Issues with Linking NativeAOT (ILC) Compiled Object File for EFI Application on macOS (.NET8 RC1)

[ZeroLP]

Hello,

I am encountering issues while trying to build and link a NativeAOT compiled object file for an EFI application on macOS. Below are the details of the problem and the steps I have taken so far:

Problem Description:
I am working on a project where I need to compile C# code using ILC and link the resulting object file to create an EFI application. The development environment is macOS M1, and I am targeting the x86_64 architecture on .NET8 RC1.

Steps Taken:
Compilation with ILC:
I used the following command to compile the C# code using .NET Native:

csc /nologo /debug:embedded /noconfig /nostdlib /runtimemetadataversion:v4.0.30319 <source_files> /out:EFINet8Test /langversion:latest /unsafe
ilc EFINet8Test -o EFINet8Test.obj --systemmodule EFINet8Test--map EFINet8Test.map -O

Project-Level Compilation with dotnet build:
I also tried defining the csc arguments at the project level in the .csproj file properties and then built the project using dotnet build to ensure that the correct C# version and .NET 8 SDK were being used. However, this did not resolve the issue.

Linking with Clang:
I attempted to link the compiled object file using clang with the following command:
clang -o BOOTX64.EFI -target x86_64-unknown-windows -ffreestanding -nostdlib -e EfiMain EFINet8Test.obj -fuse-ld=/usr/local/opt/llvm/bin/lld-link

However, this resulted in an "unknown file type" error, indicating that lld-link does not recognise the format of the .obj file produced by ILC.

Exploration of Alternatives:

• I explored using different linkers such as lld-link and ld from MinGW-w64, but none recognised the ILC-produced .obj file format.
• I considered converting the object file format using objcopy, but this approach has its complexities.
• I also attempted to pass custom clang arguments through the .csproj file using the IlcArg property, but the issue persisted.

Questions:

• Is there a known solution or workaround for linking ILC-compiled object files for EFI applications on macOS?
• Are there alternative linkers or tools that can recognise and link the .obj file produced by NativeAOT on macOS?
• Is it possible to provide custom clang arguments or specify a custom linker through MSBuild or .csproj settings to address this issue?

Any guidance, suggestions, or insights into this problem would be greatly appreciated. Thank you in advance for your help!