diff --git a/llvm/include/llvm/Support/TimeProfiler.h b/llvm/include/llvm/Support/TimeProfiler.h
--- a/llvm/include/llvm/Support/TimeProfiler.h
+++ b/llvm/include/llvm/Support/TimeProfiler.h
@@ -14,7 +14,7 @@
 namespace llvm {
 
 struct TimeTraceProfiler;
-extern thread_local std::unique_ptr<TimeTraceProfiler>
+extern LLVM_THREAD_LOCAL std::unique_ptr<TimeTraceProfiler>
     TimeTraceProfilerInstance;
 
 /// Initialize the time trace profiler.
diff --git a/llvm/lib/Support/TimeProfiler.cpp b/llvm/lib/Support/TimeProfiler.cpp
--- a/llvm/lib/Support/TimeProfiler.cpp
+++ b/llvm/lib/Support/TimeProfiler.cpp
@@ -33,8 +33,7 @@
 
 namespace llvm {
 
-thread_local std::unique_ptr<TimeTraceProfiler> TimeTraceProfilerInstance =
-    nullptr;
+LLVM_THREAD_LOCAL std::unique_ptr<TimeTraceProfiler> TimeTraceProfilerInstance;
 
 typedef duration<steady_clock::rep, steady_clock::period> DurationType;
 typedef time_point<steady_clock> TimePointType;