eh_globals.cc Source File

00001 // -*- C++ -*- Manage the thread-local exception globals.
00002 // Copyright (C) 2001 Free Software Foundation, Inc.
00003 //
00004 // This file is part of GNU CC.
00005 //
00006 // GNU CC is free software; you can redistribute it and/or modify
00007 // it under the terms of the GNU General Public License as published by
00008 // the Free Software Foundation; either version 2, or (at your option)
00009 // any later version.
00010 //
00011 // GNU CC is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 //
00016 // You should have received a copy of the GNU General Public License
00017 // along with GNU CC; see the file COPYING.  If not, write to
00018 // the Free Software Foundation, 59 Temple Place - Suite 330,
00019 // Boston, MA 02111-1307, USA.
00020 
00021 // As a special exception, you may use this file as part of a free software
00022 // library without restriction.  Specifically, if other files instantiate
00023 // templates or use macros or inline functions from this file, or you compile
00024 // this file and link it with other files to produce an executable, this
00025 // file does not by itself cause the resulting executable to be covered by
00026 // the GNU General Public License.  This exception does not however
00027 // invalidate any other reasons why the executable file might be covered by
00028 // the GNU General Public License.
00029 
00030 
00031 #include <exception>
00032 #include <cstdlib>
00033 #include "unwind-cxx.h"
00034 #include "bits/c++config.h"
00035 #include "bits/gthr.h"
00036 
00037 using namespace __cxxabiv1;
00038 
00039 
00040 // Single-threaded fallback buffer.
00041 static __cxa_eh_globals globals_static;
00042 
00043 #if __GTHREADS
00044 static __gthread_key_t globals_key;
00045 static int use_thread_key = -1;
00046 
00047 static void
00048 get_globals_dtor (void *ptr)
00049 {
00050   __gthread_key_dtor (globals_key, ptr);
00051   if (ptr)
00052     std::free (ptr);
00053 }
00054 
00055 static void
00056 get_globals_init ()
00057 {
00058   use_thread_key =
00059     (__gthread_key_create (&globals_key, get_globals_dtor) == 0);
00060 }
00061 
00062 static void
00063 get_globals_init_once ()
00064 {
00065   static __gthread_once_t once = __GTHREAD_ONCE_INIT;
00066   if (__gthread_once (&once, get_globals_init) != 0
00067       || use_thread_key < 0)
00068     use_thread_key = 0;
00069 }
00070 #endif
00071 
00072 extern "C" __cxa_eh_globals *
00073 __cxa_get_globals_fast ()
00074 {
00075 #if __GTHREADS
00076   if (use_thread_key)
00077     return (__cxa_eh_globals *) __gthread_getspecific (globals_key);
00078   else
00079     return &globals_static;
00080 #else
00081   return &globals_static;
00082 #endif
00083 }
00084 
00085 extern "C" __cxa_eh_globals *
00086 __cxa_get_globals ()
00087 {
00088 #if __GTHREADS
00089   __cxa_eh_globals *g;
00090 
00091   if (use_thread_key == 0)
00092     return &globals_static;
00093 
00094   if (use_thread_key < 0)
00095     {
00096       get_globals_init_once ();
00097 
00098       // Make sure use_thread_key got initialized.
00099       if (use_thread_key == 0)
00100     return &globals_static;
00101     }
00102 
00103   g = (__cxa_eh_globals *) __gthread_getspecific (globals_key);
00104   if (! g)
00105     {
00106       if ((g = (__cxa_eh_globals *)
00107        std::malloc (sizeof (__cxa_eh_globals))) == 0
00108       || __gthread_setspecific (globals_key, (void *) g) != 0)
00109         std::terminate ();
00110       g->caughtExceptions = 0;
00111       g->uncaughtExceptions = 0;
00112     }
00113 
00114   return g;
00115 #else
00116   return &globals_static;
00117 #endif
00118 }