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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_RUNTIME_MONITOR_POOL_H_
#define ART_RUNTIME_MONITOR_POOL_H_
#include "monitor.h"
#include "safe_map.h"
#include <stdint.h>
namespace art {
// Abstraction to keep monitors small enough to fit in a lock word (32bits). On 32bit systems the
// monitor id loses the alignment bits of the Monitor*.
class MonitorPool {
public:
static MonitorPool* Create() {
#ifndef __LP64__
return nullptr;
#else
return new MonitorPool();
#endif
}
static Monitor* MonitorFromMonitorId(MonitorId mon_id) {
#ifndef __LP64__
return reinterpret_cast<Monitor*>(mon_id << 3);
#else
return Runtime::Current()->GetMonitorPool()->LookupMonitorFromTable(mon_id);
#endif
}
static MonitorId MonitorIdFromMonitor(Monitor* mon) {
#ifndef __LP64__
return reinterpret_cast<MonitorId>(mon) >> 3;
#else
return mon->GetMonitorId();
#endif
}
static MonitorId CreateMonitorId(Thread* self, Monitor* mon) {
#ifndef __LP64__
UNUSED(self);
return MonitorIdFromMonitor(mon);
#else
return Runtime::Current()->GetMonitorPool()->AllocMonitorIdFromTable(self, mon);
#endif
}
static void ReleaseMonitorId(MonitorId mon_id) {
#ifndef __LP64__
UNUSED(mon_id);
#else
Runtime::Current()->GetMonitorPool()->ReleaseMonitorIdFromTable(mon_id);
#endif
}
private:
#ifdef __LP64__
MonitorPool();
Monitor* LookupMonitorFromTable(MonitorId mon_id);
MonitorId LookupMonitorIdFromTable(Monitor* mon);
MonitorId AllocMonitorIdFromTable(Thread* self, Monitor* mon);
void ReleaseMonitorIdFromTable(MonitorId mon_id);
ReaderWriterMutex allocated_ids_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
static constexpr uint32_t kMaxMonitorId = 0xFFFF;
std::bitset<kMaxMonitorId> allocated_ids_ GUARDED_BY(allocated_ids_lock_);
SafeMap<MonitorId, Monitor*> table_ GUARDED_BY(allocated_ids_lock_);
#endif
};
} // namespace art
#endif // ART_RUNTIME_MONITOR_POOL_H_