Revert "[clang] Fix a crash issue that caused by handling of fields with initializers in nested anonymous unions"

This reverts commit 804b103.

Author: yronglin

clang/include/clang/AST/Decl.h

@@ -3219,7 +3219,15 @@ class FieldDecl : public DeclaratorDecl, public Mergeable<FieldDecl> {
 
 public:
   /// Remove the C++11 in-class initializer from this member.
-  void removeInClassInitializer();
+  void removeInClassInitializer() {
+    assert(hasInClassInitializer() && "no initializer to remove");
+    StorageKind = ISK_NoInit;
+    if (BitField) {
+      // Read the bit width before we change the active union member.
+      Expr *ExistingBitWidth = InitAndBitWidth->BitWidth;
+      BitWidth = ExistingBitWidth;
+    }
+  }
 
   /// Determine whether this member captures the variable length array
   /// type.

clang/include/clang/AST/DeclCXX.h

@@ -269,7 +269,6 @@ class CXXRecordDecl : public RecordDecl {
 
   friend void FunctionDecl::setIsPureVirtual(bool);
   friend void TagDecl::startDefinition();
-  friend void FieldDecl::removeInClassInitializer();
 
   /// Values used in DefinitionData fields to represent special members.
   enum SpecialMemberFlags {
@@ -320,9 +319,6 @@ class CXXRecordDecl : public RecordDecl {
     /// The number of virtual base class specifiers in VBases.
     unsigned NumVBases = 0;
 
-    /// The number of C++11 in-class-initializers in this class.
-    unsigned NumInClassInitializers = 0;
-
     /// Base classes of this class.
     ///
     /// FIXME: This is wasted space for a union.
@@ -501,17 +497,6 @@ class CXXRecordDecl : public RecordDecl {
   /// whenever a member is added to this record.
   void addedMember(Decl *D);
 
-  /// Decreasing the number of C++11 in-class-initializers, and update the
-  /// HasInClassInitializer if there is no in-class-initializer in this class.
-  ///
-  /// This routine helps maintain the number of C++11 in-class-initializers.
-  /// The RecordDecl::hasInClassInitializer() needs to be consistent with the
-  /// FieldDecl::hasInClassInitializer(), When calling
-  /// FieldDecl::hasInClassInitializer() to remove the in-class-initializer in
-  /// the field, we need to check whether there are any in-class-initializers in
-  /// this class, and update HasInClassInitializer to the correct value.
-  void removeInClassInitializer();
-
   void markedVirtualFunctionPure();
 
   /// Get the head of our list of friend declarations, possibly

clang/lib/AST/Decl.cpp

@@ -4584,22 +4584,6 @@ void FieldDecl::setInClassInitializer(Expr *NewInit) {
   setLazyInClassInitializer(LazyDeclStmtPtr(NewInit));
 }
 
-void FieldDecl::removeInClassInitializer() {
-  assert(hasInClassInitializer() && "no initializer to remove");
-  StorageKind = ISK_NoInit;
-  if (BitField) {
-    // Read the bit width before we change the active union member.
-    Expr *ExistingBitWidth = InitAndBitWidth->BitWidth;
-    BitWidth = ExistingBitWidth;
-  }
-
-  // The RecordDecl::hasInClassInitializer() needs to be consistent with the
-  // FieldDecl::hasInClassInitializer(). Check the number of C++11
-  // in-class-initializers in the parent class.
-  if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(getParent()))
-    RD->removeInClassInitializer();
-}
-
 void FieldDecl::setLazyInClassInitializer(LazyDeclStmtPtr NewInit) {
   assert(hasInClassInitializer() && !getInClassInitializer());
   if (BitField)

clang/lib/AST/DeclCXX.cpp

@@ -1145,7 +1145,6 @@ void CXXRecordDecl::addedMember(Decl *D) {
         (Field->isAnonymousStructOrUnion() &&
          Field->getType()->getAsCXXRecordDecl()->hasInClassInitializer())) {
       data().HasInClassInitializer = true;
-      data().NumInClassInitializers++;
 
       // C++11 [class]p5:
       //   A default constructor is trivial if [...] no non-static data member
@@ -1442,13 +1441,6 @@ void CXXRecordDecl::addedMember(Decl *D) {
   }
 }
 
-void CXXRecordDecl::removeInClassInitializer() {
-  assert(data().NumInClassInitializers > 0 &&
-         "No member initializer in this class");
-  if (--data().NumInClassInitializers == 0)
-    data().HasInClassInitializer = false;
-}
-
 bool CXXRecordDecl::isLiteral() const {
   const LangOptions &LangOpts = getLangOpts();
   if (!(LangOpts.CPlusPlus20 ? hasConstexprDestructor()

clang/lib/Sema/SemaDeclCXX.cpp

@@ -4088,7 +4088,6 @@ void Sema::ActOnFinishCXXInClassMemberInitializer(Decl *D,
   assert((isa<MSPropertyDecl>(D) || FD->getInClassInitStyle() != ICIS_NoInit) &&
          "must set init style when field is created");
 
-  /// FIXME: We might create an RecoveryExpr for the in-class-initializer.
   if (!InitExpr) {
     D->setInvalidDecl();
     if (FD)

clang/test/SemaCXX/cxx1y-initializer-aggregates.cpp

@@ -115,14 +115,3 @@ namespace nested_union {
   // of Test3, or we should exclude f(Test3) as a candidate.
   static_assert(f({1}) == 2, ""); // expected-error {{call to 'f' is ambiguous}}
 }
-
-// Fix crash issue https://github.com/llvm/llvm-project/issues/112560.
-// Make sure clang compiles the following code without crashing:
-namespace GH112560 {
-union U {
-  int f = ; // expected-error {{expected expression}}
-};
-void foo() {
-  U g{};
-}
-} // namespace GH112560