generics with IL?

Question

Is it possible to use generics with the IL Generator?

        DynamicMethod method = new DynamicMethod(
            "GetStuff", typeof(int), new Type[] { typeof(object) });

        ILGenerator il = method.GetILGenerator();

        ... etc

Answer 1

Yes, it is possible, but not with the DynamicMethod class. If you are restricted to using this class, you're out of luck. If you can instead use a MethodBuilder object, read on.

Emitting the body of a generic method is, for most intents and purposes, no different from emitting the body of other methods, except that you can make local variables of the generic types. Here is an example of creating a generic method using MethodBuilder with the generic argument T and creating a local of type T:

MethodBuilder method;
//... Leaving out code to create MethodBuilder and store in method
var genericParameters = method.DefineGenericParameters(new[] { "T" });
var il = method.GetILGenerator();
LocalBuilder genericLocal = il.DeclareLocal(genericParameters[0]);

To emit a call to that generic method from another method, use this code. Assuming method is a MethodInfo or MethodBuilder object that describes a generic method definition, you can emit a call to that method with the single generic parameter int as follows:

il.EmitCall(OpCodes.Call, method.MakeGenericMethod(typeof(int)), new[] { typeof(int) }));