From: Jan Beulich <jbeulich@suse.com>
To: "Maciej W. Rozycki" <macro@embecosm.com>
Cc: binutils@sourceware.org, Fangrui Song <i@maskray.me>
Subject: Re: objdump riscv: Stop disassembling addi rd, rs, 0 with a relocation as mv rd, rs?
Date: Tue, 7 Feb 2023 16:14:47 +0100 [thread overview]
Message-ID: <53fa13a4-9828-94a7-b639-991ced5da25b@suse.com> (raw)
In-Reply-To: <alpine.DEB.2.20.2302071415340.7841@tpp.orcam.me.uk>
On 07.02.2023 15:39, Maciej W. Rozycki wrote:
> On Mon, 6 Feb 2023, Fangrui Song wrote:
>> In llvm-project, https://reviews.llvm.org/D143345 brings up the topic
>> whether we should keep addi rd, rs, 0 when it is associated with a
>> relocation. If it does, the relocation may resolve to a non-zero and
>> `mv rd, rs` may look confusing.
>
> I agree, I was quite amused when I came across it a while before, and I
> can imagine people may get confused.
I agree as well.
> However it may be quite hard to implement given how the GNU disassembler
> has been structured; most easily probably by setting the `no_aliases' flag
> temporarily for any instruction seen with a relocation attached. This
> could have undesired consequences elsewhere though and would most likely
> make Jan unhappy who wants to see aliases in disassembly rather than
> machine instruction mnemonics with the immediate forms.
>
> So instead we may need another flag for the opcode table, such as
> INSN_NORELOC, which would exclude the given entry for instructions with
> any relocation attached; I think this would be the cleanest approach,
> though maybe a little bit more involving implementation-wise.
Could we get away with simply skipping aliases in general when there's a
relocation for an insn?
Jan
next prev parent reply other threads:[~2023-02-07 15:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-07 2:40 Fangrui Song
2023-02-07 14:39 ` Maciej W. Rozycki
2023-02-07 15:14 ` Jan Beulich [this message]
2023-02-07 15:44 ` Andreas Schwab
2023-02-07 16:04 ` Maciej W. Rozycki
2023-02-09 2:21 ` Nelson Chu
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