From: Roland McGrath <roland@hack.frob.com>
To: Chris Metcalf <cmetcalf@tilera.com>
Cc: <libc-alpha@sourceware.org>, <libc-ports@sourceware.org>
Subject: Re: [PATCH] tile: support very large shared objects
Date: Wed, 07 Nov 2012 18:12:00 -0000 [thread overview]
Message-ID: <20121107181235.8131B2C0CE@topped-with-meat.com> (raw)
In-Reply-To: Chris Metcalf's message of Saturday, 3 November 2012 09:28:48 -0400 <50951C10.2050704@tilera.com>
> > csu/ is not enough. You also need to use the flag for all of *_nonshared.a
> > (.oS files). That too is code that's always statically linked into
> > applications.
>
> I did think about this. My conclusion was that since *_nonshared.a is
> linked last, it will always be at the end of the generated object, so jumps
> and calls will always be able to "reach" other things linked in from
> *_nonshared.a as well as the PLT, which immediately follows the text
> section. Thus, no need for large model. In practice this does appear to
> be the case. (And this large model code is noticeably slower than regular
> mode, and we've verified that it works at the customer with the actual
> large object this way, for what that's worth.)
There are many ways to arrive at a situation where these assumptions fall
down. In general, we try to keep things fully general-purpose and not bake
in presumptions of this nature about what users do in the range of valid
inputs. But since this is for a machine-specific, rarely-used option we'll
leave it up to you to decide about those tradeoffs.
prev parent reply other threads:[~2012-11-07 18:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-03 3:42 Chris Metcalf
2012-11-03 4:47 ` Roland McGrath
2012-11-03 13:28 ` Chris Metcalf
2012-11-05 21:31 ` Chris Metcalf
2012-11-07 18:12 ` Roland McGrath [this message]
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