Integrated: 8292638: x86: Improve scratch register handling in VM stubs

[Vladimir Ivanov]

On Thu, 18 Aug 2022 21:47:59 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> (PR depends on #9923.)
> 
> Constants which reside outside code cache are not guaranteed to be reachable in
> RIP-relative addressing mode from stub code, but absolute addressing mode requires a
> scratch register.
> 
> Provide a scratch register to ensure constants are reachable irrespective of
> process memory layout. 
> 
> Make scratch register usage explicit to make possible conflicts with surrounding stub code explicit.
> 
> Testing:
> - [x] hs-tier1 - hs-tier4
> - [x] x86_32 hotspot build

This pull request has now been integrated.

Changeset: f3be6731
Author:    Vladimir Ivanov <vlivanov at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/f3be6731d3fa4fb1b7fc42c5bcbe6a64a50eaf42
Stats:     583 lines in 14 files changed: 76 ins; 212 del; 295 mod

8292638: x86: Improve scratch register handling in VM stubs

Co-authored-by: Aleksey Shipilev <shade at openjdk.org>
Reviewed-by: kvn, shade

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

PR: https://git.openjdk.org/jdk/pull/9932