Normally pragma Optimize_Alignment (Space) forces an alignment of 1
for any packed record, but we can't do that for a variable length
record, since we can't implement that case, so ignore the pragma
in this case with a warning.
The following test program shows the patch in action:
1. pragma optimize_alignment (space);
2. procedure testalign is
3. subtype Continuous_Values is float;
4. type Continuous_Values_Map is
5. array ( integer range <> ) of Continuous_Values;
6.
7. type my_record (s : integer) is record
|
>>> Optimize_Alignment has no effect for "my_record"
>>> pragma is ignored for variable length record
8. x : continuous_values_map (1 .. s);
9. end record;
10. pragma pack (my_record);
11.
12. type my_record2 (s : integer) is record
13. x : continuous_values_map (1 .. 1000);
14. end record;
15. pragma pack (my_record2);
16.
17. begin
18. null;
19. end;
Tested on x86_64-pc-linux-gnu, committed on trunk
2012-10-29 Robert Dewar <de...@adacore.com>
* layout.adb (Set_Composite_Alignment): Ignore pragma
Optimize_Alignment (Space) for packed variable length records.
Index: layout.adb
===================================================================
--- layout.adb (revision 192918)
+++ layout.adb (working copy)
@@ -2882,7 +2882,12 @@
and then Is_Packed (E)
and then not Is_Atomic (E)
then
- Align := 1;
+ if not Size_Known_At_Compile_Time (E) then
+ Error_Msg_N ("Optimize_Alignment has no effect for &", E);
+ Error_Msg_N ("\pragma is ignored for variable length record?", E);
+ else
+ Align := 1;
+ end if;
-- Not a record, or not packed
