blob: 7c708ce4ed67d5d19892db77a98ccd87ca431c0b [file] [log] [blame]
//===- OutputSections.cpp -------------------------------------------------===//
// The LLVM Linker
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "OutputSections.h"
#include "Config.h"
#include "EhFrame.h"
#include "LinkerScript.h"
#include "Memory.h"
#include "Strings.h"
#include "SymbolTable.h"
#include "SyntheticSections.h"
#include "Target.h"
#include "Threads.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/SHA1.h"
using namespace llvm;
using namespace llvm::dwarf;
using namespace llvm::object;
using namespace llvm::support::endian;
using namespace llvm::ELF;
using namespace lld;
using namespace lld::elf;
OutputSectionBase::OutputSectionBase(StringRef Name, uint32_t Type,
uint64_t Flags)
: Name(Name) {
this->Type = Type;
this->Flags = Flags;
this->Addralign = 1;
uint32_t OutputSectionBase::getPhdrFlags() const {
uint32_t Ret = PF_R;
if (Flags & SHF_WRITE)
Ret |= PF_W;
if (Flags & SHF_EXECINSTR)
Ret |= PF_X;
return Ret;
template <class ELFT>
void OutputSectionBase::writeHeaderTo(typename ELFT::Shdr *Shdr) {
Shdr->sh_entsize = Entsize;
Shdr->sh_addralign = Addralign;
Shdr->sh_type = Type;
Shdr->sh_offset = Offset;
Shdr->sh_flags = Flags;
Shdr->sh_info = Info;
Shdr->sh_link = Link;
Shdr->sh_addr = Addr;
Shdr->sh_size = Size;
Shdr->sh_name = ShName;
template <class ELFT> static uint64_t getEntsize(uint32_t Type) {
switch (Type) {
case SHT_RELA:
return sizeof(typename ELFT::Rela);
case SHT_REL:
return sizeof(typename ELFT::Rel);
return sizeof(Elf_Mips_RegInfo<ELFT>);
return sizeof(Elf_Mips_Options<ELFT>) + sizeof(Elf_Mips_RegInfo<ELFT>);
return sizeof(Elf_Mips_ABIFlags<ELFT>);
return 0;
template <class ELFT>
OutputSection<ELFT>::OutputSection(StringRef Name, uint32_t Type, uintX_t Flags)
: OutputSectionBase(Name, Type, Flags) {
this->Entsize = getEntsize<ELFT>(Type);
template <typename ELFT>
static bool compareByFilePosition(InputSection<ELFT> *A,
InputSection<ELFT> *B) {
// Synthetic doesn't have link order dependecy, stable_sort will keep it last
if (A->kind() == InputSectionData::Synthetic ||
B->kind() == InputSectionData::Synthetic)
return false;
auto *LA = cast<InputSection<ELFT>>(A->getLinkOrderDep());
auto *LB = cast<InputSection<ELFT>>(B->getLinkOrderDep());
OutputSectionBase *AOut = LA->OutSec;
OutputSectionBase *BOut = LB->OutSec;
if (AOut != BOut)
return AOut->SectionIndex < BOut->SectionIndex;
return LA->OutSecOff < LB->OutSecOff;
template <class ELFT> void OutputSection<ELFT>::finalize() {
if ((this->Flags & SHF_LINK_ORDER) && !this->Sections.empty()) {
std::sort(Sections.begin(), Sections.end(), compareByFilePosition<ELFT>);
Size = 0;
// We must preserve the link order dependency of sections with the
// SHF_LINK_ORDER flag. The dependency is indicated by the sh_link field. We
// need to translate the InputSection sh_link to the OutputSection sh_link,
// all InputSections in the OutputSection have the same dependency.
if (auto *D = this->Sections.front()->getLinkOrderDep())
this->Link = D->OutSec->SectionIndex;
uint32_t Type = this->Type;
if (!Config->Relocatable || (Type != SHT_RELA && Type != SHT_REL))
this->Link = In<ELFT>::SymTab->OutSec->SectionIndex;
// sh_info for SHT_REL[A] sections should contain the section header index of
// the section to which the relocation applies.
