[PATCH v5 16/39] timer: use C11 alignas

[Tyler Retzlaff]

The current location used for __rte_aligned(a) for alignment of types
and variables is not compatible with MSVC. There is only a single
location accepted by both toolchains.

For variables standard C11 offers alignas(a) supported by conformant
compilers i.e. both MSVC and GCC.

For types the standard offers no alignment facility that compatibly
interoperates with C and C++ but may be achieved by relocating the
placement of __rte_aligned(a) to the aforementioned location accepted
by all currently supported toolchains.

To allow alignment for both compilers do the following:

* 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 <roretzla at linux.microsoft.com>
Acked-by: Morten Brørup <mb at smartsharesystems.com>
---
 lib/timer/rte_timer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/timer/rte_timer.c b/lib/timer/rte_timer.c
index 53ed221..bb8b6a6 100644
--- a/lib/timer/rte_timer.c
+++ b/lib/timer/rte_timer.c
@@ -24,7 +24,7 @@
 /**
  * Per-lcore info for timers.
  */
-struct priv_timer {
+struct __rte_cache_aligned priv_timer {
 	struct rte_timer pending_head;  /**< dummy timer instance to head up list */
 	rte_spinlock_t list_lock;       /**< lock to protect list access */
 
@@ -44,7 +44,7 @@ struct priv_timer {
 	/** per-lcore statistics */
 	struct rte_timer_debug_stats stats;
 #endif
-} __rte_cache_aligned;
+};
 
 #define FL_ALLOCATED	(1 << 0)
 struct rte_timer_data {
-- 
1.8.3.1