[llvm] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

llvm/include/llvm/AsmParser/LLParser.h

@@ -181,7 +181,7 @@ namespace llvm {
           BlockAddressPFS(nullptr) {}
     bool Run(
         bool UpgradeDebugInfo, DataLayoutCallbackTy DataLayoutCallback =
-                                   [](StringRef) { return None; });
+                                   [](StringRef) { return std::nullopt; });
 
     bool parseStandaloneConstantValue(Constant *&C, const SlotMapping *Slots);
 

llvm/include/llvm/AsmParser/Parser.h

@@ -87,7 +87,9 @@ struct ParsedModuleAndIndex {
 ParsedModuleAndIndex parseAssemblyFileWithIndex(
     StringRef Filename, SMDiagnostic &Err, LLVMContext &Context,
     SlotMapping *Slots = nullptr,
-    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) { return None; });
+    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) {
+      return std::nullopt;
+    });
 
 /// Only for use in llvm-as for testing; this does not produce a valid module.
 ParsedModuleAndIndex parseAssemblyFileWithIndexNoUpgradeDebugInfo(
@@ -126,7 +128,9 @@ parseSummaryIndexAssemblyString(StringRef AsmString, SMDiagnostic &Err);
 std::unique_ptr<Module> parseAssembly(
     MemoryBufferRef F, SMDiagnostic &Err, LLVMContext &Context,
     SlotMapping *Slots = nullptr,
-    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) { return None; });
+    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) {
+      return std::nullopt;
+    });
 
 /// Parse LLVM Assembly including the summary index from a MemoryBuffer.
 ///
@@ -166,7 +170,9 @@ parseSummaryIndexAssembly(MemoryBufferRef F, SMDiagnostic &Err);
 bool parseAssemblyInto(
     MemoryBufferRef F, Module *M, ModuleSummaryIndex *Index, SMDiagnostic &Err,
     SlotMapping *Slots = nullptr,
-    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) { return None; });
+    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) {
+      return std::nullopt;
+    });
 
 /// Parse a type and a constant value in the given string.
 ///

llvm/include/llvm/BinaryFormat/AMDGPUMetadataVerifier.h

@@ -50,7 +50,7 @@ class MetadataVerifier {
   bool verifyInteger(msgpack::DocNode &Node);
   bool verifyArray(msgpack::DocNode &Node,
                    function_ref<bool(msgpack::DocNode &)> verifyNode,
-                   Optional<size_t> Size = None);
+                   Optional<size_t> Size = std::nullopt);
   bool verifyEntry(msgpack::MapDocNode &MapNode, StringRef Key, bool Required,
                    function_ref<bool(msgpack::DocNode &)> verifyNode);
   bool

llvm/include/llvm/BinaryFormat/Dwarf.def

@@ -916,7 +916,7 @@ HANDLE_DW_LANG(0x0023, Fortran08, 1, 5, DWARF)
 HANDLE_DW_LANG(0x0024, RenderScript, 0, 5, DWARF)
 HANDLE_DW_LANG(0x0025, BLISS, 0, 5, DWARF)
 // Vendor extensions:
-HANDLE_DW_LANG(0x8001, Mips_Assembler, None, 0, MIPS)
+HANDLE_DW_LANG(0x8001, Mips_Assembler, std::nullopt, 0, MIPS)
 HANDLE_DW_LANG(0x8e57, GOOGLE_RenderScript, 0, 0, GOOGLE)
 HANDLE_DW_LANG(0xb000, BORLAND_Delphi, 0, 0, BORLAND)
 

llvm/include/llvm/Bitstream/BitstreamWriter.h

@@ -502,7 +502,8 @@ public:
   /// the first entry.
   template <typename Container>
   void EmitRecordWithAbbrev(unsigned Abbrev, const Container &Vals) {
-    EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), StringRef(), None);
+    EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), StringRef(),
+                             std::nullopt);
   }
 
   /// EmitRecordWithBlob - Emit the specified record to the stream, using an
@@ -513,13 +514,13 @@ public:
   template <typename Container>
   void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals,
                           StringRef Blob) {
-    EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), Blob, None);
+    EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), Blob, std::nullopt);
   }
   template <typename Container>
   void EmitRecordWithBlob(unsigned Abbrev, const Container &Vals,
                           const char *BlobData, unsigned BlobLen) {
     return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
-                                    StringRef(BlobData, BlobLen), None);
+                                    StringRef(BlobData, BlobLen), std::nullopt);
   }
 
   /// EmitRecordWithArray - Just like EmitRecordWithBlob, works with records
@@ -527,13 +528,14 @@ public:
   template <typename Container>
   void EmitRecordWithArray(unsigned Abbrev, const Container &Vals,
                            StringRef Array) {
-    EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), Array, None);
+    EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals), Array, std::nullopt);
   }
   template <typename Container>
   void EmitRecordWithArray(unsigned Abbrev, const Container &Vals,
                            const char *ArrayData, unsigned ArrayLen) {
     return EmitRecordWithAbbrevImpl(Abbrev, makeArrayRef(Vals),
-                                    StringRef(ArrayData, ArrayLen), None);
+                                    StringRef(ArrayData, ArrayLen),
+                                    std::nullopt);
   }
 
   //===--------------------------------------------------------------------===//

llvm/include/llvm/DWP/DWP.h

@@ -44,7 +44,7 @@ struct InfoSectionUnitHeader {
 
   // dwo_id field. This resides in the header only if Version >= 5.
   // In earlier versions, it is read from DW_AT_GNU_dwo_id.
-  Optional<uint64_t> Signature = None;
+  Optional<uint64_t> Signature = std::nullopt;
 
   // Derived from the length of Length field.
   dwarf::DwarfFormat Format = dwarf::DwarfFormat::DWARF32;

llvm/include/llvm/ExecutionEngine/Orc/COFFPlatform.h

@@ -44,7 +44,7 @@ public:
          JITDylib &PlatformJD, const char *OrcRuntimePath,
          LoadDynamicLibrary LoadDynLibrary, bool StaticVCRuntime = false,
          const char *VCRuntimePath = nullptr,
-         Optional<SymbolAliasMap> RuntimeAliases = None);
+         Optional<SymbolAliasMap> RuntimeAliases = std::nullopt);
 
   ExecutionSession &getExecutionSession() const { return ES; }
   ObjectLinkingLayer &getObjectLinkingLayer() const { return ObjLinkingLayer; }

llvm/include/llvm/ExecutionEngine/Orc/ELFNixPlatform.h

@@ -95,7 +95,7 @@ public:
   static Expected<std::unique_ptr<ELFNixPlatform>>
   Create(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer,
          JITDylib &PlatformJD, const char *OrcRuntimePath,
-         Optional<SymbolAliasMap> RuntimeAliases = None);
+         Optional<SymbolAliasMap> RuntimeAliases = std::nullopt);
 
   ExecutionSession &getExecutionSession() const { return ES; }
   ObjectLinkingLayer &getObjectLinkingLayer() const { return ObjLinkingLayer; }

llvm/include/llvm/ExecutionEngine/Orc/EPCDebugObjectRegistrar.h

@@ -58,7 +58,7 @@ private:
 /// loaded to find the registration functions.
 Expected<std::unique_ptr<EPCDebugObjectRegistrar>> createJITLoaderGDBRegistrar(
     ExecutionSession &ES,
-    Optional<ExecutorAddr> RegistrationFunctionDylib = None);
+    Optional<ExecutorAddr> RegistrationFunctionDylib = std::nullopt);
 
 } // end namespace orc
 } // end namespace llvm

llvm/include/llvm/ExecutionEngine/Orc/EPCEHFrameRegistrar.h

@@ -34,7 +34,7 @@ public:
   /// will be loaded to find the registration functions.
   static Expected<std::unique_ptr<EPCEHFrameRegistrar>>
   Create(ExecutionSession &ES,
-         Optional<ExecutorAddr> RegistrationFunctionsDylib = None);
+         Optional<ExecutorAddr> RegistrationFunctionsDylib = std::nullopt);
 
   /// Create a EPCEHFrameRegistrar with the given ExecutorProcessControl
   /// object and registration/deregistration function addresses.

llvm/include/llvm/ExecutionEngine/Orc/MachOPlatform.h

@@ -80,7 +80,7 @@ public:
   static Expected<std::unique_ptr<MachOPlatform>>
   Create(ExecutionSession &ES, ObjectLinkingLayer &ObjLinkingLayer,
          JITDylib &PlatformJD, const char *OrcRuntimePath,
-         Optional<SymbolAliasMap> RuntimeAliases = None);
+         Optional<SymbolAliasMap> RuntimeAliases = std::nullopt);
 
   ExecutionSession &getExecutionSession() const { return ES; }
   ObjectLinkingLayer &getObjectLinkingLayer() const { return ObjLinkingLayer; }

llvm/include/llvm/ExecutionEngine/Orc/Speculation.h

@@ -50,7 +50,7 @@ private:
     if (Position != Maps.end())
       return Position->getSecond();
     else
-      return None;
+      return std::nullopt;
   }
 
   std::mutex ConcurrentAccess;

llvm/include/llvm/ExecutionEngine/Orc/TargetProcess/TargetExecutionUtils.h

@@ -30,7 +30,7 @@ namespace orc {
 /// many main functions will expect a name argument at least, and will fail
 /// if none is provided.
 int runAsMain(int (*Main)(int, char *[]), ArrayRef<std::string> Args,
-              Optional<StringRef> ProgramName = None);
+              Optional<StringRef> ProgramName = std::nullopt);
 
 int runAsVoidFunction(int (*Func)(void));
 int runAsIntFunction(int (*Func)(int), int Arg);

llvm/include/llvm/Frontend/OpenMP/OMPKinds.def

@@ -924,7 +924,7 @@ __OMP_RTL_ATTRS(__kmpc_doacross_fini, BarrierAttrs, AttributeSet(),
 __OMP_RTL_ATTRS(__kmpc_alloc_shared, AttributeSet(
   EnumAttr(NoUnwind),
   EnumAttr(NoSync),
-  AllocSizeAttr(0, None)), ReturnPtrAttrs, ParamAttrs())
+  AllocSizeAttr(0, std::nullopt)), ReturnPtrAttrs, ParamAttrs())
 __OMP_RTL_ATTRS(__kmpc_free_shared, DeviceAllocAttrs, AttributeSet(),
                 ParamAttrs(AttributeSet(EnumAttr(NoCapture), EnumAttr(AllocatedPointer))))
 

llvm/include/llvm/FuzzMutate/OpDescriptor.h

@@ -105,7 +105,7 @@ static inline SourcePred anyType() {
   auto Pred = [](ArrayRef<Value *>, const Value *V) {
     return !V->getType()->isVoidTy();
   };
-  auto Make = None;
+  auto Make = std::nullopt;
   return {Pred, Make};
 }
 
@@ -113,7 +113,7 @@ static inline SourcePred anyIntType() {
   auto Pred = [](ArrayRef<Value *>, const Value *V) {
     return V->getType()->isIntegerTy();
   };
-  auto Make = None;
+  auto Make = std::nullopt;
   return {Pred, Make};
 }
 
@@ -121,7 +121,7 @@ static inline SourcePred anyFloatType() {
   auto Pred = [](ArrayRef<Value *>, const Value *V) {
     return V->getType()->isFloatingPointTy();
   };
-  auto Make = None;
+  auto Make = std::nullopt;
   return {Pred, Make};
 }
 
@@ -175,7 +175,7 @@ static inline SourcePred anyAggregateType() {
   };
   // TODO: For now we only find aggregates in BaseTypes. It might be better to
   // manufacture them out of the base types in some cases.
-  auto Find = None;
+  auto Find = std::nullopt;
   return {Pred, Find};
 }
 
@@ -186,7 +186,7 @@ static inline SourcePred anyVectorType() {
   // TODO: For now we only find vectors in BaseTypes. It might be better to
   // manufacture vectors out of the base types, but it's tricky to be sure
   // that's actually a reasonable type.
-  auto Make = None;
+  auto Make = std::nullopt;
   return {Pred, Make};
 }
 

llvm/include/llvm/IRReader/IRReader.h

@@ -56,7 +56,9 @@ getLazyIRFileModule(StringRef Filename, SMDiagnostic &Err, LLVMContext &Context,
 /// \param DataLayoutCallback Override datalayout in the llvm assembly.
 std::unique_ptr<Module> parseIR(
     MemoryBufferRef Buffer, SMDiagnostic &Err, LLVMContext &Context,
-    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) { return None; });
+    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) {
+      return std::nullopt;
+    });
 
