libstdc++-v3/libsupc++/eh_globals.cc

   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 "unwind-cxx.h"
  33 #include "gthr.h"
  34
  35 using namespace __cxxabiv1;
  36
  37
  38 // Single-threaded fallback buffer.
  39 static __cxa_eh_globals globals_static;
  40
  41 #if __GTHREADS
  42 static __gthread_key_t globals_key;
  43 static int use_thread_key = -1;
  44
  45 static void
  46 get_globals_dtor (void *ptr)
  47 {
  48   __gthread_key_dtor (globals_key, ptr);
  49   if (ptr)
  50     free (ptr);
  51 }
  52
  53 static void
  54 get_globals_init ()
  55 {
  56   use_thread_key =
  57     (__gthread_key_create (&globals_key, get_globals_dtor) == 0);
  58 }
  59
  60 static void
  61 get_globals_init_once ()
  62 {
  63   static __gthread_once_t once = __GTHREAD_ONCE_INIT;
  64   if (__gthread_once (&once, get_globals_init) != 0
  65       || use_thread_key < 0)
  66     use_thread_key = 0;
  67 }
  68 #endif
  69
  70 extern "C" __cxa_eh_globals *
  71 __cxa_get_globals_fast ()
  72 {
  73 #if __GTHREADS
  74   if (use_thread_key)
  75     return (__cxa_eh_globals *) __gthread_getspecific (globals_key);
  76   else
  77     return &globals_static;
  78 #else
  79   return &globals_static;
  80 #endif
  81 }
  82
  83 extern "C" __cxa_eh_globals *
  84 __cxa_get_globals ()
  85 {
  86 #if __GTHREADS
  87   __cxa_eh_globals *g;
  88
  89   if (use_thread_key == 0)
  90     return &globals_static;
  91
  92   if (use_thread_key < 0)
  93     get_globals_init_once ();
  94
  95   g = (__cxa_eh_globals *) __gthread_getspecific (globals_key);
  96   if (! g)
  97     {
  98       static __gthread_once_t once = __GTHREAD_ONCE_INIT;
  99
 100       // Make sure use_thread_key got initialized.  Some systems have
 101       // dummy thread routines in their libc that return a success.
 102       if (__gthread_once (&once, eh_threads_initialize) != 0
 103           || use_thread_key < 0)
 104         {
 105           use_thread_key = 0;
 106           return &globals_static;
 107         }
 108
 109       if ((g = malloc (sizeof (__cxa_eh_globals))) == 0
 110           || __gthread_setspecific (eh_context_key, (void *) g) != 0)
 111         std::terminate ();
 112       g->caughtExceptions = 0;
 113       g->uncaughtExceptions = 0;
 114     }
 115
 116   return g;
 117 #else
 118   return &globals_static;
 119 #endif
 120 }