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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=no 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 D42DCC4361B for ; Tue, 8 Dec 2020 17:05:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A37E23B00 for ; Tue, 8 Dec 2020 17:05:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730633AbgLHRFR (ORCPT ); Tue, 8 Dec 2020 12:05:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730586AbgLHRFQ (ORCPT ); Tue, 8 Dec 2020 12:05:16 -0500 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 327D3C061794 for ; Tue, 8 Dec 2020 09:04:36 -0800 (PST) Received: by mail-wr1-x441.google.com with SMTP id r3so16991295wrt.2 for ; Tue, 08 Dec 2020 09:04:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=RE0ZyDjS9csHRr+SxXqoIyxGXkIUMbwk5h1vfdVY/Jo=; b=sHlLDbSAF1DHYdjAU2pYOuCdGNMyW0m8wRXesU4XKzdY7L8cOA7KxxWcIyncPuP/Rf J5BMIUU1VUeu7dJep3IeI4J1P7fWgkWZfiN9lpjieRsuVKTRBxIXDFl82TdM3yestIgI thpEfYzDr+j8vl8CJgOhItUm8gw0FDjF8yeTypCo6xsHJhelJRzl4ecDaybLPmkiQiGR e/q/jZRaRfzLCm+kaQzRjA2tBOQGX3p//WfiweKUZzk9/4O05taoof1qznyXp35Yd6TG /bAN33zHiuwKk1KFHRqIgDE+XsR/G/d4m50ymoIf6GxU4KdAnbszijyDW0JgPxDv7wWW 8IlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=RE0ZyDjS9csHRr+SxXqoIyxGXkIUMbwk5h1vfdVY/Jo=; b=FskJDswPBDC0xNTcTkI6SRDUiksM00YehAR0Rhb9CKMBlRtD74SX4MSMfx1kAkwINQ 9VCGeKm0yROC1A9KiwXRnnp5wI++6+fR7o39UvcAON2NwXnnmO521Dk8+7aQLstkX/DU TwYJp4kxyxwuyCV4Vm+ADOHsZKz4ie3TBRp2Yq+53HdeNkZz6DaAcR0OAaVh9qm2Hmar r1IrDG5YTyJwMG8etlEe/Mmq6FdoWzsAMxnWJak9drEDCcTG9sNgdiImUlKYMkBLGHkZ 8Pv7gQ7uIs042lukWDuxqmGu6Sf6UYLdsj3BCpcwM+8ThdLZs3qx+xV+SPM2J5NdQPCr GO/Q== X-Gm-Message-State: AOAM531a1xGdmdcvuePEI3OW3nnlYaxeVsL2vCmMZmSJIN4n0LcHBP8n Alou6Wx6DW+Axa6TRICYty+Zfw== X-Google-Smtp-Source: ABdhPJyIqFaUGn8WR2vjV5uSHTLO4k57M1T9jQtvOKXr26z8FICzPerdL4TvpBshQfn1WT/csPmoJQ== X-Received: by 2002:a05:6000:4b:: with SMTP id k11mr2533857wrx.76.1607447074798; Tue, 08 Dec 2020 09:04:34 -0800 (PST) Received: from google.com (203.75.199.104.bc.googleusercontent.com. [104.199.75.203]) by smtp.gmail.com with ESMTPSA id 35sm20913983wro.71.2020.12.08.09.04.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Dec 2020 09:04:33 -0800 (PST) Date: Tue, 8 Dec 2020 17:04:29 +0000 From: Brendan Jackman To: Andrii Nakryiko Cc: bpf , Alexei Starovoitov , Yonghong Song , Daniel Borkmann , KP Singh , Florent Revest , open list , Jann Horn Subject: Re: [PATCH bpf-next v3 12/14] bpf: Pull tools/build/feature biz into selftests Makefile Message-ID: References: <20201203160245.1014867-1-jackmanb@google.com> <20201203160245.1014867-13-jackmanb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 07, 2020 at 06:19:12PM -0800, Andrii Nakryiko wrote: > On Mon, Dec 7, 2020 at 3:00 AM Brendan Jackman wrote: > > > > On Fri, Dec 04, 2020 at 11:00:24AM -0800, Andrii Nakryiko wrote: > > > On Fri, Dec 4, 2020 at 1:41 AM Brendan Jackman wrote: > > > > > > > > On Thu, Dec 03, 2020 at 01:01:27PM -0800, Andrii Nakryiko wrote: > > > > > On Thu, Dec 3, 2020 at 8:07 AM Brendan Jackman wrote: > > > > > > [...] > > > > Ah right gotcha. Then yeah I think we can do this: > > > > BPF_ATOMICS_SUPPORTED = $(shell \ > > echo "int x = 0; int foo(void) { return __sync_val_compare_and_swap(&x, 1, 2); }" \ > > | $(CLANG) -x cpp-output -S -target bpf -mcpu=v3 - -o /dev/null && echo 1 || echo 0) > > Looks like it would work, yes. / > Curious what "-x cpp-output" does? That's just to tell Clang what language to expect, since it can't infer it from a file extension: $ echo foo | clang -S - clang-10: error: -E or -x required when input is from standard input Yonghong pointed out that we can actually just use `-x c`.