On Fri, 14 Dec 2018 08:38:27 -0800
Jeff Shaw <jeffrey.b.s...@intel.com> wrote:
> Compilers that do not support the C11 standard, or do not implement
> gcc extensions, may not support variable length arrays.
>
> The code prior to this commit produced the following warning when
> compiled with "-Wvla -std=c90".
>
> warning: ISO C90 forbids variable length array ‘array’ [-Wvla]
>
> This commit removes the variable length array from the PMD debug
> trace function by allocating memory dynamically on the stack using
> alloca().
>
> Signed-off-by: Jeff Shaw <jeffrey.b.s...@intel.com>
> ---
> lib/librte_eal/common/include/rte_dev.h | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/lib/librte_eal/common/include/rte_dev.h
> b/lib/librte_eal/common/include/rte_dev.h
> index a9724dc91..af772872b 100644
> --- a/lib/librte_eal/common/include/rte_dev.h
> +++ b/lib/librte_eal/common/include/rte_dev.h
> @@ -47,22 +47,21 @@ __attribute__((format(printf, 2, 0)))
> static inline void
> rte_pmd_debug_trace(const char *func_name, const char *fmt, ...)
> {
> + char *buffer;
> + int buf_len;
> va_list ap;
>
> va_start(ap, fmt);
> + buf_len = vsnprintf(NULL, 0, fmt, ap) + 1;
> + va_end(ap);
>
> - {
> - char buffer[vsnprintf(NULL, 0, fmt, ap) + 1];
> + buffer = (char *)alloca(buf_len);
alloca is void * so cast is not necessary.
You might be able to skip the buffering step entirely by using rte_log
a little more creatively, see how other logging works.
But to go further since rte_pmd_debug_trace is not used anywhere in
current code base in DPDK, it should just be removed.
