On 30/10/18 07:28 +0100, François Dumont wrote:
Following Marc Glisse change to ignore _M_start offset I wanted to go
a little step further and just remove it in _GLIBCXX_INLINE_VERSION
mode.
I also fix a regression we already fixed on mainstream std::vector
regarding noexcept qualification of move constructor with allocator.
And I implemented the same optimizations than in std::vector for
allocators always comparing equals and for the std::swap operation.
I also avoid re-implementing in vector::operator[] the same code
already implemented in iterator::operator[] but this one should
perhaps go in a different commit.
* include/bits/stl_bvector.h
[_GLIBCXX_INLINE_VERSION](_Bvector_impl_data::_M_start): Define as
_Bit_type*.
(_Bvector_impl_data(const _Bvector_impl_data&)): New.
(_Bvector_impl_data(_Bvector_impl_data&&)): Delegate to latter.
(_Bvector_impl_data::operator=(const _Bvector_impl_data&)): New.
(_Bvector_impl_data::_M_move_data(_Bvector_impl_data&&)): Use latter.
(_Bvector_impl_data::_M_reset()): Likewise.
(_Bvector_impl_data::_M_begin()): New.
(_Bvector_impl_data::_M_cbegin()): New.
(_Bvector_impl_data::_M_start_p()): New.
(_Bvector_impl_data::_M_set_start(_Bit_type*)): New.
(_Bvector_impl_data::_M_swap_data): New.
(_Bvector_impl::_Bvector_impl(_Bvector_impl&&)): Implement explicitely.
(_Bvector_impl::_Bvector_impl(_Bit_alloc_type&&,
_Bvector_impl&&)): New.
(_Bvector_base::_Bvector_base(_Bvector_base&&, const allocator_type&)):
New.
(_Bvector_base::_M_deallocate()): Adapt.
(vector::vector(const vector&, const allocator_type&)): Adapt.
(vector::vector(vector&&, const allocator_type&, true_type)): New.
(vector::vector(vector&&, const allocator_type&, false_type)): New.
(vector::vector(vector&&, const allocator_type&)): Use latters.
(vector::vector(const vector&, const allocator_type&)): Adapt.
(vector::begin()): Adapt.
(vector::cbegin()): Adapt.
(vector::operator[](size_type)): Use iterator operator[].
(vector::swap(vector&)): Adapt.
(vector::flip()): Adapt.
(vector::_M_initialize(size_type)): Adapt.
(vector::_M_initialize_value(bool)): Adapt.
* include/bits/vector.tcc:
(vector<bool>::_M_reallocate(size_type)): Adapt.
(vector<bool>::_M_fill_insert(iterator, size_type, bool)): Adapt.
(vector<bool>::_M_insert_range<_FwdIter>(iterator, _FwdIter, _FwdIter
std::forward_iterator_tag)): Adapt.
(vector<bool>::_M_insert_aux(iterator, bool)): Adapt.
(std::hash<std::vector<bool>>::operator()): Adapt.
* testsuite/23_containers/vector/bool/cons/noexcept_move_construct.cc:
Add check.
Tested under Linux x86_64.
Ok to commit ?
François
diff --git a/libstdc++-v3/include/bits/stl_bvector.h
b/libstdc++-v3/include/bits/stl_bvector.h
index 8fbef7a1a3a..81b4a75236d 100644
--- a/libstdc++-v3/include/bits/stl_bvector.h
+++ b/libstdc++-v3/include/bits/stl_bvector.h
@@ -437,7 +437,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
struct _Bvector_impl_data
{
+#if !_GLIBCXX_INLINE_VERSION
_Bit_iterator _M_start;
+#else
+ _Bit_type* _M_start;
+#endif
An alternative that would require fewer changes elsewhere in the file
would be:
#if !_GLIBCXX_INLINE_VERSION
_Bit_iterator _M_start;
#else
// We don't need the offset field for the start pointer,
// it's always zero.
struct {
_Bit_type* _M_p;
// Allow assignment from iterators (assume offset is zero):
void operator=(_Bit_iterator __it) { _M_p = __it._M_p; }
} _M_start;
#endif
Now the rest of the file doesn't need any checks for
_GLIBCXX_INLINE_VERSION (which I'd prefer to avoid, because it
clutters the code up with extra conditionals for a mode that
**nobody** uses in practice).
_Bit_iterator _M_finish;
_Bit_pointer _M_end_of_storage;
@@ -447,32 +451,74 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
#if __cplusplus >= 201103L
_Bvector_impl_data(_Bvector_impl_data&& __x) noexcept
- : _M_start(__x._M_start), _M_finish(__x._M_finish)
- , _M_end_of_storage(__x._M_end_of_storage)
+ : _Bvector_impl_data(__x)
{ __x._M_reset(); }
+ _Bvector_impl_data(const _Bvector_impl_data&) = default;
+ _Bvector_impl_data&
+ operator=(const _Bvector_impl_data&) = default;
void
_M_move_data(_Bvector_impl_data&& __x) noexcept
{
- this->_M_start = __x._M_start;
- this->_M_finish = __x._M_finish;
- this->_M_end_of_storage = __x._M_end_of_storage;
+ *this = __x;
__x._M_reset();
}
+#else
+ _Bvector_impl_data(const _Bvector_impl_data& __x)
+ : _M_start(__x._M_start), _M_finish(__x._M_finish)
+ , _M_end_of_storage(__x._M_end_of_storage)
+ { }
Do we need this definition? Won't the compiler generate the same thing
for us anyway?
+ _Bvector_impl_data&
+ operator=(const _Bvector_impl_data& __x)
+ {
+ _M_start = __x._M_start;
+ _M_finish = __x._M_finish;
+ _M_end_of_storage = __x._M_end_of_storage;
+ }
Same here.
+#endif
+
+ _Bit_iterator
+ _M_begin() const _GLIBCXX_NOEXCEPT
+ { return _Bit_iterator(_M_start_p(), 0); }
+
+ _Bit_const_iterator
+ _M_cbegin() const _GLIBCXX_NOEXCEPT
+ { return _Bit_const_iterator(_M_start_p(), 0); }
+
+ _Bit_type*
+ _M_start_p() const _GLIBCXX_NOEXCEPT
We already have _M_end_addr() so would _M_begin_addr be a better name
for this new function?
+#if !_GLIBCXX_INLINE_VERSION
+ { return _M_start._M_p; }
+#else
+ { return _M_start; }
+#endif
Using the suggestion above you wouldn't need #if because return
_M_start._M_p would always be right. But you wouldn't even need this
function at all, the code that uses _M_start._M_p would Just Work™.
+ void
+ _M_set_start(_Bit_type* __p) _GLIBCXX_NOEXCEPT
+#if !_GLIBCXX_INLINE_VERSION
+ { _M_start._M_p = __p; }
+#else
+ { _M_start = __p; }
#endif
You wouldn't need this function.
etc. etc.
void
_M_reset() _GLIBCXX_NOEXCEPT
+ { *this = _Bvector_impl_data(); }
+
+ void
+ _M_swap_data(_Bvector_impl_data& __x) _GLIBCXX_NOEXCEPT
{
- _M_start = _M_finish = _Bit_iterator();
- _M_end_of_storage = _Bit_pointer();
+ // Do not use std::swap(_M_start, __x._M_start), etc as it loses
+ // information used by TBAA.
+ std::swap(*this, __x);
}
};
struct _Bvector_impl
: public _Bit_alloc_type, public _Bvector_impl_data
{
- public:
_Bvector_impl()
_GLIBCXX_NOEXCEPT_IF( noexcept(_Bit_alloc_type()) )
You'll need to rebase the patch, because I just fixed a bug in this
exception specification (r265626).
: _Bit_alloc_type()
