1 files changed, 17 insertions, 11 deletions
diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index d660638a1e8a..01f7ca8aba9b 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -1036,8 +1036,6 @@ static void checkAndSanitizeDiags(SmallVectorImpl<StoredDiagnostic> &
 bool ASTUnit::Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
                     std::unique_ptr<llvm::MemoryBuffer> OverrideMainBuffer,
                     IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
-  SavedMainFileBuffer.reset();
-
   if (!Invocation)
     return true;
 
@@ -1090,17 +1088,11 @@ bool ASTUnit::Parse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
     Clang->createFileManager();
     FileMgr = &Clang->getFileManager();
   }
-  SourceMgr = new SourceManager(getDiagnostics(), *FileMgr,
-                                UserFilesAreVolatile);
-  TheSema.reset();
-  Ctx = nullptr;
-  PP = nullptr;
-  Reader = nullptr;
 
-  // Clear out old caches and data.
-  TopLevelDecls.clear();
-  clearFileLevelDecls();
+  ResetForParse();
 
+  SourceMgr = new SourceManager(getDiagnostics(), *FileMgr,
+                                UserFilesAreVolatile);
   if (!OverrideMainBuffer) {
     checkAndRemoveNonDriverDiags(StoredDiagnostics);
     TopLevelDeclsInPreamble.clear();
@@ -1999,6 +1991,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
   PreprocessorOptions &PPOpts = CI->getPreprocessorOpts();
   PPOpts.RemappedFilesKeepOriginalName = RemappedFilesKeepOriginalName;
   PPOpts.AllowPCHWithCompilerErrors = AllowPCHWithCompilerErrors;
+  PPOpts.GeneratePreamble = PrecompilePreambleAfterNParses != 0;
   
   // Override the resources path.
   CI->getHeaderSearchOpts().ResourceDir = ResourceFilesPath;
@@ -2115,6 +2108,19 @@ bool ASTUnit::Reparse(std::shared_ptr<PCHContainerOperations> PCHContainerOps,
   return Result;
 }
 
+void ASTUnit::ResetForParse() {
+  SavedMainFileBuffer.reset();
+
+  SourceMgr.reset();
+  TheSema.reset();
+  Ctx.reset();
+  PP.reset();
+  Reader.reset();
+
+  TopLevelDecls.clear();
+  clearFileLevelDecls();
+}
+
 //----------------------------------------------------------------------------//
 // Code completion
 //----------------------------------------------------------------------------//