Fix std::vector's use of temporary objects
* include/bits/stl_vector.h (emplace(const_iterator, _Args&&...)): Define inline. Forward to _M_emplace_aux. (insert(const_iterator, value_type&&)): Forward to _M_insert_rval. (_M_insert_rval, _M_emplace_aux): Declare new functions. (_Temporary_value): New RAII type using allocator to construct/destroy. (_S_insert_aux_assign): Remove. (_M_insert_aux): Make non-variadic. * include/bits/vector.tcc (insert(const_iterator, const value_type&)): Use _Temporary_value. (emplace(const_iterator, _Args&&...)): Remove definition. (_M_insert_rval, _M_emplace_aux): Define. (_M_insert_aux): Make non-variadic, stop using _S_insert_aux_assign. (_M_fill_insert): Use _Temporary_value. * testsuite/23_containers/vector/allocator/construction.cc: New test. * testsuite/23_containers/vector/modifiers/insert_vs_emplace.cc: Adjust expected results for emplacing an lvalue with reallocation. * testsuite/23_containers/vector/check_construct_destroy.cc: Adjust expected results to account for construction/destruction of temporary using allocator. From-SVN: r237985
This commit is contained in:
Jonathan Wakely
Jonathan Wakely
parent
bf7499197f
commit
9958c7eb58
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@ -1,3 +1,26 @@
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2016-07-04 Jonathan Wakely <jwakely@redhat.com>
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* include/bits/stl_vector.h (emplace(const_iterator, _Args&&...)):
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Define inline. Forward to _M_emplace_aux.
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(insert(const_iterator, value_type&&)): Forward to _M_insert_rval.
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(_M_insert_rval, _M_emplace_aux): Declare new functions.
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(_Temporary_value): New RAII type using allocator to construct/destroy.
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(_S_insert_aux_assign): Remove.
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(_M_insert_aux): Make non-variadic.
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* include/bits/vector.tcc (insert(const_iterator, const value_type&)):
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Use _Temporary_value.
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(emplace(const_iterator, _Args&&...)): Remove definition.
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(_M_insert_rval, _M_emplace_aux): Define.
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(_M_insert_aux): Make non-variadic, stop using _S_insert_aux_assign.
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(_M_fill_insert): Use _Temporary_value.
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* testsuite/23_containers/vector/allocator/construction.cc: New test.
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* testsuite/23_containers/vector/modifiers/insert_vs_emplace.cc:
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Adjust expected results for emplacing an lvalue with reallocation.
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* testsuite/23_containers/vector/check_construct_destroy.cc: Adjust
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expected results to account for construction/destruction of temporary
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using allocator.
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* testsuite/backward/hash_set/check_construct_destroy.cc: Likewise.
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2016-07-04 Ville Voutilainen <ville.voutilainen@gmail.com>
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PR libstdc++/71313
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@ -995,7 +995,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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*/
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template<typename... _Args>
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iterator
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emplace(const_iterator __position, _Args&&... __args);
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emplace(const_iterator __position, _Args&&... __args)
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{ return _M_emplace_aux(__position, std::forward<_Args>(__args)...); }
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/**
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* @brief Inserts given value into %vector before specified iterator.
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@ -1040,7 +1041,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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*/
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iterator
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insert(const_iterator __position, value_type&& __x)
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{ return emplace(__position, std::move(__x)); }
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{ return _M_insert_rval(__position, std::move(__x)); }
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/**
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* @brief Inserts an initializer_list into the %vector.
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@ -1431,30 +1432,65 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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_M_shrink_to_fit();
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#endif
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// Called by insert(p,x)
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#if __cplusplus < 201103L
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// Called by insert(p,x)
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void
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_M_insert_aux(iterator __position, const value_type& __x);
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#else
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// A value_type object constructed with _Alloc_traits::construct()
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// and destroyed with _Alloc_traits::destroy().
