lld/ELF/Config.h

   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/CachedHashString.h"
  14 #include "llvm/ADT/DenseSet.h"
  15 #include "llvm/ADT/MapVector.h"
  16 #include "llvm/ADT/SetVector.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/ADT/StringSet.h"
  19 #include "llvm/BinaryFormat/ELF.h"
  20 #include "llvm/Support/CachePruning.h"
  21 #include "llvm/Support/CodeGen.h"
  22 #include "llvm/Support/Endian.h"
  23 #include "llvm/Support/GlobPattern.h"
  24 #include "llvm/Support/PrettyStackTrace.h"
  25 #include <atomic>
  26 #include <memory>
  27 #include <vector>
  28
  29 namespace lld {
  30 namespace elf {
  31
  32 class InputFile;
  33 class BinaryFile;
  34 class BitcodeFile;
  35 class ELFFileBase;
  36 class SharedFile;
  37 class InputSectionBase;
  38 class Symbol;
  39
  40 enum ELFKind : uint8_t {
  41   ELFNoneKind,
  42   ELF32LEKind,
  43   ELF32BEKind,
  44   ELF64LEKind,
  45   ELF64BEKind
  46 };
  47
  48 // For -Bno-symbolic, -Bsymbolic-non-weak-functions, -Bsymbolic-functions,
  49 // -Bsymbolic.
  50 enum class BsymbolicKind { None, NonWeakFunctions, Functions, All };
  51
  52 // For --build-id.
  53 enum class BuildIdKind { None, Fast, Md5, Sha1, Hexstring, Uuid };
  54
  55 // For --discard-{all,locals,none}.
  56 enum class DiscardPolicy { Default, All, Locals, None };
  57
  58 // For --icf={none,safe,all}.
  59 enum class ICFLevel { None, Safe, All };
  60
  61 // For --strip-{all,debug}.
  62 enum class StripPolicy { None, All, Debug };
  63
  64 // For --unresolved-symbols.
  65 enum class UnresolvedPolicy { ReportError, Warn, Ignore };
  66
  67 // For --orphan-handling.
  68 enum class OrphanHandlingPolicy { Place, Warn, Error };
  69
  70 // For --sort-section and linkerscript sorting rules.
  71 enum class SortSectionPolicy { Default, None, Alignment, Name, Priority };
  72
  73 // For --target2
  74 enum class Target2Policy { Abs, Rel, GotRel };
  75
  76 // For tracking ARM Float Argument PCS
  77 enum class ARMVFPArgKind { Default, Base, VFP, ToolChain };
  78
  79 // For -z noseparate-code, -z separate-code and -z separate-loadable-segments.
  80 enum class SeparateSegmentKind { None, Code, Loadable };
  81
  82 // For -z *stack
  83 enum class GnuStackKind { None, Exec, NoExec };
  84
  85 struct SymbolVersion {
  86   llvm::StringRef name;
  87   bool isExternCpp;
  88   bool hasWildcard;
  89 };
  90
  91 // This struct contains symbols version definition that
  92 // can be found in version script if it is used for link.
  93 struct VersionDefinition {
  94   llvm::StringRef name;
  95   uint16_t id;
  96   SmallVector<SymbolVersion, 0> nonLocalPatterns;
  97   SmallVector<SymbolVersion, 0> localPatterns;
  98 };
  99
 100 // This struct contains the global configuration for the linker.
 101 // Most fields are direct mapping from the command line options
 102 // and such fields have the same name as the corresponding options.
 103 // Most fields are initialized by the driver.
