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=-7.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 CCBC7C04AB5 for ; Mon, 3 Jun 2019 17:06:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A3ED02722C for ; Mon, 3 Jun 2019 17:06:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="0rLthD9o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728145AbfFCRGD (ORCPT ); Mon, 3 Jun 2019 13:06:03 -0400 Received: from conssluserg-06.nifty.com ([210.131.2.91]:36556 "EHLO conssluserg-06.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726272AbfFCRGC (ORCPT ); Mon, 3 Jun 2019 13:06:02 -0400 Received: from mail-vs1-f48.google.com (mail-vs1-f48.google.com [209.85.217.48]) (authenticated) by conssluserg-06.nifty.com with ESMTP id x53H5eMA013417; Tue, 4 Jun 2019 02:05:40 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-06.nifty.com x53H5eMA013417 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1559581541; bh=Wh5AphhhG1/9gl6DKkWi7+nu/0r7jfAo3cQVWcxAvMs=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=0rLthD9otS2AiG3E5/GnQ9HdNW3XSBUtY1AgtUllZqLGN/GyYtGBzhjPaMSYYa8oL sDYy02WMCIdG1NQAvo8+T+PaBJJpbLqjMOqZ+hKaF6xEsY0PFLaKozs8Oyj66HCNYt YP1X3LRuifgSA6G3eplD7aY+soa6gJbpJIk7dVlo8nl3o59Tt1QLYf2tL8LRyPdlEt +TzudGaRNejOjJEJuOjAQmxAJ5HzlcXbF4J0coFYXo+jwHkLPvPrYBspaaE7XBJ49Y LaVNCbS6574sp9Kp00/9qm8biOMzj7gcG4w9oKxaMXfw5WDeGuRILPexR5MBjuriIW mWseMnvECxqbQ== X-Nifty-SrcIP: [209.85.217.48] Received: by mail-vs1-f48.google.com with SMTP id l20so11722722vsp.3; Mon, 03 Jun 2019 10:05:40 -0700 (PDT) X-Gm-Message-State: APjAAAVSwB/21Kh3ClJv5BQL5H38tUQG4VAvUNP6PxfGwiHK4FpjHKpT J1cD+JGsYWNxUXWoNUxep1c3202zLfke8aTyFtw= X-Google-Smtp-Source: APXvYqw1j0h7dPq91qeFgfmPoCwM4xqnEZm+YWjuPynChyFgxLznq6Qu/I8GHSTUygSJrljgMIdoqGz9DwIKMY/Ejiw= X-Received: by 2002:a67:1783:: with SMTP id 125mr2680825vsx.54.1559581539601; Mon, 03 Jun 2019 10:05:39 -0700 (PDT) MIME-Version: 1.0 References: <20190516194818.29230-1-jani.nikula@intel.com> <20190524174011.GA23737@ravnborg.org> In-Reply-To: <20190524174011.GA23737@ravnborg.org> From: Masahiro Yamada Date: Tue, 4 Jun 2019 02:05:01 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC 1/3] kbuild: add support for ensuring headers are self-contained To: Sam Ravnborg Cc: Jani Nikula , Linux Kbuild mailing list , Linux Kernel Mailing List , intel-gfx@lists.freedesktop.org, Chris Wilson , Michal Marek Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sam, On Sat, May 25, 2019 at 2:40 AM Sam Ravnborg wrote: > > Hi Jani > > > Sometimes it's useful to be able to explicitly ensure certain headers > > remain self-contained, i.e. that they are compilable as standalone > > units, by including and/or forward declaring everything they depend on. > > > > Add special target header-test-y where individual Makefiles can add > > headers to be tested if CONFIG_HEADER_TEST is enabled. This will > > generate a dummy C file per header that gets built as part of extra-y. > > Very useful, thanks. > I have cooked up something ad-hoc a couple of times but having it as a > standard feature in the build system is much better. > The we can let some of our infrastructure pick up an issues > automatically. > > > > > Cc: Chris Wilson > > Cc: Masahiro Yamada > > Cc: Michal Marek > > Signed-off-by: Jani Nikula > > --- > > Documentation/kbuild/makefiles.txt | 7 +++++++ > > init/Kconfig | 9 +++++++++ > > scripts/Makefile.build | 10 ++++++++++ > > scripts/Makefile.lib | 3 +++ > > 4 files changed, 29 insertions(+) > > > > diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt > > index 03c065855eaf..73df58e5ea0c 100644 > > --- a/Documentation/kbuild/makefiles.txt > > +++ b/Documentation/kbuild/makefiles.txt > > @@ -1036,6 +1036,13 @@ When kbuild executes, the following steps are followed (roughly): > > In this example, extra-y is used to list object files that > > shall be built, but shall not be linked as part of built-in.a. > > > > + header-test-y > > + > > + header-test-y specifies headers (*.h) in the current directory that > > + should be compile tested to ensure they are self-contained, > > + i.e. compilable as standalone units. If CONFIG_HEADER_TEST is enabled, > > + this autogenerates dummy sources to include the headers, and builds them > > + as part of extra-y. > Do we want to restrict this to current directory only? > Sometimes we could use this for headers in include/ but let it > trigger for the relevant subsystem. > So for example drivers/gpu/drm/Makefile will include the rules > for all headers in include/drm/* > > The alternative would be Makefiles (of Kbuild files) > scattered in the directories with headers and then some > infrastructure to visit those. > > Follow patch extend the header-test feature to work with > headers in include/ Following the obj-y pattern, I want to make header-test-y relative to $(obj). > Example: > # Header files from this directory > header-test-y += drm_crtc_helper_internal.h > header-test-y += drm_crtc_internal.h These are described in drivers/gpu/drm/Makefile. > .. > . > # Header files from include/drm > header-test-y += drm/amd_asic_type.h > header-test-y += drm/ati_pcigart.h These are described in $(srctree)/include/Makefile. > ... > > > In the patch $* is used to get the "stem" from the pattern. > This is the filname of the header file without extension. > > > Sam > > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 4d4bf698467a..ca132ab3a551 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -295,11 +295,10 @@ $(obj)/%.lst: $(src)/%.c FORCE > # --------------------------------------------------------------------------- > > quiet_cmd_header_test = HDRTEST $@ > - cmd_header_test = echo "\#include \"$( $@ > + cmd_header_test = echo "\#include <$(2).h>" > $@ > > -# FIXME: would be nice to be able to limit this implicit rule to header-test-y > -$(obj)/%.header_test.c: $(src)/%.h FORCE > - $(call if_changed,header_test) > +$(obj)/%.header_test.c: > + $(call cmd,header_test,$*) > > # Compile assembler sources (.S) > # --------------------------------------------------------------------------- > Agree, this is much better, and it is what scripts/Makefile.asm-generic does. But, you do not need to pass '$*' via the argument. I prefer this: quiet_cmd_header_test = HDRTEST $@ cmd_header_test = echo "\#include \"$*.h\"" > $@ $(obj)/%.header_test.c: $(call cmd,header_test) -- Best Regards Masahiro Yamada