RFR(S): 8029351: assert(bt != T_OBJECT) failed: Guard is incorrect in VM:defmeth

[David Chase]

revised webrev: http://cr.openjdk.java.net/~drchase/8029351/webrev.02/

tested with jtreg and ute-vm.quick.testlist and 1000 repetitions of defmeth.

Turned out that there was no need to add a new method, there was ALREADY
a method that did almost what we want, and I added asserts at the use site
to ensure that the allegedly irrelevant difference was actually irrelevant.
(And it should have caused catastrophe before anyway if it was not irrelevant.)

David

On 2013-12-09, at 12:58 PM, David Chase <david.r.chase at oracle.com> wrote:

> 
> On 2013-12-09, at 11:28 AM, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:
>>> So is including them ALSO safe, since they should never occur?
>>> I'd prefer to use an existing "are you an object" code rather than inventing another one.
>>> I could also insert asserts that those two cases are not leaking through.
>> 
>> Yes, these two tags are also safe and true.   They might be expected in other call sites (now or in the future), so don't add asserts.
> 
> Ugh, before I saw your reply, I added them and have been testing.
> 
> Where I put the asserts, if the _index cases had leaked through in the past,
> would have been interesting, because they would have been treated as not-objects,
> which I think leads to downstream evil (e.g., infinite loops in the VM).
> So for now they are there, and for now they have not caused any problems,
> testing with defmeth, jtreg, and now I'm vm.quick.testlist.
> 
> Do you think that's okay, or should I remove the asserts?  That would only make
> the tests I'm running less likely to fail, and have no effect on the release build anyway.
> 
> David
> 

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