[dpdk-dev] [PATCH 4/4] net: replace ifdefs with runtime branches

[Bruce Richardson]

Use the flag checking functions and a couple of empty stubs to remove the
ifdefs from the middle of the C code, and replace them with more readable
regular if statements. Other ifdefs at the top of the file are kept, but
are not mixed with C code, so there is a clean separation.

Signed-off-by: Bruce Richardson <bruce.richard...@intel.com>
---
 lib/librte_net/rte_net_crc.c | 38 ++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/lib/librte_net/rte_net_crc.c b/lib/librte_net/rte_net_crc.c
index dca0830e2..3b8a09504 100644
--- a/lib/librte_net/rte_net_crc.c
+++ b/lib/librte_net/rte_net_crc.c
@@ -18,8 +18,17 @@
 
 #ifdef X86_64_SSE42_PCLMULQDQ
 #include <net_crc_sse.h>
-#elif defined ARM64_NEON_PMULL
+#else
+/* define stubs for the SSE functions to avoid compiler errors */
+#define handlers_sse42 handlers_scalar
+#define rte_net_crc_sse42_init() do { } while(0)
+#endif
+
+#ifdef ARM64_NEON_PMULL
 #include <net_crc_neon.h>
+#else
+#define handlers_neon handlers_scalar
+#define rte_net_crc_neon_init() do { } while(0)
 #endif
 
 /* crc tables */
@@ -140,18 +149,19 @@ void
 rte_net_crc_set_alg(enum rte_net_crc_alg alg)
 {
        switch (alg) {
-#ifdef X86_64_SSE42_PCLMULQDQ
        case RTE_NET_CRC_SSE42:
-               handlers = handlers_sse42;
-               break;
-#elif defined ARM64_NEON_PMULL
+               if (rte_cpu_get_flagname_enabled(rte_cpu_arch_x86,
+                               "RTE_CPUFLAG_SSE4_2")) {
+                       handlers = handlers_sse42;
+                       break;
+               }
                /* fall-through */
        case RTE_NET_CRC_NEON:
-               if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_PMULL)) {
+               if (rte_cpu_get_flagname_enabled(rte_cpu_arch_arm,
+                               "RTE_CPUFLAG_PMULL")) {
                        handlers = handlers_neon;
                        break;
                }
-#endif
                /* fall-through */
        case RTE_NET_CRC_SCALAR:
                /* fall-through */
@@ -182,15 +192,17 @@ RTE_INIT(rte_net_crc_init)
 
        rte_net_crc_scalar_init();
 
-#ifdef X86_64_SSE42_PCLMULQDQ
-       alg = RTE_NET_CRC_SSE42;
-       rte_net_crc_sse42_init();
-#elif defined ARM64_NEON_PMULL
-       if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_PMULL)) {
+       if (rte_cpu_get_flagname_enabled(rte_cpu_arch_x86,
+                       "RTE_CPUFLAG_SSE4_2")) {
+               alg = RTE_NET_CRC_SSE42;
+               rte_net_crc_sse42_init();
+       }
+
+       if (rte_cpu_get_flagname_enabled(rte_cpu_arch_arm,
+                       "RTE_CPUFLAG_PMULL")) {
                alg = RTE_NET_CRC_NEON;
                rte_net_crc_neon_init();
        }
-#endif
 
        rte_net_crc_set_alg(alg);
 }
-- 
2.21.0