diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -4,76 +4,76 @@
   __algorithm/any_of.h
   __algorithm/binary_search.h
   __algorithm/clamp.h
-  __algorithm/comp_ref_type.h
   __algorithm/comp.h
+  __algorithm/comp_ref_type.h
+  __algorithm/copy.h
   __algorithm/copy_backward.h
   __algorithm/copy_if.h
   __algorithm/copy_n.h
-  __algorithm/copy.h
-  __algorithm/count_if.h
   __algorithm/count.h
-  __algorithm/equal_range.h
+  __algorithm/count_if.h
   __algorithm/equal.h
-  __algorithm/fill_n.h
+  __algorithm/equal_range.h
   __algorithm/fill.h
+  __algorithm/fill_n.h
+  __algorithm/find.h
   __algorithm/find_end.h
   __algorithm/find_first_of.h
-  __algorithm/find_if_not.h
   __algorithm/find_if.h
-  __algorithm/find.h
-  __algorithm/for_each_n.h
+  __algorithm/find_if_not.h
   __algorithm/for_each.h
-  __algorithm/generate_n.h
+  __algorithm/for_each_n.h
   __algorithm/generate.h
+  __algorithm/generate_n.h
   __algorithm/half_positive.h
   __algorithm/includes.h
   __algorithm/inplace_merge.h
-  __algorithm/is_heap_until.h
   __algorithm/is_heap.h
+  __algorithm/is_heap_until.h
   __algorithm/is_partitioned.h
   __algorithm/is_permutation.h
-  __algorithm/is_sorted_until.h
   __algorithm/is_sorted.h
+  __algorithm/is_sorted_until.h
   __algorithm/iter_swap.h
   __algorithm/lexicographical_compare.h
   __algorithm/lower_bound.h
   __algorithm/make_heap.h
-  __algorithm/max_element.h
   __algorithm/max.h
+  __algorithm/max_element.h
   __algorithm/merge.h
-  __algorithm/min_element.h
   __algorithm/min.h
-  __algorithm/minmax_element.h
+  __algorithm/min_element.h
   __algorithm/minmax.h
+  __algorithm/minmax_element.h
   __algorithm/mismatch.h
-  __algorithm/move_backward.h
   __algorithm/move.h
+  __algorithm/move_backward.h
   __algorithm/next_permutation.h
   __algorithm/none_of.h
   __algorithm/nth_element.h
-  __algorithm/partial_sort_copy.h
   __algorithm/partial_sort.h
+  __algorithm/partial_sort_copy.h
+  __algorithm/partition.h
   __algorithm/partition_copy.h
   __algorithm/partition_point.h
-  __algorithm/partition.h
   __algorithm/pop_heap.h
   __algorithm/prev_permutation.h
   __algorithm/push_heap.h
-  __algorithm/remove_copy_if.h
+  __algorithm/remove.h
   __algorithm/remove_copy.h
+  __algorithm/remove_copy_if.h
   __algorithm/remove_if.h
-  __algorithm/remove.h
-  __algorithm/replace_copy_if.h
+  __algorithm/replace.h
   __algorithm/replace_copy.h
+  __algorithm/replace_copy_if.h
   __algorithm/replace_if.h
-  __algorithm/replace.h
-  __algorithm/reverse_copy.h
   __algorithm/reverse.h
-  __algorithm/rotate_copy.h
+  __algorithm/reverse_copy.h
   __algorithm/rotate.h
+  __algorithm/rotate_copy.h
   __algorithm/sample.h
-  __algorithm/search_n.h
   __algorithm/search.h
+  __algorithm/search_n.h
   __algorithm/set_difference.h
   __algorithm/set_intersection.h
   __algorithm/set_symmetric_difference.h
@@ -82,20 +82,20 @@
   __algorithm/shift_right.h
   __algorithm/shuffle.h
   __algorithm/sift_down.h
-  __algorithm/sort_heap.h
   __algorithm/sort.h
+  __algorithm/sort_heap.h
   __algorithm/stable_partition.h
   __algorithm/stable_sort.h
   __algorithm/swap_ranges.h
   __algorithm/transform.h
-  __algorithm/unique_copy.h
   __algorithm/unique.h
+  __algorithm/unique_copy.h
   __algorithm/unwrap_iter.h
   __algorithm/upper_bound.h
   __availability
-  __bit_reference
   __bit/bit_cast.h
   __bit/byteswap.h
+  __bit_reference
   __bits
   __bsd_locale_defaults.h
   __bsd_locale_fallbacks.h
@@ -150,8 +150,8 @@
   __filesystem/file_type.h
   __filesystem/filesystem_error.h
   __filesystem/operations.h
-  __filesystem/path_iterator.h
   __filesystem/path.h
+  __filesystem/path_iterator.h
   __filesystem/perm_options.h
   __filesystem/perms.h
   __filesystem/recursive_directory_iterator.h
@@ -173,12 +173,11 @@
   __format/formatter_string.h
   __format/parser_std_format_spec.h
   __function_like.h
-  __functional_base
   __functional/binary_function.h
   __functional/binary_negate.h
+  __functional/bind.h
   __functional/bind_back.h
   __functional/bind_front.h
-  __functional/bind.h
