/*

 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "gc/g1/g1BarrierSet.inline.hpp"

#include "gc/g1/g1BarrierSetAssembler.hpp"

#include "gc/g1/g1CardTable.inline.hpp"

#include "gc/g1/g1CollectedHeap.inline.hpp"

#include "gc/g1/heapRegion.hpp"

#include "gc/g1/satbMarkQueue.hpp"

#include "logging/log.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/thread.inline.hpp"

#include "utilities/macros.hpp"

G1BarrierSet::G1BarrierSet(G1CardTable* card_table) :

  CardTableBarrierSet(make_barrier_set_assembler<G1BarrierSetAssembler>(),

                      card_table,

                      BarrierSet::FakeRtti(BarrierSet::G1BarrierSet)),

  _dcqs(JavaThread::dirty_card_queue_set())

{ }

void G1BarrierSet::enqueue(oop pre_val) {

  // Nulls should have been already filtered.

  assert(oopDesc::is_oop(pre_val, true), "Error");

  if (!JavaThread::satb_mark_queue_set().is_active()) return;

  Thread* thr = Thread::current();

  if (thr->is_Java_thread()) {

    JavaThread* jt = (JavaThread*)thr;

    jt->satb_mark_queue().enqueue(pre_val);

  } else {

    MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);

    JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val);

  }

}

void G1BarrierSet::write_ref_array_pre_oop_entry(oop* dst, size_t length) {

  G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());

  bs->write_ref_array_pre(dst, length, false);

}

void G1BarrierSet::write_ref_array_pre_narrow_oop_entry(narrowOop* dst, size_t length) {

  G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());

  bs->write_ref_array_pre(dst, length, false);

}

void G1BarrierSet::write_ref_array_post_entry(HeapWord* dst, size_t length) {

  G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());

  bs->G1BarrierSet::write_ref_array(dst, length);

}

template <class T> void

G1BarrierSet::write_ref_array_pre_work(T* dst, size_t count) {

  if (!JavaThread::satb_mark_queue_set().is_active()) return;

  T* elem_ptr = dst;

  for (size_t i = 0; i < count; i++, elem_ptr++) {

    }

  }

}

void G1BarrierSet::write_ref_array_pre(oop* dst, size_t count, bool dest_uninitialized) {

  if (!dest_uninitialized) {

    write_ref_array_pre_work(dst, count);

  }

}

void G1BarrierSet::write_ref_array_pre(narrowOop* dst, size_t count, bool dest_uninitialized) {

  if (!dest_uninitialized) {

    write_ref_array_pre_work(dst, count);

  }

}

void G1BarrierSet::write_ref_field_post_slow(volatile jbyte* byte) {

  // In the slow path, we know a card is not young

  assert(*byte != G1CardTable::g1_young_card_val(), "slow path invoked without filtering");

  OrderAccess::storeload();

  if (*byte != G1CardTable::dirty_card_val()) {

    *byte = G1CardTable::dirty_card_val();

    Thread* thr = Thread::current();

    if (thr->is_Java_thread()) {

      JavaThread* jt = (JavaThread*)thr;

      jt->dirty_card_queue().enqueue(byte);

    } else {

      MutexLockerEx x(Shared_DirtyCardQ_lock,

                      Mutex::_no_safepoint_check_flag);

      _dcqs.shared_dirty_card_queue()->enqueue(byte);

    }

  }

}

void G1BarrierSet::invalidate(MemRegion mr) {

  if (mr.is_empty()) {

    return;

  }

  volatile jbyte* byte = _card_table->byte_for(mr.start());

  jbyte* last_byte = _card_table->byte_for(mr.last());

  Thread* thr = Thread::current();

    // skip all consecutive young cards

  for (; byte <= last_byte && *byte == G1CardTable::g1_young_card_val(); byte++);

  if (byte <= last_byte) {

    OrderAccess::storeload();

    // Enqueue if necessary.

    if (thr->is_Java_thread()) {

      JavaThread* jt = (JavaThread*)thr;

      for (; byte <= last_byte; byte++) {

        if (*byte == G1CardTable::g1_young_card_val()) {

          continue;

        }

        if (*byte != G1CardTable::dirty_card_val()) {

          *byte = G1CardTable::dirty_card_val();

          jt->dirty_card_queue().enqueue(byte);

        }

      }

    } else {

      MutexLockerEx x(Shared_DirtyCardQ_lock,

                      Mutex::_no_safepoint_check_flag);

      for (; byte <= last_byte; byte++) {

        if (*byte == G1CardTable::g1_young_card_val()) {

          continue;

        }

        if (*byte != G1CardTable::dirty_card_val()) {

          *byte = G1CardTable::dirty_card_val();

          _dcqs.shared_dirty_card_queue()->enqueue(byte);

        }

      }

    }

  }

}

void G1BarrierSet::on_thread_attach(JavaThread* thread) {

  // This method initializes the SATB and dirty card queues before a

  // JavaThread is added to the Java thread list. Right now, we don't

  // have to do anything to the dirty card queue (it should have been

  // activated when the thread was created), but we have to activate

  // the SATB queue if the thread is created while a marking cycle is

  // in progress. The activation / de-activation of the SATB queues at

  // the beginning / end of a marking cycle is done during safepoints

  // so we have to make sure this method is called outside one to be

  // able to safely read the active field of the SATB queue set. Right

  // now, it is called just before the thread is added to the Java

  // thread list in the Threads::add() method. That method is holding

  // the Threads_lock which ensures we are outside a safepoint. We

  // cannot do the obvious and set the active field of the SATB queue

  // when the thread is created given that, in some cases, safepoints

  // might happen between the JavaThread constructor being called and the

  // thread being added to the Java thread list (an example of this is

  // when the structure for the DestroyJavaVM thread is created).

  assert(!SafepointSynchronize::is_at_safepoint(), "We should not be at a safepoint");

  assert(!thread->satb_mark_queue().is_active(), "SATB queue should not be active");

  assert(thread->satb_mark_queue().is_empty(), "SATB queue should be empty");

  assert(thread->dirty_card_queue().is_active(), "Dirty card queue should be active");

  // If we are creating the thread during a marking cycle, we should

  // set the active field of the SATB queue to true.

  if (thread->satb_mark_queue_set().is_active()) {

    thread->satb_mark_queue().set_active(true);

  }

}

void G1BarrierSet::on_thread_detach(JavaThread* thread) {

  // Flush any deferred card marks, SATB buffers and dirty card queue buffers

  CardTableBarrierSet::on_thread_detach(thread);

  thread->satb_mark_queue().flush();

  thread->dirty_card_queue().flush();

}