RFR XXS (8185826) HotSpot build failure with GCC 7.1.1

[Yasumasa Suenaga]

Hi Ioi,

Your change looks good.
I reviewed (OpenJDK name: ysuenaga).

Could you push this change?
(I cannot access JPRT)


Thanks,

Yasumasa


2017-08-04 14:12 GMT+09:00 David Holmes <david.holmes at oracle.com>:
> Hi Ioi,
>
> On 4/08/2017 2:50 PM, Ioi Lam wrote:
>>
>> On 8/3/17 7:00 PM, David Holmes wrote:
>>
>>> Hi Yasumasa,
>>>
>>> On 4/08/2017 10:49 AM, Yasumasa Suenaga wrote:
>>>>
>>>> Thanks Kim, David,
>>>>
>>>> I filed this issue to JBS and uploaded webrev. Could you review it?
>>>>
>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8185826/webrev.00/
>>>
>>>
>>> I'm still at a loss to understand how the current code even
>>> compiles/links at all with any version of the compiler. ??
>>>
>> Hi Yasumasa, thanks for noticing this.
>>
>> Sorry, it was my bug. I checked this in as part of JDK-8072061 on Tuesday.
>>
>> Apparently older C++ compilers are quite lenient when compiling template
>> declarations that aren't instantiated. Here's a test case:
>>
>> template <typename T> class X {
>>    static int size() {
>>      return align_size_up(byte_sizeof());
>>    }
>>    static int byte_sizeof() {
>>      return sizeof(T);
>>    }
>> };
>>
>> # from gcc 5.4:
>> $ gcc -c ~/t.cpp && echo $?
>> 0
>>
>> In our case, presumably, gcc will detect the error when an instantiated
>> Array<T> type access the size(int, int) method.
>
>
> Ah I see.
>
>> However, I added this function during my development, but didn't need it
>> after all. So this function was never referenced, so all of our existing
>> compilers never had a chance to generate an error for
>>
>> I removed this function and HotSpot built with no error.
>>
>> $ hg diff
>> diff -r 731370f39fcd src/share/vm/oops/array.hpp
>> --- a/src/share/vm/oops/array.hpp    Wed Aug 02 18:06:38 2017 -0700
>> +++ b/src/share/vm/oops/array.hpp    Thu Aug 03 21:47:41 2017 -0700
>> @@ -134,10 +134,6 @@
>>
>>       return (int)words;
>>     }
>> -  static int size(int length, int elm_byte_size) {
>> -    return align_size_up(byte_sizeof(length, elm_byte_size),
>> BytesPerWord) / BytesPerWord; // FIXME
>> -  }
>> -
>>     int size() {
>>       return size(_length);
>>     }
>>
>>
>> So I think proper fix is to just remove this function.
>
>
> Sounds good to me. Reviewed!
>
> Thanks,
> David
>
>> Thanks
>> - Ioi
>>
>>
>>
>>
>>> You removed a "// FIXME" comment - what was that referring to ??
>>>
>>> Thanks,
>>> David
>>>
>>>> I cannot access JPRT. So I need a sponsor.
>>>>
>>>>
>>>> Yasumasa
>>>>
>>>>
>>>>
>>>> 2017-08-04 9:08 GMT+09:00 Kim Barrett <kim.barrett at oracle.com>:
>>>>>>
>>>>>> On Aug 3, 2017, at 7:12 PM, David Holmes <david.holmes at oracle.com>
>>>>>> wrote:
>>>>>> I can't even see a definition of align_size_up - where is it coming
>>>>>> from ???
>>>>>
>>>>>
>>>>> It was recently removed.
>>>>>
>>>>> 8178499: Remove _ptr_ and _size_ infixes from align functions
>>>>>
>>
>