[Basic] 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

28 files changed, 100 insertions, 74 deletions

diff --git a/clang/lib/Basic/DarwinSDKInfo.cpp b/clang/lib/Basic/DarwinSDKInfo.cpp
index 64bcb45..ca24120 100644
--- a/clang/lib/Basic/DarwinSDKInfo.cpp
+++ b/clang/lib/Basic/DarwinSDKInfo.cpp
@@ -30,7 +30,7 @@ Optional<VersionTuple> DarwinSDKInfo::RelatedTargetVersionMapping::map(
   if (Key.getMinor())
     return map(VersionTuple(Key.getMajor()), MinimumValue, MaximumValue);
   // If this a major only key, return None for a missing entry.
-  return None;
+  return std::nullopt;
 }
 
 Optional<DarwinSDKInfo::RelatedTargetVersionMapping>
@@ -45,7 +45,7 @@ DarwinSDKInfo::RelatedTargetVersionMapping::parseJSON(
       llvm::VersionTuple KeyVersion;
       llvm::VersionTuple ValueVersion;
       if (KeyVersion.tryParse(KV.getFirst()) || ValueVersion.tryParse(*Val))
-        return None;
+        return std::nullopt;
       Mapping[KeyVersion.normalize()] = ValueVersion;
       if (KeyVersion < Min)
         Min = KeyVersion;
@@ -56,7 +56,7 @@ DarwinSDKInfo::RelatedTargetVersionMapping::parseJSON(
     }
   }
   if (Mapping.empty())
-    return None;
+    return std::nullopt;
   return RelatedTargetVersionMapping(
       Min, Max, MinValue, MaximumDeploymentTarget, std::move(Mapping));
 }
@@ -65,10 +65,10 @@ static Optional<VersionTuple> getVersionKey(const llvm::json::Object &Obj,
                                             StringRef Key) {
   auto Value = Obj.getString(Key);
   if (!Value)
-    return None;
+    return std::nullopt;
   VersionTuple Version;
   if (Version.tryParse(*Value))
-    return None;
+    return std::nullopt;
   return Version;
 }
 
@@ -76,11 +76,11 @@ Optional<DarwinSDKInfo>
 DarwinSDKInfo::parseDarwinSDKSettingsJSON(const llvm::json::Object *Obj) {
   auto Version = getVersionKey(*Obj, "Version");
   if (!Version)
-    return None;
+    return std::nullopt;
   auto MaximumDeploymentVersion =
       getVersionKey(*Obj, "MaximumDeploymentTarget");
   if (!MaximumDeploymentVersion)
-    return None;
+    return std::nullopt;
   llvm::DenseMap<OSEnvPair::StorageType, Optional<RelatedTargetVersionMapping>>
       VersionMappings;
   if (const auto *VM = Obj->getObject("VersionMap")) {
@@ -107,7 +107,7 @@ DarwinSDKInfo::parseDarwinSDKSettingsJSON(const llvm::json::Object *Obj) {
       auto VersionMap = RelatedTargetVersionMapping::parseJSON(
           *Mapping, *MaximumDeploymentVersion);
       if (!VersionMap)
-        return None;
+        return std::nullopt;
       VersionMappings[OSEnvPair::macOStoMacCatalystPair().Value] =
           std::move(VersionMap);
     }
@@ -115,7 +115,7 @@ DarwinSDKInfo::parseDarwinSDKSettingsJSON(const llvm::json::Object *Obj) {
       auto VersionMap = RelatedTargetVersionMapping::parseJSON(
           *Mapping, *MaximumDeploymentVersion);
       if (!VersionMap)
-        return None;
+        return std::nullopt;
       VersionMappings[OSEnvPair::macCatalystToMacOSPair().Value] =
           std::move(VersionMap);
     }
@@ -134,7 +134,7 @@ clang::parseDarwinSDKInfo(llvm::vfs::FileSystem &VFS, StringRef SDKRootPath) {
       VFS.getBufferForFile(Filepath);
   if (!File) {
     // If the file couldn't be read, assume it just doesn't exist.
-    return None;
+    return std::nullopt;
   }
   Expected<llvm::json::Value> Result =
       llvm::json::parse(File.get()->getBuffer());
diff --git a/clang/lib/Basic/DiagnosticIDs.cpp b/clang/lib/Basic/DiagnosticIDs.cpp
index 1695a3c..66f3979 100644
--- a/clang/lib/Basic/DiagnosticIDs.cpp
+++ b/clang/lib/Basic/DiagnosticIDs.cpp
@@ -639,14 +639,14 @@ DiagnosticIDs::getGroupForWarningOption(StringRef Name) {
   const auto *Found = llvm::partition_point(
       OptionTable, [=](const WarningOption &O) { return O.getName() < Name; });
   if (Found == std::end(OptionTable) || Found->getName() != Name)
-    return llvm::None;
+    return std::nullopt;
   return static_cast<diag::Group>(Found - OptionTable);
 }
 
