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From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 2 Jun 2020 18:29:16 -0700
Message-ID: <CAMe9rOqtub-8Cu=bQ=EThXP_-SM3X=Fo6S0qHcZcSykR-tftmA@mail.gmail.com>
Subject: Re: [PATCH] ELF: Don't check relocations in non-loaded,
 non-alloced sections
To: Fangrui Song <i@maskray.me>
Cc: Binutils <binutils@sourceware.org>
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On Tue, Jun 2, 2020 at 5:06 PM Fangrui Song <i@maskray.me> wrote:
>
> I haven't really read the patch, but just wanted to express a point.
> It is sometimes useful to check relocations even for a non-SHF_ALLOC
> section. For example, a PC relative relocation type does not make
> sense from a non-SHF_ALLOC section referencing a SHF_ALLOC section.
>
> Conceptually, even if a non-SHF_ALLOC is loaded as part of the memory
> image, the distance between it and a SHF_ALLOC section may not be a
> constant, so the linker cannot reasonably resolve the relocation.
>

Since non-SHF_ALLOC sections have no impact on run-time behavior,
ld.so ignores dynamic relocations on non-SHF_ALLOC section.   In
checking phase, relocations on non-SHF_ALLOC section shouldn't
alter other relocatitons against the same symbol.  When resolving
such relocations, linker should ignore any relocation errors for such
relocations.


-- 
H.J.