MC/Mach-O: Move to MachObjectWriter.{h,cpp}.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98952 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
new file mode 100644
index 0000000..4b0077e
--- /dev/null
+++ b/lib/MC/MachObjectWriter.cpp
@@ -0,0 +1,897 @@
+//===- lib/MC/MachObjectWriter.cpp - Mach-O File Writer -------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MachObjectWriter.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MachO.h"
+#include "llvm/Target/TargetAsmBackend.h"
+
+// FIXME: Gross.
+#include "../Target/X86/X86FixupKinds.h"
+
+#include <vector>
+using namespace llvm;
+
+static unsigned getFixupKindLog2Size(unsigned Kind) {
+ switch (Kind) {
+ default: llvm_unreachable("invalid fixup kind!");
+ case X86::reloc_pcrel_1byte:
+ case FK_Data_1: return 0;
+ case FK_Data_2: return 1;
+ case X86::reloc_pcrel_4byte:
+ case X86::reloc_riprel_4byte:
+ case FK_Data_4: return 2;
+ case FK_Data_8: return 3;
+ }
+}
+
+static bool isFixupKindPCRel(unsigned Kind) {
+ switch (Kind) {
+ default:
+ return false;
+ case X86::reloc_pcrel_1byte:
+ case X86::reloc_pcrel_4byte:
+ case X86::reloc_riprel_4byte:
+ return true;
+ }
+}
+
+namespace {
+
+class MachObjectWriterImpl {
+ // See <mach-o/loader.h>.
+ enum {
+ Header_Magic32 = 0xFEEDFACE,
+ Header_Magic64 = 0xFEEDFACF
+ };
+
+ enum {
+ Header32Size = 28,
+ Header64Size = 32,
+ SegmentLoadCommand32Size = 56,
+ SegmentLoadCommand64Size = 72,
+ Section32Size = 68,
+ Section64Size = 80,
+ SymtabLoadCommandSize = 24,
+ DysymtabLoadCommandSize = 80,
+ Nlist32Size = 12,
+ Nlist64Size = 16,
+ RelocationInfoSize = 8
+ };
+
+ enum HeaderFileType {
+ HFT_Object = 0x1
+ };
+
+ enum HeaderFlags {
+ HF_SubsectionsViaSymbols = 0x2000
+ };
+
+ enum LoadCommandType {
+ LCT_Segment = 0x1,
+ LCT_Symtab = 0x2,
+ LCT_Dysymtab = 0xb,
+ LCT_Segment64 = 0x19
+ };
+
+ // See <mach-o/nlist.h>.
+ enum SymbolTypeType {
+ STT_Undefined = 0x00,
+ STT_Absolute = 0x02,
+ STT_Section = 0x0e
+ };
+
+ enum SymbolTypeFlags {
+ // If any of these bits are set, then the entry is a stab entry number (see
+ // <mach-o/stab.h>. Otherwise the other masks apply.
+ STF_StabsEntryMask = 0xe0,
+
+ STF_TypeMask = 0x0e,
+ STF_External = 0x01,
+ STF_PrivateExtern = 0x10
+ };
+
+ /// IndirectSymbolFlags - Flags for encoding special values in the indirect
+ /// symbol entry.
+ enum IndirectSymbolFlags {
+ ISF_Local = 0x80000000,
+ ISF_Absolute = 0x40000000
+ };
+
+ /// RelocationFlags - Special flags for addresses.
+ enum RelocationFlags {
+ RF_Scattered = 0x80000000
+ };
+
+ enum RelocationInfoType {
+ RIT_Vanilla = 0,
+ RIT_Pair = 1,
+ RIT_Difference = 2,
+ RIT_PreboundLazyPointer = 3,
+ RIT_LocalDifference = 4
+ };
+
+ /// MachSymbolData - Helper struct for containing some precomputed information
+ /// on symbols.
+ struct MachSymbolData {
+ MCSymbolData *SymbolData;
+ uint64_t StringIndex;
+ uint8_t SectionIndex;
+
+ // Support lexicographic sorting.
