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] = RenamedSymbol{Sym, Real->Binding};
171 Config->RenamedSymbols[Sym] = RenamedSymbol{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] = RenamedSymbol{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 *Sym = KV.first;
197 Symbol *Rename = KV.second.Target;
198 Sym->Binding = KV.second.OrigBinding;
200 // We rename symbols by replacing the old symbol's SymbolBody with the new
201 // symbol's SymbolBody. This causes all SymbolBody pointers referring to the
202 // old symbol to instead refer to the new symbol.
203 memcpy(Sym->Body.buffer, Rename->Body.buffer, sizeof(Sym->Body));
207 static uint8_t getMinVisibility(uint8_t VA, uint8_t VB) {
208 if (VA == STV_DEFAULT)
210 if (VB == STV_DEFAULT)
212 return std::min(VA, VB);
215 // Find an existing symbol or create and insert a new one.
216 template <class ELFT>
217 std::pair<Symbol *, bool> SymbolTable<ELFT>::insert(StringRef Name) {
218 auto P = Symtab.insert(
219 {CachedHashStringRef(Name), SymIndex((int)SymVector.size(), false)});
220 SymIndex &V = P.first->second;
221 bool IsNew = P.second;
225 V = SymIndex((int)SymVector.size(), true);
230 Sym = make<Symbol>();
231 Sym->InVersionScript = false;
232 Sym->Binding = STB_WEAK;
233 Sym->Visibility = STV_DEFAULT;
234 Sym->IsUsedInRegularObj = false;
235 Sym->ExportDynamic = false;
236 Sym->Traced = V.Traced;
237 Sym->VersionId = Config->DefaultSymbolVersion;
238 SymVector.push_back(Sym);
240 Sym = SymVector[V.Idx];
245 // Find an existing symbol or create and insert a new one, then apply the given
247 template <class ELFT>
248 std::pair<Symbol *, bool>
249 SymbolTable<ELFT>::insert(StringRef Name, uint8_t Type, uint8_t Visibility,
250 bool CanOmitFromDynSym, InputFile *File) {
251 bool IsUsedInRegularObj = !File || File->kind() == InputFile::ObjectKind;
254 std::tie(S, WasInserted) = insert(Name);
256 // Merge in the new symbol's visibility.
257 S->Visibility = getMinVisibility(S->Visibility, Visibility);
259 if (!CanOmitFromDynSym && (Config->Shared || Config->ExportDynamic))
260 S->ExportDynamic = true;
262 if (IsUsedInRegularObj)
263 S->IsUsedInRegularObj = true;
265 if (!WasInserted && S->body()->Type != SymbolBody::UnknownType &&
266 ((Type == STT_TLS) != S->body()->isTls())) {
267 error("TLS attribute mismatch: " + toString(*S->body()) +
268 "\n>>> defined in " + toString(S->body()->File) +
269 "\n>>> defined in " + toString(File));
272 return {S, WasInserted};
275 template <class ELFT> Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name) {
276 return addUndefined(Name, /*IsLocal=*/false, STB_GLOBAL, STV_DEFAULT,
278 /*CanOmitFromDynSym*/ false, /*File*/ nullptr);
281 static uint8_t getVisibility(uint8_t StOther) { return StOther & 3; }
283 template <class ELFT>
284 Symbol *SymbolTable<ELFT>::addUndefined(StringRef Name, bool IsLocal,
285 uint8_t Binding, uint8_t StOther,
286 uint8_t Type, bool CanOmitFromDynSym,
290 uint8_t Visibility = getVisibility(StOther);
291 std::tie(S, WasInserted) =
292 insert(Name, Type, Visibility, CanOmitFromDynSym, File);
293 // An undefined symbol with non default visibility must be satisfied
296 (isa<SharedSymbol>(S->body()) && Visibility != STV_DEFAULT)) {
297 S->Binding = Binding;
298 replaceBody<Undefined>(S, Name, IsLocal, StOther, Type, File);
301 if (Binding != STB_WEAK) {
302 SymbolBody *B = S->body();
303 if (B->isShared() || B->isLazy() || B->isUndefined())
304 S->Binding = Binding;
305 if (auto *SS = dyn_cast<SharedSymbol>(B))
306 cast<SharedFile<ELFT>>(SS->File)->IsUsed = true;
308 if (auto *L = dyn_cast<Lazy>(S->body())) {
309 // An undefined weak will not fetch archive members, but we have to remember
310 // its type. See also comment in addLazyArchive.
