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      1 /*
      2  * Copyright (C) 2014 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_DEX_VERIFIED_METHOD_H_
     18 #define ART_COMPILER_DEX_VERIFIED_METHOD_H_
     19 
     20 #include <vector>
     21 
     22 #include "base/mutex.h"
     23 #include "dex_file.h"
     24 #include "method_reference.h"
     25 #include "safe_map.h"
     26 
     27 namespace art {
     28 
     29 namespace verifier {
     30 class MethodVerifier;
     31 }  // namespace verifier
     32 
     33 class VerifiedMethod {
     34  public:
     35   // Cast elision set type.
     36   // Since we're adding the dex PCs to the set in increasing order, a sorted vector
     37   // is better for performance (not just memory usage), especially for large sets.
     38   typedef std::vector<uint32_t> SafeCastSet;
     39 
     40   // Devirtualization map type maps dex offset to concrete method reference.
     41   typedef SafeMap<uint32_t, MethodReference> DevirtualizationMap;
     42 
     43   // Devirtualization map type maps dex offset to field / method idx.
     44   typedef SafeMap<uint32_t, DexFileReference> DequickenMap;
     45 
     46   static const VerifiedMethod* Create(verifier::MethodVerifier* method_verifier, bool compile)
     47       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
     48   ~VerifiedMethod() = default;
     49 
     50   const std::vector<uint8_t>& GetDexGcMap() const {
     51     return dex_gc_map_;
     52   }
     53 
     54   const DevirtualizationMap& GetDevirtMap() const {
     55     return devirt_map_;
     56   }
     57 
     58   const SafeCastSet& GetSafeCastSet() const {
     59     return safe_cast_set_;
     60   }
     61 
     62   // Returns the devirtualization target method, or null if none.
     63   const MethodReference* GetDevirtTarget(uint32_t dex_pc) const;
     64 
     65   // Returns the dequicken field / method for a quick invoke / field get. Returns null if there is
     66   // no entry for that dex pc.
     67   const DexFileReference* GetDequickenIndex(uint32_t dex_pc) const;
     68 
     69   // Returns true if the cast can statically be verified to be redundant
     70   // by using the check-cast elision peephole optimization in the verifier.
     71   bool IsSafeCast(uint32_t pc) const;
     72 
     73   // Returns true if there were any errors during verification.
     74   bool HasVerificationFailures() const {
     75     return has_verification_failures_;
     76   }
     77 
     78   bool HasRuntimeThrow() const {
     79     return has_runtime_throw_;
     80   }
     81 
     82   void SetStringInitPcRegMap(SafeMap<uint32_t, std::set<uint32_t>>& string_init_pc_reg_map) {
     83     string_init_pc_reg_map_ = string_init_pc_reg_map;
     84   }
     85   const SafeMap<uint32_t, std::set<uint32_t>>& GetStringInitPcRegMap() const {
     86     return string_init_pc_reg_map_;
     87   }
     88 
     89  private:
     90   VerifiedMethod() = default;
     91 
     92   /*
     93    * Generate the GC map for a method that has just been verified (i.e. we're doing this as part of
     94    * verification). For type-precise determination we have all the data we need, so we just need to
     95    * encode it in some clever fashion.
     96    * Stores the data in dex_gc_map_, returns true on success and false on failure.
     97    */
     98   bool GenerateGcMap(verifier::MethodVerifier* method_verifier);
     99 
    100   // Verify that the GC map associated with method_ is well formed.
    101   static void VerifyGcMap(verifier::MethodVerifier* method_verifier,
    102                           const std::vector<uint8_t>& data);
    103 
    104   // Compute sizes for GC map data.
    105   static void ComputeGcMapSizes(verifier::MethodVerifier* method_verifier,
    106                                 size_t* gc_points, size_t* ref_bitmap_bits, size_t* log2_max_gc_pc);
    107 
    108   // Generate devirtualizaion map into devirt_map_.
    109   void GenerateDevirtMap(verifier::MethodVerifier* method_verifier)
    110       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    111 
    112   // Generate dequickening map into dequicken_map_. Returns false if there is an error.
    113   bool GenerateDequickenMap(verifier::MethodVerifier* method_verifier)
    114       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    115 
    116   // Generate safe case set into safe_cast_set_.
    117   void GenerateSafeCastSet(verifier::MethodVerifier* method_verifier)
    118       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
    119 
    120   std::vector<uint8_t> dex_gc_map_;
    121   DevirtualizationMap devirt_map_;
    122   // Dequicken map is required for compiling quickened byte codes. The quicken maps from
    123   // dex PC to dex method index or dex field index based on the instruction.
    124   DequickenMap dequicken_map_;
    125   SafeCastSet safe_cast_set_;
    126 
    127   bool has_verification_failures_;
    128   bool has_runtime_throw_ = false;
    129 
    130   // Copy of mapping generated by verifier of dex PCs of string init invocations
    131   // to the set of other registers that the receiver has been copied into.
    132   SafeMap<uint32_t, std::set<uint32_t>> string_init_pc_reg_map_;
    133 };
    134 
    135 }  // namespace art
    136 
    137 #endif  // ART_COMPILER_DEX_VERIFIED_METHOD_H_
    138