[cxx-interop] enable support for move-only types

lib/ClangImporter/ImportDecl.cpp

@@ -125,12 +125,22 @@ void ClangImporter::Implementation::makeComputed(AbstractStorageDecl *storage,
                                                  AccessorDecl *getter,
                                                  AccessorDecl *setter) {
   assert(getter);
+  // The synthesized computed property can either use a `get` or an
+  // `unsafeAddress` accessor.
+  auto isAddress = getter->getAccessorKind() == AccessorKind::Address;
   storage->getASTContext().evaluator.cacheOutput(HasStorageRequest{storage}, false);
   if (setter) {
-    storage->setImplInfo(StorageImplInfo::getMutableComputed());
+    if (isAddress)
+      assert(setter->getAccessorKind() == AccessorKind::MutableAddress);
+    storage->setImplInfo(
+        isAddress ? StorageImplInfo(ReadImplKind::Address,
+                                    WriteImplKind::MutableAddress,
+                                    ReadWriteImplKind::MutableAddress)
+                  : StorageImplInfo::getMutableComputed());
     storage->setAccessors(SourceLoc(), {getter, setter}, SourceLoc());
   } else {
-    storage->setImplInfo(StorageImplInfo::getImmutableComputed());
+    storage->setImplInfo(isAddress ? StorageImplInfo(ReadImplKind::Address)
+                                   : StorageImplInfo::getImmutableComputed());
     storage->setAccessors(SourceLoc(), {getter}, SourceLoc());
   }
 }
@@ -2183,17 +2193,23 @@ namespace {
       Impl.ImportedDecls[{decl->getCanonicalDecl(), getVersion()}] = result;
 
       if (recordHasMoveOnlySemantics(decl)) {
-        if (!Impl.SwiftContext.LangOpts.hasFeature(Feature::MoveOnly)) {
+        if (Impl.isCxxInteropCompatVersionAtLeast(
+                version::getUpcomingCxxInteropCompatVersion())) {
+          if (decl->isInStdNamespace() && decl->getName() == "promise") {
+            // Do not import std::promise.
+            return nullptr;
+          }
+          result->getAttrs().add(new (Impl.SwiftContext)
+                                     MoveOnlyAttr(/*Implicit=*/true));
+        } else {
           Impl.addImportDiagnostic(
-              decl, Diagnostic(
-                        diag::move_only_requires_move_only,
-                        Impl.SwiftContext.AllocateCopy(decl->getNameAsString())),
+              decl,
+              Diagnostic(
+                  diag::move_only_requires_move_only,
+                  Impl.SwiftContext.AllocateCopy(decl->getNameAsString())),
               decl->getLocation());
           return nullptr;
         }
-
-        result->getAttrs().add(new (Impl.SwiftContext)
-                                   MoveOnlyAttr(/*Implicit=*/true));
       }
 
       // FIXME: Figure out what to do with superclasses in C++. One possible
@@ -3931,7 +3947,7 @@ namespace {
       auto loc = Impl.importSourceLoc(decl->getLocation());
       auto dc = Impl.importDeclContextOf(
           decl, importedName.getEffectiveContext());
-
+      
       SmallVector<GenericTypeParamDecl *, 4> genericParams;
       for (auto &param : *decl->getTemplateParameters()) {
         auto genericParamDecl =

lib/ClangImporter/SwiftDeclSynthesizer.cpp

@@ -1496,12 +1496,36 @@ AccessorDecl *SwiftDeclSynthesizer::buildSubscriptSetterDecl(
 