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struct _Temporary_value
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{
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template<typename... _Args>
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static void
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_S_insert_aux_assign(iterator __pos, _Args&&... __args)
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{ *__pos = _Tp(std::forward<_Args>(__args)...); }
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explicit
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_Temporary_value(vector* __vec, _Args&&... __args) : _M_this(__vec)
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{
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_Alloc_traits::construct(_M_this->_M_impl, _M_ptr(),
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std::forward<_Args>(__args)...);
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}
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static void
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_S_insert_aux_assign(iterator __pos, _Tp&& __arg)
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{ *__pos = std::move(__arg); }
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~_Temporary_value()
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{ _Alloc_traits::destroy(_M_this->_M_impl, _M_ptr()); }
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template<typename... _Args>
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value_type&
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_M_val() { return *reinterpret_cast<_Tp*>(&__buf); }
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private:
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pointer
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_M_ptr() { return pointer_traits<pointer>::pointer_to(_M_val()); }
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vector* _M_this;
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typename aligned_storage<sizeof(_Tp), alignof(_Tp)>::type __buf;
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};
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// Called by insert(p,x) and other functions when insertion needs to
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// reallocate or move existing elements. _Arg is either _Tp& or _Tp.
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template<typename _Arg>
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void
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_M_insert_aux(iterator __position, _Args&&... __args);
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_M_insert_aux(iterator __position, _Arg&& __arg);
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// Either move-construct at the end, or forward to _M_insert_aux.
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iterator
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_M_insert_rval(const_iterator __position, value_type&& __v);
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// Called by push_back(x) and emplace_back(args) when they need to
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// reallocate.
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template<typename... _Args>
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void
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_M_emplace_back_aux(_Args&&... __args);
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// Try to emplace at the end, otherwise forward to _M_insert_aux.
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template<typename... _Args>
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iterator
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_M_emplace_aux(const_iterator __position, _Args&&... __args);
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// Emplacing an rvalue of the correct type can use _M_insert_rval.
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iterator
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_M_emplace_aux(const_iterator __position, value_type&& __v)
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{ return _M_insert_rval(__position, std::move(__v)); }
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#endif
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// Called by the latter.
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// Called by _M_fill_insert, _M_insert_aux etc.
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size_type
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_M_check_len(size_type __n, const char* __s) const
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{
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@ -124,8 +124,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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const auto __pos = begin() + (__position - cbegin());
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if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
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{
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_Tp __x_copy = __x;
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_M_insert_aux(__pos, std::move(__x_copy));
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// __x could be an existing element of this vector, so make a
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// copy of it before _M_insert_aux moves elements around.
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_Temporary_value __x_copy(this, __x);
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_M_insert_aux(__pos, std::move(__x_copy._M_val()));
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}
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else
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_M_insert_aux(__pos, __x);
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@ -297,30 +299,49 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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#if __cplusplus >= 201103L
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template<typename _Tp, typename _Alloc>
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template<typename... _Args>
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typename vector<_Tp, _Alloc>::iterator
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auto
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vector<_Tp, _Alloc>::
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emplace(const_iterator __position, _Args&&... __args)
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_M_insert_rval(const_iterator __position, value_type&& __v) -> iterator
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{
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const size_type __n = __position - begin();
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const auto __n = __position - cbegin();
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if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage
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&& __position == end())
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&& __position == cend())
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{
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_Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
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std::forward<_Args>(__args)...);
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std::move(__v));
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++this->_M_impl._M_finish;
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}
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else
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_M_insert_aux(begin() + (__position - cbegin()),
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std::forward<_Args>(__args)...);
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_M_insert_aux(begin() + __n, std::move(__v));
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return iterator(this->_M_impl._M_start + __n);
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}
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template<typename _Tp, typename _Alloc>
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template<typename... _Args>
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auto
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vector<_Tp, _Alloc>::
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_M_emplace_aux(const_iterator __position, _Args&&... __args)
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-> iterator
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{
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const auto __n = __position - cbegin();
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if (__position == cend())
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emplace_back(std::forward<_Args>(__args)...);
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else
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{
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// We need to construct a temporary because something in __args...
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// could alias one of the elements of the container and so we
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// need to use it before _M_insert_aux moves elements around.
