PR35503 - warn for restrict pointer (-Wrestrict)

[Eric Gallager]

On 8/29/16, Jason Merrill <jason@redhat.com> wrote:
> On Mon, Aug 29, 2016 at 10:28 AM, Marek Polacek <polacek@redhat.com> wrote:
>> On Mon, Aug 29, 2016 at 09:20:53AM -0400, Eric Gallager wrote:
>>> I tried this patch on my fork of gdb-binutils and got a few warnings
>>> from it. Would it be possible to have the caret point to the argument
>>> mentioned, instead of the function name? And also print the option
>>> name? E.g., instead of the current:
>>>
>>> or32-opc.c: In function ‘or32_print_register’:
>>> or32-opc.c:956:3: warning: passing argument 1 to restrict qualified
>>> parameter aliases with argument 3
>>>    sprintf (disassembled, "%sr%d", disassembled, regnum);
>>>    ^~~~~~~
>>>
>>> could it look like:
>>>
>>> or32-opc.c: In function ‘or32_print_register’:
>>> or32-opc.c:956:3: warning: passing argument 1 to restrict qualified
>>> parameter aliases with argument 3 [-Wrestrict]
>>>    sprintf (disassembled, "%sr%d", disassembled, regnum);
>>>             ^~~~~~~~~~~~
>>>
>>> instead?
>>
>> I didn't try to implement it, but I think this should be fairly easy to
>> achieve in the C FE, because c_parser_postfix_expression_after_primary
>> has arg_loc, which is a vector of parameter locations.
>
> The C++ FE doesn't have this currently, but it could be added without
> too much trouble: in cp_parser_parenthesized_expression_list, extract
> the locations from the cp_expr return value of
> cp_parser_assignment_expression, and then pass the locations back up
> to cp_parser_postfix_expression.
>
> Jason
>


On the topic of how to get this warning working with various
frontends, is there any reason why the Objective C frontend doesn't
handle -Wrestrict? Currently when trying to use it, it just says:

cc1obj: warning: command line option '-Wrestrict' is valid for C/C++
but not for ObjC