[jdk19] RFR: 8288949: serviceability/jvmti/vthread/ContStackDepthTest/ContStackDepthTest.java failing [v3]

[Dean Long]

On Wed, 6 Jul 2022 08:56:49 GMT, Ron Pressler <rpressler at openjdk.org> wrote:

>> src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp line 1322:
>> 
>>> 1320: 
>>> 1321:     __ pop(rax); // return address
>>> 1322:     // Read interpreter arguments into registers (this is an ad-hoc i2c adapter)
>> 
>> If I understand this correctly, this allows you to avoid creating an interpreted frame.  Pretty clever!
>
> Yeah, it's a hand-rolled i2c adapter. I thought of just calling `gen_i2c_adapter` in place, but that would have required changing it. If we had two separate nmethods, we could rely on the standard i2c, but having two nmethods for a single Method didn't seem safe at this time. We can revisit later.

I don't think the interpreter version needs to be an nmethod.  It could be more like the intrinsics generated by TemplateInterpreterGenerator::generate_method_entry, but let's revisit after jdk19.

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PR: https://git.openjdk.org/jdk19/pull/66