[cxx-interop] Do not generate aborting move constructors

In the reverse interop header we generated move constructors that call
abort at runtime. This is problematic for several reasons:
* In C++14 and below some of our own generated functions like _make
  ended up calling the move constructor. Those are calling abort and
  also trigger unreachable code warning in newer versions of Clang.
  In C++17 and up it is fine due to the guaranteed copy elision.
* Type traits are fooled and think these types are movable. As a result,
  libraries could generate calls to the aborting move ctor.

This PR removes the generation of move operations. As we generate copy
operations, the compiler will not declare or define the move operations
implicitly. Whenever the user goes out of their way and try to move an
object they will get a copy instead.

rdar://150793518

Author: Gabor Horvath

lib/PrintAsClang/PrintClangValueType.cpp

@@ -330,33 +330,7 @@ void ClangValueTypePrinter::printValueTypeDecl(
     os << "  }\n";
 
     // FIXME: implement the move assignment.
-    os << "  ";
-    printer.printInlineForThunk();
-    printer.printBaseName(typeDecl);
-    os << " &operator =(";
-    printer.printBaseName(typeDecl);
-    os << " &&other) = delete;\n";
-
     // FIXME: implement the move constructor.
-    os << "  [[noreturn]] ";
-    // 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);
-    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())

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

@@ -82,7 +82,7 @@ public final class ExposedClass {
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedClass final
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct final {
 // CHECK: class SWIFT_SYMBOL("{{.*}}") ExposedStruct2 final {
-// CHECK: ExposedStruct2(ExposedStruct2 &&)
+// CHECK: SWIFT_INLINE_THUNK ExposedStruct2 &operator =(const ExposedStruct2 &other) noexcept {
 // CHECK: }
 // CHECK-NEXT: swift::Int getY() const SWIFT_SYMBOL("{{.*}}");
 // CHECK-NEXT: void setY(swift::Int value) SWIFT_SYMBOL("{{.*}}");

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

@@ -39,7 +39,7 @@ public struct FirstSmallStruct {
 
 // CHECK: class SWIFT_SYMBOL("s:4Init16FirstSmallStructV") FirstSmallStruct final {
 // CHECK-NEXT: public:
-// CHECK:   SWIFT_INLINE_PRIVATE_HELPER FirstSmallStruct(FirstSmallStruct &&)
+// CHECK: SWIFT_INLINE_THUNK FirstSmallStruct &operator =(const FirstSmallStruct &other) noexcept {
 // 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");

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

@@ -105,7 +105,7 @@ 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_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_THUNK LargeStruct &operator =(const LargeStruct &other) noexcept {
 // 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");

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

@@ -57,15 +57,15 @@ 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_PRIVATE_HELPER LargeStruct(LargeStruct &&)
+// CHECK: SWIFT_INLINE_THUNK LargeStruct &operator =(const LargeStruct &other) noexcept {
 // 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_PRIVATE_HELPER SmallStruct(SmallStruct &&)
+// CHECK: SWIFT_INLINE_THUNK SmallStruct &operator =(const SmallStruct &other) noexcept {
 // 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");

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

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

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

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

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

@@ -81,9 +81,6 @@
 // CHECK:  }
 // CHECK-NEXT:  SWIFT_INLINE_THUNK String &operator =(const String &other) noexcept {
 // CHECK:  }
-// CHECK-NEXT:  SWIFT_INLINE_THUNK String &operator =(String &&other) = delete;
-// 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 __StringNested::UTF8View getUtf8() const SWIFT_SYMBOL({{.*}});
@@ -118,7 +115,7 @@
 // CHECK-NEXT: private:
 
 // CHECK: class SWIFT_SYMBOL({{.*}}) UTF8View final {
-// CHECK: SWIFT_INLINE_PRIVATE_HELPER UTF8View(UTF8View &&) noexcept {
+// CHECK: SWIFT_INLINE_THUNK UTF8View &operator =(const UTF8View &other) noexcept {
 // CHECK: }
 // CHECK-NEXT: SWIFT_INLINE_THUNK __StringNested::Index getStartIndex() const SWIFT_SYMBOL({{.*}});
 // CHECK-NEXT:   SWIFT_INLINE_THUNK __StringNested::Index getEndIndex() const SWIFT_SYMBOL({{.*}});

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

@@ -5,47 +5,35 @@
 // 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
+// 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
 
 // Compile should fail by default when move assignment is attempted in C++:
 
-// RUN: not %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o -DMOVE_ASSIGN 2>&1 | %FileCheck --check-prefix=MOVEASSIGN %s
+// RUN: %target-interop-build-clangxx -c %s -I %t -o %t/swift-structs-execution.o -DMOVE_ASSIGN 2>&1
 
 // 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-clangxx -c %s -I %t -o %t/swift-structs-execution.o
 // 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);
 #ifdef MOVE_ASSIGN
   auto y = returnNewStructSeveralI64(24);
   x = std::move(y);
-// MOVEASSIGN: deleted operator '='
 #else
   StructSeveralI64 x2 = std::move(x);
 #endif
   return 0;
 }
-
-// CHECK: C++ does not support moving a Swift value yet

test/Interop/SwiftToCxx/structs/struct-with-refcounted-member.swift

@@ -58,10 +58,4 @@ public func printBreak(_ x: Int) {
 // CHECK-NEXT:     vwTable->assignWithCopy(_getOpaquePointer(), const_cast<char *>(other._getOpaquePointer()), metadata._0);
 // CHECK-NEXT:   return *this;
 // CHECK-NEXT:   }
-// CHECK-NEXT:   SWIFT_INLINE_THUNK StructWithRefcountedMember &operator =(StructWithRefcountedMember &&other) = delete;
-// CHECK-NEXT:   SWIFT_INLINE_PRIVATE_HELPER StructWithRefcountedMember(StructWithRefcountedMember &&) noexcept {
-// CHECK-NEXT:  swift::_impl::_fatalError_Cxx_move_of_Swift_value_type_not_supported_yet();
-// CHECK-NEXT:  swift::_impl::_swift_stdlib_reportFatalError("swift", 5, "C++ does not support moving a Swift value yet", 45, 0);
-// CHECK-NEXT:  abort();
-// CHECK-NEXT: }
 // CHECK-NEXT: private: