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hanchenye-llvm-project/lld/ELF/SymbolTable.cpp

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//===- SymbolTable.cpp ----------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Symbol table is a bag of all known symbols. We put all symbols of
// all input files to the symbol table. The symbol table is basically
// a hash table with the logic to resolve symbol name conflicts using
// the symbol types.
//
//===----------------------------------------------------------------------===//
#include "SymbolTable.h"
#include "Config.h"
#include "LinkerScript.h"
#include "Memory.h"
#include "Symbols.h"
#include "lld/Common/ErrorHandler.h"
#include "llvm/ADT/STLExtras.h"
using namespace llvm;
using namespace llvm::object;
using namespace llvm::ELF;
using namespace lld;
using namespace lld::elf;
SymbolTable *elf::Symtab;
static InputFile *getFirstElf() {
if (!ObjectFiles.empty())
return ObjectFiles[0];
if (!SharedFiles.empty())
return SharedFiles[0];
return nullptr;
}
// All input object files must be for the same architecture
// (e.g. it does not make sense to link x86 object files with
// MIPS object files.) This function checks for that error.
template <class ELFT> static bool isCompatible(InputFile *F) {
if (!isa<ELFFileBase<ELFT>>(F) && !isa<BitcodeFile>(F))
return true;
if (F->EKind == Config->EKind && F->EMachine == Config->EMachine) {
if (Config->EMachine != EM_MIPS)
return true;
if (isMipsN32Abi(F) == Config->MipsN32Abi)
return true;
}
if (!Config->Emulation.empty())
error(toString(F) + " is incompatible with " + Config->Emulation);
else
error(toString(F) + " is incompatible with " + toString(getFirstElf()));
return false;
}
// Add symbols in File to the symbol table.
template <class ELFT> void SymbolTable::addFile(InputFile *File) {
if (!isCompatible<ELFT>(File))
return;
// Binary file
if (auto *F = dyn_cast<BinaryFile>(File)) {
BinaryFiles.push_back(F);
F->parse<ELFT>();
return;
}
// .a file
if (auto *F = dyn_cast<ArchiveFile>(File)) {
F->parse<ELFT>();
return;
}
// Lazy object file
if (auto *F = dyn_cast<LazyObjFile>(File)) {
F->parse<ELFT>();
return;
}
if (Config->Trace)
message(toString(File));
// .so file
if (auto *F = dyn_cast<SharedFile<ELFT>>(File)) {
// DSOs are uniquified not by filename but by soname.
F->parseSoName();
if (errorCount() || !SoNames.insert(F->SoName).second)
return;
SharedFiles.push_back(F);
F->parseRest();
return;
}
// LLVM bitcode file
if (auto *F = dyn_cast<BitcodeFile>(File)) {
BitcodeFiles.push_back(F);
F->parse<ELFT>(ComdatGroups);
return;
}
// Regular object file
ObjectFiles.push_back(File);
cast<ObjFile<ELFT>>(File)->parse(ComdatGroups);
}
// This function is where all the optimizations of link-time
// optimization happens. When LTO is in use, some input files are
// not in native object file format but in the LLVM bitcode format.
// This function compiles bitcode files into a few big native files
// using LLVM functions and replaces bitcode symbols with the results.
// Because all bitcode files that consist of a program are passed
// to the compiler at once, it can do whole-program optimization.
template <class ELFT> void SymbolTable::addCombinedLTOObject() {
if (BitcodeFiles.empty())
return;
// Compile bitcode files and replace bitcode symbols.
LTO.reset(new BitcodeCompiler);
for (BitcodeFile *F : BitcodeFiles)
LTO->add(*F);
for (InputFile *File : LTO->compile()) {
DenseSet<CachedHashStringRef> DummyGroups;
cast<ObjFile<ELFT>>(File)->parse(DummyGroups);
ObjectFiles.push_back(File);
}
}
template <class ELFT>
DefinedRegular *SymbolTable::addAbsolute(StringRef Name, uint8_t Visibility,
uint8_t Binding) {
Symbol *Sym = addRegular<ELFT>(Name, Visibility, STT_NOTYPE, 0, 0, Binding,
nullptr, nullptr);
return cast<DefinedRegular>(Sym->body());
}
// Set a flag for --trace-symbol so that we can print out a log message
// if a new symbol with the same name is inserted into the symbol table.
void SymbolTable::trace(StringRef Name) {
Symtab.insert({CachedHashStringRef(Name), {-1, true}});
}
// Rename SYM as __wrap_SYM. The original symbol is preserved as __real_SYM.
