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[libc++] Make variables in templates inline #115785

Merged
merged 1 commit into from
Nov 13, 2024
Merged

[libc++] Make variables in templates inline #115785

merged 1 commit into from
Nov 13, 2024

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philnik777
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@philnik777 philnik777 commented Nov 11, 2024 •
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The variables are all constexpr, which implies inline. Since they aren't constexpr in C++03 they're also not inline there. Because of that we define them out-of-line currently. Instead we can use the C++17 extension of inline variables, which results in the same weak definitions of the variables but without having all the boilerplate.

@philnik777 philnik777 marked this pull request as ready for review November 12, 2024 16:29
@philnik777 philnik777 requested review from a team as code owners November 12, 2024 16:29
@llvmbot llvmbot added cmake Build system in general and CMake in particular libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi. libc++abi libc++abi C++ Runtime Library. Not libc++. labels Nov 12, 2024
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llvmbot commented Nov 12, 2024 •
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@llvm/pr-subscribers-libcxxabi

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

Changes

Patch is 30.63 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/115785.diff

14 Files Affected:

  • (modified) libcxx/include/__random/discard_block_engine.h (+2-8)
  • (modified) libcxx/include/__random/linear_congruential_engine.h (+4-20)
  • (modified) libcxx/include/__random/mersenne_twister_engine.h (+14-337)
  • (modified) libcxx/include/__random/shuffle_order_engine.h (+1-4)
  • (modified) libcxx/include/__random/subtract_with_carry_engine.h (+4-17)
  • (modified) libcxx/include/__type_traits/integral_constant.h (+1-4)
  • (modified) libcxx/include/any (-2)
  • (modified) libcxx/include/limits (+23-70)
  • (modified) libcxx/include/ratio (+2-8)
  • (modified) libcxx/src/chrono.cpp (+6)
  • (modified) libcxx/src/filesystem/filesystem_clock.cpp (+3)
  • (modified) libcxx/src/filesystem/path.cpp (+3)
  • (modified) libcxxabi/src/cxa_demangle.cpp (-4)
  • (modified) runtimes/cmake/Modules/WarningFlags.cmake (+1)
diff --git a/libcxx/include/__random/discard_block_engine.h b/libcxx/include/__random/discard_block_engine.h
index f319557a573657..45951245a53401 100644
--- a/libcxx/include/__random/discard_block_engine.h
+++ b/libcxx/include/__random/discard_block_engine.h
@@ -43,8 +43,8 @@ class _LIBCPP_TEMPLATE_VIS discard_block_engine {
   typedef typename _Engine::result_type result_type;
 
   // engine characteristics
-  static _LIBCPP_CONSTEXPR const size_t block_size = __p;
-  static _LIBCPP_CONSTEXPR const size_t used_block = __r;
+  static inline _LIBCPP_CONSTEXPR const size_t block_size = __p;
+  static inline _LIBCPP_CONSTEXPR const size_t used_block = __r;
 
 #ifdef _LIBCPP_CXX03_LANG
   static const result_type _Min = _Engine::_Min;
@@ -110,12 +110,6 @@ class _LIBCPP_TEMPLATE_VIS discard_block_engine {
   operator>>(basic_istream<_CharT, _Traits>& __is, discard_block_engine<_Eng, _Pp, _Rp>& __x);
 };
 
-template <class _Engine, size_t __p, size_t __r>
-_LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::block_size;
-
-template <class _Engine, size_t __p, size_t __r>
-_LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::used_block;
-
 template <class _Engine, size_t __p, size_t __r>
 typename discard_block_engine<_Engine, __p, __r>::result_type discard_block_engine<_Engine, __p, __r>::operator()() {
   if (__n_ >= static_cast<int>(__r)) {
diff --git a/libcxx/include/__random/linear_congruential_engine.h b/libcxx/include/__random/linear_congruential_engine.h
index a0afda4945cdcf..a6e63839d3fc16 100644
--- a/libcxx/include/__random/linear_congruential_engine.h
+++ b/libcxx/include/__random/linear_congruential_engine.h
@@ -251,12 +251,12 @@ class _LIBCPP_TEMPLATE_VIS linear_congruential_engine {
   static_assert(_Min < _Max, "linear_congruential_engine invalid parameters");
 
