gcc/emutls.c

   1 /* TLS emulation.
   2    Copyright (C) 2006 Free Software Foundation, Inc.
   3    Contributed by Jakub Jelinek <jakub@redhat.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 In addition to the permissions in the GNU General Public License, the
  13 Free Software Foundation gives you unlimited permission to link the
  14 compiled version of this file into combinations with other programs,
  15 and to distribute those combinations without any restriction coming
  16 from the use of this file.  (The General Public License restrictions
  17 do apply in other respects; for example, they cover modification of
  18 the file, and distribution when not linked into a combine
  19 executable.)
  20
  21 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  22 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  23 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  24 for more details.
  25
  26 You should have received a copy of the GNU General Public License
  27 along with GCC; see the file COPYING.  If not, write to the Free
  28 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  29 02110-1301, USA.  */
  30
  31 #include "tconfig.h"
  32 #include "tsystem.h"
  33 #include "coretypes.h"
  34 #include "tm.h"
  35 #include "gthr.h"
  36
  37 typedef unsigned int word __attribute__((mode(word)));
  38 typedef unsigned int pointer __attribute__((mode(pointer)));
  39
  40 struct __emutls_object
  41 {
  42   word size;
  43   word align;
  44   union {
  45     pointer offset;
  46     void *ptr;
  47   } loc;
  48   void *templ;
  49 };
  50
  51 #ifdef __GTHREADS
  52 #ifdef __GTHREAD_MUTEX_INIT
  53 static __gthread_mutex_t emutls_mutex = __GTHREAD_MUTEX_INIT;
  54 #else
  55 static __gthread_mutex_t emutls_mutex;
  56 #endif
  57 static __gthread_key_t emutls_key;
  58 static pointer emutls_size;
  59
  60 static void
  61 emutls_destroy (void *ptr)
  62 {
  63   void ***arr = (void ***) ptr;
  64   unsigned long int size = (unsigned long int) arr[0];
  65   ++arr;
  66   while (--size)
  67     {
  68       if (*arr)
  69         free ((*arr)[-1]);
  70       ++arr;
  71     }
  72   free (ptr);
  73 }
  74
  75 static void
  76 emutls_init (void)
  77 {
  78 #ifndef __GTHREAD_MUTEX_INIT
  79   __GTHREAD_MUTEX_INIT_FUNCTION (&emutls_mutex);
  80 #endif
  81   if (__gthread_key_create (&emutls_key, emutls_destroy) != 0)
  82     abort ();
  83 }
  84 #endif
  85
  86 static void *
  87 emutls_alloc (struct __emutls_object *obj)
  88 {
  89   void *ptr;
  90   void *ret;
  91
  92   /* We could use here posix_memalign if available and adjust
  93      emutls_destroy accordingly.  */
  94   if (obj->align <= sizeof (void *))
  95     {
  96       ptr = malloc (obj->size + sizeof (void *));
  97       if (ptr == NULL)
  98         abort ();
  99       ((void **) ptr)[0] = ptr;
 100       ret = ptr + sizeof (void *);
 101     }
 102   else
 103     {
 104       ptr = malloc (obj->size + sizeof (void *) + obj->align - 1);
 105       if (ptr == NULL)
 106         abort ();
 107       ret = (void *) (((pointer) (ptr + sizeof (void *) + obj->align - 1))
 108                       & ~(pointer)(obj->align - 1));
 109       ((void **) ret)[-1] = ptr;
 110     }
 111
 112   if (obj->templ)
 113     memcpy (ret, obj->templ, obj->size);
 114   else
 115     memset (ret, 0, obj->size);
 116
 117   return ret;
 118 }
 119
 120 void *
 121 __emutls_get_address (struct __emutls_object *obj)
 122 {
 123   if (! __gthread_active_p ())
 124     {
 125       if (__builtin_expect (obj->loc.ptr == NULL, 0))
 126         obj->loc.ptr = emutls_alloc (obj);
 127       return obj->loc.ptr;
 128     }
 129
 130 #ifndef __GTHREADS
 131   abort ();
 132 #else
 133   pointer offset;
 134
 135   if (__builtin_expect (obj->loc.offset == 0, 0))
 136     {
 137       static __gthread_once_t once = __GTHREAD_ONCE_INIT;
 138       __gthread_once (&once, emutls_init);
 139       __gthread_mutex_lock (&emutls_mutex);
 140       offset = ++emutls_size;
 141       obj->loc.offset = offset;
 142       __gthread_mutex_unlock (&emutls_mutex);
 143     }
 144   else
 145     offset = obj->loc.offset;
 146
 147   void **arr = (void **) __gthread_getspecific (emutls_key);
 148   if (__builtin_expect (arr == NULL, 0))
 149     {
 150       pointer size = offset + 32;
 151       arr = calloc (size, sizeof (void *));
 152       if (arr == NULL)
 153         abort ();
 154       arr[0] = (void *) size;
 155       __gthread_setspecific (emutls_key, (void *) arr);
 156     }
 157   else if (__builtin_expect (offset >= (pointer) arr[0], 0))
 158     {
 159       pointer orig_size = (pointer) arr[0];
 160       pointer size = orig_size * 2;
 161       if (offset >= size)
 162         size = offset + 32;
 163       arr = realloc (arr, size * sizeof (void *));
 164       if (arr == NULL)
 165         abort ();
 166       memset (arr + orig_size, 0, (size - orig_size) * sizeof (void *));
 167       __gthread_setspecific (emutls_key, (void *) arr);
 168     }
 169
 170   void *ret = arr[offset];
 171   if (__builtin_expect (ret == NULL, 0))
 172     {
 173       ret = emutls_alloc (obj);
 174       arr[offset] = ret;
 175     }
 176   return ret;
 177 #endif
 178 }
 179
 180 void
 181 __emutls_register_common (struct __emutls_object *obj,
 182                           word size, word align, void *templ)
 183 {
 184   if (obj->size < size)
 185     {
 186       obj->size = size;
 187       obj->templ = NULL;
 188     }
 189   if (obj->align < align)
 190     obj->align = align;
 191   if (templ && size == obj->size)
 192     obj->templ = templ;
 193 }