+ bool operator<(const MachSymbolData &RHS) const {
+ const std::string &Name = SymbolData->getSymbol().getName();
+ return Name < RHS.SymbolData->getSymbol().getName();
+ }
+ };
+
+ /// @name Relocation Data
+ /// @{
+
+ struct MachRelocationEntry {
+ uint32_t Word0;
+ uint32_t Word1;
+ };
+
+ llvm::DenseMap<const MCSectionData*,
+ std::vector<MachRelocationEntry> > Relocations;
+
+ /// @}
+ /// @name Symbol Table Data
+ /// @{
+
+ SmallString<256> StringTable;
+ std::vector<MachSymbolData> LocalSymbolData;
+ std::vector<MachSymbolData> ExternalSymbolData;
+ std::vector<MachSymbolData> UndefinedSymbolData;
+
+ /// @}
+
+ MachObjectWriter *Writer;
+
+ raw_ostream &OS;
+
+ unsigned Is64Bit : 1;
+
+public:
+ MachObjectWriterImpl(MachObjectWriter *_Writer, bool _Is64Bit)
+ : Writer(_Writer), OS(Writer->getStream()), Is64Bit(_Is64Bit) {
+ }
+
+ void Write8(uint8_t Value) { Writer->Write8(Value); }
+ void Write16(uint16_t Value) { Writer->Write16(Value); }
+ void Write32(uint32_t Value) { Writer->Write32(Value); }
+ void Write64(uint64_t Value) { Writer->Write64(Value); }
+ void WriteZeros(unsigned N) { Writer->WriteZeros(N); }
+ void WriteBytes(StringRef Str, unsigned ZeroFillSize = 0) {
+ Writer->WriteBytes(Str, ZeroFillSize);
+ }
+
+ void WriteHeader(unsigned NumLoadCommands, unsigned LoadCommandsSize,
+ bool SubsectionsViaSymbols) {
+ uint32_t Flags = 0;
+
+ if (SubsectionsViaSymbols)
+ Flags |= HF_SubsectionsViaSymbols;
+
+ // struct mach_header (28 bytes) or
+ // struct mach_header_64 (32 bytes)
+
+ uint64_t Start = OS.tell();
+ (void) Start;
+
+ Write32(Is64Bit ? Header_Magic64 : Header_Magic32);
+
+ // FIXME: Support cputype.
+ Write32(Is64Bit ? MachO::CPUTypeX86_64 : MachO::CPUTypeI386);
+ // FIXME: Support cpusubtype.
+ Write32(MachO::CPUSubType_I386_ALL);
+ Write32(HFT_Object);
+ Write32(NumLoadCommands); // Object files have a single load command, the
+ // segment.
+ Write32(LoadCommandsSize);
+ Write32(Flags);
+ if (Is64Bit)
+ Write32(0); // reserved
+
+ assert(OS.tell() - Start == Is64Bit ? Header64Size : Header32Size);
+ }
+
+ /// WriteSegmentLoadCommand - Write a segment load command.
+ ///
+ /// \arg NumSections - The number of sections in this segment.
+ /// \arg SectionDataSize - The total size of the sections.
