verified_method.h revision 2535abe7d1fcdd0e6aca782b1f1932a703ed50a4 
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
27namespace art {
28
29namespace verifier {
30class MethodVerifier;
31}  // namespace verifier
32
33class 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 nullptr 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 private:
74  VerifiedMethod() = default;
75
76  /*
77   * Generate the GC map for a method that has just been verified (i.e. we're doing this as part of
78   * verification). For type-precise determination we have all the data we need, so we just need to
79   * encode it in some clever fashion.
80   * Stores the data in dex_gc_map_, returns true on success and false on failure.
81   */
82  bool GenerateGcMap(verifier::MethodVerifier* method_verifier);
83
84  // Verify that the GC map associated with method_ is well formed.
85  static void VerifyGcMap(verifier::MethodVerifier* method_verifier,
86                          const std::vector<uint8_t>& data);
87
88  // Compute sizes for GC map data.
89  static void ComputeGcMapSizes(verifier::MethodVerifier* method_verifier,
90                                size_t* gc_points, size_t* ref_bitmap_bits, size_t* log2_max_gc_pc);
91
92  // Generate devirtualizaion map into devirt_map_.
93  void GenerateDevirtMap(verifier::MethodVerifier* method_verifier)
94      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
95
96  // Generate dequickening map into dequicken_map_.
97  void GenerateDequickenMap(verifier::MethodVerifier* method_verifier)
98      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
99
100  // Generate safe case set into safe_cast_set_.
101  void GenerateSafeCastSet(verifier::MethodVerifier* method_verifier)
102      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
103
104  std::vector<uint8_t> dex_gc_map_;
105  DevirtualizationMap devirt_map_;
106  // Dequicken map is required for compiling quickened byte codes. The quicken maps from
107  // dex PC to dex method index or dex field index based on the instruction.
108  DequickenMap dequicken_map_;
109  SafeCastSet safe_cast_set_;
110};
111
112}  // namespace art
113
114#endif  // ART_COMPILER_DEX_VERIFIED_METHOD_H_
115