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

   1 // -*- C++ -*- Implement the members of exception_ptr.
   2 // Copyright (C) 2008-2014 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 #include <bits/atomic_lockfree_defines.h>
  27
  28 #if ATOMIC_INT_LOCK_FREE > 1
  29
  30 #define _GLIBCXX_EH_PTR_COMPAT
  31
  32 #include <exception>
  33 #include <bits/exception_ptr.h>
  34 #include "unwind-cxx.h"
  35
  36 using namespace __cxxabiv1;
  37
  38 std::__exception_ptr::exception_ptr::exception_ptr() _GLIBCXX_USE_NOEXCEPT
  39 : _M_exception_object(0) { }
  40
  41
  42 std::__exception_ptr::exception_ptr::exception_ptr(void* obj)
  43 _GLIBCXX_USE_NOEXCEPT
  44 : _M_exception_object(obj)  { _M_addref(); }
  45
  46
  47 std::__exception_ptr::exception_ptr::exception_ptr(__safe_bool)
  48 _GLIBCXX_USE_NOEXCEPT
  49 : _M_exception_object(0) { }
  50
  51
  52 std::__exception_ptr::
  53 exception_ptr::exception_ptr(const exception_ptr& other) _GLIBCXX_USE_NOEXCEPT
  54 : _M_exception_object(other._M_exception_object)
  55 { _M_addref(); }
  56
  57
  58 std::__exception_ptr::exception_ptr::~exception_ptr() _GLIBCXX_USE_NOEXCEPT
  59 { _M_release(); }
  60
  61
  62 std::__exception_ptr::exception_ptr&
  63 std::__exception_ptr::
  64 exception_ptr::operator=(const exception_ptr& other) _GLIBCXX_USE_NOEXCEPT
  65 {
  66   exception_ptr(other).swap(*this);
  67   return *this;
  68 }
  69
  70
  71 void
  72 std::__exception_ptr::exception_ptr::_M_addref() _GLIBCXX_USE_NOEXCEPT
  73 {
  74   if (_M_exception_object)
  75     {
  76       __cxa_refcounted_exception *eh =
  77         __get_refcounted_exception_header_from_obj (_M_exception_object);
  78       __atomic_add_fetch (&eh->referenceCount, 1, __ATOMIC_ACQ_REL);
  79     }
  80 }
  81
  82
  83 void
  84 std::__exception_ptr::exception_ptr::_M_release() _GLIBCXX_USE_NOEXCEPT
  85 {
  86   if (_M_exception_object)
  87     {
  88       __cxa_refcounted_exception *eh =
  89         __get_refcounted_exception_header_from_obj (_M_exception_object);
  90       if (__atomic_sub_fetch (&eh->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)
  91         {
  92           if (eh->exc.exceptionDestructor)
  93             eh->exc.exceptionDestructor (_M_exception_object);
  94
  95           __cxa_free_exception (_M_exception_object);
  96           _M_exception_object = 0;
  97         }
  98     }
  99 }
 100
 101
 102 void*
 103 std::__exception_ptr::exception_ptr::_M_get() const _GLIBCXX_USE_NOEXCEPT
 104 { return _M_exception_object; }
 105
 106
 107 void
 108 std::__exception_ptr::exception_ptr::swap(exception_ptr &other)
 109   _GLIBCXX_USE_NOEXCEPT
 110 {
 111   void *tmp = _M_exception_object;
 112   _M_exception_object = other._M_exception_object;
 113   other._M_exception_object = tmp;
 114 }
 115
 116
 117 // Retained for compatibility with CXXABI_1.3.
 118 void
 119 std::__exception_ptr::exception_ptr::_M_safe_bool_dummy()
 120   _GLIBCXX_USE_NOEXCEPT { }
 121
 122
 123 // Retained for compatibility with CXXABI_1.3.
 124 bool
 125 std::__exception_ptr::exception_ptr::operator!() const _GLIBCXX_USE_NOEXCEPT
 126 { return _M_exception_object == 0; }
 127
 128
 129 // Retained for compatibility with CXXABI_1.3.
