[MC][AArch64] Cleanup end-of-line parsing in AArch64 AsmParser.

[rengolin]

Small comments, otherwise, loos good.

lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp

4163

Shouldn't this be emitting an error?

4217

here too

[rengolin]

Ah, right. LGTM. Thanks!

lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp

 }
 
 /// tryParseRegister - Try to parse a register name. The token must be an
 /// Identifier when called, and if it is a register name the token is eaten and
 /// the register is added to the operand list.
 int AArch64AsmParser::tryParseRegister() {
   MCAsmParser &Parser = getParser();
   const AsmToken &Tok = Parser.getTok();
-  assert(Tok.is(AsmToken::Identifier) && "Token is not an Identifier");
+  if (Tok.isNot(AsmToken::Identifier))
+    return -1;
 
   std::string lowerCase = Tok.getString().lower();
   unsigned RegNum = matchRegisterNameAlias(lowerCase, false);
   // Also handle a few aliases of registers.
   if (RegNum == 0)
     RegNum = StringSwitch<unsigned>(lowerCase)
                  .Case("fp",  AArch64::FP)
                  .Case("lr",  AArch64::LR)

 
 /// tryParsePrefetch - Try to parse a prefetch operand.
 OperandMatchResultTy
 AArch64AsmParser::tryParsePrefetch(OperandVector &Operands) {
   MCAsmParser &Parser = getParser();
   SMLoc S = getLoc();
   const AsmToken &Tok = Parser.getTok();
   // Either an identifier for named values or a 5-bit immediate.
-  bool Hash = Tok.is(AsmToken::Hash);
-  if (Hash || Tok.is(AsmToken::Integer)) {
-    if (Hash)
-      Parser.Lex(); // Eat hash token.
+  // Eat optional hash.
+  parseOptionalToken(AsmToken::Hash);
+  if (Tok.is(AsmToken::Integer)) {
     const MCExpr *ImmVal;
     if (getParser().parseExpression(ImmVal))
       return MatchOperand_ParseFail;
 
     const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(ImmVal);
     if (!MCE) {
       TokError("immediate value expected for prefetch operand");
       return MatchOperand_ParseFail;
AArch64AsmParser::tryParseAdrpLabel(OperandVector &Operands) {
 
   return MatchOperand_Success;
 }
 
 /// tryParseAdrLabel - Parse and validate a source label for the ADR
 /// instruction.
 OperandMatchResultTy
 AArch64AsmParser::tryParseAdrLabel(OperandVector &Operands) {
-  MCAsmParser &Parser = getParser();
   SMLoc S = getLoc();
   const MCExpr *Expr;
 
-  if (Parser.getTok().is(AsmToken::Hash)) {
-    Parser.Lex(); // Eat hash token.
-  }
-
+  parseOptionalToken(AsmToken::Hash);
   if (getParser().parseExpression(Expr))
     return MatchOperand_ParseFail;
 
   SMLoc E = SMLoc::getFromPointer(getLoc().getPointer() - 1);
   Operands.push_back(AArch64Operand::CreateImm(Expr, S, E, getContext()));
 
   return MatchOperand_Success;
 }
 
 /// tryParseFPImm - A floating point immediate expression operand.
 OperandMatchResultTy
 AArch64AsmParser::tryParseFPImm(OperandVector &Operands) {
   MCAsmParser &Parser = getParser();
   SMLoc S = getLoc();
 
-  bool Hash = false;
-  if (Parser.getTok().is(AsmToken::Hash)) {
-    Parser.Lex(); // Eat '#'
-    Hash = true;
-  }
+  bool Hash = parseOptionalToken(AsmToken::Hash);
 
   // Handle negation, as that still comes through as a separate token.
-  bool isNegative = false;
-  if (Parser.getTok().is(AsmToken::Minus)) {
-    isNegative = true;
-    Parser.Lex();
-  }
+  bool isNegative = parseOptionalToken(AsmToken::Minus);
+
   const AsmToken &Tok = Parser.getTok();
   if (Tok.is(AsmToken::Real)) {
     APFloat RealVal(APFloat::IEEEdouble, Tok.getString());
     if (isNegative)
       RealVal.changeSign();
 
     uint64_t IntVal = RealVal.bitcastToAPInt().getZExtValue();
     int Val = AArch64_AM::getFP64Imm(APInt(64, IntVal));
if (!Parser.getTok().is(AsmToken::Identifier) ||
       !Parser.getTok().getIdentifier().equals_lower("lsl")) {
     Error(Parser.getTok().getLoc(), "only 'lsl #+N' valid after immediate");
     return MatchOperand_ParseFail;
   }
 
   // Eat 'lsl'
   Parser.Lex();
 
-  if (Parser.getTok().is(AsmToken::Hash)) {
-    Parser.Lex();
-  }
+  parseOptionalToken(AsmToken::Hash);
 
   if (Parser.getTok().isNot(AsmToken::Integer)) {
     Error(Parser.getTok().getLoc(), "only 'lsl #+N' valid after immediate");
     return MatchOperand_ParseFail;
   }
 
   int64_t ShiftAmount = Parser.getTok().getIntVal();
 
