[libcxx] cleans up __cpp_concepts mess

[cjdb]

Summary

libc++ was previously a bit confused by what the value of __cpp_concepts
should be. Also replaces __floating_point with floating_point now
that it exists.

[miscco]

Looks good to me

*Insert obligatory rant about double negation*

[miscco]

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp

2886

Could we clean that up to use!__LIBCPP_HAS_NO_CONCEPTS

[ldionne]

Thanks!

[Mordante]

It seems this fails to build on Apple due to an issue in _LIBCPP_HAS_NO_CONCEPTS. I'll fix that in main this weekend.

[cjdb]

applies @miscco's fix

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp

2886

🤦Done.

[Mordante]

1a5c92f68021 should fix this patch. Can you rebase on main to see whether the CI passes for this patch?

[cjdb]

rebases to activate CI

[Mordante]

libcxx/include/concepts

152

I see !_LIBCPP_HAS_NO_CONCEPTS instead of !defined(_LIBCPP_HAS_NO_CONCEPTS) at several places in this patch. Probably part of the new build failures.

[cjdb]

fixes silly preprocessor mistake

[ldionne]

libcxx/include/numbers

103–115

Assuming you didn't change the value of these constants :-)

[cjdb]

This comment was removed by cjdb.

[• Quuxplusone]

@cjdb, after this landed and then @zoecarver's D60368 landed on top of it and maybe merge-conflicted with it... I'm now seeing that the feature-test-macro tests that are checked in do not match the output you get by running the libcxx/utils/generate_feature_test_macro_components.py script. Could you (@cjdb) run libcxx/utils/generate_feature_test_macro_components.py locally, check whether it matches what you intended, and if so, check in those changes? (If the generated output doesn't match what you intended, then probably you should post another PR.)

[cjdb]

In D97015#2599338, @Quuxplusone wrote:

@cjdb, after this landed and then @zoecarver's D60368 landed on top of it and maybe merge-conflicted with it... I'm now seeing that the feature-test-macro tests that are checked in do not match the output you get by running the libcxx/utils/generate_feature_test_macro_components.py script. Could you (@cjdb) run libcxx/utils/generate_feature_test_macro_components.py locally, check whether it matches what you intended, and if so, check in those changes? (If the generated output doesn't match what you intended, then probably you should post another PR.)

Nice catch! Looking at the diff here, it appears that I didnt' change libcxx/utils/generate_feature_test_macro_components.py properly. Making a patch for it now.

libcxx/include/concepts

 #pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
+#if _LIBCPP_STD_VER > 17 && !_LIBCPP_HAS_NO_CONCEPTS
 
 // [concept.same]
 
 template<class _Tp, class _Up>
 concept __same_as_impl = _VSTD::_IsSame<_Tp, _Up>::value;
 
 template<class _Tp, class _Up>
 concept same_as = __same_as_impl<_Tp, _Up> && __same_as_impl<_Up, _Tp>;

 concept invocable = requires(_Fn&& __fn, _Args&&... __args) {
   _VSTD::invoke(_VSTD::forward<_Fn>(__fn), _VSTD::forward<_Args>(__args)...); // not required to be equality preserving
 };
 
 // [concept.regular.invocable]
 template<class _Fn, class... _Args>
 concept regular_invocable = invocable<_Fn, _Args...>;
 
-#endif // _LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
+#endif // _LIBCPP_STD_VER > 17 && !_LIBCPP_HAS_NO_CONCEPTS
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
 #endif // _LIBCPP_CONCEPTS

libcxx/include/numbers

namespace std::numbers {
   inline constexpr double inv_sqrt3  = inv_sqrt3_v<double>;
   inline constexpr double egamma     = egamma_v<double>;
   inline constexpr double phi        = phi_v<double>;
 }
 */
 
 #include <__config>
 
-#if _LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
+#if _LIBCPP_STD_VER > 17 && !_LIBCPP_HAS_NO_CONCEPTS
 
+#include <concepts>
 #include <type_traits>
 #include <version>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
 _LIBCPP_PUSH_MACROS

 template <class T> inline constexpr T ln2_v =        __illformed<T>{};
 template <class T> inline constexpr T ln10_v =       __illformed<T>{};
 template <class T> inline constexpr T sqrt2_v =      __illformed<T>{};
 template <class T> inline constexpr T sqrt3_v =      __illformed<T>{};
 template <class T> inline constexpr T inv_sqrt3_v =  __illformed<T>{};
 template <class T> inline constexpr T egamma_v =     __illformed<T>{};
 template <class T> inline constexpr T phi_v =        __illformed<T>{};
 
