[5.9] Arrange for closure bodies promoted by AllocBoxToStack to have their originals removed by MoveOnlyChecker. #67220
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…ed after specialization." This reverts commit bd5f0a7.
…originals removed by MoveOnlyChecker. This is an improvement of swiftlang#67031 which avoids deleting the closure function body during AllocBoxToStack, which still breaks pass invariants by modifying functions other than the currently-analyzed function. As a function pass, AllocBoxToStack also doesn't really know with certainty whether the original closure function is unused after stack promotion or not. We still want to eliminate the original when it may contain invalid SIL for move-only values that rely on the escape analysis for correct semantics, so rather than mark the original function to be *ignored* during move-only checking, mark it to be *deleted* by move-only checking if the function is in fact unused at that point. If the marked function is still used, we let it pass through move-only checking normally, which may cause redundant diagnostics but is the right thing to do since code is still potentially using the closure with escaping semantics. We should rearrange things to make this situation impossible in the future. rdar://110675352
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@swift-ci Please test |
tbkka
approved these changes
Jul 11, 2023
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Issue: rdar://110675352
• Explanation: Removes a source of potential compiler crashes when noncopyable types are captured in nonescaping closures. This is an improvement on the approach taken in #67035 that avoids breaking SIL pass manager invariants and possibly leading to other compiler crashes.
• Scope of Issue: Crash-on-valid.
• Origination: Noncopyable types feature work.
• Risk: Low. The patch deletes SIL that is unreachable from the rest of the program so should have no runtime effect.
• Reviewed By: @atrick, @eeckstein
• Automated Testing: Swift CI
• Dependencies: None
• Builder Impact: Not applicable
• Directions for QE: None