 104 struct Configuration {
 105   uint8_t osabi = 0;
 106   uint32_t andFeatures = 0;
 107   llvm::CachePruningPolicy thinLTOCachePolicy;
 108   llvm::SetVector<llvm::CachedHashString> dependencyFiles; // for --dependency-file
 109   llvm::StringMap<uint64_t> sectionStartMap;
 110   llvm::StringRef bfdname;
 111   llvm::StringRef chroot;
 112   llvm::StringRef dependencyFile;
 113   llvm::StringRef dwoDir;
 114   llvm::StringRef dynamicLinker;
 115   llvm::StringRef entry;
 116   llvm::StringRef emulation;
 117   llvm::StringRef fini;
 118   llvm::StringRef init;
 119   llvm::StringRef ltoAAPipeline;
 120   llvm::StringRef ltoCSProfileFile;
 121   llvm::StringRef ltoNewPmPasses;
 122   llvm::StringRef ltoObjPath;
 123   llvm::StringRef ltoSampleProfile;
 124   llvm::StringRef mapFile;
 125   llvm::StringRef outputFile;
 126   llvm::StringRef optRemarksFilename;
 127   llvm::Optional<uint64_t> optRemarksHotnessThreshold = 0;
 128   llvm::StringRef optRemarksPasses;
 129   llvm::StringRef optRemarksFormat;
 130   llvm::StringRef optStatsFilename;
 131   llvm::StringRef progName;
 132   llvm::StringRef printArchiveStats;
 133   llvm::StringRef printSymbolOrder;
 134   llvm::StringRef soName;
 135   llvm::StringRef sysroot;
 136   llvm::StringRef thinLTOCacheDir;
 137   llvm::StringRef thinLTOIndexOnlyArg;
 138   llvm::StringRef whyExtract;
 139   StringRef zBtiReport = "none";
 140   StringRef zCetReport = "none";
 141   llvm::StringRef ltoBasicBlockSections;
 142   std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace;
 143   std::pair<llvm::StringRef, llvm::StringRef> thinLTOPrefixReplace;
 144   std::string rpath;
 145   llvm::SmallVector<VersionDefinition, 0> versionDefinitions;
 146   llvm::SmallVector<llvm::StringRef, 0> auxiliaryList;
 147   llvm::SmallVector<llvm::StringRef, 0> filterList;
 148   llvm::SmallVector<llvm::StringRef, 0> passPlugins;
 149   llvm::SmallVector<llvm::StringRef, 0> searchPaths;
 150   llvm::SmallVector<llvm::StringRef, 0> symbolOrderingFile;
 151   llvm::SmallVector<llvm::StringRef, 0> thinLTOModulesToCompile;
 152   llvm::SmallVector<llvm::StringRef, 0> undefined;
 153   llvm::SmallVector<SymbolVersion, 0> dynamicList;
 154   llvm::SmallVector<uint8_t, 0> buildIdVector;
 155   llvm::MapVector<std::pair<const InputSectionBase *, const InputSectionBase *>,
 156                   uint64_t>
 157       callGraphProfile;
 158   bool allowMultipleDefinition;
 159   bool androidPackDynRelocs = false;
 160   bool armHasBlx = false;
 161   bool armHasMovtMovw = false;
 162   bool armJ1J2BranchEncoding = false;
 163   bool asNeeded = false;
 164   BsymbolicKind bsymbolic = BsymbolicKind::None;
 165   bool callGraphProfileSort;
 166   bool checkSections;
 167   bool checkDynamicRelocs;
 168   bool compressDebugSections;
 169   bool cref;
 170   llvm::SmallVector<std::pair<llvm::GlobPattern, uint64_t>, 0>
 171       deadRelocInNonAlloc;
 172   bool demangle = true;
 173   bool dependentLibraries;
 174   bool disableVerify;
 175   bool ehFrameHdr;
 176   bool emitLLVM;
 177   bool emitRelocs;
 178   bool enableNewDtags;
 179   bool executeOnly;
 180   bool exportDynamic;
 181   bool fixCortexA53Errata843419;
 182   bool fixCortexA8;
 183   bool formatBinary = false;
 184   bool fortranCommon;
 185   bool gcSections;
 186   bool gdbIndex;
 187   bool gnuHash = false;
 188   bool gnuUnique;
 189   bool hasDynSymTab;
 190   bool ignoreDataAddressEquality;
 191   bool ignoreFunctionAddressEquality;
 192   bool ltoCSProfileGenerate;
 193   bool ltoPGOWarnMismatch;
 194   bool ltoDebugPassManager;
 195   bool ltoEmitAsm;
 196   bool ltoUniqueBasicBlockSectionNames;
 197   bool ltoWholeProgramVisibility;
 198   bool mergeArmExidx;
 199   bool mipsN32Abi = false;
 200   bool mmapOutputFile;
 201   bool nmagic;
 202   bool noDynamicLinker = false;
 203   bool noinhibitExec;
 204   bool nostdlib;
 205   bool oFormatBinary;
 206   bool omagic;
 207   bool opaquePointers;
 208   bool optEB = false;
