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      1 /*
      2  * Copyright (C) 2016 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_COMPILER_UTILS_ATOMIC_DEX_REF_MAP_H_
     18 #define ART_COMPILER_UTILS_ATOMIC_DEX_REF_MAP_H_
     19 
     20 #include "base/dchecked_vector.h"
     21 #include "dex_file.h"
     22 #include "safe_map.h"
     23 
     24 namespace art {
     25 
     26 class DexFile;
     27 
     28 // Used by CompilerCallbacks to track verification information from the Runtime.
     29 template <typename T>
     30 class AtomicDexRefMap {
     31  public:
     32   explicit AtomicDexRefMap() {}
     33   ~AtomicDexRefMap() {}
     34 
     35   // Atomically swap the element in if the existing value matches expected.
     36   enum InsertResult {
     37     kInsertResultInvalidDexFile,
     38     kInsertResultCASFailure,
     39     kInsertResultSuccess,
     40   };
     41   InsertResult Insert(DexFileReference ref, const T& expected, const T& desired);
     42 
     43   // Retreive an item, returns false if the dex file is not added.
     44   bool Get(DexFileReference ref, T* out) const;
     45 
     46   // Dex files must be added before method references belonging to them can be used as keys. Not
     47   // thread safe.
     48   void AddDexFile(const DexFile* dex_file, size_t max_index);
     49 
     50   bool HaveDexFile(const DexFile* dex_file) const {
     51     return arrays_.find(dex_file) != arrays_.end();
     52   }
     53 
     54   // Visit all of the dex files and elements.
     55   template <typename Visitor>
     56   void Visit(const Visitor& visitor);
     57 
     58   void ClearEntries();
     59 
     60  private:
     61   // Verified methods. The method array is fixed to avoid needing a lock to extend it.
     62   using ElementArray = dchecked_vector<Atomic<T>>;
     63   using DexFileArrays = SafeMap<const DexFile*, ElementArray>;
     64 
     65   const ElementArray* GetArray(const DexFile* dex_file) const;
     66   ElementArray* GetArray(const DexFile* dex_file);
     67 
     68   DexFileArrays arrays_;
     69 };
     70 
     71 }  // namespace art
     72 
     73 #endif  // ART_COMPILER_UTILS_ATOMIC_DEX_REF_MAP_H_
     74