RFR: 8249945: Improve ARRAY_SIZE()

[Kim Barrett]

> On Jul 23, 2020, at 11:09 AM, Lois Foltan <lois.foltan at oracle.com> wrote:
> 
> On 7/23/2020 3:31 AM, Kim Barrett wrote:
>> Please review this reimplementation of the ARRAY_SIZE() macro.  The
>> new implementation rejects pointer types instead of quietly returning
>> the wrong value; see the CR for more details.
>> 
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8249945
>> 
>> Webrev:
>> https://cr.openjdk.java.net/~kbarrett/8249945/open.00/
>> 
>> Testing:
>> mach5 tier1
>> 
> 
> Hi Kim,
> 
> Looks good.

Thanks.

>  For my own understanding, is there any value in adding a "const" in front of T in the template?  Such as
> 
> template<typename T, size_t N> char (&array_size_impl(const T (&)[N]))[N];
> 
> Thanks,
> Lois

I think it doesn’t matter; if the argument is const, the deduced T will be const qualified.  But we don’t care
about the details of the deduced T at all.  The last of the new gtest checks uses a const array argument.