Crash on using Expression.Compile() in a release mode (iOS).

[JaneySprings]

Description

Please see following project to reproduce this issue: https://github.com/JaneySprings/MauiReflectionBug
Same code works perfectly in Xamarin.Forms (iOS release).

Steps to Reproduce

1. Open project folder in terminal
2. Run 'dotnet build -t:run -f:net6.0-ios -p:_DeviceName=insert_device_id_here /p:RuntimeIdentifier=ios-arm64 -c release'

Version with bug

Release Candidate 3 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 15.4

Did you find any workaround?

no

Relevant log output

 System.ExecutionEngineException: Attempting to JIT compile method (wrapper delegate-invoke) int <Module>:invoke_callvirt_int_MyItem (reflecBug.MyItem) while running in aot-only mode. See https://docs.microsoft.com/xamarin/ios/internals/limitations for more information.
2022-05-16 15:16:40.965 reflecBug[93626:11651593]    at System.Linq.Expressions.Interpreter.FuncCallInstruction 2[[reflecBug.MyItem, reflecBug, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[System.Int32, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].Run(InterpretedFrame )
   at System.Linq.Expressions.Interpreter.Interpreter.Run(InterpretedFrame )
   at System.Linq.Expressions.Interpreter.LightLambda.Run(Object[] )
2022-05-16 15:16:40.965 reflecBug[93626:11651593]    at System.Dynamic.Utils.DelegateHelpers.FuncThunk1[Object,Object](Func`2 handler, Object t1)
   at reflecBug.MainPage.GetValue(Object component)
   at reflecBug.MainPage..ctor()

[Eilon]

@rolfbjarne / @stephen-hawley - should this move to https://github.com/xamarin/xamarin-macios ?

[rolfbjarne]

@Eilon this should go to dotnet/runtime, it's an issue with either the AOT compiler or the BCL.

Tagging subscribers to this area: @cston
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Please see following project to reproduce this issue: https://github.com/JaneySprings/MauiReflectionBug
Same code works perfectly in Xamarin.Forms (iOS release).

Steps to Reproduce

1. Open project folder in terminal
2. Run 'dotnet build -t:run -f:net6.0-ios -p:_DeviceName=insert_device_id_here /p:RuntimeIdentifier=ios-arm64 -c release'

Version with bug

Release Candidate 3 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 15.4

Did you find any workaround?

no

Relevant log output

System.ExecutionEngineException: Attempting to JIT compile method (wrapper delegate-invoke) int :invoke_callvirt_int_MyItem (reflecBug.MyItem) while running in aot-only mode. See https://docs.microsoft.com/xamarin/ios/internals/limitations for more information.
2022-05-16 15:16:40.965 reflecBug[93626:11651593] at System.Linq.Expressions.Interpreter.FuncCallInstruction 2[[reflecBug.MyItem, reflecBug, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[System.Int32, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].Run(InterpretedFrame )
at System.Linq.Expressions.Interpreter.Interpreter.Run(InterpretedFrame )
at System.Linq.Expressions.Interpreter.LightLambda.Run(Object[] )
2022-05-16 15:16:40.965 reflecBug[93626:11651593] at System.Dynamic.Utils.DelegateHelpers.FuncThunk1[Object,Object](Func`2 handler, Object t1)
at reflecBug.MainPage.GetValue(Object component)
at reflecBug.MainPage..ctor()

Author:	JaneySprings
Assignees:	-
Labels:	area-System.Linq.Expressions, untriaged, t/bug, platform/iOS 🍎, fatal
Milestone:	-

Tagging subscribers to 'os-ios': @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Description

Please see following project to reproduce this issue: https://github.com/JaneySprings/MauiReflectionBug
Same code works perfectly in Xamarin.Forms (iOS release).

