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SILGen: Fix invalid SIL emitted when protocol requirement witnessed by base class convenience init #16899

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Merged
merged 1 commit into from
May 30, 2018
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SILGen: Fix invalid SIL emitted when protocol requirement witnessed by base class convenience init #16899

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15 changes: 12 additions & 3 deletions lib/SILGen/SILGenPoly.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3345,11 +3345,20 @@ static WitnessDispatchKind getWitnessDispatchKind(SILDeclRef witness) {
// A natively ObjC method witness referenced this way will end up going
// through its native thunk, which will redispatch the method after doing
// bridging just like we want.
if (isFinal || isExtension || witness.isForeignToNativeThunk()
// Hack--We emit a static thunk for ObjC allocating constructors.
|| (decl->hasClangNode() && witness.kind == SILDeclRef::Kind::Allocator))
if (isFinal || isExtension || witness.isForeignToNativeThunk())
return WitnessDispatchKind::Static;

if (witness.kind == SILDeclRef::Kind::Allocator) {
// Non-required initializers can witness a protocol requirement if the class
// is final, so we can statically dispatch to them.
if (!cast<ConstructorDecl>(decl)->isRequired())
return WitnessDispatchKind::Static;
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What happens if it is marked required (and non-overriding) but the class is also final?

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That should be caught above, where we check for final class or method.

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Oops, of course. Thanks.


// We emit a static thunk for ObjC allocating constructors.
if (decl->hasClangNode())
return WitnessDispatchKind::Static;
}

// Otherwise emit a class method.
return WitnessDispatchKind::Class;
}
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29 changes: 29 additions & 0 deletions test/SILGen/witness-init-requirement-with-base-class-init.swift
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Expand Up @@ -20,3 +20,32 @@ class Dog: Animal, BestFriend {}
// CHECK-LABEL: sil private [transparent] [thunk] @$S4main3DogCAA10BestFriendA2aDP6createxyFZTW
// CHECK: [[SELF:%.*]] = apply
// CHECK: unchecked_ref_cast [[SELF]] : $Animal to $Dog

class Base {
init() {}

convenience init(x: Int) {
self.init()
}
}

protocol Initable {
init(x: Int)
}

final class Derived : Base, Initable {}

// CHECK-LABEL: sil hidden @$S4main4BaseC1xACSi_tcfC : $@convention(method) (Int, @thick Base.Type) -> @owned Base
// CHECK: [[SELF:%.*]] = alloc_ref_dynamic %1 : $@thick Base.Type, $Base
// CHECK: [[METHOD:%.*]] = function_ref @$S4main4BaseC1xACSi_tcfc
// CHECK-NEXT: [[RESULT:%.*]] = apply [[METHOD]](%0, [[SELF]])
// CHECK-NEXT: return [[RESULT]]

// CHECK-LABEL: sil private [transparent] [thunk] @$S4main7DerivedCAA8InitableA2aDP1xxSi_tcfCTW : $@convention(witness_method: Initable) (Int, @thick Derived.Type) -> @out Derived
// CHECK: [[SELF:%.*]] = upcast %2 : $@thick Derived.Type to $@thick Base.Type
// CHECK: [[METHOD:%.*]] = function_ref @$S4main4BaseC1xACSi_tcfC
// CHECK-NEXT: [[RESULT:%.*]] = apply [[METHOD]](%1, [[SELF]])
// CHECK-NEXT: [[NEW_SELF:%.*]] = unchecked_ref_cast [[RESULT]] : $Base to $Derived
// CHECK-NEXT: store [[NEW_SELF]] to [init] %0 : $*Derived
// CHECK-NEXT: [[TUPLE:%.*]] = tuple ()
// CHECK-NEXT: return [[TUPLE]]