From f490c51dd1b06ab77326ae3a546b076ce73e29f4 Mon Sep 17 00:00:00 2001 From: Andreas Schneider Date: Thu, 14 Nov 2013 18:36:41 +0100 Subject: [PATCH] util: Remove 32bit macros breaking strict aliasing. BUG: https://bugzilla.samba.org/show_bug.cgi?id=10269 These macros might have worked but they break strict aliasing in the meantime and so the compiler is not able to optimize the relevant code. Signed-off-by: Andreas Schneider Reviewed-by: Volker Lendecke Autobuild-User(master): Volker Lendecke Autobuild-Date(master): Thu Nov 14 23:16:45 CET 2013 on sn-devel-104 (cherry picked from commit af69cb2a78810e608ccff115b433801a58a749e4) Signed-off-by: Andreas Schneider --- lib/util/byteorder.h | 52 ++-------------------------------------------------- 1 file changed, 2 insertions(+), 50 deletions(-) diff --git a/lib/util/byteorder.h b/lib/util/byteorder.h index 6bcf71e..58cd68a 100644 --- a/lib/util/byteorder.h +++ b/lib/util/byteorder.h @@ -35,15 +35,6 @@ Here is a description of this file that I emailed to the samba list once: sure. -The distinction between 386 and other architectures is only there as -an optimisation. You can take it out completely and it will make no -difference. The routines (macros) in byteorder.h are totally byteorder -independent. The 386 optimsation just takes advantage of the fact that -the x86 processors don't care about alignment, so we don't have to -align ints on int boundaries etc. If there are other processors out -there that aren't alignment sensitive then you could also define -CAREFUL_ALIGNMENT=0 on those processors as well. - Ok, now to the macros themselves. I'll take a simple example, say we want to extract a 2 byte integer from a SMB packet and put it into a type called uint16_t that is in the local machines byte order, and you @@ -130,20 +121,6 @@ static __inline__ void st_le32(uint32_t *addr, const uint32_t val) #define HAVE_ASM_BYTEORDER 0 #endif - - -#undef CAREFUL_ALIGNMENT - -/* we know that the 386 can handle misalignment and has the "right" - byteorder */ -#if defined(__i386__) -#define CAREFUL_ALIGNMENT 0 -#endif - -#ifndef CAREFUL_ALIGNMENT -#define CAREFUL_ALIGNMENT 1 -#endif - #define CVAL(buf,pos) ((unsigned int)(((const uint8_t *)(buf))[pos])) #define CVAL_NC(buf,pos) (((uint8_t *)(buf))[pos]) /* Non-const version of CVAL */ #define PVAL(buf,pos) (CVAL(buf,pos)) @@ -161,7 +138,7 @@ static __inline__ void st_le32(uint32_t *addr, const uint32_t val) #define SSVALS(buf,pos,val) SSVAL((buf),(pos),((int16_t)(val))) #define SIVALS(buf,pos,val) SIVAL((buf),(pos),((int32_t)(val))) -#elif CAREFUL_ALIGNMENT +#else /* not HAVE_ASM_BYTEORDER */ #define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8) #define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16) @@ -174,32 +151,7 @@ static __inline__ void st_le32(uint32_t *addr, const uint32_t val) #define SSVALS(buf,pos,val) SSVALX((buf),(pos),((int16_t)(val))) #define SIVALS(buf,pos,val) SIVALX((buf),(pos),((int32_t)(val))) -#else /* not CAREFUL_ALIGNMENT */ - -/* this handles things for architectures like the 386 that can handle - alignment errors */ -/* - WARNING: This section is dependent on the length of int16_t and int32_t - being correct -*/ - -/* get single value from an SMB buffer */ -#define SVAL(buf,pos) (*(const uint16_t *)((const char *)(buf) + (pos))) -#define SVAL_NC(buf,pos) (*(uint16_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */ -#define IVAL(buf,pos) (*(const uint32_t *)((const char *)(buf) + (pos))) -#define IVAL_NC(buf,pos) (*(uint32_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */ -#define SVALS(buf,pos) (*(const int16_t *)((const char *)(buf) + (pos))) -#define SVALS_NC(buf,pos) (*(int16_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */ -#define IVALS(buf,pos) (*(const int32_t *)((const char *)(buf) + (pos))) -#define IVALS_NC(buf,pos) (*(int32_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */ - -/* store single value in an SMB buffer */ -#define SSVAL(buf,pos,val) SVAL_NC(buf,pos)=((uint16_t)(val)) -#define SIVAL(buf,pos,val) IVAL_NC(buf,pos)=((uint32_t)(val)) -#define SSVALS(buf,pos,val) SVALS_NC(buf,pos)=((int16_t)(val)) -#define SIVALS(buf,pos,val) IVALS_NC(buf,pos)=((int32_t)(val)) - -#endif /* not CAREFUL_ALIGNMENT */ +#endif /* not HAVE_ASM_BYTEORDER */ /* 64 bit macros */ #define BVAL(p, ofs) (IVAL(p,ofs) | (((uint64_t)IVAL(p,(ofs)+4)) << 32)) -- 1.8.4