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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_RED autolearn=unavailable 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 F2D5EC432BE for ; Thu, 5 Aug 2021 18:17:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D10436044F for ; Thu, 5 Aug 2021 18:17:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241077AbhHESSH (ORCPT ); Thu, 5 Aug 2021 14:18:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232969AbhHESSG (ORCPT ); Thu, 5 Aug 2021 14:18:06 -0400 Received: from mail-il1-x12d.google.com (mail-il1-x12d.google.com [IPv6:2607:f8b0:4864:20::12d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BB25C061765; Thu, 5 Aug 2021 11:17:52 -0700 (PDT) Received: by mail-il1-x12d.google.com with SMTP id f8so6063094ilr.4; Thu, 05 Aug 2021 11:17:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wrqyGrlzJbaQiQwV6UU8HEiTXlXj9XwABefl+sGFyRs=; b=Ban+ybOof8hxsRRxNPJ2VMCbfacPMCGVJ6mBT1wwqsf/SKwJL6ha3pHlVu5s4o1K+D ZjnJdB511f3l64hjTiG+TGj/S8mBo7lwqzy0C2qtmYawW+XIwckuWt2gUlpUravfo11M KwRYjYZK6ZbuMhmMDcpexL5nRo+02sh+6XdFHtZlr2/554olkE4M/2+Vhz8YIAKChRge 7NBOIq+/giaX3VcA8ZWA1ss56KMpnhyszNCbqMvZbQk1TKrp93CVFmpXZcVvkGYK7kzh iLYFdqXwO86zEaCgUAzFKOFiLConEuxnf7ZJKXR9yIxdipY001SRlAwimravcGjyX2qT 9hVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wrqyGrlzJbaQiQwV6UU8HEiTXlXj9XwABefl+sGFyRs=; b=X+bTYRLYH9mHPGCSkGdj1cqL2f7s7tFwtK9r7oYEV0iVxH7sDiWoxbnnySGQJJWRys tMmbnBsMBtI0VcUf/CRnMILHUFx5aLzONQrDJE8prj+7vO1rbMmqC7/DHQkCJryhx2qV /mkF9FwXvqd4RY3U9MnI4tndGoTgcGD1Vs4Z9YIjdg5yGSeK0DUFiZr6ggrkR7gQjiox VsfiqDwoAqPXngdKtWwGi3BrLpzIuXOKYR2cdEMR7iQevipYMBvwQbb/MsfC+HRNIBT9 QymftHfJKg21+ap4UAbWDF+3mMtXlZjPO75rOatsP6sYbVkocsGy3tPOzwJe1bfvZHEO V/xw== X-Gm-Message-State: AOAM530sznEj1TJP5ML/V9Ha53psEPadgKTi5NoRls/eXG7zKI9mlJ6G T2MQCa2OH6laKJs5brHFTJiDlDfIPiAy91W+eM0= X-Google-Smtp-Source: ABdhPJxk224epffKzdwfCMkaspSFRHJ6HJetar8YOaBxdFYNm/GLKKNPTw3O0uXNvKudsh4EH8kBwidEHDD2CPRBoow= X-Received: by 2002:a92:b74d:: with SMTP id c13mr535113ilm.176.1628187470918; Thu, 05 Aug 2021 11:17:50 -0700 (PDT) MIME-Version: 1.0 References: <20210802183910.1802120-1-ndesaulniers@google.com> <20210802183910.1802120-3-ndesaulniers@google.com> In-Reply-To: <20210802183910.1802120-3-ndesaulniers@google.com> From: Miguel Ojeda Date: Thu, 5 Aug 2021 20:17:40 +0200 Message-ID: Subject: Re: [PATCH v6 2/3] Makefile: infer --target from ARCH for CC=clang To: Nick Desaulniers Cc: Masahiro Yamada , Miguel Ojeda , Fangrui Song , Michal Marek , Arnd Bergmann , linux-kernel , Linux Kbuild mailing list , clang-built-linux , Geert Uytterhoeven , Christoph Hellwig , Linus Torvalds , Nathan Chancellor Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 2, 2021 at 8:39 PM 'Nick Desaulniers' via Clang Built Linux wrote: > > We get constant feedback that the command line invocation of make is too > long when compiling with LLVM. CROSS_COMPILE is helpful when a toolchain > has a prefix of the target triple, or is an absolute path outside of > $PATH. > > Since a Clang binary is generally multi-targeted, we can infer a given > target from SRCARCH/ARCH. If CROSS_COMPILE is not set, simply set > --target= for CLANG_FLAGS, KBUILD_CFLAGS, and KBUILD_AFLAGS based on > $SRCARCH. > > Previously, we'd cross compile via: > $ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make LLVM=1 LLVM_IAS=1 > Now: > $ ARCH=arm64 make LLVM=1 LLVM_IAS=1 > > For native builds (not involving cross compilation) we now explicitly > specify a target triple rather than rely on the implicit host triple. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1399 > Suggested-by: Arnd Bergmann > Suggested-by: Linus Torvalds > Suggested-by: Masahiro Yamada > Suggested-by: Nathan Chancellor > Acked-by: Arnd Bergmann > Reviewed-by: Nathan Chancellor > Signed-off-by: Nick Desaulniers Acked-by: Miguel Ojeda Cheers, Miguel