cairo/perf/cairo-perf-diff

#!/bin/sh
set -e

usage() {
    argv0=$(basename $0)
    echo "Usage:" >&2
    echo "For comparing files created my cairo-perf:" >&2
    echo "" >&2
    echo "	$argv0 old.perf new.perf" >&2
    echo "" >&2
    echo "For comparing (cached) performance of revisions:" >&2
    echo "" >&2
    echo "	$argv0 <revision>" >&2
    echo "	$argv0 <rev1> <rev2>" >&2
    echo "" >&2
    echo "If given a single revision, compares its results to that of its" >&2
    echo "(first-parent) predecessor. Otherwise compares the two given revisions." >&2
    echo "The revisions can be any revision accepted by git. For example:" >&2
    echo "" >&2
    echo "	$argv0 HEAD		# Show impact of latest commit" >&2
    echo "	$argv0 1.2.0 1.2.4	# Compare performance of 1.2.0 to 1.2.4" >&2
    echo "" >&2
    echo "The performance results are cached in .perf next to the .git directory." >&2
    exit 1
}

if [ $# -eq 1 ]; then
    old="$1^"
    new="$1"
elif [ $# -eq 2 ]; then
    old="$1"
    new="$2"
else
    usage
fi

git_setup() {
    SUBDIRECTORY_OK='Yes'
    . git-sh-setup
    CAIRO_DIR=$(dirname $GIT_DIR)
    CAIRO_PERF_DIR=$CAIRO_DIR/.perf
}

rev2sha() {
    rev=$1
    git rev-parse --verify $rev || ( echo "Cannot reolve $rev to a revision" && exit 1 )
}

rev2perf() {
    rev=$1
    sha=$(rev2sha $rev)
    echo "$CAIRO_PERF_DIR/$sha.perf"
}

# Usage: run_cairo_perf_if_not_cached <rev>
run_cairo_perf_if_not_cached() {
    rev=$1

    owd=$(pwd)
    sha=$(rev2sha $rev)
    perf=$(rev2perf $rev)
    if [ -e $perf ]; then
	return 0
    fi
    if [ ! -d $CAIRO_PERF_DIR ]; then
	echo "Creating new perf cache in $CAIRO_PERF_DIR"
	mkdir $CAIRO_PERF_DIR
    fi
    cd $CAIRO_PERF_DIR

    # XXX: OK, The symlink stuff here is really evil. What we really
    # want is some sort of git-mirror as has been proposed before.

    if [ ! -d build ]; then
	mkdir build
	GIT_DIR=build/.git git init-db
	rm -rf build/.git/objects
	ln -s $GIT_DIR/objects build/.git/objects
	rm -rf build/.git/refs
	ln -s $GIT_DIR/refs build/.git/refs
	cp $GIT_DIR/HEAD build/.git/HEAD
	(cd build; git reset --hard; CFLAGS="-O2" ./autogen.sh)
    fi
    cd build

    # XXX: This is painful too. Maybe using "git-branch -f" would be easier here
    git checkout -b tmp-cairo-perf-diff $sha >/dev/null 2>&1 || (git checkout tmp-cairo-perf-diff && git reset --hard $sha)
    git reset --hard
    make CFLAGS="-O2" || (rm config.cache && make CFLAGS="-O2")
    LD_LIBRARY_PATH=$CAIRO_PERF_DIR/build/src/.libs $CAIRO_DIR/perf/.libs/cairo-perf > $perf
    cd $owd
}

if [ ! -e $old ]; then
    git_setup
    run_cairo_perf_if_not_cached $old
    old=$(rev2perf $old)
fi

if [ ! -e $new ]; then
    git_setup
    run_cairo_perf_if_not_cached $new
    new=$(rev2perf $new)
fi

cairo-perf-diff-files $old $new