RFR(m): 8074552: SafeFetch32 and SafeFetchN do not work in error handling

[Thomas Stüfe]

Hi Severin,

thank you for fixing this!

In the future I know now who to ask if a change affects zero.

Thomas


On Thu, Mar 19, 2015 at 3:31 PM, Severin Gehwolf <sgehwolf at redhat.com>
wrote:

> On Thu, 2015-03-19 at 11:28 +0000, Andrew Dinn wrote:
> > On 19/03/15 09:35, Thomas Stüfe wrote:
> > > this may be the case. I do not know the zero port very good.
> > >
> > > SefeFetch handling needs support from both signal handler and access
> > > routines to ucontext_t (ucontext_set_pc(), ucontext_get_pc()). Both is
> > > missing.
> > >
> > > In theory it could be added, because doing so requires no assembly of
> any
> > > sorts. But it looks like the zero port avoids any technique which
> requires
> > > fiddling around with the ucontext_t in the signal handler to jump to a
> > > continuation point. This looks intentional and I do not want to
> introduce
> > > any code which breaks the intention of zero port.
> > >
> > > Of course, the other way would be just to disable the test for zero.
> > >
> > > What would be the right way?
>
> Thomas, I think the way to go is to skip both, the test and the new
> error handler feature for Zero. Since it is C++ interpreter only, it's
> OK to not have this extra info in hs_err.
>
> Shark, on the other hand, is likely different but I don't know much
> about it.
>
> > Coleen, thanks very much for checking to see if this fix causes an issue
> > for zero.
>
> +1, very much appreciated!
>
> I see that this has already been pushed[1]. I'll follow up with a fix
> for Zero shortly (current w-i-p patch attached).
>
> Cheers,
> Severin
>
> [1] http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/rev/3eb61269f421
>
> > Thomas, I have pointed the relevant Red Hat developers at this thread.
> > One of them should respond soon.
> >
> > regards,
> >
> >
> > Andrew Dinn
> > -----------
> > Senior Principal Software Engineer
> > Red Hat UK Ltd
> > Registered in UK and Wales under Company Registration No. 3798903
> > Directors: Michael Cunningham (USA), Matt Parson (USA), Charlie Peters
> > (USA), Michael O'Neill (Ireland)
> >
> >
>
>
>
>