diff --git a/ChangeLog b/ChangeLog
index 29df28d912..545348ebfc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Nov 25 08:48:35 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
+
+	* configure.in: turn on PIE if --enable-shared is not specified.
+
 Fri Nov 25 08:05:07 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* configure.in: add -fstack-protector. It help to protect us from
diff --git a/configure.in b/configure.in
index caef7d6684..30be256903 100644
--- a/configure.in
+++ b/configure.in
@@ -2350,6 +2350,12 @@ AS_CASE("$enable_shared", [yes], [
 	])
 ], [
   LIBRUBYARG_SHARED=
+
+  # enable PIE if possible
+  if test "$GCC" = yes; then
+    RUBY_TRY_CFLAGS(-fPIE, [RUBY_APPEND_OPTION(XCFLAGS, -fPIE)
+    			    RUBY_APPEND_OPTION(XLDFLAGS, -pie)])
+  fi
 ])
 if test "$enable_rpath" = yes; then
     test -z "$LIBRUBY_RPATHFLAGS" || LIBRUBY_RPATHFLAGS="$LIBRUBY_RPATHFLAGS "