Package 'Echo' build failing with undefined symbols when using swift-create-xcframework

Using Swift
, ,
1

Links to swift-create-xcframework, the package I'm building, and Echo. If you're not familiar with Echo, it's a super cool package for Swift reflection written by Apple's very own @Alejandro!

The missing symbols are all part of the Swift core library, I think. Stuff like the type metadata for Builtin.RawPointer, or internal functions like registerProtocolConformances . I'm not sure why these would fail to link unless swift-create-xcframework was leaving out an important compiler flag.

I can't actually attach a file including the compile commands (they're very long, is pasting long compiler commands here normal? I'd hate that…) so I've asked ChatGPT highlight the major differences in the two CompileC commands for KnownMetadata.c (where most of the errors are) and diagnose the error, which you can read here. What do you think is the most likely culprit?

xcodebuild command that succeeds:

xcodebuild -scheme Jsum -destination 'platform=iOS' build

swift-create-xcframework command that fails:

swift create-xcframework \
    --platform ios \
    --xc-setting IPHONEOS_DEPLOYMENT_TARGET=12.0 \
    --configuration debug

Truncated error:

Undefined symbols for architecture arm64:
  … // dozen other symbols
  "type metadata for Builtin.RawPointer", referenced from:
      _getBuiltinRawPointerMetadata in KnownMetadata.o
  "type metadata for Builtin.Word", referenced from:
      _getBuiltinWordMetadata in KnownMetadata.o
  "_registerProtocolConformances", referenced from:
      __loadImageFunc in ImageInspectionMachO.o
  "_registerProtocols", referenced from:
      __loadImageFunc in ImageInspectionMachO.o
  "_registerTypeMetadata", referenced from:
      __loadImageFunc in ImageInspectionMachO.o
ld: symbol(s) not found for architecture arm64
2

Without any further attention, do you still get the same errors if you change the deployment target to iOS 13, or even 12.2? That's when Swift shipped with the Apple OSs, and it's the simplest thing I can think of that might not be accounted for in whatever swift-create-xcframework layered on top of SwiftPM and xcodebuild.

3

That's a good catch! But no dice :(