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 E097FC4338F for ; Fri, 30 Jul 2021 20:17:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BDF7B60F4A for ; Fri, 30 Jul 2021 20:17:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231406AbhG3URR (ORCPT ); Fri, 30 Jul 2021 16:17:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230199AbhG3URN (ORCPT ); Fri, 30 Jul 2021 16:17:13 -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 73869C061765 for ; Fri, 30 Jul 2021 13:17:08 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id f3-20020a25cf030000b029055a2303fc2dso11749302ybg.11 for ; Fri, 30 Jul 2021 13:17:08 -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=Jp1qQjnCagMb4RPscvrHWHmxCwM8IS8jZKpJlWaPbYU=; b=ZIByelen7Qxrv8JSbV450jTPClIZHbFqe7AvC0SGq2zfAoivSAREkH3JI9sU/xsF24 huArRbBMyoIH6coS8wNOcsDPUBdgklRqvVA9VWLHD6p/SOjg43ZReJBMnqZ5bFb59j10 2tpP9HSp+9BpZKAEqT+jqxwSakZIq3xdV8VushXKzexRMM52YjlZ8XETc+h3oub9ArIG zXVKiJCR/U163tmLoaHozXmnYMInuXYNvAdQrwWjteE4vUIjwtgQjP5hU99ECJVAplN4 efUdVWt0t3Tpc9IgXmJhoRpRx1FC6158OM7GhqE60vdnShToTUe3WqpTQxhBEuSvwfRj l5vA== 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=Jp1qQjnCagMb4RPscvrHWHmxCwM8IS8jZKpJlWaPbYU=; b=hXQnytQgWOORLJKcT/2CeDQy3ZuZq3ugSQ53+cYj8FmeAdmNgChfaxbGS3f6luBkke +beS3K6s0QtN7jG9AfjjPaVbH4DgVS9lrzqagN5FcYt8WbqBJ7TdxOa6g4YvqtcQJXx0 T1PP0N1VW1gYAzmVo2qN6MnqyMTL2U4ms4nDlDqBV4YLP57tIwbGG4wbbJ0mqCyGE5yH HZLbOaYf1rAUaBrYhQRrZ3RIJ8eAYkP2+362EnD6yF2XnIGiDj8a9gjoq73a53316p2e ziGfzlAhxXVYeo8VCJuTXbEVgJViaBNl9kQ/STUrkdlGWKkr3AwrF2SMABx0wp59ezFY /8KA== X-Gm-Message-State: AOAM531mmmzLN0CvYG8YxowqUYotrGDOEfUFI2GJTWxP70CB4eneiOka ndNCZtW2It1D/RXzlkYXUDbYy85C/etpv+SUH2w= X-Google-Smtp-Source: ABdhPJzKaJChnGwi1dTB1gS74IlPE138ynccwFpvAtOoxDVqV2lpMfja85aSTOtAz+k8wDWFbYZ9RtA1i9+fsihrNYQ= X-Received: from ndesaulniers1.mtv.corp.google.com ([2620:15c:211:202:ca8b:b433:7c1d:90d]) (user=ndesaulniers job=sendgmr) by 2002:a25:aaf1:: with SMTP id t104mr5639126ybi.516.1627676227659; Fri, 30 Jul 2021 13:17:07 -0700 (PDT) Date: Fri, 30 Jul 2021 13:17:00 -0700 In-Reply-To: <20210730201701.3146910-1-ndesaulniers@google.com> Message-Id: <20210730201701.3146910-2-ndesaulniers@google.com> Mime-Version: 1.0 References: <20210730201701.3146910-1-ndesaulniers@google.com> X-Mailer: git-send-email 2.32.0.554.ge1b32706d8-goog Subject: [PATCH v4 1/2] 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 Tested-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