#!/bin/bash

KERNEL_VER=3.10-rc6
D=drivers/gpu/drm/radeon

#
# optional: comment this out to use curl instead of git clone
#
#KERNEL_FROM_GIT=1

if [ ! -d linux ]; then
	if [ ${KERNEL_FROM_GIT:-0} -ne 0 ]; then
		echo "using git to get kernel sources"
		git clone http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git || exit 1
		( cd linux && git checkout v${KERNEL_VER} ) || exit 1
	else
		echo "using tar.xz kernel sources"
		if ! which xz >/dev/null 2>&1; then
			echo "cannot find xz:"
			which xz
			exit 1
		fi
		[ -f linux-${KERNEL_VER}.tar.xz ] || curl -O https://www.kernel.org/pub/linux/kernel/v3.x/testing/linux-${KERNEL_VER}.tar.xz || exit 1
		xz -dc linux-${KERNEL_VER}.tar.xz | tar xf - || exit 1
		mv linux-${KERNEL_VER} linux || exit 1
	fi
	rm -f linux/tags
fi
if [ ! -f avert-func-name-collision.patch ]; then
	#
	# because linux/drivers/gpu/drm/radeon/radeon_drv.c defines static int __init radeon_init(void) also
	# change the name of the #define
	#
	cat <<EOF >avert-func-name-collision.patch
--- linux/drivers/gpu/drm/radeon/radeon.h	2013-06-20 16:22:44.000000000 -0600
+++ linux/drivers/gpu/drm/radeon/radeon.h	2013-06-20 16:22:55.000000000 -0600
@@ -1873,8 +1873,8 @@
 /*
  * ASICs macro.
  */
-#define radeon_init(rdev) (rdev)->asic->init((rdev))
-#define radeon_fini(rdev) (rdev)->asic->fini((rdev))
+#define radeon_asic_p_init(rdev) (rdev)->asic->init((rdev))
+#define radeon_asic_p_fini(rdev) (rdev)->asic->fini((rdev))
 #define radeon_resume(rdev) (rdev)->asic->resume((rdev))
 #define radeon_suspend(rdev) (rdev)->asic->suspend((rdev))
 #define radeon_cs_parse(rdev, r, p) (rdev)->asic->ring[(r)].cs_parse((p))
--- linux/drivers/gpu/drm/radeon/radeon_device.c	2013-06-20 16:24:59.000000000 -0600
+++ linux/drivers/gpu/drm/radeon/radeon_device.c	2013-06-20 16:23:27.000000000 -0600
@@ -1176,7 +1176,7 @@
 	vga_client_register(rdev->pdev, rdev, NULL, radeon_vga_set_decode);
 	vga_switcheroo_register_client(rdev->pdev, &radeon_switcheroo_ops);
 
-	r = radeon_init(rdev);
+	r = radeon_asic_p_init(rdev);
 	if (r)
 		return r;
 
@@ -1194,9 +1194,9 @@
 		 * with fallback to PCI or PCIE GART
 		 */
 		radeon_asic_reset(rdev);
-		radeon_fini(rdev);
+		radeon_asic_p_fini(rdev);
 		radeon_agp_disable(rdev);
-		r = radeon_init(rdev);
+		r = radeon_asic_p_init(rdev);
 		if (r)
 			return r;
 	}
@@ -1228,7 +1228,7 @@
 	rdev->shutdown = true;
 	/* evict vram memory */
 	radeon_bo_evict_vram(rdev);
-	radeon_fini(rdev);
+	radeon_asic_p_fini(rdev);
 	vga_switcheroo_unregister_client(rdev->pdev);
 	vga_client_register(rdev->pdev, NULL, NULL, NULL);
 	if (rdev->rio_mem)
EOF
	patch -p0 -i avert-func-name-collision.patch
	rm -f linux/tags
fi
if [ ! -f linux/tags ]; then
	echo "ctags -R linux"
	( cd linux && ctags -R ) || exit 1
	rm -f linux/"$D"/tags
fi
if [ ! -f linux/"$D"/tags ]; then
	echo "filter only $D/tags"
	AWK="`echo \"$D\" | awk '{gsub("/","\\\\/");print}'`"
	( cd linux && awk "BEGIN{FS=\"\\t\"}
		{
			if (\$2 ~ /^${AWK}/) print
		}" tags > $D/tags ) || exit 1
fi

whitelist_ops() {
	#
	# expand_whitelist will not find ops structures
	# in reality, there is just one that must be manually selected: 'struct radeon_asic'
	# and only one member needed for coreboot: .init
	# this also pulls in .hpd.init (HPD = hot plug detect) because it is not smart enough not to
	#
	# static struct radeon_asic trinity_asic = {
	#     .init = &cayman_init,
	#     .fini = &cayman_fini,
	#     ...
	#
	(
		echo "awk 'BEGIN{FS=\"\\t\";"
		awk '{
			if (x) {
				if (match($0, "^[[:space:]]*\\.init[[:space:]]*=[[:space:]]&"))
					print "a[\"" gensub(",$", "", "", substr($0, RSTART+RLENGTH)) "\"]=1;";
				c+=gsub("{","");
				c-=gsub("}","");
				if (!c) x=0
			};
			if ($0 ~ "^static struct radeon_asic.*=.*{") {x=1;c=gsub("{","");}
		}' "$D"/radeon_asic.c
		echo "}{n=3;while (!match(\$n, \";\\\"\$\") && n < NF) n++;n++;if (\$n==\"f\" && \$1 in a) print}' \"$D\"/tags"
	) > "$D"/whitelist.sh || exit 1
	( cat "$D"/whitelist && . "$D"/whitelist.sh ) | sort -u > "$D"/whitelist.out
	rm -f "$D"/whitelist.sh
	mv "$D"/whitelist.out "$D"/whitelist
}

expand_whitelist() {
	#
	# 1. output the function bodies of all functions in the whitelist
	# 2. look up every C identifier in that text
	# 3. any C identifier found in tags (ctags output file) with $4=="f" is a function
	# 4. replace the whitelist with the new list
	#

	# step 1: function bodies
	awk 'BEGIN{FS="\t";print "#!/bin/bash"}{
			sub("/\\^","\"",$3);
			sub("\\$/;\"$","\"",$3);
			print "awk '"'"'{if (x) {n=$0;c+=gsub(\"{\",\"\");c-=gsub(\"}\",\"\");print n;if (!c) x=0};"
			print "    if ($0 == " $3 ") {x=1;c=0}}'"'"' " $2
		}' "$D"/whitelist > "$D"/whitelist.sh
	. "$D"/whitelist.sh > "$D"/whitelist.out || exit 1

	# step 2: C identifiers
	awk '{
			s=$0;
			while (1) {
				gsub("\"[^\"]*\"","",s);
				if (!match(s, "[_A-Za-z][0-9_A-Za-z]*")) break;
				print "a[\"" substr(s,RSTART,RLENGTH) "\"]=1;";
				s=substr(s,RSTART+RLENGTH);
			}
		}' "$D"/whitelist.out | sort -u > "$D"/whitelist.awk || exit 1

	# step 3 and 4: functions
	(
		echo "awk 'BEGIN{FS=\"\\t\";"
		cat "$D"/whitelist.awk
		echo "}{n=3;while (!match(\$n, \";\\\"\$\") && n < NF) n++;n++;if (\$n==\"f\" && \$1 in a) print}' \"$D\"/tags"
	) > "$D"/whitelist.sh
	rm -f "$D"/whitelist.awk

	. "$D"/whitelist.sh > "$D"/whitelist.out || exit 1
	cat "$D"/whitelist "$D"/whitelist.out | sort -u > "$D"/whitelist.sh || exit 1
	mv "$D"/whitelist.sh "$D"/whitelist || exit 1
	rm -f "$D"/whitelist.out
}

if [ ! -f linux/"$D"/whitelist ]; then
	echo "expand whitelist"
	(
	cd linux || exit 1
	grep '^\(radeon_driver_load_kms\|radeon_driver_open_kms\)' "$D"/tags > "$D"/whitelist || exit 1
	whitelist_ops

	c=0
	while true; do
		N="`awk 'END{print NR}' \"$D\"/whitelist`"
		echo -e "\e[A\e[Kexpand whitelist: $N"
		expand_whitelist
		M="`awk 'END{print NR}' \"$D\"/whitelist`"
		[ $M -eq $N ] && break
	done
	) || exit 1
	rm -f unused_funcs.spatch
fi

if [ ! -f unused_funcs.spatch ]; then
	echo "> unused_funcs.spatch"
	awk 'BEGIN{
			print "@whitelist@";
			print "@@";
			s = "(";
		}
		{
			print s;
			print $1 "(...) {...}";
			s = "|";
		}
		END{
			print ")";
			print "";
			print "@remove_other_funcs depends on !whitelist@";
			print "identifier funcname";
			print "@@";
			print "<...";
			print "-funcname(...) {...}";
			print "...>";
		}' linux/"$D"/whitelist > unused_funcs.spatch
fi