[cfe-dev] Problems in __builtin_offsetof locations

[Douglas Gregor]

On Nov 4, 2009, at 8:04 AM, Abramo Bagnara wrote:

> Douglas Gregor ha scritto:
>>
>> On Nov 4, 2009, at 1:07 AM, Abramo Bagnara wrote:
>>
>>>
>>> The attached C source show two different problems:
>>>
>>> $ llvm_new/Debug/bin/clang-cc -W -Wall bug_clang2.c
>>> bug_clang2.c:11:7: error: too many arguments to function call
>>> fun(333);
>>> ~~~ ^~~
>>> bug_clang2.c:12:7: error: too many arguments to function call
>>> fun(__builtin_offsetof(struct s, g));
>>> ~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> bug_clang2.c:13:7: error: too many arguments to function call
>>> fun(__builtin_offsetof(struct s, f));
>>> ~~~ ^
>>> 3 diagnostics generated.
>>>
>>>
>>> 1) As seen in diagnostic for line 12, the end location of
>>> __builtin_offsetof is not the right paren but the end of location of
>>> subexpression (like in all other prefix unary operators). This is  
>>> wrong
>>> for __builtin_offsetof.
>>>
>>> 2) Worse in diagnostic for line 13, the end location of
>>> __builtin_offsetof is invalid (here I don't fully understand how  
>>> this
>>> happens).
>>
>> In general, when you come across a bug like this, please file it in  
>> the
>> LLVM Bugzilla at
>>
>>    http://llvm.org/bugs/
>
> I've already done that. Are you meaning that it was better to *only*
> file it in the LLVM Bugzilla?

Yes, please.

> In general we prefer to send the info about the problem found here to
> get some feedback about and then decide whether is better to submit
> directly a patch (if we think to be able to do something that meet the
> agreement of core developers) or to submit a bug report.
>
> Is it the correct behaviour?


For something that is clearly a bug, I think it's best to just file a  
Bugzilla. If all of the bugs that got filed against Clang went to this  
mailing list, that traffic could drown out design discussions,  
questions from Clang users, etc. At some point, we'll probably have a  
dedicated "bugs" list for Clang where we could discuss specific bugs.

Of course, if the bug needs some discussion, e.g., because you're  
interested in talking over how the bug could be fixed, then by all  
means please mail the list.

   - Doug