diff --git a/libcxxabi/test/libcxxabi/test/config.py b/libcxxabi/test/libcxxabi/test/config.py
--- a/libcxxabi/test/libcxxabi/test/config.py
+++ b/libcxxabi/test/libcxxabi/test/config.py
@@ -44,7 +44,6 @@
 
     def configure_compile_flags(self):
         self.cxx.compile_flags += [
-            '-DLIBCXXABI_NO_TIMER',
             '-D_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS',
         ]
         if self.get_lit_bool('enable_exceptions', True):
diff --git a/libcxxabi/test/support/timer.h b/libcxxabi/test/support/timer.h
--- a/libcxxabi/test/support/timer.h
+++ b/libcxxabi/test/support/timer.h
@@ -9,8 +9,8 @@
 #ifndef TIMER_H
 #define TIMER_H
 
-// Define LIBCXXABI_NO_TIMER to disable testing with a timer.
-#ifndef LIBCXXABI_NO_TIMER
+// Define LIBCXXABI_USE_TIMER to enable testing with a timer.
+#ifndef LIBCXXABI_USE_TIMER
 
 #include <chrono>
 #include <cstdio>
@@ -38,7 +38,7 @@
     TimePoint m_start;
 };
 
-#else /* LIBCXXABI_NO_TIMER */
+#else /* LIBCXXABI_USE_TIMER */
 
 class timer
 {
@@ -49,6 +49,6 @@
     ~timer() {}
 };
 
-#endif /* LIBCXXABI_NO_TIMER */
+#endif /* LIBCXXABI_USE_TIMER */
 
 #endif /* TIMER_H */
diff --git a/libunwind/test/libunwind/test/config.py b/libunwind/test/libunwind/test/config.py
--- a/libunwind/test/libunwind/test/config.py
+++ b/libunwind/test/libunwind/test/config.py
@@ -39,7 +39,6 @@
             self.config.available_features.add('libunwind-arm-ehabi')
 
     def configure_compile_flags(self):
-        self.cxx.compile_flags += ['-DLIBUNWIND_NO_TIMER']
         # Stack unwinding tests need unwinding tables and these are not
         # generated by default on all Targets.
         self.cxx.compile_flags += ['-funwind-tables']