   // engine characteristics
-  static _LIBCPP_CONSTEXPR const result_type multiplier = __a;
-  static _LIBCPP_CONSTEXPR const result_type increment  = __c;
-  static _LIBCPP_CONSTEXPR const result_type modulus    = __m;
+  static inline _LIBCPP_CONSTEXPR const result_type multiplier = __a;
+  static inline _LIBCPP_CONSTEXPR const result_type increment  = __c;
+  static inline _LIBCPP_CONSTEXPR const result_type modulus    = __m;
   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
-  static _LIBCPP_CONSTEXPR const result_type default_seed = 1u;
+  static inline _LIBCPP_CONSTEXPR const result_type default_seed = 1u;
 
   // constructors and seeding functions
 #ifndef _LIBCPP_CXX03_LANG
@@ -318,22 +318,6 @@ class _LIBCPP_TEMPLATE_VIS linear_congruential_engine {
   operator>>(basic_istream<_CharT, _Traits>& __is, linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
 };
 
-template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
-_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
-    linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
-
-template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
-_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
-    linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
-
-template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
-_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
-    linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
-
-template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
-_LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
-    linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
-
 template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
 template <class _Sseq>
 void linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q, integral_constant<unsigned, 1>) {
diff --git a/libcxx/include/__random/mersenne_twister_engine.h b/libcxx/include/__random/mersenne_twister_engine.h
index 9dd87f9ce71a11..a23feffff0c89c 100644
--- a/libcxx/include/__random/mersenne_twister_engine.h
+++ b/libcxx/include/__random/mersenne_twister_engine.h
@@ -166,22 +166,22 @@ class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine {
   static_assert(__f <= _Max, "mersenne_twister_engine invalid parameters");
 
   // engine characteristics
-  static _LIBCPP_CONSTEXPR const size_t word_size                      = __w;
-  static _LIBCPP_CONSTEXPR const size_t state_size                     = __n;
-  static _LIBCPP_CONSTEXPR const size_t shift_size                     = __m;
-  static _LIBCPP_CONSTEXPR const size_t mask_bits                      = __r;
-  static _LIBCPP_CONSTEXPR const result_type xor_mask                  = __a;
-  static _LIBCPP_CONSTEXPR const size_t tempering_u                    = __u;
-  static _LIBCPP_CONSTEXPR const result_type tempering_d               = __d;
-  static _LIBCPP_CONSTEXPR const size_t tempering_s                    = __s;
-  static _LIBCPP_CONSTEXPR const result_type tempering_b               = __b;
-  static _LIBCPP_CONSTEXPR const size_t tempering_t                    = __t;
-  static _LIBCPP_CONSTEXPR const result_type tempering_c               = __c;
-  static _LIBCPP_CONSTEXPR const size_t tempering_l                    = __l;
-  static _LIBCPP_CONSTEXPR const result_type initialization_multiplier = __f;
+  static inline _LIBCPP_CONSTEXPR const size_t word_size                      = __w;
+  static inline _LIBCPP_CONSTEXPR const size_t state_size                     = __n;
+  static inline _LIBCPP_CONSTEXPR const size_t shift_size                     = __m;
+  static inline _LIBCPP_CONSTEXPR const size_t mask_bits                      = __r;
+  static inline _LIBCPP_CONSTEXPR const result_type xor_mask                  = __a;
+  static inline _LIBCPP_CONSTEXPR const size_t tempering_u                    = __u;
+  static inline _LIBCPP_CONSTEXPR const result_type tempering_d               = __d;
+  static inline _LIBCPP_CONSTEXPR const size_t tempering_s                    = __s;
+  static inline _LIBCPP_CONSTEXPR const result_type tempering_b               = __b;
+  static inline _LIBCPP_CONSTEXPR const size_t tempering_t                    = __t;
+  static inline _LIBCPP_CONSTEXPR const result_type tempering_c               = __c;
+  static inline _LIBCPP_CONSTEXPR const size_t tempering_l                    = __l;
+  static inline _LIBCPP_CONSTEXPR const result_type initialization_multiplier = __f;
   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
-  static _LIBCPP_CONSTEXPR const result_type default_seed = 5489u;
+  static inline _LIBCPP_CONSTEXPR const result_type default_seed = 5489u;
 
   // constructors and seeding functions
 #ifndef _LIBCPP_CXX03_LANG
@@ -310,329 +310,6 @@ class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine {
   }
 };
 
