Runtime: expose demangle() in Runtime module #84788
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ktoso commented Oct 9, 2025
stdlib/public/runtime/Backtrace.cpp Outdated
| char *outputBuffer, | ||
| size_t *outputBufferSize) { | ||
| size_t *outputBufferSize, | ||
| uint32_t flags) { |
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kinda future proofing... i learnt painfully that we "always" need flags in runtime funcs.
ktoso commented Oct 9, 2025
stdlib/public/runtime/Backtrace.cpp Outdated
| if (flags == 1) { | ||
| // simplified display options, for backtraces | ||
| options = DemangleOptions::SimplifiedUIDemangleOptions(); | ||
| } |
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Keeping the current behavior you did for backtracer @al45tair
ktoso commented Oct 9, 2025
Azoy reviewed Oct 9, 2025
We should finally expose the demangle functionality; It's been widely used by calling into internal _swift_demangle and instead we should offer a real API. Previous discussions 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.
ktoso force-pushed the wip-demangle-string branch from 6402000 to 899d2e9 Compare | @swift-ci please smoke test |
We should finally expose the demangle functionality; It's been widely used by calling into internal _swift_demangle and instead we should offer a real API. Previous discussions 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.
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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 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.
cc @Azoy @al45tair