diff --git a/llvm/lib/Support/ThreadPool.cpp b/llvm/lib/Support/ThreadPool.cpp
--- a/llvm/lib/Support/ThreadPool.cpp
+++ b/llvm/lib/Support/ThreadPool.cpp
@@ -117,6 +117,10 @@
   }
 }
 
+bool ThreadPool::isWorkerThread() const {
+  assert(false && "LLVM compiled with threading disabled");
+}
+
 ThreadPool::~ThreadPool() { wait(); }
 
 #endif