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Merge pull request #65749 from hyp/eng/move-semantics-fixups
[interop][SwiftToCxx] move semantics for Swift classes; use of C++ move for unimplemented Swift value moves fails at link time now
2 parents 08c4646 + 39d86bc commit 1bcda2f

14 files changed

+156
-21
lines changed

‎lib/PrintAsClang/PrintClangValueType.cpp‎

Lines changed: 12 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -308,11 +308,21 @@ void ClangValueTypePrinter::printValueTypeDecl(
308308

309309
// FIXME: implement the move constructor.
310310
os << " [[noreturn]] ";
311-
printer.printInlineForThunk();
311+
// NOTE: Do not apply attribute((used))
312+
// here to ensure the linker error isn't
313+
// forced, so just mark this an inline
314+
// helper function instead.
315+
printer.printInlineForHelperFunction();
312316
printer.printBaseName(typeDecl);
313317
os << "(";
314318
printer.printBaseName(typeDecl);
315-
os << " &&) noexcept { abort(); }\n";
319+
StringRef moveErrorMessage = "C++ does not support moving a Swift value yet";
320+
os << " &&) noexcept {\n "
321+
"swift::_impl::_fatalError_Cxx_move_of_Swift_value_type_not_supported_"
322+
"yet();\n swift::_impl::_swift_stdlib_reportFatalError(\"swift\", 5, "
323+
"\""
324+
<< moveErrorMessage << "\", " << moveErrorMessage.size()
325+
<< ", 0);\n abort();\n }\n";
316326

317327
bodyPrinter();
318328
if (typeDecl->isStdlibDecl())

‎lib/PrintAsClang/_SwiftCxxInteroperability.h‎

Lines changed: 30 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -93,6 +93,21 @@ extern "C" void *_Nonnull swift_retain(void *_Nonnull) noexcept;
9393

9494
extern "C" void swift_release(void *_Nonnull) noexcept;
9595

96+
#pragma clang diagnostic push
97+
#pragma clang diagnostic ignored "-Wreserved-identifier"
98+
99+
extern "C" void _swift_stdlib_reportFatalError(const char *_Nonnull prefix,
100+
int prefixLength,
101+
const char *_Nonnull message,
102+
int messageLength,
103+
uint32_t flags) noexcept;
104+
105+
// A dummy symbol that forces a linker error when
106+
// C++ tries to invoke a move of a Swift value type.
107+
extern "C" void _fatalError_Cxx_move_of_Swift_value_type_not_supported_yet();
108+
109+
#pragma clang diagnostic pop
110+
96111
SWIFT_INLINE_THUNK void *_Nonnull opaqueAlloc(size_t size,
97112
size_t align) noexcept {
98113
#if defined(_WIN32)
@@ -159,18 +174,28 @@ class RefCountedClass {
159174
: _opaquePointer(other._opaquePointer) {
160175
swift_retain(_opaquePointer);
161176
}
177+
SWIFT_INLINE_THUNK RefCountedClass(RefCountedClass &&other) noexcept
178+
: _opaquePointer(other._opaquePointer) {
179+
// Moving a Swift class reference is a copy
180+
// in C++. This allows C++ to avoid liveness
181+
// checks to see if the pointer is `null` or not,
182+
// as C++'s move is not consuming, unlike Swift's.
183+
swift_retain(_opaquePointer);
184+
}
162185
SWIFT_INLINE_THUNK RefCountedClass &
163186
operator=(const RefCountedClass &other) noexcept {
164187
swift_retain(other._opaquePointer);
165188
swift_release(_opaquePointer);
166189
_opaquePointer = other._opaquePointer;
167190
return *this;
168191
}
169-
#pragma clang diagnostic push
170-
#pragma clang diagnostic ignored "-Wmissing-noreturn"
171-
// FIXME: implement 'move'?
172-
SWIFT_INLINE_THUNK RefCountedClass(RefCountedClass &&) noexcept { abort(); }
173-
#pragma clang diagnostic pop
192+
SWIFT_INLINE_THUNK RefCountedClass &
193+
operator=(RefCountedClass &&other) noexcept {
194+
swift_retain(other._opaquePointer);
195+
swift_release(_opaquePointer);
196+
_opaquePointer = other._opaquePointer;
197+
return *this;
198+
}
174199

