Improved based on reviews

Author: YexuanXiao

clang/include/clang/AST/ASTContext.h

@@ -278,8 +278,8 @@ class ASTContext : public RefCountedBase<ASTContext> {
       ArrayParameterTypes;
 
   /// Store the unique Type corresponding to each Kind.
-  mutable std::array<Type *, llvm::to_underlying(
-                                 PredefinedSugarType::Kind::NumElements)>
+  mutable std::array<Type *,
+                     llvm::to_underlying(PredefinedSugarType::Kind::Last) + 1>
       PredefinedSugarTypes{};
 
   /// The set of nested name specifiers.

clang/include/clang/AST/Type.h

@@ -2269,7 +2269,7 @@ class alignas(TypeAlignment) Type : public ExtQualsTypeCommonBase {
     PtrdiffT,
 
     // Indicates how many items the enum has.
-    NumElements
+    Last = PtrdiffT
   };
 
   class PresefinedSugarTypeBitfields {

clang/lib/AST/ASTContext.cpp

@@ -2595,7 +2595,6 @@ TypeInfo ASTContext::getTypeInfoImpl(const Type *T) const {
       Align = static_cast<unsigned>(Width);
     }
   }
-
   break;
 
   case Type::PredefinedSugar:
@@ -5224,8 +5223,6 @@ QualType
 ASTContext::getPredefinedSugarType(PredefinedSugarType::Kind KD) const {
   using Kind = PredefinedSugarType::Kind;
 
-  assert(KD != Kind::NumElements);
-
   if (auto *Target = PredefinedSugarTypes[llvm::to_underlying(KD)];
       Target != nullptr)
     return QualType(Target, 0);
@@ -5243,7 +5240,6 @@ ASTContext::getPredefinedSugarType(PredefinedSugarType::Kind KD) const {
       return Ctx.getFromTargetType(Ctx.Target->getSignedSizeType());
     case Kind::PtrdiffT:
       return Ctx.getFromTargetType(Ctx.Target->getPtrDiffType(LangAS::Default));
-    case Kind::NumElements:;
     }
     llvm_unreachable("unexpected kind");
   };

clang/lib/AST/FormatString.cpp

@@ -322,17 +322,12 @@ bool clang::analyze_format_string::ParseUTF8InvalidSpecifier(
 
 static bool namedTypeToLengthModifierKind(ASTContext &Ctx, QualType QT,
                                           LengthModifier::Kind &K) {
-  for (/**/; const auto *TT = QT->getAs<TypedefType>();
-       QT = TT->getDecl()->getUnderlyingType()) {
+  if (!Ctx.getLangOpts().C99 && !Ctx.getLangOpts().CPlusPlus)
+    return false;
+  for (/**/; const auto *TT = QT->getAs<TypedefType>(); QT = TT->desugar()) {
     const auto *TD = TT->getDecl();
     const auto *DC = TT->getDecl()->getDeclContext();
-    bool RC = false;
-    if (Ctx.getLangOpts().C99) {
-      RC = DC->isTranslationUnit();
-    } else if (Ctx.getLangOpts().CPlusPlus) {
-      RC = DC->isTranslationUnit() || DC->isStdNamespace();
-    }
-    if (RC) {
+    if (DC->isTranslationUnit() || DC->isStdNamespace()) {
       StringRef Name = TD->getIdentifier()->getName();
       if (Name == "size_t") {
         K = LengthModifier::AsSizeT;
@@ -362,9 +357,8 @@ static bool namedTypeToLengthModifierKind(ASTContext &Ctx, QualType QT,
     case Kind::PtrdiffT:
       K = LengthModifier::AsPtrDiff;
       return true;
-    case Kind::NumElements:
-      llvm_unreachable("unexpected kind");
     }
+    llvm_unreachable("unexpected kind");
   }
   return false;
 }

clang/lib/AST/Type.cpp

@@ -5622,7 +5622,6 @@ StringRef PredefinedSugarType::getName(Kind KD) {
     return "__signed_size_t";
   case Kind::PtrdiffT:
     return "__ptrdiff_t";
-  case Kind::NumElements:;
   }
   llvm_unreachable("unexpected kind");
 }

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -721,8 +721,7 @@ static bool matchesStlAllocatorFn(const Decl *D, const ASTContext &Ctx) {
       (MD->getNumParams() != 1 && MD->getNumParams() != 2))
     return false;
 
-  if (MD->parameters()[0]->getType().getCanonicalType() !=
-      Ctx.getCanonicalSizeType())
+  if (!Ctx.hasSameType(MD->parameters()[0]->getType(), Ctx.getSizeType()))
     return false;
 
   if (MD->getNumParams() == 2) {

clang/lib/Serialization/ASTWriter.cpp

@@ -692,7 +692,6 @@ void TypeLocWriter::VisitAtomicTypeLoc(AtomicTypeLoc TL) {
 void TypeLocWriter::VisitPipeTypeLoc(PipeTypeLoc TL) {
   addSourceLocation(TL.getKWLoc());
 }
-
 void TypeLocWriter::VisitBitIntTypeLoc(clang::BitIntTypeLoc TL) {
   addSourceLocation(TL.getNameLoc());
 }