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From: Pedro Alves <pedro@codesourcery.com>
To: gdb-patches@sourceware.org
Subject: Re: [patch][rfc] Allow GDB to search for the right libthread_db.so.1
Date: Mon, 11 May 2009 21:09:00 -0000
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Cc: Paul Pluzhnikov <ppluzhnikov@google.com>,  Joel Brobecker <brobecker@adacore.com>,  Hui Zhu <teawater@gmail.com>,  tromey@redhat.com,  Thiago Jung Bauermann <bauerman@br.ibm.com>,  Eli Zaretskii <eliz@gnu.org>,  Daniel Jacobowitz <drow@false.org>
References: <8ac60eac0904201019g7ba8056bx5e84e6bfdf5935d8@mail.gmail.com> <200905111412.59493.pedro@codesourcery.com> <8ac60eac0905111108g26096302lb902cd414b5a6790@mail.gmail.com>
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On Monday 11 May 2009 19:08:46, Paul Pluzhnikov wrote:
> On Mon, May 11, 2009 at 6:12 AM, Pedro Alves <pedro@codesourcery.com> wrote:
> 
> >> handle = dlopen (library, RTLD_NOW);
> >
> > I wonder if making this RTLD_LAZY until you found the correct one
> > wouldn't make sense?
> 
> I don't believe so.
> 
> AFAICT, the reason for RTLD_NOW is to make sure that this
> libthread_db is really compatible with this GDB (doesn't require
> any symbols GDB doesn't provide); and also to prevent GDB from
> dying half way through with "unable to resolve symbol ...".

Yeah.

> Both of these still apply to whatever the "final" libthread_db is
> going to be.
> 
> Why would we want to dlopen(... RTLD_LAZY) and try to initialize
> libthread_db if we are going to reject it as unusable in the end?

To avoid immediate binding of random libc's, but yeah, brain f*rt.

-- 
Pedro Alves