diff --git a/lib/Debugger/SourceFile.cpp b/lib/Debugger/SourceFile.cpp
index 8e40c8815d2..23144d9ea5d 100644
--- a/lib/Debugger/SourceFile.cpp
+++ b/lib/Debugger/SourceFile.cpp
@@ -12,6 +12,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Debugger/SourceFile.h"
+#include <cassert>
+
 using namespace llvm;
 
 /// readFile - Load Filename