Re: [PATCH] sso-string@gnu-versioned-namespace [PR83077]

[Jonathan Wakely <jwakely@redhat.com>]

On Sun, 13 Aug 2023 at 14:27, François Dumont via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> Here is the fixed patch tested in all 3 modes:
>
> - _GLIBCXX_USE_DUAL_ABI
>
> - !_GLIBCXX_USE_DUAL_ABI && !_GLIBCXX_USE_CXX11_ABI
>
> - !_GLIBCXX_USE_DUAL_ABI && _GLIBCXX_USE_CXX11_ABI
>
> I don't know what you have in mind for the change below but I wanted to
> let you know that I tried to put COW std::basic_string into a nested
> __cow namespace when _GLIBCXX_USE_CXX11_ABI. But it had more impact on
> string-inst.cc so I preferred the macro substitution approach.

I was thinking of implementing the necessary special members functions
of __cow_string directly, so they are ABI compatible with the COW
std::basic_string but don't actually reuse the code. That would mean
we don't need to compile and instantiate the whole COW string just to
use a few members from it. But that can be done later, the macro
approach seems OK for now.

>
> There are some test failing when !_GLIBCXX_USE_CXX11_ABI that are
> unrelated with my changes. I'll propose fixes in coming days.

Which tests? I run the entire testsuite with
-D_GLIBCXX_USE_CXX11_ABI=0 several times per day and I'm not seeing
failures.

I'll review the patch ASAP, thanks for working on it.