3 files changed, 18 insertions, 2 deletions
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 05987be8455..818b51543d3 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1820,6 +1820,10 @@ static bool shouldOmitDefinition(codegenoptions::DebugInfoKind DebugKind,
   if (DebugTypeExtRefs && isDefinedInClangModule(RD->getDefinition()))
     return true;
 
+  if (auto *ES = RD->getASTContext().getExternalSource())
+    if (ES->hasExternalDefinitions(RD) == ExternalASTSource::EK_Always)
+      return true;
+
   if (DebugKind > codegenoptions::LimitedDebugInfo)
     return false;
 
@@ -2552,11 +2556,17 @@ void CGDebugInfo::completeTemplateDefinition(
     const ClassTemplateSpecializationDecl &SD) {
   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
     return;
+  completeUnusedClass(SD);
+}
+
+void CGDebugInfo::completeUnusedClass(const CXXRecordDecl &D) {
+  if (DebugKind <= codegenoptions::DebugLineTablesOnly)
+    return;
 
-  completeClassData(&SD);
+  completeClassData(&D);
   // In case this type has no member function definitions being emitted, ensure
   // it is retained
-  RetainedTypes.push_back(CGM.getContext().getRecordType(&SD).getAsOpaquePtr());
+  RetainedTypes.push_back(CGM.getContext().getRecordType(&D).getAsOpaquePtr());
 }
 
 llvm::DIType *CGDebugInfo::getOrCreateType(QualType Ty, llvm::DIFile *Unit) {
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index c6d1c66e131..5050ca0ad3f 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -438,6 +438,7 @@ public:
   void completeClass(const RecordDecl *RD);
 
   void completeTemplateDefinition(const ClassTemplateSpecializationDecl &SD);
+  void completeUnusedClass(const CXXRecordDecl &D);
 
   /// Create debug info for a macro defined by a #define directive or a macro
   /// undefined by a #undef directive.
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 96358bf6119..7fe8bf04129 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3820,6 +3820,11 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
     EmitDeclContext(cast<NamespaceDecl>(D));
     break;
   case Decl::CXXRecord:
+    if (DebugInfo) {
+      if (auto *ES = D->getASTContext().getExternalSource())
+        if (ES->hasExternalDefinitions(D) == ExternalASTSource::EK_Never)
+          DebugInfo->completeUnusedClass(cast<CXXRecordDecl>(*D));
+    }
     // Emit any static data members, they may be definitions.
     for (auto *I : cast<CXXRecordDecl>(D)->decls())
       if (isa<VarDecl>(I) || isa<CXXRecordDecl>(I))