Workaround compilers w/o C++1z inline variables

llvm-svn: 287255

diff --git a/libcxx/include/__config b/libcxx/include/__config
index e9d3e5f..a8603be 100644 (file)
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -796,6 +796,11 @@ template <unsigned> struct __static_assert_check {};
 #define _LIBCPP_CONSTEXPR_AFTER_CXX14
 #endif
 
+// FIXME: Remove all usages of this macro once compilers catch up.
+#if !defined(__cpp_inline_variables) || (__cpp_inline_variables < 201606L)
+# define _LIBCPP_HAS_NO_INLINE_VARIABLES
+#endif
+
 #ifdef _LIBCPP_HAS_NO_RVALUE_REFERENCES
 #  define _LIBCPP_EXPLICIT_MOVE(x) _VSTD::move(x)
 #else

diff --git a/libcxx/include/utility b/libcxx/include/utility
index 52c062d..3642214 100644 (file)
--- a/libcxx/include/utility
+++ b/libcxx/include/utility
@@ -897,21 +897,30 @@ _T1 exchange(_T1& __obj, _T2 && __new_value)
 struct _LIBCPP_TYPE_VIS in_place_t {
     explicit in_place_t() = default;
 };
-inline constexpr in_place_t in_place{};
+#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
+inline
+#endif
+constexpr in_place_t in_place{};
 
 template <class _Tp>
 struct _LIBCPP_TYPE_VIS in_place_type_t {
     explicit in_place_type_t() = default;
 };
 template <class _Tp>
-inline constexpr in_place_type_t<_Tp> in_place_type{};
+#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
+inline
+#endif
+constexpr in_place_type_t<_Tp> in_place_type{};
 
 template <size_t _Idx>
 struct _LIBCPP_TYPE_VIS in_place_index_t {
     explicit in_place_index_t() = default;
 };
 template <size_t _Idx>
-inline constexpr in_place_index_t<_Idx> in_place_index{};
+#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
+inline
+#endif
+constexpr in_place_index_t<_Idx> in_place_index{};
 
 template <class _Tp> struct __is_inplace_type_imp : false_type {};
 template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};