Cross-compiling packages which contain macros doesn't work

[finagolfin]

Description

@woxiang04 reported in the forum that they couldn't cross-compile the macro examples, and @neonichu said that doesn't work yet. I am unsure what this entails, as presumably the official Swift 5.9 toolchain for macOS can cross-compile code with macros for iOS?

I have not tried this myself, just reporting that error from the forum.

Expected behavior

Macros to work when cross-compiling a package

Actual behavior

According to that forum thread:

compiler plugin not loaded: /data/Downloads/swift-macro-examples/.build/aarch64-unknown-linux-android24/debug/MacroExamplesPlugin; loader error: Exec format error

Steps to reproduce

1. Build the Swift macro examples with a cross-compilation SDK

Swift Package Manager version/commit hash

5.9

Swift & OS version (output of swift --version ; uname -a)

5.9 for Ubuntu 20.04 x86_64 cross-compiling to Android AArch64

[neonichu]

That's correct, macros are not expected to work when cross-compiling today (that's not limited to any particular platform).

[finagolfin]

Should be reopened as this is still being worked on, #7353.