From: Aurelien Jarno <aurelien@aurel32.net>
To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 04/10] tcg/mips: don't use global pointer
Date: Fri, 21 Sep 2012 23:13:05 +0200 [thread overview]
Message-ID: <20120921211305.GA15029@ohm.aurel32.net> (raw)
In-Reply-To: <505CAF7F.9050505@twiddle.net>
On Fri, Sep 21, 2012 at 11:18:39AM -0700, Richard Henderson wrote:
> On 09/21/2012 09:43 AM, Aurelien Jarno wrote:
> > Don't use the global pointer in TCG, in case helpers try access global
> > variables.
>
> Err.. isn't the GP computed at the entry point of functions that need to use it?
I read that GP should be preserved when checking the MIPS ABI for other
things. But you are right, GCC emit code to recompute GP at the entry point
of the function when used later. I guess I checked the wrong ABI.
> That said, under n32 and n64 abis it is call-saved; under o32 it's call-clobbered.
> So by itself this is still a fix for new-abis, since we don't save it in the
> prologue. OTOH, this does suggest an alternate solution... ;-)
>
Supporting n32 or n64 implies a lot more things than that. So I guess
I'll just drop that patch for now.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@aurel32.net http://www.aurel32.net
next prev parent reply other threads:[~2012-09-21 21:13 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-21 16:43 [Qemu-devel] [PATCH 00/10] tcg/mips: cleanup and improvements Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 01/10] tcg-mips: fix wrong usage of 'Z' constraint Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 02/10] tcg/mips: kill warnings in user mode Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 03/10] tcg/mips: use TCGArg or TCGReg instead of int Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 04/10] tcg/mips: don't use global pointer Aurelien Jarno
2012-09-21 18:18 ` Richard Henderson
2012-09-21 21:13 ` Aurelien Jarno [this message]
2012-09-21 16:43 ` [Qemu-devel] [PATCH 05/10] tcg/mips: use stack for TCG temps Aurelien Jarno
2012-09-22 14:37 ` Blue Swirl
2012-09-22 17:25 ` Aurelien Jarno
2012-09-22 18:09 ` Blue Swirl
2012-09-22 18:17 ` Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 06/10] tcg/mips: optimize brcond arg, 0 Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 07/10] tcg/mips: optimize bswap{16, 16s, 32} on MIPS32R2 Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 08/10] tcg/mips: implement rotl/rotr ops " Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 09/10] tcg/mips: implement deposit op " Aurelien Jarno
2012-09-21 16:43 ` [Qemu-devel] [PATCH 10/10] tcg/mips: implement movcond " Aurelien Jarno
2012-09-21 19:33 ` [Qemu-devel] [PATCH 00/10] tcg/mips: cleanup and improvements Richard Henderson
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