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[Ada] Fix wrong size for full rep-ed unchecked union
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Tue, 22 Jan 2008 19:16:41 +0100
- Subject: [Ada] Fix wrong size for full rep-ed unchecked union
The compiler gives a null size to the type
type Bit is (Zero, One);
type U (X : Bit := Zero) is record
case X is
when Zero => I: Integer;
when One => F : Float;
end case;
end record;
for U use record
I at 0 range 0 .. 31;
F at 0 range 0 .. 31;
end record;
pragma Unchecked_Union(U);
because of the optimization in components_to_record that reuses the empty
union type and early returns when there are no non-rep components. But
early returning is wrong since the rep-ed components are not laid out yet.
Tested on i586-suse-linux, applied on the mainline.
2008-01-22 Eric Botcazou <ebotcazou@adacore.com>
* decl.c (components_to_record): Do not reuse the empty union type
if there is a representation clause on the record.
* trans.c (addressable_p): Return true for INTEGER_CST.
2008-01-22 Eric Botcazou <ebotcazou@adacore.com>
* gnat.dg/unchecked_union1.adb: New test.
--
Eric Botcazou
Index: decl.c
===================================================================
--- decl.c (revision 131696)
+++ decl.c (working copy)
@@ -6007,11 +6007,15 @@ components_to_record (tree gnu_record_ty
gnu_union_name = concat_id_with_name (gnu_name,
IDENTIFIER_POINTER (gnu_var_name));
- if (!gnu_field_list && TREE_CODE (gnu_record_type) == UNION_TYPE)
+ /* Reuse an enclosing union if all fields are in the variant part
+ and there is no representation clause on the record, to match
+ the layout of C unions. There is an associated check below. */
+ if (!gnu_field_list
+ && TREE_CODE (gnu_record_type) == UNION_TYPE
+ && !TYPE_PACKED (gnu_record_type))
gnu_union_type = gnu_record_type;
else
{
-
gnu_union_type
= make_node (unchecked_union ? UNION_TYPE : QUAL_UNION_TYPE);
@@ -6116,7 +6120,9 @@ components_to_record (tree gnu_record_ty
return. */
if (gnu_union_type == gnu_record_type)
{
- gcc_assert (!gnu_field_list && unchecked_union);
+ gcc_assert (unchecked_union
+ && !gnu_field_list
+ && !gnu_our_rep_list);
return;
}
Index: trans.c
===================================================================
--- trans.c (revision 131696)
+++ trans.c (working copy)
@@ -6070,6 +6070,7 @@ addressable_p (tree gnu_expr)
case INDIRECT_REF:
case CONSTRUCTOR:
case STRING_CST:
+ case INTEGER_CST:
case NULL_EXPR:
case SAVE_EXPR:
case CALL_EXPR:
-- { dg-do run }
procedure Unchecked_Union1 is
type Bit is (Zero, One);
type U (X : Bit := Zero) is record
case X is
when Zero => I: Integer;
when One => F : Float;
end case;
end record;
for U use record
I at 0 range 0 .. 31;
F at 0 range 0 .. 31;
end record;
pragma Unchecked_Union(U);
begin
if U'Object_Size /= 32 then
raise Program_Error;
end if;
end;