[PATCH v4 36/39] fib: use C11 alignas

[Tyler Retzlaff]

* Move __rte_aligned from the end of {struct,union} definitions to
  be between {struct,union} and tag.

  The placement between {struct,union} and the tag allows the desired
  alignment to be imparted on the type regardless of the toolchain being
  used for all of GCC, LLVM, MSVC compilers building both C and C++.

* Replace use of __rte_aligned(a) on variables/fields with alignas(a).

Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
Acked-by: Morten Brørup <m...@smartsharesystems.com>
---
 lib/fib/dir24_8.h | 4 +++-
 lib/fib/trie.h    | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/fib/dir24_8.h b/lib/fib/dir24_8.h
index b0d1a40..6d350f7 100644
--- a/lib/fib/dir24_8.h
+++ b/lib/fib/dir24_8.h
@@ -6,6 +6,8 @@
 #ifndef _DIR24_8_H_
 #define _DIR24_8_H_
 
+#include <stdalign.h>
+
 #include <rte_prefetch.h>
 #include <rte_branch_prediction.h>
 
@@ -32,7 +34,7 @@ struct dir24_8_tbl {
        uint64_t        *tbl8;          /**< tbl8 table. */
        uint64_t        *tbl8_idxes;    /**< bitmap containing free tbl8 idxes*/
        /* tbl24 table. */
-       __extension__ uint64_t  tbl24[0] __rte_cache_aligned;
+       __extension__ alignas(RTE_CACHE_LINE_SIZE) uint64_t     tbl24[0];
 };
 
 static inline void *
diff --git a/lib/fib/trie.h b/lib/fib/trie.h
index 3cf161a..36ce1fd 100644
--- a/lib/fib/trie.h
+++ b/lib/fib/trie.h
@@ -6,6 +6,8 @@
 #ifndef _TRIE_H_
 #define _TRIE_H_
 
+#include <stdalign.h>
+
 /**
  * @file
  * RTE IPv6 Longest Prefix Match (LPM)
@@ -36,7 +38,7 @@ struct rte_trie_tbl {
        uint32_t        *tbl8_pool;     /**< bitmap containing free tbl8 idxes*/
        uint32_t        tbl8_pool_pos;
        /* tbl24 table. */
-       __extension__ uint64_t  tbl24[0] __rte_cache_aligned;
+       __extension__ alignas(RTE_CACHE_LINE_SIZE) uint64_t     tbl24[0];
 };
 
 static inline uint32_t
-- 
1.8.3.1