From: fche@redhat.com (Frank Ch. Eigler)
To: Fumiaki Isoya <isoyaf@gmail.com>
Cc: Ian Lance Taylor <iant@google.com>, gcc@gcc.gnu.org
Subject: Re: The Extension to ELF
Date: Wed, 08 Aug 2012 16:23:00 -0000 [thread overview]
Message-ID: <y0mtxwdqroo.fsf@fche.csb> (raw)
In-Reply-To: <502288B8.2090802@gmail.com> (Fumiaki Isoya's message of "Thu, 09 Aug 2012 00:41:44 +0900")
Fumiaki Isoya <isoyaf@gmail.com> writes:
>> 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. [...]
>
> Did you write some compiler language to evaluate that feature?
No. Software for this particular was mainly coded in assembly, and
the assembly language / instruction set were itself very
configurable(!), so relocations had to be general. If this capability
is useful for a higher-level language, a binding would have to be
created, and the arch gas/binutils would have to start generating the
info.
> How is the idea of adopting it as the standard format of GNU Hurd?
I have no opinion on this. Note though that these complex relocations
are encoded within a standard ELF file (merely using separate
relocation-type and symbol-type codes). There is no need for an
OS/kernel to support it, since all the action takes place within the
assembler and linker.
- FChE
next prev parent reply other threads:[~2012-08-08 16:23 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
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 [this message]
2012-08-08 17:36 ` Fumiaki Isoya
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