Re: Fix some _GLIBCXX_DEBUG pretty printer errors

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

On 5 February 2018 at 06:49, François Dumont wrote:
> Hi
>
>     Here is a patch to fix some pretty printer check errors when running
> those tests with _GLIBCXX_DEBUG.
>
>     I introduced a special rendered for the std::forward_list iterator which
> is similar to the one used for the std::list and so used inheritance, I hope
> it is not a problem for Python 2/3 compatibility.
>
>     I prefer to just rely on normal iterator rendered when we detect that
> iterator hasn't been initialized so that normal or debug modes give the same
> result.
>
>     Ok to commit ?
>
> François
>
>

>@@ -575,10 +586,12 @@ class StdDebugIteratorPrinter:
>     # and return the wrapped iterator value.
>     def to_string (self):
>         base_type = gdb.lookup_type('__gnu_debug::_Safe_iterator_base')
>+        itype = self.val.type.template_argument(0)
>         safe_seq = self.val.cast(base_type)['_M_sequence']
>-        if not safe_seq or self.val['_M_version'] != safe_seq['_M_version']:
>+        if not safe_seq:
>+            return str(self.val.cast(itype))

So what's the effect of this change when we get a value-initialized
debug iterator? It prints the wrapped (value-initialized) non-debug
iterator instead?