[libcxx] Use __decltype instead of __typeof__

Summary:
Both clang and GCC provide C++11 decltype semantics as __decltype in c++03 mode. We should use this instead of __typeof__ when availble. 

GCC added __decltype in 4.6.0, and AFAIK clang provided __decltype ever since 3.3. Unfortunately `__has_builtin(__decltype)` doesn't work for clang so we need to check the compiler version instead.


Reviewers: mclow.lists

Reviewed By: mclow.lists

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D10426

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@239662 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier 2015-06-13 06:27:17 +00:00
parent b7fc49f828
commit 6d7a2cb57d

View File

@ -577,7 +577,22 @@ template <unsigned> struct __static_assert_check {};
#endif // _LIBCPP_HAS_NO_STATIC_ASSERT
#ifdef _LIBCPP_HAS_NO_DECLTYPE
#define decltype(x) __typeof__(x)
# if defined(__clang__)
# define _CLANG_VER (__clang_major__ * 100 + __clang_minor__)
# else
# define _CLANG_VER 0
# endif
// Clang 3.0 and GCC 4.6 provide __decltype in all standard modes.
// XCode 5.0 is based off of Clang 3.3 SVN. We require Clang 3.3
// be sure we have __decltype.
#if (defined(__apple_build_version__) && _CLANG_VER >= 500) || \
(!defined(__apple_build_version__) && _CLANG_VER >= 303) || \
_GNUC_VER >= 406
# define decltype(__x) __decltype(__x)
#else
# define decltype(__x) __typeof__(__x)
#endif
#undef _CLANG_VER
#endif
#ifdef _LIBCPP_HAS_NO_CONSTEXPR