[MC] Add three-state parseDirective as a replacement for ParseDirective

[barannikov88]

Summary

Conventionally, parsing methods return false on success and true on
error. However, directive parsing methods need a third state: the
directive is not target specific. AsmParser::parseStatement detected
this case by using a fragile heuristic: if the target parser did not
consume any tokens, the directive is assumed to be not target-specific.

Some targets fail to follow the convention: they return success after
emitting an error or do not consume the entire line and return failure
on successful parsing. This was partially worked around by checking for
pending errors in parseStatement.

This patch tries to improve the situation by introducing parseDirective
method that returns ParseStatus -- three-state class. The new method
should eventually replace the old one returning bool.

ParseStatus is intentionally implicitly constructible from bool to allow
uses like return Error(Loc, "message"). It also has a potential to
replace OperandMatchResulTy as it is more convenient to use due to the
implicit construction from bool and more type safe.

[barannikov88]

Use the new method in WebAssembly target

[barannikov88]

llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp

700

@benshi001
There is something odd here. It handles cases like: .word foo - bar, emits some data, but then lets the generic parser handle the directive, which results in emitting more data. It also looks like this code path is not covered by object-emission tests. This was introduced in D38029.

[dschuff]

From the wasm side, this looks very nice!

[MaskRay]

llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp

700

Thank your for noting this.

Side note: I find that many target AsmParser have poor test coverage, and we need some attention.

[barannikov88]

llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp

700

I'll try to add a few tests by the end of the week

[barannikov88]

Update CSKY, Sparc and VE

[barannikov88]

llvm/include/llvm/MC/MCParser/MCTargetAsmParser.h

149

Does anyone have a preference for ParseResult over ParseStatus? I'm not sure which one is better.

[MaskRay]

Conventionally, parsing methods return false on success and true on error. However, directive parsing methods need a third state: [...]

Agreed. Thanks for cleaning up this.

ParseStatus is intentionally implicitly constructible from bool to allow uses like return Error(Loc, "message").

Nice!

It also has a potential to replace OperandMatchResulTy as it is more convenient to use due to the implicit construction from bool and more type safe.

Agreed. It looks like OperandMatchResulTy could be named more generically to support what ParseStatus does in this patch, but unfortunately this is difficult to change as the three enum members have 1000+ references...

llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp

700

Thanks! I need to amend my comment. Many target AsmParser have poor test coverage for error conditions.

(For some targets (e.g. CSKY), I think many non-error-condition code paths are not covered.)
For future in-tree targets, I guess we should pay more attention on their test coverage..

[MaskRay]

Minor suggestion to the summary: I think you can say that AsmParser::parseStatement has the fragile heuristic in the first paragraph, so that curious readers can find this important location immediately.
Otherwise due to changes to a lot of lib/Target code, they may not notice this quickly.

[barannikov88]

@MaskRay

Thank you for your comments,

In D154101#4461028, @MaskRay wrote:

Minor suggestion to the summary: I think you can say that AsmParser::parseStatement has the fragile heuristic in the first paragraph, so that curious readers can find this important location immediately.
Otherwise due to changes to a lot of lib/Target code, they may not notice this quickly.

I tried to improve the summary. If it is what your meant, please feel free to update it (looks like phabricator allows it).

In D154101#4461021, @MaskRay wrote:

It looks like OperandMatchResulTy could be named more generically to support what ParseStatus does in this patch, but unfortunately this is difficult to change as the three enum members have 1000+ references...

I think it could be handled gradually, but I haven't come with a migration plan yet. The most difficult part is tblgenerated methods such as MatchOperandParserImpl, which poison every operand parsing method they call with ParseStatus across all targets.

[MaskRay]

In D154101#4461449, @barannikov88 wrote:

@MaskRay

Thank you for your comments,

In D154101#4461028, @MaskRay wrote:

Minor suggestion to the summary: I think you can say that AsmParser::parseStatement has the fragile heuristic in the first paragraph, so that curious readers can find this important location immediately.
Otherwise due to changes to a lot of lib/Target code, they may not notice this quickly.

I tried to improve the summary. If it is what your meant, please feel free to update it (looks like phabricator allows it).

LG. Thanks!

In D154101#4461021, @MaskRay wrote:

It looks like OperandMatchResulTy could be named more generically to support what ParseStatus does in this patch, but unfortunately this is difficult to change as the three enum members have 1000+ references...

I think it could be handled gradually, but I haven't come with a migration plan yet. The most difficult part is tblgenerated methods such as MatchOperandParserImpl, which poison every operand parsing method they call with ParseStatus across all targets.

I haven't investigated closely but I guess some user-defined conversion function may help gradual migration.

[barannikov88]

Address llvm-ml failures

[barannikov88]

Add some tests

[MaskRay]

llvm/test/MC/MSP430/directive-byte-word-long-invalid.s

4

:[[#@LINE+3]]

[[@LINE]] is deprecated FileCheck syntax. I add a : before the line number just in case 3 matches 13, but I don't feel useful including the filename, so... Feel free to not adopt my leading : suggestion.

[barannikov88]

Add one more test and revert a couple of wrong changes

[barannikov88]

Use modern FileCheck syntax in new tests

[barannikov88]

llvm/test/MC/MSP430/directive-byte-word-long-invalid.s

4

:[[#@LINE+3]]

[[@LINE]] is deprecated FileCheck syntax. I add a : before the line number just in case 3 matches 13, but I don't feel useful including the filename, so... Feel free to not adopt my leading : suggestion.

I didn't know that it is deprecated, thanks for the heads-up. I used the new syntax in new tests, but kept the legacy syntax in the CSKY test for consistency with existing checks.

About the extra colon, I think it is not worth the effort ;) The chances that it will match a different line seem fairly low.

4

:[[#@LINE+3]]

[[@LINE]] is deprecated FileCheck syntax. I add a : before the line number just in case 3 matches 13, but I don't feel useful including the filename, so... Feel free to not adopt my leading : suggestion.

[barannikov88]

Drop outdated comment

[barannikov88]

Add a few more checks to WebAssemblyAsmParser

[barannikov88]

It is difficult to write good tests for WebAssembly directives becasue its parseDirective does not track column numbers. It needs larger refactoring, and I don't have time for this. I'll have to leave it to someone else.

[dschuff]

In D154101#4463955, @barannikov88 wrote:

It is difficult to write good tests for WebAssembly directives becasue its parseDirective does not track column numbers. It needs larger refactoring, and I don't have time for this. I'll have to leave it to someone else.

Understood, thanks for calling that out.

[barannikov88]

In D154101#4465229, @dschuff wrote:

In D154101#4463955, @barannikov88 wrote:

It is difficult to write good tests for WebAssembly directives becasue its parseDirective does not track column numbers. It needs larger refactoring, and I don't have time for this. I'll have to leave it to someone else.

Understood, thanks for calling that out.

Sorry, I was wrong about that. Here is an example of the current diagnostics:

/mnt/d/llvm-project/llvm/test/MC/WebAssembly/directives-invalid.s:13:18: error: Unknown type in .globaltype directive: i42
.globaltype sym, i42
                 ^

/mnt/d/llvm-project/llvm/test/MC/WebAssembly/directives-invalid.s:16:22: error: Expected identifier, got:

.globaltype sym, i32,
                     ^
/mnt/d/llvm-project/llvm/test/MC/WebAssembly/directives-invalid.s:16:22: error: Unknown type in .globaltype modifier:

.globaltype sym, i32,
                     ^

/mnt/d/llvm-project/llvm/test/MC/WebAssembly/directives-invalid.s:19:23: error: Unknown type in .globaltype modifier: unmutable
.globaltype sym, i32, unmutable
                      ^

        .globaltype     sym, i32, immutable
/mnt/d/llvm-project/llvm/test/MC/WebAssembly/directives-invalid.s:22:32: error: Expected EOL, instead got: ,
.globaltype sym, i32, immutable,
                               ^

That is, column numbers are printed correctly. Still, there is a room for improvement. If you're going to put this into your backlog, here are a few ideas:

• split parseDirective into several methods, one per directive;
• use parseComma(), parseOptionalToken(), parseEOL() instead of custom expect() and isNext();
• report errors via Error() with SMRange argument instead of "got: something" message;
• it is conventional to start diagnostic messages with a lowercase letter.

