linux/scripts/objdiff
Jason Cooper 79192ca8eb scripts: objdiff: detect object code changes between two commits
objdiff is useful when doing large code cleanups.  For example, when
removing checkpatch warnings and errors from new drivers in the staging
tree.

objdiff can be used in conjunction with a git rebase to confirm that
each commit made no changes to the resulting object code.  It has the
same return values as diff(1).

This was written specifically to support adding the skein and threefish
cryto drivers to the staging tree.  I needed a programmatic way to
confirm that commits changing >90% of the lines didn't inadvertently
change the code.

Temporary files (objdump output) are stored in

  /path/to/linux/.tmp_objdiff

'make mrproper' will remove this directory.

Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>
2014-04-08 16:41:44 +02:00

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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
GIT_DIR="`git rev-parse --git-dir`"
if [ -d "$GIT_DIR" ]; then
TMPD="${GIT_DIR%git}tmp_objdiff"
[ -d "$TMPD" ] || mkdir "$TMPD"
else
echo "ERROR: git directory not found."
exit 1
fi
usage() {
echo "Usage: $0 <command> <args>"
echo " record <list of object files>"
echo " diff <commitA> <commitB>"
echo " clean all | <commit>"
exit 1
}
dorecord() {
[ $# -eq 0 ] && usage
FILES="$*"
CMT="`git rev-parse --short HEAD`"
OBJDUMP="${CROSS_COMPILE}objdump"
OBJDIFFD="$TMPD/$CMT"
[ ! -d "$OBJDIFFD" ] && mkdir -p "$OBJDIFFD"
for f in $FILES; do
dn="${f%/*}"
bn="${f##*/}"
[ ! -d "$OBJDIFFD/$dn" ] && mkdir -p "$OBJDIFFD/$dn"
# remove addresses for a more clear diff
# http://dummdida.tumblr.com/post/60924060451/binary-diff-between-libc-from-scientificlinux-and
$OBJDUMP -D "$f" | sed "s/^[[:space:]]\+[0-9a-f]\+//" \
>"$OBJDIFFD/$dn/$bn"
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 "ERROR: $SRCD doesn't exist"
exit 1
fi
if [ ! -d "$DSTD" ]; then
echo "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 "$CMT not found"
fi
fi
}
[ $# -eq 0 ] && usage
case "$1" in
record)
shift
dorecord $*
;;
diff)
shift
dodiff $*
;;
clean)
shift
doclean $*
;;
*)
echo "Unrecognized command '$1'"
exit 1
;;
esac