RFR(S): 8160064: StackWalker implementation added logging option without using UL

[Coleen Phillimore]

(including Mandy, Brent and Daniel)

Rachel,

This looks good.  I have a couple of minor comments

http://cr.openjdk.java.net/~rprotacio/8160064/src/share/vm/prims/stackwalk.cpp.udiff.html

+ if (log_is_enabled(Trace, stackwalk)) {
+ ResourceMark rm;
+ outputStream* st = Log(stackwalk)::trace_stream();
+ st->print(" hidden method: ");
+ method->print_short_name(st);
+ st->cr();
          }

Do you have to ask if the log is enabled here and the other place? (I 
added it in this snippet).   I think it's tested implicitly when it 
creates the trace_stream() but since you have a {} block anyway, it 
seems clearer to test it.   Does method->print_stream(st) do nothing if 
the logging isn't enabled?

Also since THREAD is available, can you make ResourceMark rm(THREAD); 
take the THREAD argument in both places?

The test looks great.

Thanks,
Coleen

On 9/27/16 3:47 PM, Rachel Protacio wrote:
> Hi,
>
> Please review this small fix correcting the StackWalker print output 
> mechanism by moving it to Unified Logging. Includes a new jtreg test, 
> and passes JPRT.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8160064
> Open webrev: http://cr.openjdk.java.net/~rprotacio/8160064/
>
> Thank you!
> Rachel