[libc++] Bump __cpp_lib_optional and __cpp_lib_variant (#113650)

frederick-vs-ja · web-flow · commit cae351f3453a · 2024-10-26T07:38:52.000+08:00
In C++20 mode, `__cpp_lib_optional` and `__cpp_lib_variant` should be `202106L` due to DR P2231R1. In C++26 mode, `__cpp_lib_variant` should be bumped to `202306L` due to P2637R3. - Clang 16/17 shouldn't get this bumping (as member `visit` requires explicit object parameters), but it's very tricky to make the bumping conditionally enabled. I _hope_ unconditionally bumping in C++26 will be OK for LLVM 20 when the support for Clang 17 is dropped. Related PRs: - https://reviews.llvm.org/D102119 - #83335 - #76447
diff --git a/libcxx/docs/FeatureTestMacroTable.rst b/libcxx/docs/FeatureTestMacroTable.rst
@@ -264,6 +264,8 @@ Status
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_move_iterator_concept``                        ``202207L``
     ---------------------------------------------------------- -----------------
+    ``__cpp_lib_optional``                                     ``202106L``
+    ---------------------------------------------------------- -----------------
     ``__cpp_lib_polymorphic_allocator``                        ``201902L``
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_ranges``                                       ``202110L``
@@ -300,6 +302,8 @@ Status
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_unwrap_ref``                                   ``201811L``
     ---------------------------------------------------------- -----------------
+    ``__cpp_lib_variant``                                      ``202106L``
+    ---------------------------------------------------------- -----------------
     **C++23**
     ----------------------------------------------------------------------------
     ``__cpp_lib_adaptor_iterator_pair_constructor``            ``202106L``
@@ -491,5 +495,7 @@ Status
     ``__cpp_lib_to_string``                                    *unimplemented*
     ---------------------------------------------------------- -----------------
     ``__cpp_lib_tuple_like``                                   *unimplemented*
+    ---------------------------------------------------------- -----------------
+    ``__cpp_lib_variant``                                      ``202306L``
     ========================================================== =================
 
diff --git a/libcxx/docs/Status/Cxx20Papers.csv b/libcxx/docs/Status/Cxx20Papers.csv
@@ -192,7 +192,7 @@
 "`P2106R0 <https://wg21.link/P2106R0>`__","Alternative wording for GB315 and GB316","2020-02 (Prague)","|Complete|","15.0",""
 "`P2116R0 <https://wg21.link/P2116R0>`__","Remove tuple-like protocol support from fixed-extent span","2020-02 (Prague)","|Complete|","11.0",""
 "","","","","",""
-"`P2231R1 <https://wg21.link/P2231R1>`__","Missing constexpr in std::optional and std::variant","2021-06 (Virtual)","|Complete|","19.0",""
+"`P2231R1 <https://wg21.link/P2231R1>`__","Missing constexpr in std::optional and std::variant","2021-06 (Virtual)","|Complete|","19.0","Changes of feature-test macros are completed in LLVM 20."
 "`P2325R3 <https://wg21.link/P2325R3>`__","Views should not be required to be default constructible","2021-06 (Virtual)","|Complete|","16.0",""
 "`P2210R2 <https://wg21.link/P2210R2>`__","Superior String Splitting","2021-06 (Virtual)","|Complete|","16.0",""
 "`P2216R3 <https://wg21.link/P2216R3>`__","std::format improvements","2021-06 (Virtual)","|Complete|","15.0",""
diff --git a/libcxx/docs/Status/Cxx2cPapers.csv b/libcxx/docs/Status/Cxx2cPapers.csv
@@ -17,7 +17,7 @@
 "`P0792R14 <https://wg21.link/P0792R14>`__","``function_ref``: a type-erased callable reference","2023-06 (Varna)","","",""
 "`P2874R2 <https://wg21.link/P2874R2>`__","Mandating Annex D Require No More","2023-06 (Varna)","","",""
 "`P2757R3 <https://wg21.link/P2757R3>`__","Type-checking format args","2023-06 (Varna)","","",""
-"`P2637R3 <https://wg21.link/P2637R3>`__","Member ``visit``","2023-06 (Varna)","|Complete|","19.0",""
+"`P2637R3 <https://wg21.link/P2637R3>`__","Member ``visit``","2023-06 (Varna)","|Complete|","19.0","Change of ``__cpp_lib_variant`` is completed in LLVM 20. Change of ``__cpp_lib_format`` is blocked by `P2419R2 <https://wg21.link/P2419R2>`__."
 "`P2641R4 <https://wg21.link/P2641R4>`__","Checking if a ``union`` alternative is active","2023-06 (Varna)","","",""
 "`P1759R6 <https://wg21.link/P1759R6>`__","Native handles and file streams","2023-06 (Varna)","|Complete|","18.0",""
 "`P2697R1 <https://wg21.link/P2697R1>`__","Interfacing ``bitset`` with ``string_view``","2023-06 (Varna)","|Complete|","18.0",""
diff --git a/libcxx/include/version b/libcxx/include/version
@@ -174,6 +174,7 @@ __cpp_lib_nonmember_container_access                    201411L <array> <deque>
 __cpp_lib_not_fn                                        201603L <functional>
 __cpp_lib_null_iterators                                201304L <iterator>
 __cpp_lib_optional                                      202110L <optional>
+                                                        202106L // C++20
                                                         201606L // C++17
 __cpp_lib_optional_range_support                        202406L <optional>
 __cpp_lib_out_ptr                                       202311L <memory>
@@ -261,7 +262,9 @@ __cpp_lib_uncaught_exceptions                           201411L <exception>
 __cpp_lib_unordered_map_try_emplace                     201411L <unordered_map>
 __cpp_lib_unreachable                                   202202L <utility>
 __cpp_lib_unwrap_ref                                    201811L <functional>
-__cpp_lib_variant                                       202102L <variant>
+__cpp_lib_variant                                       202306L <variant>
+                                                        202106L // C++20
+                                                        202102L // C++17
 __cpp_lib_void_t                                        201411L <type_traits>
 
