On 12/23/11 03:31, Richard Guenther wrote:
On Thu, Dec 22, 2011 at 8:47 PM, Aldy Hernandez<al...@redhat.com> wrote:
The problem here is that with -fnon-call-exceptions, a memory dereference
may trap, but when we instrument the store, we have lost the landing pad
information.
One solution would be to move the EH information to the TM load/store
instrumentation builtins, but that doesn't get us around the fact that
libitm is not exception safe, and we have no mechanism for taking and
exception (and propagating it) in the middle of a transaction.
Richard has suggested that another alternative could be to support the
exception case for NULL, but non-null faulting memory references would still
cause a crash. In this case we would simply test for NULL at the start of
the accessors and explicitly throw the exception.
And yet a third alternative, is to disable the -fgnu-tm and
-fnon-call-exceptions combination. I have implemented this one, as I'd
rather have it not work, than work half-way.
Torvald, do you have any thoughts on the matter?
Attached patch for disabling the feature, if you both agree on this
approach.
I think this should be documented at the place -fgnu-tm is documented.
Richard.
I can certainly do this. I am however, waiting for the final approval.
It wasn't clear whether that was an approval from Richard Henderson,
or whether I should wait for an official ok.
OK for mainline?
