[clang][NFC] Refactor CXXNewExpr::InitializationStyle (#71322)

This patch converts `CXXNewExpr::InitializationStyle` into a scoped enum at namespace scope. It also affirms the status quo by adding a new enumerator to represent implicit initializer.

clang-tools-extra/clang-tidy/modernize/MakeSmartPtrCheck.cpp

@@ -323,7 +323,8 @@ bool MakeSmartPtrCheck::replaceNew(DiagnosticBuilder &Diag,
     return false;
   };
   switch (New->getInitializationStyle()) {
-  case CXXNewExpr::NoInit: {
+  case CXXNewInitializationStyle::None:
+  case CXXNewInitializationStyle::Implicit: {
     if (ArraySizeExpr.empty()) {
       Diag << FixItHint::CreateRemoval(SourceRange(NewStart, NewEnd));
     } else {
@@ -334,7 +335,7 @@ bool MakeSmartPtrCheck::replaceNew(DiagnosticBuilder &Diag,
     }
     break;
   }
-  case CXXNewExpr::CallInit: {
+  case CXXNewInitializationStyle::Call: {
     // FIXME: Add fixes for constructors with parameters that can be created
     // with a C++11 braced-init-list (e.g. std::vector, std::map).
     // Unlike ordinal cases, braced list can not be deduced in
@@ -371,7 +372,7 @@ bool MakeSmartPtrCheck::replaceNew(DiagnosticBuilder &Diag,
     }
     break;
   }
-  case CXXNewExpr::ListInit: {
+  case CXXNewInitializationStyle::List: {
     // Range of the substring that we do not want to remove.
     SourceRange InitRange;
     if (const auto *NewConstruct = New->getConstructExpr()) {

clang/include/clang/AST/ExprCXX.h

@@ -2206,6 +2206,20 @@ class CXXScalarValueInitExpr : public Expr {
   }
 };
 
+enum class CXXNewInitializationStyle {
+  /// New-expression has no initializer as written.
+  None,
+
+  /// New-expression has no written initializer, but has an implicit one.
+  Implicit,
+
+  /// New-expression has a C++98 paren-delimited initializer.
+  Call,
+
+  /// New-expression has a C++11 list-initializer.
+  List
+};
+
 /// Represents a new-expression for memory allocation and constructor
 /// calls, e.g: "new CXXNewExpr(foo)".
 class CXXNewExpr final
@@ -2259,25 +2273,12 @@ class CXXNewExpr final
     return isParenTypeId();
   }
 
-public:
-  enum InitializationStyle {
-    /// New-expression has no initializer as written.
-    NoInit,
-
-    /// New-expression has a C++98 paren-delimited initializer.
-    CallInit,
-
-    /// New-expression has a C++11 list-initializer.
-    ListInit
-  };
-
-private:
   /// Build a c++ new expression.
   CXXNewExpr(bool IsGlobalNew, FunctionDecl *OperatorNew,
              FunctionDecl *OperatorDelete, bool ShouldPassAlignment,
              bool UsualArrayDeleteWantsSize, ArrayRef<Expr *> PlacementArgs,
              SourceRange TypeIdParens, std::optional<Expr *> ArraySize,
-             InitializationStyle InitializationStyle, Expr *Initializer,
+             CXXNewInitializationStyle InitializationStyle, Expr *Initializer,
              QualType Ty, TypeSourceInfo *AllocatedTypeInfo, SourceRange Range,
              SourceRange DirectInitRange);
 
@@ -2292,7 +2293,7 @@ class CXXNewExpr final
          FunctionDecl *OperatorDelete, bool ShouldPassAlignment,
          bool UsualArrayDeleteWantsSize, ArrayRef<Expr *> PlacementArgs,
          SourceRange TypeIdParens, std::optional<Expr *> ArraySize,
-         InitializationStyle InitializationStyle, Expr *Initializer,
+         CXXNewInitializationStyle InitializationStyle, Expr *Initializer,
          QualType Ty, TypeSourceInfo *AllocatedTypeInfo, SourceRange Range,
          SourceRange DirectInitRange);
 
