From: fche@redhat.com (Frank Ch. Eigler)
To: Ian Lance Taylor <iant@google.com>
Cc: Fumiaki Isoya <isoyaf@gmail.com>, gcc@gcc.gnu.org
Subject: Re: The Extension to ELF
Date: Wed, 08 Aug 2012 11:23:00 -0000 [thread overview]
Message-ID: <y0mr4rhsk4r.fsf@fche.csb> (raw)
In-Reply-To: <CAKOQZ8xJUh8KXt3hG48mVUCQmdcm7TijOiY_zgOFY6p35QNN2g@mail.gmail.com> (Ian Lance Taylor's message of "Tue, 7 Aug 2012 23:31:50 -0700")
Ian Lance Taylor <iant@google.com> writes:
> [...]
> ELF is designed to permit fast program loading at runtime, and to
> permit fast linking. Changing symbol and relocation values to take
> general expressions works against that goal.
> [...]
It may interest you to know that, for an older Cygnus project (mep),
we implemented a facility called computed/complex relocations, as an
ELF extension. This is a way of encoding general symbol/arithmetic
expressions to be evaluated at link time and substituted into the
binary output. (It may be similar to the vms-alpha ETIR facility.)
This has been merged into gnu binutils some time ago, though is not
widely known, and only used by a single cgen-based gas port. See the
OBJ_COMPLEX_RELC conditionals in gas/*, the BSF_*RELC/STT_RELC logic
in bfd/*.
- FChE
next prev parent reply other threads:[~2012-08-08 11:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-08 5:39 Fumiaki Isoya
2012-08-08 6:32 ` Ian Lance Taylor
2012-08-08 7:47 ` Fumiaki Isoya
2012-08-08 11:23 ` Frank Ch. Eigler [this message]
2012-08-08 13:24 ` Ian Lance Taylor
2012-08-08 13:34 ` Frank Ch. Eigler
2012-08-08 15:42 ` Fumiaki Isoya
2012-08-08 16:23 ` Frank Ch. Eigler
2012-08-08 17:36 ` Fumiaki Isoya
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