libstdc++: Enable std::bitset<N>::bitset(const char*) for freestanding

The std::bitset constructor from a character string is specified in
terms of std::basic_string and std::char_traits, but doesn't need to be.
This makes it available for freestanding.

libstdc++-v3/ChangeLog:

	* include/std/bitset (bitset(const C*, size_type n, C, C))
	[!_GLIBCXX_HOSTED]: Remove std::basic_string dependency.
	(_M_copy_from_ptr) [!_GLIBCXX_HOSTED]: Abort instead of
	throwing.

diff --git a/libstdc++-v3/include/std/bitset b/libstdc++-v3/include/std/bitset
index 10fb05a1b9027e49e0d925f2ca4623bad836768c..afabeb4ba019e4092b06d74a73ba8426d3f60497 100644 (file)
--- a/libstdc++-v3/include/std/bitset
+++ b/libstdc++-v3/include/std/bitset
@@ -697,7 +697,38 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       _S_do_sanitize_val(unsigned long long __val)
       { return __val & ~((~static_cast<unsigned long long>(0)) << _Nb); }
     };
-#endif
+
+  namespace __bitset
+  {
+#if _GLIBCXX_HOSTED
+    template<typename _CharT>
+      using __string = std::basic_string<_CharT>;
+#else
+    template<typename _CharT>
+      struct __string
+      {
+       using size_type = size_t;
+       static constexpr size_type npos = size_type(-1);
+
+       struct traits_type
+       {
+         static _GLIBCXX14_CONSTEXPR size_t
+         length(const _CharT* __s) noexcept
+         {
+           size_t __n = 0;
+           while (__s[__n])
+             __n++;
+           return __n;
+         }
+
+         static constexpr bool
+         eq(_CharT __l, _CharT __r) noexcept
+         { return __l == __r; }
+       };
+      };
+#endif // HOSTED
+  } // namespace __bitset
+#endif // C++11
 
   /**
    *  @brief The %bitset class represents a @e fixed-size sequence of bits.
@@ -963,6 +994,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
          _M_check_initial_position(__s, __position);
          _M_copy_from_string(__s, __position, __n, __zero, __one);
        }
+#endif // HOSTED
 
 #if __cplusplus >= 201103L
       /**
@@ -978,23 +1010,23 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
        [[__gnu__::__nonnull__]]
        _GLIBCXX23_CONSTEXPR
         explicit
-        bitset(const _CharT* __str,
-              typename std::basic_string<_CharT>::size_type __n
-              = std::basic_string<_CharT>::npos,
+       bitset(const _CharT* __str,
+              typename __bitset::__string<_CharT>::size_type __n
+                = __bitset::__string<_CharT>::npos,
               _CharT __zero = _CharT('0'), _CharT __one = _CharT('1'))
         : _Base()
         {
+#if _GLIBCXX_HOSTED
          if (!__str)
            __throw_logic_error(__N("bitset::bitset(const _CharT*, ...)"));
+#endif
+         using _Traits = typename __bitset::__string<_CharT>::traits_type;
 
-         if (__n == std::basic_string<_CharT>::npos)
-           __n = std::char_traits<_CharT>::length(__str);
-         _M_copy_from_ptr<_CharT, std::char_traits<_CharT>>(__str, __n, 0,
-                                                            __n, __zero,
-                                                            __one);
+         if (__n == __bitset::__string<_CharT>::npos)
+           __n = _Traits::length(__str);
+         _M_copy_from_ptr<_CharT, _Traits>(__str, __n, 0, __n, __zero, __one);
        }
 #endif // C++11
-#endif // HOSTED
 
       // 23.3.5.2 bitset operations:
       ///@{
@@ -1463,7 +1495,6 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 #endif
     };
 
-#if _GLIBCXX_HOSTED
   // Definitions of non-inline member functions.
   template<size_t _Nb>
     template<class _CharT, class _Traits>
@@ -1483,10 +1514,17 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
            else if (_Traits::eq(__c, __one))
              _Unchecked_set(__i - 1);
            else
-             __throw_invalid_argument(__N("bitset::_M_copy_from_ptr"));
+             {
+#if _GLIBCXX_HOSTED
+               __throw_invalid_argument(__N("bitset::_M_copy_from_ptr"));
+#else
+               __builtin_abort();
+#endif
+             }
          }
       }
 
+#if _GLIBCXX_HOSTED
   template<size_t _Nb>
     template<class _CharT, class _Traits, class _Alloc>
       _GLIBCXX23_CONSTEXPR