static typename ELFT::uint getSymVA(const SymbolBody &Body,
typename ELFT::uint &Addend) {
typedef typename ELFT::uint uintX_t;
switch (Body.kind()) {
case SymbolBody::DefinedSyntheticKind: {
auto &D = cast<DefinedSynthetic<ELFT>>(Body);
const OutputSectionBase<ELFT> *Sec = D.Section;
if (!Sec)
return D.Value;
if (D.Value == DefinedSynthetic<ELFT>::SectionEnd)
return Sec->getVA() + Sec->getSize();
return Sec->getVA() + D.Value;
}
case SymbolBody::DefinedRegularKind: {
auto &D = cast<DefinedRegular<ELFT>>(Body);
InputSectionBase<ELFT> *SC = D.Section;
// According to the ELF spec reference to a local symbol from outside
// the group are not allowed. Unfortunately .eh_frame breaks that rule
// and must be treated specially. For now we just replace the symbol with
// 0.
if (SC == &InputSection<ELFT>::Discarded)
return 0;
// This is an absolute symbol.
if (!SC)
return D.Value;
uintX_t Offset = D.Value;
if (D.isSection()) {
Offset += Addend;
Addend = 0;
}
uintX_t VA = SC->OutSec->getVA() + SC->getOffset(Offset);
if (D.isTls())
return VA - Out<ELFT>::TlsPhdr->p_vaddr;
return VA;
}
case SymbolBody::DefinedCommonKind:
return Out<ELFT>::Bss->getVA() + cast<DefinedCommon>(Body).OffsetInBss;
case SymbolBody::SharedKind: {
auto &SS = cast<SharedSymbol<ELFT>>(Body);
if (!SS.NeedsCopyOrPltAddr)
return 0;
if (SS.isFunc())
return Body.getPltVA<ELFT>();
return Out<ELFT>::Bss->getVA() + SS.OffsetInBss;
}
case SymbolBody::UndefinedKind:
return 0;
case SymbolBody::LazyArchiveKind:
case SymbolBody::LazyObjectKind:
assert(Body.symbol()->IsUsedInRegularObj && "lazy symbol reached writer");
return 0;
case SymbolBody::DefinedBitcodeKind:
llvm_unreachable("should have been replaced");
}
llvm_unreachable("invalid symbol kind");
}
void InputSection::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) {
InputSectionBase *Sec = getRelocatedSection();
for (const RelTy &Rel : Rels) {
RelType Type = Rel.getType(Config->IsMips64EL);
Symbol &Sym = getFile<ELFT>()->getRelocTargetSym(Rel);
auto *P = reinterpret_cast<typename ELFT::Rela *>(Buf);
Buf += sizeof(RelTy);
if (Config->IsRela)
P->r_addend = getAddend<ELFT>(Rel);
// Output section VA is zero for -r, so r_offset is an offset within the
// section, but for --emit-relocs it is an virtual address.
P->r_offset = Sec->getOutputSection()->Addr + Sec->getOffset(Rel.r_offset);
P->setSymbolAndType(InX::SymTab->getSymbolIndex(&Sym), Type,
Config->IsMips64EL);
if (Sym.Type == STT_SECTION) {
// We combine multiple section symbols into only one per
// section. This means we have to update the addend. That is
// trivial for Elf_Rela, but for Elf_Rel we have to write to the
// section data. We do that by adding to the Relocation vector.
// .eh_frame is horribly special and can reference discarded sections. To
// avoid having to parse and recreate .eh_frame, we just replace any
// relocation in it pointing to discarded sections with R_*_NONE, which
// hopefully creates a frame that is ignored at runtime.