Steps to Reproduce

1. Open project folder in terminal
2. Run 'dotnet build -t:run -f:net6.0-ios -p:_DeviceName=insert_device_id_here /p:RuntimeIdentifier=ios-arm64 -c release'

Version with bug

Release Candidate 3 (current)

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 15.4

Did you find any workaround?

no

Relevant log output

System.ExecutionEngineException: Attempting to JIT compile method (wrapper delegate-invoke) int :invoke_callvirt_int_MyItem (reflecBug.MyItem) while running in aot-only mode. See https://docs.microsoft.com/xamarin/ios/internals/limitations for more information.
2022-05-16 15:16:40.965 reflecBug[93626:11651593] at System.Linq.Expressions.Interpreter.FuncCallInstruction 2[[reflecBug.MyItem, reflecBug, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[System.Int32, System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].Run(InterpretedFrame )
at System.Linq.Expressions.Interpreter.Interpreter.Run(InterpretedFrame )
at System.Linq.Expressions.Interpreter.LightLambda.Run(Object[] )
2022-05-16 15:16:40.965 reflecBug[93626:11651593] at System.Dynamic.Utils.DelegateHelpers.FuncThunk1[Object,Object](Func`2 handler, Object t1)
at reflecBug.MainPage.GetValue(Object component)
at reflecBug.MainPage..ctor()

Author:	JaneySprings
Assignees:	-
Labels:	area-System.Linq.Expressions, untriaged, os-ios, t/bug, fatal
Milestone:	-

[steveisok]

I can reproduce in .net 6. Under .NET 7, the message is a bit more friendly

Expression must be readable (Parameter 'expression') (System.ArgumentException)
   at System.Dynamic.Utils.ExpressionUtils.RequiresCanRead(Expression , String , Int32 )
   at System.Linq.Expressions.Expression.Convert(Expression , Type , MethodInfo )
   at System.Linq.Expressions.Expression.Convert(Expression , Type )
   at Program.CompileLambda()
   at Program.GetValue(Object )
   at Program.Main(String[] )
   at Program.<Main>(String[] )

@akoeplinger do you know of any mono trickery that was done in the past?

@MichalStrehovsky do you have any insight into if this can even work in runtime?

[MichalStrehovsky]

@MichalStrehovsky do you have any insight into if this can even work in runtime?

Following adapted snippet placed in a console app works with NativeAOT full AOT mode, so this looks like it has more to do with how S.L.Expressions is configured for iDevices than with AOT:

using System.Linq.Expressions;

var item = new MyItem();
item.Id = 100;

try
{
    Console.WriteLine(GetValue(item));
}
catch (Exception e)
{
    Console.WriteLine(e);
}

static object GetValue(object component)
{
    Func<object, object> propertyAccessorDelegate = CompileLambda();
    return propertyAccessorDelegate(component);
}

static Func<object, object> CompileLambda()
{
    ParameterExpression parameter = Expression.Parameter(typeof(object), "p");
    MemberExpression property = Expression.Property(Expression.Convert(parameter, typeof(MyItem)), "Id");
    Expression<Func<object, object>> lambda = Expression.Lambda<Func<object, object>>(Expression.Convert(property, typeof(object)), parameter);
    return lambda.Compile();
}

public class BaseItem
{
    int id;

    public virtual int Id
    {
        get => id;
        set => this.id = value;
    }
}

public class MyItem : BaseItem
{
    int id;

    //Some attributes....
    public override int Id { get => base.Id; set => base.Id = value; }
}

The Expression must be readable (Parameter 'expression') (System.ArgumentException) failure mode that @steveisok hit looks suspicious - it would indicate an issue with the LINQ expression interpreter and I would expect it to be hittable with CoreCLR by swapping return lambda.Compile() in the repro case with return lambda.Compile(preferInterpretation: true). This forces LINQ expressions to go down the interpreter paths even if Ref.Emit is available. But it's not hittable on CoreCLR (without full AOT) with the above repro.

The originally reported issue ("Attempting to JIT compile method") might be related to what I called out in #61952 in my comments around iDevices/iOS: there are more codepaths in S.L.Expressions that should be activated for a full AOT experience. Some of these codepaths require extra runtime support - it's code around CanEmitObjectArrayDelegate and CanCreateArbitraryDelegates.

I think the tests that got disabled for iDevices in #54970 are testing this functionality but it doesn't look like the failures got looked at since then.