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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_COMPILER_OPTIMIZING_REFERENCE_TYPE_PROPAGATION_H_
     18 #define ART_COMPILER_OPTIMIZING_REFERENCE_TYPE_PROPAGATION_H_
     19 
     20 #include "base/arena_containers.h"
     21 #include "driver/dex_compilation_unit.h"
     22 #include "handle_scope-inl.h"
     23 #include "nodes.h"
     24 #include "optimization.h"
     25 #include "optimizing_compiler_stats.h"
     26 
     27 namespace art {
     28 
     29 /**
     30  * Propagates reference types to instructions.
     31  */
     32 class ReferenceTypePropagation : public HOptimization {
     33  public:
     34   ReferenceTypePropagation(HGraph* graph,
     35                            Handle<mirror::DexCache> hint_dex_cache,
     36                            StackHandleScopeCollection* handles,
     37                            bool is_first_run,
     38                            const char* name = kReferenceTypePropagationPassName);
     39 
     40   // Visit a single instruction.
     41   void Visit(HInstruction* instruction);
     42 
     43   void Run() OVERRIDE;
     44 
     45   static constexpr const char* kReferenceTypePropagationPassName = "reference_type_propagation";
     46 
     47  private:
     48   class HandleCache {
     49    public:
     50     explicit HandleCache(StackHandleScopeCollection* handles) : handles_(handles) { }
     51 
     52     template <typename T>
     53     MutableHandle<T> NewHandle(T* object) SHARED_REQUIRES(Locks::mutator_lock_) {
     54       return handles_->NewHandle(object);
     55     }
     56 
     57     ReferenceTypeInfo::TypeHandle GetObjectClassHandle();
     58     ReferenceTypeInfo::TypeHandle GetClassClassHandle();
     59     ReferenceTypeInfo::TypeHandle GetStringClassHandle();
     60     ReferenceTypeInfo::TypeHandle GetThrowableClassHandle();
     61 
     62    private:
     63     StackHandleScopeCollection* handles_;
     64 
     65     ReferenceTypeInfo::TypeHandle object_class_handle_;
     66     ReferenceTypeInfo::TypeHandle class_class_handle_;
     67     ReferenceTypeInfo::TypeHandle string_class_handle_;
     68     ReferenceTypeInfo::TypeHandle throwable_class_handle_;
     69   };
     70 
     71   class RTPVisitor;
     72 
     73   void VisitPhi(HPhi* phi);
     74   void VisitBasicBlock(HBasicBlock* block);
     75   void UpdateBoundType(HBoundType* bound_type) SHARED_REQUIRES(Locks::mutator_lock_);
     76   void UpdatePhi(HPhi* phi) SHARED_REQUIRES(Locks::mutator_lock_);
     77   void BoundTypeForIfNotNull(HBasicBlock* block);
     78   void BoundTypeForIfInstanceOf(HBasicBlock* block);
     79   void ProcessWorklist();
     80   void AddToWorklist(HInstruction* instr);
     81   void AddDependentInstructionsToWorklist(HInstruction* instr);
     82 
     83   bool UpdateNullability(HInstruction* instr);
     84   bool UpdateReferenceTypeInfo(HInstruction* instr);
     85 
     86   static void UpdateArrayGet(HArrayGet* instr, HandleCache* handle_cache)
     87       SHARED_REQUIRES(Locks::mutator_lock_);
     88 
     89   ReferenceTypeInfo MergeTypes(const ReferenceTypeInfo& a, const ReferenceTypeInfo& b)
     90       SHARED_REQUIRES(Locks::mutator_lock_);
     91 
     92   void ValidateTypes();
     93 
     94   // Note: hint_dex_cache_ is usually, but not necessarily, the dex cache associated with
     95   // graph_->GetDexFile(). Since we may look up also in other dex files, it's used only
     96   // as a hint, to reduce the number of calls to the costly ClassLinker::FindDexCache().
     97   Handle<mirror::DexCache> hint_dex_cache_;
     98   HandleCache handle_cache_;
     99 
    100   ArenaVector<HInstruction*> worklist_;
    101 
    102   // Whether this reference type propagation is the first run we are doing.
    103   const bool is_first_run_;
    104 
    105   static constexpr size_t kDefaultWorklistSize = 8;
    106 
    107   friend class ReferenceTypePropagationTest;
    108 
    109   DISALLOW_COPY_AND_ASSIGN(ReferenceTypePropagation);
    110 };
    111 
    112 }  // namespace art
    113 
    114 #endif  // ART_COMPILER_OPTIMIZING_REFERENCE_TYPE_PROPAGATION_H_
    115