gcc/config/host-hpux.c

   1 /* HP-UX host-specific hook definitions.
   2    Copyright (C) 2004, 2005, 2007 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 <sys/mman.h>
  24 #include <unistd.h>
  25 #include "hosthooks.h"
  26 #include "hosthooks-def.h"
  27
  28 #ifndef MAP_FAILED
  29 #define MAP_FAILED (void *)-1L
  30 #endif
  31
  32 static void *hpux_gt_pch_get_address (size_t, int);
  33 static int hpux_gt_pch_use_address (void *, size_t, int, size_t);
  34
  35 #undef HOST_HOOKS_GT_PCH_GET_ADDRESS
  36 #define HOST_HOOKS_GT_PCH_GET_ADDRESS hpux_gt_pch_get_address
  37 #undef HOST_HOOKS_GT_PCH_USE_ADDRESS
  38 #define HOST_HOOKS_GT_PCH_USE_ADDRESS hpux_gt_pch_use_address
  39
  40 /* For various ports, try to guess a fixed spot in the vm space
  41    that's probably free.  */
  42 #if (defined(__hppa__) || defined(__ia64__)) && defined(__LP64__)
  43 # define TRY_EMPTY_VM_SPACE     0x8000000000000000
  44 #elif defined(__hppa__) || defined(__ia64__)
  45 # define TRY_EMPTY_VM_SPACE     0x60000000
  46 #else
  47 # define TRY_EMPTY_VM_SPACE     0
  48 #endif
  49
  50 /* Determine a location where we might be able to reliably allocate
  51    SIZE bytes.  FD is the PCH file, though we should return with the
  52    file unmapped.  */
  53
  54 static void *
  55 hpux_gt_pch_get_address (size_t size, int fd)
  56 {
  57   void *addr;
  58
  59   addr = mmap ((void *)TRY_EMPTY_VM_SPACE, size, PROT_READ | PROT_WRITE,
  60                MAP_PRIVATE, fd, 0);
  61
  62   /* If we failed the map, that means there's *no* free space.  */
  63   if (addr == (void *) MAP_FAILED)
  64     return NULL;
  65   /* Unmap the area before returning.  */
  66   munmap (addr, size);
  67
  68   return addr;
  69 }
  70
  71 /* Map SIZE bytes of FD+OFFSET at BASE.  Return 1 if we succeeded at
  72    mapping the data at BASE, -1 if we couldn't.
  73
  74    It's not possibly to reliably mmap a file using MAP_PRIVATE to
  75    a specific START address on either hpux or linux.  First we see
  76    if mmap with MAP_PRIVATE works.  If it does, we are off to the
  77    races.  If it doesn't, we try an anonymous private mmap since the
  78    kernel is more likely to honor the BASE address in anonymous maps.
  79    We then copy the data to the anonymous private map.  This assumes
  80    of course that we don't need to change the data in the PCH file
  81    after it is created.
  82
  83    This approach obviously causes a performance penalty but there is
  84    little else we can do given the current PCH implementation.  */
  85
  86 static int
  87 hpux_gt_pch_use_address (void *base, size_t size, int fd, size_t offset)
  88 {
  89   void *addr;
  90
  91   /* We're called with size == 0 if we're not planning to load a PCH
  92      file at all.  This allows the hook to free any static space that
  93      we might have allocated at link time.  */
  94   if (size == 0)
  95     return -1;
  96
  97   /* Try to map the file with MAP_PRIVATE.  */
  98   addr = mmap (base, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, offset);
  99
 100   if (addr == base)
 101     return 1;
 102
 103   if (addr != (void *) MAP_FAILED)
 104     munmap (addr, size);
 105
 106   /* Try to make an anonymous private mmap at the desired location.  */
 107   addr = mmap (base, size, PROT_READ | PROT_WRITE,
 108                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 109
 110   if (addr != base)
 111     {
 112       if (addr != (void *) MAP_FAILED)
 113         munmap (addr, size);
 114       return -1;
 115     }
 116
 117   if (lseek (fd, offset, SEEK_SET) == (off_t)-1)
 118     return -1;
 119
 120   while (size)
 121     {
 122       ssize_t nbytes;
 123
 124       nbytes = read (fd, base, MIN (size, SSIZE_MAX));
 125       if (nbytes <= 0)
 126         return -1;
 127       base = (char *) base + nbytes;
 128       size -= nbytes;
 129     }
 130
 131   return 1;
 132 }
 133
 134 \f
 135 const struct host_hooks host_hooks = HOST_HOOKS_INITIALIZER;