The reason is that the automatic alignment promotion is not yet performed
in the case where the nominal subtype is of variable size.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* gcc-interface/decl.c (promote_object_alignment): Add GNU_SIZE
parameter and use it for the size of the object if not null.
(gnat_to_gnu_entity) <E_Variable>: Perform the automatic alignment
promotion for objects whose nominal subtype is of variable size.
(gnat_to_gnu_field): Adjust call to promote_object_alignment.diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -239,7 +239,7 @@ static tree validate_size (Uint, tree, Entity_Id, enum tree_code, bool, bool,
const char *, const char *);
static void set_rm_size (Uint, tree, Entity_Id);
static unsigned int validate_alignment (Uint, Entity_Id, unsigned int);
-static unsigned int promote_object_alignment (tree, Entity_Id);
+static unsigned int promote_object_alignment (tree, tree, Entity_Id);
static void check_ok_for_atomic_type (tree, Entity_Id, bool);
static tree create_field_decl_from (tree, tree, tree, tree, tree,
vec<subst_pair>);
@@ -897,7 +897,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
or a reference to another object, and the size of its type is a
constant, set the alignment to the smallest one which is not
smaller than the size, with an appropriate cap. */
- if (!gnu_size && align == 0
+ if (!Known_Esize (gnat_entity)
+ && !Known_Alignment (gnat_entity)
&& (Is_Full_Access (gnat_entity)
|| (!Optimize_Alignment_Space (gnat_entity)
&& kind != E_Exception
@@ -908,8 +909,8 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
&& !imported_p
&& No (gnat_renamed_obj)
&& No (Address_Clause (gnat_entity))))
- && TREE_CODE (TYPE_SIZE (gnu_type)) == INTEGER_CST)
- align = promote_object_alignment (gnu_type, gnat_entity);
+ && (TREE_CODE (TYPE_SIZE (gnu_type)) == INTEGER_CST || gnu_size))
+ align = promote_object_alignment (gnu_type, gnu_size, gnat_entity);
/* If the object is set to have atomic components, find the component
type and validate it.
@@ -7322,7 +7323,7 @@ gnat_to_gnu_field (Entity_Id gnat_field, tree gnu_record_type, int packed,
if (Is_Full_Access (gnat_field))
{
const unsigned int align
- = promote_object_alignment (gnu_field_type, gnat_field);
+ = promote_object_alignment (gnu_field_type, NULL_TREE, gnat_field);
if (align > 0)
gnu_field_type
= maybe_pad_type (gnu_field_type, NULL_TREE, align, gnat_field,
@@ -9393,11 +9394,11 @@ validate_alignment (Uint alignment, Entity_Id gnat_entity, unsigned int align)
return align;
}
-/* Promote the alignment of GNU_TYPE corresponding to GNAT_ENTITY. Return
- a positive value on success or zero on failure. */
+/* Promote the alignment of GNU_TYPE for an object with GNU_SIZE corresponding
+ to GNAT_ENTITY. Return a positive value on success or zero on failure. */
static unsigned int
-promote_object_alignment (tree gnu_type, Entity_Id gnat_entity)
+promote_object_alignment (tree gnu_type, tree gnu_size, Entity_Id gnat_entity)
{
unsigned int align, size_cap, align_cap;
@@ -9418,14 +9419,17 @@ promote_object_alignment (tree gnu_type, Entity_Id gnat_entity)
align_cap = get_mode_alignment (ptr_mode);
}
+ if (!gnu_size)
+ gnu_size = TYPE_SIZE (gnu_type);
+
/* Do the promotion within the above limits. */
- if (!tree_fits_uhwi_p (TYPE_SIZE (gnu_type))
- || compare_tree_int (TYPE_SIZE (gnu_type), size_cap) > 0)
+ if (!tree_fits_uhwi_p (gnu_size)
+ || compare_tree_int (gnu_size, size_cap) > 0)
align = 0;
- else if (compare_tree_int (TYPE_SIZE (gnu_type), align_cap) > 0)
+ else if (compare_tree_int (gnu_size, align_cap) > 0)
align = align_cap;
else
- align = ceil_pow2 (tree_to_uhwi (TYPE_SIZE (gnu_type)));
+ align = ceil_pow2 (tree_to_uhwi (gnu_size));
/* But make sure not to under-align the object. */
if (align <= TYPE_ALIGN (gnu_type))
