From e124612eda3561d10fa5749583e0fabf813e2c82 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Fri, 3 Nov 2017 01:26:01 +0000
Subject: [PATCH] [c++17] Visit class template explicit specializations just
 like all other class definitions in codegen.

If an explicit specialization has a static data member, it may be a definition and we may need to register it for emission.

llvm-svn: 317296
---
 clang/lib/CodeGen/CodeGenModule.cpp              | 16 +++++++---------
 clang/test/CodeGenCXX/cxx1z-inline-variables.cpp | 12 ++++++++++++
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index b2a18a0..b155017 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4030,6 +4030,13 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
   case Decl::Namespace:
     EmitDeclContext(cast<NamespaceDecl>(D));
     break;
+  case Decl::ClassTemplateSpecialization: {
+    const auto *Spec = cast<ClassTemplateSpecializationDecl>(D);
+    if (DebugInfo &&
+        Spec->getSpecializationKind() == TSK_ExplicitInstantiationDefinition &&
+        Spec->hasDefinition())
+      DebugInfo->completeTemplateDefinition(*Spec);
+  } LLVM_FALLTHROUGH;
   case Decl::CXXRecord:
     if (DebugInfo) {
       if (auto *ES = D->getASTContext().getExternalSource())
@@ -4216,15 +4223,6 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
     EmitOMPThreadPrivateDecl(cast<OMPThreadPrivateDecl>(D));
     break;
 
-  case Decl::ClassTemplateSpecialization: {
-    const auto *Spec = cast<ClassTemplateSpecializationDecl>(D);
-    if (DebugInfo &&
-        Spec->getSpecializationKind() == TSK_ExplicitInstantiationDefinition &&
-        Spec->hasDefinition())
-      DebugInfo->completeTemplateDefinition(*Spec);
-    break;
-  }
-
   case Decl::OMPDeclareReduction:
     EmitOMPDeclareReduction(cast<OMPDeclareReductionDecl>(D));
     break;
diff --git a/clang/test/CodeGenCXX/cxx1z-inline-variables.cpp b/clang/test/CodeGenCXX/cxx1z-inline-variables.cpp
index 0d2ec92..2d16acd 100644
--- a/clang/test/CodeGenCXX/cxx1z-inline-variables.cpp
+++ b/clang/test/CodeGenCXX/cxx1z-inline-variables.cpp
@@ -67,6 +67,18 @@ int &use3 = X<int>::a;
 template<> int X<int>::b = 20;
 template<> inline int X<int>::c = 30;
 
+template<typename T> struct Y;
+template<> struct Y<int> {
+  static constexpr int a = 123;
+  static constexpr int b = 456;
+  static constexpr int c = 789;
+};
+// CHECK: @_ZN1YIiE1aE = weak_odr constant i32 123
+constexpr int Y<int>::a;
+// CHECK: @_ZN1YIiE1bE = linkonce_odr constant i32 456
+const int &yib = Y<int>::b;
+// CHECK-NOT: @_ZN1YIiE1cE
+
 // CHECK-LABEL: define {{.*}}global_var_init
 // CHECK: call i32 @_Z1fv
 
-- 
2.7.4