class ELFObjectWriter : public MCObjectWriter {
static bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind);
- static bool RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant);
static uint64_t SymbolValue(const MCSymbol &Sym, const MCAsmLayout &Layout);
static bool isInSymtab(const MCAsmLayout &Layout, const MCSymbol &Symbol,
bool Used, bool Renamed);
/// @}
- bool NeedsGOT;
-
// This holds the symbol table index of the last local symbol.
unsigned LastLocalSymbolIndex;
// This holds the .strtab section index.
public:
ELFObjectWriter(MCELFObjectTargetWriter *MOTW, raw_pwrite_stream &OS,
bool IsLittleEndian)
- : MCObjectWriter(OS, IsLittleEndian), TargetObjectWriter(MOTW),
- NeedsGOT(false) {}
+ : MCObjectWriter(OS, IsLittleEndian), TargetObjectWriter(MOTW) {}
void reset() override {
UsedInReloc.clear();
LocalSymbolData.clear();
ExternalSymbolData.clear();
UndefinedSymbolData.clear();
- NeedsGOT = false;
SectionTable.clear();
MCObjectWriter::reset();
}
typedef std::map<const MCSectionELF *, std::pair<uint64_t, uint64_t>>
SectionOffsetsTy;
- void writeSymbolTable(MCContext &Ctx, const MCAsmLayout &Layout,
- SectionOffsetsTy &SectionOffsets);
-
bool shouldRelocateWithSymbol(const MCAssembler &Asm,
const MCSymbolRefExpr *RefA,
const MCSymbol *Sym, uint64_t C,
/// \param RevGroupMap - Maps a signature symbol to the group section.
void computeSymbolTable(MCAssembler &Asm, const MCAsmLayout &Layout,
const SectionIndexMapTy &SectionIndexMap,
- const RevGroupMapTy &RevGroupMap);
+ const RevGroupMapTy &RevGroupMap,
+ SectionOffsetsTy &SectionOffsets);
MCSectionELF *createRelocationSection(MCContext &Ctx,
const MCSectionELF &Sec);
const SectionIndexMapTy &SectionIndexMap,
const SectionOffsetsTy &SectionOffsets);
- void writeSectionData(const MCAssembler &Asm, const MCSectionData &SD,
+ void writeSectionData(const MCAssembler &Asm, MCSection &Sec,
const MCAsmLayout &Layout);
void WriteSecHdrEntry(uint32_t Name, uint32_t Type, uint64_t Flags,
return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel;
}
-bool ELFObjectWriter::RelocNeedsGOT(MCSymbolRefExpr::VariantKind Variant) {
- switch (Variant) {
- default:
- return false;
- case MCSymbolRefExpr::VK_GOT:
- case MCSymbolRefExpr::VK_PLT:
- case MCSymbolRefExpr::VK_GOTPCREL:
- case MCSymbolRefExpr::VK_GOTOFF:
- case MCSymbolRefExpr::VK_TPOFF:
- case MCSymbolRefExpr::VK_TLSGD:
- case MCSymbolRefExpr::VK_GOTTPOFF:
- case MCSymbolRefExpr::VK_INDNTPOFF:
- case MCSymbolRefExpr::VK_NTPOFF:
- case MCSymbolRefExpr::VK_GOTNTPOFF:
- case MCSymbolRefExpr::VK_TLSLDM:
- case MCSymbolRefExpr::VK_DTPOFF:
- case MCSymbolRefExpr::VK_TLSLD:
- return true;
- }
-}
-
ELFObjectWriter::~ELFObjectWriter()
{}
const MCAsmLayout &Layout) {
MCSymbolData &OrigData = MSD.Symbol->getData();
assert((!OrigData.getFragment() ||
- (&OrigData.getFragment()->getParent()->getSection() ==
- &MSD.Symbol->getSection())) &&
+ (OrigData.getFragment()->getParent() == &MSD.Symbol->getSection())) &&
"The symbol's section doesn't match the fragment's symbol");
const MCSymbol *Base = Layout.getBaseSymbol(*MSD.Symbol);
MSD.SectionIndex, IsReserved);
}
-void ELFObjectWriter::writeSymbolTable(MCContext &Ctx,
- const MCAsmLayout &Layout,
- SectionOffsetsTy &SectionOffsets) {
- const MCSectionELF *SymtabSection = SectionTable[SymbolTableIndex - 1];
-
- // The string table must be emitted first because we need the index
- // into the string table for all the symbol names.
-
- SymbolTableWriter Writer(*this, is64Bit());
-
- uint64_t Padding =
- OffsetToAlignment(OS.tell(), SymtabSection->getAlignment());
- WriteZeros(Padding);
-
- uint64_t SecStart = OS.tell();
-
- // The first entry is the undefined symbol entry.
