2 files changed, 30 insertions, 3 deletions
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 5c3e24a0a27..be181f44069 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -2129,6 +2129,21 @@ void ASTWriter::WriteDeclContextVisibleUpdate(const DeclContext *DC) {
   Stream.EmitRecordWithBlob(UpdateVisibleAbbrev, Record, LookupTable.str());
 }
 
+/// \brief Write ADDITIONAL_TEMPLATE_SPECIALIZATIONS blocks for all templates
+/// that have new specializations in the current AST file.
+void ASTWriter::WriteAdditionalTemplateSpecializations() {
+  RecordData Record;
+  for (AdditionalTemplateSpecializationsMap::iterator
+           I = AdditionalTemplateSpecializations.begin(),
+           E = AdditionalTemplateSpecializations.end();
+       I != E; ++I) {
+    Record.clear();
+    Record.push_back(I->first);
+    Record.insert(Record.end(), I->second.begin(), I->second.end());
+    Stream.EmitRecord(ADDITIONAL_TEMPLATE_SPECIALIZATIONS, Record);
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // General Serialization Routines
 //===----------------------------------------------------------------------===//
@@ -2638,6 +2653,10 @@ void ASTWriter::WriteASTChain(Sema &SemaRef, MemorizeStatCalls *StatCalls,
          I != E; ++I)
     WriteDeclContextVisibleUpdate(*I);
 
+  // Write the updates to C++ template specialization lists.
+  if (!AdditionalTemplateSpecializations.empty())
+    WriteAdditionalTemplateSpecializations();
+
   Record.clear();
   Record.push_back(NumStatements);
   Record.push_back(NumMacros);
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index 3edb6302f8f..413f544f4c1 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -888,13 +888,21 @@ void ASTDeclWriter::VisitClassTemplateSpecializationDecl(
   llvm::PointerUnion<ClassTemplateDecl *,
                      ClassTemplatePartialSpecializationDecl *> InstFrom
     = D->getSpecializedTemplateOrPartial();
+  Decl *InstFromD;
   if (InstFrom.is<ClassTemplateDecl *>()) {
-    Writer.AddDeclRef(InstFrom.get<ClassTemplateDecl *>(), Record);
+    InstFromD = InstFrom.get<ClassTemplateDecl *>();
+    Writer.AddDeclRef(InstFromD, Record);
   } else {
-    Writer.AddDeclRef(InstFrom.get<ClassTemplatePartialSpecializationDecl *>(),
-                      Record);
+    InstFromD = InstFrom.get<ClassTemplatePartialSpecializationDecl *>();
+    Writer.AddDeclRef(InstFromD, Record);
     Writer.AddTemplateArgumentList(&D->getTemplateInstantiationArgs(), Record);
+    InstFromD = cast<ClassTemplatePartialSpecializationDecl>(InstFromD)->
+                    getSpecializedTemplate();
   }
+  // Is this a specialization of an already-serialized template?
+  if (InstFromD->getCanonicalDecl()->getPCHLevel() != 0)
+    Writer.AddAdditionalTemplateSpecialization(Writer.getDeclID(InstFromD),
+                                               Writer.getDeclID(D));
 
   // Explicit info.
   Writer.AddTypeSourceInfo(D->getTypeAsWritten(), Record);