From: Alan Modra <amodra@gmail.com>
To: Kaylee Blake <klkblake@gmail.com>
Cc: binutils@sourceware.org
Subject: Re: RFC: [PATCH] ELF: Don't require section header on ELF objects
Date: Tue, 10 Mar 2020 00:14:27 +1030 [thread overview]
Message-ID: <20200309134427.GO5384@bubble.grove.modra.org> (raw)
In-Reply-To: <79bc289f-9202-9aff-61c3-92c7190d2f7d@gmail.com>
On Mon, Mar 09, 2020 at 11:24:44PM +1030, Kaylee Blake wrote:
> On 9/3/20 6:43 pm, Florian Weimer wrote:
> > In my opinion, it should NOT be possible to link against objects
> > without section headers. Lack of section headers clearly marks the
> > object as a run-time only object. This is useful if you want to
> > prevent developers to create DT_NEEDED dependencies on internal
> > libraries, for example.
I agree.
> For shared objects without debug symbols, the section header table is
> ~2kB on average of redundant data. I'm also not a fan of the
> inconsistency of having shared libraries that the dynamic linker is
> perfectly happy to load, but ld can't link against, especially since
> this seems like an oversight rather than an intended design decision.
The ELF spec designed things that way. See figure 4.1 which I'll try
to represent in text.
Figure 4-1: Object File Format
|----------------------| |----------------------|
| ELF Header | | ELF Header |
|----------------------| |----------------------|
| Program header table | | Program header table |
| optional | | required |
|----------------------| |----------------------|
| Section 1 | | Segment 1 |
|----------------------| |----------------------|
| ... | | Segment 2 |
|----------------------| |----------------------|
| Section n | | Segment 3 |
|----------------------| |----------------------|
| ... | | ... |
|----------------------| |----------------------|
| Section header table | | Section header table |
| required | | optional |
|----------------------| |----------------------|
Linking View Execution View
--
Alan Modra
Australia Development Lab, IBM
next prev parent reply other threads:[~2020-03-09 13:44 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-08 17:59 H.J. Lu
2020-03-08 18:06 ` H.J. Lu
2020-03-08 23:35 ` Alan Modra
2020-03-08 23:46 ` H.J. Lu
2020-03-09 0:02 ` H.J. Lu
2020-03-09 0:02 ` Kaylee Blake
2020-03-09 0:05 ` Alan Modra
2020-03-09 1:36 ` H.J. Lu
2020-03-09 1:59 ` Kaylee Blake
2020-03-09 2:23 ` Alan Modra
2020-03-09 2:35 ` H.J. Lu
2020-03-09 4:14 ` H.J. Lu
2020-03-09 4:59 ` Kaylee Blake
2020-03-09 11:56 ` Alan Modra
2020-03-08 23:24 ` Kaylee Blake
2020-03-08 23:29 ` H.J. Lu
2020-03-08 23:38 ` Alan Modra
2020-03-08 23:45 ` H.J. Lu
2020-03-12 2:14 ` Fangrui Song
2020-03-09 8:13 ` Florian Weimer
2020-03-09 12:54 ` Kaylee Blake
2020-03-09 13:06 ` Florian Weimer
2020-03-09 13:14 ` Kaylee Blake
2020-03-09 13:16 ` Florian Weimer
2020-03-09 13:28 ` Kaylee Blake
2020-03-09 13:29 ` Florian Weimer
2020-03-09 13:45 ` Kaylee Blake
2020-03-09 13:54 ` H.J. Lu
2020-03-09 14:02 ` Kaylee Blake
2020-03-09 14:52 ` Florian Weimer
2020-03-09 15:07 ` Kaylee Blake
2020-03-09 15:29 ` Florian Weimer
2020-03-09 13:44 ` Alan Modra [this message]
2020-03-09 13:54 ` Kaylee Blake
2020-03-09 22:34 ` Alan Modra
2020-03-10 0:14 ` H.J. Lu
2020-03-09 14:34 ` Michael Matz
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