MachObjectWriter.cpp [plain text]
#include "llvm/MC/MCMachObjectWriter.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFixupKindInfo.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSymbolMachO.h"
#include "llvm/MC/MCValue.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MachO.h"
#include "llvm/Support/raw_ostream.h"
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "mc"
void MachObjectWriter::reset() {
Relocations.clear();
IndirectSymBase.clear();
StringTable.clear();
LocalSymbolData.clear();
ExternalSymbolData.clear();
UndefinedSymbolData.clear();
MCObjectWriter::reset();
}
bool MachObjectWriter::doesSymbolRequireExternRelocation(const MCSymbol &S) {
if (S.isUndefined())
return true;
if (cast<MCSymbolMachO>(S).isWeakDefinition())
return true;
return false;
}
bool MachObjectWriter::
MachSymbolData::operator<(const MachSymbolData &RHS) const {
return Symbol->getName() < RHS.Symbol->getName();
}
bool MachObjectWriter::isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind) {
const MCFixupKindInfo &FKI = Asm.getBackend().getFixupKindInfo(
(MCFixupKind) Kind);
return FKI.Flags & MCFixupKindInfo::FKF_IsPCRel;
}
uint64_t MachObjectWriter::getFragmentAddress(const MCFragment *Fragment,
const MCAsmLayout &Layout) const {
return getSectionAddress(Fragment->getParent()) +
Layout.getFragmentOffset(Fragment);
}
uint64_t MachObjectWriter::getSymbolAddress(const MCSymbol &S,
const MCAsmLayout &Layout) const {
if (S.isVariable()) {
if (const MCConstantExpr *C =
dyn_cast<const MCConstantExpr>(S.getVariableValue()))
return C->getValue();
MCValue Target;
if (!S.getVariableValue()->evaluateAsRelocatable(Target, &Layout, nullptr))
report_fatal_error("unable to evaluate offset for variable '" +
S.getName() + "'");
if (Target.getSymA() && Target.getSymA()->getSymbol().isUndefined())
report_fatal_error("unable to evaluate offset to undefined symbol '" +
Target.getSymA()->getSymbol().getName() + "'");
if (Target.getSymB() && Target.getSymB()->getSymbol().isUndefined())
report_fatal_error("unable to evaluate offset to undefined symbol '" +
Target.getSymB()->getSymbol().getName() + "'");
uint64_t Address = Target.getConstant();
if (Target.getSymA())
Address += getSymbolAddress(Target.getSymA()->getSymbol(), Layout);
if (Target.getSymB())
Address += getSymbolAddress(Target.getSymB()->getSymbol(), Layout);
return Address;
}
return getSectionAddress(S.getFragment()->getParent()) +
Layout.getSymbolOffset(S);
}
uint64_t MachObjectWriter::getPaddingSize(const MCSection *Sec,
const MCAsmLayout &Layout) const {
uint64_t EndAddr = getSectionAddress(Sec) + Layout.getSectionAddressSize(Sec);
unsigned Next = Sec->getLayoutOrder() + 1;
if (Next >= Layout.getSectionOrder().size())
return 0;
const MCSection &NextSec = *Layout.getSectionOrder()[Next];
if (NextSec.isVirtualSection())
return 0;
return OffsetToAlignment(EndAddr, NextSec.getAlignment());
}
void MachObjectWriter::writeHeader(MachO::HeaderFileType Type,
unsigned NumLoadCommands,
unsigned LoadCommandsSize,
bool SubsectionsViaSymbols) {
uint32_t Flags = 0;
if (SubsectionsViaSymbols)
Flags |= MachO::MH_SUBSECTIONS_VIA_SYMBOLS;
uint64_t Start = getStream().tell();
(void) Start;
write32(is64Bit() ? MachO::MH_MAGIC_64 : MachO::MH_MAGIC);
