Pretty printers for versioned namespace

[François Dumont]

On 29/11/2016 21:17, Jonathan Wakely wrote:
> On 28/11/16 22:19 +0100, François Dumont wrote:
>> Hi
>>
>>    Here is a patch to fix pretty printers when versioned namespace is 
>> activated.
>>
>>    You will see that I have hesitated in making the fix independant 
>> of the version being used. In source files you will find (__7::)? 
>> patterns while in xmethods.py I chose (__\d+::)? making it ready for 
>> __8 and forward. Do you want to generalize one option ? If so which 
>> one ?
>
> I don't really mind, but I note that the point of the path
> libstdcxx/v6/printers.py was that we'd have different printers for v7,
> v8 etc. ... I think it's simpler to keep everything in one place
> though.

Ok, I think the folder v6 depends more on a potential gdb api change.

>>    At the moment version namespace is visible within gdb, it displays 
>> for instance 'std::__7::string'. I am pretty sure we could hide it, 
>> is it preferable ? I would need some time to do so as I am neither a 
>> python nor regex expert.
>
> It's fine to display it.
>
>>    I am not fully happy with the replication in printers.py of 
>> StdRbtreeIteratorPrinter and 
>> StdExpAnyPrinter(SingleObjContainerPrinter in respectively 
>> StdVersionedRbtreeIteratorPrinter and 
>> StdExpVerAnyPrinter(SingleObjContainerPrinter just to adapt 2 lines 
>> where regex is not an option. We could surely keep only one and pass 
>> it '' or '__7'. But as I said I am not a python expert so any help 
>> would be appreciated.
>
> We definitely want to avoid that duplication. For
> StdRbtreeIteratorPrinter you can just look at 'typename' and see
> whether it starts with "std::__7" or not. If it does, you need to lookup
> std::__7::_Rb_tree_node<...>, otherwise you need to lookup
> std::_Rb_tree_node<...> instead.
>
> For StdExpAnyPrinter just do two replacements: first replace
> std::string with the result of gdb.lookup_type('std::string') and then
> replace std::__7::string with the result of looking that up. Are you
> sure that's even needed though? Does std::__7::string actually appear
> in the manager function's name? I would expect it to appear as
> std::__7::basic_string<char, std::__7::char_traits<char>, 
> std::__7::allocator<char> > >
> which doesn't need to be expanded anyway. So I think you can just
> remove your StdExpVerAnyPrinter.

We needed the StdExpVerAnyPrinter just because of the loopkup for 
'std::string' which has to be 'std::__7::string'. But I used similar 
technique exposed previously to get rid of it.

So here is the simplified version I plan to test without versioned 
namespace.

François

-------------- next part --------------
A non-text attachment was scrubbed...
Name: prettyprinters.patch
Type: text/x-patch
Size: 54356 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20161201/9d0b4600/attachment.bin>