@@ -2388,15 +2389,20 @@ class CXXNewExpr final
 
   /// Whether this new-expression has any initializer at all.
   bool hasInitializer() const {
-    return CXXNewExprBits.StoredInitializationStyle > 0;
+    switch (getInitializationStyle()) {
+    case CXXNewInitializationStyle::None:
+      return false;
+    case CXXNewInitializationStyle::Implicit:
+    case CXXNewInitializationStyle::Call:
+    case CXXNewInitializationStyle::List:
+      return true;
+    }
   }
 
   /// The kind of initializer this new-expression has.
-  InitializationStyle getInitializationStyle() const {
-    if (CXXNewExprBits.StoredInitializationStyle == 0)
-      return NoInit;
-    return static_cast<InitializationStyle>(
-        CXXNewExprBits.StoredInitializationStyle - 1);
+  CXXNewInitializationStyle getInitializationStyle() const {
+    return static_cast<CXXNewInitializationStyle>(
+        CXXNewExprBits.StoredInitializationStyle);
   }
 
   /// The initializer of this new-expression.

clang/lib/AST/ExprCXX.cpp

@@ -184,7 +184,7 @@ CXXNewExpr::CXXNewExpr(bool IsGlobalNew, FunctionDecl *OperatorNew,
                        bool UsualArrayDeleteWantsSize,
                        ArrayRef<Expr *> PlacementArgs, SourceRange TypeIdParens,
                        std::optional<Expr *> ArraySize,
-                       InitializationStyle InitializationStyle,
+                       CXXNewInitializationStyle InitializationStyle,
                        Expr *Initializer, QualType Ty,
                        TypeSourceInfo *AllocatedTypeInfo, SourceRange Range,
                        SourceRange DirectInitRange)
@@ -193,15 +193,17 @@ CXXNewExpr::CXXNewExpr(bool IsGlobalNew, FunctionDecl *OperatorNew,
       AllocatedTypeInfo(AllocatedTypeInfo), Range(Range),
       DirectInitRange(DirectInitRange) {
 
-  assert((Initializer != nullptr || InitializationStyle == NoInit) &&
+  assert((Initializer != nullptr ||
+          InitializationStyle == CXXNewInitializationStyle::None ||
+          InitializationStyle == CXXNewInitializationStyle::Implicit) &&
          "Only NoInit can have no initializer!");
 
   CXXNewExprBits.IsGlobalNew = IsGlobalNew;
   CXXNewExprBits.IsArray = ArraySize.has_value();
   CXXNewExprBits.ShouldPassAlignment = ShouldPassAlignment;
   CXXNewExprBits.UsualArrayDeleteWantsSize = UsualArrayDeleteWantsSize;
   CXXNewExprBits.StoredInitializationStyle =
-      Initializer ? InitializationStyle + 1 : 0;
+      llvm::to_underlying(InitializationStyle);
   bool IsParenTypeId = TypeIdParens.isValid();
   CXXNewExprBits.IsParenTypeId = IsParenTypeId;
   CXXNewExprBits.NumPlacementArgs = PlacementArgs.size();
@@ -217,10 +219,10 @@ CXXNewExpr::CXXNewExpr(bool IsGlobalNew, FunctionDecl *OperatorNew,
     getTrailingObjects<SourceRange>()[0] = TypeIdParens;
 
   switch (getInitializationStyle()) {
-  case CallInit:
+  case CXXNewInitializationStyle::Call:
     this->Range.setEnd(DirectInitRange.getEnd());
     break;
-  case ListInit:
+  case CXXNewInitializationStyle::List:
     this->Range.setEnd(getInitializer()->getSourceRange().getEnd());
     break;
   default:
@@ -240,15 +242,14 @@ CXXNewExpr::CXXNewExpr(EmptyShell Empty, bool IsArray,
   CXXNewExprBits.IsParenTypeId = IsParenTypeId;
 }
 
