`LinkAssembliesNoShrink` is expensive

[Youssef1313]

Android application type

.NET Android (net7.0-android, etc.)

Affected platform version

Android 33.0.46

Description

This is very very slow.

Steps to Reproduce

Build the app in https://github.com/unoplatform/Uno.Samples/pull/584

Did you find any workaround?

No response

Relevant log output

No response

[dellis1972]

I tried to see if I could repo but the app does not build using dotnet build XamlBrewerUnoApp.Mobile.csproj -bl

error UXAML0001: The type initializer for 'Uno.UI.SourceGenerators.XamlGenerator.XamlCodeGeneration' threw an exception.
 error CS0103: The name 'InitializeComponent' does not exist in the current context
error CS1061: 'PythagorasTreePage' does not contain a definition for 'InitializeComponent' and no accessible extension method 'InitializeComponent' accepting a first argument of type 'PythagorasTreePage' could be found (are you missing a using directive or an assembly reference?)
 error CS0103: The name 'Root' does not exist in the current context 

[Youssef1313]

It's strange. It's building perfectly fine in CI. What exception did XamlCodeGeneration throw?

One thing I noticed is that this task might be doing extra work because we are building in Release where AddKeepAlives is true. So I was suspecting this to be what is taking lots of time. I blindly opened a performance optimization but it might still not be where the task is spending most of its time https://github.com/xamarin/xamarin-android/pull/8422.

[dellis1972]

LinkAssembliesNoShrink should not run in Release, that is a Debug Task. Might be worth checking the properties for AndroidLinkMode in your build log to see why its running that task in Release when it should be running the normal .net linker.

[Youssef1313]

Ah, AndroidLinkMode is None. That is because we explicitly pass PublishTrimmed to false. I think we did that to actually make the build faster

[Youssef1313]

Note: Setting AndroidAddKeepAlives to false takes it down from 9 minutes to 3 seconds.

[jonathanpeppers]

Note: Setting AndroidAddKeepAlives to false takes it down from 9 minutes to 3 seconds.

So, are we testing Debug or Release builds? We are generally more interested in improving build times for Debug builds.

The <LinkAssembliesNoShrink/> task normally runs when the linker/trimmer is disabled (Debug mode).

However, $(AndroidKeepAlives) is only true in a Release build by default:

https://github.com/xamarin/xamarin-android/blob/2f192386e8072f8e0ecaf0de2fe48654f3ade423/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets#L944

$(AndroidIncludeDebugSymbols) is based on DebugSymbols=true or DebugType being set.

I was going to look into skipping AddKeepAlives() for any assembly that is newer than MonoAndroid12.0. But I don't see this code path even hit in a dotnet new maui project build.

@Youssef1313 do you have a .binlog of a build where you were seeing this? Was it, perhaps, Release mode?

[jonathanpeppers]

@Youssef1313 your picture above is Release mode:

Do you have trimming disabled in this app?

[jonpryor]

@jonathanpeppers asked:

Do you have trimming disabled in this app?

Yes, they do:

Ah, AndroidLinkMode is None. That is because we explicitly pass PublishTrimmed to false. I think we did that to actually make the build faster

[Youssef1313]

@jonpryor Yes, it's the release build in CI.

[jonpryor]

We should look into further optimizing AddKeepAlivesStep.cs/etc. to only process assemblies built against Xamarin.Android 11.1 or older, as those versions lack #5278.