1 | //===-- DWARFCallFrameInfo.h ------------------------------------*- C++ -*-===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | |
9 | #ifndef LLDB_SYMBOL_DWARFCALLFRAMEINFO_H |
10 | #define LLDB_SYMBOL_DWARFCALLFRAMEINFO_H |
11 | |
12 | #include <map> |
13 | #include <mutex> |
14 | #include <optional> |
15 | |
16 | #include "lldb/Core/AddressRange.h" |
17 | #include "lldb/Core/dwarf.h" |
18 | #include "lldb/Symbol/ObjectFile.h" |
19 | #include "lldb/Symbol/UnwindPlan.h" |
20 | #include "lldb/Utility/Flags.h" |
21 | #include "lldb/Utility/RangeMap.h" |
22 | #include "lldb/Utility/VMRange.h" |
23 | #include "lldb/lldb-private.h" |
24 | |
25 | namespace lldb_private { |
26 | |
27 | // DWARFCallFrameInfo is a class which can read eh_frame and DWARF Call Frame |
28 | // Information FDEs. It stores little information internally. Only two APIs |
29 | // are exported - one to find the high/low pc values of a function given a text |
30 | // address via the information in the eh_frame / debug_frame, and one to |
31 | // generate an UnwindPlan based on the FDE in the eh_frame / debug_frame |
32 | // section. |
33 | |
34 | class DWARFCallFrameInfo { |
35 | public: |
36 | enum Type { EH, DWARF }; |
37 | |
38 | DWARFCallFrameInfo(ObjectFile &objfile, lldb::SectionSP §ion, Type type); |
39 | |
40 | ~DWARFCallFrameInfo() = default; |
41 | |
42 | // Locate an AddressRange that includes the provided Address in this object's |
43 | // eh_frame/debug_info Returns true if a range is found to cover that |
44 | // address. |
45 | bool GetAddressRange(Address addr, AddressRange &range); |
46 | |
47 | /// Return an UnwindPlan based on the call frame information encoded in the |
48 | /// FDE of this DWARFCallFrameInfo section. The returned plan will be valid |
49 | /// (at least) for the given address. |
50 | bool GetUnwindPlan(const Address &addr, UnwindPlan &unwind_plan); |
51 | |
52 | /// Return an UnwindPlan based on the call frame information encoded in the |
53 | /// FDE of this DWARFCallFrameInfo section. The returned plan will be valid |
54 | /// (at least) for some address in the given range. |
55 | bool GetUnwindPlan(const AddressRange &range, UnwindPlan &unwind_plan); |
56 | |
57 | typedef RangeVector<lldb::addr_t, uint32_t> FunctionAddressAndSizeVector; |
58 | |
59 | // Build a vector of file address and size for all functions in this Module |
60 | // based on the eh_frame FDE entries. |
61 | // |
62 | // The eh_frame information can be a useful source of file address and size |
63 | // of the functions in a Module. Often a binary's non-exported symbols are |
64 | // stripped before shipping so lldb won't know the start addr / size of many |
65 | // functions in the Module. But the eh_frame can help to give the addresses |
66 | // of these stripped symbols, at least. |
67 | // |
68 | // \param[out] function_info |
69 | // A vector provided by the caller is filled out. May be empty if no |
70 | // FDEs/no eh_frame |
71 | // is present in this Module. |
72 | |
73 | void |
74 | GetFunctionAddressAndSizeVector(FunctionAddressAndSizeVector &function_info); |
75 | |
76 | void ForEachFDEEntries( |
77 | const std::function<bool(lldb::addr_t, uint32_t, dw_offset_t)> &callback); |
78 | |
79 | private: |
80 | enum { CFI_AUG_MAX_SIZE = 8, = 8 }; |
81 | enum CFIVersion { |
82 | CFI_VERSION1 = 1, // DWARF v.2 |
83 | CFI_VERSION3 = 3, // DWARF v.3 |
