Merge pull request #44 from lewurm/isinst-bench

benchmarks: microbenchmark for `isinst` and `castclass`

benchmarks/isinst.benchmark

@@ -0,0 +1,5 @@
+{
+  "Name": "isinst",
+  "TestDirectory": "small",
+  "CommandLine": ["isinst.exe", "25000000"]
+}

tests/small/isinst.cs

@@ -0,0 +1,51 @@
+using System;
+
+public class MyTypes {
+	public class A {
+		public virtual long foo () {
+			return 1;
+		}
+	}
+
+	public class B : A {
+		public override long foo () {
+			return 2;
+		}
+	}
+
+	public class C : A {
+		public override long foo () {
+			return 3;
+		}
+	}
+
+	static bool bench (long iterations, object[] objs) {
+		long checksum = 0;
+		for (long i = 0; i < iterations; ++i) {
+			foreach (object o in objs) {
+				if (o is A) {
+					checksum += ((A) o).foo ();
+				}
+				if (o is B) {
+					checksum += ((B) o).foo ();
+				}
+				if (o is C) {
+					checksum += ((C) o).foo ();
+				}
+			}
+		}
+		return checksum == (4 * iterations);
+	}
+
+	public static void Main (string []args) {
+		long n =  25000000L;
+		object[] objs = new object[4];
+		objs [0] = new object ();
+		objs [1] = new A ();
+		objs [2] = new B ();
+		objs [3] = new C ();
+		if (args.Length > 0)
+			n = Int64.Parse (args[0]);
+		System.Environment.Exit (bench (n, objs) ? 0 : 1);
+	}
+}