//===-- VEAsmParser.cpp - Parse VE assembly to MCInst instructions --------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "MCTargetDesc/VEMCExpr.h"
#include "MCTargetDesc/VEMCTargetDesc.h"
#include "TargetInfo/VETargetInfo.h"
#include "VE.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <memory>

using namespace llvm;

#define DEBUG_TYPE "ve-asmparser"

namespace {

class VEOperand;

class VEAsmParser : public MCTargetAsmParser {
  MCAsmParser &Parser;

  /// @name Auto-generated Match Functions
  /// {

#define GET_ASSEMBLER_HEADER
#include "VEGenAsmMatcher.inc"

  /// }

  // public interface of the MCTargetAsmParser.
  bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                               OperandVector &Operands, MCStreamer &Out,
                               uint64_t &ErrorInfo,
                               bool MatchingInlineAsm) override;
  bool ParseRegister(unsigned &RegNo, SMLoc &StartLoc, SMLoc &EndLoc) override;
  int parseRegisterName(unsigned (*matchFn)(StringRef));
  OperandMatchResultTy tryParseRegister(unsigned &RegNo, SMLoc &StartLoc,
                                        SMLoc &EndLoc) override;
  bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                        SMLoc NameLoc, OperandVector &Operands) override;
  bool ParseDirective(AsmToken DirectiveID) override;

  // Custom parse functions for VE specific operands.
  OperandMatchResultTy parseMEMOperand(OperandVector &Operands);
  OperandMatchResultTy parseOperand(OperandVector &Operands, StringRef Name);
  OperandMatchResultTy parseVEAsmOperand(std::unique_ptr<VEOperand> &Operand);

public:
  VEAsmParser(const MCSubtargetInfo &sti, MCAsmParser &parser,
              const MCInstrInfo &MII, const MCTargetOptions &Options)
      : MCTargetAsmParser(Options, sti, MII), Parser(parser) {
    // Initialize the set of available features.
    setAvailableFeatures(ComputeAvailableFeatures(getSTI().getFeatureBits()));
  }
};

} // end anonymous namespace

namespace {

/// VEOperand - Instances of this class represent a parsed VE machine
/// instruction.
class VEOperand : public MCParsedAsmOperand {
private:
  enum KindTy {
    k_Token,
    k_Register,
    k_Immediate,
    // SX-Aurora ASX form is disp(index, base).
    k_MemoryRegRegImm,  // base=reg, index=reg, disp=imm
    k_MemoryRegImmImm,  // base=reg, index=imm, disp=imm
    k_MemoryZeroRegImm, // base=0, index=reg, disp=imm
    k_MemoryZeroImmImm, // base=0, index=imm, disp=imm
  } Kind;

  SMLoc StartLoc, EndLoc;

  struct Token {
    const char *Data;
    unsigned Length;
  };

  struct RegOp {
    unsigned RegNum;
  };

  struct ImmOp {
    const MCExpr *Val;
  };

  struct MemOp {
    unsigned Base;
    unsigned IndexReg;
    const MCExpr *Index;
    const MCExpr *Offset;
  };

  union {
    struct Token Tok;
    struct RegOp Reg;
    struct ImmOp Imm;
    struct MemOp Mem;
  };

public:
  VEOperand(KindTy K) : MCParsedAsmOperand(), Kind(K) {}

  bool isToken() const override { return Kind == k_Token; }
  bool isReg() const override { return Kind == k_Register; }
  bool isImm() const override { return Kind == k_Immediate; }
  bool isMem() const override {
    return isMEMrri() || isMEMrii() || isMEMzri() || isMEMzii() || isMEMri() ||
           isMEMzi();
  }
  bool isMEMrri() const { return Kind == k_MemoryRegRegImm; }
  bool isMEMrii() const { return Kind == k_MemoryRegImmImm; }
  bool isMEMzri() const { return Kind == k_MemoryZeroRegImm; }
  bool isMEMzii() const { return Kind == k_MemoryZeroImmImm; }
  // isMEMri and isMEMzi will be implemented later.
  bool isMEMri() const { return false; }
  bool isMEMzi() const { return false; }
  bool isSImm7() {
    if (!isImm())
      return false;

    // Constant case
    if (const MCConstantExpr *ConstExpr = dyn_cast<MCConstantExpr>(Imm.Val)) {
      int64_t Value = ConstExpr->getValue();
      return isInt<7>(Value);
    }
    return false;
  }