 */
@@ -427,6 +430,8 @@ __cpp_lib_void_t                                        201411L <type_traits>
 # define __cpp_lib_list_remove_return_type              201806L
 # define __cpp_lib_math_constants                       201907L
 # define __cpp_lib_move_iterator_concept                202207L
+# undef  __cpp_lib_optional
+# define __cpp_lib_optional                             202106L
 # if _LIBCPP_AVAILABILITY_HAS_PMR
 #   define __cpp_lib_polymorphic_allocator              201902L
 # endif
@@ -453,6 +458,8 @@ __cpp_lib_void_t                                        201411L <type_traits>
 # define __cpp_lib_to_array                             201907L
 # define __cpp_lib_type_identity                        201806L
 # define __cpp_lib_unwrap_ref                           201811L
+# undef  __cpp_lib_variant
+# define __cpp_lib_variant                              202106L
 #endif
 
 #if _LIBCPP_STD_VER >= 23
@@ -570,6 +577,8 @@ __cpp_lib_void_t                                        201411L <type_traits>
 // # define __cpp_lib_to_string                            202306L
 # undef  __cpp_lib_tuple_like
 // # define __cpp_lib_tuple_like                           202311L
+# undef  __cpp_lib_variant
+# define __cpp_lib_variant                              202306L
 #endif
 
 // clang-format on
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/optional.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/optional.version.compile.pass.cpp
@@ -19,6 +19,7 @@
     __cpp_lib_constrained_equality      202403L [C++26]
     __cpp_lib_freestanding_optional     202311L [C++26]
     __cpp_lib_optional                  201606L [C++17]
+                                        202106L [C++20]
                                         202110L [C++23]
     __cpp_lib_optional_range_support    202406L [C++26]
 */
@@ -96,8 +97,8 @@
 # ifndef __cpp_lib_optional
 #   error "__cpp_lib_optional should be defined in c++20"
 # endif
-# if __cpp_lib_optional != 201606L
-#   error "__cpp_lib_optional should have the value 201606L in c++20"
+# if __cpp_lib_optional != 202106L
+#   error "__cpp_lib_optional should have the value 202106L in c++20"
 # endif
 
 # ifdef __cpp_lib_optional_range_support
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/variant.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/variant.version.compile.pass.cpp
@@ -19,6 +19,8 @@
     __cpp_lib_constrained_equality    202403L [C++26]
     __cpp_lib_freestanding_variant    202311L [C++26]
     __cpp_lib_variant                 202102L [C++17]
+                                      202106L [C++20]
+                                      202306L [C++26]
 */
 
 #include <variant>
@@ -82,8 +84,8 @@
 # ifndef __cpp_lib_variant
 #   error "__cpp_lib_variant should be defined in c++20"
 # endif
-# if __cpp_lib_variant != 202102L
-#   error "__cpp_lib_variant should have the value 202102L in c++20"
+# if __cpp_lib_variant != 202106L
+#   error "__cpp_lib_variant should have the value 202106L in c++20"
 # endif
 