-CXXNewExpr *
-CXXNewExpr::Create(const ASTContext &Ctx, bool IsGlobalNew,
-                   FunctionDecl *OperatorNew, FunctionDecl *OperatorDelete,
-                   bool ShouldPassAlignment, bool UsualArrayDeleteWantsSize,
-                   ArrayRef<Expr *> PlacementArgs, SourceRange TypeIdParens,
-                   std::optional<Expr *> ArraySize,
-                   InitializationStyle InitializationStyle, Expr *Initializer,
-                   QualType Ty, TypeSourceInfo *AllocatedTypeInfo,
-                   SourceRange Range, SourceRange DirectInitRange) {
+CXXNewExpr *CXXNewExpr::Create(
+    const ASTContext &Ctx, bool IsGlobalNew, FunctionDecl *OperatorNew,
+    FunctionDecl *OperatorDelete, bool ShouldPassAlignment,
+    bool UsualArrayDeleteWantsSize, ArrayRef<Expr *> PlacementArgs,
+    SourceRange TypeIdParens, std::optional<Expr *> ArraySize,
+    CXXNewInitializationStyle InitializationStyle, Expr *Initializer,
+    QualType Ty, TypeSourceInfo *AllocatedTypeInfo, SourceRange Range,
+    SourceRange DirectInitRange) {
   bool IsArray = ArraySize.has_value();
   bool HasInit = Initializer != nullptr;
   unsigned NumPlacementArgs = PlacementArgs.size();

clang/lib/AST/ItaniumMangle.cpp

@@ -4826,7 +4826,7 @@ void CXXNameMangler::mangleExpression(const Expr *E, unsigned Arity,
     Out << '_';
     mangleType(New->getAllocatedType());
     if (New->hasInitializer()) {
-      if (New->getInitializationStyle() == CXXNewExpr::ListInit)
+      if (New->getInitializationStyle() == CXXNewInitializationStyle::List)
         Out << "il";
       else
         Out << "pi";
@@ -4840,7 +4840,8 @@ void CXXNameMangler::mangleExpression(const Expr *E, unsigned Arity,
       } else if (const ParenListExpr *PLE = dyn_cast<ParenListExpr>(Init)) {
         for (unsigned i = 0, e = PLE->getNumExprs(); i != e; ++i)
           mangleExpression(PLE->getExpr(i));
-      } else if (New->getInitializationStyle() == CXXNewExpr::ListInit &&
+      } else if (New->getInitializationStyle() ==
+                     CXXNewInitializationStyle::List &&
                  isa<InitListExpr>(Init)) {
         // Only take InitListExprs apart for list-initialization.
         mangleInitListElements(cast<InitListExpr>(Init));

clang/lib/AST/JSONNodeDumper.cpp

@@ -1351,9 +1351,15 @@ void JSONNodeDumper::VisitCXXNewExpr(const CXXNewExpr *NE) {
   attributeOnlyIfTrue("isArray", NE->isArray());
   attributeOnlyIfTrue("isPlacement", NE->getNumPlacementArgs() != 0);
   switch (NE->getInitializationStyle()) {
-  case CXXNewExpr::NoInit: break;
-  case CXXNewExpr::CallInit: JOS.attribute("initStyle", "call"); break;
-  case CXXNewExpr::ListInit: JOS.attribute("initStyle", "list"); break;
+  case CXXNewInitializationStyle::None:
+  case CXXNewInitializationStyle::Implicit:
+    break;
+  case CXXNewInitializationStyle::Call:
+    JOS.attribute("initStyle", "call");
+    break;
+  case CXXNewInitializationStyle::List:
+    JOS.attribute("initStyle", "list");
+    break;
   }
   if (const FunctionDecl *FD = NE->getOperatorNew())
     JOS.attribute("operatorNewDecl", createBareDeclRef(FD));

clang/lib/AST/StmtPrinter.cpp

@@ -2298,9 +2298,10 @@ void StmtPrinter::VisitCXXNewExpr(CXXNewExpr *E) {
   if (E->isParenTypeId())
     OS << ")";
 