  StringRef getToken() const {
    assert(Kind == k_Token && "Invalid access!");
    return StringRef(Tok.Data, Tok.Length);
  }

  unsigned getReg() const override {
    assert((Kind == k_Register) && "Invalid access!");
    return Reg.RegNum;
  }

  const MCExpr *getImm() const {
    assert((Kind == k_Immediate) && "Invalid access!");
    return Imm.Val;
  }

  unsigned getMemBase() const {
    assert((Kind == k_MemoryRegRegImm || Kind == k_MemoryRegImmImm) &&
           "Invalid access!");
    return Mem.Base;
  }

  unsigned getMemIndexReg() const {
    assert((Kind == k_MemoryRegRegImm || Kind == k_MemoryZeroRegImm) &&
           "Invalid access!");
    return Mem.IndexReg;
  }

  const MCExpr *getMemIndex() const {
    assert((Kind == k_MemoryRegImmImm || Kind == k_MemoryZeroImmImm) &&
           "Invalid access!");
    return Mem.Index;
  }

  const MCExpr *getMemOffset() const {
    assert((Kind == k_MemoryRegRegImm || Kind == k_MemoryRegImmImm ||
            Kind == k_MemoryZeroImmImm || Kind == k_MemoryZeroRegImm) &&
           "Invalid access!");
    return Mem.Offset;
  }

  void setMemOffset(const MCExpr *off) {
    assert((Kind == k_MemoryRegRegImm || Kind == k_MemoryRegImmImm ||
            Kind == k_MemoryZeroImmImm || Kind == k_MemoryZeroRegImm) &&
           "Invalid access!");
    Mem.Offset = off;
  }

  /// getStartLoc - Get the location of the first token of this operand.
  SMLoc getStartLoc() const override { return StartLoc; }
  /// getEndLoc - Get the location of the last token of this operand.
  SMLoc getEndLoc() const override { return EndLoc; }

  void print(raw_ostream &OS) const override {
    switch (Kind) {
    case k_Token:
      OS << "Token: " << getToken() << "\n";
      break;
    case k_Register:
      OS << "Reg: #" << getReg() << "\n";
      break;
    case k_Immediate:
      OS << "Imm: " << getImm() << "\n";
      break;
    case k_MemoryRegRegImm:
      assert(getMemOffset() != nullptr);
      OS << "Mem: #" << getMemBase() << "+#" << getMemIndexReg() << "+"
         << *getMemOffset() << "\n";
      break;
    case k_MemoryRegImmImm:
      assert(getMemIndex() != nullptr && getMemOffset() != nullptr);
      OS << "Mem: #" << getMemBase() << "+" << *getMemIndex() << "+"
         << *getMemOffset() << "\n";
      break;
    case k_MemoryZeroRegImm:
      assert(getMemOffset() != nullptr);
      OS << "Mem: 0+#" << getMemIndexReg() << "+" << *getMemOffset() << "\n";
      break;
    case k_MemoryZeroImmImm:
      assert(getMemIndex() != nullptr && getMemOffset() != nullptr);
      OS << "Mem: 0+" << *getMemIndex() << "+" << *getMemOffset() << "\n";
      break;
    }
  }

  void addRegOperands(MCInst &Inst, unsigned N) const {
    assert(N == 1 && "Invalid number of operands!");
    Inst.addOperand(MCOperand::createReg(getReg()));
  }

  void addImmOperands(MCInst &Inst, unsigned N) const {
    assert(N == 1 && "Invalid number of operands!");
    const MCExpr *Expr = getImm();
    addExpr(Inst, Expr);
  }

  void addSImm7Operands(MCInst &Inst, unsigned N) const {
    addImmOperands(Inst, N);
  }

  void addExpr(MCInst &Inst, const MCExpr *Expr) const {
    // Add as immediate when possible.  Null MCExpr = 0.
    if (!Expr)
      Inst.addOperand(MCOperand::createImm(0));
    else if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(Expr))
      Inst.addOperand(MCOperand::createImm(CE->getValue()));
    else
      Inst.addOperand(MCOperand::createExpr(Expr));
  }

  void addMEMrriOperands(MCInst &Inst, unsigned N) const {
    assert(N == 3 && "Invalid number of operands!");

    Inst.addOperand(MCOperand::createReg(getMemBase()));
    Inst.addOperand(MCOperand::createReg(getMemIndexReg()));
    addExpr(Inst, getMemOffset());
  }

  void addMEMriiOperands(MCInst &Inst, unsigned N) const {
    assert(N == 3 && "Invalid number of operands!");

    Inst.addOperand(MCOperand::createReg(getMemBase()));
    addExpr(Inst, getMemIndex());
    addExpr(Inst, getMemOffset());
  }

  void addMEMzriOperands(MCInst &Inst, unsigned N) const {
    assert(N == 3 && "Invalid number of operands!");

