* c-common.c (warn_abi): New variable.
* c-common.h (warn_abi): Likewise.
* c-opts.c (COMMAND_LINE_OPTIONS): Add -Wabi.
(c_common_decode_option): Handle it.
* doc/invoke.texi:P Document -Wabi.
* class.c (layout_virtual_bases): Warn about bugs in G++ that
result in incorrect object layouts.
(layout_class_type): Likewise.
* testsuite/g++.dg/abi/bitfield5.C: New test.
* testsuite/g++.dg/abi/vbase10.C: Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@56618
138bc75d-0d04-0410-961f-
82ee72b054a4