1 files changed, 99 insertions, 0 deletions
diff --git a/mono/tests/sgen-toggleref.cs b/mono/tests/sgen-toggleref.cs
new file mode 100644
index 0000000000..d604294fee
--- /dev/null
+++ b/mono/tests/sgen-toggleref.cs
@@ -0,0 +1,99 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Threading;
+using System.Runtime.InteropServices;
+
+public class Toggleref {
+	public int __test;
+	public string id;
+	public List<object> link = new List<object> ();
+	public const int DROP = 0;
+	public const int STRONG = 1;
+	public const int WEAK = 2;
+	
+	~Toggleref () {
+
+	}
+}
+
+[StructLayout (LayoutKind.Explicit)]
+public struct Helper {
+	[FieldOffset(0)]
+	IntPtr ptr;
+	[FieldOffset(0)]
+	object obj;
+	public static IntPtr ObjToPtr (object obj)
+	{
+		Helper h = default (Helper);
+		h.obj = obj;
+		return h.ptr;
+	}
+}
+
+class Driver {
+	static WeakReference<Toggleref> root, child;
+
+	[DllImport ("__Internal", EntryPoint="mono_gc_toggleref_add")]
+	static extern int mono_gc_toggleref_add (IntPtr ptr, bool strong_ref);
+
+	static void Register (object obj)
+	{
+		mono_gc_toggleref_add (Helper.ObjToPtr (obj), true);
+	}
+
+	static void SetupLinks () {
+		var a = new Toggleref () { id = "root" };
+		var b = new Toggleref () { id = "child" };
+		a.link.Add (b);
+		a.__test = Toggleref.STRONG;
+		b.__test = Toggleref.WEAK;
+		Register (a);
+		Register (b);
+		root = new WeakReference<Toggleref> (a, false);
+		child = new WeakReference<Toggleref> (b, false);
+	}
+
+	static Toggleref a, b;
+
+	static int Main ()
+	{
+		
+		var t = new Thread (SetupLinks);
+		t.Start ();
+		t.Join ();
+		
+		GC.Collect ();
+		GC.WaitForPendingFinalizers ();
+
+		Console.WriteLine ("try get A {0}", root.TryGetTarget (out a));
+		Console.WriteLine ("try get B {0}", child.TryGetTarget (out b));
+		Console.WriteLine ("a is null {0}", a == null);
+		Console.WriteLine ("b is null {0}", b == null);
+		if (a == null || b == null)
+			return 1;
+		Console.WriteLine ("a test {0}", a.__test);
+		Console.WriteLine ("b test {0}", b.__test);
+
+		//now we break the link and switch b to strong
+		a.link.Clear ();
+		b.__test = Toggleref.STRONG;
+		a = b = null;
+
+		GC.Collect ();
+		GC.WaitForPendingFinalizers ();
+
+		Console.WriteLine ("try get A {0}", root.TryGetTarget (out a));
+		Console.WriteLine ("try get B {0}", child.TryGetTarget (out b));
+		Console.WriteLine ("a is null {0}", a == null);
+		Console.WriteLine ("b is null {0}", b == null);
+		if (a == null || b == null)
+			return 2;
+		Console.WriteLine ("a test {0}", a.__test);
+		Console.WriteLine ("b test {0}", b.__test);
+
+
+		return 0;
+
+	}
+}
+\ No newline at end of file