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//===-- llvm/Target/TargetLoweringObjectFile.h - Object Info ----*- 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

//

//===----------------------------------------------------------------------===//

//

// This file implements classes used to handle lowerings specific to common

// object file formats.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H

#define LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H

#include "llvm/MC/MCObjectFileInfo.h"

#include "llvm/MC/MCRegister.h"

#include <cstdint>

namespace llvm {

struct Align;

class Constant;

class DataLayout;

class Function;

class GlobalObject;

class GlobalValue;

class MachineBasicBlock;

class MachineModuleInfo;

class Mangler;

class MCContext;

class MCExpr;

class MCSection;

class MCSymbol;

class MCSymbolRefExpr;

class MCStreamer;

class MCValue;

class Module;

class SectionKind;

class StringRef;

class TargetMachine;

class DSOLocalEquivalent;

class TargetLoweringObjectFile : public MCObjectFileInfo {

  /// Name-mangler for global names.

  Mangler *Mang = nullptr;

protected:

  bool SupportIndirectSymViaGOTPCRel = false;

  bool SupportGOTPCRelWithOffset = true;

  bool SupportDebugThreadLocalLocation = true;

  bool SupportDSOLocalEquivalentLowering = false;

  /// PersonalityEncoding, LSDAEncoding, TTypeEncoding - Some encoding values

  /// for EH.

  unsigned PersonalityEncoding = 0;

  unsigned LSDAEncoding = 0;

  unsigned TTypeEncoding = 0;

  unsigned CallSiteEncoding = 0;

  /// This section contains the static constructor pointer list.

  MCSection *StaticCtorSection = nullptr;

  /// This section contains the static destructor pointer list.

  MCSection *StaticDtorSection = nullptr;

  const TargetMachine *TM = nullptr;

public:

  TargetLoweringObjectFile() = default;

  TargetLoweringObjectFile(const TargetLoweringObjectFile &) = delete;

  TargetLoweringObjectFile &

  operator=(const TargetLoweringObjectFile &) = delete;

  virtual ~TargetLoweringObjectFile();

  Mangler &getMangler() const { return *Mang; }

  /// This method must be called before any actual lowering is done.  This

  /// specifies the current context for codegen, and gives the lowering

  /// implementations a chance to set up their default sections.

  virtual void Initialize(MCContext &ctx, const TargetMachine &TM);

  virtual void emitPersonalityValue(MCStreamer &Streamer, const DataLayout &TM,

                                    const MCSymbol *Sym) const;

  /// Emit the module-level metadata that the platform cares about.

  virtual void emitModuleMetadata(MCStreamer &Streamer, Module &M) const {}

  /// Emit Call Graph Profile metadata.

  void emitCGProfileMetadata(MCStreamer &Streamer, Module &M) const;

  /// Get the module-level metadata that the platform cares about.

  virtual void getModuleMetadata(Module &M) {}

  /// Given a constant with the SectionKind, return a section that it should be

  /// placed in.

  virtual MCSection *getSectionForConstant(const DataLayout &DL,

                                           SectionKind Kind, const Constant *C,

                                           Align &Alignment) const;

  virtual MCSection *

  getSectionForMachineBasicBlock(const Function &F,

                                 const MachineBasicBlock &MBB,

                                 const TargetMachine &TM) const;

  virtual MCSection *

  getUniqueSectionForFunction(const Function &F,

                              const TargetMachine &TM) const;

  /// Classify the specified global variable into a set of target independent

  /// categories embodied in SectionKind.

  static SectionKind getKindForGlobal(const GlobalObject *GO,

                                      const TargetMachine &TM);

  /// This method computes the appropriate section to emit the specified global

  /// variable or function definition. This should not be passed external (or

  /// available externally) globals.

  MCSection *SectionForGlobal(const GlobalObject *GO, SectionKind Kind,

                              const TargetMachine &TM) const;

  /// This method computes the appropriate section to emit the specified global

  /// variable or function definition. This should not be passed external (or

  /// available externally) globals.

  MCSection *SectionForGlobal(const GlobalObject *GO,

                              const TargetMachine &TM) const;

  virtual void getNameWithPrefix(SmallVectorImpl<char> &OutName,

                                 const GlobalValue *GV,

                                 const TargetMachine &TM) const;

  virtual MCSection *getSectionForJumpTable(const Function &F,

                                            const TargetMachine &TM) const;

  virtual MCSection *getSectionForLSDA(const Function &, const MCSymbol &,

                                       const TargetMachine &) const {

    return LSDASection;

  }

  virtual bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,

                                                   const Function &F) const;

  /// Targets should implement this method to assign a section to globals with

  /// an explicit section specfied. The implementation of this method can

  /// assume that GO->hasSection() is true.

  virtual MCSection *

  getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,

                           const TargetMachine &TM) const = 0;

  /// Return an MCExpr to use for a reference to the specified global variable

  /// from exception handling information.

  virtual const MCExpr *getTTypeGlobalReference(const GlobalValue *GV,

                                                unsigned Encoding,

                                                const TargetMachine &TM,

                                                MachineModuleInfo *MMI,

                                                MCStreamer &Streamer) const;

  /// Return the MCSymbol for a private symbol with global value name as its

  /// base, with the specified suffix.

