From 3b3f2f613e907670a1245e740a582ef011395059 Mon Sep 17 00:00:00 2001
From: Shoaib Meenai <smeenai@fb.com>
Date: Wed, 9 Nov 2016 23:52:20 +0000
Subject: [PATCH] [Sema] Use MS ABI behavior for dllexport in Itanium

Similar to r284288, make the Itanium ABI follow MS ABI dllexport
semantics in the case of an explicit instantiation declaration followed
by a dllexport explicit instantiation definition.

Differential Revision: https://reviews.llvm.org/D26471

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@286419 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaTemplate.cpp                     |  3 ++-
 test/CodeGenCXX/windows-itanium-dllexport.cpp | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index ce41a5eb74..e87fc73c69 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -7674,7 +7674,8 @@ Sema::ActOnExplicitInstantiation(Scope *S,
       Def->setTemplateSpecializationKind(TSK);
 
       if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
-          Context.getTargetInfo().getCXXABI().isMicrosoft()) {
+          (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
+           Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
         // In the MS ABI, an explicit instantiation definition can add a dll
         // attribute to a template with a previous instantiation declaration.
         // MinGW doesn't allow this.
diff --git a/test/CodeGenCXX/windows-itanium-dllexport.cpp b/test/CodeGenCXX/windows-itanium-dllexport.cpp
index 934c6a2961..2b9b783e03 100644
--- a/test/CodeGenCXX/windows-itanium-dllexport.cpp
+++ b/test/CodeGenCXX/windows-itanium-dllexport.cpp
@@ -7,3 +7,19 @@ struct __declspec(dllexport) s {
 // CHECK: define {{.*}} dllexport {{.*}} @_ZN1saSERKS_
 // CHECK: define {{.*}} dllexport {{.*}} @_ZN1s1fEv
 
+template <class T>
+class c {
+  void f() {}
+};
+
+template class __declspec(dllexport) c<int>;
+
+// CHECK: define {{.*}} dllexport {{.*}} @_ZN1cIiEaSERKS0_
+// CHECK: define {{.*}} dllexport {{.*}} @_ZN1cIiE1fEv
+
+extern template class c<char>;
+template class __declspec(dllexport) c<char>;
+
+// CHECK: define {{.*}} dllexport {{.*}} @_ZN1cIcEaSERKS0_
+// CHECK: define {{.*}} dllexport {{.*}} @_ZN1cIcE1fEv
+
-- 
2.40.0