 /// If the given file holds a bitcode image, return a Module for it.
 /// Otherwise, attempt to parse it as LLVM Assembly and return a Module
@@ -64,7 +66,9 @@ std::unique_ptr<Module> parseIR(
 /// \param DataLayoutCallback Override datalayout in the llvm assembly.
 std::unique_ptr<Module> parseIRFile(
     StringRef Filename, SMDiagnostic &Err, LLVMContext &Context,
-    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) { return None; });
+    DataLayoutCallbackTy DataLayoutCallback = [](StringRef) {
+      return std::nullopt;
+    });
 }
 
 #endif

llvm/include/llvm/LTO/Config.h

@@ -52,7 +52,7 @@ struct Config {
   /// For adding passes that run right before codegen.
   std::function<void(legacy::PassManager &)> PreCodeGenPassesHook;
   Optional<Reloc::Model> RelocModel = Reloc::PIC_;
-  Optional<CodeModel::Model> CodeModel = None;
+  Optional<CodeModel::Model> CodeModel = std::nullopt;
   CodeGenOpt::Level CGOptLevel = CodeGenOpt::Default;
   CodeGenFileType CGFileType = CGFT_ObjectFile;
   unsigned OptLevel = 2;

llvm/include/llvm/MC/MCContext.h

@@ -672,11 +672,13 @@ public:
   bool hasXCOFFSection(StringRef Section,
                        XCOFF::CsectProperties CsectProp) const;
 
-  MCSectionXCOFF *getXCOFFSection(
-      StringRef Section, SectionKind K,
-      Optional<XCOFF::CsectProperties> CsectProp = None,
-      bool MultiSymbolsAllowed = false, const char *BeginSymName = nullptr,
-      Optional<XCOFF::DwarfSectionSubtypeFlags> DwarfSubtypeFlags = None);
+  MCSectionXCOFF *
+  getXCOFFSection(StringRef Section, SectionKind K,
+                  Optional<XCOFF::CsectProperties> CsectProp = std::nullopt,
+                  bool MultiSymbolsAllowed = false,
+                  const char *BeginSymName = nullptr,
+                  Optional<XCOFF::DwarfSectionSubtypeFlags> DwarfSubtypeFlags =
+                      std::nullopt);
 
   // Create and save a copy of STI and return a reference to the copy.
   MCSubtargetInfo &getSubtargetCopy(const MCSubtargetInfo &STI);

llvm/include/llvm/MC/MCParser/MCAsmParser.h

@@ -210,25 +210,28 @@ public:
       const MCInstPrinter *IP, MCAsmParserSemaCallback &SI) = 0;
 
   /// Emit a note at the location \p L, with the message \p Msg.
-  virtual void Note(SMLoc L, const Twine &Msg, SMRange Range = None) = 0;
+  virtual void Note(SMLoc L, const Twine &Msg,
+                    SMRange Range = std::nullopt) = 0;
 
   /// Emit a warning at the location \p L, with the message \p Msg.
   ///
   /// \return The return value is true, if warnings are fatal.
-  virtual bool Warning(SMLoc L, const Twine &Msg, SMRange Range = None) = 0;
+  virtual bool Warning(SMLoc L, const Twine &Msg,
+                       SMRange Range = std::nullopt) = 0;
 
   /// Return an error at the location \p L, with the message \p Msg. This
   /// may be modified before being emitted.
   ///
   /// \return The return value is always true, as an idiomatic convenience to
   /// clients.
-  bool Error(SMLoc L, const Twine &Msg, SMRange Range = None);
+  bool Error(SMLoc L, const Twine &Msg, SMRange Range = std::nullopt);
 
   /// Emit an error at the location \p L, with the message \p Msg.
   ///
   /// \return The return value is always true, as an idiomatic convenience to
   /// clients.
-  virtual bool printError(SMLoc L, const Twine &Msg, SMRange Range = None) = 0;
+  virtual bool printError(SMLoc L, const Twine &Msg,
+                          SMRange Range = std::nullopt) = 0;
 
   bool hasPendingError() { return !PendingErrors.empty(); }
 
@@ -253,7 +256,7 @@ public:
   const AsmToken &getTok() const;
 
   /// Report an error at the current lexer location.
-  bool TokError(const Twine &Msg, SMRange Range = None);
+  bool TokError(const Twine &Msg, SMRange Range = std::nullopt);
 
   bool parseTokenLoc(SMLoc &Loc);
   bool parseToken(AsmToken::TokenKind T, const Twine &Msg = "unexpected token");

llvm/include/llvm/MC/MCSectionXCOFF.h

@@ -46,7 +46,7 @@ class MCSectionXCOFF final : public MCSection {
                  bool MultiSymbolsAllowed)
       : MCSection(SV_XCOFF, Name, K, Begin),
         CsectProp(XCOFF::CsectProperties(SMC, ST)), QualName(QualName),
-        SymbolTableName(SymbolTableName), DwarfSubtypeFlags(None),
+        SymbolTableName(SymbolTableName), DwarfSubtypeFlags(std::nullopt),
         MultiSymbolsAllowed(MultiSymbolsAllowed) {
     assert(
         (ST == XCOFF::XTY_SD || ST == XCOFF::XTY_CM || ST == XCOFF::XTY_ER) &&

llvm/include/llvm/MC/MCStreamer.h

@@ -905,11 +905,10 @@ public:
 
   /// Associate a filename with a specified logical file number.  This
   /// implements the DWARF2 '.file 4 "foo.c"' assembler directive.
-  unsigned emitDwarfFileDirective(unsigned FileNo, StringRef Directory,
-                                  StringRef Filename,
-                                  Optional<MD5::MD5Result> Checksum = None,
-                                  Optional<StringRef> Source = None,
-                                  unsigned CUID = 0) {
+  unsigned emitDwarfFileDirective(
+      unsigned FileNo, StringRef Directory, StringRef Filename,
+      Optional<MD5::MD5Result> Checksum = std::nullopt,
+      Optional<StringRef> Source = std::nullopt, unsigned CUID = 0) {
     return cantFail(
         tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum,
                                   Source, CUID));
@@ -922,8 +921,8 @@ public:
   /// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive.
   virtual Expected<unsigned> tryEmitDwarfFileDirective(
       unsigned FileNo, StringRef Directory, StringRef Filename,
-      Optional<MD5::MD5Result> Checksum = None, Optional<StringRef> Source = None,
-      unsigned CUID = 0);
+      Optional<MD5::MD5Result> Checksum = std::nullopt,
+      Optional<StringRef> Source = std::nullopt, unsigned CUID = 0);
 
   /// Specify the "root" file of the compilation, using the ".file 0" extension.
   virtual void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
@@ -1089,7 +1088,7 @@ public:
   virtual Optional<std::pair<bool, std::string>>
   emitRelocDirective(const MCExpr &Offset, StringRef Name, const MCExpr *Expr,
                      SMLoc Loc, const MCSubtargetInfo &STI) {
-    return None;
+    return std::nullopt;
   }
 
   virtual void emitAddrsig() {}

llvm/include/llvm/MC/TargetRegistry.h

@@ -478,11 +478,10 @@ public:
   /// feature set; it should always be provided. Generally this should be
   /// either the target triple from the module, or the target triple of the
   /// host if that does not exist.
-  TargetMachine *createTargetMachine(StringRef TT, StringRef CPU,
-                                     StringRef Features,
-                                     const TargetOptions &Options,
-                                     Optional<Reloc::Model> RM,
-                                     Optional<CodeModel::Model> CM = None,
+  TargetMachine *
+  createTargetMachine(StringRef TT, StringRef CPU, StringRef Features,
+                      const TargetOptions &Options, Optional<Reloc::Model> RM,
+                      Optional<CodeModel::Model> CM = std::nullopt,
                       CodeGenOpt::Level OL = CodeGenOpt::Default,
                       bool JIT = false) const {
     if (!TargetMachineCtorFn)

llvm/include/llvm/ObjCopy/CommonConfig.h

@@ -118,7 +118,7 @@ public:
   Optional<StringRef> getName() const {
     if (!R && !G)
       return Name;
-    return None;
+    return std::nullopt;
   }
   bool operator==(StringRef S) const {
     return R ? R->match(S) : G ? G->match(S) : Name == S;

llvm/include/llvm/Object/ELF.h

@@ -120,7 +120,7 @@ template <class T> struct DataRegion {
   }
 
   const T *First;
-  Optional<uint64_t> Size = None;
+  Optional<uint64_t> Size = std::nullopt;
   const uint8_t *BufEnd = nullptr;
 };
 

llvm/include/llvm/Object/ELFObjectFile.h

@@ -108,7 +108,7 @@ public:
   // `TextSectionIndex` is specified, only returns the BB address maps
   // corresponding to the section with that index.
   Expected<std::vector<BBAddrMap>>
-  readBBAddrMap(Optional<unsigned> TextSectionIndex = None) const;
+  readBBAddrMap(Optional<unsigned> TextSectionIndex = std::nullopt) const;
 };
 
 class ELFSectionRef : public SectionRef {

llvm/include/llvm/Object/ObjectFile.h

@@ -337,7 +337,7 @@ public:
   virtual StringRef getFileFormatName() const = 0;
   virtual Triple::ArchType getArch() const = 0;
   virtual SubtargetFeatures getFeatures() const = 0;
-  virtual Optional<StringRef> tryGetCPUName() const { return None; };
+  virtual Optional<StringRef> tryGetCPUName() const { return std::nullopt; };
   virtual void setARMSubArch(Triple &TheTriple) const { }
   virtual Expected<uint64_t> getStartAddress() const {
     return errorCodeToError(object_error::parse_failed);

llvm/include/llvm/Passes/PassBuilder.h

@@ -116,7 +116,7 @@ public:
 
   explicit PassBuilder(TargetMachine *TM = nullptr,
                        PipelineTuningOptions PTO = PipelineTuningOptions(),
-                       Optional<PGOOptions> PGOOpt = None,
+                       Optional<PGOOptions> PGOOpt = std::nullopt,
                        PassInstrumentationCallbacks *PIC = nullptr);
 
   /// Cross register the analysis managers through their proxies.

llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h

@@ -323,7 +323,7 @@ class CounterMappingContext {
 
 public:
   CounterMappingContext(ArrayRef<CounterExpression> Expressions,
-                        ArrayRef<uint64_t> CounterValues = None)
+                        ArrayRef<uint64_t> CounterValues = std::nullopt)
       : Expressions(Expressions), CounterValues(CounterValues) {}
 
   void setCounts(ArrayRef<uint64_t> Counts) { CounterValues = Counts; }
@@ -605,7 +605,8 @@ public:
   /// Ignores non-instrumented object files unless all are not instrumented.
   static Expected<std::unique_ptr<CoverageMapping>>
   load(ArrayRef<StringRef> ObjectFilenames, StringRef ProfileFilename,
-       ArrayRef<StringRef> Arches = None, StringRef CompilationDir = "");
+       ArrayRef<StringRef> Arches = std::nullopt,
+       StringRef CompilationDir = "");
 
   /// The number of functions that couldn't have their profiles mapped.
   ///

llvm/include/llvm/ProfileData/InstrProf.h

@@ -868,7 +868,7 @@ private:
   ArrayRef<InstrProfValueSiteRecord>
   getValueSitesForKind(uint32_t ValueKind) const {
     if (!ValueData)
-      return None;
+      return std::nullopt;
     switch (ValueKind) {
     case IPVK_IndirectCallTarget:
       return ValueData->IndirectCallSites;

llvm/include/llvm/Remarks/BitstreamRemarkSerializer.h

@@ -106,8 +106,8 @@ struct BitstreamRemarkSerializerHelper {
   /// Emit the metadata for the remarks.
   void emitMetaBlock(uint64_t ContainerVersion,
                      Optional<uint64_t> RemarkVersion,
-                     Optional<const StringTable *> StrTab = None,
-                     Optional<StringRef> Filename = None);
+                     Optional<const StringTable *> StrTab = std::nullopt,
+                     Optional<StringRef> Filename = std::nullopt);
 
