[master] RFR: Fix loading Klass* in C1 on AArch64

[Roman Kennke]

On Fri, 21 Jan 2022 17:50:45 GMT, Andrew Haley <aph at openjdk.org> wrote:

> > ```
> > 1. If res is allocated in r0 we don't have a problem at all, and don't need to do anything.
> > 
> > 2. Else, I swap r0 and res. This preserves the original contents of r0 in res, which will be preserved around the call. This frees r0 for use as argument and result register.
> > ```
> 
> Why will res be preserved around the call? That's the part I don't get.

Because I implemented it that way (just like most other runtime call stubs):
https://github.com/openjdk/lilliput/blob/a9ec867aea4d665a1fc85f51bdb7586a575fcdcf/src/hotspot/cpu/aarch64/c1_Runtime1_aarch64.cpp#L725

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PR: https://git.openjdk.java.net/lilliput/pull/34