RFR: 8286897: Loom: Cleanup x86_64 StubGenerator [v2]

[Vladimir Kozlov]

On Wed, 18 May 2022 05:55:31 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> src/hotspot/cpu/x86/stubGenerator_x86_64.cpp line 7460:
>> 
>>> 7458:     __ movptr(c_rarg0, r15_thread);
>>> 7459:     __ movptr(c_rarg1, rsp);
>>> 7460:     __ call_VM_leaf(Continuation::freeze_entry(), 2);
>> 
>> Was it bug to not set `c_rarg1`?  stubGenerator_aarch64.cpp has the same issue.
>
> Ah, so this one is little "behavioral" change. For some weird reason, the `__ movptr(c_rarg1, rsp);` used to be much earlier, between `start` and `the_pc`. I don't believe that's part of the frame setup. It looks like a copy-paste glitch from `generate_throw_exception`. So I just moved it here. No tests complain about this move.

Okay. I missed it in original place (too far away) and I thought it is new instruction.

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PR: https://git.openjdk.java.net/jdk/pull/8755