- Writer.writeSymbol(0, 0, 0, 0, 0, 0, false);
-
- for (unsigned i = 0, e = FileSymbolData.size(); i != e; ++i) {
- Writer.writeSymbol(FileSymbolData[i], ELF::STT_FILE | ELF::STB_LOCAL, 0, 0,
- ELF::STV_DEFAULT, ELF::SHN_ABS, true);
- }
-
- // Write the symbol table entries.
- LastLocalSymbolIndex = FileSymbolData.size() + LocalSymbolData.size() + 1;
-
- for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
- ELFSymbolData &MSD = LocalSymbolData[i];
- WriteSymbol(Writer, MSD, Layout);
- }
-
- for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
- ELFSymbolData &MSD = ExternalSymbolData[i];
- MCSymbolData &Data = MSD.Symbol->getData();
- assert(((Data.getFlags() & ELF_STB_Global) ||
- (Data.getFlags() & ELF_STB_Weak)) &&
- "External symbol requires STB_GLOBAL or STB_WEAK flag");
- WriteSymbol(Writer, MSD, Layout);
- if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
- LastLocalSymbolIndex++;
- }
-
- for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
- ELFSymbolData &MSD = UndefinedSymbolData[i];
- MCSymbolData &Data = MSD.Symbol->getData();
- WriteSymbol(Writer, MSD, Layout);
- if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
- LastLocalSymbolIndex++;
- }
-
- uint64_t SecEnd = OS.tell();
- SectionOffsets[SymtabSection] = std::make_pair(SecStart, SecEnd);
-
- ArrayRef<uint32_t> ShndxIndexes = Writer.getShndxIndexes();
- if (ShndxIndexes.empty()) {
- assert(SymtabShndxSectionIndex == 0);
- return;
- }
- assert(SymtabShndxSectionIndex != 0);
-
- SecStart = OS.tell();
- const MCSectionELF *SymtabShndxSection =
- SectionTable[SymtabShndxSectionIndex - 1];
- for (uint32_t Index : ShndxIndexes)
- write(Index);
- SecEnd = OS.tell();
- SectionOffsets[SymtabShndxSection] = std::make_pair(SecStart, SecEnd);
-}
-
// It is always valid to create a relocation with a symbol. It is preferable
// to use a relocation with a section if that is possible. Using the section
// allows us to omit some local symbols from the symbol table.
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
bool &IsPCRel, uint64_t &FixedValue) {
- const MCSectionData *FixupSectionD = Fragment->getParent();
- const MCSectionELF &FixupSection =
- cast<MCSectionELF>(FixupSectionD->getSection());
+ const MCSectionELF &FixupSection = cast<MCSectionELF>(*Fragment->getParent());
uint64_t C = Target.getConstant();
uint64_t FixupOffset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();
FixedValue = C;
- // FIXME: What is this!?!?
- MCSymbolRefExpr::VariantKind Modifier =
- RefA ? RefA->getKind() : MCSymbolRefExpr::VK_None;
- if (RelocNeedsGOT(Modifier))
- NeedsGOT = true;
-
if (!RelocateWithSymbol) {
const MCSection *SecA =
(SymA && !SymA->isUndefined()) ? &SymA->getSection() : nullptr;
auto *ELFSec = cast_or_null<MCSectionELF>(SecA);
- MCSymbol *SectionSymbol =
- ELFSec ? Asm.getContext().getOrCreateSectionSymbol(*ELFSec)
- : nullptr;
+ const MCSymbol *SectionSymbol = ELFSec ? ELFSec->getBeginSymbol() : nullptr;
ELFRelocationEntry Rec(FixupOffset, SectionSymbol, Type, Addend);
Relocations[&FixupSection].push_back(Rec);
return;
if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal)
return false;
+ if (MCELF::GetType(Data) == ELF::STT_SECTION)
+ return true;
+
if (Symbol.isTemporary())
return false;
void ELFObjectWriter::computeSymbolTable(
MCAssembler &Asm, const MCAsmLayout &Layout,
- const SectionIndexMapTy &SectionIndexMap,
- const RevGroupMapTy &RevGroupMap) {
+ const SectionIndexMapTy &SectionIndexMap, const RevGroupMapTy &RevGroupMap,
+ SectionOffsetsTy &SectionOffsets) {
MCContext &Ctx = Asm.getContext();
+ SymbolTableWriter Writer(*this, is64Bit());
+
// Symbol table
unsigned EntrySize = is64Bit() ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
MCSectionELF *SymtabSection =
SymtabSection->setAlignment(is64Bit() ? 8 : 4);
SymbolTableIndex = addToSectionTable(SymtabSection);
- // FIXME: Is this the correct place to do this?
- // FIXME: Why is an undefined reference to _GLOBAL_OFFSET_TABLE_ needed?
