RFR (S) 8140650: Method::is_accessor should cover getters and setters for all types

[Coleen Phillimore]

Our emails crossed.   This change looks good.  I don't know how 
necessary the Zero TODO is but the comment is fine.

Coleen

On 11/5/15 3:16 PM, Aleksey Shipilev wrote:
> Ah, no, the CallNode::may_modify polls is_accessor only for boxed
> instances, so there are no setters in Java code. Still, we should check
> for getters there explicitly, and the getter/setter split is sensible in
> Method API anyhow.
>
> New webrev:
>    http://cr.openjdk.java.net/~shade/8140650/webrev.02/
>
> Re-spinning RBT for sanity.
>
> Thanks,
> -Aleksey
>
> On 11/05/2015 10:45 PM, Aleksey Shipilev wrote:
>> Thanks, Coleen!
>>
>> The tricky part is that compilers poll Method::is_accessor via:
>>
>>   bool ciMethod::is_accessor    () const {
>>     FETCH_FLAG_FROM_VM(is_accessor);
>>   }
>>
>> #define FETCH_FLAG_FROM_VM(flag_accessor) { \
>>    check_is_loaded(); \
>>    VM_ENTRY_MARK; \
>>    return get_Method()->flag_accessor(); \
>> }
>>
>> ...which may be opaque for IDEs, when you look for usages. I found that
>> a text search for "is_accessor" yields only positive matches.
>>
>> *Actually*, now that I read the code again, there is a suspicious use in
>> CallNode::may_modify:
>>
>>        if (meth->is_accessor()) {
>>          return false;
>>        }
>>
>> This seems to break if is_accessor accepts setters. Let me split the
>> is_accessor into is_getter/is_setter and re-run tests. If you spot other
>> problems in the patch, let me know.
>>
>> Thanks,
>> -Aleksey
>>
>> On 11/05/2015 08:34 PM, Coleen Phillimore wrote:
>>> I am planning on reviewing this but I haven't had time.  And I'm trying
>>> to build Zero for a different reason.  I would be pretty unhappy if it
>>> broke Zero and would like it to not do that.  I haven't had a chance to
>>> read all of this yet.  I thought is_accessor was only for Zero so I
>>> guess I have to read more why this is getting changed.  I will try to
>>> get to it today.
>>>
>>> Thanks,
>>> Coleen
>>>
>>> On 11/5/15 12:24 PM, Aleksey Shipilev wrote:
>>>> On 11/05/2015 07:59 PM, Vladimir Ivanov wrote:
>>>>>>> If there's an RFE filed and Zero maintainers promise to fix it in a
>>>>>>> prompt manner, I'm fine with what you proposed.
>>>>>> Yeah, that's the plan.
>>>>>>
>>>>>>> Also, I had an idea: why don't you move is_simple_accessor() from
>>>>>>> Method
>>>>>>> to some Zero-specific location? I don't see any value in keeping it in
>>>>>>> Method.
>>>>>> That's an interesting trick, but I think it will cause more harm:
>>>>>> shared
>>>>>> interpreter.cpp would have to know about that Zero-specific method, or
>>>>>> otherwise intercept "too wide" accessor shape and narrow it down before
>>>>>> it reaches Zero. Therefore, I believe is_simple_accessor is the lesser
>>>>>> evil.
>>>>> Ok. Looks good then.
>>>> Thanks for taking time to review, Vladimir! I'll count that as the
>>>> review from the compiler side.
>>>>
>>>> I think we still need a review from the runtime side. Folks? For the
>>>> record, we are discussing this change:
>>>>     http://cr.openjdk.java.net/~shade/8140650/webrev.01/
>>>>
>>>> The patch passes JPRT, RBT (hotspot_all), and the new regression test.
>>>>
>>>> Thanks,
>>>> -Aleksey
>>>>
>>>>
>>
>