATE works.  If it does, we are off to the
  78    races.  If it doesn't, we try an anonymous private mmap since the
  79    kernel is more likely to honor the BASE address in anonymous maps.
  80    We then copy the data to the anonymous private map.  This assumes
  81    of course that we don't need to change the data in the PCH file
  82    after it is created.
  83
  84    This approach obviously causes a performance penalty but there is
  85    little else we can do given the current PCH implementation.  */
  86
  87 static int
  88 hpux_gt_pch_use_address (void *base, size_t size, int fd, size_t offset)
  89 {
  90   void *addr;
  91
  92   /* We're called with size == 0 if we're not planning to load a PCH
  93      file at all.  This allows the hook to free any static space that
  94      we might have allocated at link time.  */
  95   if (size == 0)
  96     return -1;
  97
  98   /* Try to map the file with MAP_PRIVATE.  */
  99   addr = mmap (base, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, offset);
 100
 101   if (addr == base)
 102     return 1;
 103
 104   if (addr != (void *) MAP_FAILED)
 105     munmap (addr, size);
 106
 107   /* Try to make an anonymous private mmap at the desired location.  */
 108   addr = mmap (base, size, PROT_READ | PROT_WRITE,
 109                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 110
 111   if (addr != base)
 112     {
 113       if (addr != (void *) MAP_FAILED)
 114         munmap (addr, size);
 115       return -1;
 116     }
 117
 118   if (lseek (fd, offset, SEEK_SET) == (off_t)-1)
 119     return -1;
 120
 121   while (size)
 122     {
 123       ssize_t nbytes;
 124
 125       nbytes = read (fd, base, MIN (size, SSIZE_MAX));
 126       if (nbytes <= 0)
 127         return -1;
 128       base = (char *) base + nbytes;
 129       size -= nbytes;
 130     }
 131
 132   return 1;
 133 }
 134
 135 \f
 136 const struct host_hooks host_hooks = HOST_HOOKS_INITIALIZER;