[cxx-interop][IRGen] Emit type metadata accessors correctly #74208
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@swift-ci please test |
egorzhdan
commented
Jun 7, 2024
| @@ -1102,9 +1102,6 @@ MetadataAccessStrategy irgen::getTypeMetadataAccessStrategy(CanType type) { | |||
| assert(type->hasUnboundGenericType()); | |||
| } | |||
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| if (type->isForeignReferenceType()) | |||
| return MetadataAccessStrategy::PublicUniqueAccessor; | |||
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| if (requiresForeignTypeMetadata(nominal)) | |||
| return MetadataAccessStrategy::ForeignAccessor; | |||
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This is what needs to be returned for a C++ reference type.
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I see. We were lazily emitting the type metadata when we first referenced in, but we were emitting it with strong linkage? Yes, this is the right fix, then.
This change makes sure we correctly emit IR for type metadata accessors for C++ reference types. This fixes linker errors when a type metadata of a C++ reference type is used in multiple object files that are later linked together, for instance, if a C++ reference type is conformed to different Swift protocols in different Swift source files: ``` duplicate symbol 'type metadata accessor for __C.SharedObject' in: main.o second.o ld: 1 duplicate symbols ``` rdar://129027705
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@swift-ci please smoke test |
rjmccall
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Jun 7, 2024
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…-metadata-accessor [cxx-interop][IRGen] Emit type metadata accessors correctly
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…-metadata-accessor [cxx-interop][IRGen] Emit type metadata accessors correctly
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…-metadata-accessor [cxx-interop][IRGen] Emit type metadata accessors correctly
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This change makes sure we correctly emit IR for type metadata accessors for C++ reference types.
This fixes linker errors when a type metadata of a C++ reference type is used in multiple object files that are later linked together, for instance, if a C++ reference type is conformed to different Swift protocols in different Swift source files:
rdar://129027705