Discussion: Using custom crossgen for JitBench

[vkvenkat]

I'm looking for a way to force the dotnet store in AspNet-GenerateStore.ps1 to pickup a custom crossgen (say, available at D:\coreclr\bin\Product\Windows_NT.x64.Release) to generate native images, rather than use the version pulled in to JitBench\.temp\Optimize\netcoreapp. Any suggestions for this? @rynowak @litian2025

[rynowak]

The best place to ask for this might be https://github.com/dotnet/sdk - I neither work on the SDK nor the CLR so I don't have much experience for the workflow of using custom builds.

The msbuild file that fundamentally runs the store is here: https://github.com/dotnet/sdk/blob/b5aa4a2b0db4f6203050063139e1873fa024337a/src/Tasks/Microsoft.NET.Build.Tasks/build/Microsoft.NET.ComposeStore.targets

---

/cc @eerhardt @JosephTremoulet in case they have any ideas about the best way to proceed

[vkvenkat]

Thanks for the pointer! I'll ask there and reply back once I have my solution.

[JosephTremoulet]

FWIW, when I want to use a custom clrjit.dll, then, working in the dev branch of JitBench, I just copy clrjit.dll out of D:\coreclr\bin\Product\Windows_NT.x64.Release over top of the copy under the local .dotnet directory. I'd imagine the same would work for crossgen.exe.

[eerhardt]

The crossgen executable that dotnet store uses is resolved from the runtime.{RID}.Microsoft.NETCore.App NuGet package. See

https://github.com/dotnet/sdk/blob/cd25d6bbfc2aac61cc790c511900427ac64fdaa8/src/Tasks/Microsoft.NET.Build.Tasks/build/Microsoft.NET.CrossGen.targets#L60-L89

I tried overwriting the /p:CrossgenDir property on the command line, but that doesn't work since these properties are being set in a Target, and unconditionally set. If we wanted to support this scenario more, we could change that code to check if the property was already defined.

I haven't tried @JosephTremoulet's recommendation, but that sounds reasonable - overwriting the file in the NuGet cache, which is where dotnet store will pick it up from. ex. C:\Users\eerhardt\.nuget\packages\runtime.win-x64.microsoft.netcore.app\2.0.0\runtimes\win-x64\native\..\..\..\tools.

[vkvenkat]

Thanks for the suggestions! Overwriting the crossgen executable at C:\Users\Varun\.nuget\packages\runtime.win-x64.microsoft.netcore.app\2.1.0-preview2-25616-02\tools was the easiest fix for this.

[rynowak]

Cool, glad you found a solution.

I'm re-opening this to track updating the docs to explain this. If you this suggestion please file an issue on SDK so they can track the feedback.

[vkvenkat]

Done: #1614