SwiftWasm 5.4 release

[MaxDesiatov]

This is a tracking issue for everything that could block the 5.4 release of SwiftWasm.

• Compiler > 5.3.1 crashes when building Tokamak #2851 - failure to build Tokamak with 5.4 snapshots.
• UUID() does not produce proper UUIDs #3320
• Set up testing with 5.4 snapshots in the JavaScriptKit repository. Test with multiple toolchain versions JavaScriptKit#135
• Set up testing with 5.4 snapshots in the Tokamak repository. Bump requirements to Swift 5.4, migrate to @resultBuilder TokamakUI/Tokamak#442
• Fix Foundation autolinking issues
• Enable LTO for the repositories above?
• Enable LTO by default or expose via flags in carton?

[MaxDesiatov]

@kateinoigakukun could you clarify what's the status of LTO in the 5.4 branch?

[kateinoigakukun]

LTO is already available in 5.4 branch but not tested well.

[SDGGiesbrecht]

A month has passed. Is there still an intention to release for 5.4?

[MaxDesiatov]

Yes, of course that's still the intention. I haven't been able to fix the regression we see with our 5.4 snapshots though, specifically #2851. If anyone can help, I would greatly appreciate it.

[SDGGiesbrecht]

Unfortunately it looks over my head. But my gut tells me the implementation of SE‐0284—which was added between 5.3.1 and 5.4—may have something to do with it.

[MaxDesiatov]

The regression is fixed now. I'm thinking of tagging swift-wasm-5.4-SNAPSHOT-2021-08-08-a as 5.4.0. Any objections?

[MaxDesiatov]

I'm seeing issues with linking Foundation when building with SwiftPM with 5.4.0, I removed the 5.4.0-RELEASE tag for now

wasm-ld: error: /Library/Developer/Toolchains/swift-wasm-5.4.0-RELEASE.xctoolchain
/usr/lib/swift_static/wasi/libFoundation.a(Data.swift.obj): undefined symbol: _NSConcreteStackBlock
wasm-ld: error: /Library/Developer/Toolchains/swift-wasm-5.4.0-RELEASE.xctoolchain
/usr/lib/swift_static/wasi/libFoundation.a(Data.swift.obj): undefined symbol: _Block_copy
wasm-ld: error: /Library/Developer/Toolchains/swift-wasm-5.4.0-RELEASE.xctoolchain
/usr/lib/swift_static/wasi/libFoundation.a(Data.swift.obj): undefined symbol: _Block_release
wasm-ld: error: /Library/Developer/Toolchains/swift-wasm-5.4.0-RELEASE.xctoolchain
/usr/lib/swift_static/wasi/libFoundation.a(Date.swift.obj): undefined symbol: CFAbsoluteTimeGetCurrent
wasm-ld: error: /Library/Developer/Toolchains/swift-wasm-5.4.0-RELEASE.xctoolchain
/usr/lib/swift_static/wasi/libFoundation.a(Date.swift.obj): undefined symbol: CFAbsoluteTimeGetCurrent
wasm-ld: error: /Library/Developer/Toolchains/swift-wasm-5.4.0-RELEASE.xctoolchain
/usr/lib/swift_static/wasi/libFoundation.a(Date.swift.obj): undefined symbol: CFAbsoluteTimeGetCurrent
wasm-ld: error: /Library/Developer/Toolchains/swift-wasm-5.4.0-RELEASE.xctoolchain
/usr/lib/swift_static/wasi/libFoundation.a(Date.swift.obj): undefined symbol: CFAbsoluteTimeGetCurrent
...

@kateinoigakukun could this be caused by autolinking changes applied to the toolchain, but not Foundation, or vice versa?

As far as I understand, the issue can also be seen in swift-wasm-5.4-SNAPSHOT-2021-08-08-a, from which I've tagged that broken 5.4.0 I removed.

[kateinoigakukun]

@MaxDesiatov My auto-linking stuff is not included in 5.4 at all. So users still need to explicitly import CoreFoundation.
If we include them in 5.4, it would make the diff from the upstream bigger, so I want to avoid cherry-pick in our fork.

[MaxDesiatov]

That would only make the diff of swiftwasm-release/5.4 against upstream release/5.4 bigger, right? I thought we only cared about the size of swiftwasm against main, or am I missing something?

[kateinoigakukun]

That would only make the diff of swiftwasm-release/5.4 against upstream release/5.4 bigger, right?

Yes, -public-autolink option can be used by toolchain users, so it introduces an incompatibility with swiftwasm-release/5.4 and release/5.4. I'm worried about not source code diff but feature diff.

[MaxDesiatov]

Would a simple @_exported import CoreFoundation in the 5.4 branch of our fork of Foundation fix the issue? Or is this not enough for the linker to infer things correctly?

[kateinoigakukun]

No need @_exported but just import CoreFoundation is enough as a short-term solution, I think.