blob: 12a7f0ee7bb5a8dfc6fa8ceb9ef593191ec408a6 [file] [log] [blame]
//===-- llvm/MC/MCMachObjectWriter.h - Mach Object Writer -------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/MachO.h"
#include <vector>
namespace llvm {
class MCSectionData;
class MachObjectWriter;
class MCMachObjectTargetWriter {
const unsigned Is64Bit : 1;
const uint32_t CPUType;
const uint32_t CPUSubtype;
// FIXME: Remove this, we should just always use it once we no longer care
// about Darwin 'as' compatibility.
const unsigned UseAggressiveSymbolFolding : 1;
unsigned LocalDifference_RIT;
MCMachObjectTargetWriter(bool Is64Bit_, uint32_t CPUType_,
uint32_t CPUSubtype_,
bool UseAggressiveSymbolFolding_ = false);
void setLocalDifferenceRelocationType(unsigned Type) {
LocalDifference_RIT = Type;
virtual ~MCMachObjectTargetWriter();
/// @name Lifetime Management
/// @{
virtual void reset() {};
/// @}
/// @name Accessors
/// @{
bool is64Bit() const { return Is64Bit; }
bool useAggressiveSymbolFolding() const { return UseAggressiveSymbolFolding; }
uint32_t getCPUType() const { return CPUType; }
uint32_t getCPUSubtype() const { return CPUSubtype; }
unsigned getLocalDifferenceRelocationType() const {
return LocalDifference_RIT;
/// @}
/// @name API
/// @{
virtual void RecordRelocation(MachObjectWriter *Writer,
const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup,
MCValue Target,
uint64_t &FixedValue) = 0;
/// @}
class MachObjectWriter : public MCObjectWriter {
/// 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;
/// The target specific Mach-O writer instance.
std::unique_ptr<MCMachObjectTargetWriter> TargetObjectWriter;
/// @name Relocation Data
/// @{
llvm::DenseMap<const MCSectionData*,
std::vector<MachO::any_relocation_info> > Relocations;
llvm::DenseMap<const MCSectionData*, unsigned> IndirectSymBase;
/// @}
/// @name Symbol Table Data
/// @{
SmallString<256> StringTable;
std::vector<MachSymbolData> LocalSymbolData;
std::vector<MachSymbolData> ExternalSymbolData;
std::vector<MachSymbolData> UndefinedSymbolData;
/// @}
MachSymbolData *findSymbolData(const MCSymbol &Sym);
MachObjectWriter(MCMachObjectTargetWriter *MOTW, raw_ostream &_OS,
bool _IsLittleEndian)
: MCObjectWriter(_OS, _IsLittleEndian), TargetObjectWriter(MOTW) {
/// @name Lifetime management Methods
/// @{
void reset() override;
/// @}
/// @name Utility Methods
/// @{
bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind);
SectionAddrMap SectionAddress;
SectionAddrMap &getSectionAddressMap() { return SectionAddress; }
uint64_t getSectionAddress(const MCSectionData* SD) const {
return SectionAddress.lookup(SD);
uint64_t getSymbolAddress(const MCSymbolData* SD,
const MCAsmLayout &Layout) const;
uint64_t getFragmentAddress(const MCFragment *Fragment,
const MCAsmLayout &Layout) const;
uint64_t getPaddingSize(const MCSectionData *SD,
const MCAsmLayout &Layout) const;
bool doesSymbolRequireExternRelocation(const MCSymbolData *SD);
/// @}
/// @name Target Writer Proxy Accessors
/// @{
bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
bool isX86_64() const {
uint32_t CPUType = TargetObjectWriter->getCPUType();
return CPUType == MachO::CPU_TYPE_X86_64;
/// @}
void WriteHeader(unsigned NumLoadCommands, unsigned LoadCommandsSize,
bool SubsectionsViaSymbols);
/// WriteSegmentLoadCommand - Write a segment load command.
/// \param NumSections The number of sections in this segment.
/// \param SectionDataSize The total size of the sections.
void WriteSegmentLoadCommand(unsigned NumSections,
uint64_t VMSize,
uint64_t SectionDataStartOffset,
uint64_t SectionDataSize);
void WriteSection(const MCAssembler &Asm, const MCAsmLayout &Layout,
const MCSectionData &SD, uint64_t FileOffset,
uint64_t RelocationsStart, unsigned NumRelocations);
void WriteSymtabLoadCommand(uint32_t SymbolOffset, uint32_t NumSymbols,
uint32_t StringTableOffset,
uint32_t StringTableSize);
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);
void WriteNlist(MachSymbolData &MSD, const MCAsmLayout &Layout);
void WriteLinkeditLoadCommand(uint32_t Type, uint32_t DataOffset,
uint32_t DataSize);
void WriteLinkerOptionsLoadCommand(const std::vector<std::string> &Options);
// FIXME: We really need to improve the relocation validation. Basically, we
// want to implement a separate computation which evaluates the relocation
// entry as the linker would, and verifies that the resultant fixup value is
// exactly what the encoder wanted. This will catch several classes of
// problems:
// - Relocation entry bugs, the two algorithms are unlikely to have the same
// exact bug.
// - Relaxation issues, where we forget to relax something.
// - Input errors, where something cannot be correctly encoded. 'as' allows
// these through in many cases.
void addRelocation(const MCSectionData *SD,
MachO::any_relocation_info &MRE) {
void RecordScatteredRelocation(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
unsigned Log2Size,
uint64_t &FixedValue);
void RecordTLVPRelocation(const MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
const MCFixup &Fixup, MCValue Target,
uint64_t &FixedValue);
void RecordRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
const MCFragment *Fragment, const MCFixup &Fixup,
MCValue Target, bool &IsPCRel,
uint64_t &FixedValue) override;
void BindIndirectSymbols(MCAssembler &Asm);
/// ComputeSymbolTable - Compute the symbol table data
/// \param StringTable [out] - The string table data.
void ComputeSymbolTable(MCAssembler &Asm, SmallString<256> &StringTable,
std::vector<MachSymbolData> &LocalSymbolData,
std::vector<MachSymbolData> &ExternalSymbolData,
std::vector<MachSymbolData> &UndefinedSymbolData);
void computeSectionAddresses(const MCAssembler &Asm,
const MCAsmLayout &Layout);
void markAbsoluteVariableSymbols(MCAssembler &Asm,
const MCAsmLayout &Layout);
void ExecutePostLayoutBinding(MCAssembler &Asm,
const MCAsmLayout &Layout) override;
bool IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
const MCSymbolData &DataA,
const MCFragment &FB,
bool InSet,
bool IsPCRel) const override;
void WriteObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
/// \brief Construct a new Mach-O writer instance.
/// This routine takes ownership of the target writer subclass.
/// \param MOTW - The target specific Mach-O writer subclass.
/// \param OS - The stream to write to.
/// \returns The constructed object writer.
MCObjectWriter *createMachObjectWriter(MCMachObjectTargetWriter *MOTW,
raw_ostream &OS, bool IsLittleEndian);
} // End llvm namespace