1 //===- Config.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 LLD_ELF_CONFIG_H 10 #define LLD_ELF_CONFIG_H 11 12 #include "lld/Common/ErrorHandler.h" 13 #include "llvm/ADT/MapVector.h" 14 #include "llvm/ADT/StringRef.h" 15 #include "llvm/ADT/StringSet.h" 16 #include "llvm/BinaryFormat/ELF.h" 17 #include "llvm/Support/CachePruning.h" 18 #include "llvm/Support/CodeGen.h" 19 #include "llvm/Support/Endian.h" 20 #include <atomic> 21 #include <vector> 22 23 namespace lld { 24 namespace elf { 25 26 class InputFile; 27 class InputSectionBase; 28 29 enum ELFKind { 30 ELFNoneKind, 31 ELF32LEKind, 32 ELF32BEKind, 33 ELF64LEKind, 34 ELF64BEKind 35 }; 36 37 // For --build-id. 38 enum class BuildIdKind { None, Fast, Md5, Sha1, Hexstring, Uuid }; 39 40 // For --discard-{all,locals,none}. 41 enum class DiscardPolicy { Default, All, Locals, None }; 42 43 // For --icf={none,safe,all}. 44 enum class ICFLevel { None, Safe, All }; 45 46 // For --strip-{all,debug}. 47 enum class StripPolicy { None, All, Debug }; 48 49 // For --unresolved-symbols. 50 enum class UnresolvedPolicy { ReportError, Warn, Ignore }; 51 52 // For --orphan-handling. 53 enum class OrphanHandlingPolicy { Place, Warn, Error }; 54 55 // For --sort-section and linkerscript sorting rules. 56 enum class SortSectionPolicy { Default, None, Alignment, Name, Priority }; 57 58 // For --target2 59 enum class Target2Policy { Abs, Rel, GotRel }; 60 61 // For tracking ARM Float Argument PCS 62 enum class ARMVFPArgKind { Default, Base, VFP, ToolChain }; 63 64 // For -z noseparate-code, -z separate-code and -z separate-loadable-segments. 65 enum class SeparateSegmentKind { None, Code, Loadable }; 66 67 struct SymbolVersion { 68 llvm::StringRef name; 69 bool isExternCpp; 70 bool hasWildcard; 71 }; 72 73 // This struct contains symbols version definition that 74 // can be found in version script if it is used for link. 75 struct VersionDefinition { 76 llvm::StringRef name; 77 uint16_t id; 78 std::vector<SymbolVersion> patterns; 79 }; 80 81 // This struct contains the global configuration for the linker. 82 // Most fields are direct mapping from the command line options 83 // and such fields have the same name as the corresponding options. 84 // Most fields are initialized by the driver. 85 struct Configuration { 86 uint8_t osabi = 0; 87 uint32_t andFeatures = 0; 88 llvm::CachePruningPolicy thinLTOCachePolicy; 89 llvm::StringMap<uint64_t> sectionStartMap; 90 llvm::StringRef chroot; 91 llvm::StringRef dynamicLinker; 92 llvm::StringRef dwoDir; 93 llvm::StringRef entry; 94 llvm::StringRef emulation; 95 llvm::StringRef fini; 96 llvm::StringRef init; 97 llvm::StringRef ltoAAPipeline; 98 llvm::StringRef ltoCSProfileFile; 99 llvm::StringRef ltoNewPmPasses; 100 llvm::StringRef ltoObjPath; 101 llvm::StringRef ltoSampleProfile; 102 llvm::StringRef mapFile; 103 llvm::StringRef outputFile; 104 llvm::StringRef optRemarksFilename; 105 llvm::StringRef optRemarksPasses; 106 llvm::StringRef optRemarksFormat; 107 llvm::StringRef progName; 108 llvm::StringRef printSymbolOrder; 109 llvm::StringRef soName; 110 llvm::StringRef sysroot; 111 llvm::StringRef thinLTOCacheDir; 112 llvm::StringRef thinLTOIndexOnlyArg; 113 std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace; 114 std::pair<llvm::StringRef, llvm::StringRef> thinLTOPrefixReplace; 115 std::string rpath; 116 std::vector<VersionDefinition> versionDefinitions; 117 std::vector<llvm::StringRef> auxiliaryList; 118 std::vector<llvm::StringRef> filterList; 119 std::vector<llvm::StringRef> searchPaths; 120 std::vector<llvm::StringRef> symbolOrderingFile; 121 std::vector<llvm::StringRef> undefined; 122 std::vector<SymbolVersion> dynamicList; 123 std::vector<uint8_t> buildIdVector; 124 llvm::MapVector<std::pair<const InputSectionBase *, const InputSectionBase *>, 125 uint64_t> 126 callGraphProfile; 127 bool allowMultipleDefinition; 128 bool allowShlibUndefined; 129 bool androidPackDynRelocs; 130 bool armHasBlx = false; 131 bool armHasMovtMovw = false; 132 bool armJ1J2BranchEncoding = false; 133 bool asNeeded = false; 134 bool bsymbolic; 135 bool bsymbolicFunctions; 136 bool callGraphProfileSort; 137 bool checkSections; 138 bool compressDebugSections; 139 bool cref; 140 bool defineCommon; 141 bool demangle = true; 142 bool dependentLibraries; 143 bool disableVerify; 144 bool ehFrameHdr; 145 bool emitLLVM; 146 bool emitRelocs; 147 bool enableNewDtags; 148 bool executeOnly; 149 bool exportDynamic; 150 bool fixCortexA53Errata843419; 151 bool fixCortexA8; 152 bool forceBTI; 153 bool formatBinary = false; 154 bool requireCET; 155 bool gcSections; 156 bool gdbIndex; 157 bool gnuHash = false; 158 bool gnuUnique; 159 bool hasDynamicList = false; 160 bool hasDynSymTab; 161 bool ignoreDataAddressEquality; 162 bool ignoreFunctionAddressEquality; 163 bool ltoCSProfileGenerate; 164 bool ltoDebugPassManager; 165 bool ltoNewPassManager; 166 bool mergeArmExidx; 167 bool mipsN32Abi = false; 168 bool nmagic; 169 bool noinhibitExec; 170 bool nostdlib; 171 bool oFormatBinary; 172 bool omagic; 173 bool optRemarksWithHotness; 174 bool pacPlt; 175 bool picThunk; 176 bool pie; 177 bool printGcSections; 178 bool printIcfSections; 179 bool relocatable; 180 bool relrPackDynRelocs; 181 bool saveTemps; 182 bool singleRoRx; 183 bool shared; 184 bool isStatic = false; 185 bool sysvHash = false; 186 bool target1Rel; 187 bool trace; 188 bool thinLTOEmitImportsFiles; 189 bool thinLTOIndexOnly; 190 bool tocOptimize; 191 bool undefinedVersion; 192 bool useAndroidRelrTags = false; 193 bool warnBackrefs; 194 bool warnCommon; 195 bool warnIfuncTextrel; 196 bool warnMissingEntry; 197 bool warnSymbolOrdering; 198 bool writeAddends; 199 bool zCombreloc; 200 bool zCopyreloc; 201 bool zExecstack; 202 bool zGlobal; 203 bool zHazardplt; 204 bool zIfuncNoplt; 205 bool zInitfirst; 206 bool zInterpose; 207 bool zKeepTextSectionPrefix; 208 bool zNodefaultlib; 209 bool zNodelete; 210 bool zNodlopen; 211 bool zNow; 212 bool zOrigin; 213 bool zRelro; 214 bool zRodynamic; 215 bool zText; 216 bool zRetpolineplt; 217 bool zWxneeded; 218 DiscardPolicy discard; 219 ICFLevel icf; 220 OrphanHandlingPolicy orphanHandling; 221 SortSectionPolicy sortSection; 222 StripPolicy strip; 223 UnresolvedPolicy unresolvedSymbols; 224 Target2Policy target2; 225 ARMVFPArgKind armVFPArgs = ARMVFPArgKind::Default; 226 BuildIdKind buildId = BuildIdKind::None; 227 SeparateSegmentKind zSeparate; 228 ELFKind ekind = ELFNoneKind; 229 uint16_t emachine = llvm::ELF::EM_NONE; 230 llvm::Optional<uint64_t> imageBase; 231 uint64_t commonPageSize; 232 uint64_t maxPageSize; 233 uint64_t mipsGotSize; 234 uint64_t zStackSize; 235 unsigned ltoPartitions; 236 unsigned ltoo; 237 unsigned optimize; 238 unsigned thinLTOJobs; 239 int32_t splitStackAdjustSize; 240 241 // The following config options do not directly correspond to any 242 // particualr command line options. 