The demangle API (`demangle()`) didn't make it into release/6.3, so its
availability should be 6.4.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
We should expose the demangle functionality; It's been widely used by
calling into internal _swift_demangle and instead we should offer a real
API. It's also already used in the Runtime module already when forming
backtraces.
[Previous
discussions](https://forums.swift.org/t/demangle-function/25416/15)
happened between 2019 and 2024, and just never materialized in a
complete implementation and proposal.
Right now, even more tools are in need of this API, as we are building
continious profiling solutions etc, so it is a good time to revisit this
topic.
This PR is roughly based off @Azoy's
https://github.com/swiftlang/swift/pull/25314/files#diff-fd379a721cc9a1c9ef6486eae713e945da842b42170d4d069029a57334371eba
from 2019, however it brings it over to the new Runtime module which is
a great place to put this functionality - even Backtrace had to recently
reinvent calling the demangling infra in this module.
Pending SE review, [proposal
here](https://github.com/swiftlang/swift-evolution/pull/2989).
cc @azoy @al45tair
---------
Co-authored-by: Alastair Houghton <alastair@alastairs-place.net>
Allan Shortlidge
Konrad `ktoso` Malawski
eeckstein