LLDB  mainline
DWARFCallFrameInfo.h
Go to the documentation of this file.
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 liblldb_DWARFCallFrameInfo_h_
10 #define liblldb_DWARFCallFrameInfo_h_
11 
12 #include <map>
13 #include <mutex>
14 
15 #include "lldb/Core/AddressRange.h"
16 #include "lldb/Core/dwarf.h"
17 #include "lldb/Symbol/ObjectFile.h"
18 #include "lldb/Symbol/UnwindPlan.h"
19 #include "lldb/Utility/Flags.h"
20 #include "lldb/Utility/RangeMap.h"
21 #include "lldb/Utility/VMRange.h"
22 #include "lldb/lldb-private.h"
23 
24 namespace lldb_private {
25 
26 // DWARFCallFrameInfo is a class which can read eh_frame and DWARF Call Frame
27 // Information FDEs. It stores little information internally. Only two APIs
28 // are exported - one to find the high/low pc values of a function given a text
29 // address via the information in the eh_frame / debug_frame, and one to
30 // generate an UnwindPlan based on the FDE in the eh_frame / debug_frame
31 // section.
32 
34 public:
35  enum Type { EH, DWARF };
36 
37  DWARFCallFrameInfo(ObjectFile &objfile, lldb::SectionSP &section, Type type);
38 
39  ~DWARFCallFrameInfo() = default;
40 
41  // Locate an AddressRange that includes the provided Address in this object's
42  // eh_frame/debug_info Returns true if a range is found to cover that
43  // address.
44  bool GetAddressRange(Address addr, AddressRange &range);
45 
46  /// Return an UnwindPlan based on the call frame information encoded in the
47  /// FDE of this DWARFCallFrameInfo section. The returned plan will be valid
48  /// (at least) for the given address.
49  bool GetUnwindPlan(const Address &addr, UnwindPlan &unwind_plan);
50 
51  /// Return an UnwindPlan based on the call frame information encoded in the
52  /// FDE of this DWARFCallFrameInfo section. The returned plan will be valid
53  /// (at least) for some address in the given range.
54  bool GetUnwindPlan(const AddressRange &range, UnwindPlan &unwind_plan);
55 
57 
58  // Build a vector of file address and size for all functions in this Module
59  // based on the eh_frame FDE entries.
60  //
61  // The eh_frame information can be a useful source of file address and size
62  // of the functions in a Module. Often a binary's non-exported symbols are
63  // stripped before shipping so lldb won't know the start addr / size of many
64  // functions in the Module. But the eh_frame can help to give the addresses
65  // of these stripped symbols, at least.
66  //
67  // \param[out] function_info
68  // A vector provided by the caller is filled out. May be empty if no
69  // FDEs/no eh_frame
70  // is present in this Module.
71 
72  void
73  GetFunctionAddressAndSizeVector(FunctionAddressAndSizeVector &function_info);
74 
75  void ForEachFDEEntries(
76  const std::function<bool(lldb::addr_t, uint32_t, dw_offset_t)> &callback);
77 
78 private:
79  enum { CFI_AUG_MAX_SIZE = 8, CFI_HEADER_SIZE = 8 };
80  enum CFIVersion {
81  CFI_VERSION1 = 1, // DWARF v.2
82  CFI_VERSION3 = 3, // DWARF v.3
83  CFI_VERSION4 = 4 // DWARF v.4, v.5
84  };
85 
86  struct CIE {
87  dw_offset_t cie_offset;
88  uint8_t version;
89  char augmentation[CFI_AUG_MAX_SIZE]; // This is typically empty or very
90  // short.
91  uint8_t address_size = sizeof(uint32_t); // The size of a target address.
92  uint8_t segment_size = 0; // The size of a segment selector.
