RFR: Add function entry/exit instruments for aarch64

[Arthur Eubanks]

On Thu, 30 Apr 2020 02:10:25 GMT, Jie He <github.com+10233373+jhe33 at openjdk.org> wrote:

>> The commit LGTM, but I have some questions about your comment.
>> 
>> 1) You mentioned generate_native_entry, but I don't see that in the commit anywhere.
>> 2) I think generate_native_wrapper is necessary to make tests like RacyNativeLoopTest.java pass, I'd be surprised if it
>> wasn't necessary.
>
> @aeubanks thanks for review.
> 1, I list generate_native_entry in commit msg because I think the generate_native_entry is the real   entry in JVM we
> want to instrument, which will call jvmti interface notify_method_entry/exit.
> 2, I was just wondering which case will go generate_native_wrapper, thus, I removed the instruments in
> generate_native_wrapper, but all cases still passed. as for RacyNativeLoopTest.java, I add a  breakpoint (int 3) before
> tsan instruments in generate_native_wrapper, it couldn't stop the execution. but the breakpoint in
> generate_native_entry could.

Hmm interesting...
If that's the case then going with your proposed changes is fine in a future commit. But I'll sponsor this to unblock
for now.

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PR: https://git.openjdk.java.net/tsan/pull/7