AArch64_AM::ShiftExtendType ShOp =
           .Default(AArch64_AM::InvalidShiftExtend);
 
   if (ShOp == AArch64_AM::InvalidShiftExtend)
     return MatchOperand_NoMatch;
 
   SMLoc S = Tok.getLoc();
   Parser.Lex();
 
-  bool Hash = getLexer().is(AsmToken::Hash);
+  bool Hash = parseOptionalToken(AsmToken::Hash);
+
   if (!Hash && getLexer().isNot(AsmToken::Integer)) {
     if (ShOp == AArch64_AM::LSL || ShOp == AArch64_AM::LSR ||
         ShOp == AArch64_AM::ASR || ShOp == AArch64_AM::ROR ||
         ShOp == AArch64_AM::MSL) {
       // We expect a number here.
       TokError("expected #imm after shift specifier");
       return MatchOperand_ParseFail;
     }
 
     // "extend" type operatoins don't need an immediate, #0 is implicit.
     SMLoc E = SMLoc::getFromPointer(getLoc().getPointer() - 1);
     Operands.push_back(
         AArch64Operand::CreateShiftExtend(ShOp, 0, false, S, E, getContext()));
     return MatchOperand_Success;
   }
 
-  if (Hash)
-    Parser.Lex(); // Eat the '#'.
-
   // Make sure we do actually have a number or a parenthesized expression.
   SMLoc E = Parser.getTok().getLoc();
   if (!Parser.getTok().is(AsmToken::Integer) &&
       !Parser.getTok().is(AsmToken::LParen)) {
     Error(E, "expected integer shift amount");
     return MatchOperand_ParseFail;
   }
 

 #undef SYS_ALIAS
 
   Parser.Lex(); // Eat operand.
 
   bool ExpectRegister = (Op.lower().find("all") == StringRef::npos);
   bool HasRegister = false;
 
   // Check for the optional register operand.
-  if (getLexer().is(AsmToken::Comma)) {
-    Parser.Lex(); // Eat comma.
-
+  if (parseOptionalToken(AsmToken::Comma)) {
     if (Tok.isNot(AsmToken::Identifier) || parseRegister(Operands))
       return TokError("expected register operand");
-
     HasRegister = true;
   }
 
-  if (getLexer().isNot(AsmToken::EndOfStatement)) {
-    return TokError("unexpected token in argument list");
-  }
+  if (parseToken(AsmToken::EndOfStatement, "unexpected token in argument list"))
+    return true;
 
   if (ExpectRegister && !HasRegister) {
     return TokError("specified " + Mnemonic + " op requires a register");
   }
   else if (!ExpectRegister && HasRegister) {
     return TokError("specified " + Mnemonic + " op does not use a register");
   }
 
-  Parser.Lex(); // Consume the EndOfStatement
   return false;
 }
 
 OperandMatchResultTy
 AArch64AsmParser::tryParseBarrierOperand(OperandVector &Operands) {
   MCAsmParser &Parser = getParser();
   const AsmToken &Tok = Parser.getTok();
 
   // Can be either a #imm style literal or an option name
-  bool Hash = Tok.is(AsmToken::Hash);
-  if (Hash || Tok.is(AsmToken::Integer)) {
+  parseOptionalToken(AsmToken::Hash);
+  if (Tok.is(AsmToken::Integer)) {
     // Immediate operand.
-    if (Hash)
-      Parser.Lex(); // Eat the '#'
     const MCExpr *ImmVal;
     SMLoc ExprLoc = getLoc();
     if (getParser().parseExpression(ImmVal))
       return MatchOperand_ParseFail;
     const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(ImmVal);
     if (!MCE) {
       Error(ExprLoc, "immediate value expected for barrier operand");
       return MatchOperand_ParseFail;
Operands.push_back(
       AArch64Operand::CreateReg(Reg, true, S, getLoc(), getContext()));
   // If there was an explicit qualifier, that goes on as a literal text
   // operand.
   if (!Kind.empty())
     Operands.push_back(
         AArch64Operand::CreateToken(Kind, false, S, getContext()));
 
   // If there is an index specifier following the register, parse that too.
-  if (Parser.getTok().is(AsmToken::LBrac)) {
-    SMLoc SIdx = getLoc();
-    Parser.Lex(); // Eat left bracket token.
-
+  if (parseOptionalToken(AsmToken::LBrac)) {
     const MCExpr *ImmVal;
     if (getParser().parseExpression(ImmVal))
       return false;
     const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(ImmVal);
     if (!MCE) {
       TokError("immediate value expected for vector index");
       return false;
     }
 
     SMLoc E = getLoc();
-    if (Parser.getTok().isNot(AsmToken::RBrac)) {
-      Error(E, "']' expected");
-      return false;
-    }
 
-    Parser.Lex(); // Eat right bracket token.
+    if (parseToken(AsmToken::RBrac, "']' expected"))
+      return false;
 
