RFR(S): 8161379: @CallerSensitive methods should be forcefully inlined to get Reflection.getCallerClass optimization

[Christian Thalinger]

Why are you not setting the _force_inline bit on @CallerSensitive?  It would be less intrusive and more global so other compilers would pick it up as well.

> On Jul 15, 2016, at 2:12 PM, Claes Redestad <claes.redestad at oracle.com> wrote:
> 
> Hi,
> 
> Aleksey and I would like to contribute this patch which change the
> inlining policy to treat @CallerSensitive as it would
> @ForceSensitive.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8161379
> Webrev: http://cr.openjdk.java.net/~redestad/8161379/webrev.01/
> 
> The issue is that the JNI call behind Reflection.getCallerClass() is
> very expensive compared to the C2 intrinsic. This shows up in various
> microbenchmarks stress-testing reflection, method handle lookup etc,
> and can be linked to a number of intermittent regressions we see appear
> in various benchmarks.
> 
> See the bug for more information.
> 
> Testing: JPRT -testset hotspot, RBT hotspot-nightly-compiler
> 
> Thanks!
> 
> /Claes