To extend the language to support unwinding that crosses FFI boundaries.
Questions:
- stabilization time frame
- talk to package vendors to understand their constraints
- stabilization "MVP"
- add
extern "C unwind"ABI - precise unwinding mechanism is not yet specified but is intended to match the "native unwinding" mechanism
- informally, we will not emit code that intentionally interferes with unwinding
- note that this means that there is no stable way to write code that interacts with "C unwind" ABIs that actually unwind
- call to foreign function with that ABI and it unwinds
- Rust function defined with that ABI unwinds
- behavior of
catch_unwindif a native exception should propagate
- add
- can we stabilize a notion of "idempotent" frames -- could be useful
for signal handlers / longjmp. Would apply potentially to native
frames too. Think of "C code compiled with
-fexceptions". - is setjmp/longjmp in scope? Interacts because of SEH.