From: Indu Bhagat <indu.bhagat@oracle.com>
To: Jan Beulich <jbeulich@suse.com>, Binutils <binutils@sourceware.org>
Cc: "H.J. Lu" <hjl.tools@gmail.com>
Subject: Re: [PATCH] x86: adjust which Dwarf2 register numbers to use
Date: Thu, 15 Feb 2024 14:22:05 -0800 [thread overview]
Message-ID: <15c6acc7-21f8-44bb-bf0d-97392f2fcd37@oracle.com> (raw)
In-Reply-To: <262f296e-673b-47f0-a764-276939161d64@suse.com>
On 2/9/24 00:11, Jan Beulich wrote:
> Consumers can't know which execution mode is in effect for a certain
> piece of code; they can only go from object file properties. Hence which
> register numbers to encode ought to depend solely on object file type.
>
> --- a/gas/config/tc-i386.c
> +++ b/gas/config/tc-i386.c
> @@ -5409,7 +5409,7 @@ ginsn_dw2_regnum (const reg_entry *ireg)
> if (ireg->reg_num == RegIP || ireg->reg_num == RegIZ)
> return GINSN_DW2_REGNUM_RSI_DUMMY;
>
> - dwarf_reg = ireg->dw2_regnum[flag_code >> 1];
> + dwarf_reg = ireg->dw2_regnum[object_64bit];
>
> if (dwarf_reg == Dw2Inval)
> {
> @@ -17461,7 +17461,7 @@ tc_x86_parse_to_dw2regnum (expressionS *
> if ((addressT) exp->X_add_number < i386_regtab_size)
> {
> exp->X_add_number = i386_regtab[exp->X_add_number]
> - .dw2_regnum[flag_code >> 1];
> + .dw2_regnum[object_64bit];
> if (exp->X_add_number != Dw2Inval)
> exp->X_op = O_constant;
> }
On one hand, I see that the suggested code changes are making things
semantically clearer, I would like to understand:
1. If there is a scenario where flag_code is CODE16_BIT / CODE32_BIT and
object_64bit equal to 1 is supported. gcc passes --32 when using -m16
or -m32.
2. Irrespective of #1, shouldn't we then also use "if (object_64bit ==
1)" instead of "if (flag_code == CODE_64BIT)" in md_begin where we set
the value of x86_dwarf2_return_column etc ?
Thanks
next prev parent reply other threads:[~2024-02-15 22:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-09 8:11 Jan Beulich
2024-02-15 22:22 ` Indu Bhagat [this message]
2024-02-16 7:26 ` Jan Beulich
2024-02-20 23:04 ` Indu Bhagat
2024-02-21 7:34 ` Jan Beulich
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