write32(TargetObjectWriter->getCPUType());
write32(TargetObjectWriter->getCPUSubtype());
write32(Type);
write32(NumLoadCommands);
write32(LoadCommandsSize);
write32(Flags);
if (is64Bit())
write32(0);
assert(
getStream().tell() - Start ==
(is64Bit() ? sizeof(MachO::mach_header_64) : sizeof(MachO::mach_header)));
}
void MachObjectWriter::writeSegmentLoadCommand(
StringRef Name, unsigned NumSections, uint64_t VMAddr, uint64_t VMSize,
uint64_t SectionDataStartOffset, uint64_t SectionDataSize, uint32_t MaxProt,
uint32_t InitProt) {
uint64_t Start = getStream().tell();
(void) Start;
unsigned SegmentLoadCommandSize =
is64Bit() ? sizeof(MachO::segment_command_64):
sizeof(MachO::segment_command);
write32(is64Bit() ? MachO::LC_SEGMENT_64 : MachO::LC_SEGMENT);
write32(SegmentLoadCommandSize +
NumSections * (is64Bit() ? sizeof(MachO::section_64) :
sizeof(MachO::section)));
assert(Name.size() <= 16);
writeBytes(Name, 16);
if (is64Bit()) {
write64(VMAddr); write64(VMSize); write64(SectionDataStartOffset); write64(SectionDataSize); } else {
write32(VMAddr); write32(VMSize); write32(SectionDataStartOffset); write32(SectionDataSize); }
write32(MaxProt);
write32(InitProt);
write32(NumSections);
write32(0);
assert(getStream().tell() - Start == SegmentLoadCommandSize);
}
void MachObjectWriter::writeSection(const MCAsmLayout &Layout,
const MCSection &Sec, uint64_t VMAddr,
uint64_t FileOffset, unsigned Flags,
uint64_t RelocationsStart,
unsigned NumRelocations) {
uint64_t SectionSize = Layout.getSectionAddressSize(&Sec);
const MCSectionMachO &Section = cast<MCSectionMachO>(Sec);
if (Section.isVirtualSection()) {
assert(Layout.getSectionFileSize(&Sec) == 0 && "Invalid file size!");
FileOffset = 0;
}
uint64_t Start = getStream().tell();
(void) Start;
writeBytes(Section.getSectionName(), 16);
writeBytes(Section.getSegmentName(), 16);
if (is64Bit()) {
write64(VMAddr); write64(SectionSize); } else {
write32(VMAddr); write32(SectionSize); }
write32(FileOffset);
assert(isPowerOf2_32(Section.getAlignment()) && "Invalid alignment!");
write32(Log2_32(Section.getAlignment()));
write32(NumRelocations ? RelocationsStart : 0);
write32(NumRelocations);
write32(Flags);
write32(IndirectSymBase.lookup(&Sec)); write32(Section.getStubSize()); if (is64Bit())
write32(0);
assert(getStream().tell() - Start ==
(is64Bit() ? sizeof(MachO::section_64) : sizeof(MachO::section)));
}
void MachObjectWriter::writeSymtabLoadCommand(uint32_t SymbolOffset,
uint32_t NumSymbols,
uint32_t StringTableOffset,
uint32_t StringTableSize) {
uint64_t Start = getStream().tell();
(void) Start;
write32(MachO::LC_SYMTAB);
write32(sizeof(MachO::symtab_command));
write32(SymbolOffset);
write32(NumSymbols);
write32(StringTableOffset);
write32(StringTableSize);
assert(getStream().tell() - Start == sizeof(MachO::symtab_command));
}
void MachObjectWriter::writeDysymtabLoadCommand(uint32_t FirstLocalSymbol,
uint32_t NumLocalSymbols,
uint32_t FirstExternalSymbol,
uint32_t NumExternalSymbols,
uint32_t FirstUndefinedSymbol,
uint32_t NumUndefinedSymbols,
uint32_t IndirectSymbolOffset,
uint32_t NumIndirectSymbols) {
uint64_t Start = getStream().tell();
(void) Start;
write32(MachO::LC_DYSYMTAB);
write32(sizeof(MachO::dysymtab_command));
