From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,URIBL_RED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1D3FC4338F for ; Sat, 24 Jul 2021 13:47:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACB9460E8F for ; Sat, 24 Jul 2021 13:47:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234324AbhGXNGp (ORCPT ); Sat, 24 Jul 2021 09:06:45 -0400 Received: from conssluserg-04.nifty.com ([210.131.2.83]:36023 "EHLO conssluserg-04.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230449AbhGXNGh (ORCPT ); Sat, 24 Jul 2021 09:06:37 -0400 Received: from mail-pl1-f178.google.com (mail-pl1-f178.google.com [209.85.214.178]) (authenticated) by conssluserg-04.nifty.com with ESMTP id 16ODkfnA024963; Sat, 24 Jul 2021 22:46:41 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-04.nifty.com 16ODkfnA024963 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1627134402; bh=xIH/ltmFtWJmcRQmRg8PWr+q47o4O2EpTM1yT4rZrmI=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=EbqaBoyOEep+aRck6WDXQ8xcyqFY0pHcZo9qObQiyzIvekMZ6Erf+fKq8BxQSIFi9 kbRlgmAphBoSWRVbkmhnKFAyNn5wBoRN8fWf3/NZJXE/HbEtFz4MZE0yDRLKTNKmUZ ZXujegaMA2NLj4g6rvQVgoV3imYjCvqv1tv67H9ivUS0rF6+CNKAhCflm+xyFmns4B cmzV6LCIB3oq4MI2nY0OeHf+7BWS18ZTHjI3QWbt8mVaPyIKjai9YbZjLdXQNdK72t cIOVhoQzbWU2mceldKJFi+7+FcJjQivauis6o8PHy6h8OrAJIDuCztUBYZApt9oEJj meYD7a5ZDwASA== X-Nifty-SrcIP: [209.85.214.178] Received: by mail-pl1-f178.google.com with SMTP id i1so6367784plr.9; Sat, 24 Jul 2021 06:46:41 -0700 (PDT) X-Gm-Message-State: AOAM530ZZS9pg3sXnUWmBvlmqmUloaGcVaPczTMeBmnfQCJ0YAy6Aqw7 mpzptlQIivOSUc7Xk/UvSolPKoSI2tE4mx8Aok4= X-Google-Smtp-Source: ABdhPJwzBx6PuThiVpsvzU+dyvbWRChWN9xv7GsNFlcN5NVApjydszOkLt/Jzms/Uaj3pa+GqUfGGFzJkPrzWii75VM= X-Received: by 2002:a65:609a:: with SMTP id t26mr9654545pgu.175.1627134400955; Sat, 24 Jul 2021 06:46:40 -0700 (PDT) MIME-Version: 1.0 References: <20210708232522.3118208-1-ndesaulniers@google.com> <20210708232522.3118208-3-ndesaulniers@google.com> In-Reply-To: From: Masahiro Yamada Date: Sat, 24 Jul 2021 22:46:03 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 2/2] Makefile: infer CROSS_COMPILE from SRCARCH for LLVM=1 LLVM_IAS=1 To: Geert Uytterhoeven Cc: Arnd Bergmann , Linus Torvalds , Nick Desaulniers , Miguel Ojeda , Fangrui Song , Michal Marek , Linux Kernel Mailing List , Linux Kbuild mailing list , clang-built-linux , Christoph Hellwig , Nathan Chancellor Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 24, 2021 at 4:54 AM Geert Uytterhoeven wrote: > > Hi Yamada-san, > > On Wed, Jul 21, 2021 at 6:05 AM Masahiro Yamada wrote: > > On Wed, Jul 21, 2021 at 4:58 AM Arnd Bergmann wrote: > > > On Tue, Jul 20, 2021 at 7:43 PM Linus Torvalds > > > wrote: > > > > On Tue, Jul 20, 2021 at 1:05 AM Masahiro Yamada wrote: > > > > > > > > We do most of the other heavy lifting in this area in Kconfig anyway, > > > > why not add that compiler choice? > > > > > > > > Obviously it would be gated by the tests to see which compilers are > > > > _installed_ (and that they are valid versions), so that it doesn't ask > > > > stupid things ("do you want gcc or clang" when only one of them is > > > > installed and/or viable). > > > > > > I don't see a good way of making Kconfig options both select the > > > compiler and defining variables based on the compiler, since that > > > would mean teaching Kconfig about re-evaluating