eh_globals.cc revision 146897 
1// -*- C++ -*- Manage the thread-local exception globals.
2// Copyright (C) 2001, 2004 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
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// GCC 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 GCC; 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  if (ptr)
51    {
52      __cxa_exception *exn, *next;
53      exn = ((__cxa_eh_globals *) ptr)->caughtExceptions;
54      while (exn)
55	{
56	  next = exn->nextException;
57	  _Unwind_DeleteException (&exn->unwindHeader);
58	  exn = next;
59	}
60      std::free (ptr);
61    }
62}
63
64static void
65get_globals_init ()
66{
67  use_thread_key =
68    (__gthread_key_create (&globals_key, get_globals_dtor) == 0);
69}
70
71static void
72get_globals_init_once ()
73{
74  static __gthread_once_t once = __GTHREAD_ONCE_INIT;
75  if (__gthread_once (&once, get_globals_init) != 0
76      || use_thread_key < 0)
77    use_thread_key = 0;
78}
79#endif
80
81extern "C" __cxa_eh_globals *
82__cxa_get_globals_fast () throw()
83{
84#if __GTHREADS
85  if (use_thread_key)
86    return (__cxa_eh_globals *) __gthread_getspecific (globals_key);
87  else
88    return &globals_static;
89#else
90  return &globals_static;
91#endif
92}
93
94extern "C" __cxa_eh_globals *
95__cxa_get_globals () throw()
96{
97#if __GTHREADS
98  __cxa_eh_globals *g;
99
100  if (use_thread_key == 0)
101    return &globals_static;
102
103  if (use_thread_key < 0)
104    {
105      get_globals_init_once ();
106
107      // Make sure use_thread_key got initialized.
108      if (use_thread_key == 0)
109	return &globals_static;
110    }
111
112  g = (__cxa_eh_globals *) __gthread_getspecific (globals_key);
113  if (! g)
114    {
115      if ((g = (__cxa_eh_globals *)
116	   std::malloc (sizeof (__cxa_eh_globals))) == 0
117	  || __gthread_setspecific (globals_key, (void *) g) != 0)
118        std::terminate ();
119      g->caughtExceptions = 0;
120      g->uncaughtExceptions = 0;
121    }
122
123  return g;
124#else
125  return &globals_static;
126#endif
127}
128