RFR: 8025692: Add trace to find out what methods are used at runtime.

[Yumin Qi]

HI, All

   After several round of codereviews and discussion, now the second 
version is at:
   http://cr.openjdk.java.net/~minqi/8025692/webrev02/

   The flag names changed:

   TraceMethodUsge => LogTouchedMethods
   PrintMethodUsageAtExit => PrintTouchedMethodsAtExit

   The two flags now are diagnostic flags.

    Also similar, there changed in related variable names.
    Also fixed a flaw which is not found during last round of review: 
append new TouchedMethodRecord to end of hash bucket list.

   Make change to interpreter method entry  generation(for both native 
and normal) to enable build_method_counter called. This is necessary 
since if run -Xint, the call will be skipped so our code will be skipped 
so no logging for touched methods.

   Added test case for jcmd: jcmd <pid> VM.print_touched_methods.

   Tests: JPRT, aurora default test suites (in progress).

Thanks
Yumin


On 3/26/2015 7:34 PM, Yumin Qi wrote:
> Please review:
>
> bug: https://bugs.openjdk.java.net/browse/JDK-8025692
> webrev: http://cr.openjdk.java.net/~minqi/8025692/webrev01/
>
> Summary: Add two flags to help list all java methods called in 
> runtime, this is also in product and can help CDS to rearrange methods 
> in shared archive to avoid loading infrequent methods into memory.
>
> Tests: vm.runtime.quick.testlist, JPRT
>
>
> Thanks
> Yumin
>
>