I'll add a few tests verifying the current behavior.

[barannikov88]

Add a few wasm tests

[kosarev]

llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp

520

Can we just remove this function? +Same for LoongArch, M68k, Xtensa.

[barannikov88]

llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp

520

I guess we can. The old method was pure virtual and had to be overridden, the new one does not have to.

[barannikov88]

llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp

520

fda24e86

llvm/include/llvm/MC/MCParser/MCTargetAsmParser.h

 struct ParseInstructionInfo {
   SmallVectorImpl<AsmRewrite> *AsmRewrites = nullptr;
 
   ParseInstructionInfo() = default;
   ParseInstructionInfo(SmallVectorImpl<AsmRewrite> *rewrites)
     : AsmRewrites(rewrites) {}
 };
 
+/// Ternary parse status returned by various parse* methods.
+class ParseStatus {
+  enum class StatusTy { Success, Failure, NoMatch } Status;
+
+public:
+#if __cplusplus >= 202002L
+  using enum StatusTy;
+#else
+  static constexpr StatusTy Success = StatusTy::Success;
+  static constexpr StatusTy Failure = StatusTy::Failure;
+  static constexpr StatusTy NoMatch = StatusTy::NoMatch;
+#endif
+
+  constexpr ParseStatus() : Status(NoMatch) {}
+
+  constexpr ParseStatus(StatusTy Status) : Status(Status) {}
+
+  constexpr ParseStatus(bool Error) : Status(Error ? Failure : Success) {}
+
+  template <typename T> constexpr ParseStatus(T) = delete;
+
+  constexpr bool isSuccess() const { return Status == StatusTy::Success; }
+  constexpr bool isFailure() const { return Status == StatusTy::Failure; }
+  constexpr bool isNoMatch() const { return Status == StatusTy::NoMatch; }
+};
+
 enum OperandMatchResultTy {
   MatchOperand_Success,  // operand matched successfully
   MatchOperand_NoMatch,  // operand did not match
   MatchOperand_ParseFail // operand matched but had errors
 };
 
 enum class DiagnosticPredicateTy {
   Match,
public:
   virtual bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                                 SMLoc NameLoc, OperandVector &Operands) = 0;
   virtual bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                                 AsmToken Token, OperandVector &Operands) {
     return ParseInstruction(Info, Name, Token.getLoc(), Operands);
   }
 
   /// ParseDirective - Parse a target specific assembler directive
+  /// This method is deprecated, use 'parseDirective' instead.
   ///
   /// The parser is positioned following the directive name.  The target
   /// specific directive parser should parse the entire directive doing or
   /// recording any target specific work, or return true and do nothing if the
   /// directive is not target specific. If the directive is specific for
   /// the target, the entire line is parsed up to and including the
   /// end-of-statement token and false is returned.
   ///
   /// \param DirectiveID - the identifier token of the directive.
-  virtual bool ParseDirective(AsmToken DirectiveID) = 0;
+  virtual bool ParseDirective(AsmToken DirectiveID) { return true; }
+
+  /// Parses a target-specific assembler directive.
+  ///
+  /// The parser is positioned following the directive name. The target-specific
+  /// directive parser should parse the entire directive doing or recording any
+  /// target-specific work, or emit an error. On success, the entire line should
+  /// be parsed up to and including the end-of-statement token. On failure, the
+  /// parser is not required to read to the end of the line. If the directive is
+  /// not target-specific, no tokens should be consumed and NoMatch is returned.
+  ///
+  /// \param DirectiveID - The token identifying the directive.
+  virtual ParseStatus parseDirective(AsmToken DirectiveID);
 
   /// MatchAndEmitInstruction - Recognize a series of operands of a parsed
   /// instruction as an actual MCInst and emit it to the specified MCStreamer.
   /// This returns false on success and returns true on failure to match.
   ///
   /// On failure, the target parser is responsible for emitting a diagnostic
   /// explaining the match failure.
   virtual bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,

llvm/lib/MC/MCParser/AsmParser.cpp

if (IDVal.startswith(".") && IDVal != ".") {
     //    (like the ELF parser) register themselves as extensions.
     // 3. The generic directive parser implemented by this class. These are
     //    all the directives that behave in a target and platform independent
     //    manner, or at least have a default behavior that's shared between
     //    all targets and platforms.
 
     getTargetParser().flushPendingInstructions(getStreamer());
 
-    SMLoc StartTokLoc = getTok().getLoc();
-    bool TPDirectiveReturn = getTargetParser().ParseDirective(ID);
-
-    if (hasPendingError())
-      return true;
-    // Currently the return value should be true if we are
-    // uninterested but as this is at odds with the standard parsing
-    // convention (return true = error) we have instances of a parsed
-    // directive that fails returning true as an error. Catch these
-    // cases as best as possible errors here.
-    if (TPDirectiveReturn && StartTokLoc != getTok().getLoc())
+    ParseStatus TPDirectiveReturn = getTargetParser().parseDirective(ID);
+    assert(TPDirectiveReturn.isFailure() == hasPendingError() &&
+           "Should only return Failure iff there was an error");
+    if (TPDirectiveReturn.isFailure())
       return true;
-    // Return if we did some parsing or believe we succeeded.
-    if (!TPDirectiveReturn || StartTokLoc != getTok().getLoc())
+    if (TPDirectiveReturn.isSuccess())
       return false;
 
     // Next, check the extension directive map to see if any extension has
     // registered itself to parse this directive.
     std::pair<MCAsmParserExtension *, DirectiveHandler> Handler =
         ExtensionDirectiveMap.lookup(IDVal);
     if (Handler.first)
       return (*Handler.second)(Handler.first, IDVal, IDLoc);

llvm/lib/MC/MCParser/MCTargetAsmParser.cpp

MCSubtargetInfo &MCTargetAsmParser::copySTI() {
   MCSubtargetInfo &STICopy = getContext().getSubtargetCopy(getSTI());
   STI = &STICopy;
   return STICopy;
 }
 
 const MCSubtargetInfo &MCTargetAsmParser::getSTI() const {
   return *STI;
 }
+
+ParseStatus MCTargetAsmParser::parseDirective(AsmToken DirectiveID) {
+  SMLoc StartTokLoc = getTok().getLoc();
+  // Delegate to ParseDirective by default for transition period. Once the
+  // transition is over, this method should just return NoMatch.
+  bool Res = ParseDirective(DirectiveID);
+
+  // Some targets erroneously report success after emitting an error.
+  if (getParser().hasPendingError())
+    return ParseStatus::Failure;
+
+  // ParseDirective returns true if there was an error or if the directive is
+  // not target-specific. Disambiguate the two cases by comparing position of
+  // the lexer before and after calling the method: if no tokens were consumed,
+  // there was no match, otherwise there was a failure.
+  if (!Res)
+    return ParseStatus::Success;
+  if (getTok().getLoc() != StartTokLoc)
+    return ParseStatus::Failure;
+  return ParseStatus::NoMatch;
+}

llvm/lib/MC/MCParser/MasmParser.cpp

if (DirKind != DK_NO_DIRECTIVE) {
     // First, check the extension directive map to see if any extension has
     // registered itself to parse this directive.
     std::pair<MCAsmParserExtension *, DirectiveHandler> Handler =
         ExtensionDirectiveMap.lookup(IDVal.lower());
     if (Handler.first)
       return (*Handler.second)(Handler.first, IDVal, IDLoc);
 
