Here is a new attempt preserving symbols.
libstdc++: Make debug iterator pointer sequence const [PR116369]
In revision a35dd276cbf6236e08bcf6e56e62c2be41cf6e3c the debug
sequence
have been made mutable to allow attach iterators to const containers.
This change completes this fix by also declaring debug unordered
container
members mutable.
Additionally the debug iterator sequence is now a
pointer-to-const and so
_Safe_sequence_base _M_attach and all other methods are const
qualified.
Not-const methods exported are preserved for abi backward
compatibility. The
new const methods are calling the latter thanks to a safe use of
const_cast.
libstdc++-v3/ChangeLog:
PR c++/116369
* include/debug/safe_base.h
(_Safe_iterator_base::_M_sequence): Declare as
pointer-to-const.
(_Safe_iterator_base::_M_attach, _M_attach_single): New,
take pointer-to-const
_Safe_sequence_base.
(_Safe_sequence_base::_M_detach_all, _M_detach_singular,
_M_revalidate_singular)
(_M_swap, _M_get_mutex): New, const qualified.
(_Safe_sequence_base::_M_attach, _M_attach_single,
_M_detach, _M_detach_single):
const qualify.
* include/debug/safe_container.h
(_Safe_container<>::_M_cont): Add const qualifier.
(_Safe_container<>::_M_swap_base): New.
(_Safe_container(_Safe_container&&, const _Alloc&,
std::false_type)):
Adapt to use latter.
(_Safe_container<>::operator=(_Safe_container&&)): Likewise.
(_Safe_container<>::_M_swap): Likewise and take parameter
as const reference.
* include/debug/safe_unordered_base.h
(_Safe_local_iterator_base::_M_safe_container): New.
(_Safe_local_iterator_base::_Safe_local_iterator_base): Take
_Safe_unordered_container_base as pointer-to-const.
(_Safe_unordered_container_base::_M_attach,
_M_attach_single): New, take
container as _Safe_unordered_container_base pointer-to-const.
(_Safe_unordered_container_base::_M_local_iterators,
_M_const_local_iterators):
Add mutable.
(_Safe_unordered_container_base::_M_detach_all, _M_swap):
New, const qualify.
(_Safe_unordered_container_base::_M_attach_local,
_M_attach_local_single)
(_M_detach_local, _M_detach_local_single): Add const
qualifier.
* include/debug/safe_iterator.h
(_Safe_iterator<>::_M_attach, _M_attach_single):
Take _Safe_sequence_base as pointer-to-const.
(_Safe_iterator<>::_M_get_sequence): Add const_cast and
comment about it.
* include/debug/safe_local_iterator.h
(_Safe_local_iterator<>): Replace usages
of _M_sequence member by _M_safe_container().
(_Safe_local_iterator<>::_M_attach, _M_attach_single): Take
_Safe_unordered_container_base as pointer-to-const.
(_Safe_local_iterator<>::_M_get_sequence): Rename into...
(_Safe_local_iterator<>::_M_get_ucontainer): ...this. Add
necessary const_cast and
comment to explain it.
(_Safe_local_iterator<>::_M_is_begin, _M_is_end): Adapt.
* include/debug/safe_local_iterator.tcc: Adapt.
* include/debug/safe_sequence.h
(_Safe_sequence<>::_M_invalidate_if,
_M_transfer_from_if): Add const qualifier.
* include/debug/safe_sequence.tcc: Adapt.
* include/debug/deque (std::__debug::deque::erase): Adapt
to use new const
qualified methods.
* include/debug/formatter.h: Adapt.
* include/debug/forward_list
(_Safe_forward_list::_M_this): Add const
qualification.
(_Safe_forward_list::_M_swap_aux): Rename into...
(_Safe_forward_list::_S_swap_aux): ...this and take
sequence as const reference.
(forward_list<>::resize): Adapt to use const methods.
* include/debug/list (list<>::resize): Likewise.
* src/c++11/debug.cc: Adapt to const qualification.
* testsuite/util/testsuite_containers.h
(forward_members_unordered::forward_members_unordered):
Add check on local_iterator
conversion to const_local_iterator.
(forward_members::forward_members): Add check on iterator
conversion to
const_iterator.
*
testsuite/23_containers/unordered_map/const_container.cc: New test case.
*
testsuite/23_containers/unordered_multimap/const_container.cc: New
test case.
*
testsuite/23_containers/unordered_multiset/const_container.cc: New
test case.
*
testsuite/23_containers/unordered_set/const_container.cc: New test case.
*
testsuite/23_containers/vector/debug/mutex_association.cc: Adapt.
Tested under Linux x86_64.
Ok to commit ?
François
On 26/05/2025 19:07, François Dumont wrote:
Ok, I'll give it another try.
Trying to use the same approach for targets using gnu.ver and others
thought, seems more reasonable to me.
François
On 22/05/2025 09:28, Jonathan Wakely wrote:
On Thu, 22 May 2025, 08:26 Jonathan Wakely, <jwakely....@gmail.com>
wrote:
On Thu, 15 May 2025, 06:26 François Dumont,
<frs.dum...@gmail.com> wrote:
Got
On 14/05/2025 18:46, Jonathan Wakely wrote:
> On Wed, 14 May 2025 at 17:31, François Dumont
<frs.dum...@gmail.com> wrote:
>> On 12/05/2025 23:03, Jonathan Wakely wrote:
>>> On 31/03/25 22:20 +0200, François Dumont wrote:
>>>> Hi
>>>>
>>>> Following this previous patch
>>>>
https://gcc.gnu.org/pipermail/libstdc++/2024-August/059418.html
I've
>>>> completed it for the _Safe_unordered_container_base
type and
>>>> implemented the rest of the change to store the safe
iterator
>>>> sequence as a pointer-to-const.
>>>>
>>>> libstdc++: Make debug iterator pointer sequence
const [PR116369]
>>>>
>>>> In revision
a35dd276cbf6236e08bcf6e56e62c2be41cf6e3c the debug
>>>> sequence
>>>> have been made mutable to allow attach iterators
to const
>>>> containers.
>>>> This change completes this fix by also declaring
debug unordered
>>>> container
>>>> members mutable.
>>>>
>>>> Additionally the debug iterator sequence is now a
>>>> pointer-to-const and so
>>>> _Safe_sequence_base _M_attach and all other
methods are const
>>>> qualified.
>>>> Symbols export are maintained thanks to __asm
directives.
>>>>
>>> I can't compile this, it seems to be missing changes to
>>> safe_local_iterator.tcc:
>>>
>>> In file included from
>>>
/home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/safe_local_iterator.h:444,
>>> from
>>>
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++11/debug.cc:33:
>>>
/home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/safe_local_iterator.tcc:
>>> In member function ‘typename
>>> __gnu_debug::_Distance_traits<_Iterator>::__type
>>> __gnu_debug::_Safe_local_iterator<_Iterator,
>>> _Sequence>::_M_get_distance_to(const
>>> __gnu_debug::_Safe_local_iterator<_Iterator,
_Sequence>&) const’:
>>>
/home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/safe_local_iterator.tcc:47:17:
>>> error: there are no arguments to ‘_M_get_sequence’ that
depend on a
>>> template parameter, so a declaration of
‘_M_get_sequence’ must be
>>> available [-Wtemplate-body]
>>> 47 | _M_get_sequence()->bucket_size(bucket()),
>>> | ^~~~~~~~~~~~~~~
>>>
/home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/safe_local_iterator.tcc:47:17:
>>> note: (if you use ‘-fpermissive’, G++ will accept your
code, but
>>> allowing the use of an undeclared name is deprecated)
>>>
/home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/safe_local_iterator.tcc:59:18:
>>> error: there are no arguments to ‘_M_get_sequence’ that
depend on a
>>> template parameter, so a declaration of
‘_M_get_sequence’ must be
>>> available [-Wtemplate-body]
>>> 59 | -_M_get_sequence()->bucket_size(bucket()),
>>> | ^~~~~~~~~~~~~~~
>>>
>> Yes, sorry, I had already spotted this problem, but only
updated the PR
>> and not re-sending patch here.
>>
>>
>>>> Also available as a PR
>>>>
>>>> https://forge.sourceware.org/gcc/gcc-TEST/pulls/47
>>>>
>>>> /** Detach all singular iterators.
>>>> * @post for all iterators i attached to this
sequence,
>>>> * i->_M_version == _M_version.
>>>> */
>>>> void
>>>> - _M_detach_singular();
>>>> + _M_detach_singular() const
>>>> +
__asm("_ZN11__gnu_debug19_Safe_sequence_base18_M_detach_singularEv");
>>> Does this work on all targets?
>> No idea ! I thought the symbol name used here just had
to match the
>> entries in config/abi/pre/gnu.ver.
> That linker script is not used for all targets.
Ok, got it, I only need to use this when symbol versioning
is activated.
I don't think that's right. For targets that don't use gnu.ver
we still want to preserve the same symbols. They just aren't
versioned on those targets.
And e.g. Solaris uses versioning, but a different format, not
gnu.ver, and I don't remember it the same macro is defined.
Isn't it possible to do this without asm somehow? At least as a
fallback for targets that don't use gnu.ver
Basically this needs more research, and then testing on other targets.
I think this new patch should do it if so.
François
