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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
31 lines
908 B
Swift
31 lines
908 B
Swift
// RUN: %target-swift-frontend -primary-file %s -O -sil-verify-all -module-name=test -emit-sil | %FileCheck %s
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// REQUIRES: swift_in_compiler
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class C {}
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@_silgen_name("non_barrier")
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@inline(never)
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func non_barrier() {}
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@_silgen_name("borrow")
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@inline(never)
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func borrow(_ c: C)
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// CHECK-LABEL: sil {{.*}}@test_hoist_over_non_barrier : {{.*}} {
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// CHECK: [[INSTANCE:%[^,]+]] = alloc_ref
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// CHECK: [[EI:%.*]] = end_init_let_ref [[INSTANCE]]
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// CHECK: [[BORROW:%[^,]+]] = function_ref @borrow
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// CHECK: apply [[BORROW]]([[EI]])
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// CHECK: strong_release [[EI]]
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// CHECK: [[NON_BARRIER:%[^,]+]] = function_ref @non_barrier
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// CHECK: apply [[NON_BARRIER]]()
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// CHECK-LABEL: } // end sil function 'test_hoist_over_non_barrier'
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@_silgen_name("test_hoist_over_non_barrier")
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func test_hoist_over_non_barrier() {
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let c = C()
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borrow(c)
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non_barrier()
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}
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