RFR: 8319716: RISC-V: Add SHA-2 [v10]

[Robbin Ehn]

On Sat, 23 Dec 2023 03:06:30 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Robbin Ehn has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fixed lmul
>
> src/hotspot/cpu/riscv/stubGenerator_riscv.cpp line 3934:
> 
>> 3932:       //
>> 3933:       // e32/e64: vector of 32b/64b/4B/8B elements
>> 3934:       // m1: LMUL=1
> 
> This line of comment needs to be updated to reflect the latest changes.

Fixed

> src/hotspot/cpu/riscv/vm_version_riscv.cpp line 169:
> 
>> 167:     if (UseRVV) {
>> 168:       if (FLAG_IS_DEFAULT(UseSHA256Intrinsics)) {
>> 169:         FLAG_SET_DEFAULT(UseSHA256Intrinsics, true);
> 
> As the code comment in shared code indicates [1], there should be a dependency between these flags and `UseSHA`. But seems we are still lacking the necessary logic for that and `UseSHA` is always false [2]. We might need similar handling like our aarch64 counterpart [3].
> 
> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/runtime/globals.hpp#L342
> [2] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/riscv/vm_version_riscv.cpp#L151
> [3] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp#L323-L376

Fixed

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

PR Review Comment: https://git.openjdk.org/jdk/pull/16562#discussion_r1442604686
PR Review Comment: https://git.openjdk.org/jdk/pull/16562#discussion_r1442604860