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From: Richard Henderson <richard.henderson@linaro.org>
To: Kyrill Tkachov <kyrylo.tkachov@foss.arm.com>,
	"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
	"agraf@suse.de" <agraf@suse.de>,
	Marcus Shawcroft <Marcus.Shawcroft@arm.com>,
	James Greenhalgh <James.Greenhalgh@arm.com>
Subject: Re: [PATCH, AArch64, v3 4/6] aarch64: Add out-of-line functions for LSE atomics
Date: Thu, 05 Sep 2019 12:13:00 -0000	[thread overview]
Message-ID: <a6dd263a-61be-eef5-0214-e208e40bf820@linaro.org> (raw)
In-Reply-To: <38e61fc9-6418-1036-058d-2a9d961dac57@foss.arm.com>

On 9/5/19 3:00 AM, Kyrill Tkachov wrote:
>> +/* Define the symbol gating the LSE implementations.  */
>> +extern _Bool __aa64_have_atomics
>> +    __attribute__((visibility("hidden"), nocommon));
>> +
> 
> Bootstrapping this patch series on an Armv8-A system with OOL atomics enabled
> by default gave me link errors
> 
> when building libgomp about __aa64_have_atomics being undefined.
> 
> I haven't followed the series from the start so maybe I'm missing some things,
> but I don't see where this variable is supposed to "live"?

Removing the extern here is the correct fix.

Obviously the v3 patch set conversion from C to assembly wasn't properly
tested, or I made some last-minute changes before posting.  Time has erased
that memory.

> Removing the 'extern' from here allows the bootstrap to proceed but it fails at
> a later stage with bizzare errors like:
> 
> In file included from build/gencondmd.c:51:
> $SRC/gcc/config/aarch64/constraints.md: In function ‘bool
> satisfies_constraint_S(rtx)’:
> $SRC/gcc/config/aarch64/constraints.md:120:10: error: ‘C’ was not declared in
> this scope; did you mean ‘PC’?
>   120 | (define_constraint "Y"
>       |          ^
>       |          PC
> 
> which looks like a miscompilation of sorts.

I noticed a couple of typos in the assembly that used the wrong register form
(wN vs xN) on the LSE instructions.  By chance were you testing on a system
with LSE instructions enabled?


r~

  reply	other threads:[~2019-09-05 12:13 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-01 21:47 [PATCH, AArch64, v3 0/6] LSE atomics out-of-line Richard Henderson
2018-11-01 21:46 ` [PATCH, AArch64, v3 1/6] aarch64: Extend %R for integer registers Richard Henderson
2018-11-01 21:46 ` [PATCH, AArch64, v3 2/6] aarch64: Implement TImode compare-and-swap Richard Henderson
2018-11-01 21:47 ` [PATCH, AArch64, v3 3/6] aarch64: Tidy aarch64_split_compare_and_swap Richard Henderson
2018-11-01 21:47 ` [PATCH, AArch64, v3 6/6] Enable -matomic-ool by default Richard Henderson
2018-11-01 21:47 ` [PATCH, AArch64, v3 4/6] aarch64: Add out-of-line functions for LSE atomics Richard Henderson
2019-09-05 10:00   ` Kyrill Tkachov
2019-09-05 12:13     ` Richard Henderson [this message]
2019-09-05 12:53       ` Kyrill Tkachov
2018-11-01 21:47 ` [PATCH, AArch64, v3 5/6] aarch64: Implement -matomic-ool Richard Henderson
2019-09-05  9:56   ` Kyrill Tkachov
2019-09-05 12:17     ` Richard Henderson
2018-11-11 12:30 ` [PATCH, AArch64, v3 0/6] LSE atomics out-of-line Richard Henderson
2019-09-05  9:51 ` Kyrill Tkachov

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