gcc/config/host-hpux.cc

   1 /* HP-UX host-specific hook definitions.
   2    Copyright (C) 2004-2024 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 static void *hpux_gt_pch_get_address (size_t, int);
  27 static int hpux_gt_pch_use_address (void *&, size_t, int, size_t);
  28
  29 #undef HOST_HOOKS_GT_PCH_GET_ADDRESS
  30 #define HOST_HOOKS_GT_PCH_GET_ADDRESS hpux_gt_pch_get_address
  31 #undef HOST_HOOKS_GT_PCH_USE_ADDRESS
  32 #define HOST_HOOKS_GT_PCH_USE_ADDRESS hpux_gt_pch_use_address
  33
  34 /* For various ports, try to guess a fixed spot in the vm space
  35    that's probably free.  */
  36 #if (defined(__hppa__) || defined(__ia64__)) && defined(__LP64__)
  37 # define TRY_EMPTY_VM_SPACE     0x8000000000000000
  38 #elif defined(__hppa__) || defined(__ia64__)
  39 # define TRY_EMPTY_VM_SPACE     0x60000000
  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 hpux_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    It's not possibly to reliably mmap a file using MAP_PRIVATE to
  69    a specific START address on either hpux or linux.  First we see
  70    if mmap with MAP_PRIVATE works.  If it does, we are off to the
  71    races.  If it doesn't, we try an anonymous private mmap since the
  72    kernel is more likely to honor the BASE address in anonymous maps.
  73    We then copy the data to the anonymous private map.  This assumes
  74    of course that we don't need to change the data in the PCH file
  75    after it is created.
  76
  77    This approach obviously causes a performance penalty but there is
  78    little else we can do given the current PCH implementation.  */
  79
  80 static int
  81 hpux_gt_pch_use_address (void *&base, size_t size, int fd, size_t offset)
  82 {
  83   void *addr;
  84
  85   /* We're called with size == 0 if we're not planning to load a PCH
  86      file at all.  This allows the hook to free any static space that
  87      we might have allocated at link time.  */
  88   if (size == 0)
  89     return -1;
  90
  91   /* Try to map the file with MAP_PRIVATE.  */
  92   addr = mmap (base, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, offset);
  93
  94   if (addr == base)
  95     return 1;
  96
  97   if (addr != (void *) MAP_FAILED)
  98     munmap (addr, size);
  99
 100   /* Try to make an anonymous private mmap at the desired location.  */
 101   addr = mmap (base, size, PROT_READ | PROT_WRITE,
 102                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 103
 104   if (addr != base)
 105     {
 106       if (addr != (void *) MAP_FAILED)
 107         munmap (addr, size);
 108       return -1;
 109     }
 110
 111   if (lseek (fd, offset, SEEK_SET) == (off_t)-1)
 112     return -1;
 113
 114   while (size)
 115     {
 116       ssize_t nbytes;
 117
 118       nbytes = read (fd, addr, MIN (size, SSIZE_MAX));
 119       if (nbytes <= 0)
 120         return -1;
 121       addr = (char *) addr + nbytes;
 122       size -= nbytes;
 123     }
 124
 125   return 1;
 126 }
 127
 128 \f
 129 const struct host_hooks host_hooks = HOST_HOOKS_INITIALIZER;