   /// Emit a remark block. The string table is required.
   void emitRemarkBlock(const Remark &Remark, StringTable &StrTab);
@@ -148,7 +148,7 @@ struct BitstreamRemarkSerializer : public RemarkSerializer {
   /// metadata serializer will change.
   std::unique_ptr<MetaSerializer>
   metaSerializer(raw_ostream &OS,
-                 Optional<StringRef> ExternalFilename = None) override;
+                 Optional<StringRef> ExternalFilename = std::nullopt) override;
 
   static bool classof(const RemarkSerializer *S) {
     return S->SerializerFormat == Format::Bitstream;
@@ -172,10 +172,10 @@ struct BitstreamMetaSerializer : public MetaSerializer {
   /// Create a new meta serializer based on \p ContainerType.
   BitstreamMetaSerializer(raw_ostream &OS,
                           BitstreamRemarkContainerType ContainerType,
-                          Optional<const StringTable *> StrTab = None,
-                          Optional<StringRef> ExternalFilename = None)
-      : MetaSerializer(OS), TmpHelper(None), Helper(nullptr), StrTab(StrTab),
-        ExternalFilename(ExternalFilename) {
+                          Optional<const StringTable *> StrTab = std::nullopt,
+                          Optional<StringRef> ExternalFilename = std::nullopt)
+      : MetaSerializer(OS), TmpHelper(std::nullopt), Helper(nullptr),
+        StrTab(StrTab), ExternalFilename(ExternalFilename) {
     TmpHelper.emplace(ContainerType);
     Helper = &*TmpHelper;
   }
@@ -183,10 +183,10 @@ struct BitstreamMetaSerializer : public MetaSerializer {
   /// Create a new meta serializer based on a previously built \p Helper.
   BitstreamMetaSerializer(raw_ostream &OS,
                           BitstreamRemarkSerializerHelper &Helper,
-                          Optional<const StringTable *> StrTab = None,
-                          Optional<StringRef> ExternalFilename = None)
-      : MetaSerializer(OS), TmpHelper(None), Helper(&Helper), StrTab(StrTab),
-        ExternalFilename(ExternalFilename) {}
+                          Optional<const StringTable *> StrTab = std::nullopt,
+                          Optional<StringRef> ExternalFilename = std::nullopt)
+      : MetaSerializer(OS), TmpHelper(std::nullopt), Helper(&Helper),
+        StrTab(StrTab), ExternalFilename(ExternalFilename) {}
 
   void emit() override;
 };

llvm/include/llvm/Remarks/HotnessThresholdParser.h

@@ -30,7 +30,7 @@ namespace remarks {
 // be filled later during PSI.
 inline Expected<Optional<uint64_t>> parseHotnessThresholdOption(StringRef Arg) {
   if (Arg == "auto")
-    return None;
+    return std::nullopt;
 
   int64_t Val;
   if (Arg.getAsInteger(10, Val))

llvm/include/llvm/Remarks/RemarkLinker.h

@@ -65,12 +65,12 @@ public:
   /// \p Buffer.
   /// \p Buffer can be either a standalone remark container or just
   /// metadata. This takes care of uniquing and merging the remarks.
-  Error link(StringRef Buffer, Optional<Format> RemarkFormat = None);
+  Error link(StringRef Buffer, Optional<Format> RemarkFormat = std::nullopt);
 
   /// Link the remarks found in \p Obj by looking for the right section and
   /// calling the method above.
   Error link(const object::ObjectFile &Obj,
-             Optional<Format> RemarkFormat = None);
+             Optional<Format> RemarkFormat = std::nullopt);
 
   /// Serialize the linked remarks to the stream \p OS, using the format \p
   /// RemarkFormat.

llvm/include/llvm/Remarks/RemarkParser.h

@@ -82,10 +82,10 @@ Expected<std::unique_ptr<RemarkParser>>
 createRemarkParser(Format ParserFormat, StringRef Buf,
                    ParsedStringTable StrTab);
 
-Expected<std::unique_ptr<RemarkParser>>
-createRemarkParserFromMeta(Format ParserFormat, StringRef Buf,
-                           Optional<ParsedStringTable> StrTab = None,
-                           Optional<StringRef> ExternalFilePrependPath = None);
+Expected<std::unique_ptr<RemarkParser>> createRemarkParserFromMeta(
+    Format ParserFormat, StringRef Buf,
+    Optional<ParsedStringTable> StrTab = std::nullopt,
+    Optional<StringRef> ExternalFilePrependPath = std::nullopt);
 
 } // end namespace remarks
 } // end namespace llvm

llvm/include/llvm/Remarks/RemarkSerializer.h

@@ -60,7 +60,7 @@ struct RemarkSerializer {
   /// Return the corresponding metadata serializer.
   virtual std::unique_ptr<MetaSerializer>
   metaSerializer(raw_ostream &OS,
-                 Optional<StringRef> ExternalFilename = None) = 0;
+                 Optional<StringRef> ExternalFilename = std::nullopt) = 0;
 };
 
 /// This is the base class for a remark metadata serializer.

llvm/include/llvm/Remarks/RemarkStreamer.h

@@ -51,11 +51,11 @@ class RemarkStreamer final {
 
 public:
   RemarkStreamer(std::unique_ptr<remarks::RemarkSerializer> RemarkSerializer,
-                 Optional<StringRef> Filename = None);
+                 Optional<StringRef> Filename = std::nullopt);
 
   /// Return the filename that the remark diagnostics are emitted to.
   Optional<StringRef> getFilename() const {
-    return Filename ? Optional<StringRef>(*Filename) : None;
+    return Filename ? Optional<StringRef>(*Filename) : std::nullopt;
   }
   /// Return stream that the remark diagnostics are emitted to.
   raw_ostream &getStream() { return RemarkSerializer->OS; }

llvm/include/llvm/Remarks/YAMLRemarkSerializer.h

@@ -35,12 +35,12 @@ struct YAMLRemarkSerializer : public RemarkSerializer {
   yaml::Output YAMLOutput;
 
   YAMLRemarkSerializer(raw_ostream &OS, SerializerMode Mode,
-                       Optional<StringTable> StrTab = None);
+                       Optional<StringTable> StrTab = std::nullopt);
 
   void emit(const Remark &Remark) override;
   std::unique_ptr<MetaSerializer>
   metaSerializer(raw_ostream &OS,
-                 Optional<StringRef> ExternalFilename = None) override;
+                 Optional<StringRef> ExternalFilename = std::nullopt) override;
 
   static bool classof(const RemarkSerializer *S) {
     return S->SerializerFormat == Format::YAML;
@@ -49,7 +49,7 @@ struct YAMLRemarkSerializer : public RemarkSerializer {
 protected:
   YAMLRemarkSerializer(Format SerializerFormat, raw_ostream &OS,
                        SerializerMode Mode,
-                       Optional<StringTable> StrTab = None);
+                       Optional<StringTable> StrTab = std::nullopt);
 };
 
 struct YAMLMetaSerializer : public MetaSerializer {
@@ -83,7 +83,7 @@ struct YAMLStrTabRemarkSerializer : public YAMLRemarkSerializer {
 
   std::unique_ptr<MetaSerializer>
   metaSerializer(raw_ostream &OS,
-                 Optional<StringRef> ExternalFilename = None) override;
+                 Optional<StringRef> ExternalFilename = std::nullopt) override;
 
   static bool classof(const RemarkSerializer *S) {
     return S->SerializerFormat == Format::YAMLStrTab;

llvm/include/llvm/Target/CodeGenCWrappers.h

@@ -29,7 +29,7 @@ inline Optional<CodeModel::Model> unwrap(LLVMCodeModel Model, bool &JIT) {
     JIT = true;
     [[fallthrough]];
   case LLVMCodeModelDefault:
-    return None;
+    return std::nullopt;
   case LLVMCodeModelTiny:
     return CodeModel::Tiny;
   case LLVMCodeModelSmall:

llvm/include/llvm/Target/TargetMachine.h

@@ -110,7 +110,7 @@ protected: // Can only create subclasses.
   unsigned O0WantsFastISel : 1;
 
   // PGO related tunables.
-  Optional<PGOOptions> PGOOption = None;
+  Optional<PGOOptions> PGOOption = std::nullopt;
 
 public:
   const TargetOptions DefaultOptions;

llvm/lib/AsmParser/LLParser.cpp

@@ -783,7 +783,7 @@ bool LLParser::parseMDNodeID(MDNode *&Result) {
 
   // Otherwise, create MDNode forward reference.
   auto &FwdRef = ForwardRefMDNodes[MID];
-  FwdRef = std::make_pair(MDTuple::getTemporary(Context, None), IDLoc);
+  FwdRef = std::make_pair(MDTuple::getTemporary(Context, std::nullopt), IDLoc);
 
   Result = FwdRef.first.get();
   NumberedMetadata[MID].reset(Result);
@@ -2132,7 +2132,7 @@ bool LLParser::parseOptionalFunctionMetadata(Function &F) {
 ///   ::= /* empty */
 ///   ::= 'align' 4
 bool LLParser::parseOptionalAlignment(MaybeAlign &Alignment, bool AllowParens) {
-  Alignment = None;
+  Alignment = std::nullopt;
   if (!EatIfPresent(lltok::kw_align))
     return false;
   LocTy AlignLoc = Lex.getLoc();
@@ -2244,7 +2244,7 @@ static Optional<MemoryEffects::Location> keywordToLoc(lltok::Kind Tok) {
   case lltok::kw_inaccessiblemem:
     return MemoryEffects::InaccessibleMem;
   default:
-    return None;
+    return std::nullopt;
   }
 }
 
@@ -2259,7 +2259,7 @@ static Optional<ModRefInfo> keywordToModRef(lltok::Kind Tok) {
   case lltok::kw_readwrite:
     return ModRefInfo::ModRef;
   default:
-    return None;
+    return std::nullopt;
   }
 }
 
@@ -2274,7 +2274,7 @@ Optional<MemoryEffects> LLParser::parseMemoryAttr() {
   Lex.Lex();
   if (!EatIfPresent(lltok::lparen)) {
     tokError("expected '('");
-    return None;
+    return std::nullopt;
   }
 
   bool SeenLoc = false;
@@ -2284,7 +2284,7 @@ Optional<MemoryEffects> LLParser::parseMemoryAttr() {
       Lex.Lex();
       if (!EatIfPresent(lltok::colon)) {
         tokError("expected ':' after location");
-        return None;
+        return std::nullopt;
       }
     }
 
@@ -2295,7 +2295,7 @@ Optional<MemoryEffects> LLParser::parseMemoryAttr() {
                  "or access kind (none, read, write, readwrite)");
       else
         tokError("expected access kind (none, read, write, readwrite)");
-      return None;
+      return std::nullopt;
     }
 
     Lex.Lex();
@@ -2305,7 +2305,7 @@ Optional<MemoryEffects> LLParser::parseMemoryAttr() {
     } else {
       if (SeenLoc) {
         tokError("default access kind must be specified first");
-        return None;
+        return std::nullopt;
       }
       ME = MemoryEffects(*MR);
     }
@@ -2315,7 +2315,7 @@ Optional<MemoryEffects> LLParser::parseMemoryAttr() {
   } while (EatIfPresent(lltok::comma));
 
   tokError("unterminated memory attribute");
-  return None;
+  return std::nullopt;
 }
 
 /// parseOptionalCommaAlign
@@ -2392,7 +2392,7 @@ bool LLParser::parseAllocSizeArguments(unsigned &BaseSizeArg,
                    "'allocsize' indices can't refer to the same parameter");
     HowManyArg = HowMany;
   } else
-    HowManyArg = None;
+    HowManyArg = std::nullopt;
 
   auto EndParen = Lex.getLoc();
   if (!EatIfPresent(lltok::rparen))

llvm/lib/AsmParser/Parser.cpp

@@ -93,7 +93,7 @@ ParsedModuleAndIndex llvm::parseAssemblyWithIndex(MemoryBufferRef F,
                                                   SlotMapping *Slots) {
   return ::parseAssemblyWithIndex(F, Err, Context, Slots,
                                   /*UpgradeDebugInfo*/ true,
-                                  [](StringRef) { return None; });
+                                  [](StringRef) { return std::nullopt; });
 }
 
 static ParsedModuleAndIndex
@@ -150,7 +150,7 @@ static bool parseSummaryIndexAssemblyInto(MemoryBufferRef F,
   // index, but we need to initialize it.
   LLVMContext unusedContext;
   return LLParser(F.getBuffer(), SM, Err, nullptr, &Index, unusedContext)
-      .Run(true, [](StringRef) { return None; });
+      .Run(true, [](StringRef) { return std::nullopt; });
 }
 
 std::unique_ptr<ModuleSummaryIndex>

llvm/lib/BinaryFormat/Dwarf.cpp

@@ -368,7 +368,7 @@ unsigned llvm::dwarf::LanguageVendor(dwarf::SourceLanguage Lang) {
 Optional<unsigned> llvm::dwarf::LanguageLowerBound(dwarf::SourceLanguage Lang) {
   switch (Lang) {
   default:
-    return None;
+    return std::nullopt;
 #define HANDLE_DW_LANG(ID, NAME, LOWER_BOUND, VERSION, VENDOR)                 \
   case DW_LANG_##NAME:                                                         \
     return LOWER_BOUND;
@@ -697,7 +697,7 @@ Optional<uint8_t> llvm::dwarf::getFixedFormByteSize(dwarf::Form Form,
   case DW_FORM_addr:
     if (Params)
       return Params.AddrSize;
-    return None;
+    return std::nullopt;
 
