Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/Support/CodeGenCoverage.h b/linux-x64/clang/include/llvm/Support/CodeGenCoverage.h
index d5bd837..c863be3 100644
--- a/linux-x64/clang/include/llvm/Support/CodeGenCoverage.h
+++ b/linux-x64/clang/include/llvm/Support/CodeGenCoverage.h
@@ -23,15 +23,18 @@
   BitVector RuleCoverage;
 
 public:
+  using const_covered_iterator = BitVector::const_set_bits_iterator;
+
   CodeGenCoverage();
 
   void setCovered(uint64_t RuleID);
-  bool isCovered(uint64_t RuleID);
+  bool isCovered(uint64_t RuleID) const;
+  iterator_range<const_covered_iterator> covered() const;
 
   bool parse(MemoryBuffer &Buffer, StringRef BackendName);
   bool emit(StringRef FilePrefix, StringRef BackendName) const;
   void reset();
 };
-} // end namespace llvm
+} // namespace llvm
 
 #endif // ifndef LLVM_SUPPORT_CODEGENCOVERAGE_H