write32(FirstLocalSymbol);
write32(NumLocalSymbols);
write32(FirstExternalSymbol);
write32(NumExternalSymbols);
write32(FirstUndefinedSymbol);
write32(NumUndefinedSymbols);
write32(0); write32(0); write32(0); write32(0); write32(0); write32(0); write32(IndirectSymbolOffset);
write32(NumIndirectSymbols);
write32(0); write32(0); write32(0); write32(0);
assert(getStream().tell() - Start == sizeof(MachO::dysymtab_command));
}
MachObjectWriter::MachSymbolData *
MachObjectWriter::findSymbolData(const MCSymbol &Sym) {
for (auto *SymbolData :
{&LocalSymbolData, &ExternalSymbolData, &UndefinedSymbolData})
for (MachSymbolData &Entry : *SymbolData)
if (Entry.Symbol == &Sym)
return &Entry;
return nullptr;
}
const MCSymbol &MachObjectWriter::findAliasedSymbol(const MCSymbol &Sym) const {
const MCSymbol *S = &Sym;
while (S->isVariable()) {
const MCExpr *Value = S->getVariableValue();
const auto *Ref = dyn_cast<MCSymbolRefExpr>(Value);
if (!Ref)
return *S;
S = &Ref->getSymbol();
}
return *S;
}
void MachObjectWriter::writeNlist(MachSymbolData &MSD,
const MCAsmLayout &Layout) {
const MCSymbol *Symbol = MSD.Symbol;
const MCSymbol &Data = *Symbol;
const MCSymbol *AliasedSymbol = &findAliasedSymbol(*Symbol);
uint8_t SectionIndex = MSD.SectionIndex;
uint8_t Type = 0;
uint64_t Address = 0;
bool IsAlias = Symbol != AliasedSymbol;
const MCSymbol &OrigSymbol = *Symbol;
MachSymbolData *AliaseeInfo;
if (IsAlias) {
AliaseeInfo = findSymbolData(*AliasedSymbol);
if (AliaseeInfo)
SectionIndex = AliaseeInfo->SectionIndex;
Symbol = AliasedSymbol;
}
if (IsAlias && Symbol->isUndefined())
Type = MachO::N_INDR;
else if (Symbol->isUndefined())
Type = MachO::N_UNDF;
else if (Symbol->isAbsolute())
Type = MachO::N_ABS;
else
Type = MachO::N_SECT;
if (Data.isPrivateExtern())
Type |= MachO::N_PEXT;
if (Data.isExternal() || (!IsAlias && Symbol->isUndefined()))
Type |= MachO::N_EXT;
if (IsAlias && Symbol->isUndefined())
Address = AliaseeInfo->StringIndex;
else if (Symbol->isDefined())
Address = getSymbolAddress(OrigSymbol, Layout);
else if (Symbol->isCommon()) {
Address = Symbol->getCommonSize();
}
write32(MSD.StringIndex);
write8(Type);
write8(SectionIndex);
write16(cast<MCSymbolMachO>(Symbol)->getEncodedFlags());
if (is64Bit())
write64(Address);
else
write32(Address);
}
void MachObjectWriter::writeLinkeditLoadCommand(uint32_t Type,
uint32_t DataOffset,
uint32_t DataSize) {
uint64_t Start = getStream().tell();
(void) Start;
write32(Type);
write32(sizeof(MachO::linkedit_data_command));
write32(DataOffset);
write32(DataSize);
assert(getStream().tell() - Start == sizeof(MachO::linkedit_data_command));
}
static unsigned ComputeLinkerOptionsLoadCommandSize(
const std::vector<std::string> &Options, bool is64Bit)
{
unsigned Size = sizeof(MachO::linker_option_command);
for (const std::string &Option : Options)
Size += Option.size() + 1;
return alignTo(Size, is64Bit ? 8 : 4);
}
void MachObjectWriter::writeLinkerOptionsLoadCommand(
const std::vector<std::string> &Options)
{
unsigned Size = ComputeLinkerOptionsLoadCommandSize(Options, is64Bit());
uint64_t Start = getStream().tell();
(void) Start;
write32(MachO::LC_LINKER_OPTION);
write32(Size);
write32(Options.size());
uint64_t BytesWritten = sizeof(MachO::linker_option_command);
for (const std::string &Option : Options) {
writeBytes(Option.c_str(), Option.size() + 1);
BytesWritten += Option.size() + 1;
}
writeBytes("", OffsetToAlignment(BytesWritten, is64Bit() ? 8 : 4));
assert(getStream().tell() - Start == Size);
}
void MachObjectWriter::recordRelocation(MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
bool &IsPCRel, uint64_t &FixedValue) {
TargetObjectWriter->recordRelocation(this, Asm, Layout, Fragment, Fixup,
Target, FixedValue);
}
void MachObjectWriter::bindIndirectSymbols(MCAssembler &Asm) {
for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
ie = Asm.indirect_symbol_end(); it != ie; ++it) {
const MCSectionMachO &Section = cast<MCSectionMachO>(*it->Section);
if (Section.getType() != MachO::S_NON_LAZY_SYMBOL_POINTERS &&
Section.getType() != MachO::S_LAZY_SYMBOL_POINTERS &&
Section.getType() != MachO::S_THREAD_LOCAL_VARIABLE_POINTERS &&
Section.getType() != MachO::S_SYMBOL_STUBS) {
MCSymbol &Symbol = *it->Symbol;
report_fatal_error("indirect symbol '" + Symbol.getName() +
"' not in a symbol pointer or stub section");
}
}
unsigned IndirectIndex = 0;
for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
ie = Asm.indirect_symbol_end(); it != ie; ++it, ++IndirectIndex) {
const MCSectionMachO &Section = cast<MCSectionMachO>(*it->Section);
if (Section.getType() != MachO::S_NON_LAZY_SYMBOL_POINTERS &&
Section.getType() != MachO::S_THREAD_LOCAL_VARIABLE_POINTERS)
continue;
IndirectSymBase.insert(std::make_pair(it->Section, IndirectIndex));
Asm.registerSymbol(*it->Symbol);
}
IndirectIndex = 0;
for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
ie = Asm.indirect_symbol_end(); it != ie; ++it, ++IndirectIndex) {
const MCSectionMachO &Section = cast<MCSectionMachO>(*it->Section);
if (Section.getType() != MachO::S_LAZY_SYMBOL_POINTERS &&
Section.getType() != MachO::S_SYMBOL_STUBS)
continue;
IndirectSymBase.insert(std::make_pair(it->Section, IndirectIndex));
bool Created;
Asm.registerSymbol(*it->Symbol, &Created);
if (Created)
cast<MCSymbolMachO>(it->Symbol)->setReferenceTypeUndefinedLazy(true);
}
}
void MachObjectWriter::computeSymbolTable(
MCAssembler &Asm, std::vector<MachSymbolData> &LocalSymbolData,
std::vector<MachSymbolData> &ExternalSymbolData,
std::vector<MachSymbolData> &UndefinedSymbolData) {
DenseMap<const MCSection*, uint8_t> SectionIndexMap;
unsigned Index = 1;
for (MCAssembler::iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it, ++Index)
SectionIndexMap[&*it] = Index;
assert(Index <= 256 && "Too many sections!");
for (const MCSymbol &Symbol : Asm.symbols()) {
if (!Asm.isSymbolLinkerVisible(Symbol))
continue;
StringTable.add(Symbol.getName());
}
StringTable.finalize();
for (const MCSymbol &Symbol : Asm.symbols()) {
if (!Asm.isSymbolLinkerVisible(Symbol))
continue;
if (!Symbol.isExternal() && !Symbol.isUndefined())
continue;
MachSymbolData MSD;
MSD.Symbol = &Symbol;
MSD.StringIndex = StringTable.getOffset(Symbol.getName());
if (Symbol.isUndefined()) {
MSD.SectionIndex = 0;
UndefinedSymbolData.push_back(MSD);
} else if (Symbol.isAbsolute()) {
MSD.SectionIndex = 0;
ExternalSymbolData.push_back(MSD);
} else {
MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
assert(MSD.SectionIndex && "Invalid section index!");
