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