For dllexport class templates, export specializations of member functions (PR34849)

llvm-svn: 315025

2 files changed, 23 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 48fb2318e61..5b90557e799 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -6041,6 +6041,21 @@ static void checkDLLAttributeRedeclaration(Sema &S, NamedDecl *OldDecl,
            diag::warn_dllimport_dropped_from_inline_function)
         << NewDecl << OldImportAttr;
   }
+
+  // A specialization of a class template member function is processed here
+  // since it's a redeclaration. If the parent class is dllexport, the
+  // specialization inherits that attribute. This doesn't happen automatically
+  // since the parent class isn't instantiated until later.
+  if (IsSpecialization && isa<CXXMethodDecl>(NewDecl) && !NewImportAttr &&
+      !NewExportAttr) {
+    if (const DLLExportAttr *ParentExportAttr = cast<CXXMethodDecl>(NewDecl)
+                                             ->getParent()
+                                             ->getAttr<DLLExportAttr>()) {
+      DLLExportAttr *NewAttr = ParentExportAttr->clone(S.Context);
+      NewAttr->setInherited(true);
+      NewDecl->addAttr(NewAttr);
+    }
+  }
 }
 
 /// Given that we are within the definition of the given function,
diff --git a/clang/test/CodeGenCXX/dllexport.cpp b/clang/test/CodeGenCXX/dllexport.cpp
index bdef2eb06e6..a984b6d7ef1 100644
--- a/clang/test/CodeGenCXX/dllexport.cpp
+++ b/clang/test/CodeGenCXX/dllexport.cpp
@@ -831,6 +831,14 @@ template <typename T> struct ExplicitInstantiationTwoAttributes { void f() {} };
 template struct __declspec(dllexport) __declspec(dllimport) ExplicitInstantiationTwoAttributes<int>;
 // M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?f@?$ExplicitInstantiationTwoAttributes@H@@QAEXXZ"
 
+// Specializations of exported class template functions get exported.
+namespace pr34849 {
+template <typename T> struct __declspec(dllexport) ExportedClass { void foo(); };
+template<> void ExportedClass<int>::foo() {}
+template struct ExportedClass<int>;
+// M32-DAG: define dllexport x86_thiscallcc void @"\01?foo@?$ExportedClass@H@pr34849@@QAEXXZ"
+}
+
 
 //===----------------------------------------------------------------------===//
 // Classes with template base classes