LWG 2145 - mark constructor for std::error_category as inline and constexpr. Leave the (existing, out-of-line, non-constexpr) in the dylib for compatibility with existing programs)

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@188858 91177308-0d34-0410-b5e6-96231b3b80d8

include/system_error

@@ -22,6 +22,7 @@ class error_category
 public:
     virtual ~error_category() noexcept;
 
+    constexpr error_category();
     error_category(const error_category&) = delete;
     error_category& operator=(const error_category&) = delete;
 
@@ -366,7 +367,11 @@ class _LIBCPP_TYPE_VIS error_category
 public:
     virtual ~error_category() _NOEXCEPT;
 
+#ifdef _LIBCPP_BUILDING_SYSTEM_ERROR
     error_category() _NOEXCEPT;
+#else
+    _LIBCPP_ALWAYS_INLINE _LIBCPP_CONSTEXPR_AFTER_CXX11 error_category() _NOEXCEPT {}
+#endif
 private:
     error_category(const error_category&);// = delete;
     error_category& operator=(const error_category&);// = delete;

src/system_error.cpp

@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#define	_LIBCPP_BUILDING_SYSTEM_ERROR
 #include "system_error"
 #include "string"
 #include "cstring"

www/cxx1y_status.html

@@ -143,7 +143,7 @@
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2094">2094</a></td><td>duration conversion overflow shouldn't participate in overload resolution</td><td>Bristol</td><td></td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2122">2122</a></td><td>merge() stability for lists versus forward lists</td><td>Bristol</td><td></td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2128">2128</a></td><td>Absence of global functions cbegin/cend</td><td>Bristol</td><td></td></tr>
-	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2145">2145</a></td><td>error_category default constructor</td><td>Bristol</td><td></td></tr>
+	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2145">2145</a></td><td>error_category default constructor</td><td>Bristol</td><td>Complete</td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2147">2147</a></td><td>Unclear hint type in Allocator's allocate function</td><td>Bristol</td><td></td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148">2148</a></td><td>Hashing enums should be supported directly by std::hash</td><td>Bristol</td><td></td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2149">2149</a></td><td>Concerns about 20.8/5</td><td>Bristol</td><td></td></tr>