tracking issue for ffi-unwind

[nikomatsakis]

Summary

Working out the rules for cross-language unwinding as well as longjmp.

Status

This section lists the efforts that we are working towards.

"C-unwind" ABI

The "C-unwind" ABI allows you to invoke foreign functions that may unwind using the native ABI.

• Specification: RFC: 'C-unwind' ABI rfcs#2945 has been merged. This RFC introduces the "C-unwind" ABI.
• Implementation: We are looking for someone to implement! The tracking issue for the implementation work is Tracking Issue for "C-unwind ABI", RFC 2945 rust#74990.

Interaction with catch_unwind

We need to define what happens when foreign exceptions interact with catch_unwind.

longjmp compatibility

We need to define the conditions in which it is legal to longjmp through Rust frames. We've done some initial conversation about this.

Links

• Repository
• Zulip-stream: #project-ffi-unwind
• Moved from ffi-unwind lang-team#19

[BatmanAoD]

"C-unwind" is fully stabilized.

catch_unwind is now safe to use with "foreign" exceptions, although the implementation currently just aborts. We would like to permit disposing, and/or catching & rethrowing.

The converse, C++ or other runtimes catching Rust panic objects and either disposing or rethrowing, is not yet defined. We currently always abort.

No progress yet on longjmp.