From: "H. J. Lu" <hjl@lucon.org>
To: Paul Koning <pkoning@equallogic.com>
Cc: drow@false.org, gdb@sources.redhat.com
Subject: Re: find_pc_partial_function may produce the wrong answer
Date: Wed, 20 Jul 2005 16:17:00 -0000 [thread overview]
Message-ID: <20050720161546.GA27852@lucon.org> (raw)
In-Reply-To: <17118.28560.210105.359439@gargle.gargle.HOWL>
On Wed, Jul 20, 2005 at 11:36:48AM -0400, Paul Koning wrote:
> >>>>> "Daniel" == Daniel Jacobowitz <drow@false.org> writes:
>
> Daniel> On Wed, Jul 20, 2005 at 10:28:14AM -0400, Paul Koning wrote:
> >> I was tracking down a problem in my (modified) gdb, which showed
> >> up when doing callstack tracing by reading the prologue.
> >> (mips-tdep can do that, and in my version it does it most of the
> >> time.)
> >>
> >> The problem is that find_pc_partial_function is used to find the
> >> start of the function, and it was producing the wrong answer.
> >> Specifically, it produces the wrong answer when the function is in
> >> a shared library.
> >>
> >> The cause of the problem is that find_pc_partial_function looks up
> >> the symbol in the msymtab, and that contains only external
> >> symbols, not static symbols. The comments in the source code
> >> explicitly claim that it DOES contain static symbols, but "maint
> >> print msymtab" clearly shows that it doesn't. At least not for
> >> MIPS shared libraries...
>
> Daniel> Is the shared library stripped? I am absolutely positive
> Daniel> that the minimal symbol table will include the static symtab
> Daniel> - as long as there is one.
>
> Daniel> If for some reason in your modified GDB this is not the case,
> Daniel> figure out why not.
>
> It isn't related to the modified gdb; the stock gdb from CVS sources
> does the same.
>
> It looks instead like there is something bizarre going on in the
> compile. I looked in the build directory and found that the offending
> file (malloc.o) has no static syms in its symbol table according to
> readelf. But when I repeat the compile by hand I get a rather
> different looking symbol table that does have them. Need to track
> this down.
Are you using gcc 4.0/4.1 by any chance?
H.J.
next prev parent reply other threads:[~2005-07-20 16:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-20 14:28 Paul Koning
2005-07-20 14:33 ` Daniel Jacobowitz
2005-07-20 15:38 ` Paul Koning
2005-07-20 16:17 ` H. J. Lu [this message]
2005-07-20 16:24 ` Paul Koning
2005-07-20 17:09 ` Paul Koning
2005-07-20 17:13 ` Daniel Jacobowitz
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