RFR: 8276799: Implementation of JEP 422: Linux/RISC-V Port [v2]

[David Holmes]

On Tue, 22 Mar 2022 12:08:01 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> make/autoconf/libraries.m4 line 152:
>> 
>>> 150:   fi
>>> 151: 
>>> 152:   # Programs which use C11 or C++11 atomics, like #include <atomic>,
>> 
>> Use of C++ atomics is not allowed in hotspot code base. See the style guide:
>> https://github.com/openjdk/jdk/blob/master/doc/hotspot-style.md
>> 
>> That said, I don't see any actual use of C++ atomics. ??
>
> I think the old code comment here is a bit too general. It does not mean we introduce any use of C++ atomics here.
> The fact is that RISC-V only has word-sized atomics, it requries libatomic where other common architectures do not [1].
> So atomic support would require explicit linking against -latomic on RISC-V. Otherwise we got build errors like:

New comment looks good - thanks for clarifying.

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PR: https://git.openjdk.java.net/jdk/pull/6294