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From: Andrew Cagney <ac131313@ges.redhat.com>
To: "Theodore A. Roth" <troth@verinet.com>
Cc: gdb-patches@sources.redhat.com
Subject: Re: [RFC] fix for avr_skip_prologue()
Date: Sun, 04 Aug 2002 17:04:00 -0000	[thread overview]
Message-ID: <3D4DC113.1000700@ges.redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0208041344450.31064-100000@oscar.mynet>

> On Sun, 4 Aug 2002, Andrew Cagney wrote:
> 
> 
>>I don't think your change is any worse than many other *_skip_prologue() 
>>tweaks.  A typical skip_prologue() function is an accumulation of 
>>heuristics and a lot of comments.
>>
> 
> 
> <snip>
> 
>>> -      if (sal.line != 0 && sal.end < func_end)
>>> +      /* troth/2002-70-19: For some very simple functions, gcc doesn't
>>> +         generate a prologue and the sal.end ends up being the insn (2 bytes)
>>> +         before func_end (the address of the next func). By adjusting
>>> +         func_end, we can catch these functions and return the correct pc. */
> 
>>
>>I'd just also mention that the instruction in question is ``return'' and 
>>is two bytes long.
> 
> 
> Let's see if I understand what you are saying here. It looks like sal.end 
> becomes the ``return'' instruction which is 1 insn (2 bytes) before 
> func_end. If so, it might make more sense for the patch to be 

Yes.  that's what I think is happening based on your comments.

> +      if (sal.line != 0 && (sal.end+2) < func_end)
> 
> Thus if sal.end is the ``return'' insn for the simple function, we just
> return the current pc instead of sal.end.
> 
> If that makes any sense to you, I'll fix the comment and commit it.

Ok.

Andrew





      reply	other threads:[~2002-08-05  0:04 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-07-19 11:52 Theodore Roth
2002-07-19 12:04 ` Andrew Cagney
2002-08-04 12:43 ` Andrew Cagney
2002-08-04 13:54   ` Theodore A. Roth
2002-08-04 17:04     ` Andrew Cagney [this message]

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