scripts: objdiff: detect object code changes between two commits

# Directories & files removed with 'make mrproper'

MRPROPER_DIRS  += include/config usr/include include/generated          \

                  arch/*/include/generated

                  arch/*/include/generated .tmp_objdiff

MRPROPER_FILES += .config .config.old .version .old_version $(version_h) \

		  Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \

		  signing_key.priv signing_key.x509 x509.genkey		\

#!/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