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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 "llvm/Support/raw_ostream.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>
void InputSection<ELFT>::relocateOne(uint8_t *Buf, const Elf_Rel &Rel,
uint32_t Type, uintX_t BaseAddr,
uintX_t SymVA) {
uintX_t Offset = Rel.r_offset;
uint8_t *Location = Buf + Offset;
switch (Type) {
case R_386_32:
support::endian::write32le(Location, SymVA);
break;
default:
llvm::errs() << Twine("unrecognized reloc ") + Twine(Type) << '\n';
break;
}
}
template <class ELFT>
void InputSection<ELFT>::relocateOne(uint8_t *Buf, const Elf_Rela &Rel,
uint32_t Type, uintX_t BaseAddr,
uintX_t SymVA) {
uintX_t Offset = Rel.r_offset;
uint8_t *Location = Buf + Offset;
switch (Type) {
case R_X86_64_PC32:
support::endian::write32le(Location,
SymVA + (Rel.r_addend - (BaseAddr + Offset)));
break;
case R_X86_64_64:
support::endian::write64le(Location, SymVA + Rel.r_addend);
break;
case R_X86_64_32: {
case R_X86_64_32S:
uint64_t VA = SymVA + Rel.r_addend;
if (Type == R_X86_64_32 && !isUInt<32>(VA))
error("R_X86_64_32 out of range");
else if (!isInt<32>(VA))
error("R_X86_64_32S out of range");
support::endian::write32le(Location, VA);
break;
}
default:
llvm::errs() << Twine("unrecognized reloc ") + Twine(Type) << '\n';
break;
}
}
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 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;
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 = DC->OutputSec->getVA() + DC->OffsetInBSS;
break;
}
case SymbolBody::SharedKind:
if (relocNeedsPLT(Type)) {
SymVA = PltSec.getEntryAddr(*Body);
Type = R_X86_64_PC32;
} else if (relocNeedsGOT(Type)) {
SymVA = GotSec.getEntryAddr(*Body);
Type = R_X86_64_PC32;
} 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");
}
}
relocateOne(Buf, RI, Type, BaseAddr, SymVA);
}
}
template <class ELFT>
void InputSection<ELFT>::writeTo(uint8_t *Buf, 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());
const 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, PltSec, GotSec);
else
relocate(Base, EObj->rels(RelSec), *File, BaseAddr, 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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