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_Temporary_value __tmp(this, std::forward<_Args>(__args)...);
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_M_insert_aux(begin() + __n, std::move(__tmp._M_val()));
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}
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return iterator(this->_M_impl._M_start + __n);
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}
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template<typename _Tp, typename _Alloc>
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template<typename _Arg>
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void
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vector<_Tp, _Alloc>::
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_M_insert_aux(iterator __position, _Args&&... __args)
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_M_insert_aux(iterator __position, _Arg&& __arg)
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#else
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template<typename _Tp, typename _Alloc>
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void
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@ -343,7 +364,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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#if __cplusplus < 201103L
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*__position = __x_copy;
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#else
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_S_insert_aux_assign(__position, std::forward<_Args>(__args)...);
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*__position = std::forward<_Arg>(__arg);
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#endif
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}
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else
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@ -355,14 +376,15 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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pointer __new_finish(__new_start);
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__try
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{
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// The order of the three operations is dictated by the C++0x
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// The order of the three operations is dictated by the C++11
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// case, where the moves could alter a new element belonging
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// to the existing vector. This is an issue only for callers
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// taking the element by const lvalue ref (see 23.1/13).
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// taking the element by lvalue ref (see last bullet of C++11
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// [res.on.arguments]).
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_Alloc_traits::construct(this->_M_impl,
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__new_start + __elems_before,
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#if __cplusplus >= 201103L
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std::forward<_Args>(__args)...);
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std::forward<_Arg>(__arg));
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#else
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__x);
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#endif
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@ -455,7 +477,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
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if (size_type(this->_M_impl._M_end_of_storage
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- this->_M_impl._M_finish) >= __n)
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{
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#if __cplusplus < 201103L
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value_type __x_copy = __x;
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#else
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_Temporary_value __tmp(this, __x);
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value_type& __x_copy = __tmp._M_val();
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#endif
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const size_type __elems_after = end() - __position;
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pointer __old_finish(this->_M_impl._M_finish);
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if (__elems_after > __n)
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@ -0,0 +1,105 @@
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// Copyright (C) 2016 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING3. If not see
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// <http://www.gnu.org/licenses/>.
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// { dg-options "-std=gnu++11" }
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// { dg-do compile }
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#include <vector>
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struct Tag { };
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template<typename T>
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struct TaggingAllocator
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{
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using value_type = T;
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TaggingAllocator() = default;
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template<typename U>
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TaggingAllocator(const TaggingAllocator<U>&) { }
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T*
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allocate(std::size_t n) { return std::allocator<T>{}.allocate(n); }
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void
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deallocate(T* p, std::size_t n) { std::allocator<T>{}.deallocate(p, n); }
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template<typename U, typename... Args>
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void
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construct(U* p, Args&&... args)
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{ ::new((void*)p) U(Tag{}, std::forward<Args>(args)...); }
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template<typename U, typename... Args>
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void
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destroy(U* p)
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{ p->~U(); }
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};
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template<typename T, typename U>
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bool
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operator==(const TaggingAllocator<T>&, const TaggingAllocator<U>&)
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{ return true; }
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template<typename T, typename U>
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bool
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operator!=(const TaggingAllocator<T>&, const TaggingAllocator<U>&)
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{ return false; }
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struct X
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{
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// All constructors must be passed the Tag type.
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// DefaultInsertable into vector<X, TaggingAllocator<X>>,
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X(Tag) { }
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// CopyInsertable into vector<X, TaggingAllocator<X>>,
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X(Tag, const X&) { }
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// MoveInsertable into vector<X, TaggingAllocator<X>>, and
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X(Tag, X&&) { }
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// EmplaceConstructible into vector<X, TaggingAllocator<X>> from args.
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template<typename... Args>
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X(Tag, Args&&...) { }
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// not DefaultConstructible, CopyConstructible or MoveConstructible.
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X() = delete;
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X(const X&) = delete;
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X(X&&) = delete;
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// CopyAssignable.
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X& operator=(const X&) { return *this; }
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// MoveAssignable.
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X& operator=(X&&) { return *this; }
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private:
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// Not Destructible.
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~X() { }
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// Erasable from vector<X, TaggingAllocator<X>>.
