diff --git a/ChangeLog b/ChangeLog
index ae27ddd3d2..276ea0187b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jun 24 12:47:05 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* include/ruby/intern.h (rb_strlen_lit): new macro to get the
+	  length of a string literal, borrowed from mruby/mruby@e4afd53.
+
 Wed Jun 24 12:21:16 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* re.c: Update documentation for Regexp class.
diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 9e26c8b4f3..56865f3109 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -877,10 +877,15 @@ VALUE rb_sym_all_symbols(void);
 #define rb_str_buf_cat rb_str_cat
 #define rb_str_buf_cat2 rb_str_cat_cstr
 #define rb_str_cat2 rb_str_cat_cstr
-#define rb_str_new_literal(str) rb_str_new_static((str), sizeof(str)-1)
-#define rb_usascii_str_new_literal(str) rb_usascii_str_new_static((str), sizeof(str)-1)
-#define rb_utf8_str_new_literal(str) rb_utf8_str_new_static((str), sizeof(str)-1)
-#define rb_enc_str_new_literal(str, enc) rb_enc_str_new_static((str), sizeof(str)-1, (enc))
+#define rb_strlen_lit(str) (sizeof(str "") - 1)
+#define rb_str_new_lit(str) rb_str_new_static((str), rb_strlen_lit(str))
+#define rb_usascii_str_new_lit(str) rb_usascii_str_new_static((str), rb_strlen_lit(str))
+#define rb_utf8_str_new_lit(str) rb_utf8_str_new_static((str), rb_strlen_lit(str))
+#define rb_enc_str_new_lit(str, enc) rb_enc_str_new_static((str), rb_strlen_lit(str), (enc))
+#define rb_str_new_literal(str) rb_str_new_lit(str)
+#define rb_usascii_str_new_literal(str) rb_usascii_str_new_lit(str)
+#define rb_utf8_str_new_literal(str) rb_utf8_str_new_lit(str)
+#define rb_enc_str_new_literal(str, enc) rb_enc_str_new_lit(str, enc)
 
 /* struct.c */
 VALUE rb_struct_new(VALUE, ...);