InputSectionBase<ELFT> *S = Sections[0]->getRelocatedSection();
this->Info = S->OutSec->SectionIndex;
template <class ELFT>
void OutputSection<ELFT>::addSection(InputSectionData *C) {
auto *S = cast<InputSection<ELFT>>(C);
S->OutSec = this;
// Keep sh_entsize value of the input section to be able to perform merging
// later during a final linking using the generated relocatable object.
if (Config->Relocatable && (S->Flags & SHF_MERGE))
this->Entsize = S->Entsize;
// This function is called after we sort input sections
// and scan relocations to setup sections' offsets.
template <class ELFT> void OutputSection<ELFT>::assignOffsets() {
uintX_t Off = this->Size;
for (InputSection<ELFT> *S : Sections) {
Off = alignTo(Off, S->Alignment);
S->OutSecOff = Off;
Off += S->getSize();
this->Size = Off;
template <class ELFT>
void OutputSection<ELFT>::sort(
std::function<int(InputSection<ELFT> *S)> Order) {
typedef std::pair<unsigned, InputSection<ELFT> *> Pair;
auto Comp = [](const Pair &A, const Pair &B) { return A.first < B.first; };
std::vector<Pair> V;
for (InputSection<ELFT> *S : Sections)
V.push_back({Order(S), S});
std::stable_sort(V.begin(), V.end(), Comp);
for (Pair &P : V)
// Sorts input sections by section name suffixes, so that .foo.N comes
// before .foo.M if N < M. Used to sort .{init,fini}_array.N sections.
// We want to keep the original order if the priorities are the same
// because the compiler keeps the original initialization order in a
// translation unit and we need to respect that.
// For more detail, read the section of the GCC's manual about init_priority.
template <class ELFT> void OutputSection<ELFT>::sortInitFini() {
// Sort sections by priority.
sort([](InputSection<ELFT> *S) { return getPriority(S->Name); });
// Returns true if S matches /Filename.?\.o$/.
static bool isCrtBeginEnd(StringRef S, StringRef Filename) {
if (!S.endswith(".o"))
return false;
S = S.drop_back(2);
if (S.endswith(Filename))
return true;
return !S.empty() && S.drop_back().endswith(Filename);
static bool isCrtbegin(StringRef S) { return isCrtBeginEnd(S, "crtbegin"); }
static bool isCrtend(StringRef S) { return isCrtBeginEnd(S, "crtend"); }
// .ctors and .dtors are sorted by this priority from highest to lowest.
// 1. The section was contained in crtbegin (crtbegin contains
// some sentinel value in its .ctors and .dtors so that the runtime
// can find the beginning of the sections.)
// 2. The section has an optional priority value in the form of ".ctors.N"
// or ".dtors.N" where N is a number. Unlike .{init,fini}_array,
// they are compared as string rather than number.
// 3. The section is just ".ctors" or ".dtors".
// 4. The section was contained in crtend, which contains an end marker.
// In an ideal world, we don't need this function because .init_array and
// .ctors are duplicate features (and .init_array is newer.) However, there
// are too many real-world use cases of .ctors, so we had no choice to
// support that with this rather ad-hoc semantics.
template <class ELFT>
static bool compCtors(const InputSection<ELFT> *A,
const InputSection<ELFT> *B) {
bool BeginA = isCrtbegin(A->getFile()->getName());
bool BeginB = isCrtbegin(B->getFile()->getName());
if (BeginA != BeginB)
return BeginA;
bool EndA = isCrtend(A->getFile()->getName());
bool EndB = isCrtend(B->getFile()->getName());
if (EndA != EndB)
return EndB;
StringRef X = A->Name;
StringRef Y = B->Name;
assert(X.startswith(".ctors") || X.startswith(".dtors"));
assert(Y.startswith(".ctors") || Y.startswith(".dtors"));
X = X.substr(6);
Y = Y.substr(6);
if (X.empty() && Y.empty())
return false;
return X < Y;
// Sorts input sections by the special rules for .ctors and .dtors.
// Unfortunately, the rules are different from the one for .{init,fini}_array.