all compiler > > > dependent settings whenever the first option changes. > > > > > > I do have another idea that I think would work though. > > > > > > > Hmm? So then any "LLVM=1" thing would be about the "make config" > > > > stage, not the actual build stage. > > > > > > > > (It has annoyed me for years that if you want to cross-compile, you > > > > first have to do "make ARCH=xyz config" and then remember to do "make > > > > ARCH=xyz" for the build too, but I cross-compile so seldom that I've > > > > never really cared). > > > > > > The best thing that I have come up with is a pre-configure step, where > > > an object tree gets seeded with a makefile fragment that gets included > > > for any 'make' invocation. This would set 'ARCH=', 'CROSS_COMPILE', > > > 'CC=' and possibly any other option that gets passed to 'make' as > > > a variable and has to exist before calling 'make *config'. > > > > > > There is no need to add a hook to include such makefile fragment(s). > > > > Quite opposite, you can put your Makefile (in a different filename) > > that includes the top Makefile. > > > > > > I think this is what people are already doing: > > > > > > GNU Make looks for 'GNUmakefile', 'makefile', and 'Makefile' > > in this order. > > Exactly. I only have a few source repositories, but lots of build directories > (I never build in a repo directory). Each build directory has a GNUmakefile: > > build/linux-riscv-starlight$ cat GNUmakefile > MAKEARGS = ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- > > include ~/linux/default.mk > build/linux-riscv-starlight$ cat ~/linux/default.mk > MAKEFLAGS += --no-print-directory > > .PHONY: all $(MAKECMDGOALS) > > all := $(filter-out all Makefile,$(MAKECMDGOALS)) > > all: > @$(MAKE) $(MAKEARGS) $(all) -f Makefile > > Makefile:; > > $(all): all > @: > > %/: all > @: > build/linux-riscv-starlight$ > > Perhaps we could have a "make setup ARCH=foo CROSS_COMPILE=bar" target, > which creates such a GNUmakefile? No, I do not think so. Your GNUmakefile is customized in your way. Other people implement GNUmakefile in their own way. Upstream is not a place to merge everybody's local tools. > P.S. I put the extra logic in ~/linux/default.mk, so I don't have to update all > GNUmakefiles when I want to make a change to the main logic. > > For build dirs where I want to track a specific config, I have a slightly > different version: > > build/linux-m68k-allmodconfig-sun3$ cat GNUmakefile > MAKEARGS = ARCH=m68k KCONFIG_ALLCONFIG=1 > DEFCONFIG = allmodconfig > > include ~/linux/override-oldconfig.mk > build/linux-m68k-allmodconfig-sun3$ cat ~/linux/override-oldconfig.mk > MAKEFLAGS += --no-print-directory > > .PHONY: all oldconfig realoldconfig $(MAKECMDGOALS) > > all := $(filter-out all oldconfig realoldconfig > Makefile,$(MAKECMDGOALS)) > > all: > @$(MAKE) $(MAKEARGS) $(all) -f Makefile > > # Replace oldconfig by $(DEFCONFIG) > oldconfig: > @$(MAKE) $(MAKEARGS) $(DEFCONFIG) -f Makefile > > realoldconfig: > @$(MAKE) $(MAKEARGS) oldconfig -f Makefile > > Makefile:; > > $(all): all > @: > > %/: all > @: > build/linux-m68k-allmodconfig-sun3$ > > That way I can always just type "make oldconfig", and it will do what > I want. > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/CAMuHMdXJBqrpzaSNDJgic14ESiHV6cCcb_5E-st6iniXdmm9_g%40mail.gmail.com. -- Best Regards Masahiro Yamada