MAUI .NET 8.0 built with Full AOT Compilation reports a lot of `Mono : AOT NOT FOUND`

[crui3er]

Description

When I build maui application for Android with full aot compilation, I see a lot of aot not found log messags for mono aot logger.
Especially for generic class/methods. Even for the ones I expect that should be statically detected.
E.g.:
04-15 18:43:11.957 28518 28518 D Mono : AOT NOT FOUND: System.Collections.Concurrent.ConcurrentDictionary`2<Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceIdentifier, Microsoft.Extensions.DependencyInjection.ServiceProvider/ServiceAccessor>:.ctor ().

04-15 18:43:23.703 28518 28518 D Mono : AOT NOT FOUND: System.Runtime.CompilerServices.AsyncTaskMethodBuilder1<System.Threading.Tasks.VoidTaskResult>:GetStateMachineBox<MauiAotTest.Components.Pages.Weather/<OnInitializedAsync>d__2> (MauiAotTest.Components.Pages.Weather/<OnInitializedAsync>d__2&,System.Threading.Tasks.Task1<System.Threading.Tasks.VoidTaskResult>&).

See attached files: one with full log for the app and the one with aot not found only messages.

LogNote_47021f4c_20240415_18.43.07_tst2_aot_full_not_found.txt
LogNote_47021f4c_20240415_18.43.07_tst2_aot_full.txt

Steps to Reproduce

1. Create a template maui blazor app
2. Build it with AndroidEnableProfiledAot=false and install on Android device
3. Enable mono aot logging with command adb shell setprop debug.mono.log default,timing=bare,assembly,mono_log_level=debug,mono_log_mask=aot
4. Captute log with logcat
5. See a lot of aot not found (exclude the ones for wrappers) log messages.

Link to public reproduction project repository

https://github.com/crui3er/MauiAotTest

Version with bug

8.0.3 GA

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

No response

Did you find any workaround?

No

Relevant log output

No response

[crui3er]

It's also not clear whether should AOT compiler for Android process generic types and methods when $(AndroidEnableProfiledAot)==false
I found it's confusing when reading https://devblogs.microsoft.com/dotnet/dotnet-8-performance-improvements-in-dotnet-maui/#androidstripilafteraot
Looks like it works only for iOS.
Can @jonathanpeppers please shead a light on the subject.
What can I read or may be you can recommend how to reduce jit as much as possible during starting app.

[jonathanpeppers]

I think this is a known issue, some info at the bottom of:

• https://github.com/dotnet/maui/tree/main/src/ProfiledAot#testing-profiles

There are these tiny methods that are always JIT no matter what:

02-23 09:03:46.327 10401 10401 D Mono    : AOT NOT FOUND: (wrapper runtime-invoke) object:runtime_invoke_void (object,intptr,intptr,intptr).
02-23 09:03:46.334 10401 10401 D Mono    : AOT NOT FOUND: (wrapper managed-to-native) System.Diagnostics.Debugger:IsAttached_internal ().
02-23 09:03:46.367 10401 10401 D Mono    : AOT NOT FOUND: (wrapper native-to-managed) Android.Runtime.JNINativeWrapper:Wrap_JniMarshal_PPL_V (intptr,intptr,intptr).

But I don't think these are "actual methods", but tiny wrappers that enable generics or p/invoke. There is some JIT happening there currently on Android, which might be because we use MONO_AOT_MODE=Normal and allow JIT. I believe iOS/Catalyst would use MONO_AOT_MODE=Full, because those platforms require it.

[ivanpovazan]

@crui3er just for my understanding, is there a crash that happens with the application or the question is just about unexpected log messages?

Regarding full AOT compilation on Android, afaik you would have to set -p:AndroidAotMode=Full, @jonathanpeppers please confirm, that would force it (although I am not sure if we are officially supporting this mode). If it isn't set some wrappers will always fallback to JIT during runtime (and AOT NOT FOUND in logs is expected behaviour).

[crui3er]

@ivanpovazan Not, there is no crash, but there are unexpected log messages.
So I am aware that log messages for wrappers are ok (AOT NOT FOUND: (wrapper xxx)). @jonathanpeppers I do not take them in account.
In attached sample (in fact, it's template maui blazor app) jitting is used for stuff in MauiAotTest.Components.Pages.Weather.OnInitializedAsync method or during service provide usage (see my first comment).

In my maui app I working on there are a lot of log messages with AOT NOT FOUND. Even with using recorded aot profile there are jitted methods are which are in recorded profile.

So I am trying to figure out what is going wrong with this small sample app.

[ivanpovazan]

In my maui app I working on there are a lot of log messages with AOT NOT FOUND. Even with using recorded aot profile there are jitted methods are which are in recorded profile.

Could you share more information on that: like the aot profile that you are using and which methods you would not expect to see in the log?

[jonathanpeppers]

I don’t think Full will work on Android, does that mode prevent JIT?

[fanyang-mono]

Full AOT is what iOS uses, which does not JIT anything, since that's a requirement for iOS.

[crui3er]

I tested with -p:AndroidAotMode=Full and it fails on start wtih ExecutionEngineException.

F mono-rt : [ERROR] FATAL UNHANDLED EXCEPTION: System.ExecutionEngineException: Attempting to JIT compile method '(wrapper other) void Java.Interop.JavaVMInterface:PtrToStructure (intptr,object)' while running in aot-only mode. See https://docs.microsoft.com/xamarin/ios/internals/limitations for more information.

[crui3er]

Could you share more information on that: like the aot profile that you are using and which methods you would not expect to see in the log?

I recorded custom aot profile https://github.com/crui3er/MauiAotTest/blob/master/custom.aprof and do test with it.
During recording and testing I do the following actions: start app, go to 'Counter' page, click 'Click me' button several times, then go to 'Weather' page and finally go again to 'Counter' page.

Then I compared AOT NOT FOUND log records and stat file generated from custom profile https://github.com/crui3er/MauiAotTest/blob/master/custom.aprof.stat.txt

Here is a few examples of aot not found records in the log for methods mentioned in profile.

stat:

void System.Runtime.CompilerServices.AsyncMethodBuilderCore:Start (MauiAotTest.Components.Pages.Weather/<OnInitializedAsync>d__2&) 

log:

Mono    : AOT NOT FOUND: System.Runtime.CompilerServices.AsyncMethodBuilderCore:Start<MauiAotTest.Components.Pages.Weather/<OnInitializedAsync>d__2> (MauiAotTest.Components.Pages.Weather/<OnInitializedAsync>d__2&).

stat:

void System.Collections.Concurrent.ConcurrentDictionary`2<Microsoft.AspNetCore.Components.Routing.RouteKey, Microsoft.AspNetCore.Components.Routing.RouteTable>:.ctor ()

log:

Mono    : AOT NOT FOUND: System.Collections.Concurrent.ConcurrentDictionary`2<Microsoft.AspNetCore.Components.Routing.RouteKey, Microsoft.AspNetCore.Components.Routing.RouteTable>:.ctor ().

stat:

System.Type System.Text.Json.Serialization.JsonConverter`1<System.Threading.Tasks.VoidTaskResult>:get_Type ()

log:

Mono    : AOT NOT FOUND: System.Text.Json.Serialization.JsonConverter`1<System.Threading.Tasks.VoidTaskResult>:get_Type ().

Here is AOT NOT FOUND log records excluding the one for wrappers.
LogNote_47021f4c_20240418_16.32.26_tst2_custom_profile_filtered.txt

Sample app is updated. Now it uses recorded aot profile.

[fanyang-mono]

@crui3er Thanks for providing more information about this. I will take a look at this.