[cxx-interop] Improve performance of synthesized iterator conformances #84853
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egorzhdan
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@swift-ci please test |
Xazax-hun
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Nice finding, Egor! |
etcwilde
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When conforming a C++ iterator type to the `UnsafeCxxInputIterator` protocol, we try to instantiate `operator==` for the given type, which is one of the requirements of the protocol. The logic that did name lookup was unintentionally running a global lookup for `==` across all of the visible Clang modules, which became a performance issue. This happened because ClangImporter was doing a name lookup in the fake `__ObjC` module instead of the actual owning Clang module for the iterator type. rdar://162125326 / resolves swiftlang#84733
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This depends on #84877 |
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@swift-ci please benchmark macOS |
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When conforming a C++ iterator type to the
UnsafeCxxInputIteratorprotocol, we try to instantiateoperator==for the given type, which is one of the requirements of the protocol.The logic that did name lookup was unintentionally running a global lookup for
==across all of the visible Clang modules, which became a performance issue. This happened because ClangImporter was doing a name lookup in the fake__ObjCmodule instead of the actual owning Clang module for the iterator type.rdar://162125326 / resolves #84733