 209   bool optEL = false;
 210   bool optimizeBBJumps;
 211   bool optRemarksWithHotness;
 212   bool picThunk;
 213   bool pie;
 214   bool printGcSections;
 215   bool printIcfSections;
 216   bool relax;
 217   bool relocatable;
 218   bool relrGlibc = false;
 219   bool relrPackDynRelocs = false;
 220   llvm::DenseSet<llvm::StringRef> saveTempsArgs;
 221   llvm::SmallVector<std::pair<llvm::GlobPattern, uint32_t>, 0> shuffleSections;
 222   bool singleRoRx;
 223   bool shared;
 224   bool symbolic;
 225   bool isStatic = false;
 226   bool sysvHash = false;
 227   bool target1Rel;
 228   bool trace;
 229   bool thinLTOEmitImportsFiles;
 230   bool thinLTOEmitIndexFiles;
 231   bool thinLTOIndexOnly;
 232   bool timeTraceEnabled;
 233   bool tocOptimize;
 234   bool pcRelOptimize;
 235   bool undefinedVersion;
 236   bool unique;
 237   bool useAndroidRelrTags = false;
 238   bool warnBackrefs;
 239   llvm::SmallVector<llvm::GlobPattern, 0> warnBackrefsExclude;
 240   bool warnCommon;
 241   bool warnMissingEntry;
 242   bool warnSymbolOrdering;
 243   bool writeAddends;
 244   bool zCombreloc;
 245   bool zCopyreloc;
 246   bool zForceBti;
 247   bool zForceIbt;
 248   bool zGlobal;
 249   bool zHazardplt;
 250   bool zIfuncNoplt;
 251   bool zInitfirst;
 252   bool zInterpose;
 253   bool zKeepTextSectionPrefix;
 254   bool zNodefaultlib;
 255   bool zNodelete;
 256   bool zNodlopen;
 257   bool zNow;
 258   bool zOrigin;
 259   bool zPacPlt;
 260   bool zRelro;
 261   bool zRodynamic;
 262   bool zShstk;
 263   bool zStartStopGC;
 264   uint8_t zStartStopVisibility;
 265   bool zText;
 266   bool zRetpolineplt;
 267   bool zWxneeded;
 268   DiscardPolicy discard;
 269   GnuStackKind zGnustack;
 270   ICFLevel icf;
 271   OrphanHandlingPolicy orphanHandling;
 272   SortSectionPolicy sortSection;
 273   StripPolicy strip;
 274   UnresolvedPolicy unresolvedSymbols;
 275   UnresolvedPolicy unresolvedSymbolsInShlib;
 276   Target2Policy target2;
 277   bool power10Stubs;
 278   ARMVFPArgKind armVFPArgs = ARMVFPArgKind::Default;
 279   BuildIdKind buildId = BuildIdKind::None;
 280   SeparateSegmentKind zSeparate;
 281   ELFKind ekind = ELFNoneKind;
 282   uint16_t emachine = llvm::ELF::EM_NONE;
 283   llvm::Optional<uint64_t> imageBase;
 284   uint64_t commonPageSize;
 285   uint64_t maxPageSize;
 286   uint64_t mipsGotSize;
 287   uint64_t zStackSize;
 288   unsigned ltoPartitions;
 289   unsigned ltoo;
 290   unsigned optimize;
 291   StringRef thinLTOJobs;
 292   unsigned timeTraceGranularity;
 293   int32_t splitStackAdjustSize;
 294   StringRef packageMetadata;
 295
 296   // The following config options do not directly correspond to any
 297   // particular command line options.
 298
 299   // True if we need to pass through relocations in input files to the
 300   // output file. Usually false because we consume relocations.
 301   bool copyRelocs;
 302
 303   // True if the target is ELF64. False if ELF32.
 304   bool is64;
 305
 306   // True if the target is little-endian. False if big-endian.
 307   bool isLE;
 308
 309   // endianness::little if isLE is true. endianness::big otherwise.
 310   llvm::support::endianness endianness;
 311
 312   // True if the target is the little-endian MIPS64.
 313   //
 314   // The reason why we have this variable only for the MIPS is because
 315   // we use this often.  Some ELF headers for MIPS64EL are in a
 316   // mixed-endian (which is horrible and I'd say that's a serious spec
 317   // bug), and we need to know whether we are reading MIPS ELF files or
 318   // not in various places.
 319   //
 320   // (Note that MIPS64EL is not a typo for MIPS64LE. This is the official
 321   // name whatever that means. A fun hypothesis is that "EL" is short for
 322   // little-endian written in the little-endian order, but I don't know
 323   // if that's true.)
 324   bool isMips64EL;
 325
 326   // True if we need to reserve two .got entries for local-dynamic TLS model.
