6.0: [MoveOnlyAddressChecker] Fix enum representation. #72508
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The visitor returns false to indicate an unknown/unhandled instruction. Previously it returned true as a fallback. This resulted in aberrant behavior: e.g., in the test case committed here, the try_apply was deleted.
The implementation of isUsableFromInline asserts that the function not be public, so check that it's not before calling it.
Treat a take of a copyable value as a take.
Change FieldSensitive's enum representation to allow distinguishing among the elements with associated value. Consider `unchecked_take_enum_data_addr` to consume all other fields than that taken. rdar://125113258
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@swift-ci please test |
tbkka
approved these changes
Mar 22, 2024
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Explanation: Fix a class of compiler crashes by teaching the move-only address checker to represent the elements of an enum.
The checker and its supporting infrastructure (FieldSensitivePrunedLiveness) track the indecomposable fields of an aggregate individually, checking that each which is non-copyable is consumed exactly once. Among other things, it uses this infrastructure to determine whether a node of the aggregate may be consumed on its own (which is not allowed if the node appears within an intermediary aggregate with a deinit). (In the future, it might be allowed so long as that intermediary aggregate had been
discard'd.)To allow this walk, it's necessary to identify which case of an enum is being consumed. (For example, one element but not another might have a payload with a deinit.)
Previously, the tracking for the indecomposable fields of an enum used the same bits to represent the different enum elements. That obstructed the walk up the tree from the consumed node.
Here, this is fixed by tracking the elements of an enum separately.
Scope: Affects move-only checking.
Issue: rdar://125113258
Original PR: #72469
Risk: Low.
Testing: Added test case that previously resulted in a crash.
Reviewer: Joe Groff ( @jckarter )