From: Jan Beulich <jbeulich@suse.com>
To: "Maciej W. Rozycki" <macro@orcam.me.uk>
Cc: Chenghua Xu <paul.hua.gm@gmail.com>, Binutils <binutils@sourceware.org>
Subject: Re: non-conformant ELF symbol table on MIPS?
Date: Fri, 28 Jul 2023 08:18:48 +0200 [thread overview]
Message-ID: <5a410132-b62f-b932-cb00-ee6ad0a3a99b@suse.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2307271717100.10240@angie.orcam.me.uk>
On 27.07.2023 21:28, Maciej W. Rozycki wrote:
> On Thu, 27 Jul 2023, Jan Beulich wrote:
>
>> extending the gas elf/common3.s testcase (in the context of trying to fix
>> PR gas/30688) to
>>
>> .comm foobar,30,4
>> .comm buf1, 5-1, 8
>> .comm buf2, 4, 9-1
>> .lcomm lbuf, 9-1
>>
>> I notice a violation of the ELF spec on most (all?) MIPS targets I would
>> routinely test for common code changes: "lbuf" is emitted last in the
>> symbol table. The spec is quite clear: "In each symbol table, all
>> symbols with STB_LOCAL binding precede the weak and global symbols." I
>> guess I want/need to xfail that test for mips*-*-* for the time being,
>> but it would be nice if you could shed some light on this behavior.
>
> Which specific MIPS target is it?
>
> There are two kinds of MIPS targets, ones that use the older IRIX symbol
> sorting rules and ones that use the newer "traditional" symbol sorting
> rules. The IRIX symbol sorting rules mandate that section symbols precede
> all other symbols, see e.g. bfd/elf32-mips.c:mips_elf_sym_is_global.
Along the lines of my reply to Ian: This still doesn't explain the
behavior I observe. What you say is required could still be met without
violating ELF rules.
Jan
> Mind that SGI was an early adopter of the ELF standard and things weren't
> as settled as they are nowadays, hence e.g. the odd solution for composed
> relocations with the n64 psABI (later n32 uses standard ELF gABI ones) and
> other peculiarities here and there.
>
> Determining whether a MIPS target uses the IRIX emulation is complex, see
> e.g. how binutils/testsuite/binutils-all/mips/mips.exp sets `irixemul'.
> If you provide me with test case details (input and output), then I may be
> able to give you further advice, but otherwise you may want to mark the
> test case with `notarget' or suchlike rather than `xfail', because that's
> not a bug with the backend that the symbol ordering varies.
>
> Maciej
next prev parent reply other threads:[~2023-07-28 6:18 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-27 14:27 Jan Beulich
2023-07-27 19:04 ` Ian Lance Taylor
2023-07-27 19:39 ` Maciej W. Rozycki
2023-07-28 6:16 ` Jan Beulich
2023-07-28 17:11 ` Ian Lance Taylor
2023-07-28 23:58 ` Alan Modra
2023-07-27 19:28 ` Maciej W. Rozycki
2023-07-28 6:13 ` Jan Beulich
2023-07-28 7:18 ` Jan Beulich
2023-07-28 6:18 ` Jan Beulich [this message]
2023-07-28 6:56 ` Maciej W. Rozycki
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