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[cxx-interop] Use a synthesized C++ method when accessing a base field or subscript from a derived class synthesized method
The use of a synthesized C++ method allows us to avoid making a copy of self when accessing the base field or subscript from Swift
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15 files changed

+596
-90
lines changed

15 files changed

+596
-90
lines changed

‎lib/ClangImporter/ClangImporter.cpp‎

Lines changed: 235 additions & 38 deletions
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‎test/Interop/Cxx/class/inheritance/Inputs/fields.h‎

Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -66,3 +66,37 @@ struct ClassTemplate {
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};
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struct DerivedFromClassTemplate : ClassTemplate<int> {};
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int &getCopyCounter() {
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static int copyCounter = 0;
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return copyCounter;
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}
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class CopyTrackedBaseClass {
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public:
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CopyTrackedBaseClass(int x) : x(x) {}
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CopyTrackedBaseClass(const CopyTrackedBaseClass &other) : x(other.x) {
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++getCopyCounter();
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}
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int x;
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};
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class CopyTrackedDerivedClass: public CopyTrackedBaseClass {
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public:
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CopyTrackedDerivedClass(int x) : CopyTrackedBaseClass(x) {}
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};
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class NonEmptyBase {
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public:
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int getY() const {
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return y;
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}
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private:
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int y = 11;
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};
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class CopyTrackedDerivedDerivedClass: public NonEmptyBase, public CopyTrackedDerivedClass {
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public:
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CopyTrackedDerivedDerivedClass(int x) : CopyTrackedDerivedClass(x) {}
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};

‎test/Interop/Cxx/class/inheritance/Inputs/module.modulemap‎

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Original file line numberDiff line numberDiff line change
@@ -15,6 +15,10 @@ module SubTypes {
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header "sub-types.h"
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}
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module Subscripts {
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header "subscripts.h"
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}
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module TypeAliases {
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header "type-aliases.h"
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}

test/Interop/Cxx/foreign-reference/Inputs/function-inheritance.h renamed to test/Interop/Cxx/class/inheritance/Inputs/subscripts.h

Lines changed: 38 additions & 24 deletions
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,3 @@
1-
#pragma once
2-
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#define FRT \
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__attribute__((swift_attr("import_reference"))) \
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__attribute__((swift_attr("retain:immortal"))) \
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__attribute__((swift_attr("release:immortal")))
7-
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int &getCopyCounter() {
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static int copyCounter = 0;
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return copyCounter;
@@ -17,25 +10,17 @@ class CopyTrackedBaseClass {
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++getCopyCounter();
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}
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int getX() const {
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return x;
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int operator [](int y) const {
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return y + x;
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}
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private:
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int x;
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} FRT;
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};
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class CopyTrackedDerivedClass: public CopyTrackedBaseClass {
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public:
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CopyTrackedDerivedClass(int x) : CopyTrackedBaseClass(x) {}
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int getDerivedX() const {
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return getX();
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}
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} FRT;
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CopyTrackedDerivedClass *makeCopyTrackedDerivedClass(int x) {
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return new CopyTrackedDerivedClass(x);
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}
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};
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class NonEmptyBase {
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public:
@@ -44,13 +29,42 @@ class NonEmptyBase {
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}
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private:
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int y = 11;
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} FRT;
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};
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class CopyTrackedDerivedDerivedClass: public NonEmptyBase, public CopyTrackedDerivedClass {
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public:
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CopyTrackedDerivedDerivedClass(int x) : CopyTrackedDerivedClass(x) {}
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} FRT;
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};
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CopyTrackedDerivedDerivedClass *makeCopyTrackedDerivedDerivedClass(int x) {
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return new CopyTrackedDerivedDerivedClass(x);
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}
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class SubscriptReturnsRef {
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public:
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const int &operator [](int y) const {
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return x[y];
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}
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int &operator [](int y) {
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return x[y];
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}
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private:
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int x[10] = {0};
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};
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class DerivedSubscriptReturnsRef: public SubscriptReturnsRef {
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public:
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inline DerivedSubscriptReturnsRef() : SubscriptReturnsRef() {}
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};
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class NonConstSubscriptReturnsRef {
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public:
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int &operator [](int y) {
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return x[y];
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}
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private:
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int x[10] = {0};
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};
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class DerivedNonConstSubscriptReturnsRef: public NonConstSubscriptReturnsRef {
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public:
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inline DerivedNonConstSubscriptReturnsRef() : NonConstSubscriptReturnsRef() {}
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};

‎test/Interop/Cxx/class/inheritance/fields-irgen.swift‎

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
// RUN: %target-swift-emit-irgen -I %S/Inputs -enable-experimental-cxx-interop %s -validate-tbd-against-ir=none -Xcc -fignore-exceptions | %FileCheck %s
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import Fields
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func testGetX() -> CInt {
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let derivedDerived = CopyTrackedDerivedDerivedClass(42)
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return derivedDerived.x
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}
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let _ = testGetX()
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// CHECK: define {{.*}}linkonce_odr{{.*}} i32 @{{.*}}__synthesizedBaseCall___synthesizedBaseGetterAccessor{{.*}}(ptr {{.*}} %[[THIS_PTR:.*]])
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// CHECK: %[[ADD_PTR:.*]] = getelementptr inbounds i8, ptr %{{.*}}, i64 4
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// CHECK: call noundef i32 @{{.*}}__synthesizedBaseGetterAccessor{{.*}}(ptr {{.*}} %[[ADD_PTR]])

