Backport some fixes for C++ interop tests on 5.4

lib/ClangImporter/ClangImporter.cpp

@@ -520,21 +520,44 @@ importer::getNormalInvocationArguments(
     invocationArgStrs.push_back(
         "-Werror=non-modular-include-in-framework-module");
 
+  bool EnableCXXInterop = LangOpts.EnableCXXInterop;
+
   if (LangOpts.EnableObjCInterop) {
-    bool EnableCXXInterop = LangOpts.EnableCXXInterop;
-    invocationArgStrs.insert(
-        invocationArgStrs.end(),
-        {"-x", EnableCXXInterop ? "objective-c++" : "objective-c",
-         EnableCXXInterop ? "-std=gnu++17" : "-std=gnu11", "-fobjc-arc"});
+    invocationArgStrs.insert(invocationArgStrs.end(), {"-fobjc-arc"});
     // TODO: Investigate whether 7.0 is a suitable default version.
     if (!triple.isOSDarwin())
       invocationArgStrs.insert(invocationArgStrs.end(),
                                {"-fobjc-runtime=ios-7.0"});
+    invocationArgStrs.insert(invocationArgStrs.end(), {
+      "-x", EnableCXXInterop ? "objective-c++" : "objective-c"
+    });
   } else {
-    bool EnableCXXInterop = LangOpts.EnableCXXInterop;
-    invocationArgStrs.insert(invocationArgStrs.end(),
-                             {"-x", EnableCXXInterop ? "c++" : "c",
-                              EnableCXXInterop ? "-std=gnu++17" : "-std=gnu11"});
+    invocationArgStrs.insert(invocationArgStrs.end(), {
+      "-x", EnableCXXInterop ? "c++" : "c"
+    });
+  }
+
+  {
+    const clang::LangStandard &stdcxx =
+#if defined(CLANG_DEFAULT_STD_CXX)
+        *clang::LangStandard::getLangStandardForName(CLANG_DEFAULT_STD_CXX);
+#else
+        clang::LangStandard::getLangStandardForKind(
+            clang::LangStandard::lang_gnucxx14);
+#endif
+
+    const clang::LangStandard &stdc =
+#if defined(CLANG_DEFAULT_STD_C)
+        *clang::LangStandard::getLangStandardForName(CLANG_DEFAULT_STD_C);
+#else
+        clang::LangStandard::getLangStandardForKind(
+            clang::LangStandard::lang_gnu11);
+#endif
+
+    invocationArgStrs.insert(invocationArgStrs.end(), {
+      (Twine("-std=") + StringRef(EnableCXXInterop ? stdcxx.getName()
+                                                   : stdc.getName())).str()
+    });
   }
 
   // Set C language options.

test/ClangImporter/cxx_interop.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -typecheck %s -I %S/Inputs/custom-modules -module-cache-path %t -enable-cxx-interop
+// RUN: %target-swiftxx-frontend -typecheck %s -I %S/Inputs/custom-modules
 
 import CXXInterop
 

test/ClangImporter/cxx_interop_ir.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -module-name cxx_ir -I %S/Inputs/custom-modules -module-cache-path %t -enable-cxx-interop -emit-ir -o - -primary-file %s | %FileCheck %s
+// RUN: %target-swiftxx-frontend -module-name cxx_ir -I %S/Inputs/custom-modules -emit-ir -o - -primary-file %s | %FileCheck %s
 
 import CXXInterop
 

test/ClangImporter/enum-cxx.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -emit-ir -primary-file %s -I %S/Inputs/custom-modules -module-cache-path %t -enable-cxx-interop -o - | %FileCheck %s
+// RUN: %target-swiftxx-frontend -emit-ir -primary-file %s -I %S/Inputs/custom-modules -o - | %FileCheck %s
 
 import CXXInterop
 

test/Interop/C/function/emit-called-inline-function-irgen.swift

@@ -6,7 +6,7 @@
 
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -I %S/Inputs -Xcc -std=c99 -emit-ir -o - | %FileCheck %s -check-prefix C99 --implicit-check-not notCalled
-// RUN: %target-swift-frontend %s -I %S/Inputs -enable-cxx-interop -emit-ir -o - | %FileCheck %s -check-prefix CXX --implicit-check-not notCalled
+// RUN: %target-swiftxx-frontend %s -I %S/Inputs -emit-ir -o - | %FileCheck %s -check-prefix CXX --implicit-check-not notCalled
 
 import EmitCalledInlineFunction
 

test/Interop/Cxx/class/Inputs/module.modulemap

@@ -1,47 +1,59 @@
 module AccessSpecifiers {
   header "access-specifiers.h"
+  requires cplusplus
 }
 
 module TypeClassification {
   header "type-classification.h"
+  requires cplusplus
 }
 
 module Constructors {
   header "constructors.h"
+  requires cplusplus
 }
 
 module ConstructorsObjC {
   header "constructors-objc.h"
+  requires cplusplus
 }
 
 module LoadableTypes {
   header "loadable-types.h"
+  requires cplusplus
 }
 
 module MemberwiseInitializer {
   header "memberwise-initializer.h"
+  requires cplusplus
 }
 
 module MemoryLayout {
   header "memory-layout.h"
+  requires cplusplus
 }
 
 module MemberVariables {
   header "member-variables.h"
+  requires cplusplus
 }
 
 module ProtocolConformance {
   header "protocol-conformance.h"
+  requires cplusplus
 }
 
 module SynthesizedInitializers {
   header "synthesized-initializers.h"
+  requires cplusplus
 }
 
 module DebugInfo {
   header "debug-info.h"
+  requires cplusplus
 }
 
 module NestedRecords {
   header "nested-records.h"
+  requires cplusplus
 }

test/Interop/Cxx/class/constructors-silgen.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -I %S/Inputs -enable-cxx-interop -emit-silgen %s | %FileCheck %s
+// RUN: %target-swiftxx-frontend -I %S/Inputs -emit-silgen %s | %FileCheck %s
 
 import Constructors
 

test/Interop/Cxx/class/debug-info-irgen.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -enable-cxx-interop -I %S/Inputs %s -emit-ir -g | %FileCheck %s
+// RUN: %target-swiftxx-frontend -I %S/Inputs %s -emit-ir -g | %FileCheck %s
 
 // Validate that we don't crash when trying to deserialize C++ type debug info.
 // Note, however, that the actual debug info is not generated, see SR-13223.

test/Interop/Cxx/class/memory-layout-silgen.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -I %S/Inputs -enable-cxx-interop -emit-ir -o - %s | %FileCheck %s
+// RUN: %target-swiftxx-frontend -I %S/Inputs -emit-ir -o - %s | %FileCheck %s
 
 import MemoryLayout
 

test/Interop/Cxx/class/type-classification-non-trivial-irgen.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -enable-cxx-interop -I %S/Inputs %s -emit-ir | %FileCheck %s
+// RUN: %target-swiftxx-frontend -I %S/Inputs %s -emit-ir | %FileCheck %s
 
 // Verify that non-trival/address-only C++ classes are constructed and accessed
 // correctly. Make sure that we correctly IRGen functions that construct

test/Interop/Cxx/class/type-classification-non-trivial-silgen.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -I %S/Inputs -enable-cxx-interop -emit-silgen %s | %FileCheck %s
+// RUN: %target-swiftxx-frontend -I %S/Inputs -emit-silgen %s | %FileCheck %s
 
 import TypeClassification
 

test/Interop/Cxx/enum/Inputs/module.modulemap

@@ -1,3 +1,4 @@
 module BoolEnums {
   header "bool-enums.h"
+  requires cplusplus
 }

test/Interop/Cxx/extern-var/Inputs/module.modulemap

@@ -1,3 +1,4 @@
 module ExternVar {
   header "extern-var.h"
+  requires cplusplus
 }

test/Interop/Cxx/extern-var/extern-var.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/extern-var.cpp -I %S/Inputs -o %t/extern-var.o
+// RUN: %target-clangxx -c %S/Inputs/extern-var.cpp -I %S/Inputs -o %t/extern-var.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/extern-var %t/extern-var.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/extern-var
 // RUN: %target-run %t/extern-var

test/Interop/Cxx/implementation-only-imports/Inputs/module.modulemap

@@ -1,24 +1,29 @@
 module UserA {
     header "user-a.h"
     export *
+    requires cplusplus
 }
 
 module UserB {
     header "user-b.h"
     export *
+    requires cplusplus
 }
 
 module UserC {
     header "user-c.h"
     export *
+    requires cplusplus
 }
 
 module DeclA {
     header "decl-a.h"
     export *
+    requires cplusplus
 }
 
 module DeclB {
     header "decl-b.h"
     export *
+    requires cplusplus
 }

test/Interop/Cxx/implementation-only-imports/check-constructor-visibility-inversed.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s -enable-cxx-interop
+// RUN: %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s
 
