This gets rid of an old bypass used in the compiler, which would copy
the value set in an Object_Size clause for record types onto Size.
This means that a confirming Object_Size clause can prevent packing,
which is counter-intuitive given that Object_Size is not supposed to
pertain to packing at all.
Tested on x86_64-pc-linux-gnu, committed on trunk
2019-12-18 Eric Botcazou <ebotca...@adacore.com>
gcc/ada/
* layout.adb (Layout_Type): In the case of composite types, do
not copy the Esize onto the RM_Size if the latter is not set.
* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Record_Type>:
Also cap the alignment if an Object_Size clause has been
specified. Pass VAR_DECL in the call to validate_size for the
Esize of a type.
(validate_size): Be prepared to give an error on an Object_Size
clause.--- gcc/ada/gcc-interface/decl.c
+++ gcc/ada/gcc-interface/decl.c
@@ -3054,6 +3054,15 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
if (max_align < BIGGEST_ALIGNMENT)
TYPE_MAX_ALIGN (gnu_type) = max_align;
}
+
+ /* Similarly if an Object_Size clause has been specified. */
+ else if (Known_Esize (gnat_entity))
+ {
+ unsigned int max_size = UI_To_Int (Esize (gnat_entity));
+ unsigned int max_align = max_size & -max_size;
+ if (max_align < BIGGEST_ALIGNMENT)
+ TYPE_MAX_ALIGN (gnu_type) = max_align;
+ }
}
/* If we have a Parent_Subtype, make a field for the parent. If
@@ -4241,11 +4250,15 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, bool definition)
non-constant). */
if (!gnu_size && kind != E_String_Literal_Subtype)
{
- Uint gnat_size = Known_Esize (gnat_entity)
- ? Esize (gnat_entity) : RM_Size (gnat_entity);
- gnu_size
- = validate_size (gnat_size, gnu_type, gnat_entity, TYPE_DECL,
- false, Has_Size_Clause (gnat_entity), NULL, NULL);
+ if (Known_Esize (gnat_entity))
+ gnu_size
+ = validate_size (Esize (gnat_entity), gnu_type, gnat_entity,
+ VAR_DECL, false, false, NULL, NULL);
+ else
+ gnu_size
+ = validate_size (RM_Size (gnat_entity), gnu_type, gnat_entity,
+ TYPE_DECL, false, Has_Size_Clause (gnat_entity),
+ NULL, NULL);
}
/* If a size was specified, see if we can make a new type of that size
@@ -8872,6 +8885,8 @@ validate_size (Uint uint_size, tree gnu_type, Entity_Id gnat_object,
gnat_error_node = Last_Bit (Component_Clause (gnat_object));
else if (Present (Size_Clause (gnat_object)))
gnat_error_node = Expression (Size_Clause (gnat_object));
+ else if (Has_Object_Size_Clause (gnat_object))
+ gnat_error_node = Expression (Object_Size_Clause (gnat_object));
else
gnat_error_node = gnat_object;
--- gcc/ada/layout.adb
+++ gcc/ada/layout.adb
@@ -435,14 +435,6 @@ package body Layout is
end;
end if;
- -- If Esize is set, and RM_Size is not, RM_Size is copied from Esize.
- -- At least for now this seems reasonable, and is in any case needed
- -- for compatibility with old versions of gigi.
-
- if Known_Esize (E) and then Unknown_RM_Size (E) then
- Set_RM_Size (E, Esize (E));
- end if;
-
-- For array base types, set the component size if object size of the
-- component type is known and is a small power of 2 (8, 16, 32, 64),
-- since this is what will always be used, except if a very large