// Read the comment above.
template <class ELFT> void OutputSection<ELFT>::sortCtorsDtors() {
std::stable_sort(Sections.begin(), Sections.end(), compCtors<ELFT>);
// Fill [Buf, Buf + Size) with Filler. Filler is written in big
// endian order. This is used for linker script "=fillexp" command.
void fill(uint8_t *Buf, size_t Size, uint32_t Filler) {
uint8_t V[4];
write32be(V, Filler);
size_t I = 0;
for (; I + 4 < Size; I += 4)
memcpy(Buf + I, V, 4);
memcpy(Buf + I, V, Size - I);
template <class ELFT> void OutputSection<ELFT>::writeTo(uint8_t *Buf) {
Loc = Buf;
if (uint32_t Filler = Script<ELFT>::X->getFiller(this->Name))
fill(Buf, this->Size, Filler);
auto Fn = [=](InputSection<ELFT> *IS) { IS->writeTo(Buf); };
forEach(Sections.begin(), Sections.end(), Fn);
// Linker scripts may have BYTE()-family commands with which you
// can write arbitrary bytes to the output. Process them if any.
Script<ELFT>::X->writeDataBytes(this->Name, Buf);
template <class ELFT>
: OutputSectionBase(".eh_frame", SHT_PROGBITS, SHF_ALLOC) {}
// Search for an existing CIE record or create a new one.
// CIE records from input object files are uniquified by their contents
// and where their relocations point to.
template <class ELFT>
template <class RelTy>
CieRecord *EhOutputSection<ELFT>::addCie(EhSectionPiece &Piece,
ArrayRef<RelTy> Rels) {
auto *Sec = cast<EhInputSection<ELFT>>(Piece.ID);
const endianness E = ELFT::TargetEndianness;
if (read32<E>( + 4) != 0)
fatal(toString(Sec) + ": CIE expected at beginning of .eh_frame");
SymbolBody *Personality = nullptr;
unsigned FirstRelI = Piece.FirstRelocation;
if (FirstRelI != (unsigned)-1)
Personality = &Sec->getFile()->getRelocTargetSym(Rels[FirstRelI]);
// Search for an existing CIE by CIE contents/relocation target pair.
CieRecord *Cie = &CieMap[{, Personality}];
// If not found, create a new one.
if (Cie->Piece == nullptr) {
Cie->Piece = &Piece;
return Cie;
// There is one FDE per function. Returns true if a given FDE
// points to a live function.
template <class ELFT>
template <class RelTy>
bool EhOutputSection<ELFT>::isFdeLive(EhSectionPiece &Piece,
ArrayRef<RelTy> Rels) {
auto *Sec = cast<EhInputSection<ELFT>>(Piece.ID);
unsigned FirstRelI = Piece.FirstRelocation;
if (FirstRelI == (unsigned)-1)
fatal(toString(Sec) + ": FDE doesn't reference another section");
const RelTy &Rel = Rels[FirstRelI];
SymbolBody &B = Sec->getFile()->getRelocTargetSym(Rel);
auto *D = dyn_cast<DefinedRegular<ELFT>>(&B);
if (!D || !D->Section)
return false;
InputSectionBase<ELFT> *Target = D->Section->Repl;
return Target && Target->Live;
// .eh_frame is a sequence of CIE or FDE records. In general, there
// is one CIE record per input object file which is followed by
// a list of FDEs. This function searches an existing CIE or create a new
// one and associates FDEs to the CIE.
template <class ELFT>
template <class RelTy>
void EhOutputSection<ELFT>::addSectionAux(EhInputSection<ELFT> *Sec,
ArrayRef<RelTy> Rels) {
const endianness E = ELFT::TargetEndianness;
DenseMap<size_t, CieRecord *> OffsetToCie;
for (EhSectionPiece &Piece : Sec->Pieces) {
// The empty record is the end marker.
if (Piece.size() == 4)
size_t Offset = Piece.InputOff;
uint32_t ID = read32<E>( + 4);
if (ID == 0) {
OffsetToCie[Offset] = addCie(Piece, Rels);
uint32_t CieOffset = Offset + 4 - ID;
CieRecord *Cie = OffsetToCie[CieOffset];
if (!Cie)
fatal(toString(Sec) + ": invalid CIE reference");
if (!isFdeLive(Piece, Rels))
template <class ELFT>
void EhOutputSection<ELFT>::addSection(InputSectionData *C) {
auto *Sec = cast<EhInputSection<ELFT>>(C);
Sec->OutSec = this;
// .eh_frame is a sequence of CIE or FDE records. This function
// splits it into pieces so that we can call
// SplitInputSection::getSectionPiece on the section.