// Used to implement --wrap.
template <class ELFT> void SymbolTable::addSymbolWrap(StringRef Name) {
SymbolBody *B = find(Name);
if (!B)
return;
Symbol *Sym = B->symbol();
Symbol *Real = addUndefined<ELFT>(Saver.save("__real_" + Name));
Symbol *Wrap = addUndefined<ELFT>(Saver.save("__wrap_" + Name));
defsym(Real, Sym);
defsym(Sym, Wrap);
WrapSymbols.push_back({Wrap, Real});
}
// Creates alias for symbol. Used to implement --defsym=ALIAS=SYM.
template <class ELFT>
void SymbolTable::addSymbolAlias(StringRef Alias, StringRef Name) {
SymbolBody *B = find(Name);
if (!B) {
error("-defsym: undefined symbol: " + Name);
return;
}
defsym(addUndefined<ELFT>(Alias), B->symbol());
}
// Apply symbol renames created by -wrap and -defsym. The renames are created
// before LTO in addSymbolWrap() and addSymbolAlias() to have a chance to inform
// LTO (if LTO is running) not to include these symbols in IPO. Now that the
// symbols are finalized, we can perform the replacement.
void SymbolTable::applySymbolRenames() {
// This function rotates 3 symbols:
//
// __real_foo becomes foo
// foo becomes __wrap_foo
// __wrap_foo becomes __real_foo
//
// The last part is special in that we don't want to change what references to
// __wrap_foo point to, we just want have __real_foo in the symbol table.
// First make a copy of __real_foo
std::vector<Symbol> Origs;
for (const auto &P : WrapSymbols)
Origs.push_back(*P.second);
// Replace __real_foo with foo and foo with __wrap_foo
for (SymbolRenaming &S : Defsyms) {
S.Dst->body()->copyFrom(S.Src->body());
S.Dst->File = S.Src->File;
S.Dst->Binding = S.Binding;
}
// Hide one of the copies of __wrap_foo, create a new symbol and copy
// __real_foo into it.
for (unsigned I = 0, N = WrapSymbols.size(); I < N; ++I) {
// We now have two copies of __wrap_foo. Drop one.
Symbol *Wrap = WrapSymbols[I].first;
Wrap->IsUsedInRegularObj = false;
Symbol *Real = &Origs[I];
// If __real_foo was undefined, we don't want it in the symbol table.
if (!Real->body()->isInCurrentDSO())
continue;
auto *NewSym = make<Symbol>();
memcpy(NewSym, Real, sizeof(Symbol));
SymVector.push_back(NewSym);
}
}
static uint8_t getMinVisibility(uint8_t VA, uint8_t VB) {
if (VA == STV_DEFAULT)
return VB;
if (VB == STV_DEFAULT)
return VA;
return std::min(VA, VB);
}
// Find an existing symbol or create and insert a new one.
std::pair<Symbol *, bool> SymbolTable::insert(StringRef Name) {
// <name>@@<version> means the symbol is the default version. In that
// case <name>@@<version> will be used to resolve references to <name>.
//
// Since this is a hot path, the following string search code is
// optimized for speed. StringRef::find(char) is much faster than
// StringRef::find(StringRef).
size_t Pos = Name.find('@');
if (Pos != StringRef::npos && Pos + 1 < Name.size() && Name[Pos + 1] == '@')
Name = Name.take_front(Pos);
auto P = Symtab.insert(
{CachedHashStringRef(Name), SymIndex((int)SymVector.size(), false)});
SymIndex &V = P.first->second;
bool IsNew = P.second;
if (V.Idx == -1) {
IsNew = true;
V = SymIndex((int)SymVector.size(), true);
}
Symbol *Sym;
if (IsNew) {
Sym = make<Symbol>();
Sym->InVersionScript = false;
Sym->Binding = STB_WEAK;
Sym->Visibility = STV_DEFAULT;
Sym->IsUsedInRegularObj = false;
Sym->ExportDynamic = false;
Sym->CanInline = true;
Sym->Traced = V.Traced;
Sym->VersionId = Config->DefaultSymbolVersion;
SymVector.push_back(Sym);
} else {
Sym = SymVector[V.Idx];
}
return {Sym, IsNew};
}
// Find an existing symbol or create and insert a new one, then apply the given
// attributes.
