The compiler would wrongly reject an alignment clause larger than 8 on
the component type of an array of scalars, which is valid albeit
pathological.
Tested on x86_64-pc-linux-gnu, committed on trunk
2019-07-03 Eric Botcazou <ebotca...@adacore.com>
gcc/ada/
* layout.adb (Layout_Type): Do not set the component size of an
array with a scalar component if the component type is
overaligned.
gcc/testsuite/
* gnat.dg/alignment14.adb: New testcase.--- gcc/ada/layout.adb
+++ gcc/ada/layout.adb
@@ -443,9 +443,12 @@ package body Layout is
Set_RM_Size (E, Esize (E));
end if;
- -- For array base types, set component size if object size of the
+ -- 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.
+ -- since this is what will always be used, except if a very large
+ -- alignment was specified and so Adjust_Esize_For_Alignment gave up
+ -- because, in this case, the object size is not a multiple of the
+ -- alignment and, therefore, cannot be the component size.
if Ekind (E) = E_Array_Type and then Unknown_Component_Size (E) then
declare
@@ -458,6 +461,9 @@ package body Layout is
if Present (CT)
and then Is_Scalar_Type (CT)
and then Known_Static_Esize (CT)
+ and then not (Known_Alignment (CT)
+ and then Alignment_In_Bits (CT) >
+ Standard_Long_Long_Integer_Size)
then
declare
S : constant Uint := Esize (CT);
--- /dev/null
new file mode 100644
+++ gcc/testsuite/gnat.dg/alignment14.adb
@@ -0,0 +1,17 @@
+-- { dg-do compile }
+
+procedure Alignment14 is
+
+ type My_Int1 is new Integer;
+ for My_Int1'Alignment use 8;
+
+ type Arr1 is array (1 .. 2) of My_Int1;
+
+ type My_Int2 is new Integer;
+ for My_Int2'Alignment use 16;
+
+ type Arr2 is array (1 .. 2) of My_Int2;
+
+begin
+ null;
+end Alignment14;
