> -----Original Message----- > From: Qiu, Michael > Sent: Tuesday, March 03, 2015 11:00 AM > To: Wodkowski, PawelX; dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH v2] librte_eal/common: Fix cast from pointer to > integer of different size > > On 3/3/2015 4:25 PM, Wodkowski, PawelX wrote: > > On 2015-03-03 03:20, Michael Qiu wrote: > >> /i686-native-linuxapp-gcc/include/rte_memcpy.h:592:23: error: > >> cast from pointer to integer of different size > >> [-Werror=pointer-to-int-cast] > >> > >> dstofss = 16 - (int)((long long)(void *)dst & 0x0F) + 16; > >> > >> Type 'long long' is 64-bit in i686 platform while 'void *' > >> is 32-bit. > >> > >> Signed-off-by: Michael Qiu <michael.qiu at intel.com> > >> --- > >> v2 --> v1: > >> Remove unnecessary casting (void *) > >> > >> lib/librte_eal/common/include/arch/x86/rte_memcpy.h | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >> diff --git a/lib/librte_eal/common/include/arch/x86/rte_memcpy.h > b/lib/librte_eal/common/include/arch/x86/rte_memcpy.h > >> index 7b2d382..85a5f4d 100644 > >> --- a/lib/librte_eal/common/include/arch/x86/rte_memcpy.h > >> +++ b/lib/librte_eal/common/include/arch/x86/rte_memcpy.h > >> @@ -589,12 +589,12 @@ COPY_BLOCK_64_BACK15: > >> * unaligned copy functions require up to 15 bytes > >> * backwards access. > >> */ > >> - dstofss = 16 - (int)((long long)(void *)dst & 0x0F) + 16; > >> + dstofss = 16 - (int)((long)dst & 0x0F) + 16; > >> n -= dstofss; > >> rte_mov32((uint8_t *)dst, (const uint8_t *)src); > >> src = (const uint8_t *)src + dstofss; > >> dst = (uint8_t *)dst + dstofss; > >> - srcofs = (int)((long long)(const void *)src & 0x0F); > >> + srcofs = (int)((long)src & 0x0F); > >> > >> /** > >> * For aligned copy > >> > > I think you should use here size_t, (u)ptrdiff_t or (u)intptr_t as this > > Yes, but 'long' is enough, does it limit anything, or has any issue with > multiple platforms? >
Those types ((u)ptrdiff_t, (u)intptr_t) exists specially for pointer-to-int and int-to-pointer casts. Using integer primitives might produce further warnings/error in the future and need further patches fixing the same place. Also why make offset variables signed and different type? This introduce a lot of unnecessary explicit and implicit casts or type promotions. > > will be more portable. > > Also type of dstofss and srcofs should be changed accordingly. > > No, I think, it should be offset. > > Thanks, > Michael > > -- Pawel
