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Diffstat (limited to 'contrib/llvm-project/llvm/include/llvm/MC/MCMachObjectWriter.h')
| -rw-r--r-- | contrib/llvm-project/llvm/include/llvm/MC/MCMachObjectWriter.h | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/include/llvm/MC/MCMachObjectWriter.h b/contrib/llvm-project/llvm/include/llvm/MC/MCMachObjectWriter.h new file mode 100644 index 000000000000..278aebee99ac --- /dev/null +++ b/contrib/llvm-project/llvm/include/llvm/MC/MCMachObjectWriter.h @@ -0,0 +1,287 @@ +//===- llvm/MC/MCMachObjectWriter.h - Mach Object Writer --------*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_MC_MCMACHOBJECTWRITER_H +#define LLVM_MC_MCMACHOBJECTWRITER_H + +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/StringRef.h" +#include "llvm/BinaryFormat/MachO.h" +#include "llvm/MC/MCExpr.h" +#include "llvm/MC/MCObjectWriter.h" +#include "llvm/MC/MCSection.h" +#include "llvm/MC/StringTableBuilder.h" +#include <cstdint> +#include <memory> +#include <string> +#include <vector> + +namespace llvm { + +class MachObjectWriter; + +class MCMachObjectTargetWriter : public MCObjectTargetWriter { + const unsigned Is64Bit : 1; + const uint32_t CPUType; + const uint32_t CPUSubtype; + unsigned LocalDifference_RIT; + +protected: + MCMachObjectTargetWriter(bool Is64Bit_, uint32_t CPUType_, + uint32_t CPUSubtype_); + + void setLocalDifferenceRelocationType(unsigned Type) { + LocalDifference_RIT = Type; + } + +public: + virtual ~MCMachObjectTargetWriter(); + + virtual Triple::ObjectFormatType getFormat() const { return Triple::MachO; } + static bool classof(const MCObjectTargetWriter *W) { + return W->getFormat() == Triple::MachO; + } + + /// \name Lifetime Management + /// @{ + + virtual void reset() {} + + /// @} + + /// \name Accessors + /// @{ + + bool is64Bit() const { return Is64Bit; } + 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, MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCFragment *Fragment, + const MCFixup &Fixup, MCValue Target, + uint64_t &FixedValue) = 0; + + /// @} +}; + +class MachObjectWriter : public MCObjectWriter { + /// Helper struct for containing some precomputed information on symbols. + struct MachSymbolData { + const MCSymbol *Symbol; + 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 + /// @{ + + struct RelAndSymbol { + const MCSymbol *Sym; + MachO::any_relocation_info MRE; + RelAndSymbol(const MCSymbol *Sym, const MachO::any_relocation_info &MRE) + : Sym(Sym), MRE(MRE) {} + }; + + DenseMap<const MCSection *, std::vector<RelAndSymbol>> Relocations; + DenseMap<const MCSection *, unsigned> IndirectSymBase; + + SectionAddrMap SectionAddress; + + /// @} + /// \name Symbol Table Data + /// @{ + + StringTableBuilder StringTable{StringTableBuilder::MachO}; + std::vector<MachSymbolData> LocalSymbolData; + std::vector<MachSymbolData> ExternalSymbolData; + std::vector<MachSymbolData> UndefinedSymbolData; + + /// @} + + MachSymbolData *findSymbolData(const MCSymbol &Sym); + + void writeWithPadding(StringRef Str, uint64_t Size); + +public: + MachObjectWriter(std::unique_ptr<MCMachObjectTargetWriter> MOTW, + raw_pwrite_stream &OS, bool IsLittleEndian) + : TargetObjectWriter(std::move(MOTW)), + W(OS, IsLittleEndian ? support::little : support::big) {} + + support::endian::Writer W; + + const MCSymbol &findAliasedSymbol(const MCSymbol &Sym) const; + + /// \name Lifetime management Methods + /// @{ + + void reset() override; + + /// @} + + /// \name Utility Methods + /// @{ + + bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind); + + SectionAddrMap &getSectionAddressMap() { return SectionAddress; } + + uint64_t getSectionAddress(const MCSection *Sec) const { + return SectionAddress.lookup(Sec); + } + uint64_t getSymbolAddress(const MCSymbol &S, const MCAsmLayout &Layout) const; + + uint64_t getFragmentAddress(const MCFragment *Fragment, + const MCAsmLayout &Layout) const; + + uint64_t getPaddingSize(const MCSection *SD, const MCAsmLayout &Layout) const; + + bool doesSymbolRequireExternRelocation(const MCSymbol &S); + + /// @} + + /// \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(MachO::HeaderFileType Type, unsigned NumLoadCommands, + unsigned LoadCommandsSize, bool SubsectionsViaSymbols); + + /// Write a segment load command. + /// + /// \param NumSections The number of sections in this segment. + /// \param SectionDataSize The total size of the sections. + void writeSegmentLoadCommand(StringRef Name, unsigned NumSections, + uint64_t VMAddr, uint64_t VMSize, + uint64_t SectionDataStartOffset, + uint64_t SectionDataSize, uint32_t MaxProt, + uint32_t InitProt); + + void writeSection(const MCAsmLayout &Layout, const MCSection &Sec, + uint64_t VMAddr, uint64_t FileOffset, unsigned Flags, + 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. + + // Add a relocation to be output in the object file. At the time this is + // called, the symbol indexes are not know, so if the relocation refers + // to a symbol it should be passed as \p RelSymbol so that it can be updated + // afterwards. If the relocation doesn't refer to a symbol, nullptr should be + // used. + void addRelocation(const MCSymbol *RelSymbol, const MCSection *Sec, + MachO::any_relocation_info &MRE) { + RelAndSymbol P(RelSymbol, MRE); + Relocations[Sec].push_back(P); + } + + 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(MCAssembler &Asm, const MCAsmLayout &Layout, + const MCFragment *Fragment, const MCFixup &Fixup, + MCValue Target, uint64_t &FixedValue) override; + + void bindIndirectSymbols(MCAssembler &Asm); + + /// Compute the symbol table data. + void computeSymbolTable(MCAssembler &Asm, + std::vector<MachSymbolData> &LocalSymbolData, + std::vector<MachSymbolData> &ExternalSymbolData, + std::vector<MachSymbolData> &UndefinedSymbolData); + + void computeSectionAddresses(const MCAssembler &Asm, + const MCAsmLayout &Layout); + + void executePostLayoutBinding(MCAssembler &Asm, + const MCAsmLayout &Layout) override; + + bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm, + const MCSymbol &A, + const MCSymbol &B, + bool InSet) const override; + + bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm, + const MCSymbol &SymA, + const MCFragment &FB, bool InSet, + bool IsPCRel) const override; + + uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override; +}; + +/// 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. +std::unique_ptr<MCObjectWriter> +createMachObjectWriter(std::unique_ptr<MCMachObjectTargetWriter> MOTW, + raw_pwrite_stream &OS, bool IsLittleEndian); + +} // end namespace llvm + +#endif // LLVM_MC_MCMACHOBJECTWRITER_H |