std::pair<Symbol *, bool> SymbolTable::insert(StringRef Name, uint8_t Type,
uint8_t Visibility,
bool CanOmitFromDynSym,
InputFile *File) {
bool IsUsedInRegularObj = !File || File->kind() == InputFile::ObjKind;
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name);
// Merge in the new symbol's visibility.
S->Visibility = getMinVisibility(S->Visibility, Visibility);
if (!CanOmitFromDynSym && (Config->Shared || Config->ExportDynamic))
S->ExportDynamic = true;
if (IsUsedInRegularObj)
S->IsUsedInRegularObj = true;
if (!WasInserted && S->body()->Type != SymbolBody::UnknownType &&
((Type == STT_TLS) != S->body()->isTls())) {
error("TLS attribute mismatch: " + toString(*S->body()) +
"\n>>> defined in " + toString(S->File) + "\n>>> defined in " +
toString(File));
}
return {S, WasInserted};
}
template <class ELFT> Symbol *SymbolTable::addUndefined(StringRef Name) {
return addUndefined<ELFT>(Name, /*IsLocal=*/false, STB_GLOBAL, STV_DEFAULT,
/*Type*/ 0,
/*CanOmitFromDynSym*/ false, /*File*/ nullptr);
}
static uint8_t getVisibility(uint8_t StOther) { return StOther & 3; }
template <class ELFT>
Symbol *SymbolTable::addUndefined(StringRef Name, bool IsLocal, uint8_t Binding,
uint8_t StOther, uint8_t Type,
bool CanOmitFromDynSym, InputFile *File) {
Symbol *S;
bool WasInserted;
uint8_t Visibility = getVisibility(StOther);
std::tie(S, WasInserted) =
insert(Name, Type, Visibility, CanOmitFromDynSym, File);
// An undefined symbol with non default visibility must be satisfied
// in the same DSO.
if (WasInserted ||
(isa<SharedSymbol>(S->body()) && Visibility != STV_DEFAULT)) {
S->Binding = Binding;
replaceBody<Undefined>(S, File, Name, IsLocal, StOther, Type);
return S;
}
if (Binding != STB_WEAK) {
SymbolBody *B = S->body();
if (!B->isInCurrentDSO())
S->Binding = Binding;
if (auto *SS = dyn_cast<SharedSymbol>(B))
SS->getFile<ELFT>()->IsUsed = true;
}
if (auto *L = dyn_cast<Lazy>(S->body())) {
// An undefined weak will not fetch archive members. See comment on Lazy in
// Symbols.h for the details.
if (S->isWeak())
L->Type = Type;
else if (InputFile *F = L->fetch())
addFile<ELFT>(F);
}
return S;
}
// Using .symver foo,foo@@VER unfortunately creates two symbols: foo and
// foo@@VER. We want to effectively ignore foo, so give precedence to
// foo@@VER.
// FIXME: If users can transition to using
// .symver foo,foo@@@VER
// we can delete this hack.
static int compareVersion(Symbol *S, StringRef Name) {
bool A = Name.contains("@@");
bool B = S->body()->getName().contains("@@");
if (A && !B)
return 1;
if (!A && B)
return -1;
return 0;
}
// We have a new defined symbol with the specified binding. Return 1 if the new
// symbol should win, -1 if the new symbol should lose, or 0 if both symbols are
// strong defined symbols.
static int compareDefined(Symbol *S, bool WasInserted, uint8_t Binding,
StringRef Name) {
if (WasInserted)
return 1;
SymbolBody *Body = S->body();
if (!Body->isInCurrentDSO())
return 1;
if (int R = compareVersion(S, Name))
return R;
if (Binding == STB_WEAK)
return -1;
if (S->isWeak())
return 1;
return 0;
}
// We have a new non-common defined symbol with the specified binding. Return 1
// if the new symbol should win, -1 if the new symbol should lose, or 0 if there
// is a conflict. If the new symbol wins, also update the binding.
