Re: Fix gnu versioned namespace mode 00/03

[Iain Sandoe <idsandoe@googlemail.com>]

> On 13 May 2024, at 06:06, François Dumont <frs.dumont@gmail.com> wrote:
> 
> 
> On 07/05/2024 18:15, Iain Sandoe wrote:
>> Hi François
>> 
>>> On 4 May 2024, at 22:11, François Dumont <frs.dumont@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.
>>> 
>>> 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).
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66146

Also, AFAICT, any nested once_call is a problem (not just exceptions).

>>  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.
> 
> The reason I'm proposing to integrate this patch this early in gcc 15 stage is to have time to integrate any other library fix/optimization that could make use of it. I already have 1 on my side for the hashtable implementation

Ah, then I think we are aiming for the same thing.

> . I hope your once_call fix also have time to be ready for gcc 15, no ?

Yes; if we put it behind the versioned namespace - there are (I think) several proposed solutions to that specific issue.

thanks
Iain

> 
> François