Re: [dpdk-dev] [PATCH v2] eal: fix rte_memcpy build on ppc with gcc 9.3

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 5/4/2020 10:03 PM, David Christensen wrote:
> Building DPDK on Ubuntu 20.04 with GCC 9.3.0 results in a "subscript is
> outside array bounds" message in rte_memcpy function.  The build error
> is caused by an interaction between __builtin_constant_p and
> "-Werror=array-bounds" as described in this bugzilla:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90387
> 
> Modify the code to disable the array-bounds check for GCC versions 9.0
> to 9.3.
> 
> Signed-off-by: David Christensen <drc@linux.vnet.ibm.com>
> ---
> 
> v2:
> * Replace __GNUC__ and __GNUC_MINOR__ with GCC_VERSION
> ---
>  lib/librte_eal/ppc/include/rte_memcpy.h | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_eal/ppc/include/rte_memcpy.h b/lib/librte_eal/ppc/include/rte_memcpy.h
> index 25311ba1d..de47a5d2e 100644
> --- a/lib/librte_eal/ppc/include/rte_memcpy.h
> +++ b/lib/librte_eal/ppc/include/rte_memcpy.h
> @@ -8,8 +8,8 @@
>  
>  #include <stdint.h>
>  #include <string.h>
> -/*To include altivec.h, GCC version must  >= 4.8 */
> -#include <altivec.h>
> +#include "rte_altivec.h"
> +#include "rte_common.h"

I can't find "rte_altivec.h", am I missing something.

With just ignoring "-Warray-bounds" changes, I confirm ena build issue is fixed
with gcc 9.1

>  
>  #ifdef __cplusplus
>  extern "C" {
> @@ -17,6 +17,11 @@ extern "C" {
>  
>  #include "generic/rte_memcpy.h"
>  
> +#if (GCC_VERSION >= 90000 && GCC_VERSION < 90400)
> +#pragma GCC diagnostic push
> +#pragma GCC diagnostic ignored "-Warray-bounds"
> +#endif
> +
>  static inline void
>  rte_mov16(uint8_t *dst, const uint8_t *src)
>  {
> @@ -192,6 +197,10 @@ rte_memcpy_func(void *dst, const void *src, size_t n)
>  	return ret;
>  }
>  
> +#if (GCC_VERSION >= 90000 && GCC_VERSION < 90400)
> +#pragma GCC diagnostic pop
> +#endif
> +
>  #ifdef __cplusplus
>  }
>  #endif
>