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// -*- C++ -*- Exception handling routines for Transactional Memory.

// Copyright (C) 2009, 2011, 2012 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"

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 __GCC_ATOMIC_INT_LOCK_FREE > 1

  if (__atomic_sub_fetch (&h->referenceCount, 1, __ATOMIC_ACQ_REL) == 0)

#endif

    __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;

    }

}