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 #include <exception>
  32 #include <exception_ptr.h>
  33 #include "unwind-cxx.h"
  34
  35 using namespace __cxxabiv1;
  36
  37
  38 std::__exception_ptr::exception_ptr::exception_ptr() throw()
  39   : _M_exception_object(0)
  40 {
  41 }
  42
  43
  44 std::__exception_ptr::exception_ptr::exception_ptr(void* obj) throw()
  45   : _M_exception_object(obj)
  46 {
  47   _M_addref();
  48 }
  49
  50
  51 std::__exception_ptr::exception_ptr::exception_ptr(__safe_bool) throw()
  52   : _M_exception_object(0)
  53 {
  54 }
  55
  56
  57 std::__exception_ptr::exception_ptr::exception_ptr(
  58                         const exception_ptr& other) throw()
  59   : _M_exception_object(other._M_exception_object)
  60 {
  61   _M_addref();
  62 }
  63
  64
  65 std::__exception_ptr::exception_ptr::~exception_ptr() throw()
  66 {
  67   _M_release();
  68 }
  69
  70
  71 std::__exception_ptr::exception_ptr&
  72 std::__exception_ptr::exception_ptr::operator=(
  73                     const exception_ptr& other) throw()
  74 {
  75   exception_ptr(other).swap(*this);
  76   return *this;
  77 }
  78
  79
  80 void
  81 std::__exception_ptr::exception_ptr::_M_addref() throw()
  82 {
  83   if (_M_exception_object)
  84     {
  85       __cxa_exception *eh =
  86         __get_exception_header_from_obj (_M_exception_object);
  87       __gnu_cxx::__atomic_add_dispatch (&eh->referenceCount, 1);
  88     }
  89 }
  90
  91
  92 void
  93 std::__exception_ptr::exception_ptr::_M_release() throw()
  94 {
  95   if (_M_exception_object)
  96     {
  97       __cxa_exception *eh =
  98         __get_exception_header_from_obj (_M_exception_object);
  99       if (__gnu_cxx::__exchange_and_add_dispatch (&eh->referenceCount, -1) == 0)
 100         {
 101           if (eh->exceptionDestructor)
 102             eh->exceptionDestructor (_M_exception_object);
 103
 104           __cxa_free_exception (_M_exception_object);
 105           _M_exception_object = 0;
 106         }
 107     }
 108 }
 109
 110
 111 void*
 112 std::__exception_ptr::exception_ptr::_M_get() const throw()
 113 {
 114   return _M_exception_object;
 115 }
 116
 117
 118 void
 119 std::__exception_ptr::exception_ptr::_M_safe_bool_dummy()
 120 {
 121 }
 122
 123
 124 void
 125 std::__exception_ptr::exception_ptr::swap(exception_ptr &other) throw()
 126 {
 127   void *tmp = _M_exception_object;
 128   _M_exception_object = other._M_exception_object;
 129   other._M_exception_object = tmp;
 130 }
 131
 132
 133 bool
 134 std::__exception_ptr::exception_ptr::operator!() const throw()
 135 {
 136   return _M_exception_object == 0;
 137 }
 138
 139
 140 std::__exception_ptr::exception_ptr::operator __safe_bool() const throw()
 141 {
 142   return _M_exception_object ? &exception_ptr::_M_safe_bool_dummy : 0;
 143 }
 144
 145
 146 const std::type_info*
 147 std::__exception_ptr::exception_ptr::__cxa_exception_type() const throw()
 148 {
 149   __cxa_exception *eh = __get_exception_header_from_obj (_M_exception_object);
 150   return eh->exceptionType;
 151 }
 152
 153
 154 bool std::__exception_ptr::operator==(const exception_ptr& lhs,
 155                                       const exception_ptr& rhs) throw()
 156 {
 157   return lhs._M_exception_object == rhs._M_exception_object;
 158 }
 159
 160
 161 bool std::__exception_ptr::operator!=(const exception_ptr& lhs,
 162                                       const exception_ptr& rhs) throw()
 163 {
 164   return !(lhs == rhs);
 165 }
 166
 167
 168 std::exception_ptr
 169 std::current_exception() throw()
 170 {
 171   __cxa_eh_globals *globals = __cxa_get_globals ();
 172   __cxa_exception *header = globals->caughtExceptions;
 173
 174   if (!header)
 175     return std::exception_ptr();
 176
 177   // Since foreign exceptions can't be counted, we can't return them.
 178   if (!__is_gxx_exception_class (header->unwindHeader.exception_class))
 179     return std::exception_ptr();
 180
 181   return std::exception_ptr(
 182     __get_object_from_ambiguous_exception (header));
 183 }
 184
 185
 186 static void
 187 __gxx_dependent_exception_cleanup (_Unwind_Reason_Code code,
 188                                    _Unwind_Exception *exc)
 189 {
 190   // This cleanup is set only for dependents.
 191   __cxa_dependent_exception *dep = __get_dependent_exception_from_ue (exc);
 192   __cxa_exception *header =
 193     __get_exception_header_from_obj (dep->primaryException);
 194
 195   // We only want to be called through _Unwind_DeleteException.
 196   // _Unwind_DeleteException in the HP-UX IA64 libunwind library
 197   // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
 198   // like the GCC _Unwind_DeleteException function does.
 199   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
 200     __terminate (header->terminateHandler);
 201
 202   if (__gnu_cxx::__exchange_and_add_dispatch (&header->referenceCount, -1) == 0)
 203     {
 204       if (header->exceptionDestructor)
 205         header->exceptionDestructor (header + 1);
 206
 207       __cxa_free_exception (header + 1);
 208     }
 209 }
 210
 211
 212 void
 213 std::rethrow_exception(std::exception_ptr ep)
 214 {
 215   void *obj = ep._M_get();
 216   __cxa_exception *eh = __get_exception_header_from_obj (obj);
 217
 218   __cxa_dependent_exception *dep = __cxa_allocate_dependent_exception ();
 219   dep->primaryException = obj;
 220   __gnu_cxx::__atomic_add_dispatch (&eh->referenceCount, 1);
 221
 222   dep->unexpectedHandler = __unexpected_handler;
 223   dep->terminateHandler = __terminate_handler;
 224   __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(dep->unwindHeader.exception_class);
 225   dep->unwindHeader.exception_cleanup = __gxx_dependent_exception_cleanup;
 226
 227 #ifdef _GLIBCXX_SJLJ_EXCEPTIONS
 228   _Unwind_SjLj_RaiseException (&dep->unwindHeader);
 229 #else
 230   _Unwind_RaiseException (&dep->unwindHeader);
 231 #endif
 232
 233   // Some sort of unwinding error.  Note that terminate is a handler.
 234   __cxa_begin_catch (&dep->unwindHeader);
 235   std::terminate ();
 236 }