[interop][SwiftToCxx] the not yet implemented move constructor for Swift value types should lead to link error when a move is used in Swift, not runtime error

Author: hyp

lib/PrintAsClang/PrintClangValueType.cpp

@@ -308,11 +308,21 @@ void ClangValueTypePrinter::printValueTypeDecl(
 
   // FIXME: implement the move constructor.
   os << "  [[noreturn]] ";
-  printer.printInlineForThunk();
+  // NOTE: Do not apply attribute((used))
+  // here to ensure the linker error isn't
+  // forced, so just mark this an inline
+  // helper function instead.
+  printer.printInlineForHelperFunction();
   printer.printBaseName(typeDecl);
   os << "(";
   printer.printBaseName(typeDecl);
-  os << " &&) noexcept { abort(); }\n";
+  StringRef moveErrorMessage = "C++ does not support moving a Swift value yet";
+  os << " &&) noexcept {\n  "
+        "swift::_impl::_fatalError_Cxx_move_of_Swift_value_type_not_supported_"
+        "yet();\n  swift::_impl::_swift_stdlib_reportFatalError(\"swift\", 5, "
+        "\""
+     << moveErrorMessage << "\", " << moveErrorMessage.size()
+     << ", 0);\n  abort();\n  }\n";
 
   bodyPrinter();
   if (typeDecl->isStdlibDecl())

lib/PrintAsClang/_SwiftCxxInteroperability.h

@@ -93,6 +93,21 @@ extern "C" void *_Nonnull swift_retain(void *_Nonnull) noexcept;
 
 extern "C" void swift_release(void *_Nonnull) noexcept;
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreserved-identifier"
+
+extern "C" void _swift_stdlib_reportFatalError(const char *_Nonnull prefix,
+                                               int prefixLength,
+                                               const char *_Nonnull message,
+                                               int messageLength,
+                                               uint32_t flags) noexcept;
+
+// A dummy symbol that forces a linker error when
+// C++ tries to invoke a move of a Swift value type.
+extern "C" void _fatalError_Cxx_move_of_Swift_value_type_not_supported_yet();
+
+#pragma clang diagnostic pop
+
 SWIFT_INLINE_THUNK void *_Nonnull opaqueAlloc(size_t size,
                                               size_t align) noexcept {
 #if defined(_WIN32)

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

@@ -83,6 +83,7 @@ public final class ExposedClass {
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct final {
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct2 final {
 // CHECK: ExposedStruct2(ExposedStruct2 &&)
+// CHECK: }
 // CHECK-NEXT: swift::Int getY() const SWIFT_SYMBOL("{{.*}}");
 // CHECK-NEXT: void setY(swift::Int value) SWIFT_SYMBOL("{{.*}}");
 // CHECK-NEXT: static SWIFT_INLINE_THUNK ExposedStruct2 init() SWIFT_SYMBOL("{{.*}}");

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

@@ -39,7 +39,8 @@ public struct FirstSmallStruct {
 
 // CHECK: class SWIFT_SYMBOL("s:4Init16FirstSmallStructV") FirstSmallStruct final {
 // CHECK-NEXT: public:
-// CHECK:   SWIFT_INLINE_THUNK FirstSmallStruct(FirstSmallStruct &&)
+// CHECK:   SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
+// CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL("s:4Init16FirstSmallStructV1xs6UInt32Vvp");
 // CHECK-NEXT:   static SWIFT_INLINE_THUNK FirstSmallStruct init() SWIFT_SYMBOL("s:4Init16FirstSmallStructVACycfc");
 // CHECK-NEXT:   static SWIFT_INLINE_THUNK FirstSmallStruct init(swift::Int x) SWIFT_SYMBOL("s:4Init16FirstSmallStructVyACSicfc");

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

@@ -95,7 +95,8 @@ public final class PassStructInClassMethod {
 // CHECK-NEXT:   static SWIFT_INLINE_THUNK LargeStruct staticFinalClassMethod(swift::Int x) SWIFT_SYMBOL("s:7Methods09ClassWithA0C011staticFinalB6Method1xAA11LargeStructVSi_tFZ");
 
 // CHECK: class SWIFT_SYMBOL("s:7Methods11LargeStructV") LargeStruct final {
-// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK LargeStruct doubled() const SWIFT_SYMBOL("s:7Methods11LargeStructV7doubledACyF");
 // CHECK-NEXT: SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11LargeStructV4dumpyyF");
 // 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

@@ -57,14 +57,16 @@ public struct SmallStruct {
 // CHECK: SWIFT_EXTERN void $s7Methods11SmallStructV6invertyyF(SWIFT_CONTEXT void * _Nonnull _self) SWIFT_NOEXCEPT SWIFT_CALL; // invert()
 
 // CHECK: class SWIFT_SYMBOL("s:7Methods11LargeStructV") LargeStruct final {
-// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11LargeStructV4dumpyyF");
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void double_() SWIFT_SYMBOL("s:7Methods11LargeStructV6doubleyyF");
 // CHECK-NEXT:   SWIFT_INLINE_THUNK LargeStruct scale(swift::Int x, swift::Int y) SWIFT_SYMBOL("s:7Methods11LargeStructV5scaleyACSi_SitF");
 // CHECK-NEXT: private
 
 // CHECK: class SWIFT_SYMBOL("s:7Methods11SmallStructV") SmallStruct final {
-// CHECK:   SWIFT_INLINE_THUNK SmallStruct(SmallStruct &&)
+// CHECK:   SWIFT_INLINE_PRIVATE_HELPER SmallStruct(SmallStruct &&)
+// CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void dump() const SWIFT_SYMBOL("s:7Methods11SmallStructV4dumpyyF");
 // CHECK-NEXT:   SWIFT_INLINE_THUNK SmallStruct scale(float y) SWIFT_SYMBOL("s:7Methods11SmallStructV5scaleyACSfF");
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void invert() SWIFT_SYMBOL("s:7Methods11SmallStructV6invertyyF");

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

@@ -10,7 +10,8 @@ public struct FirstSmallStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) FirstSmallStruct final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_THUNK FirstSmallStruct(FirstSmallStruct &&)
+// CHECK:   SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
+// CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:   private:
 
@@ -36,7 +37,8 @@ public struct LargeStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) LargeStruct final {
 // CHECK: public:
-// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX1() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX2() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX3() const SWIFT_SYMBOL({{.*}});
@@ -92,7 +94,8 @@ public struct SmallStructWithGetters {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) SmallStructWithGetters final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_THUNK SmallStructWithGetters(SmallStructWithGetters &&)
+// CHECK:   SWIFT_INLINE_PRIVATE_HELPER SmallStructWithGetters(SmallStructWithGetters &&)
+// CHECK: }
 // CHECK-NEXT:  SWIFT_INLINE_THUNK uint32_t getStoredInt() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:  SWIFT_INLINE_THUNK swift::Int getComputedInt() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:  SWIFT_INLINE_THUNK LargeStruct getLargeStruct() const SWIFT_SYMBOL({{.*}});

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

@@ -10,7 +10,8 @@ public struct FirstSmallStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) FirstSmallStruct final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_THUNK FirstSmallStruct(FirstSmallStruct &&)
+// CHECK:   SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
+// CHECK: }
 // CHECK-NEXT:   SWIFT_INLINE_THUNK uint32_t getX() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:   SWIFT_INLINE_THUNK void setX(uint32_t value) SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:   private:
@@ -31,7 +32,8 @@ public struct LargeStruct {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) LargeStruct final {
 // CHECK: public:
-// CHECK: SWIFT_INLINE_THUNK LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX1() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT: SWIFT_INLINE_THUNK void setX1(swift::Int value) SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT: SWIFT_INLINE_THUNK swift::Int getX2() const SWIFT_SYMBOL({{.*}});
@@ -109,7 +111,8 @@ public struct SmallStructWithProps {
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) SmallStructWithProps final {
 // CHECK: public:
-// CHECK:   SWIFT_INLINE_THUNK SmallStructWithProps(SmallStructWithProps &&)
+// CHECK:   SWIFT_INLINE_PRIVATE_HELPER SmallStructWithProps(SmallStructWithProps &&)
+// CHECK: }
 // CHECK-NEXT:    SWIFT_INLINE_THUNK uint32_t getStoredInt() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:    SWIFT_INLINE_THUNK void setStoredInt(uint32_t value) SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:    SWIFT_INLINE_THUNK swift::Int getComputedInt() const SWIFT_SYMBOL({{.*}});

