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 #pragma once
18 
19 #include <stdint.h>
20 
21 #include <stack>
22 #include <string>
23 #include <type_traits>
24 #include <vector>
25 
26 #include <unwindstack/DwarfError.h>
27 #include <unwindstack/DwarfLocation.h>
28 #include <unwindstack/DwarfMemory.h>
29 #include <unwindstack/DwarfStructs.h>
30 
31 namespace unwindstack {
32 
33 // Forward declarations.
34 enum ArchEnum : uint8_t;
35 
36 // DWARF Standard home: http://dwarfstd.org/
37 // This code is based on DWARF 4: http://http://dwarfstd.org/doc/DWARF4.pdf
38 // See section 6.4.2.1 for a description of the DW_CFA_xxx values.
39 
40 class DwarfCfaInfo {
41  public:
42   enum DisplayType : uint8_t {
43     DWARF_DISPLAY_NONE = 0,
44     DWARF_DISPLAY_REGISTER,
45     DWARF_DISPLAY_NUMBER,
46     DWARF_DISPLAY_SIGNED_NUMBER,
47     DWARF_DISPLAY_EVAL_BLOCK,
48     DWARF_DISPLAY_ADDRESS,
49     DWARF_DISPLAY_SET_LOC,
50     DWARF_DISPLAY_ADVANCE_LOC,
51   };
52 
53   struct Info {
54     // It may seem cleaner to just change the type of 'name' to 'const char *'.
55     // However, having a pointer here would require relocation at runtime,
56     // causing 'kTable' to be placed in data.rel.ro section instead of rodata
57     // section, adding memory pressure to the system.  Note that this is only
58     // safe because this is only used in C++ code.  C++ standard, unlike C
59     // standard, mandates the array size to be large enough to hold the NULL
60     // terminator when initialized with a string literal.
61     const char name[36];
62     uint8_t supported_version;
63     uint8_t num_operands;
64     uint8_t operands[2];
65     uint8_t display_operands[2];
66   };
67 
68   const static Info kTable[64];
69 };
70 
71 template <typename AddressType>
72 class DwarfCfa {
73   // Signed version of AddressType
74   typedef typename std::make_signed<AddressType>::type SignedType;
75 
76  public:
DwarfCfa(DwarfMemory * memory,const DwarfFde * fde,ArchEnum arch)77   DwarfCfa(DwarfMemory* memory, const DwarfFde* fde, ArchEnum arch)
78       : memory_(memory), fde_(fde), arch_(arch) {}
79   virtual ~DwarfCfa() = default;
80 
81   bool GetLocationInfo(uint64_t pc, uint64_t start_offset, uint64_t end_offset,
82                        DwarfLocations* loc_regs);
83 
84   bool Log(uint32_t indent, uint64_t pc, uint64_t start_offset, uint64_t end_offset);
85 
last_error()86   const DwarfErrorData& last_error() { return last_error_; }
LastErrorCode()87   DwarfErrorCode LastErrorCode() { return last_error_.code; }
LastErrorAddress()88   uint64_t LastErrorAddress() { return last_error_.address; }
89 
cur_pc()90   AddressType cur_pc() { return cur_pc_; }
91 
set_cie_loc_regs(const DwarfLocations * cie_loc_regs)92   void set_cie_loc_regs(const DwarfLocations* cie_loc_regs) { cie_loc_regs_ = cie_loc_regs; }
93 
94  protected:
95   std::string GetOperandString(uint8_t operand, uint64_t value, uint64_t* cur_pc);
96 
97   bool LogOffsetRegisterString(uint32_t indent, uint64_t cfa_offset, uint8_t reg);
98 
99   bool LogInstruction(uint32_t indent, uint64_t cfa_offset, uint8_t op, uint64_t* cur_pc);
100 
101  private:
102   DwarfErrorData last_error_;
103   DwarfMemory* memory_;
104   const DwarfFde* fde_;
105   ArchEnum arch_;
106 
107   AddressType cur_pc_;
108   const DwarfLocations* cie_loc_regs_ = nullptr;
109   std::vector<AddressType> operands_;
110   std::stack<DwarfLocations> loc_reg_state_;
111 
112   // CFA processing functions.
113   bool cfa_nop(DwarfLocations*);
114   bool cfa_set_loc(DwarfLocations*);
115   bool cfa_advance_loc(DwarfLocations*);
116   bool cfa_offset(DwarfLocations*);
117   bool cfa_restore(DwarfLocations*);
118   bool cfa_undefined(DwarfLocations*);
119   bool cfa_same_value(DwarfLocations*);
120   bool cfa_register(DwarfLocations*);
121   bool cfa_remember_state(DwarfLocations*);
122   bool cfa_restore_state(DwarfLocations*);
123   bool cfa_def_cfa(DwarfLocations*);
124   bool cfa_def_cfa_register(DwarfLocations*);
125   bool cfa_def_cfa_offset(DwarfLocations*);
126   bool cfa_def_cfa_expression(DwarfLocations*);
127   bool cfa_expression(DwarfLocations*);
128   bool cfa_offset_extended_sf(DwarfLocations*);
129   bool cfa_def_cfa_sf(DwarfLocations*);
130   bool cfa_def_cfa_offset_sf(DwarfLocations*);
131   bool cfa_val_offset(DwarfLocations*);
132   bool cfa_val_offset_sf(DwarfLocations*);
133   bool cfa_val_expression(DwarfLocations*);
134   bool cfa_gnu_negative_offset_extended(DwarfLocations*);
135   bool cfa_aarch64_negate_ra_state(DwarfLocations*);
136 
137   using process_func = bool (DwarfCfa::*)(DwarfLocations*);
138   constexpr static process_func kCallbackTable[64] = {
139       // 0x00 DW_CFA_nop
140       &DwarfCfa::cfa_nop,
141       // 0x01 DW_CFA_set_loc
142       &DwarfCfa::cfa_set_loc,
143       // 0x02 DW_CFA_advance_loc1
144       &DwarfCfa::cfa_advance_loc,
145       // 0x03 DW_CFA_advance_loc2
146       &DwarfCfa::cfa_advance_loc,
147       // 0x04 DW_CFA_advance_loc4
148       &DwarfCfa::cfa_advance_loc,
149       // 0x05 DW_CFA_offset_extended
150       &DwarfCfa::cfa_offset,
151       // 0x06 DW_CFA_restore_extended
152       &DwarfCfa::cfa_restore,
153       // 0x07 DW_CFA_undefined
154       &DwarfCfa::cfa_undefined,
155       // 0x08 DW_CFA_same_value
156       &DwarfCfa::cfa_same_value,
157       // 0x09 DW_CFA_register
158       &DwarfCfa::cfa_register,
159       // 0x0a DW_CFA_remember_state
160       &DwarfCfa::cfa_remember_state,
161       // 0x0b DW_CFA_restore_state
162       &DwarfCfa::cfa_restore_state,
163       // 0x0c DW_CFA_def_cfa
164       &DwarfCfa::cfa_def_cfa,
165       // 0x0d DW_CFA_def_cfa_register
166       &DwarfCfa::cfa_def_cfa_register,
167       // 0x0e DW_CFA_def_cfa_offset
168       &DwarfCfa::cfa_def_cfa_offset,
169       // 0x0f DW_CFA_def_cfa_expression
170       &DwarfCfa::cfa_def_cfa_expression,
171       // 0x10 DW_CFA_expression
172       &DwarfCfa::cfa_expression,
173       // 0x11 DW_CFA_offset_extended_sf
174       &DwarfCfa::cfa_offset_extended_sf,
175       // 0x12 DW_CFA_def_cfa_sf
176       &DwarfCfa::cfa_def_cfa_sf,
177       // 0x13 DW_CFA_def_cfa_offset_sf
178       &DwarfCfa::cfa_def_cfa_offset_sf,
179       // 0x14 DW_CFA_val_offset
180       &DwarfCfa::cfa_val_offset,
181       // 0x15 DW_CFA_val_offset_sf
182       &DwarfCfa::cfa_val_offset_sf,
183       // 0x16 DW_CFA_val_expression
184       &DwarfCfa::cfa_val_expression,
185       // 0x17 illegal cfa
186       nullptr,
187       // 0x18 illegal cfa
188       nullptr,
189       // 0x19 illegal cfa
190       nullptr,
191       // 0x1a illegal cfa
192       nullptr,
193       // 0x1b illegal cfa
194       nullptr,
195       // 0x1c DW_CFA_lo_user (Treat this as illegal)
196       nullptr,
197       // 0x1d illegal cfa
198       nullptr,
199       // 0x1e illegal cfa
200       nullptr,
201       // 0x1f illegal cfa
202       nullptr,
203       // 0x20 illegal cfa
204       nullptr,
205       // 0x21 illegal cfa
206       nullptr,
207       // 0x22 illegal cfa
208       nullptr,
209       // 0x23 illegal cfa
210       nullptr,
211       // 0x24 illegal cfa
212       nullptr,
213       // 0x25 illegal cfa
214       nullptr,
215       // 0x26 illegal cfa
216       nullptr,
217       // 0x27 illegal cfa
218       nullptr,
219       // 0x28 illegal cfa
220       nullptr,
221       // 0x29 illegal cfa
222       nullptr,
223       // 0x2a illegal cfa
224       nullptr,
225       // 0x2b illegal cfa
226       nullptr,
227       // 0x2c illegal cfa
228       nullptr,
229       // 0x2d DW_CFA_AARCH64_negate_ra_state (aarch64 only)
230       // DW_CFA_GNU_window_save on other architectures.
231       &DwarfCfa::cfa_aarch64_negate_ra_state,
232       // 0x2e DW_CFA_GNU_args_size
233       &DwarfCfa::cfa_nop,
234       // 0x2f DW_CFA_GNU_negative_offset_extended
235       &DwarfCfa::cfa_gnu_negative_offset_extended,
236       // 0x30 illegal cfa
237       nullptr,
238       // 0x31 illegal cfa
239       nullptr,
240       // 0x32 illegal cfa
241       nullptr,
242       // 0x33 illegal cfa
243       nullptr,
244       // 0x34 illegal cfa
245       nullptr,
246       // 0x35 illegal cfa
247       nullptr,
248       // 0x36 illegal cfa
249       nullptr,
250       // 0x37 illegal cfa
251       nullptr,
252       // 0x38 illegal cfa
253       nullptr,
254       // 0x39 illegal cfa
255       nullptr,
256       // 0x3a illegal cfa
257       nullptr,
258       // 0x3b illegal cfa
259       nullptr,
260       // 0x3c illegal cfa
261       nullptr,
262       // 0x3d illegal cfa
263       nullptr,
264       // 0x3e illegal cfa
265       nullptr,
266       // 0x3f DW_CFA_hi_user (Treat this as illegal)
267       nullptr,
268   };
269 };
270 
271 }  // namespace unwindstack
272