Re: Sort output dynamic relocations.

[John David Anglin <dave.anglin@bell.net>]

On 7/10/2011 9:27 PM, Carlos O'Donell wrote:
> On Sat, Jul 9, 2011 at 11:08 AM, John David Anglin<dave.anglin@bell.net>  wrote:
>> As far as I can tell, most targets don't sort dynamic relocations.  The
>> exceptions that I see are mips and score.  Doing this will increase link time, so I
>> tend to think it should be avoided if possible.  Isn't the dynamic loader a special case?
> Ulrich Drepper says that relative relocations must *always* be first,
> it doesn't require a complete sort.
>
I'm not knowledgeable about x86 but I don't believe it has a relocation 
equivalent to the
PLABEL32 reloc.  Everything in .rel.dyn may be relative.  However, 
R_386_RELATIVE
seems to occur before R_386_GLOB_DATA.  I'm not sure how this is done.

If we need to sort, combreloc may need to be disabled because it might 
do an incompatible
sort.

> The dynamic loader is a special case, but there are some requirements.
>
>> Have you tried the ld "-z combreloc" option to see if that works?  It
>> combines reloc sections and sorts them.
> I haven't tried that yet, are you saying we should change binutils to
> *default* to "-z combreloc?"
No.  I was just thinking of trying to link the dynamic loader with this 
option.  Didn't notice
any other targets making it the default.

Dave

-- 
John David Anglin    dave.anglin@bell.net