CxxInterop: use Unsafe*Pointer for move-only

Author: kavon

include/swift/Basic/LangOptions.h

@@ -328,6 +328,9 @@ namespace swift {
     /// when importing Swift modules that enable C++ interoperability.
     bool RequireCxxInteropToImportCxxInteropModule = true;
 
+    // Workaround for bug when building SwiftCompilerSources (rdar://128013193)
+    bool CxxInteropUseOpaquePointerForMoveOnly = false;
+
     /// On Darwin platforms, use the pre-stable ABI's mark bit for Swift
     /// classes instead of the stable ABI's bit. This is needed when
     /// targeting OSes prior to macOS 10.14.4 and iOS 12.2, where

include/swift/Option/FrontendOptions.td

@@ -943,6 +943,11 @@ def cxx_interop_disable_requirement_at_import :
   HelpText<"Do not require C++ interoperability to be enabled when importing a Swift module that enables C++ interoperability">,
   Flags<[FrontendOption, HelpHidden]>;
 
+def cxx_interop_use_opaque_pointer_for_moveonly :
+  Flag<["-"], "cxx-interop-use-opaque-pointer-for-moveonly">,
+  HelpText<"Testing flag that will be eliminated soon. Do not use.">,
+  Flags<[FrontendOption, HelpHidden]>;
+
 def use_malloc : Flag<["-"], "use-malloc">,
   HelpText<"Allocate internal data structures using malloc "
            "(for memory debugging)">;

lib/ClangImporter/ClangImporter.cpp

@@ -5797,16 +5797,9 @@ cloneBaseMemberDecl(ValueDecl *decl, DeclContext *newContext) {
   if (auto var = dyn_cast<VarDecl>(decl)) {
     auto oldContext = var->getDeclContext();
     auto oldTypeDecl = oldContext->getSelfNominalTypeDecl();
-    // If the base type is non-copyable, and non-copyable generics are disabled,
-    // we cannot synthesize the accessor, because its implementation would use
-    // `UnsafePointer<BaseTy>`.
-    // We cannot use `ty->isNoncopyable()` here because that would create a
-    // cyclic dependency between ModuleQualifiedLookupRequest and
-    // LookupConformanceInModuleRequest, so we check for the presence of
-    // move-only attribute that is implicitly added to non-copyable C++ types by
-    // ClangImporter.
+    // FIXME: this is a workaround for rdar://128013193
     if (oldTypeDecl->getAttrs().hasAttribute<MoveOnlyAttr>() &&
-        !context.LangOpts.hasFeature(Feature::NoncopyableGenerics))
+        context.LangOpts.CxxInteropUseOpaquePointerForMoveOnly)
       return nullptr;
 
     auto rawMemory = allocateMemoryForDecl<VarDecl>(var->getASTContext(),

lib/ClangImporter/ImportType.cpp

@@ -509,19 +509,12 @@ namespace {
         return importFunctionPointerLikeType(*type, pointeeType);
       }
 
-      // If non-copyable generics are disabled, we cannot specify
-      // UnsafePointer<T> with a non-copyable type T.
-      // We cannot use `ty->isNoncopyable()` here because that would create a
-      // cyclic dependency between ModuleQualifiedLookupRequest and
-      // LookupConformanceInModuleRequest, so we check for the presence of
-      // move-only attribute that is implicitly added to non-copyable C++ types
-      // by ClangImporter.
+      // FIXME: this is a workaround for rdar://128013193
       if (pointeeType && pointeeType->getAnyNominal() &&
           pointeeType->getAnyNominal()
               ->getAttrs()
               .hasAttribute<MoveOnlyAttr>() &&
-          !Impl.SwiftContext.LangOpts.hasFeature(
-              Feature::NoncopyableGenerics)) {
+          Impl.SwiftContext.LangOpts.CxxInteropUseOpaquePointerForMoveOnly) {
         auto opaquePointerDecl = Impl.SwiftContext.getOpaquePointerDecl();
         if (!opaquePointerDecl)
           return Type();