static int compareDefinedNonCommon(Symbol *S, bool WasInserted, uint8_t Binding,
bool IsAbsolute, uint64_t Value,
StringRef Name) {
if (int Cmp = compareDefined(S, WasInserted, Binding, Name)) {
if (Cmp > 0)
S->Binding = Binding;
return Cmp;
}
SymbolBody *B = S->body();
if (isa<DefinedCommon>(B)) {
// Non-common symbols take precedence over common symbols.
if (Config->WarnCommon)
warn("common " + S->body()->getName() + " is overridden");
return 1;
} else if (auto *R = dyn_cast<DefinedRegular>(B)) {
if (R->Section == nullptr && Binding == STB_GLOBAL && IsAbsolute &&
R->Value == Value)
return -1;
}
return 0;
}
Symbol *SymbolTable::addCommon(StringRef N, uint64_t Size, uint32_t Alignment,
uint8_t Binding, uint8_t StOther, uint8_t Type,
InputFile *File) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(N, Type, getVisibility(StOther),
/*CanOmitFromDynSym*/ false, File);
int Cmp = compareDefined(S, WasInserted, Binding, N);
if (Cmp > 0) {
S->Binding = Binding;
replaceBody<DefinedCommon>(S, File, N, Size, Alignment, StOther, Type);
} else if (Cmp == 0) {
auto *C = dyn_cast<DefinedCommon>(S->body());
if (!C) {
// Non-common symbols take precedence over common symbols.
if (Config->WarnCommon)
warn("common " + S->body()->getName() + " is overridden");
return S;
}
if (Config->WarnCommon)
warn("multiple common of " + S->body()->getName());
Alignment = C->Alignment = std::max(C->Alignment, Alignment);
if (Size > C->Size)
replaceBody<DefinedCommon>(S, File, N, Size, Alignment, StOther, Type);
}
return S;
}
static void warnOrError(const Twine &Msg) {
if (Config->AllowMultipleDefinition)
warn(Msg);
else
error(Msg);
}
static void reportDuplicate(SymbolBody *Sym, InputFile *NewFile) {
warnOrError("duplicate symbol: " + toString(*Sym) + "\n>>> defined in " +
toString(Sym->getFile()) + "\n>>> defined in " +
toString(NewFile));
}
template <class ELFT>
static void reportDuplicate(SymbolBody *Sym, InputSectionBase *ErrSec,
typename ELFT::uint ErrOffset) {
DefinedRegular *D = dyn_cast<DefinedRegular>(Sym);
if (!D || !D->Section || !ErrSec) {
reportDuplicate(Sym, ErrSec ? ErrSec->File : nullptr);
return;
}
// Construct and print an error message in the form of:
//
// ld.lld: error: duplicate symbol: foo
// >>> defined at bar.c:30
// >>> bar.o (/home/alice/src/bar.o)
// >>> defined at baz.c:563
// >>> baz.o in archive libbaz.a
auto *Sec1 = cast<InputSectionBase>(D->Section);
std::string Src1 = Sec1->getSrcMsg<ELFT>(D->Value);
std::string Obj1 = Sec1->getObjMsg(D->Value);
std::string Src2 = ErrSec->getSrcMsg<ELFT>(ErrOffset);
std::string Obj2 = ErrSec->getObjMsg(ErrOffset);
std::string Msg = "duplicate symbol: " + toString(*Sym) + "\n>>> defined at ";
if (!Src1.empty())
Msg += Src1 + "\n>>> ";
Msg += Obj1 + "\n>>> defined at ";
if (!Src2.empty())
Msg += Src2 + "\n>>> ";
Msg += Obj2;
warnOrError(Msg);
}
template <typename ELFT>
Symbol *SymbolTable::addRegular(StringRef Name, uint8_t StOther, uint8_t Type,
uint64_t Value, uint64_t Size, uint8_t Binding,
SectionBase *Section, InputFile *File) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name, Type, getVisibility(StOther),
/*CanOmitFromDynSym*/ false, File);
int Cmp = compareDefinedNonCommon(S, WasInserted, Binding, Section == nullptr,
Value, Name);
if (Cmp > 0)
replaceBody<DefinedRegular>(S, File, Name, /*IsLocal=*/false, StOther, Type,
Value, Size, Section);
else if (Cmp == 0)
reportDuplicate<ELFT>(S->body(),
dyn_cast_or_null<InputSectionBase>(Section), Value);
return S;
}
template <typename ELFT>
void SymbolTable::addShared(StringRef Name, SharedFile<ELFT> *File,
const typename ELFT::Sym &Sym,
const typename ELFT::Verdef *Verdef) {
// DSO symbols do not affect visibility in the output, so we pass STV_DEFAULT
// as the visibility, which will leave the visibility in the symbol table
// unchanged.
