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From: Joel Brobecker <brobecker@adacore.com>
To: Pedro Alves <pedro_alves@portugalmail.pt>
Cc: gdb-patches@sourceware.org
Subject: Re: [i386/stabs] Arguments of main on gcc >= 4.1
Date: Mon, 03 Dec 2007 18:25:00 -0000	[thread overview]
Message-ID: <20071203182540.GB14306@adacore.com> (raw)
In-Reply-To: <47503C57.6010308@portugalmail.pt>

> Since gcc 4.1 and later started putting code in the prologue
> to realign the stack pointer, the offset on the
> parameter stabs changed from being relative to the frame pointer
> to being relative to the argument's address.

This is somewhat fuzzy because the stabs format has never been really
well defined like DWARF is, but IMO this is a GCC bug.

> E.g.:
>     int main (int argc, char **argv, char **envp);
> 
> notice the 0, 4, 8:
> 
>           .zero   16
>           .text
>           .stabs  "main:F(0,1)",36,0,10,main
>           .stabs  "argc:p(0,1)",160,0,9,0
>           .stabs  "argv:p(0,16)=*(3,54)",160,0,9,4
>           .stabs  "envp:p(0,16)",160,0,9,8
> .globl main
>           .type   main, @function

Looking at your example above, what would work is if GCC was using
N_LSYM (128) symbols instead of N_PSYM symbols (160).

I would definitely be interested in what others think on this.

-- 
Joel


  reply	other threads:[~2007-12-03 18:25 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-30 16:40 Pedro Alves
2007-12-03 18:25 ` Joel Brobecker [this message]
2007-12-17  0:47   ` Daniel Jacobowitz
2007-12-17  6:42     ` Joel Brobecker
2007-12-17 13:33       ` Daniel Jacobowitz
2007-12-17 15:06         ` Joel Brobecker
2007-12-28  1:20           ` Pedro Alves
2007-12-28 14:31             ` Joel Brobecker
2007-12-28 22:36               ` Pedro Alves
2007-12-29  3:42                 ` Joel Brobecker
2007-12-30  4:38             ` Daniel Jacobowitz

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