diff --git a/builtin.c b/builtin.c
index e4751445..d7e56b34 100644
--- a/builtin.c
+++ b/builtin.c
@@ -596,6 +596,49 @@ static struct symbol_op object_size_op = {
 	.expand = expand_object_size,
 };
 
+#include <string.h>
+static int expand_strlen(struct expression *expr, int cost)
+{
+	struct expression *init, *arg = first_expression(expr->args);
+	unsigned long val = 0;
+
+	if (!arg)
+		return UNSAFE;	// ? ok
+
+	switch (arg->type) {
+	case EXPR_STRING:
+		//todo//
+		break;
+	case EXPR_SYMBOL:
+		if (arg->symbol->ident)
+			goto not_literal;
+
+		init = arg->symbol->initializer;
+		if (!init || init->type != EXPR_STRING)
+			goto not_literal;
+
+		val = strlen(init->string->data);
+		break;
+	default:
+		goto not_literal;
+		break;
+	}
+
+	expr->type = EXPR_VALUE;
+	expr->flags |= CEF_SET_ICE;
+	expr->value = val;
+	expr->taint = 0;
+	return 0;
+
+not_literal:
+	return UNSAFE;
+}
+
+
+static struct symbol_op strlen_op = {
+	.expand = expand_strlen,
+};
+
 /*
  * Builtin functions
  */
@@ -775,7 +818,7 @@ static const struct builtin_fn builtins_common[] = {
 	{ "__builtin_strcpy", &string_ctype, 0, { &string_ctype, &const_string_ctype }},
 	{ "__builtin_strcspn", size_t_ctype, 0, { &const_string_ctype, &const_string_ctype }},
 	{ "__builtin_strdup", &string_ctype, 0, { &const_string_ctype }},
-	{ "__builtin_strlen", size_t_ctype, 0, { &const_string_ctype }},
+	{ "__builtin_strlen", size_t_ctype, 1, { &string_ctype  }, .op = &strlen_op },
 	{ "__builtin_strncasecmp", &int_ctype, 0, { &const_string_ctype, &const_string_ctype, size_t_ctype }},
 	{ "__builtin_strncat", &string_ctype, 0, { &string_ctype, &const_string_ctype, size_t_ctype }},
 	{ "__builtin_strncmp", &int_ctype, 0, { &const_string_ctype, &const_string_ctype, size_t_ctype }},