From b4af165b49b3e9196932c7fca4462d2bfc707657 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Fri, 2 Dec 2016 22:46:18 +0000
Subject: [PATCH] CodeGen: export typeinfo and typeinfo name on itanium

When a C++ record is marked with dllexport mark both the typeinfo and the
typeinfo name as being exported.  Handle dllimport as the inverse.  This applies
to the itanium environment and not the MinGW environment.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@288546 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/ItaniumCXXABI.cpp                 | 30 +++++++++++++++----
 test/CodeGenCXX/windows-itanium-type-info.cpp | 21 ++++++++++++-
 2 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index 088454647c..48d47d2359 100644
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -2911,16 +2911,18 @@ static llvm::GlobalVariable::LinkageTypes getTypeInfoLinkage(CodeGenModule &CGM,
 
   case VisibleNoLinkage:
   case ExternalLinkage:
-    if (!CGM.getLangOpts().RTTI) {
-      // RTTI is not enabled, which means that this type info struct is going
-      // to be used for exception handling. Give it linkonce_odr linkage.
+    // RTTI is not enabled, which means that this type info struct is going
+    // to be used for exception handling. Give it linkonce_odr linkage.
+    if (!CGM.getLangOpts().RTTI)
       return llvm::GlobalValue::LinkOnceODRLinkage;
-    }
 
     if (const RecordType *Record = dyn_cast<RecordType>(Ty)) {
       const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
       if (RD->hasAttr<WeakAttr>())
         return llvm::GlobalValue::WeakODRLinkage;
+      if (CGM.getTriple().isWindowsItaniumEnvironment())
+        if (RD->hasAttr<DLLImportAttr>())
+          return llvm::GlobalValue::ExternalLinkage;
       if (RD->isDynamicClass()) {
         llvm::GlobalValue::LinkageTypes LT = CGM.getVTableLinkage(RD);
         // MinGW won't export the RTTI information when there is a key function.
@@ -3122,10 +3124,26 @@ llvm::Constant *ItaniumRTTIBuilder::BuildTypeInfo(QualType Ty, bool Force,
     llvmVisibility = llvm::GlobalValue::HiddenVisibility;
   else
     llvmVisibility = CodeGenModule::GetLLVMVisibility(Ty->getVisibility());
+
   TypeName->setVisibility(llvmVisibility);
   GV->setVisibility(llvmVisibility);
-  if (DLLExport)
-    GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
+
+  if (CGM.getTriple().isWindowsItaniumEnvironment()) {
+    auto RD = Ty->getAsCXXRecordDecl();
+    if (DLLExport || (RD && RD->hasAttr<DLLExportAttr>())) {
+      TypeName->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
+      GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
+    } else if (RD && RD->hasAttr<DLLImportAttr>()) {
+      TypeName->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
+      GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
+
+      // Because the typename and the typeinfo are DLL import, convert them to
+      // declarations rather than definitions.  The initializers still need to
+      // be constructed to calculate the type for the declarations.
+      TypeName->setInitializer(nullptr);
+      GV->setInitializer(nullptr);
+    }
+  }
 
   return llvm::ConstantExpr::getBitCast(GV, CGM.Int8PtrTy);
 }
diff --git a/test/CodeGenCXX/windows-itanium-type-info.cpp b/test/CodeGenCXX/windows-itanium-type-info.cpp
index 206e7c3e2f..ecc227d5b6 100644
--- a/test/CodeGenCXX/windows-itanium-type-info.cpp
+++ b/test/CodeGenCXX/windows-itanium-type-info.cpp
@@ -9,5 +9,24 @@ public:
 __fundamental_type_info::~__fundamental_type_info() {}
 }
 
-// CHECK: @_ZTIi = dllexport constant
+struct __declspec(dllimport) base {
+  virtual void method();
+};
+struct __declspec(dllexport) derived : base {
+  virtual ~derived();
+};
+derived::~derived() {
+  method();
+}
+
+// CHECK-DAG: @_ZTIi = dllexport constant
+// CHECK-DAG: @_ZTSi = dllexport constant
+
+// CHECK-DAG: @_ZTI7derived = dllexport constant
+// CHECK-DAG: @_ZTS7derived = dllexport constant
+// CHECK-DAG: @_ZTV7derived = dllexport unnamed_addr constant
+
+// CHECK-DAG: @_ZTI4base = external dllimport constant
+// CHECK-DAG: @_ZTS4base = external dllimport constant
+// CHECK-NOT: @_ZTV4base = external dllimport constant
 
-- 
2.40.0