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=-31.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 BE978C4338F for ; Fri, 30 Jul 2021 21:58:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A738660F9B for ; Fri, 30 Jul 2021 21:58:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233127AbhG3V6g (ORCPT ); Fri, 30 Jul 2021 17:58:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232993AbhG3V5Y (ORCPT ); Fri, 30 Jul 2021 17:57:24 -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 DE13EC06175F for ; Fri, 30 Jul 2021 14:57:17 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id i32-20020a25b2200000b02904ed415d9d84so11145185ybj.0 for ; Fri, 30 Jul 2021 14:57:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=Uxes+3KgPBRk8hTWxCPQ73ggKqkGn4KDKi7P3lIrrmE=; b=oc1f766nm3acj6+MDjD1DuR6HSNGjlZACN22j3AEU+tm2ixEvAsPi4NY9NgAH7/XFB 9hQ2/USNVLptc+faEsxpdHrfRjOxvEh+oIJATF9MXWPrhjgsATyy3b0+RwgsPAICdTHU xoCNXWfdNstm+ki2AarW0LFNSYl1g1WQXW41en2IMhV03rJuj/L3d/lkUpXjFF64qE7n L1UzelynWRnrA8maMsnJI2cRPpeBRsEHD6kRFXI+oQae4Lxz75Q69jrivcmL73vou5Up CDhu9f9OKCKr2dTCgM3JXCHfQ1Vo4K3LXXv7MG7NYKQ3AtVlknBgoAaW2aEbJUW9xg8t p1Gg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=Uxes+3KgPBRk8hTWxCPQ73ggKqkGn4KDKi7P3lIrrmE=; b=DVZgwhJyXNzwPHjVBEf32Vjg2pTmUIL6GUWpwVkPiUnsMpE2bQZxUJqhDJyddQJqvR bm6aGk76LO4IjIIAHBC6Y9aB5ICZfHmVtDmfRYKW9vnsV8zqmUs1w9tBuwC2z87CAYHV UHbnOi5MhuLM6eXHvuqPCIv2DvEsM3SwZBEUKrfFllp3X7SPITfMXdLac2bCsY+MudGt EUskYj+G1ZKUl66cW5Jg7lYVicCx4Y4wRuy81TsaXE872t8lK/V8k+hxYgeuU1ruMvH7 EZjrOKDdcYZ53pBbALhSVcMZwwIIPqG8QetRD3gDkjrb9jTGl7FTqTvJCZcFFL+C3uXZ AzPQ== X-Gm-Message-State: AOAM530N1JksSw08TsGR3ReQIxc+J+IXrdOVTmwlMZNexT/PfrvFvmPt mwOALN27u1odonbjwcl5P7P9WqJS+usjeau8Rb8= X-Google-Smtp-Source: ABdhPJwl6cu/t0jKDt6ug/TY82VXGRaNCSrMNcfRStG8akTrd1tIaDakBYvUhyZJGcozttMUufdQisFyuKxgyRR0HGc= X-Received: from ndesaulniers1.mtv.corp.google.com ([2620:15c:211:202:ca8b:b433:7c1d:90d]) (user=ndesaulniers job=sendgmr) by 2002:a25:cf8a:: with SMTP id f132mr6504203ybg.387.1627682237084; Fri, 30 Jul 2021 14:57:17 -0700 (PDT) Date: Fri, 30 Jul 2021 14:57:07 -0700 In-Reply-To: <20210730215708.276437-1-ndesaulniers@google.com> Message-Id: <20210730215708.276437-3-ndesaulniers@google.com> Mime-Version: 1.0 References: <20210730215708.276437-1-ndesaulniers@google.com> X-Mailer: git-send-email 2.32.0.554.ge1b32706d8-goog Subject: [PATCH v5 2/3] Makefile: infer --target from ARCH 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 , Nathan Chancellor Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: Nathan Chancellor Suggested-by: Masahiro Yamada Acked-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Signed-off-by: Nick Desaulniers --- Changes v3 -> v4: * Reword commit message and oneline, as per Nathan. * Drop documentation change (it's the next patch, could be squashed in, I guess). * Drop LLVM_IAS=1 requirement, as per Masahiro. * Carry Arnd's and Nathan's AB/RB/TB tags, confirmed OK on IRC+Discord. Changes v2 -> v3: * Drop check/requirement for LLVM=1, as per Masahiro. * Change oneliner from LLVM=1 LLVM_IAS=1 to CC=clang LLVM_IAS=1. * Don't carry forward Nathan's RB/TB tags. :( Sorry Nathan, but thank you for testing+reviewing v2. * Update wording of docs slightly. Changes v1 -> v2: * 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. Changes RFC -> v1: * Rebase onto linux-kbuild/for-next * Keep full target triples since missing the gnueabi suffix messes up 32b ARM. Drop Fangrui's sugguested by tag. Update commit message to drop references to arm64. * Flush out TODOS. * Add note about -EL/-EB, -m32/-m64. * Add note to Documentation/. scripts/Makefile.clang | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-) diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 297932e973d4..f983f65dd9f5 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -1,6 +1,32 @@ -ifneq ($(CROSS_COMPILE),) +# Individual arch/{arch}/Makefiles should use -EL/-EB to set intended +# endianness and -m32/-m64 to set word size based on Kconfigs instead of +# relying on the target triple. +ifeq ($(CROSS_COMPILE),) +ifeq ($(SRCARCH),arm) +CLANG_FLAGS += --target=arm-linux-gnueabi +else ifeq ($(SRCARCH),arm64) +CLANG_FLAGS += --target=aarch64-linux-gnu +else ifeq ($(SRCARCH),hexagon) +CLANG_FLAGS += --target=hexagon-linux-gnu +else ifeq ($(SRCARCH),m68k) +CLANG_FLAGS += --target=m68k-linux-gnu +else ifeq ($(SRCARCH),mips) +CLANG_FLAGS += --target=mipsel-linux-gnu +else ifeq ($(SRCARCH),powerpc) +CLANG_FLAGS += --target=powerpc64le-linux-gnu +else ifeq ($(SRCARCH),riscv) +CLANG_FLAGS += --target=riscv64-linux-gnu +else ifeq ($(SRCARCH),s390) +CLANG_FLAGS += --target=s390x-linux-gnu +else ifeq ($(SRCARCH),x86) +CLANG_FLAGS += --target=x86_64-linux-gnu +else +$(error Specify CROSS_COMPILE or add '--target=' option to scripts/Makefile.clang) +endif # SRCARCH +else CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) -endif +endif # CROSS_COMPILE + ifeq ($(LLVM_IAS),1) CLANG_FLAGS += -integrated-as else -- 2.32.0.554.ge1b32706d8-goog