[PCH/preamble] Make sure that if the preamble/PCH was serialized with errors that we set diagnostic engine state appropriately.

Otherwise there can be a crash with CFG analysis warnings doing work on invalid AST.

Fixes crash of rdar://26224134

llvm-svn: 275313

1 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/Serialization/GeneratePCH.cpp b/clang/lib/Serialization/GeneratePCH.cpp
index 4a2255a..308fde8 100644
--- a/clang/lib/Serialization/GeneratePCH.cpp
+++ b/clang/lib/Serialization/GeneratePCH.cpp
@@ -51,7 +51,10 @@ void PCHGenerator::HandleTranslationUnit(ASTContext &Ctx) {
   // Emit the PCH file to the Buffer.
   assert(SemaPtr && "No Sema?");
   Buffer->Signature =
-      Writer.WriteAST(*SemaPtr, OutputFile, Module, isysroot, hasErrors);
+      Writer.WriteAST(*SemaPtr, OutputFile, Module, isysroot,
+                      // For serialization we are lenient if the errors were
+                      // only warn-as-error kind.
+                      PP.getDiagnostics().hasUncompilableErrorOccurred());
 
   Buffer->IsComplete = true;
 }