diff --git a/lib/Frontend/CompilerInstance.cpp b/lib/Frontend/CompilerInstance.cpp
index cab6b90..803e418 100644
--- a/lib/Frontend/CompilerInstance.cpp
+++ b/lib/Frontend/CompilerInstance.cpp
@@ -651,6 +651,10 @@
   // created. This complexity should be lifted elsewhere.
   getTarget().setForcedLangOptions(getLangOpts());
 
+  // rewriter project will change target built-in bool type from its default. 
+  if (getFrontendOpts().ProgramAction == frontend::RewriteObjC)
+    getTarget().noSignedCharForObjCBool();
+
   // Validate/process some options.
   if (getHeaderSearchOpts().Verbose)
     OS << "clang -cc1 version " CLANG_VERSION_STRING