RFR: 8218675: Reduce verification overhead in ClassFileParser

[Claes Redestad]

On 2019-02-11 12:25, David Holmes wrote:
>>>
>>
>> If you were just questioning the performance results, GCC does compile
>> the switch prelude in this method to a quick range check:
>>
>> sub $0x2e,%ecx  // 2e is '.', the lowest character
>> cmp $0x2d,%cl   // 2e + 2d is '[', the highest character
>> ja ...
> 
> Okay that's what I was wondering. But seems very compiler specific - are 
> they all this clever or does the new code only work better on some 
> platforms?

I don't have the tools or know-how to verify at this level of
granularity on other platforms (I'd of course be delighted to learn) but
our set of platform independent startup tests are not indicating
anything but improvements by this patch as a whole, which seemed like
enough verification to me.

/Claes