175200
protected:
176201
SWIFT_INLINE_THUNK RefCountedClass(void *_Nonnull ptr) noexcept

‎test/Interop/SwiftToCxx/class/swift-class-execution.cpp‎

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -132,6 +132,33 @@ int main() {
132132
// CHECK-NEXT: init ClassWithIntField
133133
// CHECK-NEXT: destroy ClassWithIntField
134134
// CHECK-NEXT: ClassWithIntField: 0;
135+
// CHECK-NEXT: destroy ClassWithIntField
136+
137+
{
138+
auto x = returnClassWithIntField();
139+
assert(getRetainCount(x) == 1);
140+
ClassWithIntField x2(std::move(x));
141+
// Moving a Swift class in C++ is not consuming.
142+
assert(getRetainCount(x) == 2);
143+
}
144+
// CHECK-NEXT: init ClassWithIntField
145+
// CHECK-NEXT: destroy ClassWithIntField
146+
147+
{
148+
auto x = returnClassWithIntField();
149+
auto x2 = returnClassWithIntField();
150+
assert(getRetainCount(x) == 1);
151+
assert(getRetainCount(x2) == 1);
152+
x2 = std::move(x);
153+
// Moving a Swift class in C++ is not consuming.
154+
assert(getRetainCount(x) == 2);
155+
assert(getRetainCount(x2) == 2);
156+
takeClassWithIntField(x2);
157+
}
158+
// CHECK-NEXT: init ClassWithIntField
159+
// CHECK-NEXT: init ClassWithIntField
160+
// CHECK-NEXT: destroy ClassWithIntField
161+
// CHECK-NEXT: ClassWithIntField: 0;
135162
// CHECK-NEXT: destroy ClassWithIntField
136163
return 0;
137164
}

‎test/Interop/SwiftToCxx/class/swift-class-inheritance-execution.cpp‎

Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -95,6 +95,17 @@ int main() {
9595
// CHECK-NEXT: useDerivedClass, type=Class.DerivedDerivedClass
9696
// CHECK-NEXT: destroy DerivedDerivedClass
9797
// CHECK-NEXT: destroy DerivedClass
98+
// CHECK-NEXT: destroy BaseClass
99+
100+
{
101+
BaseClass x = returnDerivedClass();
102+
assert(getRetainCount(x) == 1);
103+
useBaseClass(x);
104+
}
105+
// CHECK-NEXT: init BaseClass
106+
// CHECK-NEXT: init DerivedClass
107+
// CHECK-NEXT: useBaseClass, type=Class.DerivedClass
108+
// CHECK-NEXT: destroy DerivedClass
98109
// CHECK-NEXT: destroy BaseClass
99110
return 0;
100111
}

‎test/Interop/SwiftToCxx/expose-attr/expose-swift-decls-to-cxx.swift‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -83,6 +83,7 @@ public final class ExposedClass {
8383
// CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct final {
8484
// CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct2 final {
8585
// CHECK: ExposedStruct2(ExposedStruct2 &&)
86+
// CHECK: }
8687
// CHECK-NEXT: swift::Int getY() const SWIFT_SYMBOL("{{.*}}");
8788
// CHECK-NEXT: void setY(swift::Int value) SWIFT_SYMBOL("{{.*}}");
8889
// CHECK-NEXT: static SWIFT_INLINE_THUNK ExposedStruct2 init() SWIFT_SYMBOL("{{.*}}");

‎test/Interop/SwiftToCxx/initializers/init-in-cxx.swift‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -39,7 +39,8 @@ public struct FirstSmallStruct {
3939

