[PCH] Write out the ClassTemplateDecl::Common::InjectedClassNameType type

reference instead of relying on computing it.

In general, if storage is no issue, it is preferable to deserialize info from
the PCH instead of trying to recompute it after the PCH was loaded.

The incentive to change this now was due to r155303 changing how friend template
classes in dependent contexts are handled; such classes can now be chained to
a previous template class but the computed InjectedClassNameType may be different
due to the extra template parameters from the dependent context.

The new handling requires more investigation but, in the meantime, writing out
InjectedClassNameType fixes PCH issue in rdar://12627738.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@167425 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 49 insertions, 3 deletions

diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 17509c8527..c42944df63 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -1353,10 +1353,10 @@ void ASTDeclReader::VisitClassTemplateDecl(ClassTemplateDecl *D) {
     for (unsigned I = 0; I != Size; ++I)
       SpecIDs.push_back(ReadDeclID(Record, Idx));
 
+    ClassTemplateDecl::Common *CommonPtr = D->getCommonPtr();
     if (SpecIDs[0]) {
       typedef serialization::DeclID DeclID;
       
-      ClassTemplateDecl::Common *CommonPtr = D->getCommonPtr();
       // FIXME: Append specializations!
       CommonPtr->LazySpecializations
         = new (Reader.getContext()) DeclID [SpecIDs.size()];
@@ -1364,7 +1364,7 @@ void ASTDeclReader::VisitClassTemplateDecl(ClassTemplateDecl *D) {
              SpecIDs.size() * sizeof(DeclID));
     }
     
-    // InjectedClassNameType is computed.
+    CommonPtr->InjectedClassNameType = Reader.readType(F, Record, Idx);
   }
 }
 
diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index e84afba549..7486565763 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -1084,7 +1084,7 @@ void ASTDeclWriter::VisitClassTemplateDecl(ClassTemplateDecl *D) {
       Writer.AddDeclRef(&*I, Record); 
     }
 
-    // InjectedClassNameType is computed, no need to write it.
+    Writer.AddTypeRef(D->getCommonPtr()->InjectedClassNameType, Record);
   }
   Code = serialization::DECL_CLASS_TEMPLATE;
 }
diff --git a/test/PCH/friend-template.cpp b/test/PCH/friend-template.cpp
new file mode 100644
index 0000000000..989819b64f
--- /dev/null
+++ b/test/PCH/friend-template.cpp
@@ -0,0 +1,46 @@
+// Test this without pch.
+// RUN: %clang_cc1 -include %s -fsyntax-only -verify %s
+
+// Test with pch.
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fsyntax-only -verify %s 
+
+// expected-no-diagnostics
+
+#ifndef HEADER
+#define HEADER
+
+// rdar://12627738
+namespace rdar12627738 {
+
+class RecyclerTag {
+    template <typename T> friend class Recycler;
+};
+
+}
+
+#else
+
+namespace rdar12627738 {
+
+template<typename TTag>
+class CRN {
+    template <typename T> friend class Recycler;
+};
+
+
+template<typename T>
+class Recycler {
+public:
+    Recycler ();
+};
+
+
+template<typename T>
+Recycler<T>::Recycler ()
+{
+}
+
+}
+
+#endif