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//===- Symbols.cpp --------------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "Symbols.h"
#include "InputSection.h"
#include "Error.h"
#include "InputFiles.h"
#include "llvm/ADT/STLExtras.h"
using namespace llvm;
using namespace llvm::object;
using namespace llvm::ELF;
using namespace lld;
using namespace lld::elf2;
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);
}
// Returns 1, 0 or -1 if this symbol should take precedence
// over the Other, tie or lose, respectively.
template <class ELFT> int SymbolBody::compare(SymbolBody *Other) {
typedef typename ELFFile<ELFT>::uintX_t uintX_t;
assert(!isLazy() && !Other->isLazy());
std::pair<bool, bool> L(isDefined(), !isWeak());
std::pair<bool, bool> R(Other->isDefined(), !Other->isWeak());
// Normalize
if (L > R)
return -Other->compare<ELFT>(this);
Visibility = Other->Visibility =
getMinVisibility(Visibility, Other->Visibility);
if (IsUsedInRegularObj || Other->IsUsedInRegularObj)
IsUsedInRegularObj = Other->IsUsedInRegularObj = true;
if (L != R)
return -1;
if (!L.first || !L.second)
return 1;
if (isShared())
return -1;
if (Other->isShared())
return 1;
if (isCommon()) {
if (!Other->isCommon())
return -1;
auto *ThisC = cast<DefinedCommon>(this);
auto *OtherC = cast<DefinedCommon>(Other);
uintX_t Align = std::max(ThisC->MaxAlignment, OtherC->MaxAlignment);
if (ThisC->Size >= OtherC->Size) {
ThisC->MaxAlignment = Align;
return 1;
}
OtherC->MaxAlignment = Align;
return -1;
}
if (Other->isCommon())
return 1;
return 0;
}
Defined::Defined(Kind K, StringRef Name, bool IsWeak, uint8_t Visibility,
bool IsTls)
: SymbolBody(K, Name, IsWeak, Visibility, IsTls) {}
Undefined::Undefined(SymbolBody::Kind K, StringRef N, bool IsWeak,
uint8_t Visibility, bool IsTls)
: SymbolBody(K, N, IsWeak, Visibility, IsTls), CanKeepUndefined(false) {}
Undefined::Undefined(StringRef N, bool IsWeak, uint8_t Visibility,
bool CanKeepUndefined)
: Undefined(SymbolBody::UndefinedKind, N, IsWeak, Visibility,
/*IsTls*/ false) {
this->CanKeepUndefined = CanKeepUndefined;
}
template <typename ELFT>
UndefinedElf<ELFT>::UndefinedElf(StringRef N, const Elf_Sym &Sym)
: Undefined(SymbolBody::UndefinedElfKind, N,
Sym.getBinding() == llvm::ELF::STB_WEAK, Sym.getVisibility(),
Sym.getType() == llvm::ELF::STT_TLS),
Sym(Sym) {}
template <typename ELFT>
DefinedSynthetic<ELFT>::DefinedSynthetic(StringRef N, uintX_t Value,
OutputSectionBase<ELFT> &Section)
: Defined(SymbolBody::DefinedSyntheticKind, N, false, STV_DEFAULT, false),
Value(Value), Section(Section) {}
DefinedCommon::DefinedCommon(StringRef N, uint64_t Size, uint64_t Alignment,
bool IsWeak, uint8_t Visibility)
: Defined(SymbolBody::DefinedCommonKind, N, IsWeak, Visibility, false) {
MaxAlignment = Alignment;
this->Size = Size;
}
std::unique_ptr<InputFile> Lazy::getMember() {
MemoryBufferRef MBRef = File->getMember(&Sym);
// getMember returns an empty buffer if the member was already
// read from the library.
if (MBRef.getBuffer().empty())
return std::unique_ptr<InputFile>(nullptr);
return createELFFile<ObjectFile>(MBRef);
}
template <class ELFT> static void doInitSymbols() {
ElfSym<ELFT>::End.setBinding(STB_GLOBAL);
ElfSym<ELFT>::IgnoreUndef.setBinding(STB_WEAK);
ElfSym<ELFT>::IgnoreUndef.setVisibility(STV_HIDDEN);
}
void lld::elf2::initSymbols() {
doInitSymbols<ELF32LE>();
doInitSymbols<ELF32BE>();
doInitSymbols<ELF64LE>();
doInitSymbols<ELF64BE>();
}
template int SymbolBody::compare<ELF32LE>(SymbolBody *Other);
template int SymbolBody::compare<ELF32BE>(SymbolBody *Other);
template int SymbolBody::compare<ELF64LE>(SymbolBody *Other);
template int SymbolBody::compare<ELF64BE>(SymbolBody *Other);
template class lld::elf2::UndefinedElf<ELF32LE>;
template class lld::elf2::UndefinedElf<ELF32BE>;
template class lld::elf2::UndefinedElf<ELF64LE>;
template class lld::elf2::UndefinedElf<ELF64BE>;
template class lld::elf2::DefinedSynthetic<ELF32LE>;
template class lld::elf2::DefinedSynthetic<ELF32BE>;
template class lld::elf2::DefinedSynthetic<ELF64LE>;
template class lld::elf2::DefinedSynthetic<ELF64BE>;
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