[16] RFR(S): 8248398: Add diagnostic RepeatCompilation utility

[Nils Eliasson]

Thank you Tobias, Claes and Vladimir!

I got the suggestion from Patric to change to use unified logging 
instead of PrintCompilation. Are you ok with that?

Best regards,
Nils

On 2020-06-29 08:33, Tobias Hartmann wrote:
> Hi Nils,
>
> Looks good to me!
>
> In globals.hpp:543 there is an excess whitespace before "\".
>
> Best regards,
> Tobias
>
> On 26.06.20 16:48, Nils Eliasson wrote:
>> Hi,
>>
>> This is a diagnostic utility that was requested by Claes to enable better profiling of the compilers.
>>
>> This patch introduces the diagnostic flag RepeatCompilation.
>>
>> RepeatCompilation hold he number of times the compilation gets repeated without having the code
>> installed. RepeatCompilation = 0 is the default and means that only the regular compilation is done.
>> RepeatCompilation = 100 means that an extra 100 compilations are done but without installing the code.
>>
>> I have tried keeping the change small and non-intrusive, contained to the CompilerBroker (except the
>> boolean for disabling code install that is passed to the compilers).
>>
>> RepatCompilation works as a flag: "-XX:RepeatCompilation=100", a compile command:
>> "-XX:CompileCommand=option,*::toString,intx,RepeatCompilation,100"
>> and a compiler directive: "RepeatCompilation : 100".
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8248398
>> Webrev: http://cr.openjdk.java.net/~neliasso/8248398/webrev.04/
>>
>> Please review!
>>
>> Best regards,
>> Nils Eliasson
>>