if (Sec->Pieces.empty())
if (Sec->NumRelocations) {
if (Sec->AreRelocsRela)
addSectionAux(Sec, Sec->relas());
addSectionAux(Sec, Sec->rels());
addSectionAux(Sec, makeArrayRef<Elf_Rela>(nullptr, nullptr));
template <class ELFT>
static void writeCieFde(uint8_t *Buf, ArrayRef<uint8_t> D) {
memcpy(Buf,, D.size());
// Fix the size field. -4 since size does not include the size field itself.
const endianness E = ELFT::TargetEndianness;
write32<E>(Buf, alignTo(D.size(), sizeof(typename ELFT::uint)) - 4);
template <class ELFT> void EhOutputSection<ELFT>::finalize() {
if (this->Size)
return; // Already finalized.
size_t Off = 0;
for (CieRecord *Cie : Cies) {
Cie->Piece->OutputOff = Off;
Off += alignTo(Cie->Piece->size(), sizeof(uintX_t));
for (EhSectionPiece *Fde : Cie->FdePieces) {
Fde->OutputOff = Off;
Off += alignTo(Fde->size(), sizeof(uintX_t));
this->Size = Off;
template <class ELFT> static uint64_t readFdeAddr(uint8_t *Buf, int Size) {
const endianness E = ELFT::TargetEndianness;
switch (Size) {
case DW_EH_PE_udata2:
return read16<E>(Buf);
case DW_EH_PE_udata4:
return read32<E>(Buf);
case DW_EH_PE_udata8:
return read64<E>(Buf);
case DW_EH_PE_absptr:
if (ELFT::Is64Bits)
return read64<E>(Buf);
return read32<E>(Buf);
fatal("unknown FDE size encoding");
// Returns the VA to which a given FDE (on a mmap'ed buffer) is applied to.
// We need it to create .eh_frame_hdr section.
template <class ELFT>
typename ELFT::uint EhOutputSection<ELFT>::getFdePc(uint8_t *Buf, size_t FdeOff,
uint8_t Enc) {
// The starting address to which this FDE applies is
// stored at FDE + 8 byte.
size_t Off = FdeOff + 8;
uint64_t Addr = readFdeAddr<ELFT>(Buf + Off, Enc & 0x7);
if ((Enc & 0x70) == DW_EH_PE_absptr)
return Addr;
if ((Enc & 0x70) == DW_EH_PE_pcrel)
return Addr + this->Addr + Off;
fatal("unknown FDE size relative encoding");
template <class ELFT> void EhOutputSection<ELFT>::writeTo(uint8_t *Buf) {
const endianness E = ELFT::TargetEndianness;
for (CieRecord *Cie : Cies) {
size_t CieOffset = Cie->Piece->OutputOff;
writeCieFde<ELFT>(Buf + CieOffset, Cie->Piece->data());
for (EhSectionPiece *Fde : Cie->FdePieces) {
size_t Off = Fde->OutputOff;
writeCieFde<ELFT>(Buf + Off, Fde->data());
// FDE's second word should have the offset to an associated CIE.
// Write it.
write32<E>(Buf + Off + 4, Off + 4 - CieOffset);
for (EhInputSection<ELFT> *S : Sections)
S->relocate(Buf, nullptr);
// Construct .eh_frame_hdr. .eh_frame_hdr is a binary search table
// to get a FDE from an address to which FDE is applied. So here
// we obtain two addresses and pass them to EhFrameHdr object.
if (In<ELFT>::EhFrameHdr) {
for (CieRecord *Cie : Cies) {
uint8_t Enc = getFdeEncoding<ELFT>(Cie->Piece);
for (SectionPiece *Fde : Cie->FdePieces) {
uintX_t Pc = getFdePc(Buf, Fde->OutputOff, Enc);
uintX_t FdeVA = this->Addr + Fde->OutputOff;
In<ELFT>::EhFrameHdr->addFde(Pc, FdeVA);
template <class ELFT>
MergeOutputSection<ELFT>::MergeOutputSection(StringRef Name, uint32_t Type,
uintX_t Flags, uintX_t Alignment)
: OutputSectionBase(Name, Type, Flags),
Builder(StringTableBuilder::RAW, Alignment) {}
template <class ELFT> void MergeOutputSection<ELFT>::writeTo(uint8_t *Buf) {
template <class ELFT>
void MergeOutputSection<ELFT>::addSection(InputSectionData *C) {
auto *Sec = cast<MergeInputSection<ELFT>>(C);
Sec->OutSec = this;
this->Entsize = Sec->Entsize;
template <class ELFT> bool MergeOutputSection<ELFT>::shouldTailMerge() const {
return (this->Flags & SHF_STRINGS) && Config->Optimize >= 2;
template <class ELFT> void MergeOutputSection<ELFT>::finalizeTailMerge() {
// Add all string pieces to the string table builder to create section
// contents.