     // Next, let the target-specific assembly parser try.
-    SMLoc StartTokLoc = getTok().getLoc();
-    bool TPDirectiveReturn =
-        ID.is(AsmToken::Identifier) && getTargetParser().ParseDirective(ID);
-
-    if (hasPendingError())
-      return true;
-    // Currently the return value should be true if we are
-    // uninterested but as this is at odds with the standard parsing
-    // convention (return true = error) we have instances of a parsed
-    // directive that fails returning true as an error. Catch these
-    // cases as best as possible errors here.
-    if (TPDirectiveReturn && StartTokLoc != getTok().getLoc())
+    if (ID.isNot(AsmToken::Identifier))
+      return false;
+
+    ParseStatus TPDirectiveReturn = getTargetParser().parseDirective(ID);
+    assert(TPDirectiveReturn.isFailure() == hasPendingError() &&
+           "Should only return Failure iff there was an error");
+    if (TPDirectiveReturn.isFailure())
       return true;
-    // Return if we did some parsing or believe we succeeded.
-    if (!TPDirectiveReturn || StartTokLoc != getTok().getLoc())
+    if (TPDirectiveReturn.isSuccess())
       return false;
 
     // Finally, if no one else is interested in this directive, it must be
     // generic and familiar to this class.
     switch (DirKind) {
     default:
       break;
     case DK_ASCII:

llvm/lib/Target/AVR/AsmParser/AVRAsmParser.cpp

#include "AVRGenAsmMatcher.inc"
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
 
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
 
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
 
   OperandMatchResultTy parseMemriOperand(OperandVector &Operands);
 
   bool parseOperand(OperandVector &Operands, bool maybeReg);
   int parseRegisterName(unsigned (*matchFn)(StringRef));
   int parseRegisterName();
   int parseRegister(bool RestoreOnFailure = false);
   bool tryParseRegisterOperand(OperandVector &Operands);
unsigned toDREG(unsigned Reg, unsigned From = AVR::sub_lo) {
     return MRI->getMatchingSuperReg(Reg, From, Class);
   }
 
   bool emit(MCInst &Instruction, SMLoc const &Loc, MCStreamer &Out) const;
   bool invalidOperand(SMLoc const &Loc, OperandVector const &Operands,
                       uint64_t const &ErrorInfo);
   bool missingFeature(SMLoc const &Loc, uint64_t const &ErrorInfo);
 
-  bool parseLiteralValues(unsigned SizeInBytes, SMLoc L);
+  ParseStatus parseLiteralValues(unsigned SizeInBytes, SMLoc L);
 
 public:
   AVRAsmParser(const MCSubtargetInfo &STI, MCAsmParser &Parser,
                const MCInstrInfo &MII, const MCTargetOptions &Options)
       : MCTargetAsmParser(Options, STI, MII), STI(STI), Parser(Parser) {
     MCAsmParserExtension::Initialize(Parser);
     MRI = getContext().getRegisterInfo();
 
if (parseOperand(Operands, maybeReg)) {
       Parser.eatToEndOfStatement();
       return Error(Loc, "unexpected token in argument list");
     }
   }
   Parser.Lex(); // Consume the EndOfStatement
   return false;
 }
 
-bool AVRAsmParser::ParseDirective(llvm::AsmToken DirectiveID) {
+ParseStatus AVRAsmParser::parseDirective(llvm::AsmToken DirectiveID) {
   StringRef IDVal = DirectiveID.getIdentifier();
-  if (IDVal.lower() == ".long") {
-    parseLiteralValues(SIZE_LONG, DirectiveID.getLoc());
-  } else if (IDVal.lower() == ".word" || IDVal.lower() == ".short") {
-    parseLiteralValues(SIZE_WORD, DirectiveID.getLoc());
-  } else if (IDVal.lower() == ".byte") {
-    parseLiteralValues(1, DirectiveID.getLoc());
-  }
-  return true;
+  if (IDVal.lower() == ".long")
+    return parseLiteralValues(SIZE_LONG, DirectiveID.getLoc());
+  if (IDVal.lower() == ".word" || IDVal.lower() == ".short")
+    return parseLiteralValues(SIZE_WORD, DirectiveID.getLoc());
+  if (IDVal.lower() == ".byte")
+    return parseLiteralValues(1, DirectiveID.getLoc());
+  return ParseStatus::NoMatch;
 }
 
-bool AVRAsmParser::parseLiteralValues(unsigned SizeInBytes, SMLoc L) {
+ParseStatus AVRAsmParser::parseLiteralValues(unsigned SizeInBytes, SMLoc L) {
   MCAsmParser &Parser = getParser();
   AVRMCELFStreamer &AVRStreamer =
       static_cast<AVRMCELFStreamer &>(Parser.getStreamer());
   AsmToken Tokens[2];
   size_t ReadCount = Parser.getLexer().peekTokens(Tokens);
   if (ReadCount == 2 && Parser.getTok().getKind() == AsmToken::Identifier &&
       Tokens[0].getKind() == AsmToken::Minus &&
       Tokens[1].getKind() == AsmToken::Identifier) {
     MCSymbol *Symbol = getContext().getOrCreateSymbol(".text");
     AVRStreamer.emitValueForModiferKind(Symbol, SizeInBytes, L,
                                         AVRMCExpr::VK_AVR_None);
-    return false;
+    return ParseStatus::NoMatch;
   }
 
   if (Parser.getTok().getKind() == AsmToken::Identifier &&
       Parser.getLexer().peekTok().getKind() == AsmToken::LParen) {
     StringRef ModifierName = Parser.getTok().getString();
     AVRMCExpr::VariantKind ModifierKind =
         AVRMCExpr::getKindByName(ModifierName);
     if (ModifierKind != AVRMCExpr::VK_AVR_None) {
       Parser.Lex();
       Parser.Lex(); // Eat the modifier and parenthesis
     } else {
       return Error(Parser.getTok().getLoc(), "unknown modifier");
     }
     MCSymbol *Symbol =
         getContext().getOrCreateSymbol(Parser.getTok().getString());
     AVRStreamer.emitValueForModiferKind(Symbol, SizeInBytes, L, ModifierKind);
-    return false;
+    Lex(); // Eat the symbol name.
+    if (parseToken(AsmToken::RParen))
+      return ParseStatus::Failure;
+    return parseEOL();
   }
 
   auto parseOne = [&]() -> bool {
     const MCExpr *Value;
     if (Parser.parseExpression(Value))
       return true;
     Parser.getStreamer().emitValue(Value, SizeInBytes, L);
     return false;

llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp

class BPFAsmParser : public MCTargetAsmParser {
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
 
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
 
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
 
   // "=" is used as assignment operator for assembly statment, so can't be used
   // for symbol assignment.
   bool equalIsAsmAssignment() override { return false; }
   // "*" is used for dereferencing memory that it will be the start of
   // statement.
   bool starIsStartOfStatement() override { return true; }
 
if (getLexer().isNot(AsmToken::EndOfStatement)) {
     return Error(Loc, "unexpected token");
   }
 
   // Consume the EndOfStatement.
   getParser().Lex();
   return false;
 }
 
-bool BPFAsmParser::ParseDirective(AsmToken DirectiveID) { return true; }
+ParseStatus BPFAsmParser::parseDirective(AsmToken DirectiveID) {
+  return ParseStatus::NoMatch;
+}
 
 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeBPFAsmParser() {
   RegisterMCAsmParser<BPFAsmParser> X(getTheBPFTarget());
   RegisterMCAsmParser<BPFAsmParser> Y(getTheBPFleTarget());
   RegisterMCAsmParser<BPFAsmParser> Z(getTheBPFbeTarget());
 }

llvm/lib/Target/CSKY/AsmParser/CSKYAsmParser.cpp

bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                bool MatchingInlineAsm) override;
 
