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      1 /*
      2  * Copyright (C) 2015 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_CLASS_TABLE_INL_H_
     18 #define ART_RUNTIME_CLASS_TABLE_INL_H_
     19 
     20 #include "class_table.h"
     21 
     22 #include "gc_root-inl.h"
     23 #include "oat_file.h"
     24 
     25 namespace art {
     26 
     27 template<class Visitor>
     28 void ClassTable::VisitRoots(Visitor& visitor) {
     29   ReaderMutexLock mu(Thread::Current(), lock_);
     30   for (ClassSet& class_set : classes_) {
     31     for (TableSlot& table_slot : class_set) {
     32       table_slot.VisitRoot(visitor);
     33     }
     34   }
     35   for (GcRoot<mirror::Object>& root : strong_roots_) {
     36     visitor.VisitRoot(root.AddressWithoutBarrier());
     37   }
     38   for (const OatFile* oat_file : oat_files_) {
     39     for (GcRoot<mirror::Object>& root : oat_file->GetBssGcRoots()) {
     40       visitor.VisitRootIfNonNull(root.AddressWithoutBarrier());
     41     }
     42   }
     43 }
     44 
     45 template<class Visitor>
     46 void ClassTable::VisitRoots(const Visitor& visitor) {
     47   ReaderMutexLock mu(Thread::Current(), lock_);
     48   for (ClassSet& class_set : classes_) {
     49     for (TableSlot& table_slot : class_set) {
     50       table_slot.VisitRoot(visitor);
     51     }
     52   }
     53   for (GcRoot<mirror::Object>& root : strong_roots_) {
     54     visitor.VisitRoot(root.AddressWithoutBarrier());
     55   }
     56   for (const OatFile* oat_file : oat_files_) {
     57     for (GcRoot<mirror::Object>& root : oat_file->GetBssGcRoots()) {
     58       visitor.VisitRootIfNonNull(root.AddressWithoutBarrier());
     59     }
     60   }
     61 }
     62 
     63 template <typename Visitor, ReadBarrierOption kReadBarrierOption>
     64 bool ClassTable::Visit(Visitor& visitor) {
     65   ReaderMutexLock mu(Thread::Current(), lock_);
     66   for (ClassSet& class_set : classes_) {
     67     for (TableSlot& table_slot : class_set) {
     68       if (!visitor(table_slot.Read<kReadBarrierOption>())) {
     69         return false;
     70       }
     71     }
     72   }
     73   return true;
     74 }
     75 
     76 template <typename Visitor, ReadBarrierOption kReadBarrierOption>
     77 bool ClassTable::Visit(const Visitor& visitor) {
     78   ReaderMutexLock mu(Thread::Current(), lock_);
     79   for (ClassSet& class_set : classes_) {
     80     for (TableSlot& table_slot : class_set) {
     81       if (!visitor(table_slot.Read<kReadBarrierOption>())) {
     82         return false;
     83       }
     84     }
     85   }
     86   return true;
     87 }
     88 
     89 template<ReadBarrierOption kReadBarrierOption>
     90 inline mirror::Class* ClassTable::TableSlot::Read() const {
     91   const uint32_t before = data_.LoadRelaxed();
     92   ObjPtr<mirror::Class> const before_ptr(ExtractPtr(before));
     93   ObjPtr<mirror::Class> const after_ptr(
     94       GcRoot<mirror::Class>(before_ptr).Read<kReadBarrierOption>());
     95   if (kReadBarrierOption != kWithoutReadBarrier && before_ptr != after_ptr) {
     96     // If another thread raced and updated the reference, do not store the read barrier updated
     97     // one.
     98     data_.CompareAndSetStrongRelease(before, Encode(after_ptr, MaskHash(before)));
     99   }
    100   return after_ptr.Ptr();
    101 }
    102 
    103 template<typename Visitor>
    104 inline void ClassTable::TableSlot::VisitRoot(const Visitor& visitor) const {
    105   const uint32_t before = data_.LoadRelaxed();
    106   ObjPtr<mirror::Class> before_ptr(ExtractPtr(before));
    107   GcRoot<mirror::Class> root(before_ptr);
    108   visitor.VisitRoot(root.AddressWithoutBarrier());
    109   ObjPtr<mirror::Class> after_ptr(root.Read<kWithoutReadBarrier>());
    110   if (before_ptr != after_ptr) {
    111     // If another thread raced and updated the reference, do not store the read barrier updated
    112     // one.
    113     data_.CompareAndSetStrongRelease(before, Encode(after_ptr, MaskHash(before)));
    114   }
    115 }
    116 
    117 inline ObjPtr<mirror::Class> ClassTable::TableSlot::ExtractPtr(uint32_t data) {
    118   return reinterpret_cast<mirror::Class*>(data & ~kHashMask);
    119 }
    120 
    121 inline uint32_t ClassTable::TableSlot::Encode(ObjPtr<mirror::Class> klass, uint32_t hash_bits) {
    122   DCHECK_LE(hash_bits, kHashMask);
    123   return reinterpret_cast<uintptr_t>(klass.Ptr()) | hash_bits;
    124 }
    125 
    126 inline ClassTable::TableSlot::TableSlot(ObjPtr<mirror::Class> klass, uint32_t descriptor_hash)
    127     : data_(Encode(klass, MaskHash(descriptor_hash))) {
    128   if (kIsDebugBuild) {
    129     std::string temp;
    130     const uint32_t hash = ComputeModifiedUtf8Hash(klass->GetDescriptor(&temp));
    131     CHECK_EQ(descriptor_hash, hash);
    132   }
    133 }
    134 
    135 template <typename Filter>
    136 inline void ClassTable::RemoveStrongRoots(const Filter& filter) {
    137   WriterMutexLock mu(Thread::Current(), lock_);
    138   strong_roots_.erase(std::remove_if(strong_roots_.begin(), strong_roots_.end(), filter),
    139                       strong_roots_.end());
    140 }
    141 
    142 }  // namespace art
    143 
    144 #endif  // ART_RUNTIME_CLASS_TABLE_INL_H_
    145