     Operands.push_back(AArch64Operand::CreateVectorIndex(MCE->getValue(), SIdx,
                                                          E, getContext()));
   }
 
   return false;
 }
 
bool AArch64AsmParser::parseRegister(OperandVector &Operands) {
   int64_t Reg = tryParseRegister();
   if (Reg == -1)
     return true;
   Operands.push_back(
       AArch64Operand::CreateReg(Reg, false, S, getLoc(), getContext()));
 
   // A small number of instructions (FMOVXDhighr, for example) have "[1]"
   // as a string token in the instruction itself.
-  if (getLexer().getKind() == AsmToken::LBrac) {
-    SMLoc LBracS = getLoc();
-    Parser.Lex();
-    const AsmToken &Tok = Parser.getTok();
+  if (parseOptionalToken(AsmToken::LBrac)) {
     if (Tok.is(AsmToken::Integer)) {
       SMLoc IntS = getLoc();
       int64_t Val = Tok.getIntVal();
       if (Val == 1) {
         Parser.Lex();
-        if (getLexer().getKind() == AsmToken::RBrac) {
-          SMLoc RBracS = getLoc();
-          Parser.Lex();
+        if (parseOptionalToken(AsmToken::RBrac)) {
           Operands.push_back(
               AArch64Operand::CreateToken("[", false, LBracS, getContext()));
           Operands.push_back(
               AArch64Operand::CreateToken("1", false, IntS, getContext()));
           Operands.push_back(
               AArch64Operand::CreateToken("]", false, RBracS, getContext()));
           return false;
         }
       }
     }
   }
 
   return false;
 }
 
 bool AArch64AsmParser::parseSymbolicImmVal(const MCExpr *&ImmVal) {
   MCAsmParser &Parser = getParser();
   bool HasELFModifier = false;
   AArch64MCExpr::VariantKind RefKind;
 
-  if (Parser.getTok().is(AsmToken::Colon)) {
-    Parser.Lex(); // Eat ':"
+  if (parseOptionalToken(AsmToken::Colon)) {
     HasELFModifier = true;
 
-    if (Parser.getTok().isNot(AsmToken::Identifier)) {
-      Error(Parser.getTok().getLoc(),
-            "expect relocation specifier in operand after ':'");
-      return true;
-    }
+    if (Parser.getTok().isNot(AsmToken::Identifier))
+      return TokError("expect relocation specifier in operand after ':'");
 
     std::string LowerCase = Parser.getTok().getIdentifier().lower();
     RefKind = StringSwitch<AArch64MCExpr::VariantKind>(LowerCase)
                   .Case("lo12", AArch64MCExpr::VK_LO12)
                   .Case("abs_g3", AArch64MCExpr::VK_ABS_G3)
                   .Case("abs_g2", AArch64MCExpr::VK_ABS_G2)
                   .Case("abs_g2_s", AArch64MCExpr::VK_ABS_G2_S)
                   .Case("abs_g2_nc", AArch64MCExpr::VK_ABS_G2_NC)
RefKind = StringSwitch<AArch64MCExpr::VariantKind>(LowerCase)
                   .Case("got_lo12", AArch64MCExpr::VK_GOT_LO12)
                   .Case("gottprel", AArch64MCExpr::VK_GOTTPREL_PAGE)
                   .Case("gottprel_lo12", AArch64MCExpr::VK_GOTTPREL_LO12_NC)
                   .Case("gottprel_g1", AArch64MCExpr::VK_GOTTPREL_G1)
                   .Case("gottprel_g0_nc", AArch64MCExpr::VK_GOTTPREL_G0_NC)
                   .Case("tlsdesc", AArch64MCExpr::VK_TLSDESC_PAGE)
                   .Default(AArch64MCExpr::VK_INVALID);
 
-    if (RefKind == AArch64MCExpr::VK_INVALID) {
-      Error(Parser.getTok().getLoc(),
-            "expect relocation specifier in operand after ':'");
-      return true;
-    }
+    if (RefKind == AArch64MCExpr::VK_INVALID)
+      return TokError("expect relocation specifier in operand after ':'");
 
     Parser.Lex(); // Eat identifier
 
-    if (Parser.getTok().isNot(AsmToken::Colon)) {
-      Error(Parser.getTok().getLoc(), "expect ':' after relocation specifier");
+    if (parseToken(AsmToken::Colon, "expect ':' after relocation specifier"))
       return true;
-    }
-    Parser.Lex(); // Eat ':'
-  }
 
   if (getParser().parseExpression(ImmVal))
     return true;
 
   if (HasELFModifier)
     ImmVal = AArch64MCExpr::create(ImmVal, RefKind, getContext());
 
   return false;
 }
 
 /// parseVectorList - Parse a vector list operand for AdvSIMD instructions.
 bool AArch64AsmParser::parseVectorList(OperandVector &Operands) {
   MCAsmParser &Parser = getParser();
   assert(Parser.getTok().is(AsmToken::LCurly) && "Token is not a Left Bracket");
   SMLoc S = getLoc();
   Parser.Lex(); // Eat left bracket token.
   StringRef Kind;
   int64_t FirstReg = tryMatchVectorRegister(Kind, true);
   if (FirstReg == -1)
     return true;
   int64_t PrevReg = FirstReg;
   unsigned Count = 1;
 