   case DW_FORM_block:          // ULEB128 length L followed by L bytes.
   case DW_FORM_block1:         // 1 byte length L followed by L bytes.
@@ -715,12 +715,12 @@ Optional<uint8_t> llvm::dwarf::getFixedFormByteSize(dwarf::Form Form,
   case DW_FORM_rnglistx:       // ULEB128.
   case DW_FORM_GNU_addr_index: // ULEB128.
   case DW_FORM_GNU_str_index:  // ULEB128.
-    return None;
+    return std::nullopt;
 
   case DW_FORM_ref_addr:
     if (Params)
       return Params.getRefAddrByteSize();
-    return None;
+    return std::nullopt;
 
   case DW_FORM_flag:
   case DW_FORM_data1:
@@ -753,7 +753,7 @@ Optional<uint8_t> llvm::dwarf::getFixedFormByteSize(dwarf::Form Form,
   case DW_FORM_strp_sup:
     if (Params)
       return Params.getDwarfOffsetByteSize();
-    return None;
+    return std::nullopt;
 
   case DW_FORM_data8:
   case DW_FORM_ref8:
@@ -775,7 +775,7 @@ Optional<uint8_t> llvm::dwarf::getFixedFormByteSize(dwarf::Form Form,
   default:
     break;
   }
-  return None;
+  return std::nullopt;
 }
 
 bool llvm::dwarf::isValidFormForVersion(Form F, unsigned Version,

llvm/lib/Bitstream/Reader/BitstreamReader.cpp

@@ -438,7 +438,7 @@ BitstreamCursor::ReadBlockInfoBlock(bool ReadBlockInfoNames) {
     switch (Entry.Kind) {
     case llvm::BitstreamEntry::SubBlock: // Handled for us already.
     case llvm::BitstreamEntry::Error:
-      return None;
+      return std::nullopt;
     case llvm::BitstreamEntry::EndBlock:
       return std::move(NewBlockInfo);
     case llvm::BitstreamEntry::Record:
@@ -448,7 +448,8 @@ BitstreamCursor::ReadBlockInfoBlock(bool ReadBlockInfoNames) {
 
     // Read abbrev records, associate them with CurBID.
     if (Entry.ID == bitc::DEFINE_ABBREV) {
-      if (!CurBlockInfo) return None;
+      if (!CurBlockInfo)
+        return std::nullopt;
       if (Error Err = ReadAbbrevRecord())
         return std::move(Err);
 
@@ -469,19 +470,20 @@ BitstreamCursor::ReadBlockInfoBlock(bool ReadBlockInfoNames) {
       break; // Default behavior, ignore unknown content.
     case bitc::BLOCKINFO_CODE_SETBID:
       if (Record.size() < 1)
-        return None;
+        return std::nullopt;
       CurBlockInfo = &NewBlockInfo.getOrCreateBlockInfo((unsigned)Record[0]);
       break;
     case bitc::BLOCKINFO_CODE_BLOCKNAME: {
       if (!CurBlockInfo)
-        return None;
+        return std::nullopt;
       if (!ReadBlockInfoNames)
         break; // Ignore name.
       CurBlockInfo->Name = std::string(Record.begin(), Record.end());
       break;
     }
       case bitc::BLOCKINFO_CODE_SETRECORDNAME: {
-        if (!CurBlockInfo) return None;
+      if (!CurBlockInfo)
+        return std::nullopt;
       if (!ReadBlockInfoNames)
         break; // Ignore name.
       CurBlockInfo->RecordNames.emplace_back(

llvm/lib/DWARFLinker/DWARFStreamer.cpp

@@ -96,7 +96,7 @@ bool DwarfStreamer::init(Triple TheTriple,
 
   // Finally create the AsmPrinter we'll use to emit the DIEs.
   TM.reset(TheTarget->createTargetMachine(TripleName, "", "", TargetOptions(),
-                                          None));
+                                          std::nullopt));
   if (!TM)
     return error("no target machine for target " + TripleName, Context), false;
 

llvm/lib/Debuginfod/BuildIDFetcher.cpp

@@ -27,5 +27,5 @@ DebuginfodFetcher::fetch(ArrayRef<uint8_t> BuildID) const {
   if (PathOrErr)
     return *PathOrErr;
   consumeError(PathOrErr.takeError());
-  return None;
+  return std::nullopt;
 }

llvm/lib/Debuginfod/Debuginfod.cpp

@@ -434,7 +434,7 @@ DebuginfodCollection::getBinaryPath(BuildIDRef ID) {
     std::string Path = Loc->getValue();
     return Path;
   }
-  return None;
+  return std::nullopt;
 }
 
 Expected<Optional<std::string>>
@@ -446,7 +446,7 @@ DebuginfodCollection::getDebugBinaryPath(BuildIDRef ID) {
     std::string Path = Loc->getValue();
     return Path;
   }
-  return None;
+  return std::nullopt;
 }
 
 Expected<std::string> DebuginfodCollection::findBinaryPath(BuildIDRef ID) {

llvm/lib/ExecutionEngine/ExecutionEngine.cpp

@@ -395,7 +395,7 @@ void ExecutionEngine::runStaticConstructorsDestructors(Module &module,
 
     // Execute the ctor/dtor function!
     if (Function *F = dyn_cast<Function>(FP))
-      runFunction(F, None);
+      runFunction(F, std::nullopt);
 
     // FIXME: It is marginally lame that we just do nothing here if we see an
     // entry we don't recognize. It might not be unreasonable for the verifier

llvm/lib/ExecutionEngine/Interpreter/Interpreter.cpp

@@ -69,7 +69,7 @@ Interpreter::~Interpreter() {
 
 void Interpreter::runAtExitHandlers () {
   while (!AtExitHandlers.empty()) {
-    callFunction(AtExitHandlers.back(), None);
+    callFunction(AtExitHandlers.back(), std::nullopt);
     AtExitHandlers.pop_back();
     run();
   }

llvm/lib/ExecutionEngine/JITLink/COFFLinkGraphBuilder.cpp

@@ -613,7 +613,7 @@ COFFLinkGraphBuilder::exportCOMDATSymbol(COFFSymbolIndex SymIndex,
   setGraphSymbol(Symbol.getSectionNumber(), PendingComdatExport->SymbolIndex,
                  *GSym);
   DefinedSymbols[SymbolName] = GSym;
-  PendingComdatExport = None;
+  PendingComdatExport = std::nullopt;
   return GSym;
 }
 

llvm/lib/ExecutionEngine/JITLink/JITLink.cpp

@@ -195,7 +195,7 @@ Block &LinkGraph::splitBlock(Block &B, size_t SplitIndex,
     SplitBlockCache LocalBlockSymbolsCache;
     if (!Cache)
       Cache = &LocalBlockSymbolsCache;
-    if (*Cache == None) {
+    if (*Cache == std::nullopt) {
       *Cache = SplitBlockCache::value_type();
       for (auto *Sym : B.getSection().symbols())
         if (&Sym->getBlock() == &B)

llvm/lib/ExecutionEngine/Orc/COFFVCRuntimeSupport.cpp

@@ -157,8 +157,8 @@ COFFVCRuntimeBootstrapper::getMSVCToolchainPath() {
   std::string VCToolChainPath;
   ToolsetLayout VSLayout;
   IntrusiveRefCntPtr<vfs::FileSystem> VFS = vfs::getRealFileSystem();
-  if (!findVCToolChainViaCommandLine(*VFS, None, None, None, VCToolChainPath,
-                                     VSLayout) &&
+  if (!findVCToolChainViaCommandLine(*VFS, std::nullopt, std::nullopt,
+                                     std::nullopt, VCToolChainPath, VSLayout) &&
       !findVCToolChainViaEnvironment(*VFS, VCToolChainPath, VSLayout) &&
       !findVCToolChainViaSetupConfig(*VFS, VCToolChainPath, VSLayout) &&
       !findVCToolChainViaRegistry(VCToolChainPath, VSLayout))
@@ -167,8 +167,8 @@ COFFVCRuntimeBootstrapper::getMSVCToolchainPath() {
 
   std::string UniversalCRTSdkPath;
   std::string UCRTVersion;
-  if (!getUniversalCRTSdkDir(*VFS, None, None, None, UniversalCRTSdkPath,
-                             UCRTVersion))
+  if (!getUniversalCRTSdkDir(*VFS, std::nullopt, std::nullopt, std::nullopt,
+                             UniversalCRTSdkPath, UCRTVersion))
     return make_error<StringError>("Couldn't find universal sdk.",
                                    inconvertibleErrorCode());
 

llvm/lib/ExecutionEngine/Orc/CompileOnDemandLayer.cpp

@@ -109,7 +109,7 @@ CompileOnDemandLayer::compileRequested(GlobalValueSet Requested) {
 
 Optional<CompileOnDemandLayer::GlobalValueSet>
 CompileOnDemandLayer::compileWholeModule(GlobalValueSet Requested) {
-  return None;
+  return std::nullopt;
 }
 
 CompileOnDemandLayer::CompileOnDemandLayer(
@@ -287,7 +287,7 @@ void CompileOnDemandLayer::emitPartition(
   // Take a 'None' partition to mean the whole module (as opposed to an empty
   // partition, which means "materialize nothing"). Emit the whole module
   // unmodified to the base layer.
-  if (GVsToExtract == None) {
+  if (GVsToExtract == std::nullopt) {
     Defs.clear();
     BaseLayer.emit(std::move(R), std::move(TSM));
     return;

llvm/lib/ExecutionEngine/Orc/ObjectFileInterface.cpp

@@ -179,7 +179,7 @@ getCOFFObjectFileSymbolInfo(ExecutionSession &ES,
       if (Def->Selection != COFF::IMAGE_COMDAT_SELECT_NODUPLICATES) {
         IsWeak = true;
       }
-      ComdatDefs[COFFSym.getSectionNumber()] = None;
+      ComdatDefs[COFFSym.getSectionNumber()] = std::nullopt;
     } else {
       // Skip symbols not defined in this object file.
       if (*SymFlagsOrErr & object::BasicSymbolRef::SF_Undefined)

llvm/lib/ExecutionEngine/Orc/SpeculateAnalyses.cpp

@@ -97,7 +97,7 @@ BlockFreqQuery::ResultTy BlockFreqQuery::operator()(Function &F) {
   auto IBBs = findBBwithCalls(F);
 
   if (IBBs.empty())
-    return None;
+    return std::nullopt;
 
   auto &BFI = FAM.getResult<BlockFrequencyAnalysis>(F);
 
@@ -288,7 +288,7 @@ SpeculateQuery::ResultTy SequenceBBQuery::operator()(Function &F) {
 
   CallerBlocks = findBBwithCalls(F);
   if (CallerBlocks.empty())
-    return None;
+    return std::nullopt;
 
   if (isStraightLine(F))
     SequencedBlocks = rearrangeBB(F, CallerBlocks);

llvm/lib/FileCheck/FileCheck.cpp

@@ -702,7 +702,7 @@ Pattern::parseCallExpr(StringRef &Expr, StringRef FuncName,
                      .Case("min", min)
                      .Case("mul", operator*)
                      .Case("sub", operator-)
-                     .Default(None);
+                     .Default(std::nullopt);
 
   if (!OptFunc)
     return ErrorDiagnostic::get(
@@ -770,7 +770,7 @@ Expected<std::unique_ptr<Expression>> Pattern::parseNumericSubstitutionBlock(
     FileCheckPatternContext *Context, const SourceMgr &SM) {
   std::unique_ptr<ExpressionAST> ExpressionASTPointer = nullptr;
   StringRef DefExpr = StringRef();
-  DefinedNumericVariable = None;
+  DefinedNumericVariable = std::nullopt;
   ExpressionFormat ExplicitFormat = ExpressionFormat();
   unsigned Precision = 0;
 
@@ -2703,8 +2703,9 @@ Error FileCheckPatternContext::defineCmdlineVariables(
       StringRef CmdlineDefExpr = CmdlineDef.substr(1);
       Optional<NumericVariable *> DefinedNumericVariable;
       Expected<std::unique_ptr<Expression>> ExpressionResult =
-          Pattern::parseNumericSubstitutionBlock(
-              CmdlineDefExpr, DefinedNumericVariable, false, None, this, SM);
+          Pattern::parseNumericSubstitutionBlock(CmdlineDefExpr,
+                                                 DefinedNumericVariable, false,
+                                                 std::nullopt, this, SM);
       if (!ExpressionResult) {
         Errs = joinErrors(std::move(Errs), ExpressionResult.takeError());
         continue;

llvm/lib/FileCheck/FileCheckImpl.h

@@ -282,7 +282,7 @@ public:
   /// defined at line \p DefLineNumber or defined before input is parsed if
   /// \p DefLineNumber is None.
   explicit NumericVariable(StringRef Name, ExpressionFormat ImplicitFormat,
-                           Optional<size_t> DefLineNumber = None)
+                           Optional<size_t> DefLineNumber = std::nullopt)
       : Name(Name), ImplicitFormat(ImplicitFormat),
         DefLineNumber(DefLineNumber) {}
 
