generic-library/cxx
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Fix some places where we could call memmove(null,xxx,0) - which is UB

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@238831 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Marshall Clow 2015-06-02 13:52:16 +00:00
parent 56523ff60e
commit 708b86b5f9
1 changed files with 14 additions and 6 deletions
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20
include/algorithm
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@ -1763,7 +1763,8 @@ typename enable_if
__copy(_Tp* __first, _Tp* __last, _Up* __result) __copy(_Tp* __first, _Tp* __last, _Up* __result)
{ {
const size_t __n = static_cast<size_t>(__last - __first); const size_t __n = static_cast<size_t>(__last - __first);
_VSTD::memmove(__result, __first, __n * sizeof(_Up)); if (__n > 0)
_VSTD::memmove(__result, __first, __n * sizeof(_Up));
return __result + __n; return __result + __n;
} }
@ -1798,8 +1799,11 @@ typename enable_if
__copy_backward(_Tp* __first, _Tp* __last, _Up* __result) __copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
{ {
const size_t __n = static_cast<size_t>(__last - __first); const size_t __n = static_cast<size_t>(__last - __first);
__result -= __n; if (__n > 0)
_VSTD::memmove(__result, __first, __n * sizeof(_Up)); {
__result -= __n;
_VSTD::memmove(__result, __first, __n * sizeof(_Up));
}
return __result; return __result;
} }
@ -1896,7 +1900,8 @@ typename enable_if
__move(_Tp* __first, _Tp* __last, _Up* __result) __move(_Tp* __first, _Tp* __last, _Up* __result)
{ {
const size_t __n = static_cast<size_t>(__last - __first); const size_t __n = static_cast<size_t>(__last - __first);
_VSTD::memmove(__result, __first, __n * sizeof(_Up)); if (__n > 0)
_VSTD::memmove(__result, __first, __n * sizeof(_Up));
return __result + __n; return __result + __n;
} }
@ -1931,8 +1936,11 @@ typename enable_if
__move_backward(_Tp* __first, _Tp* __last, _Up* __result) __move_backward(_Tp* __first, _Tp* __last, _Up* __result)
{ {
const size_t __n = static_cast<size_t>(__last - __first); const size_t __n = static_cast<size_t>(__last - __first);
__result -= __n; if (__n > 0)
_VSTD::memmove(__result, __first, __n * sizeof(_Up)); {
__result -= __n;
_VSTD::memmove(__result, __first, __n * sizeof(_Up));
}
return __result; return __result;
} }