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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_CFA_H
18 #define _LIBUNWINDSTACK_DWARF_CFA_H
19 
20 #include <stdint.h>
21 
22 #include <stack>
23 #include <string>
24 #include <type_traits>
25 #include <vector>
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 // DWARF Standard home: http://dwarfstd.org/
35 // This code is based on DWARF 4: http://http://dwarfstd.org/doc/DWARF4.pdf
36 // See section 6.4.2.1 for a description of the DW_CFA_xxx values.
37 
38 class DwarfCfaInfo {
39  public:
40   enum DisplayType : uint8_t {
41     DWARF_DISPLAY_NONE = 0,
42     DWARF_DISPLAY_REGISTER,
43     DWARF_DISPLAY_NUMBER,
44     DWARF_DISPLAY_SIGNED_NUMBER,
45     DWARF_DISPLAY_EVAL_BLOCK,
46     DWARF_DISPLAY_ADDRESS,
47     DWARF_DISPLAY_SET_LOC,
48     DWARF_DISPLAY_ADVANCE_LOC,
49   };
50 
51   struct Info {
52     const char* name;
53     uint8_t supported_version;
54     uint8_t num_operands;
55     uint8_t operands[2];
56     uint8_t display_operands[2];
57   };
58 
59   const static Info kTable[64];
60 };
61 
62 template <typename AddressType>
63 class DwarfCfa {
64   // Signed version of AddressType
65   typedef typename std::make_signed<AddressType>::type SignedType;
66 
67  public:
DwarfCfa(DwarfMemory * memory,const DwarfFde * fde)68   DwarfCfa(DwarfMemory* memory, const DwarfFde* fde) : memory_(memory), fde_(fde) {}
69   virtual ~DwarfCfa() = default;
70 
71   bool GetLocationInfo(uint64_t pc, uint64_t start_offset, uint64_t end_offset,
72                        dwarf_loc_regs_t* loc_regs);
73 
74   bool Log(uint32_t indent, uint64_t pc, uint64_t load_bias, uint64_t start_offset,
75            uint64_t end_offset);
76 
last_error()77   const DwarfErrorData& last_error() { return last_error_; }
LastErrorCode()78   DwarfErrorCode LastErrorCode() { return last_error_.code; }
LastErrorAddress()79   uint64_t LastErrorAddress() { return last_error_.address; }
80 
cur_pc()81   AddressType cur_pc() { return cur_pc_; }
82 
set_cie_loc_regs(const dwarf_loc_regs_t * cie_loc_regs)83   void set_cie_loc_regs(const dwarf_loc_regs_t* cie_loc_regs) { cie_loc_regs_ = cie_loc_regs; }
84 
85  protected:
86   std::string GetOperandString(uint8_t operand, uint64_t value, uint64_t* cur_pc);
87 
88   bool LogOffsetRegisterString(uint32_t indent, uint64_t cfa_offset, uint8_t reg);
89 
90   bool LogInstruction(uint32_t indent, uint64_t cfa_offset, uint8_t op, uint64_t* cur_pc);
91 
92  private:
93   DwarfErrorData last_error_;
94   DwarfMemory* memory_;
95   const DwarfFde* fde_;
96 
97   AddressType cur_pc_;
98   const dwarf_loc_regs_t* cie_loc_regs_ = nullptr;
99   std::vector<AddressType> operands_;
100   std::stack<dwarf_loc_regs_t> loc_reg_state_;
101 
102   // CFA processing functions.
103   bool cfa_nop(dwarf_loc_regs_t*);
104   bool cfa_set_loc(dwarf_loc_regs_t*);
105   bool cfa_advance_loc(dwarf_loc_regs_t*);
106   bool cfa_offset(dwarf_loc_regs_t*);
107   bool cfa_restore(dwarf_loc_regs_t*);
108   bool cfa_undefined(dwarf_loc_regs_t*);
109   bool cfa_same_value(dwarf_loc_regs_t*);
110   bool cfa_register(dwarf_loc_regs_t*);
111   bool cfa_remember_state(dwarf_loc_regs_t*);
112   bool cfa_restore_state(dwarf_loc_regs_t*);
113   bool cfa_def_cfa(dwarf_loc_regs_t*);
114   bool cfa_def_cfa_register(dwarf_loc_regs_t*);
115   bool cfa_def_cfa_offset(dwarf_loc_regs_t*);
116   bool cfa_def_cfa_expression(dwarf_loc_regs_t*);
117   bool cfa_expression(dwarf_loc_regs_t*);
118   bool cfa_offset_extended_sf(dwarf_loc_regs_t*);
119   bool cfa_def_cfa_sf(dwarf_loc_regs_t*);
120   bool cfa_def_cfa_offset_sf(dwarf_loc_regs_t*);
121   bool cfa_val_offset(dwarf_loc_regs_t*);
122   bool cfa_val_offset_sf(dwarf_loc_regs_t*);
123   bool cfa_val_expression(dwarf_loc_regs_t*);
124   bool cfa_gnu_negative_offset_extended(dwarf_loc_regs_t*);
125 
126   using process_func = bool (DwarfCfa::*)(dwarf_loc_regs_t*);
127   constexpr static process_func kCallbackTable[64] = {
128       // 0x00 DW_CFA_nop
129       &DwarfCfa::cfa_nop,
130       // 0x01 DW_CFA_set_loc
131       &DwarfCfa::cfa_set_loc,
132       // 0x02 DW_CFA_advance_loc1
133       &DwarfCfa::cfa_advance_loc,
134       // 0x03 DW_CFA_advance_loc2
135       &DwarfCfa::cfa_advance_loc,
136       // 0x04 DW_CFA_advance_loc4
137       &DwarfCfa::cfa_advance_loc,
138       // 0x05 DW_CFA_offset_extended
139       &DwarfCfa::cfa_offset,
140       // 0x06 DW_CFA_restore_extended
141       &DwarfCfa::cfa_restore,
142       // 0x07 DW_CFA_undefined
143       &DwarfCfa::cfa_undefined,
144       // 0x08 DW_CFA_same_value
145       &DwarfCfa::cfa_same_value,
146       // 0x09 DW_CFA_register
147       &DwarfCfa::cfa_register,
148       // 0x0a DW_CFA_remember_state
149       &DwarfCfa::cfa_remember_state,
150       // 0x0b DW_CFA_restore_state
151       &DwarfCfa::cfa_restore_state,
152       // 0x0c DW_CFA_def_cfa
153       &DwarfCfa::cfa_def_cfa,
154       // 0x0d DW_CFA_def_cfa_register
155       &DwarfCfa::cfa_def_cfa_register,
156       // 0x0e DW_CFA_def_cfa_offset
157       &DwarfCfa::cfa_def_cfa_offset,
158       // 0x0f DW_CFA_def_cfa_expression
159       &DwarfCfa::cfa_def_cfa_expression,
160       // 0x10 DW_CFA_expression
161       &DwarfCfa::cfa_expression,
162       // 0x11 DW_CFA_offset_extended_sf
163       &DwarfCfa::cfa_offset_extended_sf,
164       // 0x12 DW_CFA_def_cfa_sf
165       &DwarfCfa::cfa_def_cfa_sf,
166       // 0x13 DW_CFA_def_cfa_offset_sf
167       &DwarfCfa::cfa_def_cfa_offset_sf,
168       // 0x14 DW_CFA_val_offset
169       &DwarfCfa::cfa_val_offset,
170       // 0x15 DW_CFA_val_offset_sf
171       &DwarfCfa::cfa_val_offset_sf,
172       // 0x16 DW_CFA_val_expression
173       &DwarfCfa::cfa_val_expression,
174       // 0x17 illegal cfa
175       nullptr,
176       // 0x18 illegal cfa
177       nullptr,
178       // 0x19 illegal cfa
179       nullptr,
180       // 0x1a illegal cfa
181       nullptr,
182       // 0x1b illegal cfa
183       nullptr,
184       // 0x1c DW_CFA_lo_user (Treat this as illegal)
185       nullptr,
186       // 0x1d illegal cfa
187       nullptr,
188       // 0x1e illegal cfa
189       nullptr,
190       // 0x1f illegal cfa
191       nullptr,
192       // 0x20 illegal cfa
193       nullptr,
194       // 0x21 illegal cfa
195       nullptr,
196       // 0x22 illegal cfa
197       nullptr,
198       // 0x23 illegal cfa
199       nullptr,
200       // 0x24 illegal cfa
201       nullptr,
202       // 0x25 illegal cfa
203       nullptr,
204       // 0x26 illegal cfa
205       nullptr,
206       // 0x27 illegal cfa
207       nullptr,
208       // 0x28 illegal cfa
209       nullptr,
210       // 0x29 illegal cfa
211       nullptr,
212       // 0x2a illegal cfa
213       nullptr,
214       // 0x2b illegal cfa
215       nullptr,
216       // 0x2c illegal cfa
217       nullptr,
218       // 0x2d DW_CFA_GNU_window_save (Treat this as illegal)
219       nullptr,
220       // 0x2e DW_CFA_GNU_args_size
221       &DwarfCfa::cfa_nop,
222       // 0x2f DW_CFA_GNU_negative_offset_extended
223       &DwarfCfa::cfa_gnu_negative_offset_extended,
224       // 0x30 illegal cfa
225       nullptr,
226       // 0x31 illegal cfa
227       nullptr,
228       // 0x32 illegal cfa
229       nullptr,
230       // 0x33 illegal cfa
231       nullptr,
232       // 0x34 illegal cfa
233       nullptr,
234       // 0x35 illegal cfa
235       nullptr,
236       // 0x36 illegal cfa
237       nullptr,
238       // 0x37 illegal cfa
239       nullptr,
240       // 0x38 illegal cfa
241       nullptr,
242       // 0x39 illegal cfa
243       nullptr,
244       // 0x3a illegal cfa
245       nullptr,
246       // 0x3b illegal cfa
247       nullptr,
248       // 0x3c illegal cfa
249       nullptr,
250       // 0x3d illegal cfa
251       nullptr,
252       // 0x3e illegal cfa
253       nullptr,
254       // 0x3f DW_CFA_hi_user (Treat this as illegal)
255       nullptr,
256   };
257 };
258 
259 }  // namespace unwindstack
260 
261 #endif  // _LIBUNWINDSTACK_DWARF_CFA_H
262