diff --git a/lib/Frontend/FrontendAction.cpp b/lib/Frontend/FrontendAction.cpp
index 60e6156..075fe93 100644
--- a/lib/Frontend/FrontendAction.cpp
+++ b/lib/Frontend/FrontendAction.cpp
@@ -455,6 +455,8 @@
 
 void ASTFrontendAction::ExecuteAction() {
   CompilerInstance &CI = getCompilerInstance();
+  if (!CI.hasPreprocessor())
+    return;
 
   // FIXME: Move the truncation aspect of this into Sema, we delayed this till
   // here so the source manager would be initialized.