RFR: 8252505: C1/C2 compiler support for blackholes [v17]

[Aleksey Shipilev]

On Thu, 3 Dec 2020 12:07:48 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Print Blackhole format
>
> src/hotspot/share/opto/memnode.cpp line 3471:
> 
>> 3469:         st->print(", ");
>> 3470:       }
>> 3471:       char buf[128];
> 
> I'd introduce `PhaseRegAlloc::dump_register(Node*,outputStream*)` overload and put these 3 lines there. 
> 
> Then ADLC-generated code can be migrated to it later.

That refactoring would make sense, but maybe as separate PR that does everything at once? So that we don't introduce changeset dependencies.

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PR: https://git.openjdk.java.net/jdk/pull/1203