xref: /linux/scripts/objdiff (revision 18165efa8203a34d82f60a1831ea290e7304c654)
1#!/bin/bash
2
3# objdiff - a small script for validating that a commit or series of commits
4# didn't change object code.
5#
6# Copyright 2014, Jason Cooper <jason@lakedaemon.net>
7#
8# Licensed under the terms of the GNU GPL version 2
9
10# usage example:
11#
12# $ git checkout COMMIT_A
13# $ <your fancy build command here>
14# $ ./scripts/objdiff record path/to/*.o
15#
16# $ git checkout COMMIT_B
17# $ <your fancy build command here>
18# $ ./scripts/objdiff record path/to/*.o
19#
20# $ ./scripts/objdiff diff COMMIT_A COMMIT_B
21# $
22
23# And to clean up (everything is in .tmp_objdiff/*)
24# $ ./scripts/objdiff clean all
25#
26# Note: 'make mrproper' will also remove .tmp_objdiff
27
28SRCTREE=$(cd $(git rev-parse --show-toplevel 2>/dev/null); pwd)
29
30if [ -z "$SRCTREE" ]; then
31	echo >&2 "ERROR: Not a git repository."
32	exit 1
33fi
34
35TMPD=$SRCTREE/.tmp_objdiff
36
37usage() {
38	echo >&2 "Usage: $0 <command> <args>"
39	echo >&2 "  record    <list of object files>"
40	echo >&2 "  diff      <commitA> <commitB>"
41	echo >&2 "  clean     all | <commit>"
42	exit 1
43}
44
45get_output_dir() {
46	dir=${1%/*}
47
48	if [ "$dir" = "$1" ]; then
49		dir=.
50	fi
51
52	dir=$(cd $dir; pwd)
53
54	echo $TMPD/$CMT${dir#$SRCTREE}
55}
56
57dorecord() {
58	[ $# -eq 0 ] && usage
59
60	FILES="$*"
61
62	CMT="`git rev-parse --short HEAD`"
63
64	OBJDUMP="${CROSS_COMPILE}objdump"
65
66	for f in $FILES; do
67		dir=$(get_output_dir $f)
68		bn="${f##*/}"
69
70		[ ! -d "$dir" ] && mkdir -p $dir
71
72		# remove addresses for a more clear diff
73		# http://dummdida.tumblr.com/post/60924060451/binary-diff-between-libc-from-scientificlinux-and
74		$OBJDUMP -D $f | sed "s/^[[:space:]]\+[0-9a-f]\+//" > $dir/$bn
75	done
76}
77
78dodiff() {
79	[ $# -ne 2 ] && [ $# -ne 0 ] && usage
80
81	if [ $# -eq 0 ]; then
82		SRC="`git rev-parse --short HEAD^`"
83		DST="`git rev-parse --short HEAD`"
84	else
85		SRC="`git rev-parse --short $1`"
86		DST="`git rev-parse --short $2`"
87	fi
88
89	DIFF="`which colordiff`"
90
91	if [ ${#DIFF} -eq 0 ] || [ ! -x "$DIFF" ]; then
92		DIFF="`which diff`"
93	fi
94
95	SRCD="$TMPD/$SRC"
96	DSTD="$TMPD/$DST"
97
98	if [ ! -d "$SRCD" ]; then
99		echo >&2 "ERROR: $SRCD doesn't exist"
100		exit 1
101	fi
102
103	if [ ! -d "$DSTD" ]; then
104		echo >&2 "ERROR: $DSTD doesn't exist"
105		exit 1
106	fi
107
108	$DIFF -Nurd $SRCD $DSTD
109}
110
111doclean() {
112	[ $# -eq 0 ] && usage
113	[ $# -gt 1 ] && usage
114
115	if [ "x$1" = "xall" ]; then
116		rm -rf $TMPD/*
117	else
118		CMT="`git rev-parse --short $1`"
119
120		if [ -d "$TMPD/$CMT" ]; then
121			rm -rf $TMPD/$CMT
122		else
123			echo >&2 "$CMT not found"
124		fi
125	fi
126}
127
128[ $# -eq 0 ] &&	usage
129
130case "$1" in
131	record)
132		shift
133		dorecord $*
134		;;
135	diff)
136		shift
137		dodiff $*
138		;;
139	clean)
140		shift
141		doclean $*
142		;;
143	*)
144		echo >&2 "Unrecognized command '$1'"
145		exit 1
146		;;
147esac
148