MoveOnlyChecker: avoid dangling reference in custom alloc #84934
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The AvailableValueStore maintains stable spans of SILValues, one span (effectively a MutableArrayRef) per basic block, that is preallocated for performance. This patch fixes an issue where _a pointer_ to a span is vended from `AvailableValueStore::get` and that pointer is into storage within a DenseMap, which can reallocate and invalidate all such pointers. There's no reason to be returning a pointer to a MutableArrayRef, aka AvailableValues, so I've simply stripped off that indirection to fix this issue. resolves rdar://162440304
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jckarter
approved these changes
Oct 15, 2025
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The AvailableValueStore maintains stable spans of SILValues, one span (effectively a MutableArrayRef) per basic block, that is preallocated for performance.
This patch fixes an issue where a pointer to a span is vended from
AvailableValueStore::getand that pointer is into storage within a DenseMap, which can reallocate and invalidate all such pointers.There's no reason to be returning a pointer to a MutableArrayRef, aka AvailableValues, so I've simply stripped off that indirection to fix this issue.
resolves rdar://162440304