RFR: 8261071: AArch64: Refactor interpreter native wrappers

[Andrew Haley]

On Thu, 4 Feb 2021 22:01:34 GMT, Anton Kozlov <akozlov at openjdk.org> wrote:

> Please review refactoring of interpreter signature handlers on aarch64. The main objective is to prepare for the new calling convention of macOS/AArch64, although this patch brings nothing from the new convention.
> 
> Tested with signature stress tests and tier1 on Linux/AArch64.
> 
> I have stared with a single function implementing SlowSignatureHandler (https://github.com/openjdk/jdk/commit/5ef1bd15c3bb174f4aed5e358d1ce2fff2846858#diff-1ff58ce70aeea7e9842d34e8d8fd9c94dd91182999d455618b2a171efd8f742cR164). The single function was compact but obscure. I was shuffling it until I eventually came to something similar of the initial approach with few pieces abstracted away.
> 
> The most notable changes in the final version should be
> * we count only parameters passed in registers
> * ldrw/strw are used to pass via stack in SignatureHandlerGenerator::pass_int

Thanks, that looks way better. Are all platform differences handled by Interpreter::local_offset_in_bytes() ?

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PR: https://git.openjdk.java.net/jdk/pull/2413