[Mesa-dev] [PATCH 1/2] util: Make unreachable at least be an assert

[Ian Romanick]

On 12/05/2014 01:54 PM, Ian Romanick wrote:
> On 12/05/2014 01:50 PM, Matt Turner wrote:
>> On Fri, Dec 5, 2014 at 1:48 PM, Ian Romanick <idr at freedesktop.org> wrote:
>>> On 12/05/2014 01:42 PM, Matt Turner wrote:
>>>> On Fri, Dec 5, 2014 at 1:25 PM, Ian Romanick <idr at freedesktop.org> wrote:
>>>>> On 12/05/2014 01:17 PM, Carl Worth wrote:
>>>>>> Previously, if __builtin_unreachable() was unavailable, the
>>>>>> unreachable macro was defined to do nothing. We do better here, by at
>>>>>> least still making it an assert.
>>>>>> ---
>>>>>>  src/util/macros.h | 2 +-
>>>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/src/util/macros.h b/src/util/macros.h
>>>>>> index 5fc6729..eec8b93 100644
>>>>>> --- a/src/util/macros.h
>>>>>> +++ b/src/util/macros.h
>>>>>> @@ -82,7 +82,7 @@ do {                        \
>>>>>>  #endif
>>>>>>
>>>>>>  #ifndef unreachable
>>>>>> -#define unreachable(str)
>>>>>> +#define unreachable(str) assert(!str)
>>>>>
>>>>> I'd make this ASSERT.  In Mesa, ASSERT only exists if DEBUG is defined.
>>>>>  It seems that many distros build without -DDEBUG and without -DNDEBUG.
>>>>>  I'd rather have no code for these cases in all release builds.
>>>>
>>>> I'm surprised by that.
>>>>
>>>> I see that we add -DDEBUG with --enable-debug, but from experience
>>>> assert() does nothing in my regular release build (without
>>>> --enable-debug). Where is NDEBUG coming from in that case? I don't see
>>>> it in the macros gcc automatically defines (gcc -g -dM -E - <
>>>> /dev/null).
>>>
>>> Right... and you need NDEBUG to no-op assert.  It has to be added by
>>> hand, and it seems that the distros don't.
>>
>> But I don't get assert()s in release builds, and I'm not adding NDEBUG anywhere.
> 
> That's weird... I just (today) had a case where an assert() was in a
> release build, but the same ASSERT() was not.  Maybe something weird is
> just happening on my end... let me double check my stuff.

Never mind.  PEBKAC.

Patch, as is, is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

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