 // MARK: C++ subscripts
 
+Expr *SwiftDeclSynthesizer::synthesizeReturnReinterpretCast(ASTContext &ctx,
+                                                            Type givenType,
+                                                            Type exprType,
+                                                            Expr *baseExpr) {
+  auto reinterpretCast = cast<FuncDecl>(
+      getBuiltinValueDecl(ctx, ctx.getIdentifier("reinterpretCast")));
+  SubstitutionMap subMap = SubstitutionMap::get(
+      reinterpretCast->getGenericSignature(), {givenType, exprType}, {});
+  ConcreteDeclRef concreteDeclRef(reinterpretCast, subMap);
+  auto reinterpretCastRef =
+      new (ctx) DeclRefExpr(concreteDeclRef, DeclNameLoc(), /*implicit*/ true);
+  FunctionType::ExtInfo info;
+  reinterpretCastRef->setType(
+      FunctionType::get({FunctionType::Param(givenType)}, exprType, info));
+
+  auto *argList = ArgumentList::forImplicitUnlabeled(ctx, {baseExpr});
+  auto reinterpreted =
+      CallExpr::createImplicit(ctx, reinterpretCastRef, argList);
+  reinterpreted->setType(exprType);
+  reinterpreted->setThrows(nullptr);
+  return reinterpreted;
+}
+
 /// Synthesizer callback for a subscript getter or a getter for a
 /// dereference property (`var pointee`). If the getter's implementation returns
 /// an UnsafePointer or UnsafeMutablePointer, it unwraps the pointer and returns
 /// the underlying value.
 static std::pair<BraceStmt *, bool>
-synthesizeUnwrappingGetterBody(AbstractFunctionDecl *afd, void *context) {
+synthesizeUnwrappingGetterOrAddressGetterBody(AbstractFunctionDecl *afd,
+                                              void *context, bool isAddress) {
   auto getterDecl = cast<AccessorDecl>(afd);
   auto getterImpl = static_cast<FuncDecl *>(context);
 
@@ -1525,7 +1549,8 @@ synthesizeUnwrappingGetterBody(AbstractFunctionDecl *afd, void *context) {
   // reference type. This check actually checks to see if the type is a pointer
   // type, but this does not apply to C pointers because they are Optional types
   // when imported. TODO: Use a more obvious check here.
-  if (getterImpl->getResultInterfaceType()->getAnyPointerElementType(ptrKind)) {
+  if (!isAddress &&
+      getterImpl->getResultInterfaceType()->getAnyPointerElementType(ptrKind)) {
     // `getterImpl` can return either UnsafePointer or UnsafeMutablePointer.
     // Retrieve the corresponding `.pointee` declaration.
     VarDecl *pointeePropertyDecl = ctx.getPointerPointeePropertyDecl(ptrKind);
@@ -1540,6 +1565,11 @@ synthesizeUnwrappingGetterBody(AbstractFunctionDecl *afd, void *context) {
     pointeePropertyRefExpr->setType(elementTy);
     propertyExpr = pointeePropertyRefExpr;
   }
+  // Cast an 'address' result from a mutable pointer if needed.
+  if (isAddress &&
+      getterImpl->getResultInterfaceType()->isUnsafeMutablePointer())
+    propertyExpr = SwiftDeclSynthesizer::synthesizeReturnReinterpretCast(
+        ctx, getterImpl->getResultInterfaceType(), elementTy, propertyExpr);
 
   auto returnStmt = new (ctx) ReturnStmt(SourceLoc(), propertyExpr,
                                          /*implicit*/ true);
@@ -1549,6 +1579,19 @@ synthesizeUnwrappingGetterBody(AbstractFunctionDecl *afd, void *context) {
   return {body, /*isTypeChecked*/ true};
 }
 
+static std::pair<BraceStmt *, bool>
+synthesizeUnwrappingGetterBody(AbstractFunctionDecl *afd, void *context) {
+  return synthesizeUnwrappingGetterOrAddressGetterBody(afd, context,
+                                                       /*isAddress=*/false);
+}
+
+static std::pair<BraceStmt *, bool>
+synthesizeUnwrappingAddressGetterBody(AbstractFunctionDecl *afd,
+                                      void *context) {
+  return synthesizeUnwrappingGetterOrAddressGetterBody(afd, context,
+                                                       /*isAddress=*/true);
+}
+
 /// Synthesizer callback for a subscript setter or a setter for a dereference
 /// property (`var pointee`).
 static std::pair<BraceStmt *, bool>
@@ -1596,6 +1639,26 @@ synthesizeUnwrappingSetterBody(AbstractFunctionDecl *afd, void *context) {
   return {body, /*isTypeChecked*/ true};
 }
 
