              _fromUnsafeMutablePointer: UnsafeMutableRawPointer(
                Builtin.addressof(&self.header)))
   }
-
-  @usableFromInline // c-abi
-  internal var gpRegistersUsed = 0
-  @usableFromInline // c-abi
-  internal var fpRegistersUsed = 0
-
-  @usableFromInline // c-abi
-  final  // Property must be final since it is used by Builtin.addressof.
-  internal var header = Header()
-  @usableFromInline // c-abi
-  internal var storage: ContiguousArray<Int>
 }
 
 #else
 
 /// An object that can manage the lifetime of storage backing a
 /// `CVaListPointer`.
-@_fixed_layout // FIXME(sil-serialize-all)
-@_fixed_layout // c-abi
+@_fixed_layout
 @usableFromInline // c-abi
 final internal class _VaListBuilder {
 

    @usableFromInline // c-abi
    internal var reg_save_area: UnsafeMutablePointer<Int>?
  }

  @inlinable // c-abi
  internal init() {


/// An object that can manage the lifetime of storage backing a
/// `CVaListPointer`.
@_fixed_layout
@usableFromInline // c-abi
final internal class _VaListBuilder {
  @_fixed_layout // c-abi
  @usableFromInline
  internal struct Header {
