llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.h

//===-- RISCVELFStreamer.h - RISC-V ELF Target Streamer ---------*- 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_LIB_TARGET_RISCV_MCTARGETDESC_RISCVELFSTREAMER_H
#define LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVELFSTREAMER_H

#include "RISCVTargetStreamer.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/MC/MCELFStreamer.h"

namespace llvm {

class RISCVELFStreamer : public MCELFStreamer {
  void reset() override;
  void emitDataMappingSymbol();
  void emitInstructionsMappingSymbol();
  void emitMappingSymbol(StringRef Name);

  enum ElfMappingSymbol { EMS_None, EMS_Instructions, EMS_Data };

  DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
  ElfMappingSymbol LastEMS = EMS_None;

  // Active ISA string propagated from RISCVTargetELFStreamer. When non-empty,
  // it is used as the suffix for "$x<ISA>" mapping symbols.
  std::string MappingSymbolArch;

  // ISA suffix last emitted via "$x<ISA>" in the current section, and the
  // per-section history preserved across changeSection. A new mapping symbol
  // is emitted whenever LastEMS != EMS_Instructions or
  // LastEmittedArch != MappingSymbolArch, so the ISA in effect at each
  // instruction run is always recorded.
  std::string LastEmittedArch;
  DenseMap<const MCSection *, std::string> LastEmittedArchInSection;

public:
  RISCVELFStreamer(MCContext &C, std::unique_ptr<MCAsmBackend> MAB,
                   std::unique_ptr<MCObjectWriter> MOW,
                   std::unique_ptr<MCCodeEmitter> MCE);

  void changeSection(MCSection *Section, uint32_t Subsection) override;
  void emitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI) override;
  void emitBytes(StringRef Data) override;
  void emitFill(const MCExpr &NumBytes, uint64_t FillValue, SMLoc Loc) override;
  void emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override;

  void setMappingSymbolArch(StringRef Arch);
};

class RISCVTargetELFStreamer : public RISCVTargetStreamer {
private:
  StringRef CurrentVendor;

  // Initial ISA string derived from the subtarget features in the constructor.
  // Used to re-establish state on reset().
  std::string InitialArchString;

  // Current ISA string, kept in sync with each .option arch/rvc/norvc/pop
  // and .attribute arch directive. Used to avoid propagating redundant ISA
  // updates to the streamer when the ISA does not actually change (e.g.,
  // .option rvc when C is already enabled).
  std::string ArchString;
  SmallVector<std::string, 4> ArchStringStack;

  MCSection *AttributeSection = nullptr;

  void emitAttribute(unsigned Attribute, unsigned Value) override;
  void emitTextAttribute(unsigned Attribute, StringRef String) override;
  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
                            StringRef StringValue) override;
  void finishAttributeSection() override;

  void reset() override;

public:
  RISCVELFStreamer &getStreamer();
  RISCVTargetELFStreamer(MCStreamer &S, const MCSubtargetInfo &STI);

  // Update ArchString and propagate the change to the streamer so the next
  // instruction-run emits an ISA-specific mapping symbol. A no-op when
  // Arch == ArchString (deduplication).
  void setArchString(StringRef Arch) override;
  void emitDirectiveOptionExact() override;
  void emitDirectiveOptionNoExact() override;
  void emitDirectiveOptionPIC() override;
  void emitDirectiveOptionNoPIC() override;
  void emitDirectiveOptionPop() override;
  void emitDirectiveOptionPush() override;
  void emitDirectiveOptionRelax() override;
  void emitDirectiveOptionNoRelax() override;
  void emitDirectiveOptionRVC() override;
  void emitDirectiveOptionNoRVC() override;
  void emitDirectiveVariantCC(MCSymbol &Symbol) override;

  void emitNoteGnuPropertySection(const uint32_t Feature1And);
  void finish() override;
};

MCStreamer *createRISCVELFStreamer(const Triple &, MCContext &C,
                                   std::unique_ptr<MCAsmBackend> &&MAB,
                                   std::unique_ptr<MCObjectWriter> &&MOW,
                                   std::unique_ptr<MCCodeEmitter> &&MCE);
} // namespace llvm

#endif // LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVELFSTREAMER_H