[il2cpp] Is `sealed` Not Worked As Said Anymore In Unity 2018.3?

In IL2CPP Optimizations: Devirtualization, it suggested use sealed keyword to devirtualization and gain performance.

But when I checked it on my own in Unity 2018.3.5, I found it did not work as the post said.

My Code is simple

Code (CSharp):

1. public class Animal
2. {
3.     public virtual void Speak()
4.     {
5.     }
6. }
7.  
8. public class Dog : Animal
9. {
10.     public override void Speak()
11.     {
12.         Debug.Log("Dog");
13.     }
14. }
15.  
16. public sealed class Cat : Animal
17. {
18.     public override void Speak()
19.     {
20.         Debug.Log("Cat");
21.     }
22. }

And Test code is

Code (CSharp):

1. Cat cat = new Cat();
2. cat.Speak();
3.  
4. Dog dog = new Dog();
5. dog.Speak();

And the IL Code is

Code (CSharp):

1.     // [37 9 - 37 29]
2.     IL_000f: newobj       instance void Cat::.ctor()
3.     IL_0014: stloc.0      // cat
4.  
5.     // [38 9 - 38 21]
6.     IL_0015: ldloc.0      // cat
7.     IL_0016: callvirt     instance void Animal::Speak()
8.     IL_001b: nop
9.  
10.     // [40 9 - 40 29]
11.     IL_001c: newobj       instance void Dog::.ctor()
12.     IL_0021: stloc.1      // dog
13.  
14.     // [41 9 - 41 21]
15.     IL_0022: ldloc.1      // dog
16.     IL_0023: callvirt     instance void Animal::Speak()
17.     IL_0028: nop

The Cpp Code generated by IL2CPP is:

Code (CSharp):

1. Cat_tC86B56F89EF64EBC7575B2E551959B31E9874724 * L_0 = (Cat_tC86B56F89EF64EBC7575B2E551959B31E9874724 *)il2cpp_codegen_object_new(Cat_tC86B56F89EF64EBC7575B2E551959B31E9874724_il2cpp_TypeInfo_var);
2. Cat__ctor_m7757DD1CFFF12E726940C571707FEBB1720A6221(L_0, /*hidden argument*/NULL);
3. VirtActionInvoker0::Invoke(4 /* System.Void Animal::Speak() */, L_0);
4. Dog_tF96DDAC719857CC7A194BF7D3A0776F8D4A6F521 * L_1 = (Dog_tF96DDAC719857CC7A194BF7D3A0776F8D4A6F521 *)il2cpp_codegen_object_new(Dog_tF96DDAC719857CC7A194BF7D3A0776F8D4A6F521_il2cpp_TypeInfo_var);
5. Dog__ctor_m01507A82581E1AD5704DCDA45A9DD230A5A5F764(L_1, /*hidden argument*/NULL);
6. VirtActionInvoker0::Invoke(4 /* System.Void Animal::Speak() */, L_1);

As you can see even I use `sealed` to decorate Cat, but the Cat's Speak is still called by VirtActionInvoker0.

Do you guys meet the same problem? Or am I doing anything wrong?

 

Maybe you can change the post a little bit to make it more precise. Thanks!

 

...It's three years old.

 

Could still warrant a note to explain that it's no longer accurate for new compilers.