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

   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
  37 using namespace __cxxabiv1;
  38
  39
  40 // Single-threaded fallback buffer.
  41 static __cxa_eh_globals globals_static;
  42
  43 #if __GTHREADS
  44 static __gthread_key_t globals_key;
  45 static int use_thread_key = -1;
  46
  47 static void
  48 get_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
  64 static void
  65 get_globals_init ()
  66 {
  67   use_thread_key =
  68     (__gthread_key_create (&globals_key, get_globals_dtor) == 0);
  69 }
  70
  71 static void
  72 get_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
  81 extern "C" __cxa_eh_globals *
  82 __cxxabiv1::__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
  94 extern "C" __cxa_eh_globals *
  95 __cxxabiv1::__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 }