missing c++ interop components in toolchain build for Windows

[compnerd]

Building the latest 5.9 snapshot fails to package due to missing files.

https://dev.azure.com/compnerd/swift-build/_build/results?buildId=61846&view=logs&j=3d6d6336-35c7-5975-2a77-9c4cad333d2b&t=abe84523-3dab-5ac8-8c4b-5a986786345c

##[error]platforms\Windows\sdk-amd64.wxs(449,0): Error WIX0103: Cannot find the File file 'D:\a\1/windows-sdk-amd64/Library/Developer/Platforms/Windows.platform/Developer/SDKs/Windows.sdk\usr\lib\swift\windows\x86_64\libcxxshim.h'. The following paths were checked: D:\a\1/windows-sdk-amd64/Library/Developer/Platforms/Windows.platform/Developer/SDKs/Windows.sdk\usr\lib\swift\windows\x86_64\libcxxshim.h
##[error]platforms\Windows\sdk-amd64.wxs(453,0): Error WIX0103: Cannot find the File file 'D:\a\1/windows-sdk-amd64/Library/Developer/Platforms/Windows.platform/Developer/SDKs/Windows.sdk\usr\lib\swift\windows\x86_64\libcxxshim.modulemap'. The following paths were checked: D:\a\1/windows-sdk-amd64/Library/Developer/Platforms/Windows.platform/Developer/SDKs/Windows.sdk\usr\lib\swift\windows\x86_64\libcxxshim.modulemap

We are failing to install libcxxshim.h and libcxxshim.modulemap.

[hyp]

@compnerd is that something you're going to be fixing for 5.9?

[compnerd]

I think that we should fix this for 5.9. If you can get it fixed before I can that would be great - but this is blocking the Windows releases on 5.9 :-(.

[hyp]

Cc @egorzhdan do you know what's going wrong here?

[hyp]

@compnerd why do we need them to be under x86_64\libcxxshim.modulemap? they should be just in windows I believe. What kind of check is looking for these files?

[compnerd]

The installer places them at x86_64, I couldn't really tell you why that path over the architecture agnostic one (I suspect that it is where it is on the other platforms as well).

https://github.com/apple/swift-installer-scripts/blob/release/5.9/platforms/Windows/sdk-amd64.wxs#L447-L455

[hyp]

We need:

- windows/ibcxxshim.h
- windows/libcxxshim.modulemap
- windows/libcxxstdlibshim.h

to match what we do for linux . On linux we don't put them under x86_64.

[compnerd]

Oh! I think I know whats happening. swiftlang/swift-installer-scripts#213 was not merged into release/5.9!

[compnerd]

It seems that we aren't packaging libcxxstdlibshims.h on windows, is that supposed to be distributed as well?