RFR: 8248238: Implementation of JEP: Windows AArch64 Support [v6]

[Chris Plummer]

On Thu, 24 Sep 2020 14:04:22 GMT, Monica Beckwith <mbeckwit at openjdk.org> wrote:

>> This is a continuation of https://mail.openjdk.java.net/pipermail/aarch64-port-dev/2020-August/009566.html
>>  
>> Changes since then:
>> * We've improved the write barrier as suggested by Andrew [1]
>> * The define-guards around R18 have been changed to `R18_RESERVED`. This will be enabled for Windows only for now but
>>   will be required for the upcoming macOS+Aarch64 [2] port as well.
>> * We've incorporated https://github.com/openjdk/jdk/pull/154 by @AntonKozlov in our PR for now and built the
>>   Windows-specific CPU feature detection on top of it.
>> 
>> [1] https://mail.openjdk.java.net/pipermail/aarch64-port-dev/2020-August/009597.html
>> [2] https://openjdk.java.net/jeps/8251280
>
> Monica Beckwith has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev
> excludes the unrelated changes brought in by the merge/rebase. The pull request contains 17 additional commits since
> the last revision:
>  - cleanup for 8253539: Remove unused JavaThread functions for set_last_Java_fp/pc
>  - cleanup for 8253457: Remove unimplemented register stack functions
>  - Merge remote-tracking branch 'upstream/master' into jdk-windows
>  - Update orderAccess_windows_aarch64.hpp
>    
>    changing from Acq-reL to Sequential Consistency to avoid compiler reordering when no ordering hints are provided
>  - 8248787: G1: Workaround MSVC bug
>    Reviewed-by:
>    Contributed-by: mbeckwit, luhenry, burban
>  - 8248670: Windows: Exception handling support on AArch64
>    Reviewed-by:
>    Contributed-by: mbeckwit, luhenry, burban
>  - 8248660: AArch64: Make _clear_cache and _nop portable
>    Summary: __builtin___clear_cache, etc.
>    Contributed-by: mbeckwit, luhenry, burban
>  - 8248659: AArch64: Extend CPU Feature detection
>    Reviewed-by:
>    Contributed-by: mbeckwit, luhenry, burban
>  - 8248656: Add Windows AArch64 platform support code
>    Reviewed-by:
>    Contributed-by: mbeckwit, luhenry, burban
>  - 8248498: Add build system support for Windows AArch64
>    Reviewed-by:
>    Contributed-by: mbeckwit, luhenry, burban
>  - ... and 7 more: https://git.openjdk.java.net/jdk/compare/ddd43bee...2b662010

I looked at changes to existing SA files. These changes look fine.

I did not look at the new aarch64 SA files other than the copyright section. I assume they are clones of the x64
versions with some symbolic renaming. If there is any more than that and you'd like me to have a look, let me know.

As for the copyright in the new SA files, I believe it is incorrect and needs to include Oracle. There are a number of
other non-SA files that are new and also have the same copyright issue.

I also looked at src/jdk.attach/windows/classes/sun/tools/attach/AttachProviderImpl.java. It looks fine except it needs
a copyright date update.

-------------

Changes requested by cjplummer (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/212