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name, Sym.getType(), STV_DEFAULT,
/*CanOmitFromDynSym*/ true, File);
// Make sure we preempt DSO symbols with default visibility.
if (Sym.getVisibility() == STV_DEFAULT)
S->ExportDynamic = true;
SymbolBody *Body = S->body();
// An undefined symbol with non default visibility must be satisfied
// in the same DSO.
if (WasInserted || ((Body->isUndefined() || Body->isLazy()) &&
Body->getVisibility() == STV_DEFAULT)) {
replaceBody<SharedSymbol>(S, File, Name, Sym.st_other, Sym.getType(), &Sym,
Verdef);
if (!S->isWeak())
File->IsUsed = true;
}
}
Symbol *SymbolTable::addBitcode(StringRef Name, uint8_t Binding,
uint8_t StOther, uint8_t Type,
bool CanOmitFromDynSym, BitcodeFile *F) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) =
insert(Name, Type, getVisibility(StOther), CanOmitFromDynSym, F);
int Cmp = compareDefinedNonCommon(S, WasInserted, Binding,
/*IsAbs*/ false, /*Value*/ 0, Name);
if (Cmp > 0)
replaceBody<DefinedRegular>(S, F, Name, /*IsLocal=*/false, StOther, Type, 0,
0, nullptr);
else if (Cmp == 0)
reportDuplicate(S->body(), F);
return S;
}
SymbolBody *SymbolTable::find(StringRef Name) {
auto It = Symtab.find(CachedHashStringRef(Name));
if (It == Symtab.end())
return nullptr;
SymIndex V = It->second;
if (V.Idx == -1)
return nullptr;
return SymVector[V.Idx]->body();
}
void SymbolTable::defsym(Symbol *Dst, Symbol *Src) {
// We want to tell LTO not to inline Dst symbol because LTO doesn't
// know the final symbol contents after renaming.
Dst->CanInline = false;
// Tell LTO not to eliminate this symbol.
Src->IsUsedInRegularObj = true;
Defsyms.push_back({Dst, Src, Dst->Binding});
}
template <class ELFT>
Symbol *SymbolTable::addLazyArchive(StringRef Name, ArchiveFile *F,
const object::Archive::Symbol Sym) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name);
if (WasInserted) {
replaceBody<LazyArchive>(S, F, Sym, SymbolBody::UnknownType);
return S;
}
if (!S->body()->isUndefined())
return S;
// An undefined weak will not fetch archive members. See comment on Lazy in
// Symbols.h for the details.
if (S->isWeak()) {
replaceBody<LazyArchive>(S, F, Sym, S->body()->Type);
return S;
}
std::pair<MemoryBufferRef, uint64_t> MBInfo = F->getMember(&Sym);
if (!MBInfo.first.getBuffer().empty())
addFile<ELFT>(createObjectFile(MBInfo.first, F->getName(), MBInfo.second));
return S;
}
template <class ELFT>
void SymbolTable::addLazyObject(StringRef Name, LazyObjFile &Obj) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name);
if (WasInserted) {
replaceBody<LazyObject>(S, &Obj, Name, SymbolBody::UnknownType);
return;
}
if (!S->body()->isUndefined())
return;
// See comment for addLazyArchive above.
if (S->isWeak())
replaceBody<LazyObject>(S, &Obj, Name, S->body()->Type);
else if (InputFile *F = Obj.fetch())
addFile<ELFT>(F);
}
// If we already saw this symbol, force loading its file.
template <class ELFT> void SymbolTable::fetchIfLazy(StringRef Name) {
if (SymbolBody *B = find(Name)) {
// Mark the symbol not to be eliminated by LTO
// even if it is a bitcode symbol.
