1 //===- FunctionInfo.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 LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H 10 #define LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H 11 12 #include "llvm/ADT/Optional.h" 13 #include "llvm/DebugInfo/GSYM/ExtractRanges.h" 14 #include "llvm/DebugInfo/GSYM/InlineInfo.h" 15 #include "llvm/DebugInfo/GSYM/LineTable.h" 16 #include "llvm/DebugInfo/GSYM/LookupResult.h" 17 #include "llvm/DebugInfo/GSYM/StringTable.h" 18 #include <cstdint> 19 #include <tuple> 20 21 namespace llvm { 22 class raw_ostream; 23 24 namespace gsym { 25 26 class GsymReader; 27 /// Function information in GSYM files encodes information for one contiguous 28 /// address range. If a function has discontiguous address ranges, they will 29 /// need to be encoded using multiple FunctionInfo objects. 30 /// 31 /// ENCODING 32 /// 33 /// The function information gets the function start address as an argument 34 /// to the FunctionInfo::decode(...) function. This information is calculated 35 /// from the GSYM header and an address offset from the GSYM address offsets 36 /// table. The encoded FunctionInfo information must be aligned to a 4 byte 37 /// boundary. 38 /// 39 /// The encoded data for a FunctionInfo starts with fixed data that all 40 /// function info objects have: 41 /// 42 /// ENCODING NAME DESCRIPTION 43 /// ========= =========== ==================================================== 44 /// uint32_t Size The size in bytes of this function. 45 /// uint32_t Name The string table offset of the function name. 46 /// 47 /// The optional data in a FunctionInfo object follows this fixed information 48 /// and consists of a stream of tuples that consist of: 49 /// 50 /// ENCODING NAME DESCRIPTION 51 /// ========= =========== ==================================================== 52 /// uint32_t InfoType An "InfoType" enumeration that describes the type 53 /// of optional data that is encoded. 54 /// uint32_t InfoLength The size in bytes of the encoded data that 55 /// immediately follows this length if this value is 56 /// greater than zero. 57 /// uint8_t[] InfoData Encoded bytes that represent the data for the 58 /// "InfoType". These bytes are only present if 59 /// "InfoLength" is greater than zero. 60 /// 61 /// The "InfoType" is an enumeration: 62 /// 63 /// enum InfoType { 64 /// EndOfList = 0u, 65 /// LineTableInfo = 1u, 66 /// InlineInfo = 2u 67 /// }; 68 /// 69 /// This stream of tuples is terminated by a "InfoType" whose value is 70 /// InfoType::EndOfList and a zero for "InfoLength". This signifies the end of 71 /// the optional information list. This format allows us to add new optional 72 /// information data to a FunctionInfo object over time and allows older 73 /// clients to still parse the format and skip over any data that they don't 74 /// understand or want to parse. 75 /// 76 /// So the function information encoding essientially looks like: 77 /// 78 /// struct { 79 /// uint32_t Size; 80 /// uint32_t Name; 81 /// struct { 82 /// uint32_t InfoType; 83 /// uint32_t InfoLength; 84 /// uint8_t InfoData[InfoLength]; 85 /// }[N]; 86 /// } 87 /// 88 /// Where "N" is the number of tuples. 89 struct FunctionInfo { 90 AddressRange Range; 91 uint32_t Name; ///< String table offset in the string table. 92 llvm::Optional<LineTable> OptLineTable; 93 llvm::Optional<InlineInfo> Inline; 94 95 FunctionInfo(uint64_t Addr = 0, uint64_t Size = 0, uint32_t N = 0) 96 : Range(Addr, Addr + Size), Name(N) {} 97 98 /// Query if a FunctionInfo has rich debug info. 99 /// 100 /// \returns A bool that indicates if this object has something else than 101 /// range and name. When converting information from a symbol table and from 102 /// debug info, we might end up with multiple FunctionInfo objects for the 103 /// same range and we need to be able to tell which one is the better object 104 /// to use. 105 bool hasRichInfo() const { return OptLineTable || Inline; } 106 107 /// Query if a FunctionInfo object is valid. 