RISCV/MCTargetDesc/RISCVInstPrinter.cpp

//===-- RISCVInstPrinter.cpp - Convert RISCV MCInst to asm syntax ---------===//
//
// 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 class prints an RISCV MCInst to a .s file.
//
//===----------------------------------------------------------------------===//

#include "RISCVInstPrinter.h"
#include "MCTargetDesc/RISCVMCExpr.h"
#include "Utils/RISCVBaseInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
using namespace llvm;

#define DEBUG_TYPE "asm-printer"

// Include the auto-generated portion of the assembly writer.
#define PRINT_ALIAS_INSTR
#include "RISCVGenAsmWriter.inc"

// Include the auto-generated portion of the compress emitter.
#define GEN_UNCOMPRESS_INSTR
#include "RISCVGenCompressInstEmitter.inc"

static cl::opt<bool>
    NoAliases("riscv-no-aliases",
              cl::desc("Disable the emission of assembler pseudo instructions"),
              cl::init(false), cl::Hidden);

static cl::opt<bool>
    ArchRegNames("riscv-arch-reg-names",
                 cl::desc("Print architectural register names rather than the "
                          "ABI names (such as x2 instead of sp)"),
                 cl::init(false), cl::Hidden);

// The command-line flags above are used by llvm-mc and llc. They can be used by
// `llvm-objdump`, but we override their values here to handle options passed to
// `llvm-objdump` with `-M` (which matches GNU objdump). There did not seem to
// be an easier way to allow these options in all these tools, without doing it
// this way.
bool RISCVInstPrinter::applyTargetSpecificCLOption(StringRef Opt) {
  if (Opt == "no-aliases") {
    NoAliases = true;
    return true;
  }
  if (Opt == "numeric") {
    ArchRegNames = true;
    return true;
  }

  return false;
}

void RISCVInstPrinter::printInst(const MCInst *MI, uint64_t Address,
                                 StringRef Annot, const MCSubtargetInfo &STI,
                                 raw_ostream &O) {
  bool Res = false;
  const MCInst *NewMI = MI;
  MCInst UncompressedMI;
  if (!NoAliases)
    Res = uncompressInst(UncompressedMI, *MI, MRI, STI);
  if (Res)
    NewMI = const_cast<MCInst *>(&UncompressedMI);
  if (NoAliases || !printAliasInstr(NewMI, Address, STI, O))
    printInstruction(NewMI, Address, STI, O);
  printAnnotation(O, Annot);
}

void RISCVInstPrinter::printRegName(raw_ostream &O, unsigned RegNo) const {
  O << getRegisterName(RegNo);
}

void RISCVInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
                                    const MCSubtargetInfo &STI, raw_ostream &O,
                                    const char *Modifier) {
  assert((Modifier == 0 || Modifier[0] == 0) && "No modifiers supported");
  const MCOperand &MO = MI->getOperand(OpNo);

  if (MO.isReg()) {
    printRegName(O, MO.getReg());
    return;
  }

  if (MO.isImm()) {
    O << MO.getImm();
    return;
  }

  assert(MO.isExpr() && "Unknown operand kind in printOperand");
  MO.getExpr()->print(O, &MAI);
}

void RISCVInstPrinter::printCSRSystemRegister(const MCInst *MI, unsigned OpNo,
                                              const MCSubtargetInfo &STI,
                                              raw_ostream &O) {
  unsigned Imm = MI->getOperand(OpNo).getImm();
  auto SysReg = RISCVSysReg::lookupSysRegByEncoding(Imm);
  if (SysReg && SysReg->haveRequiredFeatures(STI.getFeatureBits()))
    O << SysReg->Name;
  else
    O << Imm;
}

void RISCVInstPrinter::printFenceArg(const MCInst *MI, unsigned OpNo,
                                     const MCSubtargetInfo &STI,
                                     raw_ostream &O) {
  unsigned FenceArg = MI->getOperand(OpNo).getImm();
  assert (((FenceArg >> 4) == 0) && "Invalid immediate in printFenceArg");

  if ((FenceArg & RISCVFenceField::I) != 0)
    O << 'i';
  if ((FenceArg & RISCVFenceField::O) != 0)
    O << 'o';
  if ((FenceArg & RISCVFenceField::R) != 0)
    O << 'r';
  if ((FenceArg & RISCVFenceField::W) != 0)
    O << 'w';
  if (FenceArg == 0)
    O << "unknown";
}

void RISCVInstPrinter::printFRMArg(const MCInst *MI, unsigned OpNo,
                                   const MCSubtargetInfo &STI, raw_ostream &O) {
  auto FRMArg =
      static_cast<RISCVFPRndMode::RoundingMode>(MI->getOperand(OpNo).getImm());
  O << RISCVFPRndMode::roundingModeToString(FRMArg);
}

void RISCVInstPrinter::printAtomicMemOp(const MCInst *MI, unsigned OpNo,
                                        const MCSubtargetInfo &STI,
                                        raw_ostream &O) {
  const MCOperand &MO = MI->getOperand(OpNo);

  assert(MO.isReg() && "printAtomicMemOp can only print register operands");
  O << "(";
  printRegName(O, MO.getReg());
  O << ")";
  return;
}

void RISCVInstPrinter::printVTypeI(const MCInst *MI, unsigned OpNo,
                                   const MCSubtargetInfo &STI, raw_ostream &O) {
  unsigned Imm = MI->getOperand(OpNo).getImm();
  unsigned Sew = (Imm >> 2) & 0x7;
  unsigned Lmul = Imm & 0x3;

  Lmul = 0x1 << Lmul;
  Sew = 0x1 << (Sew + 3);
  O << "e" << Sew << ",m" << Lmul;
}

void RISCVInstPrinter::printVMaskReg(const MCInst *MI, unsigned OpNo,
                                     const MCSubtargetInfo &STI,
                                     raw_ostream &O) {
  const MCOperand &MO = MI->getOperand(OpNo);

  assert(MO.isReg() && "printVMaskReg can only print register operands");
  if (MO.getReg() == RISCV::NoRegister)
    return;
  O << ", ";
  printRegName(O, MO.getReg());
  O << ".t";
}

void RISCVInstPrinter::printSImm5Plus1(const MCInst *MI, unsigned OpNo,
                                       const MCSubtargetInfo &STI,
                                       raw_ostream &O) {
  const MCOperand &MO = MI->getOperand(OpNo);

  assert(MO.isImm() && "printSImm5Plus1 can only print constant operands");
  O << MO.getImm() + 1;
}

const char *RISCVInstPrinter::getRegisterName(unsigned RegNo) {
  return getRegisterName(RegNo, ArchRegNames ? RISCV::NoRegAltName
                                             : RISCV::ABIRegAltName);
}