[cxx-interop][libswift] Use std::string instead of BridgedStringRef 🚀

[zoecarver]

No description provided.

[zoecarver]

Something we'll need to do here is guard on the Swift version so we don't try to build with a version of the Swift compiler that can't import the C++ stdlib.

[eeckstein]

Is there a reason why you would the *_debugDescription functions return a std::string and not a llvm::StringRef?

[zoecarver]

Is there a reason why you would the *_debugDescription functions return a std::string and not a llvm::StringRef?

It's what's used in the swift compiler. Eventually we want to remove as much of this bridging as possible and just use .debugDescription, so we should match the APIs as closely as possible. Also, it would require us to allocate/convert the string, and it's nice to get rid of that.

[zoecarver]

Oh, and another reason (not a very good one but still): this allows us to not pull in any extra header includes which makes this patch simpler. I think it would be good to not touch any of the LLVM or Swift headers on the first go (other than the bridging headers which we already import and are pretty simpler).

[eeckstein]

Yes, sorry, I mixed that up with Function.name. For debugDescription it makes sense to pass it as a std::string.

[eeckstein]

lgtm!

[zoecarver]

I guess Egor's patch for this didn't quite make it into 5.5 :(

[zoecarver]

@swift-ci please smoke test.

[zoecarver]

@swift-ci please smoke test macOS.

[zoecarver]

@swift-ci please test Windows.

[zoecarver]

@swift-ci please test Windows.