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//===- InputSection.cpp ---------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "InputSection.h"
#include "Error.h"
#include "InputFiles.h"
#include "OutputSections.h"
#include "Target.h"
using namespace llvm;
using namespace llvm::ELF;
using namespace llvm::object;
using namespace lld;
using namespace lld::elf2;
template <class ELFT>
InputSection<ELFT>::InputSection(ObjectFile<ELFT> *F, const Elf_Shdr *Header)
: File(F), Header(Header) {}
template <class ELFT>
template <bool isRela>
void InputSection<ELFT>::relocate(
uint8_t *Buf, iterator_range<const Elf_Rel_Impl<ELFT, isRela> *> Rels,
const ObjectFile<ELFT> &File, uintX_t BaseAddr,
const OutputSection<ELFT> &BssSec, const PltSection<ELFT> &PltSec,
const GotSection<ELFT> &GotSec) {
typedef Elf_Rel_Impl<ELFT, isRela> RelType;
bool IsMips64EL = File.getObj().isMips64EL();
for (const RelType &RI : Rels) {
uint32_t SymIndex = RI.getSymbol(IsMips64EL);
uint32_t Type = RI.getType(IsMips64EL);
uintX_t SymVA;
// Handle relocations for local symbols -- they never get
// resolved so we don't allocate a SymbolBody.
const Elf_Shdr *SymTab = File.getSymbolTable();
if (SymIndex < SymTab->sh_info) {
const Elf_Sym *Sym = File.getObj().getRelocationSymbol(&RI, SymTab);
if (!Sym)
continue;
SymVA = getLocalSymVA(Sym, File);
} else {
const SymbolBody *Body = File.getSymbolBody(SymIndex);
if (!Body)
continue;
uint32_t OrigType = Type;
switch (Body->kind()) {
case SymbolBody::DefinedRegularKind:
SymVA = getSymVA<ELFT>(cast<DefinedRegular<ELFT>>(Body));
break;
case SymbolBody::DefinedAbsoluteKind:
SymVA = cast<DefinedAbsolute<ELFT>>(Body)->Sym.st_value;
break;
case SymbolBody::DefinedCommonKind: {
auto *DC = cast<DefinedCommon<ELFT>>(Body);
SymVA = BssSec.getVA() + DC->OffsetInBSS;
break;
}
case SymbolBody::SharedKind:
if (Target->relocNeedsPlt(Type))
Type = Target->getPCRelReloc();
else if (Target->relocNeedsGot(Type))
Type = Target->getPCRelReloc();
else
continue;
break;
case SymbolBody::UndefinedKind:
assert(Body->isWeak() && "Undefined symbol reached writer");
SymVA = 0;
break;
case SymbolBody::LazyKind:
llvm_unreachable("Lazy symbol reached writer");
}
if (Target->relocNeedsPlt(OrigType))
SymVA = PltSec.getEntryAddr(*Body);
else if (Target->relocNeedsGot(OrigType))
SymVA = GotSec.getEntryAddr(*Body);
}
Target->relocateOne(Buf, reinterpret_cast<const void *>(&RI), Type,
BaseAddr, SymVA);
}
}
template <class ELFT>
void InputSection<ELFT>::writeTo(uint8_t *Buf,
const OutputSection<ELFT> &BssSec,
const PltSection<ELFT> &PltSec,
const GotSection<ELFT> &GotSec) {
if (Header->sh_type == SHT_NOBITS)
return;
// Copy section contents from source object file to output file.
ArrayRef<uint8_t> Data = *File->getObj().getSectionContents(Header);
memcpy(Buf + OutputSectionOff, Data.data(), Data.size());
ObjectFile<ELFT> *File = getFile();
ELFFile<ELFT> &EObj = File->getObj();
uint8_t *Base = Buf + getOutputSectionOff();
uintX_t BaseAddr = Out->getVA() + getOutputSectionOff();
// Iterate over all relocation sections that apply to this section.
for (const Elf_Shdr *RelSec : RelocSections) {
if (RelSec->sh_type == SHT_RELA)
relocate(Base, EObj.relas(RelSec), *File, BaseAddr, BssSec, PltSec,
GotSec);
else
relocate(Base, EObj.rels(RelSec), *File, BaseAddr, BssSec, PltSec,
GotSec);
}
}
template <class ELFT> StringRef InputSection<ELFT>::getSectionName() const {
ErrorOr<StringRef> Name = File->getObj().getSectionName(Header);
error(Name);
return *Name;
}
namespace lld {
namespace elf2 {
template class InputSection<object::ELF32LE>;
template class InputSection<object::ELF32BE>;
template class InputSection<object::ELF64LE>;
template class InputSection<object::ELF64BE>;
}
}
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