Ensure the FindReferenceTargetsCallback static constructor is called.

[AaronRobinsonMSFT]

The code path in question is executed during a GC. This code path also allocates managed memory, which means it is incompatible to run during a GC. Ensuring the cctor run prior to any GC is the goal of this change.

Fixes #121538

[Copilot]

Pull Request Overview

This PR fixes a critical race condition where the FindReferenceTargetsCallback static constructor could be invoked during garbage collection, causing managed memory allocations in a GC-incompatible code path. The fix ensures the static constructor runs before any GC callbacks are registered.

• Added an EnsureInitialized() method to trigger the static constructor
• Invoked EnsureInitialized() in RegisterGCCallbacks() before GC callbacks are registered

[jkotas]

We should do some validation for this:

• Check that the WinRT tracker test is able to hit this bug when compiled with optimizations off
• Check that the WinRT tracker test is passing with optimizations off with this fix

[AaronRobinsonMSFT]

We should do some validation for this:

• Check that the WinRT tracker test is able to hit this bug when compiled with optimizations off
• Check that the WinRT tracker test is passing with optimizations off with this fix

Done. Found an additional issue when running src/tests/Interop/COM/ComWrappers/API/ComWrappersTests.csproj in Debug under native AOT.

[AaronRobinsonMSFT]

@EgorBo FYI we're adding back two Unsafe.As() uses due to type load during the GC.

[EgorBo]

Is it fine to keep it as is if we have a guarantee that And/Or are always imported as intrinsic?

[jkotas]

we're adding back two Unsafe.As() uses due to type load during the GC.

The problem are allocations caused by

runtime/src/libraries/System.Private.CoreLib/src/System/Threading/Interlocked.cs

Lines 655 to 657 in 3927844

	if ((!typeof(T).IsPrimitive && !typeof(T).IsEnum) ||
	typeof(T) == typeof(float) || typeof(T) == typeof(double) ||
	(typeof(T).IsEnum && (typeof(T).GetEnumUnderlyingType() == typeof(float) || typeof(T).GetEnumUnderlyingType() == typeof(double))))

in non-optimized builds (when these reflection APIs are not expanded as intrinsics by the JIT). It is not really a type load.

[jkotas]

Is it fine to keep it as is if we have a guarantee that And/Or are always imported as intrinsic?

Yes, it would be ok to keep it as is if the JIT can be changed to guarantee that the generic Interlocked.And/Or is imported as an intrinsics that does not call anything that can GC allocate.

[AaronRobinsonMSFT]

/ba-g I've no clue what is going on, but none of it are these changes.