Preliminary RFR (L): 8001107: @Stable annotation for constant folding of lazily evaluated variables

[Vladimir Ivanov]

Chris, Vladimir, thank you.

Best regards,
Vladimir Ivanov

On 9/5/13 2:17 AM, Vladimir Kozlov wrote:
> +1
>
> Vladimir K
>
> On 9/4/13 12:00 PM, Christian Thalinger wrote:
>> Looks good.  -- Chris
>>
>> On Sep 4, 2013, at 2:56 AM, Vladimir Ivanov
>> <vladimir.x.ivanov at oracle.com> wrote:
>>
>>> FYI, I've updated [1] with proposed changes.
>>>
>>> Best regards,
>>> Vladimir Ivanov
>>>
>>> [1] http://cr.openjdk.java.net/~vlivanov/8001107/webrev.04
>>>
>>> On 9/4/13 1:20 AM, Vladimir Kozlov wrote:
>>>> On 9/3/13 2:04 PM, Vladimir Ivanov wrote:
>>>>> John,
>>>>>
>>>>> I'm fine with both options (add an assert or use
>>>>> element_value(index).as_char() in product).
>>>>>
>>>>> Vladimir K., what do you prefer?
>>>>
>>>> assert
>>>>
>>>> Vladimir K
>>>>
>>>>>
>>>>> Best regards,
>>>>> Vladimir Ivanov
>>>>>
>>>>> On 9/3/13 10:40 AM, John Rose wrote:
>>>>>> On Aug 29, 2013, at 4:57 PM, Vladimir Kozlov
>>>>>> <vladimir.kozlov at oracle.com
>>>>>> <mailto:vladimir.kozlov at oracle.com>> wrote:
>>>>>>
>>>>>>>>> ciTypeArray.cpp: why we need these changes?
>>>>>>>> I consider this as a cleanup. element_value(index).as_char()
>>>>>>>> performs
>>>>>>>> additional checks and it looks better (IMO, of course :-) ) than
>>>>>>>> get_typeArrayOop()->char_at(index).
>>>>>>>
>>>>>>> But element_value() is much more expensive! I don't like this
>>>>>>> change.
>>>>>>
>>>>>> The old char_at function works fine, but I think it needs an
>>>>>> assert that
>>>>>> the array being referenced is truly a char[] array.  The more
>>>>>> expensive
>>>>>> element_value function performs this check, so it is safer.  It is
>>>>>> also
>>>>>> helpful to prove (at least via an assert) that element_value is a
>>>>>> true
>>>>>> extension of char_at.
>>>>>>
>>>>>> If we don't like making char_at slightly more expensive (it
>>>>>> doesn't make
>>>>>> much difference!) then I suggest putting the call to element_value
>>>>>> into
>>>>>> the #ifdef ASSERT, as follows:
>>>>>>
>>>>>>      assert(index >= 0 && index < length(), "out of range");
>>>>>> !   jchar c = get_typeArrayOop()->char_at(index);
>>>>>> ! #ifdef ASSERT
>>>>>> !   jchar d = element_value(index).as_char();
>>>>>> !   assert(c == d, "");
>>>>>> ! #endif //ASSERT
>>>>>> !   return c;
>>>>>>    }
>>>>>>
>>>>>> — John
>>