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, 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 CIECIE107 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 GetRegisterKind()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