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

   1 // -*- C++ -*- Implement the members of exception_ptr.
   2 // Copyright (C) 2008, 2009, 2010 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 std::__exception_ptr::exception_ptr::exception_ptr(void* obj) throw()
  42 : _M_exception_object(obj)  { _M_addref(); }
  43
  44
  45 std::__exception_ptr::exception_ptr::exception_ptr(__safe_bool) throw()
  46 : _M_exception_object(0) { }
  47
  48
  49 std::__exception_ptr::
  50 exception_ptr::exception_ptr(const exception_ptr& other) throw()
  51 : _M_exception_object(other._M_exception_object)
  52 { _M_addref(); }
  53
  54
  55 std::__exception_ptr::exception_ptr::~exception_ptr() throw()
  56 { _M_release(); }
  57
  58
  59 std::__exception_ptr::exception_ptr&
  60 std::__exception_ptr::
  61 exception_ptr::operator=(const exception_ptr& other) throw()
  62 {
  63   exception_ptr(other).swap(*this);
  64   return *this;
  65 }
  66
  67
  68 void
  69 std::__exception_ptr::exception_ptr::_M_addref() throw()
  70 {
  71   if (_M_exception_object)
  72     {
  73       __cxa_refcounted_exception *eh =
  74         __get_refcounted_exception_header_from_obj (_M_exception_object);
  75       __sync_add_and_fetch (&eh->referenceCount, 1);
  76     }
  77 }
  78
  79
  80 void
  81 std::__exception_ptr::exception_ptr::_M_release() throw()
  82 {
  83   if (_M_exception_object)
  84     {
  85       __cxa_refcounted_exception *eh =
  86         __get_refcounted_exception_header_from_obj (_M_exception_object);
  87       if (__sync_sub_and_fetch (&eh->referenceCount, 1) == 0)
  88         {
  89           if (eh->exc.exceptionDestructor)
  90             eh->exc.exceptionDestructor (_M_exception_object);
  91
  92           __cxa_free_exception (_M_exception_object);
  93           _M_exception_object = 0;
  94         }
  95     }
  96 }
  97
  98
  99 void*
 100 std::__exception_ptr::exception_ptr::_M_get() const throw()
 101 { return _M_exception_object; }
 102
 103
 104 void
 105 std::__exception_ptr::exception_ptr::swap(exception_ptr &other) throw()
 106 {
 107   void *tmp = _M_exception_object;
 108   _M_exception_object = other._M_exception_object;
 109   other._M_exception_object = tmp;
 110 }
 111
 112
 113 // Retained for compatibility with CXXABI_1.3.
 114 void
 115 std::__exception_ptr::exception_ptr::_M_safe_bool_dummy() throw () { }
 116
 117
 118 // Retained for compatibility with CXXABI_1.3.
 119 bool
 120 std::__exception_ptr::exception_ptr::operator!() const throw()
 121 { return _M_exception_object == 0; }
 122
 123
 124 // Retained for compatibility with CXXABI_1.3.
 125 std::__exception_ptr::exception_ptr::operator __safe_bool() const throw()
 126 {
 127   return _M_exception_object ? &exception_ptr::_M_safe_bool_dummy : 0;
 128 }
 129
 130
 131 const std::type_info*
 132 std::__exception_ptr::exception_ptr::__cxa_exception_type() const throw()
 133 {
 134   __cxa_exception *eh = __get_exception_header_from_obj (_M_exception_object);
 135   return eh->exceptionType;
 136 }
 137
 138
 139 bool std::__exception_ptr::operator==(const exception_ptr& lhs,
 140                                       const exception_ptr& rhs) throw()
 141 { return lhs._M_exception_object == rhs._M_exception_object; }
 142
 143
 144 bool std::__exception_ptr::operator!=(const exception_ptr& lhs,
 145                                       const exception_ptr& rhs) throw()
 146 { return !(lhs == rhs);}
 147
 148
 149 std::exception_ptr
 150 std::current_exception() throw()
 151 {
 152   __cxa_eh_globals *globals = __cxa_get_globals ();
 153   __cxa_exception *header = globals->caughtExceptions;
 154
 155   if (!header)
 156     return std::exception_ptr();
 157
 158   // Since foreign exceptions can't be counted, we can't return them.
 159   if (!__is_gxx_exception_class (header->unwindHeader.exception_class))
 160     return std::exception_ptr();
 161
 162   return std::exception_ptr(
 163     __get_object_from_ambiguous_exception (header));
 164 }
 165
 166
 167 static void
 168 __gxx_dependent_exception_cleanup(_Unwind_Reason_Code code,
 169                                   _Unwind_Exception *exc)
 170 {
 171   // This cleanup is set only for dependents.
 172   __cxa_dependent_exception *dep = __get_dependent_exception_from_ue (exc);
 173   __cxa_refcounted_exception *header =
 174     __get_refcounted_exception_header_from_obj (dep->primaryException);
 175
 176   // We only want to be called through _Unwind_DeleteException.
 177   // _Unwind_DeleteException in the HP-UX IA64 libunwind library
 178   // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
 179   // like the GCC _Unwind_DeleteException function does.
 180   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
 181     __terminate (header->exc.terminateHandler);
 182
 183   __cxa_free_dependent_exception (dep);
 184
 185   if (__sync_sub_and_fetch (&header->referenceCount, 1) == 0)
 186     {
 187       if (header->exc.exceptionDestructor)
 188         header->exc.exceptionDestructor (header + 1);
 189
 190       __cxa_free_exception (header + 1);
 191     }
 192 }
 193
 194
 195 void
 196 std::rethrow_exception(std::exception_ptr ep)
 197 {
 198   void *obj = ep._M_get();
 199   __cxa_refcounted_exception *eh
 200     = __get_refcounted_exception_header_from_obj (obj);
 201
 202   __cxa_dependent_exception *dep = __cxa_allocate_dependent_exception ();
 203   dep->primaryException = obj;
 204   __sync_add_and_fetch (&eh->referenceCount, 1);
 205
 206   dep->unexpectedHandler = __unexpected_handler;
 207   dep->terminateHandler = __terminate_handler;
 208   __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(dep->unwindHeader.exception_class);
 209   dep->unwindHeader.exception_cleanup = __gxx_dependent_exception_cleanup;
 210
 211 #ifdef _GLIBCXX_SJLJ_EXCEPTIONS
 212   _Unwind_SjLj_RaiseException (&dep->unwindHeader);
 213 #else
 214   _Unwind_RaiseException (&dep->unwindHeader);
 215 #endif
 216
 217   // Some sort of unwinding error.  Note that terminate is a handler.
 218   __cxa_begin_catch (&dep->unwindHeader);
 219   std::terminate();
 220 }
 221
 222 #undef _GLIBCXX_EH_PTR_COMPAT
 223
 224 #endif