1 files changed, 2 insertions, 1 deletions
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index ef14df10345e..63cf98d3da5d 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -36,9 +36,10 @@
 using namespace clang;
 
 ASTUnit::ASTUnit(bool _MainFileIsAST)
-  : MainFileIsAST(_MainFileIsAST) {
+  : MainFileIsAST(_MainFileIsAST), ConcurrencyCheckValue(CheckUnlocked) {
 }
 ASTUnit::~ASTUnit() {
+  ConcurrencyCheckValue = CheckLocked;
   for (unsigned I = 0, N = TemporaryFiles.size(); I != N; ++I)
     TemporaryFiles[I].eraseFromDisk();
 }