Fix hashtable node deallocation

François Dumont frs.dumont@gmail.com
Fri Dec 21 17:54:00 GMT 2018


Still waiting for this (I hope) last fix before gcc 9 release...

We could perhaps make:
       _Pointer_adapter(element_type* __arg = 0)

explicit to find out if there are other places where we miss to properly 
call pointer_traits<>::pointer_to. But I aren't sure we can do it in 
this extension and I haven't tried yet.

François

On 12/16/18 2:16 PM, François Dumont wrote:
> Gentle reminder, we still have this issue pending.
>
>     * include/bits/hashtable_policy.h
> (_Hashtable_alloc<>::_M_deallocate_node_ptr(__node_type*)): New.
>     (_Hashtable_alloc<>::_M_deallocate_node(__node_type*)): Use latter.
> (_ReuseOrAllocNode<>::operator<_Arg>()(_Arg&&)): Likewise.
>     * libstdc++-v3/testsuite/util/testsuite_allocator.h
>     (CustomPointerAlloc<>::allocate(size_t, pointer)): Replace by...
>     (CustomPointerAlloc<>::allocate(size_t, const_void_pointer)): 
> ...this.
>
> François
>
> On 11/29/18 7:08 AM, François Dumont wrote:
>> I am unclear about this patch, is it accepted ?
>>
>>
>> On 11/19/18 10:19 PM, François Dumont wrote:
>>> On 11/19/18 1:34 PM, Jonathan Wakely wrote:
>>>> On 10/11/18 22:40 +0100, François Dumont wrote:
>>>>> While working on a hashtable enhancement I noticed that we are not 
>>>>> using the correct method to deallocate node if the constructor 
>>>>> throws in _ReuseOrAllocNode operator(). I had to introduce a new 
>>>>> _M_deallocate_node_ptr for that as node value shall not be destroy 
>>>>> again.
>>>>>
>>>>> I also check other places and noticed that a __node_type 
>>>>> destructor call was missing.
>>>>
>>>> That's intentional. The type has a trivial destructor, so its storage
>>>> can just be reused, we don't need to destroy it.
>>>>
>>>>
>>> Ok, do you want to also remove the other call to ~__node_type() then ?
>>>
>>> Here is the updated patch and the right ChangeLog entry:
>>>
>>>     * include/bits/hashtable_policy.h
>>> (_Hashtable_alloc<>::_M_deallocate_node_ptr(__node_type*)): New.
>>> (_Hashtable_alloc<>::_M_deallocate_node(__node_type*)): Use latter.
>>> (_ReuseOrAllocNode<>::operator<_Arg>()(_Arg&&)): Likewise.
>>>     (_Hashtable_alloc<>::_M_allocate_node): Add ~__node_type call.
>>>     * libstdc++-v3/testsuite/util/testsuite_allocator.h
>>>     (CustomPointerAlloc<>::allocate(size_t, pointer)): Replace by...
>>>     (CustomPointerAlloc<>::allocate(size_t, const_void_pointer)): 
>>> ...this.
>>>     * testsuite/23_containers/unordered_set/allocator/ext_ptr.cc: Add
>>>     check.
>>>
>>> Ok to commit ?
>>>
>>> François
>>>
>>
>



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