-  if (Parser.getTok().is(AsmToken::Minus)) {
-    Parser.Lex(); // Eat the minus.
-
+  if (parseOptionalToken(AsmToken::Minus)) {
     SMLoc Loc = getLoc();
     StringRef NextKind;
     int64_t Reg = tryMatchVectorRegister(NextKind, true);
     if (Reg == -1)
       return true;
     // Any Kind suffices must match on all regs in the list.
     if (Kind != NextKind)
       return Error(Loc, "mismatched register size suffix");
 
     unsigned Space = (PrevReg < Reg) ? (Reg - PrevReg) : (Reg + 32 - PrevReg);
 
     if (Space == 0 || Space > 3) {
       return Error(Loc, "invalid number of vectors");
     }
 
     Count += Space;
   }
   else {
-    while (Parser.getTok().is(AsmToken::Comma)) {
-      Parser.Lex(); // Eat the comma token.
-
+    while (parseOptionalToken(AsmToken::Comma)) {
       SMLoc Loc = getLoc();
       StringRef NextKind;
       int64_t Reg = tryMatchVectorRegister(NextKind, true);
       if (Reg == -1)
         return true;
       // Any Kind suffices must match on all regs in the list.
       if (Kind != NextKind)
         return Error(Loc, "mismatched register size suffix");
 
       // Registers must be incremental (with wraparound at 31)
       if (getContext().getRegisterInfo()->getEncodingValue(Reg) !=
           (getContext().getRegisterInfo()->getEncodingValue(PrevReg) + 1) % 32)
        return Error(Loc, "registers must be sequential");
 
       PrevReg = Reg;
       ++Count;
     }
   }
 
-  if (Parser.getTok().isNot(AsmToken::RCurly))
-    return Error(getLoc(), "'}' expected");
-  Parser.Lex(); // Eat the '}' token.
+  if (parseToken(AsmToken::RCurly, "'}' expected"))
+    return true;
 
   if (Count > 4)
     return Error(S, "invalid number of vectors");
 
   unsigned NumElements = 0;
   char ElementKind = 0;
   if (!Kind.empty())
     parseValidVectorKind(Kind, NumElements, ElementKind);
 
   Operands.push_back(AArch64Operand::CreateVectorList(
       FirstReg, Count, NumElements, ElementKind, S, getLoc(), getContext()));
 
   // If there is an index specifier following the list, parse that too.
-  if (Parser.getTok().is(AsmToken::LBrac)) {
-    SMLoc SIdx = getLoc();
-    Parser.Lex(); // Eat left bracket token.
-
+  if (parseOptionalToken(AsmToken::LBrac)) { // Eat left bracket token.
     const MCExpr *ImmVal;
     if (getParser().parseExpression(ImmVal))
       return false;
     const MCConstantExpr *MCE = dyn_cast<MCConstantExpr>(ImmVal);
     if (!MCE) {
       TokError("immediate value expected for vector index");
       return false;
     }
 
     SMLoc E = getLoc();
-    if (Parser.getTok().isNot(AsmToken::RBrac)) {
-      Error(E, "']' expected");
+    if (parseToken(AsmToken::RBrac, "']' expected"))
       return false;
-    }
-
-    Parser.Lex(); // Eat right bracket token.
 
     Operands.push_back(AArch64Operand::CreateVectorIndex(MCE->getValue(), SIdx,
                                                          E, getContext()));
   }
   return false;
 }
 
 OperandMatchResultTy
 AArch64AsmParser::tryParseGPR64sp0Operand(OperandVector &Operands) {
   MCAsmParser &Parser = getParser();
   const AsmToken &Tok = Parser.getTok();
   if (!Tok.is(AsmToken::Identifier))
     return MatchOperand_NoMatch;
 
   unsigned RegNum = matchRegisterNameAlias(Tok.getString().lower(), false);
 
   MCContext &Ctx = getContext();
   const MCRegisterInfo *RI = Ctx.getRegisterInfo();
   if (!RI->getRegClass(AArch64::GPR64spRegClassID).contains(RegNum))
     return MatchOperand_NoMatch;
 
   SMLoc S = getLoc();
   Parser.Lex(); // Eat register
 
-  if (Parser.getTok().isNot(AsmToken::Comma)) {
+  if (!parseOptionalToken(AsmToken::Comma)) {
     Operands.push_back(
         AArch64Operand::CreateReg(RegNum, false, S, getLoc(), Ctx));
     return MatchOperand_Success;
   }
-  Parser.Lex(); // Eat comma.
 
