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

[Baesken, Matthias]

Hi Magnus ,  yes IBM offers now  in xlc  16.1 both  the  legacy  xlc and  additionally  the xlclang++  .

Sooner or later we have to switch to  xlclang++  , because  the legacy  xlc will most likely not be able to support everything from  “JEP 347: Adopt C++14 Language Features in HotSpot”  .


  *   It would be really nice if we could align the xlc options more closely to gcc/clang.

In the  long run  this should be possible .


Best regards, Matthias



From: Magnus Ihse Bursie <magnus.ihse.bursie at oracle.com>
Sent: Donnerstag, 31. Januar 2019 21:19
To: Baesken, Matthias <matthias.baesken at sap.com>
Cc: build-dev at openjdk.java.net
Subject: Re: RFR : 8218136: minor hotspot adjustments for xlclang++ from xlc16 on AIX

Ah, IBM is starting to use clang? That's nice! From what I understand after a quick search, this also means that gcc/clang options are available, and recommended [1] to use. It would be really nice if we could align the xlc options more closely to gcc/clang.
/Magnus

[1] https://www.ibm.com/support/knowledgecenter/SSGH3R_16.1.0/com.ibm.xlcpp161.aix.doc/migrate/xlC_vs_xlclangpp.html


31 jan. 2019 kl. 15:50 skrev Baesken, Matthias <matthias.baesken at sap.com<mailto:matthias.baesken at sap.com>>:
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++)

- arguments.cpp/hpp  :  the UNSUPPORTED_OPTON macro lead  to assigning false to  AllocateHeapAt which is a bad idea (and does not work with xlclang++)

-   globalDefinitions_xlc.hpp   : xlclang++ sets   __GNUC__ so we must not  have #error ... in this case




Bug/webrev :

https://bugs.openjdk.java.net/browse/JDK-8218136

http://cr.openjdk.java.net/~mbaesken/webrevs/8218136.0/


Thanks, Matthias