diff --git a/lib/Interpreter/CIFactory.cpp b/lib/Interpreter/CIFactory.cpp
index 7490b68f..90f8c99d 100644
--- a/lib/Interpreter/CIFactory.cpp
+++ b/lib/Interpreter/CIFactory.cpp
@@ -731,7 +731,7 @@ namespace {
     const SrcMgr::ContentCache* MainFileCC
       = MainFileSLocE.getFile().getContentCache();
     if (!Buffer)
-      Buffer = llvm::MemoryBuffer::getMemBuffer("/*CLING DEFAULT MEMBUF*/\n");
+      Buffer = llvm::MemoryBuffer::getMemBuffer("/*CLING DEFAULT MEMBUF*/;\n");
     const_cast<SrcMgr::ContentCache*>(MainFileCC)->setBuffer(std::move(Buffer));
 
     // Set up the preprocessor
diff --git a/lib/Interpreter/IncrementalParser.cpp b/lib/Interpreter/IncrementalParser.cpp
index 3679ded2..5d2e5be9 100644
--- a/lib/Interpreter/IncrementalParser.cpp
+++ b/lib/Interpreter/IncrementalParser.cpp
@@ -177,6 +177,11 @@ namespace cling {
     if (External)
       External->StartTranslationUnit(m_Consumer);
 
+    Parser::DeclGroupPtrTy ADecl;
+    // Start parsing the "main file" to warm up lexing (enter caching lex mode
+    // for ParseInternal()'s call EnterSourceFile() to make sense.
+    while (!m_Parser->ParseTopLevelDecl(ADecl)) {}
+
     // If I belong to the parent Interpreter, only then do
     // the #include <new>
     if (!isChildInterpreter && m_CI->getLangOpts().CPlusPlus) {