Re: [PATCH 6/9] objtool: Add elf_create_undef_symbol()
From: Peter Zijlstra
Date: Wed Mar 17 2021 - 10:14:42 EST
On Wed, Mar 17, 2021 at 02:52:23PM +0100, Miroslav Benes wrote:
> > + if (!elf_symbol_add(elf, sym, SHN_XINDEX)) {
> > + WARN("elf_symbol_add");
> > + return NULL;
> > + }
>
> SHN_XINDEX means that the extended section index is used. Above you seem
> to use it in the opposite sense too (assigning to shndx when shndx_data is
> NULL). While it makes the code easier to handle, it is a bit confusing
> (and maybe I am just confused now). Could you add a comment about that,
> please? elf_symbol_add() seems like a good place.
Yes, that was a horrible thing to do :/ And you understood it right.
Looking at it again, I'm not sure it is actually correct tho; shouldn't
elf_create_undef_symbol() also look at gelf_getsymshndx() of symtab ?
What toolchain generates these extended sections and how? That is, how
do I test this crud..