From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [PATCH] ixgbe: fix clang compile - remove truncation errors Date: Sat, 29 Nov 2014 20:05:14 -0500 Message-ID: <20141130010514.GA19479@localhost.localdomain> References: <1417188660-14587-1-git-send-email-bruce.richardson@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: dev-VfR2kkLFssw@public.gmane.org To: Bruce Richardson Return-path: Content-Disposition: inline In-Reply-To: <1417188660-14587-1-git-send-email-bruce.richardson-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" On Fri, Nov 28, 2014 at 03:31:00PM +0000, Bruce Richardson wrote: > When compiling with clang, errors were being emitted due to truncation > of values when assigning to the tx_offload_mask bit fields. > > dpdk.org/lib/librte_pmd_ixgbe/ixgbe_rxtx.c:404:27: fatal error: implicit truncation from 'int' to bitfield changes value from -1 to 127 [-Wbitfield-constant-conversion] > tx_offload_mask.l2_len = ~0; > > The fix proposed here is to define a static const value of the same type > with all fields set to 1s, and use that instead of constants for assigning to. > > Other options would be to explicitily define the suitable constants that > would not truncate for each individual field e.g. 0x7f for l2_len, 0x1FF > for l3_len, etc., but this solution here has the advantage that it works > without any changes to values if the field sizes are ever modified. > > Signed-off-by: Bruce Richardson > --- > lib/librte_pmd_ixgbe/ixgbe_rxtx.c | 29 +++++++++++++++-------------- > 1 file changed, 15 insertions(+), 14 deletions(-) > > diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > index 8559ef6..4f71194 100644 > --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c > @@ -367,6 +367,7 @@ ixgbe_set_xmit_ctx(struct igb_tx_queue* txq, > volatile struct ixgbe_adv_tx_context_desc *ctx_txd, > uint64_t ol_flags, union ixgbe_tx_offload tx_offload) > { > + static const union ixgbe_tx_offload offload_allones = { .data = ~0 }; Do you want to make this a static data structure? If you make it a macro like this: #define ALLONES {.data = ~0} Then you save the extra data space in the .data area (not that its that much), and you can define it in a header file and use it in multiple c files (if you need to) Neil