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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 "obj_ptr.h"
     25 #include "optimization.h"
     26 #include "optimizing_compiler_stats.h"
     27 
     28 namespace art {
     29 
     30 /**
     31  * Propagates reference types to instructions.
     32  */
     33 class ReferenceTypePropagation : public HOptimization {
     34  public:
     35   ReferenceTypePropagation(HGraph* graph,
     36                            Handle<mirror::ClassLoader> class_loader,
     37                            Handle<mirror::DexCache> hint_dex_cache,
     38                            VariableSizedHandleScope* handles,
     39                            bool is_first_run,
     40                            const char* name = kReferenceTypePropagationPassName);
     41 
     42   // Visit a single instruction.
     43   void Visit(HInstruction* instruction);
     44 
     45   void Run() OVERRIDE;
     46 
     47   // Returns true if klass is admissible to the propagation: non-null and resolved.
     48   // For an array type, we also check if the component type is admissible.
     49   static bool IsAdmissible(mirror::Class* klass) REQUIRES_SHARED(Locks::mutator_lock_) {
     50     return klass != nullptr &&
     51            klass->IsResolved() &&
     52            (!klass->IsArrayClass() || IsAdmissible(klass->GetComponentType()));
     53   }
     54 
     55   static constexpr const char* kReferenceTypePropagationPassName = "reference_type_propagation";
     56 
     57  private:
     58   class HandleCache {
     59    public:
     60     explicit HandleCache(VariableSizedHandleScope* handles) : handles_(handles) { }
     61 
     62     template <typename T>
     63     MutableHandle<T> NewHandle(T* object) REQUIRES_SHARED(Locks::mutator_lock_) {
     64       return handles_->NewHandle(object);
     65     }
     66 
     67     template <typename T>
     68     MutableHandle<T> NewHandle(ObjPtr<T> object) REQUIRES_SHARED(Locks::mutator_lock_) {
     69       return handles_->NewHandle(object);
     70     }
     71 
     72     ReferenceTypeInfo::TypeHandle GetObjectClassHandle();
     73     ReferenceTypeInfo::TypeHandle GetClassClassHandle();
     74     ReferenceTypeInfo::TypeHandle GetStringClassHandle();
     75     ReferenceTypeInfo::TypeHandle GetThrowableClassHandle();
     76 
     77    private:
     78     VariableSizedHandleScope* handles_;
     79 
     80     ReferenceTypeInfo::TypeHandle object_class_handle_;
     81     ReferenceTypeInfo::TypeHandle class_class_handle_;
     82     ReferenceTypeInfo::TypeHandle string_class_handle_;
     83     ReferenceTypeInfo::TypeHandle throwable_class_handle_;
     84   };
     85 
     86   class RTPVisitor;
     87 
     88   void VisitPhi(HPhi* phi);
     89   void VisitBasicBlock(HBasicBlock* block);
     90   void UpdateBoundType(HBoundType* bound_type) REQUIRES_SHARED(Locks::mutator_lock_);
     91   void UpdatePhi(HPhi* phi) REQUIRES_SHARED(Locks::mutator_lock_);
     92   void BoundTypeForIfNotNull(HBasicBlock* block);
     93   void BoundTypeForIfInstanceOf(HBasicBlock* block);
     94   void ProcessWorklist();
     95   void AddToWorklist(HInstruction* instr);
     96   void AddDependentInstructionsToWorklist(HInstruction* instr);
     97 
     98   bool UpdateNullability(HInstruction* instr);
     99   bool UpdateReferenceTypeInfo(HInstruction* instr);
    100 
    101   static void UpdateArrayGet(HArrayGet* instr, HandleCache* handle_cache)
    102       REQUIRES_SHARED(Locks::mutator_lock_);
    103 
    104   ReferenceTypeInfo MergeTypes(const ReferenceTypeInfo& a, const ReferenceTypeInfo& b)
    105       REQUIRES_SHARED(Locks::mutator_lock_);
    106 
    107   void ValidateTypes();
    108 
    109   Handle<mirror::ClassLoader> class_loader_;
    110 
    111   // Note: hint_dex_cache_ is usually, but not necessarily, the dex cache associated with
    112   // graph_->GetDexFile(). Since we may look up also in other dex files, it's used only
    113   // as a hint, to reduce the number of calls to the costly ClassLinker::FindDexCache().
    114   Handle<mirror::DexCache> hint_dex_cache_;
    115   HandleCache handle_cache_;
    116 
    117   ArenaVector<HInstruction*> worklist_;
    118 
    119   // Whether this reference type propagation is the first run we are doing.
    120   const bool is_first_run_;
    121 
    122   static constexpr size_t kDefaultWorklistSize = 8;
    123 
    124   friend class ReferenceTypePropagationTest;
    125 
    126   DISALLOW_COPY_AND_ASSIGN(ReferenceTypePropagation);
    127 };
    128 
    129 }  // namespace art
    130 
    131 #endif  // ART_COMPILER_OPTIMIZING_REFERENCE_TYPE_PROPAGATION_H_
    132