diff --git a/tools/llvm-profdata/llvm-profdata.cpp b/tools/llvm-profdata/llvm-profdata.cpp
index 1bfdb181d7a..6fb48d8fad5 100644
--- a/tools/llvm-profdata/llvm-profdata.cpp
+++ b/tools/llvm-profdata/llvm-profdata.cpp
@@ -37,7 +37,9 @@ static void exitWithError(const Twine &Message, StringRef Whence = "") {
   ::exit(1);
 }
 
+namespace {
 enum ProfileKinds { instr, sample };
+}
 
 static void mergeInstrProfile(const cl::list<std::string> &Inputs,
                               StringRef OutputFilename) {