MS ABI: Propagate class-level DLL attributes to class template specialization bases (PR11170)
Consider the following code:
template <typename T> class Base {};
class __declspec(dllexport) class Derived : public Base<int> {}
When the base of an exported or imported class is a class template
specialization, MSVC will propagate the dll attribute to the base.
In the example code, Base<int> becomes a dllexported class.
This commit makes Clang do the proopagation when the base hasn't been
instantiated yet, and warns about it being unsupported otherwise.
This is different from MSVC, which allows changing a specialization
back and forth between dllimport and dllexport and seems to let the
last one win. Changing the dll attribute after instantiation would be
hard for us, and doesn't seem to come up in practice, so I think this
is a reasonable limitation to have.
MinGW doesn't do this kind of propagation.
Differential Revision: http://reviews.llvm.org/D4264
llvm-svn: 211725
diff --git a/clang/test/CodeGenCXX/dllexport.cpp b/clang/test/CodeGenCXX/dllexport.cpp
index 114e5a7..0090d95 100644
--- a/clang/test/CodeGenCXX/dllexport.cpp
+++ b/clang/test/CodeGenCXX/dllexport.cpp
@@ -582,3 +582,101 @@
USEMEMFUNC(ExplicitlySpecializedClassTemplate<void*>, f);
// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?f@?$ExplicitlySpecializedClassTemplate@PAX@@QAEXXZ"
// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN34ExplicitlySpecializedClassTemplateIPvE1fEv
+
+//===----------------------------------------------------------------------===//
+// Classes with template base classes
+//===----------------------------------------------------------------------===//
+
+template <typename T> struct ClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllexport) ExportedClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllimport) ImportedClassTemplate { void func() {} };
+
+template <typename T> struct ExplicitlySpecializedTemplate { void func() {} };
+template <> struct ExplicitlySpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyExportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllexport) ExplicitlyExportSpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyImportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllimport) ExplicitlyImportSpecializedTemplate<int> { void func() {} };
+
+template <typename T> struct ExplicitlyInstantiatedTemplate { void func() {} };
+template struct ExplicitlyInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyExportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllexport) ExplicitlyExportInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyImportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllimport) ExplicitlyImportInstantiatedTemplate<int>;
+
+
+// MS: ClassTemplate<int> gets exported.
+struct __declspec(dllexport) DerivedFromTemplate : public ClassTemplate<int> {};
+USEMEMFUNC(ClassTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ClassTemplate@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIiE4funcEv
+
+// ExportedTemplate is explicitly exported.
+struct __declspec(dllexport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN21ExportedClassTemplateIiE4funcEv
+
+// ImportedClassTemplate is explicitly imported.
+struct __declspec(dllexport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+USEMEMFUNC(ImportedClassTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ImportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: declare dllimport x86_thiscallcc void @_ZN21ImportedClassTemplateIiE4funcEv
+
+// Base class already instantiated without dll attribute.
+struct DerivedFromTemplateD : public ClassTemplate<double> {};
+struct __declspec(dllexport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+USEMEMFUNC(ClassTemplate<double>, func)
+// M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?func@?$ClassTemplate@N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIdE4funcEv
+
+// MS: Base class already instantiated with different dll attribute.
+struct __declspec(dllimport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+struct __declspec(dllexport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+USEMEMFUNC(ClassTemplate<bool>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ClassTemplate@_N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIbE4funcEv
+
+// Base class already specialized without dll attribute.