108 /// 109 /// Address and size can be zero and there can be no line entries for a 110 /// symbol so the only indication this entry is valid is if the name is 111 /// not zero. This can happen when extracting information from symbol 112 /// tables that do not encode symbol sizes. In that case only the 113 /// address and name will be filled in. 114 /// 115 /// \returns A boolean indicating if this FunctionInfo is valid. 116 bool isValid() const { 117 return Name != 0; 118 } 119 120 /// Decode an object from a binary data stream. 121 /// 122 /// \param Data The binary stream to read the data from. This object must 123 /// have the data for the object starting at offset zero. The data 124 /// can contain more data than needed. 125 /// 126 /// \param BaseAddr The FunctionInfo's start address and will be used as the 127 /// base address when decoding any contained information like the line table 128 /// and the inline info. 129 /// 130 /// \returns An FunctionInfo or an error describing the issue that was 131 /// encountered during decoding. 132 static llvm::Expected<FunctionInfo> decode(DataExtractor &Data, 133 uint64_t BaseAddr); 134 135 /// Encode this object into FileWriter stream. 136 /// 137 /// \param O The binary stream to write the data to at the current file 138 /// position. 139 /// 140 /// \returns An error object that indicates failure or the offset of the 141 /// function info that was successfully written into the stream. 142 llvm::Expected<uint64_t> encode(FileWriter &O) const; 143 144 145 /// Lookup an address within a FunctionInfo object's data stream. 146 /// 147 /// Instead of decoding an entire FunctionInfo object when doing lookups, 148 /// we can decode only the information we need from the FunctionInfo's data 149 /// for the specific address. The lookup result information is returned as 150 /// a LookupResult. 151 /// 152 /// \param Data The binary stream to read the data from. This object must 153 /// have the data for the object starting at offset zero. The data 154 /// can contain more data than needed. 155 /// 156 /// \param GR The GSYM reader that contains the string and file table that 157 /// will be used to fill in information in the returned result. 158 /// 159 /// \param FuncAddr The function start address decoded from the GsymReader. 160 /// 161 /// \param Addr The address to lookup. 162 /// 163 /// \returns An LookupResult or an error describing the issue that was 164 /// encountered during decoding. An error should only be returned if the 165 /// address is not contained in the FunctionInfo or if the data is corrupted. 166 static llvm::Expected<LookupResult> lookup(DataExtractor &Data, 167 const GsymReader &GR, 168 uint64_t FuncAddr, 169 uint64_t Addr); 170 171 uint64_t startAddress() const { return Range.start(); } 172 uint64_t endAddress() const { return Range.end(); } 173 uint64_t size() const { return Range.size(); } 174 175 void clear() { 176 Range = {0, 0}; 177 Name = 0; 178 OptLineTable = None; 179 Inline = None; 180 } 181 }; 182 183 inline bool operator==(const FunctionInfo &LHS, const FunctionInfo &RHS) { 184 return LHS.Range == RHS.Range && LHS.Name == RHS.Name && 185 LHS.OptLineTable == RHS.OptLineTable && LHS.Inline == RHS.Inline; 186 } 187 inline bool operator!=(const FunctionInfo &LHS, const FunctionInfo &RHS) { 188 return !(LHS == RHS); 189 } 190 /// This sorting will order things consistently by address range first, but then 191 /// followed by inlining being valid and line tables. We might end up with a 192 /// FunctionInfo from debug info that will have the same range as one from the 193 /// symbol table, but we want to quickly be able to sort and use the best version 194 /// when creating the final GSYM file. 195 inline bool operator<(const FunctionInfo &LHS, const FunctionInfo &RHS) { 196 // First sort by address range 197 if (LHS.Range != RHS.Range) 198 return LHS.Range < RHS.Range; 199 200 // Then sort by inline 201 if (LHS.Inline.has_value() != RHS.Inline.has_value()) 202 return RHS.Inline.has_value(); 203 204 return LHS.OptLineTable < RHS.OptLineTable; 205 } 206 207 raw_ostream &operator<<(raw_ostream &OS, const FunctionInfo &R); 208 209 } // namespace gsym 210 } // namespace llvm 211 212 #endif // LLVM_DEBUGINFO_GSYM_FUNCTIONINFO_H 213