diff --git a/compiler-rt/lib/profile/InstrProfilingUtil.c b/compiler-rt/lib/profile/InstrProfilingUtil.c
index 95ec4080ba250..c637b9d0b893c 100644
--- a/compiler-rt/lib/profile/InstrProfilingUtil.c
+++ b/compiler-rt/lib/profile/InstrProfilingUtil.c
@@ -152,7 +152,8 @@ COMPILER_RT_VISIBILITY int lprofLockFd(int fd) {
     }
   }
   return 0;
-#elif defined(COMPILER_RT_HAS_FLOCK)
+#elif defined(COMPILER_RT_HAS_FLOCK) || defined(_WIN32)
+  // Windows doesn't have flock but WindowsMMap.h provides a shim
   flock(fd, LOCK_EX);
   return 0;
 #else
@@ -179,7 +180,8 @@ COMPILER_RT_VISIBILITY int lprofUnlockFd(int fd) {
     }
   }
   return 0;
-#elif defined(COMPILER_RT_HAS_FLOCK)
+#elif defined(COMPILER_RT_HAS_FLOCK) || defined(_WIN32)
+  // Windows doesn't have flock but WindowsMMap.h provides a shim
   flock(fd, LOCK_UN);
   return 0;
 #else