mono/tests/dynamic-method-resurrection.cs

   1 using System;
   2 using System.Reflection;
   3 using System.Reflection.Emit;
   4 using System.Runtime.InteropServices;
   5 using System.Runtime.CompilerServices;
   6
   7 delegate int Getter ();
   8
   9 class Host {
  10
  11         static int Field = 42;
  12
  13         Getter g;
  14
  15         public Host (Getter g) {
  16                 this.g = g;
  17         }
  18
  19         ~Host () {
  20                 Program.resed = g;
  21         }
  22 }
  23
  24
  25 class Program {
  26                 internal static Getter resed;
  27                 static int result;
  28                 static void DoStuff ()
  29         {
  30                         DynamicMethod method = new DynamicMethod ("GetField",
  31                         typeof (int), new Type [0], Type.GetType ("Host"));
  32
  33                         ILGenerator il = method.GetILGenerator ();
  34                         il.Emit (OpCodes.Ldsfld, typeof (Host).GetField ("Field", BindingFlags.Static | BindingFlags.NonPublic));
  35                         il.Emit (OpCodes.Ret);
  36
  37                         var g = (Getter)method.CreateDelegate (typeof (Getter));
  38                         new Host (g);
  39         }
  40
  41                 static bool CheckStuff () {
  42                         if (resed == null)
  43                                 return false;
  44                         Program.result = resed ();
  45                         resed = null;
  46                         return true;
  47                 }
  48
  49                 public static int Main ()
  50         {
  51                         int cnt = 5;
  52                         DoStuff ();
  53                         do {
  54                                 if (CheckStuff ())
  55                                         break;
  56                                 GC.Collect ();
  57                                 GC.WaitForPendingFinalizers ();
  58                         } while (cnt-- > 0);
  59                         GC.Collect ();
  60                         GC.WaitForPendingFinalizers ();
  61                         return result == 42 ? 0 : 1;
  62                 }
  63 }