 llvm::Optional<diag::Group> DiagnosticIDs::getGroupForDiag(unsigned DiagID) {
   if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
     return static_cast<diag::Group>(Info->getOptionGroupIndex());
-  return llvm::None;
+  return std::nullopt;
 }
 
 /// getWarningOptionForDiag - Return the lowest-level warning option that
diff --git a/clang/lib/Basic/FileManager.cpp b/clang/lib/Basic/FileManager.cpp
index 4ef2535..69ebd3b 100644
--- a/clang/lib/Basic/FileManager.cpp
+++ b/clang/lib/Basic/FileManager.cpp
@@ -474,7 +474,7 @@ llvm::Optional<FileEntryRef> FileManager::getBypassFile(FileEntryRef VF) {
   // Stat of the file and return nullptr if it doesn't exist.
   llvm::vfs::Status Status;
   if (getStatValue(VF.getName(), Status, /*isFile=*/true, /*F=*/nullptr))
-    return None;
+    return std::nullopt;
 
   if (!SeenBypassFileEntries)
     SeenBypassFileEntries = std::make_unique<
diff --git a/clang/lib/Basic/ProfileList.cpp b/clang/lib/Basic/ProfileList.cpp
index 4c17a54..0f049b1 100644
--- a/clang/lib/Basic/ProfileList.cpp
+++ b/clang/lib/Basic/ProfileList.cpp
@@ -111,7 +111,7 @@ ProfileList::inSection(StringRef Section, StringRef Prefix,
     return Forbid;
   if (SCL->inSection(Section, Prefix, Query))
     return Allow;
-  return None;
+  return std::nullopt;
 }
 
 llvm::Optional<ProfileList::ExclusionType>
@@ -125,7 +125,7 @@ ProfileList::isFunctionExcluded(StringRef FunctionName,
     return Forbid;
   if (SCL->inSection(Section, "fun", FunctionName))
     return Allow;
-  return None;
+  return std::nullopt;
 }
 
 llvm::Optional<ProfileList::ExclusionType>
@@ -145,5 +145,5 @@ ProfileList::isFileExcluded(StringRef FileName,
     return Forbid;
   if (SCL->inSection(Section, "src", FileName))
     return Allow;
-  return None;
+  return std::nullopt;
 }
diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
index a5f673f..44ced42 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -105,11 +105,11 @@ ContentCache::getBufferOrNone(DiagnosticsEngine &Diag, FileManager &FM,
   // Lazily create the Buffer for ContentCaches that wrap files.  If we already
   // computed it, just return what we have.
   if (IsBufferInvalid)
-    return None;
+    return std::nullopt;
   if (Buffer)
     return Buffer->getMemBufferRef();
   if (!ContentsEntry)
-    return None;
+    return std::nullopt;
 
   // Start with the assumption that the buffer is invalid to simplify early
   // return paths.
@@ -131,7 +131,7 @@ ContentCache::getBufferOrNone(DiagnosticsEngine &Diag, FileManager &FM,
       Diag.Report(Loc, diag::err_cannot_open_file)
           << ContentsEntry->getName() << BufferOrError.getError().message();
 
-    return None;
+    return std::nullopt;
   }
 
   Buffer = std::move(*BufferOrError);
@@ -153,7 +153,7 @@ ContentCache::getBufferOrNone(DiagnosticsEngine &Diag, FileManager &FM,
       Diag.Report(Loc, diag::err_file_too_large)
         << ContentsEntry->getName();
 