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
 
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
 
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
 
   // Helper to actually emit an instruction to the MCStreamer. Also, when
   // possible, compression of the instruction is performed.
   void emitToStreamer(MCStreamer &S, const MCInst &Inst);
 
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
 
OperandMatchResultTy CSKYAsmParser::tryParseRegister(MCRegister &RegNo,
 
   if (matchRegisterNameHelper(getSTI(), (MCRegister &)RegNo, Name))
     return MatchOperand_NoMatch;
 
   getParser().Lex(); // Eat identifier token.
   return MatchOperand_Success;
 }
 
-bool CSKYAsmParser::ParseDirective(AsmToken DirectiveID) {
-  // This returns false if this function recognizes the directive
-  // regardless of whether it is successfully handles or reports an
-  // error. Otherwise it returns true to give the generic parser a
-  // chance at recognizing it.
+ParseStatus CSKYAsmParser::parseDirective(AsmToken DirectiveID) {
   StringRef IDVal = DirectiveID.getString();
 
   if (IDVal == ".csky_attribute")
     return parseDirectiveAttribute();
 
-  return true;
+  return ParseStatus::NoMatch;
 }
 
 /// parseDirectiveAttribute
 ///  ::= .attribute expression ',' ( expression | "string" )
 bool CSKYAsmParser::parseDirectiveAttribute() {
   MCAsmParser &Parser = getParser();
   int64_t Tag;
   SMLoc TagLoc;
   TagLoc = Parser.getTok().getLoc();
   if (Parser.getTok().is(AsmToken::Identifier)) {
     StringRef Name = Parser.getTok().getIdentifier();
     std::optional<unsigned> Ret =
         ELFAttrs::attrTypeFromString(Name, CSKYAttrs::getCSKYAttributeTags());
-    if (!Ret) {
-      Error(TagLoc, "attribute name not recognised: " + Name);
-      return false;
-    }
+    if (!Ret)
+      return Error(TagLoc, "attribute name not recognised: " + Name);
     Tag = *Ret;
     Parser.Lex();
   } else {
     const MCExpr *AttrExpr;
 
     TagLoc = Parser.getTok().getLoc();
     if (Parser.parseExpression(AttrExpr))
       return true;
 
     const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(AttrExpr);
-    if (check(!CE, TagLoc, "expected numeric constant"))
-      return true;
+    if (!CE)
+      return Error(TagLoc, "expected numeric constant");
 
     Tag = CE->getValue();
   }
 
   if (Parser.parseComma())
     return true;
 
   StringRef StringValue;

llvm/lib/Target/Lanai/AsmParser/LanaiAsmParser.cpp

class LanaiAsmParser : public MCTargetAsmParser {
   unsigned parseAluOperator(bool PreOp, bool PostOp);
 
   // Split the mnemonic stripping conditional code and quantifiers
   StringRef splitMnemonic(StringRef Name, SMLoc NameLoc,
                           OperandVector *Operands);
 
   bool parsePrePost(StringRef Type, int *OffsetValue);
 
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
 
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
 
   bool parseRegister(MCRegister &RegNum, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
MorphToMemRegImm(unsigned BaseReg, std::unique_ptr<LanaiOperand> Op,
     Op->Mem.OffsetReg = 0;
     Op->Mem.Offset = Imm;
     return Op;
   }
 };
 
 } // end anonymous namespace
 
-bool LanaiAsmParser::ParseDirective(AsmToken /*DirectiveId*/) { return true; }
+ParseStatus LanaiAsmParser::parseDirective(AsmToken DirectiveID) {
+  return ParseStatus::NoMatch;
+}
 
 bool LanaiAsmParser::MatchAndEmitInstruction(SMLoc IdLoc, unsigned &Opcode,
                                              OperandVector &Operands,
                                              MCStreamer &Out,
                                              uint64_t &ErrorInfo,
                                              bool MatchingInlineAsm) {
   MCInst Inst;
   SMLoc ErrorLoc;

llvm/lib/Target/LoongArch/AsmParser/LoongArchAsmParser.cpp

class LoongArchAsmParser : public MCTargetAsmParser {
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
 
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
 
-  bool ParseDirective(AsmToken DirectiveID) override { return true; }
+  ParseStatus parseDirective(AsmToken DirectiveID) override {
+    return ParseStatus::NoMatch;
+  }
 
   bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                OperandVector &Operands, MCStreamer &Out,
                                uint64_t &ErrorInfo,
                                bool MatchingInlineAsm) override;
 
   unsigned checkTargetMatchPredicate(MCInst &Inst) override;
 

llvm/lib/Target/M68k/AsmParser/M68kAsmParser.cpp

public:
   unsigned validateTargetOperandClass(MCParsedAsmOperand &Op,
                                       unsigned Kind) override;
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
   bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                OperandVector &Operands, MCStreamer &Out,
                                uint64_t &ErrorInfo,
                                bool MatchingInlineAsm) override;
 };
 
 struct M68kMemOp {
   enum class Kind {
while (Parser.getTok().isNot(AsmToken::EndOfStatement)) {
     return Error(Loc, "unexpected token parsing operands");
   }
 
   // Eat EndOfStatement.
   Parser.Lex();
   return false;
 }
 
-bool M68kAsmParser::ParseDirective(AsmToken DirectiveID) { return true; }
+ParseStatus M68kAsmParser::parseDirective(AsmToken DirectiveID) {
+  return ParseStatus::NoMatch;
+}
 
 bool M68kAsmParser::invalidOperand(SMLoc const &Loc,
                                    OperandVector const &Operands,
                                    uint64_t const &ErrorInfo) {
   SMLoc ErrorLoc = Loc;
   char const *Diag = 0;
 
   if (ErrorInfo != ~0U) {

llvm/lib/Target/MSP430/AsmParser/MSP430AsmParser.cpp

class MSP430AsmParser : public MCTargetAsmParser {
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
 
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
 
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
   bool ParseDirectiveRefSym(AsmToken DirectiveID);
 
   unsigned validateTargetOperandClass(MCParsedAsmOperand &Op,
                                       unsigned Kind) override;
 
   bool parseJccInstruction(ParseInstructionInfo &Info, StringRef Name,
                            SMLoc NameLoc, OperandVector &Operands);
 
if (getLexer().isNot(AsmToken::EndOfStatement)) {
     return Error(Loc, "unexpected token");
   }
 
   getParser().Lex(); // Consume the EndOfStatement.
   return false;
 }
 
 bool MSP430AsmParser::ParseDirectiveRefSym(AsmToken DirectiveID) {
-    StringRef Name;
-    if (getParser().parseIdentifier(Name))
-      return TokError("expected identifier in directive");
 
-    MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
-    getStreamer().emitSymbolAttribute(Sym, MCSA_Global);
-    return false;
+  return parseEOL();
 }
 
