[9] RFR(S/M): 8166377: is_compiled_by_jvmci hot in some profiles - improve nmethod compiler type detection

[Vladimir Kozlov]

Can we move CompLevel, CompilerType and related code to 
abstractCompiler.hpp? Some #include dependencies may no allow it but we 
should try.

It is strange to have it in globalDefinitions.hpp.

Otherwise changes are good.

Thanks,
Vladimir

On 10/4/16 6:54 AM, Nils Eliasson wrote:
>
> Hi,
>
> Please review this change. It touches many files but is not complex.
>
> Description:
> We have seen a performance regression in some benchmarks where
> nmethod::is_compiled_by_jvmci() has been hot. That method is used is a
> workaround in CompiledMethod::is_deopt_entry(). The workaround remains
> for the moment, this fix makes it less costly.
>
> Summary:
> This fix removes the compiler reference from the codeblobs and instead
> performs the compiler type check on a constant, this removes a double
> dereference when checking the compiler. I also took the time to properly
> add the compiler types to the constructors.
>
>
> bugs: https://bugs.openjdk.java.net/browse/JDK-8166377
> webrev: http://cr.openjdk.java.net/~neliasso/8166377/
>
> Regards,
> Nils Eliasson