-    return None;
+    return std::nullopt;
   }
 
   // Unless this is a named pipe (in which case we can handle a mismatch),
@@ -168,7 +168,7 @@ ContentCache::getBufferOrNone(DiagnosticsEngine &Diag, FileManager &FM,
       Diag.Report(Loc, diag::err_file_modified)
         << ContentsEntry->getName();
 
-    return None;
+    return std::nullopt;
   }
 
   // If the buffer is valid, check to see if it has a UTF Byte Order Mark
@@ -180,7 +180,7 @@ ContentCache::getBufferOrNone(DiagnosticsEngine &Diag, FileManager &FM,
   if (InvalidBOM) {
     Diag.Report(Loc, diag::err_unsupported_bom)
       << InvalidBOM << ContentsEntry->getName();
-    return None;
+    return std::nullopt;
   }
 
   // Buffer has been validated.
@@ -720,7 +720,7 @@ SourceManager::bypassFileContentsOverride(FileEntryRef File) {
 
   // If the file can't be found in the FS, give up.
   if (!BypassFile)
-    return None;
+    return std::nullopt;
 
   (void)getOrCreateContentCache(*BypassFile);
   return BypassFile;
@@ -735,7 +735,7 @@ SourceManager::getNonBuiltinFilenameForID(FileID FID) const {
   if (const SrcMgr::SLocEntry *Entry = getSLocEntryForFile(FID))
     if (Entry->getFile().getContentCache().OrigEntry)
       return Entry->getFile().getName();
-  return None;
+  return std::nullopt;
 }
 
 StringRef SourceManager::getBufferData(FileID FID, bool *Invalid) const {
@@ -749,7 +749,7 @@ llvm::Optional<StringRef>
 SourceManager::getBufferDataIfLoaded(FileID FID) const {
   if (const SrcMgr::SLocEntry *Entry = getSLocEntryForFile(FID))
     return Entry->getFile().getContentCache().getBufferDataIfLoaded();
-  return None;
+  return std::nullopt;
 }
 
 llvm::Optional<StringRef> SourceManager::getBufferDataOrNone(FileID FID) const {
@@ -757,7 +757,7 @@ llvm::Optional<StringRef> SourceManager::getBufferDataOrNone(FileID FID) const {
     if (auto B = Entry->getFile().getContentCache().getBufferOrNone(
             Diag, getFileManager(), SourceLocation()))
       return B->getBuffer();
-  return None;
+  return std::nullopt;
 }
 
 //===----------------------------------------------------------------------===//
@@ -2230,7 +2230,7 @@ LLVM_DUMP_METHOD void SourceManager::dump() const {
       DumpSLocEntry(ID, LoadedSLocEntryTable[Index], NextStart);
       NextStart = LoadedSLocEntryTable[Index].getOffset();
     } else {
-      NextStart = None;
+      NextStart = std::nullopt;
     }
   }
 }
diff --git a/clang/lib/Basic/TargetID.cpp b/clang/lib/Basic/TargetID.cpp
index 6f583cb..e50080c 100644
--- a/clang/lib/Basic/TargetID.cpp
+++ b/clang/lib/Basic/TargetID.cpp
@@ -73,7 +73,7 @@ parseTargetIDWithFormatCheckingOnly(llvm::StringRef TargetID,
   auto Split = TargetID.split(':');
   Processor = Split.first;
   if (Processor.empty())
-    return llvm::None;
+    return std::nullopt;
 
   auto Features = Split.second;
   if (Features.empty())
@@ -88,12 +88,12 @@ parseTargetIDWithFormatCheckingOnly(llvm::StringRef TargetID,
     auto Sign = Splits.first.back();
     auto Feature = Splits.first.drop_back();
     if (Sign != '+' && Sign != '-')
-      return llvm::None;
+      return std::nullopt;
     bool IsOn = Sign == '+';
     auto Loc = FeatureMap->find(Feature);
     // Each feature can only show up at most once in target ID.
     if (Loc != FeatureMap->end())
-      return llvm::None;
+      return std::nullopt;
     (*FeatureMap)[Feature] = IsOn;
     Features = Splits.second;
   }
@@ -107,11 +107,11 @@ parseTargetID(const llvm::Triple &T, llvm::StringRef TargetID,
       parseTargetIDWithFormatCheckingOnly(TargetID, FeatureMap);
 
