[clang][NFC] Reorder CXXCtorInitializer members

[njames93]

Summary

Swapping the order of Init and MemberOrEllipsisLocation removes 8 bytes (20%) of padding on 64bit builds.

[aaron.ballman]

LGTM, good catch!

clang/include/clang/AST/DeclCXX.h

 /// \endcode
 class CXXCtorInitializer final {
   /// Either the base class name/delegating constructor type (stored as
   /// a TypeSourceInfo*), an normal field (FieldDecl), or an anonymous field
   /// (IndirectFieldDecl*) being initialized.
   llvm::PointerUnion<TypeSourceInfo *, FieldDecl *, IndirectFieldDecl *>
       Initializee;
 
+  /// The argument used to initialize the base or member, which may
+  /// end up constructing an object (when multiple arguments are involved).
+  Stmt *Init;
+
   /// The source location for the field name or, for a base initializer
   /// pack expansion, the location of the ellipsis.
   ///
   /// In the case of a delegating
   /// constructor, it will still include the type's source location as the
   /// Initializee points to the CXXConstructorDecl (to allow loop detection).
   SourceLocation MemberOrEllipsisLocation;
 
-  /// The argument used to initialize the base or member, which may
-  /// end up constructing an object (when multiple arguments are involved).
-  Stmt *Init;
-
   /// Location of the left paren of the ctor-initializer.
   SourceLocation LParenLoc;
 
   /// Location of the right paren of the ctor-initializer.
   SourceLocation RParenLoc;
 
   /// If the initializee is a type, whether that type makes this
   /// a delegating initialization.

clang/lib/AST/DeclCXX.cpp

return P->isLambda() && getDeclName().isIdentifier() &&
          getName() == getLambdaStaticInvokerName();
 }
 
 CXXCtorInitializer::CXXCtorInitializer(ASTContext &Context,
                                        TypeSourceInfo *TInfo, bool IsVirtual,
                                        SourceLocation L, Expr *Init,
                                        SourceLocation R,
                                        SourceLocation EllipsisLoc)
-    : Initializee(TInfo), MemberOrEllipsisLocation(EllipsisLoc), Init(Init),
+    : Initializee(TInfo), Init(Init), MemberOrEllipsisLocation(EllipsisLoc),
       LParenLoc(L), RParenLoc(R), IsDelegating(false), IsVirtual(IsVirtual),
       IsWritten(false), SourceOrder(0) {}
 
-CXXCtorInitializer::CXXCtorInitializer(ASTContext &Context,
-                                       FieldDecl *Member,
+CXXCtorInitializer::CXXCtorInitializer(ASTContext &Context, FieldDecl *Member,
                                        SourceLocation MemberLoc,
                                        SourceLocation L, Expr *Init,
                                        SourceLocation R)
-    : Initializee(Member), MemberOrEllipsisLocation(MemberLoc), Init(Init),
+    : Initializee(Member), Init(Init), MemberOrEllipsisLocation(MemberLoc),
       LParenLoc(L), RParenLoc(R), IsDelegating(false), IsVirtual(false),
       IsWritten(false), SourceOrder(0) {}
 
 CXXCtorInitializer::CXXCtorInitializer(ASTContext &Context,
                                        IndirectFieldDecl *Member,
                                        SourceLocation MemberLoc,
                                        SourceLocation L, Expr *Init,
                                        SourceLocation R)
-    : Initializee(Member), MemberOrEllipsisLocation(MemberLoc), Init(Init),
+    : Initializee(Member), Init(Init), MemberOrEllipsisLocation(MemberLoc),
       LParenLoc(L), RParenLoc(R), IsDelegating(false), IsVirtual(false),
       IsWritten(false), SourceOrder(0) {}
 
 CXXCtorInitializer::CXXCtorInitializer(ASTContext &Context,
                                        TypeSourceInfo *TInfo,
                                        SourceLocation L, Expr *Init,
                                        SourceLocation R)
     : Initializee(TInfo), Init(Init), LParenLoc(L), RParenLoc(R),