1 //===- SymbolTable.cpp ----------------------------------------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Symbol table is a bag of all known symbols. We put all symbols of
11 // all input files to the symbol table. The symbol table is basically
12 // a hash table with the logic to resolve symbol name conflicts using
15 //===----------------------------------------------------------------------===//
17 #include "SymbolTable.h"
20 #include "LinkerScript.h"
23 #include "llvm/ADT/STLExtras.h"
26 using namespace llvm::object;
27 using namespace llvm::ELF;
30 using namespace lld::elf;
32 // All input object files must be for the same architecture
33 // (e.g. it does not make sense to link x86 object files with
34 // MIPS object files.) This function checks for that error.
35 template <class ELFT> static bool isCompatible(InputFile *F) {
36 if (!isa<ELFFileBase<ELFT>>(F) && !isa<BitcodeFile>(F))
39 if (F->EKind == Config->EKind && F->EMachine == Config->EMachine) {
40 if (Config->EMachine != EM_MIPS)
42 if (isMipsN32Abi(F) == Config->MipsN32Abi)
46 if (!Config->Emulation.empty())
47 error(toString(F) + " is incompatible with " + Config->Emulation);
49 error(toString(F) + " is incompatible with " + toString(Config->FirstElf));
53 // Add symbols in File to the symbol table.
54 template <class ELFT> void SymbolTable<ELFT>::addFile(InputFile *File) {
55 if (!Config->FirstElf && isa<ELFFileBase<ELFT>>(File))
56 Config->FirstElf = File;
58 if (!isCompatible<ELFT>(File))
62 if (auto *F = dyn_cast<BinaryFile>(File)) {
63 BinaryFiles.push_back(F);
69 if (auto *F = dyn_cast<ArchiveFile>(File)) {
75 if (auto *F = dyn_cast<LazyObjectFile>(File)) {
81 message(toString(File));
84 if (auto *F = dyn_cast<SharedFile<ELFT>>(File)) {
85 // DSOs are uniquified not by filename but by soname.
87 if (ErrorCount || !SoNames.insert(F->SoName).second)
89 SharedFiles.push_back(F);
95 if (auto *F = dyn_cast<BitcodeFile>(File)) {
96 BitcodeFiles.push_back(F);
97 F->parse<ELFT>(ComdatGroups);
101 // Regular object file
102 auto *F = cast<ObjectFile<ELFT>>(File);
103 ObjectFiles.push_back(F);
104 F->parse(ComdatGroups);
107 // This function is where all the optimizations of link-time
108 // optimization happens. When LTO is in use, some input files are
109 // not in native object file format but in the LLVM bitcode format.
110 // This function compiles bitcode files into a few big native files
111 // using LLVM functions and replaces bitcode symbols with the results.
112 // Because all bitcode files that consist of a program are passed
113 // to the compiler at once, it can do whole-program optimization.
114 template <class ELFT> void SymbolTable<ELFT>::addCombinedLTOObject() {
115 if (BitcodeFiles.empty())
118 // Compile bitcode files and replace bitcode symbols.
119 LTO.reset(new BitcodeCompiler);
120 for (BitcodeFile *F : BitcodeFiles)
123 for (InputFile *File : LTO->compile()) {
124 ObjectFile<ELFT> *Obj = cast<ObjectFile<ELFT>>(File);
125 DenseSet<CachedHashStringRef> DummyGroups;
126 Obj->parse(DummyGroups);
127 ObjectFiles.push_back(Obj);
131 template <class ELFT>
132 DefinedRegular *SymbolTable<ELFT>::addAbsolute(StringRef Name,
136 addRegular(Name, Visibility, STT_NOTYPE, 0, 0, Binding, nullptr, nullptr);
137 return cast<DefinedRegular>(Sym->body());
140 // Add Name as an "ignored" symbol. An ignored symbol is a regular
141 // linker-synthesized defined symbol, but is only defined if needed.
