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/SmallSet.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/ADT/StringSet.h"
20#include "llvm/BinaryFormat/ELF.h"
21#include "llvm/Option/ArgList.h"
22#include "llvm/Support/CachePruning.h"
23#include "llvm/Support/CodeGen.h"
24#include "llvm/Support/Compiler.h"
25#include "llvm/Support/Compression.h"
26#include "llvm/Support/Endian.h"
27#include "llvm/Support/FileSystem.h"
28#include "llvm/Support/GlobPattern.h"
29#include "llvm/Support/PrettyStackTrace.h"
30#include <atomic>
31#include <memory>
32#include <optional>
33#include <vector>
34
35namespace lld::elf {
36
37class InputFile;
38class BinaryFile;
39class BitcodeFile;
40class ELFFileBase;
41class SharedFile;
42class InputSectionBase;
43class EhInputSection;
44class Symbol;
45class BitcodeCompiler;
46
47enum ELFKind : uint8_t {
48 ELFNoneKind,
49 ELF32LEKind,
50 ELF32BEKind,
51 ELF64LEKind,
52 ELF64BEKind
53};
54
55// For -Bno-symbolic, -Bsymbolic-non-weak-functions, -Bsymbolic-functions,
56// -Bsymbolic-non-weak, -Bsymbolic.
57enum class BsymbolicKind { None, NonWeakFunctions, Functions, NonWeak, All };
58
59// For --build-id.
60enum class BuildIdKind { None, Fast, Md5, Sha1, Hexstring, Uuid };
61
62// For --call-graph-profile-sort={none,hfsort,cdsort}.
63enum class CGProfileSortKind { None, Hfsort, Cdsort };
64
65// For --discard-{all,locals,none}.
66enum class DiscardPolicy { Default, All, Locals, None };
67
68// For --icf={none,safe,all}.
69enum class ICFLevel { None, Safe, All };
70
71// For --strip-{all,debug}.
72enum class StripPolicy { None, All, Debug };
73
74// For --unresolved-symbols.
75enum class UnresolvedPolicy { ReportError, Warn, Ignore };
76
77// For --orphan-handling.
78enum class OrphanHandlingPolicy { Place, Warn, Error };
79
80// For --sort-section and linkerscript sorting rules.
81enum class SortSectionPolicy {
82 Default,
83 None,
84 Alignment,
85 Name,
86 Priority,
87 Reverse,
88};
89
90// For --target2
91enum class Target2Policy { Abs, Rel, GotRel };
92
93// For tracking ARM Float Argument PCS
94enum class ARMVFPArgKind { Default, Base, VFP, ToolChain };
95
96// For -z noseparate-code, -z separate-code and -z separate-loadable-segments.
97enum class SeparateSegmentKind { None, Code, Loadable };
98
99// For -z *stack
100enum class GnuStackKind { None, Exec, NoExec };
101
102// For --lto=
103enum LtoKind : uint8_t {UnifiedThin, UnifiedRegular, Default};
104
105struct SymbolVersion {
106 llvm::StringRef name;
107 bool isExternCpp;
108 bool hasWildcard;
109};
110
111// This struct contains symbols version definition that
112// can be found in version script if it is used for link.
113struct VersionDefinition {
114 llvm::StringRef name;
115 uint16_t id;
116 SmallVector<SymbolVersion, 0> nonLocalPatterns;
117 SmallVector<SymbolVersion, 0> localPatterns;
118};
119
120class LinkerDriver {
121public:
122 void linkerMain(ArrayRef<const char *> args);
123 void addFile(StringRef path, bool withLOption);
124 void addLibrary(StringRef name);
125
126private:
127 void createFiles(llvm::opt::InputArgList &args);
128 void inferMachineType();
129 template <class ELFT> void link(llvm::opt::InputArgList &args);
130 template <class ELFT> void compileBitcodeFiles(bool skipLinkedOutput);
131 bool tryAddFatLTOFile(MemoryBufferRef mb, StringRef archiveName,
132 uint64_t offsetInArchive, bool lazy);
133 // True if we are in --whole-archive and --no-whole-archive.
134 bool inWholeArchive = false;
135
136 // True if we are in --start-lib and --end-lib.
