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

[Christophe LYON]

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 ;-)