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/* Copyright (C) 2008, 2009, 2011, 2012 Free Software Foundation, Inc.

   Contributed by Richard Henderson <rth@redhat.com>.

   This file is part of the GNU Transactional Memory Library (libitm).

   Libitm 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 of the License, or

   (at your option) any later version.

   Libitm 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 "libitm_i.h"

namespace GTM HIDDEN {

// This function needs to be noinline because we need to prevent that it gets

// inlined into another function that calls further functions. This could

// break our assumption that we only call memcpy and thus only need to

// additionally protect the memcpy stack (see the hack in mask_stack_bottom()).

// Even if that isn't an issue because those other calls don't happen during

// copying, we still need mask_stack_bottom() to be called "close" to the

// memcpy in terms of stack frames, so just ensure that for now using the

// noinline.

void __attribute__((noinline))

gtm_undolog::rollback (gtm_thread* tx, size_t until_size)

{

  size_t i, n = undolog.size();

  void *top = mask_stack_top(tx);

  void *bot = mask_stack_bottom(tx);

  if (n > 0)

    {

      for (i = n; i-- > until_size; )

        {

          void *ptr = (void *) undolog[i--];

          size_t len = undolog[i];

          size_t words = (len + sizeof(gtm_word) - 1) / sizeof(gtm_word);

          i -= words;

          // Filter out any updates that overlap the libitm stack.  We don't

          // bother filtering out just the overlapping bytes because we don't

          // merge writes and thus any overlapping write is either bogus or

          // would restore data on stack frames that are not in use anymore.

          // FIXME The memcpy can/will end up as another call but we

          // calculated BOT based on the current function.  Can we inline or

          // reimplement this without too much trouble due to unaligned calls

          // and still have good performance, so that we can remove the hack

          // in mask_stack_bottom()?

          if (likely(ptr > top || (uint8_t*)ptr + len <= bot))

            __builtin_memcpy (ptr, &undolog[i], len);

        }

      undolog.set_size(until_size);

    }

}

void ITM_REGPARM

GTM_LB (const void *ptr, size_t len)

{

  gtm_thread *tx = gtm_thr();

  tx->undolog.log(ptr, len);

}

} // namespace GTM

using namespace GTM;

/* ??? Use configure to determine if aliases are supported.  Or convince

   the compiler to not just tail call this, but actually generate the

   same_body_alias itself.  */

void ITM_REGPARM

_ITM_LB (const void *ptr, size_t len)

{

  GTM_LB (ptr, len);

}

#define ITM_LOG_DEF(T) \

void ITM_REGPARM _ITM_L##T (const _ITM_TYPE_##T *ptr) \

{ GTM_LB (ptr, sizeof (*ptr)); }

ITM_LOG_DEF(U1)

ITM_LOG_DEF(U2)

ITM_LOG_DEF(U4)

ITM_LOG_DEF(U8)

ITM_LOG_DEF(F)

ITM_LOG_DEF(D)

ITM_LOG_DEF(E)

ITM_LOG_DEF(CF)

ITM_LOG_DEF(CD)

ITM_LOG_DEF(CE)