/*
 * Copyright (c) 2001, 2016, 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.hpp"
#include "gc/g1/g1BSCodeGen.hpp"
#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/c1G1BSCodeGen.hpp"
#include "gc/g1/c2G1BSCodeGen.hpp"
#include "gc/g1/heapRegion.hpp"
#include "gc/g1/satbMarkQueue.hpp"
#include "logging/log.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/interfaceSupport.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/safepoint.hpp"
#include "runtime/thread.inline.hpp"

// Set of all SATB queues.
static SATBMarkQueueSet _satb_mark_queue_set;
// Set of all dirty card queues.
static DirtyCardQueueSet _dirty_card_queue_set;

// SATB marking queue support
SATBMarkQueueSet& G1BarrierSet::satb_mark_queue_set() {
  return _satb_mark_queue_set;
}

// Dirty card queue support
DirtyCardQueueSet& G1BarrierSet::dirty_card_queue_set() {
  return _dirty_card_queue_set;
}

G1BarrierSet::G1BarrierSet(CardTable* card_table) :
  CardTableModRefBS(card_table, BarrierSet::FakeRtti(BarrierSet::G1BarrierSet))
{ }

void G1BarrierSet::satb_enqueue(oop pre_val) {
  // Nulls should have been already filtered.
  assert(pre_val->is_oop(true), "Error");

  if (!_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);
    _satb_mark_queue_set.shared_satb_queue()->enqueue(pre_val);
  }
}

void G1BarrierSet::card_enqueue(volatile jbyte* card) {
  Thread* thr = Thread::current();
  if (thr->is_Java_thread()) {
    JavaThread* jt = (JavaThread*)thr;
    jt->dirty_card_queue().enqueue(card);
  } else {
    MutexLockerEx x(Shared_DirtyCardQ_lock,
                    Mutex::_no_safepoint_check_flag);
    dirty_card_queue_set().shared_dirty_card_queue()->enqueue(card);
  }
}

BarrierSetCodeGen *G1BarrierSet::make_code_gen() {
  return new G1BSCodeGen();
}

C1BarrierSetCodeGen* G1BarrierSet::make_c1_code_gen() {
  return new C1G1BSCodeGen();
}

C2BarrierSetCodeGen* G1BarrierSet::make_c2_code_gen() {
  return new C2G1BSCodeGen();
}

template <class T> void
G1BarrierSet::write_ref_array_pre_work(T* dst, int count) {
  if (!_satb_mark_queue_set.is_active()) return;
  T* elem_ptr = dst;
  for (int i = 0; i < count; i++, elem_ptr++) {
    T heap_oop = oopDesc::load_heap_oop(elem_ptr);
    if (!oopDesc::is_null(heap_oop)) {
      satb_enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
    }
  }
}

void G1BarrierSet::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
  if (!dest_uninitialized) {
    write_ref_array_pre_work(dst, count);
  }
}

void G1BarrierSet::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
  if (!dest_uninitialized) {
    write_ref_array_pre_work(dst, count);
  }
}

void G1BarrierSet::invalidate(MemRegion mr) {
  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();
          _dirty_card_queue_set.shared_dirty_card_queue()->enqueue(byte);
        }
      }
    }
  }
}

void G1BarrierSet::write_ref_nmethod_post(nmethod* nm, oop obj) {
  if (obj != NULL) {
    G1CollectedHeap* g1h = G1CollectedHeap::heap();
    HeapRegion* hr = g1h->heap_region_containing(obj);
    hr->add_strong_code_root(nm);
  }
}

class G1EnsureLastRefToRegion : public OopClosure {
  G1CollectedHeap* _g1h;
  HeapRegion* _hr;
  oop* _dst;

  bool _value;
public:
  G1EnsureLastRefToRegion(G1CollectedHeap* g1h, HeapRegion* hr, oop* dst) :
    _g1h(g1h), _hr(hr), _dst(dst), _value(true) {}

  void do_oop(oop* p) {
    if (_value && p != _dst) {
      oop obj = oopDesc::load_heap_oop(p);
      if (obj != NULL) {
        HeapRegion* hr = _g1h->heap_region_containing(obj);
        if (hr == _hr) {
          // Another reference to the same region.
          _value = false;
        }
      }
    }
  }
  void do_oop(narrowOop* p) { ShouldNotReachHere(); }
  bool value() const        { return _value;  }
};

void G1BarrierSet::write_ref_nmethod_pre(nmethod* nm, ptrdiff_t offset) {
  oop* dst = (oop*)(intptr_t(nm) + offset);
  oop obj = oopDesc::load_heap_oop(dst);
  if (obj != NULL) {
    G1CollectedHeap* g1h = G1CollectedHeap::heap();
    HeapRegion* hr = g1h->heap_region_containing(obj);
    G1EnsureLastRefToRegion ensure_last_ref(g1h, hr, dst);
    nm->oops_do(&ensure_last_ref);
    if (ensure_last_ref.value()) {
      // Last reference to this region, remove the nmethod from the rset.
      hr->remove_strong_code_root(nm);
    }
  }
}

void G1BarrierSet::on_add_thread(JavaThread* thread) {
  assert(!SafepointSynchronize::is_at_safepoint(),
         "we should not be at a safepoint");

  SATBMarkQueue& satb_queue = thread->satb_mark_queue();
  SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
  // The SATB queue should have been constructed with its active
  // field set to false.
  assert(!satb_queue.is_active(), "SATB queue should not be active");
  assert(satb_queue.is_empty(), "SATB queue should be empty");
  // If we are creating the thread during a marking cycle, we should
  // set the active field of the SATB queue to true.
  if (satb_queue_set.is_active()) {
    satb_queue.set_active(true);
  }

  DirtyCardQueue& dirty_queue = thread->dirty_card_queue();
  // The dirty card queue should have been constructed with its
  // active field set to true.
  assert(dirty_queue.is_active(), "dirty card queue should be active");
}

void G1BarrierSet::on_destroy_thread(JavaThread* thread) {
  CardTableModRefBS::on_destroy_thread(thread);
  thread->satb_mark_queue().flush();
  thread->dirty_card_queue().flush();
}

bool G1BarrierSet::is_referent_field(oop base, ptrdiff_t offset) {
  Klass* k;
  return offset == java_lang_ref_Reference::referent_offset &&
    (k = base->klass()) &&
    InstanceKlass::cast(k)->reference_type() != REF_NONE;
}

// G1 write-barrier pre: executed before a pointer store.
JRT_LEAF(void, G1BarrierSet::g1_wb_pre(oopDesc* orig, JavaThread *thread))
  if (orig == NULL) {
    assert(false, "should be optimized out");
    return;
  }
  assert(orig->is_oop(true /* ignore mark word */), "Error");
  // store the original value that was in the field reference
  thread->satb_mark_queue().enqueue(orig);
JRT_END

// G1 write-barrier post: executed after a pointer store.
JRT_LEAF(void, G1BarrierSet::g1_wb_post(void* card_addr, JavaThread* thread))
  thread->dirty_card_queue().enqueue(card_addr);
JRT_END