-  if (Parser.getTok().is(AsmToken::Hash))
-    Parser.Lex(); // Eat hash
+  parseOptionalToken(AsmToken::Hash);
 
   if (Parser.getTok().isNot(AsmToken::Integer)) {
     Error(getLoc(), "index must be absent or #0");
     return MatchOperand_ParseFail;
   }
 
   const MCExpr *ImmVal;
   if (Parser.parseExpression(ImmVal) || !isa<MCConstantExpr>(ImmVal) ||
if (GotShift != MatchOperand_NoMatch)
       return GotShift;
 
     // This was not a register so parse other operands that start with an
     // identifier (like labels) as expressions and create them as immediates.
     const MCExpr *IdVal;
     S = getLoc();
     if (getParser().parseExpression(IdVal))
       return true;
-
     E = SMLoc::getFromPointer(getLoc().getPointer() - 1);
     Operands.push_back(AArch64Operand::CreateImm(IdVal, S, E, getContext()));
     return false;
   }
   case AsmToken::Integer:
   case AsmToken::Real:
   case AsmToken::Hash: {
     // #42 -> immediate.
     S = getLoc();
-    if (getLexer().is(AsmToken::Hash))
-      Parser.Lex();
+
+    parseOptionalToken(AsmToken::Hash);
 
     // Parse a negative sign
     bool isNegative = false;
     if (Parser.getTok().is(AsmToken::Minus)) {
       isNegative = true;
       // We need to consume this token only when we have a Real, otherwise
       // we let parseSymbolicImmVal take care of it
       if (Parser.getLexer().peekTok().is(AsmToken::Real))
case AsmToken::Hash: {
     if (parseSymbolicImmVal(ImmVal))
       return true;
 
     E = SMLoc::getFromPointer(getLoc().getPointer() - 1);
     Operands.push_back(AArch64Operand::CreateImm(ImmVal, S, E, getContext()));
     return false;
   }
   case AsmToken::Equal: {
-    SMLoc Loc = Parser.getTok().getLoc();
+    SMLoc Loc = getLoc();
     if (Mnemonic != "ldr") // only parse for ldr pseudo (e.g. ldr r0, =val)
-      return Error(Loc, "unexpected token in operand");
+      return TokError("unexpected token in operand");
     Parser.Lex(); // Eat '='
     const MCExpr *SubExprVal;
     if (getParser().parseExpression(SubExprVal))
       return true;
 
     if (Operands.size() < 2 ||
         !static_cast<AArch64Operand &>(*Operands[1]).isReg())
       return Error(Loc, "Only valid when first operand is register");
if (Parser.getTok().is(AsmToken::Identifier) &&
     return true;
   }
 
   // Create the leading tokens for the mnemonic, split by '.' characters.
   size_t Start = 0, Next = Name.find('.');
   StringRef Head = Name.slice(Start, Next);
 
   // IC, DC, AT, and TLBI instructions are aliases for the SYS instruction.
-  if (Head == "ic" || Head == "dc" || Head == "at" || Head == "tlbi") {
-    bool IsError = parseSysAlias(Head, NameLoc, Operands);
-    return IsError;
-  }
+  if (Head == "ic" || Head == "dc" || Head == "at" || Head == "tlbi")
+    return parseSysAlias(Head, NameLoc, Operands);
 
   Operands.push_back(
       AArch64Operand::CreateToken(Head, false, NameLoc, getContext()));
   Mnemonic = Head;
 
   // Handle condition codes for a branch mnemonic
   if (Head == "b" && Next != StringRef::npos) {
     Start = Next;
bool AArch64AsmParser::ParseInstruction(ParseInstructionInfo &Info,
   // Read the remaining operands.
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     // Read the first operand.
     if (parseOperand(Operands, false, false)) {
       return true;
     }
 
     unsigned N = 2;
-    while (getLexer().is(AsmToken::Comma)) {
-      Parser.Lex(); // Eat the comma.
-
+    while (parseOptionalToken(AsmToken::Comma)) {
       // Parse and remember the operand.
       if (parseOperand(Operands, (N == 4 && condCodeFourthOperand) ||
                                      (N == 3 && condCodeThirdOperand) ||
                                      (N == 2 && condCodeSecondOperand),
                        condCodeSecondOperand || condCodeThirdOperand)) {
         return true;
       }
 
       // After successfully parsing some operands there are two special cases to
       // consider (i.e. notional operands not separated by commas). Both are due
       // to memory specifiers:
       //  + An RBrac will end an address for load/store/prefetch
       //  + An '!' will indicate a pre-indexed operation.
       //
       // It's someone else's responsibility to make sure these tokens are sane
       // in the given context!
-      if (Parser.getTok().is(AsmToken::RBrac)) {
-        SMLoc Loc = Parser.getTok().getLoc();
-        Operands.push_back(AArch64Operand::CreateToken("]", false, Loc,
-                                                       getContext()));
-        Parser.Lex();
-      }
 
-      if (Parser.getTok().is(AsmToken::Exclaim)) {
-        SMLoc Loc = Parser.getTok().getLoc();
-        Operands.push_back(AArch64Operand::CreateToken("!", false, Loc,
-                                                       getContext()));
-        Parser.Lex();
-      }
+      SMLoc RLoc = Parser.getTok().getLoc();
+      if (parseOptionalToken(AsmToken::RBrac))
+        Operands.push_back(
+            AArch64Operand::CreateToken("]", false, RLoc, getContext()));
+      SMLoc ELoc = Parser.getTok().getLoc();
+      if (parseOptionalToken(AsmToken::Exclaim))
+        Operands.push_back(
+            AArch64Operand::CreateToken("!", false, ELoc, getContext()));
 
