From: Aurelien Jarno <aurelien@aurel32.net>
To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH for-next 6/8] tcg-i386: Use new return-argument ld/st helpers
Date: Fri, 16 Aug 2013 10:35:15 +0200 [thread overview]
Message-ID: <20130816083515.GA4795@ohm.aurel32.net> (raw)
In-Reply-To: <520D3D98.80306@twiddle.net>
On Thu, Aug 15, 2013 at 01:44:08PM -0700, Richard Henderson wrote:
> On 08/15/2013 08:54 AM, Aurelien Jarno wrote:
> >> > # define GETRA() ((uintptr_t)__builtin_return_address(0))
> >> > -# define GETPC_LDST() ((uintptr_t)(GETRA() + 7 + \
> >> > - *(int32_t *)((void *)GETRA() + 3) - 1))
> >> > +/* The return address argument for ldst is passed directly. */
> >> > +# define GETPC_LDST() (abort(), 0)
> > Why an abort here, while in the arm version, you adds support for
> > not defining GETPC_LDST?
> >
>
> GETPC_LDST is for the original helpers, when called from TCG.
>
> In the arm case, TCG still uses the original helpers, so GETPC_LDST is used.
>
> In the i386, TCG never uses the original helpers, so GETPC_LDST should never be
> used. We could do like arm and completely drop the check, I suppose.
Ok, I haven't looked in details at the arm patches (i am currently
trying them), and I haven't really seen the difference. Then just ignore
this comment.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@aurel32.net http://www.aurel32.net
next prev parent reply other threads:[~2013-08-16 8:39 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-05 18:07 [Qemu-devel] [PATCH for-next 0/8] Improve tcg ldst optimization Richard Henderson
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 1/8] tcg-i386: Add and use tcg_out64 Richard Henderson
2013-08-15 15:54 ` Aurelien Jarno
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 2/8] tcg-i386: Try pc-relative lea for constant formation Richard Henderson
2013-08-15 15:54 ` Aurelien Jarno
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 3/8] tcg-i386: Tidy qemu_ld/st slow path Richard Henderson
2013-08-15 15:54 ` Aurelien Jarno
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 4/8] tcg: Add mmu helpers that take a return address argument Richard Henderson
2013-08-15 15:54 ` Aurelien Jarno
2013-08-15 20:45 ` Richard Henderson
2013-08-16 8:35 ` Aurelien Jarno
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 5/8] tcg: Tidy softmmu_template.h Richard Henderson
2013-08-15 15:54 ` Aurelien Jarno
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 6/8] tcg-i386: Use new return-argument ld/st helpers Richard Henderson
2013-08-15 15:54 ` Aurelien Jarno
2013-08-15 20:44 ` Richard Henderson
2013-08-16 8:35 ` Aurelien Jarno [this message]
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 7/8] tcg-arm: Use ldrd/strd for appropriate qemu_ld/st64 Richard Henderson
2013-08-05 18:07 ` [Qemu-devel] [PATCH for-next 8/8] tcg-arm: Rearrange slow-path qemu_ld/st Richard Henderson
2013-08-16 8:36 ` Aurelien Jarno
2013-08-16 8:55 ` Andreas Färber
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