142 template <class ELFT>
143 DefinedRegular *SymbolTable<ELFT>::addIgnored(StringRef Name,
144 uint8_t Visibility) {
145 SymbolBody *S = find(Name);
146 if (!S || S->isInCurrentDSO())
148 return addAbsolute(Name, Visibility);
151 // Set a flag for --trace-symbol so that we can print out a log message
152 // if a new symbol with the same name is inserted into the symbol table.
153 template <class ELFT> void SymbolTable<ELFT>::trace(StringRef Name) {
154 Symtab.insert({CachedHashStringRef(Name), {-1, true}});
157 // Rename SYM as __wrap_SYM. The original symbol is preserved as __real_SYM.
158 // Used to implement --wrap.
159 template <class ELFT> void SymbolTable<ELFT>::addSymbolWrap(StringRef Name) {
160 SymbolBody *B = find(Name);
163 Symbol *Sym = B->symbol();
164 Symbol *Real = addUndefined(Saver.save("__real_" + Name));
165 Symbol *Wrap = addUndefined(Saver.save("__wrap_" + Name));
167 // Tell LTO not to eliminate this symbol
168 Wrap->IsUsedInRegularObj = true;
170 Config->RenamedSymbols[Real] = {Sym, Real->Binding};
171 Config->RenamedSymbols[Sym] = {Wrap, Sym->Binding};
174 // Creates alias for symbol. Used to implement --defsym=ALIAS=SYM.
175 template <class ELFT> void SymbolTable<ELFT>::addSymbolAlias(StringRef Alias,
177 SymbolBody *B = find(Name);
179 error("-defsym: undefined symbol: " + Name);
182 Symbol *Sym = B->symbol();
183 Symbol *AliasSym = addUndefined(Alias);
185 // Tell LTO not to eliminate this symbol
186 Sym->IsUsedInRegularObj = true;
187 Config->RenamedSymbols[AliasSym] = {Sym, AliasSym->Binding};
190 // Apply symbol renames created by -wrap and -defsym. The renames are created
191 // before LTO in addSymbolWrap() and addSymbolAlias() to have a chance to inform
192 // LTO (if LTO is running) not to include these symbols in IPO. Now that the
193 // symbols are finalized, we can perform the replacement.
194 template <class ELFT> void SymbolTable<ELFT>::applySymbolRenames() {
195 for (auto &KV : Config->RenamedSymbols) {
196 Symbol *Dst = KV.first;
197 Symbol *Src = KV.second.Target;
198 Dst->body()->copy(Src->body());
199 Dst->Binding = KV.second.OriginalBinding;
203 static uint8_t getMinVisibility(uint8_t VA, uint8_t VB) {
204 if (VA == STV_DEFAULT)
206 if (VB == STV_DEFAULT)
208 return std::min(VA, VB);
211 // Find an existing symbol or create and insert a new one.
212 template <class ELFT>
213 std::pair<Symbol *, bool> SymbolTable<ELFT>::insert(StringRef Name) {
214 auto P = Symtab.insert(
215 {CachedHashStringRef(Name), SymIndex((int)SymVector.size(), false)});
216 SymIndex &V = P.first->second;
217 bool IsNew = P.second;
221 V = SymIndex((int)SymVector.size(), true);
226 Sym = make<Symbol>();
227 Sym->InVersionScript = false;
228 Sym->Binding = STB_WEAK;
229 Sym->Visibility = STV_DEFAULT;
230 Sym->IsUsedInRegularObj = false;
231 Sym->ExportDynamic = false;
232 Sym->Traced = V.Traced;
233 Sym->VersionId = Config->DefaultSymbolVersion;
234 SymVector.push_back(Sym);
236 Sym = SymVector[V.Idx];
241 // Find an existing symbol or create and insert a new one, then apply the given
243 template <class ELFT>
244 std::pair<Symbol *, bool>
245 SymbolTable<ELFT>::insert(StringRef Name, uint8_t Type, uint8_t Visibility,
246 bool CanOmitFromDynSym, InputFile *File) {
247 bool IsUsedInRegularObj = !File || File->kind() == InputFile::ObjectKind;
250 std::tie(S, WasInserted) = insert(Name);
252 // Merge in the new symbol's visibility.
