Strip the ILLinkTrim.xml from the System.Diagnostics.StackTrace assembly

[layomia]

The PreserveDependency is already in place -

runtime/src/coreclr/src/System.Private.CoreLib/src/System/Diagnostics/StackFrameHelper.cs

Lines 91 to 92 in 5862ede

	[PreserveDependency("GetSourceLineInfo", "System.Diagnostics.StackTraceSymbols", "System.Diagnostics.StackTrace")]
	[PreserveDependency(".ctor()", "System.Diagnostics.StackTraceSymbols", "System.Diagnostics.StackTrace")]

.

[ghost]

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[eerhardt]

LGTM.

Side note: How are we tracking scenarios to add tests for?

[stephentoub]

I'm not understanding the change. I thought the purpose of this ILLinkTrim_LibraryBuild.xml was to keep the internal and unused API alive through the assembly build such that it would be available to corelib, and then corelib's PreserveDependency ensures it's not trimmed from a consuming app. Why is the PreserveDependency in corelib sufficient to keep the ctor alive in the other assembly in that assembly's build?

[stephentoub]

Oh! I see, this is renaming it to be ILLinkTrim_LibraryBuild.xml, not deleting it. Ok.

[joperezr]

Side note: How are we tracking scenarios to add tests for?

I think we are not 😢. I'm hoping to merge my test PR as soon as possible and will ping you and @layomia in case you had attributes you wanted to add tests for. Or we can also just add a new issue to track that work.

[joperezr]

@layomia just to be sure, how did you look for places that required StackTraceSymbols? I'm just asking so we make sure we checked all platforms in netcoreapp in case we needed an additional attribute to be placed.

[layomia]

how did you look for places that required StackTraceSymbols?

In this case, I discussed with @eerhardt offline and performed this search. I realize that this static search may not uncover all the usages, and I have limited context regarding the various APIs and areas we are performing linker work for. So, I'm sort of relying on area owners to provide additional context. Not sure if there's additional tooling to help out here.

[joperezr]

Not sure if there's additional tooling to help out here.

Fair enough that seems ok to me. @stephentoub are you aware of any other places where we might be using this via reflection? @eerhardt any other tips you have for easily finding linker blind spots for a specific API?

[eerhardt]

any other tips you have for easily finding linker blind spots for a specific API?

Searching is the best weapon I have as of now. That's why reflection is bad 😄.

For this one, the only place I am aware that is using this method is the code in CoreLib @layomia called out, which is already annotated with PreserveDependency. The way you trigger the code is to get an exception and inspect the stack trace and see if line numbers are inserted into the trace.

[layomia]

How are we tracking scenarios to add tests for?

Or we can also just add a new issue to track that work.

I opened #37677.