+struct __declspec(dllexport) DerivedFromExplicitlySpecializedTemplate : public ExplicitlySpecializedTemplate<int> {};
+USEMEMFUNC(ExplicitlySpecializedTemplate<int>, func)
+// M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?func@?$ExplicitlySpecializedTemplate@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN29ExplicitlySpecializedTemplateIiE4funcEv
+
+// Base class alredy specialized with export attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyExportSpecializedTemplate : public ExplicitlyExportSpecializedTemplate<int> {};
+USEMEMFUNC(ExplicitlyExportSpecializedTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExplicitlyExportSpecializedTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN35ExplicitlyExportSpecializedTemplateIiE4funcEv
+
+// Base class already specialized with import attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyImportSpecializedTemplate : public ExplicitlyImportSpecializedTemplate<int> {};
+USEMEMFUNC(ExplicitlyImportSpecializedTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ExplicitlyImportSpecializedTemplate@H@@QAEXXZ"
+// G32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @_ZN35ExplicitlyImportSpecializedTemplateIiE4funcEv
+
+// Base class already instantiated without dll attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyInstantiatedTemplate : public ExplicitlyInstantiatedTemplate<int> {};
+USEMEMFUNC(ExplicitlyInstantiatedTemplate<int>, func)
+// M32-DAG: define weak_odr x86_thiscallcc void @"\01?func@?$ExplicitlyInstantiatedTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr x86_thiscallcc void @_ZN30ExplicitlyInstantiatedTemplateIiE4funcEv
+
+// Base class already instantiated with export attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyExportInstantiatedTemplate : public ExplicitlyExportInstantiatedTemplate<int> {};
+USEMEMFUNC(ExplicitlyExportInstantiatedTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExplicitlyExportInstantiatedTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN36ExplicitlyExportInstantiatedTemplateIiE4funcEv
+
+// Base class already instantiated with import attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyImportInstantiatedTemplate : public ExplicitlyImportInstantiatedTemplate<int> {};
+USEMEMFUNC(ExplicitlyImportInstantiatedTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ExplicitlyImportInstantiatedTemplate@H@@QAEXXZ"
+// G32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @_ZN36ExplicitlyImportInstantiatedTemplateIiE4funcEv
+
+// MS: A dll attribute propagates through multiple levels of instantiation.
+template <typename T> struct TopClass { void func() {} };
+template <typename T> struct MiddleClass : public TopClass<T> { };
+struct __declspec(dllexport) BottomClas : public MiddleClass<int> { };
+USEMEMFUNC(TopClass<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$TopClass@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN8TopClassIiE4funcEv
diff --git a/clang/test/CodeGenCXX/dllimport.cpp b/clang/test/CodeGenCXX/dllimport.cpp
index 3f3c34b..63b1192 100644
--- a/clang/test/CodeGenCXX/dllimport.cpp
+++ b/clang/test/CodeGenCXX/dllimport.cpp
@@ -662,3 +662,102 @@
USEMEMFUNC(ExplicitlySpecializedClassTemplate<void*>, f);
// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?f@?$ExplicitlySpecializedClassTemplate@PAX@@QAEXXZ"
// G32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @_ZN34ExplicitlySpecializedClassTemplateIPvE1fEv
+
+//===----------------------------------------------------------------------===//
+// Classes with template base classes
+//===----------------------------------------------------------------------===//
+
+template <typename T> struct ClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllexport) ExportedClassTemplate { void func() {} };
+template <typename T> struct __declspec(dllimport) ImportedClassTemplate { void func() {} };
+
+template <typename T> struct ExplicitlySpecializedTemplate { void func() {} };
+template <> struct ExplicitlySpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyExportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllexport) ExplicitlyExportSpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyImportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllimport) ExplicitlyImportSpecializedTemplate<int> { void func() {} };
+
+template <typename T> struct ExplicitlyInstantiatedTemplate { void func() {} };
+template struct ExplicitlyInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyExportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllexport) ExplicitlyExportInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyImportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllimport) ExplicitlyImportInstantiatedTemplate<int>;
+
+
+// MS: ClassTemplate<int> gets imported.
+struct __declspec(dllimport) DerivedFromTemplate : public ClassTemplate<int> {};
+USEMEMFUNC(ClassTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ClassTemplate@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIiE4funcEv
+
+// ImportedTemplate is explicitly imported.
+struct __declspec(dllimport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+USEMEMFUNC(ImportedClassTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ImportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: declare dllimport x86_thiscallcc void @_ZN21ImportedClassTemplateIiE4funcEv
+
+// ExportedTemplate is explicitly exported.
