[dpdk-dev] [PATCH v8 2/2] net/hns3: refactor SVE code compile method

[Chengwen Feng <fengchengwen@huawei.com>]

Currently, the SVE code is compiled only when -march supports SVE
(e.g. '-march=armv8.2a+sve'), there maybe some problem[1] with this
approach.

The solution:
a. If the minimum instruction set support SVE then compiles it.
b. Else if the compiler support SVE then compiles it.
c. Otherwise don't compile it.

Note: this patch also fixes compile error with gcc8.3 +
'-march=armv8.a+sve', the error is arm_sve.h no such file or directory.

[1] https://mails.dpdk.org/archives/dev/2021-April/208189.html

Fixes: 8c25b02b082a ("net/hns3: fix enabling SVE Rx/Tx")
Fixes: 952ebacce4f2 ("net/hns3: support SVE Rx")
Cc: stable@dpdk.org

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
---
 drivers/net/hns3/hns3_rxtx.c |  2 +-
 drivers/net/hns3/meson.build | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hns3/hns3_rxtx.c b/drivers/net/hns3/hns3_rxtx.c
index 1d7a769..9b2f082 100644
--- a/drivers/net/hns3/hns3_rxtx.c
+++ b/drivers/net/hns3/hns3_rxtx.c
@@ -2808,7 +2808,7 @@ hns3_get_default_vec_support(void)
 static bool
 hns3_get_sve_support(void)
 {
-#if defined(RTE_ARCH_ARM64) && defined(__ARM_FEATURE_SVE)
+#if defined(CC_SVE_ACLE_SUPPORT)
 	if (rte_vect_get_max_simd_bitwidth() < RTE_VECT_SIMD_256)
 		return false;
 	if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_SVE))
diff --git a/drivers/net/hns3/meson.build b/drivers/net/hns3/meson.build
index 53c7df7..aabcf23 100644
--- a/drivers/net/hns3/meson.build
+++ b/drivers/net/hns3/meson.build
@@ -35,7 +35,25 @@ deps += ['hash']
 
 if arch_subdir == 'arm' and dpdk_conf.get('RTE_ARCH_64')
     sources += files('hns3_rxtx_vec.c')
-    if cc.get_define('__ARM_FEATURE_SVE', args: machine_args) != ''
+
+    # compile SVE when:
+    # a. support SVE in minimum instruction set baseline
+    # b. it's not minimum instruction set, but compiler support
+    if dpdk_conf.has('CC_SVE_ACLE_SUPPORT')
         sources += files('hns3_rxtx_vec_sve.c')
+    elif cc.has_argument('-march=armv8.2-a+sve') and cc.check_header('arm_sve.h')
+        cflags += ['-DCC_SVE_ACLE_SUPPORT=1']
+        sve_cflags = []
+        foreach flag: cflags
+            if not (flag.startswith('-march=') or flag.startswith('-mcpu=') or flag.startswith('-mtune='))
+                sve_cflags += flag
+            endif
+        endforeach
+        hns3_sve_lib = static_library('hns3_sve_lib',
+                        'hns3_rxtx_vec_sve.c',
+                        dependencies: [static_rte_ethdev],
+                        include_directories: includes,
+                        c_args: [sve_cflags, '-march=armv8.2-a+sve'])
+        objs += hns3_sve_lib.extract_objects('hns3_rxtx_vec_sve.c')
     endif
 endif
-- 
2.8.1