[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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@275313 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/Frontend/ChainedIncludesSource.cpp b/lib/Frontend/ChainedIncludesSource.cpp
index 1c1081fbe0..51771bfb54 100644
--- a/lib/Frontend/ChainedIncludesSource.cpp
+++ b/lib/Frontend/ChainedIncludesSource.cpp
@@ -164,7 +164,7 @@ IntrusiveRefCntPtr<ExternalSemaSource> clang::createChainedIncludesSource(
     ArrayRef<llvm::IntrusiveRefCntPtr<ModuleFileExtension>> Extensions;
     auto consumer = llvm::make_unique<PCHGenerator>(
         Clang->getPreprocessor(), "-", nullptr, /*isysroot=*/"", Buffer,
-        Extensions);
+        Extensions, /*AllowASTWithErrors=*/true);
     Clang->getASTContext().setASTMutationListener(
                                             consumer->GetASTMutationListener());
     Clang->setASTConsumer(std::move(consumer));