  MCSymbol *getSymbolWithGlobalValueBase(const GlobalValue *GV,

                                         StringRef Suffix,

                                         const TargetMachine &TM) const;

  // The symbol that gets passed to .cfi_personality.

  virtual MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV,

                                            const TargetMachine &TM,

                                            MachineModuleInfo *MMI) const;

  unsigned getPersonalityEncoding() const { return PersonalityEncoding; }

  unsigned getLSDAEncoding() const { return LSDAEncoding; }

  unsigned getTTypeEncoding() const { return TTypeEncoding; }

  unsigned getCallSiteEncoding() const;

  const MCExpr *getTTypeReference(const MCSymbolRefExpr *Sym, unsigned Encoding,

                                  MCStreamer &Streamer) const;

  virtual MCSection *getStaticCtorSection(unsigned Priority,

                                          const MCSymbol *KeySym) const {

    return StaticCtorSection;

  }

  virtual MCSection *getStaticDtorSection(unsigned Priority,

                                          const MCSymbol *KeySym) const {

    return StaticDtorSection;

  }

  /// Create a symbol reference to describe the given TLS variable when

  /// emitting the address in debug info.

  virtual const MCExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const;

  virtual const MCExpr *lowerRelativeReference(const GlobalValue *LHS,

                                               const GlobalValue *RHS,

                                               const TargetMachine &TM) const {

    return nullptr;

  }

  /// Target supports a native lowering of a dso_local_equivalent constant

  /// without needing to replace it with equivalent IR.

  bool supportDSOLocalEquivalentLowering() const {

    return SupportDSOLocalEquivalentLowering;

  }

  virtual const MCExpr *lowerDSOLocalEquivalent(const DSOLocalEquivalent *Equiv,

                                                const TargetMachine &TM) const {

    return nullptr;

  }

  /// Target supports replacing a data "PC"-relative access to a symbol

  /// through another symbol, by accessing the later via a GOT entry instead?

  bool supportIndirectSymViaGOTPCRel() const {

    return SupportIndirectSymViaGOTPCRel;

  }

  /// Target GOT "PC"-relative relocation supports encoding an additional

  /// binary expression with an offset?

  bool supportGOTPCRelWithOffset() const {

    return SupportGOTPCRelWithOffset;

  }

  /// Target supports TLS offset relocation in debug section?

  bool supportDebugThreadLocalLocation() const {

    return SupportDebugThreadLocalLocation;

  }

  /// Returns the register used as static base in RWPI variants.

  virtual MCRegister getStaticBase() const { return MCRegister::NoRegister; }

  /// Get the target specific RWPI relocation.

  virtual const MCExpr *getIndirectSymViaRWPI(const MCSymbol *Sym) const {

    return nullptr;

  }

  /// Get the target specific PC relative GOT entry relocation

  virtual const MCExpr *getIndirectSymViaGOTPCRel(const GlobalValue *GV,

                                                  const MCSymbol *Sym,

                                                  const MCValue &MV,

                                                  int64_t Offset,

                                                  MachineModuleInfo *MMI,

                                                  MCStreamer &Streamer) const {

    return nullptr;

  }

  /// If supported, return the section to use for the llvm.commandline

  /// metadata. Otherwise, return nullptr.

  virtual MCSection *getSectionForCommandLines() const {

    return nullptr;

  }

  /// On targets that use separate function descriptor symbols, return a section

  /// for the descriptor given its symbol. Use only with defined functions.

  virtual MCSection *

  getSectionForFunctionDescriptor(const Function *F,

                                  const TargetMachine &TM) const {

    return nullptr;

  }

  /// On targets that support TOC entries, return a section for the entry given

  /// the symbol it refers to.

  /// TODO: Implement this interface for existing ELF targets.

  virtual MCSection *getSectionForTOCEntry(const MCSymbol *S,

                                           const TargetMachine &TM) const {

    return nullptr;

  }

  /// On targets that associate external references with a section, return such

  /// a section for the given external global.

  virtual MCSection *

  getSectionForExternalReference(const GlobalObject *GO,

                                 const TargetMachine &TM) const {

    return nullptr;

  }

  /// Targets that have a special convention for their symbols could use

  /// this hook to return a specialized symbol.

  virtual MCSymbol *getTargetSymbol(const GlobalValue *GV,

                                    const TargetMachine &TM) const {

    return nullptr;

  }

  /// If supported, return the function entry point symbol.

  /// Otherwise, returns nullptr.

  /// Func must be a function or an alias which has a function as base object.

  virtual MCSymbol *getFunctionEntryPointSymbol(const GlobalValue *Func,

                                                const TargetMachine &TM) const {

    return nullptr;

  }

protected:

  virtual MCSection *SelectSectionForGlobal(const GlobalObject *GO,

                                            SectionKind Kind,

                                            const TargetMachine &TM) const = 0;

};

} // end namespace llvm

#endif // LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H