Re: [RFA] Introduce solib_loaded observer

[Daniel Jacobowitz <drow at false dot org>]

On Sun, Jan 09, 2005 at 11:58:18PM +0100, Mark Kettenis wrote:
>    Date: Sun, 9 Jan 2005 17:37:33 -0500
>    From: Daniel Jacobowitz <drow@false.org>
> 
>    On Sun, Jan 09, 2005 at 02:05:15PM +0100, Mark Kettenis wrote:
>    >
>    > Calling the observer after loading the symbols isn't possible.  You
>    > can set "auto-solib-add" to 0, and then the symbols will never be
>    > loaded at all.  So you'll always have to force loading the symbols
>    > from within your observer anyway (but you only have to do so for the
>    > threads library).  From a code perspective the point where the
>    > notification is called is the most logical.  And that way it's less
>    > likely that we see "auto-solib-add" related bugs ;-).
> 
>    At the same time, I worry that it's going to be confusingly
>    inconsistent - for instance, I would have expected turning off
>    auto-solib-add to prevent loading symbols for libpthread!  Or at least,
>    loading of full symbols (all libthread_db on GNU/Linux really needs are
>    a couple of minsyms).
> 
> We should try to be as consistent as possible.  The current situation
> is very inconsistent too: if you turn off auto-solib-add, you won't
> get thread debugging support.  It's true that for debugging support

Note that there's no other way to deliberately turn off thread
debugging at present.

> you usually only need a few minimal symbols.  I considered rolling my
> own BFD-based lookup function, but I suspect that would result in a
> serious performance hit because I'd lose the benefit of caching.

I doubt it would be that serious.  It'd be a bit tricky, of course, so
adding extra code for it seems like a shame.  Perhaps we could read in
just the minsyms...

> Because of the auto-solib-add issue I don't think it is, but given the
> right arguments I think you can make me think differently.  What to
> the others think of this?

I wonder if we can envision any other potential consumers for this
hook?  What would they want to do?

-- 
Daniel Jacobowitz