+ void WriteSegmentLoadCommand(unsigned NumSections,
+ uint64_t VMSize,
+ uint64_t SectionDataStartOffset,
+ uint64_t SectionDataSize) {
+ // struct segment_command (56 bytes) or
+ // struct segment_command_64 (72 bytes)
+
+ uint64_t Start = OS.tell();
+ (void) Start;
+
+ unsigned SegmentLoadCommandSize = Is64Bit ? SegmentLoadCommand64Size :
+ SegmentLoadCommand32Size;
+ Write32(Is64Bit ? LCT_Segment64 : LCT_Segment);
+ Write32(SegmentLoadCommandSize +
+ NumSections * (Is64Bit ? Section64Size : Section32Size));
+
+ WriteBytes("", 16);
+ if (Is64Bit) {
+ Write64(0); // vmaddr
+ Write64(VMSize); // vmsize
+ Write64(SectionDataStartOffset); // file offset
+ Write64(SectionDataSize); // file size
+ } else {
+ Write32(0); // vmaddr
+ Write32(VMSize); // vmsize
+ Write32(SectionDataStartOffset); // file offset
+ Write32(SectionDataSize); // file size
+ }
+ Write32(0x7); // maxprot
+ Write32(0x7); // initprot
+ Write32(NumSections);
+ Write32(0); // flags
+
+ assert(OS.tell() - Start == SegmentLoadCommandSize);
+ }
+
+ void WriteSection(const MCAssembler &Asm, const MCSectionData &SD,
+ uint64_t FileOffset, uint64_t RelocationsStart,
+ unsigned NumRelocations) {
+ // The offset is unused for virtual sections.
+ if (Asm.getBackend().isVirtualSection(SD.getSection())) {
+ assert(SD.getFileSize() == 0 && "Invalid file size!");
+ FileOffset = 0;
+ }
+
+ // struct section (68 bytes) or
+ // struct section_64 (80 bytes)
+
+ uint64_t Start = OS.tell();
+ (void) Start;
+
+ // FIXME: cast<> support!
+ const MCSectionMachO &Section =
+ static_cast<const MCSectionMachO&>(SD.getSection());
+ WriteBytes(Section.getSectionName(), 16);
+ WriteBytes(Section.getSegmentName(), 16);
+ if (Is64Bit) {
+ Write64(SD.getAddress()); // address
+ Write64(SD.getSize()); // size
+ } else {
+ Write32(SD.getAddress()); // address
+ Write32(SD.getSize()); // size
+ }
+ Write32(FileOffset);
+
+ unsigned Flags = Section.getTypeAndAttributes();
+ if (SD.hasInstructions())
+ Flags |= MCSectionMachO::S_ATTR_SOME_INSTRUCTIONS;
+
+ assert(isPowerOf2_32(SD.getAlignment()) && "Invalid alignment!");
+ Write32(Log2_32(SD.getAlignment()));
+ Write32(NumRelocations ? RelocationsStart : 0);
+ Write32(NumRelocations);
+ Write32(Flags);
+ Write32(0); // reserved1
+ Write32(Section.getStubSize()); // reserved2
+ if (Is64Bit)
+ Write32(0); // reserved3
+
+ assert(OS.tell() - Start == Is64Bit ? Section64Size : Section32Size);
+ }
+
+ void WriteSymtabLoadCommand(uint32_t SymbolOffset, uint32_t NumSymbols,
+ uint32_t StringTableOffset,
+ uint32_t StringTableSize) {
+ // struct symtab_command (24 bytes)
+
+ uint64_t Start = OS.tell();
+ (void) Start;
+
+ Write32(LCT_Symtab);
+ Write32(SymtabLoadCommandSize);
+ Write32(SymbolOffset);
+ Write32(NumSymbols);
+ Write32(StringTableOffset);
+ Write32(StringTableSize);
+
+ assert(OS.tell() - Start == SymtabLoadCommandSize);
+ }
+
+ void 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) {
+ // struct dysymtab_command (80 bytes)
+
+ uint64_t Start = OS.tell();
+ (void) Start;
+
+ Write32(LCT_Dysymtab);
+ Write32(DysymtabLoadCommandSize);
+ Write32(FirstLocalSymbol);
+ Write32(NumLocalSymbols);
+ Write32(FirstExternalSymbol);
+ Write32(NumExternalSymbols);
+ Write32(FirstUndefinedSymbol);
+ Write32(NumUndefinedSymbols);
+ Write32(0); // tocoff
+ Write32(0); // ntoc
+ Write32(0); // modtaboff
+ Write32(0); // nmodtab
+ Write32(0); // extrefsymoff
+ Write32(0); // nextrefsyms
+ Write32(IndirectSymbolOffset);
+ Write32(NumIndirectSymbols);
+ Write32(0); // extreloff
+ Write32(0); // nextrel
+ Write32(0); // locreloff
+ Write32(0); // nlocrel
+
+ assert(OS.tell() - Start == DysymtabLoadCommandSize);
+ }
+
+ void WriteNlist(MachSymbolData &MSD) {
+ MCSymbolData &Data = *MSD.SymbolData;
+ const MCSymbol &Symbol = Data.getSymbol();
+ uint8_t Type = 0;
+ uint16_t Flags = Data.getFlags();
+ uint32_t Address = 0;
+
+ // Set the N_TYPE bits. See <mach-o/nlist.h>.
