Set target.swift-* lldb settings

[brentleyjones]

Part of #617.

This allows lldb to work correctly if using the -noserialize-debugging-options swiftc flag.

[brentleyjones]

Almost there. These two keys don't match. Trying to figure out when we need to add the minimum os to the triple:

lldb: "arm64-apple-macosx11.0.0 tests.xctest/Contents/MacOS/tests"
generated: "arm64-apple-macosx tests.xctest/Contents/MacOS/tests"

[brentleyjones]

I swear I was seeing the triples without the os version before. Now I only see the one with os version. Maybe I can add a fallback key lookup just in case...

[brentleyjones]

Regardless, latest issue is that these two don't match:

lldb: "arm64-apple-macosx11.0.0 tests.xctest/Contents/MacOS/tests"
generated: "arm64-apple-macosx12.0.0 tests.xctest/Contents/MacOS/tests"

I have --macos_minimum_os=12.0 set, so I'm not sure what's up with that yet.

[brentleyjones]

And now it works. Hmmmmm 🤔. I'm thinking it was some sort of caching issue (multiple Xcode projects open, both of them stopped in lldb...), so we just need the one backup now, though maybe I can convert the lldb one to the generic one when doing that. The downside is the small chance of collisions if there are multiple versions of executable paths that only differ on os version, but the backup is better than nothing.

[brentleyjones]

Fallback added, I think this is good to go.

@jpsim It would be nice to make sure that this doesn't regress debugging for EM. It doesn't set the flag that removes debug information (--features=swift.cacheable_swiftmodules) but EM already sets that, so this should only improve debugging of Swift code for you.

@cgrindel can you test this on your internal project as well?

[brentleyjones]

(And I found the 11.0 vs 12.0, and it's related to generator's tests. Digging in.)

[brentleyjones]

And now that is fixed! Was looking at yet another wrong place for the triple. So many places to get it in lldb...

[jpsim]

Lightweight debugging testing with EM seems to still work. I didn't review the changes here in depth though, there's a lot that was touched.

[brentleyjones]

I got a couple offline reports of this working, so merging.