lib/Frontend/CompilerInvocation.cpp

@@ -1269,6 +1269,8 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.CxxInteropGettersSettersAsProperties = Args.hasArg(OPT_cxx_interop_getters_setters_as_properties);
   Opts.RequireCxxInteropToImportCxxInteropModule =
       !Args.hasArg(OPT_cxx_interop_disable_requirement_at_import);
+  Opts.CxxInteropUseOpaquePointerForMoveOnly =
+      Args.hasArg(OPT_cxx_interop_use_opaque_pointer_for_moveonly);
 
   Opts.VerifyAllSubstitutionMaps |= Args.hasArg(OPT_verify_all_substitution_maps);
 

test/Interop/Cxx/class/move-only/move-only-cxx-value-type-module-interface.swift

@@ -1,8 +1,4 @@
-// RUN: %target-swift-ide-test -print-module -module-to-print=MoveOnlyCxxValueType -I %S/Inputs -cxx-interoperability-mode=upcoming-swift -source-filename=x | %FileCheck %s --check-prefix=CHECK-NO-NCG
-// RUN: %target-swift-ide-test -print-module -module-to-print=MoveOnlyCxxValueType -I %S/Inputs -cxx-interoperability-mode=upcoming-swift -source-filename=x -enable-experimental-feature NoncopyableGenerics | %FileCheck %s --check-prefix=CHECK-NCG
+// RUN: %target-swift-ide-test -print-module -module-to-print=MoveOnlyCxxValueType -I %S/Inputs -cxx-interoperability-mode=upcoming-swift -source-filename=x | %FileCheck %s
 
-// CHECK-NO-NCG: func getNonCopyablePtr() -> OpaquePointer
-// CHECK-NO-NCG: func getNonCopyableDerivedPtr() -> OpaquePointer
-
-// CHECK-NCG: func getNonCopyablePtr() -> UnsafeMutablePointer<NonCopyable>
-// CHECK-NCG: func getNonCopyableDerivedPtr() -> UnsafeMutablePointer<NonCopyableDerived>
+// CHECK: func getNonCopyablePtr() -> UnsafeMutablePointer<NonCopyable>
+// CHECK: func getNonCopyableDerivedPtr() -> UnsafeMutablePointer<NonCopyableDerived>

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

@@ -1,8 +1,8 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift)
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature NoncopyableGenerics -D HAS_NONCOPYABLE_GENERICS)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -D HAS_NONCOPYABLE_GENERICS)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-5.9 -O)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-6 -O)
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-6 -O -enable-experimental-feature NoncopyableGenerics -D HAS_NONCOPYABLE_GENERICS)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-6 -O -D HAS_NONCOPYABLE_GENERICS)
 
 // REQUIRES: executable_test
 

test/Interop/Cxx/operators/move-only/move-only-synthesized-properties.swift

@@ -1,11 +1,11 @@
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-5.9)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-6)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift)
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -enable-experimental-feature NoncopyableGenerics -D HAS_NONCOPYABLE_GENERICS)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -D HAS_NONCOPYABLE_GENERICS)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-5.9 -O)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=swift-6 -O)
 // RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -O)
-// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -O -enable-experimental-feature NoncopyableGenerics -D HAS_NONCOPYABLE_GENERICS)
+// RUN: %target-run-simple-swift(-I %S/Inputs/ -cxx-interoperability-mode=upcoming-swift -O -D HAS_NONCOPYABLE_GENERICS)
 //
 // REQUIRES: executable_test
 

test/SILOptimizer/moveonly_optional_force_unwrap.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -enable-experimental-feature NoncopyableGenerics -emit-sil -verify %s
+// RUN: %target-swift-frontend -emit-sil -verify %s
 
 struct NC: ~Copyable {
     borrowing func borrow() {}