Don't try to memcpy zero bytes; sometimes the source pointer is NULL, and that's UB. Thanks to Nuno Lopes for the catch.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@238666 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Marshall Clow 2015-05-31 03:13:31 +00:00
parent 0620fc865b
commit bf0460e0a0

View File

@ -621,6 +621,8 @@ void* align(size_t alignment, size_t size, void*& ptr, size_t& space);
#pragma GCC system_header
#endif
extern "C" int printf(const char * __restrict, ...);
_LIBCPP_BEGIN_NAMESPACE_STD
// addressof moved to <__functional_base>
@ -1521,7 +1523,8 @@ struct _LIBCPP_TYPE_VIS_ONLY allocator_traits
__construct_forward(allocator_type& __a, _Tp* __begin1, _Tp* __end1, _Tp*& __begin2)
{
ptrdiff_t _Np = __end1 - __begin1;
_VSTD::memcpy(__begin2, __begin1, _Np * sizeof(_Tp));
if (_Np > 0)
_VSTD::memcpy(__begin2, __begin1, _Np * sizeof(_Tp));
__begin2 += _Np;
}
@ -1549,7 +1552,8 @@ struct _LIBCPP_TYPE_VIS_ONLY allocator_traits
{
typedef typename remove_const<_Tp>::type _Vp;
ptrdiff_t _Np = __end1 - __begin1;
_VSTD::memcpy(const_cast<_Vp*>(__begin2), __begin1, _Np * sizeof(_Tp));
if (_Np > 0)
_VSTD::memcpy(const_cast<_Vp*>(__begin2), __begin1, _Np * sizeof(_Tp));
__begin2 += _Np;
}
@ -1580,7 +1584,8 @@ struct _LIBCPP_TYPE_VIS_ONLY allocator_traits
{
ptrdiff_t _Np = __end1 - __begin1;
__end2 -= _Np;
_VSTD::memcpy(__end2, __begin1, _Np * sizeof(_Tp));
if (_Np > 0)
_VSTD::memcpy(__end2, __begin1, _Np * sizeof(_Tp));
}
private: