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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>
VisitRoots(Visitor & 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>
VisitRoots(const Visitor & 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>
Visit(Visitor & visitor)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())) {
69         return false;
70       }
71     }
72   }
73   return true;
74 }
75 
76 template <typename Visitor>
Visit(const Visitor & visitor)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())) {
82         return false;
83       }
84     }
85   }
86   return true;
87 }
88 
89 template<ReadBarrierOption kReadBarrierOption>
Read()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_.CompareExchangeStrongRelease(before, Encode(after_ptr, MaskHash(before)));
99   }
100   return after_ptr.Ptr();
101 }
102 
103 template<typename Visitor>
VisitRoot(const Visitor & 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_.CompareExchangeStrongRelease(before, Encode(after_ptr, MaskHash(before)));
114   }
115 }
116 
ExtractPtr(uint32_t data)117 inline ObjPtr<mirror::Class> ClassTable::TableSlot::ExtractPtr(uint32_t data) {
118   return reinterpret_cast<mirror::Class*>(data & ~kHashMask);
119 }
120 
Encode(ObjPtr<mirror::Class> klass,uint32_t hash_bits)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 
TableSlot(ObjPtr<mirror::Class> klass,uint32_t descriptor_hash)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>
RemoveStrongRoots(const Filter & 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