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

[Andrew Rybchenko]

On 11/27/20 12:25 PM, David Marchand wrote:
> On Fri, Nov 27, 2020 at 9:51 AM Jerin Jacob <jerinjacobk at gmail.com> wrote:
>>
>> On Fri, Nov 27, 2020 at 2:09 PM David Marchand
>> <david.marchand at redhat.com> wrote:
>>>
>>> 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?
>>
>> I could reproduce the issue with meson  build -Dbuildtype=debug
>> --cross-file config/arm/arm64_octeontx2_linux_gcc
>>
>> This fix is OK. Request to merge for 20.11
>>
>> Acked-by: Jerin Jacob <jerinj at marvell.com>
> 
> Ruifeng, Andrew,
> 
> I get a compilation error with this patch on sfc using gcc and
> config/arm/arm64_octeontx2_linux_gcc config + --buildtype=debug and/or
> -Dc_args=-O0 .
> 
> aarch64-linux-gnu-gcc (GNU Toolchain for the A-profile Architecture
> 8.2-2019.01 (arm-rel-8.28)) 8.2.1 20180802
> 
> FAILED: drivers/common/sfc_efx/base/932d09a@@sfc_base at sta/efx_crc32.c.o
> aarch64-linux-gnu-gcc
> -Idrivers/common/sfc_efx/base/932d09a@@sfc_base at sta
> -Idrivers/common/sfc_efx/base -I../../dpdk/drivers/common/sfc_efx/base
> -Idrivers/common/sfc_efx -I../../dpdk/drivers/common/sfc_efx -I.
> -I../../dpdk/ -Iconfig -I../../dpdk/config -Ilib/librte_eal/include
> -I../../dpdk/lib/librte_eal/include -Ilib/librte_eal/linux/include
> -I../../dpdk/lib/librte_eal/linux/include -Ilib/librte_eal/arm/include
> -I../../dpdk/lib/librte_eal/arm/include -Ilib/librte_eal/common
> -I../../dpdk/lib/librte_eal/common -Ilib/librte_eal
> -I../../dpdk/lib/librte_eal -Ilib/librte_kvargs
> -I../../dpdk/lib/librte_kvargs
> -Ilib/librte_telemetry/../librte_metrics
> -I../../dpdk/lib/librte_telemetry/../librte_metrics
> -Ilib/librte_telemetry -I../../dpdk/lib/librte_telemetry
> -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall
> -Winvalid-pch -Werror -g -include rte_config.h -Wextra -Wcast-qual
> -Wdeprecated -Wformat -Wformat-nonliteral -Wformat-security
> -Wmissing-declarations -Wmissing-prototypes -Wnested-externs
> -Wold-style-definition -Wpointer-arith -Wsign-compare
> -Wstrict-prototypes -Wundef -Wwrite-strings -Wno-packed-not-aligned
> -Wno-missing-field-initializers -D_GNU_SOURCE -fPIC
> -march=armv8.2-a+crc+crypto+lse -DALLOW_EXPERIMENTAL_API
> -DALLOW_INTERNAL_API -Wno-format-truncation -Wdisabled-optimization
> -Waggregate-return -Wbad-function-cast -Wno-sign-compare
> -Wno-unused-parameter -Wno-unused-variable -Wno-empty-body
> -Wno-unused-but-set-variable -MD -MQ
> 'drivers/common/sfc_efx/base/932d09a@@sfc_base at sta/efx_crc32.c.o' -MF
> 'drivers/common/sfc_efx/base/932d09a@@sfc_base at sta/efx_crc32.c.o.d' -o
> 'drivers/common/sfc_efx/base/932d09a@@sfc_base at sta/efx_crc32.c.o' -c
> ../../dpdk/drivers/common/sfc_efx/base/efx_crc32.c
> In file included from ../../dpdk/lib/librte_eal/arm/include/rte_atomic.h:9,
>                  from ../../dpdk/lib/librte_eal/include/generic/rte_pause.h:19,
>                  from ../../dpdk/lib/librte_eal/arm/include/rte_pause_64.h:19,
>                  from ../../dpdk/lib/librte_eal/arm/include/rte_pause.h:13,
>                  from
> ../../dpdk/lib/librte_eal/include/generic/rte_spinlock.h:25,
>                  from ../../dpdk/lib/librte_eal/arm/include/rte_spinlock.h:17,
>                  from ../../dpdk/drivers/common/sfc_efx/efsys.h:15,
>                  from ../../dpdk/drivers/common/sfc_efx/base/efx.h:11,
>                  from ../../dpdk/drivers/common/sfc_efx/base/efx_crc32.c:7:

...

> If I waive those warnings:
> - next to fail is net/igc (fixed by next patch so ok)
> - and then next to fail is net/sfc.

As I understand it is not common/sfc_efx specific issue since it is
simply header inclusion. I guess it is the just first
one to build. I have no good ideas what to do with it.
So, help from ARM experts would be appreciated.

Andrew.