    Inst.addOperand(MCOperand::createImm(0));
    Inst.addOperand(MCOperand::createReg(getMemIndexReg()));
    addExpr(Inst, getMemOffset());
  }

  void addMEMziiOperands(MCInst &Inst, unsigned N) const {
    assert(N == 3 && "Invalid number of operands!");

    Inst.addOperand(MCOperand::createImm(0));
    addExpr(Inst, getMemIndex());
    addExpr(Inst, getMemOffset());
  }

  void addMEMriOperands(MCInst &Inst, unsigned N) const {
    // FIXME: implement
  }

  void addMEMziOperands(MCInst &Inst, unsigned N) const {
    // FIXME: implement
  }

  static std::unique_ptr<VEOperand> CreateToken(StringRef Str, SMLoc S) {
    auto Op = std::make_unique<VEOperand>(k_Token);
    Op->Tok.Data = Str.data();
    Op->Tok.Length = Str.size();
    Op->StartLoc = S;
    Op->EndLoc = S;
    return Op;
  }

  static std::unique_ptr<VEOperand> CreateReg(unsigned RegNum, SMLoc S,
                                              SMLoc E) {
    auto Op = std::make_unique<VEOperand>(k_Register);
    Op->Reg.RegNum = RegNum;
    Op->StartLoc = S;
    Op->EndLoc = E;
    return Op;
  }

  static std::unique_ptr<VEOperand> CreateImm(const MCExpr *Val, SMLoc S,
                                              SMLoc E) {
    auto Op = std::make_unique<VEOperand>(k_Immediate);
    Op->Imm.Val = Val;
    Op->StartLoc = S;
    Op->EndLoc = E;
    return Op;
  }

  static std::unique_ptr<VEOperand>
  MorphToMEMrri(unsigned Base, unsigned Index, std::unique_ptr<VEOperand> Op) {
    const MCExpr *Imm = Op->getImm();
    Op->Kind = k_MemoryRegRegImm;
    Op->Mem.Base = Base;
    Op->Mem.IndexReg = Index;
    Op->Mem.Index = nullptr;
    Op->Mem.Offset = Imm;
    return Op;
  }

  static std::unique_ptr<VEOperand>
  MorphToMEMrii(unsigned Base, const MCExpr *Index,
                std::unique_ptr<VEOperand> Op) {
    const MCExpr *Imm = Op->getImm();
    Op->Kind = k_MemoryRegImmImm;
    Op->Mem.Base = Base;
    Op->Mem.IndexReg = 0;
    Op->Mem.Index = Index;
    Op->Mem.Offset = Imm;
    return Op;
  }

  static std::unique_ptr<VEOperand>
  MorphToMEMzri(unsigned Index, std::unique_ptr<VEOperand> Op) {
    const MCExpr *Imm = Op->getImm();
    Op->Kind = k_MemoryZeroRegImm;
    Op->Mem.Base = 0;
    Op->Mem.IndexReg = Index;
    Op->Mem.Index = nullptr;
    Op->Mem.Offset = Imm;
    return Op;
  }

  static std::unique_ptr<VEOperand>
  MorphToMEMzii(const MCExpr *Index, std::unique_ptr<VEOperand> Op) {
    const MCExpr *Imm = Op->getImm();
    Op->Kind = k_MemoryZeroImmImm;
    Op->Mem.Base = 0;
    Op->Mem.IndexReg = 0;
    Op->Mem.Index = Index;
    Op->Mem.Offset = Imm;
    return Op;
  }
};

} // end anonymous namespace

bool VEAsmParser::MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                          OperandVector &Operands,
                                          MCStreamer &Out, uint64_t &ErrorInfo,
                                          bool MatchingInlineAsm) {
  MCInst Inst;
  unsigned MatchResult =
      MatchInstructionImpl(Operands, Inst, ErrorInfo, MatchingInlineAsm);
  switch (MatchResult) {
  case Match_Success:
    Inst.setLoc(IDLoc);
    Out.emitInstruction(Inst, getSTI());
    return false;

  case Match_MissingFeature:
    return Error(IDLoc,
                 "instruction requires a CPU feature not currently enabled");

  case Match_InvalidOperand: {
    SMLoc ErrorLoc = IDLoc;
    if (ErrorInfo != ~0ULL) {
      if (ErrorInfo >= Operands.size())
        return Error(IDLoc, "too few operands for instruction");

