[aarch64-port-dev ] Fwd: RFR(xs): 8233019: java.lang.Class.isPrimitive() (C1) returns wrong result if Klass* is aligned to 32bit

[Thomas Stüfe]

Thanks Andrew!

On Mon, Nov 4, 2019, 18:22 Andrew Haley <aph at redhat.com> wrote:

> On 11/4/19 3:21 PM, Thomas Stüfe wrote:
> > could some aarch64 people please take a quick look at this small patch?
> >
> > The aarch64 part is really tiny, but I have no possibility to test this.
> >
> > Last webrev:
> >
> http://cr.openjdk.java.net/~stuefe/webrevs/8233019--c1-intrinsic-for-java.lang.class.isprimitive()-does-32bit-compare/webrev.01/webrev/
> > Issue: https://bugs.openjdk.java.net/browse/JDK-8233019
>
> Seems fine.
>
> Before:
>
>  ;;  block B0 [0, 4]
>   0x0000ffffa1d93f54:   ldr     x0, [x1, #80]               ; implicit
> exception: dispatches to 0x0000ffffa1d93f78
>   0x0000ffffa1d93f58:   cmp     w0, #0x0
>   0x0000ffffa1d93f5c:   cset    x0, eq  // eq = none
> ;*invokevirtual isPrimitive {reexecute=0 rethrow=0 return_oop=0}
>                                                             ; -
> IsPrimitiveTest::isPrimitive at 1 (line 4)
>
> After:
>
>  ;;  block B0 [0, 4]
>   0x0000ffff71dc75d4:   ldr     x0, [x1, #80]               ; implicit
> exception: dispatches to 0x0000ffff71dc75f8
>   0x0000ffff71dc75d8:   cmp     x0, #0x0
>   0x0000ffff71dc75dc:   cset    x0, eq  // eq = none
> ;*invokevirtual isPrimitive {reexecute=0 rethrow=0 return_oop=0}
>                                                            ; -
> IsPrimitiveTest::isPrimitive at 1 (line 4)
>
> i.e. the first test is "cmp w0, #0x0", the second is "cmp x0, #0x0".
> The first is a 32-bit comparison, the second 64-bit.
>
> --
> Andrew Haley  (he/him)
> Java Platform Lead Engineer
> Red Hat UK Ltd. <https://www.redhat.com>
> https://keybase.io/andrewhaley
> EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
>
>