auto *D = dyn_cast<Defined>(&Sym);
if (!D) {
error("STT_SECTION symbol should be defined");
continue;
}
SectionBase *Section = D->Section;
if (Section == &InputSection::Discarded) {
P->setSymbolAndType(0, 0, false);
continue;
}
if (Config->IsRela) {
P->r_addend =
Sym.getVA(getAddend<ELFT>(Rel)) - Section->getOutputSection()->Addr;
} else if (Config->Relocatable) {
const uint8_t *BufLoc = Sec->Data.begin() + Rel.r_offset;
Sec->Relocations.push_back({R_ABS, Type, Rel.r_offset,
Target->getImplicitAddend(BufLoc, Type),
&Sym});
}
}
}
}
void InputSection<ELFT>::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) {
InputSectionBase<ELFT> *RelocatedSection = getRelocatedSection();
for (const RelTy &Rel : Rels) {
uint32_t Type = Rel.getType(Config->Mips64EL);
SymbolBody &Body = this->File->getRelocTargetSym(Rel);
RelTy *P = reinterpret_cast<RelTy *>(Buf);
Buf += sizeof(RelTy);
P->r_offset = RelocatedSection->getOffset(Rel.r_offset);
P->setSymbolAndType(Body.DynsymIndex, Type, Config->Mips64EL);
}
}
void Writer<ELFT>::scanRelocs(InputSectionBase<ELFT> &S,
const Elf_Shdr &RelSec) {
ELFFile<ELFT> &EObj = S.getFile()->getObj();
if (RelSec.sh_type == SHT_RELA)
scanRelocs(S, EObj.relas(&RelSec));
else
scanRelocs(S, EObj.rels(&RelSec));
}
template <class ELFT> void OutputSection::finalize() {
if (Type == SHT_NOBITS)
for (BaseCommand *Base : SectionCommands)
if (isa<ByteCommand>(Base))
Type = SHT_PROGBITS;
std::vector<InputSection *> V = getInputSections(this);
InputSection *First = V.empty() ? nullptr : V[0];
if (Flags & SHF_LINK_ORDER) {
// 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 = First->getLinkOrderDep())
Link = D->getParent()->SectionIndex;
}
if (Type == SHT_GROUP) {
finalizeShtGroup<ELFT>(this, First);
return;
}
if (!Config->CopyRelocs || (Type != SHT_RELA && Type != SHT_REL))
return;
if (isa<SyntheticSection>(First))
return;
Link = In.SymTab->getParent()->SectionIndex;
// sh_info for SHT_REL[A] sections should contain the section header index of
// the section to which the relocation applies.
InputSectionBase *S = First->getRelocatedSection();
Info = S->getOutputSection()->SectionIndex;
Flags |= SHF_INFO_LINK;
}
void Writer<ELFT>::scanRelocs(
InputSectionBase<ELFT> &C,
iterator_range<const Elf_Rel_Impl<ELFT, isRela> *> Rels) {
typedef Elf_Rel_Impl<ELFT, isRela> RelType;
const ObjectFile<ELFT> &File = *C.getFile();
for (const RelType &RI : Rels) {
uint32_t SymIndex = RI.getSymbol(Config->Mips64EL);
SymbolBody *Body = File.getSymbolBody(SymIndex);
uint32_t Type = RI.getType(Config->Mips64EL);
if (Target->isTlsLocalDynamicReloc(Type)) {
if (Target->isTlsOptimized(Type, nullptr))
continue;
if (Out<ELFT>::LocalModuleTlsIndexOffset == uint32_t(-1)) {
Out<ELFT>::LocalModuleTlsIndexOffset =
Out<ELFT>::Got->addLocalModuleTlsIndex();
Out<ELFT>::RelaDyn->addReloc({&C, &RI});
}
continue;
}
// Set "used" bit for --as-needed.
if (Body && Body->isUndefined() && !Body->isWeak())
if (auto *S = dyn_cast<SharedSymbol<ELFT>>(Body->repl()))
S->File->IsUsed = true;
if (Body)
Body = Body->repl();
if (Body && Body->isTLS() && Target->isTlsGlobalDynamicReloc(Type)) {
if (Target->isTlsOptimized(Type, Body))
continue;
if (Body->isInGot())
continue;
Out<ELFT>::Got->addDynTlsEntry(Body);
Out<ELFT>::RelaDyn->addReloc({&C, &RI});
Out<ELFT>::RelaDyn->addReloc({nullptr, nullptr});
Body->setUsedInDynamicReloc();
continue;
}
if (Body && Body->isTLS() && !Target->isTlsDynReloc(Type))
continue;
bool NeedsGot = false;
bool NeedsPlt = false;
if (Body) {
if (auto *E = dyn_cast<SharedSymbol<ELFT>>(Body)) {
if (E->needsCopy())
continue;
if (Target->relocNeedsCopy(Type, *Body))
E->OffsetInBSS = 0;
}
NeedsPlt = Target->relocNeedsPlt(Type, *Body);
if (NeedsPlt) {
if (Body->isInPlt())
continue;
Out<ELFT>::Plt->addEntry(Body);
}
NeedsGot = Target->relocNeedsGot(Type, *Body);
if (NeedsGot) {
if (NeedsPlt && Target->supportsLazyRelocations()) {
Out<ELFT>::GotPlt->addEntry(Body);
} else {
if (Body->isInGot())
continue;
Out<ELFT>::Got->addEntry(Body);
}
}
}
if (Config->EMachine == EM_MIPS && NeedsGot) {
// MIPS ABI has special rules to process GOT entries
// and doesn't require relocation entries for them.
