On 10/23/2019 3:04 PM, Olivier Matz wrote: > On Wed, Oct 23, 2019 at 11:43:58AM +0000, Kiran Kumar Kokkilagadda wrote: >>> -----Original Message----- >>> From: Olivier Matz <olivier.m...@6wind.com> >>> Sent: Wednesday, October 23, 2019 5:09 PM >>> To: Raslan Darawsheh <rasl...@mellanox.com> >>> Cc: Ferruh Yigit <ferruh.yi...@intel.com>; Kiran Kumar Kokkilagadda >>> <kirankum...@marvell.com>; Adrien Mazarguil >>> <adrien.mazarg...@6wind.com>; Wenzhuo Lu <wenzhuo...@intel.com>; >>> Jingjing Wu <jingjing...@intel.com>; Bernard Iremonger >>> <bernard.iremon...@intel.com>; John McNamara >>> <john.mcnam...@intel.com>; Marko Kovacevic <marko.kovace...@intel.com>; >>> Thomas Monjalon <tho...@monjalon.net>; Andrew Rybchenko >>> <arybche...@solarflare.com>; dev@dpdk.org; ajit.khapa...@broadcom.com >>> Subject: [EXT] Re: [dpdk-dev] [PATCH v10] ethdev: add HIGIG2 key field to >>> flow >>> API >>> >>> External Email >>> >>> ---------------------------------------------------------------------- >>> Hi, >>> >>> >>> >>> On Wed, Oct 23, 2019 at 10:50:52AM +0000, Raslan Darawsheh wrote: >>> >>>> Hi, >>> >>>> >>> >>>> This patch broke the compilation of MLX5 PMD in debug mode: >>> >>>> >>> >>>> from /root/dpdk/x86_64-native-linux- >>> gcc/include/rte_ethdev_driver.h:18, >>> >>>> from /root/dpdk/drivers/net/mlx5/mlx5_mp.c:11: >>> >>>> /root/dpdk/x86_64-native-linux-gcc/include/rte_higig.h:112:2: error: type >>>> of >>> bit-field 'opcode' is a GCC extension [-Werror=pedantic] >>> >>>> uint16_t opcode:3; >>> >>>> ^ >>> >>>> /root/dpdk/x86_64-native-linux-gcc/include/rte_higig.h:113:2: error: type >>>> of >>> bit-field 'resv1' is a GCC extension [-Werror=pedantic] >>> >>>> uint16_t resv1:2; >>> >>>> ^ >>> >>>> /root/dpdk/x86_64-native-linux-gcc/include/rte_higig.h:114:2: error: type >>>> of >>> bit-field 'src_t' is a GCC extension [-Werror=pedantic] >>> >>>> uint16_t src_t:1; >>> >>>> ^ >>> >>>> /root/dpdk/x86_64-native-linux-gcc/include/rte_higig.h:115:2: error: type >>>> of >>> bit-field 'pfm' is a GCC extension [-Werror=pedantic] >>> >>>> uint16_t pfm:2; >>> >>>> ^ >>> >>>> /root/dpdk/x86_64-native-linux-gcc/include/rte_higig.h:116:2: error: type >>>> of >>> bit-field 'resv2' is a GCC extension [-Werror=pedantic] >>> >>>> uint16_t resv2:5; >>> >>>> ^ >>> >>>> /root/dpdk/x86_64-native-linux-gcc/include/rte_higig.h:117:2: error: type >>>> of >>> bit-field 'hdr_ext_len' is a GCC extension [-Werror=pedantic] >>> >>>> uint16_t hdr_ext_len:3; >>> >>>> >>> >>>> and this is with gcc 4.8.5 >>> >>> >>> >>> From https://urldefense.proofpoint.com/v2/url?u=https- >>> 3A__stackoverflow.com_questions_10906238_warning-2Dwhen-2Dusing- >>> 2Dbitfield-2Dwith-2Dunsigned- >>> 2Dchar&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=owEKckYY4FTmil1Z6oBUR >>> wkTThyuRbLAY9LdfiaT6HA&m=GZ- >>> 6cngPycaUlGJT20VEOf9oTcp5PMwk7j1JV1vAQfs&s=SCg5yVPS4zZa8GSn9bl_eUtI >>> vBmoDzi35PspWUttIUY&e= >>> >>> it seems that it is allowed in c99, so I guess it's a gcc 4.8 bug. >>> >>> >>> >>> Adding __extension__ above the struct solves the warnings, I suggest to >>> >>> add it. >> >> /** >> * >> * higig2 ppt type1 header. >> */ >> RTE_STD_C11 >> struct rte_higig2_ppt_type1 { >> uint16_t classification; >> uint16_t resv; >> uint16_t vid; >> #if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN >> uint16_t opcode:3; >> uint16_t resv1:2; >> uint16_t src_t:1; >> uint16_t pfm:2; >> uint16_t resv2:5; >> uint16_t hdr_ext_len:3; >> #elif RTE_BYTE_ORDER == RTE_BIG_ENDIAN >> uint16_t pfm:2; >> uint16_t src_t:1; >> uint16_t resv1:2; >> uint16_t opcode:3; >> uint16_t hdr_ext_len:3; >> uint16_t resv2:5; >> #endif >> }; >> >> I have already added it. RTE_STD_C11 , this is a macro for __extension__. >> /** C extension macro for environments lacking C11 features. */ >> #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L >> #define RTE_STD_C11 __extension__ >> #else >> #define RTE_STD_C11 >> #endif > > The __extension__ is only added if compiled for < c11. > But there is apparently a problem with gcc-4.8: even in c11, it does > not support bitfields on u16. See: https://godbolt.org/z/hRIbgg > > On gcc-4.9, the problem disappeared: https://godbolt.org/z/kkzz9v > > So as a workaround, using __extension__ should work, probably with a short > explanation. >
Thanks Olivier, this was also our finding with Raslan and he sent the fix already. https://patches.dpdk.org/patch/61748/ Also it looks like gcc4.8 thinks this is not c11 standard but extension only for uint16_t type, structs with uint32_t bit-fieds works as expected.
