[dpdk-dev] [RFC PATCH v2] config/arm: replace native machine args

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

There are compiler issues when building with -mcpu=native with popular
compilers, such as GCC-8.4:
In file included from ../lib/librte_eal/arm/include/rte_vect.h:11,
                 from ../lib/librte_net/net_crc_neon.c:10:
../lib/librte_net/net_crc_neon.c: In function ‘crcr32_folding_round’:
/usr/lib/gcc/aarch64-linux-gnu/8/include/arm_neon.h:26094:1: error:
inlining failed in call to always_inline ‘vmull_p64’: target
specific option mismatch
 vmull_p64 (poly64_t a, poly64_t b)
 ^~~~~~~~~
../lib/librte_net/net_crc_neon.c:50:20: note: called from here
  uint64x2_t tmp1 = vreinterpretq_u64_p128(vmull_p64(
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    vgetq_lane_p64(vreinterpretq_p64_u64(fold), 0),
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    vgetq_lane_p64(vreinterpretq_p64_u64(precomp), 1)));
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

and clang:
gcc -E -dM -mcpu="native" - < /dev/null | grep __ARM_FEATURE_ATOMICS
clang-9 -E -dM -mcpu="native" - < /dev/null | grep __ARM_FEATURE_ATOMICS
<no output> # no clang support

Fix this by always specifying the proper machine args and never using
the native flags.

Fixes: 78ac8eac7e8a ("config/arm: use native machine build arguments")
Cc: juraj.linkes@pantheon.tech

Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
---
 config/arm/meson.build | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/config/arm/meson.build b/config/arm/meson.build
index f207e5a288..f948768578 100644
--- a/config/arm/meson.build
+++ b/config/arm/meson.build
@@ -24,7 +24,6 @@ flags_common = [
 	['RTE_ARCH_ARM64', true],
 	['RTE_CACHE_LINE_SIZE', 128]
 ]
-native_machine_args = ['-mcpu=native']
 
 ## Part numbers are specific to Arm implementers
 # implementer specific aarch64 flags have middle priority
@@ -193,7 +192,6 @@ if dpdk_conf.get('RTE_ARCH_32')
 	machine_args += '-mfpu=neon'
 else
 	# aarch64 build
-	use_native_machine_args = false
 	if not meson.is_cross_build()
 		if machine == 'default'
 			# default build
@@ -213,7 +211,6 @@ else
 			else
 				error('Error when getting Arm Implementer ID and part number.')
 			endif
-			use_native_machine_args = true
 		endif
 	else
 		# cross build
@@ -249,12 +246,7 @@ else
 
 	# apply supported machine args
 	machine_args = [] # Clear previous machine args
-	if use_native_machine_args
-		candidate_machine_args = native_machine_args
-	else
-		candidate_machine_args = part_number_config['machine_args']
-	endif
-	foreach flag: candidate_machine_args
+	foreach flag: part_number_config['machine_args']
 		if cc.has_argument(flag)
 			machine_args += flag
 		endif
-- 
2.20.1