[jdk11u-dev] RFR: 8254827: JVMCI: Enable it for Windows+AArch64 [v3]

[Andrew Haley]

On Tue, 5 Oct 2021 16:42:25 GMT, Reka Kovacs <rkovacs at openjdk.org> wrote:

>> Changes are almost identical to the original commit, only that JVMCI and Graal are enabled in `hotspot.m4` instead of `jvm-features.m4`.
>> 
>> Depends on #301.
>> 
>> Part of the Windows/AArch64 port.
>
> Reka Kovacs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:
> 
>   Backport 88ee973334e6a155719bd2486da73567d59a7f1e

src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot.aarch64/src/jdk/vm/ci/hotspot/aarch64/AArch64HotSpotRegisterConfig.java line 141:

> 139:     private static RegisterArray initAllocatable(Architecture arch, boolean reserveForHeapBase, boolean canUsePlatformRegister) {
> 140:         RegisterArray allRegisters = arch.getAvailableValueRegisters();
> 141:         Register[] registers = new Register[allRegisters.size() - reservedRegisters.size() - (reserveForHeapBase ? 1 : 0) - (!canUsePlatformRegister ? 1 : 0)];

This is confusing and complicated. If you set `platformRegister` to be either `r18` or `Register.None` depending on the OS, you don't need a separate boolean `canUsePlatformRegister`.

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PR: https://git.openjdk.java.net/jdk11u-dev/pull/307