C#•2mo ago

NativeAOT Serialization Troubles

I'm trying to serialize the following (in an ideally fast manner and binary format, but I am willing to compromise) using NativeAOT (this is a requirement!): A class containing a custom SparseSet (2 arrays internally) implementation containing a set of classes deriving from a shared interface. I'm currently using MemoryPack for this, however it is not working whatsoever, and the following error occurs:

Process terminated. Failed to create generic virtual method implementation

Declaring type: MemoryPack.Formatters.MemoryPackableFormatter`1<GameCore.Scenes.Scene>
Method name: Serialize
Instantiation:
  Argument 00000000: MemoryPack.Internal.ReusableLinkedArrayBufferWriter

   at System.RuntimeExceptionHelpers.FailFast(String, Exception, String, RhFailFastReason, IntPtr, IntPtr) + 0x249
   at Internal.Runtime.TypeLoader.TypeLoaderEnvironment.ResolveGenericVirtualMethodTarget(RuntimeTypeHandle, RuntimeMethodHandle) + 0x256
   at System.Runtime.TypeLoaderExports.<>c.<GVMLookupForSlotSlow>b__8_0(IntPtr, IntPtr, Object, IntPtr&) + 0x3e
   at System.Runtime.TypeLoaderExports.CacheMiss(IntPtr, IntPtr, RuntimeObjectFactory, Object) + 0x3c
   at System.Runtime.TypeLoaderExports.GVMLookupForSlotSlow(Object, RuntimeMethodHandle) + 0x68
   at System.Runtime.TypeLoaderExports.GVMLookupForSlot(Object, RuntimeMethodHandle) + 0x91
   at MemoryPack.MemoryPackWriter`1.WriteValue[T](T&) + 0x3d
   at MemoryPack.MemoryPackSerializer.Serialize[T](T&, MemoryPackSerializerOptions) + 0x342
   at Game.Main(String[] args) + 0xaa

Process terminated. Failed to create generic virtual method implementation

Declaring type: MemoryPack.Formatters.MemoryPackableFormatter`1<GameCore.Scenes.Scene>
Method name: Serialize
Instantiation:
  Argument 00000000: MemoryPack.Internal.ReusableLinkedArrayBufferWriter

   at System.RuntimeExceptionHelpers.FailFast(String, Exception, String, RhFailFastReason, IntPtr, IntPtr) + 0x249
   at Internal.Runtime.TypeLoader.TypeLoaderEnvironment.ResolveGenericVirtualMethodTarget(RuntimeTypeHandle, RuntimeMethodHandle) + 0x256
   at System.Runtime.TypeLoaderExports.<>c.<GVMLookupForSlotSlow>b__8_0(IntPtr, IntPtr, Object, IntPtr&) + 0x3e
   at System.Runtime.TypeLoaderExports.CacheMiss(IntPtr, IntPtr, RuntimeObjectFactory, Object) + 0x3c
   at System.Runtime.TypeLoaderExports.GVMLookupForSlotSlow(Object, RuntimeMethodHandle) + 0x68
   at System.Runtime.TypeLoaderExports.GVMLookupForSlot(Object, RuntimeMethodHandle) + 0x91
   at MemoryPack.MemoryPackWriter`1.WriteValue[T](T&) + 0x3d
   at MemoryPack.MemoryPackSerializer.Serialize[T](T&, MemoryPackSerializerOptions) + 0x342
   at Game.Main(String[] args) + 0xaa

I've attached a sample of this scenario reproducing the above error. It works fine when not using NativeAOT, but as I mentioned NAOT is a requirement for me. If anyone has any ideas on how to get this to serialize at all - no matter using what library or whatever - please inform me!

Program.cs

9 Replies

ero•2mo ago

https://github.com/Cysharp/MemoryPack#native-aot

Angius•2mo ago

Should be fixed in 8.0 tho

NolramOP•2mo ago

This issue is happening on .NET 9, so clearly something still seems wrong I have read this and followed their documentation, but as I just mentioned, the issue still occurs. Other MemoryPack serialisations work; just not this stack of generic container & interface-derived class

Decrypted•2mo ago

Iirc we had some issues where ModuleInitializer was not called with NativeAOT for some reason and union types were not registered. Had to manually register them. Like

// (ushort, Type)[]
var formatter = new DynamicUnionFormatter<IFooBarBaz>(
    (0, typeof(Foo)),
    (1, typeof(Bar)),
    (2, typeof(Baz))
);

MemoryPackFormatterProvider.Register(formatter);

// (ushort, Type)[]
var formatter = new DynamicUnionFormatter<IFooBarBaz>(
    (0, typeof(Foo)),
    (1, typeof(Bar)),
    (2, typeof(Baz))
);

MemoryPackFormatterProvider.Register(formatter);

Could also have been that none of the ModuleInitializers were called and as a result all types had to be registered manually. Don't have access to the project anymore and cannot check sorry

NolramOP•2mo ago

Thank you for your input - I have already tried this, and unfortunately this does not solve the issue. The issue does not seem to be that NAOT is stripping out serialisation logic, but rather that something in the NAOT runtime itself seems to fail.

Clément•2mo ago

Did you already try to configure the trimmer with a root descriptor file to tell it not to trim away specific assemblies/types/... ?

NolramOP•2mo ago

I believe I have - but I can try again, just in case. (Git issue about this: https://github.com/dotnet/runtime/issues/113664)

NolramOP•2mo ago

Seems a PR regarding this issue has been created! https://github.com/dotnet/runtime/pull/113684

GitHub

Fix dynamic static generic virtual method dispatch on generic types...

Fixes #113664. When we resolve dispatch for a static generic virtual method dynamically (e.g. after MakeGenericType or another generic virtual method call) we run the runtime type loader logic to d...

NolramOP•2mo ago

... and merged!

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NativeAOT Serialization Troubles

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