/*
 * Copyright (c) 1998, 2019, 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
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 */

#ifndef SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP
#define SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP

#include "logging/log.hpp"
#include "runtime/atomic.hpp"

inline intptr_t ObjectMonitor::is_entered(TRAPS) const {
  if (THREAD == _owner || THREAD->is_lock_owned((address) _owner)) {
    return 1;
  }
  return 0;
}

inline markWord ObjectMonitor::header() const {
  return Atomic::load(&_header);
}

inline volatile markWord* ObjectMonitor::header_addr() {
  assert((intptr_t)this == (intptr_t)&_header, "sync code expects this");
  return &_header;
}

inline void ObjectMonitor::set_header(markWord hdr) {
  Atomic::store(hdr, &_header);
}

inline jint ObjectMonitor::waiters() const {
  return _waiters;
}

// Returns NULL if DEFLATER_MARKER is observed.
inline void* ObjectMonitor::owner() const {
  void* owner = _owner;
  return owner != DEFLATER_MARKER ? owner : NULL;
}

// Returns true if owner field == DEFLATER_MARKER and false otherwise.
// This accessor is called when we really need to know if the owner
// field == DEFLATER_MARKER and any non-NULL value won't do the trick.
inline bool ObjectMonitor::owner_is_DEFLATER_MARKER() {
  return OrderAccess::load_acquire(&_owner) == DEFLATER_MARKER;
}

inline void ObjectMonitor::clear() {
  assert(Atomic::load(&_header).value() != 0, "must be non-zero");
  assert(_owner == NULL, "must be NULL: owner=" INTPTR_FORMAT, p2i(_owner));
  assert(ref_count() == 0, "must be 0: ref_count=%d", ref_count());

  Atomic::store(markWord::zero(), &_header);

  clear_using_JT();
}

inline void ObjectMonitor::clear_using_JT() {
  // Unlike other *_using_JT() functions, we cannot assert
  // AsyncDeflateIdleMonitors or Thread::current()->is_Java_thread()
  // because clear() calls this function for the rest of its checks.

  if (AsyncDeflateIdleMonitors) {
    // Async deflation protocol uses the header, owner and ref_count
    // fields. While the ObjectMonitor being deflated is on the global free
    // list, we leave those three fields alone; owner == DEFLATER_MARKER
    // and ref_count < 0 will force any racing threads to retry. The
    // header field is used by install_displaced_markword_in_object()
    // in the last part of the deflation protocol so we cannot check
    // its value here.
    guarantee(_owner == NULL || _owner == DEFLATER_MARKER,
              "must be NULL or DEFLATER_MARKER: owner=" INTPTR_FORMAT,
              p2i(_owner));
    guarantee(ref_count() <= 0, "must be <= 0: ref_count=%d", ref_count());
  }
  assert(_contentions == 0, "must be 0: contentions=%d", _contentions);
  assert(_waiters == 0, "must be 0: waiters=%d", _waiters);
  assert(_recursions == 0, "must be 0: recursions=" INTX_FORMAT, _recursions);
  assert(_object != NULL, "must be non-NULL");
 
  set_allocation_state(Free);
  _object = NULL;
}

inline void* ObjectMonitor::object() const {
  return _object;
}

inline void* ObjectMonitor::object_addr() {
  return (void *)(&_object);
}

inline void ObjectMonitor::set_object(void* obj) {
  _object = obj;
}

// return number of threads contending for this monitor
inline jint ObjectMonitor::contentions() const {
  return _contentions;
}

// Set _owner field to new_value; current value must match old_value.
inline void ObjectMonitor::set_owner_from(void* new_value, void* old_value) {
  void* prev = Atomic::cmpxchg(new_value, &_owner, old_value);
  ADIM_guarantee(prev == old_value, "unexpected prev owner=" INTPTR_FORMAT
                 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(old_value));
  log_trace(monitorinflation, owner)("mid=" INTPTR_FORMAT ", prev="
                                     INTPTR_FORMAT ", new=" INTPTR_FORMAT,
                                     p2i(this), p2i(prev), p2i(new_value));
}