93 
94  uint32_t code_align;
95  int32_t data_align;
96  uint32_t return_addr_reg_num;
97  dw_offset_t inst_offset; // offset of CIE instructions in mCFIData
98  uint32_t inst_length; // length of CIE instructions in mCFIData
99  uint8_t ptr_encoding;
100  uint8_t lsda_addr_encoding; // The encoding of the LSDA address in the FDE
101  // augmentation data
102  lldb::addr_t personality_loc; // (file) address of the pointer to the
103  // personality routine
104  lldb_private::UnwindPlan::Row initial_row;
105 
106  CIE(dw_offset_t offset)
107  : cie_offset(offset), version(-1), code_align(0), data_align(0),
108  return_addr_reg_num(LLDB_INVALID_REGNUM), inst_offset(0),
109  inst_length(0), ptr_encoding(0), lsda_addr_encoding(DW_EH_PE_omit),
110  personality_loc(LLDB_INVALID_ADDRESS), initial_row() {}
111  };
112 
113  typedef std::shared_ptr<CIE> CIESP;
114 
115  typedef std::map<dw_offset_t, CIESP> cie_map_t;
116 
117  // Start address (file address), size, offset of FDE location used for
118  // finding an FDE for a given File address; the start address field is an
119  // offset into an individual Module.
121 
122  bool IsEHFrame() const;
123 
124  llvm::Optional<FDEEntryMap::Entry>
125  GetFirstFDEEntryInRange(const AddressRange &range);
126 
127  void GetFDEIndex();
128 
129  bool FDEToUnwindPlan(uint32_t offset, Address startaddr,
130  UnwindPlan &unwind_plan);
131 
132  const CIE *GetCIE(dw_offset_t cie_offset);
133 
134  void GetCFIData();
135 
136  // Applies the specified DWARF opcode to the given row. This function handle
137  // the commands operates only on a single row (these are the ones what can
138  // appear both in
139  // CIE and in FDE).
140  // Returns true if the opcode is handled and false otherwise.
141  bool HandleCommonDwarfOpcode(uint8_t primary_opcode, uint8_t extended_opcode,
142  int32_t data_align, lldb::offset_t &offset,
143  UnwindPlan::Row &row);
144 
145  ObjectFile &m_objfile;
146  lldb::SectionSP m_section_sp;
147  Flags m_flags = 0;
148  cie_map_t m_cie_map;
149 
150  DataExtractor m_cfi_data;
151  bool m_cfi_data_initialized = false; // only copy the section into the DE once
152 
153  FDEEntryMap m_fde_index;
154  bool m_fde_index_initialized = false; // only scan the section for FDEs once
155  std::mutex m_fde_index_mutex; // and isolate the thread that does it
156 
157  Type m_type;
158 
159  CIESP
160  ParseCIE(const uint32_t cie_offset);
161 
162  lldb::RegisterKind GetRegisterKind() const {
164  }
165 };
166 
167 } // namespace lldb_private
168 
169 #endif // liblldb_DWARFCallFrameInfo_h_
An data extractor class.
Definition: DataExtractor.h:47
Enumerations for broadcasting.
Definition: SBLaunchInfo.h:14
A plug-in interface definition class for object file parsers.
Definition: ObjectFile.h:58
#define LLDB_INVALID_ADDRESS
Invalid value definitions.
Definition: lldb-defines.h:85
uint64_t offset_t
Definition: lldb-types.h:87
void ForEachFDEEntries(const std::function< bool(lldb::addr_t, uint32_t, dw_offset_t)> &callback)
DWARFCallFrameInfo(ObjectFile &objfile, lldb::SectionSP &section, Type type)
A section + offset based address class.
Definition: Address.h:80
bool GetUnwindPlan(const Address &addr, UnwindPlan &unwind_plan)
Return an UnwindPlan based on the call frame information encoded in the FDE of this DWARFCallFrameInf...
void GetFunctionAddressAndSizeVector(FunctionAddressAndSizeVector &function_info)
A class to manage flags.
Definition: Flags.h:22
uint64_t addr_t
Definition: lldb-types.h:83
A section + offset based address range class.
Definition: AddressRange.h:32
RangeVector< lldb::addr_t, uint32_t > FunctionAddressAndSizeVector
bool GetAddressRange(Address addr, AddressRange &range)
#define LLDB_INVALID_REGNUM
Definition: lldb-defines.h:90