[4.1] [Serialization] Handle XREFs to private types #14473
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jrose-apple
commented
Feb 8, 2018
jrose-apple
commented
- Explanation: When the compiler modifies an inlinable function to break apart a struct, and the struct uses a private type for one of its fields, it's possible to end up with a reference to that type across module boundaries. This can happen even in compiler-synthesized code, which results in a regression from Swift 4.0.
- Scope: Affects private types referenced directly or indirectly in inlinable code (including compiler-synthesized code)
- Issue: SR-6874 / rdar://problem/37072260
- Reviewed by: @DougGregor
- Risk: Medium-low. The new code is only used in cases that didn't work before, but it's a little more than trivial.
- Testing: Added compiler regression tests, verified that the original project builds
We can encounter these when the compiler modifies an inlinable function to break apart a struct and the struct uses a private type for one of its fields. It's questionable whether we /should/ handle this, but meanwhile this /is/ a non-intrusive fix that preserves the performance of non-resilient libraries. (That is, it appears this worked in Swift 4.0, though perhaps not all of the same optimizations kicked in.) https://bugs.swift.org/browse/SR-6874 (cherry picked from commit af67204)
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@swift-ci Please test |
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@swift-ci Please nominate |
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