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 std::vector<VersionDefinition> versionDefinitions;
146 std::vector<llvm::StringRef> auxiliaryList;
147 std::vector<llvm::StringRef> filterList;
148 std::vector<llvm::StringRef> passPlugins;
149 std::vector<llvm::StringRef> searchPaths;
150 std::vector<llvm::StringRef> symbolOrderingFile;
151 std::vector<llvm::StringRef> thinLTOModulesToCompile;
152 std::vector<llvm::StringRef> undefined;
153 std::vector<SymbolVersion> dynamicList;
154 std::vector<uint8_t> 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 std::vector<std::pair<llvm::GlobPattern, uint64_t>> deadRelocInNonAlloc;
171 bool demangle = true;
172 bool dependentLibraries;
173 bool disableVerify;
174 bool ehFrameHdr;
175 bool emitLLVM;
176 bool emitRelocs;
177 bool enableNewDtags;
178 bool executeOnly;
179 bool exportDynamic;
180 bool fixCortexA53Errata843419;
181 bool fixCortexA8;
182 bool formatBinary = false;
183 bool fortranCommon;
184 bool gcSections;
185 bool gdbIndex;
186 bool gnuHash = false;
187 bool gnuUnique;
188 bool hasDynSymTab;
189 bool ignoreDataAddressEquality;
190 bool ignoreFunctionAddressEquality;
191 bool ltoCSProfileGenerate;
192 bool ltoPGOWarnMismatch;
193 bool ltoDebugPassManager;
194 bool ltoEmitAsm;
195 bool ltoUniqueBasicBlockSectionNames;
196 bool ltoWholeProgramVisibility;
197 bool mergeArmExidx;
198 bool mipsN32Abi = false;
199 bool mmapOutputFile;
200 bool nmagic;
201 bool noDynamicLinker = false;
202 bool noinhibitExec;
203 bool nostdlib;
204 bool oFormatBinary;
205 bool omagic;
206 bool opaquePointers;
207 bool optEB = false;
208 bool optEL = false;
209 bool optimizeBBJumps;
210 bool optRemarksWithHotness;
211 bool picThunk;
212 bool pie;
213 bool printGcSections;
214 bool printIcfSections;
215 bool relax;
216 bool relocatable;
217 bool relrGlibc = false;
218 bool relrPackDynRelocs = false;
219 llvm::DenseSet<llvm::StringRef> saveTempsArgs;
220 std::vector<std::pair<llvm::GlobPattern, uint32_t>> shuffleSections;
221 bool singleRoRx;
222 bool shared;
223 bool symbolic;
224 bool isStatic = false;
225 bool sysvHash = false;
226 bool target1Rel;
227 bool trace;
228 bool thinLTOEmitImportsFiles;
229 bool thinLTOEmitIndexFiles;
230 bool thinLTOIndexOnly;
231 bool timeTraceEnabled;
232 bool tocOptimize;
233 bool pcRelOptimize;
234 bool undefinedVersion;
235 bool unique;
236 bool useAndroidRelrTags = false;
237 bool warnBackrefs;
238 std::vector<llvm::GlobPattern> warnBackrefsExclude;
239 bool warnCommon;
240 bool warnMissingEntry;
241 bool warnSymbolOrdering;
242 bool writeAddends;
243 bool zCombreloc;
244 bool zCopyreloc;
245 bool zForceBti;
246 bool zForceIbt;
247 bool zGlobal;
248 bool zHazardplt;
249 bool zIfuncNoplt;
250 bool zInitfirst;
251 bool zInterpose;
252 bool zKeepTextSectionPrefix;
253 bool zNodefaultlib;
254 bool zNodelete;
255 bool zNodlopen;
256 bool zNow;
257 bool zOrigin;
258 bool zPacPlt;
259 bool zRelro;
260 bool zRodynamic;
261 bool zShstk;
262 bool zStartStopGC;
263 uint8_t zStartStopVisibility;
264 bool zText;
265 bool zRetpolineplt;
266 bool zWxneeded;
267 DiscardPolicy discard;
268 GnuStackKind zGnustack;
269 ICFLevel icf;
270 OrphanHandlingPolicy orphanHandling;
271 SortSectionPolicy sortSection;
272 StripPolicy strip;
273 UnresolvedPolicy unresolvedSymbols;
274 UnresolvedPolicy unresolvedSymbolsInShlib;
275 Target2Policy target2;
276 bool power10Stubs;
277 ARMVFPArgKind armVFPArgs = ARMVFPArgKind::Default;
278 BuildIdKind buildId = BuildIdKind::None;
279 SeparateSegmentKind zSeparate;
280 ELFKind ekind = ELFNoneKind;
281 uint16_t emachine = llvm::ELF::EM_NONE;
282 llvm::Optional<uint64_t> imageBase;
283 uint64_t commonPageSize;
284 uint64_t maxPageSize;
285 uint64_t mipsGotSize;
286 uint64_t zStackSize;
287 unsigned ltoPartitions;
288 unsigned ltoo;
289 unsigned optimize;
290 StringRef thinLTOJobs;
291 unsigned timeTraceGranularity;
292 int32_t splitStackAdjustSize;
293 StringRef packageMetadata;
294
295 // The following config options do not directly correspond to any
296 // particular command line options.
297
298 // True if we need to pass through relocations in input files to the
299 // output file. Usually false because we consume relocations.
