From: Fangrui Song <maskray@google.com>
To: Xi Ruoyao <xry111@xry111.site>
Cc: WANG Xuerui <i.swmail@xen0n.name>,
liuzhensong <liuzhensong@loongson.cn>,
binutils@sourceware.org, mengqinggang@loongson.cn
Subject: Re: [PATCH v2] LoongArch: Set e_flags to 0x40 of ELF while using new relocations.
Date: Tue, 27 Sep 2022 09:49:33 -0700 [thread overview]
Message-ID: <20220927164933.hqlzldtts3xsyf4m@google.com> (raw)
In-Reply-To: <68121ec1509922e881246ebbfda15e1eadb9958a.camel@xry111.site>
On 2022-09-25, Xi Ruoyao wrote:
>On Sun, 2022-09-25 at 16:28 +0800, WANG Xuerui wrote:
>> > +
>> > + if (elf_elfheader (output_bfd)->e_ident[EI_CLASS] == ELFCLASS32)
>> > interpreter = "/lib32/ld.so.1";
>> > - else if (EF_LOONGARCH_IS_LP64 (flags))
>> > + else if (elf_elfheader (output_bfd)->e_ident[EI_CLASS] == ELFCLASS64)
>> > interpreter = "/lib64/ld.so.1";
>> > else
>> > interpreter = "/lib/ld.so.1";
>> > +
>> Wait what, are we still carrying the old-world defaults for the
>> interpreter path here? I know it's harmless because in fact it gets
>> overridden by gcc and glibc, but I'd suggest fixing it in a separate
>> patch later for consistency.
>
>It seems not easy to make a "correct" default... /lib64/ld-linux-
>loongarch-lp64d.so.1 will be incorrect for a musl-based target. Maybe
>we can assume Glibc is used because we are the *GNU* linker anyway...
>
>/* snip */
For all other architectures, the default dynamic linker is just not
useful. (ld.lld encodes no string at all.) Ideally this should be empty,
but if an empty interpreter string uses a behavior similar to --no-dynamic-linker,
use an arbitrary dummy string.
>> I'd bikeshed a little and suggest "EF_LOONGARCH_OBJABI_foo" because
>> it's actually "ELF object file ABI v1" and not "ELF ABI object v1".
>
>In the doc we say "the ABI version of an ELF object", IMO it's a little
>misleading (can trick people to believe it could be used to distinguish
>old and new world). From Wikipedia:
>
> In computer software, an application binary interface (ABI) is an
> interface between two binary program modules.
>
>I'm not sure if the (non-dynamic) relocation types belongs to the concept
>of ABI: the linker treats relocatable object files as an input (like how
>"vim" treats a text file), instead of a program module. But I can't come
>up with a better terminology for now...
>
>--
>Xi Ruoyao <xry111@xry111.site>
>School of Aerospace Science and Technology, Xidian University
next prev parent reply other threads:[~2022-09-27 16:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 1:17 liuzhensong
2022-09-25 8:28 ` WANG Xuerui
2022-09-25 9:22 ` Xi Ruoyao
2022-09-27 16:49 ` Fangrui Song [this message]
2022-09-27 2:11 ` liuzhensong
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