(XS) RFR: 8077674: BSD build failures due to undefined macros

[Dmitry Samersoff]

David,

> True but "normal" programming style for mutually exclusive
> conditions is to use if/else style logic.

Agree in general, but I vote for better readability/error resistance here.

Also, you may consider to add "sanity" block to the top of file to
defend to incorrect defines (multiple variants, VAR = 0 etc)

-Dmitry


On 2015-04-16 09:47, David Holmes wrote:
> On 16/04/2015 4:43 PM, Dmitry Samersoff wrote:
>> David,
>>
>> As __FreeBSD__ and __OpenBSD__ etc is unlikely defined together
>> you don't need #else here.
> 
> True but "normal" programming style for mutually exclusive conditions is
> to use if/else style logic.
> 
> It's a third option I suppose, but I find it less appealing.
> 
> Thanks,
> David
> 
>> i.e.
>>
>> #ifdef __FreeBSD__
>> ...
>> #endif
>>
>> #ifdef __OpenBSD__
>> ...
>> #endif
>>
>> etc.
>>
>> -Dmitry
>>
>> On 2015-04-16 08:25, David Holmes wrote:
>>> Here's an alternate webrev based on Kim's findings in the other thread.
>>>
>>> http://cr.openjdk.java.net/~dholmes/8077674/webrev.v2/
>>>
>>> Basically #elif XXX is replaced with #else #ifdef XXX #endif". With lots
>>> of new lines of course.
>>>
>>> I don't know what the normal style rules are for nesting preprocessing
>>> conditionals. I prefer to see the # lines indented, but I know people
>>> like to see the real code at the indent it would be if there were no
>>> conditional.
>>>
>>> As I wrote here:
>>>
>>> http://mail.openjdk.java.net/pipermail/build-dev/2015-April/014801.html
>>>
>>> It seems to me there are two choices here:
>>>
>>> a) Use the [original] change proposed but verify that the variables
>>> concerned are ones that if defined will never be defined to be zero
>>> (which I believe to be the case but may have trouble proving :( )
>>>
>>> b) Replace the 'elif XXX' with 'else ifdef XXX' [v2]
>>>
>>> For the few cases involved here (b) seems the easier path.
>>>
>>> Comments/suggestions welcomed.
>>>
>>> Thanks,
>>> David
>>>
>>>
>>>
>>> On 16/04/2015 11:50 AM, David Holmes wrote:
>>>> Still need Review for this please (with plans to backport to 8u).
>>>>
>>>> Thanks,
>>>> David
>>>>
>>>> On 15/04/2015 6:25 AM, David Holmes wrote:
>>>>> Hi Dmitry,
>>>>>
>>>>> On 14/04/2015 9:25 PM, Dmitry Samersoff wrote:
>>>>>> David,
>>>>>>
>>>>>> It's better to change
>>>>>>
>>>>>> #ifdef __APPLE__
>>>>>>
>>>>>> to
>>>>>>
>>>>>> #if defined(__APPLE__)
>>>>>
>>>>> Why? They seem 100% equivalent. Plus that would mean a lot of changes.
>>>>> Plus we use that pattern in many, many, many places.
>>>>>
>>>>> Thanks,
>>>>> David
>>>>>
>>>>>> -Dmitry
>>>>>>
>>>>>>
>>>>>> On 2015-04-14 13:20, David Holmes wrote:
>>>>>>> webrev:
>>>>>>>
>>>>>>> http://cr.openjdk.java.net/~dholmes/8077674/webrev/
>>>>>>>
>>>>>>>   From the original error report:
>>>>>>>> "-Wundef option causes GCC to warn whenever it encounters an
>>>>>>>> identifier
>>>>>>>> which is not a macro in an ‘#if’. "
>>>>>>>>
>>>>>>>> Hence we should be using
>>>>>>>>
>>>>>>>> #elif defined(__FreeBSD__)
>>>>>>>>
>>>>>>>> etc in this context.
>>>>>>>
>>>>>>> I also founds similar suspect usages in os_linux.cpp and
>>>>>>> os_windows.cpp.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> David
>>>>>>
>>>>>>
>>
>>


-- 
Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the source code.