+ //
+ // FIXME: Are the prebound or indirect fields possible here?
+ if (Symbol.isUndefined())
+ Type = STT_Undefined;
+ else if (Symbol.isAbsolute())
+ Type = STT_Absolute;
+ else
+ Type = STT_Section;
+
+ // FIXME: Set STAB bits.
+
+ if (Data.isPrivateExtern())
+ Type |= STF_PrivateExtern;
+
+ // Set external bit.
+ if (Data.isExternal() || Symbol.isUndefined())
+ Type |= STF_External;
+
+ // Compute the symbol address.
+ if (Symbol.isDefined()) {
+ if (Symbol.isAbsolute()) {
+ llvm_unreachable("FIXME: Not yet implemented!");
+ } else {
+ Address = Data.getAddress();
+ }
+ } else if (Data.isCommon()) {
+ // Common symbols are encoded with the size in the address
+ // field, and their alignment in the flags.
+ Address = Data.getCommonSize();
+
+ // Common alignment is packed into the 'desc' bits.
+ if (unsigned Align = Data.getCommonAlignment()) {
+ unsigned Log2Size = Log2_32(Align);
+ assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
+ if (Log2Size > 15)
+ llvm_report_error("invalid 'common' alignment '" +
+ Twine(Align) + "'");
+ // FIXME: Keep this mask with the SymbolFlags enumeration.
+ Flags = (Flags & 0xF0FF) | (Log2Size << 8);
+ }
+ }
+
+ // struct nlist (12 bytes)
+
+ Write32(MSD.StringIndex);
+ Write8(Type);
+ Write8(MSD.SectionIndex);
+
+ // The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
+ // value.
+ Write16(Flags);
+ if (Is64Bit)
+ Write64(Address);
+ else
+ Write32(Address);
+ }
+
+ void RecordScatteredRelocation(const MCAssembler &Asm,
+ const MCFragment &Fragment,
+ const MCAsmFixup &Fixup, MCValue Target,
+ uint64_t &FixedValue) {
+ uint32_t Address = Fragment.getOffset() + Fixup.Offset;
+ unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
+ unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
+ unsigned Type = RIT_Vanilla;
+
+ // See <reloc.h>.
+ const MCSymbol *A = &Target.getSymA()->getSymbol();
+ MCSymbolData *A_SD = &Asm.getSymbolData(*A);
+
+ if (!A_SD->getFragment())
+ llvm_report_error("symbol '" + A->getName() +
+ "' can not be undefined in a subtraction expression");
+
+ uint32_t Value = A_SD->getAddress();
+ uint32_t Value2 = 0;
+
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ MCSymbolData *B_SD = &Asm.getSymbolData(B->getSymbol());
+
+ if (!B_SD->getFragment())
+ llvm_report_error("symbol '" + B->getSymbol().getName() +
+ "' can not be undefined in a subtraction expression");
+
+ // Select the appropriate difference relocation type.
+ //
+ // Note that there is no longer any semantic difference between these two
+ // relocation types from the linkers point of view, this is done solely
+ // for pedantic compatibility with 'as'.
+ Type = A_SD->isExternal() ? RIT_Difference : RIT_LocalDifference;
+ Value2 = B_SD->getAddress();
+ }
+
+ // Relocations are written out in reverse order, so the PAIR comes first.