300 bool copyRelocs;
301
302 // True if the target is ELF64. False if ELF32.
303 bool is64;
304
305 // True if the target is little-endian. False if big-endian.
306 bool isLE;
307
308 // endianness::little if isLE is true. endianness::big otherwise.
309 llvm::support::endianness endianness;
310
311 // True if the target is the little-endian MIPS64.
312 //
313 // The reason why we have this variable only for the MIPS is because
314 // we use this often. Some ELF headers for MIPS64EL are in a
315 // mixed-endian (which is horrible and I'd say that's a serious spec
316 // bug), and we need to know whether we are reading MIPS ELF files or
317 // not in various places.
318 //
319 // (Note that MIPS64EL is not a typo for MIPS64LE. This is the official
320 // name whatever that means. A fun hypothesis is that "EL" is short for
321 // little-endian written in the little-endian order, but I don't know
322 // if that's true.)
323 bool isMips64EL;
324
325 // True if we need to reserve two .got entries for local-dynamic TLS model.
326 bool needsTlsLd = false;
327
328 // True if we need to set the DF_STATIC_TLS flag to an output file, which
329 // works as a hint to the dynamic loader that the shared object contains code
330 // compiled with the initial-exec TLS model.
331 bool hasTlsIe = false;
332
333 // Holds set of ELF header flags for the target.
334 uint32_t eflags = 0;
335
336 // The ELF spec defines two types of relocation table entries, RELA and
337 // REL. RELA is a triplet of (offset, info, addend) while REL is a
338 // tuple of (offset, info). Addends for REL are implicit and read from
339 // the location where the relocations are applied. So, REL is more
340 // compact than RELA but requires a bit of more work to process.
341 //
342 // (From the linker writer's view, this distinction is not necessary.
343 // If the ELF had chosen whichever and sticked with it, it would have
344 // been easier to write code to process relocations, but it's too late
345 // to change the spec.)
346 //
347 // Each ABI defines its relocation type. IsRela is true if target
348 // uses RELA. As far as we know, all 64-bit ABIs are using RELA. A
349 // few 32-bit ABIs are using RELA too.
350 bool isRela;
351
352 // True if we are creating position-independent code.
353 bool isPic;
354
355 // 4 for ELF32, 8 for ELF64.
356 int wordsize;
357
358 // Mode of MTE to write to the ELF note. Should be one of NT_MEMTAG_ASYNC (for
359 // async), NT_MEMTAG_SYNC (for sync), or NT_MEMTAG_LEVEL_NONE (for none). If
360 // async or sync is enabled, write the ELF note specifying the default MTE
361 // mode.
362 int androidMemtagMode;
363 // Signal to the dynamic loader to enable heap MTE.
364 bool androidMemtagHeap;
365 // Signal to the dynamic loader that this binary expects stack MTE. Generally,
366 // this means to map the primary and thread stacks as PROT_MTE. Note: This is
367 // not supported on Android 11 & 12.
368 bool androidMemtagStack;
369 };
370
371 // The only instance of Configuration struct.
372 extern std::unique_ptr<Configuration> config;
373
374 struct DuplicateSymbol {
375 const Symbol *sym;
376 const InputFile *file;
377 InputSectionBase *section;
378 uint64_t value;
379 };
380
381 struct Ctx {
382 SmallVector<std::unique_ptr<MemoryBuffer>> memoryBuffers;
383 SmallVector<ELFFileBase *, 0> objectFiles;
384 SmallVector<SharedFile *, 0> sharedFiles;
385 SmallVector<BinaryFile *, 0> binaryFiles;
386 SmallVector<BitcodeFile *, 0> bitcodeFiles;
387 SmallVector<BitcodeFile *, 0> lazyBitcodeFiles;
388 // Duplicate symbol candidates.
389 SmallVector<DuplicateSymbol, 0> duplicates;
390 // Symbols in a non-prevailing COMDAT group which should be changed to an
391 // Undefined.
392 SmallVector<std::pair<Symbol *, unsigned>, 0> nonPrevailingSyms;
393 // True if SHT_LLVM_SYMPART is used.
394 std::atomic<bool> hasSympart{false};
395 // A tuple of (reference, extractedFile, sym). Used by --why-extract=.
396 SmallVector<std::tuple<std::string, const InputFile *, const Symbol &>, 0>
397 whyExtractRecords;
398 // A mapping from a symbol to an InputFile referencing it backward. Used by
399 // --warn-backrefs.
400 llvm::DenseMap<const Symbol *,
401 std::pair<const InputFile *, const InputFile *>>
402 backwardReferences;
403 };
404
405 // The only instance of Ctx struct.
406 extern std::unique_ptr<Ctx> ctx;
407
408 // The first two elements of versionDefinitions represent VER_NDX_LOCAL and
409 // VER_NDX_GLOBAL. This helper returns other elements.
namedVersionDefs()410 static inline ArrayRef<VersionDefinition> namedVersionDefs() {
411 return llvm::makeArrayRef(config->versionDefinitions).slice(2);
412 }
413
414 void errorOrWarn(const Twine &msg);
415
internalLinkerError(StringRef loc,const Twine & msg)416 static inline void internalLinkerError(StringRef loc, const Twine &msg) {
417 errorOrWarn(loc + "internal linker error: " + msg + "\n" +
418 llvm::getBugReportMsg());
419 }
420
421 } // namespace elf
422 } // namespace lld
423
424 #endif
425