   if (!OptionalProcessor)
-    return llvm::None;
+    return std::nullopt;
 
   llvm::StringRef Processor = getCanonicalProcessorName(T, *OptionalProcessor);
   if (Processor.empty())
-    return llvm::None;
+    return std::nullopt;
 
   llvm::SmallSet<llvm::StringRef, 4> AllFeatures;
   for (auto &&F : getAllPossibleTargetIDFeatures(T, Processor))
@@ -119,7 +119,7 @@ parseTargetID(const llvm::Triple &T, llvm::StringRef TargetID,
 
   for (auto &&F : *FeatureMap)
     if (!AllFeatures.count(F.first()))
-      return llvm::None;
+      return std::nullopt;
 
   return Processor;
 }
@@ -161,7 +161,7 @@ getConflictTargetIDCombination(const std::set<llvm::StringRef> &TargetIDs) {
         return std::make_pair(Loc->second.TargetID, ID);
     }
   }
-  return llvm::None;
+  return std::nullopt;
 }
 
 bool isCompatibleTargetID(llvm::StringRef Provided, llvm::StringRef Requested) {
diff --git a/clang/lib/Basic/Targets/AArch64.cpp b/clang/lib/Basic/Targets/AArch64.cpp
index edc4fdc..476bfcf 100644
--- a/clang/lib/Basic/Targets/AArch64.cpp
+++ b/clang/lib/Basic/Targets/AArch64.cpp
@@ -506,7 +506,7 @@ AArch64TargetInfo::getVScaleRange(const LangOptions &LangOpts) const {
   if (hasFeature("sve"))
     return std::pair<unsigned, unsigned>(1, 16);
 
-  return None;
+  return std::nullopt;
 }
 
 bool AArch64TargetInfo::hasFeature(StringRef Feature) const {
diff --git a/clang/lib/Basic/Targets/AMDGPU.h b/clang/lib/Basic/Targets/AMDGPU.h
index 742bb76..e9bda75 100644
--- a/clang/lib/Basic/Targets/AMDGPU.h
+++ b/clang/lib/Basic/Targets/AMDGPU.h
@@ -119,7 +119,7 @@ public:
   ArrayRef<const char *> getGCCRegNames() const override;
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   /// Accepted register names: (n, m is unsigned integer, n < m)
@@ -402,7 +402,7 @@ public:
     } else if (AddressSpace == Local) {
       return DWARF_Local;
     } else {
-      return None;
+      return std::nullopt;
     }
   }
 
@@ -452,7 +452,7 @@ public:
 
   Optional<std::string> getTargetID() const override {
     if (!isAMDGCN(getTriple()))
-      return llvm::None;
+      return std::nullopt;
     // When -target-cpu is not set, we assume generic code that it is valid
     // for all GPU and use an empty string as target ID to represent that.
     if (GPUKind == llvm::AMDGPU::GK_NONE)
diff --git a/clang/lib/Basic/Targets/ARC.h b/clang/lib/Basic/Targets/ARC.h
index 5411cd2..f3640f3 100644
--- a/clang/lib/Basic/Targets/ARC.h
+++ b/clang/lib/Basic/Targets/ARC.h
@@ -40,7 +40,9 @@ public:
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override;
 
-  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override {
+    return std::nullopt;
+  }
 
   BuiltinVaListKind getBuiltinVaListKind() const override {
     return TargetInfo::VoidPtrBuiltinVaList;
@@ -58,7 +60,7 @@ public:
   }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   bool validateAsmConstraint(const char *&Name,
diff --git a/clang/lib/Basic/Targets/AVR.h b/clang/lib/Basic/Targets/AVR.h
index 8b42144..0b8a05d 100644
--- a/clang/lib/Basic/Targets/AVR.h
+++ b/clang/lib/Basic/Targets/AVR.h
@@ -61,7 +61,9 @@ public:
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override;
 
-  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override {
+    return std::nullopt;
+  }
 