   __functional/binder1st.h
   __functional/binder2nd.h
   __functional/compose.h
@@ -201,6 +200,7 @@
   __functional/unary_negate.h
   __functional/unwrap_ref.h
   __functional/weak_result_type.h
+  __functional_base
   __hash_table
   __iterator/access.h
   __iterator/advance.h
@@ -221,8 +221,8 @@
   __iterator/istreambuf_iterator.h
   __iterator/iter_move.h
   __iterator/iter_swap.h
-  __iterator/iterator_traits.h
   __iterator/iterator.h
+  __iterator/iterator_traits.h
   __iterator/move_iterator.h
   __iterator/next.h
   __iterator/ostream_iterator.h
@@ -240,9 +240,9 @@
   __mbstate_t.h
   __memory/addressof.h
   __memory/allocation_guard.h
+  __memory/allocator.h
   __memory/allocator_arg_t.h
   __memory/allocator_traits.h
-  __memory/allocator.h
   __memory/auto_ptr.h
   __memory/compressed_pair.h
   __memory/concepts.h
@@ -257,6 +257,8 @@
   __memory/uses_allocator.h
   __memory/voidify.h
   __mutex_base
+  __node_handle
+  __nullptr
   __numeric/accumulate.h
   __numeric/adjacent_difference.h
   __numeric/exclusive_scan.h
@@ -270,8 +272,6 @@
   __numeric/transform_exclusive_scan.h
   __numeric/transform_inclusive_scan.h
   __numeric/transform_reduce.h
-  __node_handle
-  __nullptr
   __random/bernoulli_distribution.h
   __random/binomial_distribution.h
   __random/cauchy_distribution.h
@@ -317,8 +317,8 @@
   __ranges/dangling.h
   __ranges/data.h
   __ranges/drop_view.h
-  __ranges/empty_view.h
   __ranges/empty.h
+  __ranges/empty_view.h
   __ranges/enable_borrowed_range.h
   __ranges/enable_view.h
   __ranges/iota_view.h
@@ -500,8 +500,8 @@
   stdlib.h
   streambuf
   string
-  string_view
   string.h
+  string_view
   strstream
   system_error
   tgmath.h
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -430,8 +430,8 @@
     module __coroutine {
       module coroutine_handle           { private header "__coroutine/coroutine_handle.h" }
       module coroutine_traits           { private header "__coroutine/coroutine_traits.h" }
-      module trivial_awaitables         { private header "__coroutine/trivial_awaitables.h" }
       module noop_coroutine_handle      { private header "__coroutine/noop_coroutine_handle.h" }
+      module trivial_awaitables         { private header "__coroutine/trivial_awaitables.h" }
     }
   }
   module deque {
@@ -461,8 +461,8 @@
       module file_type                    { private header "__filesystem/file_type.h" }
       module filesystem_error             { private header "__filesystem/filesystem_error.h" }
       module operations                   { private header "__filesystem/operations.h" }
-      module path_iterator                { private header "__filesystem/path_iterator.h" }
       module path                         { private header "__filesystem/path.h" }
+      module path_iterator                { private header "__filesystem/path_iterator.h" }
       module perm_options                 { private header "__filesystem/perm_options.h" }
       module perms                        { private header "__filesystem/perms.h" }
       module recursive_directory_iterator { private header "__filesystem/recursive_directory_iterator.h" }
@@ -797,8 +797,8 @@
       module range_adaptor          { private header "__ranges/range_adaptor.h" }
       module ref_view               { private header "__ranges/ref_view.h" }
       module reverse_view           { private header "__ranges/reverse_view.h" }
-      module size                   { private header "__ranges/size.h" }
       module single_view            { private header "__ranges/single_view.h" }
+      module size                   { private header "__ranges/size.h" }
       module subrange               { private header "__ranges/subrange.h" }
       module take_view              { private header "__ranges/take_view.h" }
       module transform_view         {
diff --git a/libcxx/utils/CMakeLists.txt b/libcxx/utils/CMakeLists.txt
--- a/libcxx/utils/CMakeLists.txt
+++ b/libcxx/utils/CMakeLists.txt
@@ -15,9 +15,19 @@
     COMMAND "${Python3_EXECUTABLE}" "${LIBCXX_SOURCE_DIR}/utils/generate_private_header_tests.py"
     COMMENT "Generate tests for ensuring that detail headers are private.")
