RFR: 8265702: ZGC on macOS/aarch64

[Stefan Karlsson]

On Wed, 21 Apr 2021 21:10:02 GMT, Per Liden <pliden at openjdk.org> wrote:

> This patch enables ZGC on macOS/aarch64. It does three things:
> 1) Enables building of ZGC on this platform.
> 2) Adds `os::processor_id()`, which for now always returns 0.
> 3) Fixes a WX issue in `OptoRuntime::handle_exception_C()`, where the stackwater mark might unnecessarily process a frame when the thread is in WXExec mode. In this case, the we're not touching any oops, so we don't need to process any frames.
> 
> Testing: Passes the same tests as macOS/x86_64 (with the exception of pre-existing issues unrelated to ZGC).

Marked as reviewed by stefank (Reviewer).

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

PR: https://git.openjdk.java.net/jdk/pull/3609