C++ MIToken::reset方法代码示例

static Cursor maybeLexMachineBasicBlock(Cursor C, MIToken &Token,
                                        ErrorCallbackType ErrorCallback) {
  bool IsReference = C.remaining().startswith("%bb.");
  if (!IsReference && !C.remaining().startswith("bb."))
    return None;
  auto Range = C;
  unsigned PrefixLength = IsReference ? 4 : 3;
  C.advance(PrefixLength); // Skip '%bb.' or 'bb.'
  if (!isdigit(C.peek())) {
    Token.reset(MIToken::Error, C.remaining());
    ErrorCallback(C.location(), "expected a number after '%bb.'");
    return C;
  }
  auto NumberRange = C;
  while (isdigit(C.peek()))
    C.advance();
  StringRef Number = NumberRange.upto(C);
  unsigned StringOffset = PrefixLength + Number.size(); // Drop '%bb.<id>'
  // TODO: The format bb.<id>.<irname> is supported only when it's not a
  // reference. Once we deprecate the format where the irname shows up, we
  // should only lex forward if it is a reference.
  if (C.peek() == '.') {
    C.advance(); // Skip '.'
    ++StringOffset;
    while (isIdentifierChar(C.peek()))
      C.advance();
  }
  Token.reset(IsReference ? MIToken::MachineBasicBlock
                          : MIToken::MachineBasicBlockLabel,
              Range.upto(C))
      .setIntegerValue(APSInt(Number))
      .setStringValue(Range.upto(C).drop_front(StringOffset));
  return C;
}

StringRef llvm::lexMIToken(StringRef Source, MIToken &Token,
                           ErrorCallbackType ErrorCallback) {
  auto C = skipComment(skipWhitespace(Cursor(Source)));
  if (C.isEOF()) {
    Token.reset(MIToken::Eof, C.remaining());
    return C.remaining();
  }

  if (Cursor R = maybeLexIntegerOrScalarType(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexMachineBasicBlock(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexIdentifier(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexJumpTableIndex(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexStackObject(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexFixedStackObject(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexConstantPoolItem(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexSubRegisterIndex(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexIRBlock(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexIRValue(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexRegister(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexGlobalValue(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexExternalSymbol(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexHexadecimalLiteral(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexNumericalLiteral(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexExlaim(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexSymbol(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexNewline(C, Token))
    return R.remaining();
  if (Cursor R = maybeLexEscapedIRValue(C, Token, ErrorCallback))
    return R.remaining();
  if (Cursor R = maybeLexStringConstant(C, Token, ErrorCallback))
    return R.remaining();

  Token.reset(MIToken::Error, C.remaining());
  ErrorCallback(C.location(),
                Twine("unexpected character '") + Twine(C.peek()) + "'");
  return C.remaining();
}

static Cursor maybeLexNewline(Cursor C, MIToken &Token) {
  if (!isNewlineChar(C.peek()))
    return None;
  auto Range = C;
  C.advance();
  Token.reset(MIToken::Newline, Range.upto(C));
  return C;
}

static Cursor maybeLexIntegerType(Cursor C, MIToken &Token) {
  if (C.peek() != 'i' || !isdigit(C.peek(1)))
    return None;
  auto Range = C;
  C.advance(); // Skip 'i'
  while (isdigit(C.peek()))
    C.advance();
  Token.reset(MIToken::IntegerType, Range.upto(C));
  return C;
}

static Cursor lexVirtualRegister(Cursor C, MIToken &Token) {
  auto Range = C;
  C.advance(); // Skip '%'
  auto NumberRange = C;
  while (isdigit(C.peek()))
    C.advance();
  Token.reset(MIToken::VirtualRegister, Range.upto(C))
      .setIntegerValue(APSInt(NumberRange.upto(C)));
  return C;
}

static Cursor maybeLexExlaim(Cursor C, MIToken &Token,
                             ErrorCallbackType ErrorCallback) {
  if (C.peek() != '!')
    return None;
  auto Range = C;
  C.advance(1);
  if (isdigit(C.peek()) || !isIdentifierChar(C.peek())) {
    Token.reset(MIToken::exclaim, Range.upto(C));
    return C;
  }
  while (isIdentifierChar(C.peek()))
    C.advance();
  StringRef StrVal = Range.upto(C);
  Token.reset(getMetadataKeywordKind(StrVal), StrVal);
  if (Token.isError())
    ErrorCallback(Token.location(),
                  "use of unknown metadata keyword '" + StrVal + "'");
  return C;
}

static Cursor maybeLexIdentifier(Cursor C, MIToken &Token) {
  if (!isalpha(C.peek()) && C.peek() != '_')
    return None;
  auto Range = C;
  while (isIdentifierChar(C.peek()))
    C.advance();
  auto Identifier = Range.upto(C);
  Token.reset(getIdentifierKind(Identifier), Identifier)
      .setStringValue(Identifier);
  return C;
}