for (MergeInputSection<ELFT> *Sec : Sections)
for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
if (Sec->Pieces[I].Live)
// Fix the string table content. After this, the contents will never change.
this->Size = Builder.getSize();
// finalize() fixed tail-optimized strings, so we can now get
// offsets of strings. Get an offset for each string and save it
// to a corresponding StringPiece for easy access.
for (MergeInputSection<ELFT> *Sec : Sections)
for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
if (Sec->Pieces[I].Live)
Sec->Pieces[I].OutputOff = Builder.getOffset(Sec->getData(I));
template <class ELFT> void MergeOutputSection<ELFT>::finalizeNoTailMerge() {
// Add all string pieces to the string table builder to create section
// contents. Because we are not tail-optimizing, offsets of strings are
// fixed when they are added to the builder (string table builder contains
// a hash table from strings to offsets).
for (MergeInputSection<ELFT> *Sec : Sections)
for (size_t I = 0, E = Sec->Pieces.size(); I != E; ++I)
if (Sec->Pieces[I].Live)
Sec->Pieces[I].OutputOff = Builder.add(Sec->getData(I));
this->Size = Builder.getSize();
template <class ELFT> void MergeOutputSection<ELFT>::finalize() {
if (shouldTailMerge())
template <class ELFT>
static typename ELFT::uint getOutFlags(InputSectionBase<ELFT> *S) {
return S->Flags & ~SHF_GROUP & ~SHF_COMPRESSED;
namespace llvm {
template <> struct DenseMapInfo<lld::elf::SectionKey> {
static lld::elf::SectionKey getEmptyKey();
static lld::elf::SectionKey getTombstoneKey();
static unsigned getHashValue(const lld::elf::SectionKey &Val);
static bool isEqual(const lld::elf::SectionKey &LHS,
const lld::elf::SectionKey &RHS);
template <class ELFT>
static SectionKey createKey(InputSectionBase<ELFT> *C, StringRef OutsecName) {
// The ELF spec just says
// ----------------------------------------------------------------
// In the first phase, input sections that match in name, type and
// attribute flags should be concatenated into single sections.
// ----------------------------------------------------------------
// However, it is clear that at least some flags have to be ignored for
// section merging. At the very least SHF_GROUP and SHF_COMPRESSED have to be
// ignored. We should not have two output .text sections just because one was
// in a group and another was not for example.
// It also seems that that wording was a late addition and didn't get the
// necessary scrutiny.
// Merging sections with different flags is expected by some users. One
// reason is that if one file has
// int *const bar __attribute__((section(".foo"))) = (int *)0;
// gcc with -fPIC will produce a read only .foo section. But if another
// file has
// int zed;
// int *const bar __attribute__((section(".foo"))) = (int *)&zed;
// gcc with -fPIC will produce a read write section.
// Last but not least, when using linker script the merge rules are forced by
// the script. Unfortunately, linker scripts are name based. This means that
// expressions like *(.foo*) can refer to multiple input sections with
// different flags. We cannot put them in different output sections or we
// would produce wrong results for
// start = .; *(.foo.*) end = .; *(.bar)
// and a mapping of .foo1 and .bar1 to one section and .foo2 and .bar2 to
// another. The problem is that there is no way to layout those output
// sections such that the .foo sections are the only thing between the start
// and end symbols.
// Given the above issues, we instead merge sections by name and error on
// incompatible types and flags.
// The exception being SHF_MERGE, where we create different output sections
// for each alignment. This makes each output section simple. In case of
// relocatable object generation we do not try to perform merging and treat
// SHF_MERGE sections as regular ones, but also create different output
// sections for them to allow merging at final linking stage.