243 244 // True if we need to pass through relocations in input files to the 245 // output file. Usually false because we consume relocations. 246 bool copyRelocs; 247 248 // True if the target is ELF64. False if ELF32. 249 bool is64; 250 251 // True if the target is little-endian. False if big-endian. 252 bool isLE; 253 254 // endianness::little if isLE is true. endianness::big otherwise. 255 llvm::support::endianness endianness; 256 257 // True if the target is the little-endian MIPS64. 258 // 259 // The reason why we have this variable only for the MIPS is because 260 // we use this often. Some ELF headers for MIPS64EL are in a 261 // mixed-endian (which is horrible and I'd say that's a serious spec 262 // bug), and we need to know whether we are reading MIPS ELF files or 263 // not in various places. 264 // 265 // (Note that MIPS64EL is not a typo for MIPS64LE. This is the official 266 // name whatever that means. A fun hypothesis is that "EL" is short for 267 // little-endian written in the little-endian order, but I don't know 268 // if that's true.) 269 bool isMips64EL; 270 271 // True if we need to set the DF_STATIC_TLS flag to an output file, 272 // which works as a hint to the dynamic loader that the file contains 273 // code compiled with the static TLS model. The thread-local variable 274 // compiled with the static TLS model is faster but less flexible, and 275 // it may not be loaded using dlopen(). 276 // 277 // We set this flag to true when we see a relocation for the static TLS 278 // model. Once this becomes true, it will never become false. 279 // 280 // Since the flag is updated by multi-threaded code, we use std::atomic. 281 // (Writing to a variable is not considered thread-safe even if the 282 // variable is boolean and we always set the same value from all threads.) 283 std::atomic<bool> hasStaticTlsModel{false}; 284 285 // Holds set of ELF header flags for the target. 286 uint32_t eflags = 0; 287 288 // The ELF spec defines two types of relocation table entries, RELA and 289 // REL. RELA is a triplet of (offset, info, addend) while REL is a 290 // tuple of (offset, info). Addends for REL are implicit and read from 291 // the location where the relocations are applied. So, REL is more 292 // compact than RELA but requires a bit of more work to process. 293 // 294 // (From the linker writer's view, this distinction is not necessary. 295 // If the ELF had chosen whichever and sticked with it, it would have 296 // been easier to write code to process relocations, but it's too late 297 // to change the spec.) 298 // 299 // Each ABI defines its relocation type. IsRela is true if target 300 // uses RELA. As far as we know, all 64-bit ABIs are using RELA. A 301 // few 32-bit ABIs are using RELA too. 302 bool isRela; 303 304 // True if we are creating position-independent code. 305 bool isPic; 306 307 // 4 for ELF32, 8 for ELF64. 308 int wordsize; 309 }; 310 311 // The only instance of Configuration struct. 312 extern Configuration *config; 313 314 // The first two elements of versionDefinitions represent VER_NDX_LOCAL and 315 // VER_NDX_GLOBAL. This helper returns other elements. 316 static inline ArrayRef<VersionDefinition> namedVersionDefs() { 317 return llvm::makeArrayRef(config->versionDefinitions).slice(2); 318 } 319 320 static inline void errorOrWarn(const Twine &msg) { 321 if (!config->noinhibitExec) 322 error(msg); 323 else 324 warn(msg); 325 } 326 } // namespace elf 327 } // namespace lld 328 329 #endif 330