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::word_size;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::state_size;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::shift_size;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::mask_bits;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const typename mersenne_twister_engine<
-    _UIntType,
-    __w,
-    __n,
-    __m,
-    __r,
-    __a,
-    __u,
-    __d,
-    __s,
-    __b,
-    __t,
-    __c,
-    __l,
-    __f>::result_type
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::xor_mask;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_u;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const typename mersenne_twister_engine<
-    _UIntType,
-    __w,
-    __n,
-    __m,
-    __r,
-    __a,
-    __u,
-    __d,
-    __s,
-    __b,
-    __t,
-    __c,
-    __l,
-    __f>::result_type
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_d;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_s;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const typename mersenne_twister_engine<
-    _UIntType,
-    __w,
-    __n,
-    __m,
-    __r,
-    __a,
-    __u,
-    __d,
-    __s,
-    __b,
-    __t,
-    __c,
-    __l,
-    __f>::result_type
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_b;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_t;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const typename mersenne_twister_engine<
-    _UIntType,
-    __w,
-    __n,
-    __m,
-    __r,
-    __a,
-    __u,
-    __d,
-    __s,
-    __b,
-    __t,
-    __c,
-    __l,
-    __f>::result_type
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_c;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const size_t
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_l;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const typename mersenne_twister_engine<
-    _UIntType,
-    __w,
-    __n,
-    __m,
-    __r,
-    __a,
-    __u,
-    __d,
-    __s,
-    __b,
-    __t,
-    __c,
-    __l,
-    __f>::result_type
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::
-        initialization_multiplier;
-
-template <class _UIntType,
-          size_t __w,
-          size_t __n,
-          size_t __m,
-          size_t __r,
-          _UIntType __a,
-          size_t __u,
-          _UIntType __d,
-          size_t __s,
-          _UIntType __b,
-          size_t __t,
-          _UIntType __c,
-          size_t __l,
-          _UIntType __f>
-_LIBCPP_CONSTEXPR const typename mersenne_twister_engine<
-    _UIntType,
-    __w,
-    __n,
-    __m,
-    __r,
-    __a,
-    __u,
-    __d,
-    __s,
-    __b,
-    __t,
-    __c,
-    __l,
-    __f>::result_type
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::default_seed;
-
 template <class _UIntType,
           size_t __w,
           size_t __n,
diff --git a/libcxx/include/__random/shuffle_order_engine.h b/libcxx/include/__random/shuffle_order_engine.h
index 53f6c08971105e..11a46689a0fa67 100644
--- a/libcxx/include/__random/shuffle_order_engine.h
+++ b/libcxx/include/__random/shuffle_order_engine.h
@@ -66,7 +66,7 @@ class _LIBCPP_TEMPLATE_VIS shuffle_order_engine {
 
 public:
   // engine characteristics
-  static _LIBCPP_CONSTEXPR const size_t table_size = __k;
+  static inline _LIBCPP_CONSTEXPR const size_t table_size = __k;
 
 #ifdef _LIBCPP_CXX03_LANG
   static const result_type _Min = _Engine::_Min;
@@ -173,9 +173,6 @@ class _LIBCPP_TEMPLATE_VIS shuffle_order_engine {
   }
 };
 
-template <class _Engine, size_t __k>
-_LIBCPP_CONSTEXPR const size_t shuffle_order_engine<_Engine, __k>::table_size;
-
 template <class _Eng, size_t _Kp>
 _LIBCPP_HIDE_FROM_ABI bool
 operator==(const shuffle_order_engine<_Eng, _Kp>& __x, const shuffle_order_engine<_Eng, _Kp>& __y) {
diff --git a/libcxx/include/__random/subtract_with_carry_engine.h b/libcxx/include/__random/subtract_with_carry_engine.h
index e087ab4a3c2c7b..40dfaf4016ada0 100644
--- a/libcxx/include/__random/subtract_with_carry_engine.h
+++ b/libcxx/include/__random/subtract_with_carry_engine.h
@@ -72,12 +72,12 @@ class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine {
   static_assert(_Min < _Max, "subtract_with_carry_engine invalid parameters");
 
   // engine characteristics
-  static _LIBCPP_CONSTEXPR const size_t word_size = __w;
-  static _LIBCPP_CONSTEXPR const size_t short_lag = __s;
-  static _LIBCPP_CONSTEXPR const size_t long_lag  = __r;
+  static inline _LIBCPP_CONSTEXPR const size_t word_size = __w;
+  static inline _LIBCPP_CONSTEXPR const size_t short_lag = __s;
+  static inline _LIBCPP_CONSTEXPR const size_t long_lag  = __r;
   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
   _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
-  static _LIBCPP_CONSTEXPR const result_type default_seed = 19780503u;
+  static inline _LIBCPP_CONSTEXPR const result_type default_seed = 19780503u;
 
   // constructors and seeding functions
 #ifndef _LIBCPP_CXX03_LANG
@@ -130,19 +130,6 @@ class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine {
   _LIBCPP_HIDE_FROM_ABI void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
 };
 
-template <class _UIntType, size_t __w, size_t __s, size_t __r>
-_LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::word_size;
-
-template <class _UIntType, size_t __w, size_t __s, size_t __r>
-_LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::short_lag;
-
-template <class _UIntType, size_t __w, size_t __s, size_t __r>
-_LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::long_lag;
-
-template <class _UIntType, size_t __w, size_t __s, size_t __r>
-_LIBCPP_CONSTEXPR const typename subtract_with_carry_engine<_UIntType, __w, __s, __r>::result_type
-    subtract_with_carry_engine<_UIntType, __w, __s, __r>::default_seed;
-
 template <class _UIntType, size_t __w, size_t __s, size_t __r>
 void subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd, integral_constant<unsigned, 1>) {
   linear_congruential_engine<result_type, 40014u, 0u, 2147483563u> __e(__sd == 0u ? default_seed : __sd);
diff --git a/libcxx/include/__type_traits/integral_constant.h b/libcxx/include/__type_traits/integral_constant.h
index 23e87e27feff55..b8c75c546aa942 100644
--- a/libcxx/include/__type_traits/integral_constant.h
+++ b/libcxx/include/__type_traits/integral_constant.h
@@ -19,7 +19,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Tp, _Tp __v>
 struct _LIBCPP_TEMPLATE_VIS integral_constant {
-  static _LIBCPP_CONSTEXPR const _Tp value = __v;
+  static inline _LIBCPP_CONSTEXPR const _Tp value = __v;
   typedef _Tp value_type;
   typedef integral_constant type;
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR operator value_type() const _NOEXCEPT { return value; }
@@ -28,9 +28,6 @@ struct _LIBCPP_TEMPLATE_VIS integral_constant {
 #endif
 };
 
-template <class _Tp, _Tp __v>
-_LIBCPP_CONSTEXPR const _Tp integral_constant<_Tp, __v>::value;
-
 typedef integral_constant<bool, true> true_type;
 typedef integral_constant<bool, false> false_type;
 
diff --git a/libcxx/include/any b/libcxx/include/any
index 719dc2cf999e50..cae56fa376e057 100644
--- a/libcxx/include/any
+++ b/libcxx/include/any
@@ -166,8 +166,6 @@ template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS __unique_typeinfo {
   static constexpr int __id = 0;
 };
-template <class _Tp>
-constexpr int __unique_typeinfo<_Tp>::__id;
 
 template <class _Tp>
 inline _LIBCPP_HIDE_FROM_ABI constexpr const void* __get_fallback_typeid() {
diff --git a/libcxx/include/limits b/libcxx/include/limits
index b85c66257d27b7..da0a92d7daff4a 100644
--- a/libcxx/include/limits
+++ b/libcxx/include/limits
@@ -464,18 +464,18 @@ class _LIBCPP_TEMPLATE_VIS numeric_limits : private __libcpp_numeric_limits<_Tp>
   typedef typename __base::type type;
 
 public:
-  static _LIBCPP_CONSTEXPR const bool is_specialized = __base::is_specialized;
+  static inline _LIBCPP_CONSTEXPR const bool is_specialized = __base::is_specialized;
   [[__nodiscard__]] _LI...
[truncated]

ldionne
ldionne reviewed Nov 12, 2024
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Can you provide a bit more context around this change? These variables are not marked inline in the spec AFAICT. Is this just to allow defining them inside the classes and avoiding a bunch of verbose declarations?

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Can you provide a bit more context around this change? These variables are not marked inline in the spec AFAICT. Is this just to allow defining them inside the classes and avoiding a bunch of verbose declarations?

The variables are all constexpr, which implies inline. Since they aren't constexpr in C++03 they're also not inline there. Because of that we define them out-of-line currently. Instead we can use the C++17 (?) extension of inline variables, which results in the same weak definitions of the variables but without having all the boilerplate.

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ldionne commented Nov 12, 2024

Can you provide a bit more context around this change? These variables are not marked inline in the spec AFAICT. Is this just to allow defining them inside the classes and avoiding a bunch of verbose declarations?

The variables are all constexpr, which implies inline.

That is the one thing I forget the most in all of C++. Every time I come across it, I fail to remember that constexpr implies inline -- that's really not natural for me.

LGTM.

@philnik777 philnik777 merged commit b69ddbc into llvm:main Nov 13, 2024
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@philnik777 philnik777 deleted the use_inline_variables branch November 13, 2024 10:57
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cmake Build system in general and CMake in particular libc++abi libc++abi C++ Runtime Library. Not libc++. libc++ libc++ C++ Standard Library. Not GNU libstdc++. Not libc++abi.
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