‎test/Interop/Cxx/class/inheritance/fields-silgen.swift‎

Lines changed: 15 additions & 0 deletions
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@@ -0,0 +1,15 @@
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// RUN: %target-swift-emit-sil -I %S/Inputs -enable-experimental-cxx-interop %s -validate-tbd-against-ir=none | %FileCheck %s
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import Fields
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func testGetX() -> CInt {
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let derived = CopyTrackedDerivedClass(42)
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return derived.x
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}
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let _ = testGetX()
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// CHECK: sil shared [transparent] @$sSo23CopyTrackedDerivedClassV1xs5Int32Vvg : $@convention(method) (@in_guaranteed CopyTrackedDerivedClass) -> Int32
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// CHECK: {{.*}}(%[[SELF_VAL:.*]] : $*CopyTrackedDerivedClass):
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// CHECK: function_ref @{{.*}}__synthesizedBaseGetterAccessor_{{.*}} : $@convention(cxx_method) (@in_guaranteed CopyTrackedDerivedClass) -> Int32
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// CHECK-NEXT: apply %{{.*}}(%[[SELF_VAL]])

‎test/Interop/Cxx/class/inheritance/fields.swift‎

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -85,4 +85,31 @@ FieldsTestSuite.test("Same field from derived") {
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expectEqual(derived.a, 42)
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}
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extension CopyTrackedBaseClass {
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var swiftProp: CInt {
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return x
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}
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}
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FieldsTestSuite.test("Get field without copying base in the getter accessor") {
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let base = CopyTrackedBaseClass(0)
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var copyCounter = getCopyCounter().pointee
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expectEqual(base.swiftProp, 0)
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// Measure copy counter of a regular
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// property access for a C++ type to compare
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// it to see if any additional copies are
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// needed to access the property from the base class.
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let expectedCopyCountDiff = getCopyCounter().pointee - copyCounter
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let derived = CopyTrackedDerivedClass(234)
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copyCounter = getCopyCounter().pointee
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expectEqual(derived.x, 234)
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expectEqual(copyCounter, getCopyCounter().pointee - expectedCopyCountDiff)
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let derivedDerived = CopyTrackedDerivedDerivedClass(-11)
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copyCounter = getCopyCounter().pointee
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expectEqual(derivedDerived.x, -11)
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expectEqual(copyCounter, getCopyCounter().pointee - expectedCopyCountDiff)
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}
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runAllTests()

‎test/Interop/Cxx/class/inheritance/subscript-irgen.swift‎

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
// RUN: %target-swift-emit-irgen -I %S/Inputs -enable-experimental-cxx-interop %s -validate-tbd-against-ir=none -Xcc -fignore-exceptions | %FileCheck %s
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import Subscripts
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func testGetX() -> CInt {
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let derivedDerived = CopyTrackedDerivedDerivedClass(42)
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return derivedDerived[0]
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}
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let _ = testGetX()
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// CHECK: define {{.*}}linkonce_odr{{.*}} i32 @{{.*}}__synthesizedBaseCall___synthesizedBaseCall_operatorSubscript{{.*}}(ptr {{.*}} %[[THIS_PTR:.*]], i32 {{.*}})
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// CHECK: %[[ADD_PTR:.*]] = getelementptr inbounds i8, ptr %{{.*}}, i64 4
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// CHECK: call noundef i32 @{{.*}}__synthesizedBaseCall_operatorSubscript{{.*}}(ptr {{.*}} %[[ADD_PTR]], i32 {{.*}})

‎test/Interop/Cxx/class/inheritance/subscript-silgen.swift‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
// RUN: %target-swift-emit-sil -I %S/Inputs -enable-experimental-cxx-interop %s -validate-tbd-against-ir=none | %FileCheck %s
2+
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import Subscripts
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func testGetX() -> CInt {
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let derived = CopyTrackedDerivedClass(42)
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return derived[0]
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}
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let _ = testGetX()
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// CHECK: sil shared [transparent] @$sSo23CopyTrackedDerivedClassVys5Int32VADcig : $@convention(method) (Int32, @in_guaranteed CopyTrackedDerivedClass) -> Int32
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// CHECK: {{.*}}(%[[INT_VAL:.*]] : $Int32, %[[SELF_VAL:.*]] : $*CopyTrackedDerivedClass):
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// CHECK: function_ref @{{.*}}__synthesizedBaseCall_operatorSubscript{{.*}} : $@convention(cxx_method) (Int32, @in_guaranteed CopyTrackedDerivedClass) -> Int32
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// CHECK-NEXT: apply %{{.*}}(%[[INT_VAL]], %[[SELF_VAL]])

‎test/Interop/Cxx/class/inheritance/subscripts.swift‎

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,25 @@
1+
// RUN: %target-run-simple-swift(-I %S/Inputs/ -Xfrontend -enable-experimental-cxx-interop)
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//
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// REQUIRES: executable_test
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5+
import CxxShim
6+
import StdlibUnittest
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import Subscripts
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9+
var FieldsTestSuite = TestSuite("Getting and setting subscripts in base classes")
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11+
FieldsTestSuite.test("Subscript from derived returning ref") {
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var derived = DerivedSubscriptReturnsRef()
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expectEqual(derived[0], 0)
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derived[0] = 42
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expectEqual(derived[0], 42)
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}
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FieldsTestSuite.test("Non-const subscript from derived returning ref") {
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var derived = DerivedNonConstSubscriptReturnsRef()
20+
expectEqual(derived[1], 0)
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derived[1] = -11
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expectEqual(derived[1], -11)
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}
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runAllTests()

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