[PATCH][_Hashtable] Fix some implementation inconsistencies
François Dumont
frs.dumont@gmail.com
Mon Jun 24 04:53:44 GMT 2024
Hi
Still no time ?
Thanks
On 06/06/2024 19:02, François Dumont wrote:
> No chance ?
>
> On 22/05/2024 06:50, François Dumont wrote:
>> Ping ?
>>
>> On 13/05/2024 06:33, François Dumont wrote:
>>> libstdc++: [_Hashtable] Fix some implementation inconsistencies
>>>
>>> Get rid of the different usages of the mutable keyword except in
>>> _Prime_rehash_policy where it is preserved for abi compatibility
>>> reason.
>>>
>>> Fix comment to explain that we need the computation of bucket
>>> index noexcept
>>> to be able to rehash the container when needed.
>>>
>>> For Standard instantiations through std::unordered_xxx
>>> containers we already
>>> force caching of hash code when hash functor is not noexcep so
>>> it is guarantied.
>>>
>>> The static_assert purpose in _Hashtable on _M_bucket_index is
>>> thus limited
>>> to usages of _Hashtable with exotic _Hashtable_traits.
>>>
>>> libstdc++-v3/ChangeLog:
>>>
>>> * include/bits/hashtable_policy.h
>>> (_NodeBuilder<>::_S_build): Remove
>>> const qualification on _NodeGenerator instance.
>>> (_ReuseOrAllocNode<>::operator()(_Args&&...)): Remove const
>>> qualification.
>>> (_ReuseOrAllocNode<>::_M_nodes): Remove mutable.
>>> (_Insert_base<>::_M_insert_range): Remove _NodeGetter
>>> const qualification.
>>> (_Hash_code_base<>::_M_bucket_index(const
>>> _Hash_node_value<>&, size_t)):
>>> Simplify noexcept declaration, we already static_assert
>>> that _RangeHash functor
>>> is noexcept.
>>> * include/bits/hashtable.h: Rework comments. Remove
>>> const qualifier on
>>> _NodeGenerator& arguments.
>>>
>>> Tested under Linux x64, ok to commit ?
>>>
>>> François
>>>
-------------- next part --------------
diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 361da2b3b4d..7ed68bb6c3c 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -49,7 +49,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using __cache_default
= __not_<__and_<// Do not cache for fast hasher.
__is_fast_hash<_Hash>,
- // Mandatory to have erase not throwing.
+ // Mandatory for the rehash process.
__is_nothrow_invocable<const _Hash&, const _Tp&>>>;
// Helper to conditionally delete the default constructor.
@@ -484,7 +484,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Ht, typename _NodeGenerator>
void
- _M_assign(_Ht&&, const _NodeGenerator&);
+ _M_assign(_Ht&&, _NodeGenerator&);
void
_M_move_assign(_Hashtable&&, true_type);
@@ -922,7 +922,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Kt, typename _Arg, typename _NodeGenerator>
std::pair<iterator, bool>
- _M_insert_unique(_Kt&&, _Arg&&, const _NodeGenerator&);
+ _M_insert_unique(_Kt&&, _Arg&&, _NodeGenerator&);
template<typename _Kt>
static __conditional_t<
@@ -942,7 +942,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Arg, typename _NodeGenerator>
std::pair<iterator, bool>
- _M_insert_unique_aux(_Arg&& __arg, const _NodeGenerator& __node_gen)
+ _M_insert_unique_aux(_Arg&& __arg, _NodeGenerator& __node_gen)
{
return _M_insert_unique(
_S_forward_key(_ExtractKey{}(std::forward<_Arg>(__arg))),
@@ -951,7 +951,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Arg, typename _NodeGenerator>
std::pair<iterator, bool>
- _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
+ _M_insert(_Arg&& __arg, _NodeGenerator& __node_gen,
true_type /* __uks */)
{
using __to_value
@@ -962,7 +962,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Arg, typename _NodeGenerator>
iterator
- _M_insert(_Arg&& __arg, const _NodeGenerator& __node_gen,
+ _M_insert(_Arg&& __arg, _NodeGenerator& __node_gen,
false_type __uks)
{
using __to_value
@@ -975,7 +975,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Arg, typename _NodeGenerator>
iterator
_M_insert(const_iterator, _Arg&& __arg,
- const _NodeGenerator& __node_gen, true_type __uks)
+ _NodeGenerator& __node_gen, true_type __uks)
{
return
_M_insert(std::forward<_Arg>(__arg), __node_gen, __uks).first;
@@ -985,7 +985,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Arg, typename _NodeGenerator>
iterator
_M_insert(const_iterator, _Arg&&,
- const _NodeGenerator&, false_type __uks);
+ _NodeGenerator&, false_type __uks);
size_type
_M_erase(true_type __uks, const key_type&);
@@ -1415,7 +1415,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
_Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
- _M_assign(_Ht&& __ht, const _NodeGenerator& __node_gen)
+ _M_assign(_Ht&& __ht, _NodeGenerator& __node_gen)
{
__buckets_ptr __buckets = nullptr;
if (!_M_buckets)
@@ -1657,8 +1657,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
~_Hashtable() noexcept
{
// Getting a bucket index from a node shall not throw because it is used
- // in methods (erase, swap...) that shall not throw. Need a complete
- // type to check this, so do it in the destructor not at class scope.
+ // during the rehash process. This static_assert purpose is limited to usage
+ // of _Hashtable with _Hashtable_traits requesting non-cached hash code.
+ // Need a complete type to check this, so do it in the destructor not at
+ // class scope.
static_assert(noexcept(declval<const __hash_code_base_access&>()
._M_bucket_index(declval<const __node_value_type&>(),
(std::size_t)0)),
@@ -2314,7 +2316,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
_Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
_M_insert_unique(_Kt&& __k, _Arg&& __v,
- const _NodeGenerator& __node_gen)
+ _NodeGenerator& __node_gen)
-> pair<iterator, bool>
{
const size_type __size = size();
@@ -2352,7 +2354,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal,
_Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
_M_insert(const_iterator __hint, _Arg&& __v,
- const _NodeGenerator& __node_gen,
+ _NodeGenerator& __node_gen,
false_type /* __uks */)
-> iterator
{
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h
index 26def24f24e..1c121667ef0 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -155,7 +155,7 @@ namespace __detail
{
template<typename _Kt, typename _Arg, typename _NodeGenerator>
static auto
- _S_build(_Kt&& __k, _Arg&& __arg, const _NodeGenerator& __node_gen)
+ _S_build(_Kt&& __k, _Arg&& __arg, _NodeGenerator& __node_gen)
-> typename _NodeGenerator::__node_ptr
{
return __node_gen(std::forward<_Kt>(__k),
@@ -168,7 +168,7 @@ namespace __detail
{
template<typename _Kt, typename _Arg, typename _NodeGenerator>
static auto
- _S_build(_Kt&& __k, _Arg&&, const _NodeGenerator& __node_gen)
+ _S_build(_Kt&& __k, _Arg&&, _NodeGenerator& __node_gen)
-> typename _NodeGenerator::__node_ptr
{ return __node_gen(std::forward<_Kt>(__k)); }
};
@@ -212,7 +212,7 @@ namespace __detail
template<typename... _Args>
__node_ptr
- operator()(_Args&&... __args) const
+ operator()(_Args&&... __args)
{
if (!_M_nodes)
return _M_h._M_allocate_node(std::forward<_Args>(__args)...);
@@ -230,7 +230,7 @@ namespace __detail
}
private:
- mutable __node_ptr _M_nodes;
+ __node_ptr _M_nodes;
__hashtable_alloc& _M_h;
};
@@ -555,6 +555,7 @@ namespace __detail
{ return _M_max_load_factor; }
// Return a bucket size no smaller than n.
+ // TODO: 'const' qualifier is kept for abi compatibility reason.
std::size_t
_M_next_bkt(std::size_t __n) const;
@@ -567,6 +568,7 @@ namespace __detail
// and __n_ins is number of elements to be inserted. Do we need to
// increase bucket count? If so, return make_pair(true, n), where n
// is the new bucket count. If not, return make_pair(false, 0).
+ // TODO: 'const' qualifier is kept for abi compatibility reason.
std::pair<bool, std::size_t>
_M_need_rehash(std::size_t __n_bkt, std::size_t __n_elt,
std::size_t __n_ins) const;
@@ -588,6 +590,8 @@ namespace __detail
static const std::size_t _S_growth_factor = 2;
float _M_max_load_factor;
+
+ // TODO: 'mutable' kept for abi compatibility reason.
mutable std::size_t _M_next_resize;
};
@@ -931,12 +935,12 @@ namespace __detail
template<typename _InputIterator, typename _NodeGetter>
void
_M_insert_range(_InputIterator __first, _InputIterator __last,
- const _NodeGetter&, true_type __uks);
+ _NodeGetter&, true_type __uks);
template<typename _InputIterator, typename _NodeGetter>
void
_M_insert_range(_InputIterator __first, _InputIterator __last,
- const _NodeGetter&, false_type __uks);
+ _NodeGetter&, false_type __uks);
public:
using iterator = _Node_iterator<_Value, __constant_iterators::value,
@@ -1012,7 +1016,7 @@ namespace __detail
_Hash, _RangeHash, _Unused,
_RehashPolicy, _Traits>::
_M_insert_range(_InputIterator __first, _InputIterator __last,
- const _NodeGetter& __node_gen, true_type __uks)
+ _NodeGetter& __node_gen, true_type __uks)
{
__hashtable& __h = _M_conjure_hashtable();
for (; __first != __last; ++__first)
@@ -1029,7 +1033,7 @@ namespace __detail
_Hash, _RangeHash, _Unused,
_RehashPolicy, _Traits>::
_M_insert_range(_InputIterator __first, _InputIterator __last,
- const _NodeGetter& __node_gen, false_type __uks)
+ _NodeGetter& __node_gen, false_type __uks)
{
using __rehash_guard_t = typename __hashtable::__rehash_guard_t;
using __pair_type = std::pair<bool, std::size_t>;
@@ -1359,9 +1363,7 @@ namespace __detail
std::size_t
_M_bucket_index(const _Hash_node_value<_Value, false>& __n,
std::size_t __bkt_count) const
- noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>()))
- && noexcept(declval<const _RangeHash&>()((__hash_code)0,
- (std::size_t)0)) )
+ noexcept( noexcept(declval<const _Hash&>()(declval<const _Key&>())) )
{
return _RangeHash{}(_M_hash_code(_ExtractKey{}(__n._M_v())),
__bkt_count);
@@ -1369,9 +1371,7 @@ namespace __detail
std::size_t
_M_bucket_index(const _Hash_node_value<_Value, true>& __n,
- std::size_t __bkt_count) const
- noexcept( noexcept(declval<const _RangeHash&>()((__hash_code)0,
- (std::size_t)0)) )
+ std::size_t __bkt_count) const noexcept
{ return _RangeHash{}(__n._M_hash_code, __bkt_count); }
void
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