   BuiltinVaListKind getBuiltinVaListKind() const override {
     return TargetInfo::VoidPtrBuiltinVaList;
@@ -78,7 +80,7 @@ public:
   }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   ArrayRef<TargetInfo::AddlRegName> getGCCAddlRegNames() const override {
diff --git a/clang/lib/Basic/Targets/BPF.h b/clang/lib/Basic/Targets/BPF.h
index 393a91f..708bdb4 100644
--- a/clang/lib/Basic/Targets/BPF.h
+++ b/clang/lib/Basic/Targets/BPF.h
@@ -68,7 +68,9 @@ public:
   }
 
   bool isValidGCCRegisterName(StringRef Name) const override { return true; }
-  ArrayRef<const char *> getGCCRegNames() const override { return None; }
+  ArrayRef<const char *> getGCCRegNames() const override {
+    return std::nullopt;
+  }
 
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &Info) const override {
@@ -85,7 +87,7 @@ public:
   }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   bool allowDebugInfoForExternalRef() const override { return true; }
diff --git a/clang/lib/Basic/Targets/DirectX.h b/clang/lib/Basic/Targets/DirectX.h
index 548accf..06cfa79 100644
--- a/clang/lib/Basic/Targets/DirectX.h
+++ b/clang/lib/Basic/Targets/DirectX.h
@@ -70,11 +70,15 @@ public:
     return Feature == "directx";
   }
 
-  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override {
+    return std::nullopt;
+  }
 
   const char *getClobbers() const override { return ""; }
 
-  ArrayRef<const char *> getGCCRegNames() const override { return None; }
+  ArrayRef<const char *> getGCCRegNames() const override {
+    return std::nullopt;
+  }
 
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &info) const override {
@@ -82,7 +86,7 @@ public:
   }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   BuiltinVaListKind getBuiltinVaListKind() const override {
diff --git a/clang/lib/Basic/Targets/Lanai.h b/clang/lib/Basic/Targets/Lanai.h
index 56c6cce..6ab4aea 100644
--- a/clang/lib/Basic/Targets/Lanai.h
+++ b/clang/lib/Basic/Targets/Lanai.h
@@ -78,7 +78,9 @@ public:
     return TargetInfo::VoidPtrBuiltinVaList;
   }
 
-  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override {
+    return std::nullopt;
+  }
 
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &info) const override {
diff --git a/clang/lib/Basic/Targets/Le64.h b/clang/lib/Basic/Targets/Le64.h
index 13a0b04..6652bce 100644
--- a/clang/lib/Basic/Targets/Le64.h
+++ b/clang/lib/Basic/Targets/Le64.h
@@ -43,10 +43,12 @@ public:
 
   const char *getClobbers() const override { return ""; }
 
-  ArrayRef<const char *> getGCCRegNames() const override { return None; }
+  ArrayRef<const char *> getGCCRegNames() const override {
+    return std::nullopt;
+  }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   bool validateAsmConstraint(const char *&Name,
diff --git a/clang/lib/Basic/Targets/M68k.cpp b/clang/lib/Basic/Targets/M68k.cpp
index ada5b97..48627a8 100644
--- a/clang/lib/Basic/Targets/M68k.cpp
+++ b/clang/lib/Basic/Targets/M68k.cpp
@@ -117,7 +117,7 @@ void M68kTargetInfo::getTargetDefines(const LangOptions &Opts,
 
 ArrayRef<Builtin::Info> M68kTargetInfo::getTargetBuiltins() const {
   // FIXME: Implement.
-  return None;
+  return std::nullopt;
 }
 
 bool M68kTargetInfo::hasFeature(StringRef Feature) const {
@@ -136,7 +136,7 @@ ArrayRef<const char *> M68kTargetInfo::getGCCRegNames() const {
 
 ArrayRef<TargetInfo::GCCRegAlias> M68kTargetInfo::getGCCRegAliases() const {
   // No aliases.
-  return None;
+  return std::nullopt;
 }
 
 bool M68kTargetInfo::validateAsmConstraint(
@@ -209,7 +209,7 @@ M68kTargetInfo::handleAsmEscapedChar(char EscChar) const {
     C = 'd';
     break;
   default:
-    return llvm::None;
+    return std::nullopt;
   }
 
   return std::string(1, C);
diff --git a/clang/lib/Basic/Targets/MSP430.h b/clang/lib/Basic/Targets/MSP430.h
index 9d42e4d..973e039 100644
--- a/clang/lib/Basic/Targets/MSP430.h
+++ b/clang/lib/Basic/Targets/MSP430.h
@@ -52,7 +52,7 @@ public:
 