253 S->Visibility = getMinVisibility(S->Visibility, Visibility);
255 if (!CanOmitFromDynSym && (Config->Shared || Config->ExportDynamic))
256 S->ExportDynamic = true;
258 if (IsUsedInRegularObj)
259 S->IsUsedInRegularObj = true;
261 if (!WasInserted && S->body()->Type != SymbolBody::UnknownType &&
262 ((Type == STT_TLS) != S->body()->isTls())) {
263 error("TLS attribute mismatch: " + toString(*S->body()) +
264 "\n>>> defined in " + toString(S->body()->File) +
265 "\n>>> defined in " + toString(File));
268 return {S, WasInserted};
271 template <class ELFT> Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name) {
272 return addUndefined(Name, /*IsLocal=*/false, STB_GLOBAL, STV_DEFAULT,
274 /*CanOmitFromDynSym*/ false, /*File*/ nullptr);
277 static uint8_t getVisibility(uint8_t StOther) { return StOther & 3; }
279 template <class ELFT>
280 Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name, bool IsLocal,
281 uint8_t Binding, uint8_t StOther,
282 uint8_t Type, bool CanOmitFromDynSym,
286 uint8_t Visibility = getVisibility(StOther);
287 std::tie(S, WasInserted) =
288 insert(Name, Type, Visibility, CanOmitFromDynSym, File);
289 // An undefined symbol with non default visibility must be satisfied
292 (isa<SharedSymbol>(S->body()) && Visibility != STV_DEFAULT)) {
293 S->Binding = Binding;
294 replaceBody<Undefined>(S, Name, IsLocal, StOther, Type, File);
297 if (Binding != STB_WEAK) {
298 SymbolBody *B = S->body();
299 if (B->isShared() || B->isLazy() || B->isUndefined())
300 S->Binding = Binding;
301 if (auto *SS = dyn_cast<SharedSymbol>(B))
302 cast<SharedFile<ELFT>>(SS->File)->IsUsed = true;
304 if (auto *L = dyn_cast<Lazy>(S->body())) {
305 // An undefined weak will not fetch archive members, but we have to remember
306 // its type. See also comment in addLazyArchive.
309 else if (InputFile *F = L->fetch())
315 // We have a new defined symbol with the specified binding. Return 1 if the new
316 // symbol should win, -1 if the new symbol should lose, or 0 if both symbols are
317 // strong defined symbols.
318 static int compareDefined(Symbol *S, bool WasInserted, uint8_t Binding) {
321 SymbolBody *Body = S->body();
322 if (Body->isLazy() || !Body->isInCurrentDSO())
324 if (Binding == STB_WEAK)
331 // We have a new non-common defined symbol with the specified binding. Return 1
332 // if the new symbol should win, -1 if the new symbol should lose, or 0 if there
333 // is a conflict. If the new symbol wins, also update the binding.
334 template <typename ELFT>
335 static int compareDefinedNonCommon(Symbol *S, bool WasInserted, uint8_t Binding,
336 bool IsAbsolute, typename ELFT::uint Value) {
337 if (int Cmp = compareDefined(S, WasInserted, Binding)) {
339 S->Binding = Binding;
342 SymbolBody *B = S->body();
343 if (isa<DefinedCommon>(B)) {
344 // Non-common symbols take precedence over common symbols.
