From patchwork Tue Sep 27 15:31:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Zeng Heng X-Patchwork-Id: 12990792 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE4B7C6FA82 for ; Tue, 27 Sep 2022 15:15:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230482AbiI0PPh (ORCPT ); Tue, 27 Sep 2022 11:15:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230207AbiI0PPg (ORCPT ); Tue, 27 Sep 2022 11:15:36 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2768BCBD; Tue, 27 Sep 2022 08:15:33 -0700 (PDT) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4McNRb3128zHppC; Tue, 27 Sep 2022 23:13:15 +0800 (CST) Received: from huawei.com (10.175.103.91) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 27 Sep 2022 23:15:30 +0800 From: Zeng Heng To: , , , , , , , , , , , , , , CC: , , , , Subject: [PATCH -next] Makefile: add implicit enum-conversion check for compile build Date: Tue, 27 Sep 2022 23:31:25 +0800 Message-ID: <20220927153125.811911-1-zengheng4@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Originating-IP: [10.175.103.91] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500022.china.huawei.com (7.185.36.162) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Provide implicit enum-conversion warning option in general build. When it set enabled, it can detect implicit enum type conversion and find potential conversion errors like below (use "allmodconfig"): drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn20/display_mode_vba_20.c:3904:46: error: implicit conversion from ‘enum ’ to ‘enum odm_combine_mode’ [-Werror=enum-conversion] 3904 | locals->ODMCombineEnablePerState[i][k] = true; | ^ The '-Wenum-conversion' could be regarded as effective check on compile runtime and call attention on potential mistakes. Anothor practical example could be referred to: https://lore.kernel.org/all/CADnq5_OE0yZvEYGu82QJHL9wvVcTFZrmeTgX7URgh7FVA=jqYg@mail.gmail.com "-Wenum-conversion" was firstly introduced from GNU gcc-10. Although "-Wenum-conversion" could be enabled by "-Wextra" when compiling with 'W=1' option, there are many warnings generated by '-Wextra' that cause too much noise in a build. Seeing the details from the following link: https://gcc.gnu.org/onlinedocs/gcc-11.3.0/gcc/Warning-Options.html Because there are still some concerned warnings exist, the patch marks the option disabled in default for avoiding compile failed like using "allmodconfig". Signed-off-by: Zeng Heng --- Makefile | 5 +++++ lib/Kconfig.debug | 7 +++++++ 2 files changed, 12 insertions(+) diff --git a/Makefile b/Makefile index ebd48fc956a3..1790a3624358 100644 --- a/Makefile +++ b/Makefile @@ -880,6 +880,11 @@ endif KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable) +# check implicit enum conversion +ifdef CONFIG_ENUM_CONVERSION +KBUILD_CFLAGS += -Wenum-conversion +endif + # These result in bogus false positives KBUILD_CFLAGS += $(call cc-disable-warning, dangling-pointer) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4f2b81229a2f..a64e06a747d8 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -417,6 +417,13 @@ config FRAME_WARN Setting this too low will cause a lot of warnings. Setting it to 0 disables the warning. +config ENUM_CONVERSION + bool "Warn for implicit enum conversion" + depends on GCC_VERSION >= 100300 + default n + help + Tell gcc to warn at build time for implicit enum conversion. + config STRIP_ASM_SYMS bool "Strip assembler-generated symbols during link" default n