137 bool inLib = false;
138
139 std::unique_ptr<BitcodeCompiler> lto;
140 std::vector<InputFile *> files;
141 InputFile *armCmseImpLib = nullptr;
142
143public:
144 SmallVector<std::pair<StringRef, unsigned>, 0> archiveFiles;
145};
146
147// This struct contains the global configuration for the linker.
148// Most fields are direct mapping from the command line options
149// and such fields have the same name as the corresponding options.
150// Most fields are initialized by the ctx.driver.
151struct Config {
152 uint8_t osabi = 0;
153 uint32_t andFeatures = 0;
154 llvm::CachePruningPolicy thinLTOCachePolicy;
155 llvm::SetVector<llvm::CachedHashString> dependencyFiles; // for --dependency-file
156 llvm::StringMap<uint64_t> sectionStartMap;
157 llvm::StringRef bfdname;
158 llvm::StringRef chroot;
159 llvm::StringRef dependencyFile;
160 llvm::StringRef dwoDir;
161 llvm::StringRef dynamicLinker;
162 llvm::StringRef entry;
163 llvm::StringRef emulation;
164 llvm::StringRef fini;
165 llvm::StringRef init;
166 llvm::StringRef ltoAAPipeline;
167 llvm::StringRef ltoCSProfileFile;
168 llvm::StringRef ltoNewPmPasses;
169 llvm::StringRef ltoObjPath;
170 llvm::StringRef ltoSampleProfile;
171 llvm::StringRef mapFile;
172 llvm::StringRef outputFile;
173 llvm::StringRef optRemarksFilename;
174 std::optional<uint64_t> optRemarksHotnessThreshold = 0;
175 llvm::StringRef optRemarksPasses;
176 llvm::StringRef optRemarksFormat;
177 llvm::StringRef optStatsFilename;
178 llvm::StringRef progName;
179 llvm::StringRef printArchiveStats;
180 llvm::StringRef printSymbolOrder;
181 llvm::StringRef soName;
182 llvm::StringRef sysroot;
183 llvm::StringRef thinLTOCacheDir;
184 llvm::StringRef thinLTOIndexOnlyArg;
185 llvm::StringRef whyExtract;
186 llvm::StringRef cmseInputLib;
187 llvm::StringRef cmseOutputLib;
188 StringRef zBtiReport = "none";
189 StringRef zCetReport = "none";
190 StringRef zPauthReport = "none";
191 bool ltoBBAddrMap;
192 llvm::StringRef ltoBasicBlockSections;
193 std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace;
194 llvm::StringRef thinLTOPrefixReplaceOld;
195 llvm::StringRef thinLTOPrefixReplaceNew;
196 llvm::StringRef thinLTOPrefixReplaceNativeObject;
197 std::string rpath;
198 llvm::SmallVector<VersionDefinition, 0> versionDefinitions;
199 llvm::SmallVector<llvm::StringRef, 0> auxiliaryList;
200 llvm::SmallVector<llvm::StringRef, 0> filterList;
201 llvm::SmallVector<llvm::StringRef, 0> passPlugins;
202 llvm::SmallVector<llvm::StringRef, 0> searchPaths;
203 llvm::SmallVector<llvm::StringRef, 0> symbolOrderingFile;
204 llvm::SmallVector<llvm::StringRef, 0> thinLTOModulesToCompile;
205 llvm::SmallVector<llvm::StringRef, 0> undefined;
206 llvm::SmallVector<SymbolVersion, 0> dynamicList;
207 llvm::SmallVector<uint8_t, 0> buildIdVector;
208 llvm::SmallVector<llvm::StringRef, 0> mllvmOpts;
209 llvm::MapVector<std::pair<const InputSectionBase *, const InputSectionBase *>,
210 uint64_t>
211 callGraphProfile;
212 bool cmseImplib = false;
213 bool allowMultipleDefinition;
214 bool fatLTOObjects;
215 bool androidPackDynRelocs = false;
216 bool armHasBlx = false;
217 bool armHasMovtMovw = false;
218 bool armJ1J2BranchEncoding = false;
219 bool armCMSESupport = false;
220 bool asNeeded = false;
221 bool armBe8 = false;
222 BsymbolicKind bsymbolic = BsymbolicKind::None;
223 CGProfileSortKind callGraphProfileSort;
224 bool checkSections;
225 bool checkDynamicRelocs;
226 std::optional<llvm::DebugCompressionType> compressDebugSections;
227 llvm::SmallVector<std::pair<llvm::GlobPattern, llvm::DebugCompressionType>, 0>
228 compressSections;
229 bool cref;
230 llvm::SmallVector<std::pair<llvm::GlobPattern, uint64_t>, 0>
