[libcxx-commits] [libcxx] [libc++] Implements the new version header generator. (PR #97847)

[S. B. Tam via libcxx-commits]

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@@ -0,0 +1,73 @@
+# ===----------------------------------------------------------------------===##
+#
+# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# ===----------------------------------------------------------------------===##
+
+# RUN: %{python} %s %{libcxx-dir}/utils %{libcxx-dir}/test/libcxx/feature_test_macro/test_data.json
+
+import sys
+
+sys.path.append(sys.argv[1])
+from generate_feature_test_macro_components import FeatureTestMacros
+
+
+def test(output, expected):
+    assert output == expected, f"expected\n{expected}\n\noutput\n{output}"
+
+
+ftm = FeatureTestMacros(sys.argv[2])
+test(
+    ftm.version_header,
+    """// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_VERSION
+#define _LIBCPP_VERSION
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 17
+#  define __cpp_lib_any 201606L
+#  define __cpp_lib_parallel_algorithm 201603L
+#  define __cpp_lib_variant 202102L
+#endif // _LIBCPP_STD_VER >= 17
+
+#if _LIBCPP_STD_VER >= 20
+#  if !defined(_LIBCPP_HAS_NO_THREADS) && _LIBCPP_AVAILABILITY_HAS_SYNC
+#    define __cpp_lib_barrier 201907L
+#  endif
+// define __cpp_lib_format 202110L
+#  undef __cpp_lib_variant
+#  define __cpp_lib_variant 202106L
----------------
cpplearner wrote:

The output seems incorrect: this value is marked as `"implemented": false` in `test_data.json`, and thus it should not be defined in the generated output.

https://github.com/llvm/llvm-project/blob/a149e3919a5de7a43d933aa99c1cb6697e597d39/libcxx/test/libcxx/feature_test_macro/test_data.json#L136-L142

(I noticed this while working on [an up-to-date FTM data file](https://github.com/cpplearner/llvm-project/blob/ftm-data/libcxx/utils/feature_test_macro_data.json).

https://github.com/llvm/llvm-project/pull/97847