@@ -3059,7 +3059,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
Present (gnat_field);
gnat_field = Next_Entity (gnat_field))
if ((Ekind (gnat_field) == E_Component
- || Ekind (gnat_field) == E_Discriminant)
+ || (Ekind (gnat_field) == E_Discriminant
+ && !is_unchecked_union))
&& No (Component_Clause (gnat_field)))
{
all_rep = false;
@@ -7874,8 +7875,7 @@ typedef struct vinfo
DEBUG_INFO is true if we need to write debug information about the type.
- MAYBE_UNUSED is true if this type may be unused in the end; this doesn't
- mean that its contents may be unused as well, only the container itself.
+ IN_VARIANT is true if the componennt list is that of a variant.
FIRST_FREE_POS, if nonzero, is the first (lowest) free field position in
the outer record type down to this variant level. It is nonzero only if
@@ -7890,7 +7890,7 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
tree gnu_field_list, tree gnu_record_type, int packed,
bool definition, bool cancel_alignment, bool all_rep,
bool unchecked_union, bool artificial, bool debug_info,
- bool maybe_unused, tree first_free_pos,
+ bool in_variant, tree first_free_pos,
tree *p_gnu_rep_list)
{
const bool needs_xv_encodings
@@ -8075,15 +8075,21 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
= TYPE_SIZE_UNIT (gnu_record_type);
}
- /* Add the fields into the record type for the variant. Note that
- we aren't sure to really use it at this point, see below. */
+ /* Add the fields into the record type for the variant but note that
+ we aren't sure to really use it at this point, see below. In the
+ case of an unchecked union, we force the fields with a rep clause
+ present in a nested variant to be moved to the outermost variant,
+ so as to flatten the rep-ed layout as much as possible, the reason
+ being that we cannot do any flattening when a subtype statically
+ selects a variant later on, for example for an aggregate. */
has_rep
= components_to_record (Component_List (variant), gnat_record_type,
NULL_TREE, gnu_variant_type, packed,
definition, !all_rep_and_size, all_rep,
unchecked_union, true, needs_xv_encodings,
true, this_first_free_pos,
- all_rep || this_first_free_pos
+ (all_rep || this_first_free_pos)
+ && !(in_variant && unchecked_union)
? NULL : &gnu_rep_list);
/* Translate the qualifier and annotate the GNAT node. */
@@ -8206,9 +8212,9 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
finish_record_type (gnu_union_type, nreverse (gnu_variant_list),
all_rep_and_size ? 1 : 0, needs_xv_encodings);
- /* If GNU_UNION_TYPE is our record type, it means we must have an
- Unchecked_Union with no fields. Verify that and, if so, just
- return. */
+ /* If GNU_UNION_TYPE is our record type, this means that we must have
+ an Unchecked_Union whose fields are all in the variant part. Now
+ verify that and, if so, just return. */
if (gnu_union_type == gnu_record_type)
{
gcc_assert (unchecked_union
@@ -8275,7 +8281,6 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
= (Convention (gnat_record_type) == Convention_Ada
&& Warn_On_Questionable_Layout
&& !(No_Reordering (gnat_record_type) && GNAT_Mode));
- const bool in_variant = (p_gnu_rep_list != NULL);
tree gnu_zero_list = NULL_TREE;
tree gnu_self_list = NULL_TREE;
tree gnu_var_list = NULL_TREE;
@@ -8640,7 +8645,7 @@ components_to_record (Node_Id gnat_component_list, Entity_Id gnat_record_type,
TYPE_ARTIFICIAL (gnu_record_type) = artificial;
finish_record_type (gnu_record_type, gnu_field_list, layout_with_rep ? 1 : 0,
- debug_info && !maybe_unused);
+ debug_info && !in_variant);
/* Chain the fields with zero size at the beginning of the field list. */
if (gnu_zero_list)