RFR: JDK-8157141 & JDK-8166454: Solaris getisax(2) and meminfo(2) cleanup

[Alan Burlison]

On 01/10/2016 01:08, Kim Barrett wrote:

>> They are never going to change value, but if you'd prefer they weren't used let me know and I'll revert to the integer constants.
>
> I like the use of symbolic constants.  It’s the unnecessary assumptions about their values that I dislike.
>
> I’d prefer something like
>
>   const uint_t av_size = MAX2(AV_HW1_IDX, AV_HW2_IDX) + 1;
>   uint_t* av = alloca(av_size);
>   getisax(av, av_size);
>
> So av is known to be big enough to access the desired elements.

The values of AV_HW1_IDX and AV_HW2_IDX can't be changed without 
breaking binary compatibility, and we simply aren't ever going to do 
that. We can then assume the values of AV_HW1_IDX and AV_HW2_IDX known, 
namely 0 and 1 respectively, there's no point in comparing them. Plus 
if/when we get the 3rd capabilities word it will need changing anyway.

I've therefore changed the code to remove the alloca() call and be just:

// Extract valid instruction set extensions.
uint_t avs[AV_HW2_IDX + 1];
uint_t avn = getisax(avs, sizeof(avs));

webrev updated accordingly.

-- 
Alan Burlison
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