[OE-core] [RFC][PATCH] gcc-runtime.inc: force libstdc++ to always use gcc4 compatible ABI

[Khem Raj]

> On Jan 26, 2016, at 12:10 AM, Andre McCurdy <armccurdy at gmail.com> wrote:
> 
> Experimental hack, not expected to be merged.
> 
> Without this, the http://www.cplusplus.com/reference/string/string/append/
> example fails to build with -std=c++11 and it's not clear why (it's as if we
> build a version of libstdc++ which supports only the old ABI but with headers
> which try to use the new ABI when compiled with -std=c++11 ?). As a workaround,
> force libstdc++ to provide, and default to using, the old ABI in all cases.
> 
> See also:
> 
>  https://gcc.gnu.org/onlinedocs/libstdc++/manual/configure.html
>  https://mail.gnome.org/archives/gtkmm-list/2015-June/msg00026.html
>  https://wiki.debian.org/GCC5
> 
> Signed-off-by: Andre McCurdy <armccurdy at gmail.com>
> ---
> meta/recipes-devtools/gcc/gcc-runtime.inc | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
> 
> diff --git a/meta/recipes-devtools/gcc/gcc-runtime.inc b/meta/recipes-devtools/gcc/gcc-runtime.inc
> index f20d298..3a476cd 100644
> --- a/meta/recipes-devtools/gcc/gcc-runtime.inc
> +++ b/meta/recipes-devtools/gcc/gcc-runtime.inc
> @@ -10,6 +10,19 @@ EXTRA_OECONF_PATHS = "\
> 
> EXTRA_OECONF_append_linuxstdbase = " --enable-clocale=gnu"
> 
> +# gcc-runtime.inc: force libstdc++ to always use gcc4 compatible ABI
> +# Experimental hack. Without this, the http://www.cplusplus.com/reference/string/string/append/
> +# example fails to build with -std=c++11 and it's not clear why (it's as if we
> +# build a version of libstdc++ which supports only the old ABI but with headers
> +# which try to use the new ABI when compiled with -std=c++11 ?). As a workaround,
> +# force libstdc++ to provide, and default to using, the old ABI in all cases.
> +# See also:
> +# https://gcc.gnu.org/onlinedocs/libstdc++/manual/configure.html
> +# https://mail.gnome.org/archives/gtkmm-list/2015-June/msg00026.html
> +# https://wiki.debian.org/GCC5
> +#
> +EXTRA_OECONF_append = " --disable-libstdcxx-dual-abi --with-default-libstdcxx-abi=gcc4-compatible”

This change while makes it work compatible to older libstdc++ ABI, we should make the defaults to be
forward looking. I would rather keep --with-default-libstdcxx-abi=c++11 since gcc6 will switch to newer
c++ std as default. If we revert like you suggest, we will be up for more work in gcc6 time.

please define _GLIBCXX_USE_CXX11_ABI=0 for your app, where you see the problem.

> +

> RUNTIMETARGET = "libssp libstdc++-v3 libgomp libatomic \
>     ${@bb.utils.contains_any('FORTRAN', [',fortran',',f77'], 'libquadmath', '', d)} \
> "
> --
> 1.9.1
> 
> --
> _______________________________________________
> Openembedded-core mailing list
> Openembedded-core at lists.openembedded.org
> http://lists.openembedded.org/mailman/listinfo/openembedded-core

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 204 bytes
Desc: Message signed with OpenPGP using GPGMail
URL: <http://lists.openembedded.org/pipermail/openembedded-core/attachments/20160126/bed2ded6/attachment-0002.sig>