      ErrorLoc = ((VEOperand &)*Operands[ErrorInfo]).getStartLoc();
      if (ErrorLoc == SMLoc())
        ErrorLoc = IDLoc;
    }

    return Error(ErrorLoc, "invalid operand for instruction");
  }
  case Match_MnemonicFail:
    return Error(IDLoc, "invalid instruction mnemonic");
  }
  llvm_unreachable("Implement any new match types added!");
}

bool VEAsmParser::ParseRegister(unsigned &RegNo, SMLoc &StartLoc,
                                SMLoc &EndLoc) {
  if (tryParseRegister(RegNo, StartLoc, EndLoc) != MatchOperand_Success)
    return Error(StartLoc, "invalid register name");
  return false;
}

/// Parses a register name using a given matching function.
/// Checks for lowercase or uppercase if necessary.
int VEAsmParser::parseRegisterName(unsigned (*matchFn)(StringRef)) {
  StringRef Name = Parser.getTok().getString();

  int RegNum = matchFn(Name);

  // GCC supports case insensitive register names. All of the VE registers
  // are all lower case.
  if (RegNum == VE::NoRegister) {
    RegNum = matchFn(Name.lower());
  }

  return RegNum;
}

/// Maps from the set of all register names to a register number.
/// \note Generated by TableGen.
static unsigned MatchRegisterName(StringRef Name);

/// Maps from the set of all alternative registernames to a register number.
/// \note Generated by TableGen.
static unsigned MatchRegisterAltName(StringRef Name);

OperandMatchResultTy
VEAsmParser::tryParseRegister(unsigned &RegNo, SMLoc &StartLoc, SMLoc &EndLoc) {
  const AsmToken Tok = Parser.getTok();
  StartLoc = Tok.getLoc();
  EndLoc = Tok.getEndLoc();
  RegNo = 0;
  if (getLexer().getKind() != AsmToken::Percent)
    return MatchOperand_NoMatch;
  Parser.Lex();

  RegNo = parseRegisterName(&MatchRegisterName);
  if (RegNo == VE::NoRegister)
    RegNo = parseRegisterName(&MatchRegisterAltName);

  if (RegNo != VE::NoRegister) {
    Parser.Lex();
    return MatchOperand_Success;
  }

  getLexer().UnLex(Tok);
  return MatchOperand_NoMatch;
}

bool VEAsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                                   SMLoc NameLoc, OperandVector &Operands) {

  // First operand in MCInst is instruction mnemonic.
  Operands.push_back(VEOperand::CreateToken(Name, NameLoc));

  if (getLexer().isNot(AsmToken::EndOfStatement)) {
    // Read the first operand.
    if (parseOperand(Operands, Name) != MatchOperand_Success) {
      SMLoc Loc = getLexer().getLoc();
      return Error(Loc, "unexpected token");
    }

    while (getLexer().is(AsmToken::Comma)) {
      Parser.Lex(); // Eat the comma.
      // Parse and remember the operand.
      if (parseOperand(Operands, Name) != MatchOperand_Success) {
        SMLoc Loc = getLexer().getLoc();
        return Error(Loc, "unexpected token");
      }
    }
  }
  if (getLexer().isNot(AsmToken::EndOfStatement)) {
    SMLoc Loc = getLexer().getLoc();
    return Error(Loc, "unexpected token");
  }
  Parser.Lex(); // Consume the EndOfStatement.
  return false;
}

bool VEAsmParser::ParseDirective(AsmToken DirectiveID) {
  // Let the MC layer to handle other directives.
  return true;
}

OperandMatchResultTy VEAsmParser::parseMEMOperand(OperandVector &Operands) {
  LLVM_DEBUG(dbgs() << "parseMEMOperand\n");
  const AsmToken &Tok = Parser.getTok();
  SMLoc S = Tok.getLoc();
  SMLoc E = Tok.getEndLoc();
  // Parse ASX format
  //   disp
  //   disp(, base)
  //   disp(index)
  //   disp(index, base)
  //   (, base)
  //   (index)
  //   (index, base)

  std::unique_ptr<VEOperand> Offset;
  switch (getLexer().getKind()) {
  default:
    return MatchOperand_NoMatch;

  case AsmToken::Minus:
  case AsmToken::Integer:
  case AsmToken::Dot: {
    const MCExpr *EVal;
    if (!getParser().parseExpression(EVal, E))
      Offset = VEOperand::CreateImm(EVal, S, E);
    else
      return MatchOperand_NoMatch;
    break;
  }
  case AsmToken::LParen:
    // empty disp (= 0)
    Offset =
        VEOperand::CreateImm(MCConstantExpr::create(0, getContext()), S, E);
    break;
  }

  switch (getLexer().getKind()) {
  default:
    return MatchOperand_ParseFail;

  case AsmToken::EndOfStatement:
    Operands.push_back(VEOperand::MorphToMEMzii(
        MCConstantExpr::create(0, getContext()), std::move(Offset)));
    return MatchOperand_Success;

