[clang] 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

1 files changed, 26 insertions, 24 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index a637b92..e9ad412 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -176,7 +176,7 @@ static llvm::Optional<bool> normalizeSimpleFlag(OptSpecifier Opt,
                                                 DiagnosticsEngine &Diags) {
   if (Args.hasArg(Opt))
     return true;
-  return None;
+  return std::nullopt;
 }
 
 static Optional<bool> normalizeSimpleNegativeFlag(OptSpecifier Opt, unsigned,
@@ -184,7 +184,7 @@ static Optional<bool> normalizeSimpleNegativeFlag(OptSpecifier Opt, unsigned,
                                                   DiagnosticsEngine &) {
   if (Args.hasArg(Opt))
     return false;
-  return None;
+  return std::nullopt;
 }
 
 /// The tblgen-erated code passes in a fifth parameter of an arbitrary type, but
@@ -209,7 +209,7 @@ static auto makeFlagToValueNormalizer(T Value) {
                  DiagnosticsEngine &) -> Optional<T> {
     if (Args.hasArg(Opt))
       return Value;
-    return None;
+    return std::nullopt;
   };
 }
 
@@ -227,7 +227,7 @@ static auto makeBooleanOptionNormalizer(bool Value, bool OtherValue,
     if (const Arg *A = Args.getLastArg(Opt, OtherOpt)) {
       return A->getOption().matches(Opt) ? Value : OtherValue;
     }
-    return None;
+    return std::nullopt;
   };
 }
 
@@ -276,7 +276,7 @@ findValueTableByName(const SimpleEnumValueTable &Table, StringRef Name) {
     if (Name == Table.Table[I].Name)
       return Table.Table[I];
 
-  return None;
+  return std::nullopt;
 }
 
 static Optional<SimpleEnumValue>
@@ -285,7 +285,7 @@ findValueTableByValue(const SimpleEnumValueTable &Table, unsigned Value) {
     if (Value == Table.Table[I].Value)
       return Table.Table[I];
 
-  return None;
+  return std::nullopt;
 }
 
 static llvm::Optional<unsigned> normalizeSimpleEnum(OptSpecifier Opt,
@@ -297,7 +297,7 @@ static llvm::Optional<unsigned> normalizeSimpleEnum(OptSpecifier Opt,
 
   auto *Arg = Args.getLastArg(Opt);
   if (!Arg)
-    return None;
+    return std::nullopt;
 
   StringRef ArgValue = Arg->getValue();
   if (auto MaybeEnumVal = findValueTableByName(Table, ArgValue))
@@ -305,7 +305,7 @@ static llvm::Optional<unsigned> normalizeSimpleEnum(OptSpecifier Opt,
 
   Diags.Report(diag::err_drv_invalid_value)
       << Arg->getAsString(Args) << ArgValue;
-  return None;
+  return std::nullopt;
 }
 
 static void denormalizeSimpleEnumImpl(SmallVectorImpl<const char *> &Args,
@@ -339,7 +339,7 @@ static Optional<std::string> normalizeString(OptSpecifier Opt, int TableIndex,
                                              DiagnosticsEngine &Diags) {
   auto *Arg = Args.getLastArg(Opt);
   if (!Arg)
-    return None;
+    return std::nullopt;
   return std::string(Arg->getValue());
 }
 
@@ -349,12 +349,12 @@ static Optional<IntTy> normalizeStringIntegral(OptSpecifier Opt, int,
                                                DiagnosticsEngine &Diags) {
   auto *Arg = Args.getLastArg(Opt);
   if (!Arg)
-    return None;
+    return std::nullopt;
   IntTy Res;
   if (StringRef(Arg->getValue()).getAsInteger(0, Res)) {
     Diags.Report(diag::err_drv_invalid_int_value)
         << Arg->getAsString(Args) << Arg->getValue();
-    return None;
+    return std::nullopt;
   }
   return Res;
 }
@@ -402,7 +402,7 @@ static Optional<std::string> normalizeTriple(OptSpecifier Opt, int TableIndex,
                                              DiagnosticsEngine &Diags) {
   auto *Arg = Args.getLastArg(Opt);
   if (!Arg)
-    return None;
+    return std::nullopt;
   return llvm::Triple::normalize(Arg->getValue());
 }
 
