From: Jan Beulich <jbeulich@suse.com>
To: Dmitry Selyutin <ghostmansd@gmail.com>
Cc: lkcl <luke.leighton@gmail.com>,
Binutils <binutils@sourceware.org>, Alan Modra <amodra@gmail.com>
Subject: Re: Teaching expression() to treat some operations specially
Date: Tue, 12 Jul 2022 08:25:15 +0200 [thread overview]
Message-ID: <473de1ae-ab00-357c-56e1-a12e2eab779a@suse.com> (raw)
In-Reply-To: <CAMqzjeu6N-TSnYGTqgAC=a332yAOXfmJ8RmoRyWsNtOq9KbEgQ@mail.gmail.com>
On 12.07.2022 06:18, Dmitry Selyutin via Binutils wrote:
> On Tue, Jul 12, 2022 at 2:37 AM Alan Modra <amodra@gmail.com> wrote:
>>
>> You should not call expression like this without some syntactic
>> element being consumed.
>
> The expression() is not the culprit, it's the fact that operand() does
> not set all the expression fields from the symbol.
> The patch below "fixes" it, though I'm quite dubious regarding whether
> this is a fix at all.
>
> diff --git a/gas/expr.c b/gas/expr.c
> index f4ea24717d..a46e220526 100644
> --- a/gas/expr.c
> +++ b/gas/expr.c
> @@ -1350,8 +1350,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
> }
> else if (mode != expr_defer && segment == reg_section)
> {
> - expressionP->X_op = O_register;
> - expressionP->X_add_number = S_GET_VALUE (symbolP);
> + *expressionP = *symbol_get_value_expression (symbolP);
> }
May I ask which other struct fields are consumed and where? It is
my understanding that for O_register other fields simply are
invalid ...
> However, about using expression() in md_operand(), there's another question.
> One of particular cases we're interested in is extending operands with
> the vector notation.
> For example, *%r3 would mean "vector register %r3, same as %r3, but
> operating on a vector".
> This is the code we're currently using; what'd be the safe way to
> replace expression()?
Maybe you want to recognize * as a unary operator, assigning it
one of the O_md<N> values?
Jan
next prev parent reply other threads:[~2022-07-12 6:25 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-09 16:47 Dmitry Selyutin
2022-07-11 1:01 ` Alan Modra
2022-07-11 2:33 ` lkcl
2022-07-11 3:08 ` Alan Modra
2022-07-11 14:28 ` Dmitry Selyutin
2022-07-11 19:13 ` Dmitry Selyutin
2022-07-11 23:37 ` Alan Modra
2022-07-12 4:18 ` Dmitry Selyutin
2022-07-12 6:25 ` Jan Beulich [this message]
2022-07-12 6:47 ` Dmitry Selyutin
2022-07-12 6:57 ` Jan Beulich
2022-07-12 8:50 ` Dmitry Selyutin
2022-07-12 10:44 ` Jan Beulich
2022-07-12 11:17 ` Dmitry Selyutin
2022-07-12 11:39 ` Jan Beulich
2022-07-12 9:01 ` Dmitry Selyutin
2022-07-12 6:58 ` Dmitry Selyutin
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