Propagate Clang types through SIL

[varungandhi-apple]

First commit is from #29210.

This PR allows us to use the Clang type in IRGen going forward.

[varungandhi-apple]

The commits are showing in the wrong order again 🤦‍♂

[varungandhi-apple]

@swift-ci please test

[varungandhi-apple]

There is a compilation failure as I forgot to update some command line tools like sil-opt. I've fixed that locally pretty easily but there seem to be some crashes compiling the overlays. Looking into those right now.

[varungandhi-apple]

There were several bugs:

1. We were storing the Clang types and this lead to issues around canonical SIL types. The solution for now is to not store it unless we pass the flag explicitly (off-by-default).
2. The Invocation in SILFunctionExtractor and SILOpt did not have the right SILOptions because we didn't record the arguments manually.

@swift-ci please smoke test

If this works, we can run the big tests etc.

[varungandhi-apple]

@swift-ci please clean test

[varungandhi-apple]

Ah the problem is LLDB fails to compile. Let me fix that. 😢

[varungandhi-apple]

swiftlang/llvm-project#609

@swift-ci please test

[rjmccall]

Minor comment but otherwise LGTM

[rjmccall]

This is a very generic name for such a specific type. Can it be made a nested type of SILFunctionType?

[varungandhi-apple]

I tried that earlier, but the template argument in SILFunctionType's TrailingObjects needs the type to be complete. I suspect SILParameterInfo and SILResultInfo have been defined separately instead of as nested inside for a similar reason.

Maybe I should rename it to SILCallingConvUncommonInfo or something else which is more precise?

[varungandhi-apple]

Let me merge this for now, since I don't want to rerun coordinated testing with LLDB again, and this makes doing follow-up work easier. I will change the name in a new PR which can be Swift-only.

[rjmccall]

Okay. SILFunctionTypeUncommonInfo seems reasonable.