Re: git: bc9e19dce0ab - main - Fix buildworld with gcc 12 after llvm-19 import

On 29 Oct 2024, at 18:09, John Baldwin <jhb@FreeBSD.org> wrote:
> On 10/28/24 16:12, Dimitry Andric wrote:
>> On 28 Oct 2024, at 20:56, John Baldwin <jhb@freebsd.org> wrote:
>>> 
>>> On 10/25/24 12:08, Dimitry Andric wrote:
>>>> The branch main has been updated by dim:
>>>> URL: https://cgit.FreeBSD.org/src/commit/?id=bc9e19dce0abee80750e6fa04aaf979873bfe0d2
>>>> commit bc9e19dce0abee80750e6fa04aaf979873bfe0d2
>>>> Author:     Dimitry Andric <dim@FreeBSD.org>
>>>> AuthorDate: 2024-10-25 16:07:59 +0000
>>>> Commit:     Dimitry Andric <dim@FreeBSD.org>
>>>> CommitDate: 2024-10-25 16:08:32 +0000
>>>>     Fix buildworld with gcc 12 after llvm-19 import
>>>>          Unfortunately gcc 12's is not yet capable of compiling all of libc++
>>>>     19's C++23 code, which results in errors similar to:
>>>>            /usr/src/freebsd/src/contrib/llvm-project/libcxx/include/__algorithm/ranges_contains.h:41:3: error: 'static constexpr bool std::__1::ranges::__contains::__fn::operator()(_Iter, _Sent, const _Type&, _Proj)' must be a non-static member function
>>>>          41 |   operator()(_Iter __first, _Sent __last, const _Type& __value, _Proj __proj = {}) {
>>>>             |   ^~~~~~~~
>>>>       /usr/src/freebsd/src/contrib/llvm-project/libcxx/include/__algorithm/ranges_contains.h:48:3: error: 'static constexpr bool std::__1::ranges::__contains::__fn::operator()(_Range&&, const _Type&, _Proj)' must be a non-static member function
>>>>          48 |   operator()(_Range&& __range, const _Type& __value, _Proj __proj = {}) {
>>>>             |   ^~~~~~~~
>>>>          Until we can get rid of gcc 12, work around this by making it compile
>>>>     libc++ in C++20 mode instead.
>>>>          NOTE: The resulting libc++ library will not be C++23 compatible! Please
>>>>     try to avoid shipping it, and use gcc 13 instead, if you must use gcc.
>>>>          PR:             280562
>>>>     MFC after:      3 days
>>> 
>>> In this case I think we probably should drop support for GCC 12 for main.  Just let me
>>> know when you are thinking of merging libcxx 19 to stable branches so I can ensure they
>>> build with GCC 13/14 and get our CI jobs updated before then.
>> It depends a bit on how many ports still need to be fixed, and of course when 13.5 and 14.2 are done. After those I will probably do the merges.
>> That said, is gcc 13 good for all arches we want to support? In the past we still kept a few old gcc versions alive because they were the only one that could build for $OBSOLETE_ARCH.
> 
> I am only aware that GCC 12+ can build amd64 world + GENERIC currently.  I believe
> aarch64 is close.  i386 is also pretty close (but I care less about it).   riscv64
> needs a libatomic since GCC doesn't inline atomics as much as clang.  I haven't
> really tried powerpc much.

GCC 13 did finally fix that for RISC-V.

Jess