From: Daniel Jacobowitz <drow@false.org>
To: Ramana Radhakrishnan <ramana.radhakrishnan@codito.com>,
Joel Brobecker <brobecker@adacore.com>
Cc: Wu Zhou <woodzltc@cn.ibm.com>, gdb@sourceware.org
Subject: Re: a question about rs6k's prologue analysis
Date: Wed, 11 Oct 2006 13:53:00 -0000 [thread overview]
Message-ID: <20061011135335.GB25745@nevyn.them.org> (raw)
In-Reply-To: <1160563558.5061.15.camel@localhost.localdomain>
[Please don't top-post :-)]
On Wed, Oct 11, 2006 at 04:15:58PM +0530, Ramana Radhakrishnan wrote:
> I am guessing a bit but you could use it for "milli" calls to functions
> to save callee save registers ? Was this done on the PowerPC at any
> time ?
>
> If it is in the first 3 instructions then maybe its a milli-call and you
> might have other instructions in the prologue after that.
There are such functions on some PowerPC ABIs, but I don't think GDB
supports them particularly well. This particular one is for something
different: it's loading the GOT pointer.
> On Wed, 2006-10-11 at 18:12 +0800, Wu Zhou wrote:
> > In function skip_prologue of rs6000-tdep.c, when it finds an instruction like "bl foo", and that it
> > is not within the first three instructions of the prologue, the prologue analysis will stop.
> >
> > else if ((op & 0xfc000001) == 0x48000001)
> > { /* bl foo,
> > to save fprs??? */
> >
> > fdata->frameless = 0;
> > /* Don't skip over the subroutine call if it is not within
> > the first three instructions of the prologue. */
> > if ((pc - fdata->func_start) > 8)
> > break;
> > ....
> > }
> >
> > Any specific reason for this?
I knew this sounded familiar. Here it is:
http://sourceware.org/ml/gdb-patches/2004-12/msg00234.html
http://sourceware.org/ml/gdb-patches/2005-06/msg00242.html
Joel, things have changed a lot since then - if you have a chance to
respond to my last message there, I'll take another look at it.
--
Daniel Jacobowitz
CodeSourcery
next prev parent reply other threads:[~2006-10-11 13:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-11 10:13 Wu Zhou
2006-10-11 10:47 ` Ramana Radhakrishnan
2006-10-11 13:53 ` Daniel Jacobowitz [this message]
2006-10-11 16:22 ` Joel Brobecker
2006-10-12 3:59 ` Wu Zhou
2006-10-13 4:13 ` Wu Zhou
2006-10-13 19:09 ` Michael Snyder
2006-10-13 22:03 ` Daniel Jacobowitz
2006-10-14 15:18 ` Wu Zhou
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