84 | CFI_VERSION4 = 4 // DWARF v.4, v.5 |
85 | }; |
86 | |
87 | struct CIE { |
88 | dw_offset_t cie_offset; |
89 | uint8_t version; |
90 | char augmentation[CFI_AUG_MAX_SIZE]; // This is typically empty or very |
91 | // short. |
92 | uint8_t address_size = sizeof(uint32_t); // The size of a target address. |
93 | uint8_t segment_size = 0; // The size of a segment selector. |
94 | |
95 | uint32_t code_align; |
96 | int32_t data_align; |
97 | uint32_t return_addr_reg_num; |
98 | dw_offset_t inst_offset; // offset of CIE instructions in mCFIData |
99 | uint32_t inst_length; // length of CIE instructions in mCFIData |
100 | uint8_t ptr_encoding; |
101 | uint8_t lsda_addr_encoding; // The encoding of the LSDA address in the FDE |
102 | // augmentation data |
103 | lldb::addr_t personality_loc; // (file) address of the pointer to the |
104 | // personality routine |
105 | lldb_private::UnwindPlan::Row initial_row; |
106 | |
107 | CIE(dw_offset_t offset) |
108 | : cie_offset(offset), version(-1), code_align(0), data_align(0), |
109 | return_addr_reg_num(LLDB_INVALID_REGNUM), inst_offset(0), |
110 | inst_length(0), ptr_encoding(0), |
111 | lsda_addr_encoding(llvm::dwarf::DW_EH_PE_omit), |
112 | personality_loc(LLDB_INVALID_ADDRESS) {} |
113 | }; |
114 | |
115 | typedef std::shared_ptr<CIE> CIESP; |
116 | |
117 | typedef std::map<dw_offset_t, CIESP> cie_map_t; |
118 | |
119 | // Start address (file address), size, offset of FDE location used for |
120 | // finding an FDE for a given File address; the start address field is an |
121 | // offset into an individual Module. |
122 | typedef RangeDataVector<lldb::addr_t, uint32_t, dw_offset_t> FDEEntryMap; |
123 | |
124 | bool IsEHFrame() const; |
125 | |
126 | std::optional<FDEEntryMap::Entry> |
127 | GetFirstFDEEntryInRange(const AddressRange &range); |
128 | |
129 | void GetFDEIndex(); |
130 | |
131 | bool FDEToUnwindPlan(dw_offset_t offset, Address startaddr, |
132 | UnwindPlan &unwind_plan); |
133 | |
134 | const CIE *GetCIE(dw_offset_t cie_offset); |
135 | |
136 | void GetCFIData(); |
137 | |
138 | // Applies the specified DWARF opcode to the given row. This function handle |
139 | // the commands operates only on a single row (these are the ones what can |
140 | // appear both in |
141 | // CIE and in FDE). |
142 | // Returns true if the opcode is handled and false otherwise. |
143 | bool HandleCommonDwarfOpcode(uint8_t primary_opcode, uint8_t extended_opcode, |
144 | int32_t data_align, lldb::offset_t &offset, |
145 | UnwindPlan::Row &row); |
146 | |
147 | ObjectFile &m_objfile; |
148 | lldb::SectionSP m_section_sp; |
149 | Flags m_flags = 0; |
150 | cie_map_t m_cie_map; |
151 | |
152 | DataExtractor m_cfi_data; |
153 | bool m_cfi_data_initialized = false; // only copy the section into the DE once |
154 | |
155 | FDEEntryMap m_fde_index; |
156 | bool m_fde_index_initialized = false; // only scan the section for FDEs once |
157 | std::mutex m_fde_index_mutex; // and isolate the thread that does it |
158 | |
159 | Type m_type; |
160 | |
161 | CIESP |
162 | ParseCIE(const dw_offset_t cie_offset); |
163 | |
164 | lldb::RegisterKind GetRegisterKind() const { |
165 | return m_type == EH ? lldb::eRegisterKindEHFrame : lldb::eRegisterKindDWARF; |
166 | } |
167 | }; |
168 | |
169 | } // namespace lldb_private |
170 | |
171 | #endif // LLDB_SYMBOL_DWARFCALLFRAMEINFO_H |
172 | |