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=-9.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,INCLUDES_CR_TRAILER,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 81E86C64E7C for ; Wed, 2 Dec 2020 13:05:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31F692222F for ; Wed, 2 Dec 2020 13:05:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729915AbgLBNFX (ORCPT ); Wed, 2 Dec 2020 08:05:23 -0500 Received: from conssluserg-01.nifty.com ([210.131.2.80]:35073 "EHLO conssluserg-01.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725973AbgLBNFW (ORCPT ); Wed, 2 Dec 2020 08:05:22 -0500 Received: from mail-pg1-f179.google.com (mail-pg1-f179.google.com [209.85.215.179]) (authenticated) by conssluserg-01.nifty.com with ESMTP id 0B2D4Obq026281; Wed, 2 Dec 2020 22:04:25 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-01.nifty.com 0B2D4Obq026281 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1606914265; bh=euDqDYPAEo8c1mUJZ8sAnipyVBozjo/dK/LH2E/ZnNg=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=ONsilcmNVaSafGK6T51lZ4URUIrPDczqoDdMj72CU6HGbRa0jUU/5AOsWq5QA6Q4F OMKWsTftrfsJLVaP7sVI3wW1ipGPO0WJNrrl36GbsXwOLnVwsZCVWOf1Vmr+HvYbdV 3BQtTraxn6enLN6a8yFebqKfS3RHnSxp9/LYhRqE4Mfu1bd4P6g3SK0XXyAm0gUwAg 3Y+OphIhMtZJeoLcXw+yFchOZd5l7XZHLknq2y/PmgE5l3aV1c59KJ1rcyyDrb7U8h L6BtFGhwO2rm60X9tAUy6Vy5+DKdAQPkimsmkIeLQDRQK20DaPAU0FNOu5dYaq4Yqd QSoNfTYhp7amQ== X-Nifty-SrcIP: [209.85.215.179] Received: by mail-pg1-f179.google.com with SMTP id t37so1038883pga.7; Wed, 02 Dec 2020 05:04:25 -0800 (PST) X-Gm-Message-State: AOAM530CLrsHDxF+1Nn+5iFvEeB4R1OE68RTPrnSZguywesWQqB1yPdY v6+sIP6wM2/fj8Xn5DYDrDKXyVONhFFyXP1pVcc= X-Google-Smtp-Source: ABdhPJwCzpMRH0jdC7IcItkJ8Sg/5p67zKA8cK34N4+tKICTKOQ/Sa8OrA9ktUc4eHF9ao3tm4BxcPgdiG0AjnJSVvk= X-Received: by 2002:aa7:9606:0:b029:198:14c4:4f44 with SMTP id q6-20020aa796060000b029019814c44f44mr2775545pfg.80.1606914264517; Wed, 02 Dec 2020 05:04:24 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Masahiro Yamada Date: Wed, 2 Dec 2020 22:03:47 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [GIT PULL 2/2] Kconfig updates for v5.10-rc1 To: Linus Torvalds Cc: Emese Revfy , Linux Kbuild mailing list , Linux Kernel Mailing List , Kees Cook Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 2, 2020 at 9:53 PM Masahiro Yamada wrote: > > Hi Linus, > > On Sun, Nov 29, 2020 at 3:28 AM Linus Torvalds > wrote: > > > > On Fri, Nov 27, 2020 at 11:05 PM Masahiro Yamada wrote: > > > > > > As for the cc1plus cost, I got a similar result. > > > > > > Running scripts/gcc-plugin.sh directly > > > took me 0.5 sec, which is a fourth > > > of the allmodconfig run-time. > > > > > > Actually, I did not know this shell script > > > was so expensive to run... > > > > So it turns out that one reason it's so expensive to run is that it > > does a *lot* more than it claims to do. > > > > It says "we need a c++ compiler that supports the designated > > initializer GNU extension", but then it actually includes a header > > file from hell, rather than just test designated initializers. > > > > This patch makes the cc1plus overhead go down a lot. That said, I'm > > doubtful we really want gcc plugins at all, considering that the only > > real users have all apparently migrated to clang builtin functionality > > instead. > > > > Linus > > > The attached patch looks OK to me. > > Just a nit: > Now that the test code does not include any header, > you can also delete > "-I $srctree/gcc-plugins -I $gccplugins_dir/include" > > > If you apply it directly, please feel free to add > > Reviewed-by: Masahiro Yamada BTW, gcc plugins are always compiled with g++. Why do we need to compile the following in the first place? class test { public: int test; } test = { .test = 1 }; I think any C++ compiler will succeed in compiling such simple code. So, test -e "$gccplugins_dir/include/plugin-version.h" looks enough to me. What is the intention of this compile test? -- Best Regards Masahiro Yamada