Cannot AOT compile trimmed FSharp.Core

[kerams]

Apple platform

iOS

Framework version

net10.0-*

Affected platform version

VS 17.14.5, 10.0.100-preview.5.25277.114, 18.4.10622-net10-p5

Description

Similar to dotnet/macios#14813

AOT builds fail when copyused trimming is enabled for FSharp.Core.

1>... Microsoft.iOS.Sdk.net10.0_18.4\18.4.10622-net10-p5\targets\Xamarin.Shared.Sdk.targets(1284,3): error : Failed to AOT compile aot-instances.dll, the AOT compiler exited with code 1.
1>... Microsoft.iOS.Sdk.net10.0_18.4\18.4.10622-net10-p5\targets\Xamarin.Shared.Sdk.targets(1284,3): error : Failed to AOT compile FSharp.Core.dll, the AOT compiler exited with code 1.

Steps to Reproduce

https://github.com/kerams/fsharp-ios-aot

There are 2 lines that use F# types in App.axaml.cs.

Try to compile in Release, see errors. Then remove TrimMode copyused and uncomment IsTrimmable in Theme.iOS.csproj. Complile successfully.

Did you find any workaround?

Disable trimming for FSharp.Core completely with

<ManagedAssemblyToLink Condition="'%(Filename)' == 'FSharp.Core'">
  <IsTrimmable>false</IsTrimmable>
</ManagedAssemblyToLink>

Build logs

No response

[rolfbjarne]

I can reproduce with the provided test project, thanks!

This is what the AOT compiler says:

Could not load signature of Microsoft.FSharp.Core.FSharpFunc`2[T,TResult]:op_Implicit due to: Could not resolve type with token 0100001e from typeref (expected class 'System.Converter`2' in assembly 'System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e') assembly:System.Private.CoreLib, Version=10.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e type:System.Converter`2 member:(null)
Failed to load method 0x600016a from '/Users/rolf/test/bugs/fsharp-ios-aot/Theme.iOS/obj/Release/net10.0-ios/iossimulator-arm64/linked/FSharp.Core.dll' due to Could not resolve signature of method Microsoft.FSharp.Core.FSharpFunc`2[T,TResult]:op_Implicit.

and since it only happens while trimming, it looks like an issue with the trimmer, so I'm moving this to dotnet/runtime.

Binlog: msbuild.binlog.zip

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[vitek-karas]

Possibly related to dotnet/fsharp#18702.
There are two IL modification tools which run before the AOT compiler - ILLink and ILStrip, without detailed investigation it could be either of them to corrupt the IL.

[rolfbjarne]

There are two IL modification tools which run before the AOT compiler - ILLink and ILStrip, without detailed investigation it could be either of them to corrupt the IL.

ILStrip runs after the AOT compiler, otherwise there would be no code to AOT compile.

[vitek-karas]

You're right - I was looking at the binlog and it shows it before... but it doesn't make sense... not sure what I was thinking.