[interop] allow virtual methods only for the 'upcoming-swift' release

Author: hyp

lib/ClangImporter/ImportDecl.cpp

@@ -42,6 +42,7 @@
 #include "swift/Basic/PrettyStackTrace.h"
 #include "swift/Basic/Statistic.h"
 #include "swift/Basic/StringExtras.h"
+#include "swift/Basic/Version.h"
 #include "swift/ClangImporter/CXXMethodBridging.h"
 #include "swift/ClangImporter/ClangImporterRequests.h"
 #include "swift/ClangImporter/ClangModule.h"
@@ -3744,33 +3745,39 @@ namespace {
     Decl *VisitCXXMethodDecl(const clang::CXXMethodDecl *decl) {
       auto method = VisitFunctionDecl(decl);
       if (decl->isVirtual() && isa_and_nonnull<ValueDecl>(method)) {
-
-        if (auto dc = method->getDeclContext();
-            !decl->isPure() &&
-            isa_and_nonnull<NominalTypeDecl>(dc->getAsDecl())) {
-
-          // generates the __synthesizedVirtualCall_ C++ thunk
-          clang::CXXMethodDecl *cxxThunk = synthesizeCxxVirtualMethod(
-              *static_cast<ClangImporter *>(
-                  dc->getASTContext().getClangModuleLoader()),
-              decl->getParent(), decl->getParent(), decl);
-
-          // call the __synthesizedVirtualCall_ C++ thunk from a Swift thunk
-          if (Decl *swiftThunk =
-                  cxxThunk ? VisitCXXMethodDecl(cxxThunk) : nullptr;
-              isa_and_nonnull<FuncDecl>(swiftThunk)) {
-            // synthesize the body of the Swift method to call the swiftThunk
-            synthesizeForwardingThunkBody(cast<FuncDecl>(method),
-                                          cast<FuncDecl>(swiftThunk));
-            return method;
+        if (Impl.isCxxInteropCompatVersionAtLeast(
+                version::getUpcomingCxxInteropCompatVersion())) {
+          if (auto dc = method->getDeclContext();
+              !decl->isPure() &&
+              isa_and_nonnull<NominalTypeDecl>(dc->getAsDecl())) {
+
+            // generates the __synthesizedVirtualCall_ C++ thunk
+            clang::CXXMethodDecl *cxxThunk = synthesizeCxxVirtualMethod(
+                *static_cast<ClangImporter *>(
+                    dc->getASTContext().getClangModuleLoader()),
+                decl->getParent(), decl->getParent(), decl);
+
+            // call the __synthesizedVirtualCall_ C++ thunk from a Swift thunk
+            if (Decl *swiftThunk =
+                    cxxThunk ? VisitCXXMethodDecl(cxxThunk) : nullptr;
+                isa_and_nonnull<FuncDecl>(swiftThunk)) {
+              // synthesize the body of the Swift method to call the swiftThunk
+              synthesizeForwardingThunkBody(cast<FuncDecl>(method),
+                                            cast<FuncDecl>(swiftThunk));
+              return method;
+            }
           }
-        }
 
-        Impl.markUnavailable(
-            cast<ValueDecl>(method),
-            decl->isPure() ?
-            "virtual function is not available in Swift because it is pure" :
-            "virtual function is not available in Swift");
+          Impl.markUnavailable(
+              cast<ValueDecl>(method),
+              decl->isPure() ? "virtual function is not available in Swift "
+                               "because it is pure"
+                             : "virtual function is not available in Swift");
+        } else {
+          Impl.markUnavailable(
+              cast<ValueDecl>(method),
+              "virtual functions are not yet available in Swift");
+        }
       }
 
       if (Impl.SwiftContext.LangOpts.CxxInteropGettersSettersAsProperties ||

test/Interop/Cxx/class/inheritance/virtual-methods-irgen.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-emit-ir -I %S/Inputs -enable-experimental-cxx-interop %s -validate-tbd-against-ir=none | %FileCheck %s
+// RUN: %target-swift-emit-ir -I %S/Inputs -cxx-interoperability-mode=upcoming-swift %s -validate-tbd-against-ir=none | %FileCheck %s
 
 // FIXME: enable on Windows
 // XFAIL: OS=windows-msvc

test/Interop/Cxx/class/inheritance/virtual-methods-module-interface.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-ide-test -print-module -print-implicit-attrs -module-to-print=VirtualMethods -I %S/Inputs -source-filename=x -enable-experimental-cxx-interop | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -cxx-interoperability-mode=upcoming-swift -print-implicit-attrs -module-to-print=VirtualMethods -I %S/Inputs -source-filename=x | %FileCheck %s
 
 // CHECK: struct Base {
 // CHECK-NEXT:  init()

test/Interop/Cxx/class/inheritance/virtual-methods-typechecker.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -enable-experimental-cxx-interop
+// RUN: %target-typecheck-verify-swift -verify-ignore-unknown -I %S/Inputs -cxx-interoperability-mode=upcoming-swift
 
 import VirtualMethods