B->symbol()->IsUsedInRegularObj = true;
if (auto *L = dyn_cast_or_null<Lazy>(B))
if (InputFile *File = L->fetch())
addFile<ELFT>(File);
}
}
// This function takes care of the case in which shared libraries depend on
// the user program (not the other way, which is usual). Shared libraries
// may have undefined symbols, expecting that the user program provides
// the definitions for them. An example is BSD's __progname symbol.
// We need to put such symbols to the main program's .dynsym so that
// shared libraries can find them.
// Except this, we ignore undefined symbols in DSOs.
template <class ELFT> void SymbolTable::scanShlibUndefined() {
for (InputFile *F : SharedFiles) {
for (StringRef U : cast<SharedFile<ELFT>>(F)->getUndefinedSymbols()) {
SymbolBody *Sym = find(U);
if (!Sym || !Sym->isDefined())
continue;
Sym->symbol()->ExportDynamic = true;
// If -dynamic-list is given, the default version is set to
// VER_NDX_LOCAL, which prevents a symbol to be exported via .dynsym.
// Set to VER_NDX_GLOBAL so the symbol will be handled as if it were
// specified by -dynamic-list.
Sym->symbol()->VersionId = VER_NDX_GLOBAL;
}
}
}
// Initialize DemangledSyms with a map from demangled symbols to symbol
// objects. Used to handle "extern C++" directive in version scripts.
//
// The map will contain all demangled symbols. That can be very large,
// and in LLD we generally want to avoid do anything for each symbol.
// Then, why are we doing this? Here's why.
//
// Users can use "extern C++ {}" directive to match against demangled
// C++ symbols. For example, you can write a pattern such as
// "llvm::*::foo(int, ?)". Obviously, there's no way to handle this
// other than trying to match a pattern against all demangled symbols.
// So, if "extern C++" feature is used, we need to demangle all known
// symbols.
StringMap<std::vector<SymbolBody *>> &SymbolTable::getDemangledSyms() {
if (!DemangledSyms) {
DemangledSyms.emplace();
for (Symbol *Sym : SymVector) {
SymbolBody *B = Sym->body();
if (!B->isInCurrentDSO())
continue;
if (Optional<std::string> S = demangle(B->getName()))
(*DemangledSyms)[*S].push_back(B);
else
(*DemangledSyms)[B->getName()].push_back(B);
}
}
return *DemangledSyms;
}
std::vector<SymbolBody *> SymbolTable::findByVersion(SymbolVersion Ver) {
if (Ver.IsExternCpp)
return getDemangledSyms().lookup(Ver.Name);
if (SymbolBody *B = find(Ver.Name))
if (B->isInCurrentDSO())
return {B};
return {};
}
std::vector<SymbolBody *> SymbolTable::findAllByVersion(SymbolVersion Ver) {
std::vector<SymbolBody *> Res;
StringMatcher M(Ver.Name);
if (Ver.IsExternCpp) {
for (auto &P : getDemangledSyms())
if (M.match(P.first()))
Res.insert(Res.end(), P.second.begin(), P.second.end());
return Res;
}
for (Symbol *Sym : SymVector) {
SymbolBody *B = Sym->body();
if (B->isInCurrentDSO() && M.match(B->getName()))
Res.push_back(B);
}
return Res;
}
// If there's only one anonymous version definition in a version
// script file, the script does not actually define any symbol version,
// but just specifies symbols visibilities.
void SymbolTable::handleAnonymousVersion() {
for (SymbolVersion &Ver : Config->VersionScriptGlobals)
assignExactVersion(Ver, VER_NDX_GLOBAL, "global");
for (SymbolVersion &Ver : Config->VersionScriptGlobals)
assignWildcardVersion(Ver, VER_NDX_GLOBAL);
for (SymbolVersion &Ver : Config->VersionScriptLocals)
assignExactVersion(Ver, VER_NDX_LOCAL, "local");
for (SymbolVersion &Ver : Config->VersionScriptLocals)
assignWildcardVersion(Ver, VER_NDX_LOCAL);
}
// Handles -dynamic-list.
void SymbolTable::handleDynamicList() {
for (SymbolVersion &Ver : Config->DynamicList) {
std::vector<SymbolBody *> Syms;
if (Ver.HasWildcard)
Syms = findByVersion(Ver);
else
Syms = findAllByVersion(Ver);
for (SymbolBody *B : Syms) {
if (!Config->Shared)
B->symbol()->ExportDynamic = true;
else if (B->symbol()->includeInDynsym())
B->IsPreemptible = true;
}
}
}
// Set symbol versions to symbols. This function handles patterns
// containing no wildcard characters.
void SymbolTable::assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
StringRef VersionName) {
if (Ver.HasWildcard)
return;
// Get a list of symbols which we need to assign the version to.
std::vector<SymbolBody *> Syms = findByVersion(Ver);
if (Syms.empty()) {
if (Config->NoUndefinedVersion)
error("version script assignment of '" + VersionName + "' to symbol '" +
Ver.Name + "' failed: symbol not defined");
return;
}
// Assign the version.
for (SymbolBody *B : Syms) {
// Skip symbols containing version info because symbol versions
// specified by symbol names take precedence over version scripts.
// See parseSymbolVersion().
if (B->getName().contains('@'))
continue;
Symbol *Sym = B->symbol();
if (Sym->InVersionScript)
warn("duplicate symbol '" + Ver.Name + "' in version script");
Sym->VersionId = VersionId;
Sym->InVersionScript = true;
}
}
void SymbolTable::assignWildcardVersion(SymbolVersion Ver, uint16_t VersionId) {
if (!Ver.HasWildcard)
return;
// Exact matching takes precendence over fuzzy matching,
// so we set a version to a symbol only if no version has been assigned
// to the symbol. This behavior is compatible with GNU.
for (SymbolBody *B : findAllByVersion(Ver))
if (B->symbol()->VersionId == Config->DefaultSymbolVersion)
B->symbol()->VersionId = VersionId;
}
// This function processes version scripts by updating VersionId
// member of symbols.
void SymbolTable::scanVersionScript() {
// Handle edge cases first.
handleAnonymousVersion();
handleDynamicList();
// Now we have version definitions, so we need to set version ids to symbols.
// Each version definition has a glob pattern, and all symbols that match
// with the pattern get that version.
// First, we assign versions to exact matching symbols,
// i.e. version definitions not containing any glob meta-characters.
for (VersionDefinition &V : Config->VersionDefinitions)
for (SymbolVersion &Ver : V.Globals)
assignExactVersion(Ver, V.Id, V.Name);
// Next, we assign versions to fuzzy matching symbols,
// i.e. version definitions containing glob meta-characters.
// Note that because the last match takes precedence over previous matches,
// we iterate over the definitions in the reverse order.
for (VersionDefinition &V : llvm::reverse(Config->VersionDefinitions))
for (SymbolVersion &Ver : V.Globals)
assignWildcardVersion(Ver, V.Id);
// Symbol themselves might know their versions because symbols
// can contain versions in the form of <name>@<version>.
// Let them parse and update their names to exclude version suffix.
for (Symbol *Sym : SymVector)
Sym->body()->parseSymbolVersion();
}
template void SymbolTable::addSymbolWrap<ELF32LE>(StringRef);
template void SymbolTable::addSymbolWrap<ELF32BE>(StringRef);
template void SymbolTable::addSymbolWrap<ELF64LE>(StringRef);
template void SymbolTable::addSymbolWrap<ELF64BE>(StringRef);
template Symbol *SymbolTable::addUndefined<ELF32LE>(StringRef);
template Symbol *SymbolTable::addUndefined<ELF32BE>(StringRef);
template Symbol *SymbolTable::addUndefined<ELF64LE>(StringRef);
template Symbol *SymbolTable::addUndefined<ELF64BE>(StringRef);
template Symbol *SymbolTable::addUndefined<ELF32LE>(StringRef, bool, uint8_t,
uint8_t, uint8_t, bool,
