Home | History | Annotate | Download | only in optimizing 
      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 "mirror/class-inl.h"
     22 #include "nodes.h"
     23 #include "obj_ptr.h"
     24 #include "optimization.h"
     25 
     26 namespace art {
     27 
     28 /**
     29  * Propagates reference types to instructions.
     30  */
     31 class ReferenceTypePropagation : public HOptimization {
     32  public:
     33   ReferenceTypePropagation(HGraph* graph,
     34                            Handle<mirror::ClassLoader> class_loader,
     35                            Handle<mirror::DexCache> hint_dex_cache,
     36                            VariableSizedHandleScope* 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   // Returns true if klass is admissible to the propagation: non-null and resolved.
     46   // For an array type, we also check if the component type is admissible.
     47   static bool IsAdmissible(ObjPtr<mirror::Class> klass) REQUIRES_SHARED(Locks::mutator_lock_) {
     48     return klass != nullptr &&
     49            klass->IsResolved() &&
     50            (!klass->IsArrayClass() || IsAdmissible(klass->GetComponentType()));
     51   }
     52 
     53   static constexpr const char* kReferenceTypePropagationPassName = "reference_type_propagation";
     54 
     55   // Fix the reference type for an instruction whose inputs have changed.
     56   // For a select instruction, the reference types of the inputs are merged
     57   // and the resulting reference type is set on the select instruction.
     58   static void FixUpInstructionType(HInstruction* instruction,
     59                                    VariableSizedHandleScope* handle_scope);
     60 
     61  private:
     62   class HandleCache {
     63    public:
     64     explicit HandleCache(VariableSizedHandleScope* handles) : handles_(handles) { }
     65 
     66     template <typename T>
     67     MutableHandle<T> NewHandle(T* object) REQUIRES_SHARED(Locks::mutator_lock_) {
     68       return handles_->NewHandle(object);
     69     }
     70 
     71     template <typename T>
     72     MutableHandle<T> NewHandle(ObjPtr<T> object) REQUIRES_SHARED(Locks::mutator_lock_) {
     73       return handles_->NewHandle(object);
     74     }
     75 
     76     ReferenceTypeInfo::TypeHandle GetObjectClassHandle();
     77     ReferenceTypeInfo::TypeHandle GetClassClassHandle();
     78     ReferenceTypeInfo::TypeHandle GetStringClassHandle();
     79     ReferenceTypeInfo::TypeHandle GetThrowableClassHandle();
     80 
     81    private:
     82     VariableSizedHandleScope* handles_;
     83 
     84     ReferenceTypeInfo::TypeHandle object_class_handle_;
     85     ReferenceTypeInfo::TypeHandle class_class_handle_;
     86     ReferenceTypeInfo::TypeHandle string_class_handle_;
     87     ReferenceTypeInfo::TypeHandle throwable_class_handle_;
     88   };
     89 
     90   class RTPVisitor;
     91 
     92   static ReferenceTypeInfo MergeTypes(const ReferenceTypeInfo& a,
     93                                       const ReferenceTypeInfo& b,
     94                                       HandleCache* handle_cache)
     95       REQUIRES_SHARED(Locks::mutator_lock_);
     96 
     97   void ValidateTypes();
     98 
     99   Handle<mirror::ClassLoader> class_loader_;
    100 
    101   // Note: hint_dex_cache_ is usually, but not necessarily, the dex cache associated with
    102   // graph_->GetDexFile(). Since we may look up also in other dex files, it's used only
    103   // as a hint, to reduce the number of calls to the costly ClassLinker::FindDexCache().
    104   Handle<mirror::DexCache> hint_dex_cache_;
    105   HandleCache handle_cache_;
    106 
    107   // Whether this reference type propagation is the first run we are doing.
    108   const bool is_first_run_;
    109 
    110   friend class ReferenceTypePropagationTest;
    111 
    112   DISALLOW_COPY_AND_ASSIGN(ReferenceTypePropagation);
    113 };
    114 
    115 }  // namespace art
    116 
    117 #endif  // ART_COMPILER_OPTIMIZING_REFERENCE_TYPE_PROPAGATION_H_
    118