[libcxx] Avoid spurious construction of valarray elements
Summary:
Currently libc++ implements some operations on valarray by using the
resize method. This method has a parameter with a default value.
Because of this, valarray may spuriously construct and destruct
objects of valarray's element type.
This patch fixes this issue and adds corresponding test cases.
Reviewers: EricWF, mclow.lists
Reviewed By: mclow.lists
Subscribers: rogfer01, cfe-commits
Differential Revision: https://reviews.llvm.org/D41992
llvm-svn: 324596
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 2b20304def44a0e3c4ab4ae90f50d4c4449ce03d
diff --git a/include/valarray b/include/valarray
index ee61238..b495ccf 100644
--- a/include/valarray
+++ b/include/valarray
@@ -1053,6 +1053,9 @@
friend
const _Up*
end(const valarray<_Up>& __v);
+
+ void __clear();
+ valarray& __assign_range(const value_type* __f, const value_type* __l);
};
_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS valarray<size_t>::valarray(size_t))
@@ -2750,7 +2753,24 @@
: __begin_(0),
__end_(0)
{
- resize(__n);
+ if (__n)
+ {
+ __begin_ = __end_ = static_cast<value_type*>(_VSTD::__allocate(__n * sizeof(value_type)));
+#ifndef _LIBCPP_NO_EXCEPTIONS
+ try
+ {
+#endif // _LIBCPP_NO_EXCEPTIONS
+ for (; __n; --__n, ++__end_)
+ ::new (__end_) value_type();
+#ifndef _LIBCPP_NO_EXCEPTIONS
+ }
+ catch (...)
+ {
+ __clear();
+ throw;
+ }
+#endif // _LIBCPP_NO_EXCEPTIONS
+ }
}
template <class _Tp>
@@ -2780,7 +2800,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
@@ -2805,7 +2825,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
@@ -2842,7 +2862,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
@@ -2870,7 +2890,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
@@ -2899,7 +2919,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
@@ -2928,7 +2948,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
@@ -2957,7 +2977,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
@@ -2968,7 +2988,24 @@
inline
valarray<_Tp>::~valarray()
{
- resize(0);
+ __clear();
+}
+
+template <class _Tp>
+valarray<_Tp>&
+valarray<_Tp>::__assign_range(const value_type* __f, const value_type* __l)
+{
+ size_t __n = __l - __f;
+ if (size() != __n)
+ {
+ __clear();
+ __begin_ = static_cast<value_type*>(_VSTD::__allocate(__n * sizeof(value_type)));
+ __end_ = __begin_ + __n;
+ _VSTD::uninitialized_copy(__f, __l, __begin_);
+ } else {
+ _VSTD::copy(__f, __l, __begin_);
+ }
+ return *this;
}
template <class _Tp>
@@ -2976,11 +3013,7 @@
valarray<_Tp>::operator=(const valarray& __v)
{
if (this != &__v)
- {
- if (size() != __v.size())
- resize(__v.size());
- _VSTD::copy(__v.__begin_, __v.__end_, __begin_);
- }
+ return __assign_range(__v.__begin_, __v.__end_);
return *this;
}
@@ -2991,7 +3024,7 @@
valarray<_Tp>&
valarray<_Tp>::operator=(valarray&& __v) _NOEXCEPT
{
- resize(0);
+ __clear();
__begin_ = __v.__begin_;
__end_ = __v.__end_;
__v.__begin_ = nullptr;
@@ -3004,10 +3037,7 @@
valarray<_Tp>&
valarray<_Tp>::operator=(initializer_list<value_type> __il)
{
- if (size() != __il.size())
- resize(__il.size());
- _VSTD::copy(__il.begin(), __il.end(), __begin_);
- return *this;
+ return __assign_range(__il.begin(), __il.end());
}
#endif // _LIBCPP_CXX03_LANG
@@ -3680,7 +3710,7 @@
template <class _Tp>
void
-valarray<_Tp>::resize(size_t __n, value_type __x)
+valarray<_Tp>::__clear()
{
if (__begin_ != nullptr)
{
@@ -3689,6 +3719,13 @@
_VSTD::__libcpp_deallocate(__begin_);
__begin_ = __end_ = nullptr;
}
+}
+
+template <class _Tp>
+void
+valarray<_Tp>::resize(size_t __n, value_type __x)
+{
+ __clear();
if (__n)
{
__begin_ = __end_ = static_cast<value_type*>(_VSTD::__allocate(__n * sizeof(value_type)));
@@ -3702,7 +3739,7 @@
}
catch (...)
{
- resize(0);
+ __clear();
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS