[Bug c++/71694] store-data race with bitfields and tail-padding in C++

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71694

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Dec 16 09:40:03 2016
New Revision: 243738

URL: https://gcc.gnu.org/viewcvs?rev=243738&root=gcc&view=rev
Log:
2016-12-16  Richard Biener  <rguent...@suse.de>

        PR c++/71694
        * langhooks-def.h (lhd_unit_size_without_reusable_padding): Declare.
        (LANG_HOOKS_UNIT_SIZE_WITHOUT_REUSABLE_PADDING): Define.
        (LANG_HOOKS_FOR_TYPES_INITIALIZER): Adjust.
        * langhooks.h (struct lang_hooks_for_types): Add
        unit_size_without_reusable_padding.
        * langhooks.c (lhd_unit_size_without_reusable_padding): New.
        * stor-layout.c (finish_bitfield_representative): Use
        unit_size_without_reusable_padding langhook to decide on the
        last representatives size.

        cp/
        * cp-objcp-common.h (cp_unit_size_without_reusable_padding): Declare.
        (LANG_HOOKS_UNIT_SIZE_WITHOUT_REUSABLE_PADDING): Define.
        * cp-objcp-common.c (cp_unit_size_without_reusable_padding): New.

        * g++.dg/pr71694.C: New testcase.

Added:
    trunk/gcc/testsuite/g++.dg/pr71694.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/cp-objcp-common.c
    trunk/gcc/cp/cp-objcp-common.h
    trunk/gcc/langhooks-def.h
    trunk/gcc/langhooks.c
    trunk/gcc/langhooks.h
    trunk/gcc/stor-layout.c
    trunk/gcc/testsuite/ChangeLog