A pretty good Git commit

commit fb7d3f32b283a3847e6f151a06794abd14ffd81b
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu Jan 21 11:37:38 2010 -0800

    Remove diff machinery dependency from read-cache
    
    Exal Sibeaz pointed out that some git files are way too big, and that
    add_files_to_cache() brings in all the diff machinery to any git binary
    that needs the basic git SHA1 object operations from read-cache.c. Which
    is pretty much all of them.
    
    It's doubly silly, since add_files_to_cache() is only used by builtin
    programs (add, checkout and commit), so it's fairly easily fixed by just
    moving the thing to builtin-add.c, and avoiding the dependency entirely.
    
    I initially argued to Exal that it would probably be best to try to depend
    on smart compilers and linkers, but after spending some time trying to
    make -ffunction-sections work and giving up, I think Exal was right, and
    the fix is to just do some trivial cleanups like this.
    
    This trivial cleanup results in pretty stunning file size differences.
    The diff machinery really is mostly used by just the builtin programs, and
    you have things like these trivial before-and-after numbers:
    
      -rwxr-xr-x 1 torvalds torvalds 1727420 2010-01-21 10:53 git-hash-object
      -rwxrwxr-x 1 torvalds torvalds  940265 2010-01-21 11:16 git-hash-object
    
    Now, I'm not saying that 940kB is good either, but that's mostly all the
    debug information - you can see the real code with 'size':
    
       text        data     bss     dec     hex filename
     418675        3920  127408  550003   86473 git-hash-object (before)
     230650        2288  111728  344666   5425a git-hash-object (after)
    
    ie we have a nice 24% size reduction from this trivial cleanup.
    
    It's not just that one file either. I get:
    
        [torvalds@nehalem git]$ du -s /home/torvalds/libexec/git-core
        45640   /home/torvalds/libexec/git-core (before)
        33508   /home/torvalds/libexec/git-core (after)
    
    so we're talking 12MB of diskspace here.
    
    (Of course, stripping all the binaries brings the 33MB down to 9MB, so the
    whole debug information thing is still the bulk of it all, but that's a
    separate issue entirely)
    
    Now, I'm sure there are other things we should do, and changing our
    compiler flags from -O2 to -Os would bring the text size down by an
    additional almost 20%, but this thing Exal pointed out seems to be some
    good low-hanging fruit.

    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Junio C Hamano <gitster@pobox.com>

:100644 100644 cb6e590... 2705f8d... M  builtin-add.c
:100644 100644 edd9959... 79938bf... M  read-cache.c