Cannot cross-compile example to x86_64 on Apple Silicon

[pthexton]

Hey all,

Can somebody please point me in the right direction here.. we're intending to make use of SwiftRs in one of our projects to avoid duplicating implementation for a specific shared functionality between apps where we have a pre-existing implementation in Swift. We currently need to distribute our apps as a universal binary.

Unfortunately, when attempting to build a universal binary I've discovered that something has gone wrong at the linker stage and I get an error related to not being able to load @rpath/libswiftCore.dylib

To make sure I hadn't done anything wrong, I've grabbed the example from this repo and I am seeing the same behaviour. Compiling and running the example natively on my Apple Silicon Mac works as expected, but when I compile for x86_64 architecture things don't work. Compile command in this case is cargo build --target x86_64-apple-darwin

  $ target/x86_64-apple-darwin/debug/example
dyld[31266]: Library not loaded: @rpath/libswiftCore.dylib
  Referenced from: <7923220E-4AA3-3374-AAC3-53D979383A00> /<snipped>/swift-rs-main/example/target/x86_64-apple-darwin/debug/example
  Reason: no LC_RPATH's found
zsh: abort      target/x86_64-apple-darwin/debug/example

I can modify the resulting binary by adding an rpath for /usr/lib/swift by doing install_name_tool -add_rpath /usr/lib/swift target/x86_64-apple-darwin/debug/example, then then results in the binary running as expected

$ target/x86_64-apple-darwin/debug/example
length of base64 encoded thumbnail: 1054264
First Volume Name: Macintosh HD
function returned nil: true
function returned data: true

But this doesn't feel like the "correct" solution to me.

Any help/advise greatly appreciated.

[pthexton]

I should note that I have seen the mention of Tauri .... but we're not using that, and I'm unaware of how the tauri build system sets the build environment to correct this when the documented option is set appropriately.

[pthexton]

If it helps anyone else, I've found a better solution than using install_name_tool by instead putting the following in my build.rs

println!("cargo:rustc-link-arg=-Wl,-rpath,/usr/lib/swift");

I'm still not sure why things are being linked with @rpath in the first place though, would be nice if swift-rs knew to do that already when linking if possible.