+static std::pair<BraceStmt *, bool>
+synthesizeUnwrappingAddressSetterBody(AbstractFunctionDecl *afd,
+                                      void *context) {
+  auto setterDecl = cast<AccessorDecl>(afd);
+  auto setterImpl = static_cast<FuncDecl *>(context);
+
+  ASTContext &ctx = setterDecl->getASTContext();
+
+  auto selfArg = createSelfArg(setterDecl);
+  auto *setterImplCallExpr =
+      createAccessorImplCallExpr(setterImpl, selfArg, nullptr);
+
+  auto returnStmt = new (ctx) ReturnStmt(SourceLoc(), setterImplCallExpr,
+                                         /*implicit*/ true);
+
+  auto body = BraceStmt::create(ctx, SourceLoc(), {returnStmt}, SourceLoc(),
+                                /*implicit*/ true);
+  return {body, /*isTypeChecked*/ true};
+}
+
 SubscriptDecl *SwiftDeclSynthesizer::makeSubscript(FuncDecl *getter,
                                                    FuncDecl *setter) {
   assert((getter || setter) &&
@@ -1685,7 +1748,6 @@ SwiftDeclSynthesizer::makeDereferencedPointeeProperty(FuncDecl *getter,
                                                       FuncDecl *setter) {
   assert((getter || setter) &&
          "getter or setter required to generate a pointee property");
-
   auto &ctx = ImporterImpl.SwiftContext;
   FuncDecl *getterImpl = getter ? getter : setter;
   FuncDecl *setterImpl = setter;
@@ -1697,6 +1759,11 @@ SwiftDeclSynthesizer::makeDereferencedPointeeProperty(FuncDecl *getter,
   const auto elementTy = rawElementTy->getAnyPointerElementType()
                              ? rawElementTy->getAnyPointerElementType()
                              : rawElementTy;
+  // Use 'address' or 'mutableAddress' accessors for non-copyable
+  // types that are returned indirectly.
+  bool isImplicit = !elementTy->isNoncopyable(dc);
+  bool useAddress =
+      rawElementTy->getAnyPointerElementType() && elementTy->isNoncopyable(dc);
 
   auto result = new (ctx)
       VarDecl(/*isStatic*/ false, VarDecl::Introducer::Var,
@@ -1705,16 +1772,21 @@ SwiftDeclSynthesizer::makeDereferencedPointeeProperty(FuncDecl *getter,
   result->setAccess(AccessLevel::Public);
 
   AccessorDecl *getterDecl = AccessorDecl::create(
-      ctx, getterImpl->getLoc(), getterImpl->getLoc(), AccessorKind::Get,
-      result, SourceLoc(), StaticSpellingKind::None,
+      ctx, getterImpl->getLoc(), getterImpl->getLoc(),
+      useAddress ? AccessorKind::Address : AccessorKind::Get, result,
+      SourceLoc(), StaticSpellingKind::None,
       /*async*/ false, SourceLoc(),
       /*throws*/ false, SourceLoc(), /*ThrownType=*/TypeLoc(),
-      ParameterList::createEmpty(ctx), elementTy, dc);
+      ParameterList::createEmpty(ctx),
+      useAddress ? elementTy->wrapInPointer(PTK_UnsafePointer) : elementTy, dc);
   getterDecl->setAccess(AccessLevel::Public);
-  getterDecl->setImplicit();
+  if (isImplicit)
+    getterDecl->setImplicit();
   getterDecl->setIsDynamic(false);
   getterDecl->setIsTransparent(true);
-  getterDecl->setBodySynthesizer(synthesizeUnwrappingGetterBody,
+  getterDecl->setBodySynthesizer(useAddress
+                                     ? synthesizeUnwrappingAddressGetterBody
+                                     : synthesizeUnwrappingGetterBody,
                                  getterImpl);
 
   if (getterImpl->isMutating()) {
@@ -1733,20 +1805,29 @@ SwiftDeclSynthesizer::makeDereferencedPointeeProperty(FuncDecl *getter,
     paramVarDecl->setSpecifier(ParamSpecifier::Default);
     paramVarDecl->setInterfaceType(elementTy);
 