+ if (Type == RIT_Difference || Type == RIT_LocalDifference) {
+ MachRelocationEntry MRE;
+ MRE.Word0 = ((0 << 0) |
+ (RIT_Pair << 24) |
+ (Log2Size << 28) |
+ (IsPCRel << 30) |
+ RF_Scattered);
+ MRE.Word1 = Value2;
+ Relocations[Fragment.getParent()].push_back(MRE);
+ }
+
+ MachRelocationEntry MRE;
+ MRE.Word0 = ((Address << 0) |
+ (Type << 24) |
+ (Log2Size << 28) |
+ (IsPCRel << 30) |
+ RF_Scattered);
+ MRE.Word1 = Value;
+ Relocations[Fragment.getParent()].push_back(MRE);
+ }
+
+ virtual void RecordRelocation(const MCAssembler &Asm,
+ const MCDataFragment &Fragment,
+ const MCAsmFixup &Fixup, MCValue Target,
+ uint64_t &FixedValue) {
+ unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
+ unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
+
+ // If this is a difference or a defined symbol plus an offset, then we need
+ // a scattered relocation entry.
+ uint32_t Offset = Target.getConstant();
+ if (IsPCRel)
+ Offset += 1 << Log2Size;
+ if (Target.getSymB() ||
+ (Target.getSymA() && !Target.getSymA()->getSymbol().isUndefined() &&
+ Offset)) {
+ RecordScatteredRelocation(Asm, Fragment, Fixup, Target, FixedValue);
+ return;
+ }
+
+ // See <reloc.h>.
+ uint32_t Address = Fragment.getOffset() + Fixup.Offset;
+ uint32_t Value = 0;
+ unsigned Index = 0;
+ unsigned IsExtern = 0;
+ unsigned Type = 0;
+
+ if (Target.isAbsolute()) { // constant
+ // SymbolNum of 0 indicates the absolute section.
+ //
+ // FIXME: Currently, these are never generated (see code below). I cannot
+ // find a case where they are actually emitted.
+ Type = RIT_Vanilla;
+ Value = 0;
+ } else {
+ const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
+ MCSymbolData *SD = &Asm.getSymbolData(*Symbol);
+
+ if (Symbol->isUndefined()) {
+ IsExtern = 1;
+ Index = SD->getIndex();
+ Value = 0;
+ } else {
+ // The index is the section ordinal.
+ //
+ // FIXME: O(N)
+ Index = 1;
+ MCAssembler::const_iterator it = Asm.begin(), ie = Asm.end();
+ for (; it != ie; ++it, ++Index)
+ if (&*it == SD->getFragment()->getParent())
+ break;
+ assert(it != ie && "Unable to find section index!");
+ Value = SD->getAddress();
+ }
+
+ Type = RIT_Vanilla;
+ }
+
+ // struct relocation_info (8 bytes)
+ MachRelocationEntry MRE;
+ MRE.Word0 = Address;
+ MRE.Word1 = ((Index << 0) |
+ (IsPCRel << 24) |
+ (Log2Size << 25) |
+ (IsExtern << 27) |
+ (Type << 28));
+ Relocations[Fragment.getParent()].push_back(MRE);
+ }
+
+ void BindIndirectSymbols(MCAssembler &Asm) {
+ // This is the point where 'as' creates actual symbols for indirect symbols
+ // (in the following two passes). It would be easier for us to do this
+ // sooner when we see the attribute, but that makes getting the order in the
+ // symbol table much more complicated than it is worth.
+ //
+ // FIXME: Revisit this when the dust settles.
+
+ // Bind non lazy symbol pointers first.
+ for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
+ ie = Asm.indirect_symbol_end(); it != ie; ++it) {
+ // FIXME: cast<> support!
+ const MCSectionMachO &Section =
+ static_cast<const MCSectionMachO&>(it->SectionData->getSection());
+
+ if (Section.getType() != MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS)
+ continue;
+
+ Asm.getOrCreateSymbolData(*it->Symbol);
+ }
+
+ // Then lazy symbol pointers and symbol stubs.
