Re: [dpdk-dev] [PATCH v2] build: fix SVE compile error with gcc8.3

[fengchengwen <fengchengwen@huawei.com>]

Fix in v3, also with minor changes, thanks

On 2021/5/20 21:09, Bruce Richardson wrote:
> On Thu, May 20, 2021 at 07:40:12PM +0800, Chengwen Feng wrote:
>> If the target machine has SVE feature (e.g. "-march=armv8.2-a+sve'),
>> and the compiler is gcc8.3, it will compile error:
>> 	In file included from ../dpdk-next-net/lib/eal/common/
>> 	eal_common_options.c:38:
>> 	../dpdk-next-net/lib/eal/arm/include/rte_vect.h:13:10: fatal
>> 	error: arm_sve.h: No such file or directory
>> 	#include <arm_sve.h>
>> 	       ^~~~~~~~~~~
>> 	compilation terminated.
>>
>> The root cause is that gcc8.3 support SVE (the macro __ARM_FEATURE_SVE
>> was 1), but it doesn't support SVE ACLE [1].
>>
>> The solution:
>> a) Detect compiler whether support SVE ACLE, if support then define
>> CC_SVE_ACLE_SUPPORT macro.
>> b) Use the CC_SVE_ACLE_SUPPORT macro to include SVE header file.
>>
>> [1] ACLE:  Arm C Language Extensions, the SVE ACLE header file is
>> <arm_sve.h>, user should include it when writing ACLE SVE code.
>>
>> Fixes: 67b68824a82d ("lpm/arm: support SVE")
>>
>> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
>> ---
>> v2: 
>> * modify title start with 'build'
>>
> 
> One minor comment inline below.
> /Bruce
>> ---
>>  config/arm/meson.build         | 5 +++++
>>  lib/eal/arm/include/rte_vect.h | 2 +-
>>  lib/lpm/rte_lpm.h              | 2 +-
>>  3 files changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/config/arm/meson.build b/config/arm/meson.build
>> index e83a56e..bff70e4 100644
>> --- a/config/arm/meson.build
>> +++ b/config/arm/meson.build
>> @@ -480,6 +480,11 @@ if (cc.get_define('__ARM_NEON', args: machine_args) != '' or
>>      compile_time_cpuflags += ['RTE_CPUFLAG_NEON']
>>  endif
>>  
>> +if (cc.get_define('__ARM_FEATURE_SVE', args: machine_args) != '' and
>> +    cc.check_header('arm_sve.h'))
> Please double-indent this line. It looks like part of the condition body
> as-is.
> 
> 
> .
>