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From d31a18bcaaa3f3dd5f0bf8db705089c42c7ab0b3 Mon Sep 17 00:00:00 2001
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From: Andreas Schneider <asn@samba.org>
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Date: Thu, 14 Nov 2013 18:36:41 +0100
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Subject: [PATCH] util: Remove 32bit macros breaking strict aliasing.
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BUG: https://bugzilla.samba.org/show_bug.cgi?id=10269
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These macros might have worked but they break strict aliasing in the
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meantime and so the compiler is not able to optimize the relevant code.
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Signed-off-by: Andreas Schneider <asn@samba.org>
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Reviewed-by: Volker Lendecke <vl@samba.org>
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Autobuild-User(master): Volker Lendecke <vl@samba.org>
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Autobuild-Date(master): Thu Nov 14 23:16:45 CET 2013 on sn-devel-104
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(cherry picked from commit af69cb2a78810e608ccff115b433801a58a749e4)
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Signed-off-by: Andreas Schneider <asn@samba.org>
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---
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lib/util/byteorder.h | 52 ++--------------------------------------------------
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1 file changed, 2 insertions(+), 50 deletions(-)
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diff --git a/lib/util/byteorder.h b/lib/util/byteorder.h
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index 6bcf71e..58cd68a 100644
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--- a/lib/util/byteorder.h
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+++ b/lib/util/byteorder.h
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@@ -35,15 +35,6 @@ Here is a description of this file that I emailed to the samba list once:
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sure.
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-The distinction between 386 and other architectures is only there as
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-an optimisation. You can take it out completely and it will make no
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-difference. The routines (macros) in byteorder.h are totally byteorder
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-independent. The 386 optimsation just takes advantage of the fact that
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-the x86 processors don't care about alignment, so we don't have to
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-align ints on int boundaries etc. If there are other processors out
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-there that aren't alignment sensitive then you could also define
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-CAREFUL_ALIGNMENT=0 on those processors as well.
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-
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Ok, now to the macros themselves. I'll take a simple example, say we
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want to extract a 2 byte integer from a SMB packet and put it into a
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type called uint16_t that is in the local machines byte order, and you
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@@ -130,20 +121,6 @@ static __inline__ void st_le32(uint32_t *addr, const uint32_t val)
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#define HAVE_ASM_BYTEORDER 0
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#endif
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-
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-
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-#undef CAREFUL_ALIGNMENT
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-
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-/* we know that the 386 can handle misalignment and has the "right"
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- byteorder */
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-#if defined(__i386__)
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-#define CAREFUL_ALIGNMENT 0
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-#endif
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-
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-#ifndef CAREFUL_ALIGNMENT
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-#define CAREFUL_ALIGNMENT 1
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-#endif
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-
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#define CVAL(buf,pos) ((unsigned int)(((const uint8_t *)(buf))[pos]))
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#define CVAL_NC(buf,pos) (((uint8_t *)(buf))[pos]) /* Non-const version of CVAL */
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#define PVAL(buf,pos) (CVAL(buf,pos))
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@@ -161,7 +138,7 @@ static __inline__ void st_le32(uint32_t *addr, const uint32_t val)
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#define SSVALS(buf,pos,val) SSVAL((buf),(pos),((int16_t)(val)))
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#define SIVALS(buf,pos,val) SIVAL((buf),(pos),((int32_t)(val)))
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-#elif CAREFUL_ALIGNMENT
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+#else /* not HAVE_ASM_BYTEORDER */
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#define SVAL(buf,pos) (PVAL(buf,pos)|PVAL(buf,(pos)+1)<<8)
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#define IVAL(buf,pos) (SVAL(buf,pos)|SVAL(buf,(pos)+2)<<16)
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@@ -174,32 +151,7 @@ static __inline__ void st_le32(uint32_t *addr, const uint32_t val)
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#define SSVALS(buf,pos,val) SSVALX((buf),(pos),((int16_t)(val)))
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#define SIVALS(buf,pos,val) SIVALX((buf),(pos),((int32_t)(val)))
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-#else /* not CAREFUL_ALIGNMENT */
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-
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-/* this handles things for architectures like the 386 that can handle
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- alignment errors */
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-/*
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- WARNING: This section is dependent on the length of int16_t and int32_t
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- being correct
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-*/
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-
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-/* get single value from an SMB buffer */
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-#define SVAL(buf,pos) (*(const uint16_t *)((const char *)(buf) + (pos)))
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-#define SVAL_NC(buf,pos) (*(uint16_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */
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-#define IVAL(buf,pos) (*(const uint32_t *)((const char *)(buf) + (pos)))
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-#define IVAL_NC(buf,pos) (*(uint32_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */
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-#define SVALS(buf,pos) (*(const int16_t *)((const char *)(buf) + (pos)))
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-#define SVALS_NC(buf,pos) (*(int16_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */
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-#define IVALS(buf,pos) (*(const int32_t *)((const char *)(buf) + (pos)))
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-#define IVALS_NC(buf,pos) (*(int32_t *)((void *)((char *)(buf) + (pos)))) /* Non const version of above. */
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-
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-/* store single value in an SMB buffer */
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-#define SSVAL(buf,pos,val) SVAL_NC(buf,pos)=((uint16_t)(val))
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-#define SIVAL(buf,pos,val) IVAL_NC(buf,pos)=((uint32_t)(val))
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-#define SSVALS(buf,pos,val) SVALS_NC(buf,pos)=((int16_t)(val))
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-#define SIVALS(buf,pos,val) IVALS_NC(buf,pos)=((int32_t)(val))
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-
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-#endif /* not CAREFUL_ALIGNMENT */
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+#endif /* not HAVE_ASM_BYTEORDER */
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/* 64 bit macros */
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#define BVAL(p, ofs) (IVAL(p,ofs) | (((uint64_t)IVAL(p,(ofs)+4)) << 32))
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--
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1.8.4
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