Re: [PATCH] qemu-user: fix build with LLVM lld 10

[Alex Bennée]

Daniel P. Berrangé <address@hidden> writes:

> On Fri, Mar 27, 2020 at 03:44:47PM +0000, Alex Bennée wrote:
>> 
>> Roger Pau Monné <address@hidden> writes:
>> 
>> > On Fri, Mar 27, 2020 at 11:28:04AM +0000, Alex Bennée wrote:
>> >> 
>> >> Roger Pau Monné <address@hidden> writes:
>> >> 
>> >> > On Thu, Mar 26, 2020 at 09:56:38AM -0700, Richard Henderson wrote:
>> >> >> On 3/26/20 6:43 AM, Roger Pau Monne wrote:
>> >> >> > lld 10.0.0 introduced a new linker option --image-base equivalent to
>> >> >> > the GNU -Ttext-segment one, hence use it when available.
>> >> >> > 
>> >> >> > This fixes the build of QEMU on systems using lld 10 or greater.
>> >> >> > 
>> >> >> > Signed-off-by: Dimitry Andric <address@hidden>
>> >> >> > Signed-off-by: Roger Pau Monné <address@hidden>
>> >> >> > ---
>> >> >> > Cc: Laurent Vivier <address@hidden>
>> >> >> > Cc: Richard Henderson <address@hidden>
>> >> >> > Cc: "Philippe Mathieu-Daudé" <address@hidden>
>> >> >> > Cc: Paolo Bonzini <address@hidden>
>> >> >> > Cc: "Daniel P. Berrangé" <address@hidden>
>> >> >> > ---
>> >> >> 
>> >> >> The Plan is still to drop this whole section of code.
>> >> >> 
>> >> >> However, it's still blocked on getting the x86_64 vsyscall patches 
>> >> >> upstream.
>> >> >
>> >> > While this doesn't materialize, could it be possible to get this patch
>> >> > accepted?
>> >> >
>> >> > This is currently blocking the build of QEMU on FreeBSD HEAD, which
>> >> > has already switched to LLVM 10.0.0.
>> >> 
>> >> I think the vsyscall patch has just been merged, however way I don't
>> >> think targeting HEAD of a OS release during the rc phase is appropriate.
>> >
>> > I'm not sure I understand what you mean. If QEMU doesn't build on
>> > FreeBSD HEAD it won't build on the next release. Also the LLVM
>> > toolchain used is not a development version AFAIK, but the actual
>> > 10.0.0 release, which QEMU should aim to support?
>> 
>> QEMU's supported build platforms are based on what is currently shipping
>> as stable versions:
>> 
>>   https://www.qemu.org/docs/master/system/build-platforms.html
>
> FWIW, when I wrote that my intention was *not* to exclude the bleeding
> edge distro development branches.
>
> Obviously we can break on those distros at any time as they're moving
> targets, but IMHO we should treat bugs as we would for any other
> released distros and aim to fix them promptly when bugs occurr.

Sure - I think there are now patches incoming from Richard to delete the
linker code which should meet the criteria for an RC fix, especially if
they solve the LLVM 10.0 problem as well. 

-- 
Alex Bennée