Re: [PATCH v2] net/virtio: fix build error with clang
From: Jerin Jacob <hidden>
Date: 2016-09-23 06:35:36
On Fri, Sep 23, 2016 at 02:15:09PM +0800, Yuanhan Liu wrote: Hi Yuanhan, Thanks for this patch.
Interestingly, clang and gcc has different prototype for _mm_prefetch().
For gcc, we have
_mm_prefetch (const void *__P, enum _mm_hint __I)
While for clang, it's
#define _mm_prefetch(a, sel) (__builtin_prefetch((void *)(a), 0, (sel)))
That how the following error comes with clang:
error: cast from 'const void *' to 'void *' drops const qualifier
[-Werror,-Wcast-qual]
_mm_prefetch((const void *)rused, _MM_HINT_T0);
/usr/lib/llvm-3.8/bin/../lib/clang/3.8.0/include/xmmintrin.h:684:58:
note: expanded from macro '_mm_prefetch'
#define _mm_prefetch(a, sel) (__builtin_prefetch((void *)(a),
0, (sel)))
What's weird is that the build was actaully Okay before. I met it while
apply Jerin's vector support for ARM patch set: he just move this peiece
of code to another file, nothing else changed.
This patch fix the issue when Jerin's patchset is applied. Thus, I think
it's still needed.The info notes can be moved under the "---" marker line to make git log clean. This patch review is holding the virtio arm NEON support. Appreciate any help in reviewing this patch. http://dpdk.org/dev/patchwork/patch/14567/
quoted hunk ↗ jump to hunk
Fixes: fc3d66212fed ("virtio: add vector Rx") Cc: Jerin Jacob <redacted> Signed-off-by: Yuanhan Liu <redacted> --- v2: replace _mm_prefetch with rte_prefetch0 to make icc happy --- drivers/net/virtio/virtio_rxtx_simple.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/net/virtio/virtio_rxtx_simple.c b/drivers/net/virtio/virtio_rxtx_simple.c index 6517aa8..d8dd17c 100644 --- a/drivers/net/virtio/virtio_rxtx_simple.c +++ b/drivers/net/virtio/virtio_rxtx_simple.c@@ -200,7 +200,7 @@ virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts, sw_ring = &vq->sw_ring[desc_idx]; sw_ring_end = &vq->sw_ring[vq->vq_nentries]; - _mm_prefetch((const void *)rused, _MM_HINT_T0); + rte_prefetch0(rused); if (vq->vq_free_cnt >= RTE_VIRTIO_VPMD_RX_REARM_THRESH) { virtio_rxq_rearm_vec(rxvq);-- 1.9.0