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

   1 // -*- C++ -*- Implement the members of exception_ptr.
   2 // Copyright (C) 2008 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, 51 Franklin Street, Fifth Floor,
  19 // Boston, MA 02110-1301, 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 #include <bits/c++config.h>
  31
  32 #ifdef _GLIBCXX_ATOMIC_BUILTINS_4
  33
  34 #include <exception>
  35 #include <exception_ptr.h>
  36 #include "unwind-cxx.h"
  37
  38 using namespace __cxxabiv1;
  39
  40 std::__exception_ptr::exception_ptr::exception_ptr() throw()
  41   : _M_exception_object(0)
  42 {
  43 }
  44
  45
  46 std::__exception_ptr::exception_ptr::exception_ptr(void* obj) throw()
  47   : _M_exception_object(obj)
  48 {
  49   _M_addref();
  50 }
  51
  52
  53 std::__exception_ptr::exception_ptr::exception_ptr(__safe_bool) throw()
  54   : _M_exception_object(0)
  55 {
  56 }
  57
  58
  59 std::__exception_ptr::exception_ptr::exception_ptr(
  60                         const exception_ptr& other) throw()
  61   : _M_exception_object(other._M_exception_object)
  62 {
  63   _M_addref();
  64 }
  65
  66
  67 std::__exception_ptr::exception_ptr::~exception_ptr() throw()
  68 {
  69   _M_release();
  70 }
  71
  72
  73 std::__exception_ptr::exception_ptr&
  74 std::__exception_ptr::exception_ptr::operator=(
  75                     const exception_ptr& other) throw()
  76 {
  77   exception_ptr(other).swap(*this);
  78   return *this;
  79 }
  80
  81
  82 void
  83 std::__exception_ptr::exception_ptr::_M_addref() throw()
  84 {
  85   if (_M_exception_object)
  86     {
  87       __cxa_exception *eh =
  88         __get_exception_header_from_obj (_M_exception_object);
  89       __sync_add_and_fetch (&eh->referenceCount, 1);
  90     }
  91 }
  92
  93
  94 void
  95 std::__exception_ptr::exception_ptr::_M_release() throw()
  96 {
  97   if (_M_exception_object)
  98     {
  99       __cxa_exception *eh =
 100         __get_exception_header_from_obj (_M_exception_object);
 101       if (__sync_sub_and_fetch (&eh->referenceCount, 1) == 0)
 102         {
 103           if (eh->exceptionDestructor)
 104             eh->exceptionDestructor (_M_exception_object);
 105
 106           __cxa_free_exception (_M_exception_object);
 107           _M_exception_object = 0;
 108         }
 109     }
 110 }
 111
 112
 113 void*
 114 std::__exception_ptr::exception_ptr::_M_get() const throw()
 115 {
 116   return _M_exception_object;
 117 }
 118
 119
 120 void
 121 std::__exception_ptr::exception_ptr::_M_safe_bool_dummy()
 122 {
 123 }
 124
 125
 126 void
 127 std::__exception_ptr::exception_ptr::swap(exception_ptr &other) throw()
 128 {
 129   void *tmp = _M_exception_object;
 130   _M_exception_object = other._M_exception_object;
 131   other._M_exception_object = tmp;
 132 }
 133
 134
 135 bool
 136 std::__exception_ptr::exception_ptr::operator!() const throw()
 137 {
 138   return _M_exception_object == 0;
 139 }
 140
 141
 142 std::__exception_ptr::exception_ptr::operator __safe_bool() const throw()
 143 {
 144   return _M_exception_object ? &exception_ptr::_M_safe_bool_dummy : 0;
 145 }
 146
 147
 148 const std::type_info*
 149 std::__exception_ptr::exception_ptr::__cxa_exception_type() const throw()
 150 {
 151   __cxa_exception *eh = __get_exception_header_from_obj (_M_exception_object);
 152   return eh->exceptionType;
 153 }
 154
 155
 156 bool std::__exception_ptr::operator==(const exception_ptr& lhs,
 157                                       const exception_ptr& rhs) throw()
 158 {
 159   return lhs._M_exception_object == rhs._M_exception_object;
 160 }
 161
 162
 163 bool std::__exception_ptr::operator!=(const exception_ptr& lhs,
 164                                       const exception_ptr& rhs) throw()
 165 {
 166   return !(lhs == rhs);
 167 }
 168
 169
 170 std::exception_ptr
 171 std::current_exception() throw()
 172 {
 173   __cxa_eh_globals *globals = __cxa_get_globals ();
 174   __cxa_exception *header = globals->caughtExceptions;
 175
 176   if (!header)
 177     return std::exception_ptr();
 178
 179   // Since foreign exceptions can't be counted, we can't return them.
 180   if (!__is_gxx_exception_class (header->unwindHeader.exception_class))
 181     return std::exception_ptr();
 182
 183   return std::exception_ptr(
 184     __get_object_from_ambiguous_exception (header));
 185 }
 186
 187
 188 static void
 189 __gxx_dependent_exception_cleanup (_Unwind_Reason_Code code,
 190                                    _Unwind_Exception *exc)
 191 {
 192   // This cleanup is set only for dependents.
 193   __cxa_dependent_exception *dep = __get_dependent_exception_from_ue (exc);
 194   __cxa_exception *header =
 195     __get_exception_header_from_obj (dep->primaryException);
 196
 197   // We only want to be called through _Unwind_DeleteException.
 198   // _Unwind_DeleteException in the HP-UX IA64 libunwind library
 199   // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
 200   // like the GCC _Unwind_DeleteException function does.
 201   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
 202     __terminate (header->terminateHandler);
 203
 204   __cxa_free_dependent_exception (dep);
 205
 206   if (__sync_sub_and_fetch (&header->referenceCount, 1) == 0)
 207     {
 208       if (header->exceptionDestructor)
 209         header->exceptionDestructor (header + 1);
 210
 211       __cxa_free_exception (header + 1);
 212     }
 213 }
 214
 215
 216 void
 217 std::rethrow_exception(std::exception_ptr ep)
 218 {
 219   void *obj = ep._M_get();
 220   __cxa_exception *eh = __get_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 #endif