       ++N;
     }
   }
 
-  if (getLexer().isNot(AsmToken::EndOfStatement)) {
-    SMLoc Loc = Parser.getTok().getLoc();
-    return Error(Loc, "unexpected token in argument list");
-  }
+  if (parseToken(AsmToken::EndOfStatement, "unexpected token in argument list"))
+    return true;
 
-  Parser.Lex(); // Consume the EndOfStatement
   return false;
 }
 
 // FIXME: This entire function is a giant hack to provide us with decent
 // operand range validation/diagnostics until TableGen/MC can be extended
 // to support autogeneration of this kind of validation.
 bool AArch64AsmParser::validateInstruction(MCInst &Inst,
                                          SmallVectorImpl<SMLoc> &Loc) {
bool AArch64AsmParser::ParseDirective(AsmToken DirectiveID) {
   const MCObjectFileInfo::Environment Format =
     getContext().getObjectFileInfo()->getObjectFileType();
   bool IsMachO = Format == MCObjectFileInfo::IsMachO;
   bool IsCOFF = Format == MCObjectFileInfo::IsCOFF;
 
   StringRef IDVal = DirectiveID.getIdentifier();
   SMLoc Loc = DirectiveID.getLoc();
   if (IDVal == ".arch")
-    return parseDirectiveArch(Loc);
-  if (IDVal == ".cpu")
-    return parseDirectiveCPU(Loc);
-  if (IDVal == ".hword")
-    return parseDirectiveWord(2, Loc);
-  if (IDVal == ".word")
-    return parseDirectiveWord(4, Loc);
-  if (IDVal == ".xword")
-    return parseDirectiveWord(8, Loc);
-  if (IDVal == ".tlsdesccall")
-    return parseDirectiveTLSDescCall(Loc);
-  if (IDVal == ".ltorg" || IDVal == ".pool")
-    return parseDirectiveLtorg(Loc);
-  if (IDVal == ".unreq")
-    return parseDirectiveUnreq(Loc);
-
-  if (!IsMachO && !IsCOFF) {
+    parseDirectiveArch(Loc);
+  else if (IDVal == ".cpu")
+    parseDirectiveCPU(Loc);
+  else if (IDVal == ".hword")
+    parseDirectiveWord(2, Loc);
+  else if (IDVal == ".word")
+    parseDirectiveWord(4, Loc);
+  else if (IDVal == ".xword")
+    parseDirectiveWord(8, Loc);
+  else if (IDVal == ".tlsdesccall")
+    parseDirectiveTLSDescCall(Loc);
+  else if (IDVal == ".ltorg" || IDVal == ".pool")
+    parseDirectiveLtorg(Loc);
+  else if (IDVal == ".unreq")
+    parseDirectiveUnreq(Loc);
+  else if (!IsMachO && !IsCOFF) {
     if (IDVal == ".inst")
-      return parseDirectiveInst(Loc);
-  }
-  if (IDVal == MCLOHDirectiveName())
-    return parseDirectiveLOH(IDVal, Loc);
-
+      parseDirectiveInst(Loc);
+    else
+      return true;
+  } else if (IDVal == MCLOHDirectiveName())
+    parseDirectiveLOH(IDVal, Loc);
+  else
     return true;
+  return false;
 }
 
 static const struct {
   const char *Name;
   const FeatureBitset Features;
 } ExtensionMap[] = {
   { "crc", {AArch64::FeatureCRC} },
   { "crypto", {AArch64::FeatureCrypto} },

 bool AArch64AsmParser::parseDirectiveArch(SMLoc L) {
   SMLoc ArchLoc = getLoc();
 
   StringRef Arch, ExtensionString;
   std::tie(Arch, ExtensionString) =
       getParser().parseStringToEndOfStatement().trim().split('+');
 
   unsigned ID = AArch64::parseArch(Arch);
-  if (ID == static_cast<unsigned>(AArch64::ArchKind::AK_INVALID)) {
-    Error(ArchLoc, "unknown arch name");
-    return false;
-  }
+  if (ID == static_cast<unsigned>(AArch64::ArchKind::AK_INVALID))
+    return Error(ArchLoc, "unknown arch name");
+
+  if (parseToken(AsmToken::EndOfStatement))
+    return true;
 
   // Get the architecture and extension features.
   std::vector<StringRef> AArch64Features;
   AArch64::getArchFeatures(ID, AArch64Features);
   AArch64::getExtensionFeatures(AArch64::getDefaultExtensions("generic", ID),
                                 AArch64Features);
 
   MCSubtargetInfo &STI = copySTI();

 ///   ::= .cpu id
 bool AArch64AsmParser::parseDirectiveCPU(SMLoc L) {
   SMLoc CPULoc = getLoc();
 
