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
25namespace 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
34class DWARFCallFrameInfo {
35public:
36 enum Type { EH, DWARF };
37
38 DWARFCallFrameInfo(ObjectFile &objfile, lldb::SectionSP &section, 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
79private:
80 enum { CFI_AUG_MAX_SIZE = 8, CFI_HEADER_SIZE = 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

source code of lldb/include/lldb/Symbol/DWARFCallFrameInfo.h