313 else if (InputFile *F = L->fetch())
319 // We have a new defined symbol with the specified binding. Return 1 if the new
320 // symbol should win, -1 if the new symbol should lose, or 0 if both symbols are
321 // strong defined symbols.
322 static int compareDefined(Symbol *S, bool WasInserted, uint8_t Binding) {
325 SymbolBody *Body = S->body();
326 if (Body->isLazy() || !Body->isInCurrentDSO())
328 if (Binding == STB_WEAK)
335 // We have a new non-common defined symbol with the specified binding. Return 1
336 // if the new symbol should win, -1 if the new symbol should lose, or 0 if there
337 // is a conflict. If the new symbol wins, also update the binding.
338 template <typename ELFT>
339 static int compareDefinedNonCommon(Symbol *S, bool WasInserted, uint8_t Binding,
340 bool IsAbsolute, typename ELFT::uint Value) {
341 if (int Cmp = compareDefined(S, WasInserted, Binding)) {
343 S->Binding = Binding;
346 SymbolBody *B = S->body();
347 if (isa<DefinedCommon>(B)) {
348 // Non-common symbols take precedence over common symbols.
349 if (Config->WarnCommon)
350 warn("common " + S->body()->getName() + " is overridden");
352 } else if (auto *R = dyn_cast<DefinedRegular>(B)) {
353 if (R->Section == nullptr && Binding == STB_GLOBAL && IsAbsolute &&
360 template <class ELFT>
361 Symbol *SymbolTable<ELFT>::addCommon(StringRef N, uint64_t Size,
362 uint32_t Alignment, uint8_t Binding,
363 uint8_t StOther, uint8_t Type,
367 std::tie(S, WasInserted) = insert(N, Type, getVisibility(StOther),
368 /*CanOmitFromDynSym*/ false, File);
369 int Cmp = compareDefined(S, WasInserted, Binding);
371 S->Binding = Binding;
372 replaceBody<DefinedCommon>(S, N, Size, Alignment, StOther, Type, File);
373 } else if (Cmp == 0) {
374 auto *C = dyn_cast<DefinedCommon>(S->body());
376 // Non-common symbols take precedence over common symbols.
377 if (Config->WarnCommon)
378 warn("common " + S->body()->getName() + " is overridden");
382 if (Config->WarnCommon)
383 warn("multiple common of " + S->body()->getName());
385 Alignment = C->Alignment = std::max(C->Alignment, Alignment);
387 replaceBody<DefinedCommon>(S, N, Size, Alignment, StOther, Type, File);
392 static void warnOrError(const Twine &Msg) {
393 if (Config->AllowMultipleDefinition)
399 static void reportDuplicate(SymbolBody *Sym, InputFile *NewFile) {
400 warnOrError("duplicate symbol: " + toString(*Sym) +
401 "\n>>> defined in " + toString(Sym->File) +
402 "\n>>> defined in " + toString(NewFile));
405 template <class ELFT>
406 static void reportDuplicate(SymbolBody *Sym, InputSectionBase *ErrSec,
407 typename ELFT::uint ErrOffset) {
408 DefinedRegular *D = dyn_cast<DefinedRegular>(Sym);
409 if (!D || !D->Section || !ErrSec) {
410 reportDuplicate(Sym, ErrSec ? ErrSec->getFile<ELFT>() : nullptr);
414 // Construct and print an error message in the form of:
416 // ld.lld: error: duplicate symbol: foo
417 // >>> defined at bar.c:30
418 // >>> bar.o (/home/alice/src/bar.o)
419 // >>> defined at baz.c:563
420 // >>> baz.o in archive libbaz.a
421 auto *Sec1 = cast<InputSectionBase>(D->Section);
422 std::string Src1 = Sec1->getSrcMsg<ELFT>(D->Value);
423 std::string Obj1 = Sec1->getObjMsg<ELFT>(D->Value);
424 std::string Src2 = ErrSec->getSrcMsg<ELFT>(ErrOffset);
425 std::string Obj2 = ErrSec->getObjMsg<ELFT>(ErrOffset);
