Remove Stubs.cpp and reimplement what it has in Swift. #929
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This PR removes Stubs.cpp, which currently houses some thunks for functions that are conditionally unavailable in glibc, and replaces it with runtime function lookups in Swift. Is there potentially a one-time non-zero performance cost? Yes. Is that performance cost prohibitive given that the functions are only looked up once and then cached? No. These functions won't get called on Linux if `SWT_NO_DYNAMIC_LINKING` is defined but we don't currently support that combination anyway. Even if you're using a statically-linked Swift standard library, we'd expect Linux to still support calling `dlsym()`.
grynspan added linux grynspan requested review from SeanROlszewski, briancroom, stmontgomery and suzannaratcliff as code owners 
| @swift-ci test |
| @swift-ci test |
briancroom approved these changes Jan 27, 2025
stmontgomery approved these changes Jan 27, 2025
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This PR removes Stubs.cpp, which currently houses some thunks for functions that are conditionally unavailable in glibc, and replaces it with runtime function lookups in Swift. Is there potentially a one-time non-zero performance cost? Yes. Is that performance cost prohibitive given that the functions are only looked up once and then cached? No.
These functions won't get called on Linux if
SWT_NO_DYNAMIC_LINKINGis defined but we don't currently support that combination anyway. Even if you're using a statically-linked Swift standard library, we'd expect Linux to still support callingdlsym().Checklist: