[MS] Emit exported complete/vbase destructors

[rnk]

Summary

Fixes PR44205

I checked, and deleting destructors are not affected.

[hans]

Nice, thanks!

clang/lib/CodeGen/MicrosoftCXXABI.cpp

1349

The grammar looks funny here: "when the class was dllexported inlines are being exported".

[rnk]

clang/lib/CodeGen/MicrosoftCXXABI.cpp

1349

Thanks, too much editing leads to mistakes. =/ Cleaned up to:

// FIXME: To match MSVC, this should only be done when the class is exported
// with -fdllexport-inlines enabled.

clang/lib/CodeGen/MicrosoftCXXABI.cpp

llvm::GlobalValue::LinkageTypes MicrosoftCXXABI::getCXXDestructorLinkage(
   }
   llvm_unreachable("invalid dtor type");
 }
 
 void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
   // The TU defining a dtor is only guaranteed to emit a base destructor.  All
   // other destructor variants are delegating thunks.
   CGM.EmitGlobal(GlobalDecl(D, Dtor_Base));
+
+  // If the class is dllexported, emit the complete (vbase) destructor wherever
+  // the base dtor is emitted.
+  // FIXME: To match MSVC, this should only be done when the class is exported
+  // with -fdllexport-inlines enabled.
+  if (D->getParent()->getNumVBases() > 0 && D->hasAttr<DLLExportAttr>())
+    CGM.EmitGlobal(GlobalDecl(D, Dtor_Complete));
 }
 
 CharUnits
 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
 
   if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
     // Complete destructors take a pointer to the complete object as a

clang/test/CodeGenCXX/dllexport-dtor-thunks.cpp

 // RUN: %clang_cc1 -mconstructor-aliases -fms-extensions %s -emit-llvm -o - -triple x86_64-windows-msvc | FileCheck %s
 
+namespace test1 {
+struct A { ~A(); };
+struct __declspec(dllexport) B : virtual A { };
+// CHECK: define weak_odr dso_local dllexport void @"??1B@test1@@QEAA@XZ"
+// CHECK: define weak_odr dso_local dllexport void @"??_DB@test1@@QEAAXXZ"
+}
+
 struct __declspec(dllexport) A { virtual ~A(); };
 struct __declspec(dllexport) B { virtual ~B(); };
 struct __declspec(dllexport) C : A, B { virtual ~C(); };
 C::~C() {}
 
 // CHECK: define dso_local dllexport void @"??1C@@UEAA@XZ"
 // This thunk should *not* be dllexport.
 // CHECK: define linkonce_odr dso_local i8* @"??_EC@@W7EAAPEAXI@Z"

clang/test/CodeGenCXX/dllimport-dtor-thunks.cpp

 
 // Non-virtually inherits from a non-dllimport base class. We should again call
 // the derived base constructor directly. No need for the complete (aka vbase)
 // destructor.
 struct __declspec(dllimport) ImportOverrideVDtor : public BaseClass {
   virtual ~ImportOverrideVDtor() {}
 };
 
-// Virtually inherits from a non-dllimport base class. This time we need to call
-// the complete destructor and emit it inline. It's not exported from the DLL,
-// and it must be emitted.
+// Virtually inherits from a non-dllimport base class. In this case, we can
+// expect the DLL to provide a definition of the complete dtor. See
+// dllexport-dtor-thunks.cpp.
 struct __declspec(dllimport) ImportVBaseOverrideVDtor
     : public virtual BaseClass {
   virtual ~ImportVBaseOverrideVDtor() {}
 };
 
 extern "C" void testit() {
   ImportIntroVDtor t1;
   ImportOverrideVDtor t2;