RFR: 8290840: Refactor the "os" class [v5]

[David Holmes]

On Tue, 2 Aug 2022 07:07:54 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Please see [JDK-8290840](https://bugs.openjdk.org/browse/JDK-8290840) for the detailed proposal.
>> 
>> The `os` class, declared in os.hpp, forms the major part of the HotSpot porting interface. Its structure has gradually deteriorated over the years as new ports are created and new APIs are added.
>> 
>> This RFE tries to address the following:
>> 
>> - Clearly specify where a porting API should be declared and defined among the various `os*.cpp` and `os*.hpp` files.
>> - Avoid the inappropriate inclusion of OS-specific APIs (such as the `os::Linux class`) by platform-independent source files.
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fixed whitespace

Still seems okay to me.

src/hotspot/os_cpu/linux_ppc/os_linux_ppc.cpp line 520:

> 518: }
> 519: 
> 520: #if !defined(ABI_ELFv2)

I don't think many people will be able to map this to any specific platform. At a minimum some comment is needed to explain this.

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Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9600