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

Severin Gehwolf sgehwolf at redhat.com
Thu Mar 19 14:31:32 UTC 2015

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).


[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)

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