+ for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
+ ie = Asm.indirect_symbol_end(); it != ie; ++it) {
+ // FIXME: cast<> support!
+ const MCSectionMachO &Section =
+ static_cast<const MCSectionMachO&>(it->SectionData->getSection());
+
+ if (Section.getType() != MCSectionMachO::S_LAZY_SYMBOL_POINTERS &&
+ Section.getType() != MCSectionMachO::S_SYMBOL_STUBS)
+ continue;
+
+ // Set the symbol type to undefined lazy, but only on construction.
+ //
+ // FIXME: Do not hardcode.
+ bool Created;
+ MCSymbolData &Entry = Asm.getOrCreateSymbolData(*it->Symbol, &Created);
+ if (Created)
+ Entry.setFlags(Entry.getFlags() | 0x0001);
+ }
+ }
+
+ /// ComputeSymbolTable - Compute the symbol table data
+ ///
+ /// \param StringTable [out] - The string table data.
+ /// \param StringIndexMap [out] - Map from symbol names to offsets in the
+ /// string table.
+ void ComputeSymbolTable(MCAssembler &Asm, SmallString<256> &StringTable,
+ std::vector<MachSymbolData> &LocalSymbolData,
+ std::vector<MachSymbolData> &ExternalSymbolData,
+ std::vector<MachSymbolData> &UndefinedSymbolData) {
+ // Build section lookup table.
+ DenseMap<const MCSection*, uint8_t> SectionIndexMap;
+ unsigned Index = 1;
+ for (MCAssembler::iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it, ++Index)
+ SectionIndexMap[&it->getSection()] = Index;
+ assert(Index <= 256 && "Too many sections!");
+
+ // Index 0 is always the empty string.
+ StringMap<uint64_t> StringIndexMap;
+ StringTable += '\x00';
+
+ // Build the symbol arrays and the string table, but only for non-local
+ // symbols.
+ //
+ // The particular order that we collect the symbols and create the string
+ // table, then sort the symbols is chosen to match 'as'. Even though it
+ // doesn't matter for correctness, this is important for letting us diff .o
+ // files.
+ for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
+ ie = Asm.symbol_end(); it != ie; ++it) {
+ const MCSymbol &Symbol = it->getSymbol();
+
+ // Ignore non-linker visible symbols.
+ if (!Asm.isSymbolLinkerVisible(it))
+ continue;
+
+ if (!it->isExternal() && !Symbol.isUndefined())
+ continue;
+
+ uint64_t &Entry = StringIndexMap[Symbol.getName()];
+ if (!Entry) {
+ Entry = StringTable.size();
+ StringTable += Symbol.getName();
+ StringTable += '\x00';
+ }
+
+ MachSymbolData MSD;
+ MSD.SymbolData = it;
+ MSD.StringIndex = Entry;
+
+ 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);
+ }
+ }
+
+ // Now add the data for local symbols.
+ for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
+ ie = Asm.symbol_end(); it != ie; ++it) {
+ const MCSymbol &Symbol = it->getSymbol();
+
+ // Ignore non-linker visible symbols.
+ if (!Asm.isSymbolLinkerVisible(it))
+ continue;
+
+ if (it->isExternal() || Symbol.isUndefined())
+ continue;
+
+ uint64_t &Entry = StringIndexMap[Symbol.getName()];
+ if (!Entry) {
+ Entry = StringTable.size();
+ StringTable += Symbol.getName();
+ StringTable += '\x00';
+ }
+
+ MachSymbolData MSD;
+ MSD.SymbolData = it;
+ MSD.StringIndex = Entry;
+
+ 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);
+ }
+ }
+
+ // External and undefined symbols are required to be in lexicographic order.
+ std::sort(ExternalSymbolData.begin(), ExternalSymbolData.end());
+ std::sort(UndefinedSymbolData.begin(), UndefinedSymbolData.end());
+
+ // Set the symbol indices.