-  CXXNewExpr::InitializationStyle InitStyle = E->getInitializationStyle();
-  if (InitStyle != CXXNewExpr::NoInit) {
-    bool Bare = InitStyle == CXXNewExpr::CallInit &&
+  CXXNewInitializationStyle InitStyle = E->getInitializationStyle();
+  if (InitStyle != CXXNewInitializationStyle::None &&
+      InitStyle != CXXNewInitializationStyle::Implicit) {
+    bool Bare = InitStyle == CXXNewInitializationStyle::Call &&
                 !isa<ParenListExpr>(E->getInitializer());
     if (Bare)
       OS << "(";

clang/lib/AST/StmtProfile.cpp

@@ -2096,7 +2096,7 @@ void StmtProfiler::VisitCXXNewExpr(const CXXNewExpr *S) {
   ID.AddInteger(S->getNumPlacementArgs());
   ID.AddBoolean(S->isGlobalNew());
   ID.AddBoolean(S->isParenTypeId());
-  ID.AddInteger(S->getInitializationStyle());
+  ID.AddInteger(llvm::to_underlying(S->getInitializationStyle()));
 }
 
 void

clang/lib/Sema/SemaExprCXX.cpp

@@ -1946,7 +1946,7 @@ Sema::ActOnCXXNew(SourceLocation StartLoc, bool UseGlobal,
                      Initializer);
 }
 
-static bool isLegalArrayNewInitializer(CXXNewExpr::InitializationStyle Style,
+static bool isLegalArrayNewInitializer(CXXNewInitializationStyle Style,
                                        Expr *Init) {
   if (!Init)
     return true;
@@ -1957,7 +1957,7 @@ static bool isLegalArrayNewInitializer(CXXNewExpr::InitializationStyle Style,
   else if (CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init))
     return !CCE->isListInitialization() &&
            CCE->getConstructor()->isDefaultConstructor();
-  else if (Style == CXXNewExpr::ListInit) {
+  else if (Style == CXXNewInitializationStyle::List) {
     assert(isa<InitListExpr>(Init) &&
            "Shouldn't create list CXXConstructExprs for arrays.");
     return true;
@@ -2008,44 +2008,49 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   SourceRange TypeRange = AllocTypeInfo->getTypeLoc().getSourceRange();
   SourceLocation StartLoc = Range.getBegin();
 
-  CXXNewExpr::InitializationStyle initStyle;
+  CXXNewInitializationStyle InitStyle;
   if (DirectInitRange.isValid()) {
     assert(Initializer && "Have parens but no initializer.");
-    initStyle = CXXNewExpr::CallInit;
+    InitStyle = CXXNewInitializationStyle::Call;
   } else if (Initializer && isa<InitListExpr>(Initializer))
-    initStyle = CXXNewExpr::ListInit;
+    InitStyle = CXXNewInitializationStyle::List;
   else {
     assert((!Initializer || isa<ImplicitValueInitExpr>(Initializer) ||
             isa<CXXConstructExpr>(Initializer)) &&
            "Initializer expression that cannot have been implicitly created.");
-    initStyle = CXXNewExpr::NoInit;
+    InitStyle = CXXNewInitializationStyle::None;
   }
 
   MultiExprArg Exprs(&Initializer, Initializer ? 1 : 0);
   if (ParenListExpr *List = dyn_cast_or_null<ParenListExpr>(Initializer)) {
-    assert(initStyle == CXXNewExpr::CallInit && "paren init for non-call init");
+    assert(InitStyle == CXXNewInitializationStyle::Call &&
+           "paren init for non-call init");
     Exprs = MultiExprArg(List->getExprs(), List->getNumExprs());
   }
 
