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Re: Support archives with 64-bit symbol table
- From: Petr Machata <pmachata at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Fri, 03 Aug 2012 01:50:29 +0200
- Subject: Re: Support archives with 64-bit symbol table
Mark Wielaard <email@example.com> writes:
> On Thu, Aug 02, 2012 at 01:43:10AM +0200, Petr Machata wrote:
>> these two patches implement support for 64-bit symbol table in .a
>> archives. As of recently, binutils' ar produces such archives on s390x
>> (regardless of actual archive size). This appears to be the same as
>> "/", except all fields are 64-bit.
> Just a quick partial review, with some pedantic comments. Have to read
> up on ar archives. But it looks correct to me. Are the magic entries
> ("/SYM64/") described somewhere in a specification document or is this
> GNU specific?
I went with the assumption that it's just like "/", except 64-bit where
"/" is 32-bit. I found something now, page 97:
This is Irix documentation, 64-bit Irix is where this format comes from.
>> - Copyright (C) 1998, 1999, 2000, 2002, 2005 Red Hat, Inc.
>> + Copyright (C) 1998-2012 Red Hat, Inc.
> This should be 1998-2000, 2002, 2005, 2012. Only the first is a full
> range. Similarly in some other places. (Yes, I did ask a lawyer.)
I'll correct this. I recalled something with coalescing individual
years into ranges, but wasn't actually sure what the rule was.
>> - /* Now test whether this is the index. It is denoted by the
>> - name being "/ ".
>> + bool index64_p;
>> + /* Now test whether this is the index. If the name is "/", this
>> + is 32-bit index, if it's "/SYM64/", it's 64-bit index.
>> XXX This is not entirely true. There are some more forms.
>> Which of them shall we handle? */
> Is this still true? Which other forms are there?
I don't know. In Linkers & Loaders, Levine mentions several different
formats for "/" and one for "__.SYMDEF". The latter was reportedly used
in original BSD and in a.out archives. I'm not sure it's relevant
> It would be more consistent to cal this run-test-archive64.sh.
Will fix. (Not that there is much consistency otherwise ;) )
>> +testfiles archive64.a
> Please document here how archive64.a was created.
Humm, I took a bunch of elfutils objects, but now that I think of it, we
would have to ship the exact same source that led to their creation.
Maybe instead I'll invent a couple trivial one-liners that can easily be
pasted to run-test-archive64.sh. Would that work?