On 2024-01-16 19:41, Stephen Hemminger wrote:
Both Gcc, clang and MSVC have better way to do compile time
assertions rather than using out of bounds array access.
The old method would fail if -Wvla is enabled because compiler
can't determine size in that code. Also, the use of new
_Static_assert will catch broken code that is passing non-constant
expression to RTE_BUILD_BUG_ON().
Need to add brackets {} around the static_assert() to workaround
a bug in clang. Clang was not handling static_assert() in
a switch case properly.
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
Acked-by: Morten Brørup <m...@smartsharesystems.com>
Acked-by: Tyler Retzlaff <roret...@linux.microsoft.com>
---
lib/eal/include/rte_common.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
index c1ba32d00e47..413bed23cb73 100644
--- a/lib/eal/include/rte_common.h
+++ b/lib/eal/include/rte_common.h
@@ -16,6 +16,7 @@
extern "C" {
#endif
+#include <assert.h>
#include <stdint.h>
#include <limits.h>
@@ -495,7 +496,7 @@ rte_is_aligned(const void * const __rte_restrict ptr, const unsigned int align)
/**
* Triggers an error at compilation time if the condition is true.
*/
-#define RTE_BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
+#define RTE_BUILD_BUG_ON(condition) { static_assert(!(condition), #condition);
}
/*********** Cache line related macros ********/
Should one use RTE_BUILD_BUG_ON() or static_assert() in new DPDK code?
If static_assert() occasionally needs a work-around, it sounds like
keeping using RTE_BUILD_BUG_ON() everywhere is the better choice.
