gcc/libstdc++-v3/libsupc++/eh_tm.cc
2024-01-03 12:19:35 +01:00

126 lines
3.7 KiB
C++

// -*- C++ -*- Exception handling routines for Transactional Memory.
// Copyright (C) 2009-2024 Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// GCC is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3, or (at your option)
// any later version.
//
// GCC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#include <cstdlib>
#include "unwind-cxx.h"
#include "eh_atomics.h"
using namespace __cxxabiv1;
// Free one C++ exception.
static void
free_any_cxa_exception (_Unwind_Exception *eo)
{
__cxa_refcounted_exception *h
= __get_refcounted_exception_header_from_ue (eo);
if (__is_dependent_exception (eo->exception_class))
{
__cxa_dependent_exception *dep
= __get_dependent_exception_from_ue (eo);
h = __get_refcounted_exception_header_from_obj (dep->primaryException);
__cxa_free_dependent_exception (dep);
}
if (__gnu_cxx::__eh_atomic_dec (&h->referenceCount))
__cxa_free_exception (h + 1);
}
// Cleanup exception handling state while rolling back state for
// a software transactional memory transaction.
//
// UNTHROWN_OBJ is non-null if we've called __cxa_allocate_exception
// but not yet called __cxa_throw for it.
//
// CLEANUP_EXC is non-null if we're currently processing a cleanup
// along an exception path, but we've not caught the exception yet.
//
// CAUGHT_COUNT is the nesting depth of __cxa_begin_catch within
// the transaction; undo as if calling __cxa_end_catch that many times.
extern "C" void
__cxxabiv1::__cxa_tm_cleanup (void *unthrown_obj,
void *cleanup_exc,
unsigned int caught_count) throw()
{
__cxa_eh_globals *globals = __cxa_get_globals_fast ();
// Handle a C++ exception not yet thrown.
if (unthrown_obj)
{
globals->uncaughtExceptions -= 1;
__cxa_free_exception (unthrown_obj);
}
// Handle an exception not yet caught ie. processing a cleanup
// in between the throw and the catch.
if (cleanup_exc)
{
_Unwind_Exception *eo
= reinterpret_cast <_Unwind_Exception *>(cleanup_exc);
if (__is_gxx_exception_class (eo->exception_class))
free_any_cxa_exception (eo);
else
_Unwind_DeleteException (eo);
}
// Do __cxa_end_catch caught_count times, but don't bother running
// the destructors for the objects involved. All of that is being
// undone by the transaction restart.
if (caught_count > 0)
{
__cxa_exception *h = globals->caughtExceptions;
// Rethrown foreign exceptions are removed from the stack immediately.
// We would have freed this exception via THIS_EXC above.
if (h == NULL)
return;
do
{
__cxa_exception *next;
_Unwind_Exception *eo = &h->unwindHeader;
if (__is_gxx_exception_class (eo->exception_class))
{
next = h->nextException;
free_any_cxa_exception (eo);
}
else
{
_Unwind_DeleteException (eo);
next = 0;
}
h = next;
}
while (--caught_count);
globals->caughtExceptions = h;
}
}