Itanium ABI: Update getAddrOfVTable to set the DLL storage class for vtables

[hans]

Summary

This corresponds to the same change for the MS ABI in r209908 and makes us pass more of Nico's tests.

[rnk]

lgtm

test/CodeGenCXX/dllimport.cpp

530 ↗

(On Diff #10025)

Can you test the case where the vtable is external? A class with a key function at -O0 should do.

In related news, we don't appear to emit available_externally vtables for classes with key functions at -O1. That seems like a bad missed optimization.

[hans]

Closed by commit rL210054 (authored by @hans).

cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp

llvm::GlobalVariable *ItaniumCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
 
   ItaniumVTableContext &VTContext = CGM.getItaniumVTableContext();
   llvm::ArrayType *ArrayType = llvm::ArrayType::get(
       CGM.Int8PtrTy, VTContext.getVTableLayout(RD).getNumVTableComponents());
 
   VTable = CGM.CreateOrReplaceCXXRuntimeVariable(
       Name, ArrayType, llvm::GlobalValue::ExternalLinkage);
   VTable->setUnnamedAddr(true);
+
+  if (RD->hasAttr<DLLImportAttr>())
+    VTable->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
+  else if (RD->hasAttr<DLLExportAttr>())
+    VTable->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
+
   return VTable;
 }
 
 llvm::Value *ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
                                                       GlobalDecl GD,
                                                       llvm::Value *This,
                                                       llvm::Type *Ty) {
   GD = GD.getCanonicalDecl();

cfe/trunk/test/CodeGenCXX/dllexport.cpp

 
 struct __declspec(dllexport) W { virtual void foo() {} };
 // Default ctor:
 // M32-DAG: define weak_odr dllexport x86_thiscallcc %struct.W* @"\01??0W@@QAE@XZ"
 // Copy ctor:
 // M32-DAG: define weak_odr dllexport x86_thiscallcc %struct.W* @"\01??0W@@QAE@ABU0@@Z"
 // vftable:
 // M32-DAG: @"\01??_7W@@6B@" = weak_odr dllexport unnamed_addr constant [1 x i8*] [i8* bitcast (void (%struct.W*)* @"\01?foo@W@@UAEXXZ" to i8*)]
+// G32-DAG: @_ZTV1W = weak_odr dllexport unnamed_addr constant [3 x i8*] [i8* null, i8* bitcast ({ i8*, i8* }* @_ZTI1W to i8*), i8* bitcast (void (%struct.W*)* @_ZN1W3fooEv to i8*)]
 
 struct __declspec(dllexport) X : public virtual W {};
 // vbtable:
 // M32-DAG: @"\01??_8X@@7B@" = weak_odr dllexport unnamed_addr constant [2 x i32] [i32 0, i32 4]
 
 struct __declspec(dllexport) Y {
   // Move assignment operator:
   // M32-DAG: define weak_odr dllexport x86_thiscallcc nonnull %struct.Y* @"\01??4Y@@QAEAAU0@$$QAU0@@Z"

cfe/trunk/test/CodeGenCXX/dllimport.cpp

 USE(inlineDef)
 
 // inline attributes
 // MSC-DAG: declare dllimport void @"\01?noinline@@YAXXZ"()
 // GNU-DAG: declare dllimport void @_Z8noinlinev()
 __declspec(dllimport) __attribute__((noinline)) inline void noinline() {}
 USE(noinline)
 
-// MSC-NOT: @"\01?alwaysInline@@YAXXZ"()
-// GNU-NOT: @_Z12alwaysInlinev()
-__declspec(dllimport) __attribute__((always_inline)) inline void alwaysInline() {}
-USE(alwaysInline)
-
 // Redeclarations
 // MSC-DAG: declare dllimport void @"\01?redecl1@@YAXXZ"()
 // GNU-DAG: declare dllimport void @_Z7redecl1v()
 __declspec(dllimport) void redecl1();
 __declspec(dllimport) void redecl1();
 USE(redecl1)
 
 // NB: MSC issues a warning and makes redecl2/redecl3 dllexport. We follow GCC

 // MO1-DAG: define available_externally dllimport x86_thiscallcc void @"\01?foo@?$U@H@@QAEXXZ"
 struct __declspec(dllimport) V : public U<int> { };
 USEMEMFUNC(V, foo)
 
 struct __declspec(dllimport) W { virtual void foo() {} };
 USECLASS(W)
 // vftable:
 // MO1-DAG: @"\01??_7W@@6B@" = available_externally dllimport unnamed_addr constant [1 x i8*] [i8* bitcast (void (%struct.W*)* @"\01?foo@W@@UAEXXZ" to i8*)]
+// GO1-DAG: @_ZTV1W = available_externally dllimport unnamed_addr constant [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.W*)* @_ZN1W3fooEv to i8*)]
+
+struct __declspec(dllimport) KeyFuncClass {
+  constexpr KeyFuncClass() {}
+  virtual void foo();
+};
+constexpr KeyFuncClass keyFuncClassVar;
+// G32-DAG: @_ZTV12KeyFuncClass = external dllimport unnamed_addr constant [3 x i8*]
 
 struct __declspec(dllimport) X : public virtual W {};
 USECLASS(X)
 // vbtable:
 // MO1-DAG: @"\01??_8X@@7B@" = available_externally dllimport unnamed_addr constant [2 x i32] [i32 0, i32 4]
 
 struct __declspec(dllimport) Y {
   int x;
namespace Vtordisp {
   template <typename T>
   class __declspec(dllimport) C : virtual public Base {
   public:
     C() {}
     virtual void f() {}
   };
   template class C<char>;
 }
+
+//===----------------------------------------------------------------------===//
+// Negative checks
+//===----------------------------------------------------------------------===//
+
+// These checks are at the end to avoid interference with the DAG checks.
+
+// MSC-NOT: @"\01?alwaysInline@@YAXXZ"()
+// GNU-NOT: @_Z12alwaysInlinev()
+__declspec(dllimport) __attribute__((always_inline)) inline void alwaysInline() {}
+USE(alwaysInline)