[cxx-interop] Synthesize a deprecated zero initializer for C++ structs #66220
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egorzhdan
commented
May 30, 2023
| @@ -2379,11 +2379,30 @@ namespace { | |||
| hasMemberwiseInitializer = false; | |||
| } | |||
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| if (hasZeroInitializableStorage && !cxxRecordDecl) { | |||
| if (hasZeroInitializableStorage && | |||
| !(cxxRecordDecl && cxxRecordDecl->hasDefaultConstructor())) { | |||
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I wonder if we should limit this to C-looking C++ structs, e.g. those without base classes / templated parameters / etc.
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@swift-ci please smoke test |
When importing a C header in the C++ language mode, Clang/Swift treat C structs as C++ structs. Currently Swift synthesizes a default initializer that zero-initializes the backing memory of the struct for C structs, but not for C++ structs. This is causing issues in existing projects that use C libraries and rely on having the default initializer available in Swift. This change enables the synthesis of a default initializer for C++ structs. Since many C++ structs are not designed to be initialized this way, the initializer is marked as deprecated in Swift. rdar://109727620
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@swift-ci please smoke test |
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@swift-ci please smoke test macOS |
zoecarver
approved these changes
May 31, 2023
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When importing a C header in the C++ language mode, Clang/Swift treat C structs as C++ structs.
Currently Swift synthesizes a default initializer that zero-initializes the backing memory of the struct for C structs, but not for C++ structs.
This is causing issues in existing projects that use C libraries and rely on having the default initializer available in Swift. This change enables the synthesis of a default initializer for C++ structs. Since many C++ structs are not designed to be initialized this way, the initializer is marked as deprecated in Swift.
rdar://109727620