StructLayoutEntry::decl
If a SgInitializedName, the field represented by this entry If a SgClassDeclaration, the anonymous union represented by this entry If a SgBaseClass, the base class represented by this entry If NULL, this entry is padding
If a SgInitializedName, the field represented by this entry If a SgClassDeclaration, the anonymous union represented by this entry If a SgBaseClass, the base class represented by this entry If NULL, this entry is padding