RFR : 8218136: minor hotspot adjustments for xlclang++ from xlc16 on AIX

[Magnus Ihse Bursie]

On 2019-02-01 05:23, David Holmes wrote:
> Hi Matthias,
>
> On 1/02/2019 12:50 am, Baesken, Matthias wrote:
>> Please review  this small webrev  . It contains a few changes  for  
>> building hotspot   on AIX with xlclang++  / xlc16  .
>> ( most likely switching to   xlclang++  / xlc16    will be a must 
>> once  we introduce C++11/14 features )
>>
>> Some comments on the changes :
>>
>>
>> - porting_aix.cpp  :  workaround for demangle.h (does not work with 
>> xlclang++)
>
> Can't comment as I know nothing about it.
>
>> - arguments.cpp/hpp  :  the UNSUPPORTED_OPTON macro lead  to 
>> assigning false to AllocateHeapAt which is a bad idea (and does not 
>> work with xlclang++)
>
> Good catch!
>
>> -   globalDefinitions_xlc.hpp   : xlclang++ sets   __GNUC__ so we 
>> must not  have #error ... in this case
>
> Confused. Which other xlc compilers set __GNUC_ as you are changing 
> this for all of them? 

Unfortunately, I think __GNUC__ is set by many compilers who wish to 
express that (they believe) they are compatible with gcc (in one way or 
another). I'm pretty sure it's set by solstudio, for instance. And 
clang. But I might be wrong, and I might be thinking about some other 
gcc feature macro.

/Magnus
> Though to be honest I don't understand this whole section anyway - we 
> have a lengthy comment saying why you can't necessarily assign NULL to 
> an integer type and to use NULL_WORD instead but then it's defined as 
> NULL anyway! I wonder if we used to have some other conditions there 
> where it was something different? In any case having an if and else 
> that do exactly the same thing seems rather pointless to me.
>
> Thanks,
> David
>>
>>
>>
>> Bug/webrev :
>>
>> https://bugs.openjdk.java.net/browse/JDK-8218136
>>
>> http://cr.openjdk.java.net/~mbaesken/webrevs/8218136.0/
>>
>>
>> Thanks, Matthias
>>