-bool MSP430AsmParser::ParseDirective(AsmToken DirectiveID) {
+ParseStatus MSP430AsmParser::parseDirective(AsmToken DirectiveID) {
   StringRef IDVal = DirectiveID.getIdentifier();
-  if (IDVal.lower() == ".long") {
-    ParseLiteralValues(4, DirectiveID.getLoc());
-  } else if (IDVal.lower() == ".word" || IDVal.lower() == ".short") {
-    ParseLiteralValues(2, DirectiveID.getLoc());
-  } else if (IDVal.lower() == ".byte") {
-    ParseLiteralValues(1, DirectiveID.getLoc());
-  } else if (IDVal.lower() == ".refsym") {
+  if (IDVal.lower() == ".long")
+    return ParseLiteralValues(4, DirectiveID.getLoc());
+  if (IDVal.lower() == ".word" || IDVal.lower() == ".short")
+    return ParseLiteralValues(2, DirectiveID.getLoc());
+  if (IDVal.lower() == ".byte")
+    return ParseLiteralValues(1, DirectiveID.getLoc());
+  if (IDVal.lower() == ".refsym")
     return ParseDirectiveRefSym(DirectiveID);
-  }
-  return true;
+  return ParseStatus::NoMatch;
 }
 
 bool MSP430AsmParser::ParseOperand(OperandVector &Operands) {
   switch (getLexer().getKind()) {
     default: return true;
     case AsmToken::Identifier: {
       // try rN
       MCRegister RegNo;

llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp

bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                uint64_t &ErrorInfo,
                                bool MatchingInlineAsm) override;
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
 
   unsigned validateTargetOperandClass(MCParsedAsmOperand &Op,
                                       unsigned Kind) override;
 
   // Custom parse functions for Sparc specific operands.
   OperandMatchResultTy parseMEMOperand(OperandVector &Operands);
 
   OperandMatchResultTy parseMembarTag(OperandVector &Operands);
bool SparcAsmParser::ParseInstruction(ParseInstructionInfo &Info,
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     SMLoc Loc = getLexer().getLoc();
     return Error(Loc, "unexpected token");
   }
   Parser.Lex(); // Consume the EndOfStatement.
   return false;
 }
 
-bool SparcAsmParser::
-ParseDirective(AsmToken DirectiveID)
-{
+ParseStatus SparcAsmParser::parseDirective(AsmToken DirectiveID) {
   StringRef IDVal = DirectiveID.getString();
 
   if (IDVal == ".register") {
     // For now, ignore .register directive.
     Parser.eatToEndOfStatement();
-    return false;
+    return ParseStatus::Success;
   }
   if (IDVal == ".proc") {
     // For compatibility, ignore this directive.
     // (It's supposed to be an "optimization" in the Sun assembler)
     Parser.eatToEndOfStatement();
-    return false;
+    return ParseStatus::Success;
   }
 
   // Let the MC layer to handle other directives.
-  return true;
+  return ParseStatus::NoMatch;
 }
 
 OperandMatchResultTy
 SparcAsmParser::parseMEMOperand(OperandVector &Operands) {
   SMLoc S, E;
 
   std::unique_ptr<SparcOperand> LHS;
   if (parseSparcAsmOperand(LHS) != MatchOperand_Success)

llvm/lib/Target/SystemZ/AsmParser/SystemZAsmParser.cpp

SystemZAsmParser(const MCSubtargetInfo &sti, MCAsmParser &parser,
     // Alias the .word directive to .short.
     parser.addAliasForDirective(".word", ".short");
 
     // Initialize the set of available features.
     setAvailableFeatures(ComputeAvailableFeatures(getSTI().getFeatureBits()));
   }
 
   // Override MCTargetAsmParser.
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   bool ParseRegister(MCRegister &RegNo, SMLoc &StartLoc, SMLoc &EndLoc,
                      bool RestoreOnFailure);
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
SystemZAsmParser::parseAddress(OperandVector &Operands, MemoryKind MemKind,
   SMLoc EndLoc =
       SMLoc::getFromPointer(Parser.getTok().getLoc().getPointer() - 1);
   Operands.push_back(SystemZOperand::createMem(MemKind, RegKind, Base, Disp,
                                                Index, Length, LengthReg,
                                                StartLoc, EndLoc));
   return MatchOperand_Success;
 }
 
-bool SystemZAsmParser::ParseDirective(AsmToken DirectiveID) {
+ParseStatus SystemZAsmParser::parseDirective(AsmToken DirectiveID) {
   StringRef IDVal = DirectiveID.getIdentifier();
 
   if (IDVal == ".insn")
     return ParseDirectiveInsn(DirectiveID.getLoc());
   if (IDVal == ".machine")
     return ParseDirectiveMachine(DirectiveID.getLoc());
   if (IDVal.startswith(".gnu_attribute"))
     return ParseGNUAttribute(DirectiveID.getLoc());
 
-  return true;
+  return ParseStatus::NoMatch;
 }
 
 /// ParseDirectiveInsn
 /// ::= .insn [ format, encoding, (operands (, operands)*) ]
 bool SystemZAsmParser::ParseDirectiveInsn(SMLoc L) {
   MCAsmParser &Parser = getParser();
 
   // Expect instruction format as identifier.

 }
 
 /// ParseDirectiveMachine
 /// ::= .machine [ mcpu ]
 bool SystemZAsmParser::ParseDirectiveMachine(SMLoc L) {
   MCAsmParser &Parser = getParser();
   if (Parser.getTok().isNot(AsmToken::Identifier) &&
       Parser.getTok().isNot(AsmToken::String))
-    return Error(L, "unexpected token in '.machine' directive");
+    return TokError("unexpected token in '.machine' directive");
 
   StringRef CPU = Parser.getTok().getIdentifier();
   Parser.Lex();
-  if (parseToken(AsmToken::EndOfStatement))
-    return addErrorSuffix(" in '.machine' directive");
+  if (parseEOL())
+    return true;
 
   MCSubtargetInfo &STI = copySTI();
   STI.setDefaultFeatures(CPU, /*TuneCPU*/ CPU, "");
   setAvailableFeatures(ComputeAvailableFeatures(STI.getFeatureBits()));
 
   getTargetStreamer().emitMachine(CPU);
 
   return false;
 }
 
 bool SystemZAsmParser::ParseGNUAttribute(SMLoc L) {
   int64_t Tag;
   int64_t IntegerValue;
   if (!Parser.parseGNUAttribute(L, Tag, IntegerValue))
-    return false;
+    return Error(L, "malformed .gnu_attribute directive");
 
   // Tag_GNU_S390_ABI_Vector tag is '8' and can be 0, 1, or 2.
-  if (Tag != 8 || (IntegerValue < 0 || IntegerValue > 2)) {
-    Error(Parser.getTok().getLoc(),
-          "Unrecognized .gnu_attribute tag/value pair.");
-    return false;
-  }
+  if (Tag != 8 || (IntegerValue < 0 || IntegerValue > 2))
+    return Error(L, "unrecognized .gnu_attribute tag/value pair.");
 
   Parser.getStreamer().emitGNUAttribute(Tag, IntegerValue);
 
-  return true;
+  return parseEOL();
 }
 
 bool SystemZAsmParser::ParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                      SMLoc &EndLoc, bool RestoreOnFailure) {
   Register Reg;
   if (parseRegister(Reg, RestoreOnFailure))
     return true;
   if (Reg.Group == RegGR)

llvm/lib/Target/VE/AsmParser/VEAsmParser.cpp

bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                bool MatchingInlineAsm) override;
   bool parseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                      SMLoc &EndLoc) override;
   int parseRegisterName(unsigned (*matchFn)(StringRef));
   OperandMatchResultTy tryParseRegister(MCRegister &RegNo, SMLoc &StartLoc,
                                         SMLoc &EndLoc) override;
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
 
   unsigned validateTargetOperandClass(MCParsedAsmOperand &Op,
                                       unsigned Kind) override;
 
   // Custom parse functions for VE specific operands.
   OperandMatchResultTy parseMEMOperand(OperandVector &Operands);
   OperandMatchResultTy parseMEMAsOperand(OperandVector &Operands);
   OperandMatchResultTy parseCCOpOperand(OperandVector &Operands);
bool VEAsmParser::ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
   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) {
+ParseStatus VEAsmParser::parseDirective(AsmToken DirectiveID) {
   std::string IDVal = DirectiveID.getIdentifier().lower();
 