static Cursor lexName(Cursor C, MIToken &Token, MIToken::TokenKind Type,
                      unsigned PrefixLength, ErrorCallbackType ErrorCallback) {
  auto Range = C;
  C.advance(PrefixLength);
  if (C.peek() == '"') {
    if (Cursor R = lexStringConstant(C, ErrorCallback)) {
      StringRef String = Range.upto(R);
      Token.reset(Type, String)
          .setOwnedStringValue(
              unescapeQuotedString(String.drop_front(PrefixLength)));
      return R;
    }
    Token.reset(MIToken::Error, Range.remaining());
    return Range;
  }
  while (isIdentifierChar(C.peek()))
    C.advance();
  Token.reset(Type, Range.upto(C))
      .setStringValue(Range.upto(C).drop_front(PrefixLength));
  return C;
}

static Cursor maybeLexHexadecimalLiteral(Cursor C, MIToken &Token) {
  if (C.peek() != '0' || (C.peek(1) != 'x' && C.peek(1) != 'X'))
    return None;
  Cursor Range = C;
  C.advance(2);
  unsigned PrefLen = 2;
  if (isValidHexFloatingPointPrefix(C.peek())) {
    C.advance();
    PrefLen++;
  }
  while (isxdigit(C.peek()))
    C.advance();
  StringRef StrVal = Range.upto(C);
  if (StrVal.size() <= PrefLen)
    return None;
  if (PrefLen == 2)
    Token.reset(MIToken::HexLiteral, Range.upto(C));
  else // It must be 3, which means that there was a floating-point prefix.
    Token.reset(MIToken::FloatingPointLiteral, Range.upto(C));
  return C;
}

static Cursor maybeLexHexFloatingPointLiteral(Cursor C, MIToken &Token) {
  if (C.peek() != '0' || C.peek(1) != 'x')
    return None;
  Cursor Range = C;
  C.advance(2); // Skip '0x'
  if (isValidHexFloatingPointPrefix(C.peek()))
    C.advance();
  while (isxdigit(C.peek()))
    C.advance();
  Token.reset(MIToken::FloatingPointLiteral, Range.upto(C));
  return C;
}

static Cursor maybeLexIndex(Cursor C, MIToken &Token, StringRef Rule,
                            MIToken::TokenKind Kind) {
  if (!C.remaining().startswith(Rule) || !isdigit(C.peek(Rule.size())))
    return None;
  auto Range = C;
  C.advance(Rule.size());
  auto NumberRange = C;
  while (isdigit(C.peek()))
    C.advance();
  Token.reset(Kind, Range.upto(C)).setIntegerValue(APSInt(NumberRange.upto(C)));
  return C;
}

static Cursor maybeLexRegister(Cursor C, MIToken &Token) {
  if (C.peek() != '%')
    return None;
  if (isdigit(C.peek(1)))
    return lexVirtualRegister(C, Token);
  auto Range = C;
  C.advance(); // Skip '%'
  while (isRegisterChar(C.peek()))
    C.advance();
  Token.reset(MIToken::NamedRegister, Range.upto(C))
      .setStringValue(Range.upto(C).drop_front(1)); // Drop the '%'
  return C;
}

static Cursor maybeLexEscapedIRValue(Cursor C, MIToken &Token,
                                     ErrorCallbackType ErrorCallback) {
  if (C.peek() != '`')
    return None;
  auto Range = C;
  C.advance();
  auto StrRange = C;
  while (C.peek() != '`') {
    if (C.isEOF() || isNewlineChar(C.peek())) {
      ErrorCallback(
          C.location(),
          "end of machine instruction reached before the closing '`'");
      Token.reset(MIToken::Error, Range.remaining());
      return C;
    }
    C.advance();
  }
  StringRef Value = StrRange.upto(C);
  C.advance();
  Token.reset(MIToken::QuotedIRValue, Range.upto(C)).setStringValue(Value);
  return C;
}

static Cursor maybeLexNumericalLiteral(Cursor C, MIToken &Token) {
  if (!isdigit(C.peek()) && (C.peek() != '-' || !isdigit(C.peek(1))))
    return None;
  auto Range = C;
  C.advance();
  while (isdigit(C.peek()))
    C.advance();
  if (C.peek() == '.')
    return lexFloatingPointLiteral(Range, C, Token);
  StringRef StrVal = Range.upto(C);
  Token.reset(MIToken::IntegerLiteral, StrVal).setIntegerValue(APSInt(StrVal));
  return C;
}

static Cursor maybeLexSymbol(Cursor C, MIToken &Token) {
  MIToken::TokenKind Kind;
  unsigned Length = 1;
  if (C.peek() == ':' && C.peek(1) == ':') {
    Kind = MIToken::coloncolon;
    Length = 2;
  } else
    Kind = symbolToken(C.peek());
  if (Kind == MIToken::Error)
    return None;
  auto Range = C;
  C.advance(Length);
  Token.reset(Kind, Range.upto(C));
  return C;
}