[CAULDRON] Topics for the Toolchain and Linux kernel BoF

[Sam James]

Xi Ruoyao <xry111@xry111.site> writes:

> On Thu, 2024-09-12 at 18:13 +0200, Jose E. Marchesi wrote:
>> - "noreturn" and jump tables run-time hints
>> 
>>   It has been expressed on the kernel side the desire of having the C compiler
>>   emit run-time hints marking functions that are not supposed to return and
>>   also to provide annotations on jump tables.  This is for the benefit of
>>   objtool in arm64, see references below.
>> 
>>   Goal of the discussion:
>> 
>>   Collect and assess the requirements of these features, discuss their
>>   pertinence and the way it could be best implemented.  The outcome of the
>>   discussion will then be used to continue the discussion with the clang/llvm
>>   and kernel hackers at LPC.
>> 
>>   References:
>>   https://lore.kernel.org/linux-arm-kernel/YyLmhUxTUaNzaieC@hirez.programming.kicks-ass.net/
>
> FWIW we are having very similar issues for using objtool in loongarch. 
> And we also hit a similar issue with table-based computed goto.  I'm not
> sure if the computed goto is an issue for arm64 either.

I brought it up briefly on your behalf.

>
> Some related materials:
>
> - https://gcc.gnu.org/PR82365#c13
> - https://gcc.gnu.org/PR116483
> - https://gcc.gnu.org/pipermail/gcc-patches/2024-July/657641.html
> (Nacked off-line)