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5bc036661c
It lowers let property accesses of classes.
Lowering consists of two tasks:
* In class initializers, insert `end_init_let_ref` instructions at places where all let-fields are initialized.
This strictly separates the life-range of the class into a region where let fields are still written during
initialization and a region where let fields are truly immutable.
* Add the `[immutable]` flag to all `ref_element_addr` instructions (for let-fields) which are in the "immutable"
region. This includes the region after an inserted `end_init_let_ref` in an class initializer, but also all
let-field accesses in other functions than the initializer and the destructor.
This pass should run after DefiniteInitialization but before RawSILInstLowering (because it relies on `mark_uninitialized` still present in the class initializer).
Note that it's not mandatory to run this pass. If it doesn't run, SIL is still correct.
Simplified example (after lowering):
bb0(%0 : @owned C): // = self of the class initializer
%1 = mark_uninitialized %0
%2 = ref_element_addr %1, #C.l // a let-field
store %init_value to %2
%3 = end_init_let_ref %1 // inserted by lowering
%4 = ref_element_addr [immutable] %3, #C.l // set to immutable by lowering
%5 = load %4
98 lines
2.6 KiB
Swift
98 lines
2.6 KiB
Swift
// RUN: %target-swift-frontend -Xllvm -sil-full-demangle -O -emit-sil -primary-file %s | %FileCheck %s
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//
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// This is a .swift test because the SIL parser does not support Self.
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// Do not inline C.factory into main. Doing so would lose the ability
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// to materialize local Self metadata.
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// REQUIRES: swift_in_compiler
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class C {
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required init() {}
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}
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class SubC : C {}
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var g: AnyObject = SubC()
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@inline(never)
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func gen<R>() -> R {
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return g as! R
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}
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extension C {
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@inline(__always)
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class func factory(_ z: Int) -> Self {
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return gen()
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}
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}
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// Call the function so it can be inlined.
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var x = C()
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var x2 = C.factory(1)
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@inline(never)
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func callIt(fn: () -> ()) {
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fn()
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}
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protocol Use {
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func use<T>(_ t: T)
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}
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var user: Use? = nil
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class BaseZ {
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final func baseCapturesSelf() -> Self {
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let fn = { [weak self] in _ = self }
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callIt(fn: fn)
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return self
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}
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}
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// Do not inline C.capturesSelf() into main either. Doing so would lose the ability
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// to materialize local Self metadata.
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class Z : BaseZ {
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@inline(__always)
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final func capturesSelf() -> Self {
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let fn = { [weak self] in _ = self }
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callIt(fn: fn)
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user?.use(self)
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return self
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}
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// Inline captureSelf into callCaptureSelf,
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// because their respective Self types refer to the same type.
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final func callCapturesSelf() -> Self {
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return capturesSelf()
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}
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final func callBaseCapturesSelf() -> Self {
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return baseCapturesSelf()
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}
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}
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_ = Z().capturesSelf()
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// CHECK-LABEL: sil {{.*}}@main : $@convention(c)
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// CHECK: function_ref static inline_self.C.factory(Swift.Int) -> Self
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// CHECK: [[F:%[0-9]+]] = function_ref @$s11inline_self1CC7factory{{[_0-9a-zA-Z]*}}FZ : $@convention(method) (Int, @thick C.Type) -> @owned C
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// CHECK: apply [[F]](%{{.+}}, %{{.+}}) : $@convention(method) (Int, @thick C.Type) -> @owned C
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// CHECK: [[Z:%.*]] = alloc_ref $Z
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// CHECK: [[C:%.*]] = upcast [[Z]]
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// CHECK: [[EI:%.*]] = end_init_let_ref [[C]]
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// CHECK: [[DC:%.*]] = unchecked_ref_cast [[EI]]
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// CHECK: function_ref inline_self.Z.capturesSelf() -> Self
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// CHECK: [[F:%[0-9]+]] = function_ref @$s11inline_self1ZC12capturesSelfACXDyF : $@convention(method) (@guaranteed Z) -> @owned Z
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// CHECK: apply [[F]]([[DC]]) : $@convention(method) (@guaranteed Z) -> @owned
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// CHECK: return
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// CHECK-LABEL: sil hidden @$s11inline_self1ZC16callCapturesSelfACXDyF : $@convention(method)
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// CHECK-NOT: function_ref @$s11inline_self1ZC12capturesSelfACXDyF :
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// CHECK: }
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// CHECK-LABEL: sil hidden {{.*}}@$s11inline_self1ZC20callBaseCapturesSelfACXDyF
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// CHECK-NOT: function_ref @$s11inline_self5BaseZC16baseCapturesSelfACXDyF :
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// CHECK: }
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