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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"
// Avoid a dependency on libstdc++ for the pure virtuals in abi_dispatch.
extern "C" void HIDDEN
__cxa_pure_virtual ()
{
abort ();
}
using namespace GTM;
namespace {
// This group consists of the serial, serialirr, and serialirr_onwrite
// methods, which all need no global state (except what is already provided
// by the serial mode implementation).
struct serial_mg : public method_group
{
virtual void init() { }
virtual void fini() { }
};
static serial_mg o_serial_mg;
class serialirr_dispatch : public abi_dispatch
{
public:
serialirr_dispatch() : abi_dispatch(false, true, true, false, &o_serial_mg)
{ }
protected:
serialirr_dispatch(bool ro, bool wt, bool uninstrumented,
bool closed_nesting, method_group* mg) :
abi_dispatch(ro, wt, uninstrumented, closed_nesting, mg) { }
// Transactional loads and stores simply access memory directly.
// These methods are static to avoid indirect calls, and will be used by the
// virtual ABI dispatch methods or by static direct-access methods created
// below.
template <typename V> static V load(const V* addr, ls_modifier mod)
{
return *addr;
}
template <typename V> static void store(V* addr, const V value,
ls_modifier mod)
{
*addr = value;
}
public:
static void memtransfer_static(void *dst, const void* src, size_t size,
bool may_overlap, ls_modifier dst_mod, ls_modifier src_mod)
{
if (!may_overlap)
::memcpy(dst, src, size);
else
::memmove(dst, src, size);
}
static void memset_static(void *dst, int c, size_t size, ls_modifier mod)
{
::memset(dst, c, size);
}
CREATE_DISPATCH_METHODS(virtual, )
CREATE_DISPATCH_METHODS_MEM()
virtual gtm_restart_reason begin_or_restart() { return NO_RESTART; }
virtual bool trycommit(gtm_word& priv_time) { return true; }
virtual void rollback(gtm_transaction_cp *cp) { abort(); }
virtual abi_dispatch* closed_nesting_alternative()
{
// For nested transactions with an instrumented code path, we can do
// undo logging.
return GTM::dispatch_serial();
}
};
class serial_dispatch : public abi_dispatch
{
protected:
static void log(const void *addr, size_t len)
{
gtm_thread *tx = gtm_thr();
tx->undolog.log(addr, len);
}
template <typename V> static V load(const V* addr, ls_modifier mod)
{
return *addr;
}
template <typename V> static void store(V* addr, const V value,
ls_modifier mod)
{
if (mod != WaW)
log(addr, sizeof(V));
*addr = value;
}
public:
static void memtransfer_static(void *dst, const void* src, size_t size,
bool may_overlap, ls_modifier dst_mod, ls_modifier src_mod)
{
if (dst_mod != WaW && dst_mod != NONTXNAL)
log(dst, size);
if (!may_overlap)
::memcpy(dst, src, size);
else
::memmove(dst, src, size);
}
static void memset_static(void *dst, int c, size_t size, ls_modifier mod)
{
if (mod != WaW)
log(dst, size);
::memset(dst, c, size);
}
virtual gtm_restart_reason begin_or_restart() { return NO_RESTART; }
virtual bool trycommit(gtm_word& priv_time) { return true; }
// Local undo will handle this.
// trydropreference() need not be changed either.
virtual void rollback(gtm_transaction_cp *cp) { }
CREATE_DISPATCH_METHODS(virtual, )
CREATE_DISPATCH_METHODS_MEM()
serial_dispatch() : abi_dispatch(false, true, false, true, &o_serial_mg) { }
};
// Like serialirr_dispatch but does not requests serial-irrevocable mode until
// the first write in the transaction. Can be useful for read-mostly workloads
// and testing, but is likely too simple to be of general purpose.
class serialirr_onwrite_dispatch : public serialirr_dispatch
{
public:
serialirr_onwrite_dispatch() :
serialirr_dispatch(false, true, false, false, &o_serial_mg) { }
protected:
static void pre_write()
{
gtm_thread *tx = gtm_thr();
if (!(tx->state & (gtm_thread::STATE_SERIAL
| gtm_thread::STATE_IRREVOCABLE)))
tx->serialirr_mode();
}
// Transactional loads access memory directly.
// Transactional stores switch to serial mode first.
template <typename V> static void store(V* addr, const V value,
ls_modifier mod)
{
pre_write();
serialirr_dispatch::store(addr, value, mod);
}
public:
static void memtransfer_static(void *dst, const void* src, size_t size,
bool may_overlap, ls_modifier dst_mod, ls_modifier src_mod)
{
pre_write();
serialirr_dispatch::memtransfer_static(dst, src, size, may_overlap,
dst_mod, src_mod);
}
static void memset_static(void *dst, int c, size_t size, ls_modifier mod)
{
pre_write();
serialirr_dispatch::memset_static(dst, c, size, mod);
}
CREATE_DISPATCH_METHODS(virtual, )
CREATE_DISPATCH_METHODS_MEM()
virtual void rollback(gtm_transaction_cp *cp)
{
gtm_thread *tx = gtm_thr();
if (tx->state & gtm_thread::STATE_IRREVOCABLE)
abort();
}
};
} // anon namespace
static const serialirr_dispatch o_serialirr_dispatch;
static const serial_dispatch o_serial_dispatch;
static const serialirr_onwrite_dispatch o_serialirr_onwrite_dispatch;
abi_dispatch *
GTM::dispatch_serialirr ()
{
return const_cast<serialirr_dispatch *>(&o_serialirr_dispatch);
}
abi_dispatch *
GTM::dispatch_serial ()
{
return const_cast<serial_dispatch *>(&o_serial_dispatch);
}
abi_dispatch *
GTM::dispatch_serialirr_onwrite ()
{
return
const_cast<serialirr_onwrite_dispatch *>(&o_serialirr_onwrite_dispatch);
}
// Put the transaction into serial-irrevocable mode.
void
GTM::gtm_thread::serialirr_mode ()
{
struct abi_dispatch *disp = abi_disp ();
if (this->state & STATE_SERIAL)
{
if (this->state & STATE_IRREVOCABLE)
return;
// Try to commit the dispatch-specific part of the transaction, as we
// would do for an outermost commit.
// We're already serial, so we don't need to ensure privatization safety
// for other transactions here.
gtm_word priv_time = 0;
bool ok = disp->trycommit (priv_time);
// Given that we're already serial, the trycommit better work.
assert (ok);
}
else if (serial_lock.write_upgrade (this))
{
this->state |= STATE_SERIAL;
// Try to commit the dispatch-specific part of the transaction, as we
// would do for an outermost commit.
// We have successfully upgraded to serial mode, so we don't need to
// ensure privatization safety for other transactions here.
// However, we are still a reader (wrt. privatization safety) until we
// have either committed or restarted, so finish the upgrade after that.
gtm_word priv_time = 0;
if (!disp->trycommit (priv_time))
restart (RESTART_SERIAL_IRR, true);
gtm_thread::serial_lock.write_upgrade_finish(this);
}
else
restart (RESTART_SERIAL_IRR, false);
this->state |= (STATE_SERIAL | STATE_IRREVOCABLE);
set_abi_disp (dispatch_serialirr ());
}
void ITM_REGPARM
_ITM_changeTransactionMode (_ITM_transactionState state)
{
assert (state == modeSerialIrrevocable);
gtm_thr()->serialirr_mode ();
}
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