aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.9/libgcc/emutls.c
blob: cba9c3b03e6430374fd417fe315881e0c41aff71 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
/* TLS emulation.
   Copyright (C) 2006-2014 Free Software Foundation, Inc.
   Contributed by Jakub Jelinek <jakub@redhat.com>.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#include "tconfig.h"
#include "tsystem.h"
#include "coretypes.h"
#include "tm.h"
#include "libgcc_tm.h"
#include "gthr.h"

typedef unsigned int word __attribute__((mode(word)));
typedef unsigned int pointer __attribute__((mode(pointer)));

struct __emutls_object
{
  word size;
  word align;
  union {
    pointer offset;
    void *ptr;
  } loc;
  void *templ;
};

struct __emutls_array
{
  pointer size;
  void **data[];
};

void *__emutls_get_address (struct __emutls_object *);
void __emutls_register_common (struct __emutls_object *, word, word, void *);

#ifdef __GTHREADS
#ifdef __GTHREAD_MUTEX_INIT
static __gthread_mutex_t emutls_mutex = __GTHREAD_MUTEX_INIT;
#else
static __gthread_mutex_t emutls_mutex;
#endif
static __gthread_key_t emutls_key;
static int emutls_key_created = 0;
static pointer emutls_size;

static void
emutls_destroy (void *ptr)
{
  struct __emutls_array *arr = ptr;
  pointer size = arr->size;
  pointer i;

  for (i = 0; i < size; ++i)
    {
      if (arr->data[i])
	free (arr->data[i][-1]);
    }

  free (ptr);
}

static void
emutls_init (void)
{
#ifndef __GTHREAD_MUTEX_INIT
  __GTHREAD_MUTEX_INIT_FUNCTION (&emutls_mutex);
#endif
  if (__gthread_key_create (&emutls_key, emutls_destroy) != 0)
    abort ();
  emutls_key_created = 1;
}

__attribute__((destructor))
static void
unregister_emutls_key (void)
{
  if (emutls_key_created)
    __gthread_key_delete (emutls_key);
}
#endif

static void *
emutls_alloc (struct __emutls_object *obj)
{
  void *ptr;
  void *ret;

  /* We could use here posix_memalign if available and adjust
     emutls_destroy accordingly.  */
  if (obj->align <= sizeof (void *))
    {
      ptr = malloc (obj->size + sizeof (void *));
      if (ptr == NULL)
	abort ();
      ((void **) ptr)[0] = ptr;
      ret = ptr + sizeof (void *);
    }
  else
    {
      ptr = malloc (obj->size + sizeof (void *) + obj->align - 1);
      if (ptr == NULL)
	abort ();
      ret = (void *) (((pointer) (ptr + sizeof (void *) + obj->align - 1))
		      & ~(pointer)(obj->align - 1));
      ((void **) ret)[-1] = ptr;
    }

  if (obj->templ)
    memcpy (ret, obj->templ, obj->size);
  else
    memset (ret, 0, obj->size);

  return ret;
}

void *
__emutls_get_address (struct __emutls_object *obj)
{
  if (! __gthread_active_p ())
    {
      if (__builtin_expect (obj->loc.ptr == NULL, 0))
	obj->loc.ptr = emutls_alloc (obj);
      return obj->loc.ptr;
    }

#ifndef __GTHREADS
  abort ();
#else
  pointer offset = __atomic_load_n (&obj->loc.offset, __ATOMIC_ACQUIRE);

  if (__builtin_expect (offset == 0, 0))
    {
      static __gthread_once_t once = __GTHREAD_ONCE_INIT;
      __gthread_once (&once, emutls_init);
      __gthread_mutex_lock (&emutls_mutex);
      offset = obj->loc.offset;
      if (offset == 0)
	{
	  offset = ++emutls_size;
	  __atomic_store_n (&obj->loc.offset, offset, __ATOMIC_RELEASE);
	}
      __gthread_mutex_unlock (&emutls_mutex);
    }

  struct __emutls_array *arr = __gthread_getspecific (emutls_key);
  if (__builtin_expect (arr == NULL, 0))
    {
      pointer size = offset + 32;
      arr = calloc (size + 1, sizeof (void *));
      if (arr == NULL)
	abort ();
      arr->size = size;
      __gthread_setspecific (emutls_key, (void *) arr);
    }
  else if (__builtin_expect (offset > arr->size, 0))
    {
      pointer orig_size = arr->size;
      pointer size = orig_size * 2;
      if (offset > size)
	size = offset + 32;
      arr = realloc (arr, (size + 1) * sizeof (void *));
      if (arr == NULL)
	abort ();
      arr->size = size;
      memset (arr->data + orig_size, 0,
	      (size - orig_size) * sizeof (void *));
      __gthread_setspecific (emutls_key, (void *) arr);
    }

  void *ret = arr->data[offset - 1];
  if (__builtin_expect (ret == NULL, 0))
    {
      ret = emutls_alloc (obj);
      arr->data[offset - 1] = ret;
    }
  return ret;
#endif
}

void
__emutls_register_common (struct __emutls_object *obj,
			  word size, word align, void *templ)
{
  if (obj->size < size)
    {
      obj->size = size;
      obj->templ = NULL;
    }
  if (obj->align < align)
    obj->align = align;
  if (templ && size == obj->size)
    obj->templ = templ;
}