-    auto setterParamList =
-        ParameterList::create(ctx, {paramVarDecl});
+    auto setterParamList = useAddress
+                               ? ParameterList::create(ctx, {})
+                               : ParameterList::create(ctx, {paramVarDecl});
 
     setterDecl = AccessorDecl::create(
-        ctx, setterImpl->getLoc(), setterImpl->getLoc(), AccessorKind::Set,
-        result, SourceLoc(), StaticSpellingKind::None,
+        ctx, setterImpl->getLoc(), setterImpl->getLoc(),
+        useAddress ? AccessorKind::MutableAddress : AccessorKind::Set, result,
+        SourceLoc(), StaticSpellingKind::None,
         /*async*/ false, SourceLoc(),
         /*throws*/ false, SourceLoc(), /*ThrownType=*/TypeLoc(),
-        setterParamList, TupleType::getEmpty(ctx), dc);
+        setterParamList,
+        useAddress ? elementTy->wrapInPointer(PTK_UnsafeMutablePointer)
+                   : TupleType::getEmpty(ctx),
+        dc);
     setterDecl->setAccess(AccessLevel::Public);
-    setterDecl->setImplicit();
+    if (isImplicit)
+      setterDecl->setImplicit();
     setterDecl->setIsDynamic(false);
     setterDecl->setIsTransparent(true);
-    setterDecl->setBodySynthesizer(synthesizeUnwrappingSetterBody, setterImpl);
+    setterDecl->setBodySynthesizer(useAddress
+                                       ? synthesizeUnwrappingAddressSetterBody
+                                       : synthesizeUnwrappingSetterBody,
+                                   setterImpl);
 
     if (setterImpl->isMutating()) {
       setterDecl->setSelfAccessKind(SelfAccessKind::Mutating);

lib/ClangImporter/SwiftDeclSynthesizer.h

@@ -60,6 +60,10 @@ class SwiftDeclSynthesizer {
                        VarDecl::Introducer introducer, bool isImplicit,
                        AccessLevel access, AccessLevel setterAccess);
 
+  /// Create a reinterpretCast from the `exprType`, to the `givenType`.
+  static Expr *synthesizeReturnReinterpretCast(ASTContext &ctx, Type givenType,
+                                               Type exprType, Expr *baseExpr);
+
   /// Create a new named constant with the given value.
   ///
   /// \param name The name of the constant.

lib/ClangImporter/bridging

@@ -153,6 +153,11 @@
 #define SWIFT_UNCHECKED_SENDABLE \
   __attribute__((swift_attr("@Sendable")))
 
+/// Specifies that a specific c++ type such class or struct should be imported
+/// as a non-copyable Swift value type.
+#define SWIFT_NONCOPYABLE \
+  __attribute__((swift_attr("~Copyable")))
+
 #else  // #if _CXX_INTEROP_HAS_ATTRIBUTE(swift_attr)
 
 // Empty defines for compilers that don't support `attribute(swift_attr)`.
@@ -166,6 +171,7 @@
 #define SWIFT_COMPUTED_PROPERTY
 #define SWIFT_MUTATING 
 #define SWIFT_UNCHECKED_SENDABLE
+#define SWIFT_NONCOPYABLE
 
 #endif // #if _CXX_INTEROP_HAS_ATTRIBUTE(swift_attr)
 

test/Interop/Cxx/class/Inputs/type-classification.h

@@ -251,4 +251,15 @@ struct HasMethodThatReturnsIteratorBox {
   IteratorBox getIteratorBox() const;
 };
 
+struct __attribute__((swift_attr("~Copyable"))) StructCopyableMovableAnnotatedNonCopyable {
+  inline StructCopyableMovableAnnotatedNonCopyable() {}
+  StructCopyableMovableAnnotatedNonCopyable(const StructCopyableMovableAnnotatedNonCopyable &) = default;
+  StructCopyableMovableAnnotatedNonCopyable(StructCopyableMovableAnnotatedNonCopyable &&) = default;
+  StructCopyableMovableAnnotatedNonCopyable &
+  operator=(const StructCopyableMovableAnnotatedNonCopyable &) = default;
+    StructCopyableMovableAnnotatedNonCopyable &
+  operator=(StructCopyableMovableAnnotatedNonCopyable &&) = default;
+  ~StructCopyableMovableAnnotatedNonCopyable() = default;
+};
+
 #endif // TEST_INTEROP_CXX_CLASS_INPUTS_TYPE_CLASSIFICATION_H