-template <class T>
-concept __floating_point = is_floating_point_v<T>;
-
-template <__floating_point T> inline constexpr T e_v<T>          = 2.718281828459045235360287471352662;
-template <__floating_point T> inline constexpr T log2e_v<T>      = 1.442695040888963407359924681001892;
-template <__floating_point T> inline constexpr T log10e_v<T>     = 0.434294481903251827651128918916605;
-template <__floating_point T> inline constexpr T pi_v<T>         = 3.141592653589793238462643383279502;
-template <__floating_point T> inline constexpr T inv_pi_v<T>     = 0.318309886183790671537767526745028;
-template <__floating_point T> inline constexpr T inv_sqrtpi_v<T> = 0.564189583547756286948079451560772;
-template <__floating_point T> inline constexpr T ln2_v<T>        = 0.693147180559945309417232121458176;
-template <__floating_point T> inline constexpr T ln10_v<T>       = 2.302585092994045684017991454684364;
-template <__floating_point T> inline constexpr T sqrt2_v<T>      = 1.414213562373095048801688724209698;
-template <__floating_point T> inline constexpr T sqrt3_v<T>      = 1.732050807568877293527446341505872;
-template <__floating_point T> inline constexpr T inv_sqrt3_v<T>  = 0.577350269189625764509148780501957;
-template <__floating_point T> inline constexpr T egamma_v<T>     = 0.577215664901532860606512090082402;
-template <__floating_point T> inline constexpr T phi_v<T>        = 1.618033988749894848204586834365638;
+template <floating_point T> inline constexpr T e_v<T>          = 2.718281828459045235360287471352662;
+template <floating_point T> inline constexpr T log2e_v<T>      = 1.442695040888963407359924681001892;
+template <floating_point T> inline constexpr T log10e_v<T>     = 0.434294481903251827651128918916605;
+template <floating_point T> inline constexpr T pi_v<T>         = 3.141592653589793238462643383279502;
+template <floating_point T> inline constexpr T inv_pi_v<T>     = 0.318309886183790671537767526745028;
+template <floating_point T> inline constexpr T inv_sqrtpi_v<T> = 0.564189583547756286948079451560772;
+template <floating_point T> inline constexpr T ln2_v<T>        = 0.693147180559945309417232121458176;
+template <floating_point T> inline constexpr T ln10_v<T>       = 2.302585092994045684017991454684364;
+template <floating_point T> inline constexpr T sqrt2_v<T>      = 1.414213562373095048801688724209698;
+template <floating_point T> inline constexpr T sqrt3_v<T>      = 1.732050807568877293527446341505872;
+template <floating_point T> inline constexpr T inv_sqrt3_v<T>  = 0.577350269189625764509148780501957;
+template <floating_point T> inline constexpr T egamma_v<T>     = 0.577215664901532860606512090082402;
+template <floating_point T> inline constexpr T phi_v<T>        = 1.618033988749894848204586834365638;
 
 inline constexpr double e          = e_v<double>;
 inline constexpr double log2e      = log2e_v<double>;
 inline constexpr double log10e     = log10e_v<double>;
 inline constexpr double pi         = pi_v<double>;
 inline constexpr double inv_pi     = inv_pi_v<double>;
 inline constexpr double inv_sqrtpi = inv_sqrtpi_v<double>;
 inline constexpr double ln2        = ln2_v<double>;
 inline constexpr double ln10       = ln10_v<double>;
 inline constexpr double sqrt2      = sqrt2_v<double>;
 inline constexpr double sqrt3      = sqrt3_v<double>;
 inline constexpr double inv_sqrt3  = inv_sqrt3_v<double>;
 inline constexpr double egamma     = egamma_v<double>;
 inline constexpr double phi        = phi_v<double>;
 
 } // namespace numbers
 
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
-#endif //_LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
+#endif //_LIBCPP_STD_VER > 17 && !_LIBCPP_HAS_NO_CONCEPTS
 
 #endif // _LIBCPP_NUMBERS

libcxx/include/random

 #endif
 
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#if _LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
+#if _LIBCPP_STD_VER > 17 && !_LIBCPP_HAS_NO_CONCEPTS
 
 // [rand.req.urng]
 template<class _Gen>
 concept uniform_random_bit_generator =
   invocable<_Gen&> && unsigned_integral<invoke_result_t<_Gen&>> &&
   requires {
     { _Gen::min() } -> same_as<invoke_result_t<_Gen&>>;
     { _Gen::max() } -> same_as<invoke_result_t<_Gen&>>;
     requires bool_constant<(_Gen::min() < _Gen::max())>::value;
   };
 
-#endif // _LIBCPP_STD_VER > 17 && defined(__cpp_concepts) && __cpp_concepts >= 201811L
+#endif // _LIBCPP_STD_VER > 17 && !_LIBCPP_HAS_NO_CONCEPTS
 
 // __is_seed_sequence
 
 template <class _Sseq, class _Engine>
 struct __is_seed_sequence
 {
     static _LIBCPP_CONSTEXPR const bool value =
               !is_convertible<_Sseq, typename _Engine::result_type>::value &&

libcxx/include/version

 // # define __cpp_lib_is_pointer_interconvertible          201907L
 # if !defined(_LIBCPP_HAS_NO_THREADS)
 // #   define __cpp_lib_jthread                            201911L
 # endif
 # if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_latch)
 #   define __cpp_lib_latch                              201907L
 # endif
 # define __cpp_lib_list_remove_return_type              201806L
-# if defined(__cpp_concepts) && __cpp_concepts >= 201811L
+# if !_LIBCPP_HAS_NO_CONCEPTS
 #   define __cpp_lib_math_constants                     201907L
 # endif
 // # define __cpp_lib_polymorphic_allocator                201902L
 // # define __cpp_lib_ranges                               201811L
 # define __cpp_lib_remove_cvref                         201711L
 # if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(_LIBCPP_AVAILABILITY_DISABLE_FTM___cpp_lib_semaphore)
 #   define __cpp_lib_semaphore                          201907L
 # endif

libcxx/test/std/language.support/support.limits/support.limits.general/numbers.version.pass.cpp

 #elif TEST_STD_VER == 17
 
 # ifdef __cpp_lib_math_constants
 #   error "__cpp_lib_math_constants should not be defined before c++20"
 # endif
 
 #elif TEST_STD_VER == 20
 
-# if defined(__cpp_concepts) && __cpp_concepts >= 201811L
+# if !_LIBCPP_HAS_NO_CONCEPTS
 #   ifndef __cpp_lib_math_constants
 #     error "__cpp_lib_math_constants should be defined in c++20"
 #   endif
 #   if __cpp_lib_math_constants != 201907L
 #     error "__cpp_lib_math_constants should have the value 201907L in c++20"
 #   endif
 # else
 #   ifdef __cpp_lib_math_constants
-#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201811L is not defined!"
+#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201907L is not defined!"
 #   endif
 # endif
 
 #elif TEST_STD_VER > 20
 
-# if defined(__cpp_concepts) && __cpp_concepts >= 201811L
+# if !_LIBCPP_HAS_NO_CONCEPTS
 #   ifndef __cpp_lib_math_constants
 #     error "__cpp_lib_math_constants should be defined in c++2b"
 #   endif
 #   if __cpp_lib_math_constants != 201907L
 #     error "__cpp_lib_math_constants should have the value 201907L in c++2b"
 #   endif
 # else
 #   ifdef __cpp_lib_math_constants
-#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201811L is not defined!"
+#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201907L is not defined!"
 #   endif
 # endif
 
 #endif // TEST_STD_VER > 20
 
 int main(int, char**) { return 0; }

libcxx/test/std/language.support/support.limits/support.limits.general/version.version.pass.cpp

 
 # ifndef __cpp_lib_map_try_emplace
 #   error "__cpp_lib_map_try_emplace should be defined in c++20"
 # endif
 # if __cpp_lib_map_try_emplace != 201411L
 #   error "__cpp_lib_map_try_emplace should have the value 201411L in c++20"
 # endif
 
-# if defined(__cpp_concepts) && __cpp_concepts >= 201811L
+# if !_LIBCPP_HAS_NO_CONCEPTS
 #   ifndef __cpp_lib_math_constants
 #     error "__cpp_lib_math_constants should be defined in c++20"
 #   endif
 #   if __cpp_lib_math_constants != 201907L
 #     error "__cpp_lib_math_constants should have the value 201907L in c++20"
 #   endif
 # else
 #   ifdef __cpp_lib_math_constants
-#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201811L is not defined!"
-#   endif
-# endif
+#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201907L is not defined!"
+#   endif
+# endif // !_LIBCPP_HAS_NO_CONCEPTS
 
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_math_special_functions
 #     error "__cpp_lib_math_special_functions should be defined in c++20"
 #   endif
 #   if __cpp_lib_math_special_functions != 201603L
 #     error "__cpp_lib_math_special_functions should have the value 201603L in c++20"
 #   endif

