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1 /*
2  * Copyright (C) 2016 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 _LIBUNWINDSTACK_DWARF_SECTION_H
18 #define _LIBUNWINDSTACK_DWARF_SECTION_H
19 
20 #include <stdint.h>
21 
22 #include <iterator>
23 #include <map>
24 #include <optional>
25 #include <unordered_map>
26 
27 #include <unwindstack/DwarfError.h>
28 #include <unwindstack/DwarfLocation.h>
29 #include <unwindstack/DwarfMemory.h>
30 #include <unwindstack/DwarfStructs.h>
31 
32 namespace unwindstack {
33 
34 // Forward declarations.
35 enum ArchEnum : uint8_t;
36 class Memory;
37 class Regs;
38 template <typename AddressType>
39 struct RegsInfo;
40 
41 class DwarfSection {
42  public:
43   DwarfSection(Memory* memory);
44   virtual ~DwarfSection() = default;
45 
46   class iterator : public std::iterator<std::bidirectional_iterator_tag, DwarfFde*> {
47    public:
iterator(DwarfSection * section,size_t index)48     iterator(DwarfSection* section, size_t index) : index_(index) {
49       section->GetFdes(&fdes_);
50       if (index_ == static_cast<size_t>(-1)) {
51         index_ = fdes_.size();
52       }
53     }
54 
55     iterator& operator++() {
56       index_++;
57       return *this;
58     }
59     iterator& operator++(int increment) {
60       index_ += increment;
61       return *this;
62     }
63     iterator& operator--() {
64       index_--;
65       return *this;
66     }
67     iterator& operator--(int decrement) {
68       index_ -= decrement;
69       return *this;
70     }
71 
72     bool operator==(const iterator& rhs) { return this->index_ == rhs.index_; }
73     bool operator!=(const iterator& rhs) { return this->index_ != rhs.index_; }
74 
75     const DwarfFde* operator*() {
76       if (index_ > fdes_.size()) return nullptr;
77       return fdes_[index_];
78     }
79 
80    private:
81     std::vector<const DwarfFde*> fdes_;
82     size_t index_ = 0;
83   };
84 
begin()85   iterator begin() { return iterator(this, 0); }
end()86   iterator end() { return iterator(this, static_cast<size_t>(-1)); }
87 
LastErrorCode()88   DwarfErrorCode LastErrorCode() { return last_error_.code; }
LastErrorAddress()89   uint64_t LastErrorAddress() { return last_error_.address; }
90 
91   virtual bool Init(uint64_t offset, uint64_t size, int64_t section_bias) = 0;
92 
93   virtual bool Eval(const DwarfCie*, Memory*, const DwarfLocations&, Regs*, bool*) = 0;
94 
95   virtual bool Log(uint8_t indent, uint64_t pc, const DwarfFde* fde, ArchEnum arch) = 0;
96 
97   virtual void GetFdes(std::vector<const DwarfFde*>* fdes) = 0;
98 
99   virtual const DwarfFde* GetFdeFromPc(uint64_t pc) = 0;
100 
101   virtual bool GetCfaLocationInfo(uint64_t pc, const DwarfFde* fde, DwarfLocations* loc_regs,
102                                   ArchEnum arch) = 0;
103 
104   virtual uint64_t GetCieOffsetFromFde32(uint32_t pointer) = 0;
105 
106   virtual uint64_t GetCieOffsetFromFde64(uint64_t pointer) = 0;
107 
108   virtual uint64_t AdjustPcFromFde(uint64_t pc) = 0;
109 
110   bool Step(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished, bool* is_signal_frame);
111 
112  protected:
113   DwarfMemory memory_;
114   DwarfErrorData last_error_{DWARF_ERROR_NONE, 0};
115 
116   uint32_t cie32_value_ = 0;
117   uint64_t cie64_value_ = 0;
118 
119   std::unordered_map<uint64_t, DwarfFde> fde_entries_;
120   std::unordered_map<uint64_t, DwarfCie> cie_entries_;
121   std::unordered_map<uint64_t, DwarfLocations> cie_loc_regs_;
122   std::map<uint64_t, DwarfLocations> loc_regs_;  // Single row indexed by pc_end.
123 };
124 
125 template <typename AddressType>
126 class DwarfSectionImpl : public DwarfSection {
127  public:
DwarfSectionImpl(Memory * memory)128   DwarfSectionImpl(Memory* memory) : DwarfSection(memory) {}
129   virtual ~DwarfSectionImpl() = default;
130 
131   bool Init(uint64_t offset, uint64_t size, int64_t section_bias) override;
132 
133   const DwarfCie* GetCieFromOffset(uint64_t offset);
134 
135   const DwarfFde* GetFdeFromOffset(uint64_t offset);
136 
137   const DwarfFde* GetFdeFromPc(uint64_t pc) override;
138 
139   void GetFdes(std::vector<const DwarfFde*>* fdes) override;
140 
141   bool EvalRegister(const DwarfLocation* loc, uint32_t reg, AddressType* reg_ptr, void* info);
142 
143   bool Eval(const DwarfCie* cie, Memory* regular_memory, const DwarfLocations& loc_regs, Regs* regs,
144             bool* finished) override;
145 
146   bool GetCfaLocationInfo(uint64_t pc, const DwarfFde* fde, DwarfLocations* loc_regs,
147                           ArchEnum arch) override;
148 
149   bool Log(uint8_t indent, uint64_t pc, const DwarfFde* fde, ArchEnum arch) override;
150 
151  protected:
152   using DwarfFdeMap =
153       std::map</*end*/ uint64_t, std::pair</*start*/ uint64_t, /*offset*/ uint64_t>>;
154 
155   bool GetNextCieOrFde(/*inout*/ uint64_t& offset, /*out*/ std::optional<DwarfFde>& fde);
156 
157   bool FillInCieHeader(DwarfCie* cie);
158 
159   bool FillInCie(DwarfCie* cie);
160 
161   bool FillInFdeHeader(DwarfFde* fde);
162 
163   bool FillInFde(DwarfFde* fde);
164 
165   bool EvalExpression(const DwarfLocation& loc, Memory* regular_memory, AddressType* value,
166                       RegsInfo<AddressType>* regs_info, bool* is_dex_pc);
167 
168   static void InsertFde(uint64_t fde_offset, const DwarfFde* fde, /*out*/ DwarfFdeMap& fdes);
169 
170   void BuildFdeIndex();
171 
172   int64_t section_bias_ = 0;
173   uint64_t entries_offset_ = 0;
174   uint64_t entries_end_ = 0;
175   uint64_t pc_offset_ = 0;
176 
177   // Binary search table (similar to .eh_frame_hdr). Contains only FDE offsets to save memory.
178   std::vector<std::pair</*function end address*/ uint64_t, /*FDE offset*/ uint64_t>> fde_index_;
179 };
180 
181 }  // namespace unwindstack
182 
183 #endif  // _LIBUNWINDSTACK_DWARF_SECTION_H
184