[dpdk-dev] [PATCH 1/2] eal/arm: fix gcc build for optimization level 0

[David Marchand]

On Fri, Nov 27, 2020 at 9:10 AM Ruifeng Wang <ruifeng.wang at arm.com> wrote:
>
> Gcc build with '-O0' on platforms with RTE_ARM_FEATURE_ATOMICS set
> failed for:
>  ../lib/librte_efd/rte_efd.c
>  Assembler messages:
> 3866: Error: selected processor does not support `crc32cb w0,w0,w1'
> 3890: Error: selected processor does not support `crc32ch w0,w0,w1'
> 3914: Error: selected processor does not support `crc32cw w0,w0,w1'
> 3938: Error: selected processor does not support `crc32cx w0,w0,x1'
>
> This was caused by an architecture specifier added for Clang.
> Unlike Clang, Gcc considers each inline assembly block to be dependent
> and therefor, the architecture specifier impacts assemble of some
> blocks require certain extension support.

I reproduced this error with -O0 for config/arm/arm64_octeontx2_linux_gcc.
The patch looks simple enough and it only affects ARM builds.

Jerin,
Are you okay with this change for 20.11?
Or should we wait 21.02?

Ruifeng,
Looking at the kernel, I see no distinction with gcc/clang, so I'd say
the kernel has the same issue, or is there something else that differs
in dpdk?
Besides, the kernel patch previously mentioned had a followup fix.


-- 
David Marchand