Author: ericwf
Date: Mon Jan 16 15:15:08 2017
New Revision: 292159
URL: http://llvm.org/viewvc/llvm-project?rev=292159&view=rev
Log:
Fix std::tuples EBO when targeting the MSVC ABI.
MSVC/clang-cl doesn't do a full EBO unless __declspec(empty_bases)
is applied to the derived type. This causes certain tuple tests
to fail.
This patch adds the empty_bases attribute to __tuple_impl in order
for tuple to fully provide the EBO.
Modified:
libcxx/trunk/include/__config
libcxx/trunk/include/tuple
Modified: libcxx/trunk/include/__config
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/__config?rev=292159&r1=292158&r2=292159&view=diff
==============================================================================
--- libcxx/trunk/include/__config (original)
+++ libcxx/trunk/include/__config Mon Jan 16 15:15:08 2017
@@ -100,6 +100,9 @@
#ifndef __is_identifier
#define __is_identifier(__x) 1
#endif
+#ifndef __has_declspec_attribute
+#define __has_declspec_attribute(__x) 0
+#endif
#define __has_keyword(__x) !(__is_identifier(__x))
@@ -1023,6 +1026,13 @@ _LIBCPP_FUNC_VIS extern "C" void __sanit
# define _LIBCPP_DIAGNOSE_ERROR(...)
#endif
+#if defined(_LIBCPP_ABI_MICROSOFT) && \
+ (defined(_LIBCPP_COMPILER_MSVC) || __has_declspec_attribute(empty_bases))
+# define _LIBCPP_DECLSPEC_EMPTY_BASES __declspec(empty_bases)
+#else
+# define _LIBCPP_DECLSPEC_EMPTY_BASES
+#endif
+
#endif // __cplusplus
#endif // _LIBCPP_CONFIG
Modified: libcxx/trunk/include/tuple
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/tuple?rev=292159&r1=292158&r2=292159&view=diff
==============================================================================
--- libcxx/trunk/include/tuple (original)
+++ libcxx/trunk/include/tuple Mon Jan 16 15:15:08 2017
@@ -366,7 +366,7 @@ struct __all_default_constructible<__tup
template<class _Indx, class ..._Tp> struct __tuple_impl;
template<size_t ..._Indx, class ..._Tp>
-struct __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
+struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>,
_Tp...>
: public __tuple_leaf<_Indx, _Tp>...
{
_LIBCPP_INLINE_VISIBILITY
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