AllocateHeapAt disabling on AIX

[Baesken, Matthias]

Hi David,  I would like to  print something like  "AllocateHeapAt  not supported on AIX" .
And then exit   (probably just ignoring the flag and printing the message might be bad ).

The constraint functions were suggested to me as an option but  it looks to me they are 
Intended for other use cases .

Best regards, Matthias


> -----Original Message-----
> From: David Holmes <david.holmes at oracle.com>
> Sent: Mittwoch, 26. September 2018 17:45
> To: Baesken, Matthias <matthias.baesken at sap.com>; 'hotspot-
> dev at openjdk.java.net' <hotspot-dev at openjdk.java.net>
> Subject: Re: AllocateHeapAt disabling on AIX
> 
> Hi Matthias,
> 
> On 26/09/2018 11:41 AM, Baesken, Matthias wrote:
> > Hello,  we want to disable the globals-flag  AllocateHeapAt on AIX  .
> > It currently does not really work   on this platform,  and there is no  current
> plan to support it   .
> >
> > My question :
> >
> > Should I  just add a check to argument.cpp  ?
> > Or should I use  the   constraint  function  feature for this ?
> 
> Do you want the flag to be non-existent or non-settable? What kind of
> error report do you want for the end user?
> 
> Thanks,
> David
> 
> > E.g.  add   a  constraint function  to  globals.hpp  and then do something like
> this ?
> >
> > JVMFlag::Error AllocateHeapAtConstraintFunc(ccstr value, bool verbose) {
> > #if defined(_AIX)
> >    return JVMFlag::VIOLATES_CONSTRAINT;
> > #endif
> >    return JVMFlag::SUCCESS;
> > }
> >
> >
> > To me the  current usages of the  constraint  functions do not look like they
> were intended for  platform-handling,  but for
> >     Checking  validity/sanity  of some flag values .
> >
> >
> > Thanks for your comments,  Matthias
> >