[aarch64-port-dev ] RFR: 8243339: AArch64: Obsolete UseBarriersForVolatile option

[Andrew Haley]

On 5/21/20 11:24 AM, Xiaohong Gong wrote:
> I'v created a new patch to add the condition when inserting "DMBs" before volatile
> load for C1/Interpreter.
> The updated webrev: http://cr.openjdk.java.net/~xgong/rfr/8243339/webrev.01/
>
> It adds a new function "is_c1_or_interpreter_only()" , which can decide whether
> C2/JVMCI is used. Besides, since AOT also uses Graal compiler as the codegen, it
> always return false if AOT mode is enabled.

Looks good to me, thanks.

As far as I remember, Graal does optimize volatile accesses to use
ldar/stlr, or at least it will do so in the future, so if we're using
AOT or JVMCI the safe thing to do is add the DMBs.

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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