[Linux] Enable build-ids.

[al45tair]

We should use build IDs on Linux so that we can identify the built artefacts, and also so that we can match them up with debug information should we choose to separate it.

rdar://130582768

[jmschonfeld]

Overall the change looks good to me!

Since we don't have CI setup on this branch yet, I used my other WIP PRs to kick off this linux test which includes this PR: https://ci.swift.org/job/swift-PR-Linux/16070/. Let's wait for that to pass before merging (Linux is in the state where swift-ci testing should pass).

Do we also need to do the same for all of the dependencies (swift-foundation, swift-foundation-icu, and swift-collections)?

[al45tair]

Do we also need to do the same for all of the dependencies (swift-foundation, swift-foundation-icu, and swift-collections)?

👍 Yes, ideally, anything that is installed as a .so or that produces an executable on Linux would have --build-id=sha1 as a linker option, so that we get build IDs on everything (like we have on Apple platforms by default). It isn't necessary for static libraries.

[jmschonfeld]

I'm seeing some build failures that appear to be new with this change:

(.data.rel.ro+0x330): error: undefined reference to '$s22_FoundationCollections4RopeV8_StorageCMn'
/home/build-user/build/buildbot_linux/none-swift_package_sandbox_linux-x86_64/usr/lib/swift_static/linux/libFoundationEssentials.a(AttributedString+_InternalRuns.swift.o)(.data.rel.ro+0x338): error: undefined reference to '$s22_FoundationCollections4RopeV5_NodeVMn'

This symbol should be exported from lib_FoundationCollections.a which is auto linked from libFoundationEssentials.a:

target_compile_options(FoundationEssentials PRIVATE
        "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xfrontend -public-autolink-library -Xfrontend _FoundationCollections>")

Is it possible that this change introduced that issue?

[jmschonfeld]

Oh I apologize, that was due to an issue on my end. New test run kicked off at https://ci.swift.org/job/swift-PR-Linux/16085/

[jmschonfeld]

Ok the new linux test passed so this looks good to me, thanks!