Update clang to r339409b.

Change-Id: Ied8a188bb072c40035320acedc86164b66d920af
diff --git a/linux-x64/clang/include/llvm/XRay/BlockVerifier.h b/linux-x64/clang/include/llvm/XRay/BlockVerifier.h
new file mode 100644
index 0000000..b43a435
--- /dev/null
+++ b/linux-x64/clang/include/llvm/XRay/BlockVerifier.h
@@ -0,0 +1,69 @@
+//===- BlockVerifier.h - FDR Block Verifier -------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// An implementation of the RecordVisitor which verifies a sequence of records
+// associated with a block, following the FDR mode log format's specifications.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_INCLUDE_LLVM_XRAY_BLOCKVERIFIER_H_
+#define LLVM_INCLUDE_LLVM_XRAY_BLOCKVERIFIER_H_
+
+#include "llvm/XRay/FDRRecords.h"
+#include <array>
+#include <bitset>
+
+namespace llvm {
+namespace xray {
+
+class BlockVerifier : public RecordVisitor {
+public:
+  // We force State elements to be size_t, to be used as indices for containers.
+  enum class State : std::size_t {
+    Unknown,
+    BufferExtents,
+    NewBuffer,
+    WallClockTime,
+    PIDEntry,
+    NewCPUId,
+    TSCWrap,
+    CustomEvent,
+    Function,
+    CallArg,
+    EndOfBuffer,
+    StateMax,
+  };
+
+private:
+  // We keep track of the current record seen by the verifier.
+  State CurrentRecord = State::Unknown;
+
+  // Transitions the current record to the new record, records an error on
+  // invalid transitions.
+  Error transition(State To);
+
+public:
+  Error visit(BufferExtents &) override;
+  Error visit(WallclockRecord &) override;
+  Error visit(NewCPUIDRecord &) override;
+  Error visit(TSCWrapRecord &) override;
+  Error visit(CustomEventRecord &) override;
+  Error visit(CallArgRecord &) override;
+  Error visit(PIDRecord &) override;
+  Error visit(NewBufferRecord &) override;
+  Error visit(EndBufferRecord &) override;
+  Error visit(FunctionRecord &) override;
+
+  Error verify();
+  void reset();
+};
+
+} // namespace xray
+} // namespace llvm
+
+#endif // LLVM_INCLUDE_LLVM_XRAY_BLOCKVERIFIER_H_