Possible to detect AOT mode during runtime?

[sengiv]

This can be helpful when doing A/B testing or when showing AOT version of the app only to desktop users.

For example, we are using Azure CDN to mask 2 versions of the same app,
mobile users get the normal Blazor & desktop users get the AOT version.
With the same domain name.

The obvious solution is to set a flag during the build process of the AOT version.
And this is the direction we are heading.

But is there another straightforward way?

[huoyaoyuan]

Is RuntimeFeature.IsDynamicCodeCompiled sufficient?

[Suchiman]

Benchmark.NET uses this trick to detect which runtime it's running on https://github.com/dotnet/BenchmarkDotNet/blob/1f5637c784ad9887a2d5abdba54d1337655281b1/src/BenchmarkDotNet/Portability/RuntimeInformation.cs#L44-L47

[hez2010]

The BenchmarkDotNet trick is incorrect because PublishSingleFile also produces null for Assembly.Location.
IMO the correct way should be using RuntimeFeature.IsDynamicCodeCompiled.

[sengiv]

@huoyaoyuan

Is RuntimeFeature.IsDynamicCodeCompiled sufficient?

After multiple tests, this does not work (tried in .NET 6 & .NET 7)

I tried the line below just before await webAssemblyHost.RunAsync();
Console.WriteLine(RuntimeFeature.IsDynamicCodeCompiled?"AOT MODE":"NORMAL MODE");
Unfortunately, it only returns false both in AOT and Interpreted.

[hez2010]

How about RuntimeFeature.IsDynamicCodeSupported?

Mode	IsDynamicCodeSupported	IsDynamicCodeCompiled
JIT	True	True
Interpret	True	False
AOT	False	False

[sengiv]

How about RuntimeFeature.IsDynamicCodeSupported?

Mode IsDynamicCodeSupported IsDynamicCodeCompiled
JIT True True
Interpret True False
AOT False False

Thanks a lot @hez2010, RuntimeFeature.IsDynamicCodeSupported is working perfectly.
Tested working in .NET 7