1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_RUNTIME_GC_ROOT_H_ 18 #define ART_RUNTIME_GC_ROOT_H_ 19 20 #include "base/macros.h" 21 #include "base/mutex.h" // For Locks::mutator_lock_. 22 #include "object_callbacks.h" 23 24 namespace art { 25 26 template<class MirrorType> 27 class PACKED(4) GcRoot { 28 public: 29 template<ReadBarrierOption kReadBarrierOption = kWithReadBarrier> 30 ALWAYS_INLINE MirrorType* Read() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); 31 ALWAYS_INLINE void Assign(MirrorType* value) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); 32 VisitRoot(RootCallback * callback,void * arg,uint32_t thread_id,RootType root_type)33 void VisitRoot(RootCallback* callback, void* arg, uint32_t thread_id, RootType root_type) { 34 callback(reinterpret_cast<mirror::Object**>(&root_), arg, thread_id, root_type); 35 } 36 37 // This is only used by IrtIterator. AddressWithoutBarrier()38 ALWAYS_INLINE MirrorType** AddressWithoutBarrier() { 39 return &root_; 40 } 41 IsNull()42 bool IsNull() const { 43 // It's safe to null-check it without a read barrier. 44 return root_ == nullptr; 45 } 46 root_(nullptr)47 ALWAYS_INLINE explicit GcRoot<MirrorType>() : root_(nullptr) { 48 } 49 50 ALWAYS_INLINE explicit GcRoot<MirrorType>(MirrorType* ref) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)51 SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) : root_(ref) { 52 } 53 54 private: 55 MirrorType* root_; 56 }; 57 58 } // namespace art 59 60 #endif // ART_RUNTIME_GC_ROOT_H_ 61