Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- llvm/MC/MCELFObjectWriter.h - ELF 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_MCELFOBJECTWRITER_H

#define LLVM_MC_MCELFOBJECTWRITER_H

#include "llvm/ADT/Triple.h"

#include "llvm/BinaryFormat/ELF.h"

#include "llvm/MC/MCObjectWriter.h"

#include "llvm/MC/MCSectionELF.h"

#include "llvm/Support/Casting.h"

#include "llvm/Support/raw_ostream.h"

#include <cstdint>

#include <vector>

namespace llvm {

class MCAssembler;

class MCContext;

class MCFixup;

class MCSymbol;

class MCSymbolELF;

class MCValue;

struct ELFRelocationEntry {

  uint64_t Offset; // Where is the relocation.

  const MCSymbolELF *Symbol; // The symbol to relocate with.

  unsigned Type;   // The type of the relocation.

  uint64_t Addend; // The addend to use.

  const MCSymbolELF *OriginalSymbol; // The original value of Symbol if we changed it.

  uint64_t OriginalAddend; // The original value of addend.

  ELFRelocationEntry(uint64_t Offset, const MCSymbolELF *Symbol, unsigned Type,

                     uint64_t Addend, const MCSymbolELF *OriginalSymbol,

                     uint64_t OriginalAddend)

      : Offset(Offset), Symbol(Symbol), Type(Type), Addend(Addend),

        OriginalSymbol(OriginalSymbol), OriginalAddend(OriginalAddend) {}

  void print(raw_ostream &Out) const {

    Out << "Off=" << Offset << ", Sym=" << Symbol << ", Type=" << Type

        << ", Addend=" << Addend << ", OriginalSymbol=" << OriginalSymbol

        << ", OriginalAddend=" << OriginalAddend;

  }

  LLVM_DUMP_METHOD void dump() const { print(errs()); }

};

class MCELFObjectTargetWriter : public MCObjectTargetWriter {

  const uint8_t OSABI;

  const uint8_t ABIVersion;

  const uint16_t EMachine;

  const unsigned HasRelocationAddend : 1;

  const unsigned Is64Bit : 1;

protected:

  MCELFObjectTargetWriter(bool Is64Bit_, uint8_t OSABI_, uint16_t EMachine_,

                          bool HasRelocationAddend_, uint8_t ABIVersion_ = 0);

public:

  virtual ~MCELFObjectTargetWriter() = default;

  Triple::ObjectFormatType getFormat() const override { return Triple::ELF; }

  static bool classof(const MCObjectTargetWriter *W) {

    return W->getFormat() == Triple::ELF;

  }

  static uint8_t getOSABI(Triple::OSType OSType) {

    switch (OSType) {

      case Triple::CloudABI:

        return ELF::ELFOSABI_CLOUDABI;

      case Triple::HermitCore:

        return ELF::ELFOSABI_STANDALONE;

      case Triple::PS4:

      case Triple::FreeBSD:

        return ELF::ELFOSABI_FREEBSD;

      case Triple::Solaris:

        return ELF::ELFOSABI_SOLARIS;

      default:

        return ELF::ELFOSABI_NONE;

    }

  }

  virtual unsigned getRelocType(MCContext &Ctx, const MCValue &Target,

                                const MCFixup &Fixup, bool IsPCRel) const = 0;

  virtual bool needsRelocateWithSymbol(const MCSymbol &Sym,

                                       unsigned Type) const;

  virtual void sortRelocs(const MCAssembler &Asm,

                          std::vector<ELFRelocationEntry> &Relocs);

  virtual void addTargetSectionFlags(MCContext &Ctx, MCSectionELF &Sec);

  /// \name Accessors

  /// @{

  uint8_t getOSABI() const { return OSABI; }

  uint8_t getABIVersion() const { return ABIVersion; }

  uint16_t getEMachine() const { return EMachine; }

  bool hasRelocationAddend() const { return HasRelocationAddend; }

  bool is64Bit() const { return Is64Bit; }

  /// @}

  // Instead of changing everyone's API we pack the N64 Type fields

  // into the existing 32 bit data unsigned.

#define R_TYPE_SHIFT 0

#define R_TYPE_MASK 0xffffff00

#define R_TYPE2_SHIFT 8

#define R_TYPE2_MASK 0xffff00ff

#define R_TYPE3_SHIFT 16

#define R_TYPE3_MASK 0xff00ffff

#define R_SSYM_SHIFT 24

#define R_SSYM_MASK 0x00ffffff

  // N64 relocation type accessors

  uint8_t getRType(uint32_t Type) const {

    return (unsigned)((Type >> R_TYPE_SHIFT) & 0xff);

  }

  uint8_t getRType2(uint32_t Type) const {

    return (unsigned)((Type >> R_TYPE2_SHIFT) & 0xff);

  }

  uint8_t getRType3(uint32_t Type) const {

    return (unsigned)((Type >> R_TYPE3_SHIFT) & 0xff);

  }

  uint8_t getRSsym(uint32_t Type) const {

    return (unsigned)((Type >> R_SSYM_SHIFT) & 0xff);

  }

  // N64 relocation type setting

  static unsigned setRTypes(unsigned Value1, unsigned Value2, unsigned Value3) {

    return ((Value1 & 0xff) << R_TYPE_SHIFT) |

           ((Value2 & 0xff) << R_TYPE2_SHIFT) |

           ((Value3 & 0xff) << R_TYPE3_SHIFT);

  }

  unsigned setRSsym(unsigned Value, unsigned Type) const {

    return (Type & R_SSYM_MASK) | ((Value & 0xff) << R_SSYM_SHIFT);

  }

  // On AArch64, return a new section to be added to the ELF object that

  // contains relocations used to describe every symbol that should have memory

  // tags applied. Returns nullptr if no such section is necessary (i.e. there's

  // no tagged globals).

  virtual MCSectionELF *getMemtagRelocsSection(MCContext &Ctx) const {

    return nullptr;

  }

};

/// Construct a new ELF writer instance.

///

/// \param MOTW - The target specific ELF writer subclass.

/// \param OS - The stream to write to.

/// \returns The constructed object writer.

std::unique_ptr<MCObjectWriter>

createELFObjectWriter(std::unique_ptr<MCELFObjectTargetWriter> MOTW,

                      raw_pwrite_stream &OS, bool IsLittleEndian);

std::unique_ptr<MCObjectWriter>

createELFDwoObjectWriter(std::unique_ptr<MCELFObjectTargetWriter> MOTW,

                         raw_pwrite_stream &OS, raw_pwrite_stream &DwoOS,

                         bool IsLittleEndian);

} // end namespace llvm

#endif // LLVM_MC_MCELFOBJECTWRITER_H