eh_globals.cc revision 97403 
1// -*- C++ -*- Manage the thread-local exception globals.
2// Copyright (C) 2001 Free Software Foundation, Inc.
3//
4// This file is part of GNU CC.
5//
6// GNU CC is free software; you can redistribute it and/or modify
7// it under the terms of the GNU General Public License as published by
8// the Free Software Foundation; either version 2, or (at your option)
9// any later version.
10//
11// GNU CC is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14// GNU General Public License for more details.
15//
16// You should have received a copy of the GNU General Public License
17// along with GNU CC; see the file COPYING.  If not, write to
18// the Free Software Foundation, 59 Temple Place - Suite 330,
19// Boston, MA 02111-1307, USA.
20
21// As a special exception, you may use this file as part of a free software
22// library without restriction.  Specifically, if other files instantiate
23// templates or use macros or inline functions from this file, or you compile
24// this file and link it with other files to produce an executable, this
25// file does not by itself cause the resulting executable to be covered by
26// the GNU General Public License.  This exception does not however
27// invalidate any other reasons why the executable file might be covered by
28// the GNU General Public License.
29
30
31#include <exception>
32#include <cstdlib>
33#include "unwind-cxx.h"
34#include "bits/c++config.h"
35#include "bits/gthr.h"
36
37using namespace __cxxabiv1;
38
39
40// Single-threaded fallback buffer.
41static __cxa_eh_globals globals_static;
42
43#if __GTHREADS
44static __gthread_key_t globals_key;
45static int use_thread_key = -1;
46
47static void
48get_globals_dtor (void *ptr)
49{
50  __gthread_key_dtor (globals_key, ptr);
51  if (ptr)
52    std::free (ptr);
53}
54
55static void
56get_globals_init ()
57{
58  use_thread_key =
59    (__gthread_key_create (&globals_key, get_globals_dtor) == 0);
60}
61
62static void
63get_globals_init_once ()
64{
65  static __gthread_once_t once = __GTHREAD_ONCE_INIT;
66  if (__gthread_once (&once, get_globals_init) != 0
67      || use_thread_key < 0)
68    use_thread_key = 0;
69}
70#endif
71
72extern "C" __cxa_eh_globals *
73__cxa_get_globals_fast ()
74{
75#if __GTHREADS
76  if (use_thread_key)
77    return (__cxa_eh_globals *) __gthread_getspecific (globals_key);
78  else
79    return &globals_static;
80#else
81  return &globals_static;
82#endif
83}
84
85extern "C" __cxa_eh_globals *
86__cxa_get_globals ()
87{
88#if __GTHREADS
89  __cxa_eh_globals *g;
90
91  if (use_thread_key == 0)
92    return &globals_static;
93
94  if (use_thread_key < 0)
95    {
96      get_globals_init_once ();
97
98      // Make sure use_thread_key got initialized.
99      if (use_thread_key == 0)
100	return &globals_static;
101    }
102
103  g = (__cxa_eh_globals *) __gthread_getspecific (globals_key);
104  if (! g)
105    {
106      if ((g = (__cxa_eh_globals *)
107	   std::malloc (sizeof (__cxa_eh_globals))) == 0
108	  || __gthread_setspecific (globals_key, (void *) g) != 0)
109        std::terminate ();
110      g->caughtExceptions = 0;
111      g->uncaughtExceptions = 0;
112    }
113
114  return g;
115#else
116  return &globals_static;
117#endif
118}
119