// See "Global Offset Table" in Chapter 5 in the following document
// for detailed description:
// ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
Body->setUsedInDynamicReloc();
continue;
}
bool CBP = canBePreempted(Body, NeedsGot);
if (!CBP && (!Config->Shared || Target->isRelRelative(Type)))
continue;
if (CBP)
Body->setUsedInDynamicReloc();
if (NeedsPlt && Target->supportsLazyRelocations())
Out<ELFT>::RelaPlt->addReloc({&C, &RI});
else
Out<ELFT>::RelaDyn->addReloc({&C, &RI});
}
}
std::string lld::verboseToString(Symbol *B, uint64_t SymOffset) {
std::string Msg;
if (B->isLocal())
Msg += "local ";
if (B->isWeak())
Msg += "weak ";
if (B->isShared())
Msg += "shared ";
// else if (B->isDefined())
// Msg += "defined ";
if (B->Type == STT_COMMON)
Msg += "common ";
else if (B->Type == STT_TLS)
Msg += "TLS ";
if (B->isSection())
Msg += "section ";
else if (B->isTls())
Msg += "tls ";
else if (B->isFunc())
Msg += "function ";
else if (B->isGnuIFunc())
Msg += "gnu ifunc ";
else if (B->isObject())
Msg += "object ";
else if (B->isFile())
Msg += "file ";
else if (B->isUndefined())
Msg += "<undefined> ";
else
Msg += "<unknown kind> ";
if (B->isInGot())
Msg += "(in GOT) ";
if (B->isInPlt())
Msg += "(in PLT) ";
Defined* DR = dyn_cast<Defined>(B);
InputSectionBase* IS = nullptr;
if (DR && DR->Section) {
SymOffset = DR->isSection() ? SymOffset : DR->Section->getOffset(DR->Value);
IS = dyn_cast<InputSectionBase>(DR->Section);
}
std::string Name = toString(*B);
if (Name.empty()) {
if (DR && DR->Section) {
if (IS) {
Name = IS->getLocation<ELFT>(SymOffset);
} else {
Name = (DR->Section->Name + "+0x" + utohexstr(SymOffset)).str();
}
} else if (OutputSection* OS = B->getOutputSection()) {
Name = (OS->Name + "+(unknown offset)").str();
}
}
if (Name.empty()) {
Name = "<unknown symbol>";
}
Msg += Name;
if (!B->isUndefined()) {
std::string Src = IS ? IS->getSrcMsg(*B, SymOffset) : toString(B->File);
if (IS)
Src += " (" + IS->getObjMsg(SymOffset) + ")";
Msg += "\n>>> defined in " + Src;
}
return Msg;
}
static typename ELFT::uint getSymVA(const SymbolBody &Body,
typename ELFT::uint &Addend) {
typedef typename ELFT::uint uintX_t;
switch (Body.kind()) {
case SymbolBody::DefinedSyntheticKind: {
auto &D = cast<DefinedSynthetic>(Body);
const OutputSectionBase *Sec = D.Section;
if (!Sec)
return D.Value;
if (D.Value == uintX_t(-1))
return Sec->Addr + Sec->Size;
return Sec->Addr + D.Value;
}
case SymbolBody::DefinedRegularKind: {
auto &D = cast<DefinedRegular<ELFT>>(Body);
InputSectionBase<ELFT> *IS = D.Section;
// According to the ELF spec reference to a local symbol from outside
// the group are not allowed. Unfortunately .eh_frame breaks that rule
// and must be treated specially. For now we just replace the symbol with
// 0.
if (IS == &InputSection<ELFT>::Discarded)
return 0;
// This is an absolute symbol.
if (!IS)
return D.Value;
uintX_t Offset = D.Value;
if (D.isSection()) {
Offset += Addend;
Addend = 0;
}
uintX_t VA = (IS->OutSec ? IS->OutSec->Addr : 0) + IS->getOffset(Offset);
if (D.isTls() && !Config->Relocatable) {
if (!Out<ELFT>::TlsPhdr)
fatal(toString(D.File) +
" has a STT_TLS symbol but doesn't have a PT_TLS section");
return VA - Out<ELFT>::TlsPhdr->p_vaddr;
}
return VA;
}
case SymbolBody::DefinedCommonKind:
if (!Config->DefineCommon)
return 0;
return In<ELFT>::Common->OutSec->Addr + In<ELFT>::Common->OutSecOff +
cast<DefinedCommon>(Body).Offset;
case SymbolBody::SharedKind: {
auto &SS = cast<SharedSymbol<ELFT>>(Body);
if (!SS.NeedsCopyOrPltAddr)
return 0;
if (SS.isFunc())
return Body.getPltVA<ELFT>();
return SS.getBssSectionForCopy()->Addr + SS.CopyOffset;
}
case SymbolBody::UndefinedKind:
return 0;
case SymbolBody::LazyArchiveKind:
case SymbolBody::LazyObjectKind:
assert(Body.symbol()->IsUsedInRegularObj && "lazy symbol reached writer");
return 0;
}
llvm_unreachable("invalid symbol kind");
}
