RFR(S): AArch64: float point register corruption in ZBarrierSetAssembler::load_at
aph at redhat.com
Fri Jun 21 13:07:12 UTC 2019
On 6/21/19 10:32 AM, Stuart Monteith wrote:
> Apologies - sent prematurely.
> The interpreter passes rscratch1, which ultimately ends up in load_at.
> The first thing you'll hit is a call from the interpreter.
> 888 // Get mirror and store it in the frame as GC root for this Method*
> 889 __ load_mirror(rscratch1, rmethod);
> 890 __ stp(rscratch1, zr, Address(sp, 4 * wordSize));
Ah, yes. The interpreter has its own rules. So the problem is not that
rscratch1 is live across the call but that it's actually used as a
So how to fix it? There's no need to use scratch1 here, so we could
assert that scratch registers aren't used as args to load_at or make
load_at suitably defensive when it happens.
Andrew Haley (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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