@@ -306,7 +306,7 @@ public:
   /// buffer string from which it was parsed to \p NewStrValue.  See comments on
   /// getStringValue for a discussion of when the latter can be None.
   void setValue(ExpressionValue NewValue,
-                Optional<StringRef> NewStrValue = None) {
+                Optional<StringRef> NewStrValue = std::nullopt) {
     Value = NewValue;
     StrValue = NewStrValue;
   }
@@ -314,8 +314,8 @@ public:
   /// Clears value of this numeric variable, regardless of whether it is
   /// currently defined or not.
   void clearValue() {
-    Value = None;
-    StrValue = None;
+    Value = std::nullopt;
+    StrValue = std::nullopt;
   }
 
   /// \returns the line number where this variable is defined, if any, or None
@@ -555,7 +555,7 @@ public:
   SMRange getRange() const { return Range; }
 
   static Error get(const SourceMgr &SM, SMLoc Loc, const Twine &ErrMsg,
-                   SMRange Range = None) {
+                   SMRange Range = std::nullopt) {
     return make_error<ErrorDiagnostic>(
         SM.GetMessage(Loc, SourceMgr::DK_Error, ErrMsg), Range);
   }
@@ -682,7 +682,7 @@ class Pattern {
 
 public:
   Pattern(Check::FileCheckType Ty, FileCheckPatternContext *Context,
-          Optional<size_t> Line = None)
+          Optional<size_t> Line = std::nullopt)
       : Context(Context), CheckTy(Ty), LineNumber(Line) {}
 
   /// \returns the location in source code.

llvm/lib/Frontend/OpenMP/OMPContext.cpp

@@ -169,13 +169,13 @@ static int isVariantApplicableInContextHelper(
     if (MK == MK_ANY) {
       if (WasFound)
         return true;
-      return None;
+      return std::nullopt;
     }
 
     // In "all" or "none" mode we accept a matching or non-matching property
     // respectively and move on. We are not done yet!
     if ((WasFound && MK == MK_ALL) || (!WasFound && MK == MK_NONE))
-      return None;
+      return std::nullopt;
 
     // We missed a property, provide some debug output and indicate failure.
     LLVM_DEBUG({

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

@@ -3194,8 +3194,8 @@ createTargetMachine(Function *F, CodeGenOpt::Level OptLevel) {
 
   llvm::TargetOptions Options;
   return std::unique_ptr<TargetMachine>(TheTarget->createTargetMachine(
-      Triple, CPU, Features, Options, /*RelocModel=*/None, /*CodeModel=*/None,
-      OptLevel));
+      Triple, CPU, Features, Options, /*RelocModel=*/std::nullopt,
+      /*CodeModel=*/std::nullopt, OptLevel));
 }
 
 /// Heuristically determine the best-performant unroll factor for \p CLI. This
@@ -3240,12 +3240,12 @@ static int32_t computeHeuristicUnrollFactor(CanonicalLoopInfo *CLI) {
       gatherUnrollingPreferences(L, SE, TTI,
                                  /*BlockFrequencyInfo=*/nullptr,
                                  /*ProfileSummaryInfo=*/nullptr, ORE, OptLevel,
-                                 /*UserThreshold=*/None,
-                                 /*UserCount=*/None,
+                                 /*UserThreshold=*/std::nullopt,
+                                 /*UserCount=*/std::nullopt,
                                  /*UserAllowPartial=*/true,
                                  /*UserAllowRuntime=*/true,
-                                 /*UserUpperBound=*/None,
-                                 /*UserFullUnrollMaxCount=*/None);
+                                 /*UserUpperBound=*/std::nullopt,
+                                 /*UserFullUnrollMaxCount=*/std::nullopt);
 
   UP.Force = true;
 

llvm/lib/FuzzMutate/IRMutator.cpp

@@ -106,7 +106,7 @@ InjectorIRStrategy::chooseOperation(Value *Src, RandomIRBuilder &IB) {
   };
   auto RS = makeSampler(IB.Rand, make_filter_range(Operations, OpMatchesPred));
   if (RS.isEmpty())
-    return None;
+    return std::nullopt;
   return *RS;
 }
 

llvm/lib/FuzzMutate/Operations.cpp

@@ -163,7 +163,7 @@ OpDescriptor llvm::fuzzerop::splitBlockDescriptor(unsigned Weight) {
   SourcePred isInt1Ty{[](ArrayRef<Value *>, const Value *V) {
                         return V->getType()->isIntegerTy(1);
                       },
-                      None};
+                      std::nullopt};
   return {Weight, {isInt1Ty}, buildSplitBlock};
 }
 
@@ -182,7 +182,7 @@ OpDescriptor llvm::fuzzerop::gepDescriptor(unsigned Weight) {
   // TODO: Try to avoid meaningless accesses.
   SourcePred sizedType(
       [](ArrayRef<Value *>, const Value *V) { return V->getType()->isSized(); },
-      None);
+      std::nullopt);
   return {Weight, {sizedPtrType(), sizedType, anyIntType()}, buildGEP};
 }
 

llvm/lib/LTO/LTOCodeGenerator.cpp

@@ -134,7 +134,7 @@ LTOCodeGenerator::LTOCodeGenerator(LLVMContext &Context)
   Context.setDiscardValueNames(LTODiscardValueNames);
   Context.enableDebugTypeODRUniquing();
 
-  Config.CodeModel = None;
+  Config.CodeModel = std::nullopt;
   Config.StatsFile = LTOStatsFile;
   Config.PreCodeGenPassesHook = [](legacy::PassManager &PM) {
     PM.add(createObjCARCContractPass());
@@ -446,7 +446,7 @@ std::unique_ptr<TargetMachine> LTOCodeGenerator::createTargetMachine() {
   assert(MArch && "MArch is not set!");
   return std::unique_ptr<TargetMachine>(MArch->createTargetMachine(
       TripleStr, Config.CPU, FeatureStr, Config.Options, Config.RelocModel,
-      None, Config.CGOptLevel));
+      std::nullopt, Config.CGOptLevel));
 }
 
 // If a linkonce global is present in the MustPreserveSymbols, we need to make

llvm/lib/LTO/LTOModule.cpp

@@ -229,8 +229,8 @@ LTOModule::makeLTOModule(MemoryBufferRef Buffer, const TargetOptions &options,
       CPU = "cyclone";
   }
 
-  TargetMachine *target =
-      march->createTargetMachine(TripleStr, CPU, FeatureStr, options, None);
+  TargetMachine *target = march->createTargetMachine(TripleStr, CPU, FeatureStr,
+                                                     options, std::nullopt);
 
   std::unique_ptr<LTOModule> Ret(new LTOModule(std::move(M), Buffer, target));
   Ret->parseSymbols();

llvm/lib/LTO/ThinLTOCodeGenerator.cpp

@@ -618,7 +618,7 @@ std::unique_ptr<TargetMachine> TargetMachineBuilder::create() const {
 
   std::unique_ptr<TargetMachine> TM(
       TheTarget->createTargetMachine(TheTriple.str(), MCpu, FeatureStr, Options,
-                                     RelocModel, None, CGOptLevel));
+                                     RelocModel, std::nullopt, CGOptLevel));
   assert(TM && "Cannot create target machine");
 
   return TM;

llvm/lib/LineEditor/LineEditor.cpp

@@ -255,7 +255,7 @@ Optional<std::string> LineEditor::readLine() const {
 
   // Either of these may mean end-of-file.
   if (!Line || LineLen == 0)
-    return None;
+    return std::nullopt;
 
   // Strip any newlines off the end of the string.
   while (LineLen > 0 &&

llvm/lib/MC/ELFObjectWriter.cpp

@@ -1056,7 +1056,7 @@ void ELFWriter::writeSectionHeader(
   // Null section first.
   uint64_t FirstSectionSize =
       (NumSections + 1) >= ELF::SHN_LORESERVE ? NumSections + 1 : 0;
-  WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, 0, 0, None, 0);
+  WriteSecHdrEntry(0, 0, 0, 0, 0, FirstSectionSize, 0, 0, std::nullopt, 0);
 
   for (const MCSectionELF *Section : SectionTable) {
     uint32_t GroupSymbolIndex;

llvm/lib/MC/MCAsmBackend.cpp

@@ -75,7 +75,7 @@ MCAsmBackend::createDwoObjectWriter(raw_pwrite_stream &OS,
 }
 
 Optional<MCFixupKind> MCAsmBackend::getFixupKind(StringRef Name) const {
-  return None;
+  return std::nullopt;
 }
 
 const MCFixupKindInfo &MCAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {

llvm/lib/MC/MCAsmStreamer.cpp

@@ -266,12 +266,10 @@ public:
   void emitFileDirective(StringRef Filename) override;
   void emitFileDirective(StringRef Filename, StringRef CompilerVerion,
                          StringRef TimeStamp, StringRef Description) override;
-  Expected<unsigned> tryEmitDwarfFileDirective(unsigned FileNo,
-                                               StringRef Directory,
-                                               StringRef Filename,
-                                               Optional<MD5::MD5Result> Checksum = None,
-                                               Optional<StringRef> Source = None,
-                                               unsigned CUID = 0) override;
+  Expected<unsigned> tryEmitDwarfFileDirective(
+      unsigned FileNo, StringRef Directory, StringRef Filename,
+      Optional<MD5::MD5Result> Checksum = std::nullopt,
+      Optional<StringRef> Source = std::nullopt, unsigned CUID = 0) override;
   void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
                                Optional<MD5::MD5Result> Checksum,
                                Optional<StringRef> Source,
@@ -1499,7 +1497,7 @@ void MCAsmStreamer::emitCodeAlignment(Align Alignment,
     emitAlignmentDirective(Alignment.value(), MAI->getTextAlignFillValue(), 1,
                            MaxBytesToEmit);
   else
-    emitAlignmentDirective(Alignment.value(), None, 1, MaxBytesToEmit);
+    emitAlignmentDirective(Alignment.value(), std::nullopt, 1, MaxBytesToEmit);
 }
 
 void MCAsmStreamer::emitValueToOffset(const MCExpr *Offset,
@@ -2383,7 +2381,7 @@ MCAsmStreamer::emitRelocDirective(const MCExpr &Offset, StringRef Name,
     Expr->print(OS, MAI);
   }
   EmitEOL();
-  return None;
+  return std::nullopt;
 }
 
 void MCAsmStreamer::emitAddrsig() {

llvm/lib/MC/MCCodeView.cpp

@@ -318,9 +318,9 @@ std::pair<size_t, size_t> CodeViewContext::getLineExtent(unsigned FuncId) {
 
 ArrayRef<MCCVLoc> CodeViewContext::getLinesForExtent(size_t L, size_t R) {
   if (R <= L)
-    return None;
+    return std::nullopt;
   if (L >= MCCVLines.size())
-    return None;
+    return std::nullopt;
   return makeArrayRef(&MCCVLines[L], R - L);
 }
 

llvm/lib/MC/MCContext.cpp

@@ -639,7 +639,8 @@ Optional<unsigned> MCContext::getELFUniqueIDForEntsize(StringRef SectionName,
                                                        unsigned EntrySize) {
   auto I = ELFEntrySizeMap.find(
       MCContext::ELFEntrySizeKey{SectionName, Flags, EntrySize});
-  return (I != ELFEntrySizeMap.end()) ? Optional<unsigned>(I->second) : None;
+  return (I != ELFEntrySizeMap.end()) ? Optional<unsigned>(I->second)
+                                      : std::nullopt;
 }
 
 MCSectionGOFF *MCContext::getGOFFSection(StringRef Section, SectionKind Kind,
@@ -960,7 +961,7 @@ void MCContext::setGenDwarfRootFile(StringRef InputFileName, StringRef Buffer) {
       FileName = FileName.drop_front();
   assert(!FileName.empty());
   setMCLineTableRootFile(
-      /*CUID=*/0, getCompilationDir(), FileName, Cksum, None);
+      /*CUID=*/0, getCompilationDir(), FileName, Cksum, std::nullopt);
 }
 
