Re: Support archives with 64-bit symbol table

[Petr Machata <pmachata at redhat dot com>]

Mark Wielaard <mjw@redhat.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:

  http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf

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
anymore.

> 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?

Thank you,
PM