 130 std::__exception_ptr::exception_ptr::operator __safe_bool() const
 131 _GLIBCXX_USE_NOEXCEPT
 132 {
 133   return _M_exception_object ? &exception_ptr::_M_safe_bool_dummy : 0;
 134 }
 135
 136
 137 const std::type_info*
 138 std::__exception_ptr::exception_ptr::__cxa_exception_type() const
 139   _GLIBCXX_USE_NOEXCEPT
 140 {
 141   __cxa_exception *eh = __get_exception_header_from_obj (_M_exception_object);
 142   return eh->exceptionType;
 143 }
 144
 145
 146 bool std::__exception_ptr::operator==(const exception_ptr& lhs,
 147                                       const exception_ptr& rhs)
 148   _GLIBCXX_USE_NOEXCEPT
 149 { return lhs._M_exception_object == rhs._M_exception_object; }
 150
 151
 152 bool std::__exception_ptr::operator!=(const exception_ptr& lhs,
 153                                       const exception_ptr& rhs)
 154   _GLIBCXX_USE_NOEXCEPT
 155 { return !(lhs == rhs);}
 156
 157
 158 std::exception_ptr
 159 std::current_exception() _GLIBCXX_USE_NOEXCEPT
 160 {
 161   __cxa_eh_globals *globals = __cxa_get_globals ();
 162   __cxa_exception *header = globals->caughtExceptions;
 163
 164   if (!header)
 165     return std::exception_ptr();
 166
 167   // Since foreign exceptions can't be counted, we can't return them.
 168   if (!__is_gxx_exception_class (header->unwindHeader.exception_class))
 169     return std::exception_ptr();
 170
 171   return std::exception_ptr(
 172     __get_object_from_ambiguous_exception (header));
 173 }
 174
 175
 176 static void
 177 __gxx_dependent_exception_cleanup(_Unwind_Reason_Code code,
 178                                   _Unwind_Exception *exc)
 179 {
 180   // This cleanup is set only for dependents.
 181   __cxa_dependent_exception *dep = __get_dependent_exception_from_ue (exc);
 182   __cxa_refcounted_exception *header =
 183     __get_refcounted_exception_header_from_obj (dep->primaryException);
 184
 185   // We only want to be called through _Unwind_DeleteException.
 186   // _Unwind_DeleteException in the HP-UX IA64 libunwind library
 187   // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
 188   // like the GCC _Unwind_DeleteException function does.
 189   if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
 190     __terminate (header->exc.terminateHandler);
 191
 192   __cxa_free_dependent_exception (dep);
 193
 194   if (__atomic_sub_fetch (&header->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)
 195     {
 196       if (header->exc.exceptionDestructor)
 197         header->exc.exceptionDestructor (header + 1);
 198
 199       __cxa_free_exception (header + 1);
 200     }
 201 }
 202
 203
 204 void
 205 std::rethrow_exception(std::exception_ptr ep)
 206 {
 207   void *obj = ep._M_get();
 208   __cxa_refcounted_exception *eh
 209     = __get_refcounted_exception_header_from_obj (obj);
 210
 211   __cxa_dependent_exception *dep = __cxa_allocate_dependent_exception ();
 212   dep->primaryException = obj;
 213   __atomic_add_fetch (&eh->referenceCount, 1,  __ATOMIC_ACQ_REL);
 214
 215   dep->unexpectedHandler = get_unexpected ();
 216   dep->terminateHandler = get_terminate ();
 217   __GXX_INIT_DEPENDENT_EXCEPTION_CLASS(dep->unwindHeader.exception_class);
 218   dep->unwindHeader.exception_cleanup = __gxx_dependent_exception_cleanup;
 219
 220 #ifdef _GLIBCXX_SJLJ_EXCEPTIONS
 221   _Unwind_SjLj_RaiseException (&dep->unwindHeader);
 222 #else
 223   _Unwind_RaiseException (&dep->unwindHeader);
 224 #endif
 225
 226   // Some sort of unwinding error.  Note that terminate is a handler.
 227   __cxa_begin_catch (&dep->unwindHeader);
 228   std::terminate();
 229 }
 230
 231 #undef _GLIBCXX_EH_PTR_COMPAT
 232
 233 #endif