+struct __declspec(dllimport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+USEMEMFUNC(ExportedClassTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExportedClassTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN21ExportedClassTemplateIiE4funcEv
+
+// Base class already instantiated without attribute.
+struct DerivedFromTemplateD : public ClassTemplate<double> {};
+struct __declspec(dllimport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+USEMEMFUNC(ClassTemplate<double>, func)
+// M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?func@?$ClassTemplate@N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIdE4funcEv
+
+// MS: Base class already instantiated with dfferent attribute.
+struct __declspec(dllexport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+struct __declspec(dllimport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+USEMEMFUNC(ClassTemplate<bool>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ClassTemplate@_N@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN13ClassTemplateIbE4funcEv
+
+// Base class already specialized without dll attribute.
+struct __declspec(dllimport) DerivedFromExplicitlySpecializedTemplate : public ExplicitlySpecializedTemplate<int> {};
+USEMEMFUNC(ExplicitlySpecializedTemplate<int>, func)
+// M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?func@?$ExplicitlySpecializedTemplate@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN29ExplicitlySpecializedTemplateIiE4funcEv
+
+// Base class alredy specialized with export attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyExportSpecializedTemplate : public ExplicitlyExportSpecializedTemplate<int> {};
+USEMEMFUNC(ExplicitlyExportSpecializedTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExplicitlyExportSpecializedTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN35ExplicitlyExportSpecializedTemplateIiE4funcEv
+
+// Base class already specialized with import attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyImportSpecializedTemplate : public ExplicitlyImportSpecializedTemplate<int> {};
+USEMEMFUNC(ExplicitlyImportSpecializedTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ExplicitlyImportSpecializedTemplate@H@@QAEXXZ"
+// G32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @_ZN35ExplicitlyImportSpecializedTemplateIiE4funcEv
+
+// Base class already instantiated without dll attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyInstantiatedTemplate : public ExplicitlyInstantiatedTemplate<int> {};
+USEMEMFUNC(ExplicitlyInstantiatedTemplate<int>, func)
+// M32-DAG: define weak_odr x86_thiscallcc void @"\01?func@?$ExplicitlyInstantiatedTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr x86_thiscallcc void @_ZN30ExplicitlyInstantiatedTemplateIiE4funcEv
+
+// Base class already instantiated with export attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyExportInstantiatedTemplate : public ExplicitlyExportInstantiatedTemplate<int> {};
+USEMEMFUNC(ExplicitlyExportInstantiatedTemplate<int>, func)
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?func@?$ExplicitlyExportInstantiatedTemplate@H@@QAEXXZ"
+// G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN36ExplicitlyExportInstantiatedTemplateIiE4funcEv
+
+// Base class already instantiated with import attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyImportInstantiatedTemplate : public ExplicitlyImportInstantiatedTemplate<int> {};
+USEMEMFUNC(ExplicitlyImportInstantiatedTemplate<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$ExplicitlyImportInstantiatedTemplate@H@@QAEXXZ"
+// G32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @_ZN36ExplicitlyImportInstantiatedTemplateIiE4funcEv
+
+// MS: A dll attribute propagates through multiple levels of instantiation.
