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

   1 // -*- C++ -*- Implement the members of exception_ptr.
   2 // Copyright (C) 2008, 2009 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 3, 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 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #include <bits/c++config.h>
  26
  27 #ifdef _GLIBCXX_ATOMIC_BUILTINS_4
  28
  29 #define _GLIBCXX_EH_PTR_COMPAT
  30
  31 #include <exception>
  32 #include <exception_ptr.h>
  33 #include "unwind-cxx.h"
  34
  35 using namespace __cxxabiv1;
  36
  37 std::__exception_ptr::exception_ptr::exception_ptr() throw()
  38   : _M_exception_object(0)
  39 {
  40 }
  41
  42
  43 std::__exception_ptr::exception_ptr::exception_ptr(void* obj) throw()
  44   : _M_exception_object(obj)
  45 {
  46   _M_addref();
  47 }
  48
  49
  50 std::__exception_ptr::exception_ptr::exception_ptr(__safe_bool) throw()
  51   : _M_exception_object(0)
  52 {
  53 }
  54
  55
  56 std::__exception_ptr::exception_ptr::exception_ptr(
  57                         const exception_ptr& other) throw()
  58   : _M_exception_object(other._M_exception_object)
  59 {
  60   _M_addref();
  61 }
  62
  63
  64 std::__exception_ptr::exception_ptr::~exception_ptr() throw()
  65 {
  66   _M_release();
  67 }
  68
  69
  70 std::__exception_ptr::exception_ptr&
  71 std::__exception_ptr::exception_ptr::operator=(
  72                     const exception_ptr& other) throw()
  73 {
  74   exception_ptr(other).swap(*this);
  75   return *this;
  76 }
  77
  78
  79 void
  80 std::__exception_ptr::exception_ptr::_M_addref() throw()
  81 {
  82   if (_M_exception_object)
  83     {
  84       __cxa_refcounted_exception *eh =
  85         __get_refcounted_exception_header_from_obj (_M_exception_object);
  86       __sync_add_and_fetch (&eh->referenceCount, 1);
  87     }
  88 }
  89
  90
  91 void
  92 std::__exception_ptr::exception_ptr::_M_release() throw()
  93 {
  94   if (_M_exception_object)
  95     {
  96       __cxa_refcounted_exception *eh =
  97         __get_refcounted_exception_header_from_obj (_M_exception_object);
  98       if (__sync_sub_and_fetch (&eh->referenceCount, 1) == 0)
  99         {
 100           if (eh->exc.exceptionDestructor)
 101             eh->exc.exceptionDestructor (_M_exception_object);
 102
 103           __cxa_free_exception (_M_exception_object);
 104           _M_exception_object = 0;
 105         }
 106     }
 107 }
 108
 109
 110 void*
 111 std::__exception_ptr::exception_ptr::_M_get() const throw()
 112 {
 113   return _M_exception_object;
 114 }
 115
 116
 117 void
 118 std::__exception_ptr::exception_ptr::_M_safe_bool_dummy() throw ()
 119 {
 120 }
 121
 122
 123 void
 124 std::__exception_ptr::exception_ptr::swap(exception_ptr &other) throw()
 125 {
 126   void *tmp = _M_exception_object;
 127   _M_exception_object = other._M_exception_object;
 128   other._M_exception_object = tmp;
 129 }
 130
 131
 132 // Retained for compatibility with CXXABI_1.3.
 133 bool
 134 std::__exception_ptr::exception_ptr::operator!() const throw()
 135 {
 136   return _M_exception_object == 0;
 137 }
 138
 139
 140 // Retained for compatibility with CXXABI_1.3.
 141 std::__exception_ptr::exception_ptr::operator __safe_bool() const throw()
 142 {
 143   return _M_exception_object ? &exception_ptr::_M_safe_bool_dummy : 0;
 144 }
 145
 146
 147 const std::type_info*
 148 std::__exception_ptr::exception_ptr::__cxa_exception_type() const throw()
 149 {
 150   __cxa_exception *eh = __get_exception_header_from_obj (_M_exception_object);
 151   return eh->exceptionType;
 152 }
 153
 154
 155 bool std::__exception_ptr::operator==(const exception_ptr& lhs,
 156                                       const exception_ptr& rhs) throw()
 157 {
 158   return lhs._M_exception_object == rhs._M_exception_object;
 159 }
 160
 161
 162 bool std::__exception_ptr::operator!=(const exception_ptr& lhs,
 163                                       const exception_ptr& rhs) throw()
 164 {
 165   return !(lhs == rhs);
 166 }
 167
 168
 169 std::exception_ptr
 170 std::current_exception() throw()
 171 {
 172   __cxa_eh_globals *globals = __cxa_get_globals ();
 173   __cxa_exception *header = globals->caughtExceptions;
 174
 175   if (!header)
 176     return std::exception_ptr();
 177
 178   // Since foreign exceptions can't be counted, we can't return them.
 179   if (!__is_gxx_exception_class (header->unwindHeader.exception_class))
 180     return std::exception_ptr();
 181
 182   return std::exception_ptr(
 183     __get_object_from_ambiguous_exception (header));
 184 }
 185
 186
 187 static void
 188 __gxx_dependent_exception_cleanup (_Unwind_Reason_Code code,
 189                                    _Unwind_Exception *exc)
 190 {
 191   // This cleanup is set only for dependents.
 192   __cxa_dependent_exception *dep = __get_dependent_exception_from_ue (exc);
 193   __cxa_refcounted_exception *header =
 194     __get_refcounted_exception_header_from_obj (dep->primaryException);
 195
 196   // We only want to be called through _Unwind_DeleteException.
 197   // _Unwind_DeleteException in the HP-UX IA64 libunwind library
 198   // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
 199   // like the GCC _Unwind_DeleteException function does.
 200   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
 201     __terminate (header->exc.terminateHandler);
 202
 203   __cxa_free_dependent_exception (dep);
 204
 205   if (__sync_sub_and_fetch (&header->referenceCount, 1) == 0)
 206     {
 207       if (header->exc.exceptionDestructor)
 208         header->exc.exceptionDestructor (header + 1);
 209
 210       __cxa_free_exception (header + 1);
 211     }
 212 }
 213
 214
 215 void
 216 std::rethrow_exception(std::exception_ptr ep)
 217 {
 218   void *obj = ep._M_get();
 219   __cxa_refcounted_exception *eh
 220     = __get_refcounted_exception_header_from_obj (obj);
 221
 222   __cxa_dependent_exception *dep = __cxa_allocate_dependent_exception ();
 223   dep->primaryException = obj;
 224   __sync_add_and_fetch (&eh->referenceCount, 1);
 225
 226   dep->unexpectedHandler = __unexpected_handler;
 227   dep->terminateHandler = __terminate_handler;
 228   __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(dep->unwindHeader.exception_class);
 229   dep->unwindHeader.exception_cleanup = __gxx_dependent_exception_cleanup;
 230
 231 #ifdef _GLIBCXX_SJLJ_EXCEPTIONS
 232   _Unwind_SjLj_RaiseException (&dep->unwindHeader);
 233 #else
 234   _Unwind_RaiseException (&dep->unwindHeader);
 235 #endif
 236
 237   // Some sort of unwinding error.  Note that terminate is a handler.
 238   __cxa_begin_catch (&dep->unwindHeader);
 239   std::terminate ();
 240 }
 241
 242 #undef _GLIBCXX_EH_PTR_COMPAT
 243
 244 #endif