// Set _owner field to new_value; current value must match old_value1 or old_value2.
inline void ObjectMonitor::set_owner_from(void* new_value, void* old_value1, void* old_value2) {
  void* prev = Atomic::cmpxchg(new_value, &_owner, old_value1);
  if (prev != old_value1) {
    prev = Atomic::cmpxchg(new_value, &_owner, old_value2);
  }
  ADIM_guarantee(prev == old_value1 || prev == old_value2,
                 "unexpected prev owner=" INTPTR_FORMAT ", expected1="
                 INTPTR_FORMAT " or expected2=" INTPTR_FORMAT, p2i(prev),
                 p2i(old_value1), p2i(old_value2));
  log_trace(monitorinflation, owner)("mid=" INTPTR_FORMAT ", prev="
                                     INTPTR_FORMAT ", new=" INTPTR_FORMAT,
                                     p2i(this), p2i(prev), p2i(new_value));
}

// Set _owner field to self; current value must match basic_lock_p.
inline void ObjectMonitor::set_owner_from_BasicLock(Thread* self, void* basic_lock_p) {
  assert(self->is_lock_owned((address)basic_lock_p), "self=" INTPTR_FORMAT
         " must own basic_lock_p=" INTPTR_FORMAT, p2i(self), p2i(basic_lock_p));
  void* prev = _owner;
  ADIM_guarantee(prev == basic_lock_p, "unexpected prev owner=" INTPTR_FORMAT
                 ", expected=" INTPTR_FORMAT, p2i(prev), p2i(basic_lock_p));
  // Non-null owner field to non-null owner field is safe without
  // cmpxchg() as long as all readers can tolerate either flavor.
  _owner = self;
  log_trace(monitorinflation, owner)("mid=" INTPTR_FORMAT ", prev="
                                     INTPTR_FORMAT ", new=" INTPTR_FORMAT,
                                     p2i(this), p2i(prev), p2i(self));
}

// Try to set _owner field to new_value if the current value matches
// old_value. Otherwise, does not change the _owner field.
inline void* ObjectMonitor::try_set_owner_from(void* new_value, void* old_value) {
  void* prev = Atomic::cmpxchg(new_value, &_owner, old_value);
  if (prev == old_value) {
    log_trace(monitorinflation, owner)("mid=" INTPTR_FORMAT ", prev="
                                       INTPTR_FORMAT ", new=" INTPTR_FORMAT,
                                       p2i(this), p2i(prev), p2i(new_value));
  }
  return prev;
}

inline void ObjectMonitor::set_allocation_state(ObjectMonitor::AllocationState s) {
  _allocation_state = s;
}

inline ObjectMonitor::AllocationState ObjectMonitor::allocation_state() const {
  return _allocation_state;
}

inline bool ObjectMonitor::is_free() const {
  return _allocation_state == Free;
}

inline bool ObjectMonitor::is_active() const {
  return !is_free();
}

inline bool ObjectMonitor::is_old() const {
  return _allocation_state == Old;
}

inline bool ObjectMonitor::is_new() const {
  return _allocation_state == New;
}

inline void ObjectMonitor::dec_ref_count() {
  // The decrement only needs to be MO_ACQ_REL since the reference
  // counter is volatile.
  Atomic::dec(&_ref_count);
  // Can be negative as part of async deflation protocol.
  ADIM_guarantee(AsyncDeflateIdleMonitors || ref_count() >= 0,
                 "sanity check: ref_count=%d", ref_count());
}

inline void ObjectMonitor::inc_ref_count() {
  // The increment needs to be MO_SEQ_CST so that the reference
  // counter update is seen as soon as possible in a race with the
  // async deflation protocol.
  Atomic::inc(&_ref_count);
  // Can be negative as part of async deflation protocol.
  ADIM_guarantee(AsyncDeflateIdleMonitors || ref_count() > 0,
                 "sanity check: ref_count=%d", ref_count());
}

inline jint ObjectMonitor::ref_count() const {
  return OrderAccess::load_acquire(&_ref_count);
}

#endif // SHARE_RUNTIME_OBJECTMONITOR_INLINE_HPP