345 if (Config->WarnCommon)
346 warn("common " + S->body()->getName() + " is overridden");
348 } else if (auto *R = dyn_cast<DefinedRegular>(B)) {
349 if (R->Section == nullptr && Binding == STB_GLOBAL && IsAbsolute &&
356 template <class ELFT>
357 Symbol *SymbolTable<ELFT>::addCommon(StringRef N, uint64_t Size,
358 uint32_t Alignment, uint8_t Binding,
359 uint8_t StOther, uint8_t Type,
363 std::tie(S, WasInserted) = insert(N, Type, getVisibility(StOther),
364 /*CanOmitFromDynSym*/ false, File);
365 int Cmp = compareDefined(S, WasInserted, Binding);
367 S->Binding = Binding;
368 replaceBody<DefinedCommon>(S, N, Size, Alignment, StOther, Type, File);
369 } else if (Cmp == 0) {
370 auto *C = dyn_cast<DefinedCommon>(S->body());
372 // Non-common symbols take precedence over common symbols.
373 if (Config->WarnCommon)
374 warn("common " + S->body()->getName() + " is overridden");
378 if (Config->WarnCommon)
379 warn("multiple common of " + S->body()->getName());
381 Alignment = C->Alignment = std::max(C->Alignment, Alignment);
383 replaceBody<DefinedCommon>(S, N, Size, Alignment, StOther, Type, File);
388 static void warnOrError(const Twine &Msg) {
389 if (Config->AllowMultipleDefinition)
395 static void reportDuplicate(SymbolBody *Sym, InputFile *NewFile) {
396 warnOrError("duplicate symbol: " + toString(*Sym) +
397 "\n>>> defined in " + toString(Sym->File) +
398 "\n>>> defined in " + toString(NewFile));
401 template <class ELFT>
402 static void reportDuplicate(SymbolBody *Sym, InputSectionBase *ErrSec,
403 typename ELFT::uint ErrOffset) {
404 DefinedRegular *D = dyn_cast<DefinedRegular>(Sym);
405 if (!D || !D->Section || !ErrSec) {
406 reportDuplicate(Sym, ErrSec ? ErrSec->getFile<ELFT>() : nullptr);
410 // Construct and print an error message in the form of:
412 // ld.lld: error: duplicate symbol: foo
413 // >>> defined at bar.c:30
414 // >>> bar.o (/home/alice/src/bar.o)
415 // >>> defined at baz.c:563
416 // >>> baz.o in archive libbaz.a
417 auto *Sec1 = cast<InputSectionBase>(D->Section);
418 std::string Src1 = Sec1->getSrcMsg<ELFT>(D->Value);
419 std::string Obj1 = Sec1->getObjMsg<ELFT>(D->Value);
420 std::string Src2 = ErrSec->getSrcMsg<ELFT>(ErrOffset);
421 std::string Obj2 = ErrSec->getObjMsg<ELFT>(ErrOffset);
423 std::string Msg = "duplicate symbol: " + toString(*Sym) + "\n>>> defined at ";
425 Msg += Src1 + "\n>>> ";
426 Msg += Obj1 + "\n>>> defined at ";
428 Msg += Src2 + "\n>>> ";
433 template <typename ELFT>
434 Symbol *SymbolTable<ELFT>::addRegular(StringRef Name, uint8_t StOther,
435 uint8_t Type, uint64_t Value,
436 uint64_t Size, uint8_t Binding,
437 SectionBase *Section, InputFile *File) {
440 std::tie(S, WasInserted) = insert(Name, Type, getVisibility(StOther),
441 /*CanOmitFromDynSym*/ false, File);
442 int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Binding,
443 Section == nullptr, Value);
445 replaceBody<DefinedRegular>(S, Name, /*IsLocal=*/false, StOther, Type,
446 Value, Size, Section, File);
448 reportDuplicate<ELFT>(S->body(),
449 dyn_cast_or_null<InputSectionBase>(Section), Value);
453 template <typename ELFT>
454 void SymbolTable<ELFT>::addShared(SharedFile<ELFT> *File, StringRef Name,
456 const typename ELFT::Verdef *Verdef) {
457 // DSO symbols do not affect visibility in the output, so we pass STV_DEFAULT
458 // as the visibility, which will leave the visibility in the symbol table
462 std::tie(S, WasInserted) = insert(Name, Sym.getType(), STV_DEFAULT,
463 /*CanOmitFromDynSym*/ true, File);
464 // Make sure we preempt DSO symbols with default visibility.