@@ -1064,11 +1064,12 @@ static void initOption(AnalyzerOptions::ConfigTable &Config,
 static void initOption(AnalyzerOptions::ConfigTable &Config,
                        DiagnosticsEngine *Diags,
                        bool &OptionField, StringRef Name, bool DefaultVal) {
-  auto PossiblyInvalidVal = llvm::StringSwitch<Optional<bool>>(
-                 getStringOption(Config, Name, (DefaultVal ? "true" : "false")))
-      .Case("true", true)
-      .Case("false", false)
-      .Default(None);
+  auto PossiblyInvalidVal =
+      llvm::StringSwitch<Optional<bool>>(
+          getStringOption(Config, Name, (DefaultVal ? "true" : "false")))
+          .Case("true", true)
+          .Case("false", false)
+          .Default(std::nullopt);
 
   if (!PossiblyInvalidVal) {
     if (Diags)
@@ -1382,10 +1383,10 @@ void CompilerInvocation::GenerateCodeGenArgs(
     DebugInfoVal = "unused-types";
     break;
   case codegenoptions::NoDebugInfo: // default value
-    DebugInfoVal = None;
+    DebugInfoVal = std::nullopt;
     break;
   case codegenoptions::LocTrackingOnly: // implied value
-    DebugInfoVal = None;
+    DebugInfoVal = std::nullopt;
     break;
   }
   if (DebugInfoVal)
@@ -2504,7 +2505,7 @@ static Optional<frontend::ActionKind> getFrontendAction(OptSpecifier &Opt) {
     if (ActionOpt.second == Opt.getID())
       return ActionOpt.first;
 
-  return None;
+  return std::nullopt;
 }
 
 /// Maps frontend action to command line option.
@@ -2514,7 +2515,7 @@ getProgramActionOpt(frontend::ActionKind ProgramAction) {
     if (ActionOpt.first == ProgramAction)
       return OptSpecifier(ActionOpt.second);
 
-  return None;
+  return std::nullopt;
 }
 
 static void GenerateFrontendArgs(const FrontendOptions &Opts,
@@ -2996,8 +2997,8 @@ static void GenerateHeaderSearchArgs(HeaderSearchOptions &Opts,
   auto End = Opts.UserEntries.end();
 
   // Add -I..., -F..., and -index-header-map options in order.
-  for (; It < End &&
-         Matches(*It, {frontend::IndexHeaderMap, frontend::Angled}, None, true);
+  for (; It < End && Matches(*It, {frontend::IndexHeaderMap, frontend::Angled},
+                             std::nullopt, true);
        ++It) {
     OptSpecifier Opt = [It, Matches]() {
       if (Matches(*It, frontend::IndexHeaderMap, true, true))
@@ -3035,7 +3036,8 @@ static void GenerateHeaderSearchArgs(HeaderSearchOptions &Opts,
     GenerateArg(Args, OPT_idirafter, It->Path, SA);
   for (; It < End && Matches(*It, {frontend::Quoted}, false, true); ++It)
     GenerateArg(Args, OPT_iquote, It->Path, SA);
-  for (; It < End && Matches(*It, {frontend::System}, false, None); ++It)
+  for (; It < End && Matches(*It, {frontend::System}, false, std::nullopt);
+       ++It)
     GenerateArg(Args, It->IgnoreSysRoot ? OPT_isystem : OPT_iwithsysroot,
                 It->Path, SA);
   for (; It < End && Matches(*It, {frontend::System}, true, true); ++It)