strip kernel modules more aggressively: make all global symbols local, rename all symbols in the symbol table to make them compress better

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@30662 3c298f89-4303-0410-b956-a3cf2f4a3e73

rules.mk

@@ -219,9 +219,10 @@ else
     endif
   endif
   RSTRIP:= \
+    export CROSS="$(TARGET_CROSS)"; \
     NM="$(TARGET_CROSS)nm" \
     STRIP="$(STRIP)" \
-    STRIP_KMOD="$(TARGET_CROSS)strip --strip-unneeded -R .comment -R .pdr -R .mdebug.abi32 -R .note.gnu.build-id -R .gnu.attributes -R .reginfo -x" \
+    STRIP_KMOD="$(SCRIPT_DIR)/strip-kmod.sh" \
     $(SCRIPT_DIR)/rstrip.sh
 endif
 

scripts/rstrip.sh

@@ -5,25 +5,6 @@
 # This is free software, licensed under the GNU General Public License v2.
 # See /LICENSE for more information.
 #
-
-find_modparams() {
-	FILE="$1"
-	$NM "$FILE" | awk '
-BEGIN {
-	FS=" "
-}
-($3 ~ /^__module_parm_/) && ($3 !~ /^__module_parm_desc/) {
-	gsub(/__module_parm_/, "", $3)
-	printf "-K " $3 " "
-}
-($2 ~ /r/) && ($3 ~ /__param_/) {
-	gsub(/__param_/, "", $3)
-	printf "-K " $3 " "
-}
-'
-}
-
-
 SELF=${0##*/}
 
 [ -z "$STRIP" ] && {
@@ -46,7 +27,7 @@ find $TARGETS -type f -a -exec file {} \; | \
   while read F S; do
     echo "$SELF: $F:$S"
 	[ "${S}" = "relocatable" ] && {
-		eval "$STRIP_KMOD -w -K '__param*' -K '__mod*' $(find_modparams "$F")$F"
+		eval "$STRIP_KMOD $F"
 	} || {
 		b=$(stat -c '%a' $F)
 		eval "$STRIP $F"

scripts/strip-kmod.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+[ -n "$CROSS" ] || {
+	echo "The variable CROSS must be set to point to the cross-compiler prefix"
+	exit 1
+}
+
+MODULE="$1"
+
+[ "$#" -ne 1 ] && {
+	echo "Usage: $0 <module>"
+	exit 1
+}
+
+${CROSS}objcopy \
+	--strip-unneeded \
+	-R .comment \
+	-R .pdr \
+	-R .mdebug.abi32 \
+	-R .note.gnu.build-id \
+	-R .gnu.attributes \
+	-R .reginfo \
+	-G __this_module \
+	-x "$MODULE" "$MODULE.tmp"
+
+${CROSS}nm "$MODULE.tmp" | awk '
+BEGIN {
+	n = 0
+}
+
+$3 && $2 ~ /[brtd]/ && $3 !~ /\$LC/ {
+	print "--redefine-sym "$3"=_"n;
+	n = n + 1
+}
+' > "$MODULE.tmp1"
+
+${CROSS}objcopy `cat ${MODULE}.tmp1` ${MODULE}.tmp ${MODULE}.out
+mv "${MODULE}.out" "${MODULE}"
+rm -f "${MODULE}".t*