RFR: 8321542: C2: Missing ChaCha20 stub for x86_32 leads to crashes

[Aleksey Shipilev]

On Tue, 12 Dec 2023 08:53:35 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> This fix corrects an oversight in the ChaCha20 intrinsics delivered by JDK-8247645.  An ifdef guard is now part of the x86 ChaCha20 intrinsics code which disables them by default on 32-bit platforms, as this architecture was not part of the feature delivery.
>
> src/hotspot/cpu/x86/vm_version_x86.cpp line 1152:
> 
>> 1150:   // No support currently for ChaCha20 intrinsics on 32-bit platforms
>> 1151:   if (UseChaCha20Intrinsics) {
>> 1152:       warning("Support for ChaCha20 intrinsics not available on this CPU.");
> 
> Maybe we can adapt the message to follow the convention of the other warning messages for intrinsics like AES
> https://github.com/openjdk/jdk/blob/2611a49ea13ee7a07f22692c3a4b32856ec5898f/src/hotspot/cpu/x86/vm_version_x86.cpp#L1062-L1065
> or CRC32C
> https://github.com/openjdk/jdk/blob/2611a49ea13ee7a07f22692c3a4b32856ec5898f/src/hotspot/cpu/x86/vm_version_x86.cpp#L1116-L1118
> 
> Suggestion:
> 
>       warning("ChaCha20 intrinsics are not available on this CPU.");
> 
> 
> Though I see that not all existing warning messages are consistent.
> 
> Anyway, the bailout looks good to me.

+1 on changing the message to "ChaCha20 intrinsics are not available on this CPU."

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

PR Review Comment: https://git.openjdk.org/jdk/pull/17072#discussion_r1423706642