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1 /**
2  * Copyright (c) 2021-2022 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef LIBPANDAFILE_PANDA_CACHE_H
17 #define LIBPANDAFILE_PANDA_CACHE_H
18 
19 #include "file.h"
20 #include "os/mutex.h"
21 #include "libpandabase/utils/math_helpers.h"
22 
23 #include <atomic>
24 #include <vector>
25 
26 namespace panda {
27 
28 class Method;
29 class Field;
30 class Class;
31 
32 namespace panda_file {
33 
34 // NOLINTNEXTLINE(cppcoreguidelines-special-member-functions, hicpp-special-member-functions)
35 class PandaCache {
36 public:
37     struct MethodCachePair {
38         File::EntityId id_;
39         Method *ptr_ {nullptr};
40     };
41 
42     struct FieldCachePair {
43         File::EntityId id_;
44         Field *ptr_ {nullptr};
45     };
46 
47     struct ClassCachePair {
48         File::EntityId id_;
49         Class *ptr_ {nullptr};
50     };
51 
PandaCache()52     PandaCache()
53         : METHOD_CACHE_SIZE(DEFAULT_METHOD_CACHE_SIZE),
54           FIELD_CACHE_SIZE(DEFAULT_FIELD_CACHE_SIZE),
55           CLASS_CACHE_SIZE(DEFAULT_CLASS_CACHE_SIZE)
56     {
57         method_cache_.resize(METHOD_CACHE_SIZE, MethodCachePair());
58         field_cache_.resize(FIELD_CACHE_SIZE, FieldCachePair());
59         class_cache_.resize(CLASS_CACHE_SIZE, ClassCachePair());
60     }
61 
62     ~PandaCache() = default;
63 
GetMethodIndex(File::EntityId id)64     inline uint32_t GetMethodIndex(File::EntityId id) const
65     {
66         return panda::helpers::math::PowerOfTwoTableSlot(id.GetOffset(), METHOD_CACHE_SIZE);
67     }
68 
GetFieldIndex(File::EntityId id)69     inline uint32_t GetFieldIndex(File::EntityId id) const
70     {
71         // lowest one or two bits is very likely same between different fields
72         return panda::helpers::math::PowerOfTwoTableSlot(id.GetOffset(), FIELD_CACHE_SIZE, 2U);
73     }
74 
GetClassIndex(File::EntityId id)75     inline uint32_t GetClassIndex(File::EntityId id) const
76     {
77         return panda::helpers::math::PowerOfTwoTableSlot(id.GetOffset(), CLASS_CACHE_SIZE);
78     }
79 
GetMethodFromCache(File::EntityId id)80     inline Method *GetMethodFromCache(File::EntityId id) const
81     {
82         uint32_t index = GetMethodIndex(id);
83         auto *pair_ptr =
84             reinterpret_cast<std::atomic<MethodCachePair> *>(reinterpret_cast<uintptr_t>(&(method_cache_[index])));
85         // Atomic with acquire order reason: fixes a data race with method_cache_
86         auto pair = pair_ptr->load(std::memory_order_acquire);
87         TSAN_ANNOTATE_HAPPENS_AFTER(pair_ptr);
88         if (pair.id_ == id) {
89             return pair.ptr_;
90         }
91         return nullptr;
92     }
93 
SetMethodCache(File::EntityId id,Method * method)94     inline void SetMethodCache(File::EntityId id, Method *method)
95     {
96         MethodCachePair pair;
97         pair.id_ = id;
98         pair.ptr_ = method;
99         uint32_t index = GetMethodIndex(id);
100         auto *pair_ptr =
101             reinterpret_cast<std::atomic<MethodCachePair> *>(reinterpret_cast<uintptr_t>(&(method_cache_[index])));
102         TSAN_ANNOTATE_HAPPENS_BEFORE(pair_ptr);
103         // Atomic with release order reason: fixes a data race with method_cache_
104         pair_ptr->store(pair, std::memory_order_release);
105     }
106 
GetFieldFromCache(File::EntityId id)107     inline Field *GetFieldFromCache(File::EntityId id) const
108     {
109         uint32_t index = GetFieldIndex(id);
110         auto *pair_ptr =
111             reinterpret_cast<std::atomic<FieldCachePair> *>(reinterpret_cast<uintptr_t>(&(field_cache_[index])));
112         // Atomic with acquire order reason: fixes a data race with field_cache_
113         auto pair = pair_ptr->load(std::memory_order_acquire);
114         TSAN_ANNOTATE_HAPPENS_AFTER(pair_ptr);
115         if (pair.id_ == id) {
116             return pair.ptr_;
117         }
