source: MondoRescue/branches/3.2/mindi-busybox/scripts/mkdiff_obj

#!/bin/sh

usage() {
    echo "Usage: ${0##*/} DIR1 DIR2"
    echo
    echo "Compares all object files recursivelty found in DIR1 and DIR2."
    echo "Prints diff of their disassembly."
    echo
    exit $1
}

filter() {
    # sed removes " address: " prefixes which mess up diff
    sed $'s/^\\(\t*\\)[ ]*[0-9a-f][0-9a-f]*:[ \t]*/\\1/' \
    | sed 's/__GI_//g'
}

test -d "$1" || usage 1
test -d "$2" || usage 1

{
    (
        cd "$1" || exit 1
        find -name '*.o' # -o -name '*.os' # -o -name '*.so'
    )
    (
        cd "$2" || exit 1
        find -name '*.o' # -o -name '*.os' # -o -name '*.so'
    )
} | sed 's:^\./::' | sort | uniq | \
(
while IFS='' read -r oname; do
    if ! test -f "$1/$oname"; then
        echo "Only $2/$oname"
        continue
    fi
    if ! test -f "$2/$oname"; then
        echo "Only $1/$oname"
        continue
    fi
    diff -q -- "$1/$oname" "$2/$oname" >/dev/null && continue
    (cd "$1" && { size "$oname"; objdump -dr "$oname" | filter; } >"$oname.disasm")
    (cd "$2" && { size "$oname"; objdump -dr "$oname" | filter; } >"$oname.disasm")
    diff -u -- "$1/$oname.disasm" "$2/$oname.disasm"
done
)