re PR c++/21166 (g++ gives error on reference to packed structure elements)

.:	PR c++/21166
	* c-decl.c (finish_struct):  Only set DECL_PACKED on a field
	when its natural alignment is > BITS_PER_UNIT.
	* stor-layout.c (finalize_type_size): Revert my patch of 2005-08-08.
	* c-common.c (handle_packed_attribute): Ignore packing on a field
	whose type is naturally char aligned.
cp:
	PR c++/21166
	* class.c (check_field_decls): Only set DECL_PACKED on a field
	when its natural alignment is > BITS_PER_UNIT.

From-SVN: r107599
This commit is contained in:
Nathan Sidwell 2005-11-28 10:34:30 +00:00 committed by Nathan Sidwell
parent bbee4b6468
commit 646c083546
6 changed files with 29 additions and 17 deletions

View File

@ -1,3 +1,12 @@
2005-11-28 Nathan Sidwell <nathan@codesourcery.com>
PR c++/21166
* c-decl.c (finish_struct): Only set DECL_PACKED on a field
when its natural alignment is > BITS_PER_UNIT.
* stor-layout.c (finalize_type_size): Revert my patch of 2005-08-08.
* c-common.c (handle_packed_attribute): Ignore packing on a field
whose type is naturally char aligned.
2005-11-28 Richard Guenther <rguenther@suse.de>
* c-common.c (strict_aliasing_warning): Handle all

View File

@ -4065,17 +4065,23 @@ handle_packed_attribute (tree *node, tree name, tree ARG_UNUSED (args),
struct Foo {
struct Foo const *ptr; // creates a variant w/o packed flag
} __ attribute__((packed)); // packs it now.
*/
} __ attribute__((packed)); // packs it now.
*/
tree probe;
for (probe = *node; probe; probe = TYPE_NEXT_VARIANT (probe))
TYPE_PACKED (probe) = 1;
}
}
else if (TREE_CODE (*node) == FIELD_DECL)
DECL_PACKED (*node) = 1;
{
if (TYPE_ALIGN (TREE_TYPE (*node)) <= BITS_PER_UNIT)
warning (OPT_Wattributes,
"%qE attribute ignored for field of type %qT",
name, TREE_TYPE (*node));
else
DECL_PACKED (*node) = 1;
}
/* We can't set DECL_PACKED for a VAR_DECL, because the bit is
used for DECL_REGISTER. It wouldn't mean anything anyway.
We can't set DECL_PACKED on the type of a TYPE_DECL, because

View File

@ -5326,7 +5326,9 @@ finish_struct (tree t, tree fieldlist, tree attributes)
for (x = fieldlist; x; x = TREE_CHAIN (x))
{
DECL_CONTEXT (x) = t;
DECL_PACKED (x) |= TYPE_PACKED (t);
if (TYPE_PACKED (t) && TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
DECL_PACKED (x) = 1;
/* If any field is const, the structure type is pseudo-const. */
if (TREE_READONLY (x))

View File

@ -1,3 +1,9 @@
2005-11-28 Nathan Sidwell <nathan@codesourcery.com>
PR c++/21166
* class.c (check_field_decls): Only set DECL_PACKED on a field
when its natural alignment is > BITS_PER_UNIT.
2005-11-27 Volker Reichelt <reichelt@igpm.rwth-aachen.de>
PR c++/24979

View File

@ -2801,7 +2801,7 @@ check_field_decls (tree t, tree *access_decls,
(0,
"ignoring packed attribute on unpacked non-POD field %q+#D",
x);
else
else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
DECL_PACKED (x) = 1;
}

View File

@ -1495,8 +1495,6 @@ finalize_type_size (tree type)
void
finish_record_layout (record_layout_info rli, int free_p)
{
tree field;
/* Compute the final size. */
finalize_record_size (rli);
@ -1506,15 +1504,6 @@ finish_record_layout (record_layout_info rli, int free_p)
/* Perform any last tweaks to the TYPE_SIZE, etc. */
finalize_type_size (rli->t);
/* We might be able to clear DECL_PACKED on any members that happen
to be suitably aligned (not forgetting the alignment of the type
itself). */
for (field = TYPE_FIELDS (rli->t); field; field = TREE_CHAIN (field))
if (TREE_CODE (field) == FIELD_DECL && DECL_PACKED (field)
&& DECL_OFFSET_ALIGN (field) >= TYPE_ALIGN (TREE_TYPE (field))
&& TYPE_ALIGN (rli->t) >= TYPE_ALIGN (TREE_TYPE (field)))
DECL_PACKED (field) = 0;
/* Lay out any static members. This is done now because their type
may use the record's type. */
while (rli->pending_statics)