verified_method.h revision 36b58f5ebb85d58f8b5966b8577a6dfe720d1e16 
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 "method_reference.h"
24#include "safe_map.h"
25
26namespace art {
27
28namespace verifier {
29class MethodVerifier;
30}  // namespace verifier
31
32class VerifiedMethod {
33 public:
34  // Cast elision set type.
35  // Since we're adding the dex PCs to the set in increasing order, a sorted vector
36  // is better for performance (not just memory usage), especially for large sets.
37  typedef std::vector<uint32_t> SafeCastSet;
38
39  // Devirtualization map type maps dex offset to concrete method reference.
40  typedef SafeMap<uint32_t, MethodReference> DevirtualizationMap;
41
42  static const VerifiedMethod* Create(verifier::MethodVerifier* method_verifier, bool compile)
43      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
44  ~VerifiedMethod() = default;
45
46  const std::vector<uint8_t>& GetDexGcMap() const {
47    return dex_gc_map_;
48  }
49
50  const DevirtualizationMap& GetDevirtMap() const {
51    return devirt_map_;
52  }
53
54  const SafeCastSet& GetSafeCastSet() const {
55    return safe_cast_set_;
56  }
57
58  // Returns the devirtualization target method, or nullptr if none.
59  const MethodReference* GetDevirtTarget(uint32_t dex_pc) const;
60
61  // Returns true if the cast can statically be verified to be redundant
62  // by using the check-cast elision peephole optimization in the verifier.
63  bool IsSafeCast(uint32_t pc) const;
64
65 private:
66  VerifiedMethod() = default;
67
68  /*
69   * Generate the GC map for a method that has just been verified (i.e. we're doing this as part of
70   * verification). For type-precise determination we have all the data we need, so we just need to
71   * encode it in some clever fashion.
72   * Stores the data in dex_gc_map_, returns true on success and false on failure.
73   */
74  bool GenerateGcMap(verifier::MethodVerifier* method_verifier);
75
76  // Verify that the GC map associated with method_ is well formed.
77  static void VerifyGcMap(verifier::MethodVerifier* method_verifier,
78                          const std::vector<uint8_t>& data);
79
80  // Compute sizes for GC map data.
81  static void ComputeGcMapSizes(verifier::MethodVerifier* method_verifier,
82                                size_t* gc_points, size_t* ref_bitmap_bits, size_t* log2_max_gc_pc);
83
84  // Generate devirtualizaion map into devirt_map_.
85  void GenerateDevirtMap(verifier::MethodVerifier* method_verifier)
86      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
87
88  // Generate dequickening map into dequicken_map_.
89  void GenerateDeQuickenMap(verifier::MethodVerifier* method_verifier)
90      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
91
92  // Generate safe case set into safe_cast_set_.
93  void GenerateSafeCastSet(verifier::MethodVerifier* method_verifier)
94      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
95
96  std::vector<uint8_t> dex_gc_map_;
97  DevirtualizationMap devirt_map_;
98  // Dequicken map is required for having the compiler compiled quickened invokes. The quicken map
99  // enables us to get the dex method index so that we can get the required argument count.
100  DevirtualizationMap dequicken_map_;
101  SafeCastSet safe_cast_set_;
102};
103
104}  // namespace art
105
106#endif  // ART_COMPILER_DEX_VERIFIED_METHOD_H_
107