[ping] RFR(S): 8156992: [ppc] Implement template interpreter stack overflow checks as on x86/sparc.

[Lindenmaier, Goetz]

Hi David, 

well, yes, Dean had similar questions.
X86/sparc load stack_base and stack_size, compute stack_end and then add the
Max(shadow, quard). All in assembly in the template interpreter prolog.  On ppc,
we load it from the precomputed field stackoverflow_limit.  The value in that field
differed from what x86/sparc computed, which is the error I want to fix here. 
I adapted the drawing to the change of that field.

Best regards,
  Goetz



> -----Original Message-----
> From: David Holmes [mailto:david.holmes at oracle.com]
> Sent: Donnerstag, 26. Mai 2016 00:36
> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; hotspot-runtime-
> dev at openjdk.java.net
> Subject: Re: [ping] RFR(S): 8156992: [ppc] Implement template interpreter
> stack overflow checks as on x86/sparc.
> 
> Hi Goetz,
> 
> I know you were having discussions with Dean in relation to this but I
> really don't understand the change to the diagram in thread.hpp nor the
> change to the definition of stackoverflow_limit. To me the limit has to
> be the sum of the guard zone and shadow zone. With your MAX change the
> diagram doesn't even make sense AFAICS.
> 
> ??
> 
> David
> 
> On 25/05/2016 6:07 PM, Lindenmaier, Goetz wrote:
> > Hi,
> >
> > could someone else have a look at this change?  I need a reviewer, please.
> > I also please need a sponsor.
> >
> > Best regards,
> >   Goetz.
> >
> >> -----Original Message-----
> >> From: Lindenmaier, Goetz
> >> Sent: Mittwoch, 18. Mai 2016 12:02
> >> To: hotspot-runtime-dev at openjdk.java.net
> >> Subject: RFR(S): 8156992: [ppc] Implement template interpreter stack
> >> overflow checks as on x86/sparc.
> >>
> >> Hi,
> >>
> >> When porting the template interpreter, we implemented a different
> >> approach to
> >> Stack overflow handling.  See also the detailed description in the Jira bug.
> >>
> >> This change implements the stack overflow check as on x86/sparc.
> >> It requires simple shared changes, but only to code only used on ppc.
> >> The changes should not affect the other platforms.
> >>
> >> Please review this change. I please need a sponsor.
> >> http://cr.openjdk.java.net/~goetz/wr16/8156922-
> ppcStackFix/webrev.01/
> >>
> >> Best regards,
> >>   Goetz.
> >