Buildbot_iphoneos_arm64_crosscompiler preset broken on swift 5.2.4

It seems that at a certain point (no backtrace is provided to the user) it just tries to:

-- Build files have been written to: /Users/minuscorp/Documents/GitHub/build/LLVMClangSwift_iphoneos/swift-macosx-x86_64
+ popd
+ /usr/local/bin/cmake --build /Users/minuscorp/Documents/GitHub/build/LLVMClangSwift_iphoneos/swift-macosx-x86_64 -- -j12 all swift-test-stdlib-macosx-x86_64
ninja: error: unknown target 'swift-test-stdlib-macosx-x86_64'
./swift/utils/build-script: fatal error: command terminated with a non-zero exit status 1, aborting
./swift/utils/build-script: fatal error: command terminated with a non-zero exit status 1, aborting

And that's all. Maybe the preset is outdated and need an update. It is important to us to have toolchains that can be used on devices (due to certain limitations).

Any sugestion?

It is not clear what you hope to do with that. It was supposed to cross-compile the Swift compiler itself to run on iOS (it doesn't actually produce a cross-compiler and is mislabeled) without the stdlib, but has probably gone out of date. What do you expect to do with it?

Actually I need a toolchain that is able to compile into real devices. For example now I need to debug with the Swift 5.2.4 an app but in an iOS 14 device. Due to lack of module stability I hehe to stick with Swift 5.2.4 but if I install that toolchain it prompts to me that toolchains are not meant to be used in a real device, that only should be accomplished with a toolchain that only contains the compiler (and I guess more componentes) that's why I need it, but there's no documentation for this anywhere.

Heh, I don't know what that means. Let's try this: normally, you write Swift and build it with a Swift compiler on a macOS host to run on the same computer. If you write an iOS app, you compile from a macOS host to an iOS target.

What is the host you want to run the Swift compiler on and the target you want to run your own software on? Is your host iOS, ie you want to run the compiler on iOS itself? I believe Apple has restrictions against that, but I don't know the details.

As far as Xcode 12 prompts, you have to provide a Swift compiler which has as target iOS on arm64 architectures (real devices). That was the purpose of that preset originally, but doesn't work anymore, but yeah, long story short I need an old compiler on a new iOS version running so I'm able to debug and install it using Swift 5.2.4 and not the 5.3 beta (which forces me to update dependencies that still does not allow that version).

It sounds like you simply want a Swift 5.2.4 compiler running on a macOS host and targeting iOS 14. I know nothing about targeting different iOS versions, but I can tell you that build preset has nothing to do with what you want.

I don't believe cross-compiling the Swift corelibs for iOS is open source, so you can't do what you want yourself.