  case AsmToken::LParen:
    Parser.Lex(); // Eat the (
    break;
  }

  const MCExpr *IndexValue = nullptr;
  unsigned IndexReg = 0;

  switch (getLexer().getKind()) {
  default:
    if (ParseRegister(IndexReg, S, E))
      return MatchOperand_ParseFail;
    break;

  case AsmToken::Minus:
  case AsmToken::Integer:
  case AsmToken::Dot:
    if (getParser().parseExpression(IndexValue, E))
      return MatchOperand_ParseFail;
    break;

  case AsmToken::Comma:
    // empty index
    IndexValue = MCConstantExpr::create(0, getContext());
    break;
  }

  switch (getLexer().getKind()) {
  default:
    return MatchOperand_ParseFail;

  case AsmToken::RParen:
    Parser.Lex(); // Eat the )
    Operands.push_back(
        IndexValue ? VEOperand::MorphToMEMzii(IndexValue, std::move(Offset))
                   : VEOperand::MorphToMEMzri(IndexReg, std::move(Offset)));
    return MatchOperand_Success;

  case AsmToken::Comma:
    Parser.Lex(); // Eat the ,
    break;
  }

  unsigned BaseReg = 0;
  if (ParseRegister(BaseReg, S, E))
    return MatchOperand_ParseFail;

  if (!Parser.getTok().is(AsmToken::RParen))
    return MatchOperand_ParseFail;

  Parser.Lex(); // Eat the )
  Operands.push_back(
      IndexValue
          ? VEOperand::MorphToMEMrii(BaseReg, IndexValue, std::move(Offset))
          : VEOperand::MorphToMEMrri(BaseReg, IndexReg, std::move(Offset)));

  return MatchOperand_Success;
}

OperandMatchResultTy VEAsmParser::parseOperand(OperandVector &Operands,
                                               StringRef Mnemonic) {
  LLVM_DEBUG(dbgs() << "parseOperand\n");
  OperandMatchResultTy ResTy = MatchOperandParserImpl(Operands, Mnemonic);

  // If there wasn't a custom match, try the generic matcher below. Otherwise,
  // there was a match, but an error occurred, in which case, just return that
  // the operand parsing failed.
  if (ResTy == MatchOperand_Success || ResTy == MatchOperand_ParseFail)
    return ResTy;

  switch (getLexer().getKind()) {
  case AsmToken::LParen:
    // FIXME: Parsing "(" + %vreg + ", " + %vreg + ")"
    // FALLTHROUGH
  default: {
    std::unique_ptr<VEOperand> Op;
    ResTy = parseVEAsmOperand(Op);
    if (ResTy != MatchOperand_Success || !Op)
      return MatchOperand_ParseFail;

    // Push the parsed operand into the list of operands
    Operands.push_back(std::move(Op));

    if (!Parser.getTok().is(AsmToken::LParen))
      break;

    // FIXME: Parsing %vec-reg + "(" + %sclar-reg/number + ")"
    break;
  }
  }

  return MatchOperand_Success;
}

OperandMatchResultTy
VEAsmParser::parseVEAsmOperand(std::unique_ptr<VEOperand> &Op) {
  LLVM_DEBUG(dbgs() << "parseVEAsmOperand\n");
  SMLoc S = Parser.getTok().getLoc();
  SMLoc E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
  const MCExpr *EVal;

  Op = nullptr;
  switch (getLexer().getKind()) {
  default:
    break;

  case AsmToken::Percent:
    unsigned RegNo;
    if (tryParseRegister(RegNo, S, E) == MatchOperand_Success)
      Op = VEOperand::CreateReg(RegNo, S, E);
    break;

  case AsmToken::Minus:
  case AsmToken::Integer:
  case AsmToken::Dot:
    if (!getParser().parseExpression(EVal, E))
      Op = VEOperand::CreateImm(EVal, S, E);
    break;

  case AsmToken::Identifier: {
    StringRef Identifier;
    if (!getParser().parseIdentifier(Identifier)) {
      E = SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
      MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);

      const MCExpr *Res =
          MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, getContext());
      Op = VEOperand::CreateImm(Res, S, E);
    }
    break;
  }
  }
  return (Op) ? MatchOperand_Success : MatchOperand_ParseFail;
}

// Force static initialization.
extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeVEAsmParser() {
  RegisterMCAsmParser<VEAsmParser> A(getTheVETarget());
}

#define GET_REGISTER_MATCHER
#define GET_MATCHER_IMPLEMENTATION
#include "VEGenAsmMatcher.inc"