[PATCH v2] x86: Turn PLT32 to PC32 only for PC-relative relocations

[H.J. Lu]

On Mon, Sep 23, 2024 at 1:55 AM Fangrui Song <i@maskray.me> wrote:
>
> On Sun, Sep 22, 2024 at 4:05 AM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > commit 292676c15a615b5a95bede9ee91004d3f7ee7dfd
> > Author: H.J. Lu <hjl.tools@gmail.com>
> > Date:   Thu Feb 13 13:44:17 2020 -0800
> >
> >     x86: Resolve PLT32 reloc aganst local symbol to section
> >
> > resolved PLT32 relocation against local symbol to section and
> >
> > commit 2585b7a5ce5830e60a089aa2316a329558902f0c
> > Author: H.J. Lu <hjl.tools@gmail.com>
> > Date:   Sun Jul 19 06:51:19 2020 -0700
> >
> >     x86: Change PLT32 reloc against section to PC32
> >
> > turned PLT32 relocation against section into PC32 relocation.  But these
> > transformations are valid only for PC-relative relocations.  Add fx_pcrel
> > check for PC-relative relocations when performing these transformations.
> >
> >
> > --
> > H.J.
>
> The code looks good to me.
>
> Perhaps mentioning that  `movq $foo@PLT, %rax` generates the wrong 32
> instead of PLT32 makes it easier for readers to understand the
> difference.
>
> The new file ld/testsuite/ld-x86-64/pr32196.s could be renamed to
> plt<something>.s for better discoverability.

Here is the v2 patch I am checking in.  Changes in v2:

1. Mention  `movq $foo@PLT, %rax` in the commit log.
2. Rename the linker test to plt3.s and call foo instead of loading the
first 8 bytes in foo.

Thanks.

-- 
H.J.
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