[2.3 BRANCH]: gstabs issue

[Andrew Hughes]

----- Original Message -----
> 
> 
> ----- Original Message -----
> > On 08/06/2012 07:09 PM, Andrew Hughes wrote:
> > > ----- Original Message -----
> > >> On 08/06/2012 05:16 PM, Andrew Hughes wrote:
> > >>> ----- Original Message -----
> > >>>> On 08/06/2012 02:42 PM, Andrew Hughes wrote:
> > >>>>> There was a regression with DEBUG_BINARIES which resulted in
> > >>>>> some
> > >>>>> architectures
> > >>>>> (x86, SPARC, etc.) producing STABS debug information rather
> > >>>>> than
> > >>>>> DWARF.
> > >>>>>
> > >>>>> The fix for this is now in OpenJDK8 and IcedTea7 HEAD:
> > >>>>>
> > >>>>> http://hg.openjdk.java.net/icedtea/jdk7/hotspot/rev/c5430c659d54
> > >>>>>
> > >>>>> Ok to backport this to the 2.3 forest?
> > >>>>
> > >>>> It's very hard to understand what is supposed to be happening.
> > >>>>  I
> > >>>> think it means that ia64, amd64, arm, ppc get DWARF debug
> > >>>> info,
> > >>>> but
> > >>>> x86/32 and others get STABS.  But this makes no sense at all:
> > >>>> STABS
> > >>>> is not appropriate for x86/32 or any other Linux target
> > >>>> AFAIAA.
> > >>>
> > >>> No, that's what's happening now without this patch.  This patch
> > >>> corrects the behaviour so that DEBUG_BINARIES again takes
> > >>> precedence
> > >>> and applies "-g" in all cases (no "-gstabs") whatever the
> > >>> architecture or build type (fastdebug/debug/product).  It's
> > >>> hard
> > >>> to
> > >>> see because the patch is moving the previous lines inside an
> > >>> else
> > >>> block, which is only evaluated if DEBUG_BINARIES is not equal
> > >>> to
> > >>> true.
> > >>
> > >> OK, so it's still wrong if DEBUG_BINARIES is off, but it's only
> > >> wrong
> > >> on hosts other than ia64, amd64, arm and ppc.
> > > 
> > > "Wrong" for us yes.
> > 
> > Well, it results in a grossly degraded debug experience for
> > everyone.
> > I suspect that internally the HotSpot team do almost all of their
> > debugging in debug builds anyway.
> 
> Maybe, but all of them use stabs on x86.  My reading of that thread
> is that
> Coleen would like to see the back of them too, but Daniel won't
> unless there's
> enough payoff vs. the size increase:
> 
> http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2012-August/004184.html
> 
> > 
> > > It's what Oracle intended and still do for the time being.
> > 
> > > But we need what is a regression for us fixed ASAP, hence this
> > > interim patch,
> > > rather than waiting for Oracle to make their minds up, especially
> > > if they
> > > decide to stick with STABS for whatever reason.
> > 
> > OK, true enough, but we need to make sure that this never affects
> > us
> > again.
> > 
> > Andrew.
> > 
> > 
> > 
> 

So is this ok to go in 2.3?  Presumably 2.2 suffers as well (I believe that's where
we hit it)?

Thanks,
-- 
Andrew :)

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

PGP Key: 248BDC07 (https://keys.indymedia.org/)
Fingerprint = EC5A 1F5E C0AD 1D15 8F1F  8F91 3B96 A578 248B DC07