InputFile *);
template Symbol *SymbolTable::addUndefined<ELF32BE>(StringRef, bool, uint8_t,
uint8_t, uint8_t, bool,
InputFile *);
template Symbol *SymbolTable::addUndefined<ELF64LE>(StringRef, bool, uint8_t,
uint8_t, uint8_t, bool,
InputFile *);
template Symbol *SymbolTable::addUndefined<ELF64BE>(StringRef, bool, uint8_t,
uint8_t, uint8_t, bool,
InputFile *);
template void SymbolTable::addSymbolAlias<ELF32LE>(StringRef, StringRef);
template void SymbolTable::addSymbolAlias<ELF32BE>(StringRef, StringRef);
template void SymbolTable::addSymbolAlias<ELF64LE>(StringRef, StringRef);
template void SymbolTable::addSymbolAlias<ELF64BE>(StringRef, StringRef);
template void SymbolTable::addCombinedLTOObject<ELF32LE>();
template void SymbolTable::addCombinedLTOObject<ELF32BE>();
template void SymbolTable::addCombinedLTOObject<ELF64LE>();
template void SymbolTable::addCombinedLTOObject<ELF64BE>();
template Symbol *SymbolTable::addRegular<ELF32LE>(StringRef, uint8_t, uint8_t,
uint64_t, uint64_t, uint8_t,
SectionBase *, InputFile *);
template Symbol *SymbolTable::addRegular<ELF32BE>(StringRef, uint8_t, uint8_t,
uint64_t, uint64_t, uint8_t,
SectionBase *, InputFile *);
template Symbol *SymbolTable::addRegular<ELF64LE>(StringRef, uint8_t, uint8_t,
uint64_t, uint64_t, uint8_t,
SectionBase *, InputFile *);
template Symbol *SymbolTable::addRegular<ELF64BE>(StringRef, uint8_t, uint8_t,
uint64_t, uint64_t, uint8_t,
SectionBase *, InputFile *);
template DefinedRegular *SymbolTable::addAbsolute<ELF32LE>(StringRef, uint8_t,
uint8_t);
template DefinedRegular *SymbolTable::addAbsolute<ELF32BE>(StringRef, uint8_t,
uint8_t);
template DefinedRegular *SymbolTable::addAbsolute<ELF64LE>(StringRef, uint8_t,
uint8_t);
template DefinedRegular *SymbolTable::addAbsolute<ELF64BE>(StringRef, uint8_t,
uint8_t);
template Symbol *
SymbolTable::addLazyArchive<ELF32LE>(StringRef, ArchiveFile *,
const object::Archive::Symbol);
template Symbol *
SymbolTable::addLazyArchive<ELF32BE>(StringRef, ArchiveFile *,
const object::Archive::Symbol);
template Symbol *
SymbolTable::addLazyArchive<ELF64LE>(StringRef, ArchiveFile *,
const object::Archive::Symbol);
template Symbol *
SymbolTable::addLazyArchive<ELF64BE>(StringRef, ArchiveFile *,
const object::Archive::Symbol);
template void SymbolTable::addLazyObject<ELF32LE>(StringRef, LazyObjFile &);
template void SymbolTable::addLazyObject<ELF32BE>(StringRef, LazyObjFile &);
template void SymbolTable::addLazyObject<ELF64LE>(StringRef, LazyObjFile &);
template void SymbolTable::addLazyObject<ELF64BE>(StringRef, LazyObjFile &);
template void SymbolTable::addShared<ELF32LE>(StringRef, SharedFile<ELF32LE> *,
const typename ELF32LE::Sym &,
const typename ELF32LE::Verdef *);
template void SymbolTable::addShared<ELF32BE>(StringRef, SharedFile<ELF32BE> *,
const typename ELF32BE::Sym &,
const typename ELF32BE::Verdef *);
template void SymbolTable::addShared<ELF64LE>(StringRef, SharedFile<ELF64LE> *,
const typename ELF64LE::Sym &,
const typename ELF64LE::Verdef *);
template void SymbolTable::addShared<ELF64BE>(StringRef, SharedFile<ELF64BE> *,
const typename ELF64BE::Sym &,
const typename ELF64BE::Verdef *);
template void SymbolTable::fetchIfLazy<ELF32LE>(StringRef);
template void SymbolTable::fetchIfLazy<ELF32BE>(StringRef);
template void SymbolTable::fetchIfLazy<ELF64LE>(StringRef);
template void SymbolTable::fetchIfLazy<ELF64BE>(StringRef);
template void SymbolTable::scanShlibUndefined<ELF32LE>();
template void SymbolTable::scanShlibUndefined<ELF32BE>();
template void SymbolTable::scanShlibUndefined<ELF64LE>();
template void SymbolTable::scanShlibUndefined<ELF64BE>();
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