[LLVMdev] Some thought on handling ELF shared libraries in lld

[Rafael Espíndola]

On 21 July 2015 at 12:03, Dave Bozier <seifsta at gmail.com> wrote:
>> It is technically possible. But we have to find the total symbols
>> early (symbol resolution) and so we would need to do an early scan of
>> another table just to find that number.
>
> That shouldn't be too expensive. I would expect roughly as many
> dynamic relocations as there are symbols as they will mostly just be
> patching PLT/GOT entries for them.

The dynamic relocation will cover every symbol. For example, a .so with just

void f(void) {}

in it has no relocations at all.

The hash table will cover them all. But it doesn't seem possible to easily find
the size of the gnu hash table.

> You could also make it easier by creating a new tag defining the size
> of the symbol table. That would at least allow shared libraries
> produced by lld to be able to easily parse the dynamic symbol table.
>
> Is statically linking against shared libraries that have been stripped
> of their section header tables something that is likely to be
> requested?

No, every other linker that I know of uses sections.

Cheers,
Rafael