427 std::string Msg = "duplicate symbol: " + toString(*Sym) + "\n>>> defined at ";
429 Msg += Src1 + "\n>>> ";
430 Msg += Obj1 + "\n>>> defined at ";
432 Msg += Src2 + "\n>>> ";
437 template <typename ELFT>
438 Symbol *SymbolTable<ELFT>::addRegular(StringRef Name, uint8_t StOther,
439 uint8_t Type, uint64_t Value,
440 uint64_t Size, uint8_t Binding,
441 SectionBase *Section, InputFile *File) {
444 std::tie(S, WasInserted) = insert(Name, Type, getVisibility(StOther),
445 /*CanOmitFromDynSym*/ false, File);
446 int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Binding,
447 Section == nullptr, Value);
449 replaceBody<DefinedRegular>(S, Name, /*IsLocal=*/false, StOther, Type,
450 Value, Size, Section, File);
452 reportDuplicate<ELFT>(S->body(),
453 dyn_cast_or_null<InputSectionBase>(Section), Value);
457 template <typename ELFT>
458 void SymbolTable<ELFT>::addShared(SharedFile<ELFT> *File, StringRef Name,
460 const typename ELFT::Verdef *Verdef) {
461 // DSO symbols do not affect visibility in the output, so we pass STV_DEFAULT
462 // as the visibility, which will leave the visibility in the symbol table
466 std::tie(S, WasInserted) = insert(Name, Sym.getType(), STV_DEFAULT,
467 /*CanOmitFromDynSym*/ true, File);
468 // Make sure we preempt DSO symbols with default visibility.
469 if (Sym.getVisibility() == STV_DEFAULT)
470 S->ExportDynamic = true;
472 SymbolBody *Body = S->body();
473 // An undefined symbol with non default visibility must be satisfied
476 (isa<Undefined>(Body) && Body->getVisibility() == STV_DEFAULT)) {
477 replaceBody<SharedSymbol>(S, File, Name, Sym.st_other, Sym.getType(), &Sym,
484 template <class ELFT>
485 Symbol *SymbolTable<ELFT>::addBitcode(StringRef Name, uint8_t Binding,
486 uint8_t StOther, uint8_t Type,
487 bool CanOmitFromDynSym, BitcodeFile *F) {
490 std::tie(S, WasInserted) =
491 insert(Name, Type, getVisibility(StOther), CanOmitFromDynSym, F);
492 int Cmp = compareDefinedNonCommon<ELFT>(S, WasInserted, Binding,
493 /*IsAbs*/ false, /*Value*/ 0);
495 replaceBody<DefinedRegular>(S, Name, /*IsLocal=*/false, StOther, Type, 0, 0,
498 reportDuplicate(S->body(), F);
502 template <class ELFT> SymbolBody *SymbolTable<ELFT>::find(StringRef Name) {
503 auto It = Symtab.find(CachedHashStringRef(Name));
504 if (It == Symtab.end())
506 SymIndex V = It->second;
509 return SymVector[V.Idx]->body();
512 template <class ELFT>
513 SymbolBody *SymbolTable<ELFT>::findInCurrentDSO(StringRef Name) {
514 if (SymbolBody *S = find(Name))
515 if (S->isInCurrentDSO())
520 template <class ELFT>
521 void SymbolTable<ELFT>::addLazyArchive(ArchiveFile *F,
522 const object::Archive::Symbol Sym) {
525 StringRef Name = Sym.getName();
526 std::tie(S, WasInserted) = insert(Name);
528 replaceBody<LazyArchive>(S, *F, Sym, SymbolBody::UnknownType);
531 if (!S->body()->isUndefined())
534 // Weak undefined symbols should not fetch members from archives. If we were
535 // to keep old symbol we would not know that an archive member was available
536 // if a strong undefined symbol shows up afterwards in the link. If a strong
537 // undefined symbol never shows up, this lazy symbol will get to the end of
538 // the link and must be treated as the weak undefined one. We already marked
539 // this symbol as used when we added it to the symbol table, but we also need
540 // to preserve its type. FIXME: Move the Type field to Symbol.