 #elif TEST_STD_VER == 23
@@ -99,8 +101,8 @@
 # ifndef __cpp_lib_variant
 #   error "__cpp_lib_variant should be defined in c++23"
 # endif
-# if __cpp_lib_variant != 202102L
-#   error "__cpp_lib_variant should have the value 202102L in c++23"
+# if __cpp_lib_variant != 202106L
+#   error "__cpp_lib_variant should have the value 202106L in c++23"
 # endif
 
 #elif TEST_STD_VER > 23
@@ -134,8 +136,8 @@
 # ifndef __cpp_lib_variant
 #   error "__cpp_lib_variant should be defined in c++26"
 # endif
-# if __cpp_lib_variant != 202102L
-#   error "__cpp_lib_variant should have the value 202102L in c++26"
+# if __cpp_lib_variant != 202306L
+#   error "__cpp_lib_variant should have the value 202306L in c++26"
 # endif
 
 #endif // TEST_STD_VER > 23
diff --git a/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp b/libcxx/test/std/language.support/support.limits/support.limits.general/version.version.compile.pass.cpp
@@ -158,6 +158,7 @@
     __cpp_lib_not_fn                                        201603L [C++17]
     __cpp_lib_null_iterators                                201304L [C++14]
     __cpp_lib_optional                                      201606L [C++17]
+                                                            202106L [C++20]
                                                             202110L [C++23]
     __cpp_lib_optional_range_support                        202406L [C++26]
     __cpp_lib_out_ptr                                       202106L [C++23]
@@ -244,6 +245,8 @@
     __cpp_lib_unreachable                                   202202L [C++23]
     __cpp_lib_unwrap_ref                                    201811L [C++20]
     __cpp_lib_variant                                       202102L [C++17]
+                                                            202106L [C++20]
+                                                            202306L [C++26]
     __cpp_lib_void_t                                        201411L [C++17]
 */
 
@@ -4087,8 +4090,8 @@
 # ifndef __cpp_lib_optional
 #   error "__cpp_lib_optional should be defined in c++20"
 # endif
-# if __cpp_lib_optional != 201606L
-#   error "__cpp_lib_optional should have the value 201606L in c++20"
+# if __cpp_lib_optional != 202106L
+#   error "__cpp_lib_optional should have the value 202106L in c++20"
 # endif
 
 # ifdef __cpp_lib_optional_range_support
@@ -4569,8 +4572,8 @@
 # ifndef __cpp_lib_variant
 #   error "__cpp_lib_variant should be defined in c++20"
 # endif
-# if __cpp_lib_variant != 202102L
-#   error "__cpp_lib_variant should have the value 202102L in c++20"
+# if __cpp_lib_variant != 202106L
+#   error "__cpp_lib_variant should have the value 202106L in c++20"
 # endif
 
 # ifndef __cpp_lib_void_t
@@ -6196,8 +6199,8 @@
 # ifndef __cpp_lib_variant
 #   error "__cpp_lib_variant should be defined in c++23"
 # endif
-# if __cpp_lib_variant != 202102L
-#   error "__cpp_lib_variant should have the value 202102L in c++23"
+# if __cpp_lib_variant != 202106L
+#   error "__cpp_lib_variant should have the value 202106L in c++23"
 # endif
 
 # ifndef __cpp_lib_void_t
@@ -8141,8 +8144,8 @@
 # ifndef __cpp_lib_variant
 #   error "__cpp_lib_variant should be defined in c++26"
 # endif
-# if __cpp_lib_variant != 202102L
-#   error "__cpp_lib_variant should have the value 202102L in c++26"
+# if __cpp_lib_variant != 202306L
+#   error "__cpp_lib_variant should have the value 202306L in c++26"
 # endif
 
 # ifndef __cpp_lib_void_t
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
@@ -942,7 +942,11 @@ def add_version_header(tc):
         },
         {
             "name": "__cpp_lib_optional",
-            "values": {"c++17": 201606, "c++23": 202110},
+            "values": {
+                "c++17": 201606,
+                "c++20": 202106,  # P2231R1 Missing constexpr in std::optional and std::variant
+                "c++23": 202110,  # P0798R8 Monadic operations for std::optional + LWG3621 Remove feature-test macro __cpp_lib_monadic_optional
+            },
             "headers": ["optional"],
         },
         {
@@ -1406,8 +1410,8 @@ def add_version_header(tc):
             "name": "__cpp_lib_variant",
             "values": {
                 "c++17": 202102,  # std::visit for classes derived from std::variant
-                # "c++20": 202106,  # Fully constexpr std::variant
-                # "c++26": 202306,  # Member visit (implemented)
+                "c++20": 202106,  # P2231R1 Missing constexpr in std::optional and std::variant
+                "c++26": 202306,  # P2637R3 Member visit
             },
             "headers": ["variant"],
         },