 327   bool needsTlsLd = false;
 328
 329   // True if we need to set the DF_STATIC_TLS flag to an output file, which
 330   // works as a hint to the dynamic loader that the shared object contains code
 331   // compiled with the initial-exec TLS model.
 332   bool hasTlsIe = false;
 333
 334   // Holds set of ELF header flags for the target.
 335   uint32_t eflags = 0;
 336
 337   // The ELF spec defines two types of relocation table entries, RELA and
 338   // REL. RELA is a triplet of (offset, info, addend) while REL is a
 339   // tuple of (offset, info). Addends for REL are implicit and read from
 340   // the location where the relocations are applied. So, REL is more
 341   // compact than RELA but requires a bit of more work to process.
 342   //
 343   // (From the linker writer's view, this distinction is not necessary.
 344   // If the ELF had chosen whichever and sticked with it, it would have
 345   // been easier to write code to process relocations, but it's too late
 346   // to change the spec.)
 347   //
 348   // Each ABI defines its relocation type. IsRela is true if target
 349   // uses RELA. As far as we know, all 64-bit ABIs are using RELA. A
 350   // few 32-bit ABIs are using RELA too.
 351   bool isRela;
 352
 353   // True if we are creating position-independent code.
 354   bool isPic;
 355
 356   // 4 for ELF32, 8 for ELF64.
 357   int wordsize;
 358
 359   // Mode of MTE to write to the ELF note. Should be one of NT_MEMTAG_ASYNC (for
 360   // async), NT_MEMTAG_SYNC (for sync), or NT_MEMTAG_LEVEL_NONE (for none). If
 361   // async or sync is enabled, write the ELF note specifying the default MTE
 362   // mode.
 363   int androidMemtagMode;
 364   // Signal to the dynamic loader to enable heap MTE.
 365   bool androidMemtagHeap;
 366   // Signal to the dynamic loader that this binary expects stack MTE. Generally,
 367   // this means to map the primary and thread stacks as PROT_MTE. Note: This is
 368   // not supported on Android 11 & 12.
 369   bool androidMemtagStack;
 370 };
 371
 372 // The only instance of Configuration struct.
 373 extern std::unique_ptr<Configuration> config;
 374
 375 struct DuplicateSymbol {
 376   const Symbol *sym;
 377   const InputFile *file;
 378   InputSectionBase *section;
 379   uint64_t value;
 380 };
 381
 382 struct Ctx {
 383   SmallVector<std::unique_ptr<MemoryBuffer>> memoryBuffers;
 384   SmallVector<ELFFileBase *, 0> objectFiles;
 385   SmallVector<SharedFile *, 0> sharedFiles;
 386   SmallVector<BinaryFile *, 0> binaryFiles;
 387   SmallVector<BitcodeFile *, 0> bitcodeFiles;
 388   SmallVector<BitcodeFile *, 0> lazyBitcodeFiles;
 389   // Duplicate symbol candidates.
 390   SmallVector<DuplicateSymbol, 0> duplicates;
 391   // Symbols in a non-prevailing COMDAT group which should be changed to an
 392   // Undefined.
 393   SmallVector<std::pair<Symbol *, unsigned>, 0> nonPrevailingSyms;
 394   // True if SHT_LLVM_SYMPART is used.
 395   std::atomic<bool> hasSympart{false};
 396   // A tuple of (reference, extractedFile, sym). Used by --why-extract=.
 397   SmallVector<std::tuple<std::string, const InputFile *, const Symbol &>, 0>
 398       whyExtractRecords;
 399   // A mapping from a symbol to an InputFile referencing it backward. Used by
 400   // --warn-backrefs.
 401   llvm::DenseMap<const Symbol *,
 402                  std::pair<const InputFile *, const InputFile *>>
 403       backwardReferences;
 404 };
 405
 406 // The only instance of Ctx struct.
 407 extern std::unique_ptr<Ctx> ctx;
 408
 409 // The first two elements of versionDefinitions represent VER_NDX_LOCAL and
 410 // VER_NDX_GLOBAL. This helper returns other elements.
 411 static inline ArrayRef<VersionDefinition> namedVersionDefs() {
 412   return llvm::makeArrayRef(config->versionDefinitions).slice(2);
 413 }
 414
 415 void errorOrWarn(const Twine &msg);
 416
 417 static inline void internalLinkerError(StringRef loc, const Twine &msg) {
 418   errorOrWarn(loc + "internal linker error: " + msg + "\n" +
 419               llvm::getBugReportMsg());
 420 }
 421
 422 } // namespace elf
 423 } // namespace lld
 424
 425 #endif