   // C++11 [expr.new]p15:
   //   A new-expression that creates an object of type T initializes that
   //   object as follows:
-  InitializationKind Kind
-      //     - If the new-initializer is omitted, the object is default-
-      //       initialized (8.5); if no initialization is performed,
-      //       the object has indeterminate value
-      = initStyle == CXXNewExpr::NoInit
-            ? InitializationKind::CreateDefault(TypeRange.getBegin())
-            //     - Otherwise, the new-initializer is interpreted according to
-            //     the
-            //       initialization rules of 8.5 for direct-initialization.
-            : initStyle == CXXNewExpr::ListInit
-                  ? InitializationKind::CreateDirectList(
-                        TypeRange.getBegin(), Initializer->getBeginLoc(),
-                        Initializer->getEndLoc())
-                  : InitializationKind::CreateDirect(TypeRange.getBegin(),
-                                                     DirectInitRange.getBegin(),
-                                                     DirectInitRange.getEnd());
+  InitializationKind Kind = [&] {
+    switch (InitStyle) {
+    //     - If the new-initializer is omitted, the object is default-
+    //       initialized (8.5); if no initialization is performed,
+    //       the object has indeterminate value
+    case CXXNewInitializationStyle::None:
+    case CXXNewInitializationStyle::Implicit:
+      return InitializationKind::CreateDefault(TypeRange.getBegin());
+    //     - Otherwise, the new-initializer is interpreted according to the
+    //       initialization rules of 8.5 for direct-initialization.
+    case CXXNewInitializationStyle::Call:
+      return InitializationKind::CreateDirect(TypeRange.getBegin(),
+                                              DirectInitRange.getBegin(),
+                                              DirectInitRange.getEnd());
+    case CXXNewInitializationStyle::List:
+      return InitializationKind::CreateDirectList(TypeRange.getBegin(),
+                                                  Initializer->getBeginLoc(),
+                                                  Initializer->getEndLoc());
+    }
+  }();
 
   // C++11 [dcl.spec.auto]p6. Deduce the type which 'auto' stands in for.
   auto *Deduced = AllocType->getContainedDeducedType();
@@ -2066,13 +2071,14 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
       return ExprError();
   } else if (Deduced && !Deduced->isDeduced()) {
     MultiExprArg Inits = Exprs;
-    bool Braced = (initStyle == CXXNewExpr::ListInit);
+    bool Braced = (InitStyle == CXXNewInitializationStyle::List);
     if (Braced) {
       auto *ILE = cast<InitListExpr>(Exprs[0]);
       Inits = MultiExprArg(ILE->getInits(), ILE->getNumInits());
     }
 
-    if (initStyle == CXXNewExpr::NoInit || Inits.empty())
+    if (InitStyle == CXXNewInitializationStyle::None ||
+        InitStyle == CXXNewInitializationStyle::Implicit || Inits.empty())
       return ExprError(Diag(StartLoc, diag::err_auto_new_requires_ctor_arg)
                        << AllocType << TypeRange);
     if (Inits.size() > 1) {
@@ -2396,7 +2402,7 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
   // Array 'new' can't have any initializers except empty parentheses.
   // Initializer lists are also allowed, in C++11. Rely on the parser for the
   // dialect distinction.
-  if (ArraySize && !isLegalArrayNewInitializer(initStyle, Initializer)) {
+  if (ArraySize && !isLegalArrayNewInitializer(InitStyle, Initializer)) {
     SourceRange InitRange(Exprs.front()->getBeginLoc(),
                           Exprs.back()->getEndLoc());
     Diag(StartLoc, diag::err_new_array_init_args) << InitRange;
@@ -2468,7 +2474,7 @@ ExprResult Sema::BuildCXXNew(SourceRange Range, bool UseGlobal,
 
   return CXXNewExpr::Create(Context, UseGlobal, OperatorNew, OperatorDelete,
                             PassAlignment, UsualArrayDeleteWantsSize,
-                            PlacementArgs, TypeIdParens, ArraySize, initStyle,
+                            PlacementArgs, TypeIdParens, ArraySize, InitStyle,
                             Initializer, ResultType, AllocTypeInfo, Range,
                             DirectInitRange);
 }