RFR: 8291302: ARM32: nmethod entry barriers support [v2]

[Aleksei Voitylov]

On Wed, 30 Nov 2022 21:01:04 GMT, Erik Österlund <eosterlund at openjdk.org> wrote:

>> Aleksei Voitylov has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   save float registers
>
> When you call the nmethod entry barrier slow path, floating point arguments are live, but can get clobbered by the C++ runtime. You need to save them. That's probably why you can't print in the slow path without crashing.

@fisk @reinrich Thank you for your suggestions. This iteration saves floating registers and can successfully log deoptimization. I'd prefer to keep the code in line with the same code for other ports and not carve out memory barriers by hand, if @reinrich would agree. This also allows a more straightforward port for additional GCs in the future, should there be any demand.

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PR: https://git.openjdk.org/jdk/pull/11442