465 if (Sym.getVisibility() == STV_DEFAULT)
466 S->ExportDynamic = true;
468 SymbolBody *Body = S->body();
469 // An undefined symbol with non default visibility must be satisfied
472 (isa<Undefined>(Body) && Body->getVisibility() == STV_DEFAULT)) {
473 replaceBody<SharedSymbol>(S, File, Name, Sym.st_other, Sym.getType(), &Sym,
480 template <class ELFT>
481 Symbol *SymbolTable<ELFT>::addBitcode(StringRef Name, uint8_t Binding,
482 uint8_t StOther, uint8_t Type,
483 bool CanOmitFromDynSym, BitcodeFile *F) {
486 std::tie(S, WasInserted) =
487 insert(Name, Type, getVisibility(StOther), CanOmitFromDynSym, F);
488 int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Binding,
489 /*IsAbs*/ false, /*Value*/ 0);
491 replaceBody<DefinedRegular>(S, Name, /*IsLocal=*/false, StOther, Type, 0, 0,
494 reportDuplicate(S->body(), F);
498 template <class ELFT> SymbolBody *SymbolTable<ELFT>::find(StringRef Name) {
499 auto It = Symtab.find(CachedHashStringRef(Name));
500 if (It == Symtab.end())
502 SymIndex V = It->second;
505 return SymVector[V.Idx]->body();
508 template <class ELFT>
509 SymbolBody *SymbolTable<ELFT>::findInCurrentDSO(StringRef Name) {
510 if (SymbolBody *S = find(Name))
511 if (S->isInCurrentDSO())
516 template <class ELFT>
517 Symbol *SymbolTable<ELFT>::addLazyArchive(ArchiveFile *F,
518 const object::Archive::Symbol Sym) {
521 StringRef Name = Sym.getName();
522 std::tie(S, WasInserted) = insert(Name);
524 replaceBody<LazyArchive>(S, *F, Sym, SymbolBody::UnknownType);
527 if (!S->body()->isUndefined())
530 // Weak undefined symbols should not fetch members from archives. If we were
531 // to keep old symbol we would not know that an archive member was available
532 // if a strong undefined symbol shows up afterwards in the link. If a strong
533 // undefined symbol never shows up, this lazy symbol will get to the end of
534 // the link and must be treated as the weak undefined one. We already marked
535 // this symbol as used when we added it to the symbol table, but we also need
536 // to preserve its type. FIXME: Move the Type field to Symbol.
538 replaceBody<LazyArchive>(S, *F, Sym, S->body()->Type);
541 std::pair<MemoryBufferRef, uint64_t> MBInfo = F->getMember(&Sym);
542 if (!MBInfo.first.getBuffer().empty())
543 addFile(createObjectFile(MBInfo.first, F->getName(), MBInfo.second));
547 template <class ELFT>
548 void SymbolTable<ELFT>::addLazyObject(StringRef Name, LazyObjectFile &Obj) {
551 std::tie(S, WasInserted) = insert(Name);
553 replaceBody<LazyObject>(S, Name, Obj, SymbolBody::UnknownType);
556 if (!S->body()->isUndefined())
559 // See comment for addLazyArchive above.
561 replaceBody<LazyObject>(S, Name, Obj, S->body()->Type);
562 else if (InputFile *F = Obj.fetch())
566 // Process undefined (-u) flags by loading lazy symbols named by those flags.
