From: "H.J. Lu" <hjl.tools@gmail.com>
To: Alan Modra <amodra@gmail.com>
Cc: Nick Clifton <nickc@redhat.com>, Binutils <binutils@sourceware.org>
Subject: Re: PR28827 - [2.38 Regression] ld hits assertion building LLVM 9 on powerpc64le-linux-gnu
Date: Fri, 4 Feb 2022 06:36:30 -0800 [thread overview]
Message-ID: <CAMe9rOrTGB4vG=oYuNGWb87Ymh5j6QgmCR9BY-sYqWbRWbR=yQ@mail.gmail.com> (raw)
In-Reply-To: <Yf0IpSteyH3KQHOx@squeak.grove.modra.org>
On Fri, Feb 4, 2022 at 3:06 AM Alan Modra <amodra@gmail.com> wrote:
>
> Hi Nick, HJ,
> I've spent most of today debugging a build of libclang-cpp.so.9 using
> the binutils 2.38 release branch. The problem occurs after only a few
> iterations of stub sizing, so all the patches I already committed for
> potential bugs when we hit 20 iteration don't so anything as far as
> actually linking the real object files.
>
> The problem is caused by the new relro code introducing a gap at the
> end of the relro segment. On powerpc64 that means between the .got
> and .plt section. That gap changes when .eh_frame shrinks after
> consolidating CIEs and garbage collecting unused FDEs, which happens
> after the stub sizing passes are run from ldemul_after_allocation.
> Unfortunately, if the .got/.plt gap increases, plt call stubs may need
> to be larger to access addresses in the PLT from the toc pointer reg
> and thus not fit in space allocated for them.
I ran into similar issues when I was implementing DT_RELR on x86.
I added size_relative_relocs and finish_relative_relocs hooks to
resolve them.
> Please revert the relro patches on the branch. I'm now certain that
> PR28827 is directly caused by them.
I submit a patch to remove the 1-page gap only for x86:
https://sourceware.org/pipermail/binutils/2022-February/119625.html
--
H.J.
prev parent reply other threads:[~2022-02-04 14:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-04 11:06 Alan Modra
2022-02-04 14:36 ` H.J. Lu [this message]
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