Re: [PATCH] pedantic warning behavior when casting void* to ptr-to-func, 4.8 and 4.9

[Daniel Gutson <daniel dot gutson at tallertechnologies dot com>]

Ping for maintainer please.

Thanks,

   Daniel.

On Tue, Apr 15, 2014 at 7:05 PM, Daniel Gutson
<daniel.gutson@tallertechnologies.com> wrote:
> On Tue, Apr 15, 2014 at 6:12 PM, Richard Sandiford
> <rdsandiford@googlemail.com> wrote:
>> cc:ing Jason, who's the C++ maintainer.
>
>
> FWIW: I created http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60850
>
>>
>> Daniel Gutson <daniel.gutson@tallertechnologies.com> writes:
>>> ping for maintainer.
>>>
>>> Could this be considered for 4.8.3 please?
>>>
>>> Thanks,
>>>
>>>    Daniel.
>>>
>>>
>>> On Tue, Apr 1, 2014 at 2:46 PM, Daniel Gutson
>>> <daniel.gutson@tallertechnologies.com> wrote:
>>>>
>>>> I just realized I posted the patch in the wrong list.
>>>>
>>>>
>>>> ---------- Forwarded message ----------
>>>> From: Daniel Gutson <daniel.gutson@tallertechnologies.com>
>>>> Date: Tue, Apr 1, 2014 at 10:43 AM
>>>> Subject: [PATCH] pedantic warning behavior when casting void* to
>>>> ptr-to-func, 4.8 and 4.9
>>>> To: gcc Mailing List <gcc@gcc.gnu.org>
>>>>
>>>>
>>>> Hi,
>>>>
>>>>    I observed two different behaviors in gcc 4.8.2 and 4.9 regarding
>>>> the same issue, IMO both erroneous.
>>>>
>>>> Regarding 4.8.2, #pragma GCC diagnostic ignored "-pedantic" doesn't
>>>> work in cases such as:
>>>>     void* p = 0;
>>>> #pragma GCC diagnostic ignored "-pedantic"
>>>>     F* f2 = reinterpret_cast<F*>(p);
>>>>
>>>> (see testcase in the patch).
>>>>
>>>> The attached patch attempts to fix this issue. Since I no longer have
>>>> write access, please
>>>> apply this for me if correct (is the 4.8 branch still alive for adding fixes?).
>>>>
>>>> Regarding 4.9, gcc fails to complain at all when -pedantic is passed,
>>>> even specifying -std=c++03.
>>>> Please let me know if this is truly a bug, in which case I could also
>>>> fix it for the latest version as well
>>>> (if so, please let me know if I should look into trunk or any other branch).
>>>>
>>>> Thanks,
>>>>
>>>>    Daniel.
>>>>
>>>> 2014-03-31  Daniel Gutson  <daniel.gutson@tallertechnologies.com>
>>>>
>>>> gcc/cp/
>>>>         * typeck.c (build_reinterpret_cast_1): Pass proper argument to
>>>> warn() in pedantic.
>>>>
>>>> gcc/testsuite/g++.dg/
>>>>         * diagnostic/pedantic.C: New test case.
>>
>> --- gcc-4.8.2-orig/gcc/cp/typeck.c      2014-03-31 22:29:42.736367936 -0300
>> +++ gcc-4.8.2/gcc/cp/typeck.c   2014-03-31 14:26:43.536747050 -0300
>> @@ -6639,7 +6639,7 @@
>>            where possible, and it is necessary in some cases.  DR 195
>>            addresses this issue, but as of 2004/10/26 is still in
>>            drafting.  */
>> -       warning (0, "ISO C++ forbids casting between pointer-to-function and pointer-to-object");
>> +       warning (OPT_Wpedantic, "ISO C++ forbids casting between pointer-to-function and pointer-to-object");
>>        return fold_if_not_in_template (build_nop (type, expr));
>>      }
>>    else if (TREE_CODE (type) == VECTOR_TYPE)
>> --- gcc-4.8.2-orig/gcc/testsuite/g++.dg/diagnostic/pedantic.C   1969-12-31 21:00:00.000000000 -0300
>> +++ gcc-4.8.2/gcc/testsuite/g++.dg/diagnostic/pedantic.C        2014-03-31 17:24:42.532607344 -0300
>> @@ -0,0 +1,12 @@
>> +// { dg-do compile }
>> +// { dg-options "-pedantic" }
>> +typedef void F(void);
>> +
>> +void foo()
>> +{
>> +    void* p = 0;
>> +    F* f1 = reinterpret_cast<F*>(p);    // { dg-warning "ISO" }
>> +#pragma GCC diagnostic ignored "-pedantic"
>> +    F* f2 = reinterpret_cast<F*>(p);
>> +}
>> +
>
>
>
> --
>
> Daniel F. Gutson
> Chief Engineering Officer, SPD
>
>
> San Lorenzo 47, 3rd Floor, Office 5
>
> CÃrdoba, Argentina
>
>
> Phone: +54 351 4217888 / +54 351 4218211
>
> Skype: dgutson



-- 

Daniel F. Gutson
Chief Engineering Officer, SPD


San Lorenzo 47, 3rd Floor, Office 5

CÃrdoba, Argentina


Phone: +54 351 4217888 / +54 351 4218211

Skype: dgutson