From patchwork Mon Jul 20 18:12:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fangrui Song X-Patchwork-Id: 11674451 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 05000618 for ; Mon, 20 Jul 2020 18:12:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DECD422B4E for ; Mon, 20 Jul 2020 18:12:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ks6dk1mR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728962AbgGTSMr (ORCPT ); Mon, 20 Jul 2020 14:12:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728448AbgGTSMq (ORCPT ); Mon, 20 Jul 2020 14:12:46 -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 955F6C0619D2 for ; Mon, 20 Jul 2020 11:12:46 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 8so22318479ybc.23 for ; Mon, 20 Jul 2020 11:12:46 -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=foQP01o+jLLxWyYMddt7wMxz9LiizEHjChmq39E8dvQ=; b=ks6dk1mRoPvv5K/RguqHzZXRvpQzZ8Sma0KZPaH2f9dcYupIWG8cBMxwDl+AR4xhaV CH1dhBt+6QvtqFvJImE7/TQy6QanJ3RuMki6d2XjchxX6NLmodxKd/KU4im88YsqeISB 0PdFNGrai/DE1DxfYYhfhT+51rxO3HwD7yttKR78i/mA3LXJAncVIiTIkjq0TKeK7F2b sHfctGLF7Zvzut+ZSeq6cb4vKRBUUEW2YtnYgEgH5jCsx4+dhdKZHZk4cn03GDcAWKAt Wmc6voUlwuxFz/qni4DIekfBhxrgjZWS+g8WjfJWc6pKMq891yKv8oGa2AbFZd79eTpv o/EQ== 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=foQP01o+jLLxWyYMddt7wMxz9LiizEHjChmq39E8dvQ=; b=U+xWHDUYIk1DKN9O23Q55snYo/JZ+2kLLITUx1R6UmJW8LOmsAXUknGcOzQOHSTAAa Qv57xXI36Mzi/bXQ3GZIYvTgvWb6DvzHgYkRUIS7Rq8tW8ybgRpkQQsRyfmZe2AOOr1+ GT1K2iTkOb6CTvCWlkVtMOxVeTZcFkNLn8KXdWEloB6IdzyJpR8S4GO3QX31eZ99JHS7 c2H+sYDSJjlz2mo12da2FjUhmKf8VAsvCbwePuQKT1/LhJifyrZTZES7dJq7NADaV32o m7i5WiinXn2NIslTwYDDNH0JqGbvF2POEXa6AJbpJ+stSm97LMDbCgZAisxHJlRv4ClP hmsw== X-Gm-Message-State: AOAM5328SCJAOXLWxg8IaD0gAW3VKL+Z7+llgqoxZKUBdk8W/g4umk7y QklCjKd4+FsTDQ09JYp3USMddASru8HN X-Google-Smtp-Source: ABdhPJzqOaS4ZMz+61ASiwWqZJTx0yklQsWOZm640ChrHnJkwqqqGPaVilq3n2xbqX2bO72REcKFb38xI/gV X-Received: by 2002:a25:fc04:: with SMTP id v4mr37291336ybd.164.1595268765617; Mon, 20 Jul 2020 11:12:45 -0700 (PDT) Date: Mon, 20 Jul 2020 11:12:22 -0700 Message-Id: <20200720181237.3015826-1-maskray@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.rc0.105.gf9edc3c819-goog Subject: [PATCH] Makefile: Fix GCC_TOOLCHAIN_DIR prefix for Clang cross compilation From: Fangrui Song To: Masahiro Yamada , Michal Marek , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Cc: Fangrui Song , Nathan Chancellor Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org When CROSS_COMPILE is set (e.g. aarch64-linux-gnu-), if $(CROSS_COMPILE)elfedit is found at /usr/bin/aarch64-linux-gnu-, GCC_TOOLCHAIN_DIR will be set to /usr/bin/. --prefix= will be set to /usr/bin/ and Clang as of 11 will search for both $(prefix)aarch64-linux-gnu-$needle and $(prefix)$needle. GCC searchs for $(prefix)aarch64-linux-gnu/$version/$needle, $(prefix)aarch64-linux-gnu/$needle and $(prefix)$needle. In practice, $(prefix)aarch64-linux-gnu/$needle rarely contains executables. To better model how GCC's -B/--prefix takes in effect in practice, newer Clang only searches for $(prefix)$needle and for example it will find /usr/bin/as instead of /usr/bin/aarch64-linux-gnu-as. Set --prefix= to $(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE) (/usr/bin/aarch64-linux-gnu-) so that newer Clang can find the appropriate cross compiling GNU as (when -no-integrated-as is in effect). Signed-off-by: Nathan Chancellor Signed-off-by: Fangrui Song Link: https://github.com/ClangBuiltLinux/linux/issues/1099 Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Tested-by: Nick Desaulniers --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 0b5f8538bde5..3ac83e375b61 100644 --- a/Makefile +++ b/Makefile @@ -567,7 +567,7 @@ ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),) ifneq ($(CROSS_COMPILE),) CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) -CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR) +CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(CROSS_COMPILE) GCC_TOOLCHAIN := $(realpath $(GCC_TOOLCHAIN_DIR)/..) endif ifneq ($(GCC_TOOLCHAIN),)