Correctly escape RegExp source.

test/mjsunit/regress/regress-3229.js

Index: test/mjsunit/regress/regress-3229.js
diff --git a/test/mjsunit/regress/regress-3229.js b/test/mjsunit/regress/regress-3229.js
new file mode 100644
index 0000000000000000000000000000000000000000..1a0ed64412e628f4eaae7bc0dc773f47ac79d11b
--- /dev/null
+++ b/test/mjsunit/regress/regress-3229.js
@@ -0,0 +1,26 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Escape '/'.
+function testEscapes(expected, regexp) {
+  assertEquals(expected, regexp.source);
+  assertEquals("/" + expected + "/", regexp.toString());
+}
+
+testEscapes("\\/", /\//);
+testEscapes("\\/\\/", /\/\//);
+testEscapes("\\/", new RegExp("/"));
+testEscapes("\\/", new RegExp("\\/"));
+testEscapes("\\\\/", new RegExp("\\\\/"));
+testEscapes("\\/\\/", new RegExp("\\/\\/"));
+testEscapes("\\/\\/\\/\\/", new RegExp("////"));
+testEscapes("\\/\\/\\/\\/", new RegExp("\\//\\//"));
+testEscapes("(?:)", new RegExp(""));
+testEscapes("(?:)", RegExp.prototype);
+
+// Read-only property.
+var r = /\/\//;
+testEscapes("\\/\\/", r);
+r.source = "garbage";
+testEscapes("\\/\\/", r);