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From: Andrew Cagney <ac131313@redhat.com>
To: Mark Kettenis <kettenis@chello.nl>
Cc: mludvig@suse.cz, gdb@sources.redhat.com,
	Alexandre Oliva <aoliva@redhat.com>
Subject: Re: dwarf-frame.c question
Date: Thu, 29 May 2003 23:13:00 -0000	[thread overview]
Message-ID: <3ED693F5.9040108@redhat.com> (raw)
In-Reply-To: <200305292222.h4TMMmGm000694@elgar.kettenis.dyndns.org>

Discussed this with AlexO (of gcc).  Let us ruin your day.

This problem can occure even without recursion.  Consider the C snippet:

foo ()
{
	if (i)
	  abort (with, lots, of parameters)
	do; normal; stuff;
}

it can be turned into:

	branch !i, 1:
	push with
	push lots
	push of
	push parameters
	call abort
1:
	do
	normal
	stuff

The return address can end up pointing at the ``do'' / 1: line and 
that's CFI info is definitly not correct for unwinding from abort().

One idea (the origins of which are unknown) is for the compiler to 
generate CFI info containing no addresses and have GDB look for that 
dependant on the PC address being obtained using return or resume 
(sigtramp, sentinel).

However, first, does anyone know if the DWARF 2 spec has something to 
say abou this?

Andrew

  parent reply	other threads:[~2003-05-29 23:13 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-05-27 15:19 Michal Ludvig
2003-05-29 15:44 ` Mark Kettenis
2003-05-29 19:54   ` Andrew Cagney
2003-05-29 22:22     ` Mark Kettenis
2003-05-29 22:43       ` Michal Ludvig
2003-05-29 23:13       ` Andrew Cagney [this message]
2003-05-30  1:34         ` Daniel Jacobowitz
2003-05-30 20:21         ` Jim Blandy
2003-05-30 20:32           ` Andrew Cagney
2003-06-03  0:04             ` Jim Blandy
2003-06-03  5:47               ` Richard Henderson
2003-06-03  6:32                 ` Jim Blandy
2003-06-03 15:58                   ` Richard Henderson
2003-06-03 17:38                     ` Richard Henderson
2003-06-03 20:12                   ` Alexandre Oliva
2003-05-30 20:44           ` Alexandre Oliva
2003-05-30 20:21         ` Jim Blandy
2003-06-01  5:59 Richard Henderson
2003-06-01 10:00 ` Mark Kettenis
2003-06-02 20:34   ` Richard Henderson

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