231 deadRelocInNonAlloc;
232 bool debugNames;
233 bool demangle = true;
234 bool dependentLibraries;
235 bool disableVerify;
236 bool ehFrameHdr;
237 bool emitLLVM;
238 bool emitRelocs;
239 bool enableNewDtags;
240 bool executeOnly;
241 bool exportDynamic;
242 bool fixCortexA53Errata843419;
243 bool fixCortexA8;
244 bool formatBinary = false;
245 bool fortranCommon;
246 bool gcSections;
247 bool gdbIndex;
248 bool gnuHash = false;
249 bool gnuUnique;
250 bool hasDynSymTab;
251 bool ignoreDataAddressEquality;
252 bool ignoreFunctionAddressEquality;
253 bool ltoCSProfileGenerate;
254 bool ltoPGOWarnMismatch;
255 bool ltoDebugPassManager;
256 bool ltoEmitAsm;
257 bool ltoUniqueBasicBlockSectionNames;
258 bool ltoValidateAllVtablesHaveTypeInfos;
259 bool ltoWholeProgramVisibility;
260 bool mergeArmExidx;
261 bool mipsN32Abi = false;
262 bool mmapOutputFile;
263 bool nmagic;
264 bool noDynamicLinker = false;
265 bool noinhibitExec;
266 bool nostdlib;
267 bool oFormatBinary;
268 bool omagic;
269 bool optEB = false;
270 bool optEL = false;
271 bool optimizeBBJumps;
272 bool optRemarksWithHotness;
273 bool picThunk;
274 bool pie;
275 bool printGcSections;
276 bool printIcfSections;
277 bool printMemoryUsage;
278 bool rejectMismatch;
279 bool relax;
280 bool relaxGP;
281 bool relocatable;
282 bool relrGlibc = false;
283 bool relrPackDynRelocs = false;
284 llvm::DenseSet<llvm::StringRef> saveTempsArgs;
285 llvm::SmallVector<std::pair<llvm::GlobPattern, uint32_t>, 0> shuffleSections;
286 bool singleRoRx;
287 bool shared;
288 bool symbolic;
289 bool isStatic = false;
290 bool sysvHash = false;
291 bool target1Rel;
292 bool trace;
293 bool thinLTOEmitImportsFiles;
294 bool thinLTOEmitIndexFiles;
295 bool thinLTOIndexOnly;
296 bool timeTraceEnabled;
297 bool tocOptimize;
298 bool pcRelOptimize;
299 bool undefinedVersion;
300 bool unique;
301 bool useAndroidRelrTags = false;
302 bool warnBackrefs;
303 llvm::SmallVector<llvm::GlobPattern, 0> warnBackrefsExclude;
304 bool warnCommon;
305 bool warnMissingEntry;
306 bool warnSymbolOrdering;
307 bool writeAddends;
308 bool zCombreloc;
309 bool zCopyreloc;
310 bool zForceBti;
311 bool zForceIbt;
312 bool zGlobal;
313 bool zHazardplt;
314 bool zIfuncNoplt;
315 bool zInitfirst;
316 bool zInterpose;
317 bool zKeepTextSectionPrefix;
318 bool zLrodataAfterBss;
319 bool zNodefaultlib;
320 bool zNodelete;
321 bool zNodlopen;
322 bool zNow;
323 bool zOrigin;
324 bool zPacPlt;
325 bool zRelro;
326 bool zRodynamic;
327 bool zShstk;
328 bool zStartStopGC;
329 uint8_t zStartStopVisibility;
330 bool zText;
331 bool zRetpolineplt;
332 bool zWxneeded;
333 DiscardPolicy discard;
334 GnuStackKind zGnustack;
335 ICFLevel icf;
336 OrphanHandlingPolicy orphanHandling;
337 SortSectionPolicy sortSection;
338 StripPolicy strip;
339 UnresolvedPolicy unresolvedSymbols;
340 UnresolvedPolicy unresolvedSymbolsInShlib;
341 Target2Policy target2;
342 bool power10Stubs;
343 ARMVFPArgKind armVFPArgs = ARMVFPArgKind::Default;
344 BuildIdKind buildId = BuildIdKind::None;
345 SeparateSegmentKind zSeparate;
346 ELFKind ekind = ELFNoneKind;
347 uint16_t emachine = llvm::ELF::EM_NONE;
348 std::optional<uint64_t> imageBase;
349 uint64_t commonPageSize;
350 uint64_t maxPageSize;
351 uint64_t mipsGotSize;
352 uint64_t zStackSize;
353 unsigned ltoPartitions;
354 unsigned ltoo;
355 llvm::CodeGenOptLevel ltoCgo;
356 unsigned optimize;
357 StringRef thinLTOJobs;
358 unsigned timeTraceGranularity;
359 int32_t splitStackAdjustSize;
360 StringRef packageMetadata;
361
362 // The following config options do not directly correspond to any
363 // particular command line options.
