RFR: 8304915: Create jdk.internal.util.Architecture enum and apply [v7]

[Glavo]

On Thu, 6 Apr 2023 20:24:27 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/util/Architecture.java line 100:
>> 
>>> 98:      */
>>> 99:     public static Architecture current() {
>>> 100:         return archValues[OperatingSystemProps.CURRENT_ARCH_ORDINAL];
>> 
>> I think the `Architecture ` is different from the `OperatingSystem`. There are ports of [other architectures](https://github.com/openjdk/jdk/blob/1d517afbd4547171ad6fb6a3356351c2554c8279/make/autoconf/platform.m4#L33-L188) (Including `MIPS64el`, `LoongArch64`, `SPARC v9`, etc) in the upstream.
>> 
>> Will hard coding architectures destroy these ports? Should a "OTHER" or "UNKNOWN" entry be added  to the enum to represent other architectures that are not of concern?
>
> There is no benefit to preemptively defining a full set of architectures; we only need those that are used in the OpenJDK runtime selection of options or parameters.
> The other and unknown cases can be handled in code using switch as `default` or for `if (xx) {} else {...}` in the else clause.
> Ports not supported the OpenJDK can add enum values and the corresponding static `isXXX()` methods if needed.
> 
> The template file used in the implementation could be renamed to be more agnostic to OS or arch.

I understand that there is no need to define enum entries for all architectures now, but the `current` method seems to cause crashes on other platforms. 

Even worse, `OperatingSystemProps` seems to be unable to compile on other architectures at all:

https://github.com/openjdk/jdk/blob/52ca4a70fc3de9e285964f9545ea8cd54e2d9924/src/java.base/share/classes/jdk/internal/util/OperatingSystemProps.java.template#L40

Does `Architecture` really need to be implemented as an enum? The value of this enum has never been used in this PR except for testing. I think perhaps just providing the isXXX methods is enough.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/13357#discussion_r1160242246