#!/bin/sh
set -e

usage() {
    argv0=`basename $0`

    cat >&2 << END
Usage:
For comparing files created my cairo-perf:

	$argv0 old.perf new.perf

For comparing (cached) performance of revisions:

	$argv0 [OPTIONS] <revision> [-- cairo-perf options]
	$argv0 [OPTIONS] <rev1> <rev2> [-- cairo-perf-options]

If given a single revision, compares its results to that of its
(first-parent) predecessor. Otherwise compares the two given revisions.
The revisions can be any revision accepted by git. For example:

	$argv0 HEAD		# Show impact of latest commit
	$argv0 1.2.0 1.2.4	# Compare performance of 1.2.0 to 1.2.4

Options:

-f, --force
	Forces cairo-perf-diff to re-run performance tests
	even if cached performance data is available.

-h, --html
	With this option performance changes are summarized
	as HTML table.

-t, --trace
	Compare performance using trace replays instead of
	microbenchmarks.

Additional options can be passed the child cairo-perf process
by separating them with a double hyphen (--). For example, to
examine what the impact of the latest change is on the stroke
test you might use:

	$argv0 HEAD -- stroke

The performance results are cached in .perf next to the .git directory.

Set CAIRO_AUTOGEN_OPTIONS to pass options to autogen for both
builds.
END

    exit 1
}

benchmark="cairo-perf-micro"

# First, pull off any known options
while true; do
    case $1 in
        -f|--force) force_cairo_perf="true";;
        -h|--html) html_output="$2"; shift ;;
        -t|--trace) benchmark="cairo-perf-trace";;
        *) break;;
    esac

    shift
done

# Then if anything is left that still looks like an option, (begins
# with a dash), give usage to catch --help or any other -garbage
if [ $# -eq 0 ] || [ "`echo "$1" | sed 's/^-//'`" != "$1" ]; then
    usage
fi

# Finally, pick up the actual revision arguments
if [ $# -eq 1 ] || [ "$2" = "--" ]; then
    old="$1^"
    new="$1"
    shift 1
else
    old="$1"
    new="$2"
    shift 2
fi

# And post-finally, pass anything after -- on to cairo-perf
CAIRO_PERF_OPTIONS="-r -i 10"
if [ $# -gt 0 ]; then
    if [ "$1" = "--" ]; then
	shift 1
	CAIRO_PERF_OPTIONS="$CAIRO_PERF_OPTIONS $@"
    else
	usage
    fi
fi

git_setup() {
    SUBDIRECTORY_OK='Yes'
    . "$(git --exec-path)/git-sh-setup"
    CAIRO_DIR=`dirname $GIT_DIR`
    if [ "$CAIRO_DIR" = "." ]; then
	CAIRO_DIR=`pwd`
    fi
    CAIRO_PERF_DIR=$CAIRO_DIR/.perf
}

rev2sha() {
    rev=$1
    git rev-parse --verify $rev || ( echo "Cannot resolve $rev as a git object" && exit 1 )
}

cpu_count() {
    test -f /proc/cpuinfo &&
    grep -c '^processor[[:blank:]]\+:' /proc/cpuinfo ||
    echo 1
}

# We cache performance output based on a two-part name capturing the
# current performance test suite and the library being tested. We
# capture these as the tree object of the perf directory in HEAD and
# the tree object of the src directory of the revision being tested.
#
# This way, whenever the performance suite is updated, cached output
# from old versions of the suite are automatically invalidated. Also,
# if a commit just changes things outside of the src tree, (say it
# changes the "test" test suite, or README or configure.in, or
# whatever), cairo-perf-diff will be smart enough to still use cached
# results from a run with an equivalent src tree.
rev2perf() {
    rev=$1
    sha=`rev2sha $rev`
    src_tree_sha=`rev2sha $rev:src`
    perf_tree_sha=`rev2sha HEAD:perf`
    script_tree_sha=`rev2sha HEAD:util/cairo-script`
    echo "$CAIRO_PERF_DIR/${sha}-${perf_tree_sha}-${script_tree_sha}-${src_tree_sha}.perf"
}
rev2perf_glob() {
    rev=$1
    src_tree_sha=`rev2sha $rev:src`
    perf_tree_sha=`rev2sha HEAD:perf`
    script_tree_sha=`rev2sha HEAD:util/cairo-script`
    echo "$CAIRO_PERF_DIR/*-${perf_tree_sha}-${script_tree_sha}-${src_tree_sha}.perf"
}

