From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cagney <ac131313@cygnus.com>
To: "H . J . Lu" <hjl@lucon.org>
Cc: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>, Richard Henderson <rth@redhat.com>, David B Anderson <davea@quasar.engr.sgi.com>, gdb@sourceware.cygnus.com, binutils@sourceware.cygnus.com
Subject: Re: Why does mips define elf_backend_sign_extend_vma to true?
Date: Wed, 08 Aug 2001 08:18:00 -0000
Message-id: <3B71582D.4050003@cygnus.com>
References: <20010807232102.A19636@lucon.org> <Pine.GSO.3.96.1010808100426.21622B-100000@delta.ds2.pg.gda.pl> <20010808072922.C26704@lucon.org> <3B7151C1.4030203@cygnus.com> <20010808080306.C26983@lucon.org>
X-SW-Source: 2001-08/msg00069.html

> 
> 
> Please try
> 
> 1. Find a decent compiler for Linux/mips.
> 2. Check out the Linux mips kernel from oss.sgi.com.
> 3. Compile the kernel with -g.
> 4. Compile Linux/mips gdb with 64bit BFD.
> 5. Do


You might need to find a simpler test!


> The problem is the 64bit BFD does the sign extension to the section
> addresses which have the bit 31 set. Gdb cannot find 0x8011c530 in
> those ranges. You may say oh, let's fix gdb to do
> 
> (gdb) p printk
> $1 = {int (char *)} 0xffffffff8011c530
> 
> I don't think it will be useful to me. I don't think I can set a break
> pount at 0xffffffff8011c530. The sign extension here is only the
> artifact of the 64bit BFD. My mips target is 32bit.


There is a bug but the underlying problem is the oposite of what you 
claim.  Something is breaking that simple always sign-extend rule 
(forgetting to sign extend something) and, as a consequence, the symbol 
lookup is failing.

Remember people around here spent years fighting GDB and BFD MIPS 
braindamage until someone realised it was all backwards.

	Andrew