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Subject: Re: [PATCH] Mips: Fix the ASAN shadow offset hook for the n32 ABI
From: Xi Ruoyao <xry111@xry111.site>
To: "Maciej W. Rozycki" <macro@orcam.me.uk>, Dimitrije Milosevic
 <Dimitrije.Milosevic@Syrmia.com>
Cc: Djordje Todorovic <Djordje.Todorovic@syrmia.com>, 
 "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Date: Wed, 03 Aug 2022 09:17:16 +0800
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On Sat, 2022-07-30 at 14:22 +0100, Maciej W. Rozycki wrote:
> On Mon, 6 Jun 2022, Dimitrije Milosevic wrote:
>=20
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * config/mips/mips.cc (mips_=
asan_shadow_offset): Reformat
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 to handle the N32 ABI.
>=20
> =C2=A0That's not what the change does.
>=20
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 * config/mips/mips.h (SUBTAR=
GET_SHADOW_OFFSET): Remove
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 the macro, as it is not need=
ed anymore.
>=20
> =C2=A0Why is the macro not needed anymore?

Because it's only used by mips_asan_shadow_offset and now we directly
code its content into mips_asan_shadow_offset.

SUBTARGET_SHADOW_OFFSET is only needed if a different subtarget (say,
mips64el-freebsd) needs a different shadow offset.  But for MIPS we
don't have any subtarget other than mips*-linux-gnu* supporting ASAN so
we can omit SUBTARGET_SHADOW_OFFSET and fold the content directly into
the asan_shadow_offset target hook.  RISCV port does the same.

--=20
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University