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Deinit-Devirtualization: fix a crash when trying to de-virtualize a non-copyable generic #74474

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Merged
merged 1 commit into from
Jun 17, 2024
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Deinit-Devirtualization: fix a crash when trying to de-virtualize a non-copyable generic #74474

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6 changes: 5 additions & 1 deletion SwiftCompilerSources/Sources/Optimizer/Utilities/Devirtualization.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,11 @@ private func devirtualize(destroy: some DevirtualizableDestroy, _ context: some
if !type.isMoveOnly {
return true
}
precondition(type.isNominal, "non-copyable non-nominal types not supported, yet")

if !type.isNominal {
// E.g. a non-copyable generic function parameter
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This comment confuses me. Is a Copyable generic parameter “nominal”?

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I mean, e.g. func foo<T: ~Copyable>(_ t: T). T is not copyable and not a nominal type

return true
}

let result: Bool
if type.nominal.hasValueDeinit && !destroy.shouldDropDeinit {
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10 changes: 10 additions & 0 deletions test/SILOptimizer/devirt_deinits.sil
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Expand Up @@ -273,6 +273,16 @@ bb0(%0 : $*S4):
return %r : $()
}

// CHECK-LABEL: sil [ossa] @nonCopyable_generic :
// CHECK: destroy_addr %0
// CHECK: } // end sil function 'nonCopyable_generic'
sil [ossa] @nonCopyable_generic : $@convention(thin) <T where T : ~Copyable> (@in T) -> () {
bb0(%0 : $*T):
destroy_addr %0 : $*T
%r = tuple ()
return %r : $()
}

sil @s1_deinit : $@convention(method) (@owned S1) -> ()
sil @s2_deinit : $@convention(method) (@owned S2) -> ()
sil @s3_deinit : $@convention(method) <T> (@in S3<T>) -> ()
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