From patchwork Mon Aug 2 18:39:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Desaulniers X-Patchwork-Id: 12414537 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 CDE82C4338F for ; Mon, 2 Aug 2021 18:39:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A4C6560F55 for ; Mon, 2 Aug 2021 18:39:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229571AbhHBSj1 (ORCPT ); Mon, 2 Aug 2021 14:39:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229551AbhHBSj1 (ORCPT ); Mon, 2 Aug 2021 14:39:27 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4E39C06175F for ; Mon, 2 Aug 2021 11:39:17 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id i32-20020a25b2200000b02904ed415d9d84so19059343ybj.0 for ; Mon, 02 Aug 2021 11:39:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=WTdy23QqSO2DMUu2Ys+7R1vYJMU/74du8VLy/2Y4DPA=; b=vGeI3BYBkGKRi6LHTihmZGbPjuFbs0b9QT5/pySpO0cIAIaUYmd5rtlYB7T4o43Sk4 cDi4l4mFb1gtH6ii4bX12t8K5wqQIUfT2M52ci3FV25/4kXPuTsYvkkQYQsTmU1vbahd LcsJqXOQycyQcdJrtUY/AaDnMMZfe72AYB/Z8djUZDn6drxtGFE1vi++B27uQ7IWCVDM 5HUlJY7Rk4pXHmVaz2tDSBMfV/7T0QpavDpABpYq3UZ4Ejh3MyIpZneo55Trjf3XMxhm EvnkVjJFpp689uLowYjggVmKbcClMvTXsvrPDL0dyqh8g+kvnsXSvEYKgaC9Ov92yahe fM4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=WTdy23QqSO2DMUu2Ys+7R1vYJMU/74du8VLy/2Y4DPA=; b=CQjEy4nzeP+6DDZ87I4Rl4hFhrED9HLCkg662oLFEus7qOQYHKxZUvbXKaylioBQzP UjtjBg+5A0r6UtJUVvEJS8QO22oy899zhSXO/phKWoAPgUjbQ/SyuteYb9sjlJYyxk7a 2Nn72k8Fk4Xw1ySleK+eBKrzGi3JqPU96KtlMzhe29tVmeGaWBTt4KzWkk2GYPEYp7YD 3fmHpGdzhIg3W7XjC3O9+Br8p89uCcDxdj9xgNKA34tjeCFLUcKv1ZBBPStk2/LlfV5x zd80GtoaRtPmQk90K8JWosf7b37cLABAxR0vSIsLta1XIY+PuQc+qo2g8McNjSA0Cprn 1/pQ== X-Gm-Message-State: AOAM530OHtXq8yezhcWhdDwxiWsYNazfCVXh4K8pDEv0n1Y2MaK4EwWI b6aZjPi+Si7ozcniES9iCWFWa8PKkfja3dVTg1Y= X-Google-Smtp-Source: ABdhPJxdctAO0E67NQtmSrPN7peVgzEK7d1WAOiYXjH1alhAAamkoXKrI8QF7jn7wwguFYL6QSB2xEXlmrT45L0zWJ4= X-Received: from ndesaulniers1.mtv.corp.google.com ([2620:15c:211:202:3db0:42c:8665:a4ae]) (user=ndesaulniers job=sendgmr) by 2002:a25:1209:: with SMTP id 9mr23717204ybs.166.1627929556907; Mon, 02 Aug 2021 11:39:16 -0700 (PDT) Date: Mon, 2 Aug 2021 11:39:07 -0700 Message-Id: <20210802183910.1802120-1-ndesaulniers@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.32.0.554.ge1b32706d8-goog Subject: [PATCH v6 0/3] infer --target from SRCARCH for CC=clang From: Nick Desaulniers To: Masahiro Yamada Cc: Miguel Ojeda , Fangrui Song , Michal Marek , Arnd Bergmann , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com, Geert Uytterhoeven , Christoph Hellwig , Linus Torvalds , Nick Desaulniers Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org We get constant feedback that the command line invocation of make is too long. CROSS_COMPILE is helpful when a toolchain has a prefix of the target triple, or is an absolute path outside of $PATH, but it's mostly redundant for a given ARCH. Instead, let's infer --target from SRCARCH, and move some flag handling into a new file included from the top level Makefile. Changes v5 -> v6: * Use indirection as per Linus. * Change hexagon triple to use -musl rather than -gnu. glibc doesn't have support for hexagon, and hexagon-linux-musl is the triple we use in CI. https://github.com/ClangBuiltLinux/continuous-integration2/blob/d659897d1700894d67feb64fe28e298da399a287/generator.yml#L53 * Pick up Fangrui's RB. * Reorder use of Env vars in documentation to use command line parameters instead, for consistency. Changes v4 -> v5: * Include previously missing first patch! Changes v3 -> v4: * Remove the requirement that LLVM_IAS=1 be set, as per Masahiro. * Remove the Documentation/ change from patch 2, as per Masahiro and Nathan. * Add Documentation/ change as patch 3, from Masahiro. * Reword commit message of patch 2, as per Nathan. * Change patch 2 oneline to refer to --target and CC=clang (not CROSS_COMPILE). * Carry Arnd's and Nathan's AB/RB/TB tags, confirmed ok on IRC+discord. Changes v2 -> v3: * Remove requirement that LLVM=1 be set. Instead, if building with just CC=clang LLVM_IAS=1 instead of LLVM=1 LLVM_IAS=1, you should use LD=ld.lld explicitly, or LD=aarch64-linux-gnu-ld. (As per Masahiro) Example: $ ARCH=arm64 make CC=clang LLVM_IAS=1 LD=ld.lld OBJCOPY=llvm-objcopy \ STRIP=llvm-strip -j72 defconfig all (It's still preferable to use LLVM=1 IMO, but this is maximally flexible.) * Change oneliner from LLVM=1 to CC=clang. * Update Docs slightly. Changes v1 -> v2: * patch 1/2 untouched. * Fix typos in commit message as per Geert and Masahiro. * Use SRCARCH instead of ARCH, simplifying x86 handling, as per Masahiro. Add his sugguested by tag. * change commit oneline from 'drop' to 'infer.' * Add detail about explicit host --target and relationship of ARCH to SRCARCH, as per Masahiro. Nick Desaulniers (3): Makefile: move initial clang flag handling into scripts/Makefile.clang Makefile: infer --target from ARCH for CC=clang Documentation/llvm: update CROSS_COMPILE inferencing Documentation/kbuild/llvm.rst | 19 ++++++++++++++++++- MAINTAINERS | 1 + Makefile | 15 +-------------- scripts/Makefile.clang | 35 +++++++++++++++++++++++++++++++++++ 4 files changed, 55 insertions(+), 15 deletions(-) create mode 100644 scripts/Makefile.clang base-commit: d7a86429dbc691bf540688fcc8542cc20246a85b