build() {
    build_dir=$1
    sha=$2

    if [ ! -d $build_dir ]; then
	git clone -s $CAIRO_DIR $build_dir
	(cd $build_dir; git checkout -b tmp-cairo-perf-diff $sha)
    fi
    cd $build_dir

    git checkout tmp-cairo-perf-diff
    git reset --hard $sha

    if [ -z "$MAKEFLAGS" ]; then
	CPU_COUNT=`cpu_count`
        export MAKEFLAGS="-j`expr $CPU_COUNT + 1`"
    fi

    if [ ! -e Makefile ]; then
	./autogen.sh $CAIRO_AUTOGEN_OPTIONS
    fi

    for file in $boilerplate_files; do
	rsync $CAIRO_DIR/$file boilerplate
    done
    for file in $perf_files; do
	rsync $CAIRO_DIR/$file perf
    done
    for file in $script_files; do
	rsync $CAIRO_DIR/$file util/cairo-script
    done

    make || (rm config.cache && make)
    (cd boilerplate && make libcairoboilerplate.la)

    cd perf
    make ${benchmark}
}

# Usage: run_cairo_perf_if_not_cached <rev> <suffix>
# The <rev> argument must be a valid git ref-spec that can
# be resolved to a commit. The suffix is just something
# unique so that build directories can be separated for
# multiple calls to this function.
run_cairo_perf_if_not_cached() {
    rev=$1
    build_dir="build-$2"

    owd=`pwd`
    sha=`rev2sha $rev`
    perf=`rev2perf $rev`
    glob=`rev2perf_glob $rev`
    if [ -e $glob ] && [ "$force_cairo_perf" != "true" ]; 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_DIR
    boilerplate_files=`git ls-tree --name-only HEAD boilerplate/*`
    perf_files=`git ls-tree --name-only HEAD perf/*`
    script_files=`git ls-tree --name-only HEAD util/cairo-script/*`
    cd $CAIRO_PERF_DIR

    build $build_dir $sha || {
	rm -rf $build_dir
	build $build_dir $sha || exit 1
    }

    echo "Running \"cairo-perf $CAIRO_PERF_OPTIONS\" against $rev. Results will be cached in:"
    { ./$benchmark $CAIRO_PERF_OPTIONS || echo "*** Performance test crashed"; } >> $perf

    cd $owd
}

git_setup

if [ -e ./cairo-perf-diff-files ]; then
	bindir="."
else
	bindir=$CAIRO_DIR/perf

	# Build cairo-perf-diff-files if not available
	if [ ! -e $bindir/cairo-perf-diff-files ]; then
	    echo "Building cairo-perf-diff-files"
	    if [ "x$OS" = "xWindows_NT" ]; then
		make -f Makefile.win32 -C $bindir cairo-perf-diff-files CFG=debug
	    else
		make -C $bindir cairo-perf-diff-files
	    fi
	fi
fi

if [ ! -e $old ]; then
    run_cairo_perf_if_not_cached $old old
    old=`rev2perf $old`
fi

if [ ! -e $new ]; then
    run_cairo_perf_if_not_cached $new new
    new=`rev2perf $new`
fi

if [ -z "$html_output" ]; then
    $bindir/cairo-perf-diff-files $old $new
else
    $bindir/cairo-perf-diff-files $old $new |
    $CAIRO_DIR/perf/make-html.py > $html_output
fi