test/Interop/SwiftToCxx/stdlib/swift-stdlib-in-cxx.swift

@@ -72,7 +72,8 @@
 // CHECK:  }
 // CHECK-NEXT:  SWIFT_INLINE_THUNK String(const String &other) noexcept {
 // CHECK:  }
-// CHECK-NEXT:  SWIFT_INLINE_THUNK String(String &&) noexcept { abort(); }
+// CHECK-NEXT:  SWIFT_INLINE_PRIVATE_HELPER String(String &&) noexcept {
+// CHECK: }
 // CHECK-NEXT:  static SWIFT_INLINE_THUNK String init() SWIFT_SYMBOL({{.*}});
 // CHECK:  SWIFT_INLINE_THUNK void append(const String& other)
 // CHECK:  SWIFT_INLINE_THUNK UTF8View getUtf8() const SWIFT_SYMBOL({{.*}});
@@ -107,7 +108,8 @@
 // CHECK-NEXT: private:
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) UTF8View final {
-// CHECK:  SWIFT_INLINE_THUNK UTF8View(UTF8View &&) noexcept { abort(); }
+// CHECK: SWIFT_INLINE_PRIVATE_HELPER UTF8View(UTF8View &&) noexcept {
+// CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK String_Index getStartIndex() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:   SWIFT_INLINE_THUNK String_Index getEndIndex() const SWIFT_SYMBOL({{.*}});
 // CHECK:   SWIFT_INLINE_THUNK swift::Optional<String_Index> indexOffsetByLimitedBy(const String_Index& i, swift::Int n, const String_Index& limit) const SWIFT_SYMBOL({{.*}});

test/Interop/SwiftToCxx/structs/struct-move-semantics-in-cxx.cpp

@@ -0,0 +1,41 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-frontend %S/large-structs-pass-return-indirect-in-cxx.swift -typecheck -module-name Structs -clang-header-expose-decls=all-public -emit-clang-header-path %t/structs.h
+
+// Link should fail by default when a move is
+// performed in C++.
+// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o
+// RUN: not %target-interop-build-swift %S/large-structs-pass-return-indirect-in-cxx.swift -o %t/swift-structs-execution -Xlinker %t/swift-structs-execution.o -module-name Structs -Xfrontend -entry-point-function-name -Xfrontend swiftMain 2>&1 | %FileCheck --check-prefix=LINK %s
+
+// LINK: fatalError_Cxx_move_of_Swift_value_type_not_supported_yet
+
+// Fallback to abort at runtime:
+
+// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o -DLINKS
+// RUN: %target-interop-build-swift %S/large-structs-pass-return-indirect-in-cxx.swift -o %t/swift-structs-execution -Xlinker %t/swift-structs-execution.o -module-name Structs -Xfrontend -entry-point-function-name -Xfrontend swiftMain 2>&1
+
+// RUN: %target-codesign %t/swift-structs-execution
+// RUN: %target-run %t/swift-structs-execution 2>%t/output || true
+// RUN: cat %t/output  | %FileCheck %s
+
+// REQUIRES: executable_test
+
+#include <assert.h>
+#include "structs.h"
+#include <memory>
+
+#ifdef LINKS
+extern "C" void _fatalError_Cxx_move_of_Swift_value_type_not_supported_yet() {
+    
+}
+#endif
+
+int main() {
+  using namespace Structs;
+
+  auto x = returnNewStructSeveralI64(42);
+  StructSeveralI64 x2 = std::move(x);
+  return 0;
+}
+
+// CHECK: C++ does not support moving a Swift value yet