RFR: 8266074: Vtable-based CHA implementation

[Vladimir Kozlov]

On Fri, 30 Apr 2021 19:34:40 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/cha/StrengthReduceInterfaceCall.java line 35:
>> 
>>> 33:  *
>>> 34:  * @run main/othervm -Xbootclasspath/a:. -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions
>>> 35:  *                   -XX:+UseVtableBasedCHA
>> 
>> `UseVtableBasedCHA` is `true` by default. May be duplicate these `runs` for both cases: on and off.
>
> The test assumes `UseVtableBasedCHA` is on and some of the assertions it makes fail with `-XX:-UseVtableBasedCHA`. So, it would require all the changes in the test logic have to be guarded by a check whether UseVtableBasedCHA is on or off.
> 
> Considering `UseVtableBasedCHA` is turned on by default in the PR, I don't see much value in complicating the test.

So only new implementation is tested with these changes in test. Got it. May be use:
`@requires vm.opt.final.UseVtableBasedCHA == true`

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PR: https://git.openjdk.java.net/jdk/pull/3727