Here is the updated and tested patch.

On 21/08/2023 20:07, Jonathan Wakely wrote:
> On Mon, 21 Aug 2023 at 18:05, François Dumont via Libstdc++
> <libstdc++@gcc.gnu.org> wrote:
>> Hi
>>
>> Here is a propocal to fix tests sensitive to libstdc++ internal allocations.
> Surely the enter() and exit() calls should be a constructor and destructor?
>
> The constructor could use count() to get the count, and then restore
> it in the destructor. Something like:
>
> --- a/libstdc++-v3/testsuite/util/replacement_memory_operators.h
> +++ b/libstdc++-v3/testsuite/util/replacement_memory_operators.h
> @@ -75,12 +75,30 @@ namespace __gnu_test
>        counter& cntr = get();
>        cntr._M_increments = cntr._M_decrements = 0;
>      }
> +
> +    struct scope
> +    {
> +      scope() : _M_count(counter::count()) { }
> +      ~scope() { counter::get()._M_count = _M_count; }
> +
> +    private:
> +      std::size_t _M_count;
> +
> +#if __cplusplus >= 201103L
> +      scope(const scope&) = delete;
> +      scope& operator=(const scope&) = delete;
> +#else
> +      scope(const scope&);
> +      scope& operator=(const scope&);
> +#endif
> +    };
>    };
>
>    template<typename Alloc, bool uses_global_new>
>      bool
>      check_new(Alloc a = Alloc())
>      {
> +      __gnu_test::counter::scope s;
>        __gnu_test::counter::exceptions(false);
>        __gnu_test::counter::reset();
>        (void) a.allocate(10);
>
>
>
>
>
>
>> Tested by restoring allocation in tzdb.cc.
>>
>> As announced I'm also adding a test to detect such allocations. If it is
>> ok let me know if you prefer to see it in a different place.
> The test is a good idea. I think 17_intro/no_library_allocation.cc
> would be a better place for it.
>
>>       libstdc++: Fix tests relying on operator new/delete overload
>>
>>       Fix tests that are checking for an allocation plan. They are failing if
>>       an allocation is taking place outside the test.
>>
>>       libstdc++-v3/ChangeLog
>>
>>               * testsuite/util/replacement_memory_operators.h
>>               (counter::_M_pre_enter_count): New.
>>               (counter::enter, counter::exit): New static methods to call
>> on main() enter/exit.
>>               * testsuite/23_containers/unordered_map/96088.cc (main):
>>               Call __gnu_test::counter::enter/exit.
>>               * testsuite/23_containers/unordered_multimap/96088.cc
>> (main): Likewise.
>>               * testsuite/23_containers/unordered_multiset/96088.cc
>> (main): Likewise.
>>               * testsuite/23_containers/unordered_set/96088.cc (main):
>> Likewise.
>>               * testsuite/ext/malloc_allocator/deallocate_local.cc
>> (main): Likewise.
>>               * testsuite/ext/new_allocator/deallocate_local.cc (main):
>> Likewise.
>>               * testsuite/ext/throw_allocator/deallocate_local.cc (main):
>> Likewise.
>>               * testsuite/ext/pool_allocator/allocate_chunk.cc (started):
>> New global.
>>               (operator new(size_t)): Check started.
>>               (main): Set/Unset started.
>>               * testsuite/ext/no_library_allocation.cc: New test case.
>>
>> Ok to commit ?
>>
>> François