diff --git a/libcxx/test/libcxx/containers/sequences/array/array.zero/db_back.pass.cpp b/libcxx/test/libcxx/containers/sequences/array/array.zero/db_back.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/array/array.zero/db_back.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/array/array.zero/db_back.pass.cpp
@@ -10,7 +10,7 @@
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test array<T, 0>::front() raises a debug error.
diff --git a/libcxx/test/libcxx/containers/sequences/array/array.zero/db_front.pass.cpp b/libcxx/test/libcxx/containers/sequences/array/array.zero/db_front.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/array/array.zero/db_front.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/array/array.zero/db_front.pass.cpp
@@ -10,7 +10,7 @@
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test array<T, 0>::front() raises a debug error.
diff --git a/libcxx/test/libcxx/containers/sequences/array/array.zero/db_indexing.pass.cpp b/libcxx/test/libcxx/containers/sequences/array/array.zero/db_indexing.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/array/array.zero/db_indexing.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/array/array.zero/db_indexing.pass.cpp
@@ -10,7 +10,7 @@
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test array<T, 0>::operator[] raises a debug error.
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.cons/db_copy.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.cons/db_copy.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.cons/db_copy.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.cons/db_copy.pass.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 // <list>
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // list(list&& c);
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.cons/db_move.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.cons/db_move.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.cons/db_move.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.cons/db_move.pass.cpp
@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++98, c++03
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/emplace_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/emplace_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/emplace_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/emplace_db1.pass.cpp
@@ -8,7 +8,7 @@
 