// Fortunately, creating symbols in the middle of a merge section is not
// supported by bfd or gold, so the SHF_MERGE exception should not cause
// problems with most linker scripts.
typedef typename ELFT::uint uintX_t;
uintX_t Flags = C->Flags & (SHF_MERGE | SHF_STRINGS);
uintX_t Alignment = 0;
if (isa<MergeInputSection<ELFT>>(C) ||
(Config->Relocatable && (C->Flags & SHF_MERGE)))
Alignment = std::max<uintX_t>(C->Alignment, C->Entsize);
return SectionKey{OutsecName, Flags, Alignment};
template <class ELFT> OutputSectionFactory<ELFT>::OutputSectionFactory() {}
template <class ELFT> OutputSectionFactory<ELFT>::~OutputSectionFactory() {}
template <class ELFT>
std::pair<OutputSectionBase *, bool>
OutputSectionFactory<ELFT>::create(InputSectionBase<ELFT> *C,
StringRef OutsecName) {
SectionKey Key = createKey(C, OutsecName);
return create(Key, C);
static uint64_t getIncompatibleFlags(uint64_t Flags) {
return Flags & (SHF_ALLOC | SHF_TLS);
template <class ELFT>
std::pair<OutputSectionBase *, bool>
OutputSectionFactory<ELFT>::create(const SectionKey &Key,
InputSectionBase<ELFT> *C) {
uintX_t Flags = getOutFlags(C);
OutputSectionBase *&Sec = Map[Key];
if (Sec) {
if (getIncompatibleFlags(Sec->Flags) != getIncompatibleFlags(C->Flags))
error("Section has flags incompatible with others with the same name " +
// Convert notbits to progbits if they are mixed. This happens is some
// linker scripts.
if (Sec->Type == SHT_NOBITS && C->Type == SHT_PROGBITS)
if (Sec->Type != C->Type &&
!(Sec->Type == SHT_PROGBITS && C->Type == SHT_NOBITS))
error("Section has different type from others with the same name " +
Sec->Flags |= Flags;
return {Sec, false};
uint32_t Type = C->Type;
switch (C->kind()) {
case InputSectionBase<ELFT>::Regular:
case InputSectionBase<ELFT>::Synthetic:
Sec = make<OutputSection<ELFT>>(Key.Name, Type, Flags);
case InputSectionBase<ELFT>::EHFrame:
return {Out<ELFT>::EhFrame, false};
case InputSectionBase<ELFT>::Merge:
Sec = make<MergeOutputSection<ELFT>>(Key.Name, Type, Flags, Key.Alignment);
return {Sec, true};
SectionKey DenseMapInfo<SectionKey>::getEmptyKey() {
return SectionKey{DenseMapInfo<StringRef>::getEmptyKey(), 0, 0};
SectionKey DenseMapInfo<SectionKey>::getTombstoneKey() {
return SectionKey{DenseMapInfo<StringRef>::getTombstoneKey(), 0, 0};
unsigned DenseMapInfo<SectionKey>::getHashValue(const SectionKey &Val) {
return hash_combine(Val.Name, Val.Flags, Val.Alignment);
bool DenseMapInfo<SectionKey>::isEqual(const SectionKey &LHS,
const SectionKey &RHS) {
return DenseMapInfo<StringRef>::isEqual(LHS.Name, RHS.Name) &&
LHS.Flags == RHS.Flags && LHS.Alignment == RHS.Alignment;
namespace lld {
namespace elf {
template void OutputSectionBase::writeHeaderTo<ELF32LE>(ELF32LE::Shdr *Shdr);
template void OutputSectionBase::writeHeaderTo<ELF32BE>(ELF32BE::Shdr *Shdr);
template void OutputSectionBase::writeHeaderTo<ELF64LE>(ELF64LE::Shdr *Shdr);
template void OutputSectionBase::writeHeaderTo<ELF64BE>(ELF64BE::Shdr *Shdr);
template class OutputSection<ELF32LE>;
template class OutputSection<ELF32BE>;
template class OutputSection<ELF64LE>;
template class OutputSection<ELF64BE>;
template class EhOutputSection<ELF32LE>;
template class EhOutputSection<ELF32BE>;
template class EhOutputSection<ELF64LE>;
template class EhOutputSection<ELF64BE>;
template class MergeOutputSection<ELF32LE>;
template class MergeOutputSection<ELF32BE>;
template class MergeOutputSection<ELF64LE>;
template class MergeOutputSection<ELF64BE>;
template class OutputSectionFactory<ELF32LE>;
template class OutputSectionFactory<ELF32BE>;
template class OutputSectionFactory<ELF64LE>;
template class OutputSectionFactory<ELF64BE>;