linux-hardened/scripts/objdiff
Stephen Boyd 65ba6fa439 scripts: objdiff: Ignore debug info when comparing
If the kernel is configured to be built with debug symbols, or
has bug tables, comparing files may not work if line numbers
change. This makes comparing object files with these options
harder to do. Let's strip out the debug info and drop the
__bug_table here so that we don't see false positives. There may
be other things to drop later, and it may be architecture
specific, but this works for me with my ARM64 build.

Signed-off-by: Stephen Boyd <stephen.boyd@linaro.org>
Reviewed-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-03-11 11:13:38 +09:00

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#!/bin/bash
# objdiff - a small script for validating that a commit or series of commits
# didn't change object code.
#
# Copyright 2014, Jason Cooper <jason@lakedaemon.net>
#
# Licensed under the terms of the GNU GPL version 2
# usage example:
#
# $ git checkout COMMIT_A
# $ <your fancy build command here>
# $ ./scripts/objdiff record path/to/*.o
#
# $ git checkout COMMIT_B
# $ <your fancy build command here>
# $ ./scripts/objdiff record path/to/*.o
#
# $ ./scripts/objdiff diff COMMIT_A COMMIT_B
# $
# And to clean up (everything is in .tmp_objdiff/*)
# $ ./scripts/objdiff clean all
#
# Note: 'make mrproper' will also remove .tmp_objdiff
SRCTREE=$(cd $(git rev-parse --show-toplevel 2>/dev/null); pwd)
if [ -z "$SRCTREE" ]; then
echo >&2 "ERROR: Not a git repository."
exit 1
fi
TMPD=$SRCTREE/.tmp_objdiff
usage() {
echo >&2 "Usage: $0 <command> <args>"
echo >&2 " record <list of object files or directories>"
echo >&2 " diff <commitA> <commitB>"
echo >&2 " clean all | <commit>"
exit 1
}
get_output_dir() {
dir=${1%/*}
if [ "$dir" = "$1" ]; then
dir=.
fi
dir=$(cd $dir; pwd)
echo $TMPD/$CMT${dir#$SRCTREE}
}
do_objdump() {
dir=$(get_output_dir $1)
base=${1##*/}
stripped=$dir/${base%.o}.stripped
dis=$dir/${base%.o}.dis
[ ! -d "$dir" ] && mkdir -p $dir
# remove addresses for a cleaner diff
# http://dummdida.tumblr.com/post/60924060451/binary-diff-between-libc-from-scientificlinux-and
$STRIP -g $1 -R __bug_table -R .note -R .comment -o $stripped
$OBJDUMP -D $stripped | sed -e "s/^[[:space:]]\+[0-9a-f]\+//" -e "s:^$stripped:$1:" > $dis
}
dorecord() {
[ $# -eq 0 ] && usage
FILES="$*"
CMT="`git rev-parse --short HEAD`"
STRIP="${CROSS_COMPILE}strip"
OBJDUMP="${CROSS_COMPILE}objdump"
for d in $FILES; do
if [ -d "$d" ]; then
for f in $(find $d -name '*.o')
do
do_objdump $f
done
else
do_objdump $d
fi
done
}
dodiff() {
[ $# -ne 2 ] && [ $# -ne 0 ] && usage
if [ $# -eq 0 ]; then
SRC="`git rev-parse --short HEAD^`"
DST="`git rev-parse --short HEAD`"
else
SRC="`git rev-parse --short $1`"
DST="`git rev-parse --short $2`"
fi
DIFF="`which colordiff`"
if [ ${#DIFF} -eq 0 ] || [ ! -x "$DIFF" ]; then
DIFF="`which diff`"
fi
SRCD="$TMPD/$SRC"
DSTD="$TMPD/$DST"
if [ ! -d "$SRCD" ]; then
echo >&2 "ERROR: $SRCD doesn't exist"
exit 1
fi
if [ ! -d "$DSTD" ]; then
echo >&2 "ERROR: $DSTD doesn't exist"
exit 1
fi
$DIFF -Nurd $SRCD $DSTD
}
doclean() {
[ $# -eq 0 ] && usage
[ $# -gt 1 ] && usage
if [ "x$1" = "xall" ]; then
rm -rf $TMPD/*
else
CMT="`git rev-parse --short $1`"
if [ -d "$TMPD/$CMT" ]; then
rm -rf $TMPD/$CMT
else
echo >&2 "$CMT not found"
fi
fi
}
[ $# -eq 0 ] && usage
case "$1" in
record)
shift
dorecord $*
;;
diff)
shift
dodiff $*
;;
clean)
shift
doclean $*
;;
*)
echo >&2 "Unrecognized command '$1'"
exit 1
;;
esac