From 2cd36c22d3d16e24f342829a989ac35f2f442656 Mon Sep 17 00:00:00 2001 From: Adam Nemet Date: Fri, 23 Jan 2009 06:29:54 +0000 Subject: c-decl.c (finish_struct): Move code to set DECL_PACKED after DECL_BIT_FIELD is alreay known. * c-decl.c (finish_struct): Move code to set DECL_PACKED after DECL_BIT_FIELD is alreay known. Also inherit packed for bitfields regardless of their type. * c-common.c (handle_packed_attribute): Don't ignore packed on bitfields. * c.opt (Wpacked-bitfield-compat): New warning option. * stor-layout.c (place_field): Warn if offset of a field changed. * doc/extend.texi (packed): Mention the ABI change. * doc/invoke.texi (-Wpacked-bitfield-compat): Document. (Warning Options): Add it to the list. cp/ * class.c (check_field_decls): Also inherit packed for bitfields regardless of their type. testsuite/ * gcc.dg/bitfld-15.c, gcc.dg/bitfld-16.c, gcc.dg/bitfld-17.c,gcc.dg/bitfld-18.c: New tests. * g++.dg/ext/bitfield2.C, g++.dg/ext/bitfield3.C, g++.dg/ext/bitfield4.C, g++.dg/ext/bitfield5.C: New tests. From-SVN: r143584 --- gcc/stor-layout.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) (limited to 'gcc/stor-layout.c') diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c index 0e7caa5..bf896db 100644 --- a/gcc/stor-layout.c +++ b/gcc/stor-layout.c @@ -937,7 +937,9 @@ place_field (record_layout_info rli, tree field) && TREE_CODE (field) == FIELD_DECL && type != error_mark_node && DECL_BIT_FIELD (field) - && ! DECL_PACKED (field) + && (! DECL_PACKED (field) + /* Enter for these packed fields only to issue a warning. */ + || TYPE_ALIGN (type) <= BITS_PER_UNIT) && maximum_field_alignment == 0 && ! integer_zerop (DECL_SIZE (field)) && host_integerp (DECL_SIZE (field), 1) @@ -958,9 +960,21 @@ place_field (record_layout_info rli, tree field) /* A bit field may not span more units of alignment of its type than its type itself. Advance to next boundary if necessary. */ if (excess_unit_span (offset, bit_offset, field_size, type_align, type)) - rli->bitpos = round_up (rli->bitpos, type_align); + { + if (DECL_PACKED (field)) + { + if (warn_packed_bitfield_compat) + inform + (input_location, + "Offset of packed bit-field %qD has changed in GCC 4.4", + field); + } + else + rli->bitpos = round_up (rli->bitpos, type_align); + } - TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type); + if (! DECL_PACKED (field)) + TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type); } #endif -- cgit v1.1