On 15/02/2024 14:17, Jonathan Wakely wrote:
On Wed, 14 Feb 2024 at 21:48, François Dumont <frs.dum...@gmail.com>
wrote:
On 14/02/2024 20:44, Jonathan Wakely wrote:
On Wed, 14 Feb 2024 at 18:39, François Dumont
<frs.dum...@gmail.com> wrote:
libstdc++: [_GLIBCXX_DEBUG] Fix std::__niter_base behavior
std::__niter_base is used in _GLIBCXX_DEBUG mode to remove
_Safe_iterator<>
wrapper on random access iterators. But doing so it should
also preserve
original
behavior to remove __normal_iterator wrapper.
libstdc++-v3/ChangeLog:
* include/bits/stl_algobase.h (std::__niter_base):
Redefine the
overload
definitions for __gnu_debug::_Safe_iterator.
* include/debug/safe_iterator.tcc (std::__niter_base):
Adapt
declarations.
Ok to commit once all tests completed (still need to check
pre-c++11) ?
The declaration in include/bits/stl_algobase.h has a
noexcept-specifier but the definition in
include/debug/safe_iterator.tcc does not have one - that seems
wrong (I'm surprised it even compiles).
It does !
The diagnostic is suppressed without -Wsystem-headers:
/home/jwakely/gcc/14/include/c++/14.0.1/debug/safe_iterator.tcc:255:5:warning:
declaration of 'template<class _Ite, class _Seq> constexpr decltype
(std::__
niter_base(declval<_Ite>())) std::__niter_base(const
__gnu_debug::_Safe_iterator<_Iterator, _Sequence,
random_access_iterator_tag>&)' has a different except
ion specifier [-Wsystem-headers]
255 | __niter_base(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq,
| ^~~~~~~~~~~~
/home/jwakely/gcc/14/include/c++/14.0.1/bits/stl_algobase.h:335:5:note:
from previous declaration 'template<class _Ite, class _Seq> constexpr
decltype (std
::__niter_base(declval<_Ite>())) std::__niter_base(const
__gnu_debug::_Safe_iterator<_Iterator, _Sequence,
random_access_iterator_tag>&) noexcept (noexcept
(is_nothrow_copy_constructible<decltype
(std::__niter_base(declval<_Ite>()))>::value))'
335 | __niter_base(const ::__gnu_debug::_Safe_iterator<_Ite, _Seq,
| ^~~~~~~~~~~~
It's a hard error with Clang though:
deb.cc:7:10: error: call to '__niter_base' is ambiguous
Yes, I eventually got the error too, I hadn't run enough tests yet.
I thought it was only necessary at declaration, and I also had
troubles doing it right at definition because of the interaction
with the auto and ->.
The trailing-return-type has to come after the noexcept-specifier.
Now simplified and consistent in this new proposal.
Just using std::is_nothrow_copy_constructible<_Ite> seems
simpler, that will be true for __normal_iterator<I, C> if
is_nothrow_copy_constructible<I> is true.
Ok
The definition in include/debug/safe_iterator.tcc should use
std::declval<_Ite>() not declval<_Ite>(). Is there any reason why
the definition uses a late-specified-return-type (i.e. auto and
->) when the declaration doesn't?
I initially plan to use '->
std::decltype(std::__niter_base(__it.base()))' but this did not
compile, ambiguity issue. So I resort to using std::declval and I
could have then done it the same way as declaration, done now.
Attached is what I'm testing, ok to commit once fully tested ?
OK, thanks.
Thanks for validation but I have a problem to test for c++98.
When I do:
make CXXFLAGS=-std=c++98 check-debug
I see in debug/libstdc++.log for example:
Executing on host: /home/fdumont/dev/gcc/build/./gcc/xg++ -shared-libgcc
... -mshstk -std=c++98 -g -O2 -DLOCALEDIR="." -nostdinc++
-I/home/fdumont/dev/gcc/...
/home/fdumont/dev/gcc/git/libstdc++-v3/testsuite/25_algorithms/copy/3.cc
-D_GLIBCXX_DEBUG -std=gnu++17 -include bits/stdc++.h ... -lm -o
./3.exe (timeout = 360)
The -std=c++98 is there but later comes the -std=gnu++17 so I think it
runs in C++17, no ?
I also tried the documented alternative:
make check
'RUNTESTFLAGS=--target_board=unix/-O3\"{-std=gnu++98,-std=gnu++11,-std=gnu++14}\"'
but same problem, -std=gnu++17 comes last.
I'll try to rebuild all from scratch but I won't commit soon then.