 // UNSUPPORTED: c++98, c++03
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db2.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db2.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db2.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_db2.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db2.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db2.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db2.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db2.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db3.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db3.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db3.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db3.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db4.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db4.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db4.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/erase_iter_iter_db4.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_iter_iter_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_iter_iter_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_iter_iter_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_iter_iter_db1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_rvalue_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_rvalue_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_rvalue_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_rvalue_db1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_size_value_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_size_value_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_size_value_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_size_value_db1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_value_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_value_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_value_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/insert_iter_value_db1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/pop_back_db1.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/pop_back_db1.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.modifiers/pop_back_db1.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.modifiers/pop_back_db1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter_iter.pass.cpp b/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter_iter.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter_iter.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/list/list.ops/db_splice_pos_list_iter_iter.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <list>
diff --git a/libcxx/test/libcxx/debug/containers/db_associative_container_tests.pass.cpp b/libcxx/test/libcxx/debug/containers/db_associative_container_tests.pass.cpp
--- a/libcxx/test/libcxx/debug/containers/db_associative_container_tests.pass.cpp
+++ b/libcxx/test/libcxx/debug/containers/db_associative_container_tests.pass.cpp
@@ -11,7 +11,7 @@
 // UNSUPPORTED: libcpp-no-if-constexpr
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test container debugging
diff --git a/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.multithread.pass.cpp b/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.multithread.pass.cpp
--- a/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.multithread.pass.cpp
+++ b/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.multithread.pass.cpp
@@ -11,7 +11,7 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test multihtreaded container debugging
diff --git a/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.pass.cpp b/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.pass.cpp
--- a/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.pass.cpp
+++ b/libcxx/test/libcxx/debug/containers/db_sequence_container_iterators.pass.cpp
@@ -11,7 +11,7 @@
 // UNSUPPORTED: libcpp-no-if-constexpr
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test container debugging
diff --git a/libcxx/test/libcxx/debug/containers/db_string.pass.cpp b/libcxx/test/libcxx/debug/containers/db_string.pass.cpp
--- a/libcxx/test/libcxx/debug/containers/db_string.pass.cpp
+++ b/libcxx/test/libcxx/debug/containers/db_string.pass.cpp
@@ -11,7 +11,7 @@
 // UNSUPPORTED: libcpp-no-if-constexpr
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test container debugging
diff --git a/libcxx/test/libcxx/debug/containers/db_unord_container_tests.pass.cpp b/libcxx/test/libcxx/debug/containers/db_unord_container_tests.pass.cpp
--- a/libcxx/test/libcxx/debug/containers/db_unord_container_tests.pass.cpp
+++ b/libcxx/test/libcxx/debug/containers/db_unord_container_tests.pass.cpp
@@ -11,7 +11,7 @@
 // UNSUPPORTED: libcpp-no-if-constexpr
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // test container debugging
diff --git a/libcxx/test/libcxx/debug/debug_abort.pass.cpp b/libcxx/test/libcxx/debug/debug_abort.pass.cpp
--- a/libcxx/test/libcxx/debug/debug_abort.pass.cpp
+++ b/libcxx/test/libcxx/debug/debug_abort.pass.cpp
@@ -9,7 +9,7 @@
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=0
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // Test that the default debug handler aborts the program.
diff --git a/libcxx/test/libcxx/debug/debug_helper_test.pass.cpp b/libcxx/test/libcxx/debug/debug_helper_test.pass.cpp
--- a/libcxx/test/libcxx/debug/debug_helper_test.pass.cpp
+++ b/libcxx/test/libcxx/debug/debug_helper_test.pass.cpp
@@ -10,7 +10,7 @@
 // UNSUPPORTED: c++98, c++03
 // UNSUPPORTED: windows
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
diff --git a/libcxx/test/libcxx/debug/debug_register.pass.cpp b/libcxx/test/libcxx/debug/debug_register.pass.cpp
--- a/libcxx/test/libcxx/debug/debug_register.pass.cpp
+++ b/libcxx/test/libcxx/debug/debug_register.pass.cpp
@@ -9,7 +9,7 @@
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 #define _LIBCPP_DEBUG 1
diff --git a/libcxx/test/libcxx/iterators/advance.debug1.pass.cpp b/libcxx/test/libcxx/iterators/advance.debug1.pass.cpp
--- a/libcxx/test/libcxx/iterators/advance.debug1.pass.cpp
+++ b/libcxx/test/libcxx/iterators/advance.debug1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 // UNSUPPORTED: c++98, c++03
 // UNSUPPORTED: windows
diff --git a/libcxx/test/libcxx/iterators/next.debug1.pass.cpp b/libcxx/test/libcxx/iterators/next.debug1.pass.cpp
--- a/libcxx/test/libcxx/iterators/next.debug1.pass.cpp
+++ b/libcxx/test/libcxx/iterators/next.debug1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 // UNSUPPORTED: c++98, c++03
 // UNSUPPORTED: windows
diff --git a/libcxx/test/libcxx/iterators/prev.debug1.pass.cpp b/libcxx/test/libcxx/iterators/prev.debug1.pass.cpp
--- a/libcxx/test/libcxx/iterators/prev.debug1.pass.cpp
+++ b/libcxx/test/libcxx/iterators/prev.debug1.pass.cpp
@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // MODULES_DEFINES: _LIBCPP_DEBUG=1
 // UNSUPPORTED: with_system_cxx_lib
 // UNSUPPORTED: c++98, c++03
diff --git a/libcxx/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp b/libcxx/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp
--- a/libcxx/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp
+++ b/libcxx/test/libcxx/thread/futures/futures.promise/set_exception.pass.cpp
@@ -12,7 +12,7 @@
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=0
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <future>
diff --git a/libcxx/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp b/libcxx/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
--- a/libcxx/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
+++ b/libcxx/test/libcxx/thread/futures/futures.promise/set_exception_at_thread_exit.pass.cpp
@@ -12,7 +12,7 @@
 
 // MODULES_DEFINES: _LIBCPP_DEBUG=0
 
-// Can't test the system lib because this test enables debug mode
+// REQUIRES: debug-mode
 // UNSUPPORTED: with_system_cxx_lib
 
 // <future>
diff --git a/libcxx/utils/libcxx/test/config.py b/libcxx/utils/libcxx/test/config.py
--- a/libcxx/utils/libcxx/test/config.py
+++ b/libcxx/utils/libcxx/test/config.py
@@ -879,6 +879,8 @@
         if debug_level not in ['0', '1']:
             self.lit_config.fatal('Invalid value for debug_level "%s".'
                                   % debug_level)
+        elif debug_level == '1':
+            self.config.available_features.add('debug-mode')
         self.cxx.compile_flags += ['-D_LIBCPP_DEBUG=%s' % debug_level]
 
     def configure_warnings(self):