URGENT RFR: 8041141: JDK9 emb build failure on PPC platform

[Andrew Hughes]

----- Original Message -----
> Hi Andrew,
> 
> On 12/06/2014 3:03 AM, Andrew Hughes wrote:
> > ----- Original Message -----
> >> http://cr.openjdk.java.net/~dholmes/8041141/webrev/
> >>
> >> The recent changes to convert warnings to errors didn't account for some
> >> type-punning warnings in our Embedded PPC build due to the use of
> >> strict-aliasing. Really we shouldn't be using strict-aliasing so this
> >> change (which for some reason is in the open flags.m4 file) brings ppc
> >> in-line with all other platforms and sets -fno-strict-aliasing
> >>
> >> I will be pushing this to jdk9/dev as we need this fixed immediately.
> >>
> >> Thanks,
> >> David
> >>
> >
> > Hi David,
> >
> > I just stumbled across this when trying to work out why we are seeing
> > aliasing
> > warnings in the demo code only on PPC builds. They get flagged by our build
> > process.
> > This exclusion of fno-strict-aliasing on PPC seems to date back to 7027910
> > in OpenJDK
> > 7, where we are seeing the warnings, and there seems to be no explanation
> > as to why
> > it was added in either the code or reviews.
> 
> It was copied from our internal build instructions. The new build
> unfortunately required it to be exposed in flags.m4.

Ah, ok.

> 
> > Given -fno-strict-aliasing is now being used on all architectures in 9, do
> > you think
> > it's ok to do the same in 7? I could also turn it off on the individual
> > files, but
> > this would duplicate the flag on other architectures and we may then get
> > more PPC-only
> > warnings in future.
> 
> I think it should be fine in principle. I'm not sure what the actual
> change in 7 would be.

Just this: http://icedtea.classpath.org/hg/release/icedtea7-forest-2.5/jdk/rev/925c4ace5635

I'll look at getting the change backported to 7 & 8 then.

> 
> David
> -----
> 
> > Thanks,
> >
> 

-- 
Andrew :)

Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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