 // Swift should consider all sources for a decl and recognize that the
 // decl is not hidden behind @_implementationOnly in all modules.

test/Interop/Cxx/implementation-only-imports/check-constructor-visibility.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s -enable-cxx-interop
+// RUN: %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s
 
 // Swift should consider all sources for a decl and recognize that the
 // decl is not hidden behind @_implementationOnly in all modules.

test/Interop/Cxx/implementation-only-imports/check-decls-are-identical.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: not %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs -enable-cxx-interop %s 2>&1 | %FileCheck %s
+// RUN: not %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s 2>&1 | %FileCheck %s
 
 // This test checks that Swift recognizes that the DeclA and DeclB provide
 // different implementations for `getFortySomething()`

test/Interop/Cxx/implementation-only-imports/check-function-transitive-visibility-inversed.swift

@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: mkdir %t/use_module_a %t/use_module_b
-// RUN: %target-swift-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_a/UseModuleA.swiftmodule %S/Inputs/use-module-a.swift -I %S/Inputs -enable-cxx-interop
-// RUN: %target-swift-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_b/UseModuleB.swiftmodule %S/Inputs/use-module-b.swift -I %S/Inputs -enable-cxx-interop
+// RUN: %target-swiftxx-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_a/UseModuleA.swiftmodule %S/Inputs/use-module-a.swift -I %S/Inputs
+// RUN: %target-swiftxx-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_b/UseModuleB.swiftmodule %S/Inputs/use-module-b.swift -I %S/Inputs
 
-// RUN: %target-swift-frontend -typecheck -swift-version 5 -I %t/use_module_a -I %t/use_module_b -I %S/Inputs -enable-cxx-interop %s
+// RUN: %target-swiftxx-frontend -typecheck -swift-version 5 -I %t/use_module_a -I %t/use_module_b -I %S/Inputs %s
 
 // Swift should consider all sources for a decl and recognize that the
 // decl is not hidden behind @_implementationOnly in all modules.

test/Interop/Cxx/implementation-only-imports/check-function-transitive-visibility.swift

@@ -1,9 +1,9 @@
 // RUN: %empty-directory(%t)
 // RUN: mkdir %t/use_module_a %t/use_module_b
-// RUN: %target-swift-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_a/UseModuleA.swiftmodule %S/Inputs/use-module-a.swift -I %S/Inputs -enable-cxx-interop
-// RUN: %target-swift-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_b/UseModuleB.swiftmodule %S/Inputs/use-module-b.swift -I %S/Inputs -enable-cxx-interop
+// RUN: %target-swiftxx-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_a/UseModuleA.swiftmodule %S/Inputs/use-module-a.swift -I %S/Inputs
+// RUN: %target-swiftxx-frontend -enable-library-evolution -swift-version 5 -emit-module -o %t/use_module_b/UseModuleB.swiftmodule %S/Inputs/use-module-b.swift -I %S/Inputs
 
-// RUN: %target-swift-frontend -typecheck -swift-version 5 -I %t/use_module_a -I %t/use_module_b -I %S/Inputs -enable-cxx-interop %s
+// RUN: %target-swiftxx-frontend -typecheck -swift-version 5 -I %t/use_module_a -I %t/use_module_b -I %S/Inputs %s
 
 
 // Swift should consider all sources for a decl and recognize that the

test/Interop/Cxx/implementation-only-imports/check-function-visibility-inversed.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs -enable-cxx-interop %s
+// RUN: %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s
 
 // Swift should consider all sources for a decl and recognize that the
 // decl is not hidden behind @_implementationOnly in all modules.

test/Interop/Cxx/implementation-only-imports/check-function-visibility.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs -enable-cxx-interop %s
+// RUN: %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s
 
 // Swift should consider all sources for a decl and recognize that the
 // decl is not hidden behind @_implementationOnly in all modules.

test/Interop/Cxx/implementation-only-imports/check-operator-visibility-inversed.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s -enable-cxx-interop
+// RUN: %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s
 
 // Swift should consider all sources for a decl and recognize that the
 // decl is not hidden behind @_implementationOnly in all modules.

test/Interop/Cxx/implementation-only-imports/check-operator-visibility.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s -enable-cxx-interop
+// RUN: %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s
 
 // Swift should consider all sources for a decl and recognize that the
 // decl is not hidden behind @_implementationOnly in all modules.

test/Interop/Cxx/implementation-only-imports/skip-forward-declarations.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: not %target-swift-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs -enable-cxx-interop %s 2>&1 | %FileCheck %s
+// RUN: not %target-swiftxx-frontend -emit-module -o %t/FortyTwo.swiftmodule -I %S/Inputs %s 2>&1 | %FileCheck %s
 
 // This test checks that forward declarations are not considered
 // when determining the visibility of the decl.

test/Interop/Cxx/operators/Inputs/module.modulemap

@@ -1,15 +1,19 @@
 module MemberInline {
   header "member-inline.h"
+  requires cplusplus
 }
 
 module MemberOutOfLine {
   header "member-out-of-line.h"
+  requires cplusplus
 }
 
 module NonMemberInline {
   header "non-member-inline.h"
+  requires cplusplus
 }
 
 module NonMemberOutOfLine {
   header "non-member-out-of-line.h"
+  requires cplusplus
 }

test/Interop/Cxx/operators/member-out-of-line.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/member-out-of-line.cpp -I %S/Inputs -o %t/member-out-of-line.o -std=c++17
+// RUN: %target-clangxx -c %S/Inputs/member-out-of-line.cpp -I %S/Inputs -o %t/member-out-of-line.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/member-out-of-line %t/member-out-of-line.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/member-out-of-line
 // RUN: %target-run %t/member-out-of-line

test/Interop/Cxx/operators/non-member-out-of-line.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/non-member-out-of-line.cpp -I %S/Inputs -o %t/non-member-out-of-line.o -std=c++17
+// RUN: %target-clangxx -c %S/Inputs/non-member-out-of-line.cpp -I %S/Inputs -o %t/non-member-out-of-line.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/non-member-out-of-line %t/non-member-out-of-line.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/non-member-out-of-line
 // RUN: %target-run %t/non-member-out-of-line

test/Interop/Cxx/reference/Inputs/module.modulemap

@@ -1,3 +1,4 @@
 module Reference {
   header "reference.h"
+  requires cplusplus
 }

test/Interop/Cxx/reference/reference.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/reference.cpp -I %S/Inputs -o %t/reference.o -std=c++17
+// RUN: %target-clangxx -c %S/Inputs/reference.cpp -I %S/Inputs -o %t/reference.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/reference %t/reference.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/reference
 // RUN: %target-run %t/reference

test/Interop/Cxx/static/Inputs/module.modulemap

@@ -1,19 +1,24 @@
 module StaticVar {
   header "static-var.h"
+  requires cplusplus
 }
 
 module StaticLocalVar {
   header "static-local-var.h"
+  requires cplusplus
 }
 
 module StaticMemberVar {
   header "static-member-var.h"
+  requires cplusplus
 }
 
 module InlineStaticMemberVar {
   header "inline-static-member-var.h"
+  requires cplusplus
 }
 
 module StaticMemberFunc {
   header "static-member-func.h"
+  requires cplusplus
 }

test/Interop/Cxx/static/constexpr-static-member-var.swift

@@ -1,6 +1,7 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/static-member-var.cpp -I %S/Inputs -o %t/static-member-var.o -std=c++17
-// RUN: %target-build-swift %s -I %S/Inputs -o %t/statics %t/static-member-var.o -Xfrontend -enable-cxx-interop
+// RUN: %target-clangxx -c %S/Inputs/static-member-var.cpp -I %S/Inputs -o %t/static-member-var.o
+// NOTE: we must use `-O` here to ensure that the constexpr value is inlined and no undefined reference remains.
+// RUN: %target-build-swift -O %s -I %S/Inputs -o %t/statics %t/static-member-var.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/statics
 // RUN: %target-run %t/statics
 //

test/Interop/Cxx/static/inline-static-member-var.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/inline-static-member-var.cpp -I %S/Inputs -o %t/inline-static-member-var.o -std=c++17
+// RUN: %target-clangxx -c %S/Inputs/inline-static-member-var.cpp -I %S/Inputs -o %t/inline-static-member-var.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/statics %t/inline-static-member-var.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/statics
 // RUN: %target-run %t/statics 2&>1

test/Interop/Cxx/static/static-local-var.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-clang -c %S/Inputs/static-local-var.cpp -I %S/Inputs -o %t/static-local-var.o
+// RUN: %target-clangxx -c %S/Inputs/static-local-var.cpp -I %S/Inputs -o %t/static-local-var.o
 // RUN: %target-build-swift %s -I %S/Inputs -o %t/statics %t/static-local-var.o -Xfrontend -enable-cxx-interop
 // RUN: %target-codesign %t/statics
 // RUN: %target-run %t/statics