On 13/05/2024 10:34, Jonathan Wakely wrote:
On Mon, 13 May 2024, 07:30 Iain Sandoe, <idsan...@googlemail.com> wrote:
> On 13 May 2024, at 06:06, François Dumont <frs.dum...@gmail.com>
wrote:
>
>
> On 07/05/2024 18:15, Iain Sandoe wrote:
>> Hi François
>>
>>> On 4 May 2024, at 22:11, François Dumont
<frs.dum...@gmail.com> wrote:
>>>
>>> Here is the list of patches to restore gnu versioned namespace
mode.
>>>
>>> 1/3: Bump gnu version namespace
>>>
>>> This is important to be done first so that once build of gnu
versioned namespace is fixed there is no chance to have another
build of '__8' version with a different abi than last successful
'__8' build.
The versioned namespace build is not expected to be ABI compatible
though, so nobody should be expecting compatibility with previous
builds. Especially not on the gcc-15 trunk, a week or two after
entering stage 1!
Ok, I really thought that we needed to preserve ABI for a given version,
'__8' at the moment.
>>>
>>> 2/3: Fix build using cxx11 abi for versioned namespace
>>>
>>> 3/3: Proposal to default to "new" abi when dual abi is
disabled and accept any default-libstdcxx-abi either dual abi is
enabled or not.
>>>
>>> All testsuite run for following configs:
>>>
>>> - dual abi
>>>
>>> - gcc4-compatible only abi
>>>
>>> - new only abi
>>>
>>> - versioned namespace abi
>> At the risk of delaying this (a bit) - I think we should also
consider items like once_call that have broken impls.
> Do you have any pointer to this once_call problem, sorry I'm not
aware about it (apart from your messages).
(although this mentions one specific target, it applies more widely).
I've removed the "on ppc64le" part from the summary.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66146
Thanks for the ref, I'll have a look but I fear that I won't be of any
help here.
Also, AFAICT, any nested once_call is a problem (not just exceptions).
Could you update the bug with that info please?
>> in the current library - and at least get proposed
replacements available behind the versioned namespace; rather than
using up a namespace version with the current broken code.
>
> I'm not proposing to fix all library bugs on all platforms with
this patch, just fix the versioned namespace mode.
Sorry, I was not intending to suggest that (although perhaps my
comments read that way).
I was trying to suggest that, in the case where we have proposed
fixes that are blocked because they are ABI breaks, that those
could be put behind the versioned namspace (it was not an
intention to suggest that such additions should be part of this
patch series).
> As to do so I also need to adopt cxx11 abi in versioned mode it
already justify a bump of version.
I see - it’s just a bit strange that we are bumping a version for
a mode that does not currently work; however, i guess someone
might have deployed it even so.
It does work though, doesn't it?
It's known to fail on powerpc64 due to conflicts with the ieee128
stuff, but it should work elsewhere.
It doesn't work with --with-default-libstdcxx-abi=cxx11 but that's
just a "this doesn't work and isn't supported" limitation.
The point of the patch series is to change it so the versioned
namespace always uses the cxx11 ABI, which does seem worth bumping the
version (even though the versioned namespace is explicitly not a
stable ABI and not backwards compatible).
So I just need to wait for proper review, right ?
This is what I plan to do on this subject for the moment.