   // Defines VE specific directives.  Reference is "Vector Engine Assembly
   // Language Reference Manual":
   // https://www.hpc.nec/documents/sdk/pdfs/VectorEngine-as-manual-v1.3.pdf
 
   // The .word is 4 bytes long on VE.
   if (IDVal == ".word")
     return parseLiteralValues(4, DirectiveID.getLoc());
 
   // The .long is 8 bytes long on VE.
   if (IDVal == ".long")
     return parseLiteralValues(8, DirectiveID.getLoc());
 
   // The .llong is 8 bytes long on VE.
   if (IDVal == ".llong")
     return parseLiteralValues(8, DirectiveID.getLoc());
 
   // Let the MC layer to handle other directives.
-  return true;
+  return ParseStatus::NoMatch;
 }
 
 /// parseLiteralValues
 ///  ::= .word expression [, expression]*
 ///  ::= .long expression [, expression]*
 ///  ::= .llong expression [, expression]*
 bool VEAsmParser::parseLiteralValues(unsigned Size, SMLoc L) {
   auto parseOne = [&]() -> bool {

llvm/lib/Target/WebAssembly/AsmParser/WebAssemblyAsmParser.cpp

bool CheckDataSection() {
     }
     CurrentState = DataSection;
     return false;
   }
 
   // This function processes wasm-specific directives streamed to
   // WebAssemblyTargetStreamer, all others go to the generic parser
   // (see WasmAsmParser).
-  bool ParseDirective(AsmToken DirectiveID) override {
-    // This function has a really weird return value behavior that is different
-    // from all the other parsing functions:
-    // - return true && no tokens consumed -> don't know this directive / let
-    //   the generic parser handle it.
-    // - return true && tokens consumed -> a parsing error occurred.
-    // - return false -> processed this directive successfully.
+  ParseStatus parseDirective(AsmToken DirectiveID) override {
     assert(DirectiveID.getKind() == AsmToken::Identifier);
     auto &Out = getStreamer();
     auto &TOut =
         reinterpret_cast<WebAssemblyTargetStreamer &>(*Out.getTargetStreamer());
     auto &Ctx = Out.getContext();
 
-    // TODO: any time we return an error, at least one token must have been
-    // consumed, otherwise this will not signal an error to the caller.
     if (DirectiveID.getString() == ".globaltype") {
       auto SymName = expectIdent();
       if (SymName.empty())
-        return true;
+        return ParseStatus::Failure;
       if (expect(AsmToken::Comma, ","))
-        return true;
+        return ParseStatus::Failure;
       auto TypeTok = Lexer.getTok();
       auto TypeName = expectIdent();
       if (TypeName.empty())
-        return true;
+        return ParseStatus::Failure;
       auto Type = WebAssembly::parseType(TypeName);
       if (!Type)
         return error("Unknown type in .globaltype directive: ", TypeTok);
       // Optional mutable modifier. Default to mutable for historical reasons.
       // Ideally we would have gone with immutable as the default and used `mut`
       // as the modifier to match the `.wat` format.
       bool Mutable = true;
       if (isNext(AsmToken::Comma)) {
         TypeTok = Lexer.getTok();
         auto Id = expectIdent();
+        if (Id.empty())
+          return ParseStatus::Failure;
         if (Id == "immutable")
           Mutable = false;
         else
           // Should we also allow `mutable` and `mut` here for clarity?
           return error("Unknown type in .globaltype modifier: ", TypeTok);
       }
       // Now set this symbol with the correct type.
       auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
       WasmSym->setType(wasm::WASM_SYMBOL_TYPE_GLOBAL);
       WasmSym->setGlobalType(wasm::WasmGlobalType{uint8_t(*Type), Mutable});
       // And emit the directive again.
       TOut.emitGlobalType(WasmSym);
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".tabletype") {
       // .tabletype SYM, ELEMTYPE[, MINSIZE[, MAXSIZE]]
       auto SymName = expectIdent();
       if (SymName.empty())
-        return true;
+        return ParseStatus::Failure;
       if (expect(AsmToken::Comma, ","))
-        return true;
+        return ParseStatus::Failure;
 
       auto ElemTypeTok = Lexer.getTok();
       auto ElemTypeName = expectIdent();
       if (ElemTypeName.empty())
-        return true;
+        return ParseStatus::Failure;
       std::optional<wasm::ValType> ElemType =
           WebAssembly::parseType(ElemTypeName);
       if (!ElemType)
         return error("Unknown type in .tabletype directive: ", ElemTypeTok);
 
       wasm::WasmLimits Limits = DefaultLimits();
       if (isNext(AsmToken::Comma) && parseLimits(&Limits))
-        return true;
+        return ParseStatus::Failure;
 
       // Now that we have the name and table type, we can actually create the
       // symbol
       auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
       WasmSym->setType(wasm::WASM_SYMBOL_TYPE_TABLE);
       wasm::WasmTableType Type = {uint8_t(*ElemType), Limits};
       WasmSym->setTableType(Type);
       TOut.emitTableType(WasmSym);
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".functype") {
       // This code has to send things to the streamer similar to
       // WebAssemblyAsmPrinter::EmitFunctionBodyStart.
       // TODO: would be good to factor this into a common function, but the
       // assembler and backend really don't share any common code, and this code
       // parses the locals separately.
       auto SymName = expectIdent();
       if (SymName.empty())
-        return true;
+        return ParseStatus::Failure;
       auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
       if (WasmSym->isDefined()) {
         // We push 'Function' either when a label is parsed or a .functype
         // directive is parsed. The reason it is not easy to do this uniformly
         // in a single place is,
         // 1. We can't do this at label parsing time only because there are
         //    cases we don't have .functype directive before a function label,
         //    in which case we don't know if the label is a function at the time
         //    of parsing.
         // 2. We can't do this at .functype parsing time only because we want to
         //    detect a function started with a label and not ended correctly
         //    without encountering a .functype directive after the label.
         if (CurrentState != FunctionLabel) {
           // This .functype indicates a start of a function.
           if (ensureEmptyNestingStack())
-            return true;
+            return ParseStatus::Failure;
           push(Function);
         }
         CurrentState = FunctionStart;
         LastFunctionLabel = WasmSym;
       }
       auto Signature = std::make_unique<wasm::WasmSignature>();
       if (parseSignature(Signature.get()))
-        return true;
+        return ParseStatus::Failure;
       TC.funcDecl(*Signature);
       WasmSym->setSignature(Signature.get());
       addSignature(std::move(Signature));
       WasmSym->setType(wasm::WASM_SYMBOL_TYPE_FUNCTION);
       TOut.emitFunctionType(WasmSym);
       // TODO: backend also calls TOut.emitIndIdx, but that is not implemented.
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".export_name") {
       auto SymName = expectIdent();
       if (SymName.empty())
-        return true;
+        return ParseStatus::Failure;
       if (expect(AsmToken::Comma, ","))
-        return true;
+        return ParseStatus::Failure;
       auto ExportName = expectIdent();
+      if (ExportName.empty())
+        return ParseStatus::Failure;
       auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
       WasmSym->setExportName(storeName(ExportName));
       TOut.emitExportName(WasmSym, ExportName);
+      return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".import_module") {
       auto SymName = expectIdent();
       if (SymName.empty())
-        return true;
+        return ParseStatus::Failure;
       if (expect(AsmToken::Comma, ","))
-        return true;
+        return ParseStatus::Failure;
       auto ImportModule = expectIdent();
+      if (ImportModule.empty())
+        return ParseStatus::Failure;
       auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
       WasmSym->setImportModule(storeName(ImportModule));
       TOut.emitImportModule(WasmSym, ImportModule);
+      return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".import_name") {
       auto SymName = expectIdent();
       if (SymName.empty())
-        return true;
+        return ParseStatus::Failure;
       if (expect(AsmToken::Comma, ","))
-        return true;
+        return ParseStatus::Failure;
       auto ImportName = expectIdent();
+      if (ImportName.empty())
+        return ParseStatus::Failure;
       auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
       WasmSym->setImportName(storeName(ImportName));
       TOut.emitImportName(WasmSym, ImportName);
+      return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".tagtype") {
       auto SymName = expectIdent();
       if (SymName.empty())
-        return true;
+        return ParseStatus::Failure;
       auto WasmSym = cast<MCSymbolWasm>(Ctx.getOrCreateSymbol(SymName));
       auto Signature = std::make_unique<wasm::WasmSignature>();
       if (parseRegTypeList(Signature->Params))
-        return true;
+        return ParseStatus::Failure;
       WasmSym->setSignature(Signature.get());
       addSignature(std::move(Signature));
       WasmSym->setType(wasm::WASM_SYMBOL_TYPE_TAG);
       TOut.emitTagType(WasmSym);
       // TODO: backend also calls TOut.emitIndIdx, but that is not implemented.
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".local") {
       if (CurrentState != FunctionStart)
         return error(".local directive should follow the start of a function: ",
                      Lexer.getTok());
       SmallVector<wasm::ValType, 4> Locals;
       if (parseRegTypeList(Locals))
-        return true;
+        return ParseStatus::Failure;
       TC.localDecl(Locals);
       TOut.emitLocal(Locals);
       CurrentState = FunctionLocals;
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".int8" ||
         DirectiveID.getString() == ".int16" ||
         DirectiveID.getString() == ".int32" ||
         DirectiveID.getString() == ".int64") {
       if (CheckDataSection())
-        return true;
+        return ParseStatus::Failure;
       const MCExpr *Val;
       SMLoc End;
       if (Parser.parseExpression(Val, End))
         return error("Cannot parse .int expression: ", Lexer.getTok());
       size_t NumBits = 0;
       DirectiveID.getString().drop_front(4).getAsInteger(10, NumBits);
       Out.emitValue(Val, NumBits / 8, End);
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
     if (DirectiveID.getString() == ".asciz") {
       if (CheckDataSection())
-        return true;
+        return ParseStatus::Failure;
       std::string S;
       if (Parser.parseEscapedString(S))
         return error("Cannot parse string constant: ", Lexer.getTok());
       Out.emitBytes(StringRef(S.c_str(), S.length() + 1));
       return expect(AsmToken::EndOfStatement, "EOL");
     }
 
