CodeGen, Itanium: Properly dllimport RTTI data

We would blindly assume that RTTI data should have the same linkage as
the vtable because we didn't think the RTTI data was external.  This
oversight stemmed because we didn't take dllimport into account.

This fixes PR21512.

llvm-svn: 221511

1 files changed, 10 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 084fd3be5b3..66ea0f68448 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -2190,6 +2190,11 @@ ItaniumRTTIBuilder::GetAddrOfExternalRTTIDescriptor(QualType Ty) {
                                   /*Constant=*/true,
                                   llvm::GlobalValue::ExternalLinkage, nullptr,
                                   Name);
+    if (const RecordType *RecordTy = dyn_cast<RecordType>(Ty)) {
+      const CXXRecordDecl *RD = cast<CXXRecordDecl>(RecordTy->getDecl());
+      if (RD->hasAttr<DLLImportAttr>())
+        GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
+    }
   }
 
   return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
@@ -2312,7 +2317,11 @@ static bool ShouldUseExternalRTTIDescriptor(CodeGenModule &CGM,
 
     // FIXME: this may need to be reconsidered if the key function
     // changes.
-    return CGM.getVTables().isVTableExternal(RD);
+    if (CGM.getVTables().isVTableExternal(RD))
+      return true;
+
+    if (RD->hasAttr<DLLImportAttr>())
+      return true;
   }
 
   return false;