542 replaceBody<LazyArchive>(S, *F, Sym, S->body()->Type);
545 std::pair<MemoryBufferRef, uint64_t> MBInfo = F->getMember(&Sym);
546 if (!MBInfo.first.getBuffer().empty())
547 addFile(createObjectFile(MBInfo.first, F->getName(), MBInfo.second));
550 template <class ELFT>
551 void SymbolTable<ELFT>::addLazyObject(StringRef Name, LazyObjectFile &Obj) {
554 std::tie(S, WasInserted) = insert(Name);
556 replaceBody<LazyObject>(S, Name, Obj, SymbolBody::UnknownType);
559 if (!S->body()->isUndefined())
562 // See comment for addLazyArchive above.
564 replaceBody<LazyObject>(S, Name, Obj, S->body()->Type);
565 else if (InputFile *F = Obj.fetch())
569 // Process undefined (-u) flags by loading lazy symbols named by those flags.
570 template <class ELFT> void SymbolTable<ELFT>::scanUndefinedFlags() {
571 for (StringRef S : Config->Undefined)
572 if (auto *L = dyn_cast_or_null<Lazy>(find(S)))
573 if (InputFile *File = L->fetch())
577 // This function takes care of the case in which shared libraries depend on
578 // the user program (not the other way, which is usual). Shared libraries
579 // may have undefined symbols, expecting that the user program provides
580 // the definitions for them. An example is BSD's __progname symbol.
581 // We need to put such symbols to the main program's .dynsym so that
582 // shared libraries can find them.
583 // Except this, we ignore undefined symbols in DSOs.
584 template <class ELFT> void SymbolTable<ELFT>::scanShlibUndefined() {
585 for (SharedFile<ELFT> *File : SharedFiles) {
586 for (StringRef U : File->getUndefinedSymbols()) {
587 SymbolBody *Sym = find(U);
588 if (!Sym || !Sym->isDefined())
590 Sym->symbol()->ExportDynamic = true;
592 // If -dynamic-list is given, the default version is set to
593 // VER_NDX_LOCAL, which prevents a symbol to be exported via .dynsym.
594 // Set to VER_NDX_GLOBAL so the symbol will be handled as if it were
595 // specified by -dynamic-list.
596 Sym->symbol()->VersionId = VER_NDX_GLOBAL;
601 // Initialize DemangledSyms with a map from demangled symbols to symbol
602 // objects. Used to handle "extern C++" directive in version scripts.
604 // The map will contain all demangled symbols. That can be very large,
605 // and in LLD we generally want to avoid do anything for each symbol.
606 // Then, why are we doing this? Here's why.
608 // Users can use "extern C++ {}" directive to match against demangled
609 // C++ symbols. For example, you can write a pattern such as
610 // "llvm::*::foo(int, ?)". Obviously, there's no way to handle this
611 // other than trying to match a pattern against all demangled symbols.
612 // So, if "extern C++" feature is used, we need to demangle all known
614 template <class ELFT>
615 StringMap<std::vector<SymbolBody *>> &SymbolTable<ELFT>::getDemangledSyms() {
616 if (!DemangledSyms) {
617 DemangledSyms.emplace();
618 for (Symbol *Sym : SymVector) {
619 SymbolBody *B = Sym->body();
620 if (B->isUndefined())
622 if (Optional<std::string> S = demangle(B->getName()))
623 (*DemangledSyms)[*S].push_back(B);
625 (*DemangledSyms)[B->getName()].push_back(B);
628 return *DemangledSyms;
631 template <class ELFT>
632 std::vector<SymbolBody *> SymbolTable<ELFT>::findByVersion(SymbolVersion Ver) {
634 return getDemangledSyms().lookup(Ver.Name);
635 if (SymbolBody *B = find(Ver.Name))
636 if (!B->isUndefined())
641 template <class ELFT>
642 std::vector<SymbolBody *>
643 SymbolTable<ELFT>::findAllByVersion(SymbolVersion Ver) {
644 std::vector<SymbolBody *> Res;
645 StringMatcher M(Ver.Name);
647 if (Ver.IsExternCpp) {
648 for (auto &P : getDemangledSyms())
649 if (M.match(P.first()))
650 Res.insert(Res.end(), P.second.begin(), P.second.end());
654 for (Symbol *Sym : SymVector) {
655 SymbolBody *B = Sym->body();
656 if (!B->isUndefined() && M.match(B->getName()))
662 // If there's only one anonymous version definition in a version
663 // script file, the script does not actually define any symbol version,
664 // but just specifies symbols visibilities.
665 template <class ELFT> void SymbolTable<ELFT>::handleAnonymousVersion() {
666 for (SymbolVersion &Ver : Config->VersionScriptGlobals)
667 assignExactVersion(Ver, VER_NDX_GLOBAL, "global");
668 for (SymbolVersion &Ver : Config->VersionScriptGlobals)
669 assignWildcardVersion(Ver, VER_NDX_GLOBAL);
670 for (SymbolVersion &Ver : Config->VersionScriptLocals)
671 assignExactVersion(Ver, VER_NDX_LOCAL, "local");
672 for (SymbolVersion &Ver : Config->VersionScriptLocals)
673 assignWildcardVersion(Ver, VER_NDX_LOCAL);
676 // Set symbol versions to symbols. This function handles patterns
677 // containing no wildcard characters.
678 template <class ELFT>
679 void SymbolTable<ELFT>::assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
680 StringRef VersionName) {
684 // Get a list of symbols which we need to assign the version to.
685 std::vector<SymbolBody *> Syms = findByVersion(Ver);
687 if (Config->NoUndefinedVersion)
688 error("version script assignment of '" + VersionName + "' to symbol '" +
689 Ver.Name + "' failed: symbol not defined");
693 // Assign the version.
694 for (SymbolBody *B : Syms) {
695 Symbol *Sym = B->symbol();
696 if (Sym->InVersionScript)
697 warn("duplicate symbol '" + Ver.Name + "' in version script");
698 Sym->VersionId = VersionId;
699 Sym->InVersionScript = true;
703 template <class ELFT>
704 void SymbolTable<ELFT>::assignWildcardVersion(SymbolVersion Ver,
705 uint16_t VersionId) {
706 if (!Ver.HasWildcard)
708 std::vector<SymbolBody *> Syms = findAllByVersion(Ver);
710 // Exact matching takes precendence over fuzzy matching,
711 // so we set a version to a symbol only if no version has been assigned
712 // to the symbol. This behavior is compatible with GNU.
713 for (SymbolBody *B : Syms)
714 if (B->symbol()->VersionId == Config->DefaultSymbolVersion)
715 B->symbol()->VersionId = VersionId;
718 // This function processes version scripts by updating VersionId
719 // member of symbols.
720 template <class ELFT> void SymbolTable<ELFT>::scanVersionScript() {
721 // Symbol themselves might know their versions because symbols
722 // can contain versions in the form of <name>@<version>.
723 // Let them parse their names.
724 if (!Config->VersionDefinitions.empty())
725 for (Symbol *Sym : SymVector)
726 Sym->body()->parseSymbolVersion();
728 // Handle edge cases first.
729 handleAnonymousVersion();
731 if (Config->VersionDefinitions.empty())
734 // Now we have version definitions, so we need to set version ids to symbols.
735 // Each version definition has a glob pattern, and all symbols that match
736 // with the pattern get that version.
738 // First, we assign versions to exact matching symbols,
739 // i.e. version definitions not containing any glob meta-characters.
740 for (VersionDefinition &V : Config->VersionDefinitions)
741 for (SymbolVersion &Ver : V.Globals)
742 assignExactVersion(Ver, V.Id, V.Name);
744 // Next, we assign versions to fuzzy matching symbols,
745 // i.e. version definitions containing glob meta-characters.
746 // Note that because the last match takes precedence over previous matches,
747 // we iterate over the definitions in the reverse order.
748 for (VersionDefinition &V : llvm::reverse(Config->VersionDefinitions))
749 for (SymbolVersion &Ver : V.Globals)
750 assignWildcardVersion(Ver, V.Id);
753 template class elf::SymbolTable<ELF32LE>;
754 template class elf::SymbolTable<ELF32BE>;
755 template class elf::SymbolTable<ELF64LE>;
756 template class elf::SymbolTable<ELF64BE>;