   ArrayRef<Builtin::Info> getTargetBuiltins() const override {
     // FIXME: Implement.
-    return None;
+    return std::nullopt;
   }
 
   bool allowsLargerPreferedTypeAlignment() const override { return false; }
diff --git a/clang/lib/Basic/Targets/NVPTX.h b/clang/lib/Basic/Targets/NVPTX.h
index 176e2e4..79f4cbe 100644
--- a/clang/lib/Basic/Targets/NVPTX.h
+++ b/clang/lib/Basic/Targets/NVPTX.h
@@ -87,7 +87,7 @@ public:
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
     // No aliases.
-    return None;
+    return std::nullopt;
   }
 
   bool validateAsmConstraint(const char *&Name,
@@ -162,7 +162,7 @@ public:
   getDWARFAddressSpace(unsigned AddressSpace) const override {
     if (AddressSpace >= std::size(NVPTXDWARFAddrSpaceMap) ||
         NVPTXDWARFAddrSpaceMap[AddressSpace] < 0)
-      return llvm::None;
+      return std::nullopt;
     return NVPTXDWARFAddrSpaceMap[AddressSpace];
   }
 
diff --git a/clang/lib/Basic/Targets/PNaCl.cpp b/clang/lib/Basic/Targets/PNaCl.cpp
index 60e9467..51b6452 100644
--- a/clang/lib/Basic/Targets/PNaCl.cpp
+++ b/clang/lib/Basic/Targets/PNaCl.cpp
@@ -16,10 +16,12 @@
 using namespace clang;
 using namespace clang::targets;
 
-ArrayRef<const char *> PNaClTargetInfo::getGCCRegNames() const { return None; }
+ArrayRef<const char *> PNaClTargetInfo::getGCCRegNames() const {
+  return std::nullopt;
+}
 
 ArrayRef<TargetInfo::GCCRegAlias> PNaClTargetInfo::getGCCRegAliases() const {
-  return None;
+  return std::nullopt;
 }
 
 void PNaClTargetInfo::getArchDefines(const LangOptions &Opts,
diff --git a/clang/lib/Basic/Targets/PNaCl.h b/clang/lib/Basic/Targets/PNaCl.h
index b5cf73d..72c5863 100644
--- a/clang/lib/Basic/Targets/PNaCl.h
+++ b/clang/lib/Basic/Targets/PNaCl.h
@@ -52,7 +52,9 @@ public:
     return Feature == "pnacl";
   }
 
-  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override {
+    return std::nullopt;
+  }
 
   BuiltinVaListKind getBuiltinVaListKind() const override {
     return TargetInfo::PNaClABIBuiltinVaList;
diff --git a/clang/lib/Basic/Targets/RISCV.cpp b/clang/lib/Basic/Targets/RISCV.cpp
index 2c7e002..b76ef15 100644
--- a/clang/lib/Basic/Targets/RISCV.cpp
+++ b/clang/lib/Basic/Targets/RISCV.cpp
@@ -264,7 +264,7 @@ RISCVTargetInfo::getVScaleRange(const LangOptions &LangOpts) const {
                           MaxVLen / llvm::RISCV::RVVBitsPerBlock);
   }
 
-  return None;
+  return std::nullopt;
 }
 
 /// Return true if has this feature, need to sync with handleTargetFeatures.
@@ -276,7 +276,7 @@ bool RISCVTargetInfo::hasFeature(StringRef Feature) const {
                     .Case("riscv64", Is64Bit)
                     .Case("32bit", !Is64Bit)
                     .Case("64bit", Is64Bit)
-                    .Default(None);
+                    .Default(std::nullopt);
   if (Result)
     return Result.value();
 
diff --git a/clang/lib/Basic/Targets/SPIR.h b/clang/lib/Basic/Targets/SPIR.h
index 655e9d6..17db3b1 100644
--- a/clang/lib/Basic/Targets/SPIR.h
+++ b/clang/lib/Basic/Targets/SPIR.h
@@ -104,11 +104,15 @@ public:
   // memcpy as per section 3 of the SPIR spec.
   bool useFP16ConversionIntrinsics() const override { return false; }
 
-  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override {
+    return std::nullopt;
+  }
 
   const char *getClobbers() const override { return ""; }
 
-  ArrayRef<const char *> getGCCRegNames() const override { return None; }
+  ArrayRef<const char *> getGCCRegNames() const override {
+    return std::nullopt;
+  }
 
