#!/usr/bin/env awk
#
# List dependencies in Makefile input,
# ignore a set of default targets and 1:1 dependencies
# and generate dot graph output

BEGIN {
	FS = " *: *"

	ignore["all"] = 1
	ignore["configure"] = 1
	ignore["Makefile"] = 1
	ignore["install"] = 1
	ignore["uninstall"] = 1
	ignore["clean"] = 1
	ignore["distclean"] = 1
	ignore["realclean"] = 1
	ignore["mostlyclean"] = 1
	ignore["superclean"] = 1
	ignore["mmhdist"] = 1
	ignore["lint"] = 1

	print "digraph foo {"
}

/^\t/ {
	next
}

$1 ~ /^[a-zA-Z_]+$/ {
	if ($1 in ignore) {
		next
	}
	split($2, dep, /[ \t]+/)
	for (i in dep) {
		if (dep[i] ~ /^\$/) {
			continue
		}
		if (dep[i] ~ "^"$1"\\.(o|sh)$") {
			continue
		}
		sub(/\.o$/, ".c", dep[i]);
		print "\t\"" dep[i] "\" [shape=box];"
		print "\t\"" dep[i] "\" -> \"" $1 "\";"
	}
	print ""
}

END {
	print "}"
}