[Mono-dev] AOT and generics

[Virgile Bello]

It would be for platforms supporting only AOT.
Of course we would license Mono. We already had a quick discussion about
licensing maybe a year ago (it's still R&D/proof of concept for now, and it
was only Windows until now so we just delayed actual deal until necessary),
but thanks for pointing out, maybe now is a good time to start the
discussion again with Xamarin, I will send an email right away.

On Fri, Jul 6, 2012 at 10:31 PM, Rodrigo Kumpera <kumpera at gmail.com> wrote:

> You need to correctly drive the FullAOT compiler.
> Why do you want to use FullAOT anyway?
> Do you plan to run it on a target that disables JIT?
> Do you hold a license that allows you to do so? Mono is LGPL and FullAOT
> doesn't work with it.
>
> On Fri, Jul 6, 2012 at 9:29 AM, Virgile Bello <virgile.bello at gmail.com>wrote:
>
>> During full AOT, It seems that if generics is a ref type, AOT is skipped
>> (which makes sense because most of the time it is not necessary, one
>> codegen for any ref type is usually enough).
>> However, if the class internally uses a struct based on the generic
>> types, it will fail at runtime.
>> Here is a simple example showcasing the issue:
>>
>> public class B
>> {
>>     public void Test<T>()
>>     {
>>         System.Console.WriteLine(typeof(T));
>>     }
>> }
>>
>> public class A<T>
>> {
>>     public void Test()
>>     {
>>         new B().Test<System.Collections.Generic.KeyValuePair<T, T>>();
>>     }
>> }
>>
>>
>> class P
>> {
>>     static void Main(string[] args)
>>     {
>>         new A<int>().Test();
>>         new A<string>().Test();
>>     }
>> }
>>
>> If I run this program with full aot, it will fail.
>> new A<int> will work (AOT forced because value type)
>> However, new A<string> will generate a JIT exception (because even though
>> string is a ref type, A should be AOT for this specific type because
>> KeyValuePair inside A<T> needs to be JITed.)
>>
>> But maybe I misunderstood the problem (or it is just a specific bug),
>> because this other case actually work (I was expecting it to have the same
>> issue):
>>
>> public class B
>> {
>>     public void Test<T>()
>>     {
>>
>> System.Console.WriteLine(typeof(System.Collections.Generic.KeyValuePair<T,
>> T>));
>>     }
>> }
>>
>> public class A<T>
>> {
>>     public void Test()
>>     {
>>         new B().Test<T>();
>>     }
>> }
>>
>>
>> class P
>> {
>>     static void Main(string[] args)
>>     {
>>         new A<int>().Test();
>>         new A<string>().Test();
>>     }
>> }
>>
>> Just wanted to check if I understood the issue right and if there would
>> be nothing preventing from fixing it?
>> I wouldn't mind taking a look at the sources by myself if necessary.
>>
>> Virgile
>>
>>
>> _______________________________________________
>> Mono-devel-list mailing list
>> Mono-devel-list at lists.ximian.com
>> http://lists.ximian.com/mailman/listinfo/mono-devel-list
>>
>>
>
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