test/Interop/Cxx/class/move-only/Inputs/module.modulemap

@@ -0,0 +1,4 @@
+module MoveOnlyCxxValueType {
+  header "move-only-cxx-value-type.h"
+  requires cplusplus
+}

test/Interop/Cxx/class/move-only/Inputs/move-only-cxx-value-type.h

@@ -0,0 +1,56 @@
+#ifndef TEST_INTEROP_CXX_CLASS_MOVE_ONLY_VT_H
+#define TEST_INTEROP_CXX_CLASS_MOVE_ONLY_VT_H
+
+#include <memory>
+
+struct Copyable {
+    int x;
+};
+
+struct NonCopyable {
+    inline NonCopyable(int x) : x(x) {}
+    inline NonCopyable(const NonCopyable &) = delete;
+    inline NonCopyable(NonCopyable &&other) : x(other.x) { other.x = -123; }
+
+    inline int method(int y) const { return x * y; }
+    inline int mutMethod(int y) {
+      x = y;
+      return y;
+    }
+
+    int x;
+};
+
+struct NonCopyableDerived: public NonCopyable {
+    NonCopyableDerived(int x) : NonCopyable(x) {}
+};
+
+struct NonCopyableDerivedDerived: public NonCopyableDerived {
+    NonCopyableDerivedDerived(int x) : NonCopyableDerived(x) {}
+};
+
+struct NonCopyableHolder {
+    inline NonCopyableHolder(int x) : x(x) {}
+    inline NonCopyableHolder(const NonCopyableHolder &) = delete;
+    inline NonCopyableHolder(NonCopyableHolder &&other) : x(std::move(other.x)) {}
+
+    inline NonCopyable &returnMutNonCopyableRef() { return x; }
+
+    inline const NonCopyable &returnNonCopyableRef() const { return x; }
+
+    NonCopyable x;
+};
+
+struct NonCopyableHolderDerived: NonCopyableHolder {
+    inline NonCopyableHolderDerived(int x) : NonCopyableHolder(x) {}
+};
+
+struct NonCopyableHolderDerivedDerived: NonCopyableHolderDerived {
+    inline NonCopyableHolderDerivedDerived(int x) : NonCopyableHolderDerived(x) {}
+
+    inline int getActualX() const {
+        return x.x;
+    }
+};
+
+#endif // TEST_INTEROP_CXX_CLASS_MOVE_ONLY_VT_H

test/Interop/Cxx/class/move-only/inherited-field-access-irgen.swift

@@ -0,0 +1,29 @@
+// RUN: %target-swift-emit-irgen -I %S/Inputs -cxx-interoperability-mode=upcoming-swift %s -validate-tbd-against-ir=none -Xcc -fignore-exceptions | %FileCheck %s
+
+import MoveOnlyCxxValueType
+
+func testGetX() -> CInt {
+    let derived = NonCopyableHolderDerivedDerived(42)
+    return derived.x.x
+}
+
+let _ = testGetX()
+
+func testSetX(_ x: CInt) {
+    var derived = NonCopyableHolderDerivedDerived(42)
+    derived.x.x = 2
+}
+
+testSetX(2)
+
+// CHECK: define {{.*}}linkonce_odr{{.*}} ptr @{{.*}}__synthesizedBaseCall___synthesizedBaseGetterAccessor{{.*}}
+
+// CHECK: define {{.*}}linkonce_odr{{.*}} ptr @{{.*}}__synthesizedBaseCall___synthesizedBaseSetterAccessor{{.*}}
+
+// CHECK: define {{.*}}linkonce_odr{{.*}} ptr @{{.*}}__synthesizedBaseGetterAccessor{{.*}}
+// CHECK: %[[VPTR:.*]] = getelementptr inbounds %struct.NonCopyableHolder
+// CHECK: ret ptr %[[VPTR]]
+
+// CHECK: define {{.*}}linkonce_odr{{.*}} ptr @{{.*}}__synthesizedBaseSetterAccessor{{.*}}
+// CHECK: %[[VPTRS:.*]] = getelementptr inbounds %struct.NonCopyableHolder
+// CHECK: ret ptr %[[VPTRS]]