+ Index = 0;
+ for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
+ LocalSymbolData[i].SymbolData->setIndex(Index++);
+ for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
+ ExternalSymbolData[i].SymbolData->setIndex(Index++);
+ for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
+ UndefinedSymbolData[i].SymbolData->setIndex(Index++);
+
+ // The string table is padded to a multiple of 4.
+ while (StringTable.size() % 4)
+ StringTable += '\x00';
+ }
+
+ virtual void ExecutePostLayoutBinding(MCAssembler &Asm) {
+ // Create symbol data for any indirect symbols.
+ BindIndirectSymbols(Asm);
+
+ // Compute symbol table information and bind symbol indices.
+ ComputeSymbolTable(Asm, StringTable, LocalSymbolData, ExternalSymbolData,
+ UndefinedSymbolData);
+ }
+
+ virtual void WriteObject(const MCAssembler &Asm) {
+ unsigned NumSections = Asm.size();
+
+ // The section data starts after the header, the segment load command (and
+ // section headers) and the symbol table.
+ unsigned NumLoadCommands = 1;
+ uint64_t LoadCommandsSize = Is64Bit ?
+ SegmentLoadCommand64Size + NumSections * Section64Size :
+ SegmentLoadCommand32Size + NumSections * Section32Size;
+
+ // Add the symbol table load command sizes, if used.
+ unsigned NumSymbols = LocalSymbolData.size() + ExternalSymbolData.size() +
+ UndefinedSymbolData.size();
+ if (NumSymbols) {
+ NumLoadCommands += 2;
+ LoadCommandsSize += SymtabLoadCommandSize + DysymtabLoadCommandSize;
+ }
+
+ // Compute the total size of the section data, as well as its file size and
+ // vm size.
+ uint64_t SectionDataStart = (Is64Bit ? Header64Size : Header32Size)
+ + LoadCommandsSize;
+ uint64_t SectionDataSize = 0;
+ uint64_t SectionDataFileSize = 0;
+ uint64_t VMSize = 0;
+ for (MCAssembler::const_iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ const MCSectionData &SD = *it;
+
+ VMSize = std::max(VMSize, SD.getAddress() + SD.getSize());
+
+ if (Asm.getBackend().isVirtualSection(SD.getSection()))
+ continue;
+
+ SectionDataSize = std::max(SectionDataSize,
+ SD.getAddress() + SD.getSize());
+ SectionDataFileSize = std::max(SectionDataFileSize,
+ SD.getAddress() + SD.getFileSize());
+ }
+
+ // The section data is padded to 4 bytes.
+ //
+ // FIXME: Is this machine dependent?
+ unsigned SectionDataPadding = OffsetToAlignment(SectionDataFileSize, 4);
+ SectionDataFileSize += SectionDataPadding;
+
+ // Write the prolog, starting with the header and load command...
+ WriteHeader(NumLoadCommands, LoadCommandsSize,
+ Asm.getSubsectionsViaSymbols());
+ WriteSegmentLoadCommand(NumSections, VMSize,
+ SectionDataStart, SectionDataSize);
+
+ // ... and then the section headers.
+ uint64_t RelocTableEnd = SectionDataStart + SectionDataFileSize;
+ for (MCAssembler::const_iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ std::vector<MachRelocationEntry> &Relocs = Relocations[it];
+ unsigned NumRelocs = Relocs.size();
+ uint64_t SectionStart = SectionDataStart + it->getAddress();
+ WriteSection(Asm, *it, SectionStart, RelocTableEnd, NumRelocs);
+ RelocTableEnd += NumRelocs * RelocationInfoSize;
+ }
+
+ // Write the symbol table load command, if used.
+ 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 used, the indirect symbols are written after the section data.
+ if (NumIndirectSymbols)
+ IndirectSymbolOffset = RelocTableEnd;
+
+ // The symbol table is written after the indirect symbol data.
+ uint64_t SymbolTableOffset = RelocTableEnd + IndirectSymbolSize;
+
+ // The string table is written after symbol table.
+ uint64_t StringTableOffset =
+ SymbolTableOffset + NumSymTabSymbols * (Is64Bit ? Nlist64Size :
+ Nlist32Size);
+ WriteSymtabLoadCommand(SymbolTableOffset, NumSymTabSymbols,
+ StringTableOffset, StringTable.size());
+
+ WriteDysymtabLoadCommand(FirstLocalSymbol, NumLocalSymbols,
+ FirstExternalSymbol, NumExternalSymbols,
+ FirstUndefinedSymbol, NumUndefinedSymbols,
+ IndirectSymbolOffset, NumIndirectSymbols);
+ }
+
+ // Write the actual section data.
+ for (MCAssembler::const_iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it)
+ Asm.WriteSectionData(it, Writer);
+
+ // Write the extra padding.
+ WriteZeros(SectionDataPadding);
+
+ // Write the relocation entries.
+ for (MCAssembler::const_iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ // Write the section relocation entries, in reverse order to match 'as'
+ // (approximately, the exact algorithm is more complicated than this).
+ std::vector<MachRelocationEntry> &Relocs = Relocations[it];
+ for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
+ Write32(Relocs[e - i - 1].Word0);
+ Write32(Relocs[e - i - 1].Word1);
+ }
+ }
+
+ // Write the symbol table data, if used.
+ if (NumSymbols) {
+ // Write the indirect symbol entries.
+ for (MCAssembler::const_indirect_symbol_iterator
+ it = Asm.indirect_symbol_begin(),
+ ie = Asm.indirect_symbol_end(); it != ie; ++it) {
+ // Indirect symbols in the non lazy symbol pointer section have some
+ // special handling.
+ const MCSectionMachO &Section =
+ static_cast<const MCSectionMachO&>(it->SectionData->getSection());
+ if (Section.getType() == MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS) {
+ // If this symbol is defined and internal, mark it as such.
+ if (it->Symbol->isDefined() &&
+ !Asm.getSymbolData(*it->Symbol).isExternal()) {
+ uint32_t Flags = ISF_Local;
+ if (it->Symbol->isAbsolute())
+ Flags |= ISF_Absolute;
+ Write32(Flags);
+ continue;
+ }
+ }
+
+ Write32(Asm.getSymbolData(*it->Symbol).getIndex());
+ }
+
+ // FIXME: Check that offsets match computed ones.
+
+ // Write the symbol table entries.
+ for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
+ WriteNlist(LocalSymbolData[i]);
+ for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
+ WriteNlist(ExternalSymbolData[i]);
+ for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
+ WriteNlist(UndefinedSymbolData[i]);
+
+ // Write the string table.
+ OS << StringTable.str();
+ }
+ }
+};
+
+}
+
+MachObjectWriter::MachObjectWriter(raw_ostream &OS,
+ bool Is64Bit,
+ bool IsLittleEndian)
+ : MCObjectWriter(OS, IsLittleEndian)
+{
+ Impl = new MachObjectWriterImpl(this, Is64Bit);
+}
+
+MachObjectWriter::~MachObjectWriter() {
+ delete (MachObjectWriterImpl*) Impl;
+}
+
+void MachObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm) {
+ ((MachObjectWriterImpl*) Impl)->ExecutePostLayoutBinding(Asm);
+}
+
+void MachObjectWriter::RecordRelocation(const MCAssembler &Asm,
+ const MCDataFragment &Fragment,
+ const MCAsmFixup &Fixup, MCValue Target,
+ uint64_t &FixedValue) {
+ ((MachObjectWriterImpl*) Impl)->RecordRelocation(Asm, Fragment, Fixup,
+ Target, FixedValue);
+}
+
+void MachObjectWriter::WriteObject(const MCAssembler &Asm) {
+ ((MachObjectWriterImpl*) Impl)->WriteObject(Asm);
+}