Update clang to r339409b.

Change-Id: Ied8a188bb072c40035320acedc86164b66d920af
diff --git a/linux-x64/clang/include/llvm/XRay/FileHeaderReader.h b/linux-x64/clang/include/llvm/XRay/FileHeaderReader.h
new file mode 100644
index 0000000..3b8809b
--- /dev/null
+++ b/linux-x64/clang/include/llvm/XRay/FileHeaderReader.h
@@ -0,0 +1,33 @@
+//===- FileHeaderReader.h - XRay Trace File Header Reading Function -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares functions that can load an XRay log header from various
+// sources.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_LIB_XRAY_FILEHEADERREADER_H_
+#define LLVM_LIB_XRAY_FILEHEADERREADER_H_
+
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Error.h"
+#include "llvm/XRay/XRayRecord.h"
+#include <cstdint>
+
+namespace llvm {
+namespace xray {
+
+/// Convenience function for loading the file header given a data extractor at a
+/// specified offset.
+Expected<XRayFileHeader> readBinaryFormatHeader(DataExtractor &HeaderExtractor,
+                                                uint32_t &OffsetPtr);
+
+} // namespace xray
+} // namespace llvm
+
+#endif // LLVM_LIB_XRAY_FILEHEADERREADER_H_