118         return nullptr;
119     }
120 
SetFieldCache(File::EntityId id,Field * field)121     inline void SetFieldCache(File::EntityId id, Field *field)
122     {
123         uint32_t index = GetFieldIndex(id);
124         auto *pair_ptr =
125             reinterpret_cast<std::atomic<FieldCachePair> *>(reinterpret_cast<uintptr_t>(&(field_cache_[index])));
126         FieldCachePair pair;
127         pair.id_ = id;
128         pair.ptr_ = field;
129         TSAN_ANNOTATE_HAPPENS_BEFORE(pair_ptr);
130         // Atomic with release order reason: fixes a data race with field_cache_
131         pair_ptr->store(pair, std::memory_order_release);
132     }
133 
GetClassFromCache(File::EntityId id)134     inline Class *GetClassFromCache(File::EntityId id) const
135     {
136         uint32_t index = GetClassIndex(id);
137         auto *pair_ptr =
138             reinterpret_cast<std::atomic<ClassCachePair> *>(reinterpret_cast<uintptr_t>(&(class_cache_[index])));
139         // Atomic with acquire order reason: fixes a data race with class_cache_
140         auto pair = pair_ptr->load(std::memory_order_acquire);
141         TSAN_ANNOTATE_HAPPENS_AFTER(pair_ptr);
142         if (pair.id_ == id) {
143             return pair.ptr_;
144         }
145         return nullptr;
146     }
147 
SetClassCache(File::EntityId id,Class * clazz)148     inline void SetClassCache(File::EntityId id, Class *clazz)
149     {
150         ClassCachePair pair;
151         pair.id_ = id;
152         pair.ptr_ = clazz;
153         uint32_t index = GetClassIndex(id);
154         auto *pair_ptr =
155             reinterpret_cast<std::atomic<ClassCachePair> *>(reinterpret_cast<uintptr_t>(&(class_cache_[index])));
156         TSAN_ANNOTATE_HAPPENS_BEFORE(pair_ptr);
157         // Atomic with release order reason: fixes a data race with class_cache_
158         pair_ptr->store(pair, std::memory_order_release);
159     }
160 
Clear()161     inline void Clear()
162     {
163         method_cache_.clear();
164         field_cache_.clear();
165         class_cache_.clear();
166 
167         method_cache_.resize(METHOD_CACHE_SIZE, MethodCachePair());
168         field_cache_.resize(FIELD_CACHE_SIZE, FieldCachePair());
169         class_cache_.resize(CLASS_CACHE_SIZE, ClassCachePair());
170     }
171 
172     template <class Callback>
EnumerateCachedClasses(const Callback & cb)173     bool EnumerateCachedClasses(const Callback &cb)
174     {
175         for (uint32_t i = 0; i < CLASS_CACHE_SIZE; i++) {
176             auto *pair_ptr =
177                 reinterpret_cast<std::atomic<ClassCachePair> *>(reinterpret_cast<uintptr_t>(&(class_cache_[i])));
178             // Atomic with acquire order reason: fixes a data race with class_cache_
179             auto pair = pair_ptr->load(std::memory_order_acquire);
180             TSAN_ANNOTATE_HAPPENS_AFTER(pair_ptr);
181             if (pair.ptr_ != nullptr) {
182                 if (!cb(pair.ptr_)) {
183                     return false;
184                 }
185             }
186         }
187         return true;
188     }
189 
190 private:
191     static constexpr uint32_t DEFAULT_FIELD_CACHE_SIZE = 1024U;
192     static constexpr uint32_t DEFAULT_METHOD_CACHE_SIZE = 1024U;
193     static constexpr uint32_t DEFAULT_CLASS_CACHE_SIZE = 1024U;
194     static_assert(panda::helpers::math::IsPowerOfTwo(DEFAULT_FIELD_CACHE_SIZE));
195     static_assert(panda::helpers::math::IsPowerOfTwo(DEFAULT_METHOD_CACHE_SIZE));
196     static_assert(panda::helpers::math::IsPowerOfTwo(DEFAULT_CLASS_CACHE_SIZE));
197 
198     const uint32_t METHOD_CACHE_SIZE;
199     const uint32_t FIELD_CACHE_SIZE;
200     const uint32_t CLASS_CACHE_SIZE;
201 
202     std::vector<MethodCachePair> method_cache_;
203     std::vector<FieldCachePair> field_cache_;
204     std::vector<ClassCachePair> class_cache_;
205 };
206 
207 }  // namespace panda_file
208 }  // namespace panda
209 
210 #endif  // LIBPANDAFILE_PANDA_CACHE_H
211