From patchwork Sat Aug 31 16:25:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 11124933 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 157E51399 for ; Sat, 31 Aug 2019 16:26:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 97B2022D37 for ; Sat, 31 Aug 2019 16:26:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="nxBWCbZc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728244AbfHaQ0s (ORCPT ); Sat, 31 Aug 2019 12:26:48 -0400 Received: from conuserg-12.nifty.com ([210.131.2.79]:41668 "EHLO conuserg-12.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728119AbfHaQ0r (ORCPT ); Sat, 31 Aug 2019 12:26:47 -0400 Received: from grover.flets-west.jp (softbank126125143222.bbtec.net [126.125.143.222]) (authenticated) by conuserg-12.nifty.com with ESMTP id x7VGQ14v028152; Sun, 1 Sep 2019 01:26:01 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-12.nifty.com x7VGQ14v028152 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1567268761; bh=SLmzLQSSgz61XqmfX34aySvXBG0lEPr1RYwtTQ3yRZs=; h=From:To:Cc:Subject:Date:From; b=nxBWCbZcw9l/4NjxHH+8xdAgWNT6sIEBuw6rXKpR8OAXIAeEUihtiNs7FSwSIn9aJ 52el7fnPLRhAcnXi+5Bp9GAwDVcOYDXpwzhJr9aWLOUQr7PbW8nf4DnDpNM6lFQKj0 sxnPIFOJ6FDe/nDeNzvWSfTexWqJjwy6X8wk2Yl64GTAV99Y36j3O4kUEOcxiAlYVC QTFwJ0djMR2VkXHBZjrY7hXlExkEm0kb8/WdkCKtzsDEOCoZXwrkHY0Pa0qWFPwGcR VElrZ9ql/j9xz7HDjoTNZzRBlS0nZeC253HtmtuaCnXlFJHutKq1Ni0gtjrkoC4N95 oi68cjL3229bQ== X-Nifty-SrcIP: [126.125.143.222] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: Nick Desaulniers , Nathan Chancellor , Sedat Dilek , Masahiro Yamada , Michal Marek , clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/2] kbuild: refactor scripts/Makefile.extrawarn Date: Sun, 1 Sep 2019 01:25:54 +0900 Message-Id: <20190831162555.31887-1-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Instead of the warning-[123] magic, let's accumulate compiler options to KBUILD_CFLAGS directly as the top Makefile does. I think this makes easier to understand what is going on in this file. This commit slightly changes the behavior, I think all of which are OK. [1] Currently, cc-option calls are needlessly evaluated. For example, warning-3 += $(call cc-option, -Wpacked-bitfield-compat) needs evaluating only when W=3, but it is actually evaluated for W=1, W=2 as well. With this commit, only relevant cc-option calls will be evaluated. This is a slight optimization. [2] Currently, unsupported level like W=4 is checked by: $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown) This will no longer be checked, but I do not think it is a big deal. [3] Currently, 4 Clang warnings (Winitializer-overrides, Wformat, Wsign-compare, Wformat-zero-length) are shown by any of W=1, W=2, and W=3. With this commit, they will be warned only by W=1. I think this is a more correct behavior since each warning belongs to only one group. For understanding this commit correctly: We have 3 warning groups, W=1, W=2, and W=3. You may think W=3 has a higher level than W=1, but they are actually independent. If you like, you can combine them like W=13. To enable all the warnings, you can pass W=123. It is shown by 'make help', but not noticed much. Since we support W= combination, there should not exist intersection among the three groups. If we enable Winitializer-overrides for W=1, we do not need to for W=2 or W=3. This is the reason why I think the change [3] makes sense. The documentation says -Winitializer-overrides is enabled by default. (https://clang.llvm.org/docs/DiagnosticsReference.html#winitializer-overrides) We negate it by passing -Wno-initializer-overrides for the normal build, but we do not do that for W=1. This means, W=1 effectively enables -Winitializer-overrides by the clang's default. The same for the other three. Add comments in case people are confused with the code. Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor Tested-by: Sedat Dilek Acked-by: Nick Desaulniers Acked-by: Miguel Ojeda --- Changes in v3: - Added yet more comments. Fix grammatical mistake 'does' -> 'do'. Changes in v2: - Added comments and more commit log scripts/Makefile.extrawarn | 106 ++++++++++++++++++++----------------- 1 file changed, 56 insertions(+), 50 deletions(-) diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index a74ce2e3c33e..d226c5fb13e2 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -1,14 +1,9 @@ # SPDX-License-Identifier: GPL-2.0 # ========================================================================== -# # make W=... settings # -# W=1 - warnings that may be relevant and does not occur too often -# W=2 - warnings that occur quite often but may still be relevant -# W=3 - the more obscure warnings, can most likely be ignored -# -# $(call cc-option, -W...) handles gcc -W.. options which -# are not supported by all versions of the compiler +# There are three warning groups enabled by W=1, W=2, W=3. +# They are independent, and can be combined like W=12 or W=123. # ========================================================================== KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned) @@ -17,58 +12,69 @@ ifeq ("$(origin W)", "command line") export KBUILD_ENABLE_EXTRA_GCC_CHECKS := $(W) endif -ifdef KBUILD_ENABLE_EXTRA_GCC_CHECKS -warning- := $(empty) +# +# W=1 - warnings which may be relevant and do not occur too often +# +ifneq ($(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)),) -warning-1 := -Wextra -Wunused -Wno-unused-parameter -warning-1 += -Wmissing-declarations -warning-1 += -Wmissing-format-attribute -warning-1 += -Wmissing-prototypes -warning-1 += -Wold-style-definition -warning-1 += -Wmissing-include-dirs -warning-1 += $(call cc-option, -Wunused-but-set-variable) -warning-1 += $(call cc-option, -Wunused-const-variable) -warning-1 += $(call cc-option, -Wpacked-not-aligned) -warning-1 += $(call cc-option, -Wstringop-truncation) +KBUILD_CFLAGS += -Wextra -Wunused -Wno-unused-parameter +KBUILD_CFLAGS += -Wmissing-declarations +KBUILD_CFLAGS += -Wmissing-format-attribute +KBUILD_CFLAGS += -Wmissing-prototypes +KBUILD_CFLAGS += -Wold-style-definition +KBUILD_CFLAGS += -Wmissing-include-dirs +KBUILD_CFLAGS += $(call cc-option, -Wunused-but-set-variable) +KBUILD_CFLAGS += $(call cc-option, -Wunused-const-variable) +KBUILD_CFLAGS += $(call cc-option, -Wpacked-not-aligned) +KBUILD_CFLAGS += $(call cc-option, -Wstringop-truncation) # The following turn off the warnings enabled by -Wextra -warning-1 += -Wno-missing-field-initializers -warning-1 += -Wno-sign-compare - -warning-2 += -Wcast-align -warning-2 += -Wdisabled-optimization -warning-2 += -Wnested-externs -warning-2 += -Wshadow -warning-2 += $(call cc-option, -Wlogical-op) -warning-2 += -Wmissing-field-initializers -warning-2 += -Wsign-compare -warning-2 += $(call cc-option, -Wmaybe-uninitialized) -warning-2 += $(call cc-option, -Wunused-macros) - -warning-3 := -Wbad-function-cast -warning-3 += -Wcast-qual -warning-3 += -Wconversion -warning-3 += -Wpacked -warning-3 += -Wpadded -warning-3 += -Wpointer-arith -warning-3 += -Wredundant-decls -warning-3 += -Wswitch-default -warning-3 += $(call cc-option, -Wpacked-bitfield-compat) - -warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) -warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) -warning += $(warning-$(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) - -ifeq ("$(strip $(warning))","") - $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown) -endif +KBUILD_CFLAGS += -Wno-missing-field-initializers +KBUILD_CFLAGS += -Wno-sign-compare -KBUILD_CFLAGS += $(warning) else +# Some diagnostics enabled by default are noisy. +# Suppress them by using -Wno... except for W=1. + ifdef CONFIG_CC_IS_CLANG KBUILD_CFLAGS += -Wno-initializer-overrides KBUILD_CFLAGS += -Wno-format KBUILD_CFLAGS += -Wno-sign-compare KBUILD_CFLAGS += -Wno-format-zero-length endif + +endif + +# +# W=2 - warnings which occur quite often but may still be relevant +# +ifneq ($(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)),) + +KBUILD_CFLAGS += -Wcast-align +KBUILD_CFLAGS += -Wdisabled-optimization +KBUILD_CFLAGS += -Wnested-externs +KBUILD_CFLAGS += -Wshadow +KBUILD_CFLAGS += $(call cc-option, -Wlogical-op) +KBUILD_CFLAGS += -Wmissing-field-initializers +KBUILD_CFLAGS += -Wsign-compare +KBUILD_CFLAGS += $(call cc-option, -Wmaybe-uninitialized) +KBUILD_CFLAGS += $(call cc-option, -Wunused-macros) + +endif + +# +# W=3 - more obscure warnings, can most likely be ignored +# +ifneq ($(findstring 3, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)),) + +KBUILD_CFLAGS += -Wbad-function-cast +KBUILD_CFLAGS += -Wcast-qual +KBUILD_CFLAGS += -Wconversion +KBUILD_CFLAGS += -Wpacked +KBUILD_CFLAGS += -Wpadded +KBUILD_CFLAGS += -Wpointer-arith +KBUILD_CFLAGS += -Wredundant-decls +KBUILD_CFLAGS += -Wswitch-default +KBUILD_CFLAGS += $(call cc-option, -Wpacked-bitfield-compat) + endif