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Augusto Noronha
8307fe17e4
A protocol's constraint decides the layout of an existential of it: a class-constrained existential is a reference plus witness tables, while an opaque one also has an inline buffer and a metadata pointer. Without reflection metadata, there's no way to tell which case a protocol is, so we need to encode it in DWARF. Assisted-by: claude
28 lines
1.1 KiB
Swift
28 lines
1.1 KiB
Swift
// RUN: %target-swift-frontend %s -emit-ir -g -o - | %FileCheck %s
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class Base {}
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protocol Opaque {}
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protocol AnyObjectBound: AnyObject {}
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protocol SuperclassBound: Base {}
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class C: Opaque, AnyObjectBound {}
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class D: Base, SuperclassBound {}
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func f() {
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let opaque: any Opaque = C()
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let anyObjectBound: any AnyObjectBound = C()
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let superclassBound: any SuperclassBound = D()
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}
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// Both a class constraint spelled as AnyObject and one implied by a superclass
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// requirement are annotated, and share the annotation.
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// CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "AnyObjectBound"{{.*}}annotations: ![[ANNOT:[0-9]+]]
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// CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "SuperclassBound"{{.*}}annotations: ![[ANNOT]]
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// CHECK-DAG: ![[ANNOT]] = !{![[ENTRY:[0-9]+]]}
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// CHECK-DAG: ![[ENTRY]] = !{!"swift.ClassConstrainedProtocol", i1 true}
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// An unconstrained protocol carries no annotation, which is what gives it the
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// plain Protocol field descriptor kind.
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// CHECK-DAG: !DICompositeType(tag: DW_TAG_structure_type, name: "Opaque"{{.*}}identifier: "{{.*}}6Opaque_pD")
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