[cfe-commits] [libcxx] r153968 - in /libcxx/trunk: include/utility src/utility.cpp

[Howard Hinnant]

On Apr 3, 2012, at 5:52 PM, Eli Friedman wrote:

> On Tue, Apr 3, 2012 at 2:09 PM, Howard Hinnant <hhinnant at apple.com> wrote:
>> Author: hhinnant
>> Date: Tue Apr  3 16:09:48 2012
>> New Revision: 153968
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=153968&view=rev
>> Log:
>> constexpr support for <utility>.  Patch contributed by Jonathan Sauer.
>> 
>> Modified:
>>    libcxx/trunk/include/utility
>>    libcxx/trunk/src/utility.cpp
>> 
>> Modified: libcxx/trunk/include/utility
>> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/utility?rev=153968&r1=153967&r2=153968&view=diff
>> ==============================================================================
>> --- libcxx/trunk/include/utility (original)
>> +++ libcxx/trunk/include/utility Tue Apr  3 16:09:48 2012
>> @@ -206,8 +206,11 @@
>>  }
>> 
>>  struct _LIBCPP_VISIBLE piecewise_construct_t { };
>> -//constexpr
>> +#ifdef _LIBCPP_HAS_NO_CONSTEXPR
>>  extern const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
>> +#else
>> +constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
>> +#endif
>> 
>>  template <class _T1, class _T2>
>>  struct _LIBCPP_VISIBLE pair
>> @@ -221,7 +224,7 @@
>>     // pair(const pair&) = default;
>>     // pair(pair&&) = default;
>> 
>> -    _LIBCPP_INLINE_VISIBILITY pair() : first(), second() {}
>> +    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR pair() : first(), second() {}
>> 
>>     _LIBCPP_INLINE_VISIBILITY pair(const _T1& __x, const _T2& __y)
>>         : first(__x), second(__y) {}
>> 
>> Modified: libcxx/trunk/src/utility.cpp
>> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/src/utility.cpp?rev=153968&r1=153967&r2=153968&view=diff
>> ==============================================================================
>> --- libcxx/trunk/src/utility.cpp (original)
>> +++ libcxx/trunk/src/utility.cpp Tue Apr  3 16:09:48 2012
>> @@ -11,6 +11,8 @@
>> 
>>  _LIBCPP_BEGIN_NAMESPACE_STD
>> 
>> +#ifdef _LIBCPP_HAS_NO_CONSTEXPR
>>  const piecewise_construct_t piecewise_construct = {};
>> +#endif
>> 
>>  _LIBCPP_END_NAMESPACE_STD
> 
> This seems dangerous: we don't want the ABI of libc++ to depend on
> _LIBCPP_HAS_NO_CONSTEXPR.
> 
> -Eli

Agreed.  I have not yet built a constexpr enabled clang.  Once I do I will investigate the best way to handle this.

Howard