364
365 // True if we need to pass through relocations in input files to the
366 // output file. Usually false because we consume relocations.
367 bool copyRelocs;
368
369 // True if the target is ELF64. False if ELF32.
370 bool is64;
371
372 // True if the target is little-endian. False if big-endian.
373 bool isLE;
374
375 // endianness::little if isLE is true. endianness::big otherwise.
376 llvm::endianness endianness;
377
378 // True if the target is the little-endian MIPS64.
379 //
380 // The reason why we have this variable only for the MIPS is because
381 // we use this often. Some ELF headers for MIPS64EL are in a
382 // mixed-endian (which is horrible and I'd say that's a serious spec
383 // bug), and we need to know whether we are reading MIPS ELF files or
384 // not in various places.
385 //
386 // (Note that MIPS64EL is not a typo for MIPS64LE. This is the official
387 // name whatever that means. A fun hypothesis is that "EL" is short for
388 // little-endian written in the little-endian order, but I don't know
389 // if that's true.)
390 bool isMips64EL;
391
392 // True if we need to set the DF_STATIC_TLS flag to an output file, which
393 // works as a hint to the dynamic loader that the shared object contains code
394 // compiled with the initial-exec TLS model.
395 bool hasTlsIe = false;
396
397 // Holds set of ELF header flags for the target.
398 uint32_t eflags = 0;
399
400 // The ELF spec defines two types of relocation table entries, RELA and
401 // REL. RELA is a triplet of (offset, info, addend) while REL is a
402 // tuple of (offset, info). Addends for REL are implicit and read from
403 // the location where the relocations are applied. So, REL is more
404 // compact than RELA but requires a bit of more work to process.
405 //
406 // (From the linker writer's view, this distinction is not necessary.
407 // If the ELF had chosen whichever and sticked with it, it would have
408 // been easier to write code to process relocations, but it's too late
409 // to change the spec.)
410 //
411 // Each ABI defines its relocation type. IsRela is true if target
412 // uses RELA. As far as we know, all 64-bit ABIs are using RELA. A
413 // few 32-bit ABIs are using RELA too.
414 bool isRela;
415
416 // True if we are creating position-independent code.
417 bool isPic;
418
419 // 4 for ELF32, 8 for ELF64.
420 int wordsize;
421
422 // Mode of MTE to write to the ELF note. Should be one of NT_MEMTAG_ASYNC (for
423 // async), NT_MEMTAG_SYNC (for sync), or NT_MEMTAG_LEVEL_NONE (for none). If
424 // async or sync is enabled, write the ELF note specifying the default MTE
425 // mode.
426 int androidMemtagMode;
427 // Signal to the dynamic loader to enable heap MTE.
428 bool androidMemtagHeap;
429 // Signal to the dynamic loader that this binary expects stack MTE. Generally,
430 // this means to map the primary and thread stacks as PROT_MTE. Note: This is
431 // not supported on Android 11 & 12.
432 bool androidMemtagStack;
433
434 // When using a unified pre-link LTO pipeline, specify the backend LTO mode.
