[PATCH] D41048: [libcxx] workaround PR 28385 in __find_exactly_one_checked

[Casey Carter via Phabricator via cfe-commits]

CaseyCarter updated this revision to Diff 126297.
CaseyCarter added a comment.

Hide the ugly version test in `<__config>`, define a slightly-more-meaningful macro `_LIBCPP_WORKAROUND_CLANG_28385`.


https://reviews.llvm.org/D41048

Files:
  include/__config
  include/tuple


Index: include/tuple
===================================================================
--- include/tuple
+++ include/tuple
@@ -1012,10 +1012,20 @@
 
 template <class _T1, class ..._Args>
 struct __find_exactly_one_checked {
-  static constexpr bool __matches[] = {is_same<_T1, _Args>::value...};
+#if defined(_LIBCPP_WORKAROUND_CLANG_28385) && _LIBCPP_WORKAROUND_CLANG_28385
+    inline _LIBCPP_INLINE_VISIBILITY
+    static constexpr size_t __index()
+    {
+        constexpr bool __matches[] = {is_same<_T1, _Args>::value...};
+        return __find_detail::__find_idx(0, __matches);
+    }
+    static constexpr size_t value = __index();
+#else // _LIBCPP_WORKAROUND_CLANG_28385
+    static constexpr bool __matches[] = {is_same<_T1, _Args>::value...};
     static constexpr size_t value = __find_detail::__find_idx(0, __matches);
-    static_assert (value != __not_found, "type not found in type list" );
-    static_assert(value != __ambiguous,"type occurs more than once in type list");
+#endif // _LIBCPP_WORKAROUND_CLANG_28385
+    static_assert(value != __not_found, "type not found in type list" );
+    static_assert(value != __ambiguous, "type occurs more than once in type list");
 };
 
 template <class _T1>
Index: include/__config
===================================================================
--- include/__config
+++ include/__config
@@ -456,7 +456,7 @@
 // Allow for build-time disabling of unsigned integer sanitization
 #if !defined(_LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK) && __has_attribute(no_sanitize)
 #define _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK __attribute__((__no_sanitize__("unsigned-integer-overflow")))
-#endif 
+#endif
 
 #if __has_builtin(__builtin_launder)
 #define	_LIBCPP_COMPILER_HAS_BUILTIN_LAUNDER
@@ -1273,6 +1273,14 @@
 # endif
 #endif // defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
 
+#ifndef _LIBCPP_WORKAROUND_CLANG_28385
+ #if defined(_LIBCPP_COMPILER_CLANG) && _LIBCPP_CLANG_VER >= 600 && _LIBCPP_STD_VER > 14
+  #define _LIBCPP_WORKAROUND_CLANG_28385 1
+ #else
+  #define _LIBCPP_WORKAROUND_CLANG_28385 0
+ #endif
+#endif
+
 #endif // __cplusplus
 
 #endif // _LIBCPP_CONFIG


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