LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Nick Desaulniers <ndesaulniers@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
	Khem Raj <raj.khem@gmail.com>,
	Michal Marek <michal.lkml@markovi.net>,
	Jonathan Corbet <corbet@lwn.net>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	clang-built-linux <clang-built-linux@googlegroups.com>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"open list:SIFIVE DRIVERS" <linux-riscv@lists.infradead.org>,
	Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH] scripts/Makefile.clang: default to LLVM_IAS=1
Date: Thu, 5 Aug 2021 11:40:15 -0700	[thread overview]
Message-ID: <CAKwvOdkVuzD68bQuAWS7fS0tat_wdR0bxb=Eh=Te84RtoRgZ8g@mail.gmail.com> (raw)
In-Reply-To: <CAK7LNATWm94K=UcSNn88PyPST38rfe_31vLLpDf=ERPnKnBvVA@mail.gmail.com>

On Thu, Aug 5, 2021 at 8:16 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> On Tue, Aug 3, 2021 at 8:43 AM Nick Desaulniers <ndesaulniers@google.com> wrote:
> >
> > diff --git a/Makefile b/Makefile
> > index 444558e62cbc..b24b48c9ebb7 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -845,7 +845,7 @@ else
> >  DEBUG_CFLAGS   += -g
> >  endif
> >
> > -ifneq ($(LLVM_IAS),1)
> > +ifeq ($(LLVM_IAS),0)
> >  KBUILD_AFLAGS  += -Wa,-gdwarf-2
> >  endif
> >
> > diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
> > index bc74afdbf31e..807f7c94bc6f 100644
> > --- a/arch/riscv/Makefile
> > +++ b/arch/riscv/Makefile
> > @@ -41,7 +41,7 @@ endif
> >  ifeq ($(CONFIG_LD_IS_LLD),y)
> >         KBUILD_CFLAGS += -mno-relax
> >         KBUILD_AFLAGS += -mno-relax
> > -ifneq ($(LLVM_IAS),1)
> > +ifeq ($(LLVM_IAS),0)
> >         KBUILD_CFLAGS += -Wa,-mno-relax
> >         KBUILD_AFLAGS += -Wa,-mno-relax
> >  endif
>
>
>
> Please drop these two hunks.
>
> I will apply my patch instead.
> https://lore.kernel.org/patchwork/patch/1472580/

Sure.  Will send a v2 with Matthew's suggestion as well.

> When we negate a flag that is enabled by default,
> which is a common way?
>  - set it to '0'
>  - set is to empty
>
>
> So, I was wondering if we should support
> not only LLVM_IAS=0 but also LLVM_IAS=.
>
> What do you think?

LLVM_IAS= looks weird (so I agree with Khem's response), but if it's
common/expected then maybe if there's a way to write a concise check
for either =<blank> or =0?  I don't feel strongly about how it's
specified to disable the integrated assembler, but let's sort that out
_before_ I send a v2.

How can you tell the difference between `make CC=clang` and `make
CC=clang LLVM_IAS=`? (maybe that doesn't matter here, as either imply
"don't use clang as the assembler when compiling with clang")
-- 
Thanks,
~Nick Desaulniers

  parent reply	other threads:[~2021-08-05 18:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 23:43 Nick Desaulniers
2021-08-03  1:32 ` Matthew Wilcox
2021-08-05 13:59   ` Masahiro Yamada
2021-08-03  1:42 ` Khem Raj
2021-08-05 15:15 ` Masahiro Yamada
2021-08-05 15:18   ` Khem Raj
2021-08-05 18:40   ` Nick Desaulniers [this message]
2021-08-05 23:48     ` Masahiro Yamada

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAKwvOdkVuzD68bQuAWS7fS0tat_wdR0bxb=Eh=Te84RtoRgZ8g@mail.gmail.com' \
    --to=ndesaulniers@google.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=clang-built-linux@googlegroups.com \
    --cc=corbet@lwn.net \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=masahiroy@kernel.org \
    --cc=michal.lkml@markovi.net \
    --cc=nathan@kernel.org \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=raj.khem@gmail.com \
    --cc=willy@infradead.org \
    --subject='Re: [PATCH] scripts/Makefile.clang: default to LLVM_IAS=1' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).