4040
// CHECK: class SWIFT_SYMBOL("s:4Init16FirstSmallStructV") FirstSmallStruct final {
4141
// CHECK-NEXT: public:
42-
// CHECK: SWIFT_INLINE_THUNK FirstSmallStruct(FirstSmallStruct &&)
42+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
43+
// CHECK: }
4344
// CHECK-NEXT: SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL("s:4Init16FirstSmallStructV1xs6UInt32Vvp");
4445
// CHECK-NEXT: static SWIFT_INLINE_THUNK FirstSmallStruct init() SWIFT_SYMBOL("s:4Init16FirstSmallStructVACycfc");
4546
// CHECK-NEXT: static SWIFT_INLINE_THUNK FirstSmallStruct init(swift::Int x) SWIFT_SYMBOL("s:4Init16FirstSmallStructVyACSicfc");

‎test/Interop/SwiftToCxx/methods/method-in-cxx.swift‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -95,7 +95,8 @@ public final class PassStructInClassMethod {
9595
// CHECK-NEXT: static SWIFT_INLINE_THUNK LargeStruct staticFinalClassMethod(swift::Int x) SWIFT_SYMBOL("s:7Methods09ClassWithA0C011staticFinalB6Method1xAA11LargeStructVSi_tFZ");
9696

9797
// CHECK: class SWIFT_SYMBOL("s:7Methods11LargeStructV") LargeStruct final {
98-
// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
98+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
99+
// CHECK: }
99100
// CHECK-NEXT: SWIFT_INLINE_THUNK LargeStruct doubled() const SWIFT_SYMBOL("s:7Methods11LargeStructV7doubledACyF");
100101
// CHECK-NEXT: SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11LargeStructV4dumpyyF");
101102
// CHECK-NEXT: SWIFT_INLINE_THUNK LargeStruct scaled(swift::Int x, swift::Int y) const SWIFT_SYMBOL("s:7Methods11LargeStructV6scaledyACSi_SitF");

‎test/Interop/SwiftToCxx/methods/mutating-method-in-cxx.swift‎

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -57,14 +57,16 @@ public struct SmallStruct {
5757
// CHECK: SWIFT_EXTERN void $s7Methods11SmallStructV6invertyyF(SWIFT_CONTEXT void * _Nonnull _self) SWIFT_NOEXCEPT SWIFT_CALL; // invert()
5858

5959
// CHECK: class SWIFT_SYMBOL("s:7Methods11LargeStructV") LargeStruct final {
60-
// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
60+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
61+
// CHECK: }
6162
// CHECK-NEXT: SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11LargeStructV4dumpyyF");
6263
// CHECK-NEXT: SWIFT_INLINE_THUNK void double_() SWIFT_SYMBOL("s:7Methods11LargeStructV6doubleyyF");
6364
// CHECK-NEXT: SWIFT_INLINE_THUNK LargeStruct scale(swift::Int x, swift::Int y) SWIFT_SYMBOL("s:7Methods11LargeStructV5scaleyACSi_SitF");
6465
// CHECK-NEXT: private
6566

6667
// CHECK: class SWIFT_SYMBOL("s:7Methods11SmallStructV") SmallStruct final {
67-
// CHECK: SWIFT_INLINE_THUNK SmallStruct(SmallStruct &&)
68+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER SmallStruct(SmallStruct &&)
69+
// CHECK: }
6870
// CHECK-NEXT: SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11SmallStructV4dumpyyF");
6971
// CHECK-NEXT: SWIFT_INLINE_THUNK SmallStruct scale(float y) SWIFT_SYMBOL("s:7Methods11SmallStructV5scaleyACSfF");
7072
// CHECK-NEXT: SWIFT_INLINE_THUNK void invert() SWIFT_SYMBOL("s:7Methods11SmallStructV6invertyyF");

‎test/Interop/SwiftToCxx/properties/getter-in-cxx.swift‎

Lines changed: 6 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,8 @@ public struct FirstSmallStruct {
1010

