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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_GC_ROOT_H_
#define ART_RUNTIME_GC_ROOT_H_
#include "base/macros.h"
#include "base/mutex.h" // For Locks::mutator_lock_.
namespace art {
namespace mirror {
class Object;
} // namespace mirror
enum RootType {
kRootUnknown = 0,
kRootJNIGlobal,
kRootJNILocal,
kRootJavaFrame,
kRootNativeStack,
kRootStickyClass,
kRootThreadBlock,
kRootMonitorUsed,
kRootThreadObject,
kRootInternedString,
kRootDebugger,
kRootVMInternal,
kRootJNIMonitor,
};
std::ostream& operator<<(std::ostream& os, const RootType& root_type);
class RootInfo {
public:
// Thread id 0 is for non thread roots.
explicit RootInfo(RootType type, uint32_t thread_id = 0)
: type_(type), thread_id_(thread_id) {
}
virtual ~RootInfo() {
}
RootType GetType() const {
return type_;
}
uint32_t GetThreadId() const {
return thread_id_;
}
virtual void Describe(std::ostream& os) const {
os << "Type=" << type_ << " thread_id=" << thread_id_;
}
private:
const RootType type_;
const uint32_t thread_id_;
};
// Returns the new address of the object, returns root if it has not moved. tid and root_type are
// only used by hprof.
typedef void (RootCallback)(mirror::Object** root, void* arg, const RootInfo& root_info);
template<class MirrorType>
class PACKED(4) GcRoot {
public:
template<ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
ALWAYS_INLINE MirrorType* Read() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void VisitRoot(RootCallback* callback, void* arg, const RootInfo& info) const {
DCHECK(!IsNull());
callback(reinterpret_cast<mirror::Object**>(&root_), arg, info);
DCHECK(!IsNull());
}
void VisitRootIfNonNull(RootCallback* callback, void* arg, const RootInfo& info) const {
if (!IsNull()) {
VisitRoot(callback, arg, info);
}
}
// This is only used by IrtIterator.
ALWAYS_INLINE MirrorType** AddressWithoutBarrier() {
return &root_;
}
bool IsNull() const {
// It's safe to null-check it without a read barrier.
return root_ == nullptr;
}
ALWAYS_INLINE explicit GcRoot<MirrorType>() : root_(nullptr) {
}
ALWAYS_INLINE explicit GcRoot<MirrorType>(MirrorType* ref)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) : root_(ref) {
}
private:
mutable MirrorType* root_;
};
} // namespace art
#endif // ART_RUNTIME_GC_ROOT_H_