[AST][NFC] Pack CXXDefaultInitExpr

Use the newly available space in the bit-fields of Stmt.
This saves one pointer per CXXDefaultInitExpr.

llvm-svn: 347138

clang/include/clang/AST/ExprCXX.h

@@ -1123,26 +1123,23 @@ public:
 /// (C++11 [class.base.init]p8) or in aggregate initialization
 /// (C++1y [dcl.init.aggr]p7).
 class CXXDefaultInitExpr : public Expr {
+  friend class ASTReader;
+  friend class ASTStmtReader;
+
   /// The field whose default is being used.
   FieldDecl *Field;
 
-  /// The location where the default initializer expression was used.
-  SourceLocation Loc;
-
-  CXXDefaultInitExpr(const ASTContext &C, SourceLocation Loc, FieldDecl *Field,
-                     QualType T);
+  CXXDefaultInitExpr(const ASTContext &Ctx, SourceLocation Loc,
+                     FieldDecl *Field, QualType Ty);
 
   CXXDefaultInitExpr(EmptyShell Empty) : Expr(CXXDefaultInitExprClass, Empty) {}
 
 public:
-  friend class ASTReader;
-  friend class ASTStmtReader;
-
   /// \p Field is the non-static data member whose default initializer is used
   /// by this expression.
-  static CXXDefaultInitExpr *Create(const ASTContext &C, SourceLocation Loc,
+  static CXXDefaultInitExpr *Create(const ASTContext &Ctx, SourceLocation Loc,
                                     FieldDecl *Field) {
-    return new (C) CXXDefaultInitExpr(C, Loc, Field, Field->getType());
+    return new (Ctx) CXXDefaultInitExpr(Ctx, Loc, Field, Field->getType());
   }
 
   /// Get the field whose initializer will be used.
@@ -1159,8 +1156,8 @@ public:
     return Field->getInClassInitializer();
   }
 
-  SourceLocation getBeginLoc() const LLVM_READONLY { return Loc; }
-  SourceLocation getEndLoc() const LLVM_READONLY { return Loc; }
+  SourceLocation getBeginLoc() const { return CXXDefaultInitExprBits.Loc; }
+  SourceLocation getEndLoc() const { return CXXDefaultInitExprBits.Loc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == CXXDefaultInitExprClass;

clang/include/clang/AST/Stmt.h

@@ -558,6 +558,16 @@ protected:
     SourceLocation Loc;
   };
 
+  class CXXDefaultInitExprBitfields {
+    friend class ASTStmtReader;
+    friend class CXXDefaultInitExpr;
+
+    unsigned : NumExprBits;
+
+    /// The location where the default initializer expression was used.
+    SourceLocation Loc;
+  };
+
   class TypeTraitExprBitfields {
     friend class ASTStmtReader;
     friend class ASTStmtWriter;
@@ -661,6 +671,7 @@ protected:
     CXXThisExprBitfields CXXThisExprBits;
     CXXThrowExprBitfields CXXThrowExprBits;
     CXXDefaultArgExprBitfields CXXDefaultArgExprBits;
+    CXXDefaultInitExprBitfields CXXDefaultInitExprBits;
     TypeTraitExprBitfields TypeTraitExprBits;
     ExprWithCleanupsBitfields ExprWithCleanupsBits;
 

clang/lib/AST/ExprCXX.cpp

@@ -749,14 +749,15 @@ const IdentifierInfo *UserDefinedLiteral::getUDSuffix() const {
   return cast<FunctionDecl>(getCalleeDecl())->getLiteralIdentifier();
 }
 
-CXXDefaultInitExpr::CXXDefaultInitExpr(const ASTContext &C, SourceLocation Loc,
-                                       FieldDecl *Field, QualType T)
-    : Expr(CXXDefaultInitExprClass, T.getNonLValueExprType(C),
-           T->isLValueReferenceType() ? VK_LValue : T->isRValueReferenceType()
+CXXDefaultInitExpr::CXXDefaultInitExpr(const ASTContext &Ctx, SourceLocation Loc,
+                                       FieldDecl *Field, QualType Ty)
+    : Expr(CXXDefaultInitExprClass, Ty.getNonLValueExprType(Ctx),
+           Ty->isLValueReferenceType() ? VK_LValue : Ty->isRValueReferenceType()
                                                         ? VK_XValue
                                                         : VK_RValue,
            /*FIXME*/ OK_Ordinary, false, false, false, false),
-      Field(Field), Loc(Loc) {
+      Field(Field) {
+  CXXDefaultInitExprBits.Loc = Loc;
   assert(Field->hasInClassInitializer());
 }
 

clang/lib/Serialization/ASTReaderStmt.cpp

@@ -1487,7 +1487,7 @@ void ASTStmtReader::VisitCXXDefaultArgExpr(CXXDefaultArgExpr *E) {
 void ASTStmtReader::VisitCXXDefaultInitExpr(CXXDefaultInitExpr *E) {
   VisitExpr(E);
   E->Field = ReadDeclAs<FieldDecl>();
-  E->Loc = ReadSourceLocation();
+  E->CXXDefaultInitExprBits.Loc = ReadSourceLocation();
 }
 
 void ASTStmtReader::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {