[PATCH] __debug::list use C++11 direct initialization

[Jonathan Wakely]

On 17/10/18 17:10 +0100, Jonathan Wakely wrote:
>On 17/10/18 17:03 +0100, Jonathan Wakely wrote:
>>On 09/10/18 07:11 +0200, François Dumont wrote:
>>>Here is the communication for my yesterday's patch which I thought 
>>>svn had failed to commit (I had to interrupt it).
>>>
>>>Similarly to what I've done for associative containers here is a 
>>>cleanup of the std::__debug::list implementation leveraging more 
>>>on C++11 direct initialization.
>>>
>>>I also made sure we use consistent comparison between 
>>>iterator/const_iterator in erase and emplace methods.
>>>
>>>2018-10-08  François Dumont <fdumont@gcc.gnu.org>
>>>
>>>Â Â Â  * include/debug/list (list<>::cbegin()): Use C++11 direct
>>>Â Â Â  initialization.
>>>Â Â Â  (list<>::cend()): Likewise.
>>>Â Â Â  (list<>::emplace<>(const_iterator, _Args&&...)): Likewise.
>>>Â Â Â  (list<>::insert(const_iterator, initializer_list<>)): Likewise.
>>>Â Â Â  (list<>::insert(const_iterator, size_type, const _Tp&)): Likewise.
>>>Â Â Â  (list<>::erase(const_iterator, const_iterator)): Ensure consistent
>>>Â Â Â  iterator comparisons.
>>>Â Â Â  (list<>::splice(const_iterator, list&&, const_iterator,
>>>Â Â Â  const_iterator)): Likewise.
>>>
>>>Tested under Linux x86_64 Debug mode and committed.
>>>
>>>François
>>>
>>
>>>diff --git a/libstdc++-v3/include/debug/list b/libstdc++-v3/include/debug/list
>>>index 8add1d596e0..879e1177497 100644
>>>--- a/libstdc++-v3/include/debug/list
>>>+++ b/libstdc++-v3/include/debug/list
>>>@@ -521,15 +521,17 @@ namespace __debug
>>>	// _GLIBCXX_RESOLVE_LIB_DEFECTS
>>>	// 151. can't currently clear() empty container
>>>	__glibcxx_check_erase_range(__first, __last);
>>>-	for (_Base_const_iterator __victim = __first.base();
>>>+	for (__decltype(__first.base()) __victim = __first.base();
>>
>>This change causes the regression.
>>
>>I think the problem is that the decltype is a reference, so every time
>>the loop does ++__victim it changes the iterator stored in __first.
>
>
>This would work:
>
>       typedef typename __decltype(__first)::iterator_type _Base_iter;
>	for (_Base_iter __victim = __first.base();
>	     __victim != __last.base(); ++__victim)
>
>
>Or simply:
>
>#if __cplusplus >= 201103L
>       typedef _Base_const_iterator _Base_iter;
>#else
>       typedef _Base_iterator _Base_iter;
>#endif
>	for (_Base_iter __victim = __first.base();
>	     __victim != __last.base(); ++__victim)
>
>
>Or just restore the original code which worked fine!


Unrelated to this change, I'm also seeing some test failures when run
with -O0 -D_GLIBCXX_DEBUG e.g.

make check RUNTESTFLAGS="conformance.exp=23_containers/unordered_*/cliterators.cc --target_board=unix/-O0/-D_GLIBCXX_DEBUG"

There are linker errors:

FAIL: 23_containers/unordered_map/requirements/cliterators.cc (test for excess errors)
Excess errors:
/home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/safe_local_iterator.h:332: undefined reference to `__gnu_debug::_Safe_local_iterator_base::_M_attach_single(__gnu_debug::_Safe_sequence_base*, bool)'
/home/jwakely/src/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/debug/safe_local_iterator.h:332: undefined reference to `__gnu_debug::_Safe_local_iterator_base::_M_attach_single(__gnu_debug::_Safe_sequence_base*, bool)'
collect2: error: ld returned 1 exit status
UNRESOLVED: 23_containers/unordered_map/requirements/cliterators.cc compilation failed to produce executable