+template <typename T> struct TopClass { void func() {} };
+template <typename T> struct MiddleClass : public TopClass<T> { };
+struct __declspec(dllimport) BottomClas : public MiddleClass<int> { };
+USEMEMFUNC(TopClass<int>, func)
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?func@?$TopClass@H@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN8TopClassIiE4funcEv
diff --git a/clang/test/SemaCXX/dllexport.cpp b/clang/test/SemaCXX/dllexport.cpp
index 362e063..9a53e27 100644
--- a/clang/test/SemaCXX/dllexport.cpp
+++ b/clang/test/SemaCXX/dllexport.cpp
@@ -316,7 +316,7 @@
class __declspec(dllexport) ClassDecl;
-class __declspec(dllexport) ClassDef { };
+class __declspec(dllexport) ClassDef {};
#ifdef MS
// expected-warning@+3{{'dllexport' attribute ignored}}
@@ -328,6 +328,86 @@
template <> struct __declspec(dllexport) ExpliciallySpecializedClassTemplate<int> { void f() {} };
+//===----------------------------------------------------------------------===//
+// Classes with template base classes
+//===----------------------------------------------------------------------===//
+
+template <typename T> class ClassTemplate {};
+template <typename T> class __declspec(dllexport) ExportedClassTemplate {};
+template <typename T> class __declspec(dllimport) ImportedClassTemplate {};
+
+template <typename T> struct ExplicitlySpecializedTemplate { void func() {} };
+#ifdef MS
+// expected-note@+2{{class template 'ExplicitlySpecializedTemplate<int>' was explicitly specialized here}}
+#endif
+template <> struct ExplicitlySpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyExportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllexport) ExplicitlyExportSpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyImportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllimport) ExplicitlyImportSpecializedTemplate<int> { void func() {} };
+
+template <typename T> struct ExplicitlyInstantiatedTemplate { void func() {} };
+#ifdef MS
+// expected-note@+2{{class template 'ExplicitlyInstantiatedTemplate<int>' was instantiated here}}
+#endif
+template struct ExplicitlyInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyExportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllexport) ExplicitlyExportInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyImportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllimport) ExplicitlyImportInstantiatedTemplate<int>;
+
+// ClassTemplate<int> gets exported.
+class __declspec(dllexport) DerivedFromTemplate : public ClassTemplate<int> {};
+
+// ClassTemplate<int> is already exported.
+class __declspec(dllexport) DerivedFromTemplate2 : public ClassTemplate<int> {};
+
+// ExportedTemplate is explicitly exported.
+class __declspec(dllexport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+
+// ImportedTemplate is explicitly imported.
+class __declspec(dllexport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<double>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template without dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class DerivedFromTemplateD : public ClassTemplate<double> {};
+class __declspec(dllexport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<bool>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template with different dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class __declspec(dllimport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+class __declspec(dllexport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+
+#ifdef MS
+// expected-warning@+3{{propagating dll attribute to explicitly specialized base class template without dll attribute is unsupported}}
+// expected-note@+2{{attribute is here}}
+#endif
+struct __declspec(dllexport) DerivedFromExplicitlySpecializedTemplate : public ExplicitlySpecializedTemplate<int> {};
+
+// Base class alredy specialized with export attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyExportSpecializedTemplate : public ExplicitlyExportSpecializedTemplate<int> {};
+
+// Base class already specialized with import attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyImportSpecializedTemplate : public ExplicitlyImportSpecializedTemplate<int> {};
+
+#ifdef MS
+// expected-warning@+3{{propagating dll attribute to already instantiated base class template without dll attribute is unsupported}}
+// expected-note@+2{{attribute is here}}
+#endif
+struct __declspec(dllexport) DerivedFromExplicitlyInstantiatedTemplate : public ExplicitlyInstantiatedTemplate<int> {};
+
+// Base class already instantiated with export attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyExportInstantiatedTemplate : public ExplicitlyExportInstantiatedTemplate<int> {};
+
+// Base class already instantiated with import attribute.
+struct __declspec(dllexport) DerivedFromExplicitlyImportInstantiatedTemplate : public ExplicitlyImportInstantiatedTemplate<int> {};
+
//===----------------------------------------------------------------------===//
// Precedence
diff --git a/clang/test/SemaCXX/dllimport.cpp b/clang/test/SemaCXX/dllimport.cpp
index 8df17d7..855893c 100644
--- a/clang/test/SemaCXX/dllimport.cpp
+++ b/clang/test/SemaCXX/dllimport.cpp
@@ -955,6 +955,8 @@
class __declspec(dllimport) ClassDef { };
+template <typename T> class ClassTemplate {};
+
#ifdef MS
// expected-note@+5{{previous attribute is here}}
// expected-note@+4{{previous attribute is here}}
@@ -1000,3 +1002,84 @@
template <typename T> struct ExpliciallySpecializedClassTemplate {};
template <> struct __declspec(dllimport) ExpliciallySpecializedClassTemplate<int> { void f() {} };
+
+
+//===----------------------------------------------------------------------===//
+// Classes with template base classes
+//===----------------------------------------------------------------------===//
+
+template <typename T> class __declspec(dllexport) ExportedClassTemplate {};
+
+template <typename T> class __declspec(dllimport) ImportedClassTemplate {};
+
+// ClassTemplate<int> gets imported.
