RFR: 8297830: aarch64: Make Address a descriminated union internally

[Andrew Haley]

On Wed, 30 Nov 2022 11:13:35 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this change to the aarch64 Address class.  It now uses an
> internal union, separating the literal and nonliteral cases.
> 
> This avoids leaving some fields uninitialized or initializing them to dummy
> values.  It also reduces the size of the Address class somewhat, though it's
> unclear whether that makes any noticeable difference.
> 
> Testing:
> mach5 tier1 for linux-aarch64 and macosx-aarch64
> mach5 tier2-5 for linux-aarch64

OK, thanks. It does seem to me a bit like moving the furniture around, but I have to admit it's an improvement. :-)

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Marked as reviewed by aph (Reviewer).

PR: https://git.openjdk.org/jdk/pull/11429