1111
// CHECK: class SWIFT_SYMBOL({{.*}}) FirstSmallStruct final {
1212
// CHECK: public:
13-
// CHECK: SWIFT_INLINE_THUNK FirstSmallStruct(FirstSmallStruct &&)
13+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
14+
// CHECK: }
1415
// CHECK-NEXT: SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL({{.*}});
1516
// CHECK-NEXT: private:
1617

@@ -36,7 +37,8 @@ public struct LargeStruct {
3637

3738
// CHECK: class SWIFT_SYMBOL({{.*}}) LargeStruct final {
3839
// CHECK: public:
39-
// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
40+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
41+
// CHECK: }
4042
// CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX1() const SWIFT_SYMBOL({{.*}});
4143
// CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX2() const SWIFT_SYMBOL({{.*}});
4244
// CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX3() const SWIFT_SYMBOL({{.*}});
@@ -92,7 +94,8 @@ public struct SmallStructWithGetters {
9294

9395
// CHECK: class SWIFT_SYMBOL({{.*}}) SmallStructWithGetters final {
9496
// CHECK: public:
95-
// CHECK: SWIFT_INLINE_THUNK SmallStructWithGetters(SmallStructWithGetters &&)
97+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER SmallStructWithGetters(SmallStructWithGetters &&)
98+
// CHECK: }
9699
// CHECK-NEXT: SWIFT_INLINE_THUNK uint32_t getStoredInt() const SWIFT_SYMBOL({{.*}});
97100
// CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getComputedInt() const SWIFT_SYMBOL({{.*}});
98101
// CHECK-NEXT: SWIFT_INLINE_THUNK LargeStruct getLargeStruct() const SWIFT_SYMBOL({{.*}});

‎test/Interop/SwiftToCxx/properties/setter-in-cxx.swift‎

Lines changed: 6 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,8 @@ public struct FirstSmallStruct {
1010

1111
// CHECK: class SWIFT_SYMBOL({{.*}}) FirstSmallStruct final {
1212
// CHECK: public:
13-
// CHECK: SWIFT_INLINE_THUNK FirstSmallStruct(FirstSmallStruct &&)
13+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
14+
// CHECK: }
1415
// CHECK-NEXT: SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL({{.*}});
1516
// CHECK-NEXT: SWIFT_INLINE_THUNK void setX(uint32_t value) SWIFT_SYMBOL({{.*}});
1617
// CHECK-NEXT: private:
@@ -31,7 +32,8 @@ public struct LargeStruct {
3132

3233
// CHECK: class SWIFT_SYMBOL({{.*}}) LargeStruct final {
3334
// CHECK: public:
34-
// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
35+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
36+
// CHECK: }
3537
// CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX1() const SWIFT_SYMBOL({{.*}});
3638
// CHECK-NEXT: SWIFT_INLINE_THUNK void setX1(swift::Int value) SWIFT_SYMBOL({{.*}});
3739
// CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX2() const SWIFT_SYMBOL({{.*}});
@@ -109,7 +111,8 @@ public struct SmallStructWithProps {
109111

110112
// CHECK: class SWIFT_SYMBOL({{.*}}) SmallStructWithProps final {
111113
// CHECK: public:
112-
// CHECK: SWIFT_INLINE_THUNK SmallStructWithProps(SmallStructWithProps &&)
114+
// CHECK: SWIFT_INLINE_PRIVATE_HELPER SmallStructWithProps(SmallStructWithProps &&)
115+
// CHECK: }
113116
// CHECK-NEXT: SWIFT_INLINE_THUNK uint32_t getStoredInt() const SWIFT_SYMBOL({{.*}});
114117
// CHECK-NEXT: SWIFT_INLINE_THUNK void setStoredInt(uint32_t value) SWIFT_SYMBOL({{.*}});
115118
// CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getComputedInt() const SWIFT_SYMBOL({{.*}});

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