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friend class TaggingAllocator<X>;
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};
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template class std::vector<X, TaggingAllocator<X>>;
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void test01()
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{
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std::vector<X, TaggingAllocator<X>> v;
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v.reserve(3);
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v.emplace_back();
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v.emplace(v.begin());
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v.emplace(v.begin(), 1, 2, 3);
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}
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@ -49,9 +49,9 @@ int main()
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c.reserve(100);
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tracker_allocator_counter::reset();
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c.insert(c.begin(), arr10[0]);
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ok = check_construct_destroy("Insert element", 1, 0) && ok;
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ok = check_construct_destroy("Insert element", 2, 1) && ok;
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}
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ok = check_construct_destroy("Insert element", 1, 11) && ok;
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ok = check_construct_destroy("Insert element", 2, 12) && ok;
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{
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Container c(arr10, arr10 + 10);
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@ -223,7 +223,8 @@ test03()
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void
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test04()
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{
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const X::special expected{ 0, 3, 1, 0, 3, 0 };
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const X::special expected_ins{ 0, 3, 1, 0, 3, 0 };
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const X::special expected_emp{ 0, 4, 1, 0, 4, 0 };
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X::special ins, emp;
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{
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std::vector<X> v;
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@ -253,8 +254,8 @@ test04()
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// std::cout << "----\n";
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emp = X::sp;
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}
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VERIFY( ins == emp );
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VERIFY( ins == expected );
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VERIFY( ins == expected_ins );
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VERIFY( emp == expected_emp );
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}
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// insert vs emplace xvalue reallocation
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@ -39,45 +39,48 @@ int main()
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int buckets;
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// Add 1 to all counts, because the std::vector used internally by the
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// hashtable creates and destroys a temporary object using the allocator.
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tracker_allocator_counter::reset();
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{
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Container c;
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buckets = c.bucket_count();
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ok = check_construct_destroy("empty container", buckets, 0) && ok;
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ok = check_construct_destroy("empty container", buckets+1, 1) && ok;
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}
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ok = check_construct_destroy("empty container", buckets, buckets) && ok;
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ok = check_construct_destroy("empty container", buckets+1, buckets+1) && ok;
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tracker_allocator_counter::reset();
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{
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Container c(arr10, arr10 + 10);
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ok = check_construct_destroy("Construct from range", buckets+10, 0) && ok;
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ok = check_construct_destroy("Construct from range", buckets+10+1, 1) && ok;
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}
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ok = check_construct_destroy("Construct from range", buckets+10, buckets+10) && ok;
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ok = check_construct_destroy("Construct from range", buckets+10+1, buckets+10+1) && ok;
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tracker_allocator_counter::reset();
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{
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Container c(arr10, arr10 + 10);
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c.insert(arr10a[0]);
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ok = check_construct_destroy("Insert element", buckets+11, 0) && ok;
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ok = check_construct_destroy("Insert element", buckets+11+1, 1) && ok;
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}
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ok = check_construct_destroy("Insert element", buckets+11, buckets+11) && ok;
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ok = check_construct_destroy("Insert element", buckets+11+1, buckets+11+1) && ok;
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tracker_allocator_counter::reset();
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{
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Container c(arr10, arr10 + 10);
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c.insert(arr10a, arr10a+3);
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ok = check_construct_destroy("Insert short range", buckets+13, 0) && ok;
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ok = check_construct_destroy("Insert short range", buckets+13+1, 1) && ok;
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}
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ok = check_construct_destroy("Insert short range", buckets+13, buckets+13) && ok;
|
||||
ok = check_construct_destroy("Insert short range", buckets+13+1, buckets+13+1) && ok;
|
||||
|
||||
tracker_allocator_counter::reset();
|
||||
{
|
||||
Container c(arr10, arr10 + 10);
|
||||
c.insert(arr10a, arr10a+10);
|
||||
ok = check_construct_destroy("Insert long range", buckets+20, 0) && ok;
|
||||
ok = check_construct_destroy("Insert long range", buckets+20+1, 1) && ok;
|
||||
}
|
||||
ok = check_construct_destroy("Insert long range", buckets+20, buckets+20) && ok;
|
||||
ok = check_construct_destroy("Insert long range", buckets+20+1, buckets+20+1) && ok;
|
||||
|
||||
return ok ? 0 : 1;
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue