diff mbox series

[05/12] libstdc++: Add _Hashtable::_M_assign for the common case

Message ID 20241108154548.813315-6-jwakely@redhat.com
State New
Headers show
Series libstdc++: Refactor _Hashtable class | expand

Commit Message

Jonathan Wakely Nov. 8, 2024, 3:30 p.m. UTC 
This adds a convenient _M_assign overload for the common case where the
node generator is the _AllocNode type. Only two places need to call
_M_assign with a _ReuseOrAllocNode node generator, so all the other
calls to _M_assign can use the new overload instead of manually
constructing a node generator.

The _AllocNode::operator(Args&&...) function doesn't need to be a
variadic template. It is only ever called with a single argument of type
const value_type& or value_type&&, so could be simplified. That isn't
done in this commit.

libstdc++-v3/ChangeLog:

	* include/bits/hashtable.h (_Hashtable): Remove typedefs for
	node generators.
	(_Hashtable::_M_assign(_Ht&&)): Add new overload.
	(_Hashtable::operator=(initializer_list<value_type>)): Add local
	typedef for node generator.
	(_Hashtable::_M_assign_elements): Likewise.
	(_Hashtable::operator=(const _Hashtable&)): Use new _M_assign
	overload.
	(_Hashtable(const _Hashtable&)): Likewise.
	(_Hashtable(const _Hashtable&, const allocator_type&)):
	Likewise.
	(_Hashtable(_Hashtable&&, __node_alloc_type&&, false_type)):
	Likewise.
	* include/bits/hashtable_policy.h (_Insert): Remove typedef for
	node generator.

Reviewed-by: François Dumont <fdumont@gcc.gnu.org>
---

Most of this patch series *removes* overloaded names, making overload
resolution simpler. This one adds an overload of _M_assign where there
was previously only one function template with that name. I think the
increased usability for the common case is worth it.

 libstdc++-v3/include/bits/hashtable.h        | 34 +++++++++++---------
 libstdc++-v3/include/bits/hashtable_policy.h |  1 -
 2 files changed, 19 insertions(+), 16 deletions(-)
diff mbox series

Patch

diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 23484f711cc..bf6eed7c1c6 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -299,12 +299,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 					    _Equal, _Hash, _RangeHash, _Unused,
 					    _RehashPolicy, _Traits>;
 
-      using __reuse_or_alloc_node_gen_t =
-	__detail::_ReuseOrAllocNode<__node_alloc_type>;
-      using __alloc_node_gen_t =
-	__detail::_AllocNode<__node_alloc_type>;
-      using __node_builder_t =
-	__detail::_NodeBuilder<_ExtractKey>;
+      using __node_builder_t = __detail::_NodeBuilder<_ExtractKey>;
 
       // Simple RAII type for managing a node containing an element
       struct _Scoped_node
@@ -480,6 +475,14 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	void
 	_M_assign_elements(_Ht&&);
 
+      template<typename _Ht>
+	void
+	_M_assign(_Ht&& __ht)
+	{
+	  __detail::_AllocNode<__node_alloc_type> __alloc_node_gen(*this);
+	  _M_assign(std::forward<_Ht>(__ht), __alloc_node_gen);
+	}
+
       template<typename _Ht, typename _NodeGenerator>
 	void
 	_M_assign(_Ht&&, _NodeGenerator&);
@@ -608,6 +611,9 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _Hashtable&
       operator=(initializer_list<value_type> __l)
       {
+	using __reuse_or_alloc_node_gen_t =
+	  __detail::_ReuseOrAllocNode<__node_alloc_type>;
+
 	__reuse_or_alloc_node_gen_t __roan(_M_begin(), *this);
 	_M_before_begin._M_nxt = nullptr;
 	clear();
@@ -1308,10 +1314,9 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	      _M_bucket_count = __ht._M_bucket_count;
 	      _M_element_count = __ht._M_element_count;
 	      _M_rehash_policy = __ht._M_rehash_policy;
-	      __alloc_node_gen_t __alloc_node_gen(*this);
 	      __try
 		{
-		  _M_assign(__ht, __alloc_node_gen);
+		  _M_assign(__ht);
 		}
 	      __catch(...)
 		{
@@ -1340,6 +1345,9 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		 _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::
       _M_assign_elements(_Ht&& __ht)
       {
+	using __reuse_or_alloc_node_gen_t =
+	  __detail::_ReuseOrAllocNode<__node_alloc_type>;
+
 	__buckets_ptr __former_buckets = nullptr;
 	std::size_t __former_bucket_count = _M_bucket_count;
 	__rehash_guard_t __rehash_guard(_M_rehash_policy);
@@ -1517,8 +1525,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_element_count(__ht._M_element_count),
       _M_rehash_policy(__ht._M_rehash_policy)
     {
-      __alloc_node_gen_t __alloc_node_gen(*this);
-      _M_assign(__ht, __alloc_node_gen);
+      _M_assign(__ht);
     }
 
   template<typename _Key, typename _Value, typename _Alloc,
@@ -1572,8 +1579,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_element_count(__ht._M_element_count),
       _M_rehash_policy(__ht._M_rehash_policy)
     {
-      __alloc_node_gen_t __alloc_node_gen(*this);
-      _M_assign(__ht, __alloc_node_gen);
+      _M_assign(__ht);
     }
 
   template<typename _Key, typename _Value, typename _Alloc,
@@ -1612,12 +1618,10 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	}
       else
 	{
-	  __alloc_node_gen_t __alloc_gen(*this);
-
 	  using _Fwd_Ht = __conditional_t<
 	    __move_if_noexcept_cond<value_type>::value,
 	    const _Hashtable&, _Hashtable&&>;
-	  _M_assign(std::forward<_Fwd_Ht>(__ht), __alloc_gen);
+	  _M_assign(std::forward<_Fwd_Ht>(__ht));
 	  __ht.clear();
 	}
     }
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h b/libstdc++-v3/include/bits/hashtable_policy.h
index caedb0258ef..cf97e571c1e 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -978,7 +978,6 @@  namespace __detail
 
       using __unique_keys = typename _Traits::__unique_keys;
       using __node_alloc_type = typename __hashtable_alloc::__node_alloc_type;
-      using __node_gen_type = _AllocNode<__node_alloc_type>;
 
       [[__gnu__::__always_inline__]]
       __hashtable&