ExternalSymbolData.push_back(MSD);
}
}
for (const MCSymbol &Symbol : Asm.symbols()) {
if (!Asm.isSymbolLinkerVisible(Symbol))
continue;
if (Symbol.isExternal() || Symbol.isUndefined())
continue;
MachSymbolData MSD;
MSD.Symbol = &Symbol;
MSD.StringIndex = StringTable.getOffset(Symbol.getName());
if (Symbol.isAbsolute()) {
MSD.SectionIndex = 0;
LocalSymbolData.push_back(MSD);
} else {
MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection());
assert(MSD.SectionIndex && "Invalid section index!");
LocalSymbolData.push_back(MSD);
}
}
std::sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
std::sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
Index = 0;
for (auto *SymbolData :
{&LocalSymbolData, &ExternalSymbolData, &UndefinedSymbolData})
for (MachSymbolData &Entry : *SymbolData)
Entry.Symbol->setIndex(Index++);
for (const MCSection &Section : Asm) {
for (RelAndSymbol &Rel : Relocations[&Section]) {
if (!Rel.Sym)
continue;
unsigned Index = Rel.Sym->getIndex();
assert(isInt<24>(Index));
if (IsLittleEndian)
Rel.MRE.r_word1 = (Rel.MRE.r_word1 & (~0U << 24)) | Index | (1 << 27);
else
Rel.MRE.r_word1 = (Rel.MRE.r_word1 & 0xff) | Index << 8 | (1 << 4);
}
}
}
void MachObjectWriter::computeSectionAddresses(const MCAssembler &Asm,
const MCAsmLayout &Layout) {
uint64_t StartAddress = 0;
for (const MCSection *Sec : Layout.getSectionOrder()) {
StartAddress = alignTo(StartAddress, Sec->getAlignment());
SectionAddress[Sec] = StartAddress;
StartAddress += Layout.getSectionAddressSize(Sec);
StartAddress += getPaddingSize(Sec, Layout);
}
}
void MachObjectWriter::executePostLayoutBinding(MCAssembler &Asm,
const MCAsmLayout &Layout) {
computeSectionAddresses(Asm, Layout);
bindIndirectSymbols(Asm);
}
bool MachObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
const MCAssembler &Asm, const MCSymbol &A, const MCSymbol &B,
bool InSet) const {
if (A.isVariable() || B.isVariable())
return false;
return MCObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(Asm, A, B,
InSet);
}
bool MachObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
const MCAssembler &Asm, const MCSymbol &SymA, const MCFragment &FB,
bool InSet, bool IsPCRel) const {
if (InSet)
return true;
const MCSymbol &SA = findAliasedSymbol(SymA);
const MCSection &SecA = SA.getSection();
const MCSection &SecB = *FB.getParent();
if (IsPCRel) {
bool hasReliableSymbolDifference = isX86_64();
if (!hasReliableSymbolDifference) {
if (!SA.isInSection() || &SecA != &SecB ||
(!SA.isTemporary() && FB.getAtom() != SA.getFragment()->getAtom() &&
Asm.getSubsectionsViaSymbols()))
return false;
return true;
}
else if(!FB.getAtom() &&
SA.isTemporary() && SA.isInSection() && &SecA == &SecB){
return true;
}
}
if (&SecA != &SecB)
return false;
const MCFragment *FA = SA.getFragment();
if (!FA)
return false;
if (FA->getAtom() == FB.getAtom())
return true;
return false;
}
void MachObjectWriter::writeObject(MCAssembler &Asm,
const MCAsmLayout &Layout) {
computeSymbolTable(Asm, LocalSymbolData, ExternalSymbolData,
UndefinedSymbolData);
unsigned NumSections = Asm.size();
const MCAssembler::VersionMinInfoType &VersionInfo =
Layout.getAssembler().getVersionMinInfo();
unsigned NumLoadCommands = 1;
uint64_t LoadCommandsSize = is64Bit() ?
sizeof(MachO::segment_command_64) + NumSections * sizeof(MachO::section_64):
sizeof(MachO::segment_command) + NumSections * sizeof(MachO::section);
if (VersionInfo.Major != 0) {
++NumLoadCommands;
LoadCommandsSize += sizeof(MachO::version_min_command);
}
unsigned NumDataRegions = Asm.getDataRegions().size();
if (NumDataRegions) {
++NumLoadCommands;
LoadCommandsSize += sizeof(MachO::linkedit_data_command);
}
uint64_t LOHRawSize = Asm.getLOHContainer().getEmitSize(*this, Layout);
uint64_t LOHSize = alignTo(LOHRawSize, is64Bit() ? 8 : 4);
if (LOHSize) {
++NumLoadCommands;
LoadCommandsSize += sizeof(MachO::linkedit_data_command);
}
unsigned NumSymbols = LocalSymbolData.size() + ExternalSymbolData.size() +
UndefinedSymbolData.size();
if (NumSymbols) {
NumLoadCommands += 2;
LoadCommandsSize += (sizeof(MachO::symtab_command) +
sizeof(MachO::dysymtab_command));
}
for (const auto &Option : Asm.getLinkerOptions()) {
++NumLoadCommands;
LoadCommandsSize += ComputeLinkerOptionsLoadCommandSize(Option, is64Bit());
}
uint64_t SectionDataStart = (is64Bit() ? sizeof(MachO::mach_header_64) :
sizeof(MachO::mach_header)) + LoadCommandsSize;
uint64_t SectionDataSize = 0;
uint64_t SectionDataFileSize = 0;
uint64_t VMSize = 0;
for (const MCSection &Sec : Asm) {
uint64_t Address = getSectionAddress(&Sec);
uint64_t Size = Layout.getSectionAddressSize(&Sec);
uint64_t FileSize = Layout.getSectionFileSize(&Sec);
FileSize += getPaddingSize(&Sec, Layout);
VMSize = std::max(VMSize, Address + Size);
if (Sec.isVirtualSection())
continue;
SectionDataSize = std::max(SectionDataSize, Address + Size);
SectionDataFileSize = std::max(SectionDataFileSize, Address + FileSize);
}
unsigned SectionDataPadding = OffsetToAlignment(SectionDataFileSize, 4);
SectionDataFileSize += SectionDataPadding;
writeHeader(MachO::MH_OBJECT, NumLoadCommands, LoadCommandsSize,
Asm.getSubsectionsViaSymbols());
uint32_t Prot =
MachO::VM_PROT_READ | MachO::VM_PROT_WRITE | MachO::VM_PROT_EXECUTE;
writeSegmentLoadCommand("", NumSections, 0, VMSize, SectionDataStart,
SectionDataSize, Prot, Prot);
uint64_t RelocTableEnd = SectionDataStart + SectionDataFileSize;
for (const MCSection &Section : Asm) {
const auto &Sec = cast<MCSectionMachO>(Section);
std::vector<RelAndSymbol> &Relocs = Relocations[&Sec];
unsigned NumRelocs = Relocs.size();
uint64_t SectionStart = SectionDataStart + getSectionAddress(&Sec);
unsigned Flags = Sec.getTypeAndAttributes();
if (Sec.hasInstructions())
Flags |= MachO::S_ATTR_SOME_INSTRUCTIONS;
writeSection(Layout, Sec, getSectionAddress(&Sec), SectionStart, Flags,
RelocTableEnd, NumRelocs);
RelocTableEnd += NumRelocs * sizeof(MachO::any_relocation_info);
}
if (VersionInfo.Major != 0) {
assert(VersionInfo.Update < 256 && "unencodable update target version");
assert(VersionInfo.Minor < 256 && "unencodable minor target version");
assert(VersionInfo.Major < 65536 && "unencodable major target version");
uint32_t EncodedVersion = VersionInfo.Update | (VersionInfo.Minor << 8) |
(VersionInfo.Major << 16);
MachO::LoadCommandType LCType;
switch (VersionInfo.Kind) {
case MCVM_OSXVersionMin:
LCType = MachO::LC_VERSION_MIN_MACOSX;
break;
case MCVM_IOSVersionMin:
LCType = MachO::LC_VERSION_MIN_IPHONEOS;
break;
case MCVM_TvOSVersionMin:
LCType = MachO::LC_VERSION_MIN_TVOS;
break;
case MCVM_WatchOSVersionMin:
LCType = MachO::LC_VERSION_MIN_WATCHOS;
break;
}
write32(LCType);
write32(sizeof(MachO::version_min_command));
write32(EncodedVersion);
write32(0); }
uint64_t DataInCodeTableEnd = RelocTableEnd + NumDataRegions * 8;
if (NumDataRegions) {
uint64_t DataRegionsOffset = RelocTableEnd;
uint64_t DataRegionsSize = NumDataRegions * 8;
writeLinkeditLoadCommand(MachO::LC_DATA_IN_CODE, DataRegionsOffset,
DataRegionsSize);
}
uint64_t LOHTableEnd = DataInCodeTableEnd + LOHSize;
if (LOHSize)
writeLinkeditLoadCommand(MachO::LC_LINKER_OPTIMIZATION_HINT,
DataInCodeTableEnd, LOHSize);
if (NumSymbols) {
unsigned FirstLocalSymbol = 0;
unsigned NumLocalSymbols = LocalSymbolData.size();
unsigned FirstExternalSymbol = FirstLocalSymbol + NumLocalSymbols;
unsigned NumExternalSymbols = ExternalSymbolData.size();
unsigned FirstUndefinedSymbol = FirstExternalSymbol + NumExternalSymbols;
unsigned NumUndefinedSymbols = UndefinedSymbolData.size();
unsigned NumIndirectSymbols = Asm.indirect_symbol_size();
unsigned NumSymTabSymbols =
NumLocalSymbols + NumExternalSymbols + NumUndefinedSymbols;
uint64_t IndirectSymbolSize = NumIndirectSymbols * 4;
uint64_t IndirectSymbolOffset = 0;
if (NumIndirectSymbols)
IndirectSymbolOffset = LOHTableEnd;
uint64_t SymbolTableOffset = LOHTableEnd + IndirectSymbolSize;
uint64_t StringTableOffset =
SymbolTableOffset + NumSymTabSymbols * (is64Bit() ?
sizeof(MachO::nlist_64) :
sizeof(MachO::nlist));
writeSymtabLoadCommand(SymbolTableOffset, NumSymTabSymbols,
StringTableOffset, StringTable.data().size());
writeDysymtabLoadCommand(FirstLocalSymbol, NumLocalSymbols,
FirstExternalSymbol, NumExternalSymbols,
FirstUndefinedSymbol, NumUndefinedSymbols,
IndirectSymbolOffset, NumIndirectSymbols);
}
for (const auto &Option : Asm.getLinkerOptions())
writeLinkerOptionsLoadCommand(Option);
for (const MCSection &Sec : Asm) {
Asm.writeSectionData(&Sec, Layout);
uint64_t Pad = getPaddingSize(&Sec, Layout);
WriteZeros(Pad);
}
WriteZeros(SectionDataPadding);
for (const MCSection &Sec : Asm) {
std::vector<RelAndSymbol> &Relocs = Relocations[&Sec];
for (const RelAndSymbol &Rel : make_range(Relocs.rbegin(), Relocs.rend())) {
write32(Rel.MRE.r_word0);
write32(Rel.MRE.r_word1);
}
}
for (MCAssembler::const_data_region_iterator
it = Asm.data_region_begin(), ie = Asm.data_region_end();
it != ie; ++it) {
const DataRegionData *Data = &(*it);
uint64_t Start = getSymbolAddress(*Data->Start, Layout);
uint64_t End = getSymbolAddress(*Data->End, Layout);
DEBUG(dbgs() << "data in code region-- kind: " << Data->Kind
<< " start: " << Start << "(" << Data->Start->getName() << ")"
<< " end: " << End << "(" << Data->End->getName() << ")"
<< " size: " << End - Start
<< "\n");
write32(Start);
write16(End - Start);
write16(Data->Kind);
}
if (LOHSize) {
#ifndef NDEBUG
unsigned Start = getStream().tell();
#endif
Asm.getLOHContainer().emit(*this, Layout);
writeBytes("", OffsetToAlignment(LOHRawSize, is64Bit() ? 8 : 4));
assert(getStream().tell() - Start == LOHSize);
}
if (NumSymbols) {
for (MCAssembler::const_indirect_symbol_iterator
it = Asm.indirect_symbol_begin(),
ie = Asm.indirect_symbol_end(); it != ie; ++it) {
const MCSectionMachO &Section =
static_cast<const MCSectionMachO &>(*it->Section);
if (Section.getType() == MachO::S_NON_LAZY_SYMBOL_POINTERS) {
if (it->Symbol->isDefined() && !it->Symbol->isExternal()) {
uint32_t Flags = MachO::INDIRECT_SYMBOL_LOCAL;
if (it->Symbol->isAbsolute())
Flags |= MachO::INDIRECT_SYMBOL_ABS;
write32(Flags);
continue;
}
}
write32(it->Symbol->getIndex());
}
for (auto *SymbolData :
{&LocalSymbolData, &ExternalSymbolData, &UndefinedSymbolData})
for (MachSymbolData &Entry : *SymbolData)
writeNlist(Entry, Layout);
getStream() << StringTable.data();
}
}
MCObjectWriter *llvm::createMachObjectWriter(MCMachObjectTargetWriter *MOTW,
raw_pwrite_stream &OS,
bool IsLittleEndian) {
return new MachObjectWriter(MOTW, OS, IsLittleEndian);
}