435 LtoKind ltoKind = LtoKind::Default;
436
437 unsigned threadCount;
438
439 // If an input file equals a key, remap it to the value.
440 llvm::DenseMap<llvm::StringRef, llvm::StringRef> remapInputs;
441 // If an input file matches a wildcard pattern, remap it to the value.
442 llvm::SmallVector<std::pair<llvm::GlobPattern, llvm::StringRef>, 0>
443 remapInputsWildcards;
444};
445struct ConfigWrapper {
446 Config c;
447 Config *operator->() { return &c; }
448};
449
450LLVM_LIBRARY_VISIBILITY extern ConfigWrapper config;
451
452struct DuplicateSymbol {
453 const Symbol *sym;
454 const InputFile *file;
455 InputSectionBase *section;
456 uint64_t value;
457};
458
459struct Ctx {
460 LinkerDriver driver;
461 SmallVector<std::unique_ptr<MemoryBuffer>> memoryBuffers;
462 SmallVector<ELFFileBase *, 0> objectFiles;
463 SmallVector<SharedFile *, 0> sharedFiles;
464 SmallVector<BinaryFile *, 0> binaryFiles;
465 SmallVector<BitcodeFile *, 0> bitcodeFiles;
466 SmallVector<BitcodeFile *, 0> lazyBitcodeFiles;
467 SmallVector<InputSectionBase *, 0> inputSections;
468 SmallVector<EhInputSection *, 0> ehInputSections;
469 // Duplicate symbol candidates.
470 SmallVector<DuplicateSymbol, 0> duplicates;
471 // Symbols in a non-prevailing COMDAT group which should be changed to an
472 // Undefined.
473 SmallVector<std::pair<Symbol *, unsigned>, 0> nonPrevailingSyms;
474 // A tuple of (reference, extractedFile, sym). Used by --why-extract=.
475 SmallVector<std::tuple<std::string, const InputFile *, const Symbol &>, 0>
476 whyExtractRecords;
477 // A mapping from a symbol to an InputFile referencing it backward. Used by
478 // --warn-backrefs.
479 llvm::DenseMap<const Symbol *,
480 std::pair<const InputFile *, const InputFile *>>
481 backwardReferences;
482 llvm::SmallSet<llvm::StringRef, 0> auxiliaryFiles;
483 // InputFile for linker created symbols with no source location.
484 InputFile *internalFile;
485 // True if SHT_LLVM_SYMPART is used.
486 std::atomic<bool> hasSympart{false};
487 // True if there are TLS IE relocations. Set DF_STATIC_TLS if -shared.
488 std::atomic<bool> hasTlsIe{false};
489 // True if we need to reserve two .got entries for local-dynamic TLS model.
490 std::atomic<bool> needsTlsLd{false};
491 // True if all native vtable symbols have corresponding type info symbols
492 // during LTO.
493 bool ltoAllVtablesHaveTypeInfos;
494
495 // Each symbol assignment and DEFINED(sym) reference is assigned an increasing
496 // order. Each DEFINED(sym) evaluation checks whether the reference happens
497 // before a possible `sym = expr;`.
498 unsigned scriptSymOrderCounter = 1;
499 llvm::DenseMap<const Symbol *, unsigned> scriptSymOrder;
500
501 void reset();
502
503 llvm::raw_fd_ostream openAuxiliaryFile(llvm::StringRef, std::error_code &);
504
505 ArrayRef<uint8_t> aarch64PauthAbiCoreInfo;
506};
507
508LLVM_LIBRARY_VISIBILITY extern Ctx ctx;
509
510// The first two elements of versionDefinitions represent VER_NDX_LOCAL and
511// VER_NDX_GLOBAL. This helper returns other elements.
512static inline ArrayRef<VersionDefinition> namedVersionDefs() {
513 return llvm::ArrayRef(config->versionDefinitions).slice(N: 2);
514}
515
516void errorOrWarn(const Twine &msg);
517
518static inline void internalLinkerError(StringRef loc, const Twine &msg) {
519 errorOrWarn(msg: loc + "internal linker error: " + msg + "\n" +
520 llvm::getBugReportMsg());
521}
522
523} // namespace lld::elf
524
525#endif
526

source code of lld/ELF/Config.h