[v2,2/4] mempool/octeontx2: fix build for gcc O1 optimization
Checks
Commit Message
Can be reproduced with "make EXTRA_CFLAGS='-O1'" command using
gcc (GCC) 9.3.1 20200408 (Red Hat 9.3.1-2)
Build error:
In file included from .../drivers/mempool/octeontx2/otx2_mempool.h:13,
from .../drivers/mempool/octeontx2/otx2_mempool_ops.c:8:
.../drivers/mempool/octeontx2/otx2_mempool_ops.c:
In function ‘otx2_npa_alloc’:
.../drivers/common/octeontx2/otx2_common.h:94:2:
error: ‘aura_handle’ may be used uninitialized in this function
[-Werror=maybe-uninitialized]
94 | rte_log(RTE_LOG_DEBUG, otx2_logtype_ ## subsystem, \
| ^~~~~~~
.../drivers/mempool/octeontx2/otx2_mempool_ops.c:643:11:
note: ‘aura_handle’ was declared here
643 | uint64_t aura_handle;
| ^~~~~~~~~~~
This looks like false positive, assigning an initial value to
'aura_handle' to fix the build error.
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
This is assuming assigning initial value won't have a performance affect
if it does, we need to find another fix.
And overall not sure why this false positive warning is generated.
---
drivers/mempool/octeontx2/otx2_mempool_ops.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Comments
On Fri, May 8, 2020 at 10:16 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>
> Can be reproduced with "make EXTRA_CFLAGS='-O1'" command using
> gcc (GCC) 9.3.1 20200408 (Red Hat 9.3.1-2)
>
> Build error:
> In file included from .../drivers/mempool/octeontx2/otx2_mempool.h:13,
> from .../drivers/mempool/octeontx2/otx2_mempool_ops.c:8:
> .../drivers/mempool/octeontx2/otx2_mempool_ops.c:
> In function ‘otx2_npa_alloc’:
> .../drivers/common/octeontx2/otx2_common.h:94:2:
> error: ‘aura_handle’ may be used uninitialized in this function
> [-Werror=maybe-uninitialized]
> 94 | rte_log(RTE_LOG_DEBUG, otx2_logtype_ ## subsystem, \
> | ^~~~~~~
> .../drivers/mempool/octeontx2/otx2_mempool_ops.c:643:11:
> note: ‘aura_handle’ was declared here
> 643 | uint64_t aura_handle;
> | ^~~~~~~~~~~
>
> This looks like false positive, assigning an initial value to
> 'aura_handle' to fix the build error.
>
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
> This is assuming assigning initial value won't have a performance affect
> if it does, we need to find another fix.
> And overall not sure why this false positive warning is generated.
> ---
> drivers/mempool/octeontx2/otx2_mempool_ops.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mempool/octeontx2/otx2_mempool_ops.c b/drivers/mempool/octeontx2/otx2_mempool_ops.c
> index 162b7f01da..078ffac3e2 100644
> --- a/drivers/mempool/octeontx2/otx2_mempool_ops.c
> +++ b/drivers/mempool/octeontx2/otx2_mempool_ops.c
> @@ -640,7 +640,7 @@ otx2_npa_alloc(struct rte_mempool *mp)
> struct otx2_npa_lf *lf;
> struct npa_aura_s aura;
> struct npa_pool_s pool;
> - uint64_t aura_handle;
> + uint64_t aura_handle = 0;
It is a false positive. Since it is on a slow path, This workaround is OK.
While merging t this patch, Could you move "uint64_t aura_handle = 0;"
just before "struct otx2_npa_lf *lf" as
the variables are ordered in reverse xmas tree format in this file.
With the above change:
Acked-by: Jerin Jacob <jerinj@marvell.com>
> size_t padding;
> int rc;
>
> --
> 2.25.4
>
@@ -640,7 +640,7 @@ otx2_npa_alloc(struct rte_mempool *mp)
struct otx2_npa_lf *lf;
struct npa_aura_s aura;
struct npa_pool_s pool;
- uint64_t aura_handle;
+ uint64_t aura_handle = 0;
size_t padding;
int rc;