[davidwrighton]

Summary

Use InterpreterGcInfoDecoder rather than the target-native GcInfoDecoder when inspecting an interpreted frame in:

• SfiNextWorker, for reverse-P/Invoke detection during exception propagation.
• SafeToReportGenericParamContext, for the generic-context prolog length.
• FindFirstInterruptiblePoint, for the GC-reporting location when unwinding between funclets.

Interpreter GC metadata has different encoding parameters and normalization from native metadata. Select the decoder using the frame's code manager, guarded by FEATURE_INTERPRETER, and preserve the existing decoder for native frames.

Found while investigating #135821. This PR is independently based on main and contains no Wasm metadata-format or code-generation changes. The decoder mismatch predates that work; an observable release-mode iOS failure has not been demonstrated.

Validation

• ./build.sh clr.runtime -rc Checked on this standalone branch: passed, zero warnings and errors.
• Session-local caught-exception, generic-GC, and uncaught reverse-P/Invoke probes on this standalone branch: passed with normal execution and with DOTNET_Interpreter='*' DOTNET_ReadyToRun=0. The uncaught probe terminated as expected and retained MessageFromMyException.
• On the Wasm metadata branch, the reverse-P/Invoke probe reproduced the missing-message/assertion failure before this fix and preserved the exception message afterward; the checked browser runtime build also passed. This is supplementary evidence, not a standalone-branch browser test.
• git diff upstream/main...HEAD --check: passed.
• No new checked-in regression test; existing WasmBuildAppTest.ExceptionFromMain caught the EH regression.
• iOS execution and the full test suites were not run.

Note

This pull request description and code changes were generated with GitHub Copilot.

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[Copilot]

🔵 Needs a closer look

Runtime-maintainer validation is needed for interpreter GC-root reporting in active/interrupted generic frames and GC during funclet-to-funclet unwinds, since the reported smoke probes do not establish coverage of these paths.

No open issues 🎉

What changed in this PR

This PR updates CoreCLR frame inspection to use InterpreterGcInfoDecoder for interpreted frames, matching their GC metadata encoding while preserving native-frame decoding.

Changes:

• Selects the interpreter decoder for reverse-P/Invoke detection during exception propagation.
• Uses it for generic-context prolog lengths and interruptible-range lookup during funclet unwinding.
• Guards interpreter-specific paths with FEATURE_INTERPRETER.

File	Description
src/​coreclr/​vm/​gcenv.ee.common.cpp	Selects the frame-appropriate decoder for prolog lengths and interruptible ranges.
src/​coreclr/​vm/​exceptionhandling.cpp	Selects the frame-appropriate decoder for reverse-P/Invoke detection.

_{Review effort: Balanced}

[BrzVlad]

Wondering if it makes sense to have a shared GcInfoDecoder which is implemented by InterpreterGcInfoDecoder and a JITGcInfoDecoder, to avoid some code duplication.

[davidwrighton]

/ba-g the failures are known issues.

[davidwrighton]

/backport to release/11.0

[github-actions]

Started backporting to release/11.0 (link to workflow run)

[github-actions]

@davidwrighton backporting to release/11.0 was not run because the source pull request has not been merged. Please merge this pull request before requesting a backport.

[davidwrighton]

/backport to release/11.0

[github-actions]

Started backporting to release/11.0 (link to workflow run)