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_REQUIRES(Locks::mutator_lock_);
48   ~VerifiedMethod() = default;
49 
GetDevirtMap()50   const DevirtualizationMap& GetDevirtMap() const {
51     return devirt_map_;
52   }
53 
GetSafeCastSet()54   const SafeCastSet& GetSafeCastSet() const {
55     return safe_cast_set_;
56   }
57 
58   // Returns the devirtualization target method, or null if none.
59   const MethodReference* GetDevirtTarget(uint32_t dex_pc) const;
60 
61   // Returns the dequicken field / method for a quick invoke / field get. Returns null if there is
62   // no entry for that dex pc.
63   const DexFileReference* GetDequickenIndex(uint32_t dex_pc) const;
64 
65   // Returns true if the cast can statically be verified to be redundant
66   // by using the check-cast elision peephole optimization in the verifier.
67   bool IsSafeCast(uint32_t pc) const;
68 
69   // Returns true if there were any errors during verification.
HasVerificationFailures()70   bool HasVerificationFailures() const {
71     return encountered_error_types_ != 0;
72   }
73 
GetEncounteredVerificationFailures()74   uint32_t GetEncounteredVerificationFailures() const {
75     return encountered_error_types_;
76   }
77 
HasRuntimeThrow()78   bool HasRuntimeThrow() const {
79     return has_runtime_throw_;
80   }
81 
82  private:
83   VerifiedMethod(uint32_t encountered_error_types, bool has_runtime_throw);
84 
85   /*
86    * Generate the GC map for a method that has just been verified (i.e. we're doing this as part of
87    * verification). For type-precise determination we have all the data we need, so we just need to
88    * encode it in some clever fashion.
89    * Stores the data in dex_gc_map_, returns true on success and false on failure.
90    */
91   bool GenerateGcMap(verifier::MethodVerifier* method_verifier);
92 
93   // Verify that the GC map associated with method_ is well formed.
94   static void VerifyGcMap(verifier::MethodVerifier* method_verifier,
95                           const std::vector<uint8_t>& data);
96 
97   // Compute sizes for GC map data.
98   static void ComputeGcMapSizes(verifier::MethodVerifier* method_verifier,
99                                 size_t* gc_points, size_t* ref_bitmap_bits, size_t* log2_max_gc_pc);
100 
101   // Generate devirtualizaion map into devirt_map_.
102   void GenerateDevirtMap(verifier::MethodVerifier* method_verifier)
103       SHARED_REQUIRES(Locks::mutator_lock_);
104 
105   // Generate dequickening map into dequicken_map_. Returns false if there is an error.
106   bool GenerateDequickenMap(verifier::MethodVerifier* method_verifier)
107       SHARED_REQUIRES(Locks::mutator_lock_);
108 
109   // Generate safe case set into safe_cast_set_.
110   void GenerateSafeCastSet(verifier::MethodVerifier* method_verifier)
111       SHARED_REQUIRES(Locks::mutator_lock_);
112 
113   DevirtualizationMap devirt_map_;
114   // Dequicken map is required for compiling quickened byte codes. The quicken maps from
115   // dex PC to dex method index or dex field index based on the instruction.
116   DequickenMap dequicken_map_;
117   SafeCastSet safe_cast_set_;
118 
119   const uint32_t encountered_error_types_;
120   const bool has_runtime_throw_;
121 };
122 
123 }  // namespace art
124 
125 #endif  // ART_COMPILER_DEX_VERIFIED_METHOD_H_
126