r184005 - Suppress the c++11 -Wdeprecated warning for 'register' ifit is expanded from a

[David Blaikie]

On Sun, Jun 16, 2013 at 9:15 AM, Andy Gibbs <andyg1001 at hotmail.co.uk> wrote:
> On Friday, June 14, 2013 11:05 PM, Richard Smith wrote:
>>
>> Author: rsmith
>> Date: Fri Jun 14 16:05:24 2013
>> New Revision: 184005
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=184005&view=rev
>> Log:
>> Suppress the c++11 -Wdeprecated warning for 'register' if it is expanded
>> from a
>> macro defined in a system header. glibc uses it in macros, apparently.
>
>
> Not just glibc, I'm afraid.  Here's the output from using python headers:
>
> In file included from /usr/include/python2.7/Python.h:94:
> /usr/include/python2.7/stringobject.h:173:5: warning: 'register' storage
> class specifier is deprecated [-Wdeprecated]
>    register PyObject *obj,     /* string or Unicode object */
>    ^~~~~~~~~
> /usr/include/python2.7/stringobject.h:174:5: warning: 'register' storage
> class specifier is deprecated [-Wdeprecated]
>    register char **s,          /* pointer to buffer variable */
>    ^~~~~~~~~
> /usr/include/python2.7/stringobject.h:175:5: warning: 'register' storage
> class specifier is deprecated [-Wdeprecated]
>    register Py_ssize_t *len    /* pointer to length variable or NULL
>    ^~~~~~~~~
>
> I expect it is unreasonable to ask for all "system" headers to be exempt
> (which would be nice!), so as an alternative suggestion, can the warning
> group be changed to something more specific, e.g. -Wdeprecated-register, so
> that it can be disabled without having to disable the whole -Wdeprecated
> warning?  Unfortunately, deprecating "register" while laudable in the
> long-term breaks things in the short term like gcc's deprecation of
> std::auto_ptr did for many people.  It would be nice to have an easier
> upgrade path for all those projects compiled -Werror.

Given that I assume we don't actually respect the 'register' keyword
at all (it's only a hint, not a guarantee, so far as I know) I assume
it would OK to provide fixit hint that just suggests removing the
'register' keyword. That would make for a fairly easy upgrade - simply
running clang in -fixit mode.

(though, yes, I think most of these deprecations probably need a
separate flag since they'll each need to be assessed & addressed
separately in a given codebase)

>
> Cheers,
>
> Andy
>
>
>
>
>
>
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