Use the remaining half bit in the refcount to bypass ObjC deallocation overhead #25418
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stdlib/public/SwiftShims/RefCount.h
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| //Immortal and no objc complications share a bit, so don't let setting | ||
| //the complications one clear the immmortal one | ||
| if (oldbits.isImmortal(true) || oldbits.pureSwiftDeallocation() == nonobjc){ | ||
| assert(!oldbits.hasSideTable()) |
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This is new from the previous change, at @jrose-apple's suggestion
stdlib/public/runtime/HeapObject.cpp
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| } | ||
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| static void _interpose_objc_association(void *ctxt) { | ||
| if (__builtin_available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *))) { |
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This is new, and I've verified that it compiles to nothing when targeting the listed OSs, so the in-OS build shouldn't see any overhead from it.
| } | ||
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| LLVM_ATTRIBUTE_ALWAYS_INLINE | ||
| void setIsImmortal(bool value) { | ||
| setField(IsImmortal, value); | ||
| assert(value); |
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This switch only flips one way, so we assert that now
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Need a compiler-rt fix; it's currently only building for Intel in Swift CI |
…ObjC deallocation overhead"" And add availability checking for back deployment This reverts commit 817ea12.
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I'm told that the linux failures are irregular and were seen this morning, gonna retry |
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@swift-ci clean test Linux |
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We can use the new setAssociatedObject interposition function to make this safe. 1.1-1.5x win on a huge variety of benchmarks.
#ifdef'd out for platforms that don't have the new interposition function, and guarded with __builtin_available so it'll back-deploy
Fixes rdar://36825362