[PATCH v3] libstdc++: Improve std::lock algorithm

[Christophe LYON]

On 23/06/2021 12:11, Jonathan Wakely wrote:
> On Wed, 23 Jun 2021 at 10:43, Christophe LYON wrote:
>>
>> On 23/06/2021 11:17, Jonathan Wakely via Libstdc++ wrote:
>>> On Wed, 23 Jun 2021 at 08:21, Christophe Lyon wrote:
>>>> This patch causes GCC build failures for bare-metal targets
>>>> (aarch64-elf, arm-eabi). For instance on arm-eabi, I'm seeing:
>>>>
>>>> In file included from
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/arm-none-eabi/libstdc++-v3/include/future:38,
>>>>                    from
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/include/precompiled/stdc++.h:105:
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/arm-none-eabi/libstdc++-v3/include/mutex:
>>>> In function 'int std::__detail::__try_lock_impl(_Lockable&)':
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/arm-none-eabi/libstdc++-v3/include/mutex:522:53:
>>>> error: expected primary-expression before ',' token
>>>>     522 |         if (unique_lock<_Lockable> __lock{__lockable, try_to_lock})
>>>>         |                                                     ^
>>>> In file included from
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/arm-none-eabi/libstdc++-v3/include/future:38,
>>>>                    from
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/include/precompiled/stdc++.h:105:
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/arm-none-eabi/libstdc++-v3/include/mutex:
>>>> In function 'int std::__detail::__try_lock_impl(_Lockable&)':
>>>> /tmp/1229695_7.tmpdir/aci-gcc-fsf/builds/gcc-fsf-gccsrc/obj-arm-none-eabi/gcc3/arm-none-eabi/libstdc++-v3/include/mutex:522:53:
>>>> error: expected primary-expression before ',' token
>>>>     522 |         if (unique_lock<_Lockable> __lock{__lockable, try_to_lock})
>>>>         |                                                     ^
>>>> make[4]: *** [Makefile:1862:
>>>> arm-none-eabi/bits/stdc++.h.gch/O2ggnu++0x.gch] Error 1
>>> Sigh, __lockable is a macro in newlib:
>>>
>>> newlib/libc/include/sys/cdefs.h:#define __lockable
>>> __lock_annotate(lockable)
>>>
>>> I'll change the name.
>> Thanks (sorry for being back ;-)
> Fixed with this patch, tested x86_64 and pushed to trunk.

Thanks for the prompt fix, I confirm it's OK again on my side.


Christophe