From 5148a692554b5680815a40fa8c03a2a62689b3de Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans@hanshq.net>
Date: Sat, 23 Aug 2014 22:34:43 +0000
Subject: [PATCH] MS ABI: Inherit DLL attributes to partial class template
 specializations

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216333 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaDeclCXX.cpp      | 13 +++++++++++++
 test/CodeGenCXX/dllexport.cpp |  8 ++++++++
 test/CodeGenCXX/dllimport.cpp |  9 +++++++++
 3 files changed, 30 insertions(+)

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 844011880e..5e789fe20e 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -4421,6 +4421,19 @@ static void CheckAbstractClassUsage(AbstractUsageInfo &Info,
 /// \brief Check class-level dllimport/dllexport attribute.
 static void checkDLLAttribute(Sema &S, CXXRecordDecl *Class) {
   Attr *ClassAttr = getDLLAttr(Class);
+
+  // MSVC inherits DLL attributes to partial class template specializations.
+  if (S.Context.getTargetInfo().getCXXABI().isMicrosoft() && !ClassAttr) {
+    if (auto *Spec = dyn_cast<ClassTemplatePartialSpecializationDecl>(Class)) {
+      if (Attr *TemplateAttr =
+              getDLLAttr(Spec->getSpecializedTemplate()->getTemplatedDecl())) {
+        auto *A = cast<InheritableAttr>(TemplateAttr->clone(S.getASTContext()));
+        A->setInherited(true);
+        ClassAttr = A;
+      }
+    }
+  }
+
   if (!ClassAttr)
     return;
 
diff --git a/test/CodeGenCXX/dllexport.cpp b/test/CodeGenCXX/dllexport.cpp
index 4cf6005134..44af5d0215 100644
--- a/test/CodeGenCXX/dllexport.cpp
+++ b/test/CodeGenCXX/dllexport.cpp
@@ -579,12 +579,20 @@ USEMEMFUNC(PartiallySpecializedClassTemplate<void*>, f);
 // M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?f@?$PartiallySpecializedClassTemplate@PAX@@QAEXXZ"
 // G32-DAG: define weak_odr dllexport x86_thiscallcc void @_ZN33PartiallySpecializedClassTemplateIPvE1fEv
 
+// Attributes on explicit specializations are honored.
 template <typename T> struct ExplicitlySpecializedClassTemplate {};
 template <> struct __declspec(dllexport) ExplicitlySpecializedClassTemplate<void*> { void f() {} };
 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
 
+// MS inherits DLL attributes to partial specializations.
+template <typename T> struct __declspec(dllexport) PartiallySpecializedExportedClassTemplate {};
+template <typename T> struct PartiallySpecializedExportedClassTemplate<T*> { void f() {} };
+USEMEMFUNC(PartiallySpecializedExportedClassTemplate<void*>, f);
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01?f@?$PartiallySpecializedExportedClassTemplate@PAX@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc @_ZN41PartiallySpecializedExportedClassTemplateIPvE1fEv
+
 //===----------------------------------------------------------------------===//
 // Classes with template base classes
 //===----------------------------------------------------------------------===//
diff --git a/test/CodeGenCXX/dllimport.cpp b/test/CodeGenCXX/dllimport.cpp
index c0949942dc..3292a9fa38 100644
--- a/test/CodeGenCXX/dllimport.cpp
+++ b/test/CodeGenCXX/dllimport.cpp
@@ -679,12 +679,21 @@ USEMEMFUNC(PartiallySpecializedClassTemplate<void*>, f);
 // M32-DAG: define linkonce_odr x86_thiscallcc void @"\01?f@?$PartiallySpecializedClassTemplate@PAX@@QAEXXZ"
 // G32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @_ZN33PartiallySpecializedClassTemplateIPvE1fEv
 
+// Attributes on explicit specializations are honored.
 template <typename T> struct ExplicitlySpecializedClassTemplate {};
 template <> struct __declspec(dllimport) ExplicitlySpecializedClassTemplate<void*> { void f() {} };
 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
 
+// MS inherits DLL attributes to partial specializations.
+template <typename T> struct __declspec(dllimport) PartiallySpecializedImportedClassTemplate {};
+template <typename T> struct PartiallySpecializedImportedClassTemplate<T*> { void f() {} };
+USEMEMFUNC(PartiallySpecializedImportedClassTemplate<void*>, f);
+// M32-DAG: {{declare|define available_externally}} dllimport x86_thiscallcc void @"\01?f@?$PartiallySpecializedImportedClassTemplate@PAX@@QAEXXZ"
+// G32-DAG: define linkonce_odr x86_thiscallcc void @_ZN41PartiallySpecializedImportedClassTemplateIPvE1fEv
+
+
 //===----------------------------------------------------------------------===//
 // Classes with template base classes
 //===----------------------------------------------------------------------===//
-- 
2.40.0