-    return true; // We didn't process this directive.
+    return ParseStatus::NoMatch; // We didn't process this directive.
   }
 
   // Called either when the first instruction is parsed of the function ends.
   void ensureLocals(MCStreamer &Out) {
     if (CurrentState == FunctionStart) {
       // We haven't seen a .local directive yet. The streamer requires locals to
       // be encoded as a prelude to the instructions, so emit an empty list of
       // locals here.

llvm/lib/Target/Xtensa/AsmParser/XtensaAsmParser.cpp

 
 struct XtensaOperand;
 
 class XtensaAsmParser : public MCTargetAsmParser {
 
   SMLoc getLoc() const { return getParser().getTok().getLoc(); }
 
   // Override MCTargetAsmParser.
-  bool ParseDirective(AsmToken DirectiveID) override;
+  ParseStatus parseDirective(AsmToken DirectiveID) override;
   bool parseRegister(MCRegister &RegNo,
                      SMLoc &StartLoc, SMLoc &EndLoc) override;
   bool ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                         SMLoc NameLoc, OperandVector &Operands) override;
   bool MatchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
                                OperandVector &Operands, MCStreamer &Out,
                                uint64_t &ErrorInfo,
                                bool MatchingInlineAsm) override;
if (getLexer().isNot(AsmToken::EndOfStatement)) {
     getParser().eatToEndOfStatement();
     return Error(Loc, "unexpected token");
   }
 
   getParser().Lex(); // Consume the EndOfStatement.
   return false;
 }
 
-bool XtensaAsmParser::ParseDirective(AsmToken DirectiveID) { return true; }
+ParseStatus XtensaAsmParser::parseDirective(AsmToken DirectiveID) {
+  return ParseStatus::NoMatch;
+}
 
 // Force static initialization.
 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeXtensaAsmParser() {
   RegisterMCAsmParser<XtensaAsmParser> X(getTheXtensaTarget());
 }

llvm/test/MC/CSKY/invalid-attribute.s

 ## Negative tests:
 ##  - Feed integer value to string type attribute.
 ##  - Feed string value to integer type attribute.
 ##  - Invalid arch string.
 
 # RUN: not llvm-mc %s -triple=csky -filetype=asm 2>&1 | FileCheck %s
 
+.csky_attribute CSKY_UNKNOWN
+# CHECK: [[@LINE-1]]:17: error: attribute name not recognised: CSKY_UNKNOWN
+
+.csky_attribute CSKY_ARCH_NAME
+# CHECK: [[@LINE-1]]:31: error: expected comma
+
+.csky_attribute CSKY_ISA_FLAGS
+# CHECK: [[@LINE-1]]:31: error: expected comma
+
+.csky_attribute CSKY_ARCH_NAME, "foo",
+# CHECK: [[@LINE-1]]:38: error: expected newline
+
+.csky_attribute CSKY_ISA_FLAGS, 42,
+# CHECK: [[@LINE-1]]:35: error: expected newline
+
 .csky_attribute CSKY_ARCH_NAME, "foo"
 # CHECK: [[@LINE-1]]:33: error: unknown arch name 
 
 .csky_attribute CSKY_CPU_NAME, "foo"
 # CHECK: [[@LINE-1]]:32: error: unknown cpu name
 
 .csky_attribute CSKY_DSP_VERSION, "1"
 # CHECK: [[@LINE-1]]:35: error: expected numeric constant

llvm/test/MC/MSP430/directive-byte-word-long-invalid.s

+# RUN: not llvm-mc -triple=msp430 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+3]]:6: error: unknown token in expression
+# CHECK: [[#@LINE+3]]:6: error: unknown token in expression
+# CHECK: [[#@LINE+3]]:6: error: unknown token in expression
+.byte, 42
+.word, 42
+.long, 42
+
+# CHECK: [[#@LINE+3]]:10: error: unknown token in expression
+# CHECK: [[#@LINE+3]]:10: error: unknown token in expression
+# CHECK: [[#@LINE+3]]:10: error: unknown token in expression
+.byte 42,
+.word 42,
+.long 42,
+
+# CHECK: [[#@LINE+3]]:10: error: unexpected token
+# CHECK: [[#@LINE+3]]:10: error: unexpected token
+# CHECK: [[#@LINE+3]]:10: error: unexpected token
+.byte 42 42
+.word 42 42
+.long 42 42

llvm/test/MC/MSP430/refsym-invalid.s

+# RUN: not llvm-mc -triple=msp430 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:8: error: expected identifier in directive
+.refsym
+
+# CHECK: [[#@LINE+1]]:9: error: expected identifier in directive
+.refsym 42
+
+# CHECK: [[#@LINE+1]]:12: error: expected newline
+.refsym sym,

llvm/test/MC/Sparc/sparc-directives.s

 ! RUN: llvm-mc %s -arch=sparc   -show-encoding | FileCheck %s --check-prefix=SPARC32
 ! RUN: llvm-mc %s -arch=sparcv9 -show-encoding | FileCheck %s --check-prefix=SPARC64
 
         ! '.proc' is documented to do nothing in the binutils assembler.
         ! so it should do nothing for clang either, i.e. not be an error.
-        .proc 1
+        .proc 1 x (
+
+        ! '.register' is currently ignored.
+        .register 8-)
 
