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1 /*
2  * Copyright (C) 2018 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 #pragma once
18 
19 #include <stdint.h>
20 
21 #include <map>
22 #include <memory>
23 #include <mutex>
24 #include <string>
25 #include <utility>
26 #include <vector>
27 
28 #include <unwindstack/SharedString.h>
29 
30 #include <art_api/dex_file_support.h>
31 
32 namespace unwindstack {
33 
34 class MapInfo;
35 class Memory;
36 
37 class DexFile {
38   struct Info {
39     uint32_t offset;  // Symbol start offset (relative to start of dex file).
40     SharedString name;
41   };
42 
43  public:
IsValidPc(uint64_t dex_pc)44   bool IsValidPc(uint64_t dex_pc) {
45     return base_addr_ <= dex_pc && (dex_pc - base_addr_) < file_size_;
46   }
47 
48   bool GetFunctionName(uint64_t dex_pc, SharedString* method_name, uint64_t* method_offset);
49 
50   static std::shared_ptr<DexFile> Create(uint64_t base_addr, uint64_t file_size, Memory* memory,
51                                          MapInfo* info);
52 
53  private:
54   // The underlying C API. It might be shared by multiple DexFiles (with different base_addr).
55   struct DexFileApi {
56     std::unique_ptr<art_api::dex::DexFile> dex_;
57     std::unique_ptr<Memory> memory_;  // Keep alive the memory object backing the dex file data.
58     std::mutex lock_;                 // The C API is not thread-safe so we need to lock it.
59   };
60 
61   static std::shared_ptr<DexFile> CreateFromDisk(uint64_t addr, uint64_t size, MapInfo* map);
62 
DexFile(uint64_t base_addr,uint64_t file_size,std::shared_ptr<DexFileApi> && dex_api)63   DexFile(uint64_t base_addr, uint64_t file_size, std::shared_ptr<DexFileApi>&& dex_api)
64       : base_addr_(base_addr), file_size_(file_size), dex_api_(std::move(dex_api)) {}
65 
66   uint64_t base_addr_ = 0;               // Absolute address where this DEX file is in memory.
67   uint64_t file_size_ = 0;               // Total number of bytes in the dex file.
68   std::shared_ptr<DexFileApi> dex_api_;  // Loaded underling dex object.
69 
70   std::map<uint32_t, Info> symbols_;  // Cache of read symbols (keyed by *end* offset).
71 
72   // The same file can be mapped many times in system-wide profiling (once per process).
73   // Furthermore, the ART side of the API will create expensive PC lookup table for it.
74   // Therefore, we maintain cache to avoid loading the same file (sub-range) many times.
75   // The cache is weak: It will not keep DexFiles alive (the weak_ptr will become null).
76   using MappedFileKey = std::tuple<std::string, uint64_t, uint64_t>;  // (path, offset, size).
77   static std::map<MappedFileKey, std::weak_ptr<DexFileApi>> g_mapped_dex_files;
78   static std::mutex g_lock;  // Guards the static cache above.
79 };
80 
81 }  // namespace unwindstack
82