RFR: 8254072: AArch64: Get rid of --disable-warnings-as-errors on Windows+ARM64 build [v2]

[Bernhard Urban-Forster]

On Thu, 15 Oct 2020 09:57:14 GMT, Andrew Haley <aph at openjdk.org> wrote:

> Fine, but please assert JavaThread::stack_shadow_zone_size() == (int)JavaThread::stack_shadow_zone_size().

Done.

> Adding casts to shut up compilers is a very risky business, because often (if not in this case) the programmer doesn't
> understand the code well, and sprinkles casts everywhere. But casts disable compile-time type checking, and this leads
> to risks for future maintainability.

Full ACK and I appreciate your comments on this!


> I wonder if we should fix it in a better way, and use something like
> this in the future for all compiler warnings:
> 
> ```
> template <typename T1, typename T2>
> T1 checked_cast(T2 thing) {
>   T1 result = static_cast<T1>(thing);
>   guarantee(static_cast<T2>(result) == thing, "must be");
>   return result;
> }
> ```
> 
> I know this is additional work, but I promise we'll never need to have this conversation again.

This sounds like a great idea to me. I assume it doesn't fit into the scope of this PR, therefore I've created
[JDK-8254856](https://bugs.openjdk.java.net/browse/JDK-8254856) to track it.

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PR: https://git.openjdk.java.net/jdk/pull/530