3 files changed, 14 insertions, 3 deletions
diff --git a/lib/AST/RecordLayoutBuilder.cpp b/lib/AST/RecordLayoutBuilder.cpp
index c5465a5dca..9444be301b 100644
--- a/lib/AST/RecordLayoutBuilder.cpp
+++ b/lib/AST/RecordLayoutBuilder.cpp
@@ -1712,9 +1712,6 @@ const CXXMethodDecl *ASTContext::getKeyFunction(const CXXRecordDecl *RD) {
   const CXXMethodDecl *&Entry = KeyFunctions[RD];
   if (!Entry)
     Entry = RecordLayoutBuilder::ComputeKeyFunction(RD);
-  else
-    assert(Entry == RecordLayoutBuilder::ComputeKeyFunction(RD) &&
-           "Key function changed!");
 
   return Entry;
 }
diff --git a/lib/Serialization/ASTReaderDecl.cpp b/lib/Serialization/ASTReaderDecl.cpp
index 97adbf73cc..e8fe264651 100644
--- a/lib/Serialization/ASTReaderDecl.cpp
+++ b/lib/Serialization/ASTReaderDecl.cpp
@@ -833,6 +833,15 @@ void ASTDeclReader::VisitCXXRecordDecl(CXXRecordDecl *D) {
     break;
   }
   }
+
+  // Load the key function to avoid deserializing every method so we can
+  // compute it.
+  if (D->IsDefinition) {
+    CXXMethodDecl *Key
+        = cast_or_null<CXXMethodDecl>(Reader.GetDecl(Record[Idx++]));
+    if (Key)
+      C.KeyFunctions[D] = Key;
+  }
 }
 
 void ASTDeclReader::VisitCXXMethodDecl(CXXMethodDecl *D) {
diff --git a/lib/Serialization/ASTWriterDecl.cpp b/lib/Serialization/ASTWriterDecl.cpp
index 3e1ba89a66..9aaaa485b6 100644
--- a/lib/Serialization/ASTWriterDecl.cpp
+++ b/lib/Serialization/ASTWriterDecl.cpp
@@ -770,6 +770,11 @@ void ASTDeclWriter::VisitCXXRecordDecl(CXXRecordDecl *D) {
     Record.push_back(CXXRecNotTemplate);
   }
 
+  // Store the key function to avoid deserializing every method so we can
+  // compute it.
+  if (D->IsDefinition)
+    Writer.AddDeclRef(Context.getKeyFunction(D), Record);
+
   Code = serialization::DECL_CXX_RECORD;
 }