Fix NotifyOfCHFFilter notification by advancing stackwalk iterator if in NATIVE_MARKER_FRAME state

[tommcdon]

The FuncEvalFrame and DebuggerU2MCatchHandlerFrame detection in NotifyExceptionPassStarted relied on stale StackFrameIterator state from the end of pass 1. The iterator is no longer guaranteed to be in SFITER_FRAME_FUNCTION state at that point, causing the debugger to never receive the CATCH_HANDLER_FOUND notification during func eval.

Updated fix per feedback from JanVorli:
When there is a transition from a managed frame to an explicit frame, the stack frame iterator returns an extra NATIVE_MARKER_FRAME in between. The fix is to advance once frame past the marker frame to the explicit frame, which will trigger NotifyOfCHFFilter.

Found using internal Visual Studio testing

Fixes #125777

[Copilot]

Pull request overview

This PR fixes a debugger notification regression for exceptions thrown during func eval by moving FuncEvalFrame / DebuggerU2MCatchHandlerFrame detection from NotifyExceptionPassStarted (which could observe stale StackFrameIterator state after pass 1) into SfiNextWorker, where the check runs during pass 1 at the native-transition boundary with live iterator state and direct access to the explicit frame chain.

Changes:

• Removed FuncEvalFrame / DebuggerU2MCatchHandlerFrame detection from NotifyExceptionPassStarted where StackFrameIterator state could be stale.
• Added pass-1 native-transition-time detection in SfiNextWorker and issues NotifyOfCHFFilter when the next explicit frame is FuncEvalFrame (skipping ProtectValueClassFrame) or the topmost DebuggerU2MCatchHandlerFrame.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

src/coreclr/vm/exceptionhandling.cpp:3657

• The NotifyExceptionPassStarted pass-2 branch now has an else { for the reverse-pinvoke case that appears to be missing the expected closing braces for the enclosing else // passNumber == 2 block / function. As written, the brace structure around this empty else block doesn’t look balanced and would fail to compile. Please ensure the reverse-pinvoke else block is properly closed and the surrounding scopes are correctly terminated (or remove the empty else entirely if it’s no longer needed).

    }
}

NOINLINE static void NotifyFunctionEnterHelper(StackFrameIterator *pThis, Thread *pThread, ExInfo *pExInfo)

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

[janvorli]

LGTM, thank you!