   StringRef CPU, ExtensionString;
   std::tie(CPU, ExtensionString) =
       getParser().parseStringToEndOfStatement().trim().split('+');
 
+  if (parseToken(AsmToken::EndOfStatement))
+    return true;
+
   SmallVector<StringRef, 4> RequestedExtensions;
   if (!ExtensionString.empty())
     ExtensionString.split(RequestedExtensions, '+');
 
   // FIXME This is using tablegen data, but should be moved to ARMTargetParser
   // once that is tablegen'ed
   if (!getSTI().isCPUStringValid(CPU)) {
     Error(CPULoc, "unknown CPU name");
for (auto Name : RequestedExtensions) {
     }
   }
   return false;
 }
 
 /// parseDirectiveWord
 ///  ::= .word [ expression (, expression)* ]
 bool AArch64AsmParser::parseDirectiveWord(unsigned Size, SMLoc L) {
-  MCAsmParser &Parser = getParser();
-  if (getLexer().isNot(AsmToken::EndOfStatement)) {
-    for (;;) {
-      const MCExpr *Value;
-      if (getParser().parseExpression(Value))
-        return true;
-
-      getParser().getStreamer().EmitValue(Value, Size, L);
+  auto parseOp = [&]() -> bool {
+    return false;
+  };
 
-      if (getLexer().is(AsmToken::EndOfStatement))
-        break;
-
-      // FIXME: Improve diagnostic.
-      if (getLexer().isNot(AsmToken::Comma))
-        return Error(L, "unexpected token in directive");
-      Parser.Lex();
-    }
-  }
-
-  Parser.Lex();
+  if (parseMany(parseOp))
+    return true;
   return false;
 }
 
 /// parseDirectiveInst
 ///  ::= .inst opcode [, ...]
 bool AArch64AsmParser::parseDirectiveInst(SMLoc Loc) {
-  MCAsmParser &Parser = getParser();
-  if (getLexer().is(AsmToken::EndOfStatement)) {
-    Error(Loc, "expected expression following directive");
-    return false;
-  }
+  if (getLexer().is(AsmToken::EndOfStatement))
+    return Error(Loc, "expected expression following '.inst' directive");
 
-  for (;;) {
+  auto parseOp = [&]() -> bool {
+    SMLoc L = getLoc();
     const MCExpr *Expr;
-
-    if (getParser().parseExpression(Expr)) {
-      Error(Loc, "expected expression");
-      return false;
-    }
-
+    if (check(getParser().parseExpression(Expr), L, "expected expression"))
+      return true;
     const MCConstantExpr *Value = dyn_cast_or_null<MCConstantExpr>(Expr);
-    if (!Value) {
-      Error(Loc, "expected constant expression");
-      return false;
-    }
-
+    if (check(!Value, L, "expected constant expression"))
+      return true;
     getTargetStreamer().emitInst(Value->getValue());
-
-    if (getLexer().is(AsmToken::EndOfStatement))
-      break;
-
-    if (getLexer().isNot(AsmToken::Comma)) {
-      Error(Loc, "unexpected token in directive");
-      return false;
-    }
-
-    Parser.Lex(); // Eat comma.
-  }
+  };
 
-  Parser.Lex();
+  if (parseMany(parseOp))
+    return addErrorSuffix(" in '.inst' directive");
   return false;
 }
 
 // parseDirectiveTLSDescCall:
 //   ::= .tlsdesccall symbol
 bool AArch64AsmParser::parseDirectiveTLSDescCall(SMLoc L) {
   StringRef Name;
-  if (getParser().parseIdentifier(Name))
-    return Error(L, "expected symbol after directive");
+  if (check(getParser().parseIdentifier(Name), L,
+            "expected symbol after directive") ||
+      parseToken(AsmToken::EndOfStatement))
+    return true;
 
   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
   const MCExpr *Expr = MCSymbolRefExpr::create(Sym, getContext());
   Expr = AArch64MCExpr::create(Expr, AArch64MCExpr::VK_TLSDESC, getContext());
 
   MCInst Inst;
   Inst.setOpcode(AArch64::TLSDESCCALL);
   Inst.addOperand(MCOperand::createExpr(Expr));
 
   getParser().getStreamer().EmitInstruction(Inst, getSTI());
   return false;
 }
 
 /// ::= .loh <lohName | lohId> label1, ..., labelN
 /// The number of arguments depends on the loh identifier.
 bool AArch64AsmParser::parseDirectiveLOH(StringRef IDVal, SMLoc Loc) {
   MCLOHType Kind;
   if (getParser().getTok().isNot(AsmToken::Identifier)) {
     if (getParser().getTok().isNot(AsmToken::Integer))
       return TokError("expected an identifier or a number in directive");
     // We successfully get a numeric value for the identifier.
     // Check if it is valid.
     int64_t Id = getParser().getTok().getIntVal();
-    if (Id <= -1U && !isValidMCLOHType(Id)) {
-      TokError("invalid numeric identifier in directive");
-      return false;
-    }
+    if (Id <= -1U && !isValidMCLOHType(Id))
+      return TokError("invalid numeric identifier in directive");
     Kind = (MCLOHType)Id;
   } else {
     StringRef Name = getTok().getIdentifier();
     // We successfully parse an identifier.
     // Check if it is a recognized one.
     int Id = MCLOHNameToId(Name);
 
