user/sven/git.git/block-sha1, branch v1.8.0.2

Merge branch 'jn/block-sha1'

2012-07-24T03:56:47Z

The code to load a word one-byte-at-a-time was optimized into a word-wide load instruction even when the pointer was not aligned, which caused issues on architectures that do not like unaligned access. * jn/block-sha1: Makefile: BLK_SHA1 does not require fast htonl() and unaligned loads block-sha1: put expanded macro parameters in parentheses block-sha1: avoid pointer conversion that violates alignment constraints

block-sha1: put expanded macro parameters in parentheses

2012-07-23T04:13:53Z

't' is currently always a numeric constant, but it can't hurt to prepare for the day that it becomes useful for a caller to pass in a more complex expression. Suggested-by: Linus Torvalds Signed-off-by: Jonathan Nieder Signed-off-by: Junio C Hamano

block-sha1: avoid pointer conversion that violates alignment constraints

2012-07-23T04:11:35Z

With 660231aa (block-sha1: support for architectures with memory alignment restrictions, 2009-08-12), blk_SHA1_Update was modified to access 32-bit chunks of memory one byte at a time on arches that prefer that: #define get_be32(p) ( \ (*((unsigned char *)(p) + 0) << 24) | \ (*((unsigned char *)(p) + 1) << 16) | \ (*((unsigned char *)(p) + 2) << 8) | \ (*((unsigned char *)(p) + 3) << 0) ) The code previously accessed these values by just using htonl(*p). Unfortunately, Michael noticed on an Alpha machine that git was using plain 32-bit reads anyway. As soon as we convert a pointer to int *, the compiler can assume that the object pointed to is correctly aligned as an int (C99 section 6.3.2.3 "pointer conversions" paragraph 7), and gcc takes full advantage by using a single 32-bit load, resulting in a whole bunch of unaligned access traps. So we need to obey the alignment constraints even when only dealing with pointers instead of actual values. Do so by changing the type of 'data' to void *. This patch renames 'data' to 'block' at the same time to make sure all references are updated to reflect the new type. Reported-tested-and-explained-by: Michael Cree Signed-off-by: Jonathan Nieder Acked-by: Linus Torvalds Signed-off-by: Junio C Hamano

msvc: Select the "fast" definition of the {get,put}_be32() macros

2010-06-28T04:59:32Z

On Intel machines, the msvc compiler defines the CPU architecture macros _M_IX86 and _M_X64 (equivalent to __i386__ and __x86_64__ respectively). Use these macros in the pre-processor expression to select the "fast" definition of the {get,put}_be32() macros. Signed-off-by: Ramsay Jones Acked-by: Jonathan Nieder Signed-off-by: Junio C Hamano

msvc: Fix some compiler warnings

2010-06-25T18:04:16Z

In particular, using the normal (or production) compiler warning level (-W3), msvc complains as follows: .../sha1.c(244) : warning C4018: '<' : signed/unsigned mismatch .../sha1.c(270) : warning C4244: 'function' : conversion from \ 'unsigned __int64' to 'unsigned long', possible loss of data .../sha1.c(271) : warning C4244: 'function' : conversion from \ 'unsigned __int64' to 'unsigned long', possible loss of data Note that gcc issues a similar complaint about line 244 when compiling with -Wextra. Signed-off-by: Ramsay Jones Signed-off-by: Junio C Hamano

remove ARM and Mozilla SHA1 implementations

2009-08-18T21:19:40Z

They are both slower than the new BLK_SHA1 implementation, so it is pointless to keep them around. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano

block-sha1: guard gcc extensions with GNUC

2009-08-18T21:18:36Z

With this, the code should now be portable to any C compiler. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano

make sure byte swapping is optimal for git

2009-08-18T21:16:37Z

We rely on ntohl() and htonl() to perform byte swapping in many places. However, some platforms have libraries providing really poor implementations of those which might cause significant performance issues, especially with the block-sha1 code. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano

block-sha1: make the size member first in the context struct

2009-08-18T19:26:01Z

This is a 64-bit value, hence having it first provides a better alignment. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano

block-sha1/sha1.c: silence compiler complaints by casting void * to char *

2009-08-15T02:13:00Z

Some compilers produce errors when arithmetic is attempted on pointers to void. We want computations done on byte addresses, so cast them to char * to work them around. Signed-off-by: Brandon Casey Signed-off-by: Junio C Hamano