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=-31.2 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,URIBL_BLOCKED,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 70841C432BE for ; Mon, 2 Aug 2021 18:39:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AFBA60EBD for ; Mon, 2 Aug 2021 18:39:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231131AbhHBSjg (ORCPT ); Mon, 2 Aug 2021 14:39:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230369AbhHBSjc (ORCPT ); Mon, 2 Aug 2021 14:39:32 -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 7C118C06175F for ; Mon, 2 Aug 2021 11:39:22 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id t101-20020a25aaee0000b0290578c0c455b2so19879023ybi.13 for ; Mon, 02 Aug 2021 11:39:22 -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=4dz3SiE+uajglxOG7tZCdstmLAOcBmHBPB4xfwqxLic=; b=FX1LwuZZPbRbk1DMzYK7B8cWdA3VPi3/o+qSc6Irmgjg0miBtcXtlgER5JxNsybBdQ +enZTkX5KmqA/d/EUeaqZP9xEjJ0XVVXpV3Sx/d7AY98dNgBbKxtgO8Mmojs96l/ysqO esGFPVs9cP1EOrOHavZb1ZqqfaM3CoUlIJzUYLAv3zvAABfDszQzCYjhLXuPby/7uFS+ PytaCzDJTHz09ng4rM5CyVDfK+UdbKlBCI1DAARjBsPx1RK+DwJrmlCmpSDCNXqQPOLu el9r3jFBQ7/7JKmkXSavaJWneWF9Yq6boWl/Km7G4IpZId2+U50vcEhCup7v7A1foqT3 9xIg== 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=4dz3SiE+uajglxOG7tZCdstmLAOcBmHBPB4xfwqxLic=; b=KgMosJpgHB8VB01DNmbmZpUyDD1pt1JdCforIqUhIwWf2tdioYP7QJ+ZxmT7oVyDpw IEFao6NqK4LJzyI9Yzdo/d52rdjNRto9JJxPVPL5ta3XTder8GCRgW7jL1fwOxDuSpdP Vc/S/BCrX6IqD/GEh0eZY2P8Et5/Rw6WQ9e4PxFnC5jFoLBurKpXUOb3+QxgPigeNB2P Iw4NnBubH8zE/2bDoaQxhaK9Y8PIpThsKXk6Vke2IiZqG/loMdruGY/ArZ4z7DOmQCeI 5Ssf1nY+/mLTgRCjFklLtzwyYXAOYFI48byt7n2uaLfnLy6pAYzPKk0i3kf+pSVXDp1W 6hxg== X-Gm-Message-State: AOAM531gFk59WjrIBQWdHQV4BFOqKL8vKdU7ZC0NkK03S06GQvyvI+Fq KfHUM8C9wTe1CSFlkWuSg2j0U5YS2rI23mjkc5c= X-Google-Smtp-Source: ABdhPJwLijclpfvgqa2ibRACKCRjdetSzF0+dGX6mfkpN/yjZFBUsDXL4j4VoCcV0YE/IrAhd8BK2xeCvPrPj3+W+8o= X-Received: from ndesaulniers1.mtv.corp.google.com ([2620:15c:211:202:3db0:42c:8665:a4ae]) (user=ndesaulniers job=sendgmr) by 2002:a25:8445:: with SMTP id r5mr24083636ybm.20.1627929561736; Mon, 02 Aug 2021 11:39:21 -0700 (PDT) Date: Mon, 2 Aug 2021 11:39:09 -0700 In-Reply-To: <20210802183910.1802120-1-ndesaulniers@google.com> Message-Id: <20210802183910.1802120-3-ndesaulniers@google.com> Mime-Version: 1.0 References: <20210802183910.1802120-1-ndesaulniers@google.com> X-Mailer: git-send-email 2.32.0.554.ge1b32706d8-goog Subject: [PATCH v6 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: Linus Torvalds Suggested-by: Masahiro Yamada Suggested-by: Nathan Chancellor Acked-by: Arnd Bergmann Reviewed-by: Nathan Chancellor Signed-off-by: Nick Desaulniers --- Changes v5 -> v6: * Use indirection as per Linus. We now have CLANG_TARGET_FLAGS and a few variables suffixed with $SRCARCH. * Add Linus' SB tag. * Change hexagon target triple from -gnu to -musl. Changes v3 -> v4: * Reword commit message and oneline, as per Nathan. * Drop documentation change (it's the next patch, could be squashed in, I guess). * Drop LLVM_IAS=1 requirement, as per Masahiro. * Carry Arnd's and Nathan's AB/RB/TB tags, confirmed OK on IRC+Discord. Changes v2 -> v3: * Drop check/requirement for LLVM=1, as per Masahiro. * Change oneliner from LLVM=1 LLVM_IAS=1 to CC=clang LLVM_IAS=1. * Don't carry forward Nathan's RB/TB tags. :( Sorry Nathan, but thank you for testing+reviewing v2. * Update wording of docs slightly. Changes v1 -> v2: * Fix typos in commit message as per Geert and Masahiro. * Use SRCARCH instead of ARCH, simplifying x86 handling, as per Masahiro. Add his sugguested by tag. * change commit oneline from 'drop' to 'infer.' * Add detail about explicit host --target and relationship of ARCH to SRCARCH, as per Masahiro. Changes RFC -> v1: * Rebase onto linux-kbuild/for-next * Keep full target triples since missing the gnueabi suffix messes up 32b ARM. Drop Fangrui's sugguested by tag. Update commit message to drop references to arm64. * Flush out TODOS. * Add note about -EL/-EB, -m32/-m64. * Add note to Documentation/. scripts/Makefile.clang | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/scripts/Makefile.clang b/scripts/Makefile.clang index 297932e973d4..1f4e3eb70f88 100644 --- a/scripts/Makefile.clang +++ b/scripts/Makefile.clang @@ -1,6 +1,27 @@ -ifneq ($(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. +CLANG_TARGET_FLAGS_arm := arm-linux-gnueabi +CLANG_TARGET_FLAGS_arm64 := aarch64-linux-gnu +CLANG_TARGET_FLAGS_hexagon := hexagon-linux-musl +CLANG_TARGET_FLAGS_m68k := m68k-linux-gnu +CLANG_TARGET_FLAGS_mips := mipsel-linux-gnu +CLANG_TARGET_FLAGS_powerpc := powerpc64le-linux-gnu +CLANG_TARGET_FLAGS_riscv := riscv64-linux-gnu +CLANG_TARGET_FLAGS_s390 := s390x-linux-gnu +CLANG_TARGET_FLAGS_x86 := x86_64-linux-gnu +CLANG_TARGET_FLAGS := $(CLANG_TARGET_FLAGS_$(SRCARCH)) + +ifeq ($(CROSS_COMPILE),) +ifeq ($(CLANG_TARGET_FLAGS),) +$(error Specify CROSS_COMPILE or add '--target=' option to scripts/Makefile.clang) +else +CLANG_FLAGS += --target=$(CLANG_TARGET_FLAGS) +endif # CLANG_TARGET_FLAGS +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