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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4C65AC433B4 for ; Tue, 13 Apr 2021 23:23:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BDB560C3D for ; Tue, 13 Apr 2021 23:23:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244791AbhDMXX1 (ORCPT ); Tue, 13 Apr 2021 19:23:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230123AbhDMXX1 (ORCPT ); Tue, 13 Apr 2021 19:23:27 -0400 Received: from mail-yb1-xb31.google.com (mail-yb1-xb31.google.com [IPv6:2607:f8b0:4864:20::b31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE4BFC061574 for ; Tue, 13 Apr 2021 16:23:06 -0700 (PDT) Received: by mail-yb1-xb31.google.com with SMTP id z1so20035089ybf.6 for ; Tue, 13 Apr 2021 16:23:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=MdbcAB2zvD5KKWZy3dykqNb02C2FtPGsMKkvUj2cKb8=; b=JhU0euEuY9U/NSdLRamsajWBeXe8+9uxeO3FUloRWYKQ13KYwS4SJGObBSQRKovfpG FZqt87TbJheWLklSlC7ip8X9IhQDmbCoTCm0mNtsMgyBQM/fT/4wAYqr+cranRKrndpb UQ2q8vtYKZR3Yh497tYblx1SqwLSjihgDQg9GWsELmDFHGc/sQtgRUXMz05fJUEY8qt2 UJpdl5LImwrpGl21NXnEnX3/+SKfechhnvy68YZTEcBMLZAWjLQKK0ZoWSAYjWgNBRMA sHetEouE32RMOUG5BzCO62XxkVZwwBMlM7nOX59Hm4wMTxEgvBG/FMJwoBmuaWkPSlJp VnTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=MdbcAB2zvD5KKWZy3dykqNb02C2FtPGsMKkvUj2cKb8=; b=qAFEGMTXLV/cva8ReASTOd7yWwbdasW10fCz1E8y+0odBMW98rgaa0W/QySU/wfPkG TbwKNddC1KlOUu8s2hMHVn0rs3g/X07CJycr8KNZ8zrU1paqWw17V56+wGub9729qBLw AgCWGC8BRq8DWxCWio0U/5CWJlODneJN8P99HcfUJ/kO3sApdSG6cihStmXjCZBkz+ht GNY4QihcivqG/MScuqNxFRxnpRfIRGqakyGvonEhThF1LontHeK0L5RXbtB8mPWkTw1o qin9XCS3XYTFcG2XxFkhjI4tJ9MUpuzr18M0Mm+SR0E+egprLUR0GU6RsH2uAnThDpZp cA0w== X-Gm-Message-State: AOAM532CdfO7VzE/apz1GtTOcKflELt4zoS2iWbRgdV/m/vyGhvCs3DL qTJmUcDgZPmV+k98o9mWsrgjy3GlA1GyB/ystCc= X-Google-Smtp-Source: ABdhPJxTS5t7Zxr36488S2we44D2aF03ZMaum8rhJ9CezFnUaQeiQQ2bOWc68oryZmg+o6NvT0OT8CxXQDSHJB01yvk= X-Received: by 2002:a25:9942:: with SMTP id n2mr47570148ybo.230.1618356186288; Tue, 13 Apr 2021 16:23:06 -0700 (PDT) MIME-Version: 1.0 References: <20210413153408.3027270-1-yhs@fb.com> <20210413153413.3027426-1-yhs@fb.com> In-Reply-To: From: Andrii Nakryiko Date: Tue, 13 Apr 2021 16:22:55 -0700 Message-ID: Subject: Re: [PATCH bpf-next v3 1/5] selftests: set CC to clang in lib.mk if LLVM is set To: Yonghong Song Cc: Nick Desaulniers , bpf , Andrii Nakryiko , Arnaldo Carvalho de Melo , Kernel Team , Sedat Dilek Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Apr 13, 2021 at 3:27 PM Yonghong Song wrote: > > > > On 4/13/21 3:13 PM, Nick Desaulniers wrote: > > On Tue, Apr 13, 2021 at 3:05 PM Andrii Nakryiko > > wrote: > >> > >> On Tue, Apr 13, 2021 at 8:34 AM Yonghong Song wrote: > >>> > >>> selftests/bpf/Makefile includes lib.mk. With the following command > >>> make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel > >>> make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1 V=1 > >>> some files are still compiled with gcc. This patch > >>> fixed lib.mk issue which sets CC to gcc in all cases. > >>> > >>> Cc: Sedat Dilek > >>> Signed-off-by: Yonghong Song > >>> --- > >>> tools/testing/selftests/lib.mk | 4 ++++ > >>> 1 file changed, 4 insertions(+) > >>> > >>> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk > >>> index a5ce26d548e4..9a41d8bb9ff1 100644 > >>> --- a/tools/testing/selftests/lib.mk > >>> +++ b/tools/testing/selftests/lib.mk > >>> @@ -1,6 +1,10 @@ > >>> # This mimics the top-level Makefile. We do it explicitly here so that this > >>> # Makefile can operate with or without the kbuild infrastructure. > >>> +ifneq ($(LLVM),) > >>> +CC := clang > >> > >> Does this mean that cross-compilation with Clang doesn't work at all > >> or is achieved in some other way? > > > > Right, this probably doesn't support cross compilation w/ Clang. > > Rather than invoke `$(CROSS_COMPILE) clang`, you'd do `clang > > --target=$(CROSS_COMPILE)`. Even then, cross linking executables is > > hairy. But at least this should enable native compilation, which is a > > start. > > See https://clang.llvm.org/docs/CrossCompilation.html. > As Nick said, clang prefers --target=$(CROSS_COMPILE) to > indicate cross compilation. User can pass additional > flags (CFLAGS) for cross compilation for the time being. > This is the same as main kernel Makefile. > > ifneq ($(LLVM),) > CC = clang > LD = ld.lld > AR = llvm-ar > NM = llvm-nm > OBJCOPY = llvm-objcopy > OBJDUMP = llvm-objdump > READELF = llvm-readelf > STRIP = llvm-strip > else > CC = $(CROSS_COMPILE)gcc > LD = $(CROSS_COMPILE)ld > AR = $(CROSS_COMPILE)ar > NM = $(CROSS_COMPILE)nm > OBJCOPY = $(CROSS_COMPILE)objcopy > OBJDUMP = $(CROSS_COMPILE)objdump > READELF = $(CROSS_COMPILE)readelf > STRIP = $(CROSS_COMPILE)strip > endif > Ok, sounds good. We can improve cross-compilation separately. Acked-by: Andrii Nakryiko > >> > >> > >>> +else > >>> CC := $(CROSS_COMPILE)gcc > >>> +endif > >>> > >>> ifeq (0,$(MAKELEVEL)) > >>> ifeq ($(OUTPUT),) > >>> -- > >>> 2.30.2 > >>> > > > > > >