     if (Id == -1)
bool AArch64AsmParser::parseDirectiveLOH(StringRef IDVal, SMLoc Loc) {
   for (int Idx = 0; Idx < NbArgs; ++Idx) {
     StringRef Name;
     if (getParser().parseIdentifier(Name))
       return TokError("expected identifier in directive");
     Args.push_back(getContext().getOrCreateSymbol(Name));
 
     if (Idx + 1 == NbArgs)
       break;
-    if (getLexer().isNot(AsmToken::Comma))
-      return TokError("unexpected token in '" + Twine(IDVal) + "' directive");
-    Lex();
+    if (parseToken(AsmToken::Comma,
+                   "unexpected token in '" + Twine(IDVal) + "' directive"))
+      return true;
   }
-  if (getLexer().isNot(AsmToken::EndOfStatement))
-    return TokError("unexpected token in '" + Twine(IDVal) + "' directive");
+  if (parseToken(AsmToken::EndOfStatement,
+                 "unexpected token in '" + Twine(IDVal) + "' directive"))
+    return true;
 
   getStreamer().EmitLOHDirective((MCLOHType)Kind, Args);
   return false;
 }
 
 /// parseDirectiveLtorg
 ///  ::= .ltorg | .pool
 bool AArch64AsmParser::parseDirectiveLtorg(SMLoc L) {
+  if (parseToken(AsmToken::EndOfStatement, "unexpected token in directive"))
+    return true;
   getTargetStreamer().emitCurrentConstantPool();
   return false;
 }
 
 /// parseDirectiveReq
 ///  ::= name .req registername
 bool AArch64AsmParser::parseDirectiveReq(StringRef Name, SMLoc L) {
   MCAsmParser &Parser = getParser();
if (!Kind.empty())
       return Error(SRegLoc, "vector register without type specifier expected");
     IsVector = true;
   }
 
   if (RegNum == static_cast<unsigned>(-1))
     return Error(SRegLoc, "register name or alias expected");
 
   // Shouldn't be anything else.
-  if (Parser.getTok().isNot(AsmToken::EndOfStatement))
-    return Error(Parser.getTok().getLoc(),
-                 "unexpected input in .req directive");
-
-  Parser.Lex(); // Consume the EndOfStatement
+  if (parseToken(AsmToken::EndOfStatement,
+                 "unexpected input in .req directive"))
+    return true;
 
   auto pair = std::make_pair(IsVector, RegNum);
   if (RegisterReqs.insert(std::make_pair(Name, pair)).first->second != pair)
     Warning(L, "ignoring redefinition of register alias '" + Name + "'");
 
   return false;
 }
 
 /// parseDirectiveUneq
 ///  ::= .unreq registername
 bool AArch64AsmParser::parseDirectiveUnreq(SMLoc L) {
   MCAsmParser &Parser = getParser();
-  if (Parser.getTok().isNot(AsmToken::Identifier)) {
-    Error(Parser.getTok().getLoc(), "unexpected input in .unreq directive.");
-    return false;
-  }
+  if (getTok().isNot(AsmToken::Identifier))
+    return TokError("unexpected input in .unreq directive.");
   RegisterReqs.erase(Parser.getTok().getIdentifier().lower());
   Parser.Lex(); // Eat the identifier.
+  if (parseToken(AsmToken::EndOfStatement))
+    return addErrorSuffix("in '.unreq' directive");
   return false;
 }
 
 bool
 AArch64AsmParser::classifySymbolRef(const MCExpr *Expr,
                                     AArch64MCExpr::VariantKind &ELFRefKind,
                                     MCSymbolRefExpr::VariantKind &DarwinRefKind,
                                     int64_t &Addend) {

test/MC/AArch64/inst-directive-diagnostic.s

 // RUN: not llvm-mc %s -triple=aarch64-none-linux-gnu -filetype asm -o - 2>&1 \
 // RUN:   | FileCheck -check-prefix CHECK-ERROR %s
 
   .align 2
   .global diagnostics
   .type diagnostics,%function
 diagnostics:
 .Label:
     .inst
-// CHECK-ERROR: expected expression following directive
+// CHECK: [[@LINE-1]]:5: error: expected expression following '.inst' directive 
 
     .inst 0x5e104020,
-// CHECK-ERROR: expected expression
+// CHECK: [[@LINE-1]]:22: error: unknown token in expression in '.inst' directive
 
     .inst .Label
-// CHECK-ERROR: expected constant expression
+// CHECK: [[@LINE-1]]:11: error: expected constant expression in '.inst' directive
 
     .inst 0x5e104020 0x5e104020
-// CHECK-ERROR: unexpected token in directive
+// CHECK: [[@LINE-1]]:22: error: unexpected token in '.inst' directive
 
 // CHECK-ERROR-NOT: unexpected token at start of statement  
+