#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-only

# 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>
#

# 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ドル <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ドル" ]; then
dir=.
	fi

dir=$(cd $dir; pwd)

	echo $TMPD/$CMT${dir#$SRCTREE}
}

do_objdump() {
	dir=$(get_output_dir 1ドル)
	base=${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ドル -R __bug_table -R .note -R .comment -o $stripped
	$OBJDUMP -D $stripped | sed -e "s/^[[:space:]]\+[0-9a-f]\+//" -e "s:^$stripped:1ドル:" > $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ドル`"
		DST="`git rev-parse --short 2ドル`"
	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 [ "x1ドル" = "xall" ]; then
rm -rf $TMPD/*
	else
CMT="`git rev-parse --short 1ドル`"

		if [ -d "$TMPD/$CMT" ]; then
rm -rf $TMPD/$CMT
		else
echo >&2 "$CMT not found"
		fi
	fi
}

[ $# -eq 0 ] &&	usage

case "1ドル" in
record)
		shift
dorecord $*
		;;
	diff)
		shift
dodiff $*
		;;
	clean)
		shift
doclean $*
		;;
	*)
		echo >&2 "Unrecognized command '1ドル'"
		exit 1
		;;
esac