A little hack to identify unwanted concurrency in CIndex

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@97831 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index ef14df1..4ea1ccc 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -36,9 +36,12 @@
 using namespace clang;
 
 ASTUnit::ASTUnit(bool _MainFileIsAST)
-  : MainFileIsAST(_MainFileIsAST) {
+  : MainFileIsAST(_MainFileIsAST), ConcurrencyCheckValue(CheckUnlocked) {
 }
 ASTUnit::~ASTUnit() {
+#ifndef NDEBUG
+  ConcurrencyCheckValue = CheckLocked;
+#endif
   for (unsigned I = 0, N = TemporaryFiles.size(); I != N; ++I)
     TemporaryFiles[I].eraseFromDisk();
 }