RFR: 8186670: Implement _onSpinWait() intrinsic for AArch64 [v8]

[Evgeny Astigeevich]

On Tue, 28 Sep 2021 12:54:47 GMT, Andrew Dinn <adinn at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/onSpinWait/TestOnSpinWaitAArch64.java line 87:
>> 
>>> 85:     private static String getSpinWaitInstHex(String spinWaitInst) {
>>> 86:       if ("nop".equals(spinWaitInst)) {
>>> 87:           return "1f20 03d5";
>> 
>> I'm getting the following when running these tests:
>> STDERR:
>> java.lang.RuntimeException: Wrong instruction 1f20 03d5 count 0!
>>   -- expecting 7
>>         at compiler.onSpinWait.TestOnSpinWaitAArch64.checkOutput(TestOnSpinWaitAArch64.java:163)
>>         at compiler.onSpinWait.TestOnSpinWaitAArch64.main(TestOnSpinWaitAArch64.java:82)
>>         at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>>         at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
>>         at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>>         at java.base/java.lang.reflect.Method.invoke(Method.java:568)
>>         at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
>>         at java.base/java.lang.Thread.run(Thread.java:833)
>> 
>> I have hsdis installed as a matter of course, is the test written assuming hsdis is not present?
>
> Yes, currently it is assumed that hsdis is not present and hence that the disassembly produces hex insns. However, if you install hsdis as part of the build (as I always do) then these tests will fail.  It would really be better if the test looked for the correct hex insns or disassembled insns.

@adinn is correct. I am updating the test to support hsdis.

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PR: https://git.openjdk.java.net/jdk/pull/5562