- if (NeedsGOT) {
- StringRef Name = "_GLOBAL_OFFSET_TABLE_";
- MCSymbol *Sym = Asm.getContext().getOrCreateSymbol(Name);
- MCSymbolData &Data = Asm.getOrCreateSymbolData(*Sym);
- Data.setExternal(true);
- MCELF::SetBinding(Data, ELF::STB_GLOBAL);
- }
+ uint64_t Padding =
+ OffsetToAlignment(OS.tell(), SymtabSection->getAlignment());
+ WriteZeros(Padding);
+
+ uint64_t SecStart = OS.tell();
+
+ // The first entry is the undefined symbol entry.
+ Writer.writeSymbol(0, 0, 0, 0, 0, 0, false);
// Add the data for the symbols.
bool HasLargeSectionIndex = false;
SymtabShndxSection->setAlignment(4);
}
- for (auto i = Asm.file_names_begin(), e = Asm.file_names_end(); i != e; ++i)
- StrTabBuilder.add(*i);
+ for (const std::string &Name : Asm.getFileNames())
+ StrTabBuilder.add(Name);
StrTabBuilder.finalize(StringTableBuilder::ELF);
- for (auto i = Asm.file_names_begin(), e = Asm.file_names_end(); i != e; ++i)
- FileSymbolData.push_back(StrTabBuilder.getOffset(*i));
-
- for (ELFSymbolData &MSD : LocalSymbolData)
- MSD.StringIndex = MCELF::GetType(MSD.Symbol->getData()) == ELF::STT_SECTION
- ? 0
- : StrTabBuilder.getOffset(MSD.Name);
- for (ELFSymbolData &MSD : ExternalSymbolData)
- MSD.StringIndex = StrTabBuilder.getOffset(MSD.Name);
- for (ELFSymbolData& MSD : UndefinedSymbolData)
- MSD.StringIndex = StrTabBuilder.getOffset(MSD.Name);
+ for (const std::string &Name : Asm.getFileNames())
+ FileSymbolData.push_back(StrTabBuilder.getOffset(Name));
// Symbols are required to be in lexicographic order.
array_pod_sort(LocalSymbolData.begin(), LocalSymbolData.end());
// Set the symbol indices. Local symbols must come before all other
// symbols with non-local bindings.
unsigned Index = FileSymbolData.size() + 1;
- for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
- LocalSymbolData[i].Symbol->setIndex(Index++);
- for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
- ExternalSymbolData[i].Symbol->setIndex(Index++);
- for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
- UndefinedSymbolData[i].Symbol->setIndex(Index++);
+ for (ELFSymbolData &MSD : LocalSymbolData) {
+ MSD.StringIndex = MCELF::GetType(MSD.Symbol->getData()) == ELF::STT_SECTION
+ ? 0
+ : StrTabBuilder.getOffset(MSD.Name);
+ MSD.Symbol->setIndex(Index++);
+ }
+ for (ELFSymbolData &MSD : ExternalSymbolData) {
+ MSD.StringIndex = StrTabBuilder.getOffset(MSD.Name);
+ MSD.Symbol->setIndex(Index++);
+ }
+ for (ELFSymbolData &MSD : UndefinedSymbolData) {
+ MSD.StringIndex = StrTabBuilder.getOffset(MSD.Name);
+ MSD.Symbol->setIndex(Index++);
+ }
+
+ for (unsigned i = 0, e = FileSymbolData.size(); i != e; ++i) {
+ Writer.writeSymbol(FileSymbolData[i], ELF::STT_FILE | ELF::STB_LOCAL, 0, 0,
+ ELF::STV_DEFAULT, ELF::SHN_ABS, true);
+ }
+
+ // Write the symbol table entries.
+ LastLocalSymbolIndex = FileSymbolData.size() + LocalSymbolData.size() + 1;
+
+ for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
+ ELFSymbolData &MSD = LocalSymbolData[i];
+ WriteSymbol(Writer, MSD, Layout);
+ }
+
+ for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
+ ELFSymbolData &MSD = ExternalSymbolData[i];
+ MCSymbolData &Data = MSD.Symbol->getData();
+ assert(((Data.getFlags() & ELF_STB_Global) ||
+ (Data.getFlags() & ELF_STB_Weak)) &&
+ "External symbol requires STB_GLOBAL or STB_WEAK flag");
+ WriteSymbol(Writer, MSD, Layout);
+ if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
+ LastLocalSymbolIndex++;
+ }
+
+ for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
+ ELFSymbolData &MSD = UndefinedSymbolData[i];
+ MCSymbolData &Data = MSD.Symbol->getData();
+ WriteSymbol(Writer, MSD, Layout);
+ if (MCELF::GetBinding(Data) == ELF::STB_LOCAL)
+ LastLocalSymbolIndex++;
+ }
+
+ uint64_t SecEnd = OS.tell();
+ SectionOffsets[SymtabSection] = std::make_pair(SecStart, SecEnd);
+
+ ArrayRef<uint32_t> ShndxIndexes = Writer.getShndxIndexes();
+ if (ShndxIndexes.empty()) {
+ assert(SymtabShndxSectionIndex == 0);
+ return;
+ }
+ assert(SymtabShndxSectionIndex != 0);
+
+ SecStart = OS.tell();
+ const MCSectionELF *SymtabShndxSection =
+ SectionTable[SymtabShndxSectionIndex - 1];
+ for (uint32_t Index : ShndxIndexes)
+ write(Index);
+ SecEnd = OS.tell();
+ SectionOffsets[SymtabShndxSection] = std::make_pair(SecStart, SecEnd);
}
MCSectionELF *
static SmallVector<char, 128>
getUncompressedData(const MCAsmLayout &Layout,
- const MCSectionData::FragmentListType &Fragments) {
+ const MCSection::FragmentListType &Fragments) {
SmallVector<char, 128> UncompressedData;
for (const MCFragment &F : Fragments) {
const SmallVectorImpl<char> *Contents;
return true;
}
-void ELFObjectWriter::writeSectionData(const MCAssembler &Asm,
- const MCSectionData &SD,
+void ELFObjectWriter::writeSectionData(const MCAssembler &Asm, MCSection &Sec,
const MCAsmLayout &Layout) {
- MCSectionELF &Section = static_cast<MCSectionELF &>(SD.getSection());
+ MCSectionELF &Section = static_cast<MCSectionELF &>(Sec);
StringRef SectionName = Section.getSectionName();
// Compressing debug_frame requires handling alignment fragments which is
// for writing to arbitrary buffers) for little benefit.
if (!Asm.getContext().getAsmInfo()->compressDebugSections() ||
!SectionName.startswith(".debug_") || SectionName == ".debug_frame") {
- Asm.writeSectionData(&SD, Layout);
+ Asm.writeSectionData(&Section, Layout);
return;
}
// Gather the uncompressed data from all the fragments.
- const MCSectionData::FragmentListType &Fragments = SD.getFragmentList();
+ const MCSection::FragmentListType &Fragments = Section.getFragmentList();
SmallVector<char, 128> UncompressedData =
getUncompressedData(Layout, Fragments);
StringRef(UncompressedData.data(), UncompressedData.size()),
CompressedContents);
if (Success != zlib::StatusOK) {
- Asm.writeSectionData(&SD, Layout);
+ Asm.writeSectionData(&Section, Layout);
return;
}
if (!prependCompressionHeader(UncompressedData.size(), CompressedContents)) {
- Asm.writeSectionData(&SD, Layout);
+ Asm.writeSectionData(&Section, Layout);
return;
}
Asm.getContext().renameELFSection(&Section,
const std::pair<uint64_t, uint64_t> &Offsets =
SectionOffsets.find(Section)->second;
uint64_t Size;
- if (Type == ELF::SHT_NOBITS) {
- const MCSectionData &SD = Asm.getSectionData(*Section);
- Size = Layout.getSectionAddressSize(&SD);
- } else {
+ if (Type == ELF::SHT_NOBITS)
+ Size = Layout.getSectionAddressSize(Section);
+ else
Size = Offsets.second - Offsets.first;
- }
writeSection(SectionIndexMap, GroupSymbolIndex, Offsets.first, Size,
*Section);
SectionOffsetsTy SectionOffsets;
std::vector<MCSectionELF *> Groups;
std::vector<MCSectionELF *> Relocations;
- for (const MCSectionData &SD : Asm) {
- const MCSectionELF &Section = static_cast<MCSectionELF &>(SD.getSection());
+ for (MCSection &Sec : Asm) {
+ MCSectionELF &Section = static_cast<MCSectionELF &>(Sec);
uint64_t Padding = OffsetToAlignment(OS.tell(), Section.getAlignment());
WriteZeros(Padding);
uint64_t SecStart = OS.tell();
const MCSymbol *SignatureSymbol = Section.getGroup();
- writeSectionData(Asm, SD, Layout);
+ writeSectionData(Asm, Section, Layout);
uint64_t SecEnd = OS.tell();
SectionOffsets[&Section] = std::make_pair(SecStart, SecEnd);
}
// Compute symbol table information.
- computeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap);
+ computeSymbolTable(Asm, Layout, SectionIndexMap, RevGroupMap, SectionOffsets);
for (MCSectionELF *RelSection : Relocations) {
uint64_t Padding = OffsetToAlignment(OS.tell(), RelSection->getAlignment());
SectionOffsets[RelSection] = std::make_pair(SecStart, SecEnd);
}
- writeSymbolTable(Ctx, Layout, SectionOffsets);
-
{
uint64_t SecStart = OS.tell();
const MCSectionELF *Sec = createStringTable(Ctx);
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