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

[Coleen Phillimore]

Thank you for telling me where this is.  I would have had to grep around 
for too long.

On 11/5/15 2:45 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.

I can build Zero now, so I'll try this patch in the meantime.

Coleen
>
> 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
>>>
>>>
>