567 template <class ELFT> void SymbolTable<ELFT>::scanUndefinedFlags() {
568 for (StringRef S : Config->Undefined)
569 if (auto *L = dyn_cast_or_null<Lazy>(find(S)))
570 if (InputFile *File = L->fetch())
574 // This function takes care of the case in which shared libraries depend on
575 // the user program (not the other way, which is usual). Shared libraries
576 // may have undefined symbols, expecting that the user program provides
577 // the definitions for them. An example is BSD's __progname symbol.
578 // We need to put such symbols to the main program's .dynsym so that
579 // shared libraries can find them.
580 // Except this, we ignore undefined symbols in DSOs.
581 template <class ELFT> void SymbolTable<ELFT>::scanShlibUndefined() {
582 for (SharedFile<ELFT> *File : SharedFiles) {
583 for (StringRef U : File->getUndefinedSymbols()) {
584 SymbolBody *Sym = find(U);
585 if (!Sym || !Sym->isDefined())
587 Sym->symbol()->ExportDynamic = true;
589 // If -dynamic-list is given, the default version is set to
590 // VER_NDX_LOCAL, which prevents a symbol to be exported via .dynsym.
591 // Set to VER_NDX_GLOBAL so the symbol will be handled as if it were
592 // specified by -dynamic-list.
593 Sym->symbol()->VersionId = VER_NDX_GLOBAL;
598 // Initialize DemangledSyms with a map from demangled symbols to symbol
599 // objects. Used to handle "extern C++" directive in version scripts.
601 // The map will contain all demangled symbols. That can be very large,
602 // and in LLD we generally want to avoid do anything for each symbol.
603 // Then, why are we doing this? Here's why.
605 // Users can use "extern C++ {}" directive to match against demangled
606 // C++ symbols. For example, you can write a pattern such as
607 // "llvm::*::foo(int, ?)". Obviously, there's no way to handle this
608 // other than trying to match a pattern against all demangled symbols.
609 // So, if "extern C++" feature is used, we need to demangle all known
611 template <class ELFT>
612 StringMap<std::vector<SymbolBody *>> &SymbolTable<ELFT>::getDemangledSyms() {
613 if (!DemangledSyms) {
614 DemangledSyms.emplace();
615 for (Symbol *Sym : SymVector) {
616 SymbolBody *B = Sym->body();
617 if (B->isUndefined())
619 if (Optional<std::string> S = demangle(B->getName()))
620 (*DemangledSyms)[*S].push_back(B);
622 (*DemangledSyms)[B->getName()].push_back(B);
625 return *DemangledSyms;
628 template <class ELFT>
629 std::vector<SymbolBody *> SymbolTable<ELFT>::findByVersion(SymbolVersion Ver) {
631 return getDemangledSyms().lookup(Ver.Name);
632 if (SymbolBody *B = find(Ver.Name))
633 if (!B->isUndefined())
638 template <class ELFT>
639 std::vector<SymbolBody *>
640 SymbolTable<ELFT>::findAllByVersion(SymbolVersion Ver) {
641 std::vector<SymbolBody *> Res;
642 StringMatcher M(Ver.Name);
644 if (Ver.IsExternCpp) {
645 for (auto &P : getDemangledSyms())
646 if (M.match(P.first()))
647 Res.insert(Res.end(), P.second.begin(), P.second.end());
651 for (Symbol *Sym : SymVector) {
652 SymbolBody *B = Sym->body();
653 if (!B->isUndefined() && M.match(B->getName()))
659 // If there's only one anonymous version definition in a version
660 // script file, the script does not actually define any symbol version,
661 // but just specifies symbols visibilities.
662 template <class ELFT> void SymbolTable<ELFT>::handleAnonymousVersion() {
663 for (SymbolVersion &Ver : Config->VersionScriptGlobals)
664 assignExactVersion(Ver, VER_NDX_GLOBAL, "global");
665 for (SymbolVersion &Ver : Config->VersionScriptGlobals)
666 assignWildcardVersion(Ver, VER_NDX_GLOBAL);
667 for (SymbolVersion &Ver : Config->VersionScriptLocals)
668 assignExactVersion(Ver, VER_NDX_LOCAL, "local");
669 for (SymbolVersion &Ver : Config->VersionScriptLocals)
670 assignWildcardVersion(Ver, VER_NDX_LOCAL);
673 // Set symbol versions to symbols. This function handles patterns
674 // containing no wildcard characters.
