1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index dce8c1efda23..3596337c245e 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -150,6 +150,9 @@ Preprocessor::Preprocessor(std::shared_ptr<PreprocessorOptions> PPOpts,
     Ident_GetExceptionInfo = Ident_GetExceptionCode = nullptr;
     Ident_AbnormalTermination = nullptr;
   }
+
+  if (this->PPOpts->GeneratePreamble)
+    PreambleConditionalStack.startRecording();
 }
 
 Preprocessor::~Preprocessor() {
@@ -532,6 +535,12 @@ void Preprocessor::EnterMainSourceFile() {
 
   // Start parsing the predefines.
   EnterSourceFile(FID, nullptr, SourceLocation());
+
+  // Restore the conditional stack from the preamble, if there is one.
+  if (PreambleConditionalStack.isReplaying()) {
+    CurPPLexer->setConditionalLevels(PreambleConditionalStack.getStack());
+    PreambleConditionalStack.doneReplaying();
+  }
 }
 
 void Preprocessor::EndSourceFile() {