+class __declspec(dllimport) DerivedFromTemplate : public ClassTemplate<int> {};
+
+// ClassTemplate<int> is already imported.
+class __declspec(dllimport) DerivedFromTemplate2 : public ClassTemplate<int> {};
+
+// ImportedClassTemplate is expliitly imported.
+class __declspec(dllimport) DerivedFromImportedTemplate : public ImportedClassTemplate<int> {};
+
+// ExportedClassTemplate is explicitly exported.
+class __declspec(dllimport) DerivedFromExportedTemplate : public ExportedClassTemplate<int> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<double>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template without dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class DerivedFromTemplateD : public ClassTemplate<double> {};
+class __declspec(dllimport) DerivedFromTemplateD2 : public ClassTemplate<double> {};
+
+#ifdef MS
+// expected-note@+4{{class template 'ClassTemplate<bool>' was instantiated here}}
+// expected-warning@+4{{propagating dll attribute to already instantiated base class template with different dll attribute is unsupported}}
+// expected-note@+3{{attribute is here}}
+#endif
+class __declspec(dllexport) DerivedFromTemplateB : public ClassTemplate<bool> {};
+class __declspec(dllimport) DerivedFromTemplateB2 : public ClassTemplate<bool> {};
+
+template <typename T> struct ExplicitlySpecializedTemplate { void func() {} };
+#ifdef MS
+// expected-note@+2{{class template 'ExplicitlySpecializedTemplate<int>' was explicitly specialized here}}
+#endif
+template <> struct ExplicitlySpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyExportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllexport) ExplicitlyExportSpecializedTemplate<int> { void func() {} };
+template <typename T> struct ExplicitlyImportSpecializedTemplate { void func() {} };
+template <> struct __declspec(dllimport) ExplicitlyImportSpecializedTemplate<int> { void func() {} };
+
+template <typename T> struct ExplicitlyInstantiatedTemplate { void func() {} };
+#ifdef MS
+// expected-note@+2{{class template 'ExplicitlyInstantiatedTemplate<int>' was instantiated here}}
+#endif
+template struct ExplicitlyInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyExportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllexport) ExplicitlyExportInstantiatedTemplate<int>;
+template <typename T> struct ExplicitlyImportInstantiatedTemplate { void func() {} };
+template struct __declspec(dllimport) ExplicitlyImportInstantiatedTemplate<int>;
+
+#ifdef MS
+// expected-warning@+3{{propagating dll attribute to explicitly specialized base class template without dll attribute is unsupported}}
+// expected-note@+2{{attribute is here}}
+#endif
+struct __declspec(dllimport) DerivedFromExplicitlySpecializedTemplate : public ExplicitlySpecializedTemplate<int> {};
+
+// Base class already specialized with export attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyExportSpecializedTemplate : public ExplicitlyExportSpecializedTemplate<int> {};
+
+// Base class already specialized with import attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyImportSpecializedTemplate : public ExplicitlyImportSpecializedTemplate<int> {};
+
+#ifdef MS
+// expected-warning@+3{{propagating dll attribute to already instantiated base class template without dll attribute is unsupported}}
+// expected-note@+2{{attribute is here}}
+#endif
+struct __declspec(dllimport) DerivedFromExplicitlyInstantiatedTemplate : public ExplicitlyInstantiatedTemplate<int> {};
+
+// Base class already instantiated with export attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyExportInstantiatedTemplate : public ExplicitlyExportInstantiatedTemplate<int> {};
+
+// Base class already instantiated with import attribute.
+struct __declspec(dllimport) DerivedFromExplicitlyImportInstantiatedTemplate : public ExplicitlyImportInstantiatedTemplate<int> {};