675 template <class ELFT>
676 void SymbolTable<ELFT>::assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
677 StringRef VersionName) {
681 // Get a list of symbols which we need to assign the version to.
682 std::vector<SymbolBody *> Syms = findByVersion(Ver);
684 if (Config->NoUndefinedVersion)
685 error("version script assignment of '" + VersionName + "' to symbol '" +
686 Ver.Name + "' failed: symbol not defined");
690 // Assign the version.
691 for (SymbolBody *B : Syms) {
692 Symbol *Sym = B->symbol();
693 if (Sym->InVersionScript)
694 warn("duplicate symbol '" + Ver.Name + "' in version script");
695 Sym->VersionId = VersionId;
696 Sym->InVersionScript = true;
700 template <class ELFT>
701 void SymbolTable<ELFT>::assignWildcardVersion(SymbolVersion Ver,
702 uint16_t VersionId) {
703 if (!Ver.HasWildcard)
705 std::vector<SymbolBody *> Syms = findAllByVersion(Ver);
707 // Exact matching takes precendence over fuzzy matching,
708 // so we set a version to a symbol only if no version has been assigned
709 // to the symbol. This behavior is compatible with GNU.
710 for (SymbolBody *B : Syms)
711 if (B->symbol()->VersionId == Config->DefaultSymbolVersion)
712 B->symbol()->VersionId = VersionId;
715 static bool isDefaultVersion(SymbolBody *B) {
716 return B->isInCurrentDSO() && B->getName().find("@@") != StringRef::npos;
719 // This function processes version scripts by updating VersionId
720 // member of symbols.
721 template <class ELFT> void SymbolTable<ELFT>::scanVersionScript() {
722 // Symbol themselves might know their versions because symbols
723 // can contain versions in the form of <name>@<version>.
724 // Let them parse and update their names to exclude version suffix.
725 for (Symbol *Sym : SymVector) {
726 SymbolBody *Body = Sym->body();
727 bool IsDefault = isDefaultVersion(Body);
728 Body->parseSymbolVersion();
733 // <name>@@<version> means the symbol is the default version. If that's the
734 // case, the symbol is not used only to resolve <name> of version <version>
735 // but also undefined unversioned symbols with name <name>.
736 SymbolBody *S = find(Body->getName());
737 if (S && S->isUndefined())
741 // Handle edge cases first.
742 handleAnonymousVersion();
744 if (Config->VersionDefinitions.empty())
747 // Now we have version definitions, so we need to set version ids to symbols.
748 // Each version definition has a glob pattern, and all symbols that match
749 // with the pattern get that version.
751 // First, we assign versions to exact matching symbols,
752 // i.e. version definitions not containing any glob meta-characters.
753 for (VersionDefinition &V : Config->VersionDefinitions)
754 for (SymbolVersion &Ver : V.Globals)
755 assignExactVersion(Ver, V.Id, V.Name);
757 // Next, we assign versions to fuzzy matching symbols,
758 // i.e. version definitions containing glob meta-characters.
759 // Note that because the last match takes precedence over previous matches,
760 // we iterate over the definitions in the reverse order.
761 for (VersionDefinition &V : llvm::reverse(Config->VersionDefinitions))
762 for (SymbolVersion &Ver : V.Globals)
763 assignWildcardVersion(Ver, V.Id);
766 template class elf::SymbolTable<ELF32LE>;
767 template class elf::SymbolTable<ELF32BE>;
768 template class elf::SymbolTable<ELF64LE>;
769 template class elf::SymbolTable<ELF64BE>;