Move Preprocessor over to std::shared_ptr rather than IntrusiveRefCntPtr

llvm-svn: 291166
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index e871b31..39fc137 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -224,7 +224,7 @@
     // file, otherwise the CompilerInstance will happily destroy them.
     CI.setFileManager(&AST->getFileManager());
     CI.setSourceManager(&AST->getSourceManager());
-    CI.setPreprocessor(&AST->getPreprocessor());
+    CI.setPreprocessor(AST->getPreprocessorPtr());
     CI.setASTContext(&AST->getASTContext());
 
     setCurrentInput(Input, std::move(AST));