 /// getDwarfFile - takes a file name and number to place in the dwarf file and

llvm/lib/MC/MCDisassembler/MCDisassembler.cpp

@@ -17,7 +17,7 @@ Optional<MCDisassembler::DecodeStatus>
 MCDisassembler::onSymbolStart(SymbolInfoTy &Symbol, uint64_t &Size,
                               ArrayRef<uint8_t> Bytes, uint64_t Address,
                               raw_ostream &CStream) const {
-  return None;
+  return std::nullopt;
 }
 
 uint64_t MCDisassembler::suggestBytesToSkip(ArrayRef<uint8_t> Bytes,

llvm/lib/MC/MCDwarf.cpp

@@ -284,9 +284,9 @@ void MCDwarfDwoLineTable::Emit(MCStreamer &MCOS, MCDwarfLineTableParams Params,
                                MCSection *Section) const {
   if (!HasSplitLineTable)
     return;
-  Optional<MCDwarfLineStr> NoLineStr(None);
+  Optional<MCDwarfLineStr> NoLineStr(std::nullopt);
   MCOS.switchSection(Section);
-  MCOS.emitLabel(Header.Emit(&MCOS, Params, None, NoLineStr).second);
+  MCOS.emitLabel(Header.Emit(&MCOS, Params, std::nullopt, NoLineStr).second);
 }
 
 std::pair<MCSymbol *, MCSymbol *>
@@ -594,7 +594,7 @@ MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
   // If any files have embedded source, they all must.
   if (MCDwarfFiles.empty()) {
     trackMD5Usage(Checksum.has_value());
-    HasSource = (Source != None);
+    HasSource = (Source != std::nullopt);
   }
   if (DwarfVersion >= 5 && isRootFile(RootFile, Directory, FileName, Checksum))
     return 0;
@@ -622,7 +622,7 @@ MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
                                    inconvertibleErrorCode());
 
   // If any files have embedded source, they all must.
-  if (HasSource != (Source != None))
+  if (HasSource != (Source != std::nullopt))
     return make_error<StringError>("inconsistent use of embedded source",
                                    inconvertibleErrorCode());
 

llvm/lib/MC/MCInstrAnalysis.cpp

@@ -33,11 +33,11 @@ bool MCInstrAnalysis::evaluateBranch(const MCInst & /*Inst*/, uint64_t /*Addr*/,
 Optional<uint64_t> MCInstrAnalysis::evaluateMemoryOperandAddress(
     const MCInst &Inst, const MCSubtargetInfo *STI, uint64_t Addr,
     uint64_t Size) const {
-  return None;
+  return std::nullopt;
 }
 
 Optional<uint64_t>
 MCInstrAnalysis::getMemoryOperandRelocationOffset(const MCInst &Inst,
                                                   uint64_t Size) const {
-  return None;
+  return std::nullopt;
 }

llvm/lib/MC/MCObjectFileInfo.cpp

@@ -972,47 +972,53 @@ void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
   // sections, and the individual DWARF sections are distinguished by their
   // section subtype.
   DwarfAbbrevSection = Ctx->getXCOFFSection(
-      ".dwabrev", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwabrev", SectionKind::getMetadata(),
+      /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwabrev", XCOFF::SSUBTYP_DWABREV);
 
   DwarfInfoSection = Ctx->getXCOFFSection(
-      ".dwinfo", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwinfo", SectionKind::getMetadata(), /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwinfo", XCOFF::SSUBTYP_DWINFO);
 
   DwarfLineSection = Ctx->getXCOFFSection(
-      ".dwline", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwline", SectionKind::getMetadata(), /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwline", XCOFF::SSUBTYP_DWLINE);
 
   DwarfFrameSection = Ctx->getXCOFFSection(
-      ".dwframe", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwframe", SectionKind::getMetadata(),
+      /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwframe", XCOFF::SSUBTYP_DWFRAME);
 
   DwarfPubNamesSection = Ctx->getXCOFFSection(
-      ".dwpbnms", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwpbnms", SectionKind::getMetadata(),
+      /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwpbnms", XCOFF::SSUBTYP_DWPBNMS);
 
   DwarfPubTypesSection = Ctx->getXCOFFSection(
-      ".dwpbtyp", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwpbtyp", SectionKind::getMetadata(),
+      /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwpbtyp", XCOFF::SSUBTYP_DWPBTYP);
 
   DwarfStrSection = Ctx->getXCOFFSection(
-      ".dwstr", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwstr", SectionKind::getMetadata(), /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwstr", XCOFF::SSUBTYP_DWSTR);
 
   DwarfLocSection = Ctx->getXCOFFSection(
-      ".dwloc", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwloc", SectionKind::getMetadata(), /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwloc", XCOFF::SSUBTYP_DWLOC);
 
   DwarfARangesSection = Ctx->getXCOFFSection(
-      ".dwarnge", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwarnge", SectionKind::getMetadata(),
+      /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwarnge", XCOFF::SSUBTYP_DWARNGE);
 
   DwarfRangesSection = Ctx->getXCOFFSection(
-      ".dwrnges", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwrnges", SectionKind::getMetadata(),
+      /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwrnges", XCOFF::SSUBTYP_DWRNGES);
 
   DwarfMacinfoSection = Ctx->getXCOFFSection(
-      ".dwmac", SectionKind::getMetadata(), /* CsectProperties */ None,
+      ".dwmac", SectionKind::getMetadata(), /* CsectProperties */ std::nullopt,
       /* MultiSymbolsAllowed */ true, ".dwmac", XCOFF::SSUBTYP_DWMAC);
 }
 

llvm/lib/MC/MCObjectStreamer.cpp

@@ -154,7 +154,7 @@ static Optional<uint64_t> absoluteSymbolDiff(const MCSymbol *Hi,
   assert(Hi && Lo);
   if (!Hi->getFragment() || Hi->getFragment() != Lo->getFragment() ||
       Hi->isVariable() || Lo->isVariable())
-    return None;
+    return std::nullopt;
 
   return Hi->getOffset() - Lo->getOffset();
 }
@@ -746,7 +746,7 @@ getOffsetAndDataFragment(const MCSymbol &Symbol, uint32_t &RelocOffset,
                               std::string("symbol in offset has no data "
                                           "fragment"));
       DF = cast<MCDataFragment>(Fragment);
-      return None;
+      return std::nullopt;
     }
 
     if (OffsetVal.getSymB())
@@ -785,7 +785,7 @@ getOffsetAndDataFragment(const MCSymbol &Symbol, uint32_t &RelocOffset,
                                         "fragment"));
     DF = cast<MCDataFragment>(Fragment);
   }
-  return None;
+  return std::nullopt;
 }
 
 Optional<std::pair<bool, std::string>>
@@ -814,7 +814,7 @@ MCObjectStreamer::emitRelocDirective(const MCExpr &Offset, StringRef Name,
       return std::make_pair(false, std::string(".reloc offset is negative"));
     DF->getFixups().push_back(
         MCFixup::create(OffsetVal.getConstant(), Expr, Kind, Loc));
-    return None;
+    return std::nullopt;
   }
   if (OffsetVal.getSymB())
     return std::make_pair(false,
@@ -827,19 +827,19 @@ MCObjectStreamer::emitRelocDirective(const MCExpr &Offset, StringRef Name,
     Optional<std::pair<bool, std::string>> Error;
     Error = getOffsetAndDataFragment(Symbol, SymbolOffset, DF);
 
-    if (Error != None)
+    if (Error != std::nullopt)
       return Error;
 
     DF->getFixups().push_back(
         MCFixup::create(SymbolOffset + OffsetVal.getConstant(),
                         Expr, Kind, Loc));
-    return None;
+    return std::nullopt;
   }
 
   PendingFixups.emplace_back(
       &SRE.getSymbol(), DF,
       MCFixup::create(OffsetVal.getConstant(), Expr, Kind, Loc));
-  return None;
+  return std::nullopt;
 }
 
 void MCObjectStreamer::emitFill(const MCExpr &NumBytes, uint64_t FillValue,

llvm/lib/MC/MCParser/AsmParser.cpp

@@ -237,9 +237,11 @@ public:
     AssemblerDialect = i;
   }
 
-  void Note(SMLoc L, const Twine &Msg, SMRange Range = None) override;
-  bool Warning(SMLoc L, const Twine &Msg, SMRange Range = None) override;
-  bool printError(SMLoc L, const Twine &Msg, SMRange Range = None) override;
+  void Note(SMLoc L, const Twine &Msg, SMRange Range = std::nullopt) override;
+  bool Warning(SMLoc L, const Twine &Msg,
+               SMRange Range = std::nullopt) override;
+  bool printError(SMLoc L, const Twine &Msg,
+                  SMRange Range = std::nullopt) override;
 
   const AsmToken &Lex() override;
 
@@ -322,7 +324,7 @@ private:
 
   void printMacroInstantiations();
   void printMessage(SMLoc Loc, SourceMgr::DiagKind Kind, const Twine &Msg,
-                    SMRange Range = None) const {
+                    SMRange Range = std::nullopt) const {
     ArrayRef<SMRange> Ranges(Range);
     SrcMgr.PrintMessage(Loc, Kind, Msg, Ranges);
   }
@@ -949,10 +951,9 @@ bool AsmParser::enabledGenDwarfForAssembly() {
     // Use the first #line directive for this, if any. It's preprocessed, so
     // there is no checksum, and of course no source directive.
     if (!FirstCppHashFilename.empty())
-      getContext().setMCLineTableRootFile(/*CUID=*/0,
-                                          getContext().getCompilationDir(),
-                                          FirstCppHashFilename,
-                                          /*Cksum=*/None, /*Source=*/None);
+      getContext().setMCLineTableRootFile(
+          /*CUID=*/0, getContext().getCompilationDir(), FirstCppHashFilename,
+          /*Cksum=*/std::nullopt, /*Source=*/std::nullopt);
     const MCDwarfFile &RootFile =
         getContext().getMCDwarfLineTable(/*CUID=*/0).getRootFile();
     getContext().setGenDwarfFileNumber(getStreamer().emitDwarfFileDirective(
@@ -5698,7 +5699,8 @@ bool AsmParser::parseDirectiveRept(SMLoc DirectiveLoc, StringRef Dir) {
   raw_svector_ostream OS(Buf);
   while (Count--) {
     // Note that the AtPseudoVariable is disabled for instantiations of .rep(t).
-    if (expandMacro(OS, M->Body, None, None, false, getTok().getLoc()))
+    if (expandMacro(OS, M->Body, std::nullopt, std::nullopt, false,
+                    getTok().getLoc()))
       return true;
   }
   instantiateMacroLikeBody(M, DirectiveLoc, OS);

llvm/lib/MC/MCParser/MasmParser.cpp

@@ -510,9 +510,11 @@ public:
     AssemblerDialect = i;
   }
 
-  void Note(SMLoc L, const Twine &Msg, SMRange Range = None) override;
-  bool Warning(SMLoc L, const Twine &Msg, SMRange Range = None) override;
-  bool printError(SMLoc L, const Twine &Msg, SMRange Range = None) override;
+  void Note(SMLoc L, const Twine &Msg, SMRange Range = std::nullopt) override;
+  bool Warning(SMLoc L, const Twine &Msg,
+               SMRange Range = std::nullopt) override;
+  bool printError(SMLoc L, const Twine &Msg,
+                  SMRange Range = std::nullopt) override;
 
   enum ExpandKind { ExpandMacros, DoNotExpandMacros };
   const AsmToken &Lex(ExpandKind ExpandNextToken);
@@ -619,7 +621,7 @@ private:
   bool expandStatement(SMLoc Loc);
 
   void printMessage(SMLoc Loc, SourceMgr::DiagKind Kind, const Twine &Msg,
-                    SMRange Range = None) const {
+                    SMRange Range = std::nullopt) const {
     ArrayRef<SMRange> Ranges(Range);
     SrcMgr.PrintMessage(Loc, Kind, Msg, Ranges);
   }
@@ -1323,10 +1325,9 @@ bool MasmParser::enabledGenDwarfForAssembly() {
     // Use the first #line directive for this, if any. It's preprocessed, so
     // there is no checksum, and of course no source directive.
     if (!FirstCppHashFilename.empty())
-      getContext().setMCLineTableRootFile(/*CUID=*/0,
-                                          getContext().getCompilationDir(),
-                                          FirstCppHashFilename,
-                                          /*Cksum=*/None, /*Source=*/None);
+      getContext().setMCLineTableRootFile(
+          /*CUID=*/0, getContext().getCompilationDir(), FirstCppHashFilename,
+          /*Cksum=*/std::nullopt, /*Source=*/std::nullopt);
     const MCDwarfFile &RootFile =
         getContext().getMCDwarfLineTable(/*CUID=*/0).getRootFile();
     getContext().setGenDwarfFileNumber(getStreamer().emitDwarfFileDirective(
@@ -6991,7 +6992,8 @@ bool MasmParser::parseDirectiveRepeat(SMLoc DirectiveLoc, StringRef Dir) {
   SmallString<256> Buf;
   raw_svector_ostream OS(Buf);
   while (Count--) {
-    if (expandMacro(OS, M->Body, None, None, M->Locals, getTok().getLoc()))
+    if (expandMacro(OS, M->Body, std::nullopt, std::nullopt, M->Locals,
+                    getTok().getLoc()))
       return true;
   }
   instantiateMacroLikeBody(M, DirectiveLoc, OS);
@@ -7024,7 +7026,8 @@ bool MasmParser::parseDirectiveWhile(SMLoc DirectiveLoc) {
   if (Condition) {
     // Instantiate the macro, then resume at this directive to recheck the
     // condition.
-    if (expandMacro(OS, M->Body, None, None, M->Locals, getTok().getLoc()))
+    if (expandMacro(OS, M->Body, std::nullopt, std::nullopt, M->Locals,
+                    getTok().getLoc()))
       return true;
     instantiateMacroLikeBody(M, DirectiveLoc, /*ExitLoc=*/DirectiveLoc, OS);
   }

llvm/lib/MC/MCRegisterInfo.cpp

@@ -84,12 +84,12 @@ Optional<unsigned> MCRegisterInfo::getLLVMRegNum(unsigned RegNum,
   unsigned Size = isEH ? EHDwarf2LRegsSize : Dwarf2LRegsSize;
 
   if (!M)
-    return None;
+    return std::nullopt;
   DwarfLLVMRegPair Key = { RegNum, 0 };
   const DwarfLLVMRegPair *I = std::lower_bound(M, M+Size, Key);
   if (I != M + Size && I->FromReg == RegNum)
     return I->ToReg;
-  return None;
+  return std::nullopt;
 }
 
 int MCRegisterInfo::getDwarfRegNumFromDwarfEHRegNum(unsigned RegNum) const {

llvm/lib/MC/MCSubtargetInfo.cpp

@@ -342,11 +342,11 @@ std::optional<unsigned> MCSubtargetInfo::getCacheSize(unsigned Level) const {
 
 std::optional<unsigned>
 MCSubtargetInfo::getCacheAssociativity(unsigned Level) const {
-  return None;
+  return std::nullopt;
 }
 
 Optional<unsigned> MCSubtargetInfo::getCacheLineSize(unsigned Level) const {
-  return None;
+  return std::nullopt;
 }
 
 unsigned MCSubtargetInfo::getPrefetchDistance() const {

llvm/lib/MC/MCWin64EH.cpp

@@ -287,7 +287,7 @@ static Optional<int64_t> GetOptionalAbsDifference(MCStreamer &Streamer,
   // unusual constructs, like an inline asm with an alignment directive.
   int64_t value;
   if (!Diff->evaluateAsAbsolute(value, OS->getAssembler()))
-    return None;
+    return std::nullopt;
   return value;
 }
 

llvm/lib/ObjCopy/MachO/MachOObject.cpp

@@ -209,7 +209,7 @@ Optional<StringRef> LoadCommand::getSegmentName() const {
   case MachO::LC_SEGMENT_64:
     return extractSegmentName(MLC.segment_command_64_data.segname);
   default:
-    return None;
+    return std::nullopt;
   }
 }
 
@@ -221,6 +221,6 @@ Optional<uint64_t> LoadCommand::getSegmentVMAddr() const {
   case MachO::LC_SEGMENT_64:
     return MLC.segment_command_64_data.vmaddr;
   default:
-    return None;
+    return std::nullopt;
   }
 }

llvm/lib/ObjCopy/MachO/MachOObject.h

@@ -125,7 +125,7 @@ struct SymbolEntry {
   }
 
   Optional<uint32_t> section() const {
-    return n_sect == MachO::NO_SECT ? None : Optional<uint32_t>(n_sect);
+    return n_sect == MachO::NO_SECT ? std::nullopt : Optional<uint32_t>(n_sect);
   }
 };
 

llvm/lib/ObjCopy/MachO/MachOReader.cpp

@@ -333,7 +333,7 @@ void MachOReader::readIndirectSymbolTable(Object &O) const {
   for (uint32_t i = 0; i < DySymTab.nindirectsyms; ++i) {
     uint32_t Index = MachOObj.getIndirectSymbolTableEntry(DySymTab, i);
     if ((Index & AbsOrLocalMask) != 0)
-      O.IndirectSymTable.Symbols.emplace_back(Index, None);
+      O.IndirectSymTable.Symbols.emplace_back(Index, std::nullopt);
     else
       O.IndirectSymTable.Symbols.emplace_back(
           Index, O.SymTable.getSymbolByIndex(Index));

llvm/lib/Object/Archive.cpp

@@ -1158,7 +1158,7 @@ Expected<Optional<Archive::Child>> Archive::findSym(StringRef name) const {
         return MemberOrErr.takeError();
     }
   }
-  return None;
+  return std::nullopt;
 }
 
 // Returns true if archive file contains no member file.

llvm/lib/Object/BuildID.cpp

@@ -54,7 +54,7 @@ Optional<BuildIDRef> getBuildID(const ObjectFile *Obj) {
     return getBuildID(O->getELFFile());
   if (auto *O = dyn_cast<ELFObjectFile<ELF64BE>>(Obj))
     return getBuildID(O->getELFFile());
-  return None;
+  return std::nullopt;
 }
 
 Optional<std::string> BuildIDFetcher::fetch(BuildIDRef BuildID) const {
@@ -86,7 +86,7 @@ Optional<std::string> BuildIDFetcher::fetch(BuildIDRef BuildID) const {
         return std::string(Path);
     }
   }
-  return None;
+  return std::nullopt;
 }
 
 } // namespace object

llvm/lib/Object/ELFObjectFile.cpp

@@ -383,7 +383,7 @@ Optional<StringRef> ELFObjectFileBase::tryGetCPUName() const {
   case ELF::EM_PPC64:
     return StringRef("future");
   default:
-    return None;
+    return std::nullopt;
   }
 }
 
@@ -686,7 +686,7 @@ ELFObjectFileBase::getPltAddresses() const {
     if (PltEntryIter != GotToPlt.end()) {
       symbol_iterator Sym = Relocation.getSymbol();
       if (Sym == symbol_end())
-        Result.emplace_back(None, PltEntryIter->second);
+        Result.emplace_back(std::nullopt, PltEntryIter->second);
       else
         Result.emplace_back(Sym->getRawDataRefImpl(), PltEntryIter->second);
     }

llvm/lib/Object/MachOObjectFile.cpp

@@ -4889,12 +4889,12 @@ MachOObjectFile::getLinkOptHintsLoadCommand() const {
 
 ArrayRef<uint8_t> MachOObjectFile::getDyldInfoRebaseOpcodes() const {
   if (!DyldInfoLoadCmd)
-    return None;
+    return std::nullopt;
 
   auto DyldInfoOrErr =
     getStructOrErr<MachO::dyld_info_command>(*this, DyldInfoLoadCmd);
   if (!DyldInfoOrErr)
-    return None;
+    return std::nullopt;
   MachO::dyld_info_command DyldInfo = DyldInfoOrErr.get();
   const uint8_t *Ptr =
       reinterpret_cast<const uint8_t *>(getPtr(*this, DyldInfo.rebase_off));
@@ -4903,12 +4903,12 @@ ArrayRef<uint8_t> MachOObjectFile::getDyldInfoRebaseOpcodes() const {
 
 ArrayRef<uint8_t> MachOObjectFile::getDyldInfoBindOpcodes() const {
   if (!DyldInfoLoadCmd)
-    return None;
+    return std::nullopt;
 
   auto DyldInfoOrErr =
     getStructOrErr<MachO::dyld_info_command>(*this, DyldInfoLoadCmd);
   if (!DyldInfoOrErr)
-    return None;
+    return std::nullopt;
   MachO::dyld_info_command DyldInfo = DyldInfoOrErr.get();
   const uint8_t *Ptr =
       reinterpret_cast<const uint8_t *>(getPtr(*this, DyldInfo.bind_off));
@@ -4917,12 +4917,12 @@ ArrayRef<uint8_t> MachOObjectFile::getDyldInfoBindOpcodes() const {
 
 ArrayRef<uint8_t> MachOObjectFile::getDyldInfoWeakBindOpcodes() const {
   if (!DyldInfoLoadCmd)
-    return None;
+    return std::nullopt;
 
   auto DyldInfoOrErr =
     getStructOrErr<MachO::dyld_info_command>(*this, DyldInfoLoadCmd);
   if (!DyldInfoOrErr)
-    return None;
+    return std::nullopt;
   MachO::dyld_info_command DyldInfo = DyldInfoOrErr.get();
   const uint8_t *Ptr =
       reinterpret_cast<const uint8_t *>(getPtr(*this, DyldInfo.weak_bind_off));
@@ -4931,12 +4931,12 @@ ArrayRef<uint8_t> MachOObjectFile::getDyldInfoWeakBindOpcodes() const {
 
 ArrayRef<uint8_t> MachOObjectFile::getDyldInfoLazyBindOpcodes() const {
   if (!DyldInfoLoadCmd)
-    return None;
+    return std::nullopt;
 
   auto DyldInfoOrErr =
       getStructOrErr<MachO::dyld_info_command>(*this, DyldInfoLoadCmd);
   if (!DyldInfoOrErr)
-    return None;
+    return std::nullopt;
   MachO::dyld_info_command DyldInfo = DyldInfoOrErr.get();
   const uint8_t *Ptr =
       reinterpret_cast<const uint8_t *>(getPtr(*this, DyldInfo.lazy_bind_off));
@@ -4945,12 +4945,12 @@ ArrayRef<uint8_t> MachOObjectFile::getDyldInfoLazyBindOpcodes() const {
 
 ArrayRef<uint8_t> MachOObjectFile::getDyldInfoExportsTrie() const {
   if (!DyldInfoLoadCmd)
-    return None;
+    return std::nullopt;
 
   auto DyldInfoOrErr =
       getStructOrErr<MachO::dyld_info_command>(*this, DyldInfoLoadCmd);
   if (!DyldInfoOrErr)
-    return None;
+    return std::nullopt;
   MachO::dyld_info_command DyldInfo = DyldInfoOrErr.get();
   const uint8_t *Ptr =
       reinterpret_cast<const uint8_t *>(getPtr(*this, DyldInfo.export_off));
@@ -4961,7 +4961,7 @@ Expected<Optional<MachO::linkedit_data_command>>
 MachOObjectFile::getChainedFixupsLoadCommand() const {
   // Load the dyld chained fixups load command.
   if (!DyldChainedFixupsLoadCmd)
-    return llvm::None;
+    return std::nullopt;
   auto DyldChainedFixupsOrErr = getStructOrErr<MachO::linkedit_data_command>(
       *this, DyldChainedFixupsLoadCmd);
   if (!DyldChainedFixupsOrErr)
@@ -4972,7 +4972,7 @@ MachOObjectFile::getChainedFixupsLoadCommand() const {
   // If the load command is present but the data offset has been zeroed out,
   // as is the case for dylib stubs, return None (no error).
   if (!DyldChainedFixups.dataoff)
-    return llvm::None;
+    return std::nullopt;
   return DyldChainedFixups;
 }
 
@@ -4982,7 +4982,7 @@ MachOObjectFile::getChainedFixupsHeader() const {
   if (!CFOrErr)
     return CFOrErr.takeError();
   if (!CFOrErr->has_value())
-    return llvm::None;
+    return std::nullopt;
 
   const MachO::linkedit_data_command &DyldChainedFixups = **CFOrErr;
 
@@ -5236,12 +5236,12 @@ MachOObjectFile::getDyldChainedFixupTargets() const {
 
 ArrayRef<uint8_t> MachOObjectFile::getDyldExportsTrie() const {
   if (!DyldExportsTrieLoadCmd)
-    return None;
+    return std::nullopt;
 
   auto DyldExportsTrieOrError = getStructOrErr<MachO::linkedit_data_command>(
       *this, DyldExportsTrieLoadCmd);
   if (!DyldExportsTrieOrError)
-    return None;
+    return std::nullopt;
   MachO::linkedit_data_command DyldExportsTrie = DyldExportsTrieOrError.get();
   const uint8_t *Ptr =
       reinterpret_cast<const uint8_t *>(getPtr(*this, DyldExportsTrie.dataoff));
@@ -5265,7 +5265,7 @@ SmallVector<uint64_t> MachOObjectFile::getFunctionStarts() const {
 
 ArrayRef<uint8_t> MachOObjectFile::getUuid() const {
   if (!UuidLoadCmd)
-    return None;
+    return std::nullopt;
   // Returning a pointer is fine as uuid doesn't need endian swapping.
   const char *Ptr = UuidLoadCmd + offsetof(MachO::uuid_command, uuid);
   return makeArrayRef(reinterpret_cast<const uint8_t *>(Ptr), 16);

llvm/lib/Object/Minidump.cpp

@@ -19,7 +19,7 @@ MinidumpFile::getRawStream(minidump::StreamType Type) const {
   auto It = StreamMap.find(Type);
   if (It != StreamMap.end())
     return getRawStream(Streams[It->second]);
-  return None;
+  return std::nullopt;
 }
 
 Expected<std::string> MinidumpFile::getString(size_t Offset) const {

llvm/lib/ObjectYAML/ELFEmitter.cpp

@@ -775,7 +775,7 @@ void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
 
       if (!S->Offset)
         S->Offset = alignToOffset(CBA, sizeof(typename ELFT::uint),
-                                  /*Offset=*/None);
+                                  /*Offset=*/std::nullopt);
       else
         S->Offset = alignToOffset(CBA, /*Align=*/1, S->Offset);
 
@@ -1015,8 +1015,8 @@ void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
 
   assignSectionAddress(SHeader, YAMLSec);
 
-  SHeader.sh_offset =
-      alignToOffset(CBA, SHeader.sh_addralign, RawSec ? RawSec->Offset : None);
+  SHeader.sh_offset = alignToOffset(CBA, SHeader.sh_addralign,
+                                    RawSec ? RawSec->Offset : std::nullopt);
 
   if (RawSec && (RawSec->Content || RawSec->Size)) {
     assert(Symbols.empty());
@@ -1043,7 +1043,7 @@ void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
       dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);
 
   SHeader.sh_offset = alignToOffset(CBA, SHeader.sh_addralign,
-                                    YAMLSec ? YAMLSec->Offset : None);
+                                    YAMLSec ? YAMLSec->Offset : std::nullopt);
 
   if (RawSec && (RawSec->Content || RawSec->Size)) {
     SHeader.sh_size = writeContent(CBA, RawSec->Content, RawSec->Size);
@@ -1097,7 +1097,7 @@ void ELFState<ELFT>::initDWARFSectionHeader(Elf_Shdr &SHeader, StringRef Name,
   SHeader.sh_type = YAMLSec ? YAMLSec->Type : ELF::SHT_PROGBITS;
   SHeader.sh_addralign = YAMLSec ? (uint64_t)YAMLSec->AddressAlign : 1;
   SHeader.sh_offset = alignToOffset(CBA, SHeader.sh_addralign,
-                                    YAMLSec ? YAMLSec->Offset : None);
+                                    YAMLSec ? YAMLSec->Offset : std::nullopt);
 
   ELFYAML::RawContentSection *RawSec =
       dyn_cast_or_null<ELFYAML::RawContentSection>(YAMLSec);

llvm/lib/ObjectYAML/ELFYAML.cpp

@@ -1202,7 +1202,7 @@ struct NormalizedOther {
 
   Optional<uint8_t> denormalize(IO &) {
     if (!Other)
-      return None;
+      return std::nullopt;
     uint8_t Ret = 0;
     for (StOtherPiece &Val : *Other)
       Ret |= toValue(Val);

llvm/lib/Option/ArgList.cpp

@@ -128,7 +128,7 @@ void ArgList::AddAllArgsExcept(ArgStringList &Output,
 /// This is a nicer interface when you don't have a list of Ids to exclude.
 void ArgList::AddAllArgs(ArgStringList &Output,
                          ArrayRef<OptSpecifier> Ids) const {
-  ArrayRef<OptSpecifier> Exclude = None;
+  ArrayRef<OptSpecifier> Exclude = std::nullopt;
   AddAllArgsExcept(Output, Ids, Exclude);
 }
 

llvm/lib/Passes/PassBuilder.cpp

@@ -474,19 +474,19 @@ void PassBuilder::registerLoopAnalyses(LoopAnalysisManager &LAM) {
 
 static std::optional<int> parseRepeatPassName(StringRef Name) {
   if (!Name.consume_front("repeat<") || !Name.consume_back(">"))
-    return None;
+    return std::nullopt;
   int Count;
   if (Name.getAsInteger(0, Count) || Count <= 0)
-    return None;
+    return std::nullopt;
   return Count;
 }
 
 static std::optional<int> parseDevirtPassName(StringRef Name) {
   if (!Name.consume_front("devirt<") || !Name.consume_back(">"))
-    return None;
+    return std::nullopt;
   int Count;
   if (Name.getAsInteger(0, Count) || Count < 0)
-    return None;
+    return std::nullopt;
   return Count;
 }
 
@@ -1060,7 +1060,7 @@ PassBuilder::parsePipelineText(StringRef Text) {
     do {
       // If we try to pop the outer pipeline we have unbalanced parentheses.
       if (PipelineStack.size() == 1)
-        return None;
+        return std::nullopt;
 
       PipelineStack.pop_back();
     } while (Text.consume_front(")"));
@@ -1072,12 +1072,12 @@ PassBuilder::parsePipelineText(StringRef Text) {
     // Otherwise, the end of an inner pipeline always has to be followed by
     // a comma, and then we can continue.
     if (!Text.consume_front(","))
-      return None;
+      return std::nullopt;
   }
 
   if (PipelineStack.size() > 1)
     // Unbalanced paretheses.
-    return None;
+    return std::nullopt;
 
   assert(PipelineStack.back() == &ResultPipeline &&
          "Wrong pipeline at the bottom of the stack!");

llvm/lib/Passes/PassBuilderBindings.cpp

@@ -53,7 +53,7 @@ LLVMErrorRef LLVMRunPasses(LLVMModuleRef M, const char *Passes,
 
   Module *Mod = unwrap(M);
   PassInstrumentationCallbacks PIC;
-  PassBuilder PB(Machine, PassOpts->PTO, None, &PIC);
+  PassBuilder PB(Machine, PassOpts->PTO, std::nullopt, &PIC);
 
   LoopAnalysisManager LAM;
   FunctionAnalysisManager FAM;

llvm/lib/Passes/StandardInstrumentations.cpp

@@ -1877,7 +1877,7 @@ std::string DotCfgChangeReporter::genHTML(StringRef Text, StringRef DotFile,
     return "Unable to find dot executable.";
 
   StringRef Args[] = {DotBinary, "-Tpdf", "-o", PDFFile, DotFile};
-  int Result = sys::ExecuteAndWait(*DotExe, Args, None);
+  int Result = sys::ExecuteAndWait(*DotExe, Args, std::nullopt);
   if (Result < 0)
     return "Error executing system dot.";
 

llvm/lib/ProfileData/Coverage/CoverageMapping.cpp

@@ -558,7 +558,7 @@ class SegmentBuilder {
 
     // Complete any remaining active regions.
     if (!ActiveRegions.empty())
-      completeRegionsUntil(None, 0);
+      completeRegionsUntil(std::nullopt, 0);
   }
 
   /// Sort a nested sequence of regions from a single file.
@@ -684,7 +684,7 @@ static Optional<unsigned> findMainViewFileID(const FunctionRecord &Function) {
       IsNotExpandedFile[CR.ExpandedFileID] = false;
   int I = IsNotExpandedFile.find_first();
   if (I == -1)
-    return None;
+    return std::nullopt;
   return I;
 }
 
@@ -695,7 +695,7 @@ static Optional<unsigned> findMainViewFileID(StringRef SourceFile,
   Optional<unsigned> I = findMainViewFileID(Function);
   if (I && SourceFile == Function.Filenames[*I])
     return I;
-  return None;
+  return std::nullopt;
 }
 
 static bool isExpansion(const CountedRegion &R, unsigned FileID) {

llvm/lib/ProfileData/Coverage/CoverageMappingReader.cpp

@@ -817,8 +817,8 @@ static Error readCoverageMappingData(
   // In Version4, function records are not affixed to coverage headers. Read
   // the records from their dedicated section.
   if (Version >= CovMapVersion::Version4)
-    return Reader->readFunctionRecords(FuncRecBuf, FuncRecBufEnd, None, nullptr,
-                                       nullptr);
+    return Reader->readFunctionRecords(FuncRecBuf, FuncRecBufEnd, std::nullopt,
+                                       nullptr, nullptr);
   return Error::success();
 }
 

llvm/lib/ProfileData/SampleProfReader.cpp

@@ -1824,7 +1824,7 @@ Optional<StringRef>
 SampleProfileReaderItaniumRemapper::lookUpNameInProfile(StringRef Fname) {
   if (auto Key = Remappings->lookup(Fname))
     return NameMap.lookup(Key);
-  return None;
+  return std::nullopt;
 }
 
 /// Prepare a memory buffer for the contents of \p Filename.

llvm/lib/Remarks/BitstreamRemarkParser.cpp

@@ -501,7 +501,7 @@ BitstreamRemarkParser::processRemark(BitstreamRemarkParserHelper &Helper) {
   std::unique_ptr<Remark> Result = std::make_unique<Remark>();
   Remark &R = *Result;
 
-  if (StrTab == None)
+  if (StrTab == std::nullopt)
     return createStringError(
         std::make_error_code(std::errc::invalid_argument),
         "Error while parsing BLOCK_REMARK: missing string table.");

llvm/lib/Remarks/BitstreamRemarkParser.h

@@ -77,8 +77,8 @@ private:
 };
 
 Expected<std::unique_ptr<BitstreamRemarkParser>> createBitstreamParserFromMeta(
-    StringRef Buf, Optional<ParsedStringTable> StrTab = None,
-    Optional<StringRef> ExternalFilePrependPath = None);
+    StringRef Buf, Optional<ParsedStringTable> StrTab = std::nullopt,
+    Optional<StringRef> ExternalFilePrependPath = std::nullopt);
 
 } // end namespace remarks
 } // end namespace llvm

llvm/lib/Remarks/BitstreamRemarkSerializer.cpp

@@ -245,19 +245,19 @@ void BitstreamRemarkSerializerHelper::emitMetaBlock(
 
   switch (ContainerType) {
   case BitstreamRemarkContainerType::SeparateRemarksMeta:
-    assert(StrTab != None && *StrTab != nullptr);
+    assert(StrTab != std::nullopt && *StrTab != nullptr);
     emitMetaStrTab(**StrTab);
-    assert(Filename != None);
+    assert(Filename != std::nullopt);
     emitMetaExternalFile(*Filename);
     break;
   case BitstreamRemarkContainerType::SeparateRemarksFile:
-    assert(RemarkVersion != None);
+    assert(RemarkVersion != std::nullopt);
     emitMetaRemarkVersion(*RemarkVersion);
     break;
   case BitstreamRemarkContainerType::Standalone:
-    assert(RemarkVersion != None);
+    assert(RemarkVersion != std::nullopt);
     emitMetaRemarkVersion(*RemarkVersion);
-    assert(StrTab != None && *StrTab != nullptr);
+    assert(StrTab != std::nullopt && *StrTab != nullptr);
     emitMetaStrTab(**StrTab);
     break;
   }
@@ -297,7 +297,7 @@ void BitstreamRemarkSerializerHelper::emitRemarkBlock(const Remark &Remark,
     R.clear();
     unsigned Key = StrTab.add(Arg.Key).first;
     unsigned Val = StrTab.add(Arg.Val).first;
-    bool HasDebugLoc = Arg.Loc != None;
+    bool HasDebugLoc = Arg.Loc != std::nullopt;
     R.push_back(HasDebugLoc ? RECORD_REMARK_ARG_WITH_DEBUGLOC
                             : RECORD_REMARK_ARG_WITHOUT_DEBUGLOC);
     R.push_back(Key);
@@ -353,7 +353,7 @@ void BitstreamRemarkSerializer::emit(const Remark &Remark) {
         Helper.ContainerType == BitstreamRemarkContainerType::Standalone;
     BitstreamMetaSerializer MetaSerializer(
         OS, Helper,
-        IsStandalone ? &*StrTab : Optional<const StringTable *>(None));
+        IsStandalone ? &*StrTab : Optional<const StringTable *>(std::nullopt));
     MetaSerializer.emit();
     DidSetUp = true;
   }

llvm/lib/Remarks/RemarkLinker.cpp

@@ -78,7 +78,7 @@ Error RemarkLinker::link(StringRef Buffer, Optional<Format> RemarkFormat) {
 
   Expected<std::unique_ptr<RemarkParser>> MaybeParser =
       createRemarkParserFromMeta(
-          *RemarkFormat, Buffer, /*StrTab=*/None,
+          *RemarkFormat, Buffer, /*StrTab=*/std::nullopt,
           PrependPath ? Optional<StringRef>(StringRef(*PrependPath))
                       : Optional<StringRef>());
   if (!MaybeParser)

llvm/lib/Remarks/RemarkParser.cpp

@@ -113,7 +113,7 @@ struct CParser {
   std::optional<std::string> Err;
 
   CParser(Format ParserFormat, StringRef Buf,
-          std::optional<ParsedStringTable> StrTab = None)
+          std::optional<ParsedStringTable> StrTab = std::nullopt)
       : TheParser(cantFail(
             StrTab ? createRemarkParser(ParserFormat, Buf, std::move(*StrTab))
                    : createRemarkParser(ParserFormat, Buf))) {}