 
 # ifndef __cpp_lib_map_try_emplace
 #   error "__cpp_lib_map_try_emplace should be defined in c++2b"
 # endif
 # if __cpp_lib_map_try_emplace != 201411L
 #   error "__cpp_lib_map_try_emplace should have the value 201411L in c++2b"
 # endif
 
-# if defined(__cpp_concepts) && __cpp_concepts >= 201811L
+# if !_LIBCPP_HAS_NO_CONCEPTS
 #   ifndef __cpp_lib_math_constants
 #     error "__cpp_lib_math_constants should be defined in c++2b"
 #   endif
 #   if __cpp_lib_math_constants != 201907L
 #     error "__cpp_lib_math_constants should have the value 201907L in c++2b"
 #   endif
 # else
 #   ifdef __cpp_lib_math_constants
-#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201811L is not defined!"
-#   endif
-# endif
+#     error "__cpp_lib_math_constants should not be defined when defined(__cpp_concepts) && __cpp_concepts >= 201907L is not defined!"
+#   endif
+# endif // !_LIBCPP_HAS_NO_CONCEPTS
 
 # if !defined(_LIBCPP_VERSION)
 #   ifndef __cpp_lib_math_special_functions
 #     error "__cpp_lib_math_special_functions should be defined in c++2b"
 #   endif
 #   if __cpp_lib_math_special_functions != 201603L
 #     error "__cpp_lib_math_special_functions should have the value 201603L in c++2b"
 #   endif

libcxx/utils/generate_feature_test_macro_components.py

feature_test_macros = [ add_version_header(x) for x in [
   }, {
     "name": "__cpp_lib_map_try_emplace",
     "values": { "c++17": 201411 },
     "headers": ["map"],
   }, {
     "name": "__cpp_lib_math_constants",
     "values": { "c++20": 201907 },
     "headers": ["numbers"],
-    "depends": "defined(__cpp_concepts) && __cpp_concepts >= 201811L",
-    "internal_depends": "defined(__cpp_concepts) && __cpp_concepts >= 201811L",
+    "depends": "defined(__cpp_concepts) && __cpp_concepts >= 201907L",
+    "internal_depends": "defined(__cpp_concepts) && __cpp_concepts >= 201907L",
   }, {
     "name": "__cpp_lib_math_special_functions",
     "values": { "c++17": 201603 },
     "headers": ["cmath"],
     "unimplemented": True,
   }, {
     "name": "__cpp_lib_memory_resource",
     "values": { "c++17": 201603 },

libcxx/utils/libcxx/test/features.py

DEFAULT_FEATURES = [
 
   Feature(name='has-fblocks',                   when=lambda cfg: hasCompileFlag(cfg, '-fblocks')),
   Feature(name='-fsized-deallocation',          when=lambda cfg: hasCompileFlag(cfg, '-fsized-deallocation')),
   Feature(name='-faligned-allocation',          when=lambda cfg: hasCompileFlag(cfg, '-faligned-allocation')),
   Feature(name='fdelayed-template-parsing',     when=lambda cfg: hasCompileFlag(cfg, '-fdelayed-template-parsing')),
   Feature(name='libcpp-no-if-constexpr',        when=lambda cfg: '__cpp_if_constexpr' not in featureTestMacros(cfg)),
   Feature(name='libcpp-no-structured-bindings', when=lambda cfg: '__cpp_structured_bindings' not in featureTestMacros(cfg)),
   Feature(name='libcpp-no-deduction-guides',    when=lambda cfg: featureTestMacros(cfg).get('__cpp_deduction_guides', 0) < 201611),
-  Feature(name='libcpp-no-concepts',            when=lambda cfg: featureTestMacros(cfg).get('__cpp_concepts', 0) < 201811),
+  Feature(name='libcpp-no-concepts',            when=lambda cfg: featureTestMacros(cfg).get('__cpp_concepts', 0) < 201907),
   Feature(name='has-fobjc-arc',                 when=lambda cfg: hasCompileFlag(cfg, '-xobjective-c++ -fobjc-arc') and
                                                                  sys.platform.lower().strip() == 'darwin'), # TODO: this doesn't handle cross-compiling to Apple platforms.
   Feature(name='objective-c++',                 when=lambda cfg: hasCompileFlag(cfg, '-xobjective-c++ -fobjc-arc')),
 
   # Note: We use a custom modules cache path to make sure that we don't reuse
   #       the default one, which can be shared across builds. This is important
   #       because we define macros in headers files, and a change in these macros
   #       doesn't seem to invalidate modules cache entries, which means we could