Merging r367661:

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r367661 | hans | 2019-08-02 09:51:41 +0200 (Fri, 02 Aug 2019) | 5 lines

Don't try emitting dllexported explicitly defaulted non-trivial ctors twice during explicit template instantiation definition (PR42857)

Trying to emit the definition twice triggers an assert.

Differential revision: https://reviews.llvm.org/D65579
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_90@367805 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 1 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 3d4c7fc3e0..2ffb0b4892 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -11425,7 +11425,13 @@ void Sema::ActOnFinishCXXNonNestedClass(Decl *D) {
     std::swap(DelayedDllExportMemberFunctions, WorkList);
     for (CXXMethodDecl *M : WorkList) {
       DefineImplicitSpecialMember(*this, M, M->getLocation());
-      ActOnFinishInlineFunctionDef(M);
+
+      // Pass the method to the consumer to get emitted. This is not necessary
+      // for explicit instantiation definitions, as they will get emitted
+      // anyway.
+      if (M->getParent()->getTemplateSpecializationKind() !=
+          TSK_ExplicitInstantiationDefinition)
+        ActOnFinishInlineFunctionDef(M);
     }
   }
 }
diff --git a/test/CodeGenCXX/dllexport.cpp b/test/CodeGenCXX/dllexport.cpp
index 5d4523f2ea..59ba6d8548 100644
--- a/test/CodeGenCXX/dllexport.cpp
+++ b/test/CodeGenCXX/dllexport.cpp
@@ -860,6 +860,13 @@ struct PR40006 {
 };
 // M32-DAG: define weak_odr dso_local dllexport x86_thiscallcc %"struct.InClassInits::PR40006"* @"??0PR40006@InClassInits@@QAE@XZ"
 
+// PR42857: Clang would try to emit the non-trivial explicitly defaulted
+// dllexport ctor twice when doing an explicit instantiation definition.
+struct Qux { Qux(); };
+template <typename T> struct PR42857 { __declspec(dllexport) PR42857() = default; Qux q; };
+template struct PR42857<int>;
+// M32-DAG: define weak_odr dso_local dllexport x86_thiscallcc %"struct.InClassInits::PR42857"* @"??0?$PR42857@H@InClassInits@@QAE@XZ"
+
 }
 
 // We had an issue where instantiating A would force emission of B's delayed