         ! SPARC32: .byte 24
         ! SPARC64: .byte 24
         .byte 24
 
         ! SPARC32: .half 1024
         ! SPARC64: .half 1024
         ! SPARC32: .half 1024

llvm/test/MC/SystemZ/gnu-attributes-invalid.s

+# RUN: not llvm-mc -triple s390x %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:1: error: malformed .gnu_attribute directive
+.gnu_attribute tag, value
+
+# CHECK: [[#@LINE+1]]:1: error: unrecognized .gnu_attribute tag/value pair.
+.gnu_attribute 42, 8
+
+# CHECK: [[#@LINE+1]]:1: error: unrecognized .gnu_attribute tag/value pair.
+.gnu_attribute 8, 42
+
+# CHECK: [[#@LINE+1]]:20: error: expected newline
+.gnu_attribute 8, 1$

llvm/test/MC/SystemZ/machine-directive-invalid.s

+# RUN: not llvm-mc -triple=s390x %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:9: error: unexpected token in '.machine' directive
+.machine
+
+# CHECK: [[#@LINE+1]]:10: error: unexpected token in '.machine' directive
+.machine 42
+
+# CHECK: [[#@LINE+1]]:13: error: expected newline
+.machine z13+

llvm/test/MC/VE/data-size-error.s

 # CHECK:      data-size-error.s:12:6: error: out of range literal value
 # CHECK-NEXT: .int 0xff5588aaff
 # CHECK:      data-size-error.s:13:7: error: literal value out of range for directive
 # CHECK-NEXT: .long 0xff5588aadeadbeafde
 # CHECK:      data-size-error.s:14:7: error: literal value out of range for directive
 # CHECK-NEXT: .quad 0xff5588aadeadbeafde
 # CHECK:      data-size-error.s:15:8: error: literal value out of range for directive
 # CHECK-NEXT: .llong 0xff5588aadeadbeafde
+
+# CHECK: [[#@LINE+1]]:17: error: unknown token in expression
+.word 0xd0bb1e +
+
+# CHECK: [[#@LINE+1]]:16: error: unexpected token
+.long 0xd0bb1e =
+
+# CHECK: [[#@LINE+1]]:10: error: unexpected token
+.llong 2 0xd0bb1e

llvm/test/MC/WebAssembly/export-name-invalid.s

+# RUN: not llvm-mc -triple=wasm32 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:14: error: Expected identifier, got: 42
+.export_name 42
+
+# CHECK: [[#@LINE+1]]:17: error: Expected ,, instead got:
+.export_name foo
+
+# CHECK: [[#@LINE+1]]:18: error: Expected identifier, got:
+.export_name foo,
+
+# CHECK: [[#@LINE+1]]:22: error: Expected EOL, instead got: ,
+.export_name foo, bar,

llvm/test/MC/WebAssembly/functype-invalid.s

+# RUN: not llvm-mc -triple=wasm32 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:10: error: Expected identifier, got:
+.functype
+
+# CHECK: [[#@LINE+1]]:13: error: Expected (, instead got:
+.functype fn
+
+# CHECK: [[#@LINE+1]]:15: error: Expected ), instead got:
+.functype fn (
+
+# CHECK: [[#@LINE+1]]:15: error: unknown type: i42
+.functype fn (i42
+
+# CHECK: [[#@LINE+1]]:19: error: Expected ), instead got: i32
+.functype fn (i32 i32
+
+# CHECK: [[#@LINE+1]]:16: error: Expected ->, instead got:
+.functype fn ()
+
+# CHECK: [[#@LINE+1]]:17: error: Expected ->, instead got: <
+.functype fn () <- ()
+
+# CHECK: [[#@LINE+1]]:21: error: Expected ), instead got:
+.functype fn () -> (
+
+# CHECK: [[#@LINE+1]]:23: error: Expected EOL, instead got: ->
+.functype fn () -> () -> ()

llvm/test/MC/WebAssembly/globaltype-invalid.s

+# RUN: not llvm-mc -triple=wasm32 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:12: error: Expected identifier, got:
+.globaltype
+
+# CHECK: [[#@LINE+1]]:13: error: Expected identifier, got: 42
+.globaltype 42
+
+# CHECK: [[#@LINE+1]]:16: error: Expected ,, instead got:
+.globaltype sym
+
+# CHECK: [[#@LINE+1]]:17: error: Expected identifier, got:
+.globaltype sym,
+
+# CHECK: [[#@LINE+1]]:18: error: Expected identifier, got: 42
+.globaltype sym, 42
+
+# CHECK: [[#@LINE+1]]:18: error: Unknown type in .globaltype directive: i42
+.globaltype sym, i42
+
+# CHECK: [[#@LINE+1]]:22: error: Expected identifier, got:
+.globaltype sym, i32,
+
+# CHECK: [[#@LINE+1]]:23: error: Expected identifier, got: 42
+.globaltype sym, i32, 42
+
+# CHECK: [[#@LINE+1]]:23: error: Unknown type in .globaltype modifier: unmutable
+.globaltype sym, i32, unmutable
+
+# CHECK: [[#@LINE+1]]:32: error: Expected EOL, instead got: ,
+.globaltype sym, i32, immutable,

llvm/test/MC/WebAssembly/import-module-invalid.s

+# RUN: not llvm-mc -triple=wasm32 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:16: error: Expected identifier, got: 42
+.import_module 42
+
+# CHECK: [[#@LINE+1]]:19: error: Expected ,, instead got:
+.import_module foo
+
+# CHECK: [[#@LINE+1]]:20: error: Expected identifier, got:
+.import_module foo,
+
+# CHECK: [[#@LINE+1]]:24: error: Expected EOL, instead got: ,
+.import_module foo, bar,

llvm/test/MC/WebAssembly/import-name-invalid.s

+# RUN: not llvm-mc -triple=wasm32 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:14: error: Expected identifier, got: 42
+.import_name 42
+
+# CHECK: [[#@LINE+1]]:17: error: Expected ,, instead got:
+.import_name foo
+
+# CHECK: [[#@LINE+1]]:18: error: Expected identifier, got:
+.import_name foo,
+
+# CHECK: [[#@LINE+1]]:22: error: Expected EOL, instead got: ,
+.import_name foo, bar,

llvm/test/MC/WebAssembly/tabletype-invalid.s

+# RUN: not llvm-mc -triple=wasm32 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:11: error: Expected identifier, got:
+.tabletype
+
+# CHECK: [[#@LINE+1]]:12: error: Expected identifier, got: 42
+.tabletype 42
+
+# CHECK: [[#@LINE+1]]:15: error: Expected ,, instead got:
+.tabletype sym
+
+# CHECK: [[#@LINE+1]]:16: error: Expected identifier, got:
+.tabletype sym,
+
+# CHECK: [[#@LINE+1]]:17: error: Expected identifier, got: 42
+.tabletype sym, 42
+
+# CHECK: [[#@LINE+1]]:17: error: Unknown type in .tabletype directive: i42
+.tabletype sym, i42
+
+# CHECK: [[#@LINE+1]]:21: error: Expected integer constant, instead got:
+.tabletype sym, i32,
+
+# CHECK: [[#@LINE+1]]:25: error: Expected integer constant, instead got:
+.tabletype sym, i32, 42,
+
+# CHECK: [[#@LINE+1]]:28: error: Expected EOL, instead got: ,
+.tabletype sym, i32, 42, 42,

llvm/test/MC/WebAssembly/tagtype-invalid.s

+# RUN: not llvm-mc -triple=wasm32 %s 2>&1 | FileCheck %s
+
+# CHECK: [[#@LINE+1]]:10: error: Expected identifier, got: 42
+.tagtype 42
+
+# CHECK: [[#@LINE+1]]:13: error: Expected EOL, instead got: ,
+.tagtype foo, i32
+
+# CHECK: [[#@LINE+1]]:18: error: Expected EOL, instead got: pub
+.tagtype bar i32 pub