Linux packages fail to build with LLVM 18 and Apple 2023 versions of clang #7241
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Sources/Build/BuildDescription/ClangTargetBuildDescription.swift
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There's some chance here that is would break older packages which rely on the existing behavior, but it doesn't seem that likely that there's code that requires modules in C-based targets. Unfortunately, the compatibility suite is only for macOS AFAIK (cc @shahmishal). Do we need any way for package authors to opt-in to modules? They can do so via unsafe flags, but that comes with restrictions on the use of their packages. |
We do support Linux source compat suite - |
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Thanks, Mishal, I didn't know that! We should test this PR with those jobs to see if there's impact. |
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Awesome, @shahmishal how do I invoke those suites with this change? Or do I just need to land it and someone will yell at me if they break? |
…clang Newer versions of clang add builtin modules for its C Standard Library headers. This creates problems* when building with a single module map that tries to absorb all of the OS/SDK dependencies, which is what all non-Apple platforms currently do in SPM. This works for Swift targets because the Swift compiler injects module maps via vfs for non-Apple platforms. However, clang doesn't do anything similar for C-based targets, and so they fail to build. For now, don't build with modules for any SPM C-based targets on non-Apple platforms. * Some problems are module cycles and headers being absorbed into unexpected modules. clang modules generally expect that OS/SDK headers are covered by module maps, and _not_ absorbed into whatever module happens to include them first. rdar://120716498
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@swift-ci smoke test |
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@swift-ci test |
Newer versions of clang add builtin modules for its C Standard Library headers. This creates problems* when building with a single module map that tries to absorb all of the OS/SDK dependencies, which is what all non-Apple platforms currently do in SwiftPM.
This works for Swift targets because the Swift compiler injects module maps via vfs for non-Apple platforms. However, clang doesn't do anything similar for C-based targets, and so they fail to build.
For now, don't build with modules for any SwiftPM C-based targets on non-Apple platforms.
* Some problems are module cycles and headers being absorbed into unexpected modules. clang modules generally expect that OS/SDK headers are covered by module maps, and not absorbed into whatever module happens to include them first.
rdar://120716498