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &info) const override {
@@ -116,7 +120,7 @@ public:
   }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   BuiltinVaListKind getBuiltinVaListKind() const override {
diff --git a/clang/lib/Basic/Targets/Sparc.h b/clang/lib/Basic/Targets/Sparc.h
index 177a117..4860b02 100644
--- a/clang/lib/Basic/Targets/Sparc.h
+++ b/clang/lib/Basic/Targets/Sparc.h
@@ -50,7 +50,7 @@ public:
 
   ArrayRef<Builtin::Info> getTargetBuiltins() const override {
     // FIXME: Implement!
-    return None;
+    return std::nullopt;
   }
   BuiltinVaListKind getBuiltinVaListKind() const override {
     return TargetInfo::VoidPtrBuiltinVaList;
diff --git a/clang/lib/Basic/Targets/SystemZ.h b/clang/lib/Basic/Targets/SystemZ.h
index 371eb25..a599413 100644
--- a/clang/lib/Basic/Targets/SystemZ.h
+++ b/clang/lib/Basic/Targets/SystemZ.h
@@ -71,7 +71,7 @@ public:
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
     // No aliases.
-    return None;
+    return std::nullopt;
   }
 
   ArrayRef<TargetInfo::AddlRegName> getGCCAddlRegNames() const override;
diff --git a/clang/lib/Basic/Targets/TCE.h b/clang/lib/Basic/Targets/TCE.h
index fbd0c30..430ace3 100644
--- a/clang/lib/Basic/Targets/TCE.h
+++ b/clang/lib/Basic/Targets/TCE.h
@@ -92,7 +92,9 @@ public:
 
   bool hasFeature(StringRef Feature) const override { return Feature == "tce"; }
 
-  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override {
+    return std::nullopt;
+  }
 
   const char *getClobbers() const override { return ""; }
 
@@ -100,7 +102,9 @@ public:
     return TargetInfo::VoidPtrBuiltinVaList;
   }
 
-  ArrayRef<const char *> getGCCRegNames() const override { return None; }
+  ArrayRef<const char *> getGCCRegNames() const override {
+    return std::nullopt;
+  }
 
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &info) const override {
@@ -108,7 +112,7 @@ public:
   }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 };
 
diff --git a/clang/lib/Basic/Targets/WebAssembly.h b/clang/lib/Basic/Targets/WebAssembly.h
index 6341886..d0b4809 100644
--- a/clang/lib/Basic/Targets/WebAssembly.h
+++ b/clang/lib/Basic/Targets/WebAssembly.h
@@ -96,10 +96,10 @@ private:
     return VoidPtrBuiltinVaList;
   }
 
-  ArrayRef<const char *> getGCCRegNames() const final { return None; }
+  ArrayRef<const char *> getGCCRegNames() const final { return std::nullopt; }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const final {
-    return None;
+    return std::nullopt;
   }
 
   bool validateAsmConstraint(const char *&Name,
diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 242f9c5..6cf105d 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -1453,7 +1453,7 @@ Optional<unsigned> X86TargetInfo::getCPUCacheLineSize() const {
     // The following currently have unknown cache line sizes (but they are probably all 64):
     // Core
     case CK_None:
-      return None;
+      return std::nullopt;
   }
   llvm_unreachable("Unknown CPU kind");
 }
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
index 62e59c0..1fda9a5 100644
--- a/clang/lib/Basic/Targets/X86.h
+++ b/clang/lib/Basic/Targets/X86.h
@@ -192,7 +192,7 @@ public:
   ArrayRef<const char *> getGCCRegNames() const override;
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   ArrayRef<TargetInfo::AddlRegName> getGCCAddlRegNames() const override;
diff --git a/clang/lib/Basic/Targets/XCore.h b/clang/lib/Basic/Targets/XCore.h
index 25f2058..1919f0d 100644
--- a/clang/lib/Basic/Targets/XCore.h
+++ b/clang/lib/Basic/Targets/XCore.h
@@ -61,7 +61,7 @@ public:
   }
 
   ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
-    return None;
+    return std::nullopt;
   }
 
   bool validateAsmConstraint(const char *&Name,