RFR(XS): 8154174: improve JitTester performance

[Igor Ignatyev]

Hi Anton,

looks good to me, thanks for doing that.

— Igor
> On Apr 14, 2016, at 6:30 AM, Anton Ivanov <anton.ivanov at oracle.com> wrote:
> 
> Hi,
> Please review small patch that improves JitTester performance
> 
> In current implementation JitTester has exception based logic, which is not good by itself, but changing this is quite expensive and there is simple way to decrease exception overhead - turn off stack trace in ProductionFailedException constructor ( this exception is created very often and stack trace is never need, as it only used to control program flow )
> Also small improvement was done in code that does deep copy of SymbolTable element ( Map iteration was rewritten to get rid of multiple redundant Map.get() which cost 0(1) only in average case and could be worse potentially )
> 
> Testing: local
> 
> webrev: http://cr.openjdk.java.net/~aaivanov/8154174/webrev
> bug: https://bugs.openjdk.java.net/browse/JDK-8154174
> 
> -- 
> Best regards,
> Anton Ivanov
>