* [Patch, Gas, AArch64][0/1] Fix diagnostics for exclusive load/stores and reclassify Armv8.7-A ST/LD64 Atomics.
@ 2021-03-15 13:00 Tejas Belagod
2021-04-06 15:36 ` Nick Clifton
0 siblings, 1 reply; 4+ messages in thread
From: Tejas Belagod @ 2021-03-15 13:00 UTC (permalink / raw)
To: binutils
Hi,
Following upstream pointing out some inconsistencies in diagnostics,
https://sourceware.org/pipermail/binutils/2021-February/115356.html
attached is a patch set that fixes the issues. I believe a combination of two patches mainly contributed to these bugs:
https://sourceware.org/pipermail/binutils/2020-November/113961.html
https://sourceware.org/pipermail/binutils/2018-June/103322.html
A summary of what this patch set fixes:
For instructions
STXR w0,x2,[x0]
STLXR w0,x2,[x0]
The warning we emit currently is misleading:
t.s:9: Warning: unpredictable: identical transfer and status registers --`stlxr w0,x2,[x0]'
t.s:10: Warning: unpredictable: identical transfer and status registers --`stxr w0,x2,[x0]'
it ought to be:
t.s:9: Warning: unpredictable: identical base and status registers --`stlxr w0,x2,[x0]'
t.s:10: Warning: unpredictable: identical base and status registers --`stxr w0,x2,[x0]'
For instructions:
ldaxp x0,x0,[x0]
ldxp x0,x0,[x0]
The warning we emit is incorrect
t.s:11: Warning: unpredictable: identical transfer and status registers --`ldaxp x0,x0,[x0]'
t.s:12: Warning: unpredictable: identical transfer and status registers --`ldxp x0,x0,[x0]'
it ought to be:
Warning: unpredictable load of register pair -- `ldaxp x0,x0,[x0]'
Warning: unpredictable load of register pair -- `ldxp x0,x0,[x0]'
For instructions
stlxp w0, x2, x2, [x0]
stxp w0, x2, x2, [x0]
We don't emit any warning when it ought to be:
t.s:13: Warning: unpredictable: identical base and status registers --`stlxp w0,x2,x2,[x0]'
t.s:14: Warning: unpredictable: identical base and status registers --`stxp w0,x2,x2,[x0]'
For instructions:
st64bv x0, x2, [x0]
st64bv x2, x0, [x0]
We incorrectly warn when its not necessary. This is because we classify them incorrectly as ldstexcl when it should be lse_atomics in the opcode table. The incorrect classification makes it pick up the warnings from warning on exclusive load/stores.
Thanks,
Tejas.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Patch, Gas, AArch64][0/1] Fix diagnostics for exclusive load/stores and reclassify Armv8.7-A ST/LD64 Atomics.
2021-03-15 13:00 [Patch, Gas, AArch64][0/1] Fix diagnostics for exclusive load/stores and reclassify Armv8.7-A ST/LD64 Atomics Tejas Belagod
@ 2021-04-06 15:36 ` Nick Clifton
2021-04-09 15:04 ` Tejas Belagod
0 siblings, 1 reply; 4+ messages in thread
From: Nick Clifton @ 2021-04-06 15:36 UTC (permalink / raw)
To: binutils
Hi Tejas,
Patch series approved - please apply them all.
Cheers
Nick
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: [Patch, Gas, AArch64][0/1] Fix diagnostics for exclusive load/stores and reclassify Armv8.7-A ST/LD64 Atomics.
2021-04-06 15:36 ` Nick Clifton
@ 2021-04-09 15:04 ` Tejas Belagod
2021-04-09 15:34 ` Nick Clifton
0 siblings, 1 reply; 4+ messages in thread
From: Tejas Belagod @ 2021-04-09 15:04 UTC (permalink / raw)
To: nickc; +Cc: binutils
> -----Original Message-----
> From: Binutils <binutils-bounces@sourceware.org> On Behalf Of Nick Clifton via
> Binutils
> Sent: Tuesday, April 6, 2021 4:37 PM
> To: binutils@sourceware.org
> Subject: Re: [Patch, Gas, AArch64][0/1] Fix diagnostics for exclusive load/stores
> and reclassify Armv8.7-A ST/LD64 Atomics.
>
> Hi Tejas,
>
> Patch series approved - please apply them all.
>
Thanks Nick. OK to backport them to 2.36 - they apply cleanly and tests are happy on aarch64-none-elf?
Thanks,
Tejas
> Cheers
> Nick
^ permalink raw reply [flat|nested] 4+ messages in thread
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2021-03-15 13:00 [Patch, Gas, AArch64][0/1] Fix diagnostics for exclusive load/stores and reclassify Armv8.7-A ST/LD64 Atomics Tejas Belagod
2021-04-06 15:36 ` Nick Clifton
2021-04-09 15:04 ` Tejas Belagod
2021-04-09 15:34 ` Nick Clifton
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