 
+add_custom_target(libcxx-lint-cmakelists
+    COMMAND "${Python3_EXECUTABLE}" "${LIBCXX_SOURCE_DIR}/utils/lint_cmakelists.py"
+    COMMENT "Verify that the libc++ CMakeLists.txt is in alphabetical order.")
+
+add_custom_target(libcxx-lint-modulemap
+    COMMAND "${Python3_EXECUTABLE}" "${LIBCXX_SOURCE_DIR}/utils/lint_modulemap.py"
+    COMMENT "Verify that the libc++ modulemap is in alphabetical order.")
+
 add_custom_target(libcxx-generate-files
     DEPENDS libcxx-generate-public-header-transitive-inclusion-tests
             libcxx-generate-public-header-tests
             libcxx-generate-feature-test-macros
             libcxx-generate-private-header-tests
+            libcxx-lint-cmakelists
+            libcxx-lint-modulemap
     COMMENT "Create all the auto-generated files in libc++ and its tests.")
diff --git a/libcxx/utils/lint_cmakelists.py b/libcxx/utils/lint_cmakelists.py
new file mode 100644
--- /dev/null
+++ b/libcxx/utils/lint_cmakelists.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+
+import os
+
+
+def get_cmakelists_name():
+    utils_path = os.path.dirname(os.path.abspath(__file__))
+    assert os.path.exists(utils_path)
+    cmakelists_name = os.path.join(os.path.dirname(utils_path), 'include', 'CMakeLists.txt')
+    assert os.path.exists(cmakelists_name)
+    return cmakelists_name
+
+
+if __name__ == '__main__':
+    with open(get_cmakelists_name(), 'r') as f:
+        lines = f.readlines()
+    assert lines[0] == 'set(files\n'
+
+    okay = True
+    prevline = lines[1]
+    for line in lines[2:]:
+        if (line == '  )\n'):
+            break
+        if (line < prevline):
+            okay = False
+            print('LINES OUT OF ORDER in libcxx/include/CMakeLists.txt!')
+            print(prevline)
+            print(line)
+        prevline = line
+    assert okay
diff --git a/libcxx/utils/lint_modulemap.py b/libcxx/utils/lint_modulemap.py
new file mode 100644
--- /dev/null
+++ b/libcxx/utils/lint_modulemap.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python
+
+import os
+import re
+
+
+def get_modulemap_name():
+    utils_path = os.path.dirname(os.path.abspath(__file__))
+    assert os.path.exists(utils_path)
+    modulemap_name = os.path.join(os.path.dirname(utils_path), 'include', 'module.modulemap')
+    assert os.path.exists(modulemap_name)
+    return modulemap_name
+
+
+if __name__ == '__main__':
+    okay = True
+    prevline = None
+    with open(get_modulemap_name(), 'r') as f:
+        for line in f.readlines():
+            if re.match(r'^\s*module.*[{]\s*private', line):
+                if (prevline is not None) and (line < prevline):
+                